bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study on the terminating mechanisms of copper vapor laser pulse
Authors: Jin Yi  , Pan Bai-Liang  , Chen Gang  , Chen Kun  , Yao Zhi-Xin  ,   浙江大学物理系，杭州 310027
Published: December 2020

A self-consistent physical model describing the kinetic process of the longitudinal pulsed discharge-excited copper vapor laser was established, and numerical solutions of the model were obtained. The terminating mechanisms of the copper vapor laser pulse have been further analyzed according to the simulation results. It is shown that the important factors resulting in the termination of laser pulse are the processes of stimulated emission transition, the electron impact excitation of the lower laser level and the depopulation of the upper laser level to the higher excitation levels by electron collisions.
Experimental study on thermal lensing of end-pumped solid-state lasers
Authors: Guan Jun  , Li Jin-Ping  , Cheng Guang-Hua  , Chen Guo-Fu  , Hou Xun  ,   中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安 710068
Published: December 2020

A laser interferometry method of measuring the thermal lensing of end-pumped solid-state lasers is proposed. This method provides a way easy to be carried out is real-time, having no influence on laser system, with a high spatial resolution for diagnosing thermal lensing. By this method, thermal lensing of end-pumped Nd:YVO4 laser is studied in detail. And this work provide a means for studying the thermal effects of laser medium and designing lasers of this kind.
Passive Q-switched mode locking of double-clading Yb:fiber laser with ion-implanted GaAs
Authors: Wang Yong-Gang  , Ma Xiao-Yu  , Fu Sheng-Gui  , Fan Wan-De  , Li Qiang  , Yuan Shu-Zhong  , Dong Xiao-Yi  , Song Yan-Rong  , Zhang Zhi-Gang
Published: December 2020

We report the technique of the ion-implanted semi-insulating GaAs wafer used for passive Q-switched mode locking in double-cladding Yb:fiber laser. The wafer was implanted with 400-keV energy, 1016/cm2 dose As+ions, and was annealed at 600℃ for 20 min. At the pump power of 5W, we achieved output power of 200mW. The repetition rate of envelope of Q-switched mode locking is 50-kHz with a FWHM envelope of 4μs. The repetition rate of mode locked pulse train was found to be 15-MHz. This is the first report of such a kind of laser to the best of our knowledge.
Phase transition speed research of metal material at laser irradiation medium strength
Authors: Zhang Ke-Yan  ,   涪陵师范学院物理系,重庆 涪陵 408005
Published: December 2020

Under the condition that there is only solid-liguid transition in a metallic material, we found the laser power density for melting the material. Through analysis of the similarity of some behaviors of solid and ciquid states, we obtain the absorptivity of laser by the metal, and indicate the impossibility to directly calculate the transition rate of the metal. However, we can obtain the transition rate under the irradiation of laser, and find the relationship of the transition rate with the intensity and the frequency of the laser.
The study on the microstructure of TiN and Ti1-xSixNy coatings
Authors: Zhang Chen-Hui  , Luo Jian-Bin  , Li Wen-Zhi  , Chen Da-Rong  ,   清华大学摩擦学国家重点实验室,北京 100084
Published: December 2020

The microstructure of TiN coatings and Ti1-xSixNy nanocomposite coatings was studied by means of x-ray diffrection, x-ray photoelection spectroscopy, high resolution transmission electron microscopy and atomic force microscopy. The results showed that the Ti1-xSixNy coatings consisted of TiN nanocrystallites with grain size of 3-5nm and amorphous Si3N4 phase. The roughness of Ti1-xSixNy coatings was less than that of TiN coatings prepared under the same conditions. The orientation of TiN crystals in the Ti1-xSixNy coatings was discussed on the basis of interface energy.
Analysis on Z-scan characteristics of cascade structure
Authors: Zang Wei-Ping  , Tian Jian-Guo  , Liu Zhi-Bo  , Zhou Wen-Yuan  , Mei Can  , Song Feng  , Zhang Chun-Ping  ,   南开大学物理科学学院光子学中心，天津 300071
Published: December 2020

In this paper, Z-scan characteristics of the cascade structure of nonlinear media are analyzed, analytic and numerical solutions are obtained. Analytic analysis is based on the combination of Gaussian decomposition method (GDM) with the distributed lens method, and numerical calculation is based on the Crank-Nicholson finite difference scheme and fast Hankel transformation. Meanwhile, the conditions and method to apply these two numerical analyses are also given. Comparing analytic solutions with numerical calculation and experimental results, it is shown that they agree very well with each other.
Low intensity spatial solitons in centrosymmetric photorefractive materials
Authors: Hou Chun-Feng  , Meng Qing-Xin  , Gong De-Wei  , Zhang Jian-Long  ,   哈尔滨工业大学物理系,哈尔滨 150001
Published: December 2020

The exact bright, dark and grey spatial soliton solutions for the optical wave evolution equation in centrosymmetric photorefractive materials are obtained analytically, and the explicit expressions for the width of these spatial solitons are also presented.
Guide modes at interface of photonic crystal heterostructures composed of different lattices
Authors: Liu Jiang-Tao  , Zhou Yun-Song  , Wang Fu-He  , Gu Ben-Yuan  ,   首都师范大学物理系,北京 100037
Published: December 2020

We have investigated the guide modes in two kinds of two-dimensional photonic crystal heterostructures by using the plane wave expansion method combined with the supercell technique. These heterostructures consist of different air cylinders embedded into host dielectric in different lattices. Namely, One heterostucture is composed of square cylinders in square lattice and hexagon cylinders in triangular lattice (SSTH heterostucture). The other heterostucture is composed of rectangular cylinders in rectangular lattice and circle cylinders in triangular lattice(RRTC heterostucture). We find that the SSTH heterostucture may produce guide modes in absolute photonic band gap (PBG) when introducing relative longitudinal gliding or transverse displacement of the sub-lattices along the interface of the heterostructure. But the RRTC heterostucture can produce guide modes in absolute PBG without any relative longitudinal gliding or transverse displacement. This feature is quite different from other pure dielectric photonic crystals heterostructures.
Electro-optical properties of holographic polymer dispersed liquid crystal devices
Authors: Zhang Bin  , Liu Yan-Jun  , Xu Ke-Shu  ,   北京交通大学理学院物理系,北京 100044
Published: December 2020

Holographic polymer dispersed liquid crystals（HPDLC）are a kind of novel photoelectronic information functional materials. It has the perfect characters including high diffraction efficiency, rapid response and easy manufacture. HPDLC devices are potentially useful for optical communication, panel display, information storage and integrated optics. Based on the study of the diffraction properties optimization of HPDLC，we have established the measurement system for electro-optical properties of the HPDLC device. The influence of different surfactants loading on the anchoring energy of liquid crystal have been explored, which was demonstrated to be a good way to decrease the operating voltage. The experimental results indicated that the index matching plays an important role in improving the contrast ratio of device. The response time was measured and the average response time of 100μs was obtained.
Study on mode degeneracy in photonic crystal fibers
Authors: Ren Guo-Bin  , Wang Zhi  , Lou Shu-Qin  , Jian Shui-Sheng
Published: December 2020

A novel full vector model is applied to analyze the photonic crystal fibers (PCF). From symmetry analysis of modes of a waveguide, we classify the modes of PCF into nondegenerate or degenerate pairs according to the minimum waveguide sectors and its appropriate boundary conditions. We present the modes of PCF that can be labeled by its step index fiber analogs. It is shown that these modes either exhibit the full waveguide symmetry and nondegenerate or occur in degenerate pairs that support this symmetry only in combination. The doublet of the degenerate pairs in which both have the same symmetry as PCF will be split into two nondegenerate modes.
Dispersion properties of high-index-core Bragg fibers
Authors: Ren Guo-Bin  , Wang Zhi  , Lou Shu-Qin  , Jian Shui-Sheng
Published: December 2020

The dispersion properties of high-index core Bragg fibers are investigated by superlattice model. We have analyzed the scaling properties of waveguide dispersion, discussed the dependence of waveguide dispersion on fiber structure parameters: the core radius, radial periodicity and filling ratio of the cladding, and designed an example structure of Bragg fiber for broadband flattened dispersion at 1.55μm.
Study on 1.55μ m AlGaInAs-InP polarization-insensitive semiconductor optical amplifier and its temperature characterizatics
Authors: Ma Hong  , Chen Si-Hai  , Jin Jin-Yan  , Yi Xin-Jian  , Zhu Guang-Xi  ,   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

Polarization-insensitive AlGaInAs-InP semiconductor optical amplifier is realized at wavelength of 1.55 μm. The active layer consists of three tensile-strained wells with a strain of 0.35%. The amplifier is fabricated with a ridge waveguide structure. The testing result shows that the amplifiers have an excellent polarization insensitivity (less than 0.5 dB) over the entire range of wavelength (from 1530 to 1580nm). The 1540 nm wavelength optical gain is 20 dB at the bias current of 200 mA. The AlGaInAs-InP optical amplifier shows good temperature characteristics, less than a 3dB reduction in the gain and polarization-insen sitivity when the temperature is raised from 25℃ to 65℃.
Vector analysis of dispersion for the fundamental cladding mode in photonic crystal fibers
Authors: Li Shu-Guang  , Liu Xiao-Dong  , Hou Lan-Tian  ,   燕山大学红外光纤与传感研究所，秦皇岛 066004
Published: December 2020

The dispersions of the fundamental cladding mode in photonic crystal fibers(PCFs)are computed with a vectorial effective index approach in this paper. By comparing with the results obtained from biorthonormal-basis method or scalar effective method,it is found that the results of this paper are in accordance with that obtained from the biorthonormalbasis method, and that the scalar effective method is a good approximation at a lower air-filling fraction or higher normalized wave-number A/λ. For high accuracy at larger air-filling fraction or lower normalized wave-number A/λ,it is necessary to consider the vectorial method. The relation between effective index of cladding and microstructure of PCFs is discussed. The computation and analysis in this paper can provide a theoretic reference for designing of PCFs.
Numerical study on dispersion compensating property in photonic crystal fibers
Authors: Li Shu-Guang  , Liu Xiao-Dong  , Hou Lan-Tian  ,   燕山大学红外光纤与传感研究所，秦皇岛 066004
Published: December 2020

The dispersion compensating property in photonic crystal fibers (PCFs) is simulated with a vectorial effective=index approach in this paper. It is found that the dispersion, dispersion slope, and Kappa parameter of PCFs can be designed neatly by changing the air hole size and the pitch in PCFs cladding. We can obtain PCFs with large absolute value of normal dispersion and negative dispersion slope at the wavelength of 1.55μm.Conventional communication nonshifted single-mode fibers (G652) and nonzero-dispersion shifted fibers (NZ-DSF,G655) can be compensated efficiently at wavelengths around 1.55μm low-loss optical communication window. It is demonstrated that there are huge potentials in designing dispersion compensating PCFs.
Numerical analysis of metal melting and evaporating with liquid surface depression
Authors: Bo Yong  , Wang De-Wu  , Ying Chun-Tong  ,   清华大学 工程物理系，北京 １０００８４
Published: December 2020

A metal molten-pool is described by the Navier-Stokes and energy equations and the depressed liquid surface is described by the Young-Laplace equations,and the metal evaporation is described by the BGK equation. The velocity and temperature distributions of the pool and the vapor heated by an electron gun are solved by the finite difference method. The numerical results show the evaporation rate of the metal increases with the power of the electron gun, so the vapor density increases and the vapor temperature decreases and the vapor velocity increases. The surface temperature of the pool with the depressed surface is less than the one of the pool with the plane surface, so is the metal evaporation rate. The difference of the evaporation rate between them increases with the power of the electron gun, so the liquid surface depression should be taken into consideration for a high power electron gun.
Modulatory character of microwave reflection behavior in electrorheological fluids
Authors: Huang Min  , Zhao Xiao-Peng  , Wang Bao-Xiang  , Yin Jian-Bo  , Cao Chang-Nian  ,   西北工业大学电流变技术研究所，西安 710072
Published: December 2020

The microwave reflection behavior of electrorheological (ER) fluids containing TiO2 coated Kaolinite and Y doped BaTiO3 was investigated in the case that the direction of the TE10 module to the electrical field is vertical. We found that the reflection coefficient of TiO2 coated Kaolinite and Ydoped Ba TiO3 based ER fluids increased with the electrical field. However, the increase of reflection coefficient of Ydoped BaTiO3 based ER fluid was more significant compared with that of TiO2 coated Kaolinite. At the same time, the reflection coefficient of Y doped BaTiO3 ER fluid showed strong dependence on particle volume fraction. There was a critical volume fraction. When the volume fraction was lower than this critical value, the reflection coefficient gradually increased, otherwise the reflection coefficient initially increased and then decreased with electrical field. It was also found that the reflection wave phase of TiO2 coated Kaolinite ER fluid initially increased and reached its maximum value, then declined to a constant. The reflection wave phase of Y doped BaTiO3 ER fluid, however, steadily increased with the electrical field. We considered that the modulatory character of microwave reflection behaviors was attributed to the change in structure, electric properties of ER fluids and dispersed phase under electric field.
Asymptotic estimation for the system of electro-rheological fluids
Authors: Ouyang Cheng  ,   湖州师范学院理学院，湖州 313000
Published: December 2020

By the movement model of ball particles in electrorheological(ER) fluids, the asymptotic behavior of the movement of the particles in ER fluids is considered when the mass of the particles is small. Using the theory of differential inequalities, the expression of asymptotic estimation is given and proved.
Structure transition and magnetic properties of ((Nd1－xErx)2Co15.5V1.5 compounds
Authors: Liu Bao-Yu  , Liu Guo-Dong  , Wu Guang-Heng  , Yang Fu-Ming  ,   辽宁石油化工大学机械分院，抚顺 113001
Published: December 2020

Structure and magnetic properties of (Nd1-xErx)2Co15.5V1.5compounds have been investigated by means of x-ray diffraction and magnetic measurements. The results obtained show that the (Nd1-xErx)2Co15.5V1.5 compounds crystallize in the Th2Zn17type structure for lower Er content(x0.5). The two structures coexist in the samples with x=0.4 and 0.5 The lattice constants a and c, and the unit cell volumeV show a decreasing tendency with increasing Er content in both structures. With increasing Er content, at room temperature, the anisotropy of the (Nd1-xErx)2Co15.5V1.5 compounds changes from the easycone type for low Er content(x0.5). The spin reorientation transition is observed for the compounds with x=0.0—0.5, and the spin reorientation temperature Tsr shows a decreasing tendency with increasing Er content. In addition, the Curie temperature TC and saturation magnetization Ms also decrease monotonically with the Er substitution for Nd in (Nd1-xErx)2Co15.5V1.5 compounds.
Liquid phase flow and microstructure formation during rapid solidification
Authors: Xu Jin-Feng  , Wei Bing-Bo  ,   西北工业大学应用物理系，西安 710072
Published: December 2020

The characteristics of rapid solidification and microstructure formation of Fe-50wt%Sn hypermonotectic alloy heve been investigated. The rapid solidification microstructure is composed of regular arrays of fiberlike βSn phase, αFe phase distributed in fiber interspacings, and a small amount of metallic compounds. The angle between the fiber array and ribbon surface is within the range of 0—15°. According to the heat transfer equation and NavierStokes equation under melt-spinning condition, the solidification behaviors and microstructure formation processes are analyzed theoretically. It is revealed that the liquid phase flow has a remarkable effect on the phase separation of hypermonotectic alloy. This separation behavior occurs in the bottom of the melt puddle, which is about 200μm from roller surface, where the shapes of separated L2 droplets are deformed by shear stress. The collision/stretch of the separated L2 droplets finally leads to the formation of fiberlike microstructures. Due to the high cooling rate, the peritectic transformation at elevated temperatures is suppressed, thus resulting in the existence of some metastable phase at room temperature.
The rheological behavior of bulk metallic glass Zr41Ti14Cu12.5Ni10Be22.5
Authors: Wang Jing-Feng  , Liu Lin  , Pu Jian  , Xiao Jian-Zhong  ,   华中科技大学材料科学与工程学院模具技术国家重点实验室，武汉 430074
Published: December 2020

The temperature dependence of viscosity of the bulk metallic glass Zr41Ti14Cu12.5Ni10Be22.5（Vit1）under constant heating condition was obtained by application of static extension measurement. A few strain rate peaks, which are associated with the glass transition and multistep crystallization, were observed in the temperature-strain rate curve. Above the glass transition temperature, the supercooled liquid of the bulk metallic glass showed the Newtonian rheological characteristic, and its temperature dependences of viscosity in supercooled liquid region can be fitted well with the Vogel-Fulcher-Tammann(VFT) equation. The sample exhibited the fragility parameter D* value of 36, the VFT temperature T0 of 319K and the fragility m value of 30 It was shown that the Vit1 alloy is a strong liquid, similar to sodium silicate liquids. However, the relation between temperature and viscosity deviated from VFT equation below the glass transition temperature.The phenomenon is tentatively interpreted in terms of free-volume model and structure relaxation concept.
Spectra analysis of Ce:YAlOZr3 single crystals grown by temperature gradient technique
Authors: Zeng Xiong-Hui  , Zhao Guang-Jun  , Xu Jun  ,   中国科学院上海光学精密机械研究所，上海 201800
Published: December 2020

YAlO3 single crystal doped with Ce3+ at concentration 1at% was grown by the temperature gradient technique (TGT). The as rown crystal was pink. After H2 annealing or O2 annealing at 1400℃, the crystal turned into colorless. At the same time, the absorption spectra showed obvious changes. A colorcenters model could successfully explain the experimental phenomena. There are selfabsorption and selfexcitation around 330 nm according to the absorption spectrum and luminescence spectra excited by ultraviolet ray. The emission peak of luminescence spectra under ultraviolet ray excitation is around 368 nm and the emission peak of luminescence spectra under x-ray excitation is around 391nm. These results suggest that the self-absorption can be decreased under x-ray excitation. In addition, the emission intensity of the crystals annealed in H2 or air is higher than that of the as-grown crystal sample.
Test methods of total dose effects in verylarge scale integrated circuits
Authors: He Chao-Hui  , Geng Bin  , He Bao-Ping  , Yao Yu-Juan  , Li Yong-Hong  , Peng Hong-Lun  , Lin Dong-Sheng  , Zhou Hui  , Chen Yu-Sheng  ,   西北核技术研究所，西安69信箱13分箱，西安 710024
Published: December 2020

A kind of test method of total dose effects (TDE) is presented for very large scale integrated circuits (VLSI). The consumption current of devices is measured while function parameters of devices (or circuits) are measured. Then the relation between data errors and consumption current can be analyzed and mechanism of TDE in VLSI can be proposed. Experimental results of 60Co γ TDEs are given for SRAMs, EEPROMs, FLASH ROMs and a kind of CPU.
Dynamics of dislocation and global bifurcation for a system
Authors: Luo Shi-Yu  , Shao Ming-Zhu  , Wei Luo-Xia  , Liu Zeng-Rong  ,   东莞理工学院，东莞 523106
Published: December 2020

An external periodic field has been introduced in the Seeger equation; a motion equation of a crystal dislocation has been induced to Duffing function with the hard—spring properties.A global bifurcation of the system and a probable way into the chaos have been discussed by using Melnikov methoud. It shows that the system enters into the critical state , then enters the chaos by the cascading bifurcation, if δ/α is defined and Ω is reduced continuously.
Surface phonons on Ag (110): A study by means of analytic embedded-atom method
Authors: Yang Jian-Yu  , Deng Hui-Qiu  , Hu Wang-Yu  ,   湖南大学应用物理系，长沙 410082
Published: December 2020

The surface phonons on Ag(110)are studied in the present paper by means of the lattice dynamics and an analytic embeddedatom method(EAM). The phonon frequencies and disperse curves with surface relaxation are in good agreement with the data obtained by the helium atom scattering experiments. The polarization and localization of surface vibration are in accord with the two-dimensional symmetry in the surface. The S2 and S3 surface modes along-direction are predicted, which are in agreement with the helium atom scattering experiments.
The fabrication of high-quality periodic porous alumina templates
Authors: Ma Chun-Lan  ,   苏州科技学院应用物理系；苏州 215009
Published: December 2020

Porous alumina films can be achieved by anodizing an ultra pure aluminum sheet in proper conditions. Both the distribution and the size of the pores are regular. The depths of the pores are uniquely limited by the anodization time thus very deep pores can be obtained, in the order of mm. Such a porous structure can be employed to serve as the templates for nanosized materials. The Oxalic acid of 0.3mol/L was used in our experiments with the applied DC voltage 40 V. The two-step method was involved to fabricate the templates. The resultant templates exhibit regular porous section. The pore size is ～40—70 nm and the pore-pore spacing is～110 nm. The depth is～0.4 mm. The dependence of the template quality on the solution (oxalic acid) temperature was analyzed and the comparison between the single-step and two-step anodization was made. The results indicate that low solution temperature and two-step method are necessary.
Growth structure and mechanical properties of TiN/SiC nano-multilayers
Authors: Lao Ji-Jun  , Kong Ming  , Zhang Hui-Juan  , Li Ge-Yang  ,   上海交通大学金属基复合材料国家重点实验室；上海 200030
Published: December 2020

The formation of cubic SiC（B1cubic SiC） and its effect on the mechanical properties of TiN/SiC nanomultilayers were studied in this work. The results show that in TiN/SiC mulytilayer, SiC exists as a cubic structure and forms coherent epitaxially grown columnar crystal superlattice with TiN when the thickness of SiC layer is about 06nm. Multilayers show the superhardness effect with the enhancement of hardness and elastic modulus, and the highest hardness excess 60GPa. With the increase of SiC layer thickness, B1SiC transforms into amorphous phase and impedes the coherent epitaxial growth of multilayers. Multilayers present layer structure character composed of TiN nanocrystal and amorphous SiC. Correspondingly, the hardness and elastic modulus of multilayers decrease. The formation of cubic SiC and coherent growth structure of cubic SiC and TiN appear to be likely the origin of the superhardness effect of TiN/SiC nano-multilayers.
Study of CaTiO3 structure under high pressure
Authors: Wu Xiang  , Qin Shan  , Wu Zi-Yu  , DongYu-Hui  , Liu Jing  , Li Xiao-Dong  ,   中国科学院高能物理研究所同步辐射室；北京 100039
Published: December 2020

In situ high-pressure (up to 44-53 GPa) energy dispersive x-ray diffraction experiments have been carried out on CaTiO CaTiO 3, structure, high pressure, equation of state in a diamond anvil cell at room temperature by using synchrotron radiation. Experimental data show that the a and b axes have similar compressibilities with large variation, while the c axis is less compressible with increasing pressure. However, there is no evidence of any structural transformation in this pressure range. The isothermal P-V equation of the state of CaTiO CaTiO 3, structure, high pressure, equation of state is fitted using the Murnaghan equation of state, which yields values of V0=0.2245(6)nm 3 and K 0=222(9) GPa assuming the pressure derivative K′0=4 According to the relation of the pseudo-cubic angle γpc and pressure, the structure of CaTiO CaTiO 3, structure, high pressure, equation of state will reduce its symmetry under hydrostatic pressure.
The study of anti-Stokes photoluminescence properties in the YZr2OZr3:Er3+　nanocrystals
Authors: Wang Xin  , Shan Gui-Ye  , An Li-Min  , Chao Ke-Fu  , Zeng Qing-Hui  , Chen Bao-Jiu  , Kong Xiang-Gui  ,   中国科学院长春光学精密机械与物理研究所激发态物理重点实验室,长春 130033
Published: December 2020

The homogeneous precipitation method was used for preparing nanocrystalline erbium-doped Y2O3 with various molar concentrations. These materials synthesized in the system were characterized with XRD, SEM micrograph and PL spectra. Stokes and antiStokes PL emissions of Y2O3:Er3+ nanocrystals were investigated, whose intensities were varied evidently with a range of dopant erbium ions concentration. When the molarity of dopant erbium ions is close to 2.0%, the relative intensities of anti-Stokes PL spectra are dominant. From the XRD and SEM micrograph, the Y2O3:Er3+ nanocrystal with cubic structure is verified and the distribution of particles size is homogeneous. The experimental results indicate that the anti-Stokes emission results from twophoton absorption process in the Y2O3:Er3+ nanocrystal system.
Spin-orbit and exchange interaction in a HgMnTe magnetic two-dimensional electron gas
Authors: Qiu Zhi-Jun  , Gui Yong-Sheng  , Shu Xiao-Zhou  , Dai Ning  , Guo Shao-Ling  , Chu Jun-Hao  ,   中国科学院上海技术物理研究所红外物理国家重点实验室；上海 200083
Published: December 2020

Spin-orbit interaction and spd exchange interaction are investigated by analyzing beating patterns of Shubnikov-de Hass oscillations in a HgMnTe magnetic two-dimensional electron gas (2DEG) at various temperatures.The results show that (1) spin-orbit interaction results in zero-magnetic-field spin splitting in 2DEG; (2) spin-orbit interaction is dominant at low magnetic field, and the total spin-splitting decreases with increasing magnetic field due to the influence of Landau splitting and Zeeman splitting; (3) at a high magnetic field, the spd exchange interaction tends to saturate and the spin splitting corresponds to Zeeman splitting. The experiments demonstrate that the spin splitting deduced from fast Fourier transformation (FFT) of SdH oscillations versus. 1/B is different from zero-magnetic-field spin splitting when Zeeman spin splitting is comparable to zero-magnetic-field spin splitting.
Microscopic origins of the spin-Hamiltonian parameters for 3d2 state ions in a crystal
Authors: Yang Zi-Yuan  ,   西安电子科技大学微电子所；西安 710071;宝鸡文理学院物理系，化学物理研究所；宝鸡 721007
Published: December 2020

By adopting the intermediate-field scheme, the microscopic origins of the spin-Hamiltanian (SH) parameters for 3d2ion at trigonal (C3v, D3, D3d) symmetry, taking into account the spinspin(SS) and spin-other-orbit(SOO) coupling interactions omitted in previous publications, have been investigated on the basis of complete diagonalization method(CDM). We find that the SH parameters arise from four microscopic mechanisms, i.e. (1) Spin-orbit(SO) coupling mechanism; (2) SS coupling mechanism; (3) SOO coupling mechanism; (4) SO-SS-SOO combined coupling mechanism. The SO coupling mechanism in the four coupling mechanisms is the most important one, but the contributions to zero-field splitting parameter D from other three coupling mechanisms cannot be omitted.
Investigation of the model of the discharge properties of the unbalanced magnetron sputtering system
Authors: Mu Zong-Xin  , Li Guo-Qing  , Che De-Liang  , Huang Kai-Yu  , Liu Cui  ,   大连理工大学三束材料改性国家重点实验室,大连 116024
Published: December 2020

The voltage current property of the unbalanced magnetron sputtering (UMS) system has significant influence on the sputtering process and films deposition process. Based on the analysis of the relationship between unbalanced magnetic field and properties of the unbalanced magnetron sputtering system, according to Child law the model of the V-I property of the UMS system is set up. Comparisons between the model calculation results and the experimental data indicate that the model correctly expresses the relation between the unbalanced magnetic field and the discharge properties of the UMS system.
Diffusion of implanted Mo in Zr57Nb5Cu15.4Ni12.6Al10 non-crystalline alloy
Authors: Wang Xiu-Ying  , Gao Ming  , Sun Li-Ling  , Liu Ri-Ping  , Zhang Jun  , Wang Wen-Kui  ,   (1)河北省亚稳材料制备技术与科学重点实验室，燕山大学材料工程学院，秦皇岛 066004; (2)河北省亚稳材料制备技术与科学重点实验室，燕山大学材料工程学院，秦皇岛 066004;中国科学院物理研究所，北京 100080; (3)燕山大学产业集团，秦皇岛 066004; (4)中国科学院物理研究所，北京 100080
Published: December 2020

Diffusion of implanted Mo in the Zr57Nb5Cu15.4Ni12.6Al10 bulk non-crystalline alloy has been researched using secondary ion mass spectroscopy (SIMS). Activation energy Q and pre-exponential factor D0 were obtained to be 1.95 eV and 1.13×10-5m2s-1, respectively. Based on the Stokes-Einstern relation, the viscosity of the Zr57Nb5Cu15.4Ni12.6Al10 bulk non-crystalline alloy was investigated at temperatures below the glass transition, it decreases with the increase of temperature from 1.07×1010 Poise at 593 K to 1.42×108 Poise at 673 K.
Left-right coupling of circularly polarized light propagating inside biaxially　gyrotropic left-handed media
Authors: Shen Jian-Qi  , Zhuang Fei  ,   浙江大学现代光学仪器国家重点实验室，光及电磁波研究中心；杭州 310027;浙江大学物理系，浙江近代物理中心；杭州 310027
Published: December 2020

The left-right coupling of circularly polarized light in biaxially gyrotropic left-handed media is considered in the present paper. It is shown that this left-right coupling gives rise to the frequency shifts of both left and right handed polarized light propagating inside the biaxially gyrotropic left-handed media. In addition, we discuss the physical origin of left-right couplings of polarized light (i.e.,the nonlocal polarization effect), and its potential applications (e.g., controllable position-dependent frequency shifts) in information science.
Study on optical properties of diamond films by means of infrared spectroscopic ellipsometry
Authors: Shen Hu-Jiang  , Wang Lin-Jun  , Fang Zhi-Jun  , Zhang Ming-Long  , Yang Ying  , Wang Lin  , Xia Yi-Ben  ,   上海大学材料科学与工程学院；上海 201800
Published: December 2020

We have made spectroscopic ellipsometric measurement to characterize the structure of diamond films in infrared region (2.5—12.5μm). These films are grown respectively by microwave plasma chemical vapor deposition (MPCVD) and hot filament chemical vapor deposition (HFCVD). It is found that the establishment of appropriate models has the strongest influence on the fit of ellipsometric spectra. The best fit is achieved for MPCVD film with a 77.5nm middle layer of SiO2, and for HFCVD film with a 879nm rough surface layer included by Bruggeman effective medium approximation. Finally, the refractive index (n) and the extinctive coefficient (k) are calculated for both films, which show that the film grown by MPCVD is optically better than by HFCVD apparently.
The electron trap effect of the sulfur + gold sensitization center on the photoelectron behaviors
Authors: Li Xiao-Wei  , Li Xin-Zheng  , Jiang Xiao-Li  , Yu Wei  , Tian Xiao-Dong  , Yang Shao-Peng  , Fu Guang-Sheng  ,   河北大学物理科学与技术学院；保定 071002
Published: December 2020

The temporal behavior of free photoelectrons and shallow-trapped electrons in the T grains AgBrI emulsion was detected with the microwave absorption and dielectric spectrum detection technique. The results indicate that the effect of sensitization center on the photoelectron decay differs in different time ranges of the first-order decay curves, and that the electron trap effects of sulfur+gold sensitization center change from shallow trap to deep trap with increasing sensitization density. The optimal sensitization density of sulfur+gold was obtained on the basis of the relationship between the sensitization density and the decay time.
Stationary solution of motion of active Brownian particle
Authors: Deng Mao-Lin  , Hong Ming-Chao  , Zhu Wei-Qiu  , Wang Yuan-Mei  ,   (1)浙江大学非线性随机力学实验室，杭州 310027; (2)浙江大学计算中心，杭州 310027; (3)浙江大学生物医学工程系，杭州 310027
Published: December 2020

The stochastic averaging method for a quasi-integrable Hamiltonian system has been applied to the study of the motion of active Brownian particles. Firstly, the stochastic averaging method is introduced. Then, the stationary solution of the dynamic equations governing an active Brownian particle moving in a plane with Schienbein-Gruler velocity-dependent friction model subject to Guassian white noise excitation is obtained by using this method. The solution is proved validated by comparison with the results from digital simulation and those from experiment. Finally, the solutions for the Rayleigh and Erdamnn model are also given.
Non Noether conserved quantity of the holonomic mechanical systems in terms of quasi-coordinates ——An extension of Hojman theorem
Authors: Qiao Yong-Fen  , Zhao Shu-Hong  , Li Ren-Jie  ,   (1)东北农业大学工程学院，哈尔滨 150030; (2)莱阳农学院基础部，莱阳 265204; (3)浙江工程学院机械工程与自动化系，杭州 310033;莱阳农学院基础部，莱阳 265204;东北农业大学工程学院，哈尔滨 150030
Published: December 2020

Using the Lie symmetry under infinitesimal transformations in which the time in not variable,a new conserved quantity of holonomic mechanical systems in terms of quasi-coordinates is studied.The differential equations of motion of the systems are established.Determining equations of Lie symmetry under infinitesimal transformations are given.The Hojman theorem is generalized.Finally,an example is given to illustrate the application of the results.
Effects of strain and Mg-dopant on the photoluminescencespectra in p-type GaN
Authors: Xu Bo  , Yu Qing-Xuan  , Wu Qi-Hong  , Liao Yuan  , Wang Guan-Zhong  , Fang Rong-Chuan  ,   中国科学技术大学结构分析中心，合肥 230026;中国科学技术大学物理系，合肥 230026
Published: December 2020

The photoluminescence (PL) spectra of Mg-doped GaN on sapphire have been measured at 12K. The residual strain induced by the mismatch of the lattice constants and thermal expansion between GaN epilayers and substrates have been investigated by micro-Raman scattering and x-ray diffraction. Redshifts of the ultraviolet PL bands were observed in Mg-doped GaN after annealing in nitrogen ambient, which may be related to the carrier concentration and the strain in the epilayers. For heavily Mg-doped GaN films, the hole concentration in GaN, which shifts the PL peaks, is the dominant influence, whereas the strain is comparatively secondary.
Problems on equilibrium of a thin elastic rod constrained on a surface
Authors: Xue Yun  , Chen Li-Qun  , Liu Yan-Zhu  ,   (1)上海大学上海市应用数学和力学研究所，上海 200070; (2)上海大学上海市应用数学和力学研究所，上海 200070;上海应用技术学院机械与自动化工程学院，上海 200233; (3)上海交通大学工程力学系，上海 200030
Published: December 2020

Nonlinear mechanics of thin elastic rod, as a model of DNA, aroused extensive interest as a joint research subject of mechanics and molecular biology. The study of the equilibrium of a thin elastic rod constrained on a surface found an important application in industry, especially in molecular biology. In the present paper the constraint equations and constraint forces of the elastic rod are analyzed, and the differential/algebraic equations of equilibrium are established with the arc-coordinate of the central line as the independent variable. In a special case when the constraint surface is a cylinder the dimensionless differential equations contain only one physical parameter, the ratio of the bending and torsional stiffness of the cross section. A special solution of helical equilibrium can be derived and is corresponding to a regular precession of the Lagrange heavy rigid body about a fixed point. The numerical analysis shows that the geometrical form of the central line is dependent on the initial conditions of the rod more than its physical parameters.
Sonic point position and critical pressure ratio in non-uniform microchannels
Authors: Ding Ying-Tao  , He Feng  , Yao Zhao-Hui  , Shen Meng-Yu  , Wang Xue-Fang  ,   清华大学工程力学系,北京 100084
Published: December 2020

Non-uniform microchannels are used in the micro space propulsions and micro gas turbine generators. The performances of these applications are determined primarily by the performance of the microchannel used. Based on the micro-fabrication technology, three-dimensional rectangular cross-section straight-convergent-divergent-straight (SCDS) microchannel was fabricated. Its width in the throat cross-section was 16μm, the depth was 20μm and the contraction ratio was 1.625∶1 For different inlet-to-outlet pressure ratios, the volume flow rate characteristics of nitrogen were measured experimentally. The pressure ratios ranged from 1.0 to 4.0, outlet volume flow rate ranged from 0 to 0.12 mL/s and outlet Reynolds number was less than 350 The gas flow characteristics were analyzed by numerical simulation based on finite-volume method. Good agreements between computational results and experimental data were found. The simulation results indicate that two novel behaviors are different from that at conventional scales. One is the first sonic point position, the other is the critical pressure ratio（the critical pressure ratio is defined as the local-to-inlet pressure ratio , here the local pressure corresponding to the pressure at the first sonic point in the internal flow of SCDS microchannel）. These two novel behaviors should be attributed to the surface effects. Due to the larger surface-to-volume ratio (S/V) for microchannels, the factors related to the surface effects have more impact on the microflow. So the relationships between novel behaviors and the value of S/V are discussed further.
Applications of group theory to calculations of photonic band gap
Authors: Zhang Hai-Tao  , Gong Ma-Li  , Wang Dong-Sheng  , Li Wei  , Zhao Da-Zun  ,   (1)北京理工大学颜色科学与工程国家专业实验室，北京 100081; (2)清华大学精密仪器与机械学系，北京 100084
Published: December 2020

Group theory is introduced into the calculation of photonic band gap with the plane wave expansion method, and improved calculation formulae are derived. Both the analysis and the practical band gap calculation for an exemplary twodimensional case have shown that, as compared with the conventional plane wave method, the group theory based improved algorithm can substantially release memoryspace requirement and reduce computational time.
Harmonic signal extraction from chaotic interference based on empirical mode decomposition
Authors: Li Hong-Guang  , Meng Guang  ,   上海交通大学振动、冲击、噪声国家重点实验室，上海 200030
Published: December 2020

An approach of the harmonic signals extraction from chaotic interference is proposed. Based on empirical mode decomposition and the concept that any signals are composed of a series of the simple intrinsic modes, and the chaoic interference signals are decomposed to a series of intrinsic mode functions, the harmonic signals can be extracted. Simulation results show the approach is satisfactory.
Energy minimization control for a discrete chaotic system
Authors: Liu Ding  , Qian Fu-Cai  , Ren Hai-Peng  , Kong Zhi-Qiang  ,   西安理工大学自动化与信息工程学院,西安 710048
Published: December 2020

A general framework algorithm is proposed for energy minimization control for a discrete chaotic system. A quadratic performance function is first given and the chaotic system is decomposed into a linear and a nonlinear parts. Then, the twolevel algorithm is presented to solve the nonlinear optimal control problem: The first level predicates the nonlinear part of the chaos system; the second level solves a nonlinear quadratic optimization control problem by dynamic programming. The solution is fed back into the first level. The first level re-estimates the nonlinear part according to the solution from the second level. The information has been exchanged between the two levels by this means such that the optimal control law is obtained eventually. This method not only can make the control of chaos system be realized but also makes the energy consumed minimal during the whole control process.Simulations show the effectiveness of this algorithms.
Study on phase synchronization of chaotic oscillators with many rotational centers based on amplitude coupling
Authors: Mo Xiao-Hua  , Tang Guo-Ning  ,   广西师范大学物理与信息工程学院，桂林 541004
Published: December 2020

In order to find some relation between phase synchronization and dynamical topological variation in chaotic systems with many rotational centers,we propose a method of linear amplitude coupling to study the phase synchronization of Lorenz system and Duffing system.First,we convert the original Lorenz system and Duffing system into the dynamics of amplitude and phase.Based on linear amplitude coupling,we calculate the average winding number and Lyapunov exponents.We find that the phase synchronization comes along with the transition of Lyapunov exponents by increasing coupling strength.The results obtained indicate that phase synchronization is definitely related to dynamical topological variation in chaotic systems with many rotational centers.
A family of multiple-folded torus chaotic attractors
Authors: Yu Si-Min  , Lin Qing-Hua  , Qiu Shui-Sheng  ,   (1)广东工业大学应用物理系，广州 510090; (2)华南理工大学电子与信息学院，广州 510640; (3)广东工业大学自动化学院，广州 510090
Published: December 2020

By constructing an odd function with multiple piecewise-linear segments in the double-folded torus chaotic attractor equation and using recurrence algorithm, the recurrence formula capable of producing a family of multi-folded torus chaotic attractors is derived. Utilizing the recurrence formula thus derived and selecting properly the slope values of piecewise-linear segments, the values for equilibrium points and breakpoints are calculated. Eventually, a family of multiple-folded torus chaotic attractors can be obtained. Results of numeral simulations by using computer for generating this kind of chaotic attractors are also given.
Rough surfaces induced speckle effects on detection performance of pulsed laser radar
Authors: Guo Guan-Jun  , Shao Yun  ,   (1)中国科学院遥感应用研究所遥感信息开放实验室，北京 100101; (2)中国科学院遥感应用研究所遥感信息开放实验室，北京 100101;中国科学院空间科学与应用研究中心，北京 100080
Published: December 2020

The statistical performance of detecting optically rough surfaces with pulsed laser radar using energy detection techniques has been investigated in this paper. Under the far field condition, the analytical expressions for computing the speckle number integrated by the receiving aperture is presented, and the speckle number subtended by the telescope is found to be dependent only on the relative size of the laser beam waist and the area of the entrance pupil. A new statistics for photoelectron counts is proposed when the receiving telescope collects a large number of speckle cells and photoelectrons. The detection probabilities for airborne and spacebased laser radar have been derived. The results indicate that the laser radar performance is closely related to the speckle number observed by the receiving aperture and the influence of the speckle noise is abated with the increase of integrated speckle cells.
Equivalence of the Dirac method and the Faddeev-Jackiw method in the quantization of constrained systems
Authors: Long Zheng-Wen  , Liu Bo  , Li Zi-Ping  ,   (1)北京工业大学应用物理系，北京 100022; (2)贵州大学物理系，贵阳 550025
Published: December 2020

We have discussed the Dirac method and Faddeev-Jackiw method in the quantization of constrained systems. The equivalence of motion equation and canonical quantization in the two methods has been proved, and also the correspondence relation of constraints found.
Fuzzy control of a chaotic system based on genetic algorithm
Authors: Wu Zhong-Qiang  , Ao Dun  , Liu Kun  ,   燕山大学电气工程学院自动化系，秦皇岛 066004
Published: December 2020

We consider the fuzzy control problem of a chaotic system, based on genetic algorithm. We apply the genetic algorithm to optimize the parameters of membership function of fuzzy controller, which integrates the global searching and high precision of genetic algorithm and the celerity of the fuzzy controller. The results of simulation show the effectiveness of this method.
Ab initio study of the effects of Mg, Al dopingon the electronic structure of LiCoO2
Authors: Xu Xiao-Guang  , Wei Ying-Jin  , Meng Xing  , Wang Chun-Zhong  , Huang Zu-Fei  , Chen Gang  ,   吉林大学麦克德尔米德实验室,吉林大学材料科学与工程学院，汽车材料教育部重点实验室，长春 130023
Published: December 2020

In order to investigate the effect of Mg, Al doping on the electronic structure of LiCoO2, and to find the mechanism of high electronic conductivity in Mg-doped LiCoO2, we have carried out first-principles calculations based on density-functional theory (DFT) for LiCoO2, Li(Co, Al)O2 and Li(Co, Mg)O2 systems. Studies of band structures and densities of states show that hole states, which enhance the conductivity of semiconductor, appear in the valence bands of Mg-doped material, and the effect of charge disproportionation changes the distribution of Co-3d states in different energy levels. The ionicity of O2- increases with Mg and Al doping.
Canonical Ward identity and dynamical mass generation for Abelian gauge theory in higher-order derivative systems
Authors: Long Zheng-Wen  , Li Zi-Ping  ,   (1)北京工业大学应用物理系，北京 100022; (2)贵州大学物理系，贵阳 550025
Published: December 2020

Based on the canonical Ward-Takahashi identities to include composite fields to study gauge symmetry dynamical breaking for Abelian gauge theory in higher-order derivative systems, the mass spectra of both fermion and bound states are obtained. The effect of higher-order derivative terms on mass generation is discussed.
Dependence of isospin fractionation process on the neutron-proton ratio of a colliding system in intermediate energy heavy-ion collisions
Authors: Xing Yong-Zhong  , Liu Jian-Ye  , Guo Wen-Jun  , Fang Yu-Tian  ,   (1)天水师范学院近代物理理论研究所,天水 741000; (2)天水师范学院近代物理理论研究所,天水 741000;中国科学院近代物理研究所,兰州 730000;中国科学院兰州重离子加速器国家实验室原子核物理理论中心,兰州 730000; (3)中国科学院近代物理研究所,兰州 730000
Published: December 2020

The degree of isospin fractionation is measured by the ratio of saturated neutron-proton:i.e. the ratio of gas phase (nucleon emission) to that of liquid phase (fragment emission) in heavy ion collisions. We have studied the dependence of the degree of isospin fractionation on the neutron-proton ratio in the colliding system by using isospin-dependent quantum molecular dynamical model. The calculated results show that the degree of isospin fractionation depends sensitively on the symmetry potential and weakly on the isospin effect of nucleon-nucleon cross section. In particular, the degree of isospin fractionation increases with increasing neutron-proton ratio in the colliding system for the neutron-rich system, in this process the neutron-rich gas phase and neutron-poor liquid phase are produced. The degree of isospin fractionation is very sensitive to the degree of symmetry potential. On the contrary, for the neutron-poor system the neutron-poor gas phase and neutron-rich liquid phase are produced. In this case, the degree of isospin fractionation is not sensitive to the symmetry potential. We also find that the role of momentum dependent interaction in the isospin fractionation process is not obvious. We propose that our calculated results can compare directly with the experimental data to get the information about the symmetry potential in the intermediate energy heavy-ion collisions.