bluuebunny/crossref_metadata_2025 huggingface dataset:
A 3 W continuous-wave 589 nm yellow laser based on the intracavity sum frequency generation in a V-shaped cavity
Authors: Geng Ai-Cong  , Bo Yong  , Bi Yong  , Sun Zhi-Pei  , Yang Xiao-Dong  , Lu Yuan-Fu  , Chen Ya-Hui  , Guo Lin  , Wang Gui-Ling  , Cui Da-Fu  , Xu Zu-Yan  ,   (1)中国科学院光电研究院,北京  100080; (2)中国科学院物理研究所，北京凝聚态物理国家实验室，北京  100080; (3)中国科学院物理研究所，北京凝聚态物理国家实验室，北京  100080;中国科学院研究生院,北京  100080
Published: December 2020

This paper reports an all-solid-state yellow laser, which is based on two Nd：YAG rods connected in series and the intracavity sum frequency generation in a KTP crystal by use of a V-shaped folding configuration, and continuous-wave 589 nm light with the output power of 3 W is obtained. In order to improve the output power of the yellow light, two means are introduced. One means is optimizing the space overlapping of two fundamental beams by optimized designing of the oscillators, and the other is optimizing the intracavity power ratio of two fundamental beams by choosing proper pump powers of the two beams.
Optimize the output performance by shortening the cavity length of the THz electromagnetic wave parametric oscillator
Authors: Zhang Xian-Bin  , Shi Wei  ,   西安理工大学应用物理系，西安  710048
Published: December 2020

We realized a 85mm short cavity Fabry-Perot optical parametric oscillator by using high performance reflection mirror, and the experimental results of the THz wave output with this 85mm short cavity parametric oscillator based on the MgO:LiNbO3 Crystal are reported. Compared with the conventional 160mm parametric oscillator, the threshold decreases by 22.3%, the peak energy output of THz wave increases by 170%, the frequency tuning range increases from 0.5—2.4THz to 0.8—3.0THz. The THz wave linewidth was measured by using a Fabry-Perot interferometer based on the metal mesh plate.
Effective AC response of nonlinear metal/dielectric granular composites
Authors: Wu Ya-Min  , Chen Guo-Qing  ,   江南大学理学院，无锡  214122
Published: December 2020

T-matrix approach is generalized to study the AC response of nonlinear metal/dielectric granular composites. We have derived general expressions for effective AC response at the fundamental frequency ω and the third harmonic 3ω and the fifth harmonic 5ω. When the components possess real dielectric response, our theoretical work reduces to the one with perturbative method. We take one step forward to perform numerical calculations on the metal/dielectric composites, and the results show that the effective third-order and fifth-order nonlinear susceptibility for fundamental and third-harmonic and fifth-harmonic frequencies can achieve large enhancement near the surface plasmon resonant frequency. Moreover, the resonant frequency exhibits a red-shift with increasing volume fraction of the nonlinear component. In addition, the effect of dimensionality on the effective nonlinear responses is studied.
Study on the control of optical limiting of pulse-shape in stimulated Brillouin scattering process
Authors: Lü Yue-Lan  , Dong Yong-Kang  , Lü Zhi-Wei  ,   (1)哈尔滨工程大学理学院，哈尔滨  150001; (2)哈尔滨工业大学光电子技术研究所，哈尔滨  150001
Published: December 2020

Based on the numerical models of stimulated Brillouin scattering(SBS) limiting, the influence of seed pulse duration, induced time and seed power on transmitted pulse shape in SBS optical limiting process is theoretically investigated. By seeding a Stokes pulse into the SBS optical limiting system, the SBS induced by this seeded Stokes pulse can reshape the transmitted limited pulse profile. By choosing suitable physical parameters, the best limited temporal profile can be obtained. The theoretical simulation shows that limited pulse shape can be controlled. When seed pulse duration is chosen as five times the length of the pump pulse duration and the delay time is just the same as the pump pulse duration, the limited pulse shape levels off, and the higher the seed power is, the lower the limited power steps. Optical limiting of pulse-shape can be controlled by introducing a seed to a stimulated Brillouin scattering cell.
Research on optical breakdown of SBS media
Authors: Hasi Wu-Li-Ji  , Lü Zhi-Wei  , Li Qiang  , Ba De-Xin  , Zhang Yi  , He Wei-Ming  ,   哈尔滨工业大学光电子技术研究所，哈尔滨  150001
Published: December 2020

The influences of the size of suspended particles in the medium and chemical structural characteristics of the medium on the threshold of the optical breakdown are researched experimentally. The experimental results show that the optical breakdown threshold first rises slowly in accord with the size of suspended particles in the medium, while later it rises sharply (when the diameters of the particles are less than 0.22μm). By purifying the medium, the optical breakdown threshold can be increased; thus the phase-conjugation fidelity, the reflectivity of the energy and the stability of SBS increase correspondingly. Generally speaking, better protection to the inner chemical bond offered by the outer atoms, and less valence electron together with higher ionization energies of the outer atoms will lead to higher optical breakdown threshold of the media.
Dependence of spectrum broadening on inner diameter of capillary restricting the filamentation in high pressure gas
Authors: Cao Shi-Ying  , Zhang Zhi-Gang  , Chai Lu  , Wang Qing-Yue  , Yang Jian-Jun  , Zhu Xiao-Nong  ,   (1)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; (2)天津大学精密仪器与光电子工程学院超快激光研究室，信息技术科学教育部重点实验室，天津  300072; (3)天津大学精密仪器与光电子工程学院超快激光研究室，信息技术科学教育部重点实验室，天津  300072;北京大学信息科学技术学院，量子信息与测量教育部重点实验室，北京  100871
Published: December 2020

Inner diameter of capillary has important effect on the spectrum broadening when used to restrict filamentation in high pressure gas. In this paper, the dependence of spectrum broadening on the inner diameter of the capillary was experimentally studied. The results showed that the spectrum broadening was mainly due to filamentation at low pulse energy (0.4mJ) and the guide effect of capillary at high pulse energy (1.3mJ). Between these pulse energy levels, the capillary with a smaller diameter can result in much better spectrum broadening.
Analytical approximate solutions for Marangoni convection boundary layer equations
Authors: Zheng Lian-Cun  , Sheng Xiao-Yan  , Zhang Xin-Xin  ,   (1)北京科技大学机械工程学院,北京  100083; (2)北京科技大学数学力学系，北京  100083
Published: December 2020

This paper presents a theoretical analysis for the flow and heat transfer induced by Marangoni convection and an efficient analytical decomposition and numerical technique is given. The approximately analytical solution may be represented in terms of a rapid convergent power series with elegantly computable terms. The results are compared with the numerical ones in references and the associated transfer behavior is analyzed.
Effect of antenna configuration on power transfer efficiency for planar inductively coupled plasmas
Authors: Di Xiao-Lian  , Xin Yu  , Ning Zhao-Yuan  ,   苏州大学物理科学与技术学院，薄膜材料江苏省重点实验室，苏州  215006
Published: December 2020

Based on a transformer model for inductively cowpled plasmas (ICPs), the dependence of power coupling efficiency on Q value, plasma electron density and effective electron-atom collision frequency is analyzed. The effect of coil configuration on power coupling efficiency is studied using four types of coils (one-turn, two-turn, three-turn and four-turn planar concentric coils) experimentally. The results indicate that the inductive discharge depends on coil inductance while the coupling efficiency varies with the Q value and discharge conditions such as pressure and input power. The coupling efficiency increases with the increase of pressure and input power, which is in accordance with the transformer model. However, the prediction given in the model that an increase in coil Q value improves power coupling efficiency is only applicable for coils with the same inductance. The study on power coupling efficiency for single multi-turn coil has been applied as an experimental reference for a large-area, high density inductive discharge source using four parallel multi-turn coils.
Observation of the rear-side coherent transition radiation generated by hot electrons
Authors: Yuan Xiao-Hui  , Li Yu-Tong  , Xu Miao-Hua  , Yu Quan-Zhi  , Wang Shou-Jun  , Zhang Jie  , Zhao Wei  , Wang Guang-Chang  , Wen Xian-Lun  , Jiao Chun-Ye  , He Ying-Ling  , Zhang Shuang-Gen  , Wang Xiang-Xian  , Huang Wen-Zhong  , Gu Yu-Qiu  ,   (1)中国工程物理研究院等离子体物理国家级重点实验室，绵阳  621900; (2)中国工程物理研究院等离子体物理国家级重点实验室，绵阳  621900;四川大学原子分子物理研究所，成都  610065; (3)中国科学院物理研究所光物理实验室，北京  100080; (4)中国科学院物理研究所光物理实验室，北京  100080;中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安  710068; (5)中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安  710068
Published: December 2020

The red-shifted second harmonic emission of the laser light is observed in the laser propagation direction on the rear side of a foil target irradiated by femtosecond laser pulses. The emission is attributed to the coherent transition radiation (CTR) when the hot electrons accelerated by the v×B heating process traverse the solid-vacuum boundary. The red shift is caused by the expansion of the critical density surface towards the vacuum side. With the increase of the prepulse energy, the peak of the CTR moves further to the long wavelength side causing the broadening of the spectrum. The measurements of the CTR provide a potential diagnosis to the movement of the critical surface in the laser-plasma interaction process.
Analysis of ion noise with beam-wave interaction in klystron by two dimensional particle simulation method
Authors: Gong Hua-Rong  , Gong Yu-Bin  , Wei Yan-Yu  , Tang Chang-Jian  , Xue Dong-Hai  , Wang Wen-Xiang  ,   (1)电子科技大学 物理电子学院,成都  610054; (2)四川大学 应用物理学院,成都  610064
Published: December 2020

Ion noise in output signal of klystrons was obtained by particle-in-cell method. The interactions between beam electron, ion, secondary electron and electromagnetic field are illustrated. The mechanism of ion noise is analyzed. It shows that phase fluctuation in output signal is caused by the change of the beam current DC velocity which is affected by the change of the amount of ions. The ion interacts with beam electron and has no equilibration state. The amount of secondary electrons is small and it has little effect on ion noise, but its behaviors reflect the process of ion noise. The amplitude fluctuation of output signal is caused by the change of beam velocity and beam radius. It is also affected by the ion behaviors.
Study on free volume change in the NiP amorphous alloy under high pressure using synchrotron radiation
Authors: Li Gong  , Sun Yi-Nan  , Gao Yun-Peng  , Zhang Xin-Yu  , Luo Cong-Ju  , Liu Ri-Ping  ,   (1)燕山大学亚稳材料科学与技术重点实验室,秦皇岛  066004; (2)中国科学院高能物理研究所,北京  100039
Published: December 2020

In situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source has been used to investigated the free volume change in Ni77P23 amorphous alloy up to 30.5 GPa at room temperature in a diamond-anvil cell. The atomic configuration information such as coordination number and atomic spacing was derived by radial distribution function via Fourier transformation. The results show that in the pressure range of 0—30.5 GPa, the structure of Ni77P23 amorphous alloy is stable. The compression behavior is investigated using in-situ high pressure measurment. The equation of state -ΔV/V0=0.08606P-3.2×10-4P2+5.7×10-6P3 is determined by fitting the experimental data according to the Bridgman equation.
The analysis of morphology evolution of KABO crystal
Authors: Zhang Xue-Hua  , Luo Hao-Su  , Zhong Wei-Zhuo  ,   中国科学院上海硅酸盐研究所,上海  201800
Published: December 2020

It was found via high temperature crystal growth in situ observation device that the morphology of KABO crystal varies with the degree of supersaturation of the crystal growth solution. The existence of ［BP3］3- and ［AlO4］5- growth units was proved by the results of high temperature Raman measurement of KABO crystal growth solution. The mechanism of KABO crystal morphology evolution was analyzed through the growth-units model of anionic coordination-polyhedra. It was found that the morphology of KABO crystal was determined simultaneously by its inner structure and the growth units. The kinds and dimensions of KABO growth units vary in solutions with different supersaturation, so accordingly, the morphology of KABO crystal changes from hexagonal to triangular morphology, and then from triangular to hexagonal dendritic morphology.
Electron-vibration approximation method for hydrogen isotope compounds TiH2,TiD2 and TiT2
Authors: Zhang Li  , Zhu Zheng-He  , Yang Ben-Fu  , Long Xing-Gui  , Luo Shun-Zhong  ,   (1)四川大学原子与分子物理研究所, 成都  610065; (2)中国工程物理研究院,绵阳  621900
Published: December 2020

The ground states of TiH2,TiD2 and TiT2 are determined as 3A2 based on atomic and molecular statics and ground theory. The energy E, heat capacity Cv and entropy S of hydrogen isotopic molecules and its titanium compounds have been calculated using density functional theory (DFT) with basis set 6-311G**. The electronic and vibrational energy and entropy of single molecules TiH2,TiD2 and TiT2 are used as the energy and entropy in their solid states approximately, which is called the electron-vibration motion approximation theory(EVMAT). The calculated results of hydrogenation (and of its isotopes) thermodymical functions ΔH0, ΔS0, ΔG0 and equilibrium pressure of metallic titanium changing with temperature are in good agreement with experimental data, which confirms EVMAT theory further.
Preparation of cubic boron nitride films by radio frequency sputtering
Authors: Tian Ling  , Ding Yi  , Chen Hao  , Liu Jun-Kai  , Deng Jin-Xiang  , He De-Yan  , Chen Guang-Hua  ,   (1)北京工业大学 教育部新型功能材料重点实验室,北京  100022; (2)兰州大学 物理科学与技术学院,兰州  730000
Published: December 2020

Cubic boron nitride (c-BN) thin films with approximate 100% cubic phase and lower compressive stress were prepared on n-Si(111) substrates by radio frequency sputtering. The infrared spectra showed that the negative substrate bias had important effect on the content of cubic phase and the compressive stress of films. In addition, a relatively higher substrate resistivity favored the c-BN formation and reduced the compressive stress.
Growth mechanism and ordered structures of iron films sputter-deposited on silicone oil surfaces
Authors: Zhang Yong-Ju  , Yu Sen-Jiang  , Ge Hong-Liang  , Wu Liang-Neng  , Cui Yu-Jian  ,   (1)台州学院物理系,临海  317000;浙江大学物理系,杭州  310027; (2)中国计量学院物理系,杭州  310018; (3)中国计量学院物理系,杭州  310018;浙江大学物理系,杭州  310027
Published: December 2020

A series of iron films has been successfully fabricated by deposition on silicone oil surfaces using the DC-magnetron sputtering method, and the growth mechanism and ordered surface morphologies have been systematically studied. It is found that the growth mechanism of the iron films is similar to that of nonmagnetic films on liquid substrates,in accordance with a two-stage growth model. Large disk-shaped patterns (disks) are observed in the continuous films and their growth behaviors are mainly related to the sputtering power, deposition time and growth duration in vacuum. The experiment indicates that the disks may result from the spontaneous, free organization and gathering of the iron atoms and atomic clusters driven by the internal stress. If the sputtering power and deposition time are comparatively large, wavy buckles with a nearly uniform wavelength of about 10 μm are observed in the continuous films, generally aligning parallel to the boundaries of the disks. Further analysis shows that the top surface of the silicone oil is modified to form a soft polymer layer during deposition. Subsequent cooling of the system creates compressive stress in the iron film, which is relieved by buckling to form the wavy structures.
The influence of contact metal in carbon nanotube transistor
Authors: Li Ping-Jian  , Zhang Wen-Jing  , Zhang Qi-Feng  , Wu Jin-Lei  ,   北京大学电子学系,北京  100871
Published: December 2020

We have fabricated p-type and n-type carbon nanotube transistors (CNTFETs) by using high and low work-function metals Pt and Al as contact electrodes， respectively. The band structures indicate that the work functions of contact metals play an important role in operation mechanism of CNTFETs. We can obtain fine-tuning of Schottky barrier heights for p- and n-channel conductions by changing the contact metals. These results can be explained by taking into account the work functions of the contact metals.
The effect of doping CsNiCl3 crystal with Mg2+ on its ground level and Zero-field splitting parameters with Jahn-Teller effect
Authors: Yin Chun-Hao  , Jiao Yang  , Song Ning  , Ru Rui-Peng  , Yang Liu  , Zhang Lei  ,   中国矿业大学理学院,徐州  221008
Published: December 2020

The completely diagonalized Hamiltonian matrices of 3d2/3d8 ion configuration in the trigonal symmetry have been established by irreducible representation method. Taken into account the influence of the spin-spin coupling interactions omitted in previous publications, the spectra and the constants of crystal structure and zero-field splitting parameters of CsNiCl3 crystal and CsNiCl3: Mg2+ crystal are calculated and the influence of the doping to the spectra, the constants of crystal structure, zero-field splitting parameters and Jahn-Teller effect are studied. The results show that doping can change the structure of crystal which brings about the changes in the spectra and zero-field splitting parameters as well as Jahn-Teller effect.
Tetrapod-like ZnO nanostructures serving as cold cathodes for flat panel displays
Authors: Lin Zhi-Xian  , Guo Tai-Liang  , Hu Li-Qin  , Yao Liang  , Wang Jing-Jing  , Yang Chun-Jian  , Zhang Yong-Ai  , Zheng Ke-Lu  ,   福州大学电子科学与应用物理系，福建  350002
Published: December 2020

We have studied the field emission properties of tetrapod-like ZnO nanostructures and the fabrication of flat panel displays. Stable field emission and full-screen lighting have been realized. It is shown by our experimental results that ZnO nanometerials are good field-emission cathode materials.
Effect of La doping on ferroelectric properties of Bi4Ti3O12 thin film
Authors: Guo Dong-Yun  , Wang Yun-Bo  , Yu Jun  , Gao Jun-Xiong  , Li Mei-Ya  ,   (1)华中科技大学电子科学与技术系，武汉  430074; (2)武汉大学物理科学与技术学院，武汉  430072; (3)武汉大学物理科学与技术学院，武汉  430072;华中科技大学电子科学与技术系，武汉  430074
Published: December 2020

The Bi4Ti3O12 and Bi3.25La0.75Ti3O12 thin films are prepared on the Pt/Ti/SiO2/Si substrate using sol-gel method. The structures Pt/Bi3.25La0.75Ti3O12/Pt and Pt/Bi4Ti3O12/Pt are fabricated. The effects of La doping on the microstructures, and ferroelectric properties of Bi4Ti3O12 films are investigated. The 2Pr with test voltage 6V for the sample annealed at 700℃ increased from 12.5 μC/cm2 to 18.6 μC/cm2, and 2Vc is still 2.8 V when the La3+ ions occupy part of Bi3+ sites. The Bi3.25La0.75Ti3O12 films showed fatigue-free behavior. The mechanism of improvement of La-doped Bi4Ti3O12 ferroelectric thin films is discussed.
The effect of O4 absorption on the measurement of atmospheric trace gases with zenith-sky scattering light observations
Authors: Chen Dan  , Zhou Bin  , Hao Nan  , Chen Li-Min  ,   复旦大学环境科学与工程系，上海  200433
Published: December 2020

During the measurement of atmospheric trace gases with zenith-sky scattering light observations, the absorption feature of O4 in the ultraviolet-visible region can affect the results. The principle, equipment and method of measurent, as well as the processes of spectra analysis and concentration retrieval are presented in detail. Experiment proves that the accuracy of NO2 and O3 retrievals can be improved when considering the profile of O4 absorption. A brief comparison between our ground-based experiment results of ozone vertical column density with that measured by TOMS is also given in the last part of article.
Obtaining and stability analysis of spherical topological vesicles with complex configurations
Authors: Zhou Xiao-Hua  , Zhang Shao-Guang  ,   陕西师范大学物理与信息技术学院，西安  710062
Published: December 2020

Through building some initial shapes which are similar to target shapes in Surface Evolver, after a long time of evolvement, we obtain the starfish vesicles with D2h and D3h symmetry, which are supported by experiment. Through tracing the eigenvalues of Hessian matrix of different shapes, we find that between the oblate and the star-fish vesicles, and between the oblate and prolate vesicles, there are two discontinuous phase transformation, and the biconcave triangular shapes and the biconcave elliptic shapes are usually unstable in the SC model.
Existence theorem and its converse of conserved quantities for the nonholonomic nonconservative systems in the event space
Authors: Qiao Yong-Fen  , Zhao Shu-Hong  , Li Ren-Jie  ,   (1)东北农业大学工程学院，哈尔滨  150030; (2)莱阳农学院基础部，莱阳  265200
Published: December 2020

A general approach to the construction of conservation laws for nonholonomic nonconservative dynamical systems in the event space was presented. Firstly, the differential equations of notion of systems are written, and the definition of integrating factors is given. Next, the necessary conditions for the existence of the conserved quantities are studied in detail. Finally, the existence theorem and its converse of conserved quantities for the nonholonomic nonconservative dynamical systems in the event space are established, and an example is given to illustrate the application of the result.
Local energy integral of Birkhoffian systems
Authors: Zheng Shi-Wang  , Jia Li-Qun  ,   (1)江南大学理学院，无锡  214122; (2)商丘师范学院物理与信息工程系，商丘  476000
Published: December 2020

The purpose of this paper is to study local energy integral for the Birkhoffian systems. The condition under which there exists the integral in the Birkhoffian systems is obtained. Two examples are given to illustrate the application of the result.
Mei symmetry, Noether symmetry and Lie symmetry of an Emden system
Authors: Gu Shu-Long  , Zhang Hong-Bin  ,   (1)巢湖学院物理系，巢湖  238000; (2)南京晓庄学院物理系，南京  210017;巢湖学院物理系，巢湖  238000
Published: December 2020

The Mei symmetry, i.e. the form invariance, of an Emden system is studied. The definition and determining equation of Mei symmetry in the Emden system are given. The relations between the Mei symmetry,the Lie symmetry and the Noether symmetry are studied, and the conserved quantities of the Emden system are obtained. An example is given to illustrate the application of the results.
Symmetry theory of the Hamilton-Tabarrok-Leech’s canonical equations in generalized classical mechanics
Authors: Qiao Yong-Fen  , Zhao Shu-Hong  , Li Ren-Jie  ,   (1)东北农业大学工程学院，哈尔滨  150030; (2)莱阳农学院基础部，莱阳  265200
Published: December 2020

Symmetry theory of the generalized Hamilton-Tabarrok-Leech’s canonical equations is presented. The differential equations of motion of systems are written. The Noether symmetry, the form invariance and the Lie symmetry of systems are studied, and the corresponding conserved quantities are found. Finally, an example is given to illustrate the application of the results.
New exact solutions for the related SchrOdinger equation and the temporal-soliton and soliton-impulse
Authors: Ma Song-Hua  , Fang Jian-Ping  ,   浙江丽水学院物理系，丽水  323000
Published: December 2020

Using an entended Riccati mapping approach, we discuss the related Schr?dinger system and obtain the new exact solutions. Based on the derived solutions, the soliton-impulse and temporal-soliton and the interaction between solitons were constructed in this paper.
Direct observation of Bose-Einstein condensation transition in 87Rb atomic gases in tightly confinement QUIC trap
Authors: Xu Zhen  , Zhou Shu-Yu  , Qu Qiu-Zhi  , Liu Hua  , Zhou Shan-Yu  , Wang Yu-Zhu  ,   中国科学院上海光学精密机械研究所，量子光学重点实验室，上海  201800
Published: December 2020

By evaporative cooling in QUIC trap, Bose-Einstein condensate (BEC) was achieved with 2×105 87Rb atoms in |F=2, mF=2〉 state. We have demonstrated the criterion of BEC transition by the variation of the axial size of the atoms in tight confinement, and observed phase transition from thermal atomic gases to Bose-Einstein condensate, and measured the shift of aspect ratio of BEC during free expansion, which compared with theoretical prediction.
Study of complex behavior in a time-delayed van der Pol’s electromagnetic system (Ⅰ)——The phenomena of bifurcations and chaos
Authors: Ma Xi-Kui  , Yang Mei  , Zou Jian-Long  , Wang Ling-Tao  ,   西安交通大学电气工程学院，西安  710049
Published: December 2020

In this paper, a simple infinite dimensional system (time-delayed van der Pol’s electromagnetic system) with rigorous solution is developed. Based on Poincaré mapping of the right-traveling voltage wave at the left end of the transmission line (x=0), the phenomena of bifurcations and chaos are investigated with the variation of system parameters E and λ. Numerical results show that there are very complex nonlinear dynamical behaviors in this time-delayed system, such as attractor co-existing, intermittent chaos, quasi border collision bifurcation to chaos and period-adding phenomena. In the meantime of studying the temporal chaotic behaviors, the spatial chaotic behaviors are preliminarily analyzed. Through depicting spatial distribution profile of the voltages, the different spatial patterns are observed in the time-delayed van der Pol’s electromagnetic system with the variation of system parameters E and λ, such as chaos, period and so on.
Study of complex behavior in a time-delayed van der Pol’s electromagnetic system (Ⅱ)——Pattern dynamics in spatiotemporal chaos
Authors: Wang Ling-Tao  , Ma Xi-Kui  , Zou Jian-Long  , Yang Mei  ,   西安交通大学电气工程学院，西安  710049
Published: December 2020

Based on a simple infinite dimensional electromagnetic system consisting of a linear lossless transmission line in combination with a nonlinear boundary condition, the local map of backward voltage wave is established by using the traveling wave theory. The numerical simulation results show rich spatiotemporal nonlinear phenomena in the voltage wave on the lossless transmission line. The pattern dynamics in spatiotemporal chaos of the voltage wave on the lossless transmission line are qualitatively analyzed by depicting space-amplitude plot and space-time diagram. A good model with solution is established to study and understand the spatiotemporal chaos.
The role of inhibitory neuron in a delayed neural network
Authors: Wang Zhan-Shan  , Zhang Hua-Guang  ,   (1)东北大学信息科学与工程学院，沈阳  110004; (2)东北大学信息科学与工程学院，沈阳  110004;沈阳理工大学信息学院，沈阳  110168
Published: December 2020

The role of inhibitory self-connection in a second order recurrent neural network with delays has been investigated. A sufficient condition is proposed to guarantee the global asymptotical stability of the equilibrium point for the delayed neural network. The results indicate that an unstable neural network without inhibitory interconnections can be asymptotically stabilized to a unique equilibrium point via embedding inhibitory self-connections with proper strengths, and the role of inhibitory self-connections will be restricted by the magnitude of transmission delays. Two simulation examples are used to show the effectiveness of the obtained result.
A new method of synchronization between two different chaotic systems
Authors: Li Shuang  , Xu Wei  , Li Rui-Hong  , Li Yu-Peng  ,   (1)西北大学计算机科学系，西安  710069; (2)西北工业大学理学院应用数学系，西安  710072; (3)西北工业大学理学院应用数学系，西安  710072；西安电子科技大学应用数学系，西安  710071
Published: December 2020

Based on Lyapunov stability theory, a new method combining feedback control and adaptive control is proposed for the synchronization between two different chaotic systems. This method can be applied to solve synchronization problems of several classes of chaotic systems, e.g., Lorenz system, Chen system, Lü system, Liu system, and R?ssler system. It offers a general way of choice for the controller, and furthermore, for some concrete systems the controller can be simplified. Numerical simulation results are presented to demonstrate the effectiveness of the proposed method.
Structural characterization and phase transition of an unknown phase of boron carbon nitride compound
Authors: Bai Suo-Zhu  , Yao Bin  , Zheng Da-Fang  , Xing Guo-Zhong  , Su Wen-Hui  ,   (1)吉林大学测试科学实验中心，长春  130023; (2)吉林大学物理学院，长春  130023; (3)吉林大学物理学院，长春  130023;内蒙古民族大学化学学院,通辽  028043; (4)吉林大学物理学院，长春  130023;中国科学院长春光学精密机械与物理研究所激发态重点实验室,长春  130033
Published: December 2020

Amorphous BCN was prepared by ball milling the mixture of graphite and hexagonal BN for 120h, and then annealed for 45 min. at 1600K under 4.5GPa. The XRD，TEM and Raman scattering measurement indicated that the as-prepared sample consists of hexagonal phase Ⅰ with lattice constants a1=0.2551nm and c1=0.6716nm and hexagonal phase Ⅱ with lattice constants a2=1.2360nm and c2=0.8570nm, of which the hexagonal phase Ⅱ is an unknown phase of boron carbon nitride. Three characteristic Raman peaks located at 1279, 1368 and 1398cm-1 respectively, were observed in the Raman spectra recorded at room temperature. The temperature dependent Raman scattering spectra of the sample were taken at temperature ranging from 93 to 673K.The measuring results indicate that the hexagonal phase of Ⅰ mainly exist in the sample at 93K and hexagonal phase of Ⅰ convert to hexagonal phase of Ⅱ completely when at above 473K.The phase transition from the hexagonal phase of Ⅰ to Ⅱ occurs with increasing temperature, vice versa. The mechanism of the phase transition is discussed in the present work.
A controllable longitudinal double-well optical dipole trap for cold atoms (or cold molecules)
Authors: Mu Ren-Wang  , Ji Xian-Ming  , Yin Jian-Ping  ,   (1)华东师范大学物理系，光谱学与波谱学教育部重点实验室，上海  200062; (2)南通大学理学院，南通  226007; (3)南通大学理学院，南通  226007；华东师范大学物理系，光谱学与波谱学教育部重点实验室，上海  200062
Published: December 2020

In this paper, we propose a novel scheme to produce a longitudinal controllable double-well optical dipole trap for cold atoms (or cold molecules), which is composed of a binary π-phase plate and a lens. The π-phase plate consists of two homocentric rings with equal area and opposite phase (0 and π), and its central region is opaque. When a plane light wave passes through the above optical system, a double-well optical trap will be formed at two sides of the focal point along the optical axis. The outer radius of the binary π-phase plate can be controlled by adjusting the radius of a diaphragm, so that a double-well optical trap will evolve and finally combined into a single-well, or vice versa. We briefly introduce the basic principle and derive several optimal parameters of the trap, and show the dependence of the optical parameters (including intensity distributions) on the geometrical parameters of the system. Our study shows that the proposed controllable optical trap can be used not only to trap cold atoms (or cold molecules) and realize all-optical, double-well or two species Bose-Einstein condensation (BEC), but also to study the trapped-atom (-molecule) interference, or form a 2D array of double-layer optical traps for cold atoms (or molecules), even to prepare a novel 2D optical lattice, and so on.
The electron exchange of MeV hydrogen micro-cluster ions with solids
Authors: Yang Chao-Wen  , Miao Jing-Wei  , Wang Guang-Lin  , Liu Xiao-Dong  , Shi Mian-Gong  ,   (1)江汉大学物理与信息工程学院，武汉  430056; (2)四川大学物理科学与技术学院，教育部辐射物理及技术重点实验室，成都  610064
Published: December 2020

The products of fast ions H+, H+2 and H+3 with the energy of 0.6 to 1.8MeV passing through carbon films were measured. The yields of neutral atom H and negative ion H- for H+ at energies of 0.6,0.9,1.2,1.6 and 1.8MeV were obtained, respectively. The fitted yield curves as function of velocity of projectile agreed with experimental results very well. The transmission of H+2, H+3 at energies 1.2MeV and 1.8MeV through carbon film were also measured. The fitted transmission curves as function of dwell time of H+2, H+3 in carbon film were also obtained. Theoretical analysis and discussion on the electron loss and capture possibility in solids were made.
Theoretical study on the influence of the overlay on the pressure of laser shock wave in photomechanics
Authors: Gu Yong-Yu  , Zhang Yong-Kang  , Zhang Xing-Quan  , Shi Jian-Guo  ,   (1)江苏大学机械工程学院，镇江  212013; (2)江苏大学机械工程学院，镇江  212013；华东理工大学机械与动力工程学院，镇江  200237
Published: December 2020

The interaction between laser and material can induce strong shock wave, so a new subject of science and manufacture technology—photomechanics is being founded on the basis of the mechanical effect of laser induced shock wave which is applied in areas such as laser shock shaping and laser spallation measurement. One of the key problems is to enhance the pressure peak value of shock wave effectively, for which the overlay is generally introduced in laser shock processing to improve the shock effect. So it has important theoretical significance and application value to study the influence of overlays exerting on the shock wave pressure. With respect to rigid overlays, flexible overlays and fluid overlays respectively, we analyze the influence from the aspects of the state of surface of discontinuity of laser induced shock wave, the diffusion of gasified material and plasma and the reflection of shock wave. It is found that overlays do not raise the pressure peak value directly when the pulse width is shorter than the time for the shock wave to cross the gasified material. On the contrary, shot of laser pulse with width longer than the time of shock wave crossing the gasified material heightens the shock effects by heightening the pressure by way of restricting the diffusion of gasified material and plasma and prolonging the acting time of useful pressure through multiple reflection of the shock wave betiseen the surfaces of the workpiece and the overlay. The rigid overlay can raise the pressure peak value of shock wave greatly. But the advantage of the flexible and fluid overlays is the adaptation to the form of the surface of non-planar workpieces.
Influence of laser incidence angle on hot electrons generated in the interaction of ultrashort intense laser pulses with foil target
Authors: Yuan Xiao-Hui  , Li Yu-Tong  , Xu Miao-Hua  , Zheng Zhi-Yuan  , Liang Wen-Xi  , Yu Quan-Zhi  , Zhang Yi  , Wang Zhao-Hua  , Ling Wei-Jun  , Wei Zhi-Yi  , Zhao Wei  , Zhang Jie  ,   (1)中国科学院物理研究所光物理重点实验室，北京  100080; (2)中国科学院物理研究所光物理重点实验室，北京  100080；中国科学院西安光机所瞬态光学与光子技术国家重点实验室，西安  710068; (3)中国科学院西安光机所瞬态光学与光子技术国家重点实验室，西安  710068
Published: December 2020

The effect of laser incidence angle on the angular distribution of hot electrons generated in the interaction of an ultrashort intense laser pulse with the foil target are investigated. A new emission peaked in the target surface direction is observed for the first time. With the increase of the incidence angle, the ratio of the number of surface electrons to the total electron number increases, while the number of transmitted electron through the target decreases. It is believed that the surface hot electrons are caused by the confinement of the quasi-static surface magnetic field and electric field.
Fast electrons generated from Al targets irradiated by polarized laser pulses
Authors: Li Kun  , Li Yu-Tong  , Zhang Jun  , Yuan Xiao-Hui  , Xu Miao-Hua  , Wang Zhao-Hua  , Zhang Jie  ,   中国科学院物理研究所光物理重点实验室，北京  100080
Published: December 2020

Energy spectrum and angular distribution of fast electrons are measured in the interaction of linearly (P and S) and circularly polarized femtosecond laser pulses with an aluminum target. It is interesting to note that the angular distribution of backward going electrons is unique for S and circular polarization. For S polarization, the angular distribution of fast electrons can be explained by taking account of the surface magnetic field qualitatively.
Study on W wire array Z pinch plasma radiation at Qiangguang-Ⅰ facility
Authors: Qiu Ai-Ci  , Kuai Bin  , Zeng Zheng-Zhong  , Wang Wen-Sheng  , Qiu Meng-Tong  , Wang Liang-Ping  , Cong Pei-Tian  , Lü Min  ,   (1)西安交通大学电气工程学院，西安  710049；西北核技术研究所，西安69信箱10分箱  710024; (2)西北核技术研究所，西安69信箱10分箱  710024
Published: December 2020

Experimental study on plasma radiation characteristics of W wire array Z pinch with different initial parameters performed on Qiangguang-Ⅰ pulsed power generator of 1.4—2.1MA current with 80—100ns rise time is reported. The generator configuration and the diagnostic system for the experiments are briefly described. The total X-ray energy and peak power have been measured, and the maximum of X-ray energy and peak power are 34kJ and 1.28TW，respectively. In additional, the main results and conclusions are discussed also.
Framing shadowgraphy of 266nm laser probing for the diagnosis of Z-pinch plasmas
Authors: Wang Zhen  , Yang Jian-Lun  , Xu Rong-Kun  , Li Lin-Bo  , Xu Ze-Ping  , Zhang Fa-Qiang  , Zhong Yao-Hua  ,   (1)核物理与化学研究所，绵阳  621900; (2)清华大学工程物理系,北京  100084；核物理与化学研究所，绵阳  621900
Published: December 2020

Framing shadowgraphy of UV laser probing with the 4th harmonic Nd-YAG Laser was developed for the diagnosis of Z-pinch plasmas. This system can effectively shield visible light and has advantages of high temporal resolution, large optical angular aperture and wide measuring range. The designed parameters and experimental results in implosions of tungsten wire array are presented in this paper.
Cherenkov radiation of relativistic electron beam in the ion-channel
Authors: Wang Bin  , Tang Chang-Jian  , Liu Pu-Kun  ,   (1)四川大学物理科学与技术学院, 成都  610065; (2)中国科学院电子学研究所,北京  100800
Published: December 2020

The problem that Cherenkov radiation may exist in the ion-channel when a relativistic electron beam (REB) is injected into plasma has been demonstrated and studied. The effect of the beam-wave interaction in ion background is analyzed by use of the linear perturbation theory. The dispersion equation and the simultaneous radiation condition of the system are derived. It is clearly shown that the electromagnetic instability of the system results from the coupling of the TM mode in ion-channel to the beam mode via the electron beam. Ion beam focusing is the microscopic mechanism. The ion-beam system in the moving plasma state is analyzed rigorously in theory. Then, the frequency shift of the radiation wave and the wave growth rate in ion-channel are presented. Finally, the effects of the parameters of the system on them are discussed by numerical calculation.
Effect of H2 on polycrystalline Si films deposited by plasma-enhanced CVD using Ar-diluted SiH4
Authors: Qi Jing  , Jin Jing  , Hu Hai-Long  , Gao Ping-Qi  , Yuan Bao-He  , He De-Yan  ,   兰州大学物理系，兰州  730000
Published: December 2020

Low-temperature polycrystalline Si films were fabricated by radio frequency plasma-enhanced chemical vapor deposition using SiH4, Ar and H2 as source gas. It was found that the content of H2 in the mixture plays an important role for crystallization of Si films. High-quality low-temperature polycrystalline Si films were obtained under the optimal amount of H2 in the source gas.
Elastic behaviour of Nd60Al10Fe20Co10 bulk metallic glass under pressure
Authors: Zhang Zhi  , Chen Chun-Ling  , Wang Zhao-Long  , Yu Dong-Man  ,   河南理工大学材料科学与工程学院，焦作  454003
Published: December 2020

Measurements were carried out under hydrostatic pressure up to 0.5GPa at room temperature, by using an ultrasonic pulse-echo method to measure the transit time of longitudinal and transverse elastic waves (10MHz) in a Nd60Al10Fe20Co10 bulk metallic glass. Based on the experimental data, the sound velocity, density, elastic moduli and Debye temperature were derived as functions of pressure, and the Murnaghan’s equation of state was obtained. Moreover, the compression curve, the elastic constants and the Debye temperature of the bulk metallic glass are calculated on the basis of the similarity between their physical properties in the glass state and those in corresponding crystalline state. These results confirm that the elastic properties of Nd60Al10Fe20Co10 bulk metallic glass are related to its component elements.
DFT total energy study on the atomic geometry and adsorption of Cu(100) c(2×2)-N surface
Authors: Zhao Xin-Xin  , Tao Xiang-Ming  , Chen Wen-Bin  , Chen Xin  , Shang Xue-Fu  , Tan Ming-Qiu  ,   浙江大学物理系,杭州  310027
Published: December 2020

We have performed total energy calculations on the structural and adsorption properties of Cu(100) c(2×2)-N surface by using DFT PAW method. It is concluded that nitrogen adsorbed on a four-fold coordinated site with a perpendicular distance of 0.2? from the surface Cu layer. The shortest Cu-N bond length is calculated to be 1.83?. Geometry optimization calculation excludes the possibilities of adsorbate induced reconstruction mode suggested by Driver and Woodruff and the atop model. The simulated work function for this absorbate-substrate system is 4.65 eV which is quite close to that on the clean Cu(100) surface. The total energy calculations showed that the average adsorption energy per nitrogen atom in the case of Cu(100) c(2×2)-N is about 4.92 eV with respect to a solitude N atom. The absorption of nitrogen on the Cu(100) surface yields the hybridization between surface Cu and N atoms, and generates the localized surface states at -1.0 eV relative to Fermi energy EF. The present study provides a strong criterion to account for the argument on the scanning tunneling microscopy(STM) images from different research groups.
Study on the detection of interfacial bonding strength of coatings (Ⅱ): detecting system of bonding strength
Authors: Zhang Yong-Kang  , Kong De-Jun  , Feng Ai-Xin  , Lu Jin-Zhong  , Ge Tao  ,   (1)江苏大学机械工程学院,镇江  212013; (2)江苏大学机械工程学院,镇江  212013；华东理工大学机械与动力工程学院,上海  200237
Published: December 2020

Stresses and its variation of coating and matrix are measured by XRD (X-ray diffraction). A test system that measures coating stress on the bonding interface is established, and the measurement of interface bonding status is researched. By using interfacial stress variation before and after coating debonding from matrix, combined with the physical parameters of coating material and temperatures field parameter of coating-matrix system, the bonding strength of coating-matrix is represented by the diffraction peak of coating residual stress. A new experiment method to measure bonding strength of coating and matrix is introduced which is applicable to measuring interfacial bonding strength of all kinds of polycrystalline thermal barrier coatings.
Crystal growth and superhardness effects of ZrN/AlON nanomultilayers synthesized by reactive magnetron sputtering
Authors: Liu Yan  , Dong Yun-Shan  , Yue Jian-Ling  , Li Ge-Yang  ,   上海交通大学金属基复合材料国家重点实验室,上海  200030
Published: December 2020

Two series of ZrN/AlON nanomultilayers were synthesized by reactively sputtering zirconium and aluminum oxide targets in the gaseous mixture of argon and nitrogen. The thickness of ZrN layers was fixed in one of the series and the thickness of AlON layers in the other. The composition, microstructure and mechanical properties of films were characterized by X-ray energy dispersive spectroscopy, X-ray diffraction, high resolution transmission electron microscopy and nanoindentation. The investigation results indicate that during the process of Al2O3 target sputtering in the mixed atmosphere, part of oxygen atoms in Al2O3 were replaced by nitrogen atoms, leading to the formation of aluminum oxynitride, AlON. Under the influence of the “template effects” of ZrN layers, the AlON layers that used to exist as amorphous under sputtering conditions were forced to crystallize and grew epitaxially with the ZrN layers when the thickness of AlON was limited to less than 0.9 nm. Correspondingly, the hardness of multilayers was remarkably enhanced to its maximum value of 33.0GPa. A further increase in the thickness of AlON layers led to the crystalline AlON layers transforming into amorphous. The epitaxial growth of multilayers was blocked, accompanied by the decline of hardness.
Influence of arrangement and matrix number on the field emission from conductive nanowire array
Authors: Luo Min  , Wang Xin-Qing  , Ge Hong-Liang  , Wang Miao  , Xu Ya-Bo  , Chen Qiang  , Li Li-Pei  , Chen Lei  , Guan Gao-Fei  , Xia Juan  , Jiang Feng  ,   (1)浙江大学物理系，杭州  310027; (2)中国计量学院物理系，杭州  310018; (3)中国计量学院物理系，杭州  310018;中国计量学院磁学重点实验室,杭州  310018
Published: December 2020

In order to further study the influence of the arrangement and matrix number of the conductive nanowires array on the field emission from the array, the more practical conductive hexagonal and square nanowire arrays were simulated with the mirror image floating sphere model in this paper. From the calculation results, the field enhancement factor of conductive nanowire array was expressed as the following expression:β=h/ρ(1/1+W)+1/2(1/1+W)2+3, in which h is the height of conductive nanowire, ρ is the radius and W is a function of the independent variable R, R is the interwire distance. All calculated results indicated that the arrangement of conductive nanowires array has less influence on the field emission, while the interwire distance critically affects the field emission. As RR0, the field enhancement factor decreases rapidly with R. When R>R0, the enhancement factor hardly changes, where R0 is the optimized interwire distance. The performance of field emission from conductive nanowire array hardly changes with the matrix number of the array, which only influences on the gradient curve of the enhancement factor. R0 would decrease to some extent with the increasing of the matrix number.
Inductive current and conductive current in photoconductor switches
Authors: Qu Guang-Hui  , Shi Wei  ,   西安理工大学物理系，西安  710058
Published: December 2020

Electric pulse of photoconductive switches is determined by transmission character of photo-generated carriers. In the course of transmission, inductive current on the electrodes is formed by photo-generated carriers with high drift speed. Conductive current is formed only after the carriers are absorbed by electrodes. Inductive current and conductive current are calculated by numerical method in this paper. The result shows that inductive current cannot play a main part in the photoconductive switches’ output pulse unless under abnormal test conditions. And explaination of ultra-fast rise time of out put pulse faster than the time of carriers to pass between two electrodes with saturated drift speed is given.
Reconfiguration of GaAs(110) surface with the adsorption of Xe atoms
Authors: Dai Jia-Yu  , Zhang Dong-Wen  , Yuan Jian-Min  ,   国防科学技术大学物理系，长沙  410073
Published: December 2020

First-principle calculations in the frame of density-functional theory (DFT) in the general gradient approximation (GGA) are performed by using the augmented plane wave plus local orbital (APW+lo) method for pure GaAs(110) surface and the adsorptions of Xe atoms on it. A supercell consisting of five atomic layers is constructed to simulate the geometical configuration of clean GaAs(110) surface and the adsorption of Xe atoms. The Newton dynamics method is used to relax the atomic positions. Initiating with the Xe atom on top of Ga atom, As atom, and at the bridge site, respectively, it is found that the total energy of the supercell reaches the minimum when the Xe atoms are located at the bridge site. Additionally, it is shown that the adsorption of Xe atoms make the relaxed GaAs(110) surface to return to the ideal crystal geometrical configuration as generally expected.
Double-level charge storage in self-aligned doubly-stacked Si nanocrystals in SiNx dielectric
Authors: Wang Jiu-Min  , Chen Kun-Ji  , Song Jie  , Yu Lin-Wei  , Wu Liang-Cai  , Li Wei  , Huang Xin-Fan  ,   南京大学物理系，固体微结构国家重点实验室，南京  210093
Published: December 2020

Doubly stacked layers of amorphous silicon (a-Si) between amorphous silicon nitride (a-SiNx) layers have been fabricated by plasma enhanced chemical vapor deposition (PECVD)technique. Si nanocrystal (nc-Si) layers were formed by thermal crystallization of a-Si layers after a furnace annealing at 1100℃ for 30 min in N2 ambient. The phenomena of charge trapping and storage in nc-Si layers were observed in both capacitance-voltage (C-V) and current-voltage (I-V) measurements at room temperature. The structure has revealed a double-level charging process. Two stages of charge storage were evident in the series of C-V curves. The phenomena and mechanism of charge storage were discussed in detail.