bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental research of tip/tilt control of a multi-channel fiber-laser array
Authors: Geng Chao  , Tan Yi  , Mu Jin-Bo  , Li Xin-Yang  ,   The Laboratory on Adaptive Optics, Institute of Optics and Electronics, Chinese Academy of Sciences, the Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu 610209, China
Published: December 2020

The fiber-laser array technique has an extensive prospect of applications in the areas of coherent beam combination, free-space laser communications and so on. In this paper, considering the development trend of the fiber-laser array technique, the research progress of an adaptive fiber-optic collimator based on large-mode-area fiber is introduced, a 7-channel fiber-laser array is established, the tip/tilt control experiment of laser array under parallel-transmission configuration is conducted, and the tip/tilt control of laser array under conformal-transmission configuration using target-in-the-loop is explored. Finally, the tip/tilt control and phase locking of two 10-W level fiber lasers are achieved in the master-oscillator-power-amplifier (MOPA) system with three-stage all-fiber amplifiers. This paper presents a reference for using the fiber-laser array technique in real atmospheric environment.
Energy dissipation of a granular system under vertical vibration
Authors: Peng Zheng  , Jiang Yi-Min  , Liu Rui  , Hou Mei-Ying  ,   School of Physics and Electronics, Central South University, Changsha 410083, China;,   Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

For a vertically vibrating box filled with Cu grains or glass beads, we study power of dissipating energy of the granular system, by measuring acceleration of the box and force acting on it. It is found that for a given vibrating strength the power displays a wide peak structure centered at several tens Hz as vibrating frequency varies, and for a given frequency its variation with the strength obeys a power law, with an exponent smaller than that of a forced harmonic oscillator model 2. The results are considered to be useful for determining magnitudes of transport coefficients of granular liquids and gases, as well as difference in dissipative energy between their different dynamic patterns.
Influence of gas flow on the size and crystal of silicon nanoparticle produced by laser deposition in low pressure
Authors: Wang Ying-Long  , Gao Jian-Cong  , Chu Li-Zhi  , Deng Ze-Chao  , Ding Xue-Cheng  , Liang Wei-Hua  , Fu Guang-Sheng  ,   College of Physics Science and Technology, Hebei Key Laboratory of Optic-electronic Information & Materials, Hebei University, Baoding, Hebei 071002, China
Published: December 2020

The nanocrystal silicon films were prepared by using a pulsed laser to ablate a high-resistivity single crystalline Si target in an ambient pressure range of 0.01-0.5 Pa of pure argon gas. An argon gas flow is introduced in the horizontal direction of the ablation point in an axial range of 2 cm. Nanocrystal Si films are deposited on glass or single crystalline (111) Si substrates placed at a distance of 1 cm below the nozzle. Then the same device is used to prepare the ranocrystal Si films at a pressure of 0.08 Pa with gas flow being, respectively, 0, 2.5, 5, 7.5, 10 sccm. The morphologies and microstructurs of the samples are characterized by atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman scattering. The results show that the Si nanocrystal threshold pressure is 0.1 Pa without gasflow, and 0.05 Pa with gasflow. The size of Si nanocrystal decreases as the gasflow increases.
Numerical study of double tearing mode instability in viscous plasma
Authors: Zheng Shu  , Zhang Jia-Peng  , Duan Ping  , Wei Lai  , Wang Xian-Qu  ,   School of Physics and Optoelectronic technology, Dalian University of Technology, Dalian 116024, China;,   Department of Physics, Dalian Maritime University, Dalian 116026, China
Published: December 2020

The scalings of double tearing mode (DTM) with various values of resistivity and viscosity have been investigated numerically by using a magneto hydrodynamic model in slab geometry. It is found that the growth rate changes from γ∝η3/5ν0 to γ∝η5/6ν-1/6 when the distance between two rational surfaces 2xs is sufficiently large. On the other hand, when the distance between two rational surfaces 2xs is very small, the scaling of γ and η and ν changes from γ∝η1/3ν0 to γ∝η2/3ν-1/3 as the viscosity increases. Moreover, the nonlinear evolution of symmetrical DTM is investigated in this paper. The study shows that the symmetrical DTM transforms to unsymmetrical DTM in the final phase.
AC properties of Pr0.7Ca0.3MnO3 ceramics
Authors: Shi Da-Wei  , Wu Mei-Ling  , Yang Chang-Ping  , Ren Chun-Ling  , Xiao Hai-Bo  , Wang Kai-Ying  ,   Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 China;,   Department of Micro and Nano Systems Technology, Vestfold University College - HiVe, Horten 3184, Norway
Published: December 2020

Ceramic Pr1-xCaxMnO3(x=0.3) samples are prepared by solid-state reaction and measured using direct current (DC) and alternating current (AC) methods in different magnetic and electrical fields. A Curie temperature of 150 K is determined by I-V measurements in field for Pr0.7Ca0.3MnO3, which is consistent with that from vibrating sample magnetometer (VSM). The AC measurement shows that the grain boundary resistance reduces with magnetic field increasing, while the grain almost keeps unchanged, and it indicates that the colossal magnetoresistance (CMR) effect in low field mainly comes from the grain boundary for the Pr0.7Ca0.3MnO3 ceramic. The barrier height of grain boundary is 117 meV for the Pr0.7Ca0.3MnO3 ceramic, obtained by fitting the temperature spectrum of impedance, and it is well coincident with that from fitting the R-T data. A trap state model is proposed to explain all the measured data.
Modulational instabilities of two-component Bose-Einstein condensates in the optical lattices
Authors: Teng Fei  , Xie Zheng-Wei  ,   College of Physics and Electtonic Engineering, Sichuan Normal Univercity, Chengdu 610066, China
Published: December 2020

Based on the linear stability analysis, the modulational instablilities (MIs) of two-component Bose-Einstein condensations (BECs) in the optical lattices are studied, especially the relation of MI with the different component and modulational wavevectors, and with the inter- and intra- interaction when the condition of atom current conversation is not satisfied. The results show that when the condition of atom current is not satisfied, the new MI areas of two-component BEC in the optical lattice with the component wavevectors, modulational wavevectors and the interaction between components can arise. The above results can gives us some useful information about manipulating two-component BECs in practice.
Mn-doping effects on structural, optical and magnetic properties of BaSn1-xMnxO3
Authors: Zhang Peng  , Liu Qin-Zhuang  , Su Fu-Hai  , Liu Qiang-Chun  , Liu Zhe  , Song Wen-Hai  , Dai Jian-Ming  ,   School of Physics and Electronic Information,Huaibei Normal University,Huaibei 235000, China;,   Key Laboratory of Materials Physics,Institute of Solid State Physics,CA Sciences,Hefei 230031, China
Published: December 2020

Polycrystalline bulk samples of BaSn1-xMnxO3 with x=0, 0.05, 0.10 and 0.13 are prepared by the conventional solid state reaction method. The effects of Mn concentration on crystal structural, optical and magnetic properties of BaSn1-xMnxO3 are investigated systematically. Powder X-ray diffraction (XRD) shows that each of these compounds presens a perovskite structure (with the space group Pm3m) without the secondary crystalline phase. The Mn ions take the Sn sites which is revealed by the XRD, diffusion reflectance spectrum (DRS) and Raman scattering. With the increase of doping level x, the optical absorption edge shifts towards higher wavelength and is smoothened gradually, meanwhile the Raman spectrum shows that Raman mode is also changed. The photoluminescence spectrum under magnetic field shows that near-infrared luminescence is probably related to Sn ions. The magnetization measurement demonstrates that Mn-doped BaSnO3 system exhibits ferromagnetism at low temperature, which can be explained by the F-center exchange (FCE) mechanism.
Crystal structures and optical properties of(Fe, Co)-codoped ZnO thin films
Authors: Zhang Li  , Xu Ming  , Yu Fei  , Yuan Huan  , Ma Tao  ,   Key Lab. of Information Materials of Sichuan Province, School of Electrical and Information Engineering, Southwest University for Nationalities, Chengdu 610041, China
Published: December 2020

The Fe, Co-codoped Zn0.9FexCo0.1-xO (x=0, 0.03, 0.05, 0.07) thin films are fabricated on the glass substrates by sol-gel method. The surface morphologies, crystal structures, elements and optical properties of the films are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectrum. The XRD results reveal that all the ZnO films are of wurtzite structure. The diffraction peaks of the clusters, oxide or other impurity phase related to Fe and Co are not observed in the samples. This indicates that codoped is beneficial to the improvement on the dispersion of Fe or Co in ZnO. XPS results reveal that Co elements exist as Co2+, Fe elements exist as Fe2+ and Fe3+, but the increase of relative concentration of Fe leads to the increase of Fe3+ content. The ultraviolet emission peak and blue double emission are observed in the PL spectra of all the samples. Compared with the undoped ZnO film, the Co-codoped ZnO film has a blue shift of ultraviolet emission peak of Fe, the unchanged position of the blue double emission peak, and the weakened luminous intensity. Moreover, the green luminescence peak of the doped ZnO film almost disappears. Finally, the luminescence mechanisms of Fe, Co-codoped ZnO films are discussed by combining the microstructures and compositions of the samples.
Primary spectrum pyrometry based on radiation measurement within a finite solid angle
Authors: Xin Cheng-Yun  , Cheng Xiao-Fang  , Zhang Zhong-Zheng  ,   Department of Thermal Science and Energy Engineering, USTC, Hefei 230027, China
Published: December 2020

The true surface temperature for an object can be determined by measuring emitted radiation. Primary spectrum pyrometry should be generally carried out by radiation measurement within an infinitesimal solid angle or within a finite solid angle in the case of diffuse emission, so that the radiation thermometry equations become a closed system for temperature and other undetermined parameters. The radiation thermometry equation with linear emissivity model is obtained, which can be used to measure the temperature of the object with non-diffuse emission within a finite solid angle. This equation is universal in radiation measurement, based on which equations for primary spectrum pyrometry are deduced. These equations are also universal in radiation measurement, in which the emissivity scales under different measurement conditions are limited to the same range, but have different physical meanings.
Sensitivity of delta-P1 approximation model to the reduced scattering parameter
Authors: Tian Hui-Juan  , Niu Ping-Juan  ,   Tianjin Key Laboratory of Advanced Electrical Engineering and Energy Technology, School of Electrical Engineering and Automation Tianjin Polytechnic University, Tianjin 300387, China;,   Engineering Research Center of High Power Solid State Lighting Application System, Tianjin 300387, China
Published: December 2020

For spatial-resolved diffuse reflectance, the sensitivity expression to the reduced scattering parameter μs' is derived and numerically analyzed in the two-point-source delta-P1 approximation of transport theory, and the influences of the scattering parameter μs' on the delta-P1 approximation reflectance, hybrid diffuse approximation reflectance, and diffusion approximation reflectance are also compared. The results show that the optical properties of biological tissue can be better described by the delta-P1 approxiamate model in relatively high scattering and absorbing medium for a short souce-detector separation; the optimum probe spacing ρopt is obtained and approximately equal to 2.7-4 transport mean free path for the reduced albedo a'>0.83, at which a variable reduced scattering coefficient has the smallest effect on the measurement of optical absorption in the turbid medium and ρopt reduces with the scattering parameter μs' increasing. The study is of great significance for optimizing the probe geometry and measuring the optical parameters of biological tissues.
A nnovel wide field fluorescence sectioning microscope based on polarization filtering image enhancement and dynamic speckle illumination
Authors: Wen Qiao  , Wang Kai-Ge  , Shao Yong-Hong  , Qu Jun-Le  , Niu Han-Ben  ,   Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
Published: December 2020

We propose a novel wide-field fluorescence sectioning microscope based on polarization filtering image enhancement and dynamic speckle illumination in this article. A new type of polarization filtering image enhancement technology, based on the differences in polarization characteristic between excitation light and fluorescence, is used to filter out the excitation light and enhance image quality. The dynamic speckle illumination is employed to achieve the wide field fluorescence sectioning which has many advantages, such as simple configuration, low cost, rapid response and easy operation. The experimental results indicate that our filtering method can be utilized to improve the image quality significantly, and the dynamic using speckle illumination can be employed to achieve optical sectioning with a wide field and a high vertical resolution capability. Our study is not only to enrich the technological method to extract the weak fluorescence signal from the strong excitation light, but also to provide a significant reference for developing a light wavelength tunable multi-spectral fluorescence microscope with rapid response.
Experimental research on X-ray radiation and ablation of an Ag foil targets irradiated by high intensity 2ω0 laser light beam
Authors: Liu Shen-Ye  , Huang Yi-Xiang  , Hu Xin  , Zhang Ji-Yan  , Yang Guo-Hong  , Li Jun  , Yi Rong-Qing  , Du Hua-Bing  , Ding Yong-Kun  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The characteristics of radiation and ablation are investigated for an Ag foil irradiated with 2 ns, ～5×1014 W/cm2, 526.5 nm laser at SGII laser facility. The flight trajectory and velocity of the Ag foil are measured by X-ray streak camera. The experimental results show that they are in good agreement with simulations of one-dimensional radiation hydrodynamics code multi-1d using a flux-limited f=0.01. A rocket model is used to fit the experimental data, and the mass ablation rate and ablation pressure are obtained. The L-shell X-ray conversion and spectra of the laser-produced Ag plasma are measured with a Bragg crystal spectrometer and an array of X-ray diodes. The design for X-ray backlighting radiograph experiments will benefit from these experimental results. The result and method presented in this article are significant for the ablation research on the capsule shell and cavity wall material in laser fusion ignition experiment.
A study of LED with surface photonic crystal structure fabricated by the nanoimprint lithography
Authors: Peng Jing  , Xu Zhi-Mou  , Wu Xiao-Feng  , Sun Tang-You  ,   College of Sciences, Wuhan University of Science and Technology, Wuhan 430081, China;,   School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

Surface photonic crystal (PC) structure can improve the external quantum efficiency of light-emitting diode (LED). However, it is very difficult to fabricate large area and uniform nanometer photonic crystal structure in this field. In this paper, two-dimensional PC with hole-like structure is successfully transferred to the surface of gallium nitride LED (GaN-LED) by the mental-polymer double-layer mask dry etching technology combined with the nanoimprint lithography. The large area nanometer PC patterns with pore diameter of 240 nm and period of 450 nm are obtained. The results show that the photoluminescence peak intensity of LED with the PC structure is 7.2 times higher than that of the conventional LED.
Phase-change behaviors in Ga30Sb70/Sb80Te20 nanocomposite multilayer films
Authors: Wang Chang-Zhou  , Zhu Wei-Ling  , Zhai Ji-Wei  , Lai Tian-Shu  ,   Functional Materials Research Laboratory, Tongji University, Shanghai 200092, China;,   Thin Film Optoelectronic Technology Center, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China;,   State Key Laboratory of Optoelectronic Materials and Technology, Department of Physics, Sun Yat-Sen University, Guangzhou 510275, China
Published: December 2020

Novel Ga30Sb70/Sb80Te20 nanocomposite multilayer films are prepared by alternate sputter deposition of two independent targets of Ga30Sb70 and Sb80Te20 in a magnetron sputtering system. The influence of layer thickness of Ga30Sb70 on the phase-change behavior of Ga30Sb70/Sb80Te20 multilayer film is investigated. The results show that the crystallization temperature can be controlled by adjusting the layer thickness of Ga30Sb70. The crystallization temperature increases with increasing the layer thickness of Ga30Sb70. The optical band gap is also found to increase with increasing in the layer thickness of Ga30Sb70. Transient crystallization dynamics of Ga30Sb70/Sb80Te20 multilayer film induced by single picosecond laser pulse pumping, is studied. The reversible phase transition between amorphous and crystalline state can be achieved by using picosecond laser pulses with different fluences.
Vibrational spectra and first principles calculation of BaBPO5 crystal
Authors: Zhang Ji  , Wang Di  , Zhang De-Ming  , Zhang Qing-Li  , Wan Song-Ming  , Sun Dun-Lu  , Yin Shao-Tang  ,   Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China;,   Chinese Academy University, Beijing 100049, China;,   Anhui Xinhua University, Hefei 230088, China
Published: December 2020

In this paper, the lattice vibrational modes of the nonlinear optical crystal BaBPO5 are studied using polarized Raman spectrum and the first-principles calculation. The polarized Raman spectra are obtained in different configurations and recorded in a range of 100-1600 cm-1. Combining the experimental data of the FT-IR spectrum, the lattice vibrational modes of the internal and external vibrations are analyzed by the factor group analysis method. The results indicate that the primary Raman peaks of the BaBPO5 crystal are ascribed to the internal vibrations of the PO4 and BO4 tetrahedrons, and the vibrations of the PO4 tetrahedron show strong Raman- and IR-activity. On the other hand, the first-principles calculation indicates the correlation of the vibrational modes with the atomic activities. Especially, the Raman peak located at 672 cm-1 is ascribed to the vibration of the B-O-P bond, which is the connector between the PO4 and BO4 tetrahedron. These results obtained in this work are important for understanding the micro-structures of the BaBPO5 crystal, and the further study on the crystal growth mechanism.
Nonlinear dynamic model and chaotic characteristics of mechanical thastic energy storage unit in energy storage process
Authors: Yu Yang  , Mi Zeng-Qiang  ,   State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Baoding 071003, China
Published: December 2020

A new way of energy storage based on mechanical elasticity is proposed. Nonlinear dynamic model of permanent magnet motor based mechanical elastic energy storage unit is derived, and the chaotic behaviors under certain parameter values and operation conditions are demonstrated. The linear stability of the nonlinear dynamic model is analyzed. Based on the operation parameters of the 0.16 kWh/0.8 kW unit that is being developed in our laboratory, three-dimensional nonlinear model is reduced to two-dimensional projection subsystem with varying parameters. Then the chaotic property of the unit is analyzed by coordinate plane projection method, the changing relationship between the locations of equilibrium point, characteristic equation of reduction subsystem and varying parameters is discussed, and the chaotic behavior is numerically verified. The issue caused by poor applicability of analytical methods and solved only by simulation is solved to some extent at a theoretical analysis level.
Visible light emission produced by interaction of highly ionized Krq+ ions with a Al surface
Authors: Yang Zhao-Rui  , Zhang Xiao-An  , Xu Qiu-Mei  , Yang Zhi-Hu  ,   Ion Beam and Optical Physical Joint Laboratory of Xianyang NormalUniversity and Institute of Modern Physics, Chinese Academy of Sciences, Xianyang 712000, China;,   Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
Published: December 2020

The spectrum range from 300 to 600 nm is measured with low energy (V≈0.01 VBohr) highly charged Krq+ ions (q=8, 10, 13, 15, 17) impacted on Al surface. The results show that the spectral lines are induced by the impact of low-energy ions on Al surface, and that these lines belong to the sputtered atoms, ions, and the incident ions which are neutralized. The intensity of emission line increases with the projectile potential. The electron of Al can be efficiently excited to the 4s state by the higher potential energy compared with the excited state of 3d.
A data inversion method for electromagnetic scattering from large-scale layered medium
Authors: Zhang Yu  , Zhang Xiao-Juan  , Fang Guang-You  ,   Key Laboratory of Electromagnetic Radiation and Sensing Technology of Chinese Academy of Sciences, Institute of Electronic, Chinese Academy of Sciences, Beijing 100190, China;,   University of Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

An inversion method for electromagnetic scattering echo data from large-scale layered medium is presented to simultaneously retrieve the electromagnetic property parameters of the medium. Firstly, the inversion is converted into an optimization problem. Then the simulating annealing algorithm is adopted to find the optimal solution by taking full advantage of the algorithm global optimization. Besides, the search control strategy of the algorithm is optimized so that the algorithm can adaptively adjust the search step in the optimal solution search process. The search efficiency of the algorithm is improved by these optimizations. Results show that the proposed method can achieve an accurate result in the inversion of the characteristic parameters of large-scale layered media as well as a strong anti-noise ability. The inversion method presented can be applied to the Mars/lunar radar echo data inversion and analysis of underground layered medium.
Intensity distribution of the flat-topped beam propagating through the thick nonlinear medium with defects
Authors: Chen Xue-Qiong  , Chen Zi-Yang  , Pu Ji-Xiong  , Zhu Jian-Qiang  , Zhang Guo-Wen  ,   Department of Information Science and Engineering, HuaqiaoUniversity, Xiamen 361021, China;,   National Laboratory on High Power Laser and Physics, ShanghaiInstitute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

Based on the nonlinear Schrödinger equation and Fourier transformation, the intensity distributions of the high power flat-topped beam propagating in the nonlinear medium and the free space are studied. The influences of the defects on medium surface on the intensity evolution of flat-topped light beam in the medium and the free space are analyzed. The results show that the larger the beam order, the poorer the beam self-focusing property is, and the closer to the back surface of the medium the position related to the maximal intensity point is a stronger initial intensity, a thicker medium or a higher nonlinear coefficient will lead to a stronger self-focusing property. The defects on the surface of medium will produce a relatively large intensity, closer to the back surface of medium. The effect of the phase modulated defect on the intensity evolution is greater than that of amplitude modulated defect.
Nonlocal dark soliton and its linear stability analysis
Authors: Gao Xing-Hui  , Zhang Cheng-Yun  , Tang Dong  , Zheng Hui  , Lu Da-Quan  , Hu Wei  ,   Department of Electrical and Information Engineering, GuangzhouUniversity, Guangzhou 510006, China;,   Laboratory of Photonic Information Technology, South China NormalUniversity, Guangzhou 510631, China
Published: December 2020

Due to its future use in communication area, nonlocal spatial optical soliton has been a hot research topic recently. However, because of its special border condition, little research has been done on spatial dark solitons especially on its linear stability. In this paper, a method to analyze linear stability of nonlocal spatial dark soliton is put forward, moreover a numerical simulation and analysis is done on the linear stability of (1+1)-dimensional fundamental and second-order dark soliton in thermal nonlinear medium. Numerical results show that (1+1)-dimensional fundamental nonlocal dark solitons are always stable in their entire existence domain, while second-order dark solitons are oscillatorily unstable and the width of unstable domain depends on propagation constant and nonlocality degree of thermal nonlinear medium. The propagation graphs of initial input with noise addition confirms the correctness of linear stability analysis results.
Resonance theory of SH wave total reflection tunnel effect in 1D solid-solid infinite cycle phononic crystal
Authors: Liu Qi-Neng  , Liu Qin  ,   College of Computer Science and Information Engineering, Chongqing Technology and Business University, Chongqing 400067, China;,   Design and Art Institute, Chongqing Technology and BusinessUniversity, Chongqing 400067, China
Published: December 2020

Using the boundary conditions the SH wave transfer matrix is derived in one-dimensional (1D) solid-solid photonic crystal, and the dispersion relation of the SH wave is obtained. The resonator model 1D infinite cycle photonic crystal is established, and the wavelength formula of SH wave total reflection tunnel effect is investigated using the resonance condition of resonator. The physical mechanism of SH wave total reflection tunnel effect in the 1D solid-solid infinite cycle phononic crystal is explained.
A new repulsive model for solid boundary condition in smoothed particle hydrodynamics
Authors: Han Ya-Wei  , Qiang Hong-Fu  , Zhao Jiu-Ling  , Gao Wei-Ran  ,   No. 601 Xi’an Hi-Tech Institute, Xi’an 710025, China
Published: December 2020

Compared with traditional mesh method the smoothed particle hydrodynamics (SPH) is unable to directly implement the solid boundary conditions, which hinders its further application to engineering. Therefore, a new repulsive model is deduced based on the Galerkin method of weighted residuals and traditional repulsive methods. Compared with traditional repulsive models, this model does not include unknown parameters; it can avoid fluid particles penetrating wall surface effectively without reducing the size of boundary particle, and also it avoids the oscillation of fluid particles around the boundary in speed and pressure. The new method is examined and compared with traditional methods using four numerical examples including static dam on a fixed boundary, a dam-break flow on a fixed boundary because of gravity, fluid still gradually in a tank because of gravity, dam-break. It is demonstrated that SPH with this new method overcomes the disadvantages in traditional methods, and that this method is an effective method for solid boundary condition.
Josephson effect in ferromagnetic d-wave superconductor/ferromagnet/ferromagnetic d-wave superconductor junctions
Authors: Jin Xia  , Dong Zheng-Chao  , Liang Zhi-Peng  , Zhong Chong-Gui  ,   School of Physical Science and Technology, Suzhou University, Suzhou 215006, China;,   School of Science, Nantong University, Nantong 226019, China
Published: December 2020

By solving a self-consistent equation for the ferromagnetic d-wave superconducting gap and the exchange energy, we study the Josephson current in the ferromagnetic d-wave superconductor/ferromagnet/ferromagnetic d-wave superconductor junctions. In the Josephson critical current, there are two oscillation components with different periods. It is found that the short-period component can be separated from the long-period one by increasing the exchange energy in ferromagnet and the barrier strength at the ferromagnet/ferromagnetic d-wave superconductor interface, and vice versa. Under a certain thickness for the ferromagnet, exchange energy for the ferromagnetic d-wave superconductor may increase the critical current in the case of a parallel alignment of the magnetization in the ferromagnetic d-wave superconductor.
Gradient calculation based ensemble variational method and its application to the inversion of the turbulent coefficient in atmospheric Ekman layer
Authors: Han Yue-Qi  , Zhong Zhong  , Wang Yun-Feng  , Du Hua-Dong  ,   Institute of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing 211101, China;,   National Key Laboratory on Electromagnetic Environmental Effects and Electro-optical Engineering, PLA University of Science and Technology, Nanjing 211101, China
Published: December 2020

The accurate value of the turbulent coefficient in Ekman layer of atmosphere is quite important for the numerical weather prediction and pollutant diffusion calculation. In the paper, based on ensemble method and variational method, the ensemble variational retrieval method is proposed, and the gradient of objective function is calculated with the method. Two calculation procedures are also given based on the linear condition of forward model. The inversion numerical experiments of the turbulent coefficient using ensemble variational method and two calculation flow process are carried out, and the results show that the method has the simple and convenient characteristics, and the turbulent coefficient can be retrieved accurately by observational data.
Application of extended Fourier amplitude sensitivity test (EFAST) method in land surface parameter sensitivity analysis
Authors: Wang Jian-Dong  , Guo Wei-Dong  , Li Hong-Qi  ,   ICGCR, School of Atmospheric Sciences, Nanjing University, Nanjing 210093, China;,   School of environment, Tsinghua University, Beijing 100084, China;,   Numerical Weather Prediction Center, China Meteorological Administration, Beijing 100081, China
Published: December 2020

In this paper, we explore the application of extended Fourier amplitude sensitivity test (EFAST) to land surface parameter sensitivity analysis. Based on observations of Tongyu site (Jilin province) at a degraded grassland in 2008, the EFAST method is verified and applied. The sensible heat flux and latent heat flux are used as the test variables. With the full consideration of the sensitivity of individual parameters, the coupling between the parameters is taken into account. We explore the influence on the nonlinear system under the constraints of the interaction of multiple land surface parameters with a quantitative analysis. The results show that sand content in the soil (sand) and minimal porosity of permeable water are the key factors which affect the heat sensible flux and latent heat flux significantly, which is consistent with the existing result. The sensitivity result confirms the feasibility of the EFAST method. The results of this paper are expected to guide people in designing the field observation and development of parameterization schemes in land surface model.
Simulation and experimental results of evacuation of pedestrian flow in a classroom with two exits
Authors: Chen Liang  , Guo Ren-Yong  , Ta Na  ,   College of Computer Science, Inner Mongolia University, Hohhot 010021, China
Published: December 2020

A microscopic pedestrian model based on cellular automata is proposed and three groups of experiments on pedestrian evacuation from a double-exit room are conducted to investigate the route choice of pedestrians during evacuation. In the model, the route-choice behavior of pedestrians is affected by the route distance from the pedestrians to the exit, the capacity of the frontal route, and the repulsive force between pedestrians. Through the analysis of the video recordings, certain conclusions related to the route choice of pedestrians in these experiments are obtained. Model parameters are calibrated by the experimental data. Simulation results indicate that the model can reproduce the evacuation behavior of pedestrians in the room effectively and evacuation time is an increasing linear function of student number. The present study is helpful for devising evacuation strategies and schemes in buildings that are similar to the room.
Structural, electronic and magnetic properties of ConAl (n= 18) clusters
Authors: Lü Jin  , Qin Jian-Ping  , Wu Hai-Shun  ,   School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004, China
Published: December 2020

Based on DFT-GGA calculations, we systematically investigate the structures, electronic and magnetic properties of ConAl (n= 18) clusters. The results indicate that the aluminum prefers to maximize the number of Co-Al bonds by selecting the site which increases the coordination of cobalt atoms with Al. The doped Al makes the stability of ConAl clusters weakened and the magnetism decreased as compared with that of Con+1 clusters. The reduction magnitude of magnetism of the doping Al accords well with recent Stern-Gerlach experimental result for larger ConAlM clusters. In all of the ConAl alloy clusters, the Al atom is found to be aligned antiferromagnetically with its neighbor Co atoms except for Co4Al. As compared with the magnetism of pure Co cluster, the magnetism of ConAl cluster is reduced, which is attributed mainly to nor-magnetism Al element embeding and the weakening of spin polarization of the Co atoms.
Study of nonlinear acoustic field of high intensity focused ultrasound by the fractional wave
Authors: Sun Jian-Ming  , Yu Jie  , Guo Xia-Sheng  , Zhang Dong  ,   Institute of Acoustics, Key Laboratory of Modern Acoustics (Nanjing University), Ministry of Education, Nanjing 210093, China;,   The Traditional Chinese Medicine Hospital of Jiangsu Province, Nanjing 210029, China
Published: December 2020

The acoustic energy distribution of high intensity focused ultrasound (HIFU) is influenced by the attenuation and the dispersion of the biological tissue. In this paper we modify the KZK equation according to the fractional wave equation, in order to accurately describe the sound field of HIFU. The theoretical and experimental studies of frequency dependences of attenuation and sound speed examine the validity of the fractional wave equation. Furthermore, the numerical simulation of HIFU field is performed using the modified KZK equation. The results demonstrate that the introduction of the fractional derivative equation could solve the problems of the attenuation and sound dispersion, leading to the accuracy improvement of HIFU therapy.
Investigation into the turn-off mechanism and time of IGBT based on voltage and current
Authors: Liu Bin-Li  , Liu De-Zhi  , Luo Yi-Fei  , Tang Yong  , Wang Bo  ,   National Key Laboratory of Vessel Integrated Power System Technology, Naval University of Engineering, Wuhan 430033, China
Published: December 2020

Based on semiconductor physics and the essential structure of IGBT, the turn-off mechanism of IGBT is deeply discussed regarding the problem of turn-off time changing with voltage and current. The laws of turn-off time changing with voltage and current are deduced, i.e., the turn-off time increases with voltage increasing and decreases with current increasing. The physical mechanisms of the laws are found out. The simulation results and experimental results, demonstrate that the derived and the existing law are constant, thereby proving the correctness of the derived law. It is put forward that the law of IGBT turn-off time changing with current and voltage accords with the complex law of exponent and hyperbola. For further studying the IGBT turn-off mechanism and solving the engineering puzzles including the power electronic dead time setting, the present study is significant in theory and practical application.
Dielectric property and relaxation mechanism of CaCu3Ti4O12 ceramic
Authors: Cheng Peng-Fei  , Wang Hui  , Li Sheng-Tao  ,   School of Science, Xi'an Polytechnic University, Xi'an 710048, China;,   State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

In this paper, the dielectric property of CaCu3Ti4O12 ceramic is measured by Novocontrol wide band dielectric spectrometer in a temperature range of -100-100 ℃ and frequency range of 0.1 Hz-10 MHz, and the corresponding dielectric relaxation mechanism is discussed. Firstly, on the basis of quantitative analysis of macroscopic shell-core structure, the possibility of colossal dielectric constant (CDC) originating from the surface insulated layer effect is rejected. Secondly, after the analysis of the nature of classical Maxwell-Wagner sandwich polarization and its activation energy, classical Maxwell-Wagner mechanism is also abandoned. Finally, a new model of trapped electron relaxation at the boundary of Schottky barrier is proposed. The new mechanism correctly reflects the essential connection between intrinsic point defects, conductivity and dielectric constant of CaCu3Ti4O12material.
Radiation damage induced by various particles on CC4013 devices
Authors: Li Xing-Ji  , Liu Chao-Ming  , Sun Zhong-Liang  , Lan Mu-Jie  , Xiao Li-Yi  , He Shi-Yu  ,   School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;,   School of Astronautics, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

During serving in orbit, spacecraft will be affected by the radiation environment of the space high-energy charged particles, leading to the performance degradation or even malfunctions of electronic components. The complementary metal oxide semiconductor (CMOS) devices are sensitive to ionization damage. Therefore, it is valuable to research the mechanism of radiation effects on CMOS devices, and is significant to engineering and theory. The CC4013 CMOS integrated circuits are irradiated with 60 MeV Br ions, 5 MeV protons and 1 MeV electrons. Based on the data calculated by Geant4 code, the ionizing absorbed dose induced by 60 MeV Br ions is greatest, and the ionizing absorbed dose induced by 1 MeV electrons is lowest. The degradation of CC4013 device during the irradiation test is in-situ measured with Keithley 4200-SCS semiconductor characteristic system. From the experimental results, the threshold voltage degradation in CC4013 under an exposure of 1 MeV electrons is greatest at the same dose, a little lower under 5 MeV protons, and lowest under 60 MeV Br ions.
An efficient management strategy for enhancing traffic capacity in scale-free networks
Authors: Cai Jun  , Yu Shun-Zheng  ,   Department of Electronics and Communication Engineering, Sun Yat-Sen University, Guangzhou 510006, China;,   School of Electronic and Information , Guang Dong Polytechnic Normal University, Guangzhou 510665, China
Published: December 2020

Previous research has shown that the community structure of the network well significantly affect information transmission, and the obvious community structure will significantly reduce the network transmission performance. To address the problem, first we define the link importance to communities, which is based on the spectrum of network adjacency matrix. Then we propose a topological management strategy called community weaken control strategy (CWCS) to enhance traffic capacity, which weakens the community structures by logically closing or cutting some links with great link importance. We implement the scheme in both a global shortest-path routing strategy and local routing strategy, and compare it with the previous scheme HDF that removes the links among hub nodes. The simulation results show that the traffic capacity can be greatly enhanced and the average transport time is effectively reduced under the shortest path routing strategy. Under the local routing strategy, the traffic capacity can also be greatly enhanced when the tunable parameter lies in a range from 0 and 2.
Influence of radiation electron energy on deep dielectric charging characteristics of low density polyethylene
Authors: Li Sheng-Tao  , Li Guo-Chang  , Min Dao-Min  , Zhao Ni  ,   State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

The interactions between high-energy charged particles and spacecraft insulating materials can cause deep dielectric charging and discharging, leading to spacecraft anomalies. In this paper, we establish a unipolar charge transport physical model of deep dielectric charging, according to the charge distribution and energy deposition of incident electrons and nonlinear dark conductivity and radiation induced conductivity (RIC) of material. Under the irradiation of electrons with different energies (from 0.1 to 0.5 MeV), the charge transport process of low density polyethylene (LDPE) can be obtained through solving the charge continuity equation and Poisson's equation. The calculation results show that the maximum electric field decreases with the increase of radiation electron energy. When radiation electron energy is less than 0.3 MeV, the distribution of the maximum electric field is similar to the change of the electron beam density. When the electron beam density is more than 3×10-9 A/m2, the maximum electric field will be greater than breakdown threshold (about 2×107 V/m), and it has higher risk of electrostatic discharge (ESD). With the increase of incident electron energy, the critical electron beam density will increase. When the radiation electron energy is 0.4 MeV, the critical electron beam density is 6×10-8 A/m2. When the radiation electron energy is more than 0.5 MeV, it seems that no electrostatic discharge (ESD) will occur in a range from 10-9 to 10-6 A/m2. The physical model has the great significance for further studying deep dielectric charging, evaluating the charged degree of spacecraft in space environment and designing protection devices.
Sex, Gender, Sexuality: Subalternity in Jeffrey Eugenides’ Middlesex
Authors: Faghfori Soheila , Chatrzarnegari Zeinab , Zohdi Esmaeil
Published: December 2020

In contrast with what is widely emphasized and academically discussed, subalternity emerges in a broad spectrum. The current research discusses sex, gender and sexuality as fertile grounds of subalternity in Jeffrey Eugenides’ Middlesex. Although the Classical Marxist tradition submits “class” as the only narrative of oppression and inequality, Gramsci’s Marxism can account for a wider range of narratives, namely, sex, age, race, gender and sexual orientation, and, subsequently, replaces “the proletariat” with “the subalterns.” Gramsci divided superstructure in two parts (civil society and political society) and traced the footsteps of oppression and subordination through everyday lives by concepts such as “hegemony,” “civil society,” and “common sense.” As well as Gramsci, Judith Butler draws attention to the legislation of norms in the social domain. Heterosexuality, sexual dimorphism and masculine/feminine dichotomy are norms which are legislated and hegemonic through the institutions of civil society and shape people’s common sense about sex, gender and sexuality. “Normalization” and “recognition,” to employ Butler’s words, occur based on the norms and turn the outsiders into the subalterns. In this regard, this study discusses intersex Cal/lie and homosexual Sourmelina as subalterns challenging the normative sex, gender and sexuality. The Stephanides family, New York Public Library, Orthodox religion, Sophie Sassoon’s beauty parlor and Ed’s barbershop are all civil society institutions that play a significant role in dissemination of heteronormativity, sexual dimorphism and masculine/feminine dichotomy and ,thereby, subalternity of Cal/lie and Sourmalina.
The Translatability of Some Qur’anic Verbal Irony into English: A Comparative Stylistic and Pragmatic Analytical Study
Authors: Mohammed Alhaj Ali Albashir
Published: December 2020

The current study aims to examine through lexical stylistic analysis and comparison, the differences and the disparateness of meaning and style in rendering the Quranic verbal irony into English, in the work of Mohammed. A.S Abdel Haleem, Mohammed. M Pickthall and Mohammed Khan and Mohammed Taj Al-Din Al-Hilali . Also, the study aims to investigate how the three translators deal with the Quranic verbal irony in their translations into English. This has its powerful consequence in attaining a better understanding on the part of the Holy Quran translators and subsequently of English language receptors in general and for non- Arabic Muslims in particular, where the Qur’anic verbal irony concerned. Also, the study aims to identify the translation strategies employed by the three translators in rendering the Quranic verbal. irony Moreover, the study revealed that the Qur’anic verbal irony is conspicuous occurrence in the Holy Quran and that the process of rendering them into English is generally problematic for the reasons such as linguistic and cultural divergences and discrepancies. Finally, the study gives two ideas; firstly, the equivalence in translation should be examined as a concept that holds a place on a scale that can begin very equivalent to inequivalent. Secondly, better translation of the Holy Quran should bear intelligibility in terms of a total impact of the Message on the language receptor.
“Self-sacrifice may be Quite Wrong”: Women’s Education and Finances in The Odd Women (1893) by George Gissing
Authors: Alam Samiya , Ramli Aimillia
Published: December 2020

In late-nineteenth-century Britain, the surplus number of single women presented an internal crisis that accumulated in a number of debates on the subject in various fields, such as economy and education. While much have been written about these in relation to the social context of the time, little have been said specifically about the way single women and their educational and financial positions are presented in late-nineteenth-century English novels. This paper focusses on George Gissing’s (1857-1903) novel The Odd Women (1893) and its portrayal of single women and the parallel roles played by money and education in the women’s decision to remain unmarried. The method applied in this study is based on contextual as well as textual analyses and interpretation of the novel in light of feminist and Marxist literary theories. This study investigates the impact of socio-economic conditions on the lives of single women towards the end of the nineteenth century. The result of this study shows the novel makes a correlation between women’s level of education and financial situation with their choice to remain single.