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title: Nanoscale polarization relaxation kinetics in polycrystalline ferroelectric thin films; abstract: We report on the nanoscale kinetics of ferroelectric domain wall motion in polycrystalline ferroelectric thin films. High-resolution piezoresponse force microscopy is employed to investigate the changes that occur at the domain wall surface during the polarization relaxation process. 50×50nm2 domain images reveal that domain wall motion is a very jerky process. The domain wall motion shows two distinct cycles—one where it breaks into several segments to advance, following which it recombines to form a continuous surface. This “pinning-depinning” cycle continues throughout the relaxation process. A kinetic model based on the concept of domain wall mobility and a thermodynamic driving force is developed to explain this jagged motion. | 161,600 |
title: Magnetic Studies of Ion Beam Irradiated Co/CoO Thin Films; abstract: Abstract Ion beam irradiation was performed on Co/CoO films deposited on Si (111) substrates by magnetron sputtering. Ion-beam-induced dewetting was observed. Dewetting is due to larger surface free energy of Co compared to CoO. Magnetic studies performed by SQUID and PPMS, showed exchange bias at the Co/CoO interface which forms a FM/AFM system. | 161,601 |
title: Cosmic-ray-produced electrons and gamma rays in the atmosphere; abstract: The propagation of the primary cosmic radiation through the earth\u0027s atmosphere is a phenomenon of considerable intrinsic complexity stemming from the large number and variety of parameters involved and their dependence on energy, latitude, and atmospheric depth. Although in the past the study of the hadronic component in the atmosphere has received appreciable attention, not much interest has been focused on the electron-photon component until very recent years. As a consequence, the observational data now available on the latter are meager and fragmentary; such information as is available is reviewed here, and the existing gaps in our knowledge are highlighted. Because of the very complexity of the problem, it has been recognized that extensive and refined calculations are needed to understand the observations and to provide new motivation to experimenters. In the present article the limited theoretical calculations so far attempted are first reviewed; a summary of detailed calculations recently carried out by the present authors follows. Finally, the results from the calculations are compared with those available from experiments; wherever it is necessary, attempts are made to identify the areas in which further work is needed. | 161,602 |
title: Nonlinear stress-strain behavior and stress-induced phase transitions in soft Pb(Zr 1-x Ti x )O 3 at the morphotropic phase boundary; abstract: Temperature-dependent stress-strain behavior of various soft Pb0.98Ba0.01(Zr1−xTix)0.98Nb0.02O3, 0.40≤x≤0.60, compositions was characterized between 25 and 400 °C to determine the influence of crystal structure on ferroelasticity. The ferroelastic response was found to depend significantly on the crystal phase as well as the spontaneous strain, both of which varied with temperature. The remanent strain for rhombohedral materials was shown to be above the theoretical maximum allowed by the crystal spontaneous strain. This observed behavior indicates the presence of hysteretic processes in addition to ferroelasticity during mechanical compression. A phenomenological free energy analysis was used to predict the effects of stress on the stable phase in ferroelectrics and indicates the susceptibility of the rhombohedral and tetragonal structure to a stress-induced phase transition. Modeling results indicate the relative importance of such phase transitions on macroscopic stress-strain behavior, giving an indirect method to observe field-induced phase transitions in polycrystalline ferroelectrics. | 161,603 |
title: Analysis of magnetic interactions in rare-earth-doped crystals for quantum manipulation; abstract: The influence of magnetic interactions in rare-earth-doped crystals under an external magnetic field has been studied in order to obtain an efficient three-level $\\ensuremath{\\Lambda}$ system with the hyperfine levels of the rare earth. Nuclear Zeeman effect under the action of an external magnetic field removes the nuclear degeneracy. This interaction does not provide an efficient $\\ensuremath{\\Lambda}$ system because nuclear-spin flipping such as $\\ensuremath{\\mid}{M}_{I}⟩=\\ifmmode\\pm\\else\\textpm\\fi{}\\frac{1}{2}\\ensuremath{\\rightarrow}\\ensuremath{\\mid}{M}_{I}⟩=\\ensuremath{\\mp}\\frac{1}{2}$ (${M}_{I}$ is the nuclear-spin projection) cannot be induced by an optical transition. However, this selection rule only applies to pure nuclear Zeeman effect. Indeed, it is shown that the coupling of the electronic Zeeman and of the hyperfine interactions releases the nuclear-spin selection rules $\\ensuremath{\\Delta}{M}_{I}=0$. This can be described in terms of a pseudonuclear Zeeman effect induced by an effective magnetic field. The relative strengths of the two optical transitions involved in the three-level system can be controlled by the orientation of the external magnetic field. The particular case of the ${\\mathrm{Tm}}^{3+}$ ion in the ${\\mathrm{Y}}_{3}{\\mathrm{Al}}_{5}{\\mathrm{O}}_{12}$ host (YAG) is discussed. ${\\mathrm{Tm}}^{3+}$ hyperfine structure is determined using a complete Hamiltonian including free-ion, crystal-field, and magnetic interactions. A good three-level $\\ensuremath{\\Lambda}$ system is obtained in Tm:YAG with a transition strength ratio of 0.24 $(\\ensuremath{\\sim}1:4)$ between the two optical transitions. An analytical analysis based on a spin-Hamiltonian approach is proposed to explain the results of the complete crystal-field calculations. Finally, an experimental protocol that makes a crystal similar to the atomic samples used in previous quantum information investigations, with the additional benefits of absence of motion and long coherence time, is described. | 161,604 |
title: Coherent control of optical gain from electronic intersubband transitions in semiconductors; abstract: We study electronic transitions between a subband and a lower subband doublet which is driven by a coherent microwave (MW) field in a semiconductor double well structure. Within a microscopic three-band model, we show that variation of the MW phase allows manipulation of the optical gain provided the probe pulse duration is shorter than the period of the MW-field-generated interband polarization in the doublet. Moreover, we find that optical gain without inversion can be achieved in spite of subpicosecond dissipative mechanisms provided by electron-phonon coupling and electron tunneling into and out of the double well. | 161,605 |
title: Can Mass of the Lightest Family Gauge Boson be of the Order of TeV; abstract: The observed sign of a deviation from the e-µ universality in tau decays suggests family gauge bosons with an inverted mass hierarchy. Under the constraints from the observed K 0 - ¯ K 0 and D 0 - ¯ D 0 mixing, we investigate a possibility that a mass M33 of the lightest gauge boson A 3 which couples with only the third generation quarks and leptons is of the order of TeV. It is concluded that M33 ∼ 1 TeV is possible if we adopt a specific model phenomenologically. | 161,606 |
title: Influence of additives on the properties of a Ni–Zn ferrite with low Curie point; abstract: We investigated the effects of four additives (Sb 2 O 3 , Na 2 O. CaO and ZrO 2 ) on the properties of Ni 0.255 Zn 0.745 Fe 2 O 4 ferrite, having Curie point around 0°C. Na 2 O and Sb 2 O 3 favour the densification of the ferrite at low temperature, but increase T c . CaO improves the density and decreases T c . All additives improve the temperature dependence of μ i and the electrical resistivity. The best additive seems to be CaO which accomplishes the best compromise with respect to the density, electrical resitivity and the shape of μ i -T curve. | 161,607 |
title: On the L-M-N multiple ionisation in heavy elements; abstract: The L X-ray spectra of Au and Th have been measured in collisions with C, F, Mg, Si, S and Cu ions in the energy range 0.5-2.5 MeV amu-1. From the shifts of the yield ratios and energies of the L/sub // , Lalpha , Leta and Ly1 lines relative to those for 2.5 MeV proton bombardment, the average numbers of M4.5 (and N4) vacancies present during the L-vacancy decay have been determined. The corresponding outer-shell ionisation probabilities show remarkable agreement with the geometrical model of Sulik et al. (1985) except for the Cu projectile. | 161,608 |
title: Structural instability of the CoO4 tetrahedral chain in SrCoO3−δ thin films; abstract: Raman scattering experiments together with detailed lattice dynamic calculations are performed to elucidate crystallographic and electronic peculiarities of SrCoO3−δ films. We observe that the 85 cm−1 phonon mode involving the rotation of a CoO4 tetrahedron undergoes a huge hardening by 21 cm−1 with decreasing temperature. In addition, new phonon modes appear at 651.5 and 697.6 cm−1. The latter modes are attributed to the Jahn-Teller activated modes. Upon cooling from room temperature, all phonons exhibit an exponential-like increase of intensity with a characteristic energy of about 103–107 K. We attribute this phenomenon to an instability of the CoO4 tetrahedral chain structure, which constitutes a key ingredient to understand the electronic and structural properties of the brownmillerite SrCoO2.5. | 161,609 |
title: Superburst with Outburst from EXO 1745-248 in Terzan 5 with MAXI; abstract: MAXI/GSC detected a superburst from EXO 1745-248 in the globular cluster Terzan 5 on 2011 October 24. The GSC light curve shows an exponential decay with an e-folding time of 0.3 day. The spectra are consistent with the blackbody radiation, whose temperature is 2.2 keV and 1.2 keV at MJD 55858.56 and 55859.20, respectively. The fluence is $1.4 \\times 10^{42}$ erg in 2-20 keV assuming 8.7 kpc distance. The sphere radius of the blackbody and its luminosity are estimated to be 6.2 km and $1.1 \\times 10^{38}$ erg s$^{-1}$, respectively, from the spectral fitting at the flux peak. Those e-folding time, temperature, softening, fluence, and radius are typical of superbursts from the low-mass X-ray binaries. The superburst was followed by an outburst 28 hours after the superburst onset. The outburst lasted for 5 days and the fluence was $4.3 \\times 10^{42}$ erg. The instability of the accretion disk caused by the superburst would be an explanation for the outburst, whereas the mass accretion of the matter evaporated from surface of the companion star by the superburst would be another possibility. | 161,610 |
title: Rayleigh–Bénard convection driven by a long wavelength heating; abstract: Natural convection in a two-dimensional horizontal layer has been investigated. The layer is confined between two parallel horizontal plates. The upper plate is kept isothermal, while the lower plate has an externally imposed, long wavelength, spatially sinusoidal heating with the amplitude expressed in terms of the Rayleigh number Ra and the wavelength characterized by the wave number α. Only steady-state flow structures and their bifurcations have been considered. The detailed analysis has been carried out for two Prandtl numbers, i.e. Pr = 0.7 and Pr = 7, and only small differences in the bifurcation diagrams have been observed. When Ra 427. When 427 ∼470 and α \u003e ~0.14, bifurcation assumes the form of “bifurcation from infinity”. The main branch is associated with one pair of rolls per heating period for α \u003e 0.25. Decrease in α along this branch results in the formation of secondary rolls, with the rolls at the hot spot co-rotating with the primary rolls. The lower part of the other branch is associated with one pair of rolls per heating period in the limit α → 0. Increase in α results in pinching off a single roll which counter-rotates with respect to the primary roll at the hot spot. | 161,611 |
title: Active and passive scalar intermittent statistics in turbulent atmospheric convection; abstract: a b s t r a c t We study the small-scale statistics of active and passive scalar fields, obtained from 3D largeeddy simulations of the atmospheric boundary layer turbulence. The velocity field is anisotropic and inhomogeneous, due to the action of both buoyancy and shear. We focus on scalar field rare fluctuations dominated by the so-called fronts. Temperature, coupled to the velocity field by the Boussinesq equations, exhibits anomalous scaling and saturation of the scaling exponents to a constant value, due to the presence of thermal fronts. Although qualitatively similar, the small-scale statistics of a passive tracer advected by the convective flow shows quantitative differences: the large fluctuations of the tracer concentration field distribute differently and appear to be less intermittent than the temperature ones. To better understand these results, the role of boundaries in this problem is discussed. | 161,612 |
title: Absorption of electromagnetic and gravitational waves by Kerr black holes; abstract: Abstract We calculate the absorption cross section for planar waves incident upon Kerr black holes, and present a unified picture for scalar, electromagnetic and gravitational waves. We highlight the spin-helicity effect that arises from a coupling between the rotation of the black hole and the helicity of a circularly-polarized wave. For the case of on-axis incidence, we introduce an extended ‘sinc approximation’ to quantify the spin-helicity effect in the strong-field regime. | 161,613 |
title: Experimental study of temperature fluctuations in forced stably stratified turbulent flows; abstract: We study experimentally temperature fluctuations in stably stratified forced turbulence in air flow. In the experiments with an imposed vertical temperature gradient, the turbulence is produced by two oscillating grids located nearby the side walls of the chamber. Particle image velocimetry is used to determine the turbulent and mean velocity fields, and a specially designed temperature probe with sensitive thermocouples is employed to measure the temperature field. We found that the ratio (� x ∇xT) 2 + (� y∇yT) 2 + (� z∇zT) 2 /� θ 2 � is nearly constant, is independent of the frequency of the grid oscillations, and has the same magnitude for both, stably and | 161,614 |
title: Superfluidity in neutron stars; abstract: Possible states of superfluidity in the liquid interiors of neutron stars, including neutron pairing, proton pairing and pion condensation are described, and recent work on the subject is reviewed. | 161,615 |
title: Conventional and photothermally modulated ferromagnetic resonance investigations of a Nd2Fe17 powder sample; abstract: Abstract We report ferromagnetic resonance (FMR) and photothermally modulated ferromagnetic resonance (PM-FMR) results for the ferromagnetic alloy Nd2Fe17. Calculations for the ferromagnetic resonance signal with the magnetization in the non-saturated regime are presented. A theoretical model to describe the FMR and PM-FMR spectra of this material in the form of a non-oriented pressed powder is discussed and fair agreement between experimental and calculated spectra is obtained. Our own numerical values of magnetization obtained over a wide temperature range are used for the PM-FMR signal calculation as well as resonance field and linewidth from our FMR experiments. | 161,616 |
title: Effect of Sn doping on the martensitic and premartensitic transitions in Ni2MnGa; abstract: Abstract The effect of Sn doping at the Ga site of Ni2MnGa is investigated through magnetic and magneto-transport measurements. Clear signatures of martensitic and premartensitic transitions are observed in the pure as well as in 5% Sn doped alloy. For 10% Sn doping, the martensitic transition vanishes, while the premartensitic transition remains visible at low temperature. All the samples are found to have a ferromagnetic ground state with saturation moment decreasing with increasing Sn concentration. The magnetocaloric effect near the martensitic transition in the pure and 5% Sn doped samples is found to be positive. However, the entropy change is found to decrease with increasing magnetic field, which is particularly prominent in the undoped sample. The samples also show negative magnetoresistance with anomalies at the martensitic and premartensitic transition points. | 161,617 |
title: Anomalous magnetoconductivity of epitaxial Nd0.7Sr0.3MnO3 and Pr0.7Sr0.3MnO3 films; abstract: Abstract In Nd 0.7 Sr 0.3 MnO 3 films, ranging in peak resistivity from 1000 Ω·cm to ≤1 Ω·cm, and exhibiting large magnetoresistance effects, the zero-field resistivity above the peak temperature T p exhibits thermally activated behavior with an activation energy of 0.115±0.005 eV. At T well below T p , the magnetoconductivity, rather than the magnetoresistance, is linear in B and this linear dependence is observed over a wide B range even when the magnetization is essentially saturated. A cross-over from the linear relation to σ increasing as B 2 is observed near and above T p . A tentative model is proposed. | 161,618 |
title: On the stability of continuously stratified quasi-geostrophic hetons; abstract: In this paper we examine the stability of quasi-geostrophic hetons in a stably, continuously stratified fluid. To this purpose we first determinate numerically equilibrium states. Equilibrium hetons consist of two vortices of equal and opposite strength lying at different depths that are steadily translating without deforming. The situation is studied through a parameter space comprising of the vertical offset between the vortices, their horizontal separation distance and their aspect ratio. The study first shows that the equilibrium vortices are not only strongly deformed in the vertical but that their instability modes are also varying within the height of the structures. The main purpose of the present contribution is to study families of equilibria which stem from the case of two vertically aligned cylindrical vortices. It is however shown that other branches of solutions exist with different properties. The paper concludes that hetons may be sensitive to baroclinic instabilities provided the separation distance between the poles of the hetons is moderate both in the horizontal and in the vertical directions. The hetons become stable and efficient ways to transport properties as far as the poles are distant from one another. The critical separation distance in a non-trivial function of the radius-to-height aspect ratio of the poles. | 161,619 |
title: CdTe/HgCdTe indium-diffused photodiodes; abstract: Abstract CdTe/HgCdTe structures have been prepared by MBE deposition of high resistivity CdTe on bulk p -type Hg 1− x Cd x Te ( x = 0.295). Diodes were produced by diffusion from indium dots evaporated on the CdTe surface. The I-V characteristics are diffusion-limited down to a temperature of 160K. The C-V characteristics indicate a built-in potential of 0.2 V. The diodes operate as photovoltaic detectors due to lateral collection around the diffused region, showing a spectral response between 0.9 and 5 μm. The lateral collection effect has been used to measure the minority carrier diffusion length in the HgCdTe substrate and calculate the theoretical saturation current as a function of temperature; good agreement with the experiment was found. | 161,620 |
title: Thermal, Fluid Flow, and Tritium Release Problems in Fusion Blankets; abstract: AbstractThe thermal, fluid flow, and tritium release problems represent a major part of the research and development issues for liquid-metal and solid breeder blankets. The issues are characterized, and recent progress in model development and experiments is described. The issues for liquid-metal blankets are dominated by magnetohydrodynamic (MHD) effects on fluid flow and heat transfer. New design solutions have been proposed, new facilities have been constructed, and models are being developed to address MHD effects. The problems of solid breeder blankets are dominated by tritium release, containment, and inventory. There has been remarkable progress in understanding tritium transport in solid breeders because of successful irradiation experiments of solid breeders in fusion reactors. New models on tritium transport have provided key tools for the analysis and interpretation of the experimental results, A new issue related to thermal control in solid breeder is the subject of active experimental and mod... | 161,621 |
title: The International Pulsar Timing Array; abstract: The International Pulsar Timing Array (IPTA) is an organization whose raison d’etre is to facilitate collaboration between the three main existing PTAs (the EPTA in Europe, NANOGrav in North America and the PPTA in Australia) in order to realize the benefits of combined PTA data sets in reaching the goals of PTA projects. Currently, shared data sets for 50 pulsars are available for IPTA-based projects. Operation of the IPTA is administered by a Steering Committee consisting of six members, two from each PTA, plus the immediate past Chair in a non-voting capacity. A Constitution and several Agreements define the framework for the collaboration. Web pages provide information both to members of participating PTAs and to the general public. With support from an NSF PIRE grant, the IPTA facilitates the organization of annual Student Workshops and Science Meetings. These are very valuable both in training new students and in communicating current results from IPTA-based research. | 161,622 |
title: Fabrication and evaluation of a freestanding pyroelectric detector made from single-crystal LiNbO(3) film.; abstract: We have packaged a rectangular 3 mm×4 mm, 10‐µm-thick Z-cut lithium niobate LiNbO3 film produced by crystal ion slicing (CIS) and evaluated its performance as a pyroelectric optical detector. We justify the difficulty of preparing the film by showing that the freestanding detector has much greater sensitivity than the same detector bonded to a substrate. We compare the sensitivity of three CIS-film detectors with that of a detector based on a 230‐µm-thick LiNbO3 plate and describe the detectors’ spatial uniformity and noise-equivalent power. | 161,623 |
title: Multi-mode Control in a Two-stage Piezoelectric Transducer for an Application of Physical Therapy; abstract: A novel as well as unique piezoelectric-driven system constructed with two sets of ceramic actuators connected in a series is able to produce both mechanical vibration and electric power at the output end. With power input to the first ceramic actuator to oscillate, the connected second one makes use of the transmitted mechanical vibration energy to generate electricity via piezoelectric direct effect. An application example of physical therapy including ultrasonic diathermy and electrotherapy is selected for further investigation in this article. Different from the traditional ultrasonic diathermy and electrotherapy systems that are built with their own specific method and independent structure, the developed two-stage piezoelectric transducer can achieve the same application purpose alone. Multi-mode control scheme is proposed by using Frequency- Hopping method to oscillate the first ceramic actuator with different vibration amplitude at various resonance frequencies under schematic switching process. H... | 161,624 |
title: Cosmology based on f(R) gravity with (1) eV sterile neutrino; abstract: We address the cosmological role of an additional (1) eV sterile neutrino in modified gravity models. We confront the present cosmological data with predictions of the FLRW cosmological model based on a variant of f(R) modified gravity proposed by one of the authors previously. This viable cosmological model which deviation from general relativity with a cosmological constant Λ decreases as R−2n for large, but not too large values of the Ricci scalar R (while no Λ is introduced by hand at small R) provides an alternative explanation of present dark energy and the accelerated expansion of the Universe (the case n=2 is considered in the paper). Various up-to-date cosmological data sets exploited include measurements of the cosmic microwave background (CMB) anisotropy, the CMB lensing potential, the baryon acoustic oscillations (BAO), the cluster mass function and the Hubble constant. We find that the CMB+BAO constraints strongly restrict the sum of neutrino masses from above. This excludes values of the model parameter λ~ 1 for which distinctive cosmological features of the model are mostly pronounced as compared to the ΛCDM model, since then free streaming damping of perturbations due to neutrino rest masses is not sufficient to compensate their extra growth occurring in f(R) modified gravity. Thus, in the gravity sector we obtain λ\u003e8.2 (2σ) with the account of systematic uncertainties in galaxy cluster mass function measurements and λ\u003e9.4 (2σ) without them. At the same time in the latter case we find for the sterile neutrino mass 0.47 eV \u003c mν, sterile \u003c 1 eV (2σ) assuming that the sterile neutrinos are thermalized and the active neutrinos are massless, not significantly larger than in the standard ΛCDM with the same data set: 0.45 eV \u003c mν, sterile \u003c 0.92 eV (2σ). However, a possible discovery of a sterile neutrino with the mass mν, sterile ≈ 1.5 eV motivated by various anomalies in neutrino oscillation experiments would favor cosmology based on f(R) gravity rather than the ΛCDM model. | 161,625 |
title: Molecular Dynamics Studies of Properties of Supercritical Fluids; abstract: This work involves the determination of transport coefe cients and equation of state of supercritical e uids by equilibrium molecular dynamics (MD) simulations on parallel computers using the Green ‐Kubo formulas and the virial equation of state, respectively. The MD program uses the effective Lennard ‐ Jones potential, linked-cell lists for efe cient sorting of molecules, periodic boundary conditions, and a modie ed velocity Verlet algorithm for particle displacement. Simulations have been carried out on pure oxygen at various supercritical conditions, with shear viscosity and thermal conductivity coefe cients, and pressures computed for most of the conditions. Preliminary results compare well with experimental and the National Institute of Standards and Technology (experimental ) results. Results show that the number of molecules and the potential cutoff radius have no signie cant effect on the computed coefe cients, while long-time integrations are necessary for accurate determination of the coefe cients. Nomenclature A = equation constant a = acceleration vector ij da = desired separation distance between two atoms in a molecule i = unit tensor Jp = stress tensor Jq = heat tensor kB = Boltzmann constant m = molecular mass N = number of molecules in the system n = number of atoms per molecule P = pressure RC a = c.m. velocity of a given molecule Rab = c.m. position vector between two molecules r = position vector i ra = position vector of a given atom ij rab = position vector between two atoms i, j T = temperature t = time td = time delay t0 = time origin V = volume v = velocity vector i | 161,626 |
title: Disorder effects at low temperatures in La0.7−xYxCa0.3MnO3 manganites; abstract: Abstract With the aim of probing the effect of magnetic disorder in the low-temperature excitations of manganites, specific heat measurements were performed in zero field, and in magnetic fields up to 9 T in polycrystalline samples of La0.7−xYxCa0.3MnO3, with Y concentrations x=0, 0.10, and 0.15. Yttrium doping yielded the appearance of a cluster-glass state, giving rise to unusual low-temperature behavior of the specific heat. The main feature observed in the results is a strong enhancement of the specific heat linear term, which is interpreted as a direct consequence of magnetic disorder. The analysis was further corroborated by resistivity measurements in the same compounds. | 161,627 |
title: Synthesis and magnetic properties of nickel nanoparticles in magnesium fluoride matrix; abstract: A new composite material, comprising a diamagnetic matrix (magnesium fluoride) containing metal nanoparticles (nickel), has been synthesized in a high-vacuum laser-based universal cluster ablation system. The structure and magnetic properties of the composite were studied by transmission electron microscopy (TEM) and ferromagnetic resonance (FMR). According to TEM data, the nickel nanoparticles have a spherical shape and their dimensions are described by a narrow distribution function with an average value of 3.2 nm. An analysis of the FMR spectra reveals strong interaction between nickel nanoparticles in the composite, which accounts for an out-of-plane magnetic anisotropy and suggests the formation of granular magnetic films. | 161,628 |
title: THE LINEARITY OF THE COSMIC EXPANSION FIELD FROM 300 TO 30,000 km s–1 AND THE BULK MOTION OF THE LOCAL SUPERCLUSTER WITH RESPECT TO THE COSMIC MICROWAVE BACKGROUND; abstract: The meaning of \"linear expansion\" is explained. Particularly accurate relative distances are compiled and homogenized for (1) 246 Type Ia supernovae and 35 clusters with v 3500 km s–1—for a 495 km s–1 motion of the Local Supercluster toward the warm cosmic microwave background (CMB) pole at l = 275, b = 12; local peculiar motions are averaged out by large numbers. A test for linear expansion shows that the corrected velocities increase with distance as predicted by a standard model with q 0 = –0.55 (corresponding to (ΩM, ΩΛ) = (0.3, 0.7)), but the same holds—due to the distance limitation of the present sample—for a range of models with q 0 between ~0.00 and –1.00. For these models H 0 does not vary systematically by more than ±2.3% over the entire range. Local, distance-dependent variations are equally limited to 2.3% on average. In particular, the proposed Hubble Bubble of Zehavi et al. and Jha et al. is rejected at the 4σ level. Velocity residuals in function of the angle from the CMB pole yield a satisfactory apex velocity of 448 ± 73 km s–1 and a coherence radius of the Local Supercluster of ~3500 km s–1 (~56 Mpc), beyond which galaxies are seen on average at rest in comoving coordinates with respect to the CMB. Since no obvious single accelerator of the Local Supercluster exists in the direction of the CMB dipole, its motion must be due to the integral gravitational force of all surrounding structures. Most of the gravitational dipole probably come from within 5000 km s–1. | 161,629 |
title: Substrate-dependent thermal conductivity of aluminum nitride thin-films processed at low temperature; abstract: In this paper, we report on investigation concerning the substrate-dependent thermal conductivity (k) of Aluminum Nitride (AlN) thin-films processed at low temperature by reactive magnetron sputtering. The thermal conductivity of AlN films grown at low temperature (\u003c200 °C) on single-crystal silicon (Si) and amorphous silicon nitride (SiN) with thicknesses ranging from 100 nm to 4000 nm was measured with the transient hot-strip technique. The k values for AlN films on SiN were found significantly lower than those on Silicon consistently with their microstructures revealed by X-ray diffraction, high resolution scanning electron microscopy, and transmission electron microscopy. The change in k was due to the thermal boundary resistance found to be equal to 10 × 10−9 Km2W−1 on SiN against 3.5 × 10−9 Km2W−1 on Si. However, the intrinsic thermal conductivity was determined with a value as high as 200 Wm−1K−1 whatever the substrate. | 161,630 |
title: Collisionally induced alignment produced by electron and light-ion impact: Auger electron emission following 2p ionisation and excitation; abstract: A detailed study of the collisionally induced alignment of the 2p electron is presented. The collision systems investigated are e-, H+, He and Li+ with Mg for emission following 2p ionisation and e- and H+ with Na and Mg+ with He for emission following 2 p excitation. Impact velocities, scaled with respect to the threshold velocity of the process being studied, ranged from approximately electron threshold ( nu rel=1) to nu rel=7 for electron impact and nu rel=0.1-5 for the combined ion impact data. A comparison of the measured alignments for the various projectiles with each other and with theory is made for the two cases. Specific comparisons demonstrate how kinematics effect at lower velocities. In addition, pronounced maxima-minima structures resulting from nodes in the target wavefunctions are observed. Finally, the fires measurements of alignment in the region of electron threshold are presented and a prediction of the threshold alignment value is made in the case of 2p ionisation by electron impact. | 161,631 |
title: Thermal coefficients of the electrical resistivity of Ge nanocrystals on Si for infrared detectors; abstract: Abstract The resistivity and capacitance of Ge nanocrystal thin films are measured as a function of temperature. The films are produced by pulsed excimer laser deposition (KrF, λ =248 nm). The morphology of the nanocrystalline Ge film is confirmed by atomic force microscopy (AFM). The absolute value of temperature coefficients of the resistance (TCR) exceeds 4% kΩ/K determined by I – V , and temperature coefficients of capacitance (TCC) is up to 4% pF/K by C – V measurements in the temperature range of 220–270 K, respectively. For Ge nanocrystals smaller than 100 nm, the coefficients increase sharply with the decreasing size. This is attributed to quantum confinement. | 161,632 |
title: The effect of a meridional flow on Parker's interface dynamo; abstract: Parker\u0027s interface dynamo is generalized to the case when a homogeneous flow is present in the high-diffusivity (upper) layer in the lateral direction (i.e. perpendicular to the shear flow in the lower layer). This is probably a realistic first representation of the situation near the bottom of the solar convective zone, as the strongly subadiabatic stratification of the tachocline (lower layer in the interface dynamo) imposes a strong upper limit on the speed of any meridional flow there.\r\n\r\n\r\n\r\nAnalytic solutions to the eigenvalue problem are presented for the cases of vanishing diffusivity contrast and infinite diffusivity contrast. Unlike the trivial case of a homogeneous system, the ability of the meridional flow to reverse the propagation of the dynamo wave is strongly reduced in the interface dynamo. In particular, in the limit of high diffusivity contrast relevant to the solar case it is found that a meridional flow of realistic amplitude cannot reverse the direction of propagation of the dynamo wave. The implications of this result for the solar dynamo problem are discussed. | 161,633 |
title: Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS II. The complete high resolution extinction map and implications for Galactic bulge studies; abstract: Context. The Milky Way bulge is the nearest galactic bulge and the most readily accessible laboratory for studies of stellar populations in spheroids based on individual stellar abundances and kinematics. These studies are challenged by the strongly variable and often large extinction on a small spatial scale. Aims. We use the Vista Variables in the Via Lactea (VVV) ESO public survey data to measure extinction values in the complete area of the Galactic bulge covered by the survey at high resolution. Methods. We derive reddening values using the method described in Paper I. This is based on measuring the mean (J − Ks) color of red clump giants in small subfields of 2 � × 2 � to 6 � × 6 � in the following bulge area: −10.3 ◦ ≤ b ≤ +5.1 ◦ and −10.0 ◦ ≤ l ≤ +10.4 ◦ . To determine the reddening values E(J − Ks) for each region, we measure the RC color and compare it to the (J − Ks) color of RC stars measured in Baade’s Window, for which we adopt E(B − V) = 0.55. This allows us to construct a reddening map sensitive to small-scale variations minimizing the problems arising from differential extinction. Results. The significant reddening variations are clearly observed on spatial scales as small as 2 � . We find good agreement between our extinction measurements and Schlegel maps in the outer bulge, but, as already stated in the literature the Schlegel maps are unreliable for regions within |b| \u003c 6 ◦ . In the inner regions, we compare our results with maps derived from DENIS and Spitzer surveys. While we find good agreement with other studies in the corresponding overlapping regions, our extinction map is of higher quality owing to both its higher resolution and a more complete spatial coverage of the bulge. We investigate the importance of differential reddening and demonstrate the need for high spatial resolution extinction maps for detailed studies of bulge stellar populations and structure. Conclusions. We present the first extinction map covering uniformly ∼315 sq. deg. of the Milky Way bulge at high spatial resolution. We consider a 30 arcmin window at a latitude of b = −4 ◦ , which corresponds to a frequently studied low extinction window, the so-called Baade’s Window, and find that its AKs values can vary by up to 0.1 mag. Larger extinction variations are observed at lower Galactic latitudes. The extinction variations on scales of up to 2 � −6 � must be taken into account when analyzing the stellar populations of the Galactic bulge. | 161,634 |
title: Adding helicity to inflationary magnetogenesis; abstract: The most studied mechanism of inflationary magnetogenesis relies on the time-dependence of the coefficient of the gauge kinetic term $F_{\\mu\\nu}\\,{F}^{\\mu\\nu}$. Unfortunately, only extremely finely tuned versions of the model can consistently generate the cosmological magnetic fields required by observations. We propose a generalization of this model, where also the pseudoscalar invariant $F_{\\mu\\nu}\\,\\tilde{F}^{\\mu\\nu}$ is multiplied by a time dependent function. The new parity violating term allows more freedom in tuning the amplitude of the field at the end of inflation. Moreover, it leads to a helical magnetic field that is amplified at large scales by magnetohydrodynamical processes during the radiation dominated epoch. As a consequence, our model can satisfy the observational lower bounds on fields in the intergalactic medium, while providing a seed for the galactic dynamo, if inflation occurs at an energy scale ranging from $10^5$ to $10^{10}$ GeV. Such energy scale is well below that suggested by the recent BICEP2 result, if the latter is due to primordial tensor modes. However, the gauge field is a source of tensors during inflation and generates a spectrum of gravitational waves that can give a sizable tensor to scalar ratio $r={\\cal O}(0.2)$ even if inflation occurs at low energies. This system therefore evades the Lyth bound. For smaller values of $r$, lower values of the inflationary energy scale are required. The model predicts fully helical cosmological magnetic fields and a chiral spectrum of primordial gravitational waves. | 161,635 |
title: Theoretical analysis of ESR measurements in (GdxY1−xCu; abstract: Abstract A theoretical analysis of ESR measurements in (Gd x Y 1−x Cu [ x ⊂ (0, 1)] which explains consistently the observed positive g shifts in unbottlenecked region and negative g shifts in bottlenecked region is performed. The concentration dependent density of states and the coherent scattering of the electrons by the impurities are taken into account. The theoretical calculations are in good agreement with experimental data. | 161,636 |
title: Short-Duration Gamma-Ray Bursts; abstract: Gamma-ray bursts (GRBs) display a bimodal duration distribution with a separation between the short- and long-duration bursts at about 2 s. The progenitors of long GRBs have been identified as massive stars based on their association with Type Ic core-collapse supernovae (SNe), their exclusive location in star-forming galaxies, and their strong correlation with bright UV regions within their host galaxies. Short GRBs have long been suspected on theoretical grounds to arise from compact object binary mergers (neutron star–neutron star or neutron star–black hole). The discovery of short GRB afterglows in 2005 provided the first insight into their energy scale and environments, as well as established a cosmological origin, a mix of host-galaxy types, and an absence of associated SNe. In this review, I summarize nearly a decade of short GRB afterglow and host-galaxy observations and use this information to shed light on the nature and properties of their progenitors, the energy scale and collimation of the re... | 161,637 |
title: Charge-carrier transport in smectic mesophases of biphenyls; abstract: The charge-transport properties of ω,ω′-alkylalkoxylbiphenyls, one of the simplest calamitic (rodlike) liquid crystals exhibiting smectic mesophases, were investigated using the time-of-flight experiments. A mobility of ∼10−3 cm2∕V s was determined for holes in both smectic B (SmB) and smectic E (SmE) phases. This high electronic mobility, comparable to the highest mobilities in amorphous organic semiconductors, indicates that the self-organization of such simple molecules including small aromatic compounds is quite effective in enhancing the charge transport in organic materials. The mobilities of both smectic mesophases, however, depend on temperatures, which is not the case for other typical smectic liquid crystals reported previously. Interestingly, the mobility in the SmE phase exhibits a Poole–Frenkel type of field dependence. Detailed experimental studies have shown that this field dependence is not due to the trapping effect of carriers caused by chemical contaminants or structural defects such as... | 161,638 |
title: Self-interaction spin effects in inspiralling compact binaries; abstract: Gravitational radiation drives compact binaries through an inspiral phase towards a final coalescence. For binaries with spin, mass quadrupole, and magnetic dipole moments, various contributions add to this process, which is characterized by the rate of increase $df/dt$ of the gravitational wave frequency and the accumulated number $\\mathcal{N}$ of gravitational wave cycles. We present here all contributions to $df/dt$ and $\\mathcal{N}$ up to the second post-Newtonian order. Among them we give for the first time the contributions due to the self-interaction of individual spins. These are shown to be commensurable with the proper spin-spin contributions for the recently discovered J0737-3039 double pulsar and argued to represent the first corrections to the radiation reaction in the Lense-Thirring approach. | 161,639 |
title: Scattering of high energy electrons and nucleons from 4He and nucleon - nucleon correlations; abstract: Abstract An attempt is made to give a coherent explanation of the recent experiments on the elastic electron and nucleon scattering from 4He. | 161,640 |
title: Quantum-mechanical theory of atom-molecule and molecular collisions in a magnetic field: Spin depolarization; abstract: A theory for quantum-mechanical calculations of cross sections for atom-molecule and molecular collisions in a magnetic field is presented. The formalism is based on the representation of the wave function as an expansion in a fully uncoupled space-fixed basis. The systems considered include 1S-atom–2Σ-molecule, 1S-atom–3Σ-molecule, 2Σ-molecule–2Σ-molecule, and 3Σ-molecule–3Σ-molecule. The theory is used to elucidate the mechanisms for collisionally induced spin depolarization. | 161,641 |
title: Binding energy effects in the decay properties of charmonia; abstract: The di-gamma and di-gluon decay widths of P-wave c mesons are computed in nonrelativistic phenomenological quark-antiquark potential of the type with different choices of ? using spectroscopic parameters. The numerically obtained radial solutions are employed to obtain the di-gamma and di-gluon decay widths. The computed decay widths are consistent with other model predictions as well as with the known experimental values in the range of potential index 0.7 ? ? ? 1.1. | 161,642 |
title: Fabrication of 100-Oriented (Na0.5K0.5)NbO3–BaZrO3–(Bi0.5Li0.5)TiO3Films on Si Substrate Using LaNiO3Layer; abstract: 0.92(Na0.5K0.5)NbO3–0.06BaZrO3–0.02(Bi0.5Li0.5)TiO3 (NKN–BZ–BLT) thin films were fabricated by pulsed laser deposition (PLD) on a (100)Si substrate on which a 100-oriented LaNiO3 (LNO) bottom layer was fabricated by the chemical solution deposition method. The NKN–BZ–BLT films were characterized by X-ray diffraction (XRD) analysis, θ/2θ scan and ψ–2θ/ω scan, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The properties were compared with those of the NKN–BZ–BLT film deposited on the (111)Pt/Ti/SiO2/(100)Si substrate. We demonstrated that the LNO layer plays an important role in obtaining 100-oriented NKN–BZ–BLT films on the Si substrate. SEM surface and cross-sectional images showed that the NKN–BZ–BLT films fabricated at a substrate temperature of 800 °C had a high density and a relatively smooth surface. From the TEM image, this NKN–BZ–BLT film fabricated at 800 °C was composed of the columnar grains and some vertical-long pores could be observed. The energy dispersive X-ray (EDX) analysis showed that the LNO layer is decomposed to La2NiO4 by its reaction with Nb. The dielectric properties showed that the NKN–BZ–BLT film on the LNO electrode had a small dielectric constant of 82, compared with the NKN–BZ–BLT film (er = 3127) on the (111)Pt/Ti/SiO2/(100)Si substrate. This difference is due to the polarization direction of the film and the polarization axis of the NKN–BZ–BLT film on the LNO electrode exists in a direction perpendicular to the surface of the substrate. However, the NKN–BZ–BLT film on LNO showed a small Pr value. This is due to the dispersion of Ni from the LNO layer. | 161,643 |
title: Quantum Instability of Magnetized Stellar Objects; abstract: The equations of state for degenerate electron and neutron gases are studied in the presence of magnetic fields. After including quantum effects in the investigation of the structural properties of these systems, it is found that some hypermagnetized stars can be unstable according to the criterion of stability of pressures. Highly magnetized white dwarfs should collapse producing a supernova type Ia, while superstrong magnetized neutron stars cannot stand their own magnetic field and must implode, too. A comparison of our results with a set of the available observational data of some compact stars is also presented, and the agreement between this theory and observations is verified. | 161,644 |
title: Gravity turbulence connected with interfaces; abstract: The spectral distributions of turbulence, as generated by the gravity waves on the interface between two fluids, are investigated. Both stable and unstable surfaces are considered. An unstable surface refers to the early development of turbulence from the Taylor instability. A stable surface may refer to the sea-surface. A repeated-cascade method is used to close the hierarchy of correlations at their fourth order, and to determine the eddy transport property through a memory chain of eddy relaxations. The production, inertia and dissipation subranges of spectral distributions on an unstable surface with friction are found to follow the laws k ?2 , k ?3 , and k ?3 for the kinetic energy, and k ?3.5 , k ?1 , and k ?5 for the surface elevation. The inertia, eddy dissipation by gravity, and molecular dissipation subranges on a stable surface with friction are found to follow the law k ?3 for the kinetic energy, and the laws k ?1 , k ?5 and k ?5 for the surface elevation, respectively. The effects of surface tension are also investigated. DOI: 10.1111/j.2153-3490.1974.tb01634.x | 161,645 |
title: A MEMS-based piezoelectric cantilever patterned with PZT thin film array for harvesting energy from low frequency vibrations; abstract: Abstract A piezoelectric energy harvesting cantilever integrated with Si proof mass has been presented to realize a low resonant frequency of 35.8 Hz. This paper describes the design, microfabrication and measurement of such device for harvesting energy from low frequency environmental vibrations. Instead of deposition of PZT bulk film, ten PZT thin film patterns (PZT patterns) are parallel arrayed and electrically isolated on the supporting beam of the cantilever. The performance of output voltage and power of PZT patterns in series and in parallel connections are studied based on the experimental and simulation results. It is shown that PZT patterns in series and in parallel connections produce the same level of power in the corresponding matched load resistance, but PZT patterns in parallel connection is preferred because of lower matched load resistance required. | 161,646 |
title: Investigation of the 16O(γ, n)15O and 12C(γ, n)11C reaction at photon energies between 150 MeV and 63 MeV; abstract: Abstract Measurements of the energy distribution of high energy neutrons emitted in the photo-disintegration of 16 O and 12 C have been performed with a time of flight method for four angles (40.2°, 90°, 113.5°, 142.2°) using the electron beam (60 MeV ≦ E ≦ 150 MeV) of the Mainz University Electron Linac. Neutron spectra for “monochromatic” photons were obtained by a difference method. The cross sections extracted from these spectra show a pronounced forward asymmetry and decrease rapidly with increasing photon energy. The data can be described by a phenomenological quasi-deuteron model. | 161,647 |
title: Paving the way to simultaneous multi-wavelength astronomy; abstract: Whilst astronomy as a science is historically founded on observations at optical wavelengths, studying the Universe in other bands has yielded remarkable discoveries, from pulsars in the radio, signatures of the Big Bang at submm wavelengths, through to high energy emission from accreting, gravitationally-compact objects and the discovery of gamma-ray bursts. Unsurprisingly, the result of combining multiple wavebands leads to an enormous increase in diagnostic power, but powerful insights can be lost when the sources studied vary on timescales shorter than the temporal separation between observations in different bands. In July 2015, the workshop \"Paving the way to simultaneous multi-wavelength astronomy\" was held as a concerted effort to address this at the Lorentz Center, Leiden. It was attended by 50 astronomers from diverse fields as well as the directors and staff of observatories and spaced-based missions. This community white paper has been written with the goal of disseminating the findings of that workshop by providing a concise review of the field of multi-wavelength astronomy covering a wide range of important source classes, the problems associated with their study and the solutions we believe need to be implemented for the future of observational astronomy. We hope that this paper will both stimulate further discussion and raise overall awareness within the community of the issues faced in a developing, important field. | 161,648 |
title: Self-Calibrating Vector Atomic Magnetometry through Microwave Polarization Reconstruction.; abstract: Atomic magnetometry is one of the most sensitive ways to measure magnetic fields. We present a method for converting a naturally scalar atomic magnetometer into a vector magnetometer by exploiting the polarization dependence of hyperfine transitions in rubidium atoms. First, we fully determine the polarization ellipse of an applied microwave field using a self-calibrating method, i.e., a method in which the light-atom interaction provides everything required to know the field in an orthogonal laboratory frame. We then measure the direction of an applied static field using the polarization ellipse as a three-dimensional reference defined by Maxwell\u0027s equations. Although demonstrated with trapped atoms, this technique could be applied to atomic vapors, or a variety of atomlike systems. | 161,649 |
title: Electronic transport within a quasi-two-dimensional model for rubrene single-crystal field effect transistors; abstract: Spectral and transport properties of the quasi-two-dimensional adiabatic Su-Schrieffer-Heeger model are studied, adjusting the parameters in order to model rubrene single-crystal field effect transistors with small but finite density of injected charge carriers. We show that, with increasing temperature $T$, the chemical potential moves into the tail of the density of states corresponding to localized states, but this is not enough to drive the system into an insulating state. The mobility along different crystallographic directions is calculated, including vertex corrections that give rise to a transport lifetime one order of magnitude smaller than the spectral lifetime of the states involved in the transport mechanism. With increasing temperature, the transport properties reach the Ioffe-Regel limit, which is ascribed to less and less appreciable contribution of itinerant states to the conduction process. The model provides features of the mobility in close agreement with experiments: right order of magnitude, scaling as a power law ${T}^{\\ensuremath{-}\\ensuremath{\\gamma}}$ (with $\\ensuremath{\\gamma}$ close or larger than two), and correct anisotropy ratio between different in-plane directions. Due to a realistic high-dimensional model, the results are not biased by uncontrolled approximations. | 161,650 |
title: From first-order magneto-elastic to magneto-structural transition in (Mn,Fe)1.95P0.50Si0.50 compounds; abstract: We report on structural, magnetic and magnetocaloric properties of MnxFe1.95-xP0.50Si0.50 (x \u003e 1.10) compounds. With increasing the Mn:Fe ratio, a first-order magneto-elastic transition gradually changes into a first-order magneto-structural transition via a second-order magnetic transition. The study also shows that thermal hysteresis can be tuned by varying the Mn:Fe ratio. Small thermal hysteresis (less than 1 K) can be obtained while maintaining a giant magnetocaloric effect. This achievement paves the way for real refrigeration applications using magnetic refrigerants. | 161,651 |
title: Gravitoastronomy with neutron stars; abstract: Recent advances in gravitational wave detectors mean that we can start to make astrophysically important statements about the physics of neutron stars based on observed upper limits to their gravitational luminosity. Here we consider statements we can already make about a selection of known radio pulsars, based on data from the LIGO and GEO600 detectors, and look forward to what could be learned from the first detections. | 161,652 |
title: Photometric calibration of the first three spectroscopic orders of an extreme-ultraviolet spectrometer by use of synchrotron radiation.; abstract: We report here a technique for determining the quantum throughput of a high-resolution, extreme-UV spectrometer by use of the National Institute of Standards and Technology’s Synchroton Ultraviolet Radiation Facility at Gaithersburg, Md. (SURF-II). Observations were obtained at three different synchrotron operating energies with and without a magnesium fluoride filter and a tin–germanium filter. This calibration permits us to extract system efficiencies for three overlapping spectroscopic orders with uncertainties of 10–30%. The uncertainties quoted in this preliminary experiment were limited by the available time, and we propose that with minor refinements a significant improvement could be realized. | 161,653 |
title: The physics of core-collapse supernovae; abstract: Supernovae are nature’s grandest explosions and an astrophysical laboratory in which unique conditions exist that are not achievable on Earth. They are also the furnaces in which most of the elements heavier than carbon have been forged. Scientists have argued for decades about the physical mechanism responsible for these explosions. It is clear that the ultimate energy source is gravity, but the relative roles of neutrinos, fluid instabilities, rotation and magnetic fields continue to be debated. | 161,654 |
title: Secular perihelion advances of the inner planets and asteroid Icarus; abstract: Abstract A small effect expected from a recently proposed gravitational impact model (Wilhelm et al., 2013) is used to explain the remaining secular perihelion advance rates of the planets Mercury, Venus, Earth, Mars, and the asteroid (1566) Icarus—after taking into account the disturbances related to Newton’s Theory of Gravity. Such a rate was discovered by Le Verrier (1859) for Mercury and calculated by Einstein (1915, 1916) in the framework of his General Theory of Relativity (GTR). Accurate observations are now available for the inner Solar System objects with different orbital parameters. This is important, because it allowed us to demonstrate that the quantitative amount of the deviation from an 1/r potential is—under certain conditions—only dependent on the specific mass distribution of the Sun and not on the characteristics of the orbiting objects and their orbits. A displacement of the effective gravitational from the geometric centre of the Sun by about 4400 m towards each object is consistent with the observations and explains the secular perihelion advance rates. | 161,655 |
title: The Monte Carlo method; abstract: We give here a detailed technical description of a Monte Carlo scheme for the dynamical evolution of spherical stellar systems. The philosophy of the method, as well as a few illustrative results, are given elsewhere (Henon, 1971, hereafter called I). | 161,656 |
title: Enhancement of the Higgs pair production at the CERN LHC: The minimal supersymmetric standard model and extra dimension effects; abstract: Neutral Higgs pair production at the CERN LHC is studied in the MSSM, the large extra dimensional (ADD) model and the Randall-Sundrum (RS) model, where the total cross section can be significantly enhanced compared to that in the SM. The p{sub T}, invariant mass and rapidity distributions of each model have been shown to be distinctive: The ADD model raises the p{sub T} and invariant mass distributions at high scales of p{sub T} and invariant mass; in the RS model, resonant peaks appear after the SM contribution dies away; the SM and the MSSM distributions drop rapidly at those high scales; in the ADD and the RS models, the rapidity distributions concentrate more around the center. We conclude that various distributions of Higgs pair production at the LHC with restrictive kinematic cuts would provide one of the most robust signals for the extra dimensional effects. | 161,657 |
title: Comparison of the Z/gamma* + jets to gamma + jets cross sections in pp collisions at sqrt(s) = 8 TeV; abstract: A comparison of the differential cross sections for the processes Z/gamma* + jets and photon (gamma) + jets is presented. The measurements are based on data collected with the CMS detector at sqrt(s) = 8 TeV corresponding to an integrated luminosity of 19.7 inverse femtobarns. The differential cross sections and their ratios are presented as functions of pt. The measurements are also shown as functions of the jet multiplicity. Differential cross sections are obtained as functions of the ratio of the Z/gamma* pt to the sum of all jet transverse momenta and of the ratio of the Z/gamma* pt to the leading jet transverse momentum. The data are corrected for detector effects and are compared to simulations based on several QCD calculations. | 161,658 |
title: The annular gap model for γ-ray emission from young and millisecond pulsars; abstract: Pulsed high-energy radiation from pulsars is not yet completely understood. In this paper, we use the 3D self-consistent annular gap model to study light curves for both young and millisecond pulsars (MSPs) observed by the Fermi Gamma-ray Space Telescope. The annular gap can generate high-energy emission for short-period pulsars. The annular gap regions are so large that they have enough electric potential drop to accelerate charged particles to produce γ-ray photons. For young pulsars, the emission region is from the neutron star surface to about half of the light cylinder radius, and the peak emissivity is in the vicinity of the null charge surface. The emission region for the millisecond pulsars is located much lower than that of the young pulsars. The higher energy γ-ray emission comes from higher altitudes in the magnetosphere. We present the simulated light curves for three young pulsars (the Crab, the Vela and the Geminga) and three millisecond pulsars (PSR J0030+0451, PSR J0218+4232 and PSR J0437-3715) using the annular gap model. Our simulations can reproduce the main properties of the observed light curves. | 161,659 |
title: Coordinate detectors based on thin-wall drift tubes; abstract: Design features and basic parameters of the detectors based on straw trackers are reviewed using the example of the studies and development of trackers in a number of operating and proposed accelerator experimental facilities. The results of methodological studies aimed at qualitatively improving the spatial/time resolution and high rate capability of the detector and enhancing the performance capabilities of such detectors used for particle detection in a high multiplicity environment (and in high-luminosity experiments) are presented. | 161,660 |
title: Influence of chemical prehistory on the colossal magnetoresistance of La0.7Ca0.3MnO3 ceramics; abstract: Abstract Evolution of magnetoresistance at H =1.5 T during sintering of ceramics is studied for La 0.7 Ca 0.3 MnO 3 samples obtained using solid state (SS) synthesis and freeze-drying (FD) methods. Significant enhancement of magnetoresistance peak values and lowering of peak temperature for dense SS samples can be related to larger oxygen non-stoichiometry due to complicated oxygen diffusion or influence of La-doped MnO x inclusions, generating new pinning centers. | 161,661 |
title: Slip-flow and heat transfer in rectangular microchannels with constant wall temperature; abstract: Abstract Rarefied gas flow and heat transfer in the entrance region of rectangular microchannels are investigated numerically in the slip-flow regime. A control-volume based numerical method is used to solve the Navier–Stokes and energy equations with velocity-slip and temperature-jump conditions at the walls. The effects of Reynolds number ( 0.1 ⩽ Re ⩽ 10 ), channel aspect ratio ( 0 ⩽ α ∗ ⩽ 1 ), and Knudsen number ( Kn ⩽ 0.1 ) on the simultaneously developing velocity and temperature fields, and on the key flow parameters like the entrance length, the friction coefficient, and Nusselt number are examined in detail. In the entrance region, very large reductions are observed in the friction factor and Nusselt number due to rarefaction effects, which also extend to the fully developed region (though at much lower levels). Current results show that the friction and heat transfer coefficients are less sensitive to rarefaction effects in corner-dominated flows as in square channels when compared to flows between parallel plates. Practical engineering correlations are proposed for the friction and heat transfer coefficients in rectangular and trapezoidal channels. | 161,662 |
title: Interaction of Rayleigh-Taylor Fingers and Circumstellar Clodlets in Young Supernova Remnants; abstract: We discover a new dynamical mechanism that significantly enhances the growth of Rayleigh-Taylor fingers developed near the contact interface between the supernova ejecta and swept-up ambient gas in young supernova remnants if the supernova remnant expands into a clumpy (cloudy) circumstellar medium. Our numerical simulation demonstrates that large Rayleigh-Taylor fingers can obtain a sufficient terminal velocity to protrude through the forward shock front by taking extra kinetic energy from vorticies generated by shock-cloud interactions. We suggest this mechanism as a means to generate the aspherical expansion of the supernova ejecta. Ambient magnetic fields are stretched and amplified as the Rayleigh-Taylor fingers protrude, possibly leading to strongly enhanced radio emission. The material in the protrusions originates from the ejected stellar material with greatly enhanced heavy elements. Therefore, it can be a strong X-ray emitter. The timescale for the Rayleigh-Taylor fingers to reach the forward shock depends on the size, mass density and distribution of clouds being engulfed by the supernova shock, although the details will require further numerical investigation. | 161,663 |
title: Multiferroic BiFeO3 thin films processed via chemical solution deposition: Structural and electrical characterization; abstract: Polycrystalline BiFeO3 thin films were fabricated on (111)Pt∕Ti∕SiO2∕Si substrates via Bi-acetate- and Fe-acetylacetonate-based chemical solution deposition and spin-coating techniques. The processing parameters were optimized in order to obtain films with high resistivity. The optical properties (refractive indices and extinction coefficients) were measured by means of ellipsometry (HeNe laser, λ=632.8A). Microstructure characterization was made by means of atomic force microscopy, grazing incidence x-ray diffractometry (XRD), and texture analysis. Additionally, powders prepared from a stoichiometric precursor were investigated by means of thermogravimetric and differential thermal analyses and XRD. It is demonstrated that the formation of perovskite-type BiFeO3 is accompanied by the appearance of bismuth oxide at low temperatures which then transforms into Bi36Fe2O57. For the films it was found that annealing in oxygen leads to higher indices of refraction, lower roughness, and smaller grain size. Compl... | 161,664 |
title: Spectral characteristics of polymer micro-fiber MZI near 1550 nm; abstract: Abstract The authors have produced the polymer micro-fiber with a highly optical conductive efficiency of 83% and 89% for the pump light of 532 nm and 1550 nm, respectively. The authors constructed a Mach–Zehnder Interferometer (MZI) by a micro-manipulation method and measured the different interference spectra by micro-adjusting the path difference of the dual interference arms of MZI under a microscope. Due to the path difference, the coherent length of the corresponding spectrum continuously and slightly decreases from 20 μm, 13.5 μm, 10.6 μm to 8 μm. The relationships between this particular MZI structure and the surrounding temperature, as well as the refractive index changes can be determined via the evanescent field and the thermally induced expansion or contraction effect, which will be reflected in the interference spectrum. | 161,665 |
title: High-fidelity simulations of moving and flexible airfoils at low Reynolds numbers; abstract: The present paper highlights results derived from the application of a high-fidelity simulation technique to the analysis of low-Reynolds-number transitional flows over moving and flexible canonical configurations motivated by small natural and man-made flyers. This effort addresses three separate fluid dynamic phenomena relevant to small fliers, including: laminar separation and transition over a stationary airfoil, transition effects on the dynamic stall vortex generated by a plunging airfoil, and the effect of flexibility on the flow structure above a membrane airfoil. The specific cases were also selected to permit comparison with available experimental measurements. First, the process of transition on a stationary SD7003 airfoil section over a range of Reynolds numbers and angles of attack is considered. Prior to stall, the flow exhibits a separated shear layer which rolls up into spanwise vortices. These vortices subsequently undergo spanwise instabilities, and ultimately breakdown into fine-scale turbulent structures as the boundary layer reattaches to the airfoil surface. In a timeaveraged sense, the flow displays a closed laminar separation bubble which moves upstream and contracts in size with increasing angle of attack for a fixed Reynolds number. For a fixed angle of attack, as the Reynolds number decreases, the laminar separation bubble grows in vertical extent producing a significant increase in drag. For the lowest Reynolds number considered \\((Re_c = 10^4)\\), transition does not occur over the airfoil at moderate angles of attack prior to stall. Next, the impact of a prescribed high-frequency small-amplitude plunging motion on the transitional flow over the SD7003 airfoil is investigated. The motioninduced high angle of attack results in unsteady separation in the leading edge and in the formation of dynamic-stalllike vortices which convect downstream close to the airfoil. At the lowest value of Reynolds number \\((Re_c = 10^4)\\), transition effects are observed to be minor and the dynamic stall vortex system remains fairly coherent. For \\(Re_c = 4 \\times 10^4\\), the dynamic-stall vortex system is laminar at is inception, however shortly afterwards, it experiences an abrupt breakdown associated with the onset of spanwise instability effects. The computed phased-averaged structures for both values of Reynolds number are found to be in good agreement with the experimental data. Finally, the effect of structural compliance on the unsteady flow past a membrane airfoil is investigated. The membrane deformation results in mean camber and large fluctuations which improve aerodynamic performance. Larger values of lift and a delay in stall are achieved relative to a rigid airfoil configuration. For \\(Re_c = 4.85 \\times 10^4\\), it is shown that correct prediction of the transitional process is critical to capturing the proper membrane structural response. | 161,666 |
title: Theoretical uncertainties for measurements of αs from electroweak observables; abstract: One of the most precise measurements of the strong coupling constant αs(MZ) is obtained in the context of global analyses of precision electroweak data. This article reviews the sensitivity of different electroweak observables to αs and describes the perturbative uncertainties related to missing higher orders. The complete renormalisation scale dependence for the relevant observables is calculated at next-to-next-to-leading order and a new method is presented to determine the corresponding perturbative uncertainty for measurements of αs based on these observables. | 161,667 |
title: Mode coupling of phonons in a dense one- dimensional microfluidic crystal; abstract: Long-living coupled transverse and longitudinal phonon modes are explored in dense, regular arrangements of flattened microfluidic droplets. The collective oscillations are driven by hydrodynamic interactions between the confined droplets and can be excited in a controlled way. Experimental results are quantitatively compared to simulation results obtained by multi-particle collision dynamics. The observed transverse modes are acoustic phonons and obey the predictions of a linearized far-field theory. The longitudinal modes arise from a nonlinear mode coupling due to the lateral variation of the confined flow field. The proposed mechanism for the nonlinear excitation is expected to be relevant for hydrodynamic motion in other crowded non-equilibrium systems under confinement. | 161,668 |
title: Analog black holes and energy extraction by super-radiance from Bose Einstein condensates (BEC) with constant density.; abstract: Abstract This paper investigates the acoustic superradiance of the density and phase fluctuations from the single vortex state of a Bose-Einstein condensate, by employing full time-domain and asymptotic frequency domain numerical calculations. The draining bathtub model of an incompressible barotropic fluid is adopted to describe the vortex. The propagation of the axisymmetric density and phase fluctuations in the condensate are governed by the massless scalar Klein-Gordon wave equation, which establishes the rotating black-hole analogy. Hence, the amplified scattering of these fluctuations from the vortex comprise the superradiance effect. A particular coordinate transformation is applied to reveal the event horizon and the ergosphere termwise in the metric and the respective asymptotic spectral solutions. A comparative analysis of the time domain and asymptotic frequency domain results are given for a range of rotational speed of the vortex and the frequency of the impinging fluctuations. The agreement at low rotational speeds of the vortex is shown to be very good, which starts to deteriorate at higher rotational speeds due to increasing constraint violations of the time-domain calculations. We further demonstrate an asymptotic upper bound for the superradiance as a function of vortex rotational speed, provided that the vortex remains stable. | 161,669 |
title: Numerical investigations on convective heat transfer enhancement in jet impingement due to the presence of porous media using Cascaded Lattice Boltzmann method; abstract: Abstract The present numerical study using the Lattice Boltzmann method investigates the convective heat transfer characteristics in impinging jets due to the inclusion of porous media. A cascaded collision model is employed in the present study, and the comparison with BGK collision model shows that the cascaded collision model is more stable and computationally efficient. The local thermal non equilibrium model (LTNE) or the two energy equation model is used in the present study to account for the local thermal non-equilibrium arising between the fluid and solid phase temperatures due to the high solid to fluid thermal conductivity ratios associated with metallic porous foams saturated with air. Two jet impingement configurations with porous media are modeled: jet impingement over a porous heat sink and jet impingement through a porous passage. Jet impingement over a porous heat sink is observed to be deteriorating the convective heat transfer whereas jet impingement through a porous passage showed enhancement. A parametric study is carried out for the porous passage configuration by varying the porous passage width from twice the jet width (2W) to once the jet width (W) and varying the Darcy number from 2.75e-2 to 2.75e-4. Jet impingement through a porous passage of width equal to the slot jet width is found to enhance the stagnation Nusselt number by 60.7% and the average Nusselt number by 53.7% compared to the jet impingement configuration in the absence of porous media. Similarly, lowering the Darcy number helps in augmenting the stagnation Nusselt number, however, it did not show any influence on the Nusselt number in the wall jet region. | 161,670 |
title: Short-Distance Structure of Nuclei; abstract: One of Jefferson Lab\u0027s original missions was to further our understanding of the short-distance structure of nuclei, in particular, to understand what happens when two or more nucleons within a nucleus have strongly overlapping wave-functions – a phenomena commonly referred to as short-range correlations. Herein, we review the results of the (e, e\u0027), (e, e\u0027p) and (e, e\u0027pN) reactions that have been used at Jefferson Lab to probe this short-distance structure as well as provide an outlook for future experiments. | 161,671 |
title: Higgs boson mass from t-b-τ Yukawa unification; abstract: We employ the Yukawa coupling unification condition, y\n t = y\n b = y\n τ at M\n GUT, inspired by supersymmetric SO(10) models, to estimate the lightest Higgs boson mass as well as masses of the associated squarks and gluino. We employ non-universal soft masses, dictated by SO(10) symmetry, for the gauginos. Furthermore, the soft masses for the two scalar Higgs doublets are set equal at M\n GUT, and in some examples these are equal to the soft masses for scalars in the matter multiplets. For μ \u003e 0, M\n 2 \n \u003e 0, where M\n 2 denotes the SU(2) gaugino mass, essentially perfect t-b-τ Yukawa unification is possible, and it predicts a Higgs mass of 122-124 GeV with a theoretical uncertainty of about ±3 GeV. The corresponding gluino and the first two family squarks have masses ≳ 3 TeV. We present some LHC testable benchmark points which also show the presence of neutralino-stau coannihilation in this scenario. The well-known MSSM parameter tan β ≈ 47. | 161,672 |
title: Aspects of the super-unification of strong, electroweak and gravitational interactions; abstract: Abstract We develop a strategy for extracting low-energy phenomenological four-dimensional physics from the superstring. We discuss supersymmetry and gauge symmetry breaking, emphasizing key ingredients in the construction of a realistic model based on Calabi-Yau compactification. The incorporation of a no-scale mechanism for the dynamical generation of the electroweak gauge hierarchy imposes a unique choice of the gauge group SU(3) × SU(2) × U(1)2, an almost unique set of matter fields and of Yukawa couplings. Our phenomenological analysis of this model includes the derivation of bounds on the mass of the new neutral gauge boson from the Z0 boson mass, low-energy neutral currents, and cosmology. We calculate the ratios of sparticle masses and give estimates of their magnitudes. These are based on detailed dynamical calculations demonstrating the feasibility of weak gauge symmetry breaking, made possible by radiative corrections to supersymmetry breaking initiated by a gaugino mass. | 161,673 |
title: Curing the self-force runaway problem in finite-difference integration; abstract: The electromagnetic self-force equation of motion is known to be afflicted by the so-called runaway problem. A similar problem arises in the semiclassical Einstein\u0027s field equation and plagues the self-consistent semiclassical evolution of spacetime. Motivated to overcome the latter challenge, we first address the former (which is conceptually simpler), and present a pragmatic finite-difference method designed to numerically integrate the self-force equation of motion while curing the runaway problem. We restrict our attention here to a charged point-like mass in a one-dimensional motion, under a prescribed time-dependent external force $F_{ext}(t)$. We demonstrate the implementation of our method using two different examples of external force: a Gaussian and a Sin^4 function. In each of these examples we compare our numerical results with those obtained by two other methods (a Dirac-type solution and a reduction-of-order solution). Both external-force examples demonstrate a complete suppression of the undesired runaway mode, along with an accurate account of the radiation-reaction effect at the physically relevant time scale, thereby illustrating the effectiveness of our method in curing the self-force runaway problem. | 161,674 |
title: Design and operation of spin valve sensors; abstract: Two types of patterned, unshielded Giant MagnetoResistance (GMR) spin valve sensors have been fabricated: nano-layered NiFe/Co/Cu/Co/NiFe and simpler NiFe/Cu/Co spin valves. GMR values of 7.6% for /spl Delta/H=10 Oe were measured for the nano-layered structures on coupons. Transfer curves in uniform fields were obtained and were in agreement with theoretical expectations. The sensors were highly linear and well biased. Optimum biasing of the free layer in the spin valve sensor has new features over that in AMR sensors. These were explored in shielded as well as unshielded spin valves using micromagnetic simulation. \u003e | 161,675 |
title: Diffuse phase transition of BST thin films in the microwave domain; abstract: Ferroelectric materials are widely used in the paraelectric phase in order to realize tunable capacitors with reduced losses and low hysteresis effect. Nevertheless, for polycrystalline thin films, the ferro/paraelectric phase transition can be diffuse and some crystallites can exhibit a ferroelectric nature even if the sample seem to be globally in a paraelectric phase. In this case, domain wall motions are responsible for the sensitivity of the dielectric properties to the driving field and are very dissipative phenomena. In this paper, we evaluate, in the high-frequencies band, the ferroelectricity impact on the properties of BST thin films near the phase transition, by measuring the film\u0027s dielectric properties as a function of the incident RF power and for different temperatures. | 161,676 |
title: Brane new world; abstract: Some theorists propose that our Universe exists as a slice through multidimensional space. Could this \u0027brane-world\u0027 concept unify gravity with nature\u0027s other fundamental forces? Roland Pease reports. | 161,677 |
title: Reliability of individual differences in degraded speech perception.; abstract: Listeners\u0027 speech perception abilities vary extensively in challenging listening conditions. There is little evidence as to whether this variability is a result of true, stable individual differences or just variability arising from measurement error. This study examines listeners’ word recognition abilities across multiple sessions and a variety of degraded speech tasks (noise-vocoded, time-compressed, and speech in babble noise). Participants transcribed isolated single syllable words presented in all three degradation types and repeated these tasks (with different words) on a separate day. Correlations of transcription accuracy demonstrate that individual differences in performance are reliable across sessions. In addition, performance on all three degradation types was correlated. These results suggest that differences in performance on degraded speech perception tasks for normal hearing listeners are robust and that there are underlying factors that promote the ability to understand degraded speech r... | 161,678 |
title: Ghost condensation and a consistent infrared modification of gravity; abstract: We propose a theoretically consistent modification of gravity in the infrared, which is compatible with all current experimental observations. This is an analog of the Higgs mechanism in general relativity, and can be thought of as arising from ghost condensation — a background where a scalar field has a constant velocity, = M2. The ghost condensate is a new kind of fluid that can fill the universe, which has the same equation of state, ρ = −p, as a cosmological constant, and can hence drive de Sitter expansion of the universe. However, unlike a cosmological constant, it is a physical fluid with a physical scalar excitation, which can be described by a systematic effective field theory at low energies. The excitation has an unusual low-energy dispersion relation ω2 ~ 4/M2. If coupled to matter directly, it gives rise to small Lorentz-violating effects and a new long-range 1/r2 spin dependent force. In the ghost condensate, the energy that gravitates is not the same as the particle physics energy, leading to the possibility of both sources that can gravitate and anti-gravitate. The newtonian potential is modified with an oscillatory behavior starting at the distance scale MPl/M2 and the time scale MPl2/M3. This theory opens up a number of new avenues for attacking cosmological problems, including inflation, dark matter and dark energy. | 161,679 |
title: STUDIES OF SUPERDENSE HADRONIC MATTER IN A RELATIVISTIC TRANSPORT MODEL; abstract: Transport models have been very useful in studying the properties of the hot, dense matter that is created in relativistic heavy-ion collisions. We review here a Relativistic Transport (ART) Model and its applications in heavy ion collisions at beam energies below about 10 AGeV available from the Alternating Gradient Synchrotron at Brookhaven National Laboratory. The model allows one to study not only the reaction dynamics leading to the formation of superdense hadronic matter, but also to explore the effects due to the nuclear equation of state and the deformation/orientation of the colliding nuclei on the size and lifetime of the superdense matter. We also discuss the dependence of the central baryon and energy densities, the degree of thermalization, and the collective radial flow velocity of the superdense matter on the beam energy. We further review how the properties of the superdense hadronic matter can be determined from studying the collective flow of nucleons, pions and kaons in these collisions... | 161,680 |
title: Studying the Composition and Phase State of Thin PZT Films Obtained by High-Frequency Magnetron Sputtering under Variation of Working Gas Pressure; abstract: Variation of the working gas pressure (from 8 to 2 Pa) during RF magnetron sputtering deposition of thin perovskite lead zirconate titanate (PZT) films revealed strong changes in their lead content, which decreased below the stoichiometric level and led to the formation of a two-phase (perovskite–pyrochlore) structure upon subsequent high-temperature annealing. Measurements of the composition of perovskite islands in the two-phase films showed that the lead content in these islands was equal to or greater than stoichiometric. These results lead to the conclusion that the obtained PZT films are free of lead vacancies. | 161,681 |
title: Performance of $\tau$-lepton reconstruction and identification in CMS; abstract: The performance of tau-lepton reconstruction and identification algorithms is studied using a data sample of proton-proton collisions at sqrt(s)=7 TeV, corresponding to an integrated luminosity of 36 inverse picobarns collected with the CMS detector at the LHC. The tau leptons that decay into one or three charged hadrons, zero or more short-lived neutral hadrons, and a neutrino are identified using final-state particles reconstructed in the CMS tracker and electromagnetic calorimeter. The reconstruction efficiency of the algorithms is measured using tau leptons produced in Z-boson decays. The tau-lepton misidentification rates for jets and electrons are determined. | 161,682 |
title: CANCELLATION OF ULTRA-VIOLET INFINITIES IN ONE LOOP GRAVITY; abstract: Quantization of gravity is a formidable challenge for modern theoretical physics. Ultraviolet divergencies are the problem. In 1974 the author used functional integral formalism for the quantization. The background formulation helped to solve the problem in one loop approximation. The author proved that the divergencies cancel on mass shell, because of Einstein\u0027s equations of motion. | 161,683 |
title: MAPPING THE SHORES OF THE BROWN DWARF DESERT. II. MULTIPLE STAR FORMATION IN TAURUS-AURIGA; abstract: We have conducted a high-resolution imaging study of the Taurus-Auriga star-forming region in order to characterize the primordial outcome of multiple star formation and the extent of the brown dwarf desert. Our survey identified 16 new binary companions to primary stars with masses of 0.25-2.5 M_☉, raising the total number of binary pairs (including components of high-order multiples) with separations of 3-5000 AU to 90. We find that ~2/3-3/4 of all Taurus members are multiple systems of two or more stars, while the other ~1/4-1/3 appear to have formed as single stars; the distribution of high-order multiplicity suggests that fragmentation into a wide binary has no impact on the subsequent probability that either component will fragment again. The separation distribution for solar-type stars (0.7-2.5 M_☉) is nearly log-flat over separations of 3-5000 AU, but lower-mass stars (0.25-0.7 M_☉) show a paucity of binary companions with separations of ≳200 AU. Across this full mass range, companion masses are well described with a linear-flat function; all system mass ratios (q = M_(B) /M_(A)) are equally probable, apparently including substellar companions. Our results are broadly consistent with the two expected modes of binary formation (free-fall fragmentation on large scales and disk fragmentation on small scales), but the distributions provide some clues as to the epochs at which the companions are likely to form. | 161,684 |
title: Orbital Decay and Evidence of Disk Formation in the X-ray Binary Pulsar OAO 1657-415; abstract: OAO 1657-415 is an eclipsing X-ray binary wind-fed pulsar that has exhibited smooth spin-up/spin-down episodes and has undergone several torque reversals throughout its long history of observation. We present a frequency history spanning nearly 19 years of observations from the Burst and Transient Source Experiment (CGRO/BATSE) and from the Gamma-Ray Burst Monitor (Fermi/GBM). The analysis suggests two modes of accretion: one resulting in steady spin-up during which we believe a stable accretion disk is present and one that results in what appears to be a random walk in spin frequency where an unstable accretion disk forms alternating in direction (\"flip flop\"). Orbital elements of the pulsar system are determined at several intervals throughout this history. With these ephemerides, statistically significant orbital decay ($\\dot{P}/P =(-3.40 \\pm0.15)\\times10^{-6} \\mathrm{yr^{-1}}$) is established suggesting a transition between wind-fed and disk-mediated accretion. | 161,685 |
title: Envelope overshooting in low-metallicity intermediate- and high-mass stars: a test with the Sagittarius dwarf irregular galaxy; abstract: We check the performance of the {\\sl\\,PARSEC} tracks in reproducing the blue loops of intermediate age and young stellar populations at very low metallicity. We compute new evolutionary {\\sl\\,PARSEC} tracks of intermediate- and high-mass stars from 2\\Msun to 350\\Msun with enhanced envelope overshooting (EO), EO=2\\HP and 4\\HP, for very low metallicity, Z=0.0005. The input physics, including the mass-loss rate, has been described in {\\sl\\,PARSEC}~V1.2 version. By comparing the synthetic color-magnitude diagrams (CMDs) obtained from the different sets of models with envelope overshooting EO=0.7\\HP (the standard {\\sl\\,PARSEC} tracks), 2\\HP and 4\\HP, with deep observations of the Sagittarius dwarf irregular galaxy (SagDIG), we find an overshooting scale EO=2\\HP to best reproduce the observed loops. This result is consistent with that obtained by \\citet{Tang_etal14} for Z in the range 0.001-0.004. We also discuss the dependence of the blue loop extension on the adopted instability criterion and find that, contrary to what stated in literature, the Schwarzschild criterion, instead of the Ledoux criterion, favours the development of blue loops. Other factors that could affect the CMD comparisons such as differential internal extinction or the presence of binary systems are found to have negligible effects on the results. We thus confirm that, in presence of core overshooting during the H-burning phase, a large envelope overshooting is needed to reproduce the main features of the central He-burning phase of intermediate- and high-mass stars. | 161,686 |
title: Quantum storage of heralded polarization qubits in birefringent and anisotropically absorbing materials.; abstract: Storage of quantum information encoded into heralded single photons is an essential constituent of long-distance quantum communication based on quantum repeaters and of optical quantum information processing. The storage of photonic polarization qubits is, however, difficult because many materials are birefringent and have polarization-dependent absorption. Here we present a simple scheme that eliminates these polarization effects, and we demonstrate it by storing heralded polarization qubits into a solid-state quantum memory. The quantum memory is implemented with a biaxial yttrium orthosilicate (Y2SiO5) crystal doped with rare-earth ions. Heralded single photons generated from a filtered spontaneous parametric down-conversion source are stored, and quantum state tomography of the retrieved polarization state reveals an average fidelity of 97.5±0.4%, which is significantly higher than what is achievable with a measure-and-prepare strategy. | 161,687 |
title: Radiation hydrodynamics with neutrinos - Variable Eddington factor method for core-collapse supernova simulations; abstract: Neutrino transport and neutrino interactions in dense matter play a crucial role in stellar core collapse, supernova explosions and neutron star formation. Here we present a detailed description of a new numerical code for treating the time and energy dependent neutrino transport in hydrodynamical simulations of such events. The code is based on a variable Eddington factor method to deal with the integro-differential character of the Boltzmann equation. The moments of the neutrino distribution function and the energy and lepton number exchange with the stellar medium are determined by iteratively solving the zeroth and first order moment equations in combination with a model Boltzmann equation. The latter is discretized on a grid of tangent rays. The integration of the transport equations and the neutrino source terms is performed in a time-implicit way. In the present version of the program, the transport part is coupled to an explicit hydrodynamics code which follows the evolution of the stellar plasma by a finite-volume method with piecewise parabolic interpolation, using a Riemann solver to calculate the hydrodynamic states. The neutrino source terms are implemented in an operator-split step. Neutrino transport and hydrodynamics can be calculated with different spatial grids and different time steps. The structure of the described code is modular and offers a high degree of flexibility for an application to relativistic and multi-dimensional problems at different levels of refinement and accuracy. We critically evaluate results for a number of test cases, including neutrino transport in rapidly moving stellar media and approximate relativistic core collapse, and suggest a path for generalizing the code to be used in multi-dimensional simulations of convection in neutron stars and supernovae. | 161,688 |
title: Signatures of a hidden cosmic microwave background.; abstract: If there is a light Abelian gauge boson gamma\u0027 in the hidden sector its kinetic mixing with the photon can produce a hidden cosmic microwave background (HCMB). For meV masses, resonant oscillations gamma gamma\u0027 happen after big bang nucleosynthesis (BBN) but before CMB decoupling, increasing the effective number of neutrinos Nnu(eff) and the baryon to photon ratio, and distorting the CMB blackbody spectrum. The agreement between BBN and CMB data provides new constraints. However, including Lyman-alpha data, Nnu(eff) \u003e 3 is preferred. It is tempting to attribute this effect to the HCMB. The interesting parameter range will be tested in upcoming laboratory experiments. | 161,689 |
title: The influence of thermal stresses on the phase composition of 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 thick films; abstract: The influence of thermal stresses versus the phase composition for 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (0.65PMN–0.35PT) thick films is being reported. The thermal residual stresses in the films have been calculated using the finite-element method. It has been observed that in 0.65PMN–0.35PT films a compressive stress enhances the thermodynamic stability of the tetragonal phase with the space group P4mm. | 161,690 |
title: Direct Assessment of Vorticity Alignment with Local and Nonlocal Strain Rates in Turbulent Flows; abstract: A direct Biot-Savart integration is used to decompose the strain rate into its local and nonlocal constituents, allowing the vorticity alignment with the local and nonlocal strain rate eigenvectors to be investigated. These strain rate tensor constituents are evaluated in a turbulent flow using data from highly-resolved direct numerical simulations. While the vorticity aligns preferentially with the intermediate eigenvector of the \\textit{combined} strain rate, as has been observed previously, the present results for the first time clearly show that the vorticity aligns with the most extensional eigenvector of the \\textit{nonlocal} strain rate. This in turn reveals a significant linear contribution to the vortex stretching dynamics in turbulent flows. | 161,691 |
title: Measurement of electrostrictive coefficients of polymer films; abstract: A new technique to experimentally determine the electrostrictive coefficients of thin polymer films is presented. This technique is a second-order extension of the first-order quasistatic method for the measurement of piezoelectric coefficients previously introduced by Guillot and Jarzynski [J. Acoust. Soc. Am. 108, 600–607 (2000)]. In the present method, electrically induced strains are measured optically on a rubber-encapsulated sample. These strains are used in a Rayleigh–Ritz procedure that minimizes the total energy of the sample and whose output is a set of three tensile electrostrictive coefficients. The total energy of the sample includes elastic contributions from the polymer and the encapsulating rubber as well as two quadratic electromechanical terms corresponding to Maxwell stress and to electrostriction. Therefore, the external electrostatic effects can be separated from the intrinsic electrostrictive behavior, and the measured coefficients are true material properties. Data obtained on two t... | 161,692 |
title: Specific features in the permittivity of polycrystalline ferroelectrics: The role of Schottky regions; abstract: This paper reports on the results of investigations into the influence of Schottky regions formed in the vicinity of crystallite boundaries in polycrystalline ferroelectrics on their permittivity. The dependence of the dielectric properties of the Schottky regions on the orientation of the spontaneous polarization in the adjacent region of the crystallite is taken into consideration. It is demonstrated that nonmonotonic dependences of the permittivity and its relative change on the crystallite size under uniaxial compression are associated with the presence of the domain structure in polycrystalline ferroelectrics. | 161,693 |
title: Test of a General Formula for Black Hole Gravitational Wave Kicks; abstract: Although the gravitational wave kick velocity in the orbital plane of coalescing black holes has been understood for some time, apparently conflicting formulae have been proposed for the dominant out-of-plane kick, each a good fit to different data sets. This is important to resolve because it is only the out-of-plane kicks that can reach more than 500 km s–1 and can thus eject merged remnants from galaxies. Using a different ansatz for the out-of-plane kick, we show that we can fit almost all existing data to better than 5%. This is good enough for any astrophysical calculation and shows that the previous apparent conflict was only because the two data sets explored different aspects of the kick parameter space. | 161,694 |
title: Observation of electron transport in polyethylene terephthalate and the radiation hardening of dielectrics; abstract: Electron‐induced conductivity measurements were performed on polyethylene terephthalate to compare electron and hole contributions to the radiation‐induced conductivity. The electron mobility in this material was found to be ≳102 times that of the holes. This result explains an earlier observation that the radiation‐induced conductivity of polyethylene terephthalate can be radically reduced by chemically doping this dielectric with electron acceptor molecules. | 161,695 |
title: Reinvestigation of Quark Masses Variations on Big Bang Nucleosynthesis; abstract: We report the constraints from primordial nucleosynthesis on a possible time-dependent quark mass. The variation may affect binding energies and Q values as well as resonance properties of light elements through the hadron mass variation in the nucleon–nucleon interaction. Updated light-element abundances and uncertainties along with a new detailed analysis of the resonance properties on the crucial 3He(d, p)4He reaction imply a narrower range on the possible quark-mass variations in the early universe. The optimum concordance region reduces to a value consistent with no variation. | 161,696 |
title: Search for quark contact interactions and extra spatial dimensions using dijet angular distributions in proton-proton collisions at √s = 8 TeV; abstract: ©2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3. | 161,697 |
title: Abnormal variation of band gap in Zn doped Bi0.9La0.1FeO3 nanoparticles: Role of Fe-O-Fe bond angle and Fe-O bond anisotropy; abstract: Bi0.9La0.1FeO3 (BLFO) and Bi0.9La0.1Fe0.99Zn0.01O3 (BLFZO) nanoparticles were prepared via a sol-gel method. The oxygen vacancies and holes increase with Zn doping analyzed through X-ray photoelectron spectroscopy, which could contribute to the increase of leakage current density. However, with the increase of the defects (oxygen vacancies and holes), the band gap of BLFZO also is increased. To explain the abnormal phenomenon, the bandwidth of occupied and unoccupied bands was analyzed based on the structural symmetry driven by the Fe-O-Fe bond angle and Fe-O bond anisotropy. | 161,698 |
title: Theoretical aspects of science with radioactive nuclear beams; abstract: Physics of radioactive nuclear beams is one of the main frontiers of nuclear science today. Experimentally, thanks to technological developments, we are on the verge of invading the territory of ex... | 161,699 |
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