bluuebunny/crossref_metadata_2025 huggingface dataset:
The molecular structure and potential energy function of the ground state of BH2 molecule
Authors: Yan Shi-Ying  ,   青岛大学物理科学学院，青岛  266071
Published: December 2020

The density function (B3P86) method with relativistic effective core potential has been used to optimize the structure of the ground state of BH2,BH2+ and BH2- molecules or ions,which are angular H-B-H, whose equilibrium nuclear distance and dissociation energy respectively are RBH=RBH=0.11899nm,RHH=0.21514nm，and 7.752eV; RBH=RBH=0.12896nm,RHH=0.14223nm; RBH=RBH=0.12037nm,RHH=0.21087nm. The analytic potential energy function of the ground state of BH2(2A′) has been derived by the many-body expansion theory using the equilibrium geometry structure parameters,dissociation energy and force constants,which is successfully used for describing the equilibrium geometry of BH2(2A′).
J×B heating by non-relativistic linearly polarized laser light
Authors: Jing Guo-Liang  , Yu Wei  , Li Ying-Jun  , Zhao Shi-Hua  , Qian Lie-Jia  , Tian You-Wei  , Liu Bing-Chen  ,   (1)复旦大学，上海  200433; (2)中国科学院上海光学精密机械研究所强光光学实验室，上海  201800; (3)中国矿业大学(北京)，北京  100083
Published: December 2020

The J×B heating mechanism of plasma under the radiation of non-relativistic linearly polarized laser light is studied analytically and a self-consistent theory including the effects of two kinds of ponderomotive forces is developed. Meanwhile, the J×B heating mechanism with the density profile modification is discussed, and the relation curve of the corresponding absorption coefficient vis the laser intensity is obtained. The result shows that the absorption coefficient fabs owing to the J×B heating is about 2.8% when the laser intensity factor A0＝20.
Dispersion equation of a tape helix slow wave structure filled with plasma
Authors: Xie Hong-Quan  , Liu Pu-Kun  ,   (1)西南科技大学理学院，绵阳  621010; (2)中国科学院电子学研究所，北京  100080
Published: December 2020

A tape helix show wave structure is filled with uniform plasma.A dielectric is loaded inside the region between helix and a conducting waveguide.The system is immersed in a strong longitudinal magnetic field.By means of helix tape model and linear field theory,the field equations and the boundary conditions in plasma region and dielectric region are given.On the basis of the field analysis,the dispersion relation of the slow wave structure is derived and some discussions are given.
Study of an anomalous serrated yielding phenomenon in 3004 aluminum alloy
Authors: Peng Kai-Ping  , Chen Wen-Zhe  , Qian Kuang-Wu  ,   (1)福州大学材料科学与工程学院，福州  350002; (2)福州大学材料科学与工程学院，福州  350002；福建工程学院，福州  350004
Published: December 2020

The serrated yielding in metals and alloys is an important and interesting physical phenomenon. No. 3004 aluminum alloy has been subjected to tension test in a range of strain rates 5.56×10-5s-1—5.56×10-3s-1 and temperatures 223K—773K to investigate the ordinary rules of serrated yielding phenomenon. The micro-mechanism and physical essence of serrated yielding of the material has been studied by means of activation energy, internal friction and microstructure. The results show that the serrated yielding phenomenon is associated with the dynamic strain aging process. In the serrated yielding temperature region, an anomalous serrated yielding phenomenon was found. Within this temperature region, a critical transition temperature Tt exists. The critical plastic strain for the onset of serrations has a negative or positive temperature coefficient within the temperature region lower or higher than Tt, respectively. The former is the normal serrated yielding and the latter is called “anomalous”. It is believed that the process at the temperature region lower than Tt is controlled by the interaction between Mg solute atom atmosphere and dislocations. In the positive coefficient region, the aggregation of Mg atoms and precipitation of second phase decrease the effective amount of Mg atoms in solid solution and leads to the appearance of a positive temperature coefficient of the critical plastic strain for the onset of serrations.
Theoretical study of phase transition of 3C-SiC under high pressure
Authors: Lü Meng-Ya  , Chen Zhou-Wen  , Li Li-Xin  , Liu Ri-Ping  , Wang Wen-Kui  ,   (1)亚稳材料制备技术与科学国家重点实验室，燕山大学，秦皇岛  066004; (2)亚稳材料制备技术与科学国家重点实验室，燕山大学，秦皇岛  066004；燕山大学信息科学与工程学院，秦皇岛  066004
Published: December 2020

Based on the generalized gradient approximation, we have investigated the phase transition of 3C-SiC from ZB to NaCl structure using first-principles method, and obtained the accurate symmetry Imm2 (previously regarded as lower symmetry Cmm2 and Pmm2) of the intermediate phase. The relative activation enthalpy 0.647eV is close to the result of Catti. The obtained transition pressure 69GPa is lower than the experimental value of 100GPa which may be attributed to the hysteresis of the phase transition. Meanwhile, the energy bands for ZB- and NaCl-SiC were also calculated and discussed, the results suggest that the phase transition of 3C-SiC is accompanied by an electronic transition from semiconducting to metallic character besides the structure reconstruction, which may be useful for the accurate determination of the transition pressure.
A new small signal physical model of InP-based composite channel high electron mobility transistor
Authors: Li Xiao  , Liu Liang  , Zhang Hai-Ying  , Yin Jun-Jian  , Li Hai-Ou  , Ye Tian-Chun  , Gong Min  ,   (1)四川大学物理科学与技术学院，成都  610064; (2)四川大学物理科学与技术学院，成都  610064;中国科学院微电子研究所，北京  100029; (3)中国科学院微电子研究所，北京  100029
Published: December 2020

In view of the specific properties of InP-based composite channel High Electron Mobility Transistor(HEMT),we made a correction to the traditional single channel HEMT and promote a new small signal physical model which can be applied to composite channel HEMT.The commercial device simulation program-ISE(Integrated Systems Engineering) has been used to simulate and verify this new model. We have compared the measured and simulated Hemt's I-V and transference characteristics, The change of electric field and electric current density in InGaAs/InP composite channel when quantum effect is taken into consideration are studied, The results show that due to quantum effect in InGaAs channel,in the area under the gate and near the source where electric field is low, current flow is distributed mostly in the InGaAs channel,while in the area under the gate and near the drain where electric field is high ,current flow is distributed mostly in the InP channel.Under different gate voltages ,the current flow shows different proportions in both InGaAs and InP channel. The new model is proved to be valid.
Ferroelectric-paraelectric interface dynamics related to latent heat and its finite-size effects
Authors: Ai Shu-Tao  , Cai Yuan-Zhen  ,   (1)临沂师范学院图书馆，临沂  276005; (2)临沂师范学院物理系，凝聚态物理研究所，临沂  276005
Published: December 2020

To explain the fast motion of ferroelectric-paraelectric interface, a mechanism based on latent heat release and conduction has been introduced. Its finite-size effect shows that the velocity of interface motion increases with decreasing system thickness. The theoretical results agree with experiments.
Third-order nonlinear response of conjugated polymer coated carbon nanotubes
Authors: Yi Wen-Hui  , Xu You-Long  , Feng Wei  , Wu Hong-Cai  , Gao Chao  ,   (1)天津大学材料科学与工程学院,天津  300072; (2)西安交通大学电子与信息工程学院,西安  710049
Published: December 2020

Carbon nanotubes coated with an nonlinear optical (NLO) polymer, poly［3-hexylthiophene-2,5-diyl］-［3-methoxyl-4-hydroxyl-benzylidenequino-methane］(PHTHMOBQ/MWNTs), were synthesizedvia in-situ polymerization. The micrograph of PHTHMOBQ/MWNTs has the coaxial tubular structure, which indicated that the polymer was restricted and wrapped on the surface of carbon nanotubes while propagating during polymerization. PHTHMOBQ/MWNTs showed fluorescence quenching, which involved the inter-molecular photo-induced charge transfer process. Third-order nonlinear susceptibility χ(3) and second-order hyperpolarizability γ of PHTHMOBQ/MWNTs were measured using degenerate four wave mixing at 532nm under nanosecond pulse excitation. The two pump beams were vertically polarized and the probe beam was horizontally polarized to avoid thermal effect. The third-order NLO responses were enhanced gradually when nanotube content increased, which was attributed to inter-molecular photo-induced electron transfer between PHTHMOBQ and MWNTs.
Lie-Mei symmetry of mechanical system in phase space
Authors: Fang Jian-Hui  , Wang Peng  , Ding Ning  ,   中国石油大学(华东)物理科学与技术学院,东营  257061
Published: December 2020

In this paper, a new kind of symmetry and its conserved quantities of a mechanical system in the phase space are studied. The definition of this new symmetry, i.e., the Lie-Mei symmetry is presented, and the criterion of this new symmetry is also given. The generalized Hojman and the Mei conserved quantities of the Lie-Mei symmetry of the system are obtained. An example is given to illustrative the application of the result.
Symmetries and symmetry reductions of the coupled Burgers equation
Authors: Huang Ling  ,   宁波职业技术学院机电学院,宁波  315800
Published: December 2020

Symmetry analysis is an important method used in almost all fields of natural science. In this paper, by means of the symmetry analysis, a new model, namely the coupled Burgers equations, which can be used to describe two-layer fluids is studied in detail. The Lie point symmetries of the model are obtained. By using the symmetries, four types of symmetry reductions are found. Some special types of exact solutions such as the rational solutions, travelling soliton solutions and non-travelling soliton solutions are explicitly given by solving the reduction equations.
The relativistic bound states of Coulomb potential plus a new ring-shaped potential
Authors: Chen Chang-Yuan  , Sun Dong-Sheng  , Lu Fa-Lin  ,   盐城师范学院物理系，盐城  224002
Published: December 2020

The exact solutions of bound states of Klein-Gordon equation and Dirac equation with Coulomb potential plus a new ring-shaped potentials are studied on the assumption that the scalar potential is equal to the vector potential. The exact energy expressions and the normalized wave functions for Klein-Gordon equation are presented. The exact energy expressions and the normalized spinor wave functions for Dirac equation are given.
Algebraic structure and squeezed state solutions of the XYZ antiferromagnetic Heisenberg model in an external magnetic field
Authors: Jin Shuo  , Xie Bing-Hao  ,   (1)北京航空航天大学物理系，北京  100083; (2)北京信息工程学院，北京  100101
Published: December 2020

On the linear spin-wave frame, the XYZ antiferromagnetic Heisenberg model in an external magnetic field is proposed to have an so(3,2) algebraic structure. The energy eigenvalues and the squeezed state solutions are obtained by making use of algebraic diagonalization. Some properties of the energy eigenvalues are investigated. The connection with the model of the special two-mode harmonic oscillators is also established.
Form factors of the operators at the boundary in quantum nonlinear Schr?dinger model
Authors: Wang Yan-Shen  , Yan Xue-Wen  ,   西安交通大学应用物理系,西安  710049
Published: December 2020

For the nonlinear Schrdinger model with an integrable open boundary, the scalar products of Bethe eigenstates and form factors of operators at the boundary are calculated. The results are represented as determinants of usual functions with parameters of the model.
A new method for exploring the black hole Hawking radiation——the quantum statistical method
Authors: Zhao Ren  , Zhang Li-Chun  , Hu Shuang-Qi  ,   (1)山西大同大学物理系, 大同  037009; (2)中北大学环境与安全工程系, 太原  030051; (3)中北大学环境与安全工程系, 太原  030051；山西大同大学物理系, 大同  037009
Published: December 2020

When we take the black hole as a canonical ensemble composed of a naked black hole and the two-dimensional thermodynamic surface (horizon of the black hole), using the quantum statistical method, we derive the energy spectrum of the black hole Hawking radiation. The relation between the radiation temperature of the black hole and the entropy is obtained. This gives an insight into the process of the black hole Hawking radiation.
Statistical entropy of the black hole
Authors: Zhao Ren  , Zhang Li-Chun  , Hu Shuang-Qi  ,   (1)山西大同大学物理系，大同  037009; (2)中北大学环境与安全工程系，太原  030051; (3)中北大学环境与安全工程系，太原  030051;山西大同大学物理系，大同  037009
Published: December 2020

Using the quantum statistical method, we directly obtain the partition function of Bose field and Fermi field on the background of Schwarzschild spacetime. The integral expression is obtained. According to the latest research results, Hawking radiation process of the black hole is a tunnel effect. During the creation of tunnel effect, the energy of the black hole changes. The lower limit of integral is the location of the black hole horizon. Therefore, the leading term of the black hole entropy is a quarter of the horizon area. In our calculation, there are no cutoffs. We obtain that the energy of the black hole radiation particle is proportional to the radiation temperature. This provides an insight into the thermodynamics and quantum property of the black hole.
The study of properties of Chinese railway passenger transport network
Authors: Zhao Wei  , He Hong-Sheng  , Lin Zhong-Cai  , Yang Kong-Qing  ,   (1)集美大学理学院，厦门  361021; (2)集美大学理学院，厦门  361021;兰州大学物理系，兰州  730000; (3)兰州大学物理系，兰州  730000
Published: December 2020

Complex network is adopted to describe the Chinese railway system, and two different ways are used to construct the networks. One of ways is that the stations are viewed as “nodes” and rails are regarded as “links”, thus a railway geographic network is generated. The geographic network has approximately zero average clustering coefficient, thus this network is a tree-form network. The other way is that by viewing stations as “nodes”, an arbitrary pair of stations is considered to be connected by a “link” when at least one train stops at both stations. Thereby, a railway traffic network is generated. The traffic network has comparatively large average clustering coefficient (〈C〉=0.83) and small average path length(〈d〉=3.27), and the degrees of most nodes of the traffic one follow a scale-free degree distribution. Consequently, the traffic network is a small world network with scale-free property.
A new chaotic system and its circuit emulation
Authors: Liu Ling  , Su Yan-Chen  , Liu Chong-Xin  ,   (1)西安交通大学电气工程学院，西安  710049; (2)西南交通大学机械工程系，成都  610031
Published: December 2020

In this paper a new chaotic system is presented. Some basic dynamical properties are investigated. The oscillator circuit of a new chaotic system realized is simulated using EWB.
Synchronization control of a new piecewise chaotic system
Authors: Shan Liang  , Li Jun  , Wang Zhi-Quan  ,   南京理工大学自动化系,南京   210094
Published: December 2020

Using state observers theory, the drive and response systems are constructed, and then synchronization control of a new piecewise-linear chaotic system is achieved. The sufficient condition is deduced for synchronizing two chaotic systems with different initial values. Theoretical analysis shows that the algorithm has no special requests for the original systems, nor needs the Lyapunov functions to be solved, which makes it adequate to control piecewise chaotic systems. Satisfactory results of simulation experiments verified the validity of this algorithm. The method can quickly synchronize two systems at different initial values. This algorithm should be feasible for synchronization control of a class of piecewise chaotic systems.
A novel chaos-based pseudo-random number generator
Authors: Wang Lei  , Wang Fu-Ping  , Wang Zan-Ji  ,   清华大学电机工程与应用电子技术系，电力系统国家重点实验室，北京  100084
Published: December 2020

A novel pseudo-random number generator based on z-logistic map is proposed. The observed binary sequence of the chaotic orbit which is realized exactly under finite computing precision mostly retains the statistical characteristics and the randomness of the chaos-based information source which is defined on real domain, so the cryptographic properties of this novel chaos-based pseudo-random number generator (CPRNG) can be supported theoretically. Moreover, the period of this CPRNG is predicable and the weak keys can be excluded using a simple algorithm. This CPRNG overcomes the disadvantage of the traditional CPRNG whose existing weak keys are difficult to be excluded. Theoretical analysis and simulation results demonstrate that the cryptographic properties of the novel CPRNG are good, so it has potential application prospect in many areas including data encryption.
A novel method of target detection based on the sea clutter
Authors: Jiang Bin  , Wang Hong-Qiang  , Li Xiang  , Guo Gui-Rong  ,   国防科技大学空间电子信息技术研究所，长沙  410073
Published: December 2020

Adopting the model of fractional Brownian motion, this paper presents the method of deducing Hurst exponent based on the observed sea clutter of S-band radar. Secondly the prediction technology of chaotic time series is studied based on memory-based predictor. Furthermore, adopting the method of support vector machine classifiers of the improved radial basis kernel function, this paper proposes a novel method of target detection based on the sea clutter. Thirdly, on the basis of observed sea clutter of S-band radar, the fractal dimension and the largest Lyapunov exponent are obtained, which proves its chaos and fractal characteristic. Finally, the computer simulation is carried out and the results prove the effective detection performance and noise tolerance.
Synchronization for hyperchaotic Chen system and hyperchaotic R?ssler system with different structure
Authors: Cai Guo-Liang  , Huang Juan-Juan  ,   (1)江苏大学理学院，镇江  212003; (2)江苏大学理学院，镇江  212003;盐城师范学院数学系，盐城  224002
Published: December 2020

In this paper two different methods——active control synchronization method and adaptive synchronization method are presented to study hyperchaotic Chen system and hyperchaotic Rssler system with different structure. Two different controllers are designed for synchronizing response system and drive system. When the parameters are known in advance, active control synchronization is adopted, the method is simple without constructing Lyapunov function and the time which realizes synchronization is short, when the parameters are fully unknown, the analytical expression of synchronization controller and adaptive law of parameters is given based on Lyapunov stability theory, which makes the different systems reach to synchronization and identifies the unknown parameters. Numerical simulation shows the effectiveness and feasibility of these two methods.
Experimental study of laser collimation of Cr beam
Authors: Ma Yan  , Zhang Bao-Wu  , Zheng Chun-Lan  , Ma Shan-Shan  , Li Fo-Sheng  , Wang Zhan-Shan  , Li Tong-Bao  ,   同济大学物理系,上海  200092
Published: December 2020

Laser collimation of Cr atomic beam using a transverse Doppler cooling scheme is studied. The frequency of laser is stabilized at 5±0.26MHz below the 7S3→7PO452Cr transition. The shortest size of the laser cooling beam is computed theoretically to be 13.7mm. Accordingly a Cr beam was collimated using a transverse Doppler cooling scheme. We obtained that the transverse distribution of Cr beam is less than 1/3 of the uncooled beam.
Low-frequency collective vibrational modes of asparagine by terahertz time-domain spectroscopy
Authors: Ma Shi-Hua  , Shi Yu-Lei  , Xu Xin-Long  , Yan Wei  , Yang Yu-Ping  , Wang Li  ,   中国科学院物理研究所,北京  100080
Published: December 2020

Terahertz time-domain spectroscopy has been used to measure the spectral properties of polycrystalline asparagines at room temperature. The absorption spectra and the indexes of refraction are obtained. This result shows the sample has the spectral response in terahertz spectral range and the fact demonstrates the terahertz spectra of asparagine could be used to study the molecular structure and vibration of sample. Two absorption peaks, the broad band ranged from 1.642 to 1.758THz and the narrow one located at 2.266THz, are observed in the frequency range 0.5—2.4THz. The assignments of vibrational modes in this spectral region are made using density functional theory at the level of B3LYP/6-31+G(d,p). The theoretical results agree well with the experimental data.
General self-simulating motion mode of spherical strong shock waves in ideal gas
Authors: Bian Bao-Min  , Yang Ling  , Zhang Ping  , Ji Yun-Jing  , Li Zhen-Hua  , Ni Xiao-Wu  ,   南京理工大学信息物理与工程系，南京  210094
Published: December 2020

Adopting basic-differential equations for self-simulating motion of one-dimensional nonstable flow in ideal gas, the self-simulating characteristics of wave-rear gas in spherical strong shock wave have been analyzed in detail. Additionally, the general form of propagation formula for the spherical strong shock wave,owning self-simulating motion characteristics, is deduced out. Study indicates that the self-simulating motion mode of spherical strong shock wave need not start from a point having irregularity, and the initial shock velocity and self-simulating temperature function, generally, do not exist the problem of driving to infinite. And, Taylor’s self-simulating mode of the shock wave from point explosion is a special case of the general self-simulating mode with the assumption that the whole energy of the self-simulating motion is a definite value.
Fractal analysis of the structure of liquid In-80wt%Sn alloys
Authors: Ding Guo-Hua  , Zu Fang-Qiu  , Li Xian-Fen  , Xi Yun  , Shen Rong-Rong  ,   合肥工业大学材料科学与工程学院，合肥  230009
Published: December 2020

Based on the results of the X-ray diffraction experiment, we implement the fractal concept to study the liquid structure of In-80wt% Sn at 300℃. Partially-overlapping multirange fractals in the melt In-80wt%Sn are observed. According to the characteristic of the partially-overlapping multirange fractals, a model of multirange fractals in liquid structure is proposed and the simulated results agree with the experimental data, where the relative error is less than 1.5%. From the fractal analysis, the whole structure of liquid is clearly revealed, and the range of the transition region between the fractals is speculated to be related closely with the properties of the liquid alloys，and the changes of the transition region may disclose the changes of the liquid alloy characteristics.
Study of thermally assisted magnetic probe recording on perpendicular media
Authors: Zhang Li  , Zu Xiao-Tao  ,   电子科技大学应用物理系，成都  610054
Published: December 2020

This paper demonstrates a technique on heat-assisted magnetic probe recording. The recording medium is a CoNi/Pt multilayered film, suitable for perpendicular recording. Scanning tunneling microscopy(STM) current was introduced to heat the medium locally. Pulse voltages of 2—9V, 500ns in width and 100ns in risetime were used to write marks. Marking was achieved at bias voltages higher than the threshold value 4V in the shape of circular dots with an average size of 170nm. Below the threshold, no marks were observed. A simple model qualitatively explains the experiment.
Study of the band structure of the poly (para-phenylene) and its alkoxyl derivatives
Authors: Chen Zhi-Bin  , Huang Mei-Chun  ,   厦门大学物理系，厦门  361005
Published: December 2020

In this paper, the one-dimensional band structures of poly (para-phenylene) (PPP) and its alkoxyl derivatives are calculated by an extended Hückel method (BICON-CEDiT code). The results of the band gaps Eg of these materials are in agreement with the available experimental data. In addition, we found the band gaps of PPP's alkoxyl derivatives become wider as the carbon atoms increase in alkoxyl side chain. The calculation indicates that the heteroatom and side groups have an obvious effect on the band structure of polymer, which is also consistent with the experimental results. The results are useful for synthesizing PPP with different emitting wavelength.
Some new exact solutions of the Jacobi elliptic functions of NLS equation
Authors: Gong  Lun-Xun  ,   贵州师范大学理学院，贵阳  550001
Published: December 2020

New exact solutions in terms of the Jacobi elliptic functions are obtained for the nonlinear Schrdinger (NLS) equation by means of modified mapping method.
Turbulence synchronization and suppression by coupling in excitable media
Authors: Qian Yu  , Song Xuan-Yu  , Shi Wei  , Chen Guang-Zhi  , Xue Yu  ,   广西大学物理科学与工程技术学院,南宁  530004
Published: December 2020

The turbulence synchronization is achieved in the excitable media via the mutual coupling method, the coupling coefficient is given and the largest transverse Lyapunov exponent is calculated. Turbulence is suppressed in two ways by coupling with two systems in different states.
The resonance model and quantum area spectrum of Kerr-Newman black hole
Authors: Li Chuan-An  , Su Jiu-Qing  ,   菏泽学院物理系，菏泽  274015
Published: December 2020

Using the mass M, charge Q, angular momentum J and their corresponding πM,πQ,πJ of Kerr-Newman black hole, we obtain a six-dimensional space. We first establish the resonance model of black hole through criterion transforms. Then we make use of this model to analyze the quantum area spectrum of Kerr-Newman black hole.
Controlling the period-doubling bifurcation of logistic model
Authors: Tang Jia-Shi  , Ouyang Ke-Jian  ,   湖南大学力学与航空航天学院，长沙  410082
Published: December 2020

The bifurcation control of period-doubling bifurcation in logistic model have been studied in this paper. The bifurcation maps of logistic model are achieved and the bifurcation characteristic of the dynamical system is changed by using variable-parameter linear controllers. In order to change the parameter value of all existing bifurcation points and modify the shape of a bifurcation chain, we can design variable controllers in for practical aims. Moreover, the bifurcation map may be obtained more effectively by adequately choosing the controller gain.
Monte Carlo simulation of cluster growth on an inhomogeneous substrate
Authors: Gao Guo-Liang  , Qian Chang-Ji  , Zhong Rui  , Luo Meng-Bo  , Ye Gao-Xiang  ,   (1)温州大学物理系，温州  325027; (2)浙江大学物理系，杭州  310027
Published: December 2020

The growth of clusters on an inhomogeneous substrate is simulated by using Monte Carlo method. The inhomogeneous substrate is composed of two different kinds of regularly distributed materials A and B with different physical properties. Deposited particles have initial energy E0. It consumes energies EA and EB when a particle diffuses one step on phases A and B, respectively, and it consumes energy EAB when the particle passes through the phase boundary from A to B. In the simulation, E0 is much bigger than EA and EB, and the energy needed for the particle to pass through the phase boundary from B to A is set as EBA=0. Results show that the clusters aggregated on the inhomogeneous substrate are of fractal structure. When EAB is much bigger than EA and EB, the number, radius of gyration and fractal dimension of the cluster all vary periodically with ratio E0/EBA.
Assignment of photoelectron spectra of SiN cluster
Authors: Yuan Yong-Bo  , Liu Yu-Zhen  , Deng Kai-Ming  , Yang Jin-Long  ,   (1)南京理工大学应用物理系,南京  210094; (2)南京理工大学应用物理系,南京  210094;中国科技大学选键化学实验室,合肥  230026; (3)中国科技大学选键化学实验室,合肥  230026
Published: December 2020

The low-lying excited states of the SiN cluster are studied using the time-dependent (TD) density functional theory (DFT). The calculated results compared well with the available theoretical ones and are used to assign the features of this cluster in photoelectron spectrum. The results indicate that the ground state of negative SiN is 1Σ, and the X and the A signals in photoelectron spectroscopy correspond to 1Σ→2Σ and 1Σ→2Π, respectively. It shows that TDDFT, by and large, can be used to get good results for the excited states of the SiN cluster.
Numerical verification of the NIR features for 2D isotropic LHM
Authors: Meng Fan-Yi  , Wu Qun  , Jin Bo-Shi  , Wang Hai-Long  , Wu Jian  ,   (1)哈尔滨工业大学电子与信息技术研究院, 哈尔滨  150001; (2)哈尔滨工业大学电子与信息技术研究院, 哈尔滨  150001;电波环境特性及模化技术国家重点实验室,北京  102206
Published: December 2020

A 2-D isotropic left-handed metamaterial (LHM) in C band with broad bandwidth and low loss is designed. The size of its unit cell is much smaller and configuration of its unit cell is symmetrical compared with previous LHM. The double negative (DNG) feature and the negative index of refraction (NIR) feature are verified by numerical simulation to prove the existence of the LHM. The numerical results show that the DNG and NIR phenomenon appear simultaneously as predicted.
First-principles study of the lowest energy structures and electronic properties of NaBen (n=1—12) clusters
Authors: Ge Gui-Xian  , Jing Qun  , Yang Zhi  , Yan Yu-Li  , Lei Xue-Ling  , Zhao Wen-Jie  , Wang Qing-Lin  , Luo You-Hua  ,   (1)河南大学物理与信息光电子学院理论物理研究所,开封  475004; (2)河南大学物理与信息光电子学院理论物理研究所,开封  475004;华东理工大学理学院,上海  200237
Published: December 2020

The geometric configuration and electronic structure of NaBen (n=1—12) clusters have been studied by using density functional theory (DFT).The results show that the atomic structures of NaBen (n=1—12) clusters are significantly different from the host geometries; the nearest inter-atomic distances of Na-Be and the energy gaps (HOMO-LUMO) oscillate with increasing size. It is found that at size n=4, 6 and 9, the clusters are more stable than neighboring ones, especially the NaBe4 cluster. Also, the evolution with increasing size for the electronic properties of NaBen (n=1—12) clusters are discussed.
Design of a refractive/diffractive hybrid infrared bifocal optical system
Authors: Dong Ke-Yan  , Sun Qiang  , Li Yong-Da  , Zhang Yun-Cui  , Wang Jian  , Ge Zhen-Jie  , Sun Jin-Xia  , Liu Jian-Zhuo  ,   (1)长春理工大学研究生部，长春  130022; (2)中国科学院长春光学精密机械与物理研究所，应用光学国家重点实验室，长春  130033; (3)中国科学院长春光学精密机械与物理研究所，应用光学国家重点实验室，长春  130033;中国科学院研究生院，北京  100049
Published: December 2020

The application of diffractive surface in the bifocal optical system is investigated by taking the advantage of the negative dispersion and the arbitrary phase modulation characteristics of binary elements, an analysis on the zoom equation is made and a sample design is presented. It is shown that good imaging quality can be achieved with the implementation of only four Germanium lenses. When the focal length of the system is 80 mm and the F-number is 0.8, the longitudinal aberration is less than 72 μm, the modulation transfer function (MTF) of 10 lp/mm is greater than 0.8 ；when the focal length is 160 mm and the F-number is 1.6, the longitudinal aberration is less than 35 μm, MTF of 10 lp/mm is greater than 0.7.
Quantum entanglement of the binomial field interacting with a cascade three-level atom
Authors: Hu Yao-Hua  , Fang Mao-Fa  , Liao Xiang-Ping  , Zheng Xiao-Juan  ,   湖南师范大学物理与信息科学学院,长沙  410081
Published: December 2020

Quantum entanglement between a binomial field and a cascade three level atom is studied by using quantum entropy theory, and the influences of the initial state parameters of the field and the atom on the quantum entanglement are discussed. The results show that quantum entanglement of all states from the coherent state to number state interacting with a cascade three level atom can be displayed by using the binomial field property. Steady field-atom qutrit entanglement state can be prepared via the appropriate selection of system parameters.
Quntum interference of four-level atomic system embedded in photonic band gap structure
Authors: Fang Yuan-Feng  , Du Chun-Guang  , Li Shi-Qun  ,   清华大学物理系,量子信息与测量教育部重点实验室，北京  100084
Published: December 2020

We study the steady and transient optical properties of electromagnetically induced transparency(EIT), spontaneous emission, and the photonic switching for a four-level atomic system embedded in photonic band gap(PBG) structures. The theoretical analysis shows that a special density of modes (DOM) can induce abnormal spectrum of absorption, dispersion，spontaneous emission and transient gain without inversion, and they can be controlled by an externally applied coherent light. Furthermore, we discuss the effects of the nonsingular DOM on the EIT windows and on the photon switch in detail.
Theoretical analysis and numerical calculation of LD pumped passively Q-switched Er3+,Yb3+ co-doped phosphate glass lasers
Authors: Wu Zhao-Hui  , Song Feng  , Liu Shu-Jing  , Cai Hong  , Su Jing  , Tian Jian-Guo  , Zhang Guang-Yin  ,   南开大学光子学中心，天津  300071;弱光非线性光子学材料先进技术及制备教育部重点实验室，天津  300457
Published: December 2020

An analytical model of passively Q-switched diode-pumped Er-Yb:glass laser with a Co2+:MgAl2O4 plate as a saturable absorber has been developed. Considering energy transfer between Er3+ and Yb3+, upconversion luminescence and the transition processes of the Co2+ in the Co2+:MgAl2O4 plate, rate equations of the passively Q-switched laser are presented and useful conclusions are drawn by numerical analysis in the paper. The model is very useful for optimizing these kind of lasers.
Theoretic analysis of the cat’s eye cavity He-Ne laser
Authors: Xu Zhi-Guang  , Zhang Shu-Lian  , Li Yan  , Du Wen-Hua  ,   清华大学精密测试技术及仪器国家重点实验室，北京  100084
Published: December 2020

A concave mirror and a cat's eye reflector acting as a resonator mirror coustitute a cat's eye cavity. The parallelism of the incident and the reflected beams achieved by using three kinds of cat's eye reflectors (one ideal cat's eye reflector and two reflectors with errors), and the parameters of Gaussian beam in resonators which respectively use the three kinds of cat's eye reflectors are accurately calculated. We arive at the conclusion that for the Gaussian beam the cat's eye reflector is ideal and gives best parallelism of the incident and the reflected beam when the focal length of the convex lens, the radius of curvature of the concave mirror and the distance between them are equal. In this case the cat's eye cavity has the highest stability along with the largest fundamental mode volume and the least far-field divergence angle of fundamental mode. In the cavity design, one should strive to decrease the focal length of the convex lens in the cat's eye reflector and increase the radius of curvature of the output mirror. The influence on resonator performance when there are errors in the cat's eye reflector is also discussed. This paper gives a theoretical basis for the design of cat's eye cavity lasers.
All fiber dynamic gain equalizer based on a fiber grating with rotary refractive index change
Authors: Zhu Tao  , Rao Yun-Jiang  , Wang Ruo-Kun  , Wang Jiu-Ling  ,   (1)电子科技大学宽带光纤传输与通信系统技术教育部重点实验室，成都  610054;重庆大学光电技术及系统教育部重点实验室，重庆  400044; (2)重庆大学光电技术及系统教育部重点实验室，重庆  400044; (3)重庆大学光电技术及系统教育部重点实验室，重庆  400044;电子科技大学宽带光纤传输与通信系统技术教育部重点实验室，成都  610054
Published: December 2020

An all-fiber dynamic gain equalizer for flattening Er-doped fiber amplifiers based on a long period fiber grating (LPFG) with rotary refractive index change induced by high-frequency CO2 laser pulses is reported, for the first time to our knowledge. Experimental results show that its transverse load sensitivity is up to 0.37dB/(g·mm-1), which is 9 times higher than that of a normal LPFG induced by the same method. In addition, it is found that the strong orientation-dependence of the transverse load sensitivity of the normal LPFG reported previously has been weakened considerably. Therefore, such a dynamic gain equalizer based on the transverse load and temperature characteristics of this novel LPFG provides a much larger adjustable range and makes packaging of the gain equalizer much easier. A demonstration has been carried out to flatten an Er-doped fibre amplifier to ±0.5dB over a 32nm bandwidth.
Ultra-broad-bandwidth femtosecond-pulse generation by chirped mirrors for dispersion compensation
Authors: Tian Jin-Rong  , Han Hai-Nian  , Zhao Yan-Ying  , Wang Peng  , Zhang Wei  , Wei Zhi-Yi  ,   (1)中国科学院物理研究所光物理重点实验室，计量测试高技术联合实验室，北京  100080; (2)中国科学院物理研究所光物理重点实验室，计量测试高技术联合实验室，北京  100080;北京工业大学应用数理学院，北京  100022
Published: December 2020

Through calculation of intra-cavity dispersion of Ti:sapphire laser including air, we obtained super-continuum extending from 540 to 1030 nm using four-mirror cavity composed of proper chirped mirrors. The technique to generate an octave-spanning femtosecond pulse was further discussed.
Meshless manifold method for dynamic fracture mechanics
Authors: Li Shu-Chen  , Cheng Yu-Min  , Li Shu-Cai  ,   (1)山东大学土建与水利学院，济南  250061; (2)上海大学上海市应用数学和力学研究所，上海  200072
Published: December 2020

In the paper, the meshless manifold method (MMM) is utilized to analyze transient deformations in dynamic fracture. The MMM is based on the partition of unity method and the finite coverage approximation which provides a unified framework for solving problems involving both continuums and dis-continuums. The method can treat crack problem easily because the shape function is not affected by the discontinuity in the domain. For localization problems at the tip of the discontinuity, these shape functions are more effective than those used in other numerical methods. The method avoids the disadvantages of other meshless methods in which the tip of a discontinuous crack is not considered. In meshless manifold method, the finite coverage approximation is used to construct the shape functions that overcome influences of the interior discontinuities in the displacement. Consequently, the meshless manifold method has some advantages in solving the discontinuity problems when the discontinuities are complex. When the dynamic fracture mechanics is analyzed by the MMM, the weak formulation of the partial differential equation for elastic dynamics is derived from the method of weighted residuals (MWR). The discrete space of the domain is used for the MMM. The Newmark family of methods is used for the time integration scheme. At last, the validity and accuracy of the MMM are illustrated by two numerical examples of which the numerical results agree with the analytical solution.
ZnSe-based organic-inorganic heterostructure diodes
Authors: Jiang Yan  , Yang Sheng-Yi  , Zhang Xiu-Long  , Teng Feng  , Xu Zheng  , Hou Yan-Bing  ,   北京交通大学光电子技术研究所，发光与光信息技术教育部重点实验室，北京  100044
Published: December 2020

ZnSe-based organic-inorganic heterostructure diodes in which ZnSe layer was fabricated by electron-beam evaporation were studied. Electroluminescence from ZnSe peaking at 578nm was observed from bilayer device ITO/ZnSe(50nm)/Alq3(12nm)/Al, but it is difficult to observe any EL emission from single-layer diode ITO/ZnSe(50—120nm)/Al. Based on this, we further introduced a PVK or NPB hole-transporting layer (HTL), to make trilayer devices ITO/HTL/ZnSe/Alq3/Al to investigate the influence of ZnSe layer on the emission of the trilayer devices by varying the device structure. Our experimental data of EL emission confirm the roles played by ZnSe in these devices of transporting not only electrons but also holes, as well as acting as an emissive layer. Furthermore, a luminescence mechanism of charge carriers injection luminescence in ZnSe layer is suggested.
Critical properties of the S4 model on a special diamond-type hierarchical lattice
Authors: Yin Xun-Chang  , Yin Hui  , Kong Xiang-Mu  ,   (1)曲阜师范大学物理系，曲阜  273165; (2)曲阜师范大学物理系，曲阜  273165;安庆师范学院物理系，安庆  246011
Published: December 2020

Using the renormalization-group transformation and cumulative expansion technique, the phase transition and critical properties of the S4 model on a special diamond-type hierarchical lattice are studied, and its fixed points and critical exponents are obtained. The results show that there exists a Wilson-Fisher fixed point besides the Gaussian fixed point, and compared with the Gaussian model of the special diamond-type hierarchical lattices, the critical exponents have changed.
Magnetic properties and thermal expansion anomaly of Er2AlFe16－xMnx compounds
Authors: Hao Yan-Ming  , Zhao Miao  , Fu Bin  , Wang Lin  , Yan Da-Li  ,   天津师范大学物理系，天津  300074
Published: December 2020

The structure and magnetic properties have been investigated by means of X-ray diffraction and magnetization measurements. The Er2AlFe16-xMnx (x=1, 2, 3, 4, 6 and 8) compounds have a hexagonal Th2Ni17-type structure. The thermal expansion of Er2AlFe16-xMnx (x=1, 2, 3, and 4) compounds have been investigated by X-ray dilatometry in the temperature range 103—654K. The results show that there is a thermal expansion anomaly at low temperature and a negative thermal expansion near the Curie temperature. There exists a strong and anisotropic spontaneous magnetostriction in the magnetic state of Er2AlFe16-xMnx compounds. The spin reorientation at low temperature results in an enhancement of the spontaneous volume magnetostrictive deformation of Er2AlFe16-xMnx compounds. Magnetization measurement shows that the Curie temperature and the spontaneous magnetization at 5K of Er2AlFe16-xMnx compounds decrease rapidly with increasing x, and that the Mn substitution for Fe results in obvious change of the magnetic anisotropy.
Investigation of the photoluminescence of Eu3+ doped Sr2CeO4 phosphor
Authors: Fu Shi-Liu  , Yin Tao  , Ding Qiu-Ke  , Zhao Wei-Ren  ,   汕头大学物理系，汕头  515063
Published: December 2020

Eu3+ doped Sr2CeO4 samples were prepared by a solid-state method and the luminescent properties of the samples with and without adsorbed moisture were investigated. When the Sr2-xEuxCeO4+x/2 samples were prepared, it was found that only the excitation energy in the strong charge-transfer-state (CTS) band of Ce4+—O2- peaking at about 35700cm-1 was transferred to Eu3+ion while that in the weak CTS band of Ce4+—O2- located at about 29400cm-1 led to Ce4+—O2- charge-transfer (CT) emission. After adsorption of moisture in the Sr2-xEuxCeO4+x/2 samples, the intensity of Eu3+intra-4f6 absorption transition increased remarkably, the energy transfer took place from the two Ce4+—O2- CTS bands to Eu3+ ion. The excitation energy in the strong Ce4+—O2- CTS band was transferred to the Eu3+—O2- CTS band through radiationless process involving exchange interaction, however, the weak Ce4+—O2- CTS band caused the excitation to the Eu3+ excited levels through resonance radiationless process by a multipole interaction mechanism.
The spectral properties of partially coherent flat-topped light beams propagating in linear gain or loss media
Authors: Zhang Yan  , Wen Qiao  , Zhang Bin  ,   四川大学电子信息学院，成都  610064
Published: December 2020

Based on the flat-topped beams model proposed by Li and the propagation theory of partially coherent light, the spectrum analytical expression of partially coherent flat-topped beams propagating in the linear gain or loss media was derived and the spectral properties were studied quantitatively by numerical calculation. The variation characteristics of the on-axis spectrum in near- and far-field regions have been discussed in details. The effects of the property of the linear gain or loss media and some parameters of the light source, such as the central frequency, spectrum width and spatial coherence parameter on the spectral shift have also been discussed. It can be shown that the light source parameters have greater effects on the value of the frequency shift than on the total changing trend of the spectrum along the propagation distance, whereas the latter is determined by the beam order of flat-topped beam.
Lattice expansion of Ni nanopowders
Authors: Wei Zhi-Qiang  , Xia Tian-Dong  , Wang Jun  , Wu Zhi-Guo  , Yan Peng-Xun  ,   (1)兰州大学物理科学与技术学院，兰州  730000; (2)兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州  730050; (3)兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州  730050；兰州理工大学理学院，兰州  730050
Published: December 2020

Ni nanopowders with various grain sizes were successfully prepared by anodic arc discharging plasma method.The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and the corresponding selected-area electron diffraction (SAED) to determine the crystal structure, lattice parameter, morphology and particle size. The experiment results indicate that the samples have fcc crystal structure as the bulk materials. The lattice parameter of Ni nanopowders is always larger than the equilibrium value of the perfect single crystal lattice, so the lattice expansion has taken place. The lattice parameter and the value of the unit cell volume increase significantly with the decrease of the grain size, and the increase in lattice parameter is inversely proportional to the grain size. The lattice expansion is the result of the interfacial energy and surface tension induced mutual attraction of Ni grains, and this phenomenon can be explained according to the thermodynamic theory.
Empirical study of Chinese city airline network
Authors: Liu Hong-Kun  , Zhou Tao  ,   (1)西南交通大学经济管理学院，成都  西南交通大学经济管理学院，成都  610031; (2)中国科学技术大学近代物理系，合肥  230026
Published: December 2020

We investigate the empirical properties of Chinese city airline network, where nodes and edges denote cities and direct fights. The present network is a small-world network with short average path length and high degree of clustering, and its degree distribution follows a double power law. The degree-degree correlation of the present network is different from that of the world airport network and the North American air network: The small-degree nodes of the world airport network and the North American air network are positively correlated, whereas those of the present network don't exhibit correlation behavior. And for large-degree nodes, the average neighboring degrees approach a constant in the world airport network, while the present network shows negatively correlated behavior. Previous studies suggested the absence of hierarchical structure in geographical networks, such as the Internet, the electrical power grids, and so on. However, the present network displays an obviously hierarchical property, which provides us an evidence that the geographical ingredient may have no effect on the structural evolution of Chinese city airline network. Furthermore, by setting the number of available seats per week as the edge weight, we investigate the correlation between weight and degree, and find a power-law weight-degree correlation with exponent 1.37.
First principles study on the effects of the H2O molecules on the transport properties of a carbon wire
Authors: Zhou Yan-Hong  , Xu Ying  , Zheng Xiao-Hong  ,   (1)江西师范大学物理与通信电子学院，南昌  330022; (2)中国科学院固体物理研究所材料物理重点实验室，合肥  230031
Published: December 2020

We investigate the effects of H2O molecule environment on the transport properties of a seven-atom carbon wire coupled to two Al(100) electrodes based on a recently developed ab initio nonequilibrium Green function formalism. Our results show that the transport properties are sensitive to the variation of the number and the position of the H2O molecule on the carbon wire. Especially, the equilibrium conductance of the carbon wire with single H2O molecule exhibits an oscillatory behavior with the shift of positions of the H2O molecule. For the case of two H2O molecules, the contribution of the third eigenchannel becomes larger in some configurations. The calculated current-voltage curves show different behaviors with the variation of the positions of the H2O molecules. In certain cases, large negative differential resistance is found, but not in other cases.
Influence of Co doping on ZnO film
Authors: Yang Jing-Jing  , Fang Qing-Qing  , Wang Bao-Ming  , Wang Cui-Ping  , Zhou Jun  , Li Yan  , Liu Yan-Mei  , Lü Qing-Rong  ,   (1)安徽大学物理与材料科学学院，光电信息获取与控制教育部重点实验室，合肥  230039; (2)安徽大学物理与材料科学学院，光电信息获取与控制教育部重点实验室，合肥  230039；常州工学院理学院，常州  213022
Published: December 2020

The Co2+ ions doped ZnO diluted magnetic semiconductor films, Zn1-xCoxO, were prepared on glass substrate using PVA method. The structure of Zn1-xCoxO thin films with different x value and its photoluminescence properties were investigated. The vibrating sample magnetometer (VSM) measures the ferromagnetic properties of Zn0.88Co0.12O thin films at room temperature. We analyzed the influence of doping content on its luminescence performance, and discovered that with the doping content increasing, the blue luminescence peak shows a red shift.