bluuebunny/crossref_metadata_2025 huggingface dataset:
Image potential effect on field emission from arrays of carbon nanotubes
Authors: He Chun-Shan  , Wang Wei-Liang  , Chen Gui-Hua  , Li Zhi-Bing  ,   (1)东莞理工学院电子工程学院，东莞  523808; (2)中山大学物理科学与工程技术学院，光电材料与技术国家重点实验室，广州  510275
Published: December 2020

A multi-scale quantum chemistry method is used to study field emission from arrays of carbon nanotubes. The image potential is effectively given by the image potential of an ideal metal sphere with atomic size. When the image potential is included， the field emission current density is 6 times stronger than the results without considering the image potential.
The two-scale finite element computation for thermoelastic problem in periodic perforated domain
Authors: Feng Yong-Ping  , Cui Jun-Zhi  , Deng Ming-Xiang  ,   (1)广州大学数学与信息科学学院，广州  510006; (2)中国科学院数学与系统科学研究院，北京  100190
Published: December 2020

The problems of composite structures containing small periodic perforated configurations are often encountered in the development of composite materials. These structures often consist of material with very fine micro-structures and vary sharply within a very small periodic domain. The traditional simulation of these structures involving multi-scale is very difficult because of the requirement for a tremendous amount of computer memory and CPU running time. The two-scale formal asymptotic expansions of the increment of temperature and the displacement for the structure with small periodic perforated configuration of composite material are given. The two-scale finite element algorithm is described， and simple numerical results are evaluated by two-scale finite element computational method. The numerical results show that the basic configuration and the increment of temperature strongly affect local strains and local stresses inside basic cell. A new effective numerical method is presented for thermoelastic problem in a periodic perforated domain.
Template match algorithm based on mean vector test
Authors: Liu Su-Ping  , Hu Guang-Chun  , Hu Yong-Bo  , Hao Fan-Hua  , Chu Cheng-Sheng  , Cao Lin  ,   中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

Template match arithmetic（TMA） is vital to the template identification technology of nuclear warheads and components. This paper introduces a TMA of high-resolution gamma-ray spectral fingerprint based on mean vector test. Some trials on gamma-ray samples were conducted to check the validity of TMA. The validity of TMA was comfirmed by correctly distinguishing between samples of different intensities and components. Two pieces of advice are given on the design of template structure.
Differential invariants and group classification of variable coefficient generalized Gardner equation
Authors: Guo Mei-Yu  , Gao Jie  ,   聊城大学数学科学学院,聊城  252059
Published: December 2020

By using Lie’s invariance infinitesimal criterion, we obtain the continuous equivalence transformations of a class of nonlinear Gardner equations with variable coefficients. Starting from the equivalence algebra， we construct the differential invariants of order one and make group classification. Finally some general class of variable coefficient nonlinear Gardner equations can be mapped to constant-coefficient mKdV equation and KdV-mKdV equation. In particular, some exact solutions of the Gardner equation with variable coefficients are obtained.
Extension of selective theory for power law phenomena
Authors: Wei Wei-Feng  ,   北京交通大学电子信息工程学院，北京  100044
Published: December 2020

Power law phenomena generated by human activity can be explained by selective theory. More mechanisms are brought forward to generate power law phenomena through the extension of threshold probability. It was demonstrated that selective theory is universal in deducing the power law mechanisms. Therefore, it is significant to extend the theory for further research on the power law phenomena.
Application of random matrix theory to identification of lung cancer gene networks
Authors: Li Rong  , Yan Ping-Lan  , Chen Jian  , Li Jun  , Li Jin  , Zhang Kai-Wang  , Zhong Jian-Xin  ,   湘潭大学材料与光电物理学院，湘潭  411105
Published: December 2020

We used random matrix theory （RMT） to remove the noises in lung cancer gene expression data and used the modules approach and the hierarchical clustering approach to construct the gene networks. Comparing the results given by the two methods, we found that RMT-hierarchical clustering method gives true modules as well as the correlations between the modules. The results indicate that RMT-hierarchical clustering method is an effective new method for identifying gene networks.
A method for computing acceleration-dependent Lagrangians
Authors: Ding Guang-Tao  ,   安徽师范大学物理与电子信息学院，芜湖  241000
Published: December 2020

The problem of constructing an acceleration-dependent Lagrangian from the equations of motion is studied. A method for the computation of an acceleration-dependent Lagrangian from the self-adjoint equations is presented. Two examples are given to illustrate the application of the results.
Approximate conserved quantity of a weakly nonholonomic system
Authors: Ge Wei-Kuan  ,   湖州师范学院物理系,湖州  313000
Published: December 2020

The differential equations of motion of a weakly nonholonomic system in which there is a small parameter are established. We develope the generators of infinitesimal transformations and the gauge function via the multiple power-series expansion of the parameter and substitute them into a generalized Noether identity. The Noether theorem is used to obtain an approximate conserved quantity.
Unified symmetry of mechanico-electrical systems with nonholonomic constraints of non-Chetaev’s type
Authors: Li Yuan-Cheng  , Xia Li-Li  , Wang Xiao-Ming  ,   (1)河南教育学院物理系，郑州  450014; (2)中国石油大学（华东）物理科学与技术学院,东营  257061
Published: December 2020

The unified symmetry of mechanico-electrical systems with nonholonomic constraints of non-Chetaev’s type are studied, and the definition and the criterion of unified symmetry of mechanico-electrical systems are deduced from the Lagrange-Maxwell equations. The Noether conserved quantity, the Hojman conserved quantity and a new conserved quantity deduced from the unified symmetry are obtained. An example is given to illustrate the application of the results.
Stability of a straight Kirchhoff elastic rod under the force screws
Authors: Xue Yun  , Liu Yan-Zhu  ,   (1)上海交通大学工程力学系，上海  200030; (2)上海应用技术学院机械与自动化工程学院，上海  200235
Published: December 2020

Stability of a straight Kirchhoff elastic rod with circular cross section acted by a pair of force screws is studied. Cartesian coordinate and Cardan angle are used to express the position and attitude of a cross section of the rod. Special solution which is a straight equilibrium state of the rod is derived from Kirchhoff equation of the rod, and the linear perturbation equation on this special solution is further solved. The stability of the solution for the straight equilibrium state of the rod is discussed according to the existence of non-zero solution of integration constants at various kinds of boundary conditions of the rod, such as that with two joints ends, two fixed ends, a fixed end and a free end, or a joint end and a fixed end. The critical loads are deduced and the stable ranges are plotted. Greehill formula is extended to other cases, and Euler formula for compression rod becomes its special case.
Wave generation by the falling rock in the two-dimensional wave tank
Authors: He Hai-Lun  , Liu Yong-Jun  , Mo Jun  , Song Jin-Bao  ,   (1)海军潜艇学院，青岛  266071; (2)河海大学海岸灾害及防护教育部重点实验室，南京  210098；中国科学院海洋研究所，青岛  266071；中国科学院海洋环流与波动重点实验室，青岛  266071; (3)中国科学院海洋研究所，青岛  266071；中国科学院海洋环流与波动重点实验室，青岛  266071; (4)中国科学院海洋研究所，青岛  266071；中国科学院海洋环流与波动重点实验室，青岛  266071；中国科学院研究生院，北京  100049
Published: December 2020

Wave generation by the falling rock in the two-dimensional wave tank is experimentally and numerically studied, where the numerical model utilizes the boundary element method to solve the fully nonlinear potential flow theory. The wave profiles at different times are measured in the laboratory, which are also used to test the numerical model. Comparisons show that the experimental and numerical results are in good agreement, and the numerical model can be used to simulate the wave generation due to the submarine rock falling. Further numerical tests on the influences of the rock size, density, initial position and the falling angle on the wave elevation of the generated waves are performed, respectively. The results show that the size and density of the rock have strong effects on the maximum elevation of the generated wave, while the effects of the initial position and the falling angle of the rock are also significant. When the size or the density of the rock increases, the maximum elevation of the generated wave increases. The same effect on the generated wave would be produced if the initial position of the rock becomes closer to the surface, or the falling angle between the falling route and the vertical direction turns larger. In addition, the present numerical tests reveal that the submarine rock falling provides a new generation method for the breaking wave in the wave tank.
Effective matching solutions for classical third-order standing and short-crested waves
Authors: Huang Hu  ,   上海大学上海市应用数学和力学研究所，上海  200072
Published: December 2020

It is found that the solutions for the classical third-order standing and short-crested waves cannot satisfy the required amplitude equations, exerting a direct influence on the modern shore-crested wave theories which are related closely with the classical theories. For this reason, a set of theoretical criteria are put forward to eliminate the incompatibility between the solutions and the equations, fully ensuring the inherent harmony and correctness of the finally obtained solutions.
Controlled implementation of a nonlocal and open-target destination quantum controlled-Not （CNOT） gate using partially entangled pairs
Authors: Chen Li-Bing  , Tan Peng  , Dong Shao-Guang  , Lu Hong  ,   佛山科学技术学院光电子与物理学系，佛山  528000
Published: December 2020

We show how a nonlocal and open-target destination quantum controlled-Not （CNOT） gate can be probabilistically implemented by using partially entangled pairs of particles. We first investigate the controlled implementation of a nonlocal and three-target destination CNOT gate using three partially entangled pairs, and then generalize the scheme to the case of N-target destination. In this scheme, Alice’s local generalized measurement described by a positive operator valued measurement （POVM） plays a key role. We construct the required POVM. It is worth noting that deterministic and exact implementation of a nonlocal CNOT gate can be realized using partially entangled pairs.
Phase transition of lattice quantum chromodynamics with 2+1 flavor fermions at finite temperature and finite density
Authors: Chen He-Sheng  ,   扬州大学物理科学与技术学院，扬州  225009
Published: December 2020

Quantum chromodynamics with 2+1 flavor fermions at finite temperature and finite density was studied. Polyakov loop and chiral condensate were used to determine the dependence of the phase transition on the chemical potential and hop parameter. Finite volume scaling and Monte Carlo simulation were adopted to determine the type of phase transition. It was found that the transition between confined phase and deconfined phase varied from crossover to a first order one while the hop parameter κ1 increased from a small value to nearly the chiral limit. The phase diagram was also presented.
Hawking radiation of Schwarzschild-de Sitter black hole
Authors: Hu Shuang-Qi  , Zhang Li-Chun  , Zhao Ren  ,   (1)山西大同大学理论物理研究所  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；山西大同大学理论物理研究所  大同  037009
Published: December 2020

We extend the classical Damour-Ruffini method and discuss Hawking radiation in Schwarzschild -de Sitter black hole. Under the condition that the total energy of spacetime is conservative, considering the effect of radiation particle on the spacetime and the relevance between the black hole event horizon and cosmological horizon, we obtain the black hole radiation spectrum. The radiation spectrum is no longer a pure thermal spectrum. It is related to Bekenstein-Hawking entropy change corresponding to the black hole event horizon and cosmological horizon. The result is consistent with an underlying unitary theory.
Study on the congestion in complex network based on traffic awareness algorithm
Authors: Wang Dan  , Yu Hao  , Jing Yuan-Wei  , Jiang Nan  , Zhang Si-Ying  ,   东北大学信息科学与工程学院，沈阳  110004
Published: December 2020

We investigate the influence of complex network topological structure on the traffic delivery by the traffic awareness routing strategy. In order to characterize the efficiency of the packet delivery process, we introduce an order parameter to measure the network capacity by the critical value of phase transition from free flow to congestion. Here, we present two kinds of models, based on its degree or its betweenness that the delivery capacity of each node is proportional to. Simulation results show that, in the case of identical average degree, WS small-world network is significantly more susceptible to traffic congestion than ER random networks and BA scale-free networks in the first model, while the capacities of all kinds of networks are enhanced greatly in the second model, especially for WS small-world network. Finally, it is worth noting that which of the two models will be best suitable for handling traffic delivery depends on the structural characteristics of networks.
Model reference adaptive synchronization in integration complex dynamical networks
Authors: Luo Qun  , Gao Ya  , Qi Ya-Nan  , Wu Tong  , Xu Huan  , Li Li-Xiang  , Yang Yi-Xian  ,   北京邮电大学网络与交换技术国家重点实验室信息安全中心，网络与信息攻防技术教育部重点实验室，灾备技术国家工程实验室，北京  100876
Published: December 2020

The adaptive synchronization of integration complex networks is studied,and a network division scheme is introduced according to the nature of different links. Using the Lyapunov stability theory and the adaptive feedback control method, the principle of global synchronization of rather general weighted complex dynamical networks for identical nodes and different nodes and their corresponding controllers is given. Finally, numerical results verify the effectiveness of the proposed method.
A hyperchaotic sixth-order Chua’s circuit and its hardware implementation
Authors: Li Ya  , Zhang Zheng-Ming  , Tao Zhi-Jie  ,   电子科技大学中山学院，中山  528402
Published: December 2020

A new sixth-order hyperchaotic Chua’s circuit is presented, and the Lyapunov exponent, the dimension, and the phase diagram are computed by MATLAB. At the same time, the corresponding electronic circuit is realized,and our results are in agreement with the results of simulation, which proves that this system exists and can be realized in physics.
The influence of bus stop on the dynamics of traffic flow
Authors: Jia Bin  , Li Xin-Gang  , Jiang Rui  , Gao Zi-You  ,   (1)北京交通大学交通运输学院,城市交通复杂系统理论与技术教育部重点实验室，北京  100044; (2)中国科技大学工程科学学院，合肥  230026
Published: December 2020

The impact of bus stop on the dynamics of traffic flow is studied by a cellular automata model. Two types of bus stops, non-harbor shaped and harbor shaped, are considered. The properties of traffic flow are investigated by analyzing the fundamental diagram and the spatial-temporal diagram. The influences of bus ratio and length of bus stop are analyzed in detail. The simulation results show that the non-harbor shaped bus stop has more influence on the traffic flow, and the flux cannot be effectively increased by extending the bus stop length; the harbor shaped bus stop has less influence on the traffic flow and the flux can be improved by extending the bus stop length.
Upconversion of Er3+/Yb3+ doped lead fluosilicate microcrystalline glass
Authors: Xiao Si-Guo  , Yang Xiao-Liang  , Ding Jian-Wen  ,   (1)湘潭大学材料与光电物理学院,纳米物理与稀土发光研究所，湘潭  411105; (2)湘潭大学材料与光电物理学院,纳米物理与稀土发光研究所，湘潭  411105；湘潭大学低维材料及其应用教育部重点实验室，湘潭  411105
Published: December 2020

Transparent Er3+/Yb3+ co-doped lead fluosilicate glass ceramics is prepared, which contains nano crystalline with size of 10—12 nm. The up-conversion emission in oxyfluoride glass ceramics is notably stronger than that in its glass counterpart. The green luminescence intensity of the 2 H11/2（4S3/2）→4I15/2 transition and the red luminescence intensity of 4F9/2→4I15/2 transition in the glass ceramics are 26 and 6 times stronger than those in its glass counterpart, respectively. The ratio of the green emission intensity to the red one for the lead fluosilicate glass ceramics decreases abviously, while it is almost a constant for the lead fluosilicate glass. It is believed that the low phonon energy in nanocrystallines and the changed energy transfer properties result in the enhancement of the up-conversion emission and the variation of the up-conversion spectra.
Structure and extinction properties of Mg2Si crystal
Authors: Yu Zhi-Qiang  , Xie Quan  , Xiao Qing-Quan  , Zhao Ke-Jie  ,   贵州大学理学院，新型光电子材料与技术研究所，贵阳  550025
Published: December 2020

Based on scattering theory of high-energy x-ray, the structure and extinction properties of Mg2Si crystal have been studied. It is shown that for Mg2Si with antifluorite structure extinction only occurs if the indices of diffraction H, K and L are neither all odd nor all even, and diffraction occurs if H, K and L are either all odd or all even. It is of great significance to study the crystal with antifluorite structure in application.
Dynamical stability of the dark state in an atom-heteronuclear-trimer conversion system
Authors: Meng Shao-Ying  , Wu Wei  , Liu Bin  ,   (1)辽宁大学物理学院，沈阳  110036; (2)中国工程物理研究院北京研究生部，北京  100088; (3)中国工程物理研究院北京研究生部，北京  100088；辽宁大学物理学院，沈阳  110036
Published: December 2020

We investigate the dynamical stability of a dark state of the atom-heteronuclear-trimer conversion system in a stimulated Raman adiabatic passage process. By casting the quantum Hamiltonian into an effective classical one and analyzing the eigenvalues of the Hamiltonian-Jacobi matrix obtained by linearizing the equations of motion around the fixed point corresponding to the dark state, we analytically obtain the condition for the occurrence of the dynamical instability of the atom-trimer dark state. Taking heteronuclear atoms of 87Rb and 41K as an example, we numerically give the unstable region. We find that the dynamical instability is induced by the interparticle interactions. Moreover，the occurrence of the dynamical instability depends on not only the emergence of the real or complex eigenvalues of the Hamiltonian-Jacobi matrix but also the scanning rate of the external fields.
Low-temperature collisions of Na2 with He
Authors: Wang Yue  , Dong De-Zhi  , Li Wei-Yan  , Feng Er-Yin  , Cui Zhi-Feng  ,   (1)安徽师范大学物理与电子信息学院，芜湖  241000; (2)铜陵学院电气工程系，铜陵  244000
Published: December 2020

The close coupling calculation of rotationally inelastic collision of He with Na2 is first performed by employing a recently computed ab initio potential energy surface. The process of rovibrational energy excitation and relaxation of Na2 in collision with He has been studied in detail based on the single and double exitations coupled cluster with a noniterative perturbation treatment of triple excitations CCSD （T） potential energy surface. Our results are in good agreement with the experimental results. Our results show that: （1）The elastic cross section（Δj=0） is much larger than the inelastic cross section. （2）The largest amplitude occurs at small scattering angles. At low Δj transition, the He projectile is predominantly forward scattering. Backward scattering occurs as Δj increases. （3）For inelastic cross section, the most effective transition is that with Δj=2.（4）The fast narrow diffraction oscillations in the cross sections are the obvious characteristics for the low Δj inelastic transitions, which decreases with increasing j. （5）The elastic differential-cross-sections（DCS）provides a useful visualization of rotational rainbows at low translational energy. It is beneficial to reducing the loss in molecular cooling and trapping.
Two-dimensional polarization holographic recordings in azobenzene liquid-crystalline polymer thin films
Authors: Tian Yong  , Pan Xu  , Wang Chang-Shun  , Zhang Xiao-Qiang  , Zeng Yi  ,   上海交通大学物理系，上海  200240
Published: December 2020

Two-dimensional （2D） polarization holographic recordings were accomplished in azobenzene side-chain liquid-crystalline polymer thin films. The 2D polarization grating makes up of two orthogonal 1D polarization gratings, which were written at the same place by two orthogonally linearly polarized 532 nm beams. It is found that the diffraction efficiency of 2D grating is lower than that of 1D grating, and the 2D grating acts as the integration of its componential 1D gratings. Furthermore, we find that the polarization dependency of diffraction efficiency and the polarization conversions arise from the collaboration of linear and circular birefringence.
Compact laser diode end-pumped Nd:YAG intracavity frequency-tripled quasi-continuous 355 nm laser
Authors: Liu Huan  , Gong Ma-Li  ,   清华大学精密仪器与机械学系，光子与电子技术研究中心，北京  100084
Published: December 2020

A diode-end-pumped Nd:YVO4 intracavity frequency-tripled continuous-wave 355 nm laser has been demonstrated. The laser cavity is the simple concave-to-plane linear cavity, which is short and compact. The laser cavity length is only 70 mm. The efficient second and third-harmonic waves are generated by two lithium triborate （LBO） crystals successfully. The 355 nm laser output power is 306 mW at a pump power of 2527 W with an optical-to-optical efficiency of 012% and the corresponding beam quality is satisfactory. The instability of the output power of 274 mW is less than 53%. By using the technology of intracavity frequency conversion and choosing the proper parameters in cavity design, the miniaturization and handiness of the all-solid-state continuous-wave ultraviolet lasers with the relatively low output powers are improved greatly, which will broaden the application fields of the ultraviolet lasers.
Dispersion properties and supercontinuum generation in nanofiber
Authors: Li Lin-Li  , Feng Guo-Ying  , Yang Hao  , Zhou Guo-Rui  , Zhou Hao  , Zhu Qi-Hua  , Wang Jian-Jun  , Zhou Shou-Huan  ,   (1)四川大学电子信息学院，成都  610064; (2)四川大学电子信息学院，成都  610064；华北光电技术研究所，北京  100015; (3)中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

The dispersion properties of nanofibers was numerically simulated and caculated in details, and different dispersion properties in different diameters and materials were compared. The results show that, there are two zero dispersion wavelengths in nanofibers with silica core. With the increase of fiber diameter, the disperison curve tends to smooth and the zero dispersion wavelength also changes. When the core is silicon, it only have one zero dispersion wavelength. With the increase of diameter, its zero dispersion wavelength moves to the long-wavelength end. The generalized nonlinear Schrdinger equation is adopted to describe the evolution of ultra-short laser pulse propagating in nanofibers, and is solved by using the split-step Fourier method. The influence of dispersion on the generation of supercontinuum and the evolution of pulse profile in different dispersion regions are compared. In the normal dispersion region, the output spectral width is narrow. While in the zero dispersion region and the anomalous dispersion region, the super continuum spectrum can be obtained easily.
A novel method of chirp elimination using reconstruction equivalent chirp superstructured fiber Bragg grating
Authors: Zheng Ji-Lin  , Wang Rong  , Fang Tao  , Lu Lin  , Pu Tao  , Chen Xiang-Fei  ,   (1)南京大学微结构国家实验室，南京  210093; (2)中国人民解放军理工大学通信工程学院，光信息技术实验室，南京  210007
Published: December 2020

A novel chirp elimination and pulse compression method is firstly proposed using reconstruction equivalent chirp superstructured fiber Bragg grating（REC-SSFBG）. Based on the feasibility of REC technology for any physical realizable target response， this novel chirp elimination method is suited for any model of chirped pulse. The simulation results show that the time bandwidth product decrease from 225， 265 and 250 to 0458， 0636 and 073 for linearly chirped， Gauss chirped and Lorentz chirped pulses， respectively. The original pulsewidth is 20 ps and the chirp coefficients is -5 for all the three cases. Further experiment is performed with a fabricated REC-SSFBG to compress a chirped pulse generated from commercial software with model of gain-switched distributed feedback laser diode. The pulsewidth decreases from 25 ps to 5 ps， which agrees well with the simulation.
Imprinting and consequent Rayleigh-Taylor growth
Authors: Fang Zhi-Heng  , Wang Wei  , Jia Guo  , Dong Jia-Qin  , Xiong Jun  , Zheng Wu-Di  , Li Yong-Sheng  , Luo Ping-Qing  , Fu Si-Zu  , Gu Yuan  , Wang Shi-Ji  ,   (1)北京应用物理与计算数学研究所，北京  100094; (2)上海激光等离子体研究所，上海  201800
Published: December 2020

In direct drive inertial confinement fusion， surface perturbations seeded by imprint from laser intensity variations play an important role in Rayleigh-Taylor（RT） growth. Laser imprinting and consequent RT growth in planar CH targets driven by different pulse shapes have been investigated. The experimental results reveal that the range of density modulation induced by laser imprinting is larger when the driving laser has lower foot intensity and rises more slowly. Enhancing the pre-pulse intensity can restrain the effect of laser imprinting notablely.
Tunable filter using plasma defect in one-dimensional microwave photonic crystal
Authors: Wang Shen-Yun  , Liu Shao-Bin  ,   (1)南京航空航天大学信息科学与技术学院，南京  210016; (2)南京航空航天大学信息科学与技术学院，南京  210016；东南大学毫米波国家重点实验室，南京  210096
Published: December 2020

A tunable filter is formed when a plasma defect is introduced in the one-dimensional dielectric-air microwave photonic crystal. Plasma is a dispersive medium and its equivalent refractive index is related to the frequency of the incident electromagnatic wave and the plasma frequency， so it is feasible to shift the syntonic frequency of plasma defect by changing the plasma parameters, which behaves as a tunable filter. In the numerical simulation， the finite-difference time-domain method and the piecewise linear current density recursive convolution finite-difference time-domain method are applied to the dielectric and plasma， respectively. The results show that the filter channel of this microwave photonic crystal can be tuned in a wide band in the photonic band-gap by changing the plasma frequency.
Implosion characteristics of gas-puff Z-pinch with a single-shell nozzle
Authors: Ren Xiao-Dong  , Huang Xian-Bin  , Zhou Shao-Tong  , Zhang Si-Qun  , Li Jing  , Yang Li-Bing  , Li Ping  ,   中国工程物理研究院流体物理研究所，绵阳  621900
Published: December 2020

Single-shell gas-puff Z-pinch experiments were performed on “Yang” accelerator （peak current 500—850 kA， rise time ～85 ns）. The x-ray power and yield， the time-resolved and time-integrated images of plasma implosions were measured. Based on the corresponding diagnostics， the implosion time was defined and the implosion process was divided into four stages. the initial plasma status and the distribution of radiative intensity were studied. In addition， the implosion trajectories， load mass， radial convergence and magneto- Rayleigh-Taylor （MRT） instability were analyzed.
Material growth and characterization of terahertz quantum-cascade lasers
Authors: Chang Jun  , Li Hua  , Han Ying-Jun  , Tan Zhi-Yong  , Cao Jun-Cheng  ,   中国科学院上海微系统与信息技术研究所信息功能材料国家重点实验室，上海  200050
Published: December 2020

We realized the growth of terahertz quantum-cascade laser （THz QCL） by gas source molecular beam epitaxy （GSMBE）. Electrochemical capacitance-voltage method， Hall measurement and high-resolution x-ray diffraction were used to evaluate the crystalline quality of the THz QCL active region. Meanwhile， we used an ensemble Monte Carlo method to investigate the carrier transport characteristics in a resonant-phonon THz QCL. Level alignment and electron motion under different applied biases are discussed in detail.
Effect of high magnetic field on Te films prepared by vacuum evaporation
Authors: Zhao An-Kun  , Ren Zhong-Ming  , Ren Shu-Yang  , Cao Guang-Hui  , Ren Wei-Li  ,   上海大学材料科学与工程学院，上海  200072
Published: December 2020

Thin film of tellurium was prepared by vacuum evaporation deposition on glass, polyethylene foils and Si under high magnetic field. The results show that the difference of the substrate can strongly affect the particle size, and a magnetic flux density of 4 T can accelerate the speed of growth of Te film, increase the particle size and the intensity of （011） peak of Te films.
A novel temperature-aware distributed interconnect power model
Authors: Zhu Zhang-Ming  , Zhong Bo  , Hao Bao-Tian  , Yang Yin-Tang  ,   西安电子科技大学微电子研究所，西安  710071
Published: December 2020

Base on the lumped resistance-capacitance （RC） tree power model，a novel distributed interconnect dynamic power analytical model was proposed，which considers the effect of non-uniform temperature distribution along the interconnect. The new model overtakes the defect that the lumped model cannot represent the effect of non-uniform temperature distribution on the resistance of interconnect，and estimates the total power consumption of RC tree under a non-ideal unit step input. The proposed model is used to calculate the total power consumption of interconnect under nanometer-scale complementary metal-oxide semiconductor （CMOS） typical process. The results show that the longer the interconnected line is，the greater the effect of non-uniform temperature distribution on the power consumption is，and the dynamic power per unit length keeps constant under different processes. The proposed model can accurately calculate the dynamic power of interconnects，thus can be used to optimize design of large scale interconnect router and clock network in network-on-chip structure.
Tight binding studies on the electronic structure of graphene nanoribbons
Authors: Hu Hai-Xin  , Zhang Zhen-Hua  , Liu Xin-Hai  , Qiu Ming  , Ding Kai-He  ,   长沙理工大学物理与电子科学学院，长沙  410076
Published: December 2020

Based on the π-electron energy dispersion relation of general compound lattices derived from the tight-binding model, and assuming that the transverse confinement potential of graphene nanoribbon is a infinite hard-wall potential，we obtain the energy dispersion relation of graphene nanoribbon and the conditions that determine whether it is metallic or semi-conducting. The results presented here show that the electronic structure of graphene nanoribbon is intimately related to its geometric structure （symmetry and width），so graphene nanoribbon can be modified as metallic or semi-conducting materials only by controlling its geometric configurations，which suggests that it is highly promising to use graphene nanoribbon to develop novel nano-scale devices.
Temperature characteristics of the forward voltage of GaN based blue light emitting diodes
Authors: Li Bing-Qian  , Zheng Tong-Chang  , Xia Zheng-Hao  ,   佛山科学技术学院光电子与物理学系，佛山  528000
Published: December 2020

The temperature characteristics of the forward voltage of GaN based blue light emitting diodes are studied. We find that the temperature coefficient decreases with the increasing temperature when the temperatures is relatively high. There is an inflection point as the temperature coefficient deceases，then the temperature coefficient changes from negative to positive. If the temperature still increases at this moment，the forward voltage will increase dramatically，resulting in the failure of the light emitting diodes. This phenomenon is not obvious when the current is low. When the current increases，this phenomenon becomes more and more obvious，and the temperature of inflection point becomes lower and lower. Moreover, the forward voltage increases more quickly when the temperature is higher than the inflection point temperature. By comparing the test result of another group light emitting diodes with the same package epoxy, we find that the influence of glass transition temperature of the package epoxy can be neglected. The appearance of this phenomenon is due to the rapid increment of the equivalent series resistance，of which the main reason is the rapid deterioration of the p-type layers of the GaN based blue light emitting diode. The result shows that we can judge the quality of the GaN based blue light emitting diodes p-type layers quickly by measuring the variation of the forward voltage with temperature，which is a rapid method for the researchers and producers.
Calculation of the electronic transmission spectra of a molecular device using a simplified model
Authors: Li Qiao-Hua  , Zhang Zhen-Hua  , Liu Xin-Hai  , Qiu Ming  , Ding Kai-He  ,   长沙理工大学物理与电子科学学院，长沙  410076
Published: December 2020

Based on the structural characteristics of a molecular wire coupled to electrodes，the electronic tunneling process in a molecular device consisting of such a composite molecule under a bias is modeled by a simplified successive tunneling model with asymmetric multiple potential barriers in series. An analytical expression for the electronic transmission spectrum is obtained. Then，the relations between the transmission coefficient and various parameters，such as the width and height of the barrier，the distance between two neighboring barriers，the effective mass of electron, and the bias voltage, are calculated. It is found that when the electron energies are equal to some special values，obvious resonant tunneling occurs，and the transmission coefficient is very sensitive to the parameters mentioned above. The results presented here suggest that the transport behaviors of molecular electronic devices can be significantly modified in a controlled way, for example，by altering the constituents or/and the configurations of the composite molecule.
Effect of B-site equal-valent doping on ferroelectric properties of SrBi4Ti4O15 ceramics
Authors: Shan Dan  , Zhu Jun-Chuan  , Jin Can  , Chen Xiao-Bing  ,   (1)扬州大学物理科学与技术学院,扬州  225002; (2)扬州工业职业技术学院电子信息工程系，杨州  225002
Published: December 2020

The structures and properties of Zr and Hf-modified SrBi4Ti4O15（SBTi） ceramics were investigated. We find that the basic crystal structure is not changed after the substitution of equal-valent cations Zr4+ and Hf4+ for the Ti4+ ions at B site in SBTi. Compared with the higher-valent cation doping （V, Nb）, Zr4+ and Hf 4+ substitution can also improve the ferroelectric property of SBTi. The enhancement of remnant polarization （2Pr） by Hf4+ doping is obviously larger than that by Zr4+ doping, though these two cations have almost the same radius. This indicates that the reduced concentration of oxygen vacancy is not the only reason responsible for the improvement of the 2Pr in the B site doping, and other uncertain reasons should also be considered. The piezoelectric properties of these ceramics are investigated briefly. The tendency of piezoelectric constant changing with the doping dosage is nearly consistent with the tendency of 2Pr. Meanwhile, the dielectric properties of these ceramics are investigated, the Curie temperature of the samples varieds slightly with the doping amount, which implies that the good thermal stability of SBTi is not sacrificed.
Tunable photonic microwave generation using optically injected semiconductor laser
Authors: Niu Sheng-Xiao  , Wang Yun-Cai  , He Hu-Cheng  , Zhang Ming-Jiang  ,   太原理工大学理学院物理系，太原  030024
Published: December 2020

Optically injected semiconductor laser is applied to photonic microwave generation. The microwave is generated by the beat between the oscillation frequency of the slave laser and that of the external injection light. We find that the microwave frequency can be tuned from 61 GHz to 129 GHz by varying the injection optical power in experiment. The tunable ability in our scheme can also be achieved through adjustment of the frequency detuning. Numerical simulations indicate that the frequency of the optically generated microwave can be higher than 40 GHz by using the optical injection semiconductor laser technique.
A new p-n structure ultraviolet photodetector with p－-GaN active region
Authors: Zhou Mei  , Zhao De-Gang  ,   (1)中国科学院半导体研究所集成光电子学国家重点实验室，北京  100083; (2)中国农业大学理学院应用物理系，北京  100083
Published: December 2020

A new ultraviolet photodetector of employing p menus type GaN （p－-GaN） as the active layer is proposed. It is easy to obtain the p－-GaN layer with low carrier concentration. As a result, the depletion region can be increased and the quantum efficiency can be improved. The influence of some structure parameters on the performance of the new device is investigated. Through the simulation calculation, it is found that the quantum efficiency increases with the decrease of the barrier height between the metal electrode and the p－-GaN layer, and it is also found that the quantum efficiency can be improved by reducing the thickness of the p－-GaN layer. To fabricate the new photodetector with high performance, we should employ thin p－-GaN layer as the active layer and reduce the Schottky barrier height.
Synthesis and photoluminescence of (Co, Cu)-doped ZnO thin films
Authors: Wu Ding-Cai  , Hu Zhi-Gang  , Duan Man-Yi  , Xu Lu-Xiang  , Liu Fang-Shu  , Dong Cheng-Jun  , Wu Yan-Nan  , Ji Hong-Xuan  , Xu Ming  ,   (1)攀枝花学院材料工程系,攀枝花  617000; (2)四川师范大学物理与电子工程学院&固体物理研究所,成都  610068
Published: December 2020

Co, Cu single doped and co-doped ZnO thin films were fabricated on the glass substrate by means of sol-gel process. The influence of Co and Cu doping on the surface morphologies of ZnO films was investigated. X-ray diffraction shows that all the ZnO thin film samples are well oriented and the grain size of Cu-doped ZnO film is the largest. Strong blue double emission and weak green emission were observed in the photoluminescence spectra of all samples at room temperature and both long wavelength blue peak and green peak could be modulated by doping. The blue double peaks are caused by transition of electrons from the bottom of the conduction band to zinc vacancy or from the zinc interstitial to the top of the valence band. However, the green peak is highly relevant to the oxygen slip formed by doping.
High rate growth and electronic property of μc-Si:H
Authors: Shen Chen-Hai  , Lu Jing-Xiao  , Chen Yong-Sheng  ,   郑州大学物理工程学院，材料物理教育部重点实验室，郑州  450052
Published: December 2020

The deposition parameters of hydrogenated microcrystalline silicon （μc-Si:H） films were optimized for two factors, the siliane concentration and total flow rate, under high deposition power density and high deposition pressure by very high frequency plasma enhanced chemical vapor deposition（VHF-PECVD）.The device-grade film with activation energy of 047 eV was finally prepared at a rate of 142 nm/s when the siliane concentration was 45% and the total flow rate was 100 sccm.Meanwhile,the deposition rate of microcrystalline thin films has reached 21 nm/s under 600 Pa. We have researched the electronic property and the conductivity of thin films by use of grain boundary trapping model and statistical shift of Fermi level model respectively. Moreover, we analyzed the effect of post-oxygenation on the electronic performance of thin films.
Mechanism of surface nanocrystallization in pure nickel induced by high-current pulsed electron beam
Authors: Cheng Du-Qing  , Guan Qing-Feng  , Zhu Jian  , Qiu Dong-Hua  , Cheng Xiu-Wei  , Wang Xue-Tao  ,   江苏大学材料科学与工程学院,镇江  212013
Published: December 2020

High-current pulsed electron beam （HCPEB） technique was applied to irradiate the samples of polycrystalline pure nickel. Microstructures of the irradiated surface and sub-surface were investigated by using scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The experimental results show that the surface layer melted, and 2 μm depth remelted layer was formed on the top surface. Superfast solidification of melted layer results in the formation of nano-structure of 80 nm grain size in the remelted layer. In the sub-surface regions, the structures of dislocation walls and sub- dislocation walls in it with band shape were induced by severe plastic deformation, which become the dominant structures 5—15 μm below the irradiated surface. Those defect structures crossing with each other results in grain refinement, and nanocrystal grains about 10 nm in size were produced in the sub-surface layer.
First-principles study of NaMgH3 by fluorine anion doping for hydrogen storage
Authors: Niu Xue-Lian  , Deng Yu-Fu  , Li Xue  ,   沈阳师范大学物理科学与技术学院,沈阳  110034
Published: December 2020

The chemical hydride NaMgH3 is considered to be a promising candidate for hydrogen storage materials with its high hydrogen gravimetric and volumetric densities. The mechanism of the improved dehydrogenating properties of NaMgH3 doped by F anion was investigated using plane-wave pseudopotential （PW-PP） approach based on the density functional theory （DFT）. Computational results show that the formation enthalpy and reaction enthalpy of the hydride decrease drastically with the substitution of F for H. This results in a favorable thermodynamic modification, and facilitates the dehydrogenation reaction of the hydrides.
Analyses of degeneracy in neural system and neural code
Authors: Zhang Hong  , Liu Shu-Fang  , Qian Ming-Qi  , Tong Qin-Ye  ,   (1)浙江大学生物医学工程系,杭州  310027; (2)浙江大学生物医学工程系,杭州  310027；浙江大学生物医学工程教育部重点实验室,杭州  310027; (3)浙江大学生物医学工程系,杭州  310027；浙江大学生物医学工程教育部重点实验室,杭州  310027；浙江大学神经信息中心,杭州  310027
Published: December 2020

Edelman has proposed that there are degeneracy phenomena in neural system. However, he did not discuss the modality and function about degeneracy in neuron network. In this paper, the phenomenon of degeneracy in neuron circuit of binaural localization is studied on the basis of the ordered space, and some methods of degeneracy for the neural networks are discussed. By combing the phenomenon of degeneracy with neuron coding, we can better understand the degeneracy phenomenon. Although the results we obtained are rationalistic, the Jeffress model, which is widely accepted, is covered by this circuit. Therefore, the theory proposed in the paper also has its biological basis.
Analogue correction of errors based on seasonal climatic predictable components and numerical experiments
Authors: Zheng Zhi-Hai  , Ren Hong-Li  , Huang Jian-Ping  ,   (1)兰州大学大气科学学院,兰州  730000; (2)兰州大学大气科学学院,兰州  730000；中国气象局国家气候中心,北京  100081
Published: December 2020

Based on the idea of using historical-analogue information to predict the prediction errors of model, a new method named analogue correction of errors by predictable component （FACEPC） was developed. This method is adopted to identify the predicable components for which the prediction result is relatively not quite sensitive to the initial values. And then for predicable components, an associated scheme is chosen for historical-analogue selection and error correction. This method was further applied to experiments on operational seasonal prediction model of National Climate Center. By selecting suitable analogues and prediction schemes for different regions, the results from cross-validation indicate that the predictive skill scores of summer precipitation and circulation have got significant improvement relative to systematic error correction, which looks more obvious in ENSO episodes and over regions with more predictable components. Especially, the skill scores over China area have also been clearly improved, exhibiting its potential application perspective to operational seasonal prediction. Besides, preliminary sensitive experiments show that the FACEPC-based predictions are also obviously influenced by the analogue-selected factors and the length of historical data.
A simple method for solving nonlinear wave equations for their peaked soliton solutions and its application
Authors: Liu Yu  ,   河南电力试验研究院,郑州  450052
Published: December 2020

According to the characteristics of peaked soliton solution, the undetermined coefficient method for solving nonlinear wave equations for their peaked soliton solutions is submitted and by means of the method several kinds of peaked soliton solutions are obtained for five nonlinear wave equations： the Camassa-Holm, fifth -order KdV-like, generalized Ostrovsky, combined KdV-mKdV and Klein-Gordon equations. The solutions given in literature about Camassa-Holm equation become the special cases of the solutions in this paper. The graphs of some solutions are given through numerical simulation. The special conditions under which the wave equation will have peaked soliton solution is briefly described. The method used in this paper can also be used for solving many other nonlinear equations.
A cellular automaton model of traffic considering the dynamic evolution of velocity randomization probability
Authors: Ding Jian-Xun  , Huang Hai-Jun  , Tang Tie-Qiao  ,   (1)北京航空航天大学交通科学与工程学院，北京  100191; (2)北京航空航天大学经济管理学院，北京  100191
Published: December 2020

Few cellular automaton models of traffic have taken the relationship between the randomization probability of velocity and the specific value of current velocity into account. On the basis of Nagel-Schreckenberg model, this paper presents a modified cellular automaton model in which the randomization probability evolves with the driver’s remembering to historic experience and with the traffic condition around. Numerical simulation results show that the proposed model can reveal the influence of driver’s remembering on the traffic and generate higher average velocity and flux.
Ultra-fast pulsed digital holographic diagnosis of ejected material in femtosecond laser ablation of aluminum
Authors: Hu Hao-Feng  , Wang Xiao-Lei  , Li Zhi-Lei  , Zhang Nan  , Zhai Hong-Chen  ,   南开大学现代光学研究所，光电信息技术科学教育部重点实验室，天津  300071
Published: December 2020

The dynamic process of material ejection and plasma evolution in single 50 fs laser pulse ablation of aluminum target is investigated using pulsed digital micro-holography， and highly temporally and spatially resolved dynamic digital holograms are obtained. The secondary material ejection induced by the thermoelastic wave is observed in the holograms， and at the same time， we firstly report the phenomenon of anomalous fringe shift at large time delays that results from the effect of the ejected material towards the probe beam of 400 nm wavelength. Through digital reconstruction， the two-dimensional phase shift distribution of the probe beam is obtained. By employing inverse Abel transform， we also obtained the dynamic process of spatial and temporal evolution of refractive index and free electron density distribution of the plasma. The structure and composition of the ejected material is analyzed according to its optical properties which are obtained through experiment and calculation.
A study of RHEED pattern from the epitaxial growth of Si-Ge crystal
Authors: Zhang Chong  , Ye Hui  , Zhang Lei  , Huang-Fu You-Rui  , Liu Xu  ,   浙江大学现代光学仪器国家重点实验室,杭州  310027
Published: December 2020

The patterns of Reflection high energy electron diffraction （RHEED） from the epitaxial growth of Si-Ge crystal are interpreted basing on the kinetical diffraction theory of crystal. The transmission pattern is studied and interpreted, which relates to the rough surface after crystal growth. The RHEED patterns of polycrystalline rings and twin crystal and their evolvements are analyzed with respec to the epitaxial growth conditions.