bluuebunny/crossref_metadata_2025 huggingface dataset:
Photon avalanche upconversion in TiO2∶Mo
Authors: Wu Chang-Feng  , Qin Wei-Ping  , Qin Guan-Shi  , Huang Shi-Hua  , Zhang Ji-Sen  , Zhao Dan  , Lü Shao-Zhe  , Lin Hai-Yan  , Liu Huang-Qing  ,   中国科学院激发态物理重点实验室,中国科学院长春光学精密机械与物理研究所,长春  130021
Published: December 2020

The Mo-doped titania exhibits a visible broadband emission under a 978 nm laser diode excitation. The luminescence has been assigned to the transitions from the excited states 3T1, 3T2 to the ground state 1A1 of the ［MoO4］2- radical. In TiO2∶Mo system, the p ower dependence of the upconversion-luminescence intensity exceeds a quadratic dependence, and the time evolution of the upconversion luminescence after the onset of continuous wave excitation is characterized by a rise time of 63 ms. These properties show the typical fingerprints of a photon avalanche. No luminescence was observed from the sample when excited with a pulsed laser (1064 nm) from a Nd∶YAG or a pulsed Raman-shift laser (953.6nm) pumped by a second harmonic of the Nd∶YAG. Regardless of the energy mismatch between the pulsed laser and the continuous wave diode laser, another reason may be that the duration time of a single laser pulse (10 ns) is much shorter than the rise time of the photon avalanche. The fluorescence “transfer function” theory is used to study the luminescence dynamics, which provides a good description of the experimental data.
Global stability of bidirectional associative memory neural networks with dela ys
Authors: Zhang Qiang  , Gao Lin  , Wang Chao  , Xu Jin  ,   (1)华中科技大学控制科学与工程系，武汉  430074; (2)西安电子科技大学电子工程研究所，西安  710071
Published: December 2020

The stability of the equilibrium point of bidirectional associative memory (BAM) neural networks with delays is studied by constructing a suitable Lyapunov functional and combining with some inequality analysis techniques- On the assumption that the activation functions of neurons are less restrictive than those in t he literature (which may not satisfy Lipschitz condition), a new sufficient cond ition ensuring the global asymptotic stability of BAM neural networks with delay s is derived- The results presented here can be applied to the design of a wider class of neural networks including non-Lipschitz activation functions of neuron s-
A study of the bifurcation effect of closed orbits on the recurrence spectra of Li Rydberg atoms in an external electric field
Authors: Song Xiao-Hong  , Lin Sheng-Lu  ,   山东师范大学物理系，济南  250014
Published: December 2020

The semiclassical closed-orbit theory begins to fail when the returning wave bec omes infinite near the core, and this is the typical situation when bifurcations of closed-orbits occur- We describe the phenomena of bifurcations and calculate the recurrence spectra of Li Rydberg atoms in the vicinity of the bifurcation e nergy using the uniform approximation method- The spectra with a constant energy ε=-2-94, and a constant scaled electric field 135-86-1/4<160 -11 are recorded and the effect of the core-scattering is taken into account- T he recurrence spectra are compared with those obtained by the primary extended c losed-orbit theory and those of hydrogen atoms- The results display the importan t contributions of bifurcations and core-scattering to the recurrence spectra of Li Rydberg atoms-
Filamentation instability of intense laser in partially ionized plasma
Authors: Zhang Jia-Tai  , Liu Song-Fen  , Hu Bei-Lai  ,   (1)北京应用物理与计算数学研究所，计算物理国家重点实验室，北京  100088; (2)南开大学物理学院,天津  300071
Published: December 2020

The difference between fully ionized and partially ionized plasmas lies in the presence of bound electrons. From this difference the propagation of intense laser pulse and the refraction index in a partially ionized plasma are analyzed. An atomic filamentation instability (AFI) can be significantly enhanced by bound electrons. The AFI in Au plasma-produced 0.35 and 0.53 μm wavelength laser light to irradiate golden target are analyzed and calculated. The results show that the growth rate of the AFI is substantially higher than that of the relativistic filamentation instability.
Propagation of x-ray in the laser plasma and its effect in the diagnosis of elec tric density
Authors: Fu Xi-Quan  , Guo Hong  ,   (1)华南师范大学传输光学实验室,广州  510631; (2)华南师范大学传输光学实验室,广州  510631;湖南大学计算机与通信学院，长沙  410082
Published: December 2020

In this paper, by introducing an error estimate parameter η and analyzing the magnitude of each term of the propagation equation, the propagation equation s of amplitude and phase of x-rays can be obtained in the laser-produced plasma. It is found that the change of phase is only dependent on the electron density , and the change of amplitude is directly dependent on phase. Moreover, only if η<1, by using iterative approximation, the approximate solutions of phase and amplitude can be obtained. Finally, by computer simulation these solutions a re confirmed.
Nonlinear threshold of two-dimensional Rayleigh-Taylor growth for incompressible liquid
Authors: Wu Jun-Feng  , ]Ye Wen-Hua  , Zhang Wei-Yan  , He Xian-Tu  ,   (1)北京应用物理与计算数学研究所，北京  100088; (2)浙江大学物理系,杭州  310028;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研究生部，北京  100088
Published: December 2020

Nonlinear threshold of two-dimensional Rayleigh-Taylor(RT) instability is analyzed in planar and cylindrical and spherical geometries. Density amplitude is defined relating to instable interface and formulas of nonlinear threshold values for RT instability in three kinds of geometries are given, then high-order algorithm is used to simulate two-dimensional RT instability in these geometries, and t he simulation results agree well with the formulas.
Phonon spectrum of single-walled carbon nanotubes
Authors: Xiao Yang  , Yan Xiao-Hong  , Cao Jue-Xian  , Ding Jian-Wen  ,   (1)湘潭大学材料与光电物理学院，湘潭  411105; (2)湘潭大学材料与光电物理学院，湘潭  411105;湘潭大学力学与材料工程研究所，湘潭  411105
Published: December 2020

The phonon spectra are calculated within the frame of force constant model. By virtue of five rotation operations determined by the coordinates of carbon atoms, it is convenient for us to obtain the force matrix. The calculations show that there are only 12 non-degenerate phonon branches and 6(n-1) degenerate branc hes for armchair (n, n) tube and zigzag (n, 0) tube.
Thermodynamic calculation of the oriented internal stress in single crystals of Ni52Mn24Ga24
Authors: Cui Yu-Ting  , Liu Zhu-Hong  , Wang Wen-Hong  , Zhang Ming  , Chen Jing-Lan  , Wang Wan-Lu  , Wu Guang-Heng  , Meng Fan-Bin  , Qu Jing-Ping  , Li Yang-Xian  ,   (1)河北工业大学磁性材料与技术中心，天津  300130; (2)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;重庆大学应用物理系，重庆  400044; (4)重庆大学应用物理系，重庆  400044
Published: December 2020

The internal stress in single crystals of Ni52Mn24Ga2 4 has been calculated based on the balance equation and the experimental data on transformation strains with or without bias field. It was found that the residual oriented internal stress caused by the directional solidification during the crystal growth plays an important role in achieving the reorientation of the variants, and resulting in a large transformation strain.Furthermore, according to Maxwell equation and Ullako's thermal dynamic model, the theoretical value of magnetic-field-induced strains and internal stress at different temperatures in martensite was calculated based on a best fitting of the strain curves versus the bias field. Compared with the experimental observation, the availability of various models has been discussed.
Influnce of Al-content on the property of the two-dimensional electron gases in AlxGa1-xN/GaN heterostructures
Authors: Kong Yue-Chan  , Zheng You-Dou  , Chu Rong-Ming  , Gu Shu-Lin  ,   南京大学物理系，南京  210093
Published: December 2020

By self-consistently sovling the coupled Schrdinger and Poisson equations, we have investingated the property of the two-dimensional electron gases (2DEG) in AlxGa1-xN/GaN heterostructures. We demonstrate the depen dence of the density, the distribution, and the subband occupation of the 2DEG on the Al-content of the AlGaN barrier. Band offset and mechanism of spontaneous and piezoelectric polarization were concerned to discuss our results.
SFM investigation of nanoscale domain structure in ferroelectric PZT thin films
Authors: Zeng Hua-Rong  , Li Guo-Rong  , Yin Qing-Rui  , Tang Xin-Gui  ,   中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室,上海  200050
Published: December 2020

Nanoscale domain structures and polarization reversal behaviour in (111)-oriented PZT60/40 thin film were investigated in-situ with scanning force microscopy p iezoresponse mode. Complex domain contrast is related to the arrangement of doma ins in grains and to the orientation of the grains in the film. The step structu re of ～ 30 nm in width was directly observed, which was formed during the polar ization reversal process. The presence of the step structures reveals that the f orward domain growth mechanism prevails in the polarization switching process of PZT60/40 thin films.
Effect of grid and bias on the characteristic of CHF3 electron cyclot ron resonance discharge plasma
Authors: Ye Chao  , Du Wei  , Ning Zhao-Yuan  , Cheng Shan-Hua  ,   苏州大学物理系,苏州  215006
Published: December 2020

The characteristics of CHF3 electron cyclotron resonance(ECR) plasma, which is formed in the case of a floating grid in an ECR-chemical vapor deposition system and +60V or -60V biased at grid, were investigated by an actinometric optical emission spectroscopy. It is found that the effects of grid and biasing on the distribution of radicals occur mainly at a low microwave input power. It is considered that the distribution of radicals at a low power is controlled by ele ctron collision and sheath potential together due to low electron temperature. H owever, the effect of sheath potential at a high power decreases due to increasi ng electron temperature. As a result, the distribution of radicals at a high pow er is dominated by electron collision.
A conservation theorem of Hojman for systems of generalized classical mechanics
Authors: Zhang Yi  ,   苏州科技学院土木工程系，苏州  215011
Published: December 2020

The conservation theorem and the symmetries for systems of generalized classical mechanics are studied. In terms of the invariance of the ordinary differential equations under the infinitesimal transformations, this paper established the Li e symmetrical transformations of the systems in the high-dimensional extended ph ase space, which only depend on the canonical variables, and a new type of conse rvation laws are directly obtained from the Lie symmetries of the systems. Actua lly, the conservation laws are the generalization of a conservation theorem of H ojman to generalized classical mechanics. Finally, an example is given to illust rate the application of the results.
LamDe＇ function and perturbation method to nonlinear evolution equations
Authors: Liu Shi-Kuo  , Fu Zun-Tao  , Wang Zhang-Gui  , Liu Shi-Da  ,   (1)北京大学物理学院，北京  100871; (2)国家海洋局海洋环境预报中心,北京  100081
Published: December 2020

The perturbation method is applied to the multi-order exact solutions of nonline ar evolution equations. The exact solutions to the zeroth-order equation can be derived by Jacobi elliptic function expansion method, and then the first-order a nd the second-order equations can be rewritten as the homogeneous Lam equa tion and inhomogeneous Lam equation, respectively. They can be solved by using Lam functions and the Jacobi elliptic function expansion method. Thus, the mu lti-order solutions are obtained to the nonlinear evolution equations.
LamDe＇ function and invariants of multi-order exact solutions among nonline ar evolution equations
Authors: Liu Shi-Kuo  , Chen Hua  , Fu Zun-Tao  , Liu Shi-Da  ,   北京大学物理学院，北京  100871
Published: December 2020

Applying the perturbation method, the nonlinear evolution equations are expanded as multi-order approximate equations. And based on Lam equation and Lam function, these multi-order approximate equations can be solved by Jacobi elliptic function expansion method, where multi-order exact solutions of nonlinear evol ution equations are derived. Then the invariants of the multi-order exact soluti ons are found among different nonlinear evolution equations.
Bidirectional solitary wave solutions and soliton solutions for two nonlinear ev olution equations
Authors: Xu Gui-Qiong  , Li Zhi-Bin  ,   (1)华东师范大学计算机科学技术系,上海  200062; (2)上海大学信息管理系,上海  200436;华东师范大学计算机科学技术系,上海  200062
Published: December 2020

The homogeneous balance method for constructing solitary wave solutions and soliton solutions is further developed on obtaining quasi-solution by using step-by- step principle.The main advantage of the extended approach is to avoid the probl em of “intermediate expression swell”.The effectiveness of the method is demon strated by application to the generalized Boussinesq equation and the bidirectio nal Kaup-Kupershmidt equation.The one-soliton,two-soliton and three-soliton solutions with multipe collisions are derived for these two equations with the assistance of Maple.
Signature inversion in odd-odd nuclei in the mass region A=100
Authors: Luo Xiang-Dong  , Zheng Ren-Rong  , Zhu Shun-Quan  ,   上海师范大学物理系，上海  200234
Published: December 2020

With the model of an axially symmetric rotor plus two quasi-particles, the signature inversion (SI) in two odd-odd nuclei 102Rh and 98Rh in the mass region A=100 is studied. The calculated result shows that the possible SI mechanism, which has been confirmed by the calculation of odd-od d nuclei in the A=160 and A=80 regions (i e, the competition between the n-p interaction and the coriolis force in low K space) is also appropriate for odd-odd nuclei in the A=100 region. This seems to indicate that there mi ght be a universal mechanism of SI in odd-odd nuclei for different mass regions.
H+5 cluster ion and its neutral products H3 and H4
Authors: Yang Bai-Ｆang  , Miao Jing-Ｗei  , Yang Chao-Ｗen  , Shi Mian-Ｇong  ,   四川大学辐射物理及技术教育部重点实验室，原子核科学技术研究所，成都  610064
Published: December 2020

The experimental results for H+5 cluster ions are reported . The formation an d dissociation of H+5 cluster ions were discussed. Accord ing to theory, sta ble H+n cluster ions may be formed by H+3 core with one or more H 2 molecule. On the other hand, there exist conditions for the reactio n of H+3 and H2 in a rf ion source. In the experiments, the ion beam was accelera ted by van de Graff and selected by 90° analysis magnet in the condition of cur rent for mass number 5, and then diffracted by 20° analysis magnet, the energy spectrum of ion beam was obtained. From the spectrum, it is found that H+5 cluster ions may be formed from the ion-molecular interaction between H+3 ion and H2 neutral molecule in rf ion source and that there may exist H3 and H4 neutral clusters among the products of H+5 c luster ions.
Acoustic head wave on the borehole wall in a porous formation and the causes for its accompanying electromagnetic field
Authors: Hu Heng-Shan  ,   哈尔滨工业大学航天学院，哈尔滨  150001
Published: December 2020

To understand the propagation mechanism of the acoustic head wave and its accompanying electromagnetic field during logging in a porous formation, we studied the displacement characteristics of the wave. Calculations by both the fast compre ssional branch-cut-integral and the real-wavenumber-integral methods show that the head wave travels along the borehole wall with the fast compressional wave velocity, but it differs from a plane compressional wave in two aspects. First, the head wave causes radial displacement as well as axial displacement. Second, it is composed of the gradients of the fast and slow compressional potentials and the rotation of the shear potential. The gradient of the slow compressional potential constitutes the dominating part of the fluid filtration. It is the slow compressional potential that induces electric field that accompanies the acousti c head wave during acousto-electric well logging. And it is the shear potential that induces magnetic field that accompanies the acoustic head wave.
Field structure and electron density profile in circularly polarized femtosecond laser interaction with a linear plasma
Authors: He Feng  , Yu Wei  , Lu Pei-Xiang  ,   中国科学院上海光学精密机械研究所强光光学实验室，上海  201800
Published: December 2020

The electron density profile is solved self-consistently in circularly polarized femtosecond laser vertically interacting with a linear plasma. The result show s that a set of electron islands and cavities are produced in the relativistic p lasma. The laser energy is partially trapped in these cavities due to strong sta tic electric fields caused by the separation of electrons and ions. The dependen ce of the trapped static electric energy on the laser intensity is also discusse d.
Dynamic behaviours of an exciton confined in coupled quantum dots driven by a hi gh alternating current electrical field
Authors: Liu Cheng-Shi  , Ma Ben-Kun  ,   北京师范大学物理系,北京  100875
Published: December 2020

With the three-site Hubbard model and Floquet theorem, we investigate the dynamic behaviours of an exciton confined in three-quantum-dots molecules driven by an alternating current electrical field. The calculations show that the initia l localized state is hold up for a certain value of strength and frequency of th e alternating current field. In order to understand the dynamical property, we a pply the perturbation theory to solve the Floquet function and obtain the analyt ical solution of quasi-energy. We find that the dynamical localization can be bu ilt at the crossing point of quasi-energies for strong and moderate fields.
A novel single-electron analog-to-digital converter
Authors: Zhang Zhi-Yong  , Wang Tai-Hong  ,   中国科学院物理研究所,北京  100080
Published: December 2020

The ideal single-electron transistor has a folding I-V characteristic. Multi-threshold periodic transmitting function can be achieved by using a complementary single-electron transistor structure, which can be used to simplify the analog-to-digital(A/D) converter. A novel 3-bit A/D converter by using the complementary single-electron transistor structure has many advantages including a simple structure, high speed and low power.
A physical-based percolation model for gate oxide TDDB
Authors: Ma Zhong-Fa  , Zhuang Yi-Qi  , Du Lei  , Bao Jun-Lin  , Li Wei-Hua  ,   西安电子科技大学微电子研究所,西安  710071
Published: December 2020

Based on the physical mechanism of gate oxide TDDB, a percolation model for gate oxide degradation was brought forward, in which the occurrence and build up of deep energy-level defects, such as E′ center and oxygen vacancy were considered to be the right cause of oxide breakdown. It was pointed out that, during TDDB the stressed defects were produced in the oxide, which form local states in oxide forbidden gap. And the volume of these local states is directly proportional to the external electric field, especially when the field strength is high enough. With the by-pass of stressing time, the concentration of defects in the oxide grew continually. As an effect, the distance between neighboring local states become shorter. So, hopping or tunneling probabilities of electrons between these local states increase swiftly. As a result, a conduction path will form when the distance between neighboring local states reaches a critical value. At the same time, in terms of energy band theory, an extended energy level will form in the oxide forbidden gap. Accompanied by a rapid increase of SILC, the gate oxide undergoes breakdown.
Abnormal coercivity behaviour in the magnetic percolation region of a magnetic g ranular composite
Authors: Zhang Xiao-Yu  , Chen Ya-Jie  ,   苏州大学物理系,苏州  215006
Published: December 2020

MnZn-ferrite/SiO2 particle composites are prepared by mechanical ball ing. We study the relations of effective permeability μ, specific magnetization σ and coercivity Hc with the MnZn-ferrite concentration. The results indicate that an abrupt change emerges in effective permeability when the volume percentage of MnZn-ferrite particles is near V=98%, which means that a magnetic percolation phenomenon occurs in the system. Meanwhile, it is found that the coercivity Hc exhibits an anomalous behaviour that depends strongly on the microstructure of the composite. Above the percolation threshold, the variation of coercivity can be mostly explained in terms of dipolar interaction between magnetic particles, whereas below the percolation threshold, the decrement of Hc is ascribed dominantly to increasing specific magnetization σ. At the same time, we determine the measured percolation threshold Vc=97. 9%, which can be derived from the maximum of d2μ/dV2.
Colossal magnetoresistance effect in the perovskite-type La0.9Sb 0.1MnO3 material
Authors: Duan Ping  , Tan Guo-Tai  , Dai Shou-Yu  , Chen Zheng-Hao  , Zhou Yue-Liang  , Lü Hui-Bin  ,   中国科学院物理研究所，北京  100080
Published: December 2020

The colossal magnetoresistance oxide compound La0.9Sb0.1Mn O3 has been prepared by solid-state reaction method.The electrical transport and magnetic properties have been measured by superconducting quantum interference device magnetometer.The valence state of Sb is confirmed to be +5 through x-ray photoelectron spectroscopy,so this compound is an electron-doped colossal magnetoresistance material.
Hawking radiation of Dirac particles in a nonuniformly rectilinearly acceleratin g black hole with electric and magnetic charge
Authors: Zhang Jing-Yi  , Zhao Zheng  ,   (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;湛江师范学院物理系，湛江  524048
Published: December 2020

The Hawking radiation of Dirac particles on event horizon of nonuniformly rectilinearly accelerating black hole with electric and magnetic charge is studied in this paper. First, we construct the symmetrized null tetrad from which the spin coefficients and Dirac equation are derived. Next, by proposing a generalized tortoise coordinate transformation, the Dirac equation is decoupled successfully near the event horizon surface. Finally, following the method of Damour and Ruffini, the temperature on the horizon surface and the thermal spectrum formula of Dirac particles are obtained. The result is also discussed.
A type of expanding integrable system for NLS-mKdV hierarchy
Authors: Zhang Yu-Feng  , Yan Qing-You  ,   (1)山东财政学院经济统计系，济南  250014; (2)山东科技大学信息学院数学研究所，泰安  271019;中国科学院数学与系统科学研究院计算数学研究所，北京  100080
Published: December 2020

A subalgerbra 1, which is equivalent to the subalgebra of the loop al gebra 2 in “1997 Acta Math. Sin. 40 801”, is constructed by making use of algebraic t ransformation. Then a high-dimensional loop algebra is presented in terms of 1. An isospectral problem is established following by the use of direc t sum ope rators and isomorphic relations among subalgebras. It follows that a type of exp anding integrable system for the NLS_mKdV hierarchy of evolution equations is ob tained. As in reduction cases, the integrable couplings of the famous Schrding er equation and mKdV equation are presented.
The influence of density variation of a granular pile on the pressure distributi on at its bottom
Authors: Xie Xiao-Ming  , Jiang Yi-Min  , Wang Huan-You  , Cao Xiao-Ping  , Mario Liu  ,   (1)蒂宾根大学理论物理研究所,蒂宾根  72676  德国; (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;蒂宾根大学理论物理研究所,蒂宾根  72676  德国
Published: December 2020

We report that when the density at the centre of a cohesionless granular pile is slightly smaller than the density at its sides, such that the elastic strength at the centre is evidently smaller than the strength at the sides, the pressure distribution under the pile will show a dip at the centre. For the conical (or w edge-shaped) piles formed by slowly pouring grains from a point (or a line), the small density variation may be due to the phenomenon that the pile is slightly tapped by the down-rolling grains along the pile surfaces. The computation shows that the observed pressure distribution can be well reproduced by the elastic t heory with a spatial-varying bulk modulus.
In-situ study on structural relaxation of Zr55Cu30Al1 0Ni5bulk amorphous alloy by SAXS
Authors: Liu Yi  , Liu Lin  , Wang Jun  , Zhao Hui  , Rong Li-Xia  , Dong Bao-Zhong  ,   (1)华中科技大学材料学院,武汉  430074; (2)中国科学院高能物理研究所同步辐射实验室,北京  100039; (3)中国原子能科学研究院,北京  102413
Published: December 2020

The structural relaxation of Zr55Cu30Al10Ni5 bulk amorphous alloy during annealing at 360 and 380℃ have been investigated by in-situ synchrotron radiation x-ray small angle scattering (SAXS). The experimental results o btained show that the fluctuations of electron density during the annealing proc ess are due to structural relaxations of bulk amorphous alloy before cyrstalliza tion. It is found that a homogenization in electron density takes place during a nnealing, which is attributed to the change from topological short-range order (TSRO) structural relaxation to chemical short-range order (CSRO) structural relaxation. The annealing time required for this change becomes shorter as the annealing temperature increases.
Linear optical absorption properties and internal electromagnetic field distribu tions of periodic multiple quantum wells
Authors: Xiao Wan-Neng  , Zhao Ji  , Wang Wei-Jiang  , Li Run-Hua  , Zhou Jian-Ying  ,   中山大学光电材料与技术国家重点实验室，广州  510275
Published: December 2020

Linear absorptive properties of the periodic multi-quantum well (MQW) structures are studied. It is found that the absorption is determined by the interplay of pulse widths, layer number N and periods. A threshold existing in N divides Bragg absorption into a rising and dropping regions. The corresponding maximum is an independent constant. Absorptions for non-Bragg arrangement keeps monoton ously increasing with its first part almost coinciding with the corresponding Br agg absorptions.This demonstrates a dramatic Bragg suppression,which never appea rs in the rising region. Further more, the Beer's law is proved to be still exac tly suitable for periodic structures.
Study on principal refractive indices of the ferroelectric single crystal 0.62Pb (Mg1/3Nb2/3)O3-0.38PbTiO3
Authors: Wan Xin-Ming  , He Tian-Hou  , Lin Di  , Xu Hai-Qing  , Luo Hao-Su  ,   中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海  201800
Published: December 2020

The refractive indices and their dispersions in 0.62Pb(Mg1/3Nb2/ 3)O 3-0.38PbTiO3(PMNT62/38)single crystals were accurately mea sured with the min imum deviation method at 20℃.The parameters of modified Sellmeier's equation fo r both no and ne are obtained.We relate the refractive ind ices to energy-ban d structure of oxygen-octahedron ferroelectrics and the Sellmeier optical coeffi cients,E0=5.50eV,λ0=0.226μm，Ｓ０=1.004×1014m-2 and Ed=28 .10eV for n0 and Ｅ0=5.57eV,λ0=0.223μm，S0=1.017×1014m-2 and Ed=28.10eV for ne were obtained through fitting the si ngle-term oscillat or equation.For materials with ABO3 perovskite structure,the octahedr al BO6 unit governs the lower lying conduction bands and the upper valence bands and ma kes a substantial contribution to the refractive indices.
Diagnosis of VHF plasmas with optical emission spectroscopy
Authors: Yang Hui-Dong  , Wu Chun-Ya  , Li Hong-Bo  , Mai Yao-Hua  , Zhu Feng  , Zhou Zhen-Hua  , Zhao Ying  , Geng Xin-Hua  , Xiong Shao-Zheng  ,   (1)南开大学光电子所，天津  300071; (2)南开大学光电子所，天津  300071;东华大学理学院，上海  200051
Published: December 2020

Very high frequency (VHF) Plasma and its glow discharge mechanism during the deposition of μc-Si:H film have been studied by means of optical emission spectroscopy (OES) technique in this paper.From the measured OES spectra,where the valuable information on the Si,SiH,H and H2 intensities were provided,the influence of deposition conditions on the VHF plasma has been investigated.The intensitie s of SiH,H2 and H of VHF-gas deposition(GD) to deposit μc-Si:H were much high er than those of RF-GD to deposit a-Si:H.Under the experiment condition to depos it μc-Si:H,Si,SiH,the H and H2 intensities increased obviously with the excit ation frequency,and the variation of the deposition rate with the excitation fre quency was similar to that of SiH.The SiH intensity of VHF-GD became higher than its Si intensity as the hydrogen dilution ratio decreased.The influences of the hydrogen dilution ratio on the plasma optical emission spectra also depended on the reaction pressure,the excitation power as well as the excitation frequency. In the case of the hydrogen ratio (R=H2/SiH4)R=23,the SiH intensity decrease d monotonously against the excitation pressure at a low excitation power (e.g.5W ).But the SiH intensity increased at first, then decreased with the increase of the pressure at the high excitation power (e.g.11-55W).In the case of the hydrog en ratio R=5.7,the SiH intensity decreased monotonously against the excitation p ressure for all the excitation power.The Si,SiH,H and H2 intensities also incr eased with the excitation power and then trended to be saturated,and they are ea sier to saturate with the increase of the hydrogen dilution ratio.All the experi mental results demonstrated that the influences of the excitation frequency,the excitation power,the reaction pressure and the hydrogen dilution ratio were correlative,none of the deposition conditions is the critical factor to improve the deposition rate.
Theoretical simulations of preparation of nanometal Particles by Flow-levitation Method
Authors: Tang Yong-Jian  , Wei Jian-Ｊun  , Li Chao-Ｙang  , Wu Wei-Ｄong  , Wang Chao-Ｙang  ,   (1)中国工程物理研究院激光聚变研究中心，绵阳919信箱981分箱  621900; (2)中国工程物理研究院激光聚变研究中心，绵阳919信箱981分箱  621900;四川大学原子与分子物理研究所，成都  610065
Published: December 2020

This paper describes the principle of flow-levitation method. An analytical mode l for preparation of nanometal powders in inert gases is presented. Associated w ith the relation between dynamics of gas flow and temperature, the process of th ermal diffusion, nucleation, condensation and crystallization of powders is stud ied. The results of theoretical analysis are in agreement with the practice.It i ndicates that we can control the particle-size distribution by choosing appropri ate characteristic technological parameters.
The computation of free energy of TIP4P water using expanded ensemble method
Authors: Sheng Zheng-Mao  , Luo Jun-Wei  ,   浙江大学物理系，杭州  310028
Published: December 2020

The free energy of the TIP4P water is computed by expanded ensemble method,which allows us to calculate absolute free energies with a high precision for arbitrary systems using a relative simple computational scheme.The free energy of NVT ensemble of TIP4P water is -21.485±0.035kJ/mol,which is in accordance with the r esults obtained by using other method.A method for choosing crucial parameters ( balance factors)is proposed.
Stability for the equilibrium state of rotational relativistic Birkhoffian systems
Authors: Fu Jing-Li  , Chen Li-Qun  , Xue Yun  ,   (1)上海大学上海市应用数学和力学研究所，上海  200072; (2)上海大学上海市应用数学和力学研究所，上海  200072;商丘师范学院数学力学和数学物理研究所，商丘  476000
Published: December 2020

The stability for equilibrium state of rotational relativistic Birkhoffian systems is studied.The equilibrium state equations, the disturbance equation and the first approximation equation are given.The stability criteria for equilibrium state,and the stability criteria of the direct method for the rotational relativistic Birkhoffian autonomous systems are obtained.The relationship of the stability of equilibrium state between rotational relativistic Birkhoffian systems and rotational classical Birkhoffian systems are discussed. Two examples are presented to illustrate the results.
A Darboux transformation and new exact solutions for Broer-Kaup system
Authors: Zhou Zhen-Jiang  , Li Zhi-Bin  ,   (1)华东师范大学计算机科学技术系，上海  200062); (2)华东师范大学计算机科学技术系，上海  200062;牡丹江大学机电系，牡丹江  157011
Published: December 2020

An explicit Darboux transformation for Broer-Kaup (BK) system is constructed with the aid of the elemental solutions of its Lax pairs.From the Darboux transformation,the new two-soliton solutions for BK system are obtained.
Trapping effect modeling for SiC power MESFETs
Authors: Yang Lin-An  , Zhang Yi-Men  , Yu Chun-Li  , Zhang Yu-Ming  ,   西安电子科技大学微电子研究所，西安  710071
Published: December 2020

An analytical trapping modle, which utilizes concise parameters to describe the impact of deep level traps in the p-buffer layer on the output characteristics, is proposed for 4H-SiC RF power MESFET. This model is simple in calculations compared with normally used 2D numerical model. It also takes into account the self-heating effect that plays an important role in saturated region of I-V characteristics. The description of transconductance degradation, drain conductance decrease and pinch-off voltage dispersion caused by the traps is easily derived by theoretical analysis. The result shows good agreement between simulations and measurements.
Calculation of electron capture probabilities in collisions of O５＋ ion with H atom
Authors: Wang Li-Guang  , Wang Jun  ,   (1)江南大学理学院,无锡  214036; (2)江南大学理学院,无锡  214036;黑龙江大学物理系,哈尔滨  150080
Published: December 2020

A method, in which the wave function is expanded with the atomic orbitals added to the electron transfer factor to correct the boundary condition, is used to study the collisions between O５＋ ion and H atom. After calculating the initial channel potential energy of O５＋+H system, the good agreement between calculation and experiment shows that optimized calculation factors are highy reliable. The electron capture probabilities vs time in the interaction of O５＋ ion with H atom (8Σ states) are calculated at an impact factor b=8.0 a.u. and an impact speed v=220.0 a.u. by using the core approximation and the optimized factors.
Measurement of superposition of orbit angular momentum states of photons by fork-like grating
Authors: Ye Fang-Wei  , Li Yong-Ping  ,   (1)中国科学技术大学物理系,合肥  230026; (2)中国科学技术大学物理系,合肥  230026;中国科学技术大学结构分析开放实验室,合肥  230026
Published: December 2020

Laguerre-Gaussian(LG) mode carries a well-defined orbit angular momentum. We have designed a fork-like grating to measure the superposition of two LG modes. It is useful in the high-dimensional quantum communication.
Electron temperature measurement of low-energy laser produced plasma using iso-electronic x-ray spectroscopy
Authors: Yang Jia-Min  , Ding Yao-Nan  , Chen Bo  , Zheng Zhi-Jian  , Yang Guo-Hong  , Zhang Bao-Han  , Wang Yao-Mei  , Zhang Wen-Hai  ,   中国工程物理研究院激光聚变研究中心,绵阳市919-986信箱，绵阳  621900
Published: December 2020

Low-Z CHO targets were illuminated by a low-energy laser beam on Xingguang laser facility to produce relatively low-temperature plasma. The ratios of spectrum intensity of the carbon ions to the oxygen ions have been measured by a 2400 lines per millimeter grating spectrometer in order to obtain the electron temperature. The diagnostics on low electron temperature has been developed.
Effects of substrates on silicon oxide nanowires growth by thermal chemical vapor deposition
Authors: Yan Xiao-Qin  , Liu Zu-Qin  , Tang Dong-Sheng  , Ci Li-Jie  , Liu Dong-Fang  , Zhou Zhen-Ping  , Liang Ying-Xin  , Yuan Hua-Jun  , Zhou Wei-Ya  , Wang Gang  ,   中国科学院物理研究所,中国科学院凝聚态物理中心,北京  100080
Published: December 2020

Silicon oxide nanowires, grown on (100) Si wafers with the oxide layer about 100nm in thickness and on quartz plates, are investigated by exposing to the same conditions in a thermal chemical vapor deposition reactor at a temperature about 860℃. Field-emission scanning electron microscopy, transmission electron microscope equipped with energy-dispersive x-ray analysis were used to characterize the samples. The results show that a large amount of amorphous silicon oxide nanowires was obtained. The morphology, size and chemical composition of the silicon oxide nanowires grown on different substrates are quite different. The reasons of forming different characteristic silicon oxide nanowires were discussed.
Behaviors of multi-node superconducting rings in external magnetic field
Authors: Liu Xin-Yuan  , Xie Fei-Xiang  , Wang Fu-Ren  , Ma Ping  , Dai Yuan-Dong  ,   (1)北京大学物理系，人工微结构和介观物理国家重点实验室，北京  100871; (2)北京大学物理系，人工微结构和介观物理国家重点实验室，北京  100871;北京大学电子学系，北京  100871
Published: December 2020

Numerical simulations and analyses have been applied to find the relationships between magnetic flux,ring current,free energy of superconducting rings and external magnetic field.It is found that a double-junction superconducting ring has a different behavior from a single-junction ring.When the Ic values are identical,a double-junction ring has a non-hysteresis behavior when β＜2.The hysteresis exists only when β≥2.And a double-junction ring has a double-branch solution with 2Φ0 period.
Single-electron control by single-electron pump and its stability diagrams
Authors: Wu Fan  , Wang Tai-Hong  ,   中国科学院物理研究所，北京  100080
Published: December 2020

Based on both Coulomb blockade and single-electron tunneling, the single-electron control by a single-electron pump is discussed.The stability diagram is obtained by considering its equivalent circuit in terms of the electrostatic energy.One of Its applications is discussed by analyzing its stability diagram.Our results show that random charges on the gate have less influence on the control of small curerent.
Simulation of magnetization behaviour in nanocrystalline Pr2Fe14B by micromagnetic finite element method
Authors: Zhang Hong-Wei  , Rong Chuan-Bing  , Zhang Jian  , Zhang Shao-Ying  , Shen Bao-Gen  ,   中国科学院物理研究所与凝聚态物理中心磁学国家重点实验室，北京  100080
Published: December 2020

Magnetization behaviour in the nanocrystalline Pr2Fe14B has been simulated by micromagnetic finite element method. The decrease of anisotropy in an interlayer leads to the drop of coercivity and enhancement of remanence, while the decline of intergrain exchange coupling increases the coercivity and decreases the remanence. The experimental coercivity and remanence may be simultaneously obtained by selecting proper parameters for the interlayer. Unfortunately, it is difficult to simulate the demagnetization curve of the ribbons before many efforts mustbe paid in future.
Control of period-doubling bifurcation and chaos in a discrete nonlinear system by the feedback of states and parameter adjustment
Authors: Luo Xiao-Shu  , Chen Guan-Rong  , Wang Bing-Hong  , Fang Jin-Qing  , Zou Yan-Li  , Quan Hong-Jun  ,   (1)广西师范大学物理与电子科学系，桂林  541004; (2)华南理工大学应用物理系，广州  510641; (3)香港城市大学电子工程系，香港 九龙; (4)香港城市大学电子工程系，香港 九龙;中国科学技术大学近代物理系，合肥  230026;广西师范大学物理与电子科学系，桂林  541004; (5)中国科学技术大学近代物理系，合肥  230026; (6)中国原子能科学研究院，北京  102413
Published: December 2020

In this paper, the control of delaying period-doubling bifurcations and unstable periodic orbits embedded in a chaotic attractor of a discrete nonlinear dynamical system is effectively realized by using the state variables feedback and parameter variation. Moreover, the 2n periodic orbits of the system can be controlled into the　2m (m<n) periodic orbits by the methods proposed.
Stochastic resonance in two-dimensional Brownian motion in the weak noise limit
Authors: Kang Yan-Mei  , Xu Jian-Xue  , Xie Yong  ,   西安交通大学建筑工程与力学学院非线性动力学研究所，西安  710049
Published: December 2020

The theory of LΩEGF and the scaling theory on multidimensional Fokker-Planck equations with gradient potential are applied to derive the probability transition rate for Brownian motion in a symmetric two-dimensional bistable potential. Based on the rate method in adiabatic elimination, the phenomenon of stochastic resonance is studied in this system. Compared with the known results, the analytic expression for signal-to-noise ratio derived in this study is independent of the intensity of friction,i.e. not only applicable to an overdamped system, but also applicable to a lightly damped system. Numerical simulations fruther verify the significance of the analytically approximate result.
Study of the spectral characters of stimulated Raman scattering in highly elliptical-core optical fibres
Authors: Zhang Xi-He  , Yao Zhi-Hai  , Li Xiao-Ying  , Li Chun-Ming  , Feng Ke-Cheng  , Wang Zhao-Min  ,   长春理工大学光学物理系,长春130022
Published: December 2020

In this paper, we systematically study the spectral characters of stimulated Raman scattering(SRS) in the birefringence optical-fibre and give seventh-order Stokes and first-order anti-Stokes spectra, then measure the threshold、spectrum width and Raman gain of SRS. At the same time, we make an analysis of the mechanism of energy transmission between each order of the Raman spectra.
The theory and realization of atomic beam CGH
Authors: Shi Jian-Ping  , Chen Xu-Nan  , Gao Hong-Tao  , Chen Xian-Zhong  ,   中国科学院光电技术研究所微细加工光学技术国家重点实验室,成都610209
Published: December 2020

The realization of atom-beam holography by computer generated hologram have been presented in this paper, which can decrease the difficulty of the atom holography. Firstly the wave nature and cooling mechanism of atoms are analyzed, then the design process and a facture of the atomic SiN film hologram is shown, and finally we present a theoretical plan and the picture of an experiment system.
Compare of characteristics between Martinez and Offner stretchers used in chirped pulse amplifier
Authors: Sun Da-Rui  , Song Yan-Rong  , Zhang Zhi-Gang  , Liu Yong-Jun  , Chai Lu  , Wang Qing-Yue  ,   (1)天津大学精密仪器与光电子工程学院超快激光研究室，光电信息技术科学教育部重点实验室，天津  300072; (2)天津大学精密仪器与光电子工程学院超快激光研究室，光电信息技术科学教育部重点实验室，天津  300072;天津大学理学院应用物理系，天津  300072
Published: December 2020

In this paper, the characteristics and range of application of the Martinez and the Offner stretchers in a chirped pulse amplifier system is analyzed theoretically for a multiple-pass amplifier and a regenerative amplifier respectively. The Martinez stretcher can completely compensate the dispersion introduced either from a multiple-pass amplifier or from a regenerative amplifier within a certain bandwidth. In a regenerative amplifier, if it is necessary to obtain broader pulses, the compact Offner stretcher can be applied.
Numerical analysis of alloy molten pool heated by electron gun
Authors: Bo Yong  , Wang De-Wu  , Ying Chun-Tong  ,   清华大学工程物理系，北京  100084
Published: December 2020

The physical model for a square alloy molten pool heated by an electron gun is described by the Navier-Stokes, energy and species concentration equations. The velocity, temperature and concentration distributions of the two-dimensional pool are analyzed by the finite difference method. The relations between the metal solvent evaporation rate and Rayleigh number Re, Prandtl number Pr, Grashof number Gr and Lewis number are studied in detail. In general, the solvent evaporation rate increases with decreasing Rayleigh number,decreasing Prandtl number, increasing Grashof number and increasing Lewis number, so the power use ratio of the electron gun increases. On this basis, such metal solutes as wolfram, neodymium and chromium is intermingled to such involatile metal solvents as thorium, platinum, ytterbium and ruthenium, and the numerical results indicate that the metal solvent evaporation rate increases.
D-T plasma of self-sustained burning under high performance
Authors: Gong Xue-Yu  , Shi Bing-Ren  , Long Yong-Xing  ,   (1)核工业西南物理研究院，成都  610041; (2)南华大学核科学技术学院，衡阳  421001
Published: December 2020

By adopting a Bohm-type thermal diffusion coefficient related to the energy confinement enhancement factor H within the conventional magnetic shear regime,and a mixed Bohm-gyro-Bohm thermal diffusion coefficient related to the shear within the negative central magnetic shear regime,considering the effect of the α particle anomalous diffusion and the dynamic feedback heating,and starting from energy transport of electrons and ions,we have studied the high performance self-sustaining burning deuterium-tritium plasma under a given plasma density profile for the two different kinds of magnetic shear regimes.Some conclusions are obtained:under the conventional shear,only when H≥3,the D-T burning can produce a large power output,and when H is larger than a certain value(H≈4),D-T plasma self-sustained burning can be maintained without the dynamic feedback heating;under the negative central shear,the plasmas have a higher plasma performance and a larger power output than that under conventional shear,and D-T plasma self-sustained burning can be maintained without the dynamic feedback heating power,the suitable alpha particle diffusion is advantage ous to D-T plasma burning under the conventional shear,and D-T self-sustained burning cannot be maintained under a large α particle anomalous diffusion for the negative central shear.The dynamic feedback heating power is important for sustaining D-T plasma burning under the conventional shear.
Structural and photoluminesenct properties of Zn1-xMgxO thin film on silicon
Authors: Zou Lu  , Wang Lei  , Huang Jing-Yun  , Zhao Bing-Hui  , Ye Zhi-Zhen  ,   浙江大学硅材料国家重点实验室，杭州  310027
Published: December 2020

High-quality Zn1-xMgxO thin film was grown on Si substrate by pulsed laser deposition (PLD). x-ray diffraction patterns indicated that the film was c-axis oriented, the full width at half maximum of (002) peak was only 0.211°, and no phase separation was observed. Transmission electron microscopy(TEM) verified the c-axis orientation of the Zn1-xMgxO thin film. Regular diffraction spots can be observed by TEM. Photoluminescence spectrum was measured at room temperature. The near-band-energy emission peak of the Zn1-xMgxO thin film has a blue shift of 0.4 eV from that of ZnO, and the ratio of near-band-energy to the defect-level peak intensity was as large as 159. These results indicate that Zn1-xMgxO thin film can have potential applications in optoelectronic devices.
Study on the kink effect in AlGaAs/InGaAs/GaAs PHEMTs
Authors: Liu Hong-Xia  , Hao Yue  , Zhang Tao  , Zheng Xue-Feng  , Ma Xiao-Hua  ,   西安电子科技大学微电子研究所，西安  710071
Published: December 2020

In this paper, two-dimensional devices simulation program-MEDICI has been used to simulate AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistors (PHEMTs). Doping and electron concentrations, current flow and gate characteristic in PHEMTs are studied. The kink effect in PHEMTs is investigated emphatically as a function of temperature and doping concentration of Schottky layer. The results show that the kink effect is related mainly to the trapping/detrapping process of deep levels that lie in the top layers but not related to the impact ionization alone.
Generalized Collin principle of an isolated conductor and multi-conductor systems
Authors: Liang Chang-Hong  , Su Tao  , Wan Ji-Xiang  ,   西安电子科技大学电子工程学院，西安 710071
Published: December 2020

The Collin principle has been used to estimate the upper bound and lower bound of practical capacitance,which gave out many simple and applicable results.The principle is generalized to the three-dimensional isolated and multi-conductor systems in this paper.Some applicable examples are given by using the approximate method of equal surface area.
Research on B0→K0π0 decay
Authors: Wu Xiang-Yao  , Yin Xin-Guo  , Guo Yi-Qing  , Zhang Xiao-Bo  , Yin Jian-Hua  , Xie Yuan-Liang  ,   (1)淮北煤炭师范学院物理系，淮北 235000; (2)淮北煤炭师范学院物理系，淮北 235000;南开大学物理学院，天津 300071; (3)吉林大学物理系,长春 130025; (4)南开大学物理学院，天津 300071;中国科学院高能物理研究所，北京 100039; (5)中国科学院长春光学精密机械与物理研究所,长春 130022
Published: December 2020

In this paper, the hadronic matrix element of B0→K0π0 decay is calculated systematically, which includes the contribution of factorization in the leading order, the O(αs) correction from hard gluon exchange and the correction from soft gluon exchange. The soft gluon exchange cannot be calculated in quantum chromodynamics(QCD) factorization as well as in perturbed QCD, but it can be calculated in terms of the light cone QCD sum rules,and the calculation shows that the amplitudes of soft gluon exchange, the factorization in the leading order and the O(αs) correction in the decay channel are of the same order of magnitude. So, the soft gluon exchange effect cannot be neglected. Finally, the branch ratio is calculated and it is consistent with the experimental result.