bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of luminescence due to delocalized exciton recombination in asymmetric-coupled quantum well structure based on Ξ-type configuration
Authors: Hu Zhen-Hua  , Huang De-Xiu  ,   (1)华中科技大学光电子工程系，武汉 430074; (2)华中科技大学光电子工程系，武汉 430074;武汉理工大学物理系，武汉 430063
Published: December 2020

The luminescence properties due to the delocalized exciton recombination in the asymmetric-coupled quantum well (ACQW) structure have been studied based on Ξ-type configuration.We show that the luminescence has mainly two emission peaks:one peak corresponds to the red shift relative to the central transition frequency and the other to the blue shift.Compared with the single quantum well,this quantum-confined Stark shift is very sensitive to electric field.This means that the coupling between two wells for an ACQW structure leads to the enhancement of the quantum-confined Stark effect.From this optical property of ACQW,novel ultrafast optical modulation devices and optical switch fabricated with ACQW structure can be expected in the future optical communication system.
A study of linear and the second nonlinear admittance about the charge polarization around junction-boundaries in a quantum cavity structure
Authors: Zhao Xue-An  , He Jun-Hui  ,   (1)浙江大学近代物理中心,杭州 310027; (2)浙江大学物理系,杭州 310027
Published: December 2020

We present explicit expressions for the linear and the second nonlinear imaginary parts of admittanc (emittance) for the charge polarization of accumulation on both sides of the quantum dot (cavity) junctions by using Green function and the coupling parameters in an effective Hamiltonian and the discrete potential model. We found that the emittance and the electrochemical capacitance are equal to the geometric capacitance in the classical limit. In the nonclassical case the emittance is equal to the electrochemical capacitance, but not equal to the geometric capacitance if there is complete reflection. In the case where there is tunneling the emittance and electrochemical capacitance as well as the geometric capacitance are different. The results may be helpful for measurements on capacitance on small-scale structures.
Influences of a magnetic field on the persistent currents of mesoscopic coupling metallic ring
Authors: Ji Ying-Hua  , Liu Yong-Mei  , Xin Jian-Zhi  , Xie Fang-Sen  , Lei Min-Sheng  ,   (1)江西师范大学数学与信息科学学院，南昌 330027; (2)江西师范大学物理与通信电子学院，南昌 330027; (3)江西师范大学物理与通信电子学院，南昌 330027;江西省光电子与通信重点实验室，南昌 330027
Published: December 2020

Based on the discreteness of electric charge, the influences of an external magnetic filed on the persistent current of the mesoscopic coupling metallic rings are investigated. The results obtained indicate that there is an additional persistent current in each mesoscopic metallic ring. The additional persistent currents are related to the circuit parameter and coupling coefficient. If the external magnetic flux varies according to sine law, the effect of double-frequency and division-frequency appears in these rings.
Characteristics of structure and carrier localization in YBCO systems doped with magnetic ions Fe and Ni
Authors: Li Ping-Lin  , Zhang Jin-Cang  , Chao Gui-Xin  , Deng Dong-Mei  , Liu Li-Hua  , Dong Cheng  , Jing Chao  , Cao Shi-Xun  ,   (1)上海大学物理系,上海 200436; (2)中国科学院物理研究所,北京 100080
Published: December 2020

To make clear the physical mechanism of substitution by the magnetic ions Fe and Ni in different sites in YBCO systems, the positron annihilation technology (PAT) and simulated calculations are utilized to systemically investigate the compounds YBa2Cu3-x（Fe，Ni）xO7-δ（x=0.0—0.5）. The results obtained show that the doping ions Fe and Ni form different kinds of ion clusters and enter the crystal lattice. When occupying Cu(2) sites in CuO2 planes, the ions gather into double square and/or other clusters, which results in a strong electronic localization and would directly affect the pairing and transportation of carriers, so the superconductivity is suppressed dramatically. While ions substitution for Cu(1) through gathering hexamer and/or other clusters, this induces the localization of holes and weakens the function of carrier reservoir; thus carriers cannot easily transfer to CuO2 planes. However, in this case, the pairing and transportation of carriers are not affected directly, thus the superconductivity will be suppressed weakly. On the other hand, the present results indicate the suppression of superconductivity has no direct correlation with the magnetism of Fe and Ni ions itself.
Exchange coupling in FeMn/NiFe bilayers
Authors: Jiang Hong-Wei  , Li Ming-Hua  , Wang Ai-Ling  , Zheng Wu  ,   (1)北京科技大学材料物理系,北京 100083; (2)首都师范大学物理系,北京 100037
Published: December 2020

Planar Hall effects in exchange biased FeMn/NiFe bilayers were measured under magnetic fields rotated in the film plane. Detailed magnetic anisotropy analysis shows that there is no additional uniaxial anisotropy induced by the interfacial coupling in this system, while the instability of anti-ferromagnetic grains or the formation of many domains in ferromagnetic layer may play an important role responsible for the difference between exchange biasing fields obtained by reversible and irreversible measurements.
Effect of inner electric field on the photoluminescence spectrum of nanosilicon
Authors: Huang Kai  , Wang Si-Hui  , Shi Yi  , Qin Guo-Yi  , Zhang Rong  , Zheng You-Dou  ,   南京大学物理系,固体微结构国家重点实验室, 南京 210093
Published: December 2020

Based on the quantum confinement-luminescence center model, the relation between the inner electric field (IEF) and the photoluminescence(PL) character is calculated. Results show that the IEF between nanosilicon and luminescence centers (LCs) can have a strong effect on the carrier recombination rate and the spectrum peak position swinging. In the range from 2 to 5 nm, the carrier recombination rate at the LCs is much bigger than the rates of recombination inside the nanosilicon. And dut to the presence of IEF between nanosilicon and LCs, the PL intensity at the LCs and inside nanosilicon will reduce remarkably.
Thickness measurement of GaN film based on transmission spectra
Authors: Zhang Jin-Cheng  , Hao Yue  , Li Pei-Xian  , Fan Long  , Feng Qian  ,   西安电子科技大学微电子研究所,西安 710071
Published: December 2020

By analyzing the transmission spectra of hetero-epitaxial GaN films on sapphires, a film thickness measurement method is presented. The method uses the interference effect of the crystal film and considers the effect of the refractive index n on the photon wavelength. Applications of it show that the method is a rapid and precise one for measuring the film thickness of GaN crystals.
Determination of the transition-layer thickness of a crystalline polymer by using small-angle x-ray scattering
Authors: Zhao Hui  , Guo Mei-Fang  , Dong Bao-Zhong  ,   (1)中国科学院高能物理研究所同步辐射实验室,北京 100039; (2)中国科学院高能物理研究所同步辐射实验室,北京 100039;鞍山师范学院物理系,鞍山 114005; (3)中国石油化工股份有限公司北京化工研究院,北京 100013
Published: December 2020

The thickness of transition layer of a crystalline polymer is generally calculated by one-dimensional electron density correlation function. If the transition layer of the crystalline polymer is diffusive, the corrected Porod's law is an effective method to deal with the diffuse transition layer of pseudo two-phase material. The method of Porod's law is used to compute the thickness of transition layer of crystalline polymer and compared with that of correlation function. The conclusion is that the two methods obtain identical thickness of the transition layer.
Study on the growth of aligned carbon nanotubes controlled by ion bombardment
Authors: Wang Bi-Ben  , Zhang Bing  , Zheng Kun  , Hao Wei  , Wang Wan-Lu  , Liao Ke-Jun  ,   (1)北京工业大学应用数理学院,北京 100022; (2)重庆大学数理学院,重庆 400044
Published: December 2020

Aligned carbon nanotubes were prepared by plasma-enhanced hot filament chemical vapor deposition using CH4, H2, and NH3 as reaction gases. It was investigated how different negative bias affects the growth of aligned carbon nanotubes. The results indicate that the average diameter of the aligned carbon nanotubes is reduced and the average length of the aligned carbon nanotubes is increased with increasing negative bias. Because of the occurrence of glow discharge, a cathode sheath forms near the substrate surface, and a number of ions are produced in it, and a very strong electrical field builds up near the substrate surface. Under the effect of the field, the strong bombardment of ions on the substrate surface will influence the growth of aligned carbon nanotubes. Combined with related theories, we have analyzed and discussed the ion bombardment effects on the growth of the aligned carbon nanotubes.
Nano-graphite synthesized by explosive detonation and its application in preparing diamond under high-pressure and high-temperature
Authors: Wen Chao  , Sun De-Yu  , Li Xun  , Guan Jin-Qing  , Liu Xiao-Xin  , Lin Ying-Rui  , Tang Shi-Ying  , Zhou Gang  , Lin Jun-De  , Jin Zhi-Hao  ,   (1)西安交通大学金属材料强度国家重点实验室,西安 710049; (2)西安交通大学金属材料强度国家重点实验室,西安 710049;西北核技术研究所,西安 710024; (3)西北核技术研究所,西安 710024
Published: December 2020

In this article, preparation of nano-graphite powders in a steel chamber by using pure TNT (trinitrotoluene) explosives has been reported. X-ray diffraction results indicated that the black solid powders which were collected from the wall and the bottom of the chamber after detonation have the graphite structure and the average size of the particles of the graphite is 1.86-2.58 nm. Transmission electron microscopy confirms that the black powder is hexagonal-graphite structure with ball or ball-like shape. The grain size of the nano-graphite measured by small angle x-ray scattering lies in the range of 1-50 nm, 92.6wt% of the powder particles is smaller than 16 nm and the average diameter of the grains is 8.7 nm. Specific surface area of the nano-graphite is about 500-650 m2/g. Using nano-graphite as carbon source and choosing Fe powders as the catalyst, the ball-like and lumpy diamonds of 5-15 μm have been synthesized under high-temperature and high-pressure conditions of 1250-1330 K and 5.1 GPa. The synthesized temperature is about 300 K lower than that of bulk graphite synthetic diamond.
Studies on the preparation and characterization of Bi4Ti3O12 thin films on p-Si substrates
Authors: Wang Hua  ,   桂林电子工业学院通信与信息工程系, 桂林 541004
Published: December 2020

High-quality Bi4Ti3O12 ferroelectric thin films on p-Si substrates were prepared by using the sol-gel technique. The growth behavior, ferroelectric properties, C-V characteristic and fatigue characteristic of Bi4Ti3O12 were investigated. The results show that the growth of Bi4Ti3O12 on bare p-Si substrates is c-axis-oriented with the increase of annealing temperature, and the apparent dependence of the ferroelectric properties of Bi4Ti3O12 films on the grain size, growth behavior and carrier concentration stems from the temperature effects. The C-V hysteresis curves with clockwise loops proved that the Ag/Bi4Ti3O12/p-Si heterostructure can realize a memory effect due to the ferroelectric polarization of Bi4Ti3O12 films and the remnant polarization of the Bi4Ti3O12 films reduced by 12% of the initial value after 109 bipolar switching cycles, which indicated that these Bi4Ti3O12 films deposited on p-Si substrates would be qualified for ferroelectric memories.
Noether symmetry and Hojman conserved quantity for nonholonomic mechanical systems
Authors: Luo Shao-Kai  , Guo Yong-Xin  , Mei Feng-Xiang  ,   (1)北京理工大学理学院,北京 100081; (2)辽宁大学物理系,沈阳 110036; (3)浙江工程学院数学力学与数学物理研究所，杭州 310018
Published: December 2020

A nonNoether conserved quantity, i. e. Hojman conserved quantity constructed using the Noether symmetry for the nonholonomic mechanical system is presented. Under special infinitesimal transformations in which the time is not variable, the special Noether symmetry and Noether conserved quantity are given, and the condition under which the special Noether symmetry is a special Lie symmetry is obtained. From the special Noether symmetry, the Hojman conserved quantity of the corresponding holonomic system, the weakly Hojman conserved quantity and the strongly Hojman conserved quantity of the nonholonomic systems are obtained. An example is given to illustrate the application of the result.
An extension of Lie algebra and a related integrable system
Authors: Zhang Yu-Feng  , Guo Fu-Kui  ,   山东科技大学信息学院数学研究所,泰安 271019
Published: December 2020

A direct extension of the known Lie algebra An-1 is presented, a new Lie algebra gl(n,C) is obtained. For the sake of application convenience, Lie algebra gl(3,C) is only considered, whose subalgebra is constructed. By the definition of the subalgebra gradation,a new loop algebra is shown. As its application, an isospectral problem is designed. It follows that a new Lax pair is obtained. By making use of Tu scheme, a family of new Liouville integrable system is resented, which possesses a biHamiltonian structure. As the reduction case of the hierarchy obtained, a new coupled generalized Schrdinger equation is obtained.
Four kinds of raising and lowering operators of three-dimensional isotropic harmonic oscillators with spin-orbit coupling
Authors: Fu Mei-Huan  , Ren Zhong-Zhou  ,   (1)南京大学物理系,南京 210008; (2)南京大学物理系,南京 210008；南京工业职业技术学院,南京 210007
Published: December 2020

The method of raising and lowering operator is used to solve the problem of threedimensional isotropic harmonic oscillator with Spinorbit coupling. The energy level splitting of the harmonic oscillator is analyzed and discussed.
Numerical research on critical temperature of Bose-Einstein condensation for gas with interaction in harmonic trap
Authors: Wang Chong  , Yan Ke-Zhu  ,   曲阜师范大学物理系,曲阜 273165
Published: December 2020

In this article we study BoseEinstein condensation of the gas with interactions in a harmonic trap using a numerical method. The distribution of the energy states was given, by which the author calculated the shift of the critical temperature and made a comparison with the situation without interactions. We have obtained a positive shift of critical temperature for systems with repulsive interaction, and a negative one for systems with attractive interaction.
Time evolution of two-atom entanglement and thermal entanglement in a generalized Jaynes-Cummings model
Authors: Xiang Shao-Hua  , Yang Xiong  , Song Ke-Hui  ,   怀化学院物理与电子信息科学系,怀化 418008
Published: December 2020

In this paper, we investigate twoatom entanglement in time evolution and the thermal entanglement in a generalized JaynesCummings model by means of concurrence. The result shows that the twoatom entangled state appears with periodicity, which decreases with increasing dipoledipole coupling between the two atoms. In a finite temperature, the concurrence decreases with increasing temperature, and the thermal entanglement vanishes in this JaynesCummings model when the system temperature reaches the critical temperature, which is proportional to the dipoledipole coupling strength of the two atoms. For typical experimental data, the critical temperature is on the order of 10-5K. In addition, there exists the quantum phase transition in this JaynesCummings model
Wavelength design for the 941nm high output power strained single-quantum-well semiconductor lasers
Authors: Xin Guo-Feng  , Chen Guo-Ying  , Hua Ji-Zhen  , Zhao Run  , Kang Zhi-Long  , Feng Rong-Zhu  , An Zhen-Feng  ,   (1)河北工业大学信息工程学院微电子所,天津 300130; (2)河北工业大学信息工程学院微电子所,天津 300130；中国电子科技集团公司第十三研究所光电专业部,石家庄 050051; (3)中国电子科技集团公司第十三研究所光电专业部,石家庄 050051
Published: December 2020

The eigenvalue equation of the step finite strained single quantum well is deduced from Schrdinger equation, the influence of the step width on first electron energy, first hole energy, the stimulated wavelength, and the influence of the first hole energy on stimulated wavelength are studied. The results indicate that, if the In content is large, the influence of the first hole energy on the stimulated wavelength should not be neglected. The calculated value by using this model is in accord with the experiment results.
Classification of chaotic time series data based on the average length of close orbits
Authors: Xia Heng-Chao  , Zhan Yong-Qi  ,   上海交通大学机械与动力工程学院,上海 200030
Published: December 2020

Based on recurrence plot (RP) of chaotic time series, this paper develops the definition of cross recurrence plot (CRP) and the average length of close orbits, which reflects the similarity of two time series and is used to classify time series. By analysing the Lorenz signals, we conclude that the average length is decreased with the decrease of the similarity of two orbits. We have used our method and the crossprediction error in the detection of ECG rhythm. The results show that both methods work for rhythm with different waveforms, but our method works better for rhythms with similar waveforms than the method of cross_prediction error.
Regular and chaotic motions of a single trapped ion interacting with standing laser pulses
Authors: Li Fei  , Hai Wen-Hua  ,   湖南师范大学物理系,长沙 410081
Published: December 2020

We have studied the secular motion of a single ion stored in a Paul trap and sub jected to a sequence of standing laser pulses. Through theoretical analyses and numerical calculations, we obtain an exact solution of the classical motion equa tion that describes time evolution of the system. By using the exact solution we have investigated regular and chaotic motions of the system. For a weakly trapp ed ion with small confining frequency, a critical condition under which the s ys tem goes into global chaos is found. The loss of stability caused by resonanc e is shown and a method for controlling the instability is established.
Study on the relation between the dielectric properties and lattice distortions in PZT ferroelectric tetragonal phase region
Authors: Zhang Duan-Ming  , Yan Wen-Sheng  , Zhong Zhi-Cheng  , Yang Feng-Xia  , Zheng Ke-Yu  , Li Zhi-Hua  ,   (1)华中科技大学［主校区］物理系,武汉 430074;湖北襄樊学院物理系,襄樊 441053; (2)华中科技大学［主校区］物理系,武汉 430074;华中科技大学激光技术国家重点实验室,武汉 430074
Published: December 2020

From thermodynamic theory of the lead zirconatetitanate(PZT) solid solution sy stem, we have got the basic equation between the dielectric constant εr a nd lattice distortion c/a in ferroelectric tetragonal phase region, and base d on the relative experimental data and logical deduction to physics image, we h ave established basic relations between εr and c/a. And then, from th e basic relations, we have studied in detail the physics image about lattice dis tortion c/a effect on the dielectric constant εr in ferroelectric tet ragonal phase region. A comparison with related experimental results indicates t hat the results of the basic relations are in good agreement with the conclusion s of the experiments. Finally, we have discussed the application range of the ba sic relations and the physics reason of relative warp out of application range. We would emphasize that the basic relations are essentially fitted to all perovs kite structure materials.
Probing the total density of states in a photonic crystal with different number density distributions of luminescent molecules
Authors: Liu Xiao-Dong  , Li Shu-Guang  , Xu Xing-Sheng  , Wang Yi-Quan  , Cheng Bing-Ying  , Zhang Dao-Zhong  ,   (1)燕山大学理学院，秦皇岛 066004; (2)中国科学院物理研究所光物理实验室，北京 100080; (3)中国科学院物理研究所光物理实验室，北京 100080;大连民族学院机电信息工程系，大连 116600
Published: December 2020

The dynamical characteristics of the spontaneous decay of a single excited atom or molecule depend strongly on its position within a photonic crystal (PC) and the relative orientation of its dipole and the electric field there. Measuring its dynamical characteristics of the spontaneous decay in a PC can only obtain the local density of states (DOS) in the PC, but cannot reflect the total DOS in the PC. It is found, theoretically, that using different number density distributions of luminescent molecules within the PC, one can probe the partial information or even all of the total DOS in the PC. In this paper, we separate, for the first time to our knowledge, the total DOS into two parts, DOS in the scatterer and DOS in the matrix of the Wigner-Seitz unit cell, according to their origin, and demonstrate that a special number density distribution of fluorescent molecules can reflect the total scatterers DOS or total matrix DOS or even both of them, i.e. the total DOS in the PC. This is meaningful in explaining and designing the experiments of prohibiting and enhancing the spontaneous emission of excited molecules.
The capacity study of fast plastics scintillator for x-ray energy
Authors: Guo Cun  , Xu Rong-Kun  , Lee Zheng-Hong  , Xia Guang-Xin  , Ning Jia-Min  , Song Feng-Jun  ,   中国工程物理研究院核物理与化学研究所，绵阳市919信箱212分箱 621900
Published: December 2020

This paper presents the special character of a new type of plastics sc intillator prepared for the diagnosis of the total xrays in Zpinch. The expe ri mental results in the laboratory of Beijing Synchrotron Radiation Facility (BSRF ) indicate that the scintillator has a characteristic of even energy respond in the energy region from 100eV to 1400eV, heavy restrain of visible light, fast de cay time of 6ns.
Scaled-energy spectroscopy of barium M = 0 Rydberg atoms in an electric field
Authors: Ni Ni  , Cao Jun-Wen  , Wang Chuan  , Zhan Ming-Sheng  ,   中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室，武汉  430071
Published: December 2020

Choosing the polarization of the laser,changing the wavelength of the excitation laser and the strength of an external electric field synchronously to keep scal edenergy constant,we have measured M=0 constant scaledenergy absorption spectra of barium Rydberg atoms at scaledenergy ε=-300.Fourier transfor med recurrence spectra were compared with the closedorbit calculation for hydr ogen atom in the uniform approximation.The positions of experimental recurrence peaks fit well the theoretical ones,but the peak strengths differ remarkably,esp ecially in the region of scaledaction larger than 5.This may indicate a large effect of the barium core and the electron correlation on the electron dynamics.
Quantization of dissipative mesoscopic capacitance coupling circuit
Authors: Song Tong-Qiang  ,   宁波大学物理系，宁波 315211
Published: December 2020

By means of canonicalization transformation, we study the quantization of dissi pative mesoscopic capacitance coupling circuit, and discuss the quantum fluctuat ions of charges and generalized currents in the system.
The generalized M2-factor and coherent-mode decomposition of truncated flat-topped beams
Authors: Zeng Qing-Gang  , Wen Qiao  , Zhang Bin  ,   四川大学电子信息学院，成都 610064
Published: December 2020

By using the definition of generalized secondorder moments and co m plex Gaussian functions expansion of rectangular function, the analytical expres sions for the generalized M2factor and mode coherence coefficients of th e new m odel of flattopped beams introduced by Li have been derived. The mode correlat i on, mode structure, and coherentmode decomposition of flattopped beams have be en analyzed. Theory of the coherentmode decomposition of truncated flattoppe d beams is built.
Influence of dark irradiation on transition process from self-defocusing to self-focusing in LiNbO3:Fe crystals
Authors: Huang Chun-Fu  , Guo Ru  , Liu Si-Min  , Shu Qiang  , Gao Yuan-Mei  , Wan Da-Yun  , Liu Zhao-Hong  , Zhang Xiao-Hua  , Lu Yi  ,   (1)南开大学物理学院,天津 300071; (2)天津理工学院自动化系，天津 300071
Published: December 2020

We have studied the dynamic propagation of an optical beam from selfdefocusing to selffoc using in photovoltaic photorefractive crystals LiNbO3:Fe in the framework of a t wodimensional band transport model. The results show that dark irradiation pla ys an important part in the transition process. The transition occurs only when th e normalized dark irradiation is very small. We discuss also the influence of py roelectric effect on the transition process.
A study on monocycle optical pulse generation by crossed phase modulation in a single-mode fiber
Authors: Xiang Wang-Hua  , Chen Xiao-Wei  , Tan Bin  , Zhang Gui-Zhong  ,   天津大学精密仪器与光电子工程学院，光电信息技术科学教育部重点实验室，天津 300072
Published: December 2020

In this paper, principles for monocyclic pulse generation by crossed phase modulation in silicon fibers are introduced. The effect of pulse parameters on the spectra broadening is analyzed in detail. For an actual example, split-step Fourier method is performed to verify the theoretic analytic results. Finally, an ultrabroad-band spectrum ranging from 200 to 1000THz and its ideally compressed pulse is achieved.
Study on pulse compression in dispersion-decreasing fibers
Authors: Liu Jian-Hui  , Ding Yong-Kui  , Tan Li  , Hu Zhi-Yong  , Li Shi-Chen  ,   天津大学精密仪器与光电子工程学院，天津 300072
Published: December 2020

This paper studies the adiabatic soliton compression of pulses in dispersion dec reasing fibers(DDF).We indicate that although high quality compressed pulse coul d be achieved from ps fundamental soliton by using DDF with linear profile,the r equired fiber length is too long to be useful.As a result,higher order soliton c ompression in DDF is proposed to achieve large compression factor and high quali ty compression with relatively short fiber lengths.
Spectroscopic properties of Er3+-doped heavy metal oxyfluoride bismuth silicate glasses
Authors: Ma Hong-Ping  , Xu Shi-Qing  , Jiang Zhong-Hong  ,   (1)浙江科技学院机电系，杭州 310012; (2)中国科学院上海光学精密机械研究所，上海 201800
Published: December 2020

The absorption spectra, fluorescence spectra, fluorescence lifetime and thermal stability of Er3+doped (50x)SiO2xBi2O350PbF2 (x =0, 3, 5, 8, 10, 13, 15 mol%) glasses were investigated. The intensity paramet ers Ωt (t=2,4,6) were calculated by JuddOfelt theory, and the stimulate d emission sectionsections of 4I13/2→4I15/2 transitio ns were calculated by McCumber. The results showed that the FWHM value is relate d to the Ω6 parameter, and the larger the Ω6 parameter, the broade r the FWHM. Compared with other glass hosts, the gain bandwidth property of Er 3+doped SBP3 glass is close to those of tellurite and bismuth glasses, and much greater than those of silicate, a phosphate and germanate glass, which sho ws that Er3+doped heavy metal oxyfluoride bismuth silicate glasses can b e used as host materials for broadband optical amplifier.
A study on periodic poling of different compositions of MgO:LiNbO3
Authors: Chen Yun-Lin  , Guo Juan  , Liu Xiao-Juan  , Lou Ci-Bo  , Chen Shao-Lin  , Xu Jing-Jun  , Zhang Wan-Lin  , Kong Yong-Fa  , Zhang Guang-Yin  ,   南开大学物理科学学院,天津 300071
Published: December 2020

LiNbO3 crystals doped with different amount of MgO have been produced using vapor transport equilibration technique. The poling characteristics of the crystals with different MgO doping levels have been investigated. The switching field and the spontaneous polarization Ps of the crystals were expressed as functions of crystal stoichiometry and Mg content. The switching field for the domain reversal in the near stoichiometric crystal with ［Li］/［Nb］=0.973 doped with 2.0mol.% MgO was 1.8kV/mm. This is about one twelfth of the switching field for the congruent crystal, and the pattern of the periodic domain in the crystal is better than in the congruent and stoichiometric crystal.
Fractal structure of water molecular gels formedby the aggregation of organogelators
Authors: Wang Li  , Li Jian  , Yang Ya-Jiang  ,   华中科技大学化学系,武汉 430074
Published: December 2020

Water molecular gel is a kind of soft condensed systems. It was formed by the aggregation and self-assembly of gelator 4,4′-bisstearylamide diphenyl ether (BSADE) which makes water into gelation at very low concentration in water. Its microcosmic morphology, thin fibre-like aggregate, was observed by transmission electron microscope(TEM) of the gels. By digitalized treatment of TEM photos, the structure of three-dimensional networks of gels shows a typical fractal characteristic. The fractal dimension D of the gels was calculated by the methods of Sandbox and density-density correlation function under the C++ program. The fractal dimension D calculated by the two methods is in the range of 1.814—1.977. Through the fractal theory, the aggregation process of gelator and the fractal characteristic of the gels was discussed. Further investigation by small angle x-ray scattering indicated that the fractal scale of the gels is between α=1nm and ε=40nm. and fractal characteristic was shown in a larger area. Its fractal dimension is 1.9, which is in agreement with the results from TEM method.
Interactions between two Y-periodic solitons in the（2+1）-dimensional Sawada-Kotera equations
Authors: Ruan Hang-Yu  ,   宁波大学物理系，宁波 315211;浙江大学近代物理中心，杭州 310027
Published: December 2020

The exact solutions of the (2+1)dimensional Sawada-Kodera(SK) equation are presented by using the bilinear method.The N breather solutions,the solution to describe the interaction between a line solition and a y periodic soliton and the solution to express the interaction between two y periodic soliton are included in the exact solutions.Detailed behaviors of interactions between two y periodic solitons are illustrated both analytically and graphically.For SK equation,the value of interactive constant can only be taken in some range.We can only obtain the repulsive interaction that keeps the shapes of soliton unchanged.
Integrability aspects of solitons’ coupled equation in multi-wavelength system
Authors: Li Qi-Liang  , Zhu Hai-Dong  , Tang Xiang-Hong  , Li Cheng-Jia  , Wang Xiao-Jun  , Lin Li-Bin  ,   杭州电子工业学院通信工程学院，杭州 310037;四川大学物理科学与技术学院，成都 610064
Published: December 2020

We have studied the integralility aspects of solitons' coupled equation in a multi-wavelength system with Lax pair, by using Hirota bilinearization, we obtain one-soliton and two-solitons solutions.
Explicit travelling wave solutions for Zakharov equations
Authors: Zhao Chang-Hai  , Sheng Zheng-Mao  ,   浙江大学物理系，杭州 310027;江苏南通师范学院物理系，南通 226007
Published: December 2020

In this paper, several new traveling wave solutions for Zakharov equations are obtained by using bi function method and Wu elimination method, which include periodic traveling wave solutions and solitary wave solutions. Their physical meaning is also discussed.
A simple method for solving a class of nonlinearly coupled evolution equations in higher dimensional space
Authors: Li De-Sheng  , Zhang Hong-Qing  ,   大连理工大学应用数学系，大连 116024;沈阳工业大学理学院，沈阳 110023
Published: December 2020

In this paper,a class of nonlingearly coupled evolution equations in higher dimensional spaces is reduced to a simple nonlinear evolution equation in lower dimensional spaces by using a simple transformation,and then we can easily obtain the solutions of the original equations by appling existing method to the simple nonlinear evolution equation.
Remarks on “Lewis-Riesenfeld phase” and quantum geometric phase
Authors: Li Hua-Zhong  ,   中山大学高等学术研究中心及物理系，广州 510275
Published: December 2020

Some misconceptions in an article on the so called “Lewis phase” and quantum geometric phase in Chinese are critically reviewed. We point out the wrong statements given in the paper published in College Physics 21 23,written in Chinese.
The research of properties of the quantum conditional amplitude operator
Authors: Zhang  De-Xing  ,   贵州大学物理系，贵阳 550025
Published: December 2020

This paper analyzes the properties of the quantum conditional amplitude operator.This operator plays a role similar to that of the conditional probability in classical information theory.One argues that the spectrum of the conditional operator that characterizes a quantum bipartite system is invariant under local unitary transformations,and shows its inseparability.It is proven that the conditional amplitude operator of a separable state cannot have an eigenvalue exceeding unity.A related separability condition based on the non-negativity of the von Neumann conditional entropy is obtained.
Bound states of Klein-Gordon equation for ring-shaped non-spherical harmonic oscillator potentials
Authors: Lu Fa-Lin  , Chen Chang-Yuan  ,   盐城师范学院物理系，盐城 224002
Published: December 2020

By using the ordinary method of variable separation,the bound states of Klein-Gordon equation of the ring-shaped non-spherical harmonic oscillator with equal scalar and vector potentials are solved. The normalized angular wave function expressed in terms of the universal associatedLegendre polynomial and the normalized radial wave function expressed in terms of the confluent hyper-geometric function are presented. The exact energy spectrum equations are obtained.
A study about the energy-momentum tensor of pure gravitational field part of matter
Authors: Lou Tai-Ping  ,   东北大学材料与冶金学院，沈阳 110004
Published: December 2020

In this paper,the existing forms of matter is supposed to be divided into two parts, one is the pure matter part,and another is the pure gravitational field part.The two parts of existing forms of matter are corresponding to their energy-momentum tensors,respectively.So the total energy-momentum tensor of matter can be expressed as Tμν=T(Ⅰ)μν+T(Ⅱ)μν,where T(Ⅰ)μν and T（Ⅱ）μνare energy-momentum tensors of pure matter part and pure gravitational field part,respectively.By analogy with the electromagnetic theory,a vector is defined as:ωμ≡-c2gμ0/g00,and an antisymmetric tensor is defined as:Dμν=ωμ/xν-ων/xμ，so the energy-momentum tensor of the pure gravitational field part of the matter is supposed to be T(Ⅱ)μν=(DμρDρν-gμνDαβDαβ/4)/4πG.The gravitational field equation which contains pure gravitational field part of matter can be expressed by Rμν-gμνR/2=8πG(T(Ⅰ)μν+T(Ⅱ)μν)/c4.The theory of the gravitational field which contains the energy-momentum tensor of pure gravitational field part of matter can be used in an isolated globular symmetry for pure matter with mass M ,which is time-independent,and the line-element of time-space for the out side of globular symmetry of pure matter can be obtained by ds2=-(1-m/r)-2dr2-r2dθ2-r2sin2θdφ2+(1-m/r)2c2dt2，where m=GM/c2.
Acceleration of a kind of null geodesic
Authors: Tian Gui-Hua  , Zhao Zheng  ,   北京邮电大学理学院，北京 100876;北京师范大学物理系，北京 100875
Published: December 2020

When a null geodesic γ0,orthogonal to a space-like two-surface φ,is from φ to q with a point r∈(φ,q)conjugate to φ along γ0(λ),there will be a variation of γ0(λ) which will give time-like curves from φ to q.This is a well-known theory in the famous bood.When the variation vector is not a generalized Jacobi field on the null geodesic γ0,the acceleration of these time-like curves approaches infinity as the time-like curves approach the null geodesic.
Quantum thermodynamical properties of the slowly changing nonstationary Kerr-Newman black hole
Authors: Wang Gang-Zhu  , Wang Ji-Long  ,   太原理工大学应用物理系，太原 030024
Published: December 2020

Introducing the notion of the local thermal equilibrium,the Hawking effect and the entropy of a nonstationary Kerr-Newman black hole whose metric changes slowly are studied by the method of Damour-Ruffini and the thin film model.First,we obtain the Hawking radiation temperature and the thermal spectrum formula,and show that the Hawking temperature depends on the time and the location on the event horizon,the thermal spectrum is a quasi-black-body's thermal spectrum.Second,we calculate the black hole entropy,which is just the Bekenstein-Hawking entropy with the same geometrical cutoff relationship as in the static and spherical case.The results show that the temperature of the black hole is a local quantity,and the entropy of the nonstationary black hole is also proportional to the horizon area as in the case of stationary black holes.
Research on circuitry realization and synchronization of Chen chaotic systems
Authors: Li Shi-Hua  , Cai Hai-Xing  ,   东南大学自动控制系，南京 210096
Published: December 2020

Based on the work in Int. J. of Bifurcation and Chaos vol.12(2002)1423,we address the circuitry realization problem of Chen chaotic system.We derive available circuit parameters with which we simulate the circuit on the simulation softwareElectronic Workbench.After realizing the Chen system in the circuit,we observe the chaotic figure on the oscillograph.Employing the synchroniation method using single variable coupling feedback,we conduct the synchronization experiments and obtain the parameter range for controlling the synchronization between two Chen's systems.
The arbitrary order implicit multistep exponential time differencing method and its application for nonlinear systems
Authors: Tang Chen  , Yan Hai-Qing  , Zhang Hao  , Liu Ming  , Zhang Gui-Min  ,   天津大学应用物理系，天津 300072;中国科学院力学研究所非线性力学国家重点实验室，北京 100080
Published: December 2020

The arbitrary order implicit exponential time differencing multistep method is proposed for nonlinear systems.We carry out the predictor_corrector method of exponential time differencing.When the method is applied to the nonlinear systems,the effect is admirable.The numerical results show that the accuracy of explicit exponential time differencing multistep method can be enhanced by implicit exponential time differencing multistep method,and the lather is highly accurate and computationally efficient.The exponential time differencing method has been developen and perfected by the present studies.
Frequency shift of laser pulse propagating in wakefield
Authors: Xu Han  , Chang Wen-Wei  , Yin Yan  ,   国防科技大学理学院,长沙 410073
Published: December 2020

When two ultrashort and ultrahigh laser pulses spacing an appropriate distance propagate through tenuous plasma, the second laser pulse will be compressed and shift to higher frequency because the anterior part of the pulse experiences the higher plasma density and propagates with lower group velocity while the rear part of the pulse experiences the lower plasma density and propagates with higher group velocity. The frequency shift of the second pulse in our PIC simulation is in good agreement with the theoretical predication. Furthermore, the optimum intervals between the two pulses is larger than that estimated with linear theory.
A self-adaptive bi-particle graph model for scientific collaboration
Authors: He Yue  , Zhang Pei-Pei  , Xu Tian  , Jiang Yu-Mei  , He Da-Ren  ,   扬州大学物理科学与技术学院，扬州 225002
Published: December 2020

This paper suggests a self-adaptive bi-particle graph model, which describes the collaboration network between the principal investigators and their assistants. The model considers the choices, strategies, competitions, and the induced evolutions of the principal investigators and their assistants as actors as well as the evolution of the whole network. The simulation results of all the different single-particle graphs obtained by different methods of projection show a good agreement with the statistical data of the collaboration between American mathematicians and neuroscientists during 1991 and 1998 That shows a self-adaptive complex network can selforganize to a small world and scale-free structure. This article also discusses the similarities and differences of the simulation results of the different projected single-particle graphs of the bi-particle graph.
Trapping stiffness measurement with brownian motion analysis method at low sampling frequency
Authors: Jiang Yu-Qiang  , Guo Hong-Lian  , Liu Chun-Xiang  , Li Zhao-Lin  , Cheng Bing-Ying  , Zhang Dao-Zhong  , Jia Suo-Tang  ,   量子光学与光量子器件国家重点实验室，山西大学物理电子工程学院，太原 030006;中国科学院物理研究所和凝聚态物理中心光物理实验室，北京 100080
Published: December 2020

The Brownian motion analysis is a preferable method to investigate the trapping stiffness of optical tweezers system because of its convenience and simplicity. However, there would be obvious deviation if the detector's response frequency or sampling frequency is low. Such problems are discussed and a solution is brought forward in this article.
Optimum thickness for laser induced thermoelectric voltage effect in high Tc superconductor and CMR thin film
Authors: Wang Chong  , Zhang Peng-Xiang  , Zhang Guo-Yong  ,   昆明理工大学光电子新材料研究所，昆明 650093
Published: December 2020

Based on the formula of the time dependence of laser-induced voltage in high Tc superconductor(HTSC) and collosal magneto-resistance (CMR) thin films, we have successfully deduced the function of the optimum thickness for producing largest laser-induced thermoelectric voltage. It is indicated that a direct proportional relationship between laser-induced thermoelectric voltage and the reciprocal of thickness does not correctly describe the situation. In fact, an optimum thickness must exist. This function provides the main factor of affecting the design for fast-time-response device. We have discussed the parameter of thin film influencing the optimum thickness, and compared it with experimental result.
A new method for measuring the dynamic behavior of the photorefractive nonlinear parameter
Authors: Liu Si-Min  , Zhao Hong-E  , Guo Ru  , Wang Da-Yun  , Gao Yuan-Mei  , Huang Chun-Fu  , Lu Yi  ,   南开大学物理学院，天津 300071
Published: December 2020

Based on the zscan method, we present a new method, the time-scan method, to measure the dynamic behavior of the photorefractive nonlinear parameter. We prove theoretically and experimentally that the new method is precise and feasible.
Calculation of wavelengths and oscillator strengths of transition 3d104s—3d94s4p for ions from MoⅩⅣ—RuⅩⅥ
Authors: Mu Zhi-Dong  , Wei Qi-Ying  ,   中国矿业大学理学院，徐州 221008
Published: December 2020

In this paper, we calculate the energy levels of configuration 3d-94s4p (J=1/2;3/2,Nth=1—4;1—7) for copper-like sequence ions from GeⅣ—RuⅩⅥ by HXR method. With the important effects, such as correlation effect, quantum electrodynamics (QED) effects and the other effects taken into account, we have made a systemisitic fit calculation for energy levels of ions mentioned above. We predict here the energy levels of configuration 3d-94s4p(J=1/2;3/2,Nth=1—4;1—7) for ions MoⅩⅣ—RuⅩⅥ.The wavelengths, oscillator strengths and probabilities of transition 3d-104s—3d-94s4p(J=1/2; 3/2,Nth=1—4; 1—7) are computed too.
Studies on the potential energy curves of hydride diatomic molecules using energy consistent method
Authors: Lu Guang-Hui  , Sun Wei-Guo  , Feng Hao  ,   四川大学原子与分子物理研究所，成都 610065
Published: December 2020

By using QCISD/6-311G（d）method, the ground state of SO-2, and its energy, harmonic frequencies, force constants have been calculated. The calculated results are in good agreement with the experimental ones. The analytical potential energy function of SO-2 has been derived based on the many-body expansion theory. The structure and energy of SO-2 can correctly reappear on the potential surface.
Photodissociation study of N2O+（A2Σ+） ions
Authors: Xu Hai-Feng  , Li Qi-Feng  , Zhou Xiao-Guo  , Dai Jing-Hua  , Liu Shi-Lin  , Ma Xing-Xiao  ,   中国科学院选键化学研究实验室，中国科学技术大学化学物理系，合肥 230026
Published: December 2020

Pure parent ions, N2O+, populated at X2Π(000), were prepared by (3+1) multiphoton ionization of jet cooled N2O molecules at 360.55nm, and then were excited to different vibrational levels of predissociative A2Σ+ state by another laser in the wavelength range of 275—328nm. The total released translational energies 〈ET〉 at different excitation energies were measured with a time of flight (TOF) spectrometer from the TOF broadenings of the NO+ fragment.The 〈ET〉value drops abruptly from ～8000cm-1 to ～1600cm-1 at excitation energy of ～32000cm-1.Further analysis shows that at the excitation energies below 32000cm-1, the dissociation channel is NO+(X1Σ+)+N(4S), and at the energies above 32000cm-1 a new channel, NO+(X1Σ+)+N(2D), is opened and replaces completely the N(4S) channel. The predissociation mechanism of the N2O+(A2Σ+) ions was discussed based on the experimental results.
Anisotropy analysis of strain-energy density in bcc-polycrystalline films
Authors: Zhang Jian-Min  , Xu Ke-Wei  ,   (1)陕西师范大学物理学与信息技术学院，西安 710062;西安交通大学金属材料强度国家重点实验室，西安 710049; (2)西安交通大学金属材料强度国家重点实验室，西安 710049
Published: December 2020

Based on elastic theory and yield strength formula of polycrystalline films, the strain-energy densities in differently oriented grains have been calculated for a bcc-polycrystalline film on a substrate. The results show that, (1) prior to yielding, the Fe and Ta are basically similar and with (100), (510), (410) and (511) oriented grains having the lowest strain-energy densities. For Cr, Mo, Nb and V, however, the four lowest strain-energy densities correspond to the grains with (111), (332), (322) and (211) planes oriented parallel to the film surface. For isotropic W, the strain energy density is independent of the grain orientation. (2) In all of yielded bcc-polycrystalline films, the four lowest strain energy densities correspond to the grains with (100), (111), (110) and (411) planes oriented parallel to the film surface. Considering strain energy minimization, we predicate that the grains with these orientations should be favorable in crystal growth successively.
Time-domain terahertz spectroscopy of (100) MgO and (100) LaAlO3 substrates
Authors: Hu Ying  , Zhang Cun-Lin  , Shen Jing-Ling  , X. C. Zhang  ,   首都师范大学物理系，北京 100037
Published: December 2020

THz(teraherz)properties of high-Tc superconductor substrates(100)MgO and (100)LaAlO3 are measured using time-domain spectroscopy at frequency range between 0.2 and 2 THz.The complex refractive index and dielectric function of the MgO substrate is independent of frequencies;those of LaAlO3 increase slightly with increasing frequency.We determine=3.46+i0.001 and=12.27+i0.06 for the MgO substrate and =4.78+i0.02 and =22.5+i0.2 for the LaAlO3 substrate at 1THz.The dielectric loss tanδ of both LaAlO3 and MgO substrate is less than 0.01The tanδ of LaAlO3 in nearly five times larger than MgO,but both of them are less than 0.01.
Theoretical and experimental study of new dark hollow beams
Authors: Zhang Lei  , Cai Yang-Jian  , Lu Xuan-Hui  ,   浙江大学现代光学仪器国家重点实验室光学研究所，光及电磁波研究中心，杭州 310027
Published: December 2020

A new mathematical model named hollow Gaussian beams (HGBs) is introduced to describe the dark hollow beam. The area of the dark region across the HGBs can be easily controlled by properly choosing the beam parameters. An analytical propagation formula for HGBs through paraxial optical system is derived. The evolution properties of the intensity distribution of HGBs in free space propagation are illustrated graphically using the derived propagation formula. By using matrix eigenvalues method, the laser cavity with diffraction optical elements, which can generate the dark hollow beams, was constructed. Dark hollow beams were realized in experiment and its intensity distribution properties in near field and far field were studied. The results derived from the experiment is coincident with those predicted by the theory. The dark hollow beams we have obtained can be used conveniently to analyze atoms manipulation and may provide a new method for atom cooling.
Study of self-erasing of recording process in Zn:Fe:LiNbO3 with the double-carrier four-trap model
Authors: Meng Qing-Xin  , Gong De-Wei  , Zhang Jian-Long  , Sun Xiu-Dong  ,   哈尔滨工业大学应用物理系，哈尔滨 150001
Published: December 2020

Photorefractive properties of Zn:Fe:LiNbO3 crystals were compared with Fe:LiNbO3 crystals. We described the photoconduction and diffraction efficiency as a function of incident light intensity. The self-erasing of recording process in the Zn:Fe:LiNbO3 crystal is observed. We found that the diffraction efficiency of the crystal increased to a saturation value and then decreased as recording time increases. The phenomena were explained by the double-carrier four-trap model. A suit able exposure schedule is chosen to realize the angle-multiplexed volume holographic storage. We have stored 30 images in the same volume of the crystal.
The frequency modulation effects of the probe field in three level Λ-system
Authors: Han Ding-An  , Guo Hong  , Sun Hui  , Bai Yan-Feng  ,   华南师范大学传输光学实验室,广州 510631
Published: December 2020

In this paper, the frequency modulation effect of the probe field in a three-level Λ system is discussed. According to the classical equation of motion for the electron, the dielectric susceptibility of the medium is not affected by frequency modulation. Based on the quantum theory and the frequency modulation term expanded in terms of Bessel functions, the effects of the frequency modulation of the probe field on the system are studied, in which, when the modulation frequency of the probe field is large enough, the periodical population evolutions exist in three levels. Meanwhile, the stationary susceptibility of the probe field is given.