bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of particle size on the sinking depth of an object supported by a granular bed
Authors: Peng Zheng  , Hou Mei-Ying  , Shi Qing-Fan  , Lu Kun-Quan  ,   (1)北京凝聚态物理国家实验室，中国科学院物理研究所,北京  100080; (2)北京凝聚态物理国家实验室，中国科学院物理研究所,北京  100080；北京理工大学应用物理系,北京  100081
Published: December 2020

In this paper we briefly review the latest progress on the propagation of stress in granular bed and the resistant force of an object moving in granular media, and report our studies on the grain-size effect, which revals the discrete properties of granular media. We found that the sinking depth of a sphere on a granular bed driven by its own weight decreases monotonically with increasing grain-size. The supporting force of the granular bed experienced by the intruder sphere, during sinking, is measured. It is found that except for about 1 mm depth near the surface, the supporting force and the sinking depth of the sphere is related by a power-law with exponents between 1.5—1.0. The exponent decreases with increasing grain-size. This-size dependence of the power-law relation can be a macroscopic manifest of the reorganization of the stress chains in the granular system during the sinking process of the intruder sphere.
Application of Mie theory in biological tissue scattering characteristics analysis
Authors: Wang Qing-Hua  , Zhang Ying-Ying  , Lai Jian-Cheng  , Li Zhen-Hua  , He An-Zhi  ,   南京理工大学信息物理与工程系，南京  210094
Published: December 2020

Based on equivalent particle scattering model, Mie theory is introduced to calculate the scattering phase function, anisotropy factor and scattering coefficient of biological tissue. Numerical results show that the anisotropy factor and scattering coefficients increase with the increasing of the equivalent particle's diameter when the tissue is irradiated by visible light; the anisotropy factor and scattering coefficients decrease monotonously with the increasing of incident light wavelengths when the equivalent particle's diameter is relatively small; the anisotropy factor and scattering coefficients have no monotonicity with respect to the wavelengths when the equivalent particle's diameter is big. The above numerical results explain the published experiments well.
Transfer property of electron pulse in a femto-second electron diffraction system
Authors: Tian Jin-Shou  , Zhao Bao-Sheng  , Wu Jian-Jun  , Zhao Wei  , Hou Xun  , Liu Yun-Quan  , Zhang Jie  ,   (1)中国科学院物理研究所，北京  100080; (2)中国科学院西安光学精密机械研究所瞬态光学与光子学国家重点实验室，西安  710068
Published: December 2020

An ultra-fast electron diffraction system has been designed. The static and dynamic characters of an electron pulse with 150 fs temporal dispersion are studied during its transmission in the whole ultra-fast electron diffraction system, including the size of the electron spot, temporal dispersion, distribution of azimuths and elevation angles. The initial status of the photoelectrons are put down by Monte Carlo method, both the two dimensional and three dimensional electric fields are calculated by finite difference method and the magnetic flux are calculated by finite element method.
Isospin dependence of three-body force rearrangement contribution
Authors: Zuo Wei  , Xu Zhong-Feng  ,   (1)中国科学院近代物理研究所，兰州  730000; (2)中国科学院近代物理研究所，兰州  730000;西安交通大学理学院，西安  710049
Published: December 2020

Within the isospin-dependent Brueckner framework, we investigate the contribution of three-body force (TBF) rearrangement to isospin symmetry potential as well as its momentum and density dependence.In particular, we investigate the TBF rearrangement effects on the isospin splitting of neutron and proton effective masses in neutron-rich nuclear matter. We show that the rearrangement contribution of TBF to neutron and proton single-particle potentials is repulsive and increases rapidly with increasing density and momentum. At low densities, the influence of the TBF rearrangement on symmetry potential is rather small, and the TBF rearrangement effect becomes more and more pronounced as the density rises. At high densities, the contribution of TBF rearrangement increases considerably the symmetry potential and modifies remarkably the momentum dependence of the symmetry potential. In both cases with and without including the TBF rearrangement contribution, the predicted neutron effective mass in neutron-rich matter is greater than the proton effective mass. The TBF rearrangement effect is to decrease remarkably both the proton and neutron effective masses, and reduce the magnitude of neutron-proton effective mass splitting in neutron-rich matter at high densities.
Effect of Nb addition on the glass transition and crystallization kinetics of bulk Cu-Zr metallic glasses
Authors: Fang Qi  , Wang Qing  , Zhao Zhe-Long  , Dong Yuan-Da  ,   上海大学材料研究所，上海 200072
Published: December 2020

In the present work, bulk Cu50.3Zr49.7-xNbx(x=0,2) amorphous alloys 2　mm in diameter were produced by copper mold suction casting. The effect of Nb addition on the glass transition as well as crystallization kinetics of the binary Cu based amorphous alloy has been investigated by using differential scanning calorimetry (DSC). It is found that the alloy containing 2%Nb has a lower fragility parameter m and higher crystallization activation energy Ec, which suggests that the thermal stability and hence the glass forming ability of the surpercooled metallic liquid for the Cu based alloy are enhanced by the addition of very small amounts of Nb element.
Regular and chaotic motions of a single trapped ion interacting with a flashing ratchet potential
Authors: Chen Wen-Qin  , Hai Wen-Hua  , Li Hui  , Ma Zhi-Ying  ,   (1)湖南师范大学物理系,长沙 410081; (2)湖南师范大学物理系,长沙 410081;华南热带农业大学基础学院，儋州 571737; (3)华南热带农业大学基础学院，儋州 571737
Published: December 2020

Under the pseudopotential approximation, for a single Paul trapped ion which interacts with a flashing ratchet potential formed by two laser standing waves, we apply the method of integral-equation to construct the exact solution of the classical equation, and use the numerical technique to plot the orbits in phase space and calculate the current defined by the average velocity. By combining the analytical results with numerical ones,we investigate the regular and chaotic motions of the system. Compared to the case of the flashing lattice potential, two important ratchet effects are found here: First, the flashing ratchet potential changes the chaotic region in the parameter space such that we can make the regular motion of ion chaotic or vice versa by adjusting the parameters of the second laser. Secondly, by analyzing the evolutions of the average current versus the laser parameters, we find that the presence of the flashing ratchet potential can lead the trapped ion to be transported in averagy along a single direction. When the potential strength is increased to the chaotic region, the current decreases evidently and its direction varies, indicating the onset of chaotic motion.
Self-consistent variational calculation of the dense fluid helium plasma in the region of partial ionization
Authors: Zhang Ying  , Chen Qi-Feng  , Gu Yun-Jun  , Cai Ling-Cang  , Lu Tie-Cheng  ,   (1)四川大学物理系,辐射物理及技术教育部重点实验室,成都 610064; (2)中国工程物理研究院流体物理研究所冲击波物理与爆轰波物理实验室,绵阳 621900; (3)中国工程物理研究院流体物理研究所冲击波物理与爆轰波物理实验室,绵阳 621900;四川大学物理系,辐射物理及技术教育部重点实验室,成都 610064
Published: December 2020

The dense fluid helium will be ionized under high pressures and temperatures. The ionization energy of helium will be lowered as the result of interactions between all particles of He, He+, He2+, and e. In this paper, the thermodynamic parameters are obtained from nonideal ionization equilibrium, taking into account the correlation contributions to the chemical potential which is determined self-consistently by the free energy function. The theoretical equation of state (EOS) is verified by shock compression experiments and other theoretical calculations. The EOS of dense helium plasma are predicted and the contributrions of interactions are discussed for the density and temperature range of 10-3—100.3 g/cm3 and 4—7 eV, respectively. The calculations show that the pressure ionization is caused by the reduced ionization energy induced by the nonideal interactions, and the ionization energy should be corrected at high temperatures and densities.
Isospin effect in the nuclear reaction induced by neutron-halo nuclei
Authors: Liu Jian-Ye  , Zuo Wei  , Lee Xi-Guo  , Xing Yong-Zhong  ,   (1)天水师范学院数理信息学院基础物理研究所,天水 741000;中国科学院近代物理研究所,兰州 730000;重离子加速器国家实验室原子核理论中心,兰州 730000; (2)天水师范学院数理信息学院基础物理研究所,天水 741000;重离子加速器国家实验室原子核理论中心,兰州 730000; (3)中国科学院近代物理研究所,兰州 730000;重离子加速器国家实验室原子核理论中心,兰州 730000
Published: December 2020

We study the average property of the isospin effect of reaction induced by halo-neutron nuclei 8He and 10He in the intermediate energy heavy ion collisions using the isospin-dependent quantum molecular dynamics model (IQMD). This study is based on the extended neutron density distribution for the halo-neutron nuclei, which includes the average property of the isospin effect of reaction mechanism and loose inner structure. The extended neutron density distribution brings an important isospin effect into the average property of reaction mechanism because the interaction potential and nucleon-nucleon(N-N)cross section in IQMD model depend sensitively on the density distribution of colliding system. In order to see clearly the average properties of reaction mechanism induced by halo-neutron nuclei we also compare the results for the neutron-halo colliding systems with those for the corresponding stable colliding systems under the same incident channel condition. We found that the extended density distribution for the neutron-halo projectile brings an important isospin effect to the reaction mechanism, which leads to the decrease of nuclear stopping R, yet induces obvious increase of the neutron-proton ratio of nucleon emissions and isospin fractionation ratio for all beam energies studied in this work, compared to the corresponding stable colliding system. In this case, nuclear stopping, the neutron-proton ratio of nucleon emissions and isospin fractionation ratio induced by halo-neutron nuclei can be used as possible probes for studying the average property of the isospin effect of reaction mechanism and extracting the information of symmetry potential and in-medium N-N cross section by the neutron-halo nuclei in heavy ion collisions.
Study on two-cell stimulated Brillouin scattering system with new media
Authors: Hasi Wu-Li-Ji  , Lü Zhi-Wei  , Li Qiang  , Ba De-Xin  , 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

According to the relationships between the chemical structure of the medium and the absorption coefficient, a series of new media with small absorption coefficients has been found, which are suited for use as the amplifier media. The stimulated Brillouin scattering (SBS) parameters of these media have been calculated or measured when the pump wavelength is 1.064 μm. Choosing C2Cl4 and C4Cl6 as amplifier medium and C2H5OH as generator medium, we investigated the performances of two-cell SBS system pumped by Nd:YAG Q-switched laser. The C2H5OH has a high optical breakdown threshold and the Brillouin frequency shift of C2H5OH is close to those of C2Cl4 and C4Cl6. The results indicate that the system has the characteristics of high power-load ability, high phase-conjugation fidelity and high energy reflectivity stability.
Field emission from single diamond particle
Authors: Yuan Guang  , Guo Da-Bo  , Gu Chang-Zhi  , Dou Yan  , Song Hang  ,   (1)中国海洋大学物理系，青岛  266100; (2)中国科学院长春光学精密机械与物理研究所，长春  130033; (3)中国科学院物理研究所表面物理重点实验室，北京  100080
Published: December 2020

The I-V characteristics of　a diamond particle deposited by hot-filament chemical vapor deposition on a tungsten tip was measured in a dual-probe scanning electron microscope (DP-SEM) chamber by introducing Mo tips into the chamber as a measurement probe. The I-V characteristic of well crystallized diamond particle follows Ohm's law, and no field electron emission was observed, while the cauliflower-like particle satisfies the Pool-Frenkel (PF) theory and the field emission was observed clearly. These results are contributed to the defects in CVD diamond.
Effects of temporal chirp on laser filamentation in air
Authors: Wang Zhao-Hua  , Hao Zuo-Qiang  , Zhang Zhe  , Lu Xin  , Jin Zhan  , Zhong Jia-Yong  , Liu Yun-Quan  , Wei Zhi-Yi  , Zhang Jie  , Zhao Gang  ,   (1)中国科学院国家天文台，北京 100012; (2)中国科学院物理研究所光物理实验室，北京 100080; (3)中国科学院物理研究所光物理实验室，北京 100080;中国科学院国家天文台，北京 100012
Published: December 2020

Effect of the laser chirp on the laser filamentation is investigated. It is found that the chirp plays a crucial role in the formation of filamentation and its evolution. An initial negative chirp is favorable for long-distance propagation of filaments in air. As the chirp increases, the distance between the compressor and the position of the onset of filaments becomes larger. We also investigate the influence of initial chirp on the focusing laser pulses by a lens. It is found that there are the same tendency of filaments formed by lens and those in free propagation.
Polarization dependence of third-harmonics and spectral modulation properties of supercontinuum radiation from plasmas channels generated by femtosecond laser pulses propagation in air
Authors: Li Kun  , Xu Miao-Hua  , Jin Zhan  , Liu Yun-Quan  , Wang Zhao-Hua  , Ling Wei-Jun  , Zhang Jie  ,   中国科学院物理研究所光物理实验室，北京 100080
Published: December 2020

We carried out spectroscopic studies on the supercontinuum radiation from the plasma channels generated by femtosecond laser pulses propagating in air, which confirmed the polarization dependence of third harmonics and the spectral modulation of supercontinuum radiated from filaments. The new phenomenon of spectral modulation is also explored.
Enhancement factor formulation of doped nematic liquid crystals in the presence of photoisomerization
Authors: Deng Luo-Gen  , Luo Li-Yuan  ,   北京理工大学理学院物理系，北京 100081
Published: December 2020

The mechanism of the orientational optical nonlinearity enhancement in the azo-dye doped liquid crystals is studied. The expressions of the enhancement factors based on the multiple-level transition model of azo-compound are derived. Our results show that, the simpler the model, the fewer the number of items contained in the expression of the enhancement factor. Using the enhancement factor expression obtained by the four-level model to describe the influences of the photoisomerization of azo-dyes on the enhancement of orientational optical nonlinearity is better than using that acquired by the three-level model. Besides, the expression of the enhancement factors in the case that the cis molecules do not absorb light is also obtained from the enhancement factor expression obtained by the four-level model. Except for a minor difference, the enhancement factor expression obtained in this case is the same as what was obtained for the anthraquinone-dye doped liquid crystals by Marrucci et al in 1997. This result also shows that under a given simplified condition, our theory is consistent with the last theory.
The dual-species model study of co-enrichment of trace elements and Ni at Ni3Al grain boundary
Authors: Zheng Li-Ping  , Li Dou-Xing  , Xu Zi-Jian  , Zhu Zhi-Yuan  ,   (1)中国科学院金属研究所，沈阳 110016; (2)中国科学院上海应用物理研究所,上海 201800; (3)中国科学院上海应用物理研究所,上海 201800;中国科学院国际材料物理中心,沈阳 110016
Published: December 2020

The dual-species model is based on the Monte Carlo simulation conjoined with the embedded atom method (EAM) potentials. The model suggests that during relaxation of Ni3Al grain boundary，the trace element atoms can be seen not only as segregating species but also as inducing species. As segregating species the trace element atoms segregate (or enrich) to the grain boundary, but as inducing species they induce Ni atoms to segregate (or enrich) to the grain boundary. Evidently, the model can explain why the trace element atoms and Ni atoms co-segregate (or co-enrich) to the grain boundary. According to combination of positive (as inducing species) and negative (as segregating species) effects, the model explains the most obvious Ni-enrichment phenomenon at Ni3Al grain boundaries.
Calculating elastic constants of Fe-based cubic magnetic material using first principles
Authors: Zheng Lei  , Jiang Cheng-Bao  , Shang Jia-Xiang  , Zhu Xiao-Xi  , Xu Hui-Bin  ,   材料科学与工程学院，北京航空航天大学，北京 100083
Published: December 2020

Using the first principles full potential linearized augmented plane wave (FLAPW) method and the pseudopotential plane wave (CASTEP) method, the elastic constants of Fe-based magnetic cubic phases are investigated. The key point is confirmed to be the lattice constants when calculating elastic constants, and the basis sets also affect the precision of calculation. More precise results were got by FLAPW. The elastic constants C11, C12, C44 of bcc-Fe are 283 GPa, 158 GPa and 112 GPa, respectively，which approximately consist with the intrinsic ones. The elastic constants C11, C12, C44 of Fe-Ga magnetostrictive material are calculated to be 207 GPa, 166 GPa and 108 GPa, respectively.
First-principles calculations of structures, properties and high pressures effects of Fe
Authors: Sun Bo  , Liu Shao-Jun  , Duan Su-Qing  , Zhu Wen-Jun  ,   (1)北京师范大学物理系，北京 100875;北京应用物理与计算数学研究所，北京 100088; (2)北京应用物理与计算数学研究所，北京 100088; (3)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理国防重点实验室，绵阳 621900
Published: December 2020

In this paper, we performed first-principles calculations for iron with different crystal structures based on density-function theory, employing the pseudopotentional and plane-wave method. We set the computational precision of energy to 0.01 eV/atom and made total-energy calculations. The calculated results show that: 1) The bcc iron undergoes a pressure-induced phase transform to hcp structure at about 15 GPa, which is in good-agreement with the experimental values; 2) The magnetic moment decreases with increasing pressure, which demonstrates that the high pressures will destroy the magnetism of iron; 3) The ratio of lattice parameters of hcp structure, c/a, will slowly increase with the pressure increasing. When set to a constant about 1.59, the c/a value can give the energy computation precision of 0.01 eV/atom under the pressures in the earth core.
Grating optimization and experiment on high-power distributed feedback lasers
Authors: Fu Sheng-Hui  , Song Guo-Feng  , Chen Liang-Hui  ,   中国科学院半导体研究所，北京 100083
Published: December 2020

Coupling coefficient is an important parameter for distributed feedback lasers. Modified coupled-wave equations are used to calculate the effect of grating shape on coupling coefficient of the second-order gratings. Corresponding devices demonstrate that the maximum kink-free power per facet reaches 50 mW and the sidemode suppression ratio is 36 dB.
The calculation of electronic structure in GaN/AlN quantum dots with finite element method
Authors: Liang Shuang  , Lü Yan-Wu  ,   北京交通大学理学院，北京 100044
Published: December 2020

We investigate electronic structure theoretically in strained GaN/AlN quantum dots (QDs) with wurtzite (WZ) crystal structure. The QD electron energy levels are calculated using the finite element method (FEM) in the framework of effective mass approximation (EMA). We analyze the influence of strain and polarization to the electron energy levels and calculate electron energy levels with different dot sizes. It is shown that the strain dependent deformation potential and piezoelectric potential increase the electron energy levels and split the degenerate states. The electron energy levels decreases rapidly with increasing QD height, which is partly due to the confinement energy reduction. However, the piezoelectric field makes a more significant contribution.
The effective magnetic anisotropy of nanocrystalline Fe39.4－xCo40Si9B9Nb2.6Cux alloys
Authors: Han Xian-Tang  , Wang Zhi  , Ma Xiao-Hua  , Wang Guang-Jian  ,   (1)河北工程大学理学院，邯郸 056038; (2)天津大学理学院，天津 300072
Published: December 2020

The effective magnetic anisotropy of nanocrystalline Fe39.4-xCo40Si9B9Nb2.6Cux alloysHan Xian-Tang1) Wang Zhi1) Ma Xiao-Hua1) Wang Guang-Jian2)The effective magnetic anisotropy 〈K〉 of nanocrystalline Fe39.4-xCo40Si9B9Nb2.6Cux(x=0.5,1,1.5) alloys annealed at different temperatures was investigated based on the law of approach to saturation at room temperature. The experimental results showed that the grain size D of samples with low content of Cu (x=0.5) is larger and a hard magnetic phase precipitated from the residual amorphous matrix at lower annealing temperature which lead to a higher value of 〈K〉. And with increasing content of Cu, which effectively refined the grains and retarded the formation of borides at x≥1,a clear drop tendency of 〈K〉 was observed. The correlation between 〈K〉 and D as well as 〈K〉 and initial permeability μi was also discussed.
Peculiar transport properties and CMR effect of La0.67Sr0.08Na0.25MnO3
Authors: Peng Zhen-Sheng  , Tang Yong-Gang  , Yan Guo-Qing  , Guo Huan-Yin  , Mao Qiang  ,   (1)宿州学院巨磁材料研究室，宿州 234000; (2)宿州学院巨磁材料研究室，宿州 234000；中国科学技术大学结构分析重点实验室，合肥 230026
Published: December 2020

The La0.67Sr0.08Na0.25MnO3 sample was prepared by solid-state reaction. The transport properties and CMR effect of the sample were studied through M-T curves, ρ-T curves and ρ-T fitted curves. The results show that: Both the ρ-T curves and the MR-T curve exhibit the double-peak phenomenon; the high-temperature peak corresponds to the I-M transition accompanied by the PM-FM transition, and the low-temperature peak is attributed to grain boundary effect. The two insulator phases have different transport mechanisms: in the low temperature range(248 KTρ(T) accords with variable-range-hopping model of polaron, while in the high temperature range(330 KTρ(T) accords with near- neighbor- hopping model of polaron; and the two metal-like phases also have different transport mechanisms: in the low temperature range(67 KTρ(T) accords with the ρ-T2.5 relation, and the transport mechanism is the actions of spin wave scattering and electron-magneton scattering, while in the high temperature range(292 KTρ(T) accords with the ρ-T2 relation, and the transport mechanism is single magneton scattering.
Study on FN-DLC thin films: (Ⅱ) effect of radio frequency power on the optical band gap of the thin films
Authors: Xiao Jian-Rong  , Xu Hui  , Guo Ai-Min  , Wang Huan-You  ,   (1)中南大学材料科学与工程学院，长沙 410083; (2)中南大学物理科学与技术学院，长沙 410083; (3)中南大学物理科学与技术学院，长沙 410083；中南大学材料科学与工程学院，长沙 410083
Published: December 2020

FN-DLC thin films, radio-frequency power, optical band gap
Recursive calculation of higher order focus values for a class of nonlinear systems
Authors: Chen Song-Lin  , Nian Ya-Dong  ,   安徽工业大学数理学院，马鞍山 243002
Published: December 2020

A class of higher power nonlinear systems with higher order singular point are discussed in the paper. A series recursive equations for the calculation of focus value are obtained. An application on power-5 system are given and the concrete simulation verifies the theory.
Quantum key distribution based on hyperentanglement swapping
Authors: Feng Fa-Yong  , Zhang Qiang  ,   中国科学技术大学近代物理系，合肥 230026
Published: December 2020

We present a quantum key distribution scheme based on hyperentanglement swapping, which can simultaneously generate deterministic and random keys without the loss of security. The scheme only requires two\|photon states entangled both in spatial (path) and polarization modes, and such a photon pair can create 4 bit of secure keys (2 bit of random keys and 2 bit of deterministic keys). Our protocol can be implemented with linear optics under current technology.
A new chaotic system and its circuit simulation
Authors: Liu Ling  , Su Yan-Chen  , Liu Chong-Xin  ,   (1)西安交通大学电气工程学院，西安 710049; (2)西南交通大学机械工程学院,成都 610031
Published: December 2020

In this paper a new chaotic system is presented. Some basic dynamical properties are investigated. The oscillator circuit relizing the new chaotic system is simulated using Electronics Workbench (EWB). Continuous spectrum, Lyapunov exponents, fractal dimension and strange attractor of the system are studied.
Waveguide induced by bright holographic solitons
Authors: Zhang Hui-Lan  , Zhang Guang-Yong  , Wang Cheng  , Liu Shi-Xiong  , Liu Jin-Song  ,   华中科技大学光电科学与技术学院，武汉  430074
Published: December 2020

The properties of waveguides induced by one-dimensional steady-state bright holographic solitons in photorefractive medium are studied numerically. The results show that the number of possible guided modes in such a waveguide depends on the peak intensity of the soliton. The dynamical evolutions of the guided modes of the waveguide are presented. And the wave guiding in such a waveguide is also considered for a probe beam with cosine dependence or sine dependence.
Classified prediction of geomagnetic disturbance caused by coronal mass ejection
Authors: Wang Jing  , Feng Xue-Shang  ,   (1)中国科学院空间科学与应用研究中心空间天气学国家重点实验室,北京 100080; (2)中国科学院空间科学与应用研究中心空间天气学国家重点实验室,北京 100080;中国科学院研究生院,北京 100049
Published: December 2020

The characteristics of accelerating coronal mass ejection (CME) and decelerating CME happening during 1997—2003 are analyzed. Prediction tests are made for geomagnetic disturbance events caused by the gradually accelerating CME-associated interplanetary shock waves and the decelerating CME-associated interplanetary shock waves, which can be identified by interplanetary scintillation (IPS) observation during 1997—2003. New membership functions and new correctional item of onset time of geomagnetic disturbances are respectively constituted for two kinds of CME. The main results are: for the onset time of the geomagnetic disturbance in the accelerating CME, the relative error between the observation,Tobs, and the prediction,Tpre,ΔTpre/Tobs≤10% for 21.86% of all events, ≤30% for 78.13% and ≥50% for only 9.36%; for the decelerating CME, ΔTpre/Tobs≤10% for 25.00% of all events, ≤30% for 84.37% and ≥50% for only 3.13%.These results show that the method has good feasibility for the geomagnetic disturbance predictions.
Investigation of the beam evolution in nonlinear optical lattice
Authors: Zhuo Hui  , Fu Xi-Quan  , Wu Jin-Hua  , Wen Shuang-Chun  ,   湖南大学计算机与通信学院，长沙  410082
Published: December 2020

The paper studies the beam evolution of optical lattice, i.e. media with transverse periodic lattice modulation in the propagation radiation. Using the variational principle,the forms are obtained for the evolution duing propagation of beam width, beam amplitude and frequency chirp. Next, the conditions for soliton formation in nonlinear optical lattice are discussed and the different propagation processes with different beam conditions are obtained. There are analogous characteristics in the actions of periodic lattice potential of optical lattice and nonlinear media. The periodic potential offers a better method to control the lattice soliton formation and propagation.
Least action principle for dissipative solitons and its application in two-dimensional PBG structure
Authors: Tan Kang-Bo  , Liang Chang-Hong  ,   西安电子科技大学天线与微波国家重点实验室，西安 710071
Published: December 2020

Dissipative and coherent effects of X-point solitons are investigated on the basis of dynamic variational formulation in two-dimensional photonic bandgap (PBG) structure of square lattice. Through the least action principle, the result deduced from analyzing soliton parametric equations indicates that dissipative effect leads to not only amplitude decrease but also section expansion of solitons. In addition, co-soliton interaction for negative potential is decreased by dissipation, and bound sate of solitons in x direction is also weakened. Amplitude and period of fluctuation of relative interval between soliton centers increase in x direction, when x increases to some value, relative interval will increase continuously.
Resonant frequency shift in coupled photonic crystal defects described by the tight-binding method
Authors: Cai Xu-Hong  , Lin Xu-Sheng  , Shi Quan  , Zhao Nian-Shun  ,   汕头大学物理系，汕头 515063
Published: December 2020

The resonant frequency splitting caused by photonic crystal (PC) defect coupling can be well described by the tight-binding (TB) approximation in which only two coupling parameters are used. However, the description of the resonant frequency shift that represents the difference between the center resonant frequency of the coupled structure containing odd number of defects and the resonant frequency of a single defect, requires the employment of the rigorous TB that involves three coupling parameters. By using the relation between the coupling parameters and the resonant frequencies, we extract the values of the three coupling parameters from the simulation of a three-coupled-defect structure and use them to predict the resonant frequency shift and splitting of the coupled structures consisting of arbitrary number og PC defects. They are in good agreement with the simulation results based on the finite-difference time-domain method.
Determination of chemical composition and average crystal lattice constants of InGaN/GaN multiple quantum wells
Authors: Ding Zhi-Bo  , Wang Qi  , Wang Kun  , Wang Huan  , Chen Tian-Xiang  , Zhang Guo-Yi  , Yao Shu-De  ,   (1)北京大学物理学院,北京 100871; (2)宽禁带半导体研究中心,北京 100871
Published: December 2020

The samples of InGaN/GaN multiple quantum wells (MQWs) have been grown on (0001) sapphire substrate with n-GaN buffer layer by metal-organic chemical vapor deposition (MOCVD). According to the results of Rutherford backscattering (RBS)/channeling along 〈0001〉 axis, the conventional θ—2θ scans normal to GaN (0004) and (1014) plane at 0° and 180° azimuth angles and the photoluminescence (PL) properties at room temperature, we concluded that In atoms in the InGaN/GaN MQWs are highly substituted, with the substitution rate over 99%, and the average crystal lattice constants of InGaN/GaN MQWs were calculated accurately (aepi=0.3195nm，cepi=0.5198nm), which are almost equal to theoretical data. Using HRXRD and RBS,the atomic content of In was determined to be respectively 0.023 and 0.026, the result was consistent with actual growth conditions of InGaN/GaN MQWs. However,there was a great difference compared with In chemical composition obtained by PL properties, which shows that PL properties are not suitable for measuring the In chemical composition in InGaN/GaN MQWs.
Spectroscopic properties and energy transfer of Tm3+/Ho3+-codoped Ga2O3-Bi2O3-GeO2-PbO-PbF2 glasses for 1.47μm luminecence
Authors: Shi Dong-Mei  , Zhang Qin-Yuan  , Yang Gang-Feng  , Jiang Zhong-Hong  ,   特种功能材料及其制备新技术教育部重点实验室,华南理工大学光通信材料研究所，广州 510640
Published: December 2020

This paper reports on the spectroscopic properties and energy transfer of Tm3+/Ho3+-codoped 14Ga2O3-25Bi2O3-20GeO2-31PbO-10PbF2 glasses. The Judd-Ofelt intensity parameters Ωt(t=2，4，6), spontaneous-emission probability, branch ratio and radiative lifetime of each level of Tm3+ have been calculated by Judd-Ofelt theory. The effective bandwidth and peak emission cross-section of the 3H4→3F4 transition (1.47μm) of Tm3+ have also been obtained. Codoping of Ho3+ significantly decreased the population of 3F4 level of Tm3+, while the population of 3H4 level of Tm3+ reduced slightly. Our results indicate that GGBPF glass is a promising candidate for 1.47μm optical amplifiers, and Ho3+ is an effective codopant to enhance the 1.47μm luminescence.
Lie symmetries of discrete Lagrange systems
Authors: Shi Shen-Yang  , Fu Jing-Li  , Chen Li-Qun  ,   (1)上海大学上海市应用数学与力学研究所，上海  200072; (2)浙江理工大学物理系，杭州  310018; (3)浙江理工大学物理系，杭州  310018; 上海大学上海市应用数学与力学研究所，上海  200072
Published: December 2020

This paper studies the Lie symmetries of discrete Lagrange systems. Based on discrete variational principle, the equations of motion for the discrete systems are established. Definition of Lie symmetry and determining equations for the discrete equations of motion are given. An example is presented to illustrate the application of the results.
Time operator in quantum mechanics
Authors: Wang Zhi-Yong  , Xiong Cai-Dong  ,   电子科技大学物理电子学院，成都  610054
Published: December 2020

There have been great theoretical and practical interests in investigating time problem in quantum mechanics. Because time enters quantum mechanics as a parameter rather than a dynamical operator, people have to consider how to construct a time operator and calculate average time whenever they are faced with a time problem related to a physical process. In this paper we present a general investigation on time operator and average time.
Study on solid-solid interface waves with laser ultrasonics
Authors: Han Qing-Bang  , Qian Meng-Lu  , Zhu Chang-Ping  ,   (1)河海大学计算机与信息工程学院常州校区，常州  213022; (2)河海大学计算机与信息工程学院常州校区，常州  213022;同济大学声学研究所，上海  200092; (3)同济大学声学研究所，上海  200092
Published: December 2020

The propagation characteristics of interface waves are studied theoretically and experimentally. The problem of solving for roots of characterization equation of interface waves are discussed. It is shown that all roots can be found by means of Riemann sheet analysis. The propagation mechanism of Stoneley wave, Leaky Rayleigh and Leaky interface waves are explored, the wave vector and displacement behaviors of these waves are illustrated to show their differences. At last, the interface waves are measured with laser ultrasonic technique based on photo-elastic effect, and the experimental results are in good agreement with theoretical predictions.
CTMC calculation of O3++He impact processes
Authors: Liu Chun-Lei  , He Bin  , Yan Jun  , Wang Jian-Guo  ,   北京应用物理与计算数学研究所计算物理实验室，北京  100088
Published: December 2020

The O3++He collision processes are studied ultilizing a classical trajactory Monte-Carlo (CTMC) method. The initial microcanonical distribution is modified by using eleven different ionization thresholds of electrons in tht target. The total cross sections of all processess as functions of the projectile energy are calculated. For a test, the process of He2++He is calculated and the agreement with experiment is improved by the modified distribution.The total cross sections of O3++He including single- and double-electron ionization and transfer ionization are obtained in the energy range from 3 keV/u to 1 MeV/u, which are found in good agreement with the experiment. But there exists some large difference for the ratio of transfer ionization to single-electron capture, which requires further theoretical and experimental investigations.
Vectorial chaotic synchronization characteristics of unidrectionally coupled and injected vertical-cavity surface-emitting lasers based on optical feedback
Authors: Zhong Dong-Zhou  , Xia Guang-Qiong  , Wang Fei  , Wu Zheng-Mao  ,   (1)五邑大学信息学院，江门 529020; (2)西南大学物理学院，重庆 400715; (3)重庆工学院数理学院，重庆 400050
Published: December 2020

Based on the Spin Flip Model (SFM), vectorial chaotic synchronization characteristics of vertical-cavity surface-emitting semiconductor lasers (VCSELs) with isotropic optical feedback is numerically investigated. The results are as follows. First, when the external cavity round-trip time equals the propagation time of light from the transmitter to the receiver, both the x-linear polarization (LP) mode and the y-LP mode can realize very high complete synchronization. Second, when external cavity round-trip time is not equal to the propagation time and μ is near the lasing threshold, the better completely synchronized quality of the dominant y-LP mode can be temporarily achieved. In comparison, the governing x-LP mode can only realized poor synchronization quality. In addition, with the system governed by the mixed LP modes, each LP mode can obtain inferior synchronization quality. However, with injection current much greater than the threshold current, the completely governed y-LP mode can steadily achieve the best chaotic synchronization quality. At last, each LP mode of the injection can achieve good injection-locking synchronization with that of the receiver. While each dominant LP mode can obtaine poorer injection-locking synchronization quality than the corresponding suppressed LP mode, with equal power, two LP modes both can achieve almost identical high injection-locking synchronization quality. Namely, the LP state with less power can be obtain better injection-locking synchronization.
Research on 2.5-dimensional nonlinear beam-wave interaction program of klystrons
Authors: Zhao Ding  , Ding Yao-Gen  , Wang Yong  ,   (1)中国科学院电子学研究所,北京 100080; (2)中国科学院电子学研究所,北京 100080；中国科学院研究生院,北京 100039
Published: December 2020

In high perveance klystrons, violent variation of electron beam radius and electron transverse velocity is met with, and the energy exchange between kinetic electrons and gap field is a nonlinear process. For accurately describing these physical phenomena, we have put forward the corresponding physical model and further developed the 2.5-dimensional computation program LSP. Moreover, by use of this tool, we analyzed a practical S-band high peak-power klystron in detail. By comparing with the calculation results using 1-dimensional program and experimental data, we noticed that this poly-dimensional program can approach the real situation with higher precision.
Numerical research on intense pulsed ion beam ablation plasma expansion into ambient gases
Authors: Wu Di  , Gong Ye  , Liu Jin-Yuan  , Wang Xiao-Gang  , Liu Yue  , Ma Teng-Cai  ,   (1)大连理工大学三束材料改性国家重点实验室，大连  116024; (2)大连理工大学三束材料改性国家重点实验室，大连  116024;大连轻工业学院信息科学与工程学院，大连  116034
Published: December 2020

The mechanisms are different for intense pulsed ion beam ablation plasma expanding into ambient gas of different pressure or into vacuum. The former is complicated by the interaction between plasma and the ambient gas. The 2D gas dynamical model has been built to describe the process, and the plasma expansion into ambient gas of pressures from 10-6 atmosphere to 1 atmosphere have been calculated. The results show that the phenomena of plasma expanding into ambient gases vary as the pressure changes. It can expand into vacuum freely, but into atmosphere its movement is confined. And the ejection into ambient gas of one thousandth atmosphere or so is special, the ‘snowplow’ phenomenon is observed and the plume plasma splits into fast- and slow-moving parts.
A comparison of energy distribution of hot electrons from the front and the rear sides of targets during the interaction of femtosecond laser with foil targets
Authors: Cai Da-Feng  , Gu Yu-Qiu  , Zheng Zhi-Jian  , Zhou Wei-Min  , Jiao Chun-Ye  , Wen Tian-Shu  , Chunyu Shu-Tai  ,   (1)中国工程物理研究院激光聚变研究中心，绵阳  621900; (2)中国工程物理研究院激光聚变研究中心，绵阳  621900;内江师范学院物理系，内江  641112
Published: December 2020

The energy distribution of hot electrons from the front and the rear sides of targets have been measured during the interaction of femtosecond laser with the foil target. The results show that the peaks of energy spectrum of hot electrons from the front and the rear sides of targets are located at 430 keV and 175 keV, respectively. Fitted with Maxwell distribution, the temperatures of hot electrons from the front of targets are 218 keV and 425 keV. Obviously, the energy spectrum of hot electrons from the rear of targets is “softened”, which is due to Debye sheath electric field and self-magnetic field produced by hot electrons transported in the target, and has temperatures of 96 keV and 347 keV, which are lower than those from the front of targets.
Dependence of anisotropically conductive adhesive high-frequency signal transmission on conductive particle property
Authors: Wu Yan-Rui  , Chen Xiao-Shuang  , Fu Ying  , Lu Wei  ,   中国科学院上海技术物理研究所红外物理国家实验室，上海 200083
Published: December 2020

Using differential method, we have calculated the dependence of anisotropically conductive adhesive high-frequency signal transmitting property on conductive particle property (including the shape and size of particles). Under AC bias, the smaller the size of conductive filler particle in the conductive adhesive, the better conductance it has. Through the theoretical calculation, we found that the conductance is inversely proportional to the radius (side length) if the shape of the conductive metal particle is a sphere (cube). If the shape of the metal particle is a cuboid or cylinder, the conductance is inversely proportional to the height, independent of the changes in the base.
Experimental study on Kα X-ray emission from intense femtosecond laser-solid interactions
Authors: Xu Miao-Hua  , Chen Li-Ming  , Li Yu-Tong  , Yuan Xiao-Hui  , Liu Yun-Quan  , Kazuhisa Nakajima  , Toshi Tajima  , Wang Zhao-Hua  , Wei Zhi-Yi  , Zhao Wei  , Zhang Jie  ,   (1)Advanced Photon Research Center,Japan Atomic Energy Research Institute,Kyoto,Japan,619-0215; (2)中国科学院物理研究所光物理实验室，北京  100080; (3)中国科学院物理研究所光物理实验室，北京  100080;中国科学院西安光机所瞬态光学国家重点实验室，西安  710068; (4)中国科学院西安光机所瞬态光学国家重点实验室，西安  710068
Published: December 2020

The characteristics of Kα X-ray sources generated by p-polarized femtosecond laser-solid interactions are experimentally studied in the relativistic regime. By use of knife-edge image technique and a single-photon-counting X-ray CCD camera, we obtaine the source size, the spectrum and the conversion efficiency of the Kα X-ray sources. The experimental results show that the conversion efficiency of Kα photons reaches an optimum value of 7.08×10-6/sr at the laser intensity of 1.6×1018W/cm2, which is different from the Reich's simulation results (Reich et al., 2000 Phys. Rev. Lett. 84 4846). We find that about 10% of laser energy is converted into the forward hot electrons at the laser intensity of 1.6×1018W/cm2.
Approximate solution for a class of atmospheric wading wave equations
Authors: Mo Jia-Qi  , Lin Wan-Tao  ,   (1)LASG，中国科学院大气物理研究所,北京 100029; (2)安徽师范大学,芜湖 241000;上海高校计算科学E-研究院上海交通大学研究所，上海 200240;湖州师范学院，湖州 313000
Published: December 2020

In this paper, a class of wading wave equations are considered. Using the homotopic mapping theory and method, the corresponding approximate solution of the system is obtained.
Phase synchronization and generalized synchronization in doubly driven chaotic oscillators
Authors: Wu Yu-Xi  , Huang Xia  , Gao Jian  , Zheng Zhi-Gang  ,   (1)北京师范大学物理系,北京 100875; (2)北京师范大学物理系,北京 100875;高等教育出版社,北京 100011; (3)北京师范大学物理系,北京 100875;中国矿业大学理学院,徐州 221008; (4)华北电力大学数理系,北京 102206
Published: December 2020

Phase synchronization(PS) and generalized synchronization(GS) of a chaotic oscillator driven by two chaotic signals is investigated. Anti-biased PS and biased GS in the presence of biased coupling are found, i.e., the response oscillator can be phase synchronized (generally synchronized) by the drive with a weaker (stronger) coupling rather than the stronger (weaker) driver. The mechanism for these behaviors are explored.
Periodic oscillation of rare-gas atoms in carbon nanotubes
Authors: Jin Nian-Qing  , Zhang Hai-Yan  , Li Shi-Ying  , Zeng Xiang-Hua  ,   扬州大学物理科学与技术学院，扬州  225002
Published: December 2020

Based on the classical molecular dynamics method by using TLHT potential, the dynamical process of rare-gas atoms injected into single-walled carbon nanotube (SWCNT) is discussed. Firstly, the minimal diameters of SWCNT absorbing rare-gas atoms He, Ne, Ar, Kr, Xe are obtained as 6.3 ?,7.0 ?, 8.6 ?,8.6 ? and 8.6 ?, respectively. Then, the threshold energies to encapsulate the rare-gas atoms in SWCNT of different diameters are calculated. The interesting result is that the encapsulated rare-gas atoms are constantly oscillating in SWCNT, and the oscillation period bears no relation to the injection energy, while the amplitude depends on the injection energy, that is, the amplitude increases with increasing injection energy. The investigation indicates that for a suitable SWCNT, rare-gas atoms with a relative small kinetic energy will oscillate steadily in SWCNT, and the oscillation frequency can reach GHz order.
Electronic structure and property of ZnS under high pressure
Authors: Hu Yong-Jin  , Cui Lei  , Zhao Jiang  , Teng Yu-Yong  , Zeng Xiang-Hua  , Tan Ming-Qiu  ,   (1)扬州大学物理科学与技术学院，扬州 225002; (2)浙江大学物理系,杭州 310027
Published: December 2020

We have calculated the electronic structure of zinc blende structure ZnS under different high pressures by means of plane wave pseudo-potential method(PWP) with generalized gradient approximation (GGA) in this paper. We have found that the lattice constants and bond length decrease with pressure increasing. The charge transfer from S atoms to Zn atoms becomes less, and the covalence nature of Zn-S bond becomes stronger. Secondly, the peak of density of states of Zn atoms and S atoms change to some degree. Furthermore, it has a shifting tendency towards lower energy. On the other hand, ZnS turns from direct band gap to indirect band gap semiconductor when ambient pressure reaches 24GPa. The indirect band gap narrows and the direct band gap widens with pressure increasing.
The giant magneto-impedance effect and frequency dependence of magnetization processes in NiFeCoP/BeCu composite wire
Authors: Xin Hong-Liang  , Yuan Wang-Zhi  , Cheng Jin-Ke  , Lin Hong  , Ruan Jian-Zhong  , Zhao Zhen-Jie  ,   华东师范大学物理系，上海 200062
Published: December 2020

The NiFeCoP/CuBe composite wire is produced by electroless-deposition. The composite wire shows distinct magnetoimpedance effect at low frequency. The maximal GMI ratio is 40% at 20kHz and about 97% at 180kHz. The frequency dependence of magnetization in NiFeCoP composite wire is analyzed in terms of equivalent circuits and complex permeability. The relaxation frequency of the composite wire is about 1MHz. The displacement of domain wall can be damped by the DC applied field. So the effect of the DC applied field is to eliminate the parallel RL circuit.
Locating the variable message signs by cell transmission model
Authors: Shang Hua-Yan  , Huang Hai-Jun  , Gao Zi-You  ,   (1)北京航空航天大学经济管理学院，北京 100083; (2)北京交通大学交通运输学院，北京 100044
Published: December 2020

With the development of intelligent transportation technologies, the variable message signs (VMS) have been widely used in guiding and managing the dynamic traffic. It is known that cell transmission model (CTM) can well reproduce such traffic dynamics as shock waves and jams. This paper employs the CTM to study the location problem of VMS. Simulation results show that there exists an optimal VMS location to minimize the total travel time of the traffic system. How changes of route choice probabilities before and after a traffic accident affect the optimal VMS locations is also investigated and it is concluded that the VMS should be placed far from the accident site if the anticipated accident is very serious.
Subwavelength cavity resonator microstrip antennas based on left-and right-handed metamaterial bilayered substrates
Authors: Yang Rui  , Xie Yong-Jun  , Wang Peng  , Yang Tong-Min  ,   西安电子科技大学天线与微波技术国家重点实验室,西安 710071
Published: December 2020

By introducing cavity resonators to microstrip structures, subwavelength cavity resonator microstrip antennas with left- and right-handed metamaterial bilayered substrates are proposed and investigated. Due to the phase compensation, the total height of the antennas is reduced rather than increased. With certain sets of parameters, as a breakthrough to the restricted bandwidth of the conventional microstrip antennas, greatly broadened bandwidth can be achieved. Under other conditions, antennas with narrow bandwidth and resonant sensitivity can be realized. Corresponding applications for sensor use are proposed, and distinct advantages over the nonresonant electromagnetic wave sensors are demonstrated.
Study on asymmetricall epitaxial behavior of Cu-Au system by molecular dynamics simulation
Authors: Zhang Chao  , Meng Yang  , Yan Chao  , Tang Xin  , Wang Yong-Liang  , Zhang Qing-Yu  ,   大连理工大学三束材料改性国家重点实验室  大连  116024
Published: December 2020

Molecular dynamics simulation has been used to study the heteroepitaxy of Cu/Au(001) and Au/Cu(001) with the embedded atom potentials. It is found that Cu/Au(001) has a different heteroepitaxial behavior from Au/Cu(001). The epi-islands of Cu grow on Au (001) in the lattice of Au (001) without any defect. For the epitaxy of Au/Cu(001), however, mismatching dislocations can be observed in the island larger than 7×7. The asymmetricall epitaxial behavior can be attributed to the difference in the strain state and elastic properties between Cu and Au islands. With the increase of heteroepitaxial islands, the micro-misfit of Cu/Au(001) decreases monotonically, but the micro-misfit of Au/Cu(001) has an oscillating increase. The Cu epi-islands enable the substrate to be deformed at the edge of the islands while the substrate in Au/Cu(001) is deformed at the region under the islands.