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Differential diagnosis of Crohn’s disease and intestinal tuberculosis based on ATR-FTIR spectroscopy combined with machine learning 被引量:1
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作者 Yuan-Peng Li Tian-Yu Lu +5 位作者 Fu-Rong Huang Wei-Min Zhang Zhen-Qiang Chen Pei-Wen Guang Liang-Yu Deng Xin-Hao Yang 《World Journal of Gastroenterology》 SCIE CAS 2024年第10期1377-1392,共16页
BACKGROUND Crohn’s disease(CD)is often misdiagnosed as intestinal tuberculosis(ITB).However,the treatment and prognosis of these two diseases are dramatically different.Therefore,it is important to develop a method t... BACKGROUND Crohn’s disease(CD)is often misdiagnosed as intestinal tuberculosis(ITB).However,the treatment and prognosis of these two diseases are dramatically different.Therefore,it is important to develop a method to identify CD and ITB with high accuracy,specificity,and speed.AIM To develop a method to identify CD and ITB with high accuracy,specificity,and speed.METHODS A total of 72 paraffin wax-embedded tissue sections were pathologically and clinically diagnosed as CD or ITB.Paraffin wax-embedded tissue sections were attached to a metal coating and measured using attenuated total reflectance fourier transform infrared spectroscopy at mid-infrared wavelengths combined with XGBoost for differential diagnosis.RESULTS The results showed that the paraffin wax-embedded specimens of CD and ITB were significantly different in their spectral signals at 1074 cm^(-1) and 1234 cm^(-1) bands,and the differential diagnosis model based on spectral characteristics combined with machine learning showed accuracy,specificity,and sensitivity of 91.84%,92.59%,and 90.90%,respectively,for the differential diagnosis of CD and ITB.CONCLUSION Information on the mid-infrared region can reveal the different histological components of CD and ITB at the molecular level,and spectral analysis combined with machine learning to establish a diagnostic model is expected to become a new method for the differential diagnosis of CD and ITB. 展开更多
关键词 Infrared spectroscopy Machine learning Intestinal tuberculosis Crohn’s disease Differential diagnosis Inflammatory bowel disease
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Comparative study on phase transition behaviors of fractional molecular field theory and random-site Ising model
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作者 刘婷玉 赵薇 +3 位作者 王涛 安小冬 卫来 黄以能 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期536-541,共6页
Fractional molecular field theory(FMFT)is a phenomenological theory that describes phase transitions in crystals with randomly distributed components,such as the relaxor-ferroelectrics and spin glasses.In order to ver... Fractional molecular field theory(FMFT)is a phenomenological theory that describes phase transitions in crystals with randomly distributed components,such as the relaxor-ferroelectrics and spin glasses.In order to verify the feasibility of this theory,this paper fits it to the Monte Carlo simulations of specific heat and susceptibility versus temperature of two-dimensional(2D)random-site Ising model(2D-RSIM).The results indicate that the FMFT deviates from the 2D-RSIM significantly.The main reason for the deviation is that the 2D-RSIM is a typical system of component random distribution,where the real order parameter is spatially heterogeneous and has no symmetry of space translation,but the basic assumption of FMFT means that the parameter is spatially uniform and has symmetry of space translation. 展开更多
关键词 phase transition molecular field theory Ising model Monte Carlo
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Enhancing multifunctional photocatalysis with acetate-assisted cesium doping and unlocking the potential of Z-scheme solar water splitting
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作者 Mengmeng Ma Jingzhen Li +6 位作者 Xiaogang Zhu Kong Liu Kaige Huang Guodong Yuan Shizhong Yue Zhijie Wang Shengchun Qu 《Carbon Energy》 SCIE EI CAS CSCD 2024年第3期178-195,共18页
Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion ... Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make sense.For this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation.The optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an hour.The penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are fabricated.This atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic capacity.Furthermore,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN systems.This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis. 展开更多
关键词 acetate-assisted cesium doping MULTIFUNCTIONAL PHOTOCATALYSIS Z-scheme
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High-order harmonic generation of ZnO crystals in chirped and static electric fields
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作者 张玲玉 何永林 +5 位作者 谢卓璇 高芳艳 徐清芸 葛鑫磊 罗香怡 郭静 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期335-343,共9页
High harmonic generation in ZnO crystals under chirped single-color field and static electric field are investigated by solving the semiconductor Bloch equation(SBE). It is found that when the chirp pulse is introduce... High harmonic generation in ZnO crystals under chirped single-color field and static electric field are investigated by solving the semiconductor Bloch equation(SBE). It is found that when the chirp pulse is introduced, the interference structure becomes obvious while the harmonic cutoff is not extended. Furthermore, the harmonic efficiency is improved when the static electric field is included. These phenomena are demonstrated by the classical recollision model in real space affected by the waveform of laser field and inversion symmetry. Specifically, the electron motion in k-space shows that the change of waveform and the destruction of the symmetry of the laser field lead to the incomplete X-structure of the crystal-momentum-resolved(k-resolved) inter-band harmonic spectrum. Furthermore, a pre-acceleration process in the solid four-step model is confirmed. 展开更多
关键词 high-order harmonic generation the semiconductor Bloch equation k-resolved inter-band harmonic spectrum four-step semiclassical model
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Non-monotonic behavior of jam probability and stretchedexponential distribution in pedestrian counterflow
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作者 Ze-Hao Chen Zhi-Xi Wu Jian-Yue Guan 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期259-266,共8页
We adopt a floor field cellular automata model to study the statistical properties of bidirectional pedestrian flow movingin a straight corridor. We introduce a game-theoretic framework to deal with the conflict of mu... We adopt a floor field cellular automata model to study the statistical properties of bidirectional pedestrian flow movingin a straight corridor. We introduce a game-theoretic framework to deal with the conflict of multiple pedestrians tryingto move to the same target location. By means of computer simulations, we show that the complementary cumulative distributionof the time interval between two consecutive pedestrians leaving the corridor can be fitted by a stretched exponentialdistribution, and surprisingly, the statistical properties of the two types of pedestrian flows are affected differently by theflow ratio, i.e., the ratio of the pedestrians walking toward different directions. We also find that the jam probability exhibitsa non-monotonic behavior with the flow ratio, where the worst performance arises at an intermediate flow ratio of around0.2. Our simulation results are consistent with some empirical observations, which suggest that the peculiar characteristicsof the pedestrians may attributed to the anticipation mechanism of collision avoidance. 展开更多
关键词 traffic and crowd dynamics evolutionary game theory
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Progress of Electrocatalytic Technology in Treating Organic Chemical Wastewater
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作者 Lun Deng Hemei Wang 《Expert Review of Chinese Chemical》 2024年第1期9-14,共6页
In recent years,extensive research has been conducted on the preparation of high catalytic performance electrodes and the development of electrocatalytic water treatment processes.This article introduces the basic pri... In recent years,extensive research has been conducted on the preparation of high catalytic performance electrodes and the development of electrocatalytic water treatment processes.This article introduces the basic principles of electrochemical water treatment,the preparation of electrode materials,and the research progress of electrocatalytic technology for degrading organic chemical wastewater.It analyzes the problems faced by electrocatalytic degradation of organic chemical wastewater and looks forward to the development trend of electrocatalytic technology in the field of organic chemical wastewater treatment. 展开更多
关键词 ELECTROCATALYSIS electrode preparation organic chemical wastewater water treatment
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Deep-ultraviolet photonics for the disinfection of SARS-CoV-2 and its variants(Delta and Omicron)in the cryogenic environment 被引量:1
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作者 Wenyu Kang Jing Zheng +7 位作者 Jiaxin Huang Lina Jiang Qingna Wang Zhinan Guo Jun Yin Xianming Deng Ye Wang Junyong Kang 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2023年第9期16-29,共14页
Deep-ultraviolet(DUV)disinfection technology provides an expeditious and efficient way to suppress the transmission of coronavirus disease 2019(COVID-19).However,the influences of viral variants(Delta and Omicron)and ... Deep-ultraviolet(DUV)disinfection technology provides an expeditious and efficient way to suppress the transmission of coronavirus disease 2019(COVID-19).However,the influences of viral variants(Delta and Omicron)and low temperatures on the DUV virucidal efficacy are still unknown.Here,we developed a reliable and uniform planar light source comprised of 275-nm light-emitting diodes(LEDs)to investigate the effects of these two unknown factors and delineated the principle behind different disinfection performances.We found the lethal effect of DUV at the same radiation dose was reduced by the cryogenic environment,and a negative-U large-relaxation model was used to explain the difference in view of the photoelectronic nature.The chances were higher in the cryogenic environment for the capture of excited electrons within active genetic molecules back to the initial photo-ionised positions.Additionally,the variant of Omicron required a significantly higher DUV dose to achieve the same virucidal efficacy,and this was thanks to the genetic and proteinic characteristics of the Omicron.The findings in this study are important for human society using DUV disinfection in cold conditions(e.g.,the food cold chain logistics and the open air in winter),and the relevant DUV disinfection suggestion against COVID-19 is provided. 展开更多
关键词 LED UV-C III-nitrides semiconductors photoelectronic COVID-19 virucidal efficacy
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A novel lattice model integrating the cooperative deviation of density and optimal flux under V2X environment
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作者 彭光含 罗春莉 +1 位作者 赵红专 谭惠丽 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第1期626-633,共8页
A novel lattice hydrodynamic model is proposed by integrating the cooperative deviation of density and optimal flux under vehicle to X(V2X) environment. According to the theoretical analysis, the stability conditions ... A novel lattice hydrodynamic model is proposed by integrating the cooperative deviation of density and optimal flux under vehicle to X(V2X) environment. According to the theoretical analysis, the stability conditions and the mKdV equations affected by the cooperative deviation of traffic information are explored. And the density wave, hysteresis loop and energy consumption of the traffic flow have been investigated via numerical simulation. The results indicate that the cooperative deviation of density and optimal flux can effectively alleviate the traffic congestion. More importantly, our new consideration can reduce fuel consumption and exhaust emission under the V2X environment. 展开更多
关键词 traffic flow lattice hydrodynamic model cooperative deviation
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Inverse Design and Experimental Verification of Metamaterials for Thermal Illusion Using Genetic Algorithms
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作者 何宗堽 袁坤 +1 位作者 熊国欢 王健 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第10期73-77,共5页
Thermal metamaterials offer a promising avenue for creating artificial materials with unconventional physical properties,such as thermal cloak,concentrator,rotator,and illusion.However,designs and fabrication of therm... Thermal metamaterials offer a promising avenue for creating artificial materials with unconventional physical properties,such as thermal cloak,concentrator,rotator,and illusion.However,designs and fabrication of thermal metamaterials are of challenge due to the limitations of existing methods on anisotropic material properties.We propose an evolutionary framework for designing thermal metamaterials using genetic algorithm optimization.Our approach encodes unit cells with different thermal conductivities and performs global optimization using the evolution-inspired operators.We further fabricate the thermal functional cells using 3D printing and verify their thermal illusion functionality experimentally.Our study introduces a new design paradigm for advanced thermal metamaterials that can manipulate heat flows robustly and realize functional thermal metadevices without anisotropic thermal conductivity.Our approach can be easily applied to fabrications in various fields such as thermal management and thermal sensing. 展开更多
关键词 ANISOTROPIC THERMAL INVERSE
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Timing and Single-pulse Study of Pulsar J1909+0122 Discovered by CRAFTS
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作者 Yutong Chen Pei Wang +27 位作者 Di Li Erbil Gügercinoğlu Rushuang Zhao Lingqi Meng Jianping Yuan Jiarui Niu Weiwei Zhu Yi Feng Chenchen Miao Chenhui Niu Qingdong Wu Na Wang Shen Wang Xiaoyao Xie Mengyao Xue Jumei Yao Mao Yuan Shanping You Xuhong Yu Youling Yue Jie Zhang Junshuo Zhang Lei Zhang Yabiao Wang Zhenye Gan Yuxi Li Zhongyi Sun Chengjie Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第8期319-331,共13页
We report the discovery of PSR J1909+0122 by the Five-hundred-meter Aperture Spherical Radio Telescope(FAST)as part of the Commensal Radio Astronomy FAST Survey.PSR J1909+0122 has a spin period of 1.257 s and a disper... We report the discovery of PSR J1909+0122 by the Five-hundred-meter Aperture Spherical Radio Telescope(FAST)as part of the Commensal Radio Astronomy FAST Survey.PSR J1909+0122 has a spin period of 1.257 s and a dispersion measure of 186.2 pc cm^(-3).The averaged pulse profile shows two distinct components.We performed a single-pulse study based on a one-hour observation at 1.25 GHz on 2021 August 23.We used a threshold of 5σ_(ep) to measure the nulling fraction(NF)as 63%±1.5%.The longitude-resolved fluctuation spectra and fast Fourier transform spectra of the binary sequences revealed the quasi-periodicity of nulling with a period of 30 rotation periods.We examined the reliability of the periodicity by comparing it to random noise injection.The NF,E,and modulation periodicity P_(M) of PSR J1909+0122 were compared with other periodic nulling pulsars,showing that the source of J1909+0122 has the second largest NF in the population.Long-term timing observations over six months were used to derive the phase-connected ephemeris of this pulsar.The measured P and P values disfavor dipolar geometry for polar gap models,and the prediction for a space-charge-limited flow model in the case of inverse Compton scattering is only just above the death line.In this work,PSR J1909+0122 has revealed possible correlations between nulling behavior and pulsar properties,which will help to shed light on the pulsar emission mechanism and its temporal evolution in future observations. 展开更多
关键词 (stars:)pulsars general-(stars:)pulsars individual(PSR J1909+0122)-stars NEUTRON
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Modeling the performance of perovskite solar cells with inserting porous insulating alumina nanoplates
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作者 潘赵耀 杨金彭 沈小双 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期668-671,共4页
Peng et al.[Science 379683(2023)]reported an effective method to improve the performance of perovskite solar cells by using thicker porous insulator contact(PIC)-alumina nanoplates.This method overcomes the trade-off ... Peng et al.[Science 379683(2023)]reported an effective method to improve the performance of perovskite solar cells by using thicker porous insulator contact(PIC)-alumina nanoplates.This method overcomes the trade-off between the open-circuit voltage and the fill factor through two mechanisms:reduced surface recombination velocity and increased bulk recombination lifetime due to better perovskite crystallinity.From arguments of drift-diffusion simulations,we find that an increase in mobility and carrier recombination lifetime in bulk are the key factors for minimizing the resistance-effect from thicker PICs and achieving a maximum power conversion efficiency(PCE)at approximately 25%reduced contact area.Furthermore,the partially replacement of perovskite films with thicker PICs would result in a reduction in short-current density,but the relative low refractive index of the PICs imbedded into the high refractive index perovskite creates light trapping structures that compensate for this loss. 展开更多
关键词 perovskite solar cells NANOSTRUCTURE CRYSTALLINE mobility
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Interference of harmonics emitted by different tunneling momentum channels in laser fields
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作者 Ling-Yu Zhang Zhuo-Xuan Xie +2 位作者 Can Wang Xin-Lei Ge Jing Guo 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期366-372,共7页
By numerically solving the semiconductor Bloch equation(SBEs),we theoretically study the high-harmonic generation of ZnO crystals driven by one-color and two-color intense laser pulses.The results show the enhancement... By numerically solving the semiconductor Bloch equation(SBEs),we theoretically study the high-harmonic generation of ZnO crystals driven by one-color and two-color intense laser pulses.The results show the enhancement of harmonics and the cut-off remains the same in the two-color field,which can be explained by the recollision trajectories and electron excitation from multi-channels.Based on the quantum path analysis,we investigate contribution of different ranges of the crystal momentum k of ZnO to the harmonic yield,and find that in two-color laser fields,the intensity of the harmonic yield of different ranges from the crystal momentum makes a big difference and the harmonic intensity is depressed from all k channels,which is related to the interferences between harmonics from symmetric k channels. 展开更多
关键词 high-order harmonic generation the semiconductor Bloch equation k-resolvedinter-bandhar-monic spectrum four-step semiclassical model
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Electrically switchable helicity of light driven by the spin-orbit torque effect
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作者 Yongping Wei Yaping Wu 《Journal of Semiconductors》 EI CAS CSCD 2024年第11期10-12,共3页
The revolution in information sharing is fundamentally supported by the highly efficient processing,storage,and transmission of data[1].For the latter,energy consumption continuously increases with the rapid developme... The revolution in information sharing is fundamentally supported by the highly efficient processing,storage,and transmission of data[1].For the latter,energy consumption continuously increases with the rapid development of information and communication technology[2]. 展开更多
关键词 EFFECT latter LIGHT
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Influence of Perpendicular Magnetic Field on Apparent Density and Microstructure of Magnetic Fluid 被引量:8
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作者 LI Yan-Qin LI Xue-Hui 《Chinese Physics Letters》 SCIE CAS CSCD 2012年第10期204-208,共5页
The formula for a magnetic fluid's apparent density is derived based on Bernoulli's equation of magnetic fluid,and the distribution of the magnetic fluid's apparent density is measured by the intelligent a... The formula for a magnetic fluid's apparent density is derived based on Bernoulli's equation of magnetic fluid,and the distribution of the magnetic fluid's apparent density is measured by the intelligent apparatus of measuring a magnetic fluid's apparent density in an applied perpendicular magnetic field.Magnetic particle chain-like alignments are observed by a transmission electron microscope(TEM).Without an applied magnetic field,the magnetic fluid's density is equal everywhere and the distribution of magnetic particles is homogeneous and unordered.When magnetic induction and magnetic induction gradient gather strength in an applied perpendicular magnetic field,the magnetic fluid's apparent density increases gradually,and more chain-like structures are formed and aligned with the direction of the magnetic field.The results of magnetic particle alignments are correspondent with the distribution of the magnetic fluid's apparent density.Both of them result from particle-particle interactions and particle-carrier liquid interactions,which are eventually controlled by the applied magnetic induction and magnetic induction gradient distribution. 展开更多
关键词 MICROSTRUCTURE APPARENT MAGNETIC
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Phase transition, elastic and electronic properties of topological insulator Sb_2Te_3 under pressure: First principle study 被引量:5
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作者 卢清 张怀勇 +2 位作者 程艳 陈向荣 姬广富 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第2期348-354,共7页
The phase transition, elastic and electronic properties of three phases(phase Ⅰ,Ⅱ, and Ⅲ) of Sb_2Te_3 are investigated by using the generalized gradient approximation(GGA) with the PBESOL exchange–correlation ... The phase transition, elastic and electronic properties of three phases(phase Ⅰ,Ⅱ, and Ⅲ) of Sb_2Te_3 are investigated by using the generalized gradient approximation(GGA) with the PBESOL exchange–correlation functional in the framework of density-functional theory. Some basic physical parameters, such as lattice constants, bulk modulus, shear modulus,Young's modulus, Poisson's ratio, acoustic velocity, and Debye temperature Θ are calculated. The obtained lattice parameters under various pressures are consistent with experimental data. Phase transition pressures are 9.4 GPa(Ⅰ→Ⅱ) and 14.1 GPa(Ⅱ→Ⅲ), which are in agreement with the experimental results. According to calculated elastic constants, we also discuss the ductile or brittle characters and elastic anisotropies of three phases. Phases Ⅰ and Ⅲ are brittle, while phaseⅡ is ductile. Of the three phases, phaseⅡ has the most serious degree of elastic anisotropy and phase Ⅲ has the slightest one.Finally, we investigate the partial densities of states(PDOSs) of three phases and find that the three phases possess some covalent features. 展开更多
关键词 Sb2Ze3 phase transition elastic properties electronic properties
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First-principles study of the structural,mechanical and electronic properties of ZnX_2O_4(X=Al,Cr and Ga) 被引量:3
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作者 张良 姬广富 +1 位作者 赵峰 龚自正 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第4期408-414,共7页
This paper performs first-principles calculations to study the structural, mechanical and electronic properties of the spinels ZnA1204, ZnGa2O4 and ZnCr2O4, using density functional theory with the plane-wave pseudopo... This paper performs first-principles calculations to study the structural, mechanical and electronic properties of the spinels ZnA1204, ZnGa2O4 and ZnCr2O4, using density functional theory with the plane-wave pseudopotential method. Our calculations are in good agreement with previous theoretical calculations and the available experimental data. The studies in this paper focus on the evolution of the mechanical properties of ZnAl2O4, ZnGa2O4 and ZnCr2O4 under hydrostatic pressure. The results show that the cubic phases of ZnAl2O4, ZnCa2O4 and ZnCr2O4 become unstable at about 50 GPa, 40 GPa and 25 GPa, respectively. From analysis of the band structure of the three compounds at equilibrium volume, it obtains a direct band gap of 4.35 eV for ZnA1204 and 0.89 cV for ZnCr2O4, while ZnGa2O4 has an indirect band gap of 2.73 eV. 展开更多
关键词 first-principles calculation phase transition elastic constants BANDSTRUCTURE
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Elastic and Thermodynamic Properties of CdSe from First-Principles Calculations 被引量:3
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作者 TAN Jia-Jin CHENG Yan +1 位作者 ZHU Wen-Jun GOU Qing-Quan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第7期220-226,共7页
The lattice parameters, bulk modulus, phase transition pressure, and temperature dependencies of the elastic constants cij of CdSe are investigated by using the Cambridge Serial Total Energy Package (CASTEP) program... The lattice parameters, bulk modulus, phase transition pressure, and temperature dependencies of the elastic constants cij of CdSe are investigated by using the Cambridge Serial Total Energy Package (CASTEP) program in the frame of Density Functional Theory (DFT). It is found that the phase transitions from the ZB structure to the RS structure and from WZ structure to RS structure are 2.2 GPa and 2.8 GPa, respectively. Our results agree well with the available experimental data and other theoretical results. The aggregate elastic modulus (B, G, E, A ), the Poisson's ratio (v), the Griuneisen parameter (γ), the Debye temperature θD on pressure and temperature are also successfully obtained. 展开更多
关键词 elastic properties thermodynamic properties density functional theory CDSE
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Simulations of the flipping images and microparameters of molecular orientations in liquids according to the molecule string model 被引量:3
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作者 王丽娜 赵兴宇 +1 位作者 张丽丽 黄以能 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第8期392-397,共6页
The relaxation dynamics of liquids is one of the fundamental problems in liquid physics, and it is also one of the key issues to understand the glass transition mechanism. It will undoubtedly provide enlightenment on ... The relaxation dynamics of liquids is one of the fundamental problems in liquid physics, and it is also one of the key issues to understand the glass transition mechanism. It will undoubtedly provide enlightenment on understanding and calculating the relaxation dynamics if the molecular orientation flipping images and relevant microparameters of liquids are studied. In this paper, we first give five microparameters to describe the individual molecular string (MS) relaxation based on the dynamical Hamiltonian of the MS model, and then simulate the images of individual MS ensemble, and at the same time calculate the parameters of the equilibrium state. The results show that the main molecular orientation flipping image in liquids (including supercooled liquid) is similar to the random walk. In addition, two pairs of the parameters are equal, and one can be ignored compared with the other. This conclusion will effectively reduce the difficulties in calculating the individual MS relaxation based on the single-molecule orientation flipping rate of the general Glauber type, and the computer simulation time of interaction MS relaxation. Moreover, the conclusion is of reference significance for solving and simulating the multi-state MS model. 展开更多
关键词 relaxation dynamics glass transition Ising model molecular string
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First-principles investigations on elastic and thermodynamic properties of zinc-blende structure BeS 被引量:2
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作者 常景 陈向荣 +1 位作者 张伟 朱俊 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第4期1377-1382,共6页
In this paper the elastic and thermodynamic properties of the cubic zinc-blende structure BeS at different pressures and temperatures are investigated by using ab initio plane-wave pseudopotential density functional t... In this paper the elastic and thermodynamic properties of the cubic zinc-blende structure BeS at different pressures and temperatures are investigated by using ab initio plane-wave pseudopotential density functional theory method within the generalized gradient approximation (GGA). The calculated results are in excellent agreement with the available experimental data and other theoretical results. It is found that the zinc-blende structure BeS should be unstable above 60GPa. The thermodynamic properties of the zinc-blende structure BeS are predicted by using the quasi-harmonic Debye model. The pressure-volume-temperature (P - V - T) relationship, the variations of the thermal expansion coefficient α and the heat capacity Cv with pressure P and temperature T, as well as the Gruneisen parameter-pressure-temperature (γ- P - T) relationship are obtained systematically in the ranges of 0-90GPa and 0-2000K. 展开更多
关键词 density functional theory elastic constants thermodynamic properties Griineisen parameter BES
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Perturbation and Adiabatic Invariants of Mei Symmetry for Nonholonomic Mechanical Systems 被引量:2
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作者 DING Ning FANG Jian-Hui WANG Peng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4期594-596,共3页
Based on the concept of adiabatic invariant, the perturbation and adiabatic invariants of the Mei symmetry for nonholonomic mechanical systems are studied. The exact invariants of the Mei symmetry for the system witho... Based on the concept of adiabatic invariant, the perturbation and adiabatic invariants of the Mei symmetry for nonholonomic mechanical systems are studied. The exact invariants of the Mei symmetry for the system without perturbation are given. The perturbation to the Mei symmetry is discussed and the adiabatic invariants of the Mei symmetry for the perturbed system are obtained. 展开更多
关键词 Mei symmetry PERTURBATION adiabatic invariant nonholonomic mechanical system
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