bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamical stability of equilibrium of a thin elastic rod
Authors: Liu Yan-Zhu  , Xue Yun  , Chen Li-Qun  ,   (1)上海大学力学系，上海 200072; (2)上海交通大学工程力学系，上海 200030
Published: December 2020

The problem on stability of equilibrium of a thin elastic rod in view of dynamics is discussed in this paper. The dynamical equations of the rod is established, and the definitions of Lyapunov stability for a discrete dynamical system with arc-coordinate s and time t as double arguments are proposed. As an example, the stability of straight equilibrium of a rod with noncircular cross-section and intrinsic twisting is analyzed by use of the first approximation method. It was proved that the straight equilibrium of the rod is stable dynamically when the conditions of stability are satisfied within the scope of statics.
Study on the spin-polarized electronicstructures and atomic magnetic moments ofcluster La8-xBaxCuO6
Authors: Chen Li  , Li Hua  , Dong Jian-Min  , Pan Feng-Chun  , Mei Liang-Mo  ,   (1)山东大学物理与微电子学院，济南 250100; (2)山东大学物理与微电子学院，济南 250100;临沂师范学院物理系，临沂 276005
Published: December 2020

The Xα method is applied to study the spin-polarized electronic structures and atomic magnetic moments of clusters La8-xBaxCuO6 in the compound La2-yBayCuO4.This paper shows that Cu magnetic moment in La2CuO4 is 0.37μB, which is in better agreement with the experimental value(0.48±0.15μB). Ba substitution lowers the structure symmetry, removes molecular orbital degeneracy, and hence strengthens orbital hybridization and weakens quasi-two-dimensional feature, which enhance the coupling between Cu-O layer and the neighbormg layers and influence the charge transfer. These changes strongly affect the properties of carriers. Holes are introduced due to Ba substitution and they mainly enter into O sites, a few d-electronic holes enter into Cu sites, which causes important effects on the density of states, atomic magnetic moment and valence states of Cu and O in Cu-O layers. The results confirm that the holes are not always beneficial to the superconductivity. At the beginning the holes are beneficial to the superconductivity; they can decrease the superconductivity when more holes are introduced. This paper can explain that the transition temperature of high-temperature superconductive oxides changes with the variation of the doping level.
Stochastic resonance in a single-mode laser driven by the colored pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts
Authors: Cheng Qing-Hua  , Cao Li  , Wu Da-Jin  ,   (1)华中科技大学激光技术国家重点实验室，武汉 430074;湖北长江大学物理科学与技术学院，荆州 434100; (2)华中科技大学激光技术国家重点实验室，武汉 430074;中科技大学物理系，武汉 430074
Published: December 2020

We present an analytic investigation of the signal-to-noise ratio of output intensity in a loss-noise model of a single-mode laser system driven by the colored pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts. Stochastic resonance (SR) in the curve of signal-to-noise ratio R versus the pump noise self-correlation time τ,signal frequency Ω,and cross-correlation coefficient between the real and imaginary parts of the quantum noise λq are found. It extends the conclusion of the typical SR,that is, \!there is a maximum in the curve of R vs noise intensity\". Moreover,we detect that,when the parameter Ω increases,the shape of the Rτ curve will exhibit a change process of multiform SR: the curve experienced from simulta neous existence of resonances and suppressions to single-peak SR and finally to the monotonous rise. And when the parameter τincreases,the shape of theRΩcurve also exhibit a change process of multiform SR: the curve experienced from the monotonous rise to the simultaneous existence of resonances and suppressions and finally to the monotonous descending. For the Rλq curve,it appears an acute single-peak form.
Low-frequency waves in collisionless plasma current sheet
Authors: Zhou Guo-Cheng  , Cao Jin-Bin  , Wang De-Ju  , Cai Chun-Lin  ,   中国科学院空间科学与应用研究中心，北京 100080
Published: December 2020

Linear dispersion properties and waves of collisionless plasma current sheet at small scales are discussed, using 25dimensional, collisionless and incompressible magnetohydrodynamic (MHD) models with the full electron pressure tensor. General dispersion relations are very complex. Two special cases, i.e., the central region of current sheet and the electronβ*e=0, are analytically studied here. The main results are as follows. (1) In the ioninertial region (kdi>1), there are fast magnetosonic-kinetic Alfven waves and obliquely Alfven-whistler waves, and the electron magnetohydrodynamic (EMHD) model is a precise MHD model. In the long wavelength region (kdi<1), there are Alfven waves and ion acoustic waves, and the ideal MHD model is valid. (2) When electron β*e=0, the results drop off some modes, e.g., the fast magnetosonic-kinetic Alfven wave and ion acoustic wave. This case is not exactly valid for the current sheet plasma. (3) At central region of current sheet, results from both of physical models have fast magnetosonic kinetic Alfven waves.
Collisional effects on characteristics of asymmetric radio-frequency sheaths
Authors: Lu Yan  , Wang You-Nian  ,   大连理工大学物理系,大连 116024
Published: December 2020

For most reactive radio-frequency plasma etching processing, the plasma sheaths near two electrodes are asymmetric due to the powered electrode area being smaller than the grounded electrode area. Taking collisional effects of ions with neutrals in the sheaths into account, a selfconsistent dynamic model is proposed here to describe the characteristics of radio-frequency sheaths. Numerical results show the collisional effects on some physical quantities, such as instantaneous voltages on the electrodes, instantaneous thicknesses of the electron sheathes, spatial distributions of the ion density and the electric field in the sheaths, and instantaneous voltage difference between two electrodes.
The behavior of photoluminescence from SiC:Tb films deposited on porous silicon substrate
Authors: Xu Da-Yin  , Liu Yan-Ping  , He Zhi-Wei  , Fang Ze-Bo  , Liu Xue-Qin  , Wang Yin-Yue  ,   兰州大学物理科学与技术学院,兰州 730000
Published: December 2020

The SiC:Tb films were deposited on porous silicon substrate by rfsputtering. The samples prepared were annealed in N2 atmosphere at different temperatures, and Fourier transform infrared has been used to characterize the structure of them. We observed a strong photoluminescence(PL) spectrum at room temperature in the ultraviolet(UV) and visible regions. We found that the UV emission has obvious changed and a slight blue shift was observed with the change of annealing temperature. The UV and visible PLs were attributed to oxygen deficit center(ODC) and Tb3+ respectively.
The study of I-V characteristics of single-electron triple-barrier tunnel-junction
Authors: Liu Yan-Xin  , Wang Yong-Chang  , Du Shao-Yi  ,   西安交通大学理学院，西安 710049
Published: December 2020

The master equation of the single-electron triple-barrier tunnel-junction(TBTJ) model is developed based on the orthodox theory. The steady distribution of electrons on the Coulomb islands is obtained with the linear system of equations method and the I-V curves through the simulation method are presented in this paper. Discontinuities of the slope of the curve at the flat-form of Coulomb staircase compared to double barrier tunnel-junction system, which is caused by the change of the electron numbers on the second Coulomb island, are found. The system temperature requirement can be reduced in the TBTJ system, and the maximum temperature at which Coulomb staircase can be resolved is estimated using the energy spacing at the Fermi energy.
Study of 3C-SiC and 4H-SiC films deposited using RF sputtering method
Authors: Lin Hong-Feng  , Xie Er-Qing  , Ma Zi-Wei  , Zhang Jun  , Peng Ai-Hua  , He De-Yan  ,   兰州大学物理科学与技术学院，兰州 730000
Published: December 2020

SiC films were deposited on Si(111) substrates by radio-frequency (RF) sputtering method. High-resolution x-ray diffraction and infrared (IR) absorption spectroscopy were used to investigate the composition and bonding structures of the SiC films. The analysis indicated that the samples deposited at high temperatures (＞800℃) were found to consist of 4HSiC or 3CSiC crystallites, while the amorphous films were obtained at lower temperatures. IR spectra suggested that the main absorption property was caused by Si—Cb ondings. Furthermore, atomic force microscopy was used to examine the surface morphology of the SiC films and the field emission properties of the films were studied.
The interaction of excitons with phonons and solution of breathers in one-dimensional molecular chain
Authors: Xu Quan  , Tian Qiang  ,   (1)北京师范大学物理系，北京 100875; (2)大庆高等专科学校物理系，大庆 163712
Published: December 2020

By virtue of the method of continuum limit,we obtained the solitons of the vibration of lattice in one-dimensional harmonic and anharmonic molecule chains，through which the equations of exciton and phonon are solved. On considering th e cubic anharmonic potential,the vibration of lattice in one\|dimensional mole cule chain has a solution of kink soliton and on considering the quartic anharm onic potential，the vibration of lattice in one-dimensional molecule chain has a so lution of breathers.
Luminescence of Eu3+ Ions in nanocrystalline zirconia
Authors: Liu Huang-Qing  , Wang Ling-Ling  , Qin Wei-Ping  ,   (1)湖南大学应用物理系,长沙 410082; (2)中国科学院长春光学精密机械与物理研究所，中国科学院激发态开放实验室,长春 130022
Published: December 2020

Nanocrystalline zirconia doped with 1mol%Eu3+ was prepared by co-precipitation method, Its structure was characterized with x-ray diffraction(XRD), the grain size of the nanocrystals was about 10nm obtained by XRD and Scherrer' equation. The luminescence of nanosized zirconia powders doped with Eu3+ ions was investigated under 394nm excitation, the emission of 5D0→7F2 transition peaked at 604nm. Furthermore, an enhanced emission at 604nm induced by ultraviolet irradiation was observed for the nanosized zirconia powders doped with Eu3+ ions.
The groud-state wave function and evolution of the interference pattern for a Bose-condensed gas in 3D optical lattices
Authors: Xu Zhi-Jun  , Cheng Cheng  , Yang Huan-Song  , Wu Qiang  , Xiong Hong-Wei  ,   (1)杭州师范学院，杭州 310012; (2)浙江工业大学应用物理系，杭州 310014
Published: December 2020

Based on the Gross-Pitaevskii equation and by using the effective chemical poten tial,we study the distribution of the Bose-condensed gas in the combined potenti als (magnetic trap and three-dimensional optical lattices).The normalized ground-state wave function is given from the distribution of the Bose-condensed gas.The analytical expression of the density distribution of the Bose-condensed gas is given by using the propagator method when the combined potentials and only the optical lattices are switched off,respectively.When the combined potentials are switched off,the theoretical results of this work agree well with the experiment by Greiner et al.When only the optical lattices are switched off,it is show n that the interference pattern will oscillate in the magnetic trap.In addition,the evolution of the interference pattern is also investigated in the case of an isotropic magnetic trap.
Nonequilibrium statistical information theory
Authors: Xing Xiu-San  ,   北京理工大学物理系，北京 100081
Published: December 2020

In t his paper, we propose a nonequilibrium statistical information theory, whose ke rnel is information(entropy) evolution equation describing information evolution law. A nonlinear evolution equation of Shannon information (entropy) is derived . The statistical physical information is introduced and its nonlinear evolution equation is derived. Both of these two information (entropy) evolution equatio ns show that the temporal change rate of statistical information (entropy) densi t y originates together from their drift, diffusion and dissipation (production) i n coodinate space (and state variable space). The expressions of drift informati on flow and diffusion information flow, the concise formulas of statistical entr opy production rate and statistical information dissipation are given. The stati stical information dissipation (or increase) rate being equal to its statistical entropy production (or decrease) rate of the dynamic system, the information di ffusion and information dissipation occuring at the same time are proved. The d ynamic mutual information and dynamic channel capacity reflecting the dynamic di ssipative character in transmission process is presented. The similarities and dissimilarities between Shannon information (entropy),its evolution equation an d physical information (entropy),its evolution equation are discussed.
Study of a discrete chaotic system based on tangent-delay for elliptic reflecting cavity and its properties
Authors: Sheng Li-Yuan  , Sun Ke-Hui  , Li Chuan-Bing  ,   中南大学物理科学与技术学院，长沙 410083
Published: December 2020

Based on the physical model of ellipse reflecting cavity, the tangent-delay operation is proposed to change the evolution route of the systems , and a new class of discrete chaotic map systems is deduced based on the tangen t-delay operation. Simulation experiments show that the discrete chaotic systems have many special properties such as the maximum Lyapunov exponent is over zero , unchangeable equiprobability distribution and zero correlation in total field, there exists a square chaotic attractor when tangent delays one unit, and becom e ergodic state when tangent delays more units than one. The discrete chaotic sy stems can generate 2 independent pseudo-random sequences together. All of the pr operties suggest that the class of chaos systems possesses the potential applica tion in encryption.
A symbolic dynamics approach for the complexity analysis of chaotic pseudo-random sequences
Authors: Xiao Fang-Hong  , Yan Gui-Rong  , Han Yu-Hang  ,   (1)西安交通大学建筑工程与力学学院，西安 710049; (2)中国工程物理研究院，绵阳 610003
Published: December 2020

By considering a chaotic pseudo-random sequence as a symb olic sequence, we present a symbolic dynamics approach for the complexity analys is of chaotic pseudo-random sequences. The method is applied to the cases of Logistic map and one-way coupl ed map lattice to demonstrate how it works, and a comparison is made between it and the approximate entropy method. The results show that this method is app licable to distinguish the complexities of different chaotic pseudo-random seque nces, and it is superior to the approximate entropy method.
Optical absorption of nanoclusters by sequentially implanting into SiO2 glass and subsequently annealing in a selected atmosphere
Authors: Zhang Li  , Jiang Chang-Zhong  , Ren Feng  , Chen Hai-Bo  , Shi Ying  , Fu Qiang  ,   (1)武汉大学物理科学与技术学院，武汉 430072; (2)武汉大学物理科学与技术学院，武汉 430072;武汉大学电子显微镜中心，武汉 430072
Published: December 2020

Ag and Cu ions were implanted sequentially into SiO2glass by using a metal vapor vacuum arc (MEVVA) source in the room temperature. Both of the doses were 5×1016 ions/cm2The accelerated voltage for Ag was 43kV and for Cu 30kV with the ion flux density～2mA/cm2The valence states of composite sa mples were observed in details by x-ray photoelectron spectroscopy (XPS). The results showed that there were metallic Ag and Cu and CuO in the sample. The formation of alloy nanoclusters have been evidenced by selected area electron diffraction (SAED), energy dispersive xray spectra (EDS) and optical absorption spectra which fit the result of theoretical simulation well. After annealed at different temperatures for 1h in either oxidizing (air) or reducing(70%N2+30%H2 gas mixture, gas pressure 20Pa) atmosphere, the absorption peaks shifted to blue and appeared a new peak during annealing in reducing atmosphere. Applying the free electron model of metal particles, we have calculated the average size of nanoclusters annealed at different temperatures, the results showed that the size of nanoclusters increased gradually with the enhancement of temperature. AgCu alloy nanoclusters were decomposed after annealing in oxidizing atmosphere. Cu atoms migrated to the surface of the sample and are oxidized; Ag nanoclusters were formed due to low oxygensilver interaction. For the sample annealed in reducing atmosphere, the alloy decomposed to Ag and Cu nanoclusters.
Formation mechanism of interface charges in the metal-semiconductor superlattices
Authors: Li Shu-Ping  , Wang Ren-Zhi  ,   厦门大学物理学系，厦门 361005
Published: December 2020

ASA energy band calculation method. The results show that the origin of interface charge Qss is the rearrangement of valence electrons in the metal and semiconductor atomic layers at the metalsemiconductor interface. The formation mechanism of the interface charge Qss in this paper is similar to that of Tung's model of the polarization of the chemical bonds at metalsemiconductor interfaces. Both of them can account for the origin of interface charge Qss even at the monocrystalline metalsemiconductor interfaces.
Electronic band structure of ferroelectric SrBi2Nb2O9
Authors: Tang Chun-Hong  , Cai Meng-Qiu  , Yin Zhen  , Zhang Ming-Sheng  ,   (1)南京大学物理系，固体微结构实验室，材料分析中心，南京 210093; (2)南京大学物理系，固体微结构实验室，材料分析中心，南京 210093;南京工程学院基础部，南京 210013
Published: December 2020

The electronic band structures of SrBi2Nb2O.9 (SBN) in both the ferroelectric and paraelectric phases were calculated using firstprinciples method. The paraelectric phase is of an indirect band gap of 1.57eV ; whereas the ferroelectric phase is of a direct band gap of 2.23eV. The valence band maxima of both the paraelectric and ferroelectric phases are mainly contributed from O2p states; while the conduction band minima are from Nb4dand Bi6p states. When transforming from the paraelectric to the ferroelectric phases, the strong hybridization between Nb4d and O2pand BiO(2) hybridization enhance the distortion of NbO6poctahedra and reduce the total energy of the system,in favor of stabilizing the ferroelectric phase. The calculation shows that the low leak current in SBN is related to Bi6p state.
Incoherently coupled screening soliton pairs composed of spatially incoherent multimode beams
Authors: Chen Yuan-Yuan  , Wang Qi  , Shi Jie-Long  ,   上海大学理学院物理系,上海 200436
Published: December 2020

Incoherently coupled screening soliton pairs composed of spatially incoherent mu ltimode beams can be established in biased photorefractive media under steadys t ate conditions, every soliton constituent of which is not only spatially incoher ent with respect to each other, but also to itself. We study that the property o f th ese incoherently coupled soliton pairs in brightbright, darkdark configurati on s by the coherent density approach and get the intensity expression of these sol iton pairs. The propagation characteristics of coherent components that compose each soliton constituent of the coupled soliton pairs are discussed in detail.
Influence of off-waist incidence on evolution of the Gaussian beam in the nonlocal nonlinear media
Authors: Guo Qi  , Xu Chao-Bin  ,   华南师范大学信息光电子科技学院传输光学实验室,广州\ 510631
Published: December 2020

In this paper, we discuss the evolution of the offwaist incident Gaussian beam in the nonlocal nonlinear media by use of the (1+1)dimensional strongly nonlocal model. An exact analytical solution for the evolution is obtained. We find that no matter how high the power of the incident beam is, the beam width will oscillate periodically and no spatial soliton will exist, which is substantially different from the onwaist incident case. The influence of the input power and incident position on beam evolution is also discussed. The higher the input power, the narrower the beam width is. The incident position determines the initial evolution trend. The definition of a “spatial chirp” is given, to our knowledge, for the first time. The physical origin of the above phenomenon is that the different incident position corresponds to the different spatial chirp. The concept of the spatial chirp provides a new physical qualitative insight into the evolution of optical beams. The comparisons of beam evolutions in focusing media, in defocusing media and in linear homogeneous media are also given.
Dynamics of zonal flow based on resistive interchange mode turbulence
Authors: Yin Shao-Quan  , Peng Xiao-Dong  ,   (1)核工业西南物理研究院，成都 610041; (2)乐山师范学院物理系,四川乐山市 614000
Published: December 2020

Dynamics of zonal flow excitation in tokamak plasmas is investigated based on th e re sistive interchange mode turbulence. Employing lowfreedom approach, the resist i ve interchange mode turbulencezonal flow system is solved both analytically an d numerically. Our results show that the largescale zonal flow or oscillating z o nal flow can be excited in the case of sufficiently high pressure gradient (driv ing force).
Simulation study of microstructure transition of liquid metal in during solidification processes
Authors: Liu Rang-Su  , Qin Shu-Ping  , Hou Zhao-Yang  , Chen Xiao-Ying  , Liu Feng-Xiang  ,   湖南大学应用物理系，长沙 410082
Published: December 2020

A computer simulation tracking study for the rapid solidification processes of liquid metal In system has been performed by means of molecular dynamics method.U sing the index method of HoneycuttAndersen(HA)and the cluster bondtype index method,the bondtypes,clusters and cluster configurations of In atoms are anal yzed.It has been found that,contrary to conventional metals(such as Al),the rela tive number of 1551,1541 bond types,related to the icosahedral configuration,is decreased remarkably with decreasing temperature;the total number of 1421,1422 a nd 1431 bond types,related to the fcc and hcp structures,only changes a little;t he total number of 1321,1311,1301 and 1201 bond types,related to the rhombohedra l structure,increases remarkably,and then gradually plays a dominant role.Finall y,the amorphous structure is formed mainly with rhombohedral structures and mixe d up with clusters of cubic(fcc,bcc)and hcp structures.However,the icosahe dral and various polyhedra structures,which occupied a dominant position in the previous amorphous structure of metal Al,vanish completely in the present amorph ous structure of metal In.This is just the physical origin in microstructure for the obvious difference between the g(r) curves of amorphous In having a spl itting second peak with a lower front subpeak and a higher behind one,and the g(r) curves of amorphous Al having a splitting second peak with a higher fro nt subpeak and a lower behind one.
Prediction of failure time for floating gate ROM devices at low dose rate in space radiation environment
Authors: He Bao-Ping  , Guo Hong-Xia  , Gong Jian-Cheng  , Wang Gui-Zhen  , Luo Yin-Hong  , Li Yong-Hong  ,   西北核技术研究所，西安 710024
Published: December 2020

The experiments of ionizing radiation were performed on floating gate ROM device s by using 60Coγrays. The experimental aim was to examine the radi ation response at various dose rates. According to the extrapolation technique and the failu re criteria we defined,the parameter failure and function failure of devices vs. dose rate were studied. Finally, based on the function of failure timevs. doserate, the failure time of floating gate ROM device in space radiation environm ent was predicted.
Influence of Si concentration on the evolution of shape and size of self-assembled Ge islands
Authors: Deng Ning  , Chen Pei-Yi  , Li Zhi-Jian  ,   清华大学微电子研究所，北京 100084
Published: December 2020

The influence of Si concentration on the shape transition of self-assemble d SiGe islands was investigated. SiGe islands with different Si concentrations were grown by UHV/CVD. The topography and size distribution of islands were cha racterized by atomic force microscopy. The results show that the critical volum e increases with Si concentration, at which the islands change from pyramids to domes. A modified m odel was established and used to explain the influence of Si concentration on the sha pe transition by introducing the revised strain energy term depending on Si conc entration. Domeshaped as well as pyramidshaped unimodal SiGe islands were gr own under suitable conditions. This research indicates that the shape and size o f the selfassembled ialnds can be controlled more accurately by adjusting Si c oncentration.
Stochastic resonance of an Ising spin system driven by stochastic external field
Authors: Shao Yuan-Zhi  , Zhong Wei-Rong  , Lin Guang-Ming  , Li Jian-Can  ,   中山大学物理系，广州 510275
Published: December 2020

The study on interesting stochastic resonance of the Ising spin system (ISS), subject to a joint external field of weak sinusoidal modulation and stochastic white noise, was carried out through solving the meanfield equation of motion ba sed on Glauber dynamics, and some new features in the dynamic response and stochasti c resonance of the above ISS were also revealed. The periodic ally driven stochastic ISS shows the occurrence of characteristic nonequilibrium d y namic phase transition when the frequency and amplitude of driving field, the te mperature of system and noise intensity attain a specific accordance in quantity . Somewhat similar to the situation in sole sinusoidal field, our primary result indicates that the dynamic transition of ISS in an applying stochastic fieldre tains probably the feature of both discontinuous transition at low temperatures and continuous transition at high temperatures. The analysis was made concerning the nonequilibrium dynamic transition induced in the Ising spin system by exter nal stochastic force in detail.
Nonequilibrium dynamic phase transition of an Ising spin system driven by various oscillating field
Authors: Shao Yuan-Zhi  , Zhong Wei-Rong  , Lin Guang-Ming  ,   中山大学理工学院物理系，广州 510275
Published: December 2020

We have studied both the dynamic response and the relevant nonequilibrium dynami cal p hase transition of an Ising spin system subject to three sorts of oscillating fi eld i.e. sinusoidal, square and sawtooth waves. The above three sorts of externa l field drive dynamically the Ising spin system in either simply gradual ( abrupt) way or their combination respectively. In the case of both sinusoidal and squar e ways, it was observed that the Ising spin system displays a low_temperature sy mmetr y-breaking ordered phase and a high_temperature symmetric disordered phase as well as the dynamic transition between two dynamical phases above. We also detected the tri_critical point separating high_temperature continuous dynamic transition and low_temperature discontinuous one on the boundary of dynamic transition. The trend of dynamic transition boundary and the dependence of tri_critical point upon the system temperature, the frequency and amplitude of the driving field we re revea led as well. In contrast, nodynamic transition occurs any longer and the system always stays in symmetry-breaking ordered state if the external field takes the form of sawtooth wave. The preceding discrepancy in dynamic response and transi tion is attributed to the perturbative characteristic of different oscillating f ields.
Giant magnetostriction of melt-spun Fe85Ga15ribbons
Authors: Liu Guo-Dong  , Li Yang-Xian  , Hu Hai-Ning  , Qu Jing-Ping  , Liu Zhu-Hong  , Dai Xue-Fang  , Zhang Ming  , Cui Yu-Ting  , Chen Jing-Lan  , Wu Guang-Heng  ,   (1)河北工业大学材料学院，天津 300130; (2)河北工业大学材料学院，天津 300130;中国科学院物理研究所磁学国家重点实验室，北京 100080; (3)中国科学院物理研究所磁学国家重点实验室，北京 100080
Published: December 2020

Large magnetostrictions of -1300 and +1100 ppm have been obtained in our Fe85Ga15ribbon samples. This was attributed to the shape anisotropy of ri bbon and the existence of Ga atom clusters with preferential orientation in the melt-spun Fe85Ga15 alloys. A small increase of magnetostriction with increasing temperature w as observed between 163 and 321K. However, at higher temperatures, the magnetost riction increases sharply with increasing temperature.
Dielectric and ferroelectric properties of BaBi4Ti4O15 ceramics and their dependence on lattice structure
Authors: Li Zheng-Fa  , Zhong Wei-Lie  , Qiu Zhong-Ping  , Ge Hong-Liang  , Zhang Pei-Lin  , Wang Chun-Lei  ,   (1)山东大学物理与微电子学院，晶体材料国家重点实验室，济南 250100; (2)中国计量学院应用物理系，杭州 310018
Published: December 2020

Good quality barium bismuth titanate (BaBi4Ti4O15) ceramics is fabric ated successfully with BaBi4Ti4O15 nanopowders prepared by Sol-Gel p rocess. The ferroelectric to paraelectric phase transition of barium bismuth titanate ceram ics was studied by determining the dielectric and saturated ferroelectric proper ties of barium bismuth titanate. All measurements show barium bismuth titanate m ay be a kind of order_disordered relaxor ferroelectrics with a diffused phase transition which is a firstordered one, and its dielectric and saturated fe rroelectric properties depended strongly on its lattice structure.
The design of visible light stealth material
Authors: Xu Wen-Lan  , Zhang Shuan-Qin  , Xu Yi  ,   (1)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; (2)总装工程兵科研一所，无锡 214035
Published: December 2020

The coarse particles theory, the fine particles theory and the bridge theory w ere used to calculate the absorption and scattering coefficients of the particle s separately according to their size compared with the light wavelength. The dif fuse reflectivity of the coating with the particles was obtained. The influences of the various parameters of the coating, such as the optical constants of the particles and the binder, the size and the volume fraction of the particles, on the diffuse reflectivity were discussed. Taking TiO2 as the example, the compu ter design method of visible light stealth coating is introduced.
A new method to construct solutions to nonlinear wave equations
Authors: Fu Zun-Tao  , Liu Shi-Kuo  , Liu Shi-Da  ,   北京大学物理学院，北京 100871
Published: December 2020

From the definition of Legendre elliptic integration and Jacobi elliptic function, new transformations are obtained and applied to construct the exact solutions of nonlinear wave equations. The nonlinear Klein-Gordon equation, Boussinesq equation and the coupled mKdV equations are taken as three examples to illustrate the detailed steps in obtaining exact solutions. There new analytical solutions such as periodic solutions and soliton solutions are derived for these nonlinear evolution equation (or equations).
Effective ABCD formulation of the propagation of the atom laser
Authors: Yin Jian-Ling  , Liu Cheng-Yi  , Yang You-Yuan  , Liu Jiang  , Fan Guang-Han  ,   (1)华南师范大学激光运动医学实验室,广州 510631;华南师范大学信息光电子科技学院，广州 510631; (2)华南师范大学激光运动医学实验室,广州 510631;香港教育学院科学系，香港; (3)华南师范大学信息光电子科技学院，广州 510631; (4)香港教育学院科学系，香港
Published: December 2020

Within the frame of the ABCD formulation for the propagators in a time-dependent quantum system, the ABCD law has been extended to the so-called effective ABCD system in which the effective beam quality factor is conservative. We discussed the system as the propagation of the atom laser beam. The effective beam quality factor and the effective parameter are introduced to obtain the effective ABCD formulation of the propagators by means of Heisenberg picture. The atom-atom interactions in the atom laser beam make the beam quality factor nonconservative, and thus the effective beam quality factor can describe the combined effect of the beam quality factor and the atom-atom interaction.
A transition from conservative to quasi-dissipative
Authors: Jiang Yu-Mei  , Lu Yun-Qing  , He Da-Ren  ,   (1)扬州大学物理科学与技术学院，扬州 225002; (2)中国科学院合肥等离子体物理研究所，合肥 230031;扬州大学物理科学与技术学院，扬州 225002
Published: December 2020

A special kicked rotor moving in a piecewise continuous force field is suggested and studied. When adjusting a control parameter,the rotor displays a transition from conservative to quasi-dissipative, and a change of a stochastic web formed by the set of the images of the discontinuous borderlines to a transient stochastic web. This transition and change can be described by a logarithmic rule of the fractal dimension of the transient stochastic web versus the control parameter, or a rule of the averaged lifetime of the iterations in the transient stochastic web versus the control parameter.
A parametric study of R—M transition laser and recombination laser in strontium ions
Authors: Pan Bai-Liang  , Chen Kun  , Chen Gang  , Yao Zhi-Xin  ,   浙江大学物理系,杭州 310027
Published: December 2020

A systematic investigation was made for the R—M transition and recombination lasers in strontium ions by the longitudinal pulse discharge-excited with the helium buffer gas in a quartz discharge tube of 9mm inner diameter and 42cm electrode's separation. The laser power of each-line as a function of different working parameters,as well as the corresponding photo-electrical pulse waveforms were analyzed and observed for two kinds of optical cavity. A set of better operating parameters was also obtained for the multi-line strontium ion laser.
Localized orthogonal function model of elliptical-hole photonic crystal fibers
Authors: Ren Guo-Bin  , Wang Zhi  , Lou Shu-Qin  , Jian Shui-Sheng  ,   北京交通大学光波所，北京 100044
Published: December 2020

A novel model for light propagation in elliptical-hole photonic crystal fibers (PCFs) is developed in terms of orthogonal function model. A new method for constructing supercell lattice is proposed; with this method the transverse index profile is decomposed into two periodic structures, and the mode field is decomposed using Hermite-Gaussian functions. The propagation constant and the mode field distribution of the PCF can be calculated by recasting the Maxwell equations into on eigenvalue system. With this model, the mode properties including dispersion properties, polarization properties and mode area can be analyzed for circular or elliptical hole PCF.
Assembly prestress and its variation in different water depths when applied to the active elements of a flextensional transducer
Authors: He Xi-Ping  , Li Bin  ,   (1)陕西师范大学物理与信息技术学院，西安 710062;西安交通大学机械与结构强度国家重点实验室，西安 710049; (2)西北工业大学航海工程学院，西安 710072
Published: December 2020

It is very important for underwater flextensional transducers to accurately control the prestress applied to the active element in assembling and working process, especially, for the rare-earth magnetostrictive flextensional transducer, to be investigated clearly the relationship between the working in different water depths and the compressive prestress applied to the active element,which will be conducive to employ the active element potential energy. On coordination with the author's research project, the assembly displacement of an underwater flextensional transducer, by which is applied prestress to the active element, is calculated with the finite element method, and an elementary experiment is performed with a class VII flextensional transducer. The magnitudes of compressive prestress is variable when working in different water depths, the relationship is calculated by using finite element method(FEM).The method used in this paper may be generalized to other kinds of flextensional transducer.
Preparation of titanium nitride films by pulsed high-energy-density plasma and investigation of the tribological behavior of the film
Authors: Liu Yuan-Fu  , Zhang Gu-Ling  , Wang Jiu-Li  , Liu Chi-Zi  , Yang Si-Ze  ,   中国科学院物理研究所，北京 100080
Published: December 2020

Supper hard and wear resistant titanium nitride films were deposited onto 0.45% carbon steel substrate by pulsed high-energy-density plasma(PHEDP) technique at ambient temperature. The microstructure, surface compositions and depth profile of the film were analyzed by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM).The hardness profile and tribological behavior of the film were determined with nano-indenter and MM200 wear tester, respectively. The results showed that the microstructure of the film was dense and uniform and mainly composed of titanium nitride phases. A wide mixing interface existed between the film and the substrate. The film possessed a very high value of nanohardness. The wear resistance of the film was excellent and the value of the friction coefficient of the film was low under dry sliding wear test conditions.
Carbon nanotubes reinforced nickel-phosphorus base composite coating
Authors: Chen Chuan-Sheng  , Chen Xiao-Hua  , Li Xue-Qian  , Zhang Gang  , Yi Guo-Jun  , Zhang Hua  , Hu Jing  ,   湖南大学材料科学与工程学院,长沙 410082
Published: December 2020

After being modified and dispersed uniformly in solution, the Ni-P-carbon nanotube composite coatings are prepared by chemical deposition. The surface morphologies of composite coatings are analyzed with a scanning electron microscope and the tribological properties of composite coatings are investigated. The results indicated that the addition of carbon nanotubes increased the microhardness and improved mechanical properties of the Ni-P composite coating significantly. Carbon nanotubes composite coatings exhibited lower friction coefficient and high wear resistance in comparison with Ni-P-SiC composite coatings.
The dependence of single event upset cross-section on incident angle
Authors: Zhang Qing-Xiang  , Hou Ming-Dong  , Liu Jie  , Wang Zhi-Guang  , Jin Yun-Fan  , Zhu Zhi-Yong  , Sun You-Mei  ,   (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;中国科学院空间科学与应用研究中心,北京 100080
Published: December 2020

Swift heavy ions delivered by Heavy Ion Research Facility at Lanzhou(HIRFL) were used to bombard the 32k SRAM IDT71256 at angles from 0°—85°. The multiple bit upset(MBU) ratio can reach as high as 70% when the device was tested with 15.14MeV/u 136Xe ions or at large angles with 36Ar ions. The angular effect of cross section is mainly due to occurrence of MBU especially at large angles. The MBU ratio is determined by the energy deposited in the whole sensitive layer and that of more than two bit upset is increased with incident angle.
Aluminum-induced rapid crystallization of a-Si films at low temperatures in an electric field and microstructure analyses of the crystallized films
Authors: Chen Yi-Kuang  , Lin Kui-Xun  , Luo Zhi  , Liang Rui-Sheng  , Zhou Fu-Fang  ,   汕头大学物理系,汕头 515063
Published: December 2020

Aluminum-induced crystallization of amorphouse silicon (a-Si) is a suitable method for preparation of polycrystalline silicon (poly-Si) films. Biasing an electric field, which is perpendicular to the surface of the a-Si films, will accelerate the mutual diffusion of Al atoms and Si atoms in the interface during the aluminum-induced crystallization process and enhance the crystallization of the a-Si films obviously. The experimental results show that under the action of the electric field, more than 60% of a-Si transfer into poly-Si when the a-Si film was annealed at Ta＝400℃ and annealing time ta=60min; the a-Si films have obviously crystallized at Ta＝450℃ and ta=30min; at Ta＝500℃ and ta=15min, the XRD intensity of crystalline silicon (c-Si) components in the films is thrice to fourfold as strong as that in the films without the effect of an electric field.
Investigation of magnetization change in GdFeCo/DyFeCo exchange-coupled films
Authors: Zhang Yue-Pin  , Wang Xian-Ying  , Lin Geng-Qi  , Li Zhen  , Li Zuo-Yi  , Shen De-Fang  , Gan Fu-Xi  ,   (1)华中科技大学电子科学与技术系，武汉 430074; (2)中国科学院上海光学精密机械研究所，上海 201800; (3)中国科学院上海光学精密机械研究所，上海 201800;宁波大学光电子功能材料研究所，宁波 315211
Published: December 2020

The exchange-coupled films (GdFeCo/DyFeCo) were prepared by sputtering method. The magnetization transitions caused by temperature changes had heen investigated for the films.The results indicate that the magnetization direction of the readout layer changes from in-plane to perpendicular when temperature increases.The transition occurs mainly as a result of the changes in the saturation magnetization. When the temperature increase to near the compensation temperature, the saturation magnetization and the demagnetizing energy of the GdFeCo layer decrease, With the exchange-coupled interaction,the magnetization direction of the readout layer changes.The films can be used for center aperture detection type magnetically induced super resolution.
Energy transfer between two continuous channels in photonic crystals
Authors: Feng Zhi-Fang  , Wang Yi-Quan  , Xu Xing-Sheng  , Jiang Shao-Lin  , Hao Wei  , Cheng  Bing-Ying  , Zhang Dao-Zhong  ,   (1)北京工业大学应用数理学院凝聚态物理，北京 100022; (2)中国科学院物理研究所凝聚态物理中心光物理实验室，北京 100080
Published: December 2020

In this letter energy transfer between continuous channels is analysed both theoretically and experimentally. Energy transference has been realized by changing the parameters of combined wave-guides. In the experiment, we have also measured the transmission spectrum.
Upconversion luminescence and Spectra characteristics of Er3+, Tm3+ co-doped NaY(WO4)2 crystal
Authors: Tan Hao  , Song Feng  , Su Jing  , Shang Mei-Ru  , Fu Bo  , Zhang Guang-Yin  , Cheng Zhen-Xiang  , Chen Huan-Chu  ,   (1)南开大学光子学中心，天津 300071; (2)山东大学晶体研究所，济南 250100
Published: December 2020

Absorption spectra, emission spectra, excitation spectra, and upconversion luminescence of Er3+, Tm3+ co-doped NaY(WO4)2 crystal were measured at room temperature. Intensity parameters are calculated from absorption spectra in terms of Judd-Offelt theory. Transition processes of the energy levels of Er3+ and Tm3+ were analyzed in details and the cross relaxations: 1G4(Tm3+)＋4I15/2(Er3+)→3F4(Tm3+) +4F9/2(Er3+) ,1G4(Tm3+)＋4I15/2(Er3+)→3H5(Tm3+)＋4I9/2(Er3+), 3F4(Tm3+)＋4I9/2(Er3+)→3H6(Tm3+)＋4S3/2 or 2H11/2(Er3+) and 4F9/2(Er3+)＋3H6(Tm3+)→4I15/2(Er3+)+3F3(Tm3+) were put forward. Sufficient proofs have been found to illustrate the use of Er3+ as a sensitizer which is effective for the Tm3+-doped crystal.
Polarization holographic image storage with indolylfulgimide
Authors: Wang Ying-Li  , Yao Bao-Li  , Chen Yi  , Fan Mei-Gong  , Zheng Yuan  , Menke Nei-Mu-Le  , Lei Ming  , Chen Guo-Fu  , Han Yong  , Yan Qi-Qiang  , Meng Xian-Juan  ,   (1)中国科学院物理化学技术研究所，北京 100101; (2)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

Co-polarized and cross-polarized holographic gratings were respectively recorded on the indolylfulgimide/PMMA film and their diffracted images were obtained. The experiment indicates that the indolylfulgimide possesses the characteristic of photo-induced anisotropy, therefore it can be used for cross-polarized holographic recording. In polarization holography, the polarization of diffraction beam is dependent on the polarizations of reference beam and object beam. The noise of the diffraction image mainly comes from the diffusion of the readout beam on the sample. Cross-polarized holography can obtain higher signal-to-noise ratio of reconstructed image than that of co-polarized holography. Holographic gratings recorded on the film can be kept for at least five months in darkness at room temperature without decrease of diffraction efficiency. The results show that indolylfulgimide is an erase-rewritable optical storage material that can be used in polarization holography.
The minimum optical wavepackets
Authors: Deng Wen-Ji  , Xu Ji-Huan  , Liu Ping  ,   (1)华南理工大学材料科学研究所,广州 510640; (2)华南理工大学物理系,广州 510640
Published: December 2020

The explicit expressions of minimum classical wavepackets are generally derived by using the operator technique of quantum mechanics.The problem of optical wavepackets travelling in vacuum is taken as an example to investigate the meaning of complex functions and negative frequency in classical physics.The central frequency of complex Gaussian wavepackets can be freely adjusted through the displacement parameter and squeeze factor. Some other characters of the minimum optical wavepackets are also studied.
A DCT domain quadratic predictor for real-time prediction of continuous chaotic signals
Authors: Zhang Jia-Shu  , Li Heng-Chao  , Xiao Xian-Ci  ,   (1)电子科技大学电子工程学院,成都 610054; (2)西南交通大学信号与信息处理四川省重点实验室,成都 610031
Published: December 2020

A DCT domain quadratic predictor with normalized least mean square (NLMS) algorithm, efficient implementing structure of the reduced parameter second-order Vloterra filter (RPSOVF), is proposed to investigate nonlinear real-time multi-step prediction performance of three kinds of continuous chaotic signals. Experimental results show that the real-time ahead one-step prediction mean square errors of the DCT domain quadratic predictor proposed in this paper are at least 100 times smaller than that of RPSOVF, which indicates that this predictor has better predictive performance, its structure is simple and easy to implement. Multi-step prediction performance of this DCT domain quadratic predictor to three continuous chaotic time series is superior to the one of local prediction method obviously, and its mean square errors do not increase exponentially according as the prediction step.
Effect of nucleon momentum distribution on the calculation of semiclassical distorted wave model
Authors: Hu Ze-Hua  , Sun Wei-Li  , Zhang Ben-Ai  , Tian Dong-Feng  ,   (1)北京应用物理与计算数学研究所,北京 100088; (2)中国工程物理研究院北京研究生部,北京 100088
Published: December 2020

The semiclassical distorted wave(SCDW)model is applied to the analysis of the multistep direct processes of 90Zr(p,p′x) at 80 and 160MeV incident energies with the single particle momentum distribution of target nucleons given by the coherent density fluctuation model. The calculated double differential cross sections are compared with the experimental data and the results of the previous SCDW model calculations. The agreement of the calculated double differential cross sections with the experimental data is improved, compared with the previous calculations. The effect of the momentum distribution of target nucleons on the calculated cross sections is discussed.
Study on hyperspectral detection system with the harmonic diffractive element in infrared dual-band
Authors: Sun Qiang  , Yu Bin  , Wang Zhao-Qi  , Mu Guo-Guang  , Lu Zhen-Wu  ,   (1)南开大学现代光学研究所，光电信息技术科学国家教育部重点实验室,天津 300071; (2)中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,长春 130022; (3)中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,长春 130022;南开大学现代光学研究所，光电信息技术科学国家教育部重点实验室,天津 300071
Published: December 2020

In this paper, the application of harmonic diffractive element（HDE） in the infrared hyperspectral detection system is investigated based on the special large dispersion capability of HDE and window character of infrared bands. The fundamental principle of the new infrared hyperspectral imaging is described, and a design sample is presented. It is shown that the resolution is improved and the optical power received is enlarged. The rectification of the ray aberrations in both band has been simultaneously accomplished. Wave front aberrations are less than 1/4 wavelength,and the modulation transfer function of the dual-band in every zoom focus location approaches or attains the diffraction limit of 20 cycles/mm.
Interaction between photovotaic spatial solitons with difference wavelengths
Authors: Ouyang Shi-Gen  , Wang Xiao-Sheng  , She Wei-Long  ,   中山大学光电材料与技术国家重点实验室，广州 510275
Published: December 2020

The interaction between photovoltaic spatial solitons with difference wavelengths in photovoltaic-photorefractive crystals is investigated by numerical method. Our numerical study indicates that the interaction between these solitons is inelastic, and these solitons keep their shapes only within some propagation distance. Besides the attraction with each other, the energy of soliton would be coupled from one waveguide to other waveguide during propagation.
A JEC-FDTD implementation for anisotropic magnetized plasmas
Authors: Liu Shao-Bin  , Mo Jin-Jun  , Yuan Nai-Chang  ,   (1)国防科技大学电子科学与工程学院,长沙 410073; (2)国防科技大学电子科学与工程学院,长沙 410073;南昌大学物理系,南昌 330047
Published: December 2020

A JEC finite-difference time-domain (JEC-FDTD) methodology for dispersive media is extended to anisotropic magnetized plasmas. The problem which incorporates both anisotropy and frequency dispersion at the same time is solved for the electromagnetic wave propagation. The JEC-FDTD formulation for anisotropic magnetized plasmas is derived. The high efficiency and accuracy of the method are confirmed by computing the reflection and transmission through a magnetized plasma layer, with the direction of the propagation parallel to the direction of the biasing field. A comparison with frequency-domain analytic results is included.