bluuebunny/crossref_metadata_2025 huggingface dataset:
AN EIGEN MATRIX METHOD FOR OBTAINING THE BAND STRUCTURE OF PHOTONIC CRYSTALS
Authors: WANG HUI  , LI YONG-PING  ,   (1)中国科学技术大学物理系,合肥230026; (2)中国科学技术大学物理系,合肥230026;中国科学技术大学结构分析开放实验室,合肥230026
Published: December 2020

An eigen matrix method is reported to obtain the band structure of one-dimensional(1D) photonic crystals. Using this method, we have calculated the band structures of 1D crystals consisting of components with different dielectric constants and geometric structures. It can also be extended to a case where the dielectric constant is dependent on the frequency of the incident light.
LASER-INDUCED LATTICE DEFORMATION OF POROUS SILICON REVEALED BY RAMAN AND PHOTOLUMINESCENCE SPECTROSCOPIES
Authors: LIANG ER-JUN  , CHAO MING-JU  ,   郑州大学河南省激光应用技术重点实验室,郑州450052
Published: December 2020

Raman and photoluminescence spectroscopies fo the porous silicon prepared in a hydrothermal solution with addition of titanium have been studied. Only a sharp single band near 520cm-1 appears in the Raman spectrum of the porous silicon when the exciting laser power is low and shifts to the red side with the increase of the laser power. If the laser power is increased to a critical value, the Raman band splits into two bands while the photoluminescence band splits also and the intensity of it increases enormously. We assign the two Raman bands to the lattice deformation-induced non-degeneracy of the LO and TO phonons. The laser-induced lattice deformation may result in the transformation of the porous silicon from a linear to a nonlinear optical material with a large laser-induced nonlinear optical absorption coefficient. It is found that the laser-induced transformation in the porous silicon is a reversible process. This may implicate some new applications of this material.
THE EFFICIENCY OF THE FORMATION AND FISSION OF POLARON-EXCITONS IN POLYMER LIGHT-EMITTING DEVICES
Authors: LI HONG-JIAN  , PENG JING-CUI  , XU XIE-MEI  , QU SHU  , XIA HUI  ,   (1)湖南大学光电子材料研究所,长沙410082; (2)湖南大学光电子材料研究所,长沙410082;中南大学材料科学系,长沙410083
Published: December 2020

The processes of formation and fission of polaron-excitons in polymer light-emitting devices are investigated in detail. A theoretical model and a complete analytic function for polaron-excitions fission is proposed. The influences of applied bias, temperature and dopant concentrations on recombination internal quantum efficiency are thoroughly studied. This theoretical model could explain the experimental phenomena.
GIANT TUNNELING MAGNETORESISTANCE IN NANOSTRUCTURED ZnxFe3-xO4-α-Fe2O3 POLYCRYSTALLINE MATERIAL
Authors: DU YOU-WEI  , CHEN PENG  , ZHU JIAN-MIN  , XING DING-YU  ,   南京大学固体微结构物理国家重点实验室物理系,南京210093
Published: December 2020

Giant tunneling magnetoresistance effect (TMR) as large as 1280% at 4.2K and 158% at 300K was observed in Zn0.41Fe2.59O4-α-Fe2O3 polycrystalline sample. The Zn0.41Fe2.59O4 grains are separated by insulating α-Fe2O3 thin layer boundaries, The pattern of nanostructure has been verified by TEM and HREM and the thickness of α-Fe2O3 boundary is about 6-7nm. The huge TMR is attributed to the high spin-polarization of Zn0.41Fe2.59O4 grains and insulating antiferromagnetic α-Fe2O3 thin layer. The ZnxFe3-xO4 ferrite is a new type half-metallic material with a huge TMR at room temperature is interesting to further study in future.
A NOVEL CONTROL METHOD FOR DISCRETE MAP CHAOTIC SYSTEM
Authors: WANG GAI-YUN  , YU JUE-BANG  , GU TIAN-XIANG  ,   (1)电子科技大学自动化系,成都610054; (2)电子科技大学自动化系,成都610054,桂林电子工业学院计算机学系,桂林541004
Published: December 2020

Based on the delayed feedback control idea, a novel prediction feedback control method for discrete chaotic system is presented. The method is illustrated in detail and the computer simulation is carried out. The simulation result is compared with that of delayed feedback control and it is shown that the proposed method is more effective for controlling fixed point of chaotic system.
THE DYNAMIC MODULATION FOR GAIN PERFORMANCE IN MULTI-SEGMENT Nd:GLASS DISK LASER AMPLIFIERS
Authors: ZHANG HUA  , FAN DIAN-YUAN  ,   (1)南通师范学院物理系,南通226007; (2)中国科学院上海光学精密机械研究所,上海201800
Published: December 2020

Based upon the instantaneous output spectra of a xenon flashlamp, we have constructed a unique dynamic modeling program to predict the gain performance of multi segment Nd:glass laser amplifiers. The model, which includes all the dynamic modulations from flashlamp discharging to laser output, may be used in the laser amplifier system optimization. The gain uniformity in the horizontal direction is investigated with the modeling program. The amplified spontaneous emission inside a laser slab first increases the overall decay rate and thereby decreases the stored energy at the slab edges. The stored energy density at the slab center is higher than that at the slab edges when the explosion fraction of the flashlamp becomes large. The influences of the disk thickness and Nd2O3 doping level on gain performance are also studied with the modeling program. The stored fluence is determined by the doping-thickness products (Nd ion concentration ×slab thickness)in the multi-segment amplifiers slab, and the details are also given.
RADIATION EFFECTS OF MOS DEVICE AT LOW DOSE RATE AND LOW TEMPERATURE
Authors: ZHANG TING-QING  , LIU CHUAN-YANG  , LIU JIA-LU  , WANG JIAN-PING  , HUANG ZHI  , XU NA-JUN  , HE BAO-PING  , PENG HONG-LUN  , YAO YU-JUAN  ,   (1)西安电子科技大学微电子学研究所,西安710071; (2)西北核技术研究所,西安710024
Published: December 2020

Effects of irradiation dose rates and irradiation temperature are investigated for MOS device under γ-rays. Threshold voltage shift is compared after the MOS devices are radiated at different dose rates and different temperatures. At low dose rate,interface trap formation is affected by the irradiation time and H+ induced in the oxide,the longer the device is radiated and the greater the number of induced H+,the more the interface trap. The effects of temperature on radiation response are related to the time of interface trap formation,it takes more time to form interface trap at low temperatures.
The self-organized segregation effect of evolutionary minority game with imitation
Authors: Quan Hong-Jun  , Wang Bing-Hong  , Yang Wei-Song  , Wang Wei-Ning  , Luo Xiao-Shu  ,   (1)广西师范大学物理与电子科学系,桂林541004; (2)中国科学技术大学近代物理系及非线性科学中心,合肥230026; (3)中国科学技术大学近代物理系及非线性科学中心,合肥230026华南理工大学应用物理系,广州510641
Published: December 2020

A variant of the evolutionary minority game is proposed. Agents' strategies given by probabilities p can be changed by imitation. Numerical results show that the agents evolve into a state in which they selfsegregate into opposite groups characterized by extreme behaviours. The evolution by imitation can considerably enhance the system's coordination.
Four kinds of raising and lowering operators of the Landau system
Authors: Chen Chang-Ju  , Tian Xu  ,   (1)武汉理工大学理学院,武汉430070; (2)武汉理工大学自动化学院,武汉430070
Published: December 2020

Using the centre operator and the initial mechanical momentum operator, four kinds of raising and lowering operators of a Landau system (planar charged particle moving in a uniform magnetic field) were derived and corresponding selection rules and conserved quantum number were discussed.
A study on an improved Nagel-Schreckenberg traffic flow -model with open boundary conditions
Authors: Tian Hui-Li  , Liu Mu-Ren  , Kong Ling-Jiang  ,   广西师范大学物理与电子科学系,桂林541004
Published: December 2020

Using the improved Nagel-Schreckenberg traffic model with open boundary conditions,we present the fundamental diagrams of traffic flow under different parameters by numerical simulation.It turns out that the traffic flow of the improved Nagel-Schrec-kenberg model is greater than that of the Nagel-Schreckenberg model,then we analyse the characters and critical points of the transition from free flow phase to maximum current phase and the transition from jamming phase to free flow phase.
Theoretical calculation of the fine-structure and term energy of the excited states 1s~2 nd(n=3,4,5 of lithium-like systems
Authors: Ge Zi-Ming  , Lv Zhi-Wei  , Wang Zhi-Wen  , Zhou Ya-Jun  ,   (1)哈尔滨工业大学光电子技术研究所,哈尔滨150001; (2)吉林大学原子与分子物理研究所,长春130023; (3)辽宁师范大学物理系,大连110629
Published: December 2020

The fullcore plus correlation (FCPC) and the minimiziation of the expectation value of the Hamiltonian method is extended to calculate the nonreltivistic energies and the wave functions of 1s~2 nd(n=3,4,5) states for the lithium like systems from Z=11 to 20. The mass-polarization and the relativistic correction including the kinetic-energy correction, the Darwin term, the electron-electron contact term, and the orbitorbit interaction are calculated perturbatively as the first-order correction. The contribution from quantum electrodynamics (QED) is also included by using the effective nuclear charge formula. The excited energies, finestructure, and the termenergy are given and compared with other theoretical calculation and experimental results. It is shown that the correlative wave in the FCPC method embodies very well the strong correlation effect between the 1s~2 core and the valence electron.
Possibility of atmospheric pressure glow discharge in air
Authors: Wang Xin-Xin  , Lu Ming-Ze  , Pu Yi-Kang  ,   清华大学电机工程系,北京100084
Published: December 2020

The atmospheric pressure discharge in an air gap between two dielectric barrier electrodes has been studied experimentally and the development of an electron avalanche in such an air gap was simulated numerically. The results show that, while it is possible to obtain glow discharge in an air gap not longer than 2 mm, the streamer discharge could only be obtained in an air gap longer than 5 mm if no methods could be used to lower the electric field when discharging. The "iontrapping mechanism", which was said to be responsible for the atmospheric pressure glow discharge, was not verified in the experiments.
Surface energy of the biaxial nematic liquid crystal
Authors: Liu Hong  ,   南京师范大学物理系,南京210097
Published: December 2020

In this paper, two forms of surface energy of the biaxial nematic liquid crystal are derived. One is related to the deviation of surface directors with respect to the easy axes０,０ and０in the surface. The other is related to the surface order parameter matrix Q. The relations between the two forms are derived. In the former one, four independent coefficients are involved while in the latter one, only two independent coefficients are involved. In order to inspect the physical meaning of these coefficients, a simple model of molecular interaction between liquid crystal and boundary plate is proposed. In the model, the biaxial orientation of molecules along０and 0 is assumed to arise from two perpendicular mean fields along 0,０competing with each other. In three geometric features of Freedericksz transition where and rotate around 0， [WTHX][AKb^][WTBZ] and [WTHX][AKc^D][WTBZ] around [WTHX][AKa^D][WTBZ]0,[WTHX][AKc^D][WTBZ] and [WTHX][AKa^D][WTBZ] around [WTHX][AKb^][WTBZ]０ respectively, possible experimental measurements of surface anchoring coefficients [WTBX]Wa,Wb[WTBZ] and [WTBX]Wc[WTBZ] involved in the distortions are explored.
Ｓｏｌｉｔｏｎｐｒｏｐｅｒｔｉｅｓｏｆｌｉｇｈｔｔｒａｎｓｐｏｒｔａｔｉｏｎｉｎｉｏｎｉｃｃｒｙｓｔａｌｓｇｅｎｅｒａｔｅｄｂｙｎｏｎｌｉｎｅａｒｅｆｆｅｃｔｓ
Authors: Niu Jia-Sheng  , Ma Ben-Kun  ,   (1)北京师范大学低能核物理研究所,北京100875;北京师范大学物理系,北京100875; (2)北京师范大学物理系,北京100875
Published: December 2020

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Ｓｔａｂｉｌｉｔｙｄｉａｇｒａｍｓｆｏｒｓｉｎｇｌｅ ｅｌｅｃｔｒｏｎｔｒａｎｓｉｓｔｏｒｓ
Authors: Wu Fan  , Wang Tai-Hong  ,   中国科学院物理研究所,北京100080
Published: December 2020

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Novel multi-soliton solutions of the breaking soliton equation
Authors: Zhang Jie-Fang  , Guo Guan-Ping  ,   (1)浙江师范大学教育科学与技术学院，金华  321004; (2)浙江师范大学数理与信息科学学院，金华  321004
Published: December 2020

Hirota bilinear method is a very effective method for solving nonlinear evolution equations. In this paper, by further generalizing this method, we obtain novel multi-soliton solutions of (2+1)-dimensional breaking soliton equation.
The new doubly-periodic solutions for nonlinear coupled scalar field equations( Ⅰ)
Authors: Li De-Sheng  , Zhang Hong-Qing  ,   (1)大连理工大学应用数学系,大连  116024; (2)大连理工大学应用数学系,大连  116024;沈阳工业大学理学院，沈阳  110023
Published: December 2020

In this paper, we obtained five kinds of new doubly-periodic solutions by using sinh-Gordon equation expansion method for nonlinear coupled scalar field equations which show physical significance and application value. In degeneration, we can obtain the new solitary wave solutions and trigonometric function solutions. The results showed that the equation has plenty of constructions of solutions, the physical phenomena of the physical model which the equation described, will be the object many physicists and mathematicians further explore.
Analysis for the propagation of evanescent waves and the photo tunneling effect in a multi-layered structure containing materials with negative refractive index
Authors: Chen Long  , He Sai-Ling  , Shen Lin-Fang  ,   浙江大学光学仪器国家重点实验室,光与电磁波研究中心,杭州  310027
Published: December 2020

The propagation properties of evanescent waves in a multi-layered structure containing materials with negative refractive index are analyzed. The decay or magnification of the amplitude of evanescent waves in different situations is explained analytically in detail. In particular, the influence of the dissipation of the negative refractive index medium on the photon tunneling effect is discussed. The propagation and energy storage of evanescent waves are shown clearly by using the incidence of a Gauss beam.
The influence of interface layer characteristics on Lamb waves in layered anisot ropic media
Authors: Zhang Hai-Yan  , Liu Zhen-Qing  , Ma Xiao-Song  ,   (1)上海大学通信与信息工程学院，上海  200072; (2)同济大学声学所，上海  200092
Published: December 2020

In this paper, the spring model for the anisotropic interface layer is built and introduced to the global matrix technique that is popularly used for analyzing layered composites. In introducing the spring interface condition, the philosophy adopted is to incorporate it with a minimum disruption to the program structur e, particularly the assembly of the global matrix. The spring interface has ther efore been introduced as a "material layer". This layer has material constants w hich govern the stiffness across it and has zero thickness. The layer can be bui lt into the appropriate location in the global matrix without making any changes in the other layers of the system. Numerical computations for the Lamb wave dis persion curves in two-layered anisotropic composite media with different interfa ce conditions including rigid connection, slip connection, and complete disbond are made，and plots of the through-thickness particle displacement distributions of Lamb modes for the rigid bond interface and slip bond interface are compared .
Ni/Ni3Al grain boundary of Ni-based single superalloys: molecular dyn amics simulation
Authors: Wen Yu-Hua  , Zhu Tao  , Cao Li-Xia  , Wang Chong-Yu  ,   (1)钢铁研究总院功能材料研究所，北京  100081; (2)清华大学物理系，北京  100084; (3)清华大学物理系，北京  100084;钢铁研究总院功能材料研究所，北京  100081
Published: December 2020

In this paper, molecular dynamics simulations are used to study the structure of Ni-based single superalloys with a {100} Ni/Ni3Al grain boundary. Tw o differe nt initial models are relaxed at 300K using Finnis-Sinclair-type potential. Our simulations reveal that the misfit energy due to the difference of their lattice constants is released not by long-range lattice misfit but by forming dislocati ons in local regions. Due to the surrounding differences of Ni3Al pha se in Ni-based phase, the dislocations formed are different.
A simulation study of 6H-SiC Schottky barrier source/drain MOSFET
Authors: Wang Yuan  , Zhang Yi-Men  , Zhang Yu-Ming  , Tang Xiao-Yan  ,   西安电子科技大学微电子研究所，西安  710071
Published: December 2020

A novel SiC metal-oxide-semiconductor field-effect transistor (SiC SBSD-MOSFET) with Schottky barrier contacts for source and drain is presented in this paper. This kind the device gives a fabrication advantage of avoiding the steps of ion implantation and annealing at high temperatures of the conventional SiC MOSFET. Also It has no problems of crystal damage caused by ion implantation and low activation rate of implanted atoms. The operational mechanism of this device is analyzed and its characteristics are comparable to the conventional SiC MOSFET from the simulation with MEDICI. The effects of different metal workfunctions, oxide thickness, and gate length on the device performance are discussed.
Large effective area highTc rf SQUID
Authors: Liu Xin-Yuan  , Xie Fei-Xiang  , Meng Shu-Chao  , Ma Ping  , Yang Tao  , Nie Rui-Juan  , Wang Shou-Zheng  , Wang Fu-Ren  , Dai Yuan-Dong  ,   (1)人工微结构和介观物理国家重点实验室，北京大学物理学院，北京  100871; (2)人工微结构和介观物理国家重点实验室，北京大学物理学院，北京  100871;北京大学信息科学技术学院，北京  100871
Published: December 2020

We have designed and fabricated a new type of highTc rf SQUID sensor. A high T c coplanar superconducting resonator and a large area high Tc superconductin g film concentrator have been used simultaneously. With a　large effective area and low white flux noise, we have achieved a flux noise of 2.1×10-5 0 /Hz and a magnetic field sensitivity of 34fT/Hz in white noise range, respective ly, using an effective area of 1.27 mm2 concentrator on a 15 mm×15 m m substra te. This design can be easily applied to higher frequency high Tc rf SQUID system.
The dc Josephson current in double ferromagnet-superconductor tunnel junctions
Authors: Li Xiao-Wei  ,   淮阴师范学院物理系,淮安  223001
Published: December 2020

Using Bogoliubov_de Gennes equations,we obtain the self_consistent equation in a ferromagnetic superconductor. Taking into account the rough interface scatterin g effects, within Bogoliubov_de Gennes equations and Furusaki_Tsukada formula we calculate the dc Josephson current in the double ferromagnet_superconductor tun nel junctions. It is found that dc Josephson currents in FS/I/FS are suppressed by the ferromagnetic exchange interaction for weak barrier strength and weak rou gh interface scattering strength. The only exception that the dc Josephson curre nts increase with the ferromagnetic exchange interaction occurs if all three con ditions are satisfied: at low temperature, for strong barrier strength or strong rough interface scattering strength, and in an antiparallel configuration.
In-situ monitoring of the growth of oxide thin films in PLD using high-pressure reflection high energy electron diffraction
Authors: Chen Ying-Fei  , Peng Wei  , Li Jie  , Chen Ke  , Zhu Xiao-Hong  , Wang Ping  , Zeng Guang  , Zheng Dong-Ning  , Li Lin  ,   中国科学院物理研究所,超导国家重点实验室，北京  100080
Published: December 2020

Reflection high-energy electron diffraction (RHEED) is very surface sensitive and often used for the analysis and monitoring of thin film growth in ultrahigh vacuum deposition system (for instance, Molecular Beam Epitasis). In order to in-situ monitor the growth of oxide thin films at high oxygen pressure up to 50Pa, a high-pressure RHEED designed and fabricated by our group was used for first time in our pulsed laser deposition system (PLD). Using the PLD system the Nb-doped SrTiO3 (STNO) and Y1Ba2Cu3O7 (YBCO) thin films have been epitaxially grown on SrTiO3 (001) substrates. T he RHEED patterns of the STNO and YBCO films and the oscillation of the intensity of the pattern have been measured by the high-pressure RHEED during deposition. In addition,the surface morpholoyg of the films and the dynamic analysis of film growth process were discussed.
Structure and Curie temperature of Y2(Fe1-x-y,Coy,Crx)17 compounds
Authors: Hao Yan-Ming  , Zhao Wei  , Gao Yan  ,   (1)东北林业大学，哈尔滨  150040; (2)天津师范大学物理系，天津  300074
Published: December 2020

The structure and Curie temperature of Y2(Fe1-x-y,Coy ,Crx)17 c ompounds have been investigated by means of x_ray diffraction and magnetization measurement. The Y2(Fe1-x-y,Coy,Crx) 17 compounds have a hexago nal Th2Ni17_type structure. With increasing x, the unit_ce ll volumes of Y2Fe17-xCrx and Y2CoFe16-xCrx compounds have a small decreas e initially, followed by a greater decrease. It is proved that the magnetic inte raction of Fe atoms at 4f sites of Y2Fe17 compound is anti ferromagnetic by studying the variation of Curie temperature of Y2(Fe1-x-y,Coy,Crx )17 compounds. The result also shows that a few Co and Cr atoms subst ituti ng for Fe atoms can enhance Curie temperature of Y2(Fe1-x-y,Coy,Crx)17 obviously.
Jacobi elliptic function expansion method applied to long-short wave interaction equations
Authors: Guo Guan-Ping  , Zhang Jie-Fang  ,   (1)上海大学应用数学和力学研究所,上海  200072;浙江师范大学非线性物理研究所,金华  321004; (2)浙江师范大学教育科学与技术学院,金华  321004
Published: December 2020

In this paper,the Jacobi elliptic function method is generalized to study nonlinear evolution system. The envelope periodic solutions of long-short wave interaction equation are obtained. The solitary wave solutions for this model are also given under some conditions.
The propagation of solitons in an inhomogeneous dusty plasma
Authors: Hong Xue-Ren  , Duan Wen-Shan  , Sun Jian-An  , Shi Yu-Ren  , Lü Ke-Pu  ,   西北师范大学物理与电子工程学院,兰州  730070
Published: December 2020

The propagation of solitons in an inhomogeneous dusty plasma composed of two kinds of dust grains with different masses is investigated by using the reductive perturbation technique. In the lowest order, if the interface of the two kinds of dust grains is discontinuous, the transmission and reflection waves can be both described by the KdV equation. The numbers and amplitudes of both transimtted and reflected solitons from an incident soliton are given analytically for this case. If the interface of the two kinds of dust grains is continuous, neglecting the reflection, the nonlinear dust acoustic wave can be described by a KdV-type equation in the lowest order. The amplitudes, propagating velocities of these quasi-solitons for this case are also given analytically in this paper.
The evolution property of three-body entanglement measure in Tavis-Cummings mode l
Authors: Zuo Zhan-Chun  , Xia Yun-Jie  ,   曲阜师范大学物理系,曲阜  273165
Published: December 2020

This paper studies the quantum entanglement of the Tavis-Cummings model for two steady identical two-level atoms interac-ting with a single-mode field. Whe n the field is vacuum and the two atoms stay in Einstein-Podolsky-Rosem entangle d state or disentangled state initially, we obtain that the system will evol ve to a three-body approximate W entangled state. The entanglement measure will change with the variation of system initial state, coupling coefficients, detuni ng degree and atomic population inversion. It should be noted that the atomic co upling coefficient exhibits the nonlinear effect and the entanglement measure os cillates periodically in accordance with atomic population inversion.
Perturbation to the energy of Gaussian beam by a doubly polarized weak gravita tional plane wave in a static magnetic field
Authors: Li Fang-Yu  , Shi Dong-Ping  , Dai Hong-Xia  ,   (1)重庆大学物理系，重庆  400044; (2)重庆大学物理系，重庆  400044;重庆工商大学物理系，重庆  400033; (3)重庆大学物理系，重庆  400044;重庆渝西学院物理系，重庆  402168
Published: December 2020

First-order and second-order perturbations to the energy of Gaussian beam by a doubly polarized weak gravitational plane wave in static magnetic fields are discussed.The results of numerical estimation show that the perturbation to Gaussian beams by weak gravitational plane waves is very small,i.e.the total energy of the background fields would not change obviously in the influence of gravitational waves,but the perturbative power flux produced in the local region may be observable.
Relaxation rate and stochastic resonance of a single-mode nonlinear optical syst em
Authors: Kang Yan-Mei  , Xu Jian-Xue  , Xie Yong  ,   西安交通大学建筑工程与力学学院非线性动力学研究所，西安  710049
Published: December 2020

The variational method is applied to a single-mode stochastic nonlinear optical system and the dependence of its relaxation rate and spectral amplification factor on the noise intensity based on the linear response theory is investigated.The investigation shows that when the biased input is vanishing,the relaxation rate has different dependence in monostable and multistable cases.The investigation also shows that the stochastic resonance occurs in one-dimensional symmetric monostable potential,and the possible condition for it is pointed out.
A car-following model with stochastically considering the relative velocity in a traffic flow
Authors: Xue Yu  ,   广西大学物理系,南宁  530004;上海大学上海市应用数学与力学研究所，上海  200072
Published: December 2020

In this paper, the car-following model with stochastically considering the relative velocity in a traffic flow is presented through investigating the vehicle a cceleration process with uncertainty. The stability criterion superior to the Ba ndo's model is derived by the linear stability analysis. The density wave is inv estigated analytically with the perturbation method. The results show that the o ccurrence of traffic jamming transitions can be described by the kink solution o f the modified Korteweg-de Vries equation. The effects of stochastic relative ve locity on the traffic flow are simulated and analyzed. It is shown that the chan ge rate of velocity in the new model is smaller than that of the Bando's model u nder the same condition and depends on the probability p. As the probability p i ncreases, a small initial disturbance does not magnify and influence on the traf fic flow, but fades away for a long time. The stable region in the new model is larger than in the Bando's model in the phase diagram. The existent initial hyst eresis in the new model will approach to a small region with the increase of tim e in the headway-velocity plot, which is exactly different from that in the Band o's model.In contrast,the hysteresis region in Bando's model will be continuousl y extended to cause traffic flow instability.
Study on the mechanism of light amplification in iron-doped lithium niobate crys tals
Authors: Zhao Hong-E  , Liu Si-Min  , Guo Ru  , Wang Da-Yun  , Yu Xuan- Yi  , Gao Yuan-Mei  , Huang Chun-Fu  , Xu Jing-Jun  ,   (1)北方交通大学理学院，北京  100044;南开大学物理学院，天津  300071; (2)南开大学物理学院，天津  300071
Published: December 2020

The study on the light amplification mechanism of iron-doped lithium niobate crystals has been done systematically.The experimental results indicate that the l ight amplification depends on the c-axis direction of the crystal. We propose a new view for the light amplification mechanism of the two-wave mixing in iron-do ped lithium niobate crystals: The diffusion mechanism cannot be neglected, and t he light amplification mechanism in doped lithium niobate crystals is caused by both the diffusion and the transient energy transfer. The decrease of the amplif ied light intensity after the steady-state is due to the decreases of the trans ient energy transfer with time and the energy dissipation caused by the beam fan ning.
Tight-binding molecular-dynamics study of melting behaviour of small silicon clu sters
Authors: Wang JianWang  , Shao-Qing  ,   中国科学院金属研究所沈阳材料科学国家（联合）实验室，沈阳  110016
Published: December 2020

The Tight_binding molecular_dynamics(TBMD) has been used to study the melting behaviour of small silicon clusters Sin（n=5—10）. We report the calcu lated res ults of the latent heat of fusion　Δμls and the melting temperature Tm as a function of cluster size. Δμls and Tm　exhibit a s trong dependen ce on cluster size. The melting mechanisms of silicon clusters are distinguished from metal clusters. The melting of metal clusters can be described as a tran sition from a low_energy solid_like structure at low temperatures to a higher_en ergy liquid_like structure at high temperatures. At the transition temperature, metal clusters undergo a dynamics coexistence of the two states, while the silic on clusters undergo an intermediate state which is neither liquid_like structure nor solid_like structure. The melting points obtained by using different calcul ation methods and definitions also have been compared in this work.
Theoretical study on the giant magnetoimpedance in coaxial-cable wire and sandwi ched film
Authors: Liu Jiang-Tao  , Zhou Yun-Song  , Wang Ai-Ling  , Jiang Hong-Wei  , Zheng Wu  ,   首都师范大学物理系，北京  100037
Published: December 2020

Two phenomenological models based on the experimental samples of giant magnetoimpedance (GMI) effect are proposed. The first model is a coaxial_cable wire composed of copper cylindrical wire electroplated with a soft magnetic layer, and the second is a sandwiched film structured by two soft magnetic layers, within whic h Cu or Ag serves as the central layer. Their characteristics are discussed theo retically using Maxwell equations and Landau_Lifshitz equation. It is proved tha t for the two models the origination of enhancement of GMI effect is the same, a nd the difference between them arises from the parameter of their geometry. The structure of double deck is better than a single layer for the identical magneti c materials in GMI effect. The application of the theoretical models to real mat erials is examined. Predictions by using the models are qualitatively in agreeme nt with experimental data.
Thermodynamic properties of random transverse mixed Ising spin system with cryst al field
Authors: Zhang Ya-Nan  , Yan Shi-Lei  ,   (1)苏州大学物理系，苏州  215006; (2)苏州大学物理系，苏州  215006;苏州大学薄膜材料江苏省重点实验室，苏州  215006
Published: December 2020

Making use of the effective field theory (EFT) and a cutting approximation, in the framework of Ising model, we investigate the thermodynamic properties of a random transverse mixed spin system with a crystal field. Special emphasis is placed on the influence of crystal field, transverse field and random concentration on phase transitions of the system. Our studies find that a smaller crystal field cannot change the percolation threshold of the critical transverse field in the presence of a random transverse field, and that the reentrant phenomena shall appear in the range of random concentration concerned when the transverse field takes a larger value, where as the reentrant phenomena do not occur and when the transverse field takes a smaller value. These new thermodynamic properties have not been reported in previous works so far as we know. We give a series of pha se diagrams and discuss them in detail.
Thermodynamics stability for ground state CUO
Authors: Xue Wei-Dong  , Zhu Zheng-He  ,   (1)四川大学原子分子物理研究所，成都  610065; (2)四川师范大学化学系，成都  610066
Published: December 2020

Based on the quantum mechanics, statistical thermodynamics and Debye solid theory,we have successfully calculated thermodynamic functions, energy, entropy and G ibbs functions of CUO(g),indicating that CUO(g) is stable, particularly more sta ble with rising temperature, and also providing the structural parameters of CUO (g) which are valuable for reference.
On the formula for entropy production rate
Authors: Xing Xiu-San  ,   北京理工大学物理系，北京  100081
Published: December 2020

In this paper we derive a statistical formula for entropy production rate,namely the law of entropy increase in 6N- and 6-dimensional phase spaces. The exp ression is P=kD(Δqθ)2,which means the entropy produc tion rate P eq ual to the product of diffusion coefficient D,the mean square value of the spac e gradient of the percentage departure from equilibrium θ and Boltzmann constan t k. It shows that the macroscopic entropy production in a nonequilibrium system is caused by spatially stochastic and inhomogeneous departure from equilibrium of the number density of micro-states. As its application, we use this formula t o investigate three nonequilibrium physical topics: free expansion of a gas, Bro wnian motion, and the deformation and fracture of solids. The expressions for th eir entropy production,and the first and second time rates are presented. A new physical inference that the change of micro-structure within the system during a n irreversible process is inhomogeneous has been drawn and confirmed. We also ca lculate the entropy production rate in the stationary state, derive a special fo rmula, present the actual expressions of two examples: directed atomic diffusion and molecular motor. All these theoretical results are either in agreement with experiment or reasonable in physics.
Nonlinear adaptive multi-step-prediction of chaotic time series based on points in the neighborhood
Authors: Gan Jian-Chao  , Xiao Xian-Ci  ,   (1)电子科技大学电子工程学院,成都  610054; (2)电子科技大学电子工程学院,成都  610054;电子对抗国防科技重点实验室，成都  610036
Published: December 2020

In this paper a class of nonlinear adaptive multi-step-prediction algorithm base d on the manifold theory was proposed. We have performed the multi-step-predicti on by exploiting images of P-step iterations of several nearest neighbors with t his method. The simulation indicated that this method was available and could im prove the prediction speed, and that the series of the standard deviation of err or after prediction has an exponential growth ratio that is the largest Lyapunov exponent.
Synthesis and magnetism of the intercalation compound Fe0.95PS3(MV)0.11
Authors: Dai Yao-Dong  , He Yun  , Huang Hong-Bo  , Shao Ting  , Xia Yuan-Fu  ,   (1)南京大学物理系，南京  210093; (2)南京大学物理系，南京  210093;南京航空航天大学材料科学与技术学院，南京  210016
Published: December 2020

The intercalation compound Fe0.95PS3(MV)0.11 (MV is the methylviol ogen cation) has been prepared. Its crystal structure and magnetism have been in vestigated by x-ray diffraction (XRD), susceptibility measurements and Mssbaue r experiments. Its XRD pattern can be indexed in a monoclinic unit cell with a=0 .879nm, b=0.944?nm, c=1.070nm, β=114.76°. The distance between layers of this intercalation compound is increased by 0.33nm compared with that of FePS3. Th e data of susceptibility show that second-order magnetic phase transitions have occurred when the temperature changed from 300K down to 4.2K. A ferromagnetic ph ase transition occurred below TC=84K. An antiferromagnetic phase tran sition occurred below TN=26K. The results of Mssbauer spectra taken in the t emperatur e range of 12 to 300K indicate that there are three kinds of divalent ions with their high spin states, which imply a charge transfer from guest to the Fe—S e g antibonding orbitals of the FePS3 host lattice, and some ions have been re leased from the FePS3 host lattice and then some vacancies have been formed. T he ferromagnetism originates from a canting of the spins of Fe2+, whe reas the antiferromagnetism occurred when the canting of the spins of Fe2+ have been modified at the lowest temperatures.
Study on the photofragment excitation spectrum of SO+2 in the range of 281-332nm
Authors: Wang Zhong  , Zhang Li-Min  , Wang Feng  , Li Jiang  , Yu Shu-Qin  ,   中国科学院选键化学实验室，中国科学技术大学化学物理系，合肥  230026
Published: December 2020

With the preparing of SO+2(2Ａ1( 000)) by ［3+1］ multiphoton ioniz ation of the neutral SO2 molecules at 380.85nm,the photofragment exci tation (P HOFEX) spectrum in ultraviolet (UV) (281-332nm) wavelength range has been obtain ed.The PHOFEX spectrum in the UV range was assigned essentially to the SO+2(,)←SO+2(2Ａ1) transitions.The transitions fr om 2Ａ1(000) to the bend vibration levels of SO+2() were suggested,new harmon ic bend vibrational frequency ν2=241.78±0.92cm-1 and the anharmonicity constant X22=-1.71±0.01cm-1 for SO+2() was deduced.By using th e SO+ PHOFEX spectra in UV and in visible range (562-664nm), the symm etry of ,, states of SO+2 and the predissociation mechanism of SO+2(,,) were determined,that is,(i)the symmetry of ,, states of SO+2 s hould be 2 B2，2Ｂ1，2Ａ1，( ii) around ,, states there should be two r epulsive states of symmetry α2Ａ2 and β2Ｂ2，converging to the dissociation limit of SO+(X2П)+O(3Pg),(iii)the couplings betw een 2B1 and α2A2 and betwee n 2 B2 and β2Β2,lead to the dissociation to S O+(X2П)+O(3Ｐg).
Reflection and refraction on the surface of a biaxial crystal
Authors: Shen Wei-Min  , Jin Yong-Xing  , Shao Zhong-Xing  ,   中国计量学院信息工程学院,  杭州310018
Published: December 2020

A method to solve the problems about reflection and refraction on the surface of a biaxial crystal is introduced, which can be applied to calculating refractive index, polarization direction, wave vector, Poynting vector of refracted waves for any direction of incidence and any orientation of major axes. The formulae t o calculate electric amplitude and optical power of each light beam are derived. The results of numerical calculations for a KTP crystal are given.
One-dimensional photovoltaic dark spatial solitons with fully incoherent white l ight
Authors: Lu Yi  , Liu Si-Min  , Guo Ru  , Yang Li-Sen  , Huang Chun-Fu  , Wang Da-Yun  ,   (1)内蒙古师范大学物理系,呼和浩特   010022; (2)南开大学物理学院,天津   300071; (3)天津理工学院自动化系,天津   300191
Published: December 2020

We have experimentally observed, one-dimensional photovoltaic dark spatial soli tons in LiNbO3∶Fe crystal using white light from an incandescent la mp. A blac k-like soliton and a pair of gray solitons are excited from odd and even initial conditions, respectively. The waveguides induced by them can guide both incoher ent white light and coherent light. Their multi-mode structures are clearly obse rved by a probe coherent beam. The experiments demonstrate the presence of one- dimensional white light photovoltaic dark spatial solitons and show that it is p ossible that the coherent beams are controlled and guided by fully incoherent wh ite light dark spatial solitons.
The thermal/electronic transport properties of new superconductor MgB2 and MgCNi3
Authors: Wu Bai-Mei  , Li Bo  , Yang Dong-Sheng  , Zheng Wei-Hua  , Li Shi-Yan  , Cao Lie-Zhao  , Chen Xian-Hui  ,   中国科学技术大学结构分析开放实验室,物理系,合肥  230026
Published: December 2020

The temperature dependence of thermal conductivity and electronic conductivity in superconductor MgB2, MgCNi3 and Bi2Sr2Ca0.9Ce0.1Cu2O8+y are presented. The thermal conductivity of Bi2Sr2Ca0.9Ce 0.1Cu2O8+y shows a peak under Tc observ ed in cuprates, but those of MgB 2 and MgCNi3 decrease monotonously. We calculate the elec tron thermal condu ctivity and the phonon thermal conductivity by Wiedemann-Franz law. The electron s contribute a large fraction to the thermal conductivity in normal state of MgB 2 and MgCNi3 because of the non-localigation of mutual eff ect of electrons. The analysis on electronic thermal conductivity indicates that the scattering by impurities prevails in electronic thermal resistance of both samples.
The nonlinear characteristics study of the effect of salt on denaturation transi tion of DNA
Authors: Dong Rui-Xin  , Yan Xun-Ling  , Pang Xiao-Feng  , Liu Sheng-Gang  ,   (1)电子科技大学物理电子学院,成都  610054; (2)电子科技大学物理电子学院,成都  610054;聊城大学物理科学与信息工程学院,聊城  252059; (3)聊城大学物理科学与信息工程学院,聊城  252059
Published: December 2020

The nonlinear dynamics model of DNA was studied, which is related to the salt concentration. The nonlinear dynamics equation and kink solution were obtained, the influence of salt on phase boundary and phase transition force of DNA denaturation were discussed. These results obtained by numerical calculations are in agreement with experimental data in DNA.
Lumped-mass method on calculation of elastic band gaps of one-dimensional phononic crystals
Authors: Wen Ji-Hong  , Wang Gang  , Liu Yao-Zong  , Yu Dian-Long  ,   国防科技大学三院机电工程研究所,长沙 410073
Published: December 2020

With each unit cell replaced by finite cascaded massspring oscillators, 1D pho nonic crystals (PCs) can be simplified to an infinite periodic massspring chai n. Therefore, the elastic wave band structures of the 1D PCs can be calculated w ith a straightforward approach which we call lumpedmass method (LM). For compa rison, the band structures of the same 1D PC calculated with this method and the wellknown plane wave expansion method are both presented in this paper. The r esults of the two methods are in good agreement while the computation costs of L M method are much lower than that of PWE method.
Further numerical study of a maser instability driven by an electron beam
Authors: Chen Yan-Ping  , Zhou Guo-Cheng  ,   (1)中国科学院国家天文台，北京 100012; (2)中国科学院空间科学和应用研究中心，北京 100080
Published: December 2020

Thorough numerical studies of the characters of maserinstability driven by a b eam of weak relativistic electrons are performed on the basis of the theoretical model of Chen et al due to its important applicatio n in the solar radio emission. It enriches the f undamental content of the plasma instabilities. And it is expected to be applica ble widely in the study of solar and celestial emission mechanism.
Numerical investigations of Z-pinch plasma instabilities
Authors: Duan Yao-Yong  , Guo Yong-Hui  , Wang Wen-Sheng  , Qiu Ai-Ci  ,   西北核技术研究所，西安 710024
Published: December 2020

A twodimensional,radiation magnetohydrodynamics model is applied to the simu lation of Zpinch plasma sausage instability.Different implosion mechanisms in the cases of the existence and the nonexistence of instability are analyzed,an d the effects of various initial density perturbation levels on the x-ray power and energy are investigated.Numerical results show that x-ray energy output is not susceptive to sausage instabilities in a certain extent but x-ray power ve rsus time is evidently dependent on the instabilities.In addition,this paper als o studies the effects of numerical treatment of extreme low density in Zpinch simulations on numerical results.
A fluid model for the simulation of discharges in microhollow cathode
Authors: Zhou Li-Na  , Wang Xin-Bing  ,   华中科技大学激光技术国家重点实验室，武汉 430074
Published: December 2020

A microhollow cathode discharge (MHCD) was investigated by means of a fluid mode l. A highpressure He gas discharge for a cylindrical cathode was used in the model. The distribution of the electric field, electrons, ions and electron e nerg y has been calculated. The results show that there exists a hollow cathode disch arge ef fect in the discharge process. There existed electrons with high energy, and the electric field was mainly a radial field close to the cathode in the discharge area. The influ ences of gas pressure and dimension of the cathode on discharge characteristics were also investigated. We found that reducing the dimension of the cathode can enhance the hollow cathode effect, and increasing pressure will shorten the catho de fall.
Coexistance of Cu and Ag in surface nano-structure and the new behavior of glycine adsorption on silver surfaces
Authors: Ge Si-Ping  , Zhu Xing  , Yang Wei-Sheng  ,   北京大学物理学院，人工微结构与介观物理国家重点实验室,北京 100871
Published: December 2020

Novel properties of surfaces with heteronanostructures are of considerable interest in recent years. Although glycine can only be physisorbed on pure sil ver surfaces, our recent results show that monolayersilver islands deposited o n copper surfaces, with the help from the nearby nude copper surface areas, have the ability of chemisorption of glycine. In the present study we find that, on the other way round, copper islands deposited on the Ag(111) surface can also ma ke glycine being chemisorbed on the nude silver areas, although in the latter ca se the surface of a silver bulk is involved. This result demonstrates that it is the nanocoexistance of Cu and Ag on the surface, rather than any specific str ucture of the coexistance, that gives rise to the novel chemical property of the silver surfaces. Furthermore, we also find that all deposited copper islands will gradually be covered by a monolayer of Ag atoms, even at the room temperature , and thus lose the ability of helping the silver surface to gain the novel chem ical property. This indicates that in order to take advantage of the novel prope rties of heteronanostructures, we have to consider their longterm stabilit y and very often it is possible to choose the stable ones.
Segregation and interaction of rare earth and iron elements on grain boundaries in ZA27 alloys
Authors: Liu Gui-Li  , Li Rong-De  ,   沈阳工业大学材料学院，沈阳 110023
Published: December 2020

The model of liquidphase of ZA27 cast alloy was set up in terms of the molecul ar dynamics simulation. The atomic structural models of the α phaseliquid int erf ace and the grain boundary of α phase with the coincidencesite lattice were c on structed by computer programming. The environmentsensitive embedding energy (E S E) of rare earth (or iron) atom in grain, on grain boundary and on α phaseliq uid interface was calculated by Recursion method. The bond order integrals (BOI) be tween Fe, RE atom and Al were also computed. The results show that RE and iron e lements are more stable on the α phaseliquid interface than in grain, which e xpl ains the fact of very small solid solubility of RE and iron elements in α phase , and the enrichment of RE and iron elements in the solid-liquid growth front whe n solidifying. This leads to the segregation of RE and iron atoms on the grain b oundaries and the formation of the complicated REcompounds.
EDTA-assisted hydrothermal synthesis of FeS2/NiSe2 nanocomposites and the optical and electrical properties of their thin films
Authors: Wu Rong  , Zheng Yu-Feng  , Zhang Xiao-Gang  , Sun Yan-Fei  , Xu Jin-Bao  ,   (1)新疆大学物理系材料实验室,乌鲁木齐 830046; (2)新疆大学应用化学研究所，乌鲁木齐 830046
Published: December 2020

Nonacomposites of NiSe2was successfully synthesized by EDTAassisted hydrothe rm al method, adding NiSe2 with MX2 structure as seed. X_ray diffraction pa tterns indicate that the products are single phase FeS2(pyrite) with the average grain size of about 48nm. FeS2thin films were prepared by screen_printing method and annealed at high temperature. It has been shown that they have an increased direct bandgap. With increasing amount of seed, the absorbance edges in the ultraviolet_visible range show a red shift; the resistance goes up; Hall mobility rises and the carrier c oncentration decreases. The FeS2thin film shows an n_type semiconductor chara cteristic. The mechanism of the formation of FeS2(pyrite) nanocrystalline was discussed in terms of the growth process.
Effect of microwave cavity Q-value on the threshold of instability and autooscilations
Authors: Shi Qing-Fan  , Zheng Jun-Juan  , Wang Qi  ,   (1)北京理工大学应用物理系，北京 100081; (2)盐城师范学院物理系，盐城 224002; (3)中国科学院物理研究所，北京 100080
Published: December 2020

Based on the theory developed by Safonov and Yamazaki in nonlinear radiation damping of parametrically excited spin waves (J. MMM. [STHZ]161[STBZ] (1996) 27 5), we calculate the effect of microwave cavity Q_value on the threshold of instab ility and autooscilations of microwave absorption, considering both processes of nonlinear magnon_magnon interaction and magnon_photon interaction. The resu lt is basically consistent with experimental data.
Study on the structure and transport properties of discontinuous Co/SiO2 multilayers
Authors: Ge Shi-Hui  , Liu Chun-Ming  , Kou Xiao-Ming  , Jiang Li-Xian  , Li Bin-Sheng  , Li Cheng-Xian  ,   兰州大学磁学与磁性材料教育部重点实验室,兰州 730000
Published: December 2020

In this paper, charge storage and its dynamics in positively corona char ged polytetrafluoroethylene（PTFE） film electrets have been studied. It is foun d that from room temperature to 100℃ and from about 150℃, especially from 180 ℃ to higher temperatures, slow retrapping controls the transport of detrapped c h arge; however, from about 100℃ to 150℃ the fast retrapping plays a dominant ro le. The increase of the initial surface potential will lead to a significant decay of charge density, so by means of properly controlling the charging parameter an d the heat treatment process we can get positively and negatively charged PTFE f ilm electrets with the same charge density, which not only have a similar charge storage life but also an outstanding charge storage stability. 