bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigation on turbulent channel flow utilizing spanwise oscillating Lorentz force
Authors: Mei Dong-Jie  , Fan Bao-Chun  , Chen Yao-Hui  , Ye Jing-Fang  ,   Science and Technology on Transient Physics Laboratory, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

Experimental investigation on the effect of using spanwise oscillating Lorentz force to control near-wall turbulence is presented in this paper. The effects of spanwise oscillating Lorentz force on macroscopic flow field, near-wall coherent structure and skin friction are discussed. Direct numerical simulation is carried out to verify the experimental results. The results from experiment and numerical simulation suggest that the spanwise oscillating Lorentz force can make the macroscopic flow field oscillating periodically, the streak structures are twisted into the spanwise direction and the skin friction is reduced.
Quantized energy spectrum and exact wave function of three-dimensional anisotropic coupled harmonic oscillator
Authors: Ling Rui-Liang  , Feng Jin  , Feng Jin-Fu  ,   (1)School of Mathematics and Statistics, Changshu Institute of Technology, Changshu 215500, China; (2)School of Physics and Electronic Engineering, Changshu Institute of Technology, Changshu 215500, China
Published: December 2020

By the quadratic form theory, we succeed in diagonalizing the Hamiltonian for three-dimensional anisotropic coupled harmonic oscillators, through three symplectic transformations keeping the commutation relations unchanged. The quantized energy spectrum and the exact wave function of the system are given.
Effect of frictional force on subharmonic bifurcations of a completely inelastic ball bouncing on a vibrating table
Authors: Jiang Ze-Hui  , Guo Bo  , Zhang Feng  , Wang Fu-Li  ,   Department of Physics, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

The behavior of a completely inelastic ball bouncing on a vertically vibrating table in the presence of frictional force is investigated. The frictional force is assumed to be constant. It is found that the sequence of bifurcation, controlled solely by the normalized vibration acceleration Γ, is the same as that in the absence of frictional force, but the value of each bifurcation point becomes larger. In the bifurcation diagram of ball flight time, the structure consisting of an infinity of bifurcation cascades in a narrow range of Γ is observed. Compared with that of no frictional force, it is longitudinally compressed and transversely stretched, and has a different fractal property. A comparison with the bifurcations observed in vertically vibrated granular beds is also made. When the fractional force is set to be 20%—30% of the whole weight of the particles, the results from the bouncing ball model are in good agreement with experimental observations.
178Hfm2 isomer prepared by the bombardment of energetic α particles on metallic Yb foil
Authors: Ze Ren-De  , Yang Tian-Li  , Xiong Zong-Hua  , Hao Fan-Hua  , Yang Chao-Wen  ,   (1)Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China; (2)Key Laboratory of Radiation Physics and Technology of Ministry of Education, School of Physical Science and Technology, Sichuan University, Chengdu 610045, China
Published: December 2020

In this paper the 178Hfm2 isomer prepared through the bombardment of 27MeV α particles on natural metallic Yb foil in the CS30 cyclotron has been studied. Analysising the γ spectrum of sample irradiated by α particles, the amount of178Hfm2 isomer can be determined to be about 1.5×1011 nuclei, the main long-lived isomers of sample are identified and the possible reaction paths of these isomers are deduced. By monitoring the radioactivity dose of sample, the cooling time for chemical separation is also obtained. The preliminary results are conducive to further developing the method of 178Hfm2 isomer production.
Dynamics of Bell nonlocality in non-degenerate two-photon Jaynes-Cummings model
Authors: Liao Chang-Geng  , Chen Zi-Hong  , Luo Cheng-Li  ,   College of Physics and Information Engineering, Fuzhou University, Fuzhou 350002, China
Published: December 2020

We investigate quantum nonlocality dynamics of a three-level atom and a class of two-mode non-classical states (including the entangled coherent state, the pair coherent state and the two-mode squeezed state) in the non-degenerate two-photon Jaynes-Cummings model. It is shown that the time evolution of the Bell nonlocality for the case of the entangled coherent state is closely related to the average number of photons in the two-mode field. For the cases of the pair coherent state and the two-mode squeezed state, the effect of Bell nonlocality sudden death is demonstrated, and the absolute value of the 〈BCHSH〉 exhibits exact periodic collapses and revivals.
Optimization of attosecond pulses from the interaction of ultrarelativistic laser with overdense plasma
Authors: Luo Mu-Hua  , Zhang Qiu-Ju  , Yan Chun-Yan  ,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

Using one-dimensional particle-in-cell simulations, the generation of attosecond pulses is studied due to the interaction of a short ultrarelativistic laser pulse with overdense plasma. According to the ultrarelativistic similarity theory, we analyze the motion of the electrons and the generation of high-order harmonics. We find that when the plasma density is constant and the dimensionless similarity parameter S decreases, the conversion efficiency of attosecond pulses first increases and then decreases. So we can choose a laser pulse with an appropriate intensity to obtain an attosecond pulse with a high conversion efficiency. Furthermore, when S is fixed, with the increase of the plasma density, the conversion efficiency of attosecond pulses shows an upward tendency. This implies that we can obtain a higher attosecond pulse when a laser with an appropriate intensity is incident on a denser plasma.
Theory of Fourier mode coupling for fiber Bragg gratings
Authors: Rao Yun-Jiang  , Zeng Xiang-Kai  ,   (1)Key Laboratory of Manufacture and Test Techniques for Automobile Parts of Ministry of Education, School of Electronic Information and Automation, Chongqing University of Technology, Chongqing 400050, China; (2)Key Laboratory of Optoelectronic Technology and Systems of Ministry of Education, Chongqing University, Chongqing 400044, China;Key Laboratory of Optical Fiber Sensing and Communications of Ministry of Education, University of Electronic Science and Techn
Published: December 2020

A novel theory, namely, Fourier mode coupling (FMC) theory for fiber Bragg gratings (FBGs) is proposed in this paper. During analyzing coupled modes of FBGs, the Fourier transform relations among the amplitude coefficients of coupled modes are found for the first time. The general expressions of reflective and transmissive spectra of FBGs are deduced from the combination of Fourier transform with the well-known coupled-mode theory. In the proposed FMC theory, the spectral characteristics of the FBG are achieved by the calculation of coupled modes in the spatial domain spectrum, which is the Fourier transform result of refractive index perturbation in the FBG. The FBG spectrum based on the FMC theory is simulated here, and compared with those obtained from the coupled mode theory and pure Fourier transform. The comparison shows that the FMC theory for and the derived spactra of FBGs are in accordance with the coupled mode theory and the practical spectra of the FBG respectively. The FMC theory has many features, these being simple, clear, direct, accurate and fast, which could be used as a universal tool for fast spectrum analysis of any FBG with an arbitrary distribution of refractive index perturbation along the fiber axis.
Theory of Fourier mode coupling for long-period fiber gratings
Authors: Rao Yun-Jiang  , Zeng Xiang-Kai  ,   (1)Key Laboratory of Manufacture and Test Techniques for Automobile Parts of Ministry of Education, School of Electronic Information and Automation, Chongqing University of Technology, Chongqing 400050, China; (2)Key Laboratory of Optoelectronic Technology and Systems of Ministry of Education, Chongqing University, Chongqing 400044, China;Key Laboratory of Optical Fiber Sensing and Communications of Ministry of Education, University of Electronic Science and Techn
Published: December 2020

A novel theory, namely, Fourier mode coupling (FMC) theory for long-period fiber gratings (LPFGs) is proposed in this paper. During analyzing the co-propagating coupling between the core mode and cladding modes in LPFGs, the Fourier transform relations among the amplitude coefficients of co-propagating coupled-modes are found for the first time, to the best of authors’ knowledge. The general expressions of the coupling and transmission spectra of LPFGs are also deduced from the combination of Fourier transform with the well-known coupled-mode theory. In the proposed FMC theory, the spectral characteristics of the LPFGs without over-coupling are derived from the calculation of co-propagating mode coupling in the spatial domain spectrum, which is the Fourier transform result of refractive index perturbation in the LPFG. According to the FMC theory, the spectra of the LPFGs in different perturbation amplitudes and lengths are numerically simulated here. A measured transmission spectrum is also compared with the calculated transmission spectra based on the FMC theory and the coupled mode theory, respectively. The comparison shows that the FMC theory and the derived spectra for LPFGs are in consistance with the coupled-mode theory and the practical spectra of LPFGs respectively. The FMC has many features, these being simple, fast and accurate, which could be employed for spectrum analysis of any LPFG with an arbitrary distribution of refractive index perturbation along the fiber axis.
Mid-infrared hollow-core Bragg fiber for trace gas detection
Authors: Xing Wen-Xin  , Zhang Wei  , Shi Li-Chao  , Wang Wen  , Zhao Hong  , Li Zhi-Guang  , Huang Yi-Dong  , Peng Jiang-De  ,   (1)Beijing Glass Research Institute, Beijing 101111, China; (2)Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

Bragg fiber is one kind of microstructure fiber with one-dimensional photonic crystal layer in its fiber cladding. In this paper, the hollow-core Bragg fiber for trace gas detection, with a transmission band in the mid-infrared band, is designed and fabricated based on semiconductor glass and polymer materials. The measurements of the fiber sample demonstrate its bandgap-guided properties, showing two obvious bandgap guided transmission bands. The central wavelength of the lowest transmission band is 4.4 μm.
Elastic waves in Maxwell fluid-saturated porous media with the squirt flow mechanism
Authors: Cui Zhi-Wen  , Liu Jin-Xia  , Wang Chun-Xia  , Wang Ke-Xie  ,   School of Physics, Jilin University, Changchun 130012, China
Published: December 2020

Based on Biot-Tsiklauri model and the combined Biot/squirt model, a universal acoustic model for non-Newtonian fluid (Maxwell fluid) saturated porous medium with an arbitrary pore size distribution is presented, in which the squirt-flow mechanism has been taken into account. The influences of non-Newtonian effect of Maxwell fluid on the attenuation and the dispersion characteristics of elastic waves propagating in such a porous medium are investigated. It shows that the non-Newtonian effect and the squirt-flow effect are the important factors for elastic wave dispersion and attenuation. When the squirt flow mechanism occurs, the squirt flow mechanism dominates the contribution to the energy loss of compressional waves at low frequencies. It shows that the squirt flow only affects the dispersion and the attenuation characteristics of two compressional waves, while the non-Newtonian effect of Maxwell fluid not only affects the dispersion and the attenuation characteristics of the compressional waves, but also influences the dispersion and the attenuation characteristics of shear waves.
Two-phase frictional pressure drop of 1,1-difluoroethane in a horizontal tube
Authors: Chen Gao-Fei  , Gong Mao-Qiong  , Shen Jun  , Zou Xin  , Wu Jian-Feng  ,   (1)Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China; (2)Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China;Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

This paper deals with an experimental investigation of two-phase frictional pressure drop behavior of 1,1-difluoroethane in an 8 mm inside-diameter smooth horizontal tube. Pressure drop characteristics are measured in a pressure range of 0.19—0.41 MPa, heat flux range of 14—62 kW/m2, and mass flux range of 128—200 kg/m2s. The effects of experimental parameters on pressure drop are analyzed. It is found that with the increases of mass flow and vapor quality, the frictional pressure drop increases. The proportion of momentum pressure drop in the total pressure drop increases slightly as heat flux increases, and accordingly the proportion of the frictional pressure drop decreases. The frictional pressure drop increases with saturation pressure decreasing. Experimental results are compared with the calculations from the two extensively used correlation formulae. Our investigations show that the Friedel model has a relatively large deviation, and the Müller-Steinhagen-Heck model accords well with the experimental results.
Simulation of planar wire array Z-pinch based on single wire behavior
Authors: Wang Liang-Ping  , Han Juan-Juan  , Wu Jian  , Guo Ning  , Wu Gang  , Li Yan  , Qiu Ai-Ci  ,   Northwest Institute of Nuclear Technology, Xi'an 710024, China
Published: December 2020

Planar wire arrays have been widely studied as a kind of non-cylindrical wire array load in recent years. In this paper the magnetostatic simulation of individual wire in a planar wire array is performed using a radial motion equation in order to understand the patterns of the current partition through the wires, the force distribution on the individual wire, the magnetic field distribution on the planar wire array, and the variations of the total load inductance and the kinetic energy of the wire array during the implosion phase. The model has also been used to calculate the implosion trace and time of the planar wire array used on "Qiangguang-Ⅰ" generator. The calculation results are compared with the experimental results and it is concluded that the model gives an implosion time with an error of about 10%. All the simulation results mentioned above can help one further understand the process of the planar wire array Z-pinch and design the load parameters.
Numerical simulation analysis of Z-pinch implosion using MARED code
Authors: Ding Ning  , Wu Ji-Ming  , Dai Zi-Huan  , Zhang Yang  , Yin Li  , Yao Yan-Zhong  , Sun Shun-Kai  , Ning Cheng  , Shu Xiao-Jian  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
Published: December 2020

To develop reliable numerical simulation tools is very important for the theoretical research, the experimental analysis and the load designing of Z-pinch implosions. A dedicated Z-pinch implosion physical scheme of the two-dimensional numerical simulation of three-temperature radiation magnetohydrodynamics MARED code is introduced. The results of its one-dimensional test demonstrate that the MARED code is suited for simulating implosions on different devices and in a wide range of load parameters. A combination between the simulations and the measurements of the wire-array Z-pinch experiment shows that under the same load conditions, the X-ray radiation power produced by the tungsten wire-array implosion is much higher than that generated by the aluminum wire array. With the same load current, a greater load mass gains a lower X-ray power. However, the X-ray radiation power increases with the load current. The MARED code is found to be able to reproduce the primary dynamic characteristics of the Z-pinch implosions, and the development of the instability qualitatively aecords with the simplified instability theoretical analysis and experimental results. It is also used to simulate the radiation field formation of the wire-array with filling column at the axis, and its preliminary results are qualitatively consistent with the simulation results from the Sandia laboratory.
High pressure phase transition and phonon-dispersion relations of BeO calculated by first-principles method
Authors: Yuan Peng-Fei  , Zhu Wen-Jun  , Xu Ji-An  , Liu Shao-Jun  , Jing Fu-Qian  ,   Department of Physics, Beijing Normal University, Beijing 100875, China;,   Key Laboratory of National Defense Science and Technology for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China;,   Key Laboratory of National Defense Science and Technology for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China;School of Physical Science and Technology, Sichuan University, Chengd
Published: December 2020

The high pressure phase transition at zero temperature and the phonon-dispersion relations at zero temperatue and zero pressue of BeO have been studied by a first-principles method. The results show that a phase transition from wurtzite structure (B4) to cubic sodium chloride structure (B1) happens at about 122 GPa and the zinc blende phase (B3) is of a meta-stable structure at zero temperature and zero pressure. The phonon-dispersion relations of B1, B3 and B4 phase BeO at zero temperature and zero pressure are investigated by the frozen phonon method. The calculations show that at zero temperature and zero pressure B1 phase is an unstable phase and B4 and B3 phases are of two very simliar structure, but they are still distinguishable from each other by their phonon-dispersion relations. Finally, the phase diagrams of BeO at high temperature and high pressure are studied.
Mechanism of large grain polycrystalline Si preparation by aluminum induced crystallization with temperature gradient profile
Authors: Tang Zheng-Xia  , Shen Hong-Lie  , Jiang Feng  , Fang Ru  , Lu Lin-Feng  , Huang Hai-Bin  , Cai Hong  ,   College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Published: December 2020

In order to shorten processing time for large grain polycrystalline Si thin films prepared by aluminum induced crystallization, the stack of a-Si/SiO2/Al is deposited by radio frequency magnetron sputtering and annealed at two different irregular temperature profiles. The influence of irregular temperature profile on the processing of amorphous silicon prepared by the aluminum induced crystallization is investigated and the condition is discussed under which whether new nucleation appears when the annealing temperature increases. It turns out that the formation of nucleation is governed by the relationship among the grain radium at low temperature, the distance of depletion region, and the distance of adjacent grains.
Molecular dynamics simulation of low-energy bombardment on Pt(111) surface
Authors: Yan Chao  , Duan Jun-Hong  , He Xing-Dao  ,   Key Laboratory of Nondestructive Testing of Ministry of Education, School of Measuring and Optical Engineering, Nanchang Hangkong University, Nanchang 330063, China
Published: December 2020

The low-energy bombardments of noble metal atoms (Ni, Pd, Pt, Cu, Ag, Au) on Pt (111) surface are studied by molecular dynamics (MD) simulations. The atomic interaction potential with embedded atom is used in the simulation. The incident-energy effects on adatom yields, sputtering yields, and vacancy yields for different projectiles have been observed and summarized. When the incident energy Ein varies from 0.1 to 200 eV, surface atoms transfer layer by layer and the incident energy dependent transition occurs when the incident energy values are about 5 and 70 eV. When the incident energy is lower than 5 eV, projetiles are deposited as adatom and the value of defect yield is 0. While 70 eV > Ein > 5 eV, no atoms can be implanted into the depth beyond the second layer and the vacancy yield in the third layer is about 0. For the case of Ein > 70 eV, deposited atoms enter into the third layer. And then, vacancy occurs. Furthermore, defect yield sharply increases with the increase of incident energy. Based on the result of our MD simulations, a guide to the choice of optimum deposition parameters is suggested.
Effects of synthesis parameters on the growth of magnesium oxide nanowries by vapor-liquid-solid mechanism at low temperatures
Authors: Lai Yun-Feng  ,   Institute of Micro-Nano Devices and Solar Cells, School of Physics and Information Engineering, Fuzhou University, Fuzhou 350108, China
Published: December 2020

MgO nanowires are synthesized at a lower temperature (T=600 ℃) by pulsed liquid injection metal-organic chemical vapor deposition with Mg(C11H19O2)2 (magnesium bis (2, 2, 6, 6-tetramethyl-3, 5-heptanedionate)) as precursor. The MgO nanowires grow along the [001] direction with gold nanoparticles on the tips, which leads to the vapor-liquid-solid growth mechanism. The growth mode of nanowires (vertical growth to the substrate or parallel growth to the substrate) can be controlled by adjusting the injection period or the injection mass/period.
Effects of impurity on negatively charged exciton on quantum ring
Authors: Wu Hong  ,   Department of Physics, Jimei University, Xiamen 361021, China
Published: December 2020

The effects of the impurity on the energy-optical spectrum and the Aharonov-Bohm oscillation of the negatively charged exciton X－ on the quantum ring are discussed. In the present case, the total orbital angular momentum is not conserved. To find the wave function, a set of basic functions is formed according to their total orbital angular momenta. Then the typical diagonalization method is used to find the eigenvalues and the eigen functions of the system. The calculated results are satisfactory. When the impurities are not in the x-y plane, the calculation skill using the equivalent charge transformation formula becomes simple and charts are also discussed.
Bipolaron mechanism of DX center in AlxGa1-xAs:Si
Authors: Liang Ying-Xin  , Li Wei-Feng  , Wei Jian-Hua  , Jin Yong  ,   (1)Department of Physics, Renmin University, Beijing 100872, China; (2)Laboratory for Photonics and Nanostructures, National Center of Science Research, Marcoussis 91460, France
Published: December 2020

The free-carrier concentration in Si-doped AlxGa1-xAs has been calculated by grand-canonical-ensemble statistics without any fitting parameters. Our results are quantitatively in agreement with various experimental data in the temperature range 77—300 K, which indicates that the physical picture of the ground state of DX center (DX-) is of an electronic bipolaron due to the interaction between excess electrons and lattice. When exposed to light, one bipolaron can turn into a polaron, meantime release one electron to the conduction band accompanied by lattice relaxations. Our calculations also prove that DX0 is unstable at thermal equilibrium, which further confirms our bipolaron mechanism.
Effect of Schottky barrier on spin injection in ferromagnetic/organic semiconductor structure
Authors: Xiu Ming-Xia  , Ren Jun-Feng  , Wang Yu-Mei  , Yuan Xiao-Bo  , Hu Gui-Chao  ,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

Theoretically we have studied the current spin polarization in the structure of ferromagnetic/organic semiconductor under Schottky contact and discussed its variations with potential barrier height, the special carriers in organic semiconductor layer and the its mobilities, doping concentration near the interface. The calculations show that the high mobilities of the carriers in organic semiconductors are conducive to the spin injection. We also find that a significant depletion region at Schottky contact is highly undesirable for spin injection. For an efficient spin injection, the depletion region near the interface should be heavily doped and the effective barrier height should be restricted wichin certain range.
Threshold voltage analytic model for strained SiGe-on-insulator p-channel metal-oxide-semiconductor-field-effect-transistor
Authors: Liu Hong-Xia  , Yin Xiang-Kun  , Liu Bing-Jie  , Hao Yue  ,   Key Laboratory for Wide Band Gap Semiconductor Materials and Devices of Ministry of Education, School of Microelectronics, Xidian University, Xi’an 710071, China
Published: December 2020

This paper investigates the threshold voltage analytic model of strained SiGe-on-insulator p-channel metal-oxide-semiconductor-field-effect-transistor (SGOI pMOSFET), revises the energy band model of strained-silicon, and extracts the main physical parameters of strained-SiGe devices. These parameters include the energy gap, electron affinity, build-up potential, etc. In this paper, the two-dimensional Possions equation of build-in potential in strained silicon SGOI pMOSFET is also presented. By using the boundary conditions to solve these equations, an accurate threshold voltage analytic model is proposed and its validity is verified.
Ferroelectric polarization reversal behavior in 63PbTiO3-37BiScO3 bulk ceramics
Authors: Yu Gang  , Dong Xian-Lin  , Wang Gen-Shui  , Chen Xue-Feng  , Cao Fei  ,   Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
Published: December 2020

The ferroelectric hysteresis loops of 63PbTiO3-37BiScO3 ceramics are measured under sinusoidal electric field varying from 5 to 55 kV/cm in a frequency range from 0.1 to 100 Hz. The fitting results show that the logarithm of remanent polarization and the logarithm of coercive electric field are both linearly related to electric field in the first and third field regions, but not in the second region. The three-stage behavior is distinct from the existing two-stage behavior, and it can be attributed to the dependence of ferroelectric polarization behavior on field stage.
Thermodynamics of the Schwarzchild-de Sitter black hole
Authors: Zhang Li-Chun  , Li Huai-Fan  , Zhao Ren  ,   Institute of Theoretical Physics, Department of Physics, Shanxi Datong University, Datong 037009, China
Published: December 2020

Considering the fact that there is a correlation between the black hole horizon and cosmological horizon, we show that the thermodynamic entropy of de Sitter spacetime is the sum of thermodynamic entropies of the black hole horizon and cosmological horizon. The thermodynamic properties of de Sitter spacetime are also derived. It is shown that the upper limit energy of de Sitter spacetime is equal to the energy of pure de Sitter spacetime, The thermal capacity of de Sitter spacetime is negative, so de Sitter spacetime is mechanically unstable.
Matched asymptotic solution to a class of singularly perturbed thin plate bending problem
Authors: Chen Li-Hua  , Xu Hui  , Mo Jia-Qi  ,   School of Statistics & Applied Mathematics, Anhui University of Finance and Economics, Bengbu 233030;,   Department of Mathematics, Anhui Normal University, Wuhu 241003, China;,   ChinaDepartment of Mathematics and Computer Science, Fuqing Branch of Fujian Normal University, Fuqing 350300, China
Published: December 2020

The thin plate-bending problem is studied. Introducing the stretched variables, the internal layer solutions near the boundary are constructed for the fourth order singularly perturbed boundary problem. Then matching the solutions with outer solution and using the theory of the composite expansion, the asymptotic solution is obtained finally.
Numerical investigation of x-ray energy spectrum of rod-pinch diode
Authors: Zhang Peng-Fei  , Su Zhao-Feng  , Sun Jian-Feng  , Yang Hai-Liang  , Li Yong-Dong  , Gao Yi  , Sun Jiang  , Wang Hong-Guang  , Yin Jia-Hui  , Liang Tian-Xue  , Sun Feng-Ju  , Wang Zhi-Guo  ,   Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China;,   Northwest Institute of Nuclear Technology, Xi'an 710024, China
Published: December 2020

By particle-in-cell (PIC) simulation and theoretically analysis, electron spatial distribution and energy distribution in the rod surface of rod-pinch diode(RPD) are obtained separately, as input parameters for Monte Carlo simulation of photon energy spectrum of X-ray emitted from RPD. The Monte Carlo simulation results show that the average photon energy of shot 09006 is 0.441 MeV. Taking account of Pb attenuator, the simulation results accord with experiment data detected by PIN detectors array.
Nonorthogonal passive decoy-state quantum key distribution with a weak coherent state source
Authors: Zhou Yuan-Yuan  , Zhou Xue-Jun  ,   Department of Communication Engineering, School of Electronic Engineering, Naval University of Engineering, Wuhan 430033,China
Published: December 2020

A nonorthogonal passive decoy-state method is presented with a reconstructive weak coherent state source. The method dose not prepare decoy states actively and divides the receiver detection events into two groups, i.e., triggered components and nontriggered components, according to triggering situation of the sender detector. Both triggered and nontriggered components, as signal states and decoy states, are used to do some estimations and to generate secure key. The simulation results show that a better key generation rate and a longer secure transmission distance can be obtained with the nonorthogonal passive decoy-state method than with the existing passive methods, and that the performance is comparable to the theoretical limit of an active infinite decoy-state protocol. Furthermore, the nontriggered component contribution to key generation offsets the limitation of the detector low efficiency, and the performance of the method dose not depend on the detector efficiency of sender. Because decoy states need not be prepared actively, and our protocol is easy to implement and apply to quantum key distribution at high transmission rates.
Synchronization of new Lü chaotic system via three methods
Authors: Wang Xing-Yuan  , Zhu Quan-Long  , Zhang Xiao-Peng  ,   Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024, China
Published: December 2020

In this paper we study the chaos synchronization of a new Lü chaotic system containing constants via three methods, i.e., state observer, active control method, and backstepping method. Based on the above three methods, the we design an adaptive controller according to the Lyapunov stability theory which proves that the controller can well realize the asymptotical synchronization between two identical systems. Through numerical simulation, we further verify the effectiveness and the advantage of the above three synchronization methods. The synchronization method based on state observer is believed to be more flexible and efficient through the comparative analysis of three kinds of synchronization methods.
Measurement of velocity distribution for strontium atom beam by Zeeman Scanning technology
Authors: Wang Xin-Liang  , Chen Jie  , Wang Ye-Bing  , Gao Feng  , Zhang Shou-Gang  , Liu Hai-Feng  , Chang Hong  ,   National Time Service Center, Chinese Academy of Science, Xi'an 710600, China;,   Graduate University of Chinese Academy of Science, Beijing 100049, China
Published: December 2020

We measure the velocity distribution of the strontium atomic beam directly by Zeeman scanning technology. The most probable velocities of atomic beam before and after Zeeman deceleration are 420 m/s and 60 m/s respectively. Zeeman scanning method is much convenient than other detect ways. Because of its direct fluorescence observation, it has a high accuracy relatively.
Chromium atom deposition in elliptical standing wave filed
Authors: Zhang Wen-Tao  , Zhu Bao-Hua  , Huang Jing  , Xiong Xian-Ming  ,   Guilin University of Electronic Technology, Guilin 541004,China;,   Guizhou University for Nationalities, Guiyang 550000,China
Published: December 2020

Direct-write atom lithography is a new technique in which resonant light is used to pattern an atomic beam and the nanostructures are formed when the atoms deposit on a substrate. The motorial characteristics of chromium atoms in an elliptical standing wave filed are discussed, and the simulation results are given with different deflective angles of elliptical standing wave. The full width at half maximum (FWHM) is 3.2 nm and the contrast is 36 ∶1 with a deflective angle of 0. The FWHM is 6.5nm and the contrast is 24 ∶1 with a deflective angel of 15, but when the deflective angle reaches 30, the stripe splits and two-peak configuration is formed.
Influential factors of time reversal Mirror on focusing property of time-reversed electromagnetic wave
Authors: Ding Shuai  , Wang Bing-Zhong  , Ge Guang-Ding  , Wang Duo  , Zhao De-Shuang  ,   Institute of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

The main influential factors on focusing property of time-reversed electromagnetic wave come from time reversal mirror (TRM). The various influential factors are analyzed by using electromagnetic simulation tools. Then method of improving the focusing property of time-reversed electromagnetic wave is proposed. Finally, the method of improving the performance is verified in experiment.
Control and synchronization of phase-conjugate wave spatiotemporal chaos system driven by CO2 laser
Authors: Zhu Jin-Chuan  , Li Chen-Ren  , Qi Jia-Yu  , Ren Xu-Dong  , Yue Xi-Shuang  ,   College of Physics and Electronic Technology , Liaoning Normal University , Dalian 116029 , China
Published: December 2020

Taking an one-dimensional coupled map lattice as an object, the characteristics of phase-conjugate wave spatiotemporal chaos system are investigated. Based on the Lyapunov stable theorem, the control of phase-conjugate wave spatiotemporal chaos system is achieved, and the multiple phase-conjugate wave spatiotemporal chaos system is driven into the parallel synchronization by the CO2 laser through choosing the coupling parameter. Numerical simulation results show that the coupling parameter has influence on the control and the synchronization speed of the phase-conjugation wave spatiotemporal chaos system. The greater the coupling parameter, the shorter the synchronization timeis.
Proposal of novel and efficient polarization beam splitter
Authors: Zhang Xuan  , Liao Qing-Hua  , Chen Shu-Wen  , Hu Ping  , Yu Tian-Bao  , Liu Nian-Hua  ,   Department of Physics, Nanchang University, Nanchang 330031, China
Published: December 2020

We study and analyze the propagation and the characteristics of light in structure, and find that by increasing the sizes of air holes in the two rows that are adjacent to the middle slab, there appears only one polarization state that can propagate in the waveguide within the complete photonic band gap at a specific frequency. Then we propose a new structure of polarization beam splitter based on the principle. The results of calculation and simulation show that the device can separate TE mode from TM mode effectively with a large angle. And the device size is less than 17.6μm×9.8μm.We believes that it will have potential applications in the photonic integrated circuits.
Intensity-modulated bending sensors based on rare-earth-doped fibers
Authors: Liu Yu  , Zeng Liao-Liao  , Lu Yong-Le  , Liu Shen  , Huang Zhao-Jing  ,   Institute of Optical Communication Technology, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
Published: December 2020

A novel periodic micro-tapering glass fiber based on rare-earth-doped glass fiber and its bending sensor application are investigaled. The material of fiber consists of two types of lead silicate glasses, one is for core, and the is for cladding. And it has the performances of good plasticity and easy taper. The key body of the sensor is made of the rare-earth-doped fiber which is heated by the focused CO2 laser beam in periodic and equal spacing. In this paper we constructe an intensity modulated bending sensor measurement system based on the sensor body, high resolution moving platform and optic testing platform. Principle research and experiment testing show that the designed bending sensor measurement unit has a high bending sensitivity of -28.2W/m and a low measurement error of lass than ± 1%, which is of significance for possible applications in engineering.
Using delayed feedback to control the band of saturation control in an auto-parametric dynamical system
Authors: Zhao Yan-Ying  , Yang Ru-Ming  ,   School of Aircraft Engineering, Nanchang Hangkong University, Nanchang 330063, China
Published: December 2020

We investigate the band of the saturation control in an auto-parametric dynamical system by using the delayed feedback. In an original system without delay feedback, some unstable regions may occur in the band of the saturation control for some internal resonance detuning parameters. The band of the saturation control is distributed unreasonably. The delay feedback control is used to control the distribution of the band for saturation control. The effects of the gain and delay on the band of the saturation control are studied. The results show that the unstable regions of the saturation control can be eliminated by choosing the values of the gain and delay appropriately. Moreover, the bandwidth of the saturation control does not narrow. Consequently, the distribution band of the saturation control can be improved by using the delay feedback control.
Design of X-band backward wave oscillator with 10 GW output power
Authors: Ma Qiao-Sheng  , Jin Xiao  , Xu Ming  , Li Zheng-Hong  , Wu Yang  ,   中国工程物理研究院环保工程研究中心,绵阳 621900;,   Institute of Applied Electronics, CAEP, Mianyang 621900, China
Published: December 2020

An efficient high power relativistic backward wave oscillator (RBWO) is designed. To enhance the beam-wave conversion efficiency and output power, an overmoded slow wave structure (SWS) is used and an inner conductor is inserted into the SWS. When electron energy is 1.3 MeV while the beam current is 17 kA, the simulated output microwave power is 10.4 GW at 8.8 GHz frequency for the RBWO.
Theoretical and numerical study on optimization of diode parameters in virtual cathode oscillator
Authors: Liu Jing  , Shu Ting  , Li Zhi-Qiang  ,   College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073, China
Published: December 2020

The dependences of microwave efficiency and frequency on the parameters of diode in virtual cathode oscillator (VCO) are studied with particle-in-cell simulations, which further gives the effects of diode impedance on microwave efficiency and frequency. The characteristic impedance of microwave mode in virtual cathode oscillator is derived as in other high power microwave generators with slow-wave configurations and is used to analyze the optimization of diode parameters. It is shown that the optimal values of diode parameters are obtained when the diode impedance matches with the characteristic impedance of microwave mode in VCO with coaxial wave guide as well as in VCOs with other configurations. This is a good theoretical explanation for the optimization of diode in VCO and can be used to guide the design of devices.
Theoretical research of TiO2 adsorption on GaN(0001) surface
Authors: Huang Ping  , Yang Chun  ,   Visual Computing and Virtual Reality Key Laboratory of Sichuan Province,Sichuan Normal University, Chengdu 610068, China;,   College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China
Published: December 2020

The adsorption of molecule TiO2 on GaN(0001) surface is theoretically explored by using a plane wave ultrasoft pseudo-potential method based on the density functional theory. The bonding processing of TiO2molecule on the surface of GaN(0001), the adsorption energy, and the adsorption orientation are investigated. The results indicate that Ti atom is adsorbed on fcc site or on hcp site, and two O atoms are combined with two Ga atoms on the GaN surface after adsorption. The chemical bonding of GaO shows a covalent feature, and the chemical bonding energy is achieved to be 7.9327.943 eV. The OO line directions lie along the GaN [1120] directions, in accordance with experimental reports of (100) [001] TiO2// (0001)[1120] GaN. From ab initio dynamics calculation, the adsorption process can be divided into physical adsorption, chemical adsorption and superficial stable state,and the stable adsorption site is in accordance with the optimized results.
First principles study of the electronic structure and photoelectric properties of rutile vanadium dioxcide
Authors: Su Rui  , He Jie  , Chen Jia-Sheng  , Guo Ying-Jie  ,   College of Physics Science and Technology,Sichuan University,Chengdu 610064, China
Published: December 2020

The electronic structure and the photoelectric properties of rutile based VO2 are investigated using the FP-LAPW method which is combined with the DFT+U method. The calculated density of statas (DOS) shows that the DFT+U method can describe the conductive band properly. The V-O bonding in VO2 is induced mainly through the strong hybridization of V3d orbital and O2p orbital. The calculated plasma frequency is 3.44 eV when the applied light field is perpendicular to the c axis and 2.74 eV when the applied light field is along the c axis. The optical conductivity spectrum shows a Drude-like peak is between 0 eV and 1 eV while in upper area the interband contribution is more important. Finally, the reflection spectrum and the election energy loss spectrum (EELS) are calculated and analyzed.
p-type transparent conductive BaSnO3: A first-principles calculations
Authors: Tan Xing-Yi  , Chen Chang-Le  , Jin Ke-Xin  ,   Shannxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University,Xi'an 710129, China
Published: December 2020

Based on density functional theory calculations, the electronic properties of N-doped BaSnO3 and N and Sb codoping are investigated. It is found that codoping with N acceptors and Nb donors in a ratio of 2 ∶1 is suitable for the fabrication of low-resistivity p-type BaSnO3. Our results indicate that codoping with N acceptors and Nb donors is a prospective candidate as a p-type transparent conductive material.
Investigation on the low-freauency noise physical models and the defects' characterization of the PbS infrared dectector
Authors: Chen Wen-Hao  , Du Lei  , Yin Xue-Song  , Kang Li  , Wang Fang  , Chen Song  ,   School of Technology Physics, Xidian University,Xi'an 710071, China;,   Shaanxi Huaxing Electronics Group co.,LTD, Xianyang 712099, China
Published: December 2020

In order to characterize the defects of PbS thin film photoconductive infrared detector materials, The physical model of 1/f noise and g-r noise are deduced and verified. The surface trap densities under different voltages are calculated by the relation between 1/f noise and surface trap in this model. The phenomenon that the surface trap density increases with bias voltage is observed. Therefore, the conclusion that 1/f noise is proportional to bias voltage is drawn, and it is consistent with the experimental measurements. In addition, the relation between g-r noise and deep-level defect characterization parameters is investigated based on this model, and the method of using low frequency noise to characterize defect parameters including defect activate energy, degeneracy factor and capture section is presented.
Structural phase transition and magnetic properties of Co50Fe50-xSix alloys
Authors: Zhao Jing-Jing  , Shu Di  , Qi Xin  , Liu En-Ke  , Zhu Wei  , Feng Lin  , Wang Wen-Hong  , Wu Guang-Heng  ,   School of Science, Beijing University of Chemical Technology, Beijing 100029, China;,   State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

The structural and the magnetic properties of Co50Fe50-xSix alloys are investigated by carrying out experimental measurements and electron structure calculation. The alloy series exhibits the highly chemical ordering structure, showing a strong covalent bonding effect. The lattice parameters, molecular moment and Curie temperature linearly decrease with the increase of the Si content. The deviation of the structure is attributed to the atomic size effect. Based on Stearns theories, the decrease of the itinerant 3d (di) electron results in the decrease of Curie temperature due to the substitution of Si for Fe. The change of molecular moment follows the Slater-Pauling rule, but the calculation indicates that the change of the atomic moments is not linear. It implies that the covalent bonding effect is responsible for the magnetic changes. The molecular moment and Curie temperature of Heusler alloy Co2FeSi are measured to be 5.92 B and 777 ℃, respectively. The calculation results also indicate that the half-metallic property of Co2FeSi may not be so perfect as reported, which requires a new design of energy band for the practical application. The investigation also shows that the structural transition and the magnetic structure transition accumulate in a narrow interval of Si content, which may become a good object for studying the interaction between the magnetization and the structure.
Scaling law of quantum Hall plateau-to-plateau transition in single layer graphene
Authors: Tan Zhen-Bing  , Ma Li  , Liu Guang-Tong  , Lü Li  , Yang Chang-Li  ,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics,Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

Scaling law of quantum Hall plateau-to-plateau transition in single layer graphene is studied in a temperature range from 2 K to 50 K. We find that the scaling exponent is not universal. In a low temperature range, is about 0.13, while in a high temperature range, is about 0.33. The result indicates the dominance of long range scattering in graphene.
Power characteristics of SiC bipolar-mode JFET
Authors: Zhang Lin  , Yang Fei  , Xiao Jian  , Gu Wen-Ping  , Qiu Yan-Zhang  ,   School of Electronic and Control Engineering, Road Traffic Detection and Equipment Engineering Research Center, Chang'an University, Xi’an 710064, China;,   The National Key Laboratory of ASIC, The 13th Research Institute, CETC, Shijiazhuang 050051, China
Published: December 2020

The operational mechanism of normally-off type bipolar-mode SiC junction field effect transistor (BJFET) is studied by using a two-dimensional numerical model. Compared with the unipolar-mode SiC JFET, the bipolar-mode can reduce the on-state resistor of the SiC JFET effectively and compromise between the on-state and off-state characteristic of the device. The simulation resluts also show that switching time of BJFET increases remarkably.
Structure and electromagnetic transport properties of compound NdNi2Ge2
Authors: Yu Hong-Fei  , Zhang Lu-Shan  , Wu Xiao-Hui  , Guo Yong-Quan  ,   School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, China
Published: December 2020

The sample of compound NdNi2Ge2 is prepared by arc melting. The crystal structure is analyzed using powder X-ray diffraction and refined with Rietveld is method. It is shown that NdNi2Ge2 intermetallic compound crystallizes into a tetragonal structure with space group of I/4mmm and its lattice constant is a=4.120(1),c=9.835(0), Z=2. Nd atoms occupy 2a positions, Ni atoms 4d positions and Ge atom 4e positions. NdNi2Ge2 intermetallic compound has a Curie-Weiss constant of 25.8 and Curie-Weiss temperature of 6.24 K. The effective magnetic moment is 3.69B, which is very close to that of Nd3+. It implies that the magnetic moment originates mainly from Nd3+ ion. The resistivity varies from 0.3 m1.1 m. Fitting results show that this intermetallic compound is semimetal.