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S002236971931916X
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Oxidizing graphite to graphene oxide through non explosive oxidizing mixture at 55C is reported with high yield . GO was anchored with NiS ZnS and CdS metallic sulfide nanoparticles in 1 1 ratio at 85C . MSNPs were obtained by using chloride salts of Ni Zn and Cd metals with thiourea in 1 3 ratio in aqueous GO for
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Graphite was functionalized to graphene oxide. GO had. anchored metallic sulfide nanoparticles. MSNP GO had reduced 97 methylene blue. Intersheet distance in GO increased compared to Gt. Intersheet vander Waals forces accommodated MSNPs.
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S0022369719319341
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The aim of this work has been to improve the time resolution of radiation detectors for future high energy physics experiments and medical imaging applications . Ce doped oxyorthosilicate Lu
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The time resolution of LYSO is more affected by carrier trapping than that of LSO. Carrier trapping in LYSO is enhanced by fluctuations in the compound composition. Ca co doping even at a concentration of 5ppm improves the response time of LYSO Ce. Femtosecond pump probe spectroscopy is a useful tool for improving Ce doped scintillators.
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S0022369719319390
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Striking photo induced voltage is observed in YBCO Ag heterojunction irradiated with purple laser revealing that there is an intrinsic built in electric field in the interface . The dynamic evolution and devolution processes of the photo induced voltage are studied at 50K and 300K respectively which are found to be similar to a charging and a discharging process of a plate capacitor . Unusual Current Voltage properties curves obtained at 80K with 28.4mW mm
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Striking photo induced voltage is observed in YBCO Ag heterojunction irradiated with purple laser. The dynamic evolution and devolution processes of the photo induced voltage. Unusual. curve witnesses a polarity switching of the built in electrical field in the interface.
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S0022369719319407
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Electrochemical properties of porous nickel foam electrodeposited zinc on Ni foam and electrodeposited reduced graphene oxide on NiZn foam electrodes in 6M KOH electrolyte were investigated . Cyclic voltammetry and galvanostatic chargedischarge cycling techniques were used to carry out the redox interactions and cycling capacitive properties of the electrodes in KOH solution . Platinum and gold foil were used as a counter electrode and the current collector in the electrochemical measurements respectively . The specific capacitances of the electrodes were found from the GCD measurements as 155 722 and 1820F g for Ni NiZn and NiZn rGO electrodes at the current density of 1 A g respectively . Scanning electron microscope images of the three electrodes were also taken into account to associate all the electrochemical measurements . These results clearly show that specific capacitance values highly increased after the deposition of Zn and rGO to Ni electrode .
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Reinforced electrodes for supercapacitor applications. Electrical deposition of zinc and graphene oxide. Remarkable improvement of the energy and power densities. Low retention and high cycling performance
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S0022369719319432
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The coherent potential approximation is applied to study the evolution of the electronic structure mainly in the vicinity of the energy gap of pure corundum Al
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Changes of energy spectrum characteristics due to contributions of. impurities and vacancy states inside the energy gap of undoped Al. are studied by the coherent potential approximation. Compositions of Al. based compounds with energy gap width comparable with visible range of solar spectrum are proposed for applications in photocatalysis and optical devices.
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S0022369719319572
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According to Vegard s law larger radius atoms substitute for smaller atoms in a solid solution would enlarge the lattice parameters . However by first principles calculations we have observed unusual lattice shrinkage when W replaces Ge in rock salt GeTe . We attribute this anomalous contract to the larger electronegativity difference between W and Te than between Ge and Te which results in shorter WTe bonds and pronounced local distortion around W dopants . The present work would provide new insight into the lattice parameter determination and a deeper understanding of the structural properties of ternary solid solutions .
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Anomalous lattice shrinkage has been observed when smaller Ge in rock salt GeTe is replaced by larger W. The larger electronegativity difference between W and Te than between Ge and Te results in shorter WTe bonds. Shorter WTe bonds reduced lattice parameters and induced pronounced local distortion around W dopants. Electronegativity difference between dopant and host atoms is crucial in determining lattice parameters of complex alloys.
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S0022369719319584
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A novel green tea extractencapsulated silica gel decorated with in situgenerated Pd nanoparticles is reported as an efficient green heterogeneous catalyst in the Buchwald Hartwig CN cross coupling reaction . It was characterized by several analytical techniques . Thereafter a wide range of aryl amines were synthesized in good to excellent yields by reaction of different substituted aryl halides and secondary amines over the catalyst . The material is sufficiently stable and could be used at least six times in a model Buchwald Hartwig reaction without noticeable change in its catalytic activity . Heterogeneity of the catalyst was examined by a hot filtration test .
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In situgenerated palladium nanoparticles anchored to green tea extractcoated silica gel. Excellent performance as a reusable catalyst in Buchwald Hartwig CN cross coupling reactions. Excellent yield of the products. Catalyst used up to six times.
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S0022369719319596
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The thermodynamic stability of Bi containing III V quaternary alloys was determined using the delta lattice parameter model in conjunction with density functional theory calculations . The DLP model and DFT calculated enthalpy of mixing show remarkably good agreement for the In
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The thermodynamic stability of Bi containing III V quaternary alloys was determined using theDLP and DFT approaches. Binodal and spinodal isotherm contours are presented for Bi based quaternary systems as a function of strain state. Incorporation of an anion element with a smaller atomic size also increases the Bi solubility in the Bi low concentration regime. Elucidates the thermodynamic stability dependence for Bi containing quaternary alloys on choice of cation anion and strain state.
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S0022369719319638
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Chiral integer quantum Hall edge modes are immune to backscattering and therefore are non localized and show a vanishing longitudinal as well as non local resistance along with quantized 2 terminal and Hall resistance even in presence of sample disorder . However this is not the case for contact disorder which refers to the possibility that a contact can reflect edge modes either partially or fully . This paper shows that when all contacts are disordered in a N terminal quantum Hall bar then transport via chiral QH edge modes can have a significant localization correction . The Hall and 2 terminal resistance in an N terminal quantum Hall sample deviate from their values derived while neglecting the phase acquired at disordered contacts and this deviation is called the quantum localization correction . This correction term increases with the increase of disorderedness of contacts but decreases with the increase in number of contacts in an N terminal Hall bar . The presence of inelastic scattering however can completely destroy the quantum localization correction .
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In a 2DEG at high magnetic fields and low temperatures chiral spin unpolarized quantum Hall QH edge modes exist. These QH edge modes are chiral dissipation less and robust against disorder and therefore highly promising candidates for use in low power information processing. We identify a crucial distinction between a QH sample with all N contacts disordered and that with less than N say 1 2 or N 1 contacts disordered. We predict that for a QH sample with all N contacts disordered a quantum localization correction term comes into being due to interference. We term this correction to the resistances as quantum localization to distinguish it from weak localization arising in quantum diffusive transport.
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S0022369719319705
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Interest in the application of thermoelectric devices for renewable energy has risen over the past decade . In this paper we calculate the transport properties of various configurations of the transition metal dichalcogenide MSe
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We evaluate the thermoelectric promise of the MSe. M Ti Hf Zr monolayers. We evaluate strain and the creation of heterostructures for thermoelectric enhancement. We find a new heterostructure with remarkable thermopower at low temperatures. We propose promising materials with high thermoelectric performance at low high temperatures.
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S0022369719319730
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In this study alternative transparent amorphous borosilicate glass systems incorporating metal oxides comprising PbO BaO and SrO at different concentrations were tested as gamma ray shielding materials . The mass attenuation coefficients
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Borosilicate glasses prepared with PbO BaO and SrO at various concentrations. Gamma ray shielding properties of borosilicate glasses investigated. Mass attenuation coefficients calculated for borosilicate glass samples. Environmentally friendly gamma ray shielding materials identified. Glasses doped with high concentrations had higher densities and lower HVL values.
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S0022369719319870
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We present experimental and first principles studies of the lattice dynamics of the recently discovered new compounds La
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Ln. CrGe. Be. Ln La Pr Nd constitute a new class of low dimensional antiferromagnets. Observed vibrations of Ln. CrGe. Be. point to the langasite structure. Both Raman and IR modes are uniformly distributed over the spectral range 80840cm. The spectra are well simulated by DFT calculations with the B3LYP hybrid functional.
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S0022369719320013
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In the present study a monocrystalline silicon wafer was treated by ultrasonic nanocrystal surface modification to enhance the efficiency and service life of Si based devices by reducing reflectivity and improving surface properties respectively . Microstructure surface reflection surface free energy and dry tribological characteristics of Si wafer before and after UNSM were systematically investigated . A silicon nitride Si
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Si wafer with a thickness of about 279m was treated by UNSM. Surface roughness and hardness were increased by 400 and 14 respectively. Reflectivity of Si wafer reduced at throughout wavelength after UNSM. Tribological characteristics were improved after UNSM. The average grain size after UNSM was found to be about 50nm.
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S0022369719320293
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Preparation of PbTe based ternary chalcogenide nanowires with controllable phases and thermoelectric properties still faces challenges . Hereby we employ a solution approach to synthesis highly uniform PbTe
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A solution approach to synthesis phase controllable ultrathin PbTe. Se. nanowires. The phases of the products were highly governed by the dosage of KOH. Nano sized PbTe. Se. matrix maintains relative low lattice thermal conductivity.
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S002236971932030X
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Sunlight driven photocatalysis is the next step of environmental remediation which can utilize the renewable energy to cure environmental problems . Herein we report a magnetically recoverable ZnS Ag CoFe
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Magnetically recoverable ZnS Ag CoFe. nanocomposite photocatalyst were synthesized by simple wet precipitation method. ZnS Ag CoFe. nanocomposite exhibit high stability for successive cycles with enhanced photocatalytic performance against MB RhB dyes. The antibacterial activity of the ZnS Ag CoFe. nanocomposite showed better antibacterial activity as compared to CoFe. NPs and Ag CoFe. samples.
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S0022369719320426
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In this study neodymium doped BiOBr nanosheets were synthesized using a hydrothermal method for the first time . The optical and physicochemical properties of the samples were examined using different characterization techniques . X ray diffraction energy dispersive X ray and X ray photoelectron spectroscopy analyses confirmed that the Nd ion was successfully doped into BiOBr . The visible light absorptivity increased as the Nd content of the BiOBr increased according to ultravioletvisible diffuse reflectance spectroscopy analysis . The as synthesized Nd BiOBr samples were effectively used to photodegrade palm oil mill effluent under visible light irradiation . In particular 3.0at Nd BiOBr boosted the photocatalytic performance compared with other photocatalysts . The enhanced effectiveness was attributed to the improved separation of the photogenerated charge carriers and the formation of abundant hydroxyl radicals according to photocurrent response and photoluminescence analyses . Moreover Nd BiOBr exhibited excellent stability and it could be reused for several cycles without any significant loss of the catalytic activity . The phytotoxic effects of POME against the germination of
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Surfactant free hydrothermal synthesis of novel Nd doped BiOBr nanosheets. Structural optical and morphological characterization of as synthesized samples. Nd BiOBr exhibited enhanced POME photodegradation with good reusability. Effective inactivation of. over Nd BiOBr under visible light irradiation. Nd doping effectively trapped electrons and promoted separation of charge carriers.
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S0022369719320943
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In this study a simple hydrothermal method was used to prepare flower like zinc oxide which was then combined with biomass hollow carbon derived from rice husk under hydrothermal conditions to obtain a ZnO RHC composite material . The ZnO RHC composite was used as the anode in lithium ion batteries and it exhibited excellent electrochemical performance and cycling stability due to its special microstructure . In the ZnO RHC composite the sheet structure comprising zinc oxide was coated on the biomass carbon layer of the hollow spherical structure to form numerous conductive networks thereby improving the electrochemical properties of the ZnO RHC . The composite provided a reversible specific capacity of 1002.5mAh g
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Simple hydrothermal method used to prepare flower like zinc oxide. Flower like ZnO combined with rice husk derived hollow carbon to obtain ZnO RHC. ZnO RHC obtained good electrochemical performance as anode in lithium ion battery.
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S0022369719321195
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We present the chemical surfactant mediated and green surfactant mediated synthesis of manganese oxide nanoparticles prepared by the precipitation method using cetyltrimethylammonium bromide and tea extract respectively and their structural and optical properties . The nanoparticles were characterized by X ray diffraction scanning electron microscopyenergy dispersive X ray analysis UVVis spectroscopy and Fourier transform IR spectroscopy with regard to the diffraction pattern phase size shape composition of material etc . The Mn
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Manganese III oxide is synthesized with manganese acetate tetrahydrate as a precursor. The green surfactant assisted precipitation method uses chemical free tea grain extract as a surfactant. The efficiency and properties of the green synthesized and chemically synthesized nanoparticles are compared. The nanoparticles have well defined cubic and spherical shapes with sizes of 2050nm. Antimicrobial activity oxidative transformation and removal of pollutants from water by photodegradation are studied.
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S0022369719321298
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Due to the fact that the melting process of nanomaterials is carried out with the continuous change of melting temperature previous equations of differential melting enthalpy and entropy are unable to reflect their thermodynamic behaviors of actual melting process . On the basis of our previous work theoretical calculations were conducted on the size and morphology dependent integral melting enthalpy and entropy of nano sized Au Ag and Sn and reasonable agreements with experimental results were observed . In addition the integral melting enthalpy and entropy were also compared with the corresponding differential quantities . The differences between integral and differential melting enthalpy are mainly determined by the surface area and the interfacial tension and the melting entropy by the surface area and the temperature coefficient of interfacial tension . The findings are able to deepen our understanding of the size and morphology dependent melting thermodynamics of nanomaterials and to further develop the thermodynamic theory of phase transitions of nanomaterials .
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Quantitative influence regularities of particle size and morphology on. and. of nanomaterials were investigated. Theoretical results on. and. of nanomaterials present reasonable agreements with experimental results. Comparisons were made for integral melting enthalpy and entropy with corresponding differential quantities.
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S0022369719321481
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Lithium doped ZnO structures with sizes in the micro and nano scale and different morphologies were obtained by vaporsolid growth method . Two different precursors lithium oxide and lithium carbonate were used as the lithium source in order to study the influence on the morphology and optical properties of the obtained structures . Scanning electron microscopy cathodoluminescence photoluminescence X ray diffraction energy dispersive X ray microanalysis and Raman spectroscopy were used to characterize their structure morphology composition and optical properties . Depending on the lithium content present changes in the crystalline quality and the luminescent intensity of the samples were observed . Optical resonant cavity behavior was also observed in some of the nano structures .
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ZnO Li structures were obtained by a vaporsolid method. The amount of defects produced by Li were related to the luminescence emission. An optical resonant cavity behavior was observed in some of the nanostructures.
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S0022369719321663
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In this study we use the operator projection method and descriptions of the FuchsKliewer Ridley and HuangZhu confined phonon models to investigate the influence of confined optical phonons on the magneto optical properties in parabolic quantum wells by calculating the expression for the absorption power . The full width at half maximum is obtained for the cyclotron resonance peak by using a computational method . The FWHM is defined as functions of the confinement frequency temperature and magnetic field for both the bulk phonon and confined phonon models . The results are discussed and compared with those for square quantum wells . The results show that the FWHM has a larger value in the parabolic quantum wells and it varies more rapidly than that in the square quantum wells for both the bulk phonon and confined phonon models . Thus phonon confinement has an important role and it should be considered when investigating the FWHM for parabolic quantum wells .
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Cyclotron resonance of the full width at half maximum CRFWHM calculated. CRFWHM increases with magnetic field temperature and confinement frequency. CRFWHM value larger for confined phonon than bulk phonon. CRFWHM values smallest for Ridley model but largest for Huang Zhu model. CRFWHM value larger for parabolic quantum wells than square quantum wells.
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S0022369719321791
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The phase transition boundary between the zinc blende and the rock salt structure in zinc selenide was determined using high pressure experiments combined with the synchrotron X ray diffraction technique . Significant hysteresis in the phase transition was not observed at high temperatures . The transition pressure was extrapolated to be 13.3GPaat 300K and the
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The semiconductormetal phase boundary in zinc selenide has negative. slope. Transition pressure is 13.3GPaat room temperature. Linear relationship between the semiconductor metal transition pressures and dP dT slopes in II VI and III V compounds were found.
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S0022369719321948
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Different rare earth doped nickel ferrites were prepared through the sol gel citrate auto combustion method . Rietveld refinement of the X ray diffraction patterns confirmed the formation of an orthorhombic impurity phase for each doped sample . Structural parameters including lattice parameter crystallite size microstrain and different bond lengths were calculated . Field emission scanning electron micrographs showed spherical grains and the existence of secondary phases for the doped samples . Elemental analysis of each component were performed using energy dispersive X ray spectra . The shifting of the absorption bands of the Fourier transform infrared spectra depicted the rare earth to Fe substitution in octahedral sites of nickel ferrites . The optical band gap decreased with the smaller ionic radii of dopants . The study of ac and dc conductivity provided information about the conduction and dielectric relaxation mechanism and the effect of impurity phases . The electrical conductivity and dielectric study suggested that La and Sm doped samples showed the highest resistivity with high losses whereas Ho and Gd doped samples showed moderate resistivity with minimum losses .
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Citrate auto ignition is used to synthesize rare earth RE doped nickel ferrite. RE ions are found to replace Fe ions predominantly in octahedral sites. Optical bandgap decreases with increase in cation radii of dopants. The impurity phases play crucial roles in conduction and dielectric relaxation. Ho and Gd doped samples stand out with high resistivity and optimum loss.
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S0022369719322218
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In this paper we proposed a sensitive load sensor probe based on microfiber resonator . The microfiber was prepared from the common single mode fiber by one step heating stretching method and used to fabricate a microfiber knot resonator by micromanipulation technique . This MKR was packaged later by polydimethylsiloxane film layer in two glass slides . The load sensing performance have been explored and compared for the bare MKR structure and PDMS packaged MKR probe . The longitudinal load sensing characteristics were experimentally demonstrated with a small sensitivity of 6 p.m. N due to the large Young s modulus and low elastooptical effect of silica materials . In order to increase the longitudinal load sensitivity and stability of bare MKR we chose PDMS to encapsulate MKR due to its small Young s modulus and large Poisson s ratio . The strain sensing performance of both a bare and PDMS packaged silica MKR were experimentally demonstrated and compared . The experiment results revealed a sensitivity of 94.5 p.m. N. The simple structure low loss and easily fabrication process pave its way to a miniature strain sensor chip .
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Strain sensor based on Silica microfiber resonator packaged by PDMS was proposed. Strain sensing performance was experimentally demonstrated. Strain sensitivity of 94.5 p.m. N has been obtained. Impact of micro ring length on sensing performance was studied.
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S002236971932236X
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Photocatalysis is a well established and green technique in environmental pollutant remediation . In the present study a novel and green red phosphorus hollow hydroxyapatite microsphere photocatalyst was fabricated and applied forthe degradation of rifampicin tetracycline and levofloxacin . The as prepared material exhibits outstanding photocatalytic activity and stability and has universal application for degradation of each antibiotic . Notably tetracycline rifampicin andlevofloxacin can be completely degraded within 10min 20min and 50min respectively under a 300W Xe lamp with full spectrum illumination where the optimal conditions were an initial pH of 6.0 and a photocatalyst dosage of 1.0g L. In addition a plausible photocatalytic reaction mechanism was proposed . The low cost highly efficient and green red phosphorus hollow hydroxyapatite microsphere photocatalyst is a promising candidate for the removal of many hazardous pollutants .
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A novel red phosphorus hollow hydroxyapatite microsphere composite was fabricated. The material is an outstanding photocatalyst for degradation of antibiotics. OH and h. are the predominant active species in the photocatalytic process. The material has potential applications in photocatalysis.
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S0022369719322437
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Microcomposites of zirconium 4 sulfophenylphosphonate and polyaniline and zirconium 4 carboxyphenylphosphonate and PANI were prepared and their thermal decomposition in air and in nitrogen was studied by thermogravimetry . The products of the decomposition of the parent zirconium phosphonates as well as the composites formed with PANI were characterized by energy dispersive X ray analysis elemental analysis powder X ray diffraction IR spectroscopy and Raman spectroscopy . Heating of the parent hosts and the composites in air to 850C leads to their total or almost total conversion to amorphous zirconium diphosphate . In nitrogen on the other hand a significant amount of carbon is retained after heating of both the hosts and the composites to 850C . The Raman spectra reveal that PANI which is present as a thin film on the host particles in the starting composites is converted to a carbon like material when it is heated in a nitrogen atmosphere . The originally crystalline phosphonates become amorphous after being heated in nitrogen which means that the heating leads to the destruction of the layered structure of these compounds . IR spectra indicate that the phosphonate particles either in the parent host or in the nanocomposites heated in nitrogen are protected against condensation to zirconium diphosphate .
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Composites of zirconium phosphonates and polyaniline were thermally decomposed. Heating of the parent hosts and the composites in air to 850C leads to conversion to amorphous ZrP. A significant amount of carbon is retained after the parent hosts and the composites have been heated to 850C in nitrogen. A thin layer of carbonized polyaniline protects the hosts from conversion to ZrP
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S002236971932325X
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To study the relationship between the properties of low dimensional spin systems with weakly coupled Cu triangles and their crystal structure single crystals of Cs
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Crystallization of a new low dimensional spin compound Cs. Cu. Cl. Br. OH with weakly coupled Cu triangles. X ray diffraction of new compound results in a monoclinic structure. 21. which is isostructural to Cs. Cu. Cl. OH.. Detection of distinct variations in the magnetic properties of both investigated compounds caused by Br doping.
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S0022369719323297
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Construction of p n heterojunction is an effective strategy to obstacle the rapid recombination of photo generated carriers for single photocatalyst . Herein visible light active Bi
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The visible light active Bi. Bi. p n junction was prepared by a one pot hydrothermal method. The in situ formed BiOCl reacts with NaBiO. 2H. O during the hydrothermal process producing Bi. Bi. p n heterojunction. Bi. Bi. heterojunctions improve the separation efficiency of charge carriers. Bi. Bi. heterojunctions exhibit improved photocatalytic degradation of MO and phenol.
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S0022369719323406
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The elemental composition of GeSe glasses prepared by different methods and the distribution of Ge and Se along the bulk sample length are investigated by inductively coupled plasma atomic emission spectrometry . The estimated uncertainty of Ge and Se content measurement is 0.020.05at .
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A technique has been developed for determining the elemental composition of Ge Se glasses and optical fibers by ICP AES. The analysis results accuracy is characterized by expanded uncertainty of 0.020.05 at. 0.95 . The chemical composition of glassy samples of Ge Se systems and optical fibers depends on the preparation method.
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S002236971932342X
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The current study aims to investigate the influence of high energy milling of nano silica and magnesium on the products of reduction reaction induced by such mechano chemical route . Collision energy driven by ball milling was calculated to enable the surveying of the level of energy on the obtained nano silicon at the room temperature and in the argon atmosphere . The phase composition analysis was conducted by the Rietveld method . Silicon products of above 97 purity were obtained in a mechanochemically synthesized system . Morphologically this route results in a mesoporous silicon nanoparticle with surface area 134.01m
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Nanostructured silicon was achieved by HBEM of rice husk derived nano silica and Mg and subsequent leaching of products. The influence of milling energy as a rapid process on microstructural properties of synthesized Si has been investigated. The raw materials are low cost and the HEBM process is facile and reproducible. Si C product exhibited a reversible specific capacity of 3113 mAh.g. at CD 0.4 A g . Electrochemical characterizations and electrical resistivity of 1.823 W.cm. reveals its potentiality as LIB anode.
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S0022369719323595
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We exploit the thermal induced dewetting process of a deposited Pt film to produce two dimensional arrays of Pt nanostructures on SiC surface .
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Nanoscale thick Pt films were deposited on 6HSiC substrate. Thermal annealing processes were performed on the Pt films. The gradual evolution of the films in nanostructures was observed. SEM AFM EDX analysis allowed to quantify the characteristics of the Pt nanostructures. The mechanisms and parameters governing the Pt nanostructures formation were elucidated.
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S0022369719323613
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We report the structural stability and compressibility behavior of 5B transition metal monoborides VB and TaB under high pressure . For the study VB was synthesized in single phase by arc melting method followed by repeated annealing treatments and intermediate grinding and TaB was procured . High pressure X ray diffraction studies were carried out using synchrotron X ray radiation up to 37.5 and 40.5GPa for VB and TaB respectively . The ambient orthorhombic lattices were stable for the monoborides in the pressure range studied . The bulk moduli were estimated to be 301 and 367 GPa respectively . The axial compressibility was highest along the
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The monoborides VB and TaB were studied under high pressure and compared. VB and TaB are highly incompressible with respective bulk moduli of 301 5 and 367 4 GPa. The compressibility behavior is consistent with the bond nature and alignment. Pseudogap in density of state plots is due to. hybridization and partial ionicity of metalB bond. Small Poisson s and Pugh ratio imply that VB and TaB are not malleable or ductile.
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S0022369719323625
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Multifunctional nanomaterials are of great technological interest due to a wide range of applications . This study reports the structure magnetic properties and electrocatalytic activity to oxygen evolution reaction of NiFe
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NiFe. NiFe. composite nanofibers prepared by solution blow spinning. Mssbauer and magnetic studies of fibrous materials at T12K. NiFe. NiFe. nanofibers as electrocatalyst for OER in alkaline medium. Nanofibers show a low overpotential of 316mV vs RHE at J 10mAcm
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S0022369719323698
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To understand the interplay between lattice structure and spin degrees of freedom a bulk Gd lattice as a hexagonal close packed structure was generated and populated with paramagnetic Gd
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Developing a numerical experiment on bulk Gd as a benchmark material for design of new magnetic refrigeration materials. Magnetic entropy magnetization magnetic specific heat magnetic susceptibility are investigated. The statistics of spin projections vs. temperature are new elements of analysis.
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S0022369719323777
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An improvement in the photocatalytic activity of lanthanum ferrite was attempted by doping individual alkaline earth elements in its La site and Mg in Fe site to get the desired energy band characteristics . All doped compositions of LaFeO
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Novel visible light absorbing alkaline earth elements doped LaFeO. nanocomposites were synthesised by sol gel method. The composite showed excellent photocatalytic hydrogen evolution and Congo red dye degradation than the phase pure materials. The secondary oxides act as co catalysts and enhance photocatalytic activity. The detailed degradation mechanism was proposed and excellent photocatalytic activity was repeated upto several cycles.
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S002236971932390X
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With the high speed development of nuclear energy radioactive contamination has attracted worldwide attention . In this study the polyacrylamide titanium dioxide composites PAM TiO
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The adsorption capacities of PAM TiO. are 146.5mg g for U VI and 38.8mg g for Eu III . The adsorption took place at the surface of PAM TiO. and did not destroy its phase structure. The existence of U VI can reduce the removal of Eu III and vice versa.
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S0022369719323911
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In this study we introduce a new approach to construct the Schrdinger equation with position dependent mass characterized by an emerging particle s effective mass in perfect analogy with the problems involving a position dependent mass particle in semiconductor heterostructures . We have discussed several of its properties and some of its implications in quantum dots and semiconductors . It was observed that the PDM approach affects only semiconductors with large interatomic scaling such as non crystalline semiconductors and its effect on conventional semiconductors is insignificant .
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A new approach to construct the Schrdinger equation with position dependent mass has been introduced. The emergence of an effective particle mass occurring in semiconductor heterostructures. Several points in quantum dots and semiconductors have been analyzed. This theory is suitable to describe non crystalline semiconductors with large interatomic scaling.
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S0022369719324370
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Raman spectra of terephthalic acid regular TPA and deuterated TPA were recorded in the temperature range of 5300K . It is shown that temperature dependences of vibration frequencies provide both the data on proton tunneling in tautomeric bonds and the data on phonon assisted proton jumps . At the same time the quantum delocalization of proton i.e . penetration of proton density distribution function into the neighboring potential well affects the temperature dependence of the frequency of translational vibrations OO and is observed at T180K in TPA and at T170K in TPA . Proton tunneling through the barrier affects the temperature dependence of the frequency of C
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Raman spectra of terephthalic acid normal and deuterated are taken in the temperature range of 5K300K. Penetration of proton density into the neighboring potential well is observed at T180K. Proton tunneling through the barrier is observed at T100K. No coordinated proton deuteron jumps over the potential barrier was observed in TPA over the entire temperature range.
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S0022369719324473
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We demonstrate that the magnetic tetrahedral structure and electronic properties of FeSe films are closely related to the in plane biaxial strain . Our calculations show that the magnetic ground state of FeSe films maintain their striped antiferromagnetic order even under biaxial compressive or tensile strain . Upon increasing the compressive strain the structure of the FeSe
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The tetrahedral and electronic properties of FeSe films can be tuned by applying in plane biaxial strain. The large distortion of the FeSe. tetrahedron form a strong Fe 3. Se 4. hybridization state. Compressive strain suppresses the antiferromagnetism of FeSe increasing the spin fluctuation.
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S0022369719324497
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Two dimensional metal carbides are attractive owing to their unique structures and promising applications . Herein we propose a one step compressive route to grow 2D iron carbide challenging the dominant exfoliation approach . First principles simulation showed that artificial compression can drive directional migration of Fe Cr and C atoms which asynchronously accumulated to form 2D hexagonal iron carbide with a stable interplanar distance of 0.39nm similar to the structure of 2D graphene . The microhardness of 2D hexagonal iron carbide was 652HV which is 1.2 times that of original orthorhombic iron carbide . Deformation of
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Two dimensional iron carbide was achieved by a one step compressive route. The microhardness of 2D hexagonal iron carbide was 652Hv which was 1.2 times that of orthorhombic iron carbide 560Hv . Collaborative deformation of Fe C and Cr C bonds is important for the orthorhombic to hexagonal evolution of iron carbide. The one step compressive route may open a new door for the controllable growth of defect free two dimensional materials.
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S0022369719324618
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Towards the malignant impact of red mud on the environment and water pollution caused by organic dyes affluent residual iron ions in red mud are recovered and converted into functional hierarchical porous Fe
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Abundant iron in red mud is hydrothermally converted into hierarchical porous Fe. microspheres. Adsorption isotherm can be well fitted with Langmuir isotherm model with the q. determined as 342.57mgg. Microspheres can be easily regenerated and reused with satisfactory chemical morphological and structural stability. Major phase of the quasi amorphous iron bearing room temperature precipitate is determined as Fe OH. Adsorption kinetic data can be well interpretated via the pseudo second order and intra particle diffusion models.
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S0022369719324655
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Supercapacitors have recently received immense interest in scientific community as a complementary technology to batteries to meet the various requirements for energy usage in practice . Amorphous MnO
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The amorphous MnO. and CuS are prepared on SS by CBD and SILAR methods respectively. Amorphous nature of materials decreases R. and R. in electrochemical studies due to surface which leads to diffusion controlled charge storage process. Potential window of 2V is achieved for asymmetric solid state SS A MnO. PVA Na. SO. A CuS SS supercapacitor device. Enhanced specific energy of 57.4Wh kg. at specific power of 0.32Wkg. is obtained for flexible asymmetric supercapacitor. The supercapacitor device shows excellent flexibility 87 and stability 84 performance.
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S0022369719324813
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Black phosphorus based two dimensional heterostructure photocatalysts have attracted much attention due to their prominent photocatalytic performance . However theoretical analysis on the mechanism of photocatalytic activity is still lacking . Firstly we comprehensively analyzed the structural and electronic properties of BP BiVO
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A type II BP BiVO. 010 heterostructure for promising photocatalytic performance is proposed. The interfacial vdW interactions and electronic properties of BP BiVO. 010 heterostructure are performed. BiVO. can be a promising candidate either as a capping or supporting layer for encapsulating BP layer.
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S0022369719324850
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High quality and sizable single crystals are essential for studying the intrinsic properties of a novel superconductor . Here for the first time we report the successful growth of millimeter size single crystals of ZrP
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Millimeter size ZrP. Se. single crystals were synthesized by using a CVT technique for the first time. Intrinsic properties are systematically characterized by means of electrical transport magnetization and specific heat measurements.
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S0022369719324904
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In this study we developed an instrumental hybrid catalytic system comprising cellulose fiber and volcanic pumice powder which was applied as a suitable organicinorganic hybrid catalyst for the synthesis of 2 4 5 triarylimidazole derivatives . High reaction yields were obtained in short reaction times using this catalytic system . In physical terms the high porosity of pumice provides an extremely high active surface area for electronic interactions among the components . Moreover the most distinctive properties of this catalytic system are high biodegradability simple separation of the catalyst and good reusability . The natural pumice can be recovered easily using an external magnet and reused with no significant decline in the catalytic activity . The structural characteristics of this efficient catalytic system were assessed using various analytical methods .
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Efficient natural product derived catalytic system presented. Cellulose pumice composite suitable for use as a catalyst in organic synthesis. Natural magnetic powder immobilized on cellulose fibers. High reaction yields obtained for triarylimidazole derivatives.
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S0022369719325259
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Erbium doped ZnO thin films were deposited on glass substrates by nebulizer spray pyrolysis with different doping concentrations . The deposited films are polycrystalline with a hexagonal structure with a predominant plane . The Er doped ZnO films have greater surface roughness than the undoped ZnO film . The optical transmittance of the undoped ZnO film is about 80 in the visible range . The optical bandgap of the undoped ZnO thin film is 3.29eV which is very close to the bulk ZnO . From photoluminescence spectra sharp UV emission is observed at 385nm for all the prepared films . The response of the films to ammonia NH
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Erbium doped ZnO thin films were prepared for the first time by cost effective nebulizer spray pyrolysis. Raman and photoluminescence studies confirmed the presence of oxygen vacancies for gas sensing. Er doped ZnO films exhibited high sensitivity with short response and recovery time. A possible mechanism for the adsorption of NH. molecules on the Er doped ZnO surface at room temperature is provided.
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S0022369719325351
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We report the use of a template and functional monomers in the synthesis of three novel polysulfonamide gels with new architectures and functional groups . These mesoporous polysulfonamide gels were prepared by the condensation polymerization of benzene 1 3 disulfonyl chloride linear monomers and cross linkers in the presence of a silica template by a combination of sol gel chemistry and the nanocasting technique . In this synthesis pathway in situ polymerization onto the template surface led to the construction of a silica polymer nanocomposite . Next after removal of the template the nanocomposite gels were transformed into mesoporous polysulfonamide nanospheres . After the physicochemical identification of the synthesized materials functionalized polysulfonamides were used as reusable novel catalysts with high efficiency for the Strecker reaction under mild conditions . These polymers have Brnsted Lewis acid active sites a mesoporous structure and hydrogen bonding . Moreover since these polymers are hydrogels that can absorb water they can promote the Strecker reaction through chemical absorption of the generated water as a driving force . Overall this article describes a novel synthesis procedure and application of porous polysulfonamide gels .
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Three novel nanostructured porous polysulfonamides was synthesized and used as an efficient catalyst in the Strecker reaction. The mesoporous polysulfonamidegels were prepared by combining the sol gel chemistry and nanocasting technique.
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S0022369719325363
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Zinc selenide thin films were deposited on non conducting glass substrates at 80C for 2.0h in an alkaline medium using photo assisted chemical bath deposition . The films were annealed in air at 300C for different time intervals ranging from 0 to 4.0h . The annealing time had a significant effect on the structure morphology and optical properties of the deposited films . The glancing incidence X ray diffraction analysis confirmed polycrystalline films with a hexagonal wurtzite structure . The estimated crystallite size decreased with increasing annealing time . The as deposited sample showed secondary peaks in the GIXRD and Raman spectroscopy due to unreacted selenium which disappeared after annealing . Changes in surface morphology with increasing annealing time were observed using scanning electron microscopy . The energy dispersive X ray spectrometer results showed an increase in zinc with a decrease in selenium for longer annealing times . The atomic force microscopy showed that the estimated films surface roughness decreased during annealing . Blue shifts in the absorption spectra and an increase in the energy bandgaps were observed with an increase in annealing time together with an increase in optical transmittance . Photoluminescence spectroscopy revealed blue green and red emission peaks which were all attributed to the intrinsic defects within the ZnSe . The estimated decay lifetime showed that the average decay lifetime of the films increased with annealing time . Annealing for 3.0h was found to be the optimum based on the response of the investigated properties .
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ZnSe thin films were deposited by photo assisted chemical bath method on glass slides. The deposition was done at 80C for 2h and annealed at 300C from 0.5 to 4h. The XRD shows wurtzite structure. The crystallite sizes decreased with increased annealing time. The SEM shows nanoplates and the presence of Zn and Se were confirmed by EDS. Photoluminescence spectroscopy revealed blue green and red emission peaks.
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S0022369719325417
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A facile and efficient co precipitation method has been used to synthesize pure nickel oxide nanoparticles . The synthesis of NiO has been conducted at two different pH values and in alkaline media of LiOH and NaOH and the variations in structural electrochemical and optical properties have been analyzed . The particle sizes of all of the synthesized samples were in the range 8.00020.00nm and their energy band gaps were in the range 3.5004.000eV . WilliamsonHall plots indicate that strain was introduced in the samples during the synthesis process . NiO nanoparticles synthesized in the LiOH medium at pH 12.33 showed the smallest crystallite size of 8.830nm with a lower strain value of 9.620E 6 . The charge transport and charge transfer properties of the NiO samples have been investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy measurements . CV study revealed that the redox process is diffusion controlled with a diffusion constant of the order of 10
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Crystallite size of the synthesized NiO nanoparticles decreases with increase in pH values during the synthesis process. NiO nanoparticles synthesized in LiOH medium pH 12.33 shows smallest crystallite size 8.83nm lower strain value 9.62E 6. Bandgap of the synthesized NiO nanoparticles decreases with increase in crystallite size. With increase in pH charge transfer resistance decreases results in high conductivity material for electrochromic devices. CV study reveals that the redox process is diffusion controlled with diffusion constant is of the order of 10. cm
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S002236971932551X
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A new design for expanding the absorption band of absorber in near infrared range is theoretically proposed . This design is achieved by a layered cascade metamaterial structure that consists of four metamaterial slabs . A single metamaterial slab is made of a periodic array of tilted metal layers . The results show that the layered cascade structures obviously broaden the widths of the absorption bands . The transfer matrix is derived according to the special properties of the structure designed in the paper and the absorption of the design is numerically simulated using the transfer matrix method . The influence of structural parameters on the absorption properties of metamaterial layer is analyzed the locations of the absorption peaks are red shifted with the increase of the inclination angles of the metal layers and the distance between the metal layers . The positions of the absorption peaks are blue shifted with the increase of the thicknesses of the metal layers . The widths of the absorption bands increase while the centers of absorption peaks remain the same with the increase of the thicknesses of the metamaterial slabs . According to the above results the metamaterial slabs which contain similar structural parameters are selected to constitute a layered cascade structure . The absorption of the layered cascade structures is numerically simulated and theoretically analyzed . The simulation results show that the absorption bands are obviously widened and the multi band absorption peaks are found in the near infrared region with the superposition of different suitable materials .
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A new design for broadening the absorption band of an absorber in the near infrared range is theoretically proposed. This design is achieved by a layered cascade metamaterial structure that consists of four metamaterial slabs. A single metamaterial slab is made of a periodic array of tilted metal layers. The results show that the layered cascade structures obviously broaden the absorption bands.
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S002236971932565X
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According to the mass law low frequency sound attenuation is very difficult in engineering because the mass and space of structures are usually limited . In this paper we propose a plate type acoustic metamaterial with good sound insulation in low frequency ranges . By attaching multilayered rubber and metal cylinders on a thin plate multiple flexural wave band gaps at low frequency ranges are obtained . The band structures and eigenmodes are elucidated by finite element calculations . Both the flexural wave transmission spectra and the sound transmission loss are investigated . The results show that the obtained multiple band gaps lead to more than one sound insulation peak at low frequencies . The geometrical parameter effects on the band gap frequencies are discussed . By combining cells with different geometrical parameters the formed supercell can improve the low frequency sound insulation efficiency and introduce much more variety . The results in this paper will be useful for sound and vibration control in engineering applications .
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Plate type acoustic metamaterial with multiple resonators are investigated. Multiple flexural band gaps appear at low frequency. The multiple band gaps lead to large sound insulation peaks. Sound transmission loss can be improved by designing the cell geometrical parameters.
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S0022369719325909
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Ceramic pigments due to their properties of thermal stability and suitable optical characteristics are widely used in industries . Hence the theoretical study of pigments based on density functional theory is valuable to predict the structural electronic optical and especially colorimetric properties of them . We have synthesized the malayaite CaSnSiO
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Synthesis of the malayaite and Cr doped malayaite by the conventional ceramic route. DFT TDDFT calculations of the structures by the Quantum ESPRESSO and YAMBO code. Shift of the XRD and Raman peaks and resonance enhancement of vibrational modes for doped samples. Decrease of the gap and Fermi energies with increasing the doping concentration. Checking the correspondence of the absorption spectra and colorimetric results for all samples.
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S0022369719325958
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Experimental evidences have revealed the existence of intrinsic defects in Half Heusler AuMnSn . In this work using density functional theory we explore the energetics electronic and magnetic properties of intrinsic point defects in HH AMS crystal compound . The defects considered are antisite interstice vacancy and atom swap defects . We find relatively low negative formation energy for Au
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Non stoichiometric composition in many synthesized half Heusler AuMnSn is explained. Au interstitial defect in AuMnSn has negative formation energy FE . Au. Mn and Sn. Mn antisite have negative FE. Sn. Au antisite and Sn interstitial point defects have low FE. HMF exists in AuMnSn with Sn. Au antisite and Sn interstitial point defects
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S0022369719326083
|
Peeling is considered to be the main technical obstacle for coating applications . There are many factors that affect the peeling process of coatings . The interfacial properties of the coating and substrate play a crucial role in the peeling process . In this study the work of adhesion W
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Diamond 001 Si 001 and Si 001 Ti 0001 interfaces have been investigated. Typical polar covalent bonds occur in the diamond 001 Si 001 interface. The Si 001 Ti 0001 interface is formed of weak covalent and metallic bonds. The deformation of Ti is the key failure mode of interface in the shear process.
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S0022369719326277
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Choosing a suitable two dimensional nanomaterial as a carrier for noble metals is crucial for improving the catalytic performance and reducing the cost of nanocatalysts . In this study we used ultrathin porous g C
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Ultrathin porous g C. nanosheets fabricated as a favorable carrier. Au nanoparticles loaded on various carriers for catalytic reduction of nitrophenol. Au g C. nanocomposite catalyst had outstanding catalytic properties.
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S0022369719326642
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Reduced graphene oxide gallium nitride nanocomposites were synthesized by a facile single step chemical reduction process with variation in the concentration of GaN from GaN1 @ RGOGaN to GaN20 @ RGOGaN . Scanning electron microscopy and X ray diffraction results revealed that the particle sizes of the GaN nanoparticles and the crystallite sizes of RGOGaN nanocomposites were in the ranges of178379 and 0.2430.245nm respectively . The Gaussian deconvolution of Ga N and Ga for GaN1 @ RGOGaN and GaN7 @ RGOGaN indicated various binding energies of core orbital electronic configuration for the GaN in the RGOGaN nanocomposite networks . The X ray photoelectron spectroscopy measurements showed the calculated atomic percentage of Ga and N for GaN1 @ RGOGaN and GaN7 @ RGOGaN ranged within 2.325.98 and 4.917.33 respectively . The maximum specific capacitance was forGaN5 @ RGOGaNwith454F g at 10mV s scan rate as measured using cyclic voltammetry . Similar results were found using the galvanostatic chargedischarge method resulting in specific capacitance of 116.8146.1F g at a current density of 1A g. Moreover very low charge transfer resistance was developed reaching a maximum of only 2.36 for electrochemical impedance spectroscopy analysis . These electrochemical measurement results indicated good capacitive behavior of the RGOGaN nanocomposites .
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RGOGaN nanocomposites were synthesized by a facile single step chemical reduction process. Particle and crystallite sizes of nanocomposites were 178379 and 0.2430.245 nm respectively. High specific capacitance of 454 F g at a scan rate of 10 mV s with cyclic stability up to 75 over 950 cycles in 1M H. SO. The study showed good performance of the hybrid material for supercapacitor devices.
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S002236971932668X
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Magnetic nanoparticles have been synthesized on mesoporous silica by a simple method without the need for either an alkali or an organic solvent nor for rigorous pH control making it a safe procedure for the nanomedicine field . The systems have been exhaustively characterized through different instrumental techniques including the analysis of physicochemical properties by N
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A straightforward and biocompatible method for the production of Fe. on mesoporous silica has been developed. Structural and physicochemical properties of the samples have been determined. TEM and HAADF STEM images revealed the presence of different sized Fe particles. SAED and XRD patterns confirmed the presence of Fe. nanoparticles on SBA 15. Magnetic properties have been determined by means of a SQUID magnetometer.
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S0022369719326769
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First time reports the rapid polymerization of hydrazine oxalyl chloride based polyamide at room temperature . The polyamide has been synthesized by condensation polymerization using hydrazine and oxalyl chloride at 25C using n haxane as solvent . During condensation polymerization HCl has been eliminated which led to HCl doped polymer . Post polymerization modifications have also been done by doping with BF
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In situ HCl doped based hydrazine and oxalyl chloride polyamide HOP was synthesized. Rapid polymerization performed within 10min. Inter chain H. exchange in solid state of polyamide was analyzed. HOP shows conductivity in range of 10. S cm. Capacitance of HOP is recorded in F range.
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S0022369719326782
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Crystal structure prediction and characterization data have been computed for two novel carbon free energetic compounds namely 1 4 2 3 5 6 dioxatetrazinane and its 2 5 dinitro derivative . Dynamic and mechanical stability of these crystalline materials at ambient pressure has been confirmed . Ab initio molecular dynamics simulations confirmed thermal stability of DOTZ at 298K and of DNDOTZ at 77K . A comprehensive spectral characterization has been performed to provide information for future experimental identification . The parent molecule exhibits powerful detonation properties which exceed those of most compounds hitherto obtained experimentally or predicted theoretically . Meanwhile DNDOTZ is predicted to be an effective solid oxidant for common explosives with negative oxygen balance such as TNT TNB DATB and TATB . Such mixtures demonstrate better propulsive properties than corresponding mixtures of these explosives with gaseous oxygen . By virtue of its zero oxygen balance the only detonation products of DOTZ are environmentally friendly molecular nitrogen and water . Therefore this compound is of great potential interest for further energetic applications .
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Two novel carbon free crystalline energetic compounds are predicted and characterized. One of them represents a powerful green explosive yielding only N. and H. O as detonation products. Its detonation properties exceed those of most explosives hitherto synthesized or predicted. The other compound is a very effective solid oxidant which outperforms gaseous oxygen.
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S002236971932685X
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First principles method based on density functional theory is applied to calculate the Mg TiN interfacial properties including adhesion work electronic structure and interface energy . The Mg slab with five atomic layers and TiN slab with thirteen layers were used to construct the interfaces after the surface convergence test . And three Mg TiN interfaces with different stacking sequences for both the Ti and N terminated interfaces were studied . The N terminated TL interface is the most stable as it has the largest
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Six Mg 0001 TiN 111 models were studied by using first principles method. The N terminated TL site stacking interface is the most stable interface. The interfacial bonding character of N terminated TL stacking is mainly covalent and ionic. TiN particles can act as an effective heterogeneous nucleation substrate of Mg
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S0022369719326903
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With a growing interest in optically active sites in diamond and related materials the need exists to identify novel defects that operate at desired wavelengths . In this study we employ time dependent density functional theory to search a large compositional space for novel color centers in diamond . Results are benchmarked against bulk computational approaches as well as experimental literature and correspondence is observed between molecular and bulk values . Novel defects with potential for infrared emission are identified .
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TD DFT allows rapid computational identification of novel color centers. Novel color centers with potential for infrared emission are identified. Novel color centers with potential application to quantum technologies.
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S0022369719327118
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The main aim of this study is to fabricate the magnetic polymeric nanocomposite supported on the mesoporous boehmite by the facile preparation method . The core shell magnetic boehmite was synthesized by the co precipitation method . The coverage of polymeric layers was applied to modify the surface of magnetic boehmite for the adsorption of methylene blue and mercury ions in the single and binary solutions . The prepared samples were characterized by employing general tests including XRD FTIR FESEM TEM XPS BET and VSM . TEM and FESEM images displayed the well dispersed nanoparticles in the structure of nanocomposites with size of less than 40nm . The isotherm adsorption of the adsorbent was evaluated by using Langmuir Freundlich and the extended Langmuir in the single and multicomponent aqueous solutions . The experimental data was in the good agreement with Langmuir equation in the both unary and co adsorption process . The capacity of the magnetic polymeric nanocomposite was measured to be 70.03 and 36.94mg g for the adsorption of methylene blue and mercury ions respectively . The amount of adsorbed mercury and methylene blue ions in the competitive adsorption was calculated to be 14.93 and 10.17mg g respectively . The kinetic study was also conducted by two various models including pseudo first and second order models . The results indicated that the pseudo second order can justify the adsorption in the single and binary solutions . Reusability of the prepared sample in the competitive adsorption for six cycles indicated the appropriate performance of the used adsorbent for the industrial applications .
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Novel magnetic polymeric nanocomposite was prepared by a facile preparation method. Magnetic polymeric nanocomposite was included boehmite magnetite SiO. and polylactic acid. Competitive adsorption of methylene blue and mercury ions was studied in the binary solution. Maximum adsorption capacity was measured to be 14.93mg g for mercury ions in the presence of methylene blue. Magnetic polymeric adsorbent was evaluated by XRD XPS BET TEM and VSM techniques.
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S0022369719327179
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This study assessed the ability of glass ceramics that included zirconolite and barite to protect against different kinds of radiation . Firstly the mass attenuation coefficient values of five different glass ceramics with different amounts of SO
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values of glass ceramics were simulated by MCNPX codes. Vital shielding parameters of glass ceramics HVL LAC Z. Z. and EBF were surveyed. R was used to determine the ability of the ceramics to attenuate fast neutrons. The ability of the glass ceramics to stop alpha and proton particles was determined.
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S0022369719327271
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In this study europium and dysprosium doped phosphors i.e . ZnO Eu ZnO Dy and Eu Dy co doped zinc oxide semiconductor phosphors with optimized concentrations were synthesized using the conventional solid state reaction method in an oxygen environment . Detailed structural morphological and compositional investigations were conducted using X ray diffraction scanning electron microscopy and energy dispersive X ray measurements respectively . Photoluminescence emission spectra were recorded under different excitation wavelengths to assess the optical characteristics . Electrical analysis was conducted using an inductance capacitance and resistance meter and a Keithley source meter and magnetic analysis was performed using a vibrating sample magnetometer . XRD confirmed the presence of Eu and Dy ions because the diffraction peaks matched perfectly with those for Eu
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ZnO Eu Dy shows luminescence. ZnO Eu Dy is magnetic conductive. ZnO Eu Dy is luminomagnetic.
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S0022369719327386
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For two dimensional materials a pure large out of plane piezoelectric response compatible with the nowadays bottom top gate technologies is highly desired . In this work the piezoelectric properties of penta graphene monolayer are studied with pure out of plane piezoelectric effect by density functional theory . However the
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Pure out of plane piezoelectric effect is found in penta graphene. A Janus penta monolayer is constructed to improve piezoelectric properties of penta graphene. Proposed penta monolayer with high and pure out of plane piezoelectric effect.
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S0022369719327635
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We investigate defect induced electronic and magnetic properties of zinc oxide nanocrystalline powders prepared by mechanical milling . The average crystallite size decreases as the milling time is increased but the wurtzite structure is stable even after 60 hours of milling . The structural properties are characterized by X ray diffraction and transmission electron microscopy . The chemical composition of pure unmilled and as milled powders is determined by X ray photoelectron spectroscopy . Raman scattering spectra were analyzed to find evidence of crystallinity and defect structures in the milled powders . The results obtained from electronic paramagnetic resonance studies demonstrate that the defects are due to both oxygen and zinc vacancies . Since defect induced magnetism has potential application in spintronic devices we measured the
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Defects induced electronic and magnetic properties of ZnO nanocrystals. Inexpensive ball milling process to prepare the nanoscale ZnO powders with high purity. Vacancies are largely responsible for ferro magnetic properties of ZnO nanocrystals and which favors the superior application in devices as compared to bulk.
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S0022369719327647
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Based on the theories of solid state physics and quantum fracture mechanics a theoretical model is proposed to investigate the fracture properties of pre cracked single layer graphene and the analytical expressions of failure strength and fracture toughness of pre cracked graphene are derived . Simultaneously the failure strength of pre cracked graphene is calculated by finite element method based on molecular structure mechanics . The results of FEM are in good agreement with the theoretical counterparts . Via the theoretical analyses and numerical calculations the effects of crack length crack tip radius and domain size of graphene on the failure strength and fracture toughness of pre cracked graphene are systematically studied . It is found that the failure strength of pre cracked graphene gradually decreases with increasing crack length and domain size of graphene . However as the crack tip radius increases the failure strength gradually increases . In addition it is also found that the crack length and domain size of graphene have little impact on the fracture toughness of graphene . The fracture toughness is significantly affected by crack tip radius .
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The theoretical model of fracture properties of pre cracked graphene is proposed. The analytical expressions of failure strength and fracture toughness are derived. The results of theoretical model are compared with those of FEM. The failure strength and fracture toughness are affected by several factors. These factors include crack length crack tip radius and domain size of graphene.
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S0022369719327672
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Silver nitrate of desired concentration was doped in the as synthesized MCM 41 mesoporous silica and the prepared samples are spin coated onto interdigitated thin films with silver on glass slide . The interdigitated thin film electrodes made of silver were fabricated by RF magnetron sputtering with power of 60Wat 7.210
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Five order of magnitude change in impedance from undoped to Ag doped MCM 41 sample. In house sensor system of silver interdigitated electrodes and Ag doped MCM 41. Ag doped MCM41 displayed response and recovery time of 24s and 32s respectively. The hysteresis of the as synthesized sample was 1.2 with standard deviation.
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S0022369719327726
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In this research we have investigated growth path relative stability surface energy sphericity and structural analysis of Au Pt Au Rh Au Cu and Au Pd nanoalloys created during gas condensation methodology via molecular dynamics MD simulation . The Au Pt was more stable and the Au Pd was less stable than other nanoalloys . In well agreement with the experiment the gold atoms rest at the clusters surface whereas the other atoms position at the cores of the nanoclusters . It is also shown that this arrangement exists for surface energy at all simulation times E
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Formation of some Au based nanoclusters was studied in gas phase condensation. Trend of relative stability and surface energy of clusters was also investigated. The formed Au Rh and Au Pt clusters had negative values of the surface energy. Some ordered structures fcc like or hcp like atoms were found in the nanoclusters.
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S0022369719328021
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In recent years supercapacitors have attracted much attention due to their excellent chargedischarge performance long term cycle lifetimes and high specific power . Transition metal oxides are promising candidates for environmentally friendly low cost and high powered energy storage materials . In addition the use of one dimensional nanostructures can markedly enhance the characteristic properties of the transition metal oxides . In this work ZnCo
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ZnCo. C composite nanofibers were successfully fabricated using a simple electrospinning method. ZnCo. C nanofiber based supercapacitors exhibit high specific capacitance e.g. 90.0F g at a current density of 8.0 A g. ZnCo. C composite nanofibers remain superior working stability with capacitance after 1000 cycles in air.
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S0022369719328057
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In this study a composite comprising WC particulate reinforced SiAlON was fabricated by spark plasma sintering in order to develop a hard to hard phase configuration and to toughen the hard matrix through particulate reinforcement . Irrespective of the composition the sintered samples were almost theoretically dense . The nature of the overall sintering process for the composite appeared to be guided by the liquid phase sintering of the SiAlON phase . Microstructural analyses using scanning and transmission electron microscopy indicated the presence of both equiaxed and elongated SiAlON grains . The WC grains principally appeared equiaxed in nature . A reaction product was not observed at the WC SiAlON interface . High angle annular dark field scanning transmission electron microscopy imaging indicated the reasonable distribution of the elements within the constituent grains and grain boundary . The presence of an intergranular glassy phase was confirmed which was principally rich in oxygen and yttrium with some occasional tungsten in the case of triple junctions . The composite exhibited an acceptable combination of flexural strength hardness and fracture toughness with values around 489MPa 20GPa and 6MPa m
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Dense WC particulate reinforced SiAlON composite is successfully prepared. Sintering of composite is principally governed by that of SiAlON. TEM HRTEM STEM HAADF image substantiates detailing of composite microstructure. Well acceptable combination of MOR 489MPa HV. 20GPa K. 6MPa m. obtained. Composite caused higher damage to Si. counterbody compared to the monolith.
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S0022369719328197
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In this study we investigated some physical properties of AB compounds in different structural phases based on density functional theory . The effects of different hydrostatic pressures and biaxial strains on the band orders of AB compounds were investigated . The calculations were conducted with the Wien2k package in the presence of spin orbit coupling . The results showed that the topological
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Topological phases of AB A Sc Y and B Sb Bi compounds are studied. Optical properties of AB compounds are investigated. High pressures lead to topological phase transitions and band inversions. Pressure increases crystal field and bandwidth of valence and conduction bands. High pressures have unusual effects on topological phases of ScSb and YSb.
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S0022369719328252
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Porous carbon originate d from Metal Organic Frameworks has attracted the attention of scholars because it inherits large specific surface area plenty of pore structure and adjustable morphology . Here we reported N doped porous carbon with hierarchical pore structure obtained from nickel based metal organic framework . Due to its exceptional porosity N doped nature and large surface area the NPC exhibited superior electrochemical storage performance for lithium ion batteries . The resulting NPC material achieves excellent reversible capacity 725mAh g
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A flexible strategy is exploit to fabricate Nitrogen doped Porous Carbon NPC . The NPC have hierarchical pore structures which can accelerate the diffusion of Li. The NPC exhibits high specific capacity and good rate performance. The synthesis route provides a new perspective to produce NPC.
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S0022369719328264
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The present study reports on the appreciable magnetic entropy change observed in hybrid structures of cobalt hydroxide nanoparticles inside a polymer matrix . The preparation of a magnetic composite of cobalt hydroxide nanoparticles lodged in a polymer matrix of sulfonated polystyrene by the method of the ion exchange mechanism is outlined . The dimensionality introduced by the resin provides constraints to the particle growth thereby leading to the formation of a nearly homogeneous distribution of particle . The polymer template serves as a stabilizing and isolating agent . The composite nanostructure shows magnetocaloric effect near to the low temperature zone with an entropy change of 5J kgK at an applied magnetic field of 7T .
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Ion exchange mechanism assisted loading of cobalt ions in seralite strong resin cation 120. Subsequent conversion of cobalt ions to cobalt hydroxide to realize cobalt hydroxide polymer nanocomposite. Composites show a magnetic entropy change of 5J kgK at an applied magnetic field of 7Tat 7.5K.
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S0022369719328628
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Sodium alginate is a natural biomacromolecule with promising applications as a flocculant for wastewater treatment due to its biodegradability and non toxicity . To enhance the flocculating efficiency simplify the synthetic process of the flocculants and expand the application scope of alginate a novel amphoteric flocculant was synthesized through reaction of alginate with 3 chloro 2 hydroxypropyltrimethyl ammonium chloride under alkaline conditions . The structures of the flocculants were characterized using various methods . The flocculants demonstrated nanoparticle sizes with a narrow distribution . The amphoteric flocculant could not only effectively remove the positively charged Pb
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Novel amphoteric nano flocculants were prepared through modification of alginate. The flocculants had high removal rates for Pb. and humic acid. Chelation and electrostatic interaction mechanisms were involved for both pollutants. Adsorption kinetics accorded with a quasi second order model. The new amphoteric flocculant is a promising agent for wastewater treatment.
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S0022369719328963
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Photo electrochemical cells have been widely studied as an eco friendly method of producing hydrogen fuel . Among the various materials hematite Fe
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We controlled the length of vertically aligned hematite NRs by adjusting the chemical concentrations. The PEC performance of vertically aligned hematite NRs was strongly dependent on the length of the NRs. For the 800C high temperature annealing the optimal length of NRs yielding the best PEC performance was 300500nm. The cobalt phosphate modified hematite NRs showed 1.54mAcm 2 of photocurrent at 1.23V vs. RHE.
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S0022369720300044
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A polymer ZnO colloidal solution was prepared as the organic inorganic composite electron transport layer of inverted polymer solar cells by successive modification of ZnO particles with organic dispersant and polyethyleneimine which offers an alternative to previously used complicated processes such as high temperature annealing or multi layer coatings . The modification of ZnO surfaces with 2 acetic acid provides colloidal stability and prevents aggregation of ZnO particles after adding PEI into the ZnO colloidal solution . The amount of incorporated PEI was increased to 10wt and the cell performance parameters of
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Stable PEI ZnO composite colloidal solution was prepared for electron transport layer in polymer solar cell. Successive surface modification of ZnO with MEA and PEI yielded stable composite colloid. The 40 of enhancement in PCE was obtained by using composite colloid.
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S0022369720300408
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In this work we have performed first principles calculations to investigate effects of pressure on structural and mechanical properties as well as temperature on thermodynamic properties of refractory ZrTM . ZrTM are mechanically stable and ductile at 018GPa and elastic constants and elastic moduli can be improved at appropriate pressures . The lattice parameters phonon dispersions phonon densities of states heat capacity thermal expansion coefficient Debye temperature and Grneisen constant at temperatures of 01500K and pressures of 018GPa were investigated . The phonon dispersions showed that ZrTM are dynamically stable . The thermal expansion coefficients of ZrTM are in a sequence of ZrFe ZrRu ZrOs . The dependence of temperature and pressure on Grneisen parameter is opposite to Debye temperature .
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The mechanical and thermodynamic properties of ZrTM TM Fe Ru Os are studied. The mechanical properties of ZrTM TM Fe Ru Os can be improved by pressure. ZrTM can form a covalent bond between Zr and TM atoms along the 111 direction. of ZrTM is close to the Dulong and Petit limits about 50 J mol. .k. . At 0 GPa and 300 K the values for ZrFe ZrAu and ZrOs are 30.4210. 28.9910. and 21.9810. respectively.
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S0022369720300809
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Electronic structure optical and thermoelectric properties of the HfSSe Janus monolayer have been comprehensively investigated using first principles calculations based on the full potential linearized augmented plane wave method . Results show that the HfSSe Janus monolayer is dynamically stable . Electronic properties features indicate that the two dimensional material at hand is an indirect gap semiconductor with a band gap of 0.756eV calculated by the Wu Cohen scheme within generalized gradient approximation . The spin orbit coupling inclusion in the calculations breaks the degeneracy in both valence and conduction bands and gives a smaller band gap of 0.653eV . Additionally the external strain effect on the electronic structure is also examined . The metallization can be achieved when a compressive strain of 8 is applied . Optical properties results suggest that the studied 2D monolayer may be a promising candidate to be applied in nano optoelectronic devices provided that it displays a wide absorption band from visible to ultraviolet with high absorption coefficient of the order of 10
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HfSSe monolayer is dynamically stable. HfSSe is an indirect gap semiconductor with a band gap of 0.756eV. Spin orbit coupling removes the energy degeneracy and decreases slightly the band gap. HfSSe shows good optical absorption from visible to ultraviolet regime. HfSSe possesses high thermopower and power factor and the hole doping is favorable.
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S0022369720300846
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Calculations based on collinear and non collinear spin density functional theory were used to investigate the complex dielectric function spectrum energy band gap electronic band structure and the effective mass of the charge carriers of the R3c BiFeO
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R3c BiFeO3 magnetoelectric compound was studied using non collinear spin DFT U. Effects of the collinear and non collinear spin DFT U were analyzed. Complex dielectric function spectrum agrees with experimental results. R3c BiFeO3 compound presents an indirect energy gap of 2.2eV. Hole and electron effective mass eigenvalues of the R3c BiFeO3 were computed.
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S0022369720301001
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Functional nanosized two dimensional clay mineral particles are considered as ideal host materials to manipulate the properties of incorporated organic molecules due to their high cation exchange capacity layer structure and intercalation properties . The interlayer height of clay layers can be manipulated by simultaneous wetting and drying steps . Here we have studied the chromatic behaviour of an organic dye generated
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Synthesis of tetraindolyl derivative. Preparation of clay mineral tetraindolyl hybrid self standing film. Colour switching of hybrid film due to the change in gallery height of clay. Colour switching was reversible with a very good stability. Such colour switching is suitable for colorimetric sensor optical switching optical memory etc.
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S0022369720301189
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Two dimensional materials have attracted increasing research interest due to their unique physical and chemical properties . As a typical 2D material ZnO monolayers not only generate scientific interest but also may have important technological applications . However it is still a great challenge for ZnO monolayers to be used in electron emission devices . Here the first principles calculations based on DFT D2 have been used to investigate the structural stabilities electronic structure electron emission properties and diffusion behaviors of
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The top of the center of the hexagonal ring of ZnO is the most stable adsorption site. The interaction between the. adatoms and ZnO monolayers results in ionic bonding. The band gaps of. ZnO monolayers are reduced to zero and exhibit metallic characteristics. After the alkali metal is adsorbed a rapidly reduced work function 2.743.26eV was obtained.
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S0022369720301220
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To improve hydrogen storage property of Mg based alloy the MgCeYNi 10wt M composites were prepared by the combination of alloying and ball milling and their microstructure phase evolution as well as hydrogen storage thermodynamic and kinetic properties were investigated by XRD PCT and DSC methods . The result shows that the hydrogenated samples are composed of MgH
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MgCeYNi TM composites are prepared by the combination of alloying and ball milling. The Zr and V elements are efficient to disorganize the thermodynamic Mg based alloy. The positive role of reversible reaction between the VH. and VH. is confirmed. Activation energy is determined by the both of element property and reaction path.
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S0022369720301244
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Magnetic graphene oxide has rapid adsorption kinetics and a high capacity for adsorbing aqueous Co and it was prepared in this study by controlling the synthesis conditions . The adsorption mechanism was analyzed based on the adsorption isotherms thermodynamics kinetics and post adsorption characteristics to understand the adsorption interactions . At 20C the adsorption equilibrium was reached in 5min with an adsorption quantity of 379.2mgL
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Method for preparing magnetic graphene oxide MGO to adsorb aqueous Co II . MGO dosage of 500 mg L. adsorbed 94.5 of Co II at 200.62 mg L. MGO readily recovered by magnetic separation for regeneration and reuse. Adsorption kinetics and capacity higher for MGO compared with other adsorbents. Adsorption mechanism clarified based on adsorption interactions.
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S0022369720302201
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In the result of increasing energy demand rechargeable Li ion batteries with high energy density are suitable sustainable power sources for the energy storage generations . Keggin type polyoxometalates are being regarded as an electrode material for energy storage devices though advanced improvement is adaptable for futuristic applications . Consequently we demonstrate PMo
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Keggin type POM synthesis is simple required temperature below 200C. Li. HPMo. clusters is not used anywhere in battery applications. The 22 electron insertion in the POM ease stable cycling at higher current rates. POM with lithium as counter cation exhibits better capacity and energy density. It can lay the groundwork for future electrodes in various applications as well.
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S0022369720302341
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Cyclopentadithiophene and benzothiadiazole derivatives have promising characteristics for use in organic solar cells . In this study we theoretically investigated two donoracceptor copolymers comprising 2 thiadiazol 4 yl 4H cyclopentadithiophen 4 one and 2 thiadiazol 4 yl 4H cyclopentadithiophen 4 ylidene malononitrile with alternating donoracceptor building units . Different copolymer chain lengths were extended to investigate their structural electronic and photo physical properties based on density functional theory calculations . The copolymers exhibited high planarity reduced band gap energies and broad absorption in the visible range and thus they may enhance the performance of organic solar cells . The transition density matrix plots were simulated for the copolymers and used to evaluate holeelectron localization interactions donoracceptor interactions and the electronic excitation processes in their excited states . The charge transfer properties fill factors and open circuit voltages were estimated . Based on our simulations we found that the trimer was the most suitable conformation among the copolymers for designing high performance bulk heterojunction solar cells . The power conversion efficiency of the BHJ based blended copolymers PCBM was estimated as 9.5 . Thus the appropriate design of conjugated materials could considerably enhance the donor properties to further improve the performance of BHJ solar cells .
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Design of donoracceptor block copolymers for use in bulk heterojunction solar cells. Rigid planar low band gap copolymers derived from cyclopentadithiophene. Chain length significantly affected the optoelectronic properties. Transition density matrix plots simulated to evaluate electronic excitation. Trimer type copolymers promising candidates for photovoltaic applications.
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S0022369720302729
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Solidification experiment of Mg 4Y 3Nd 1.2Al alloy cast in a step like sand mold casting shows that a slow cooling rather than a fast cooling leads to grain refinement during solidification with in situ formed nucleant particles Al
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The grain refinement of Mg 4Y 3Nd 1.2Al alloy is achieved at a slow cooling rate with in situ formed nucleant particles in melt. The refinement of mesh size from 3 m to 1 m does not apparently influence the predicted results. A critical particle size exists above which the grain refinement becomes less sensitive to cooling rate. Surviving possibility of particle in interdendritic area is simulated to be higher under a slow cooling condition.
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S0022369720302730
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Photocatalytic splitting water is a new clean green technology that has become a research hotspot in the scientific community . Among them cadmium sulfide is a classic photocatalyst . But applications are limited due to photo corrosion and fast electron hole recombination . Herein hollow CdS tubes with special morphology were successfully modified by simple vapor deposition of graphitic carbon nitride . The obtained 1D binary heterojunction photocatalyst showed good photohydrolysis hydrogen production performance under visible light . The introduction of CN prevented photo corrosion of CdS so it also had great cycle performance . At the same time the proper amount of CN deposition was studied . The most suitable sample showed the best hydrogen release rate 392.84molg
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The 1D CdS hollow tube structure with special morphology was modified by simple vapor deposition of CN. The CN outside of CdS hollow tube prevented photo corrosion of CdS and also formed a binary heterojunction. The modified CdS hollow tube exhibited higher photocatalytic performances and photochemical stability.
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S002236972030305X
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Hybrid organicinorganic lead halide perovskite is still hampered by the toxicity of Pb as well as its structural stability in the open air . Herein based on the density functional theory computation we show that tin based layered quasi two dimensional Ruddlesden Popper hybrid organic inorganic perovskite X
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By adjusting the number of layers the band gap of the material is regulated. The significant effect of different passivation ligands on carrier mobility. Few layered RuddlesdenPopper hybrid M2 MA n 1SnnI3n 1 perovskite would suitable for solar cell application.
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S0022369720303139
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The spinel oxides have received remarkable attention in recent years for being promising materials for optoelectronic and thermoelectric applications . In this paper the thermodynamic stability of the XIn
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Exploring the potential of XIn. X Mg Zn Cd spinel oxides for renewable energy applications. High thermodynamic stability. Highly absorbent materials. Large thermoelectric figure of merit. Potential resources for clean and sustainable energy.
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S0022369720303723
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This paper presents a simple expression for tunneling diameter between neighboring carbon nanotubes in polymer CNT nanocomposites . Two developed models for conductivity of PCNT assuming interphase tunneling effect the fraction of networks and the whole resistance of components are linked to suggest the tunneling diameter by CNT interphase and tunneling properties . The suggested equation expresses the variation of tunneling diameter at different filler concentrations for some samples . In addition the suggested equation is applied to predict and justify the tunneling diameter at various levels of all factors . The tunneling diameter increases by the addition of filler concentration in the samples . In addition thick CNT poor percolation onset dense interphase high net fraction high CNT conductivity and short tunneling distance expand the tunneling diameter . This study can help the researchers to enlarge the tunneling diameter providing the most desirable conductivity in nanocomposites .
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We express the tunneling diameter between near CNT in polymer nanocomposites. The tunneling diameter is formulated by CNT interphase and tunneling properties. The tunneling diameter increases by the addition of filler concentration. Dense interphase high net fraction and short tunnels expand the tunneling diameter. This study helps to enlarge the tunneling diameter improving the conductivity.
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S0022369720303772
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The usage of ethylene glycol as high boiling solvent results in the formation of ultrafine highly crystalline tin doped magnetite nanoparticles with an average size equal to 4.85nm . The oxidation of Sn
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The glycol assisted co precipitation was used as the synthesis method of tin doped magnetite. The XPS and Mssbauer spectra confirm the existence of only Sn. ions in magnetite structure. Ultrafine Fe. Sn. NPs have high saturation magnetization equal to 49.7 emu g. The very low coercivity equaled 13.29Oe was correlated with superparamagnetic behavior.
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S0022369720303838
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Integrating oxide materials onto semiconductors is a critical part of the design of new electronic and photonic oxide devices . Sodium niobate NaNbO
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NaNbO. 4H SiC heterostructures were fabricated by a sol gel method. Conduction mechanism was realized in NaNbO. 4H SiC heterostructure. The density of trap states and the corresponding activation energy were determined. The homogeneous resistance switching behavior was observed in Pt NaNbO. 4H SiC device.
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S0022369720304030
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Presently the relaxation is mainly an empirical field of science . Despite the availability of microscopic theoretical models in practice the relaxation phenomena are generally described by a few empirical relaxation functions .
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The general patterns of the relaxation phenomena are identified. A new classification of the relaxation processes is suggested. A generalized equation describing the known types of relaxation is proposed. A number of new relaxation functions are obtained.
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S0022369720304376
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Mesoporous NiS has been synthesized by a hydrothermal route using thiourea as a sulfur source . FESEM and TEM images confirm the formation of one dimension or three dimension nanostructures . 1 D or 3 D nanostructures were formed by varying the concentration of thiourea . The growth mechanisms for formation of 1 D and 3 D nano structures have been studied in detail . No other phases of nickel sulfide were detected in the XRD and XPS spectra . Comparative studies of the electrochemical behaviour of the synthesized NiS have been performed in various alkaline electrolytes . NiS showed superior electrochemical performance in aqueous LiOH electrolyte than aqueous KOH and NaOH electrolye.1 D growth of NiS nano rods showed to a maximum areal capacitance of 3.66F cm
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1 D and 3 D nanostructures successfully synthesized by a hydrothermal route. Growth mechanism of 1 D and 3 D nanostructures discuss in detail. Electrochemical studies of the synthesized NiS have been performed in various alkaline electrolytes KOH LiOH and NaOH .
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S0022369720304418
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This study aimed to develop a highly efficient Ru catalyst using mixed oxide support of lanthanides and MgO . Mixed oxide support of Er
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Mix oxide MgOEr. supported Ru catalysts were applied to ammonia synthesis. Mix oxide MgOEr. supports were prepared by co precipitation method. Ru MgOEr. catalysts showed efficient ammonia synthesis activity. Catalytic activity was highly dependent on the textural properties of Ru MgOEr
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S002236972030456X
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The electronic and transport properties of sawtooth penta graphene nanoribbons are investigated using density functional theory and semi empirical extended Hckel method in combination with nonequilibrium Green functions . The configurations are theoretically studied in terms of bare edges and edges terminated by non metallic atoms such as identical edge termination and alternate edge termination . It is found that SSPGNR band gap can be controlled through changing various passivation elements as well as termination forms which leads to the transition from a semiconductor to a metal or a semimetal . For the influence on transport properties P and Si atoms of alternate cases improve significantly the weak point of the bare and traditionally passivated models . The 9 order rise of current magnitude is observed in PH SSPGNR and SiH SSPGNR compared to HH SSPGNR and PP SSPGNR . Interestingly oscillation current voltage characteristic appears when SSPGNR is identically functionalized by Si atoms . These outcomes derive from the strong dependence of SSPGNRs on edge chemistry influence suggesting that kinds of passivation atoms and termination types could be used to manipulate properties of novel and promising materials in nano electronic devices .
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The electronic structures and transport properties of the sawtooth penta graphene nanoribbons SSPGNRs are very sensitive to termination elements H P Si . Alternate edge functionalization by P or Si together with H atoms not only enriches SSPGNR current by 10times but also brings high feasibility to form functionalized ribbons which indicates good low dimensional structures likely to exist in experiments. Oscillation current voltage characteristic appears when SSPGNR is functionalized identically by Si atoms. This has the potential to be used in special electronic devices.
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S0022369720305291
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We obtain resistance characteristics for molybdenum disulfide and temperature dependent coefficient of friction 0.0005 which could be a superlubricating state for molybdenum disulfide coatings or thin films . Considering molybdenum disulfide lubrication we adopt the transition state approach to calculate the temperature dependent friction behavior . We have performed intensive calibrations via verified models considering previous experimental friction tests on some thin solid film samples which measured the COF in 4.2 K 77 K and room temperature conditions to accommodate the actual working condition . To improve the performance of molybdenum disulfide we predict its better COF which could be a superlubricating state COF
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or very low coefficient of friction for solid MoS. lubricant. Our results have negative friction coefficients for superlubricity. Coefficient of friction decreases to 0.0005 once we decrease the activation volume.
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S0022369720305370
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The design of efficient non precious metal electrocatalysts is still the hot topic for water oxidation . However the reported transition metal based electrocatalysts usually exhibit far lower activity compared with precious metals . In this work we report the excellent oxygen evolution reaction performance of Mo
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Mo. shows a lower overpotential than RuO. and IrO. C. The half filling 3d orbit of FeNi favors for appropriate adsorption for OH. The improved electrical conductance by Mo. C improves OER kinetics. This work provides an efficient earth abundant electrocatalyst for water oxidation.
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S0022369720305655
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We report the synthesis of iron mononitride thin films having zinc blende type structure deposited using a direct current magnetron sputtering process on amorphous quartz substrates . The effect of substrate temperature
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Stoichiometric phase in FeN can be achieved in a narrow temperature range only. Lattice parameter of FeN at 4.28 is closest to its theoretical value at 4.24 . Minimization of stress generated during film growth led to stoichiometric FeN. Through Fe N K edge XANES ZB type structure of FeN was confirmed. First ever usage of EXAFS in FeN yield bond distances as predicted for ZB type FeN.
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