bluuebunny/crossref_metadata_2025 huggingface dataset:
A new type of chaotic generator
Authors: Yu Si－Min  ,   广东工业大学自动化学院，广州　510090
Published: December 2020

A new type of chaotic generator is studied by constructing a three_segment piec ewise_linear odd function with variable breakpoint α. The characteristic of the chaotic generator presented is that when the breakpoint α varies in th e range of 0<α≤1, there is a route to chaos through period_doubling bifurcations, and the doubl e_ layer single spiral, single_layer single spiral, double_layer double spiral and single_layer double spiral chaotic attractors can be generated. In particular, the double-layer single spiral and double-layer double spiral are found in our circuit experiment for the first time so far as we know. The b ifurca tion diagram, Lyap unov exponents λ_1,λ_2,λ_3, maximal Lyapunov exponent λ_maxand the spectrum of the single_layer double spiral and double-layer double spiral are also investigated. The associated electronic circuit is designed and the experimental result is given, which is ver ified by computer simulation and circuit experiment.
The study of the effect of delay probability on mixed vehiclessensitive driving traffic flow model
Authors: Kuang Hua  , Kong Ling-Jiang  , Liu Mu－Ren  ,   广西师范大学物理与信息工程学院,  桂林　541004
Published: December 2020

Considering that the maximum velocities for different types of vehicles ar e not the same and drivers may adopt different randomization brake probabilities , we pro posed a one_dimensional sensitive driving cellular automaton model for mixed tra ffic flow based on the NS model. We presented the fundamental diagrams for diff erent parameters by using computer numerical simulation, which show that the flu x is h igher than that of the NS model and the SDNS model. Moreover, some complicated b ehaviors of the model such as the metastable state and the separation of phases are also observed. Compared with the real traffic, the characters of this model are shown and analyzed.
The coherent excitation property of a two-level atom w itha hyperfine structure in narrow band laser field
Authors: Wang Li－Jun  , Yu Hui-Ying  ,   清华大学工程物理系,北京　100084
Published: December 2020

In this paper the semi-classic theory of coherent excitation of a two-level atom was modified and applied to a two-level atom with a hyperfine structure. The im portant result of calculation is as follows: when the exciting laser power is la rge enough, due to the power broadening effect, a narrow-band laser can excite a two-level atom with a hyperfine structure effectively. So it is not necessary t o use a broad-band laser to guarantee excitation efficiency for an atom with hyp erfine split levels.
Study on Brillouin-Rayleigh scattering under Raman pum p*
Authors: Yun Peng  , Chi Rong-Hua  , Li Yi-Gang  , Lü Ke-Cheng  ,   南开大学物理学院,  天津　300071
Published: December 2020

We have experimentally studied the Brillouin-Rayleigh scat tering in dispersion compensation fibers under Raman pump of different po we rs, and analyzed the characteristics of output spectra and the variation of th e spectra with pump power in detail. Then, based on the known theoretical model of the first-order stimulated Brillouin scattering, we deduce the theoretica l model for multi-order Brillouin-Rayleigh scattering. By this model, we have ma de numerical simulation, and the results show that theory and experiment are consiste nt at lower pump power, but have great differences at higher pump power.Moreove r, we analyze carefully the differences between theory and experiment. Finally,from theoretical calculation and experimental results, we obtain the saturation charac teristics of Brillouin-Rayleigh scattering at higher pump power, so that we can easily explain the cause of flat multi-order Brillouin-Rayleigh scattering at a certain higher Raman pump power.
MOVPE growth of 1310?nm polarizationinsensitive strained quantumwell semiconductor optical amplifiers*
Authors: Ma Hong  , Zhu Guang-Xi  , Chen Si-Hai  , Yi Xin-Jian  ,   (1)华中科技大学电子与信息工程系，武汉　430074; (2)华中科技大学光电子工程系，武汉　430074; (3)华中科技大学光电子工程系，武汉　430074华中科技大学电子与信息工程系，武汉　430074
Published: December 2020

The compressivelystrained quantum wells, tensilestrained quantum wells and the combination of tensilestrained and compressivelystrained quantum wells were grown by metal organic vapor phase epitaxy, the materials properties were meas ured by photoluminescence spectra and x-ray doublecrystal diffraction. A polarizationinsensitive multiplequantumwell optical amplifier for 1310nm wavelength employing both compressively strained wells and tensilestrained wells in active region is reported. The amplifier was fabricated to ridge waveguide structure with 7° tilted cavity, the two facets were coated with antireflection thin films. The amplifier exhibited an excellent polarization insensitivity (less than 0.6dB) over the entire range of wavelength (1.28-1.34μm) and a fiber to fiber gain of 21.5B at bias current of 200mA.
Experimental study on the holographic reconstruction and prediction of semi free field
Authors: Bi Chuan－Xing  , Chen Xin－Zhao  , Chen Jian  ,   合肥工业大学动态测试中心，合肥　230009
Published: December 2020

The study on the holographic reconstruction and prediction of a semifree field is valuable for the practical applications of the acoustic holography technique. On the basis of the proposed holographic reconstruction and prediction method of semifree field in the inverse distributed source boundary point method,an experiment is carried out in a semifree field. The reconstructed and predicted results in the proposed method are compared with those in the conventional method. The influence of the reflected sound in the reconstruction procedure is analyzed, and the effectiveness and correctness of the proposed method are validated. In addition, considering the sensitivity of the system equations to the measurement errors of pressures on the hologram surface in the experiment, the truncated singular value decomposition method and the Tikhonov regularization method are adopted to stabilize the problem. By choosing the appropriate regularization parameters and filter factors, the influence of errors can be decreased to the least, and the reconstructed and predicted quantities of acoustic field and the reliability of the holographic images are improved.
The strain distribution of lowdimensional semiconductor materials
Authors: Zhou Wang－Min  , Wang Chong－Yu  ,   浙江工业大学机电学院，杭州　310032钢铁研究总院功能材料研究所，北京　100081
Published: December 2020

The stress and strain distributions of simplified and idealized two, one and zero dimensional semiconductor materials,i.e. quantum well, quantum wire and quantum dot are investigated based on the isotropic theory of elasticity, and the differences among the stress, strain and strain energy distributions for the materials are discussed. The results can help us to understand qualitatively the stress, strain and strain energy distributions of the more complicated shapes and structures of lowdimensional semiconductor materials.
Influence of thickness on charge storage and dynamic properties of nonpolar film electrets
Authors: Wu Xian－Yong  , Xia Zhong－Fu  , An Zhen－Lian  , Zhang Peng－Feng  ,   同济大学波耳固体物理研究所，上海　200092
Published: December 2020

In this paper, taking commercial Teflon FEP films of Du Pont Co. as an example, the influence of sample thickness on deposited charge density, the internal electrical field of film electrets charged at room and elevated temperatures, and on their bulk conductivity and c harge storage stability is discussed by means of heat pulse technique, measurement of isothermal surface potential decay and analysis of open circuit thermally stimulated discharge current spectra. The influence of the thickness on the shift of mean charge depth of the deposited charge layer under different temperature conditions is also investigated by the measurements of heat pulse technique in combination with conductivity glow curve. The results indicate that under the same charging conditions and with the decrease of the sample thickness, charge density increases, but at the same time charge storage stability is decreased gradually. Therefore, the charge storage capability and charge stability can be optimized by reasonably regulating the thickness of the sample.
Micromagnetic analysis of the magnetization reversal processes in Sm(Co,Cu,Fe,Zr)z magnets*
Authors: Chen Ren-Jie  , Rong Chuan-Bing  , Zhang Hong-Wei  , He Shu-Li  , Zhang Shao-Ying  , Shen  Bao-Gen  ,   中国科学院物理研究所磁学国家重点实验室，北京　100080
Published: December 2020

The influence of microstructure on magnetic properties of Sm(Co,Cu,Fe,Zr)z magnets is investigated by micromagnetic finite_element method. The demagnetization curves at different temperatures are also simulated. The calculated results show that the saturation polarization Js depends on the relative proportions of 2∶17 phase and 1∶5 phase. The coercivity and the maximum energy product increase with increasing 2∶17type cell size, while they decrease wi th increasing width of 1∶5type cell boundary. The coercivity analysis shows t hat the magnetization reversa l in Sm(Co,Cu,Fe,Zr)z magnets is mainly controlled by nucleation at cell bounda ry. The abnormal temperature dependence of coercivity is due to the fact that the cell boundary becomes less magnetic even nonmagnetic and the nucleation is difficult with increasing temperature.
Optical bistability in granular composite media at high temperatures*
Authors: Lu Xing-Zhong  , Gao Lei  ,   (1)苏州大学物理科学与技术学院,苏州　215006; (2)苏州大学物理科学与技术学院,苏州　215006 常州工学院理学院,常州　213002
Published: December 2020

Optical bistability has been investigated in granular metal-dielectric composite media at high temperatures. Based on Maxwell-Garnett approximation and the spe ctralrepresentation, we calculate numerically the electric field as a function of the applied electric field E２０,and thus the opticalbistability can be studied.We show that the width of optical bistability decreases with increasing temperature.Furthermore, we study the dependence of the refractive index and the extinction coefficient on the temperature.
The excited state upconversion of Pr(0.5):ZBLAN under two-color excitation*
Authors: Chen Xiao-Bo  , Cai Qing  , Wang Ce  ,   (1)北京玻璃研究院,北京　100062; (2)北京师范大学分析测试中心，应用光学北京市重点实验室,北京100875
Published: December 2020

This paper reports the excited-state upconversion of Pr(0.5):ZBLAN glass under two-color excitation. It is found that the fluorescence of upconversion-emiss ion spectrum is the same as that of common-emission spectrum. It is found also that there are three obvious peaks on upconversionexcitation spectrum under twocolor excitation, which corresponds to the 788.5nm 1G4→3P2,850.5nm 1G4→1I6,and 805.0nm 3H6→1D2 excited state absorpt ion transitions res pectively. The large 850.5nm peak of upconversion-excitation spectrum results from the large 1G4(Pr3+ )→1I6(Pr3+) (Pr3+) oscil lator strength f=23.04×10-6. It illustrates the excited state absorp tion upconve rsion from 1G4 level, especially the 1G4(Pr3+)→1I6(Pr3+) upconversion process is large. It results in the upcon version luminescence of Pr(0.5):ZBLAN under two-color excitation.
The effect of sputtering particle energy on surface characteristics of Mo thin films
Authors: Qi Hong- Ji  , Yi Kui  , He Hong- Bo  , Shao Jian- Da  ,   中国科学院上海光学精密机械研究所，上海　201800
Published: December 2020

Using the atomic force microscopy, we have studied the effect of sputtering particle energy on the growth and microstructures of Mo thin films prepared on borosilicate glass (BK7) substrates with ion beam sputtering technique. With specially designed fixture, all samples were prepared in the same run, which diminished the effect of multi-runs on the growth of thin films. Furthermore,the morphology of Mo thin films was studied quantitatively based on numerical analy sis. The morphology of Mo thin films is typically fractal, and the surface para meters of thin films such as fractal dimensions, lateral correlation length and interface width are all obtained. Compared with the thin films prepared under the screen grid voltages of 300 and 700V, the interface width and lateral correlation length of the thin films prepared under the screen grid voltage of 500 V show two times large difference. All the fractal dimensions of thin films are n ear 2 and the growth process of Mo thin films can be described using Mullins diffus ion model. Besides, by using the technique of Auger electron spectroscopy, the atomic concentrations can be obtained in the depth profile.
Exact solutions of nonlinear Shr?dinger equations
Authors: Pu Li-Chun  , Lin Zong-Bing  , Zhang Xue-Feng  , Wang Ben-Ju  , Jiang Yi  , Yan Tian-Yan  ,   攀枝花学院数理教学部,攀枝花  617000
Published: December 2020

A Maple language process is utilized to find the traveling wave accurate solutions and their restricting condition equation for nonlinear Schrdinger equations with coupling characteristic without any assumptions. The expressions are arbitrary and cover all coupling solutions and non-coupling solutions. The calculation and characteristic analysis for the coupling solutions can explain the coupling effect of traveling wave solition solutions of the helix chain movement model for the alpha-helix protein and reveal the direction in which the protein activation and function are increased and fixed. The research methods in this paper provide certain ways for obtaining the traveling wave accurate solutions of the coupling nonlinear differential equations.
Simulation of x-ray transmission through a capillary
Authors: Wu Peng-Ju  , Li Yu-De  , Lin Xiao-Yan  , Liu An-Dong  , Sun Tian-Xi  ,   北京师范大学射线束技术与材料改性教育部重点实验室，北京师范大学低能核物理研究所，北京市辐射中心，北京  100875
Published: December 2020

A ray-tracing theory for the X-ray transmission in a capillary is described based on which a calculation model is built. The transmission efficiency and intensity distribution curve through a capillary are numerically calculated. The simulation results are in good agreement with the experimental results and previous simulations.
Higher order Lagrange equations of holonomic potential mechanical system
Authors: Zhang Xiang-Wu  ,   陇东学院物理系，庆阳  745000
Published: December 2020

First, the theorem on energy of higher order velocity of the holonomic potential mechanical system is presented with on explaining of the physical meaning of energy of higher order velocity of the system. The general criterion of potential mechanical system is then presented. On this basis, the higher order Lagrange function is introduced,the higher order Lagrange equations of holonomic potential mechanical system are derived, and the higher order cyclic integral and the integral of higher order generalized energy of the system are obtained.
Using trial equation method to solve the exact solutions for two kinds of KdV equations with variable coefficients
Authors: Liu Cheng-Shi  ,   大庆石油学院数学系，大庆  163318
Published: December 2020

Trial equation method was applied to nonlinear evolution equations with variable coefficients. As examples, exact solutions for two kinds of KdV equations with variable coefficients were obtained. Some of these results were new.
Characteristics of the band structure in two-dimensional phononic crystals with complex lattices
Authors: Zhao Fang  , Yuan Li-Bo  ,   哈尔滨工程大学理学院，物理系，哈尔滨  150001
Published: December 2020

The band structure of two-dimensional phononic crystals with complex lattices is analyzed using the plane-wave algorithm in this paper. Phononic crystals composed of two-dimensional arrays of periodic aluminium alloy cylinders in air are calculated. Band structures of two types of complex lattices, the honeycomb and the Kagome lattices, are presented. The band structures of complex lattices and simple lattices are compared. It is concluded that compared with simple lattices, the band-gap of complex lattices are located at lower frequency fields. When the filling fraction is between 0.091 and 0.6046, the complex lattices have larger band gaps and gain an advantage over simple lattices. In addition, the gap map is introduced to illustrate the influences of the filling fraction on the number, the width and the limit frequency of the band-gap.
General WGHZ state and its disentanglement and probabilistic teleportation
Authors: Huang Yong-Chang  , Liu Min  ,   (1)北京工业大学应用数理学院理论物理研究室，北京  100022; (2)北京工业大学应用数理学院理论物理研究室，北京  100022;China Center of Advanced Science and Technology (World Laboratory),Beijing  100080
Published: December 2020

A general WGHZ state is given, different entanglement W states are deduced by means of the general WGHZ state, different disentanglement conditions are obtained. When taking different complex coefficients of the general WGHZ state as zero, there are different disentanglements, and different W states and different Bell basic vectors are achieved. The above disentanglement results agree with the results obtained from the usual disentanglement condition of decomposable property of density matrices. By constructing a 5×5 diagonal projection transformation matrix, the problem of the recovery of state distortion is salved when using general entanglement channels and not introducing an accessorial state, and the diagonal projection transformation matrix UM is different to that of the other references and is a direct transformion matrix. Furthermore, the problem of probabilistic teleportation of a general WGHZ state is solved without introducing an accessorial state using the general entanglement channels. The diagonal projection transformation matrix method developed in this paper may be directly generalized to probabilistic teleportation of general entanglement states.
Quantum fluctuation in the time-dependent linearly driven degenerate parametric amplification
Authors: Zhao Chao-Ying  , Tan Wei-Han  ,   上海大学物理系，上海  200444
Published: December 2020

A systematic theory of quantum fluctuation in the time-dependent linearly driven parametric amplification is developed. At first, a time-dependent linearly driven Fokker-Planck equation for the degenerate optical parametric amplification system is deduced when the pump depletion is considered, and then the quantum fluctuation below or near the threshold is evaluated, which is in agreement with that obtained by the linear theory or perturbation expansion near the threshold. Above the threshold, the short-time behavior of our solution is close to the linearization approximation; however, with the increase of interaction time τ, the long-time behavior of our solution shows that the squeezing is quite different from the linear theory.
A fast algorithm for generalized predictive control and synchronization of Hénon chaotic systems
Authors: Liu Fu-Cai  , Liang Xiao-Ming  ,   燕山大学电气工程学院自动化系,秦皇岛  066004
Published: December 2020

A kind of generalized predictive control and synchronization algorithm with terminal sliding model equation restriction for Hénon chaotic system is proposed. This algorithm combines the generalized predictive control with sliding-model control which has been applied to Hénon chaotic systems, and the soft coefficient to input signal, in which the inverse matrix does not require calculation. The method needs smaller computer memory and the computational speed is higher. The ability of tracking the reference signal and restraining the parameter perturbation and stochastic disturbance are improved. Simulated results show the effectiveness and speed of this algorithm.
Optimization of scaled probabilistic cleaning methods
Authors: Jiang Ke-Yu  , Cai Zhi-Ming  ,   海军工程大学电子工程学院，武汉  430033
Published: December 2020

The scaled probabilistic cleaning method is one of nonlinear noise reduction methods for chaotic time series, whose calculation quantity and needed memory volume increase exponentially with the number of reference points and the embedding dimension because of the joint processing of all data points in phase space. An optimized method, which modifies the estimation of forward probabilities and transition probabilities is proposed, and the computing workload is reduced to about 0.27 times that of the original method without degradation in noise reduction performance. The implementation of the method for the long time series also reduces the needed memory size.
Cellular automaton traffic flow model considering intelligent transportation system
Authors: Ge Hong-Xia  , Zhu Hui-Bing  , Dai Shi-Qiang  ,   (1)上海市应用数学和力学研究所，上海大学，上海  200072; (2)上海市应用数学和力学研究所，上海大学，上海  200072;宁波大学建筑工程与环境学院，宁波  315211
Published: December 2020

A novel cellular automaton model for traffic flow on highway is proposed considering Intelligent Transportation System (ITS). Based on the Nagel-Schreckenberg model (NS for short), it includes effective gap and brake light. Moreover, a novel concept about the variable security gap is introduced. The simulation shows that the road capacity of the modified ITS cellular automaton model is higher than the measured data on certain highway, further indicating the important role of ITS,enlarged traffic flow and suppressed traffic jam. The mixed traffic flow related to two different vehicles' velocity is studied. The simulation shows even few slow vehicles will lead to drastic decrease of traffic flow, which demonstrates the necessity to implement strictly special fast lane.
Experimental research on the sensitivity of wavelength modulation by signal processing
Authors: Shao Jie  , Gao Xiao-Ming  , Yuan Yi-Qian  , Yang Yong  , Cao Zhen-Song  , Pei Shi-Xin  , Zhang Wei-Jun  ,   (1)中国科学院安徽光学精密机械研究所国家八六三计划大气光学重点实验室,合肥  230031; (2)中国科学院安徽光学精密机械研究所国家八六三计划大气光学重点实验室,合肥  230031;中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥  230031; (3)中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥  230031
Published: December 2020

We present a signal-processing system developed for enhancing the sensitivity of absorption measurement based on tunable diode laser wavelength modulation spectroscopy. A signal-to-noise ratio enhancement of an order of magnitude was observed when digital signal-processing algorithms were applied to wavelength modulation spectrometers in the near-infrared，at the same time a new spectra was found by observation of CO2 near 1.53 μm. These algorithms include digital low-pass filters, multiple averages, and a least squares fit. Digital signal processing has a practical advantage over other noise suppression techniques because it is easy to implement and adapt able to all experiments.
A high sensitive fission neutron detector system with a lead slot collimator
Authors: Ouyang Xiao-Ping  , Li Zhen-Fu  , Wang Qun-Shu  , Huo Yu-Kun  , Ma Yian-Liang  , Zhang Qian-Mei  , Zhang Guo-Guang  , Jin Yu-Ren  ,   (1)复旦大学现代物理研究所，上海  200433; (2)清华大学工程物理系，北京  100084;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

A fission neutron detector system with frontward-extended lead slot collimator has been developed and tested. By designing the slot collimator and developing large area PIN detectors as well as large area fissionable target with thin Be backing, this detector system can reach high neutron sensitivities up to 10-16C·cm2, which is about 4-5 orders of magnitude higher than that of existing fission detectors，and high n/γ　discrimination ratio up to 30.
Temperature measurement from the Raman spectra of porous silicon
Authors: Bai Ying  , Lan Yan-Na  , Mo Yu-Jun  ,   (1)河南大学物理与信息光电子学院，开封  475001; (2)河南大学物理与信息光电子学院，开封  475001;南通大学理学院，南通  226007
Published: December 2020

Raman spectra of porous silicon are obtained using 457.5nm laser line, from which some relations between peak parameters and laser powers are obtained. Our previous theoretical research demonstrated that the increase of laser power leads to the increase of local temperature, and this results in the shrink of local size which gives rise to the variation of a series of peak parameters. In this article we discuss and calculate in detail the influence of laser power on the local temperature of porous silicon, which set the experimental basis for the quantitative measurement of temperature utilizing Raman spectrum.
A novel beam-splitter for surface wave-guided atoms or molecules
Authors: Ji Xian-Ming  , Yin Jian-Ping  ,   (1)光谱学与波谱学教育部重点实验室，华东师范大学物理系，上海  200062; (2)南通大学理学院，南通  226007;光谱学与波谱学教育部重点实验室，华东师范大学物理系，上海  200062
Published: December 2020

We propose a new scheme to form a surface Y- or X-shaped beam splitter for optically wave-guided atoms (or molecules) and its Mach-Zehnder interferometer by using the combination of a binary π phase plate and a micro-cylindrical lens. The physics idea and basic principle of our beam splitter are introduced, and the analytic relationships between the intensity distribution (or the intensity gradient, or the splitting distance, and splitting-path width) and the parameters of our optical system are derived and discussed. The potential applications of the beam splitter and its experimental feasibility are discussed. Our study shows that the design is novel and the scheme is simple, and it can be used to construct various integrated atom- (or molecule-) optical elements with surface micro-structures, and even to form some all-optically integrated atom (or molecular) chips.
Study of 46.8MeV p+12C inelastic scattering
Authors: Gu Yun-Ting  , Feng Lu-Yan  , Tao Jun-Quan  , Huang Tian-Heng  , Luo Chun  , Ma Wei-Xing  ,   (1)广西大学物理科学与工程技术学院,南宁  530004; (2)中国科学院高能物理研究所,北京  100049
Published: December 2020

The inelastic scattering of 46.8MeV antiproton by 12C leading to the excitation of one normal parity T=0 levels is studied in the framework of Glauber model. The transition densities obtained from fitting to the electron scattering data and the three annihilation potentials derived from analysis of　p—p　scattering data are used in the calculation. The inelastic angular distribution for exciting the lowest normal parity T=0 states in 12C at 4.44MeV (Ｊπ＝２＋) by 46.8MeV antiproton are calculated by selecting potential parameter suitably. The results are seen to be in fairly good agreement with the available experimental data. The results are given by comparing the elementary two-body amplitudes.
Theoretical study of cross sections of excitation and ionization for electron-ion impact in average-atomic model
Authors: Tian Ming-Feng  , Meng Xu-Jun  , Zhu Xi-Rui  , Jiang Min-Hao  , Wang Zhi-Gang  ,   北京应用物理与计算数学研究所，计算物理实验室，北京8009信箱  100088
Published: December 2020

By using a distorted-wave Born exchange approximation method in averaged-atomic model, we calculated the direct excitation and direct ionization cross sections of several ions in plasmas. The ionization cross sections of ions at different temperatures or different plasma densities are systematically studied. It is found that due to the shift of the energy levels produced by the effects of the temperature and the density of plasma, the ionization cross sections of ions in plasmas are rather different from those of free atoms.
The effect of mass center motion on a two-level atom emission spectrum
Authors: Guo Hong  , Zhao Li-Yan  ,   (1)华中师范大学物理科学与技术学院，武汉  430079; (2)华中师范大学物理科学与技术学院，武汉  430079；中国科学院武汉物理与数学研究所，武汉  430071
Published: December 2020

The emission spectrum of a two-level atom in a harmonic trap is studied. It is shown that atomic motion do not affect the atomic spectrum phase sensitivity when there is no correlation between atomic mass center motion and the field. With the increase of the average energy of atomic center motion, the peaks move towards each other, their heights change with the state of the field and atomic motion. When there is correlation between atomic mass center motion and the field, the atomic spectrum becomes insensitive to the relative phase between the field and the atomic dipole. Under certain conditions, there are fewer peaks, and they become higher and narrower.
Scheme for quantum information processing via Λ-type atoms interacting with bimodal cavity field
Authors: Song Ke-Hui  ,   怀化学院物理与电子信息科学系，怀化  418008
Published: December 2020

Some schemes for the entanglement generation of two and three distant cavity-fields and the distant transfer of a qubit atomic state and atomic entangled state are presented. The realization of entanglement swapping without measurement on Bell basis vectors and the operation of swap gate are proposed. These schemes are all based on Λ-type atoms interacting with bimodal under one-photon detuning and two-photon resonance. Finally, a discussion of experimental feasibility is given.
Group velocity self-matching in noncollinear optical parametric generation with a type-Ⅰ phase-matched BBO crystal
Authors: Ma Jing  , Zhang Ruo-Bing  , Liu Bo  , Zhu Chen  , Zhang Wei-Li  , Zhang Zhi-Gang  , Wang Qing-Yue  ,   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（天津大学），天津  300072
Published: December 2020

Noncollinear parametric superfluorescence (NPS) is obtained in the visible regio n by pumping a type-Ⅰ phase-matched BBO crystal with the second harmonic of an amplified Ti:sapphire laser at 1kHz repetition rate. The variation of the noncol linear angle and the wavelength at the peak intensity of the NPS with the phase- matched angle is studied, and the variations of the group velocity mismatch (GVM ) with the noncollinear angle and the phase-matched angle in the three-wave inte raction is calculated theoretically. The results indicate that the type-Ⅰ phase -matched NPS ring is centrosymmetric with respect to the pump beam on the observ ation screen. Along the NPS direction at the peak intensity, the GVM is minimal and the effective interaction length is maximal for the three waves. The angular distribution of the NPS intensity is ascribed to phase velocity and group veloc ity self-matching among interacting pulses. The theory and the experiment provid e an ideal geometrical model for reducing the GVM between three waves, and provi de a theoretical guidance and experimental verification for obtaining parametric pulses with higher gain and shorter duration in femtosecond optical parametric amplification.
PBG structures of two-dimensional magnetic photonic crystals in square lattice
Authors: Che Ming  , Zhou Yun-Song  , Wang Fu-He  , Gu Ben-Yuan  ,   (1)首都师范大学物理系,北京  100037; (2)中国科学院物理研究所,北京  100080
Published: December 2020

Photonic band gap(PBG) structures of the two-dimensional magnetic photonic crystals (MPCs) are calculated by use of the plane-wave expansion method. The MPCs consist of magnetic pillars in rectangular, square, hexagonal and circular shapes, respectively embedded in dielectric medium in a square lattice. The optimal MPC samples that possess the largest gap-mid gap ratio for each type of MPC are obtained by scanning the three parameters(permeability, filling factor and rotating angle). The changes of the PBG structures are investigated when varying independently each parameter and fixing the others. Calculated results show that the frequency in the middle of the PBG hardly changes with the variation in filling factor or rotating angle, but decreases monotonicly with the increase of the per meability. The PBG width increases to a top value and then decreases with the in crease of each parameter.
Numerical simulation of filamentary discharge controlled by dielectric barrier at atmospheric pressure
Authors: Zhang Yuan-Tao  , Wang De-Zhen  , Wang Yan-Hui  ,   三束材料改性国家重点实验室，大连理工大学物理系，大连  116024
Published: December 2020

The spatio-temporal evolution of filamentary discharge in dielectric barrier dis charge at atmospheric pressure is studied. A two-dimensional model was solved wi th uniform initial conditions. The simulation results reveal that the breakdowns take place continuously at different positions and gradually spread all over th e discharge space. It is found that under certain conditions the splitting and u niting of filaments can occur, which has been observed in experiments. The split ting of filaments leads to the generation of new filament and the uniting reduce s the number density of filaments in discharge space. The simulation shows that the charges on barrier surface play a dominant role in determining the global sp atio-temporal evolution of filamentary discharge.
Thermal shock effect on diamond-like carbon thin films induced by pulsed-laser
Authors: Niu Yan-Xiong  , Huang Feng  , Duan Xiao-Feng  , Wang Yue-Feng  , Zhang Peng  , He Chen-Juan  , Yu Ye  , Yao Jian-Quan  ,   (1)解放军军械工程学院光学与电子工程系,石家庄  050003;天津大学精密机械与光电子工程学院，光电信息技术科学教育部重点实验室,天津  300 072;中国科学院物理研究所光物理实验室,北京  100080; (2)解放军军械工程学院光学与电子工程系,石家庄  050003;中国科学院物理研究所光物理实验室,北京  100080; (3)天津大学精密机械与光电子工程学院，光电信息技术科学教育部重点实验室,天津  300 072; (4)中国科学院物理研究所光物理实验室,北京  100080
Published: December 2020

When high power laser irradiates the infrared imaging system, the system will be injured or destroyed. The damage to the systems varies for different laser wavelengths. The infrared windows are generally coated with diamond-like carbon(DLC) thin films to protect itself and improve the permeation rate. When the incid ent laser's wavelength lies outside the infrared system response wave band, lase r destroys the DLC films firstly. The DLC films' damage mechanism induced by pul sed laser is studied with the 1.06μm laser. The thermal shock effect model of D LC films is proposed. The temperature and stress distributions are deduced throu gh solving the thermal conduction equation and stress-balance equation. The theo retical analysis shows that thermal stress fracture dominants in the damage mech anism. When the irradiation energy density is E0=100mJ·cm-2 , the pressu re on the surface of DLC films at about 40μm from the center of laser facula ex ceeds the rupture intensity, the film will break and peel off. The theoretical a nalysis matches the experimental results basically, and the correctness of the t hermal shock effect model is confirmed.
Modeling analysis of gradient-index coatings prepared by reactive magnetron sputtering
Authors: Shen Zi-Cai  , Shao Jian-Da  , Wang Ying-Jian  , Fan Zheng-Xiu  ,   (1)中国科学院上海光学精密机械研究所,上海  201800; (2)中国科学院上海光学精密机械研究所,上海  201800;中国科学院研究生院,北京  100039
Published: December 2020

The formation mechanism of gradient-index coatings by reactive magnetron sputtering is discussed. A practical modeling of gradient-index coatings is propose d, the relationship between refractive index of coatings and pressure of reactiv e gas is established. Next, we discussed the changing rule of partial-pressure o f reactive gas with time requivcd for obtaining a desired refractive index of g radient coatings under specific deposition conditions. A linear coating is tak en as example to illustrate how to get the relationship between partial-pressure of reactive gas and time.
Effect of micropore on hydrogen adsorption of single walled carbon nanotubes
Authors: Zheng Hong  , Wang Shao-Qing  , Cheng Hui-Ming  ,   沈阳材料科学国家（联合）实验室，中国科学院金属研究所，沈阳  110016
Published: December 2020

Using grand canonical ensemble Monte Carlo method,the effect of micropores,mainly the hollow cores of single-walled carbon nanotubes(SWNTs) and the interstitial channel among SWNTs,on the hydrogen adsorption of SWNTs was studied.Comparing with experimental observations,it was found that the hollow cores of SWNTs are the dominant sites for hydrogen adsorption,The overlap and efficiency of the adsorption potential inside a SWNT were analyzed,and it was found that the hydrogen adsorption capacity of the SWNTs is improved when the diameter of the SWNTs is around 2nm.The calculation also showed that the interstitial channel among SWNTs can become effective sites for hydrogen adsorption when the gap between two SWNTs increases.
Preparation and magnetic properties of nanocomposite Nd28Fe66B6 /Fe50Co50 bilayer films
Authors: Ao Qi  , Zhang Wa-Li  , Zhang Yi  , Wu Jian-Sheng  ,   上海交通大学，高温材料与高温测试教育部重点实验室，上海  200030
Published: December 2020

The nanocomposite Nd28Fe66B6/Fe50Co50 bilayer films with Mo underlayer and overlayer have been fabricated on Si substrates. All the samples prepared have perpendicular anisotropy and th e hysteresis loops are simple single loops for fixed Nd-Fe-B layer thickness (10 nm) and different FeCo layer thickness (dFeCo =1—100nm). The shape a nd the behavior of the initial loops and the minor loops suggest that wall pinni ng is the dominant coercivity mechanism in these films. The magnetization of the se samples is found to increase with increasing FeCo layer thickness for a fixed Nd-Fe-B layer thickness and the coercivity of films decrease with increasing Fe Co layer thickness. The sample of maximum energy product is 160×１０３A/m for dFeCo =5nm at room temperature. The enhancement of the rema nence and energy products in nanocomposite bilayer films is attributed to the ex change coupling between the magnetically soft and hard phases.
Effect of Ag and Ti underlayer on the ordering in Fe/Pt multilayers
Authors: Feng Chun  , Li Bao-He  , Teng Jiao  , Yang Tao  , Yu Guang-Hua  ,   (1)北京科技大学材料物理系,北京  100083; (2)北京科技大学材料物理系,北京  100083;北京工商大学数理部,北京  100037
Published: December 2020

The Fe/Pt multilayers with Ag,Ti,Cu,Cr,Pt and Ta underlayers were prepared by DC magnetron sputtering on the heated glass substrates.After vacuum annealing at d ifferent temperatures, the FePt thin films with L1０ ordering phase ( L1０-FePt) were obtained. Results showed that the Ag and Ti underlaye r prompt the ordering of FePt thin films, and the ordering temperature of FePt- L1０ phase is reduced by at least 150℃. It is also worth noting tha t the annealing time is shorter and the magnetic performance is excellent. The m agnetic performance of samples with Ag underlayer is not sensitive to temperatur e at relative higher annealing temperature, whereas the coercivity of samples wi th Ti underlayer decreases obviously when the annealing temperature is higher th an 500℃. After annealing at 400℃ for 20 min, the in-plane coercivity of sample s with Ag and Ti underlayer can be as high as 597kA/m, and 654kA/m， respectivel y, and the ratio of remanent magnetization to saturation magnetization reaches 0 .81 and 0.94, respectively, implying the potential of the films as future magnet ic recording media of ultrahigh density.
Composition-modulated hybrid tunnel junctions of La1－xSrxMnO3
Authors: Yu Dun-Bo  , Feng Jia-Feng  , Du Yong-Sheng  , Han Xiu-Feng  , Yan Hui  , Ying Qi-Ming  , Zhang Guo-Cheng  ,   (1)北京工业大学材料学院薄膜材料与技术研究室,北京  100022; (2)北京有色金属研究总院，有研稀土新材料股份有限公司,北京  100088; (3)北京有色金属研究总院，有研稀土新材料股份有限公司,北京  100088;中国科学院物理研究所磁学国家重点实验室,北京  100080;北京工业大学材料学院薄膜材料与技术研究室,北京  100022; (4)中国科学院物理研究所磁学国家重点实验室,北京  100080
Published: December 2020

Tunnel magnetoresistance junctions with the structure of SrTiO３-sub/ La0.7Sr0.3MnO３(100nm)/La0.96Sr 0.04MnO３ (5nm)/La0.7Sr0.3MnO３ (100nm)/Ir２２Mn７８(15nm)/Ni７９Fe２１(5nm)/Pt(20nm) were micro-fabricated with lithography and Ar ion etching. T he first three epitaxial layers of La0.7Sr0.3MnO３(100nm)/La0.96Sr0.04MnO３ (5nm)/La0.7Sr0.3MnO３ (100nm) were deposited on single crystal (0 01) SrTiO３-substrate by magnetron sputtering and heat treatment, the n the spinning and top conducting layers of Ir２２Mn７８(1 5nm)/Ni７９Fe２１(5nm)/Pt(20nm) were continuously fabricat ed on top the three epitaxial layers by normal magnetron sputtering. The coloss al TMR ratio of 3270% was observed at 4.2K under the external magnetic field of 8 T. The polarization value of 97% for the La0.7Sr0.3MnO３ is well consistent with the theoretical value of 100%. The present r esults directly indicate the half-metallic ferromagnetism in La0.7Sr0.3MnO３. The high TMR value can possibly be attributed to the good interface due to the perfect barrier.
Spectroscopic properties of Er3+-doped alkaline/alkaline-earth metal modified fluorophosphate glasses
Authors: Li Tao  , Zhang Qin-Yuan  , Feng Zhou-Ming  , Zhao Chun  , Jiang Zhong-Hong  ,   (1)华南理工大学特种功能材料及其制备新技术教育部重点实验室,华南理工大学材料学 院光通信材料研究所,广州  510640; (2)华南理工大学特种功能材料及其制备新技术教育部重点实验室,华南理工大学材料学 院光通信材料研究所,广州  510640;中科院上海光学精密机械研究所,上海  201800
Published: December 2020

This paper reports the spectroscopic properties of Er３＋-doped Al(PO ３)3-based fluorophosphate glasses for 1.5μm optical ampl ifiers. Effects of alkaline/alkaline-earth metal composition on the spectroscopi c properties of Er３＋ in fluorophosphate glasses are investigated. A strong correlation between the alkaline/alkaline-earth metal content and the s pectroscopic parameters, such as absorption and emission cross sections, Judd-Of elt intensity parameters and upconversion emission intensity, has been observed. The fluorophosphate glass with 12 mol% potassium fluoride exhibits the largest calculated stimulated-emission cross-section of 7.83×10-21cm２ and the smallest upconversion emission intensity among the fluorophosphate studied. The fluorophosphate glass with 23 mol% strontium fluoride has a broadb and near-infrared emission at 1.5μm with a full width at half-maximum over 65nm and a long upper level fluorescence lifetime of 8.6ms.
Efficient coupling from dielectric rib waveguide to two-dimensional photonic crystal waveguide
Authors: Bai Ning-Feng  , Liu Xu  , Xiao Jin-Biao  , Zhang Ming-De  , Sun Xiao-Han  ,   东南大学电子工程系,南京  210096
Published: December 2020

An efficient adiabatic coupling is presented in this paper for coupling light between rib dielectric waveguide and 2D photonic crystal waveguide (PCW). Using planar wave expand (PWE) method and FDTD method, the linear and nonlinear taper profiles are compared. Following with these, some widths of the entrance of the taper are compared and the best width is given. Simulation result have proved that transmission ratio above 95% can be obtained in a wider frequency range by usin g a cosine taper profile than line taper profile.
Numerical modeling of non-linear characteristics for barotropic atmosphere with external forcing
Authors: Wang Ping  , Dai Xin-Gang  ,   (1)中国科学院大气物理研究所，北京  100029; (2)中国科学院大气物理研究所，北京  100029；中国科学院研究生院，北京  100039
Published: December 2020

Some characteristics of barotropic atmosphere are illustrated by numerical modeling, basing on a potential vorticity equation with forcing, dissipation, and non -linear interaction. For the barotropic potential vorticity equation (named the barotropic model) on a β-plane channel its solution is a stationary, wave-like pattern under a certain thermal forcing, while a quasi-periodic oscillation betw een two essential flow patterns appears if north-south thermal heating and wave- like topography are added as the model forcing. The oscillation has a period abo ut 15d, very similar to atmospheric index cycle in middle and high latitudes. Th e low-index pattern corresponds to a blocking flow, whereas the high index one i s an intensive westerly flow. More oscillation solutions are expected when the e quation is under periodic boundary condition with a strong thermal forcing, and a similar quasi-periodic solution can be obtained, which also results from a wav e topography forcing. However, its low index pattern is symmetrical, and differe nt from the blocking pattern produced by the β-plane model. When the heating fo rcing becomes weak, there also exists a stationary solution. Therefore, the char acteristics of atmospheric index cycle may not be soundly manifested by an analy tical solution or numerical solution under periodic boundary condition using low -order spectrum method that approximates the barotropic model in the β-plane ch annel.
Conserved quantity and stability of Birkhoffian system
Authors: Xu Zhi-Xin  ,   江苏科技大学船舶与海洋工程学院，镇江  212003
Published: December 2020

It is showed that Stability of Birkhoffian system can be determined by its conserved quantities. If a conserved quantity or a combination of some conserved quantities became a Liapunov function,then it can be used to study the stability of equilibrium and the stability of motion of the system.
Lie-form invariance of holonomic mechanical systems
Authors: Ge Wei-Kuan  , Zhang Yi  ,   (1)湖州师范学院物理系，湖州  313000; (2)苏州科技学院土木工程系，苏州  215011
Published: December 2020

This paper presents the definition and criterion for holonomic mechanical systems. The Noether conserved quantity, the Hojman conserved quantity and the Lutzky conserved quantity deduced by the Lie-form invariance are obtained. An example is given to illustrate the application of the result.
Planar vibration of a thin elastic rod with circular cross section in viscous medium
Authors: Liu Yan-Zhu  ,   上海交通大学工程力学系，上海  200030
Published: December 2020

The planar vibration of a thin elastic rod with circular cross section in viscous medium is discussed. Based on the Kirchhoff's theory the dynamical equations of the rod are established in the Frenet coordinates of the centerline. The torsional vibration is decoupled from the flexural vibration when the centerline is an arbitrary planar curve. The planar torsional vibration of an arbitrary planar rod and the planar flexural vibrations of an axially compressed straight rod and a ring without torsion are discussed when the ends of the rod are fixed. The natural frequencies and the damping coefficients are derived. It is proved that the Lyapunovs and Eulers conditions of stability of an axially compressed straight rod in the space domain are the sufficient and necessary condition of asymptotic stability of the rod in the time domain, or the necessary condition of stability of the rod without damping. The asymptotic stability of a ring in viscous medium is always satisfied.
Stochastic resonance for bias-signal-modulated noise in a linear system
Authors: Xu Wei  , Jin Yan-Fei  , Xu Meng  , Li Wei  ,   (1)西北工业大学应用数学系，西安  710072; (2)西北工业大学应用数学系，西安  710072;南京航天航空大学振动工程研究所，南京  210016; (3)西北工业大学自动控制系，西安  710072
Published: December 2020

The stochastic resonance (SR) is studied in an overdamped linear system when the bias-signal-modulated noise is introduced. The exact expressions of the first two moments and signal-to-noise ratio(SNR) are obtained when we introduce the asymmetric dichotomous noise into the system. We find that the system has three different forms of SR: the conventional SR, the bona fide SR and SR in the broad sense. Moreover, the additive noise weakens the SNR of the linear system while the cross-correlation enhances the SNR and improves the output signal.
Sufficient conditions of chaotic synchronization and its applications
Authors: Chen Bin  , Liu Guang-Hu  , Zhang Yong  , Zhou Zheng-Ou  ,   电子科技大学电子工程学院,成都  610054
Published: December 2020

At present time, only necessary conditions of chaotic synchronization are known, and applications of chaotic synchronization is limited. In this paper, sufficient conditions of continuous chaotic system synchronization and the proofs are presented, and evolutive range of state variables is presented, too. We proved the conditions are realizable. As an application of the theory, we proved sufficient conditions of time-varying parameter chaotic synchronization, and made simulations by Chua circuits. Time varying parameter chaotic synchronization communication has high security performance, and the simulations that it defeat all kinds of attacks of eavesdroppers are presented.
Application of homotopy technique with the parameter expansion to strongly nonlinear stochastic dynamic systems
Authors: Xu Wei  , Sun Zhong-Kui  , Yang Xiao-Li  ,   (1)西北工业大学应用数学系,西安  710072; (2)西北工业大学应用数学系,西安  710072;陕西师范大学数学系,西安  710062
Published: December 2020

This paper extends the method of PE-HAM to strongly nonlinear stochastic dynamic system under harmonic and Gauss white noise excitations. By constructing an appropriate homotopy mapping, the original system is transformed into a set of linear stochastic differential equations. In addition, the strongly nonlinear Duffing oscillator subjected to harmonic and Gauss white noise excitations is investigated using the proposed method, and its approximate analytically solution process and steady-state probability density are obtained. Numerical simulation is employed to verify the theoretical result and good agreement is found.
Study on the orientation parameter of excited sodium scattered by electrons
Authors: Liu Yi-Bao  , Pang Wen-Ning  , Ding Hai-Bing  , Shang Ren-Cheng  ,   (1)清华大学物理系，北京  100084; (2)清华大学物理系，北京  100084;东华理工学院物理系，抚州  344000
Published: December 2020

The orientation parameter is used to describe the collision dynamic process and the structure informations of excited atomic state in electron scattering. In density matrix theory, the state multipoles express the structure of atom assembles impacted by particles, and the state multipole of K=1 expresses the orientation vector. In the sysmetry scattering plane system, the orientation vector is denoted by the orientation parameter L⊥, which is calculated from scattering amplititutes, C-G coefficient and 6-j symbol. The orientation parameters of sodium S→P excited by low energy electron are calculated in this paper, and the results are consistent with that obtained from electron-photon coincidence scattering experiment from 2eV—100eV incident energy. The characteristics of orientation angular-distribution vs incident energy are also discussed.