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S0022407320300613
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Sensors based on absorption spectroscopy rely on accurate simulations to obtain quantitative data . The simulations in turn depend on accurate line lists . To test the quality of the ExoMol line list a comparison of a simulation based on the line list to a measured H
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Accuracy of ExoMol H2O absorption simulation comparison with measurement at 1723 K. Over 675 absorption features compared across the 7300 7600 cm. range. ExoMol simulation showed measurable improvement over BT2 in range studied. ExoMol promising for broad band high temp H. O absorption spectroscopy applications.
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S0022407320300650
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Monitoring fine mode aerosol pollutants is one of priorities in national environmental programs . Aerosol Optical Depth and fine mode AOD are key parameters for estimation of particulate matter . POLDER GRASP retrieval provides probably the most detailed aerosol products globally for 2005 2013 . Current studies are focused on understanding the value of new satellite products for potential monitoring of air quality over China . As part of this objective the quantitative evaluation of the products over China a statistical comparison of total AOD fine mode AOD and Fine Mode Fraction with SunSky Radiometer Observation Network products is conducted . Two of available POLDER aerosol products GRASP models and high precision were evaluated at 8 SONET sites over China in this study . The results show the best agreement of the total AOD at 490nm from models approach with AOD from SONET with correlation coefficient of 0.96 slope of 0.9 RMSE of 0.14 and bias of 0.04 with about 76 of retrievals inside of Gfrac ranges . The validation results of the fine mode AOD at 490nm with AOD the fine mode SONET SDA product are quite comparable for both high precision and models approaches with slightly better results for high precision data showing correlation coefficient of 0.95 slope of 0.78 RMSE of 0.14 and bias of 0.07 with about 68 of retrievals inside of Gfrac ranges . The analysis is demonstrated that POLDER GRASP results are one of most suitable aerosol products for characterization of FMF of aerosol . For example compared with MODIS the FMF from POLDER GRASP is significantly closer to SONET SDA FMF with Gfrac increasing from 16.75 to 62.35 . Moreover there is a clear similarity of spatial distribution of the fine mode AOD from GRASP with ground level PM
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A statistical comparison of GRASP total AOD fine mode AOD and Fine Mode Fraction FMF with SunSky Radiometer Observation Network SONET products over China was conducted. Both GRASP models and GRASP high precision products were evaluated at 8 SONET sites. Both SONET SDA and SONET IP retrievals were compared with GRASP fine mode AOD. The comparison between MODIS FMF and GRASP FMF was conducted.
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S0022407320300674
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Electromagnetic scattering on a sphere is one of the most fundamental problems which has a closed form analytical solution in the form of Mie series . Being initially formulated for a plane incident wave the formalism can be extended to more complex forms of incident illumination . Here we present a fast calculation approach to address the scattering problem in the case of arbitrary illumination incident on a spherical scatterer . This method is based on the plane wave decomposition of the incident illumination and weighted integration of Mie solutions rotated to a global coordinate system . Tabulated solutions sampled with an accurately level of sparsity and efficient rotational transformations allow performing fast calculations on electrically large structures outperforming capabilities relatively to other numerical techniques . Our approach is appropriate for real time analysis of electromagnetic scattering from electrically large objects which is essential for monitoring and control applications such as optomechanical manipulation scanning microscopy and fast optimization algorithms .
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Fast computational approach to address scattering problems in the case of an arbitrary illumination is developed. An error estimation method to assess a required number of terms in multipole decomposition of scattered fields is presented. An impact of space sampling density on a scattered field representation solution accuracy is investigated. A tool for fast and accurate optical forces calculations and real time particle tracking analysis is provided.
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S0022407320300698
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Accurate spectroscopic modeling is critical when measuring time resolved state specific chemical kinetics of diatomic molecules . Here a spectroscopic model was developed to accurately simulate oxygen absorption cross sections in the Schumann Runge system for non equilibrium conditions . Cross sections of shock heated oxygen O
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Spectroscopic model developed for the Schumann Runge system. Spectroscopic model extends to high temperatures and non equilibrium conditions. UV pulsed laser absorption spectroscopy acquired O. absorption cross sections. Developed steady state model for vibrational temperature determination above 6000K. Developed spectroscopic models agree with cross section data up to 8400K.
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S0022407320300704
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The forms of potential energy surfaces in particular the potential functions of internal rotation the heights and forms of potential barriers to internal rotation and the energies of torsional levels can control some important properties of molecules and substances as well as the pathways and mechanisms of molecular processes .
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For furfural in the S. state the three low energy vibrational motions are coupled. The reason for one pair of vibrations is the anharmonicity of kinetic energy. The reason for the coupling of other pairs of vibrations is the anharmonicity of potential energy. Accounting for this interaction gives an accurate prediction of frequencies.
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S002240732030073X
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Increase of buffer gas pressure causes redistribution of intensity in the IR absorption bands and indicating the presence of vibrational perturbation changes the first spectral moment value responsible for the band origin position . Band origin shift coefficients for the
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Measurements and calculations of IR band origin shifts for CO. OCS Rg. First spectral moment estimation by direct computation and by DID model. Band shape transformation with increasing buffer gas pressure.
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S0022407320300765
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The mechanisms of coupling between the lattice modes of a two dimensional array consisting of Al nanoparticles and the localized modes of individual Al nanoparticles have been studied in detail . The results were obtained employing the finite difference time domain method and the generalized Mie theory . It was shown that interactions of single particles with 2D lattice modes significantly change the extinction spectra depending on the particle radius and the lattice period . The Rayleigh anomalies of higher orders contribute to formation of hybrid modes resulting in increase of the extinction efficiency in short wavelength range of the spectrum . It was shown that high intensity magnetic modes are excited in aluminum nanoparticles arrays . The patterns of spatial electromagnetic field distribution at the frequencies of hybrid modes have been studied . We note that comprehensive understanding the mode coupling mechanisms in arrays paves the way for engineering different types of modern photonic devices with controllable optical properties .
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The spectral properties of hybrid modes in Al NPs arrays are investigated. Al NPs arrays demonstrate high intensity of magnetic modes resonances. The influence of the particles size on Al NPs arrays are shown. The hybrid modes are the result of eigenmodes and Rayleigh anomalies coupling. The high Q response of Al NPs array can be achieved in all UVvis nearIR range.
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S0022407320300947
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It is difficult to independently obtain aerosol optical parameters at the near infrared wavelength using lidar . A new high spectral resolution technology is proposed to obtain the aerosol extinction coefficient profile at 1064nm . The high spectral resolution detection method by extracting Mie scattering and suppressing CabannesBrillouin scattering is applied in the lidar at 1064nm to improve the detection signal to noise ratio . The system parameters of near infrared high spectral resolution LiDAR N
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Calculating and analysing the different biases of. for delicately correcting extinction coefficient. Using threshold correction method to correct the error caused by the derivation of. and the remaining extinction coefficient is interpolated after threshold correction. A dual channel FPE is designed and used to extract aerosol Mie scattering signal and suppress CabannesBrillouin scattering in N. HSRL. The extinction coefficient profiles of three cases of severe haze day moderate haze day and mild haze day were detected and retrieved by the N. HSRL.
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S0022407320300959
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Product channel specific reaction kinetics at low temperature presents a significant challenge for both experiment and theory but provides essential inputs for astrochemical models of cold interstellar environments . Reaction kinetics studies using chirped pulse Fourier transform microwave spectroscopy provide a potential solution but require the use of a buffer gas to thermalize the reactants and products however collisions with the buffer gas reduce the length of the detected signal the free induction decay through pressure broadening . The effect of this on time domain signals is largely unexplored using CP FTMW spectrometers . A new E band spectrometer has been constructed using previously unavailable equipment in order to maximize its performance for detecting molecules in collisional environments . The design of this spectrometer is described in detail . The pressure broadening of OCS in He was used to test the spectrometer under collisional conditions similar to those that are routinely used to perform reaction kinetics measurements . The corresponding pressure broadening coefficients for transitions in this frequency range were determined at room temperature and the performance of the spectrometer was assessed in relation to recently reported chirped pulse in uniform flow experiments .
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A new E band chirped pulse Fourier transform spectrometer is described in detail. The performance of the spectrometer is characterized. The pressure broadening of transitions of OCS in He are fit to a time domain Voigt model. These results are compared to previous work and applications towards collecting spectra in high pressure environments are discussed.
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S0022407320300960
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Electromagnetic scattering and absorption of multilayered spheres illuminated by a plane wave or a shaped beam are important issues because of the extensively applications . However computation of the internal fields suffers from several difficulties especially when the sphere contains strongly absorbing layers . In the paper reformulation of expressions of electromagnetic fields are made by replacing the unnormalized associated Legendre functions and the Riccati Bessel functions with the normalized associated Legendre functions and the ratios of Riccati Bessel functions . Thus the beam shape coefficients and the Mie coefficients are redefined . An improved recurrence algorithm is presented for calculating the redefined Mie coefficients and numerical calculations are performed for exemplifying the algorithm . It is numerically shown that the reformulation of expressions rescales the involved quantities into the reasonable ranges for machine calculation and the modified algorithm is robust reliable and efficient .
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Recast the analytical expressions of the electromagnetic fields. Redefine the beam shape coefficients and the Mie coefficients. An improved recurrence algorithm is presented for redefined Mie coefficients. Reformulation of expressions rescales the quantities into reasonable ranges.
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S0022407320300996
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A new wavenumber subinterval grouping strategy was deduced to fit multi scale multi group wide band k distribution model used to calculate remote infrared signal of 35 micron wave band emitted by hot combustion gas of hydrocarbon fuel . Further to deal with influence of initialization on the grouping result and calculation accuracies of the MSMGWB model an optimization platform was established to find best combination of grouping results and model s Gauss quadrature schemes . The optimization objective function was established based on weighted calculation errors of MSMGWB model in 18 0D cases using calculation results of line by line model as benchmark . Optimization result was evaluated using other 0D cases with and without influences of various kinds of aerosol in atmosphere . Further evaluations were presented on calculation of remote sensing thermal images for a supersonic aircraft exhaust system and its hot jet . Results indicated that the optimized MSMGWB model has higher calculation accuracies better compatibilities and lower computational cost compared with the previous one . Finally the influence factors of optimization result were discussed .
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Establishing an automatic optimization platform for parameters of MSMGWB model. Optimizing both calculation accuracy and computational cost of MSMGWB model. Improving the compatibility of MSMGWB model with various kinds of aerosol. Analysing the influence factors of optimization result. Calculating remote IR signal of combustion gases under various atmospheric environments.
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S0022407320301187
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An improved model of the aircraft plume is proposed to analyze the effects of alumina particle clusters on ultraviolet radiation signature . In the simulation the scattering effect of particle clusters rather than individual particles on the radiation characteristics in the plume is considered . The modified diffusion limited aggregation method is used to generate the geometry of the cluster example and the scattering characteristics of the particle clusters are calculated by multi sphere T matrix method at first . Then the average optical properties of the particle clusters are calculated and applied to improved spherical harmonic discrete ordinate method together with a new source term about the chemiluminescence emission in the plume the improved radiation model is constructed carefully . The simulation results show that at a small observation angle alumina particle clusters can significantly enhance the radiance of the plume comparing to the individual particle model . Meanwhile the radiance distribution of a more realistic three dimensional plume is presented when both the radial and axial property variation of a whole plume structure are concerned in this model .
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An improved model of the aircraft plume is proposed to analyze the effects of alumina particle clusters on ultraviolet radiation signature. The in scattering source function of the aircraft plume is extracted by the average scattering properties of the particle clusters. The alumina particle clusters can significantly enhance the radiance especially at the aspect angle close to the central axis of the plume. The radiance distribution of a more realistic 3 D plume is presented by this model.
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S0022407320301199
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To enhance solar absorption performance of nanoparticles in the solar thermal conversion applications the optical behavior of Au thorn nanoparticles is studied numerically . A new design strategy toward new nanostructures is provided by coupling with the local surface plasmon resonances and propagating surface plasmon resonances in this work . Results show that Au thorn nanoparticles have the broad absorption region compared with Au sphere nanoparticles due to the multi resonance peaks . Further study reveals that the enhanced absorption mechanism of Au thorn nanoparticles can be attributed to the propagating surface plasmon resonances along the thorn part which is coupled with the surface plasmon resonance of the bulk sphere part . Geometry parameters are also investigated to tune optical properties of Au thorn nanoparticles . Finally solar absorption efficiency calculation shows that Au thorn nanoparticles can achieve the higher solar absorption performance with less particle consumption than Au sphere nanoparticles .
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Optical evolution of gold thorns was studied to improve its SPR peak. Enhanced absorption mechanism of gold thorns was discussed. This work provides design strategies toward new nanostructures.
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S0022407320301217
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Using recently developed version of the configuration interaction method for atoms with open shells we calculate the spectroscopic properties of the mendelevium atom Md
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Using recently developed version of the configuration interaction method for atoms with open shells we calculate electron structure and spectroscopic properties of the mendelevium atom Md. . These include energy levels first and second ionisation potentials electron affinities hyperfine structure and electric dipole transition amplitudes between ground and low lying states of opposite parity. The accuracy of the calculations is controlled by performing similar calculations for lighter homolog of mendelevium the thulium atom and comparing the results with experiments and other calculations. The calculations for Md are to address the lack of experimental data and help in planing and interpreting the measurements. It is the first time to report two possible energy levels bound states 5f. 7s. 7p. and 5f. 7s. 7p. for the negative ion of Md and the electron affinity was predicted to be 0.169 eV.
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S0022407320301230
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We present a detailed investigation of the spectral properties and photoionization of highly charged ions subjected to warm and hot dense plasma environments . A unified framework based on the finite temperature orbital free density functional theory is adopted to describe plasma screening effects on the nucleus electron interaction . Self consistent solving the coupled radial Diarc equations for both bound and continuum wave functions is used through the model EPPP we developed to account the relativistic and plasma shielding effects which is based on the flexible atomic code . The key features of the proposed model are the capacities to systematically include gradient corrections and exchange correlation effects . Additionally numerical tests are conducted to validate the accuracy and stability of the model . The transition energies radiative transition parameters ionization potentials and photoionization cross sections of an exemplary ion Al
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We developed a model EPPP to calculate the PI process under warm dense and dense plasmas. The reduction of energies and ionization potential giving rise to a modification of PI and RR cross sections is highlighted. Our results are validated by comparison with those from other works available in the literature.
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S0022407320301242
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Previously reported works on the spectrum of Cs VII are critically studied using supplementary spectrograms recorded on a 3 m normal incidence vacuum spectrograph in the wavelength region 3001240 at the Antigonish laboratory . We confirmed the results of the earlier work of Gayasov and Joshi on this spectrum . Our analysis is supported by extended calculations with the pseudo relativistic Hartree Fock method with superposition of configuration interactions implemented in Cowan s suite of codes . In this critical evaluation in addition to the accurate energy levels of Cs VII with their uncertainties observed and Ritz wavelengths with uncertainties and transition probabilities the uniformly scaled intensities of Cs VII lines are also presented . A total of 196 lines attributed to 197 transitions enabled us to optimize the energy values of 72 levels in Cs VII spectrum . Furthermore Ritz wavelengths of 141 possibly observable lines are provided along with their transition probabilities .
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Critically evaluated atomic data for six times ionized cesium Cs VII. Accurate energy levels of Cs VII with their uncertainties observed and Ritz wavelengths with uncertainties transition probabilities and uniformly scaled intensities of Cs VII lines were obtained. Theoretical interpretation of the spectrum was made using the Hartree Fock method with relativistic corrections HFR as implemented in Cowan s code.
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S0022407320301254
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We present a novel approach to derive Aerosol Optical Thickness at 0.5 m and the surface reflectance for five spectral channels at native spatial resolution from the measurements of the Polarization and Directionality of Earths Reflectances 3 instrument aboard the Polarization Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar satellite . POLDER had multi spectral and multi viewing capabilities . This publication describes the first step in the design of a high quality AOT and surface property retrieval algorithm enabling the global evaluation of future missions providing multi spectral and multi viewing space borne measurements . The developed retrieval approach is based on the radiative transfer and retrieval model SCIATRAN using an analytical linearized retrieval mode . The surface is parametrized according to the Ross Li model and the aerosol typing was using prescribed types based on the approach by Levy etal . . The minimization using SCIATRAN has been done by solving the quadratic programming problem which minimizes the considered system of equations based on linear constraints . In this study we constrained the retrieval so far only by assuming that the retrieved AOT at 0.5m is larger than 0.01 and smaller than 1.5 . Until now the retrieval is based only upon unpolarized POLDER data and shows promisingly weak dependence on apriori information .
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A novel satellite based full physical retrieval to derive Aerosol Optical Thickness and Surface parameters over vegetation dominated scenes has been developed. The approach is based on the SCIATRAN and relies on multi spectral and multi viewing capabilities of the used satellite instrument. The minimization is done by solving the Quadratic Programming Problem QPP . The retrieval has been applied to POLDER PARASOL data and provides very convincing results at native spatial resolution. A first brief validation with ARM ground based measurements shows good and partly very good agreement R 0.84 .
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S0022407320301278
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In contrast with the optical radiation force induced by conventional lasers of continuous mono frequency wave fields a dynamic or oscillatory mode arises when a beating effect caused by intensity changes over time occurs . The purpose of this analysis is directed toward examining theoretically the dynamic radiation force in optical heterodyning caused by interfering mixing two electromagnetic optical plane waves driven at slightly different frequencies . The example of a dielectric cylinder material having a circular geometric cross section is considered . Based on the integration of Maxwell s stress tensor over the surface of the object in the near field the modal expansion method in cylindrical coordinates is used in conjunction with the short term time average to obtain mathematical series for the longitudinal dynamic optical radiation force per length . The cases of incident TM and TE polarized plane progressive waves are considered . Numerical illustrative results for the dimensionless dynamic radiation force function are performed with particular emphasis on changing the size parameter of the cylinder as well as the normalized difference frequency and time parameters . The results show that the total force is not the mere sum of the components originated by the primary waves . There is an additional cross term factor related to the dynamic component which can not be neglected suggesting that the radiation force phenomenon using beating optical waves is slowly time varying . Moreover a resonance splitting effect in the plots of the dynamic radiation force is observed and discussed . The present analysis has the potential to open a novel method in the development of dynamic oscillatory optical heterodyne tweezers and tractor beams for particle manipulation and characterization .
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The dynamic oscillatory radiation force optical heterodyning method is introduced. This method is based on the oscillatory behavior of the optical force induced by amplitude modulation. Exact mathematical series expansions for the dynamic force are derived and computed. Examples for dielectric cylinders in TM or TE polarized are considered. The results could pave the road for the development of optical oscillatory heterodyne tweezers
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S002240732030128X
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Remote optical measurement techniques are valuable tools for the quantification of combustion generated climate forcing emissions . Leveraging radiometric observations along a detector s line of sight these techniques resolve column density information from which pollutant loading and emission rates can be deduced for an in situ atmospheric plume of a targeted source . One commonly neglected source of uncertainty in such measurements is beam steering the deflection of light as it traverses the plume due to composition and temperature driven gradients in the real refractive index field of the plume . In this work three correction parameters were derived from the radiative transfer equation to enable consideration of beam steering effects on these measurement techniques . A Monte Carlo procedure was performed to derive realistic optical axes through plumes of large eddy simulated gas flares considered to be an extreme case of beam steering due to elevated temperature and composition gradients near the flame . Deflections of light due to beam steering were quantified at wavelengths in the visible spectrum and within three diagnostic relevant infrared absorption bands for methane and carbon dioxide . A conservative empirical model for the degree of beam steering was derived . Moreover from these data correction parameters required to account for the impact of beam steering on perceived incident intensity optical depth and source intensity were found to be negligible at all studied wavelengths relative to typical instrument noise . Thus this work demonstrates that even for the extreme case of a turbulent heated flare plume beam steering has negligible impact on the ability to quantify pollutant loading and emissions .
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Remote optical measurements have potential to be sensitive to beam steering effects. Three dimensionless corrections describe beam steering effects on radiative transfer. Atmospheric plumes of flares are examined as an extreme case of beam steering. Beam steering corrections are negligible for measurements through simulated plumes
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S002240732030131X
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Light transmission through Intraocular lens with glistenings and whitenings are analyzed by using T matrix theory . Visual function is decreased due to glistening and subsurface nanoglistening . Glistening means fluid filled micro sized vacuoles on the other hand whitening is nano sized vacuoles in intraocular lens which lead to light scattering and affect human s vision quality . Glistening observation and light scattering in IOL are observed from the characteristics of glistenings which are size shape refractive index and number of glistenings . When microvacuoles are densely located in IOL light scattering for single particle is not sufficient and multiple light scattering is important to be considered . Therefore the correlation between light transmission and glistening characteristics are investigated from electromagnetic scattering approach called T matrix . For this purpose light scattering simulation software CELES is applied and studied the light transmission in terms of power reflectivity and transitivity . The simulation result can show that light transmittance through IOL to retina and evaluate the quality of the vision by light scattering .
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Effect of glistening characteristics on intraocular lens transmission in the eyes is analyzed from electrical point of view. Light transmission through IOL with glistenings are calculated. Multiple light scattering of glistenings and whitenings are applied by T Matrix. Light scattering simulation software CELES CUDA accelerated simulation of electromagnetic scattering is applied and studied the light transmission.
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S0022407320301394
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Polymers are widely used in many fields such as radiative cooling infrared stealth optical fibers and solar cells . In this work the complex refractive indices of seven polymers such as polydimethylsiloxane polymethyl methacrylate polycarbonate polystyrene polyethylene terephthalate polyvinyl chloride and polyetherimide are measured by spectroscopic ellipsometry combined with the ray tracing method from near infrared to mid infrared bands . The measured results of PDMS have been proved to be accurate by comparing them with previous data in the literature . The obtained refractive indices of polymers in this paper have been compared with the results calculated by the Kramers Kronig relations . Finally we analyze the reasons of absorption peaks of these materials in infrared bands by the vibration of chemical bonds in molecules .
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The complex refractive indices of PDMS with different ratios of composition in infrared bands are measured. The measured refractive indices of polymers in this paper have been compared with the calculated results by the Kramers Kronig relations. The cause of the absorption peak of each polymer is analyzed in the paper.
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S0022407320301412
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Chloromethane is the only organochloride detected in space to date . Its recent observation towards the low mass protostar IRAS 16293 2422 with ALMA offers a prompt for new laboratory studies of CH
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Millimeter wave spectra of CH. DCl observed for the first time. Chlorine hyperfine structure resolved with Lamb dip technique. Spectral predictions to guide radio astronomical searches in the interstellar medium.
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S0022407320301424
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An optical frequency comb referenced quantum cascade laser is used to perform wavelength modulation Lamb dip spectroscopy on a large number of ro vibrational transitions falling in the CHF
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The absolute line center frequencies of 59 lines were measured with a fractional uncertainty ranging from 910. to 2 10. which represents a two order of magnitude improvement with respect to our previous studies A . In addition a detailed comparison with recent high resolution FTIR measurements B was also accomplished bringing out an enhancement in the accuracy performance by more than three orders of magnitude.
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S0022407320301473
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In this work we revise the model describing laser heating of a spherical metallic nanoparticle immersed in transparent oil . We study the generated temperature non uniformity of the ambient medium and its effect on the propagation of the laser beam . Thus the model describes the influence of thermal non uniformity on scattering and absorption of light by the heated particle . Recently different aspects of the heating of NPs by a laser beam have been actively researched . Some experimental works demonstrated an enigmatic dependence of the effective scattering cross section of the heated particle on the intensity of the laser beam illuminating it . The authors of these works labeled the observed effects as saturation and reverse saturation . In this paper we show that the propagation of the incident laser beam in a non uniform oil can by itself be the source of both saturation and reverse saturation els effects .
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Development of the physical model of beam propagation in thermo optically nonlinear and non homogeneous medium. Thermal lensing effect as an origin of saturation and reverse saturation of scattering cross section of a metal nano particle. Theoretical validation of intensity dependence of scattering cross section the heated nano particle and comparison with the experimental one. Comparison with Mie calculation.
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S0022407320301527
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We present a detailed investigation about the vibronic transition parameters as Franck Condon factors r centroids Einstein coefficients and radiative lifetimes for some bands of the second positive
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Spectroscopic properties for five low lying electronic states of N. are obtained using ab initio based analitical potential energy curves. Franck Condon factors r centroids Einstein coefficients and radiative lifetimes for the second positive. and Herman infrared. bands are reported. Perturbations in the spectrum of the second positive system can be attributed to N. C. None. and. state.
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S0022407320301540
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Chlorophyll fluorescence simulation is a hot topic in vegetation remote sensing as it allows to link measurements at leaf and canopy scales to the leaf photosynthetic activity . This work tries to simulate light propagation scattering and fluorescence emission using 3 D vector radiative transfer theory that allows dealing with polarization . The model is called Fluorescence Leaf Canopy Vector Ratiative Transfer FluLCVRT . Realistic 3 D mock up of leaf is used to do simulation based on Monte Carlo ray tracing . Fluorescence is created when radiation passes through chloroplasts . The emission is proportional to the absorbed amount of radiation within the latter . Emitted fluorescence exits chloroplast in a random direction therefore ray tracing is done separately for original radiation and fluorescence . Bidirectional reflectance transmittance and fluorescence are estimated at leaf level within a discrete tessellation for input and output angles that are afterward saved as databases . Then at canopy level ray tracing is done leaf by leaf and at each iteration original radiation is traced in addition to an auxiliary one relative to fluorescence . Both phenomena are governed by their leaf bidirectional distributions and the precalculated databases are used . Results at leaf level point out the variation of the bidirectional distributions . Particularly reflectance and upward fluorescence are characterized by high specular effect and hot spot peak respectively . Horizontally polarized radiation emits fluorescence less than the vertical one because its surface highly reflects radiation in the specular direction . Fluorescence in red and near infrared increases and decreases with respect to chlorophyll content respectively . Fluorescence is emitted from shallow chloroplasts in upward case . Meanwhile in the downward one it is mainly originated from shallow and deep chloroplasts in the red and near infrared bands respectively . At canopy level the same chlorophyll polarization and bidirectional effects are observed except that hot spot peak becomes clear in reflectance . When LAI increases fluorescence saturates at LAI equal 2 and 3 in red and near infrared . Soil contribution in fluorescence is not too much since it does not diffuse an important amount of radiation in the chlorophyll absorption domain . A comparison between our model and Fluspect at leaf level shows differences in scattering and fluorescence . They are mainly due to the decrease of the chlorophyll efficiency in FluLCVRT due to the clumping of the chloroplasts within cell cytoplasm . Such an effect is not modeled in Fluspect .
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Vector radiative transfer to model leaf canopy fluorescence is proposed. Realistic 3 D mock up leaf simulation is adapted. Fluorescence is created when radiation passes through chloroplasts. At level databases of phase functions of scattering and fluorescence are created. At canopy the leaf databases are used to propagate the radiation.
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S0022407320301588
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In the present work we carried out a combined rotational and ro vibrational investigation on 1 1 2 trifluoroethene a relevant unsaturated hydrofluoroolefin recently proposed as refrigerant in mixture with other halogenated compounds . By employing a frequency modulation millimeter wave spectrometer the rotational spectra were recorded in the frequency ranges 8096GHz and 245260GHz for the ground and also the vibrationally excited states
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Analysis of the infrared band. Rotational spectra in the ground and vibrational excited states. FT IR detection of many fundamental bands.
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S0022407320301655
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Scattering of a corrugated plane wave by a sphere is formulated by a pair of waves approach whereby the incident wavefront is considered as a continuum of sinusoidal wavefronts and any such constituent is considered as a pair of equal amplitude plane electromagnetic waves which may be in or out of phase and may assume either of two orthogonal polarisations . All sinusoidal constituents are propagated in the direction of the normal to the incident wavefront . We determine the constituent spectra of a cpw by use of the Fourier transform and ultimately the Lorenz Mie coefficients that apply to cpw scattering by a sphere . We apply our approach to pow scattering by a sphere and Gaussian beam scattering by an off axis sphere . We present numerical results for a
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A pair of waves pow approach to scattering of a corrugated plane wave cpw by a sphere is formulated. The pow theory and code are applied to a sinusoidal wave front incident on a sphere and to Gaussian beam scattering by an off axis sphere. A numerical example demonstrates that particle sizing is possible by adapting a sinusoidal wave front to the scattering sphere.
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S0022407320301667
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This work is dedicated to Stark broadening of singly ionized Molybdenum spectral lines in UV spectrum . We present stark widths of 43 Mo II spectral lines in the wavelength range 275 to 376nm measured at electron density of 1.510
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Stark widths for 43 Mo II spectral lines in NUV region are presented. All Stark widths are the first results in Mo II spectrum. Experiment is conducted in Laser Induced Plasma. Electron density was 1.5e23 m. electron temperature 13000K.
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S0022407320301679
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In a recent work Vispoel etal . optimized the intermolecular potential used in the Modified Complex Robert Bonamy formalism for the H
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Half width and line shifts for 94 536 H. O transitions broadened by N. Temperature dependence of and by the Gamache Vispoel DPL model. Prediction routine for and and their temperature dependence. Nitrogen broadened line list for H. O H. O and H. O based on HITRAN2020.
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S0022407320301734
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The spectral investigation of triply ionized silver has been carried out in the vacuum ultraviolet region . Silver spectra excited through a triggered spark source were photographed on a 3 m normal incidence vacuum spectrograph at St. F. Xavier University Antigonish in Canada . The theoretical study of the spectrum was made through the quasi relativistic Hartree Fock formalism in Cowan s code . The previous work of Ag IV on the 4d
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Revised and extended analysis of triply ionized silver is carried out. Silver spectra were recorded in the wavelength region 350 2080 . 182 energy levels were established among which 22 are new. A total of 1147 transitions are reported along with their transition probabilities.
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S0022407320301783
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Absorption extinction and scattering cross section spectra of optically uniaxial materials are commonly described by the weighted sum approximation also known as
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The effects of material anisotropy on cross section spectra of astronomically relevant materials are investigated. FDTD spectra are compared to spectra of commonly used 1 3 2 3 approximation. Effects of anisotropy lead to shifted bands and or extra bands. Effects of anisotropy remain also in orientation averaged spectra.
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S0022407320301795
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The de noising of lidar signal especially for the range dependent systematic noise always affects the signal to noise ratio of lidar signal and the inversion accuracy of aerosol backscatter coefficient . To avoid this issue a simple de noising operation is implemented to increase the signal to noise ratio and obtain a more accurate aerosol backscatter coefficient . Theoretically the subjectivity of the iterative number of iteration method can be avoided by the simple de noising operation . And the feasibility of the simple de noising operation is investigated by simulation and the routine lidar experimental data . In the near ground the aerosol backscatter coefficient with higher accuracy of about 410 times could be obtained with the simple de noising operation compared with the traditional de noising operation . Moreover the long term stability of the range dependent systematic noise can be found by the experimental results which avoids the frequent measurement of the systematic noise . In addition a higher effective detection altitude is obtained with the simple de noising operation .
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A simple de noising operation is implemented to increase the signal to noise ratio. The operation avoids the subjectivity of the iterative number of iteration method. The more accurate aerosol backscatter coefficient could be obtained in the near ground 2km . A higher effective detection altitude is obtained with the simple de noising operation.
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S0022407320301801
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A computational experimental method for the investigation of photochemical and thermal effect on a methane ethylene flow was developed to determine the saturation intensity of ethylene in the high temperature region up to 1000 1200 K at a pressure near 1 atm . This method included experiments on radiation absorption and a developed numerical model of the cell . Saturation intensity
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A method for investigation of radiation action on a absorbent flow was developed. Temperature field was calculated within the numerical mathematical model. The saturation intensity was found for three powers 60 35 and 12 W. The relaxation time of the excited state of ethylene was estimated.
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S0022407320301849
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Computer simulations employed in Stark broadening calculations are reexamined within the perspective of giving error bars to results . As a rule the calculated spectra exhibit a noisy structure which is inherent to the random number generators involved in the numerical method . Using a variance estimator we quantify the statistical noise on simulated line shapes . Two expressions for the radiated power spectrum which are analytically equivalent but lead to different noise levels are considered . A discussion of this difference is carried out based on an analytical model .
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Computer simulations employed in Stark broadening calculations are reexamined within the perspective of giving error bars to results. A variance estimator is applied to the quantification of the statistical noise present on simulated line shapes. Two expressions for the radiated power spectrum which are analytically equivalent but lead to different noise levels are examined in detail.
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S0022407320301916
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In this work we present a thorough theoretical structure and spectroscopic study of the ground and low lying excited states of RbBa molecule . High level
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The PECs of the 16 S states have been calculated. The PECs of the 33 states arising from spin orbit coupling of 16 S states have been studied. Permanent and transition dipole moments and vibrational energy levels have been calculated for all states. Stimulated black body and spontaneous transition rates of vibrational states of the ground state were evaluated. The possibly of direct laser cooling for RbBa molecule have been discussed.
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S0022407320301941
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In this paper we designed and fabricated a graphene transferred to grating structure with high absorption from 4 m to 14 m. The grating structure was composed of Au SiO
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A graphene transferred to Au SiO. Au grating structure is designed and fabricated. We have experimentally demonstrated high absorption in six sets of graphene grating devices in the infrared region. We deeply analyzed the differences between the experimental and simulation of the dynamic control characteristics of graphene grating structures.
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S0022407320301990
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Hybrid modes originating from the coupling of the Tamm and surface plasmon polaritons excited in a one dimensional resonant photonic structure are demonstrated . The structure represents a photonic crystal bounded by a nanocomposite film consisting of a transparent matrix and silver nanoparticles uniformly distributed over its volume . In comparison with structures on planar metal films the volume concentration and shape of nanoparticles are of great help in configuring the hybrid mode properties including their wavelength and splitting . Also the radiation incidence angle variation opens the possibility of fine tuning the energy spectra of the structure . We demonstrate the high sensitivity of optical sensors based on the resonant photonic structure .
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The possibility of the hybrid TPP SPP modes excitation in resonant photonic crystal structure is shown. The localization of the field at the wavelength of hybrid modes is investigated. The possibility of controlling the spectral properties of hybrid modes by changing the volume concentration of nanoparticles and the angle of incidence of radiation on the structure is demonstrated. The formation of hybrid modes in the case of conjugation of a photonic crystal with an anisotropic nanocomposite film is demonstrated. A model of an optical sensor on TPP SPP modes is proposed.
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S0022407320302004
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This paper describes the third part of a series of investigations to develop algorithms for simultaneous retrieval of aerosol parameters and surface spectral reflectance from GEOstationary Trace gas and Aerosol Sensor Optimization instrument . Since the algorithm is designed for future hyperspectral and geostationary satellite sensors such as Tropospheric Emissions Monitoring of Pollution it is applied to GEO TASO data measured over the same area by different flights as part of the Korea United Stated Air Quality Study field campaign in 2016 . While GEO TASO has a spectral sampling interval of 0.28nm in the visible its data is thinned through a band selection approach with consideration of atmospheric transmittance and different surface types which yields 20 common spectral bands to be used by the algorithm . The algorithm starts with 4 common principal components for surface spectral reflectance extracted from various spectral libraries constraints of surface reflectance and aerosol model parameters are obtained respectively from k means clustering analysis of the Rayleigh corrected GEO TASO spectra and AERONET data . The algorithm then proceeds iteratively with an optimal estimation approach to update PCs and retrieve aerosol optical depth from GEO TASO measured spectra until state vector converges . The comparison of AODs between GEO TASO retrievals
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An algorithm is prototyped for TEMPO to retrieve aerosols surfaces simultaneously. The prototyping is implemented by applying GEO TASO data in KORUS AQ to mimic TEMPO. Spectral AOD retrievals from GEO TASO are validated with AERONET data. Principal components of surface reflectance are retrieved iteratively together with AOD. Next step applications of this algorithm for TEMPO instruments are discussed.
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S0022407320302016
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The accuracy of atmospheric trace gas retrievals depends directly on the accuracy of the molecular absorption model used within the retrieval algorithm . For remote sensing of well mixed gases such as carbon dioxide CO
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Absorption coefficients for the Orbiting Carbon Observatory missions updated to v5.1 for the B10 Level 2 algorithm. Improved spectroscopy for Oxygen A band results in reduced spatial variability in surface pressure retrieval bias. Orbiting Carbon Observatory retrievals are sensitive to changes to the water vapor continuum model.
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S0022407320302041
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Semi transparent materials are increasingly applied in various industrial and scientific applications such as non destructive testing of fiber reinforced polymers by active or passive thermography reflecting and transmitting components in high precision infrared optics and novel thermal insulation systems . Because there is a strong coupling between optical and thermal properties of these materials they pose unique challenges for their modeling and experimental characterization . At PTB the facilities for spectral emissivity measurement of opaque materials have been expanded for the characterization of semi transparent materials in the near mid and far infrared region and for temperatures from 20C to 90C by using a new sample holder . The sample holder was modelled realized and thermometrically characterized . For a first validation of the new setup measurements of natural PTFE foil were performed at temperatures from 27C to 52C and in the wavelength range from 4.5m to 20m yielding the spectral directional emittance spectral optical thickness and spectral reflectance simultaneously .
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Emission transmission and reflection are intertwined for semitransparent materials. Low temperature IR emissivity measurement is complicated by large thermal background. Solution development of a new sample holder and evaluation scheme. Thermographic characterization of realized sample holder. Successful validation using PTFE sample and independent measurements.
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S0022407320302119
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Theoretical calculations are contributing a significantly higher proportion of data to contemporary spectroscopic databases which have traditionally relied on experimental observations and semi empirical models . It is now a common procedure to extend calculated line lists to include ro vibrational transitions between all bound states of the ground electronic state up to the dissociation limit . Advanced
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Overtone vibrational transitions in water ozone and carbon dioxide obey the Normal Intensity Distribution NID earlier established for diatomic molecules. The NID has proved to be a useful tool for validating the intensities of overtone transitions. Manifestation of the NID implies that the intensities of overtone transitions depend on the repulsive branch of the potential energy far from equilibrium. In order to reach high accuracy in the calculations the effect of the repulsive wall must be taken into account even for spectroscopically important transitions. calculations of the potential and dipole moment must extend to regions far from equilibrium.
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S002240732030220X
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The natural light scattering ice contains usually numerous small gas bubbles . The absorption of solar light in ice sheets is studied on the basis of the complete problem solution including modeling the optical properties of ice the spectral radiative transfer and the combined radiative conductive heat transfer in the ice sheet . The obtained analytical solutions make possible a detailed computational study of the problem . The calculated surface and volumetric absorption of solar radiation are used in numerical analysis of solar heating of ice sheets at various sizes and volume fractions of gas bubbles . The effect of the introduced scattering parameter on radiative transfer and solar heating of ice sheets is analyzed .
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The spectral optical properties of ice containing gas bubbles are analyzed. The model for radiative transfer is a scattering ice sheet is developed. The normal hemispherical reflectance of ice sheet with bubbles is obtained. The solar heating of ice sheet containing gas bubbles is calculated.
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S0022407320302272
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The oceanic lidar which has the advantage of profiling the properties of the upper ocean is a promising active remote sensing tool for complementing the passive ocean color remote sensing in the three dimensional observation of ocean . This paper introduces the design and validation of a shipborne multiple field of view lidar . With the input of simultaneous
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A shipborne multiple field of view MFOV lidar has been developed to detect the vertical profiles of seawater optical properties. The detecting results of the MFOV lidar are validated using simulated results with the input of simultaneous. data. The simulation methods include quasi single scattering lidar equation monte carlo MC method and analytical model. The validation results indicate that the oceanic lidar has the feasibility in remote sensing of upper ocean.
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S0022407320302284
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In this paper all electron relativistic MRCI Q calculation has been carried out on electronic and spectroscopic properties of SbCl . In present calculation total 34 S and 74 have been reliably characterized for the first time . The lowest three S states X
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Total 34 S states of SbCl are accurately characterized at the MRCI Q level. The SOC effect makes 34 S states split into 74 states. Transition mechanisms of a. X. None. and b. None. X. None. are illustrated. The SOC effect is indispensible for accurate spectroscopic determinations of SbCl.
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S0022407320302296
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The evaluation of the wavelength parameters of spaceborne oceanic lidar is of great importance to ensure that the lidar system can provide more information of ocean and can be realized in engineering . In this paper the optimum wavelengths of spaceborne oceanic lidar for purposes of ocean detection at coastal and global scales are analyzed mainly in terms of the penetration depth . The global distribution of ocean penetration depth and the corresponding optimum wavelength bands are calculated by using the oceanic optical properties data from Moderate Resolution Imaging Spectroradiometer . Ocean with optimum penetration wavelength of 488 nm covers 61.82 of the global ocean and the optimum wavelength of 443 nm with ocean area share of 14.81 is a good complement for 488 nm . The penetration depths of 96.26 of the global ocean are deeper than 0.8 times the euphotic zone depths by using wavelengths of 488 nm and 443 nm simultaneously . More importantly taking advantage of the characteristic of solar Fe Fraunhoferline and H
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The global distribution of ocean penetration depth and the corresponding optimum wavelength bands are calculated for spaceborne photon counting oceanic lidar. Wavelength bands of 488 nm and 443 nm have good penetration ability and by taking advantage of the characteristic of solar Fe Fraunhoferline 438.355 nm and H Fraunhoferline 486.134 nm the background light can be suppressed and the penetration depth can be further increased. Wavelength of 486.134 nm is the optimum wavelength of single wavelength lidar and the combination of 486.134 nm and 438.355 nm is a good choice for dual wavelength lidar for purpose of global ocean detection.
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S0022407320302363
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Coronavirus virions have spherical shape surrounded by spike proteins . The coronavirus spike proteins are very effective molecular mechanisms which provide the coronavirus entrance to the host cell . The number of these spikes is different it dramatically depends on external conditions and determines the degree of danger of the virus . A larger number of spike proteins makes the virus infectivity stronger .
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Coronavirus virions are spherical 120160nm in diameter with an outer envelope bearing 20 nm long club shaped spike proteins. An increasing of spike proteins number makes virus infectivity stronger. The mathematical model that describes the shape of the coronavirus virion having different spikes proteins number is suggested. Based on this model the characteristics of light scattered by the coronavirus model particles are calculated. Two main features of coronavirus model particles are found in the spectral region near 200nm a minimum of intensity and sharp leap of the linear polarization degree. The effect of the spike proteins number on the intensity and polarization properties of scattered light was studied. It was determined that when the spike proteins number decreasing both intensity minimum and linear polarization leap position shift to shorter wavelengths. Far ultraviolet photopolarimeters are required for a more reliable distinction between viruses and non viruses.
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S0022407320302375
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The study numerically assesses the influences of particle microphysics including shell core ratio black carbon geometry coated volume fraction of BC and size distribution on the scattering Angstrom exponent of polydisperse BC aggregates coated by organics based on the multiple sphere T matrix method . The dependence of coated BC scattering on shell core ratio is highest among all microphysical parameters indicating the significance of ambient measurements of BC shell core ratio . The SAE of coated BC exhibits wavelength dependence with smaller value at smaller wavelength whereas the SAE uncertainty due to wavelength selection is limited with differences less than 10 . The SAE values of coated BC between 450nm and 700nm have broad variation with a range of 0.52.6 for typical coated BC microphysics . The SAE of coated BC is highly sensitive to size distribution and it decreases with particle becoming larger . Compared to size distribution the dependence of the SAE on shell core ratio BC geometry coated volume fraction of BC is generally weak and the SAE of coated BC with larger coated volume fraction of BC becomes less sensitive to BC fractal dimension but more sensitive to shell core ratio . The popular core shell Mie model generally shows acceptable SAE results for heavily coated BC with differences within 10 whereas significant SAE errors can be introduced for thinly coated BC particles . Our work clearly demonstrates the impact of particle size distribution on the SAE of coated BC based on more realistic BC geometries yet suggesting that smaller SAE of coated BC may not always indicate larger particles particularly for thinly coated BC aerosols .
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Smaller SAE may not always indicates larger particles especially thinly coated BC. The importance of particle size distribution on the SAE of coated BC is stressed. The SAE of aged BC is numerically studied with recent observations. Sensitivities of coated BC SAE are numerically investigated. The microphysical factors affecting coated BC SAE are addressed.
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S0022407320302387
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The high resolution absorption spectrum of acetylene has been recorded at room temperature by high sensitivity cavity ring down spectroscopy in the 66277065 cm
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High sensitivity CRDS of acetylene in the 1.45m transparency window 66277065 cm. . More than 3600 transitions assigned to 123 bands of. CH. and. HD. Spectroscopic parameters and Herman Wallis coefficients are derived. A recommended empirical line list of 5260 transitions is generated in the region. Some important deficiencies are evidenced in the HITRAN2016 and ASD lists.
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S0022407320302429
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Determination of overlap function is a key step in the calibration of a high spectral resolution lidar . In this work an iterative based general determination method for overlap function in HSRL is proposed . Error analysis with Monte Carlo simulation is performed and illustrates the algorithm shows high accuracy and has high stability with an accurate lidar ratio assumption . A comparison experiment shows the overlap function from the proposed algorithm agrees well with that from a dual field of view HSRL system . Since no modified optical system in HSRL is needed this method shows great potential in real time recording of overlap function in the HSRL system .
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In this work we presented an iterative based general determination method for retrieving the overlap function in HSRL. No crucial requirement of atmospheric condition nor modified optical system in HSRL is needed in this method. Validation experiment is performed with the HSRL system at zhejiang University. The obtained overlap function meets well with that from the dual FOV method. The IGD method can be used for recording the HSRL overlap function with real time lidar signals because the running time is short enough to be neglected comparing to the acquisition time.
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S0022407320302454
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In this work the hyperfine structure of 26 even parity levels of the manganese atom was investigated with the method of laser induced fluorescence on an atomic beam . Altogether 47 spectral lines were examined with the even parity levels involved as the lower levels . For three levels both the constants
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Hyperfine structure hfs of 47 spectral lines in atomic manganese involving 26 even parity lower levels was recorded by laser induced fluorescence on an atomic beam most of the lower levels were positioned above 30 000cm 1. For three even parity levels both hyperfinestructure constants A and B were determined for the first time for another eight levels new constants B were evaluated for several other levels the hfs constants were revised. Semi empirical analysis of the even parity level system in Mn I was performed in a basis of 36 configurations. Good consistency was found between the experimental hfs constants and those predicted in the semi empirical fit.
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S0022407320302491
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We present exact solutions to the Lippmann Schwinger equation for the scattering of a plane wave by an oblate spheroidal barrier modeled as a boundary wall with coupling strength
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We analytically solve the Lippmann Schwinger equation for an spheroidal barrier. We find solutions for different potentials strengths. The resonance condition is related to the zeros of a radial spheroidal function. We generalize our result for the scattering by N spheroidal barriers.
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S002240732030251X
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In this paper we present results of rotational vibrational and gas temperature distribution study in the cathode sheath region of an abnormal glow discharge in hydrogen and hydrogen argon mixture . For this purpose we used Q branch of the Fulcher diagonal bands d
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Emission spectra of the rotational lines for the hydrogen Fulcher system is recorded. The boundary of the cathode sheath is determined using the polarized h line. Rotational temperature is measured using Fulcher q 33 band. Vibrational temperature is determined from the relative intensities of two consecutive bands. Gas temperature is determined from the population of Q branches for the ground vibrational state.
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S0022407320302600
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The climatologic mean and changes in cloud optical thickness of water and ice clouds in East Asia and their influence on the local radiation budget are studied quantitatively by using the Beijing Climate Center Radiative Transfer Model of BCC RAD combined with satellite observational datasets from March 2000 to February 2018 . Our results show that the annual mean COT over East Asia decreases from the southeast to the northwest and the annual mean COT of water COT
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We find there indeed existed long term change trends of COT for both water and ice clouds in some sub regions over East Asia. It is the first time to quantify both water and ice COT and their change effects on local radiative budget with satellite observational dataset in detail. The major contribution from liquid ice cloud path and cloud effective radius changes to the COT changes are discussed too.
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S0022407320302612
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This study examines the application of the daytime mean and insolation weighted mean solar zenith angles to calculate the diurnally averaged aerosol direct radiative effect
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Mean solar zenith angle for diurnal mean aerosol direct radiative effect DRE. Aerosol DREs using the daytime mean solar zenith angle are too strong. Aerosol DREs using the insolation weighted mean solar zenith angle are too weak. An adjusted insolation weighted mean solar zenith angle is introduced
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S0022407320302661
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Laser spectroscopy methods were used in the investigation of the Zeeman hyperfine structure of 14 lines of atomic niobium in the visible region 585.279637.481nm . We used the laser induced fluorescence method and for higher lying states the fluorescence depletion spectroscopy . The magnetic field of approximately 800G was generated by a permanent neodymium magnet . The source of niobium atoms was a hollow cathode discharge tube . We determined experimentally for the first time the Lande
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Laser spectroscopy methods LIF and FDS were used in measurements of the Zeeman hf structure of atomic niobium. New experimental gJ factors have been determined for 6 energy levels of Nb I. Hfs and gJ data for many other levels of Nb I have been tested and verified. In the computer analysis of the spectra the saturation effect was taken into account.
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S0022407320302703
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The photomultiplier tubes used to measure altitude resolved 532 nm backscatter intensity by the Cloud Aerosol Lidar with Orthogonal Polarization do not recover rapidly following exposure to very high light levels . Instead they exhibit exponentially decaying noise tails that can cause substantial misestimates when determining layer base altitudes and deriving cloud extinction coefficients . Here we present a deconvolution correction algorithm to remove these noise tails in the CALIOP level 1 science data products . The corrected 532 nm attenuated backscatter profiles generated by the deconvolution algorithm are evaluated using the corresponding CALIOP observations at 1064 nm and coincident profiles measured at 532 nm by the NASA Langley airborne high spectral resolution lidar . Results indicate that our deconvolution correction algorithm effectively removes the non ideal PMT recovery effects on the CALIOP level 1 vertical profiles showing excellent performance for surface and water cloud lidar returns when the attenuated backscatter coefficients are greater than 0.01 km
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A deconvolution method is proposed to correct the CALIOP PMTs artifacts at 532 nm. The corrected profiles are validated by CALIOP s 1064nm and HSRL measurements. The proposed algorithm can effectively remove the CALIOP PMTs artifacts. Use of this deconvolution method is highly recommended.
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S0022407320302739
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Diurnal observations of metal Na layer can be implemented by making use of narrowband Faraday filters . On one hand the narrowband spectral filters help to effectively suppress the background noise on the other hand the narrow bandwidth leads to different transmissions of Na layer resonance fluorescence signal and stratosphere Rayleigh scattering signal . The influence of the narrow spectral transmission on Na density retrieval can not be canceled out by Rayleigh normalization and would result in a systematic error . In this paper the Na density retrieval method when narrowband Faraday filters are used in the lidar receiver is discussed based on the transmission spectrum of Faraday filters and echo spectra of Rayleigh scattering and Na fluorescence . The results of Na layer diurnal variations that have been obtained from Na lidar observations at Beijing China are presented . Considerable diurnal variation in Na density on the layer top and bottom are clearly revealed on a logarithmic scale . Intriguingly larger height scale nighttime extensions on the Na layer topside have been frequently observed from early summer to autumn . These observational results can provide valuable evidence for studying solar effect on the metal layer variation atmospheric dynamical and chemical processes in the mesosphere and lower thermosphere region .
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Na density inversion with narrowband filters for daytime measurement is discussed based on spectral analysis. Annual mean diurnal variations of Na layer is obtained showing considerable daytime bottom extension and nighttime top extension. Large height scale nighttime extension on Na layer topside shows obvious seasonal dependence appearing frequently from early summer to autumn while disappearing in winter months. A case of nighttime Na layer top extension shows both gravity wave and tides signatures.
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S002240732030279X
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Imaging lidar techniques featuring of low cost and short blind range have attracted considerable interests during recent years . However the bi static imaging lidar with the transmitter and the receiver placed far away from each other can mainly operate during nighttime . On the other hand the monostatic Scheimpflug lidar with the transmitter and the receiver integrated into a single setup suffers from a low quantum efficiency due to the large tilt angle of the used image sensor . In this paper a monostatic imaging lidar with the image sensor placed parallel to the lens plane of the receiving telescope which is referred to as Shallow Depth Of Field Imaging Lidar has been proposed for atmospheric remote sensing . The SDOFI Lidar system utilizes a 4 W 808 nm multimode laser diode and a 200 mm receiving telescope . The pixel distance relationship has been established according to geometrical optics . All day atmospheric measurements can be achieved with much higher signal to noise ratios during daytime comparing with the SLidar that employs the same optical configurations . The effect of the defocused backscattering image on the lidar signal has also been evaluated in detail . Inter comparison measurements have demonstrated that the lidar signals measured by the SDOFI Lidar generally agreed well with those measured by the SLidar . However the lidar signal and the corresponding aerosol extinction coefficient could be about 11 and 12 overestimated at around 100m respectively due to the defocusing phenomenon of the backscattering image during horizontal measurements . This work has shown a promising feasibility of employing the SDOFI Lidar for atmospheric remote sensing if the overestimation of the aerosol extinction in the near range is tolerable .
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A monostatic imaging lidar with a parallel placed image sensor which is referred to as shallow depth of field imaging lidar SDOFI Lidar has been developed. The pixel distance relationship is established according to geometrical optics. The feasibility of the SDOFI Lidar for atmospheric remote sensing has been investigated through inter comparison measurements with the scheimpflug lidar. The aerosol extinction coefficient obtained by the SDOFI Lidar is about 12 overestimated at around 100m due to the defocusing effect of the backscattering image.
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S0022407320302867
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We analyze the results of numerically exact computer modeling of spectral dependences of the intensity of light scattered by different aggregates of submicron spherical particles in the visible range and compare them to those of individual homogeneous spheres . The computations are performed using the Lorenz
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Spectra of light reflected by fractal clusters of submicron particles are analyzed. Interference of waves singly scattered by constituents induces new collective details. Collective maximum is resistant to increasing the constituent number after some value. Number of constituents providing a stable collective maximum depends of the structure . Collective maximum is rather weakly affected by variations in the constituent sizes.
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S0022407320302880
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The Baseline Surface Radiation Network is a project of the Data and Assessments Panel from the Global Energy and Water Exchanges under the umbrella of the World Climate Research Programme . Currently in the archive there are data from 67 sites located in all seven continents spanning from 1992 to the present . The original BSRN records are at 1 2 3 or 5 minute intervals and sophisticated quality control procedures have been developed to eliminate erroneous records before hourly daily and monthly means are computed . The resulting gaps from quality control however give rise to uncertainties in computed temporal averages on various scales . There are two types of total shortwave downward fluxes The Global 1 which is the sum of direct horizontal and diffuse irradiances observed using the pyrheliometer and radiometer respectively and is recommended by the BSRN committee for its higher precision and the Global 2 which is observed using the pyranometer . It has been found that compared to Global 2 Global 1 is more susceptible to errors thus resulting in more gaps in the original records . Here we examine the effect of quality control on the monthly mean Global 1 and Global 2 and attempt to quantify the resulting uncertainties through analysis of the quality control procedure and averaging algorithm and comparison with the NASA GEWEX Surface Radiation Budget dataset . The SRB project is now making progress toward its Release 4.0 Integrated Products with changes in both algorithm and inputs on the basis of its Release 3.0 products . The preliminary results from Rel . 4.0 IP span 34 years continuously from July 1983 to June 2017 on a 1 by 1 quasi equal area grid system in the form of 3 hourly daily and monthly means . It is found that Global 2 generally has fewer missing records and is less affected by the quality check procedure on average the monthly mean Global 1 and Global 2 differ by less than 1 W m
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Derived uncertainties of BSRN Global 1 and Global 2 monthly means due to missing hourly means using Monte Carlo method. Compared BSRN Global 1 and Global 2 with and without quality check. Quality check affects Global 1 less than Global 2. Quality checked monthly mean Global 1 and Global 2 on average differ by less than 1 W m. Preliminary GEWEX SRB GSW V4.0 IP agree best with quality checked Global 1.
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S0022407320302892
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We propose a thermal modulation structure composed of two identical Weyl semimetal slabs separated by a nanoscale vacuum gap . Following Maxwell s equations and the dielectric tensor of the WSM we derive the reflection matrix at the WSM vacuum interface . Based on fluctuation electrodynamics the effects of the Fermi level the number of Weyl nodes the separation between Weyl nodes and the thickness of vacuum gap on the heat transfer coefficient and the thermal modulation contrast are numerically discussed . It is found that the WSM possesses stronger near field radiative ability in the low frequency region where the coupled surface plasmon polaritons between the WSM slabs play a dominant role . By continuously tuning the Fermi level from 0.01 to 0.15 eV a large modulation contrast as high as 58.5 is obtained at T 300K while in the low temperature interval
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The WSM based nanostructure can greatly improve near field thermal modulation. Tuning the Fermi level is an efficient way to modulate the near field heat flux. The near field radiation is dominated by the coupled SPPs between the WSM slabs. A large thermal modulation contrast exceeding 58 is obtained at T 300K. The maximum modulation contrast exceeds 482 at 150K for a vacuum gap of 20nm.
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S0022407320302909
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Laser based object detection has been recognized as the most reliable technique for applications such as night vision 3D imaging and especially underwater object detection . The key information is extracted from the reflected laser pulse after interacting with the target which surface directly affects the system performance . Due to the variety of the target types it is necessary to investigate the surface characteristics and their effects on the performance of an underwater pulse laser ranging system . In this paper the influence of target surface characteristics namely the type of materials colors and roughness on the reflectance and system performance are investigated through theoretical analysis using the Bidirectional Reflection Distribution Function and Laser Detection and Ranging model . An underwater peak detection pulse laser ranging system is developed to validate the results of a theoretical study . Both experimental and theoretical results clearly show that the system performance depends on the reflectance caused by the three characteristics of the target surface . This comprehensive research provides a handy reference with regards to the surface material colors and roughness for future improvement or correction in this domain .
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Analytical descriptions for target surface characteristic are thoroughly investigated and compared based on bidirectional reflection distribution function BRDF and laser detection and ranging LADAR model. According to our theoretical analysis an underwater peak detection pulse ranging system is built to get the reflection ratio and range accuracy for different target surfaces to verify the theoretical investigation. Experimental and theoretical results show that the reflectance and accuracy depend on the surface characteristics. Our studies overcome the limitation of previous studies which focuses on improvement of system instruments performance and overcome working environment influence.
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S0022407320302958
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The composition of the Earth s atmosphere is changing . The Atmospheric Chemistry Experiment satellite measures infrared transmission spectra of the atmosphere using the Sun as a light source . ACE provides a global view of atmospheric composition from altitude composition profiles for 44 molecules starting in February 2004 . Altitude latitude abundance distributions and composition trends for more than 16 years are presented and briefly discussed . The ACE trends provide a quantitative state of the atmosphere report .
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Altitude latitude distributions for 44 atmospheric molecules. Sixteen year trends in composition from atmospheric chemistry experiment ACE satellite. Solar occultation measurements with ACE fourier transform spectrometer ACE FTS . Volume mixing ratios VMRs profiles retrieved with ACE FTS.
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S0022407320303046
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Light scattering by particles immersed in an absorbing host medium has been an important issue in many fields such as ocean optics atmospheric radiation remote sensing and so on . The traditional theory ignores the effect of host medium absorption on particle scattering which may result in inaccurate results . In this paper the scattering coefficient extinction coefficient and phase function of the dispersed medium consisting of optically soft particles are investigated with considering the effect of host medium absorption on particle scattering . The results are based on the recently developed Mie theory for the absorbing host medium . It is found that neglecting the host medium absorption on particle scattering will result in a small change in extinction coefficients but a great change in scattering coefficients . Meanwhile the relative error of scattering coefficients caused by using the conventional Mie theory increases obviously with the increase of particle size and the absorption index of the host medium while the relative error of extinction coefficients fluctuates with the particle size . Moreover the relative error of scattering coefficients of polydisperse particles is more significant than that of monodisperse particles .
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The extinction coefficient scattering coefficient and phase function of the dispersed medium consisting of optically soft particles are investigated with considering the effect of host medium absorption on particle scattering. Neglecting the host medium absorption on particle scattering has a more significant influence on the scattering coefficient than the extinction coefficient in most cases. The relative error of scattering coefficients of polydisperse particles is larger than that of monodisperse particles. The differences in phase functions obtained by using the conventional Mie theory and modified Mie theory are negligible for particles with small size but become obvious with the increase of particle size.
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S0022407320303137
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Although charged particles exist widely in a plasma environment or an electrolyte the problem of electromagnetic scattering by a charged cylinder has remained unsolved . In this paper using the tangential boundary conditions with a surface current induced by excess surface charges we calculate the extinction scattering and absorption efficiencies for a charged infinite cylinder upon which a plane wave is normally incident . For two polarizations of the incident light we show the different effects of the excess surface charges on the optical efficiencies . For
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The expansion coefficients of the electromagnetic fields are derived for a charged infinite cylinder under the normal incidence of plane waves. The extinction and absorption efficiencies of the charged cylinder are calculated with the different density of excess surface charges. For p polarized incidence a platform structure in extinction efficiencies for the small size parameter corresponds to the light absorption by the excess surface charges. For s polarized incidence the excess surface charges can induce a new resonance and a shift of anomalous resonances. Both the new resonances and the anomalous resonances shift to a larger size parameter with an increasing surface charge density which has been shown for a charged MgO cylinder near the longitudinal optical phonon frequency.
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S0022407320303186
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This study retrieves and evaluates aerosol layer height during spring dust storm events observed over the Taklimakan and Gobi Desert . A novel strategy is proposed to identify single or multi layered aerosol scenarios in wide swath passive sensor images from Ozone Mapping and Profiler Suite and Moderate Resolution Imaging Spectroradiometer aided by profiles of Cloud Aerosol Lidar with Orthogonal Polarization and use different sets of look up tables to retrieve ALH accordingly . The strategy combines the advantage of two independent methodsthe ability to expand three dimensional atmospheric structure using the spectral radiance matching method and the ability to estimate ALH over a long distance using the aerosol single scattering albedo and height estimation method . From 2012 to 2016 ALH during 4 severe dust storms is retrieved over the Taklimakan and Gobi Desert . Analysis shows that the average height and occurrence frequency retrieved fall in the same range with results from previous studies . Comparisons with ALH inferred from CALIOP profiles indicate that the combined ASHE SRM method has improved the overall performance . The estimated ALH correlates well
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A novel strategy is proposed to retrieve aerosol layer height for single or multi layered aerosol scenarios in wide swath passive sensor images aided by profiles of CALIOP. Aerosol layer height is retrieved during 4 spring dust storm events the average is 5.20km in the taklimakan region and 5.12km in the gobi region. The estimated aerosol layer height correlates well. 0.68 with values measured by CALIOP and the mean absolute difference MAD is 1.341.02km.
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S0022407320303277
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We present high accuracy measurements of the spectroscopic parameters of eight nitrous oxide transitions mainly belonging to the P branch of the
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We present an optical feedback laser absorption spectrometer OF LAS operating at 2 m wavelength and assisted by an optical frequency comb. We used a multispectrum fitting approach involving the uncorrelated and symmetric version of the Hartmann Tran profile. Evidence for multiple non Voigt mechanisms affecting the experimental spectra was found. We retrieved line intensity factors with an overall uncertainty within 0.38 . We also determined self broadening coefficients speed dependence components of the collisional line broadening and Dicke narrowing parameters. We compared the measured line intensities with those from HITRAN and NOSD 1000 databases. The agreement is more satisfactory for the NOSD 1000 rather than HITRAN.
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S0022407320303307
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Circularly polarized light can induce additional mode conversion when it interacts with a material that rotates the orientation of the plane of polarization which is known as optical rotation or rotary polarization . The effect of this additional mode conversion phenomenon is studied in the framework of the optical radiation force theory . The time averaged force acting on an infinitely long perfect electromagnetic conductor circular cylinder is considered . The multipole modal expansion method in cylindrical coordinates is utilized to derive exact series expansions for the components of the longitudinal radiation force per length applicable to any range of frequencies . Numerical predictions for the radiation force function and its components clearly demonstrate the contribution of the co polarized and cross polarized waves .
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Optical radiation force on a cylindrical material exhibiting rotary polarization is examined. The example of a perfect electromagnetic circular cylinder is considered. A left handed circularly polarized plane wavefield is assumed. The effects of the cross polarized waves and TM TE mode conversion is noted and discussed. Mode conversion contributions cannot be neglected for optical materials exhibiting rotary polarization.
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S0022407320303319
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Selective spectra of absorber and emitter have great effects on the solar thermophotovoltaic performance . In this work a systematic thermal analysis of the STPV system was conducted to optimize the selective absorber and emitter . For the ideal absorber and emitter the maximum STPV efficiency can be achieved at the cutoff wavelength of 1.2 m for the ideal absorber and emitted spectrum width of 1.0 m for the ideal emitter . Increasing concentrated factor of solar radiation from 1 to 100 can enhance the total STPV efficiency from 10.4 to 20.3 indicating that the large incident solar intensity can enhance the STPV efficiency . In addition increasing ratios of length to gap eg
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A systematic thermal analysis was conducted to optimize STPV performance. Increasing concentrated factor and view factor can enhance STPV efficiency. Selective absorber and emitter for STPV were designed based on w materials.
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S0022407320303356
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Optogalvanic spectroscopy as well as laser induced fluorescence spectroscopy were applied in order to find new energy levels of atomic lanthanum . A hollow cathode lamp and a tuneable continuous wave titanium sapphire laser in the wavelength range from 750nm to 850nm were used for the measurements . Three energy levels of even parity with small values of total angular momentum quantum number
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Further investigation of the hyperfine structure constants of La I levels. Discovery of three new energy levels of even parity 38519.18cm. with. 1 2 40392.80cm. with. 3 2 and 42191.24. with. 3 2. Classification of 21 prviously unknown spectral lines of La I.
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S002240732030337X
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The current study focuses on the radiative characteristics of heavy smoking flames that are formatted by oxygen being added to the fuel stream of a steady laminar ethylene diffusion flame . In such a scenario based on the experimental local soot temperature and volume fraction results the soot local radiative fields are obtained by solving the Radiative Transfer Equation . Along with the diluted range oxygen volume fraction X
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Based on the experimental local soot temperature and volume fraction results the soot local radiative fields are obtained by solving the Radiative Transfer Equation RTE . It is found that the oxygen chemical effect on soot radiative loss promotion is undermined by approximately 25 compared with that on soot formation promotion. In contrast the oxygen dilution effect results in a similar reduction level on soot formation propensity and soot radiative loss. The initial relative oxidation rate at the position of zFv max the peak location of flame cross section mean soot volume fraction and its residence time are two important factors that may affect the final flame smoking non smoking transition.
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S0022407320303411
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We present a comprehensive study on the temperature dependent mid infrared absorption spectra between 8.4m and 11.7m for a complete list of C
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Employed a broad scan rapid tuning EC QCL for the collection of high temperature absorption spectra in a shock tube. Validated the experimental procedure with room temperature nitrogen diluted static spectra measurements at one atmosphere. Reported the absorption spectra for propene 1 butene cis trans 2 butene isobutene and 1 3 butadiene between 8.411.7m and 6001000K. Found good agreement between the measured spectra and absorption predictions from cross section correlations in the literature. Efficiently expanded upon existing spectroscopic knowledge of mid infrared absorption at combustion related conditions.
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S0022407320303459
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We use a recently developed version of the configuration method for open shells to study electronic structure of erbium and fermium atoms . We calculate excitation energies of odd states connected to the even ground state by electric dipole transitions the corresponding transition rates isotope shift hyperfine structure ionization potentials and static scalar polarizabilities . We argue that measuring isotope shift for several transitions can be used to study nuclear deformation in even even nuclei . This is important for testing nuclear theory and for searching for the hypothetical island of stability . Since erbium and fermium have similar electronic structures calculations for erbium serve as a guide to the accuracy of the calculations .
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Calculation of electronic structure and spectroscopic properties of erbium and fermium. Energy levels ionization potentials polarizabilities isotope shift hyperfine structure electric dipole transition amplitudes for Er and Fm. Discussion on the use of hyperfine structure measurements and calculations for the extraction of unknown nuclear moments of Fm. Discussion on the use of isotope shift for the extraction of nuclear parameters of Fm isotopes including nuclear RMS radius and the parameter of nuclear quadrupole deformation. Discussion on the use of calculated isotope shift in the search for hypothetical island of stability.
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S0022407320303460
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Dual view tomographic particle holography combining tomography and holography is a promising approach to yield high accurate 3D measurement of particle field . A standard model of particle hologram has been developed in the framework of generalized Lorenz Mie theory to model and investigate the light scattering effects on three configurations of dual view tomographic particle holography that is dual beam dual view Gabor inline holography single beam dual view combining Gabor inline holography with off axis scattering holography and single beam dual view off axis scattering holography . Dual beam dual view Gabor inline holography is dominated by the traditional Gabor inline hologram but the two light scattering fields bring about small amplitude off axis scattering inline recording hologram negligible self reference hologram and lensless Fourier hologram . The off axis scattering inline recording hologram can produce additional glare points in the reconstructed particle image . The off axis scattering holography reconstructs multiple glare light and generates more than one intersections in the merged 3D reconstructed field in tomographic particle holography leading to possible ghost particle image and implying new algorithm for particle detection to be developed . This model can provide standard hologram to processing algorithm development .
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Three configurations of dual view tomographic holography are investigated. A theoretical model of dual view Gabor inline holography has been developed. The off axis holography can bring glare point on the particle in focus image.
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S0022407320303484
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Ro vibrationally excited molecules of deuterium are involved in non equilibrium chemical reactions in divertor region of tokamak or in neutral beam injector to produce negative ion for fusion plasmas . These molecules produced both in a plasma volume and on surfaces are no longer in their electronic ground state
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Insights into the ro vibrational distribution of D2 molecules are obtained in plasma. The role of the recombinative desorption mechanism is demonstrated. The nature of the plasma facing material modifies the vibrational levels of D2.
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S0022407320303502
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The size dependence of the linear depolarisation ratio of mineral dust aerosols is investigated . Laboratory measurements on 131 different aerosol samples with varying size distributions and mineralogical compositions are fitted with a homogeneous spheroid model . A minimum bias and minimum variance fit of the data is obtained for prolate model particles with a refractive index of 1.525 0.001i and an aspect ratio of 0.87 . The model error is analysed by varying the input parameters to the light scattering computations . It is found that the scattering of the measurements about the model can mainly be explained by variation of the morphology and dielectric properties and to a much lesser extent by variation in the geometric standard deviation of the size distribution . The modelling of the data is extended by using size shape distributions of spheroids . The results indicate that there is some freedom in choosing the best fit weights of the shape distribution of spheroids which could potentially be useful when extending the model to multiple wavelengths or to including additional optical parameters other than depolarisation . However it is also found that the most reasonable fits of the data are obtained by mildly aspherical prolate and oblate spheroids which limits the freedom of adjusting the best fit weights .
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Laboratory measurements of the linear backscatter depolarisation ratio of 131 mineral dust samples are modelled with spheroids. Minimum bias and minimum variance fit of the data shows that mildly aspherical particles best represent the observations. Sensitivity analysis shows that the variation of the data about the mean can be explained by varying the dielectric properties and by random distortions of the geometry.
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S0022407320303563
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The existence of excess surface charges can change the complex refractive index and scattering properties of the submicron single particle . When charged submicron particles constitute a polydisperse particle system the overall optical behavior will be affected by the number of particles size distribution surface charge density and uneven complex refractive index . If the classical Mie theory based on electrically neutral particles is used to analyze such a particle system it will inevitably lead to erroneous results . In this paper the calculation model for scattering properties of charged spherical polydisperse particle systems is established based on Mie theory . Considering the difference in the complex refractive index of the different size particles in the particle system we analyzed the change characteristics of the optical properties of the submicron particle system before and after charged . Through calculation it is found that the non uniform particle size and complex refractive index in the polydisperse particle system have a certain buffer effect on the change of each optical coefficient compared with the monodisperse particle system . Taking different Rosin Ramler distributions as examples we discussed the enhancement effect of surface charges on forward and backward scattering of submicron particle systems . It is found that the enhancement of forward scattering is more effective for particle systems with smaller median diameters . This means that the enhancement of charge helps to achieve visible light measurement of submicron or even nanometer particle systems .
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Establish a scattering properties model of charged polydisperse particle systems. Surface charges can enhance the forward and backward scattering of particle systems. Enhancement effect is related to median diameters and degrees of monodispersity. Polydisperse particles have a buffer to the enhancement effect of charge.
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S0022407320303587
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Measurements of soot black carbon emissions via optical observations of atmospheric plume transmittance require a correction to account for bias in perceived plume brightness due to inscatter of ambient light . The ability to accurately correct for inscattering is hampered however by the potential for multiple scattering within the plume which can not be directly considered without detailed knowledge of the turbulent plume s structure . MS is thus oft ignored within such measurement techniques resulting in an inherent upward bias in calculated emissions . In this work Monte Carlo ray tracing analyses for realistic lines of sight through large eddy simulated soot laden atmospheric plumes of gas flares were used as case study data for analysis of MS effects . Through a reverse MCRT procedure a remarkably simple yet accurate model was derived that relates the quantity of inscattered light under MS conditions to an estimate assuming single scattering . Case study data from previous field measurements of gas flares using the sky LOSA technique demonstrate that neglecting MS effects can bias reported soot emission rates by up to and exceeding one quarter of typical measurement uncertainties . Coupling this model with an additional procedure to correct for minor model biases allows the complex influence of multiple scattering to be directly and accurately considered in optical measurements of soot emissions .
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Optical measurements of soot are complicated by multiple scattering MS effects. Complex MS in turbulent soot laden plumes can be captured by a simple MS model. MS model permits use of single scattering assumption in radiative transfer analyses. Sky LOSA case studies show value of MS model in correcting bias due to MS.
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S0022407320303599
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In this paper we derive the transition matrix of a nonspherical layered particle consisting in a dielectric core and a metallic shell in the non local optical response theory . The key point in our analysis is the separation of the internal field within the shell into a transverse and a longitudinal field . The approach uses the null field equations for the total field inside the particle and the transverse and longitudinal fields outside the metallic shell the integral representation for the scattered field the conventional boundary conditions for the transverse fields and the additional boundary conditions for the normal components of the fields . Depending on the way in which the additional boundary conditions are treated three methods for computing the transition matrix are proposed . When the non local effects are neglected the transition matrix becomes the transition matrix in the local optical response theory and for a homogeneous particle the transition matrix simplifies to that derived in a previous paper .
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The transition matrix of a nonspherical layered particle consisting in a dielectric core and a metallic shell in the non local optical response theory has been derived. Depending on the way in which the additional boundary conditions are treated three methods for computing the transition matrix have been proposed. We demonstrate that when the non local effects are neglected the transition matrix becomes the transition matrix of a layered particle in the local optical response theory.
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S0022407320303605
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The optical properties of non spherical particles have been studied for decades and there are a number of solution techniques to model distinct geometries . Of these methods the Discrete Dipole Approximation is known to compute electromagnetic scattering from irregularly shaped heterogeneous particles . DDSCAT which is the numerical implementation of DDA is identified as a potential solver for electrically charged particles however there is a set of limitations and shortcomings to be addressed . The main concern is the conductivity which introduces an infinitesimally thin charged monolayer on the particle surface . The side effect of this concept is a steep increase of refractive index and impedance . The DDSCAT can have trouble converging to a solution when the thin shell at the particle surface produces large losses due to having electromagnetic properties significantly different from the media on either side of the particle interface .
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Optical properties of nonspherical charged particles are computed using DDA. The modeling is at wavelengths where charge induced resonances typically occur. Surface charge distribution is simulated by a multi level material distribution. The method is validated for a pseudosphere which allows for an analytical solution. The method takes advantage of the interfaces to DDSCAT.
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S0022407320303629
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The integro differential radiative transfer equation for concentric cylinders problem involving scattering absorption and emission is solved using the discontinuous Galerkin finite element method . The space angle DG method directly solves the cylindrically symmetric RTE as a three dimensional problem where a 1D spatially domain in radial distance
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Discontinuous Galerkin Method DGM for solving radiative transfer equation RTE . DGM employed in both space and angles is superior to hybrid methods. Convergence in polynomial order and mesh refinement is established. Comparison with benchmark results shows good agreement. Numerical examples show how DGM captures discontinuous solutions.
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S0022407320303678
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As the 2020 winner of the van de Hulst Award I have been committed to the writing of a van de Hulst Essay which is presented here . The Award has been essentially motivated by my work on laser light scattering by particles which spreads over 40 years . During this time I may have obtained several results of interest but some of them made me feeling this kind of extraordinary shocks both emotional and psychological to which it is only possible to react by a booming Wow . Therefore beside a review on my work on light scattering the heart of the present paper is devoted to 4 wow stories related to the development of generalized Lorenz Mie theories . They concern the optical theorem the speed of laser light slower than
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Review on the development of generalized Lorenz Mie theories. Optical theorem and structured shaped beams. Speed of light and nature of photons regarding particular effects. Epistemological discussion on the underdetermination thesis of theories by experiments.
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S002240732030368X
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A plane electromagnetic wave amplitude and frequency modulated as a linear chirp is incident on a dielectric sphere that hosts an eccentric spherical pec inclusion . This radiation problem is solved in the frequency domain by use of symmetry dependent spherical eigenvectors the end result being a set of linear equations for the wave amplitudes of the frequency spectrum of the electric field in every part of space . That set is solved by truncation and matrix inversion separately for even and odd symmetry wave amplitudes . The backscattered chirp is found by an inverse Fourier transform that yields the time dependent monostatic radar cross section . A numerical application manifests the possibility to detect a pec sphere concealed in an acrylic sphere by use of a wide band chirp that targets a morphology dependent resonance of the composite body . Our theory and code are validated by use of a commercial software .
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The radiation problem is solved in the frequency domain by use of symmetry dependent spherical eigenvectors and indirect mode matching equations. The time domain backscattered chirp is obtained by use of the Fourier transform. The envelope of the backscattered chirp acquires the shape of the morphology dependent resonance targeted by the incident chirp. The numerical example indicates that a metallic inclusion placed anywhere within the host can be detected by proper design of the incident chirp.
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S0022407320303721
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There has been an increased interest on the development of infrared radiation regulation based on microstructured surfaces with desired radiative properties . Here design of a microstructured surface is proposed in terms of structural combinations to mediate the IR characteristics of targets . The designed microstructured surface is a combined structure which is a two dimension periodic composite grating obtained by combining two periodic simple gratings with different parameters and taking the union . Remarkably the simple grating is also a combined structure obtained by combining and taking the intersection of two different single structures a dielectric metal dielectric structure and a metal grating structure . The results show that on the premise of having the structural characteristics of both constituent structures the designed combined structures can not only inherit the spectral characteristics of both constituent structures but also have some new effects . For the adjusted composite grating it is found that three absorption peaks with the maximal absorbance up to 89 are achieved in 58m range . Additionally the average reflectance is greater than 80 in 35m and 814m bands . The adjusted composite grating fulfills the requirement for multiband regulation and the method of structural combinations suggests a feasible means to regulate the IR characteristics of targets .
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A microstructured surface based on structural combinations to mediate IR features. On the premise of having the structural features of both constituent structures. Combined structures inherit the spectral features of both constituent structures. Combined structures can also have some new effects. Adjusted composite grating fulfills stringent requirements for infrared stealth.
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S0022407320303836
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Considerable work has gone into identifying and delineating the effects of quantum monodromy on molecules . Recently this included consideration of transition intensities of the NCNCS molecule using
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HOCl absolute transition intensities calculated with GSRB agree with HITRAN database. GSRB spectra obtained using. dipole moment function in corrected program. With one exception the calculated spectra of NCNCS now agree with experiment. The calculated and observed. type rovibrational transitions of NCNCS do not agree. Possible explanations of this disagreement are considered.
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S0022407320303873
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The partition function of a molecule can be obtained by a direct sum over states calculation using the molecules quantum energy levels . These energies can be those obtained by a model fitted to experimental data . For molecules with exotic behaviour physically motivated models can be required . Often however such models can be limited in the range of quantum levels that can be reliably calculated making a converged SOS calculation impractical . Here we present a hybrid approach for prolate top molecules . Our hybrid approach allows the simple extension from a limited SOS calculation to a good approximation for the infinite sum limit . This is achieved by adding easily calculated closed form corrections to the limited SOS result . We test our approach using the Generalised SemiRigid Bender program as the physically motivated model . HOCl serves as a good test case because for it the GSRB model can extend to high enough levels for convergence of the direct SOS calculation . Then by limiting the range of GSRB calculated rotational levels included in the SOS we confirm our hybrid approach . The technique we present here should be particularly applicable to quasilinear molecules including those exhibiting quantum monodromy . The Appendix presents step by step instructions for implementing this hybrid procedure . Also presented there is a brief discussion of how to adapt the hybrid technique to approximately account for rotational or vibrational dissociation in the case that that is necessary .
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We present an accelerated technique for calculating the molecular partition function. The technique combines a limited sum over states calculation with a correction term. The accuracy of this hybrid technique is validated by application to HOCl. Convergence is much faster than with a pure sum over states SOS calculation. The technique is applicable to prolate top molecules including quasilinear ones.
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S0022407320303964
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The Invariant Imbedding T matrix method has been recognized as one of the most promising method to derive exact solution of the light scattering properties of the nonspherical atmospheric particles after the significant improvement by Bi L. and Yang P. Compared with DDA and the time domain methods it can calculate the scattering properties of the random oriented particles analytically once the T matrix of the particle is obtained . In order to better understand the modeling capability of this model and optimize the parameter settings for the particles with different geometrical and optical properties the factors influencing the modeling accuracy are systematically analyzed which includes the discretization schemes of the radial integral the discrete point numbers of the radial zenith and azimuthal integrals . The results show that the calculation accuracy of Gaussian quadrature technique is higher than that of the trapezoidal rule in the radial discretization . For particles with large size parameter or refractive index the density of the discrete points should be increased correspondingly to ensure the calculation accuracy . Finer discrete grids are also required for particles with extreme shapes . Based on the analysis above the method to determine the parameters of scattering simulation is further proposed for particles with different geometrical and optical properties by which the discretization of the computational domain can be optimized once the refractive index and geometry of the particle are known . The method is also validated for cylinders and hexagonal prisms the results shows that the optimization scheme can be applicable to particles with different shapes .
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The influence of the radial discretization on calculation accuracy of the invariant imbedding T matrix method is investigated. The influence of the discretization of the zenith and azimuthal integrals on the modeling accuracy is systematically analyzed. The optimal design of the discretization scheme of the nonspherical particles is proposed particles with different geometrical and optical properties.
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S0022407320303976
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While most of traditional Earth atmosphere satellite remote sensing relies on radiative transfer in the plane parallel geometry effects of sphericity are important at high sun and view zenith angles . Broad understanding of these effects is limited and contrary to the plane parallel case finding accurate numerical results to test spherical RT codes is not easy . This paper aims to partially fill in this gap . Using the full spherical RT code MYSTIC and the plane parallel RT code VLIDORT corrected for atmospheric sphericity in the single and multiple scattering we reproduced with better accuracy and extended the benchmark results by
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Accurate numerical results to test spherical RT codes are hard to find in literature. We reproduced with better accuracy the results by Adams and Kattawar. We used RT codes MYSTIC Monte Carlo true spherical atmosphere and VLIDORT discrete ordinates corrected for the effect of spherical atmosphere . We extended the results by A K for relative azimuth other than 0180 principal plane . Results of our simulation are reported in numerical format.
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S002240732030399X
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Gm APD is widely used in the LIDAR for its excellent photon detection capability . However the low SNR limits the laser echo s triggering probability and enhances the false alarm probability in the daytime which severely affects the target s detection results moreover it increases the difficulty of the signal reconstruction algorithm . So it s an important path to relieve the algorithm s burden and get a better detection results by fundamentally increasing the echo s SNR . Nevertheless there is a lack of researches discussing such issue especially for array imaging detection . In this paper it was proposed that by using the polarization detection could help to enhance the echo s SNR and get good detection results in the daytime . By combining polarization bi directional reflection distribution function Mueller matrix LIDAR equation and Poisson models the polarization Gm APD LIDAR detection model was first established to describe the received Stokes vector as well as the triggering and false alarm probabilities which could aid in the daytime polarization detection including polarization analysis depolarization contrast analysis detection probabilities analysis and the feasibility of the models was supported by the simulation and experimental results . Based on the established model the triggering properties of the Gm APD LIDAR with the polarization system were discussed and the theoretical analysis showed that the optimal detection angle was 135 at which the polarization detection could effectively increase the triggering probability and lower the false alarm probability . A series of outdoor experimental verifications were carried out and the experimental results showed that the proposed Gm APD polarization detection model and the theoretical analysis were absolutely correct . Besides compared with the non polarization detection the intensity image of optimal polarization detection could completely obtain the targets contour moreover the triggering probabilities of two targets increased by 4.9 and 7.1 respectively and the false alarm probabilities lowered by 26.3 and 21.4 . It made great improvement in the Gm APD detection research . This work offers the theoretical and experimental supports for enhancing Gm APD LIDAR s detection results in the daytime by using polarization detection furthermore it can lay some theoretical foundations for target recognition of Gm APD polarization detection .
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Polarization detection is first implemented in the Gm APD LIDAR. The polarization Gm APD LIDAR ranging equation is first proposed. The proposed polarization Gm APD detection model fits the experiment data well. The polarization detection can efficiently enhance the Gm APD detection results in the daytime.
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S0022407320304052
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The hyperfine structure of 15 spectral lines of the manganese atom was investigated with the method of laser induced fluorescence on an atomic beam . Results of these investigations supplemented by the results obtained in Part I of this work series yielded the hyperfine structure constants
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Hyperfine structure hfs of 15 spectral lines in atomic manganese was recorded by laser induced fluorescence on an atomic beam. Results of these investigations supplemented with the data obtained in the previous work Part I of the series yielded the hyperfine structure constants A and B for 38 upper odd parity levels. For 11 odd parity levels both hyperfine structure constants A and B were determined for the first time for another 10 levels new constants B were evaluated for the remaining 17 levels the hfs constants were revised. Semi empirical analysis of the odd parity level system in Mn I was performed in a basis of 35 configurations. Fairly good consistency was found between the experimental hfs constants and those predicted in the semi empirical fit.
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S0022407320304064
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We report results of a theoretical analysis of hyperfine interactions in the HD molecule . We present the calculated coupling constants spin rotation spin spin and electric quadrupole coupling constants for all bound states of HD in its ground electronic
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Analysis of the hyperfine structure of all rovibrational states of the HD molecule. Calculations of the hyperfine coupling constants for all rovibrational states of the HD molecule. List of positions and intensities of 108 320 hyperfine components of 5 129 dipole transitions from the P and R branches.
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S0022407320304301
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This study deals with the analysis of the propagation of thermal radiation within absorbing and scattering composite materials with rough boundaries . The two phase system is treated as an equivalent homogeneous medium characterized by volumetric radiative properties namely extinction coefficient scattering albedo and phase function whereas the interaction of the radiation with the medium boundaries is modeled with boundary scattering properties . The aim is to determine these volumetric and boundary scattering properties by an inverse analysis for parameter identification . It consists of minimizing the sum of the squared difference between calculated and measured bidirectional and normal hemispherical reflectances and transmittances . The Gauss Newton algorithm is employed for solving this nonlinear least squares problem . The experimental data are obtained by using a visible and near infrared spectrophotometer equipped with a goniometric system enabling measurements in different scattering directions around a sample between 0.4 and 2.5m . The collision based Monte Carlo method is employed to assess the theoretical values by solving the Radiative Transfer Equation along with boundary conditions designed for samples with rough surfaces . The proposed approach is proved to be well appropriate for determining the radiative properties of the rough composite samples . More interestingly this study demonstrates that the scattering phase function can be modeled by the Henyey and Greenstein approximation and the boundary scattering distributions can be modeled by a Gaussian function and or a cosine function .
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Radiative transfer from UV to near IR in glassfiber epoxy composite media are investigated. Surface roughness has a major impact on the scattering behaviour of these materials. Bidirectional responses of rough samples are obtained with a new Monte Carlo method. Volumetric and surface scattering properties are simultaneously determined by inverse method.
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S0022407320304350
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The planetary boundary layer height is a primary parameter characterizing the boundary layer and its accurate estimation is critical . The wavelet covariance transform method is a common inversion algorithm of the PBLH estimation but is subject to the problems of dilation selection and interference from clouds aerosols etc . An improved method combining the whale optimization algorithm and the top limit is proposed to overcome these difficulties and realize the automatic determination of PBLH . In particular the dilation obtained by WOA can be more accurate to several decimal places compared to the frequently used empirical integers . The proposed method is tested on different simulation and real cases and compared with radiosonde measurements . The results show that the improved method is accurate effective and stable for automatic retrieval of PBLH based only on simple micropulse lidar without the aid of other measurements .
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A novel method of dilation determination is proposed which is more accurate to several decimal places compared to the frequently used empirical integers. Top limit is verified to be effective in reducing the interference of the cloud layer residual layer etc. The improved method is accurate effective and stable for automatic retrieval of PBLH based only on simple micropulse lidar MPL without the aid of other measurements. This work overcomes the main problems of wavelet covariance transform WCT method and is beneficial to the popularization and application of the WCT method.
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S0022407320304362
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Dyadic Green s function for a multilayered spherical structure with alternating graphene dielectric shells is extracted in this paper . To this end the unknown expansion coefficients of the scattering superposition method are obtained by considering graphene local surface currents at the interface of two adjacent layers . To validate the formulas the procedure of Mie scattering analysis employing our formulas is clarified and the extinction efficiencies of various graphene based nanoparticles are computed . The possibility of using the proposed structure in the design of multi band optical absorbers is discussed in detail . Moreover a closed form formula for obtaining the Purcell factor of a radial dipole emitter in the presence of a graphene based layered sphere is introduced . The analysis is followed by an example illustrating the possibility of dual band enhancement of the Purcell factor using a graphene based core shell particle . Finally the procedure of calculating the energy transfer between the donor acceptor pairs with arbitrary locations are clarified . The research can be potentially used in the fast and efficient analysis of a wide class of novel optical devices with the arbitrary source of excitation .
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The scattering analysis of graphene based multilayered spherical structures is extended for the analysis of arbitrary sources by introducing some extra expansion coefficients thus calculating corresponding Green s function. The procedure of Mie analysis as a special case of Green s function analysis is proved and multiband absorber design is discussed as the application. The effect of the interlayer permittivity on the optical response is disclosed in detail. Purcell factor calculation using the extracted Green s function is discussed as another instance. In this case the field and source points coincide. Energy transfer between donor acceptor pairs of arbitrary locations can also be analyzed with the introduced unified formulas.
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S0022407320304490
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Due to attractive candidate for the laser application and searching for the permanent electric dipole moment of the electron mercury bromide is of much interest to researchers . However detailed information of the electronic structure of HgBr is still lacking especially for spin orbit interactions in excited states . In this work high level configuration interaction calculations of low lying states correlating to the lowest two dissociation limits Hg
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The potential energies of 14 S states of HgBr are calculated by MRCI method. The spin orbit coupling and 5d. correlation effects are included in the calculation. Spectroscopic constants of bound states of HgBr are determined. The predissociation mechanism of C. None. of HgBr are analyzed. Radiative lifetimes of C. None. D. None. and B. None. states of HgBr are evaluated.
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S002240732030457X
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In this work we performed spin orbit coupling included MRCI Q calculation on electronic states of SbBr . The SOC effect is treated by using the state interaction method in combination with the Breit Pauli operator . Molecular orbitals are constructed with all electron aug cc pwCVQZ DK basis sets . Without SOC total 34 S states of SbBr are obtained . It is found that the lowest three S states X
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Total 34 S states of SbBr are accurately characterized at the MRCI Q level. The SOC effect makes 34 S states split into 74 states. Transition mechanisms of a. X. None. and b. None. X. None. are illustrated. The SOC effect is indispensible for accurate spectroscopic determinations of SbBr.
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S0022407320304581
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Light pollution generated by the excessive use of artificial light at night is an environmental and ecological concern . Artificial light at night is diffused far from the sources for long distances by scattering in the atmosphere thus affecting the night sky and the biodiversity of rural and natural areas . The characterization of the level and variability of light pollution has become an important issue for several disciplines .
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NSB in Tuscany ranged between 17.2 83 times brighter than the natural background and 21.5 mpsas during moonless night. Seasonal NSB during moonless night presented a different pattern in wet and dry season at urban sites. NSB was affected by monthly cycle of moonlight and its effect interacted with weather conditions. Average night sky during precipitation events was approximately six times 2 mpsas than during dry days. The presented analysis might be applied in ecological studies regarding light pollution effects on the environment.
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S002240732030474X
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Rayleigh scattering cross sections for argon carbon dioxide sulfur hexafluoride and methane were measured using Broadband Cavity Enhanced Spectroscopy between 264 and 297nm extending the region of experimental cross section data available for all four gases . The experimentally derived values for Ar and CO
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Rayleigh scattering cross sections measured for gases from 264 to 297nm with BBCES. Results for Ar and CO. in excellent agreement with refractive index based values. Measured cross sections for SF. and CH. disagree with previous n based values. New dispersion formulas are derived for SF. and CH. for use in the UV and visible. New cross sections provide accurate reference values for BBCES mirror calibration.
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S0022407320304866
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Monte Carlo ray tracing methods are important for solving the radiative transfer equation . However the particular ray tracing procedure used has a significant impact on the calculational performance . In this paper we analyze and compare the performances of MCRT pathlength and collision based methods for different surface and medium parameters and different degrees of uniformity . The results show that in a gray medium and with a radiation heat balance system the PL method is superior when the surface emissivity is less than 0.15 for surface elements and when the mean optical thickness per element is small and the emissivity is large for space elements otherwise the CB method is superior . Also the overall performance of the PL method is better than that of the CB method . However PL method is more sensitive to non uniformity of medium parameters than the CB method and that the PL method is more sensitive to uniformity of the scattering coefficient than to the absorption coefficient . In addition for a gray body and uniform optical parameters reducing the number of grids improves the performance of the MCRT . And the performance index of the PL method is the best when the cutoff level of energy beam tracking is 10
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Advantage ranges of the surface and space parameters for pathlength and collision based methods are obtained respectively. The pathlength method is more sensitive to non uniformity of medium parameters than the collision based method. The pathlength method is more sensitive to uniformity of the scattering coefficient than to the absorption coefficient. The performance index of the pathlength method is the best when the cutoff level of energy beam tracking is 10. and 10. for surface and space elements respectively. The overall advantage of path length method is greater than that of collision method.
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