bluuebunny/crossref_metadata_2025 huggingface dataset:
Tunneling conductance spectrum of graphene ferromagnet-insulator-superconductor junctions
Authors: Chen Yu  , Chen Jia-Lin  , Zha Guo-Qiao  , Zhou Shi-Ping  ,   Department of physics, Shanghai University, Shanghai 200444, China
Published: December 2020

Starting with the mean field Dirac-Bogoliubov-de-Gennes model and the Bolonder-Tinkham-Klapwijk formalism, we study the transport properties of a graphene ferromagnet-insulator-superconductor junction by taking into account the effect of the finite width of the insulating region. The tunneling conductance oscillations as a function of the bias energy are revealed together with a non-monotonic behavior for the exchange field in the ferromagnet layer. These phenomena, which are quite different from those in the conventional counterparts, are understood by examining the electron scattering processes associated with the unique dispersion-relation of the graphene junctions.
The mechanism of electrical treeing propagation in polypropylene
Authors: Chi Xiao-Hong  , Gao Jun-Guo  , Zheng Jie  , Zhang Xiao-Hong  ,   Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China
Published: December 2020

Growth property of electrical treeing is an important parameter to evaluate the insulation performance of a polymer. The complex non-uniform state of aggregation structure determines the electrical treeing growth in polypropylene (PP), a typical semi-crystalline polymer. In this paper, the electric treeing resistance property experiments for PP as well as the PP sample with nucleating agents are carried out. Effects of crystal shape, crystallinity, and crystalline structure on the electrical treeing growth characteristics in PP and PP with nucleating agents have been analyzed using polarized light microscopy (PLM) and differential scanning calorimetry (DSC). Thermodynamic and dynamic mechanisms of electrical treeing propagation are represented respectively by the thermodynamically driven action of phase interfacial free energy and the discharge-avalanche theory, demonstrating the essential role of electric field distribution in electrical treeing growth. According to physical properties of crystalline phase and amorphous phase in semi-crystalline materials, a computational model of interior electric field distribution has been established to simulate local electric field distribution in the polymer material under needle-plate electrode configuration, and used to analyze the characteristics of electrical treeing channel growing along the grain boundary in semi-crystalline materials. Inhibition effects of crystalline structure changed due to the nucleating agents on electrical treeing growth along the electric field direction are investigated.
Study of the properties of strong-coupling magnetopolaron in quantum disks induced by the Rashba spin-orbit interaction
Authors: Bai Xu-Fang  , Wuyunqimuge  , Xin Wei  , Eerdunchaolu  ,   College of Physics and Electronic Information, Inner Mongolia University for Nationalities, Tongliao 028043, China;,   Department of Physics, Hebei Normal University of Science & Technology, Qinhuangdao 066004, China
Published: December 2020

On the basis of Lee-Low-Pines unitary transformation, the properties of strong-coupling magnetopolarons in quantum disks (QDs) induced by the Rashba spin-orbit interaction are studied using the Tokuda improved linearly combined operator method. Results show that the state properties of magnetopolarons are closely linked with the sign of the interaction energy Eint, and the Eint of magnetopolarons changes with the transverse confinement strength 0, the cyclotron frequency of the external magnetic field c, the electron-LO phonon coupling strength , and the thickness L of QDs. The average number N of phonons increases with increasing c, 0 and , but the oscillation decreases with increasing thickness L of QDs. The effective mass m0* of magnetopolarons splits into two (m+*, m-*), induced by the Rashba spin-orbit interaction, and the values of them increase with increasing c, 0 and , but the oscillation decreases with increasing thickness L of QDs. For the ground state of magnetopolarons in QDs, the electron-LO phonon interaction plays a significant role, meanwhile, the Rashba spin-orbit coupling effect cannot be ignored. Only for the lower volocity of the electrons, can the polaron effect and the Rashba spin-orbit interaction effect on the magnetopolaron be obvious.
Properties of memristor in RLC circuit and diode circuit
Authors: Wang Tian-Shu  , Zhang Rui-De  , Guan Zhe  , Ba Ke  , Zu Yun-Xiao  ,   School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

The study focuses on studying the basic properties of memristors in RLC circuit and diode circuit. Mathematical models are built up separately for memristors in the two types of circuits. In order to understand the influence of the model's parameters on the circuits' properties, simulations are made for the two mathematical models. The model's parameters include properties such as the capacitance, resistance and inductance. In the final part of the paper, we give and make conclusions based on the simulation results.
Design of a polarization-insensitive and broadband terahertz absorber using metamaterials
Authors: Zou Tao-Bo  , Hu Fang-Rong  , Xiao Jing  , Zhang Long-Hui  , Liu Fang  , Chen Tao  , Niu Jun-Hao  , Xiong Xian-Ming  ,   College of Electronic Engineering and automation, Guilin University of Electronic Technology, Guilin 541004, China;,   Air Force Services College, Xuzhou 221000, China
Published: December 2020

A polarization-insensitive and broadband terahertz (THz) absorber based on metamaterial (MM) is presented. The absorber consists of two layers of metal and a single layer of medium. Each periodic cell of the upper metallic layer consists of five different sizes of metal patches which form a square array of 55. In the array, the size of each metal patch is different from that of its adjacent one, and each size of the metal patch generates a single resonance absorption peak. The broadband absorption is actually produced by the overlapping of five adjacent resonance absorption peaks. By studying the distribution of the surface current and the z-component of electric field, it is easy to know that the energy of the incident THz wave is absorbed by two factors: one is the electric dipole oscillation caused by the electric field in the y direction, and the other is the magnetic polariton caused by the magnetic field in the z direction. And the ohmic loss of metal layers plays a major role on the absorption of the absorber. Simulation results show that the bandwidth achieves 1.2 THz for the absorption beyond 80%, and the maximum absorption is up to 98.7%. It's full width at half maximum (FWHM) is 1.6 THz, and the thickness of the broadband absorber is only about one twentieth of the center wavelength. In addition, the absorber is insensitive to the polarization and has a wide-angle feature, and the potential applications of the absorber are electromagnetic stealth, THz thermal radiation detectors, and THz communication.
Activity analysis of depression electroencephalogram based on modified power spectral entropy
Authors: Wang Kai-Ming  , Zhong Ning  , Zhou Hai-Yan  ,   International WIC Institute, Beijing University of Technology, Beijing 100124, China;,   Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing 100124, China;,   Beijing International Collaboration Base on Brain Informatics and Wisdom Services, Beijing 100124, China;,   Dept. of Life Science and Informatics, Maebashi Institute of Technology, Maebashi 371-0816, Japan
Published: December 2020

A method is proposed to calculate and analyze electro-encephalogram signal to improve the situation that there is an urgent need for an effective quantitative indicator to describe brain mental disorders. The method defines a spectral entropy in terms of the power spectrum division of time series. Then, the entropy is applied to numerical calculation of electroencephalogram signals of depression patients and normal control group. Meanwhile, the differences are compared between them. Experimental results show that the power spectral entropy in depression patients is significantly weaker than the normal healthy people's in some brain regions. Further analysis proves two facts. One is that the entropy is positively correlated to brain electrical physiological activity, and the other tells that the entropy can be used as a parameter to measure brain electrical activity, to characterize brain electrical physiological activities, and to provide the activity intensity information. This paper determines that the power spectral entropy for electroencephalogram plays an important role in diagnosis of brain mental disorder.
Research on three-junction bonding solar cell
Authors: Peng Hong-Ling  , Zhang Wei  , Sun Li-Jie  , Ma Shao-Dong  , Shi Yan  , Qu Hong-Wei  , Zhang Ye-Jin  , Zheng Wan-Hua  ,   State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;,   Shanghai Institute of Space Power Sources, CASC, Shanghai 200245, China
Published: December 2020

The multi-junction bonding GaInP/GaAs/InGaAsP solar cell was developed. Bonding technology can reduce dislocations and defects produced in the epitaxial growth process of the lattice mismatch materials, and the defects are restricted within dozens of nanometer layers at the interface without spreading into the inner layers. Bonding solar cell is one of the efficient developing trends in the future. The solar cell interface uses p+ GaAs/n+ InP tunneling junction, and the open circuit voltage is greater than 3.0V. The efficiency is 24% when the structural parameter is not optimized and the anti-reflective film is not prepared. Open circuit voltage shows that the two solar sub cells are connected in series. Results are analyzed and the improvement measures are given. This bonding technology provides a new way for monolithic integration high efficient multi-junction cells.
Simulation of pedestrian evacuation based on Jilin fire
Authors: Hou Lei  , Liu Jian-Guo  , Pan Xue  , Guo Qiang  , Wang Bing-Hong  ,   Research Center of Complex Systems Science, University of Shanghai for Science and Technology, Shanghai 200093, China
Published: December 2020

In the fire of the factory of Jilin poultry company occurred on 3 June, 2013, which was the biggest fire disaster in the recent 13 years, 120 people were burned. One of the most important reasons lies in the shut off of 3 out of 6 exits, and further, the staff did not know which exit can be used to evacuate. In this paper, we simulate the evacuation process of the fire of Jilin using the foor field model, and show the importance of each exit and the influence of the shut off of exits. Results show that, if only there had been one more exit opened when the fire occurred, about 54.3% of the burned pedestrians could survive, and if all the exits ware opened, 76.6% of the burned pedestrians would survive. In addition, if the pedestrians had got the information of the availability of each exit, the number of burned pedestrians would reduce 21.6%. Hence, it is crucial to maintain the availability of the exits and spread the availability information for preventing loss of life and property.
Analysis of tracking error of telescope based on AR-search-iteration algorithm
Authors: Liao Hong-Yu  , Ma Xiao-Yu  , Guo You-Ming  , Rao Chang-Hui  , Wei Kai  ,   Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610029, China;,   Key Lab of Adaptive Optics, Chinese Academy of Sciences, Chengdu 610029, China;,   Graduate School, Chinese Academy of Sciences, Beijing 100039, China
Published: December 2020

The tracking errors of large-caliber optical telescope in the process of observing astral target consists of telescope tracking jitter error which is mainly caused by wind-load, and wave-front tilt error caused by atmospheric turbulence. A simplified model concerning telescope tracking error is established, and a new kind of algorithm based on AR model to separate the telescope tracking jitter error from the tracking error caused by atmospheric turbulence is proposed. Finally, an experiment is conducted on the platform of the 1.8 M telescope in Gaomeigu Observing Station to test this algorithm. Experimental results show that the telescope tracking jitter error caused by wind-load is directly related to the direction and speed of the wind, which conforms to the theoretical analysis.
Improved complex variable element-free Galerkin method for viscoelasticity problems
Authors: Peng Miao-Juan  , Liu Qian  ,   Department of Civil Engineering, Shanghai University, Shanghai 200072, China
Published: December 2020

In this paper, based on the improved complex variable least-square (ICVMLS) approximation, the improved complex variable element-free Galerkin (ICVEFG) method for two-dimensional viscoelasticity problems is proposed. The ICVMLS approximation is used to form the shape function, the Galerkin weak form is used to obtain the system equations, and the penalty method is used to impose the essential boundary conditions, then the corresponding formulae of the ICVEFG method for two-dimensional viscoelasticity problems are obtained. Finally, some numerical examples are given, and the numerical results from the ICVEFG method are compared with those from the CVEFG method and finite element method, and the results show that the ICVEFG method in this paper has the high computational precision and efficiency.
Periodic wave and solitary wave of curved face in barotropic atmospheric circulation
Authors: Mao Jie-Jian  , Wu Bo  , Fu Min  , Huang Ying  , Yang Jian-Rong  , Ren Bo  , Liu Ping  ,   Department of Physics and Electronics, Shangrao Normal University, Shangrao 334001, China;,   Institute of Nonlinear Science, Shaoxing University, Shaoxing 312000, China;,   College of Electron and Information Engineering, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China
Published: December 2020

The wave motion characteristic of large-scale barotropic atmospheric circulation, which can be described by the original nonlinear shallow water equations, is important for comprehending the climatic change. Employing the complex solution of linear equation, and transplanting it twice, the new analytic solution of disturbed height field of the nonlinear evolution equation is obtained which is constructed by the basic flow term and fluctuation term. The basic flow is codetermined by the wave number, wave velocity, β effect, radius of deformation and arbitrary function of time. The fluctuation term is related to β effect, and displays that in the disturbed height field there exist the periodic wave and solitary wave of curved face, which modulate each other and present instability; several periodic-solitary waves can propagate independently when they appear simultaneously; the arbitrary function of time in the fluctuation term has a modulation effect on the amplitude of periodic-solitary wave, and can control the occurrence, development and vanishing of wave. The results have a certain theoretical reference value for studying the atmospheric fluctuation phenomena and climatic change.
Design and simulation of a memristor chaotic circuit based on current feedback op amp
Authors: Hong Qing-Hui  , Li Zhi-Jun  , Zeng Jin-Fang  , Zeng Yi-Cheng  ,   Department of Photoelectric Engineering, Xiangtan University, Xiangtan 411105, China;,   College of Information Engineering, Xiangtan University, Xiangtan 411105, China
Published: December 2020

In this work, we propose a novel memristor chaotic circuit, which combines current feedback op amp with four basic electronic components, such as capacitance, inductance, resistance and memristor. The dynamic properties of the new circuit are demonstrated, such as system dissipation, equilibrium stability, phase portrait, Lyapunov exponent spectrum, and parameter influence. Numerical simulation results show that the circuit produces a kind of special chaotic attractor and exhibits complicated chaotic behaviour with the evolution of the system parameters. In order to confirm the correctness of the system, a realizing circuit is designed, Pspice simulation results verify the correctness of theoretical analysis.
Design and implementation of grid multi-scroll chaotic circuit based on current feedback operational amplifier
Authors: Wu Xian-Ming  , He Yi-Gang  , Yu Wen-Xin  ,   College of Electrical and Information Engineering, Hunan University, Changsha 410082, China;,   School of Electrical and Automation Engineering, Hefei University of Technology, Hefei 230009, China
Published: December 2020

In this paper, a method is proposed to realize the grid multi-scroll chaotic system with the current feedback operational amplifier (CFOA). Firstly, nonlinear circuit is designed based on the CFOA. Then the grid multi-scroll chaotic circuit is designed and relevant circuit parameters are calculated. Finally circuit simulation is conducted, and the results show that the circuit has a higher central frequency, needs less components, and possesses simpler circuit structure, good frequency characteristic and port characteristic of the CFOA.
Efficiency calibration for a NaI scintillation detector based on Monte-Carlo process and preliminary measurements of bremsstrahlung
Authors: Huang Jian-Wei  , Wang Nai-Yan  ,   College of Nuclear Science and Technology Beijing Normal University, Beijing 100875, China;,   China Institute of Atomic Energy, Beijing 102413, China;,   The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University, Beijing 100875, China;,   Beijing Radiation Center, Beijing 100875, China
Published: December 2020

In order to better apply the NaI scintillation spectrometer to bremsstrahlung measurements, the energy response function of a NaI detector spectrometer system is studied by using 137Cs and 60Co sources based on Monte Carlo N particle transport code (MCNP) process. Simulated and measured almighty peak efficiency are in good agreement. An energy response matrix (ERM) is obtained by simulating photons with a certain energy incident on the NaI crystal in MCNP process, through deconvoluting the detected spectrum of NaI using the ERM, and the results of the deconvolution accord well with those from the original spectrum. Furthermore, the NaI detector is used to preliminarily detect its response to bremsstrahlung generated by high intensity electrons bombarding a target of 1.5 mm thickness.
Comparison of two approaches to magnetic field quantification by polarized neutron images
Authors: Cao Chao  , Wang Sheng  , Tang Ke  , Yin Wei  , Wu Yang  ,   Insitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Polarized neutron radiography allows the direct and real-space visualization of magnetic field distribution by detecting the polarization change in the transmitted beam. Two approaches to magnetic field quantification by means of polarized neutron images are studied. They are energy-selective method and spin-echo method. Both approaches need no corrections of parameters, such as polarization efficiency, and can quantify magnetic field integral without periodic uncertainty. The quantification ability, applicability and feasibility of two approaches at research reactor neutron source are verified by numerical simulation with key parameters such as monochromator resolution and polarization efficiency. The results will be helpful to process image data and designing instruments.
Design and preparation of a low frequency absorber based on hollowed-out cross-shaped meta-material structure
Authors: Zhou Zhuo-Hui  , Liu Xiao-Lai  , Huang Da-Qing  , Kang Fei-Yu  ,   College of Science, Beijing University of Chemical Technology, Beijing 100029, China;,   Beijing Institute of Aeronautical Materials, Beijing 100095, China;,   Materials Science and Engineering Department, Tsinghua University, Beijing 100083, China
Published: December 2020

A hollowed-out cross-shaped meta-material structure is designed and fabricated in this work. A kind of conventional magnetic material which works at low frequency is used as the absorber substrate. The simulation results demonstrate that an absorber can reach an absorption of less than -10 dB in a range between 2 GHz and 4 GHz, and the absorption band is expanded by a 0.5 GHz when the meta-material structure is unloaded. The experimental results indicate that a similar absorption band appears between 2.5 GHz and 5.1 GHz, which is 0.48 GHz wider than meta-material structure and the absorption band is expanded by 23% when the depth of absorption band below -9 dB. Compared with the cross meta-material, the hollowed-out structure has ability to increase the magnetic energy loss and strengthen the coupling between the units. The influence of magnetic layer thickness on absorption capability of wave absorber is analyzed. The result indicates that the position of addition absorption band does not apparently move with variation in thickness of the magnetic material layer. Based on these results, two different meta-material structures are combined to obtain a wider absorber. The simulation result and the experimental result both show another 0.9 GHz expansion of the absorption band and it can also reduce the thickness of the magnetic layer.
An optimal layered inhomogeneous background used in microwave tomography system in metallic chamber
Authors: Ding Liang  , Liu Pei-Guo  , He Jian-Guo  , Joe LoVetri  ,   School of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073, China;,   Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada
Published: December 2020

An optimal layered inhomogeneous background which can be used in an embedded microwave tomography system is proposed. The method is based on a new evaluation method of integral radiation operator with respect to an configuration and optimal methods such as simulated annealing method. First, the integral radiation operator is calculated using the finite element method. Then, a kind of metric which can be used to evaluate the operator is proposed. The metric contains information about the whole singular value spectrum of a integral radiation operator. A set of synthetic researches is performed to show the correlation between the metric and inversion error. The method can evaluate an integral radiation operator using a number, and it can be used in optimal process easily as the cost function. Simulated annealing method is employed to obtain the permittivity of each layer in the optimal layered inhomogeneous background. Finally, synthetic researches are employed both on simple target and complex target to test the optimal layered inhomogeneous background. The results show that the optimal layered inhomogeneous background can expedite the convergence process and more accurate inversion results can be obtained.
Infrared and visible image fusion based on deep Boltzmann model
Authors: Feng Xin  , Li Chuan  , Hu Kai-Qun  ,   College of Mechanical Engineering, Key Laboratory of Manufacturing Equipment Mechanism Design and Control of Chongqing, Chongqing Technology and Business University, Chongqing 400067, China
Published: December 2020

In the infrared and visible light image fusion, the noise interference always exists. There is also the disadvantage that image fusion is easy to produce artifacts which cause blurred edge and low contrast. In order to solve these problems, in this study we propose an image fusion method based on deep model segmentation. First of all, deep Bolzmann machine is adopted to learn prior target and background contour and construct a contour deep segmentation model. After the optimal energy segmentation, Split Bregman iteration is used to obtain the infrared and visible image contour. Then non-subsampled contourlet transform is adopted to decompose the source images. The segmented background contour coefficients are fused by the structure similarity rule. Finally, the fused image is reconstructed by the non-subsampled contourlet inverse transform. The experimental results show that this algorithm can effectively obtain fused images with clear target contour and background contour. The fused images also have high contrast and low noise. The results show that it is an effective method of achieving the infrared and visible image fusion.
Fabrication of pixelated polarizer array and its application in polarization enhancement
Authors: Zhang Zhi-Gang  , Dong Feng-Liang  , Zhang Qing-Chuan  , Chu Wei-Guo  , Qiu Kang  , Cheng Teng  , Gao Jie  , Wu Xiao-Ping  ,   CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China;,   Nanofabrication Laboratory, National Center for Nanoscience and Technology, Beijing 100190, China
Published: December 2020

Pixelated polarizer array can be used in the real-time measurement of Stokes parameters. In this paper, pixelated polarizer array based on the aluminum nano-grating is designed and fabricated, and the fabrication technology is electron beam exposure technology. The size of each unit is 7.4 μm, and the polarization directions of each adjacent 2×2 units in the polarizer array are 0, π/4, π/2, and 3π/4. The period, duty cycle, depth and surface type of the grating are 140 nm, 0.5, 100 nm and rectangle type, respectively. The scanning electron micrographs of the pixelated polarizer array show that there is no disconnection, cross and pollution on the fabricated metal nano-grating lines. The nano-grating lines are straight and uniform in thickness, and the surface type of the grating is ideal rectangular type. The polarization optical micrographs show that the pixelated polarizer array has good polarization characteristics. The maximum polarization transmissivity can reach 79.3%, and the extinction ratio can arrive at 454. Furthermore, the pixelated polarizer array is integrated with the charge coupled devise chip, and the Stokes parameters can be calculated from one frame, then the degree of linear polarization and angle of linear polarization can be obtained. Thus, the polarization enhancement of image is achieved, which can be used in the anti-stealth and recognition.
Effect of laser coherent superposition in multi-pass amplification process
Authors: Zhang Ying  , Liu Lan-Qin  , Wang Wen-Yi  , Huang Wan-Qing  , Geng Yuan-Chao  , Xie Xu-Dong  , Zhu Qi-Hua  ,   Research Center of Laser Fusion, CAEP, Mianyang 621900, China
Published: December 2020

Aming at the coherent superposition of laser pulse reflected from the cavity mirror in multi-pass amplification process, a physical model for describing the amplification of coherent superstition of the rising part and the falling part of the pulse in a gain medium is established. According to theoretical analysis, standing wave is formed by the coherent superposition of the rising part and falling part of the pulse. The inversion population density shows up the effect of hole-burning by the standing wave, and the gain and pulse shape are affected. Based on this physical model, three conditions, i.e., no superposition, coherent superposition, and incoherent superposition are compared. This study will provide the instructions for high power solid laser design.
Theoretical investigation of spatial optical solitons in nematic liquid crystals with negative dielectric anisotropy
Authors: Li Yi-Heng  , Wang Jing  , Hu Wei  , Guo Qi  ,   Laboratory of Nanophotonic Functional Materials and Devices, South China Normal University, Guangzhou 510006, China
Published: December 2020

In this paper, the nonlocal nonlinear medium, nematic liquid crystals (NLCs) with negative dielectric anisotropy, are studied. Theoretical research shows that NLCs with negative dielectric anisotropic have a negative nonlinear coefficient. The analytical expressions for characteristic length of the nonlocal response function and for nonlinear coefficient are given. Secondly, the solutions for spatial optical solitons in NLCs with negative dielectric anisotropic are obtained by numerical computation. Finally, the influences of beam power and bias voltage on the propagation of the beam in NLCs with negative dielectric anisotropic are investigated. The result shows that the critical power of the nonlocal spatial solitons in NLCs with negative dielectric anisotropic varies with bias voltage.
Dynamic behavior of rising bubble
Authors: Li Shuai  , Sun Long-Quan  , Zhang A-Man  ,   School of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China
Published: December 2020

This study focuses on the dynamic behavior of rising bubble in water with taking surface tension and viscous effect into consideration. The Young-Laplace equation is adopted to obtain the viscous component of the normal stress, and the tangential component is evaluated by viscous correction pressure, which is based on viscous dissipation energy equivalence principle. Firstly, both axi-symmetric and three-dimensional model is established by employing boundary integral method. The validation of our model is confirmed by comparing the analytical results with the experimental results, and they are in good agreement with each other. Secondly, the shape and balanced velocity of millimetre-sized bubble are studied, and the influences of initial condition, surface tension and viscosity on the dynamic behaviour of the bubble are also discussed. Finally a numerical technic is put forward to handle the coalescence of two rising bubbles, which can show some detailed information about the coalescence process.
Analysis on the azimuthal velocity fluctuation of drift-wave turbulence and zonal flow via dynamic programming based time-delay estimation technique in a linear magnetized plasma device
Authors: Chen Ran  , Liu A-Di  , Shao Lin-Ming  , Hu Guang-Hai  , Jin Xiao-Li  ,   CAS Key Laboratory of Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China;,   Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
Published: December 2020

The effective measurement of plasma turbulence flow field is of great help for better understanding the turbulence in magnetically confined plasmas, and experimentally verifying the theoretically predicted phenomenon such as zonal flows. In this article, the dynamic programming based time-delay estimation technique is employed for the first time to estimate azimuthal velocity fluctuation of drift-wave turbulence in a linear magnetized plasma generated via a hot cathode plasma source. Analysis results clearly reproduce the zonal flow structure which is spontaneously generated by nonlinear energy transfer from the drift-wave turbulence. Moreover, via the comparison among the zonal flow (ZF) characteristics estimated respectively by the turbulent fluctuations of plasma located in different frequency regions, we further evaluate the dependences of accuracy and response for estimating ZF property using this newly developed time-delay estimation algorithm on the level of relative incoherent noise in the carrier waves. This work provides an example and reference value for deeper exploration on plasma turbulence and in particular the relevant flow field with the help of the dynamic programming based time-delay estimation technique.
Physical investigation of dynamic process of the gas-puff Z-pinch through particle-in-cell simulation
Authors: Feng Zhi-Xing  , Ning Cheng  , Xue Chuang  , Li Bai-Wen  ,   Beijing Graduate School of China Academy of Engineering Physics, Beijing 100088, China;,   Beijing Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

In this paper the physical model and numerical algorithm of particle-in-cell (PIC) simulation for gas-puff Z-pinch in two-dimensional cylindrical coordinates are briefly introduced. The code is also developed according to the model and algorithm. The rarefied gas-puff Z-pinch driven by a low current is simulated through the code, and some reasonable results are obtained. The results include the spatiotemporal distributions of current, electromagnetic field, particle positions and density, as well as the trailing mass and current. It is found that the simulated current reflects the plasma Z-pinch characteristics, i.e., the plasma current arrives at a minimum when the plasma enters into stagnation, and it begins to increase after the plasma has moved outwards. The simulated magnetic field agrees well with the theoretic value. The electric field force and magnetic field force experienced by electron are almost the same in magnitude, while the force acting on ion is mainly the electric field force. Firstly the electron is accelerated in the z direction and reaches a velocity, then it moves inward the axis in the same time by the Lorentz force. That causes the separation between electron and ion, and a strong electric field is produced. The produced electric field attracts the ion inward the electron. When the electrons arrive at the axis, they move inversely due to the static repellency among them, while the ions continue to move initially inwards, and later enter into stagnation, and finally collapse. The trailing mass is about 20% of the total Z-pinch plasma, and the maximum trailing current is about 7% of the driven current. In the future the code needs to develop further and realize parallel computation in order to simulate the practical Z-pinch processes by PIC simulation.
Effects of preparation temperature of SiC intermediate layers on the hemocompatibility of SiC/F-DLC composite film
Authors: She Qing  , Jiang Mei-Fu  , Qian Nong  , Pan Yue  ,   School of Physical Science and Technology, Suzhou University, Suzhou 215006, China
Published: December 2020

A series of SiC intermediate layers with different preparation temperatures is prepared by radio frequency magnetron sputtering on 316L stainless steel substrates by use of SiC crystal target and Argon as source gases. And then depositing fluorinated diamond-like carbon films (F-DLC) on a series of SiC intermediate layers under the same deposition condition with trifluromethane (CHF3) and Argon as source gases, and pure graphite as a target, a series of SiC/F-DLC composite films are obtained. The results show that the composite films have stronger adhesion and better hemocompatibility than that of the F-DLC films. The structure evolves with preparation temperatures of SiC intermediate layers and SiC/F-DLC composite films are studied by their Raman and Infrared transmission spectra. The results show that the proportion of C=C bonds and density of C-C unsaturated bonds in the SiC intermediate layers can be modulated by controlling the preparation temperature of SiC intermediate layers. The composite films have better hemocompatibility, especially with about 500 ℃ preparation temperature, may be attributed to holding higher proportion of aromatic ring structure and higher ratio of F/C in the composite films than the others. Formation of a considerable number of Si-C bonds and C=C bonds between SiC and F-DLC films may be the direct cause of strong adhesion. The addition of modest SiC intermediate layers between 316L stainless steel substrates and F-DLC films is feasible and effective to enhance films adhesion and improve film hemocompatibility.
First-principles study of the structural, elastic and electronic properties of RhB under high pressure
Authors: Wang Jin-Rong  , Zhu Jun  , Hao Yan-Jun  , Ji Guang-Fu  , Xiang Gang  , Zou Yang-Chun  ,   College of Physical Science and Technology, Sichuan University, Chengdu 610064, China;,   Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The structural phase transition, elastic, electronic properties and hardness for boride rhodium (RhB) under high pressure are systematically investigated by using the pseudopotential plane-wave density functional. The obtained lattice parameters, bulk modulus and elasitc constants are in good agreement with the available experimental and previous theoretical results at zero pressure. Furthermore, the mechanism of the high pressure structural phase transition is studied in detail. Our results show that RhB undergoes a structural phase transition from anti-NiAs-type to FeB-type at 25.3 GPa, which is in good agreement with other reported theoretical result. We also predict the pressure induced elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's coefficients, and elastic anisotropy factors, and find that the pressure has an important influence on the elastic properties. The calculated electronic density of states reveals that the pressure will strengthen the orbital hybridization between the Rh states and B states, the nonlocal effect and the strength of the covalent bond. Finally, on the basis of the Mulliken overlap populationanalysis, we obtain that the hardness of anti-NiAs-RhB is 18.1 GPa, which is compatible to the experimental value.
Observation of s-d exchange interaction within Cd0.96Zn0.04S/Cd0.97Mn0.03S/Cd0.96Zn0.04S multilayer nanowires
Authors: Chen Pei-Geng  , Lu Jia-Dao  , Guo Wen-An  , Li Yong-Liang  , Gao You-Hui  ,   Department of Physics, Beijing Normal University, Beijing 100875, China;,   Analysis and Testing Center, Beijing Normal University, Beijing 100875, China
Published: December 2020

Transport properties of Cd0.96Zn0.04S/Cd0.97Mn0.03S/Cd0.96Zn0.04S multilayer nanowires, deposited in porous anodic aluminum oxide templates by DC electrochemical method, are studied. It is found that the transmission current oscillates against the applied magnetic field, even the thickness of the spin doping barrier is about 96 nm. s-d exchange constant N0 is obtained from the resonant transmission measurement. A e-(1/T) temperature dependence of N0α ndicates the electrostatic interaction nature of the s-d exchange interaction.
Effect of irradiation damage on the dark electric properties of single junction GaAs/Ge solar cells
Authors: Yue Long  , Wu Yi-Yong  , Zhang Yan-Qing  , Hu Jian-Min  , Sun Cheng-Yue  , Hao Ming-Ming  , Lan Mu-Jie  ,   School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;,   The Fifth Electronics Research Institute of Ministry of Industry and Information Technology, Science and Technology on Realiability Physics and Application of Electronic Component Laboratory, Guangzhou 510610, China;,   Harbin Normal University, School of Physics and Electronic Engineering, Harbin 150025, China;,   Harbin Institute of Technology, School of Astronautics, Harbin 150025, China
Published: December 2020

In this paper, the dark electrical properties are studied by measuring the dark current-voltage characteristics of a type of domestic single-junction (SJ) GaAs/Ge solar cell after proton irradiation. Using a double exponential mode for the dark electrical properties of p-n junction, the dark I-V curves of the proton-irradiated SJ cells are mathematically fitted, and there are four kinds of typical parameters, namely serious resistance (Rs), parallel resistance (Rsh), diffusion current (Is1), and recombination current (Is2), which are determined to characterize the irradiation effects. Hence, four parameters such as Rs, Rsh, Is1 and Is2 are significantly changed after proton irradiation, where Rs, Rsh, Is1 increase while Rsh decreases with increasing the displacement damage dose. In addition, R_{s } increases with displacement damage dose, which is unrelated to proton energies. Theoretical analysis indicates that the above-mentioned changes of the parameters result from the damage distributions in different regions of the solar cells. Irradiation-induced damage in the base and emitter regions of the cells could induce Rs and Is1 to augment, while junction-region damage causes the Rsh to decrease but the Is2 to increase.
Complementary metal-oxide-semiconductor humidity sensor design for passive ultra-high frequency radio-frequency identification application
Authors: Deng Fang-Ming  , He Yi-Gang  , Zuo Lei  , Li Bing  , Wu Ke-Han  ,   School of Electrical Engineering and Automation, Hefei University of Technology, Hefei 290009, China;,   School of Electrical and Electronic Engineering, East China JiaoTong University, Nanchang 330013, China
Published: December 2020

This paper presents a low-cost low-power humidity sensor for applications of ultra-high frequency radio frequency identification sensing tag. The humidity sensor element, based on standard SMIC 0.35 μm complementary metal-oxide-semiconductor technology, utilizes polyimide as sensing material and fabricates the interdigitated electrodes in top metal layer without any further post-processing. The humidity sensor interface, based on phase-locked loop theory, employs fully-digital architecture and achieves direct capacitance-to-digital conversion, which allows the supply voltage to be close to threshold voltage. The measurements at 25 ℃ show that the proposed humidity sensor achieves a sensitivity of 36.5 fF%RH, maximum hysteresis error of 7%, response time of 20 ms, and 2.1 μW power dissipation at 0.6 V supply voltage.
Spatially adapted total variation model with nonconvex regularizer based speckle reduction
Authors: Li Jin-Cai  , Peng Yu-Xing  , Zhu Min  , Chen Peng  ,   School of Computer Science, National University of Defense Technology, Changsha 410073, China;,   Department of Information Engineering, Zhoukou Vocational and Technical College, Zhoukou 466000, China
Published: December 2020

Total variation is a hot point of research on speckle reduction. The nonconvex regularizer can better preserve or even enhance the information about the edges of an image. Spatially adaptive regularization parameters can reasonably control the level of speckle reduction according to the region in which the pixels are, and improve the speckle reduction effect. In this paper, we present a new total variation model for speckle reduction by integrating nonconvex regularizer and spatially adaptive regularization parameters. In order to solve the model, a new algorithm is designed based on Newton's method, augmented Lagrange multiplier, alternating direction method of multipliers, and iteratively reweighted method. The numerical examples demonstrate that the proposed model can obtain the better speckle reduction effect.
Interlacing layered complex networks
Authors: Shen Di  , Li Jian-Hua  , Zhang Qiang  , Zhu Rui  ,   School of Information and Navigation, Air Force Engineering University, Xi'an 710077, China;,   PLA 93801 Troop, Xianyang 712200, China
Published: December 2020

In order to study the structural characteristic and node centrality of a structure composed of two related heterogeneous networks, in this paper, interlacing layered complex networks are defined as networks which are composed of two subnets having the partially same nodes and similar links. Also the definitions of the node interlacing coefficient, path interlacing coefficient and networks interlacing coefficient are given, so the intimacy level of two subnets can be measured definitely. Based on the definitions above, a node centrality algorithm of degree and betweenness is studied and redefined, while a new node centrality measuring index is given, which can be used to measure the supporting degree of a node in one subnet to the others' connectivity and negotiability. Finally, experimental results show that the proposed method is effective.
Discussion on the application of entransy theory to heat-work conversion processes
Authors: Cheng Xue-Tao  , Liang Xin-Gang  ,   Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
Published: December 2020

Applications and limitations of the entransy theory for heat-work conversion processes are analyzed and discussed in this paper. Our analyses for the Carnot cycle show that the system entransy of the Carnot cycle is in balance, but the relationship, dG=T2dS, does not exsit between the concepts of entransy and entropy. Therefore, the concept of entropy cannot be replaced by the concept of entransy. For common thermodynamic processes, the analyses show that the present entransy theory is applicable when heat is transferred into an endoreversible thermodynamic cycle to do work. In addition, in the analyses of heat-work conversion processes, the differences between the entransy theory and entropy theory are also discussed. It is shown that the viewpoints and preconditions of the two theories for the analyses and optimizations of heat-work conversion processes are different. The viewpoint of the analyses of entropy generation is the loss of exergy, while that of the analyses of entransy is the consumption of thermal potential. When the input exergy flow of the discussed system is prescribed or the input heat flow and the corresponding thermodynamic forces of the heat flows into and out of the system are prescribed, the entropy generation minimization leads to the maximum output work. For the entransy theory, the maximum entransy loss corresponds to the maximum output work when the input heat flow and the corresponding temperatures of the heat flows into and out of the system are prescribed. Meanwhile, they both have limitations. When the corresponding preconditions are not satisfied, the maximum entransy loss or the minimum entropy generation may not correspond to the maximum output work.
Noise-induced intermittency in Hénon map and estimation of critical strength of noise
Authors: Guo Kong-Ming  , Jiang Jun  ,   School of Electromechanical Engineering, Xidian University, Xi'an 710071, China;,   State Key Laboratory for Strength and Vibration, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

In this paper noise-induced intermittency phenomenon in Hénon map is studied. Through numerical simulation and global analysis the mechanism of noise-induced intermittency in Hénon map is revealed. By using stochastic sensitivity function method to detect whether there will be collisions between confidence ellipse of periodic attractor and chaotic saddle, a method to estimate the critical strength of noise is proposed. Results show that the noise-induced intermittency in Hénon map is caused by interactions between cycle attractor and unstable manifold of chaotic saddle, whereas the stochastic sensitivity function method can estimate the critical noise strength in intermittency phenomenon accurately.
Fluctuation effects of thermodynamic variables in particle-spilling-from-well model with single potential well
Authors: Zhang Xue-Jun  , Rao Jian  , Deng Yang-Bao  , Jiang Lian-jun  , Tian Ye  ,   School of Communication and Electronic Engineering, Hunan City University, Yiyang 413000, China
Published: December 2020

Under ergodic condition, the analytic expressions for the fluctuations of temperature and particle number in the well of a system are obtained rigorously in particle-spilling-from-well model by means of integration approaches in phase space; the relationships among fluctuations of thermodynamic variables, the total particle numbers, and the well volume are emphasized. Results show that the less the total number of particles and the smaller the well's volume, the more remarkable the thermodynamic fluctuations effect, and the more closely the thermodynamic fluctuations related to the particle spilling from the well. There is a one to one correspondence between particle spilling from the well and the occurrence of negative specific heat, and the huge thermodynamic fluctuations,as well as, the origin of this phenomenon can be understood by the apparent energy inverse partition.