bluuebunny/crossref_metadata_2025 huggingface dataset:
Molten salt synthesis, V-doped and magnetic properties of columbite MnNb2O6
Authors: Zhou Chuan-Cang  , Liu Fa-Min  , Ding Peng  , Zhong Wen-Wu  , Cai Lu-Gang  , Zeng Le-Gui  ,   School of Physics and Nuclear Energy Engineering, Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education),Beijing University of Aeronautics and Astronautics, Beijing 100191, China
Published: December 2020

A novel molten salt synthsis technology is developed to prepare single phase and V-doped MnNb2O6powder. The prepared samples are characterized by XRD, SEM, EDS, TEM, HRTEM and SAED. The results show that the MnNb2O6 powder has an orthorhombic structure.and the samples prepared in different molten salts exhibit different shapes:flake shape, rod shape, and rectangular shape. The effects of temperature and doped on structure and morphology are discussed. HRTEM and SAED indicate the rod-shape MnNb2O6 has the properties of anisotropic growth and crystalline integrality. Magnetic properties are measured by superconducting quantum interference device (SQUID) in a temperature range of 2—30 K under a magnetic field of 2T. The magnetic measurement results indicate that MnNb1.8V0.2O6 undergoes an antiferromagnetic transition with a Néel temperature of 5.4 K. Above 20 K, the inverse susceptibility is fitted well to the Curie-Weiss law θ=-33.9 K,C=10.52 K emu mol ·f.u.-1 and effective moment 5.82 μ B can be obtained. With V-doped amount increases, antiferromagnetic interaction increases. According to the Anderson model, the MnNb2-xVxO6 is antiferromagnet in a low temperature range, which is induced by the superexchange interaction of Mn2+-O2--Mn2+.
Numerical simulation of pulsed current tungesteninert gas (TIG) welding arc
Authors: Guo Chao-Bo  , Shi Yu  , Fan Ding  , Huang Jian-Kang  ,   (1)Key Laboratory of Non-ferrous Metal Alloys, The Ministry of Education,Lanzhou University of Technology, Lanzhou 730050, China; (2)State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, China
Published: December 2020

A two-dimensional axisymmetric model of free burning tangsten inert gas (TIG) arc under the action of pulsed current is developed. Using the FLUENT software and choosing appropriate boundary conditions and strongly coupling control equations, a pulsed TIG arc is simulated. The variations of arc form, temperature field, temperature and velocity on the arc axis and surface pressure distribution of the workpiece are obtained and analyzed in the periodic current process; under the action of different values of peak current, duty ratio and pulse frequency, the arc pressure distributions are obtained and analyzed. The results show that they lag behind the variation of pulse current, the variation from base current to peak current is faster, then eventually reaches a relativly stable state; with the increase of peak current, the arc pressure increase greatly; with the increase of duty ratio, the arc pressure increases slowly; with the increase of pulse frequency, the arc pressure cannot reach a stable state gradually, and the max arc pressure tends to decrease.
Long-memory ARFIMA model for DNA sequences of influenza A virus
Authors: Liu Juan  , Gao Jie  ,   School of Science, Jiangnan University, Wuxi 214122, China
Published: December 2020

Influenza viruses are divided into three types: A, B and C. Among them, type A virus is the most virulent human pathogen and causes the most severe disease. In this paper, we propose a new time series model for influenza A virus DNA sequence, i.e.chaos game representation (CGR) radians series. The CGR coordinates are converted into a time series model, and a long-memory ARFIMA(p,d,q) model is introduced to simulate the time series model. We select randomly 10 H1N1 sequences and 10 H3N2 sequences in analysis. we find in these data a remarkably long-range correlation and fit the model reasonably by ARFIMA(p,d,q) model, and also find that we can use different ARFIMA models to identify the two kinds of sequences, i.e. ARFIMA(0,d,5) model and ARFIMA(1,d,1) model that can identify H1N1 and H3N2 respectively.
X-ray pulsar weak signal detection based on Bayesian estimation
Authors: Zhang Hua  , Xu Lu-Ping  , Xie Qing  , Luo Nan  ,   School of Electronic Engineering, Xidian University Xi’an 710071, China
Published: December 2020

Integrated profile, flux and period are three major characteristics of pulsar. Taking advantage of these characteristics, a time domain detecting method is presented based on Bayesian estimation to detect pulsar periodic radiation signals. The signal probability distribution is deduced based on the Poisson distribution model of X-ray pulsar, with noise observation of non-pulse region used as the priori knowledge. The cumulative distribution function of the signal probability is used as a criterion to detect weak signals of X-ray pulsars and extract the phase offset. The RXTE data and the simulation data are used for experimental verification, and the results show that the method outperforms a similar method which is based on the Gauss distribution model, in addition, it can give the phase offset in a certain accuracy.
An integral of a generalized Birkhoff system
Authors: Zhang Yi  , Ge Wei-Kuan  ,   (1)College of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215011,China; (2)Department of Physics, Huzhou Teachers College, Huzhou 313000,China
Published: December 2020

The generalized Birkhoff equations are obtained by using supplementary terms added to the Birkhoff equations. An integral of the Birkhoff equations can be used to the generalized Birkhoff equations.An example is given to illustrate the application of the result.
Model solution of perturbed delays in classical physics
Authors: Wang Na  , Ni Ming-Kang  ,   Department of Mathematics, East China Normal University, Shanghai 200062, China
Published: December 2020

Using the boundary layer corrective method, one type of perturbed model with delays in classical physics is studied. The asymptotic solution for the model is constructed. The asymptotic behaviors of the solution are also discussed.
Soliton solution for the disturbed mKdV coupled system
Authors: Wen Zhao-Hui  , Xu Yong-Hong  , Mo Jia-Qi  ,   (1)Department of Mathematics & Physics, Bengbu College, Bengbu 233030, China; (2)Department of Mathematics, Anhui Normal University, Wuhu 241003, China; Division of Computational Science, E-Institutes of Shanghai Universities at SJTU, Shanghai 200240, China; (3)Institute of Applied Mathematics,School of Statistics and Applied Mathematics,Anhui University of Finance and Economics, Bengbu 233030, China
Published: December 2020

The approximate solution for a class of disturbed mKdV coupled system is considered using a simple and valid technique. We first solve the approximate solution of the soliton for a corresponding complex-valued differential equation using the homotopic mapping method. And then the approximate solution of the soliton for a original disturbed mKdV coupled system is obtained.
Strengthened quantum Hamming bound
Authors: Xing Li-Juan  , Li Zhuo  , Zhang Wu-Jun  ,   State Key Lab of Integrated Services Networks,Xidian University,Xi’an 710071,China
Published: December 2020

By studying sets of operators with constant weight we present for the first time an analytical upper bound on the pure quantum stabilizer codes whose underlying quantum system can be of arbitrary dimension, which outperforms the so far well-known quantum Hamming bound, the optimal analytical upper bound for small code length.
Effects of time delay on transition rate of state in an increasing process of Logistic system
Authors: Yang Lin-Jing  ,   College of Chinese Medicine, Yunnan University of Traditional Chinese Medicine, Kunming 650500, China
Published: December 2020

The effects of time delay on transition rate from metastable state to stable state in a Logistic system are investigated. On the assumption that there is a delay time in the decay process of cell evolution, the expression of the transition rate is derived in the first order approximation under the condition of the small delay time and the steepest-descent approximation. The numerically calculated results indicate that the additive noise, the multiplicative noise and the correlations between additive and multiplicative noises enhance the system transition from metastable state to stable state. However, such a transition is restrained by the time delay, i.e., the time delay enhances the stability of the system.
Chaos in a neuron model with adaptive feedback synapse: Electronic circuit design
Authors: Li Chun-Guang  , Chen Jun  ,   (1)Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China; (2)Department of Physics and Electronic Engineering, Dingxi Teachers’ College, Dingxi 743000, China; Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
Published: December 2020

In a neuron model with adaptive feedback synapse, with the change of parameters, the existence of two coexisting chaotic attractors, switching from the coexisting chaotic attractors to a connected chaotic attractor,and then switching back to the two coexisting chaotic attractors in this model were recently reported. An electronic circuit design for this model is described in detail in this paper. The circuit design of the non-monotonous activation function unit is also considered in detail. The designed circuits are simulated using the Electronic Workbench (EWB) software. Simulation results demonstrate that the dynamical behaviors of the designed circuit are closely similar to those in numerical simulations.
Hopf bifurcation control of the Rössler system based on Washout filter controller
Authors: Wu Zhi-Qiang  , Sun Li-Ming  ,   Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300072,China
Published: December 2020

The Washout filter is adopted to control Hopf bifurcation in Rössler system. The effect of its parameters on the position of bifurcation point, the bifurcation type, and the amplitude of periodic solution is discussed in detail. Based on Routh criterion, the stability region in parameter space is found out firstly. Then the influence of the filter’s time constant and the linear gain on the location of bifurcation point is analyzed. By using the Direct Normal Form method, the normal form of the controlled Rössler system is deduced and the coefficient of resonant term is expressed as a function of the nonlinear gain. It is revealed that, by changing the sign and the absolute value of the real part of the coefficient, the nonlinear gain can modify the periodic solution’s amplitude and Hopf bifurcation type. All the results obtained are verified by numerical simulation.
A fast algorithm for multivariable generalized predictive control of Rössler hyperchaotic system
Authors: Chen Zhi-Wang  , Liu Wen-Long  ,   (1)Key Lab of Industrial Computer Control Engineering of Hebei Province, Yanshan University, Qinhuangdao 066004, China; (2)Key Lab of Industrial Computer Control Engineering of Hebei Province, Yanshan University, Qinhuangdao 066004, China; The Applied Technology College of Daqing Petroleum Institute, Qinhuangdao 066004, China
Published: December 2020

A kind of fast multivariable generalized predictive control algorithm for Rössler hyperchaotic system is proposed. The chaotic system with improved recursive least squares parameter of time-varying forget factor is identified, then the output signals of the system follow fast the reference ones for the application of the feedforward gain matrix and softing coefficient matrix in regular performance index function of multivariable generalized predictive control. Moreover, the reduction of inverse matrix dimensions leads to smaller amount of computation of the algorithm. The simulation results show the effectiveness and practicability of this algorithm.
Tracking control and parameters identification of a class of chaotic systems with unknown parameters
Authors: Li Nong  , Li Jian-Fen  , Liu Yu  ,   (1)The Engineering Institute,Air Force Engineering University, Xi’an 710038, China; (2)The Science Institute,Air Force Engineering University, Xi’an 710051, China
Published: December 2020

A tracking control method is proposed for a class of chaotic systems with unknown parameters. The controller and recognizing rules of unknown parameters are designed based on Lyapunov stability theory. The method is illustrated by applications to unified chaotic systems and the simulation results showed the effectiveness of the proposed scheme.
Generalized projective synchronization of chaotic systems via modified active control
Authors: Li Zhen-Bo  , Zhao Xiao-Shan  , Wang Jing  ,   School of Science, Tianjin University of Technology and Education, Tianjin 300222, China
Published: December 2020

Based on Lyapunov stability theory, by introducing a special matrix structure, a modified active control is proposed for the generalized projective synchronization of chaotic system. Compared with the traditional active control, the modified active control is independent of the Routh-Hurwitz criterion, which means the complexity of active control is simplified. The method is successfully applied to the energy resource system and nuclear spin generator system. Compared with other method, the proposed method, which could realize the generalized projective synchronization between both identical systems and different systems, is shown to be simple, direct, stable and efficient. Numerical simulation is provided to show the validity of the theoretical analysis and the effectiveness of the method.
Fractional sliding mode surface controller for projective synchronization of fractional hyperchaotic systems
Authors: Sun Ning  , Zhang Hua-Guang  , Wang Zhi-Liang  ,   School of Information Science and Engineering, Northeastern University, Shenyang 110819, China
Published: December 2020

In this paper, a sliding mode controller with fractional sliding surface is designed for projective synchronization (PS) of fractional hyperchaotic systems via active control theory and sliding mode theory. The existence and the stability of PS between two fractional hyperchaotic systems are studied based on Lyapunov theory, fractional stability theory and the theory of fractional calculus. The criterions for the practical stability of the PS error system are presented also. Numerical simulation of PS between fractional Chen system and a new hyperchaotic system shows the effectiveness of the proposed controller law.
The analysis of traffic congestion and dynamic propagation properties based on complex network
Authors: Fu Bai-Bai  , Gao Zi-You  , Lin Yong  , Wu Jian-Jun  , Li Shu-Bin  ,   (1)Institute of Automation Shandong Academy of Sciences, Shandong Jinan 250014,China; (2)School of Architecture and Unban Planning, Shandong Jianzhu University, Jinan 250014, China; (3)School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044, China; (4)School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044, China; Institute of Automation Shandong Academy of Sciences, Shandong Jinan 250014,China; (5)State Key Laboratory of Rail Traffic Control a
Published: December 2020

The complexity science, as a new crossing discipline, have infiltrated many areas of traffic study. In recent years, studing the problem of urban traffic system with complex network theory offers a new perspective to investigate the generation and propagation of traffic congestion. This paper studies the impact of the network topology on traffic congestion by the improved mesoscopic traffic flow model, and analyzes properties of the occurrence of traffic congestion, which can raise the effective elimination of traffic congestion control strategy as well as make reasonable transportation planning.
Simulation and optimization of grating optical coupling of terahertz quantum well photodetector
Authors: Zhang Rong  , Guo Xu-Guang  , Cao Jun-Cheng  ,   Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
Published: December 2020

The grating optical coupling method is commonly used for detecting the normal incident light with a quantum well photodetector. In this paper, the distribution of electromagnetic field in one-dimensional metal grating terahertz quantum well photodetectors is studied with modal method, and the average light intensity in the active region is obtained. The result shows that, the light intensity in the device can be optimized when the period of the grating is comparable with the wavelength of the terahertz wave in the sample and a proper filling factor is chosen according to the device structure, which will improve the responsivity of the device.
Time-domain scattering properties of microstrip array antennas
Authors: Zhang Xue-Qin  , Wang Jun-Hong  , Li Zheng  ,   (1)Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044, China; (2)Research Institute of Chemical Defense, Beijing 102205, China
Published: December 2020

In this paper, the scattering characteristics of microstrip antenna arrays in time domain are analyzed using finite-difference time domain (FDTD) method. The distributions of scattering field components, Eθ and Eφ, are studied when the polarization and incidence directions of the incident pulse vary. The relationship of time domain waveforms and spectra of the scattering field with the microstrip antenna array structure is analyzed. The effect of ground plane on the scattering field of microstrip patch array is investigated using the field separating approach. It was found that the scattering field of microstrip antenna array with finite ground plane is mainly generated by the edge current on the ground plane. The resonance frequency of microstrip patch array is associated with the polarization direction of the incident pulse, hence, different polarization directions correspond to different spectra of the scattering field.
The study of shape and shape-coexistence of neutron rich nuclei around N=28
Authors: Zhi Qi-Jun  ,   School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001, China
Published: December 2020

With the isospin-dependent Nilsson potential, we calculate the properties of the N=28 nuclei in the framework of macroscopic-microscopic model. The shape and shape coexistence of these nuclei are calculated and discusses. It is shown that strong shape coexistences occur in the ground state of nuclei with N=28 in Na, Mg and Al isotopes. It is pointed out that, the ground state of 42Si is oblate shape and there is no obvious shape coexistence for 42Si.
Calculation and analysis of DPA in the main components of CSNS target station
Authors: Yu Quan-Zhi  , Yin Wen  , Liang Tian-Jiao  ,   Engineering Centre of CSNS Target Station and Instruments, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

The damage energy cross sections and displacement cross sections of W, SS316 and Al-6061, which will be used in the CSNS (China Spalllation Neutron Source) target station, were calculated with the high energy transport code MCNPX 2.5.0. The DPA (Displacement Per Atom) distributions were also calculated and anlyzed for the main components in the CSNS target station, such as the W target, the target vessel, the moderators and reflector vessels. Based on the DPA caused by neutrons and protons, the lifetime of these components were estimated. The influence of the proton beam profile on the peak value of DPA for W target and target vessel were also presented. These calculations and analyses are very important for the under going CSNS project.
Isolated intense 38 attosecond pulse generation from the combined laser pulse irradiating the coherent superposition state
Authors: Yu Xu-Ping  , Chen Ji-Gen  , He Long-Jun  , Xu Yuan-Yuan  , Yang Yu-Jun  ,   (1)College of Physics and Electronic Engineering, Taizhou University, Taizhou 318000, China; (2)Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
Published: December 2020

A scheme to efficiently generate an intense short isolated attosecond pulse is presented by the combined laser pulse irradiating the coherent superposition state. The combined pulse is composed of a multi-cycle 800 nm laser and a 1600 nm one. Compared with the case of the fundamental laser irradiating the ground state, the cutoff position is significantly extended from 70th to 280th harmonic, a broadband supercontinuum spectrum with 108 eV spectral width can be produced which directly generates an isolated 38 attosecond pulse, the intensity of which is increased eleven orders of magnitude. Our simulation also shows that the value of the time delay has a large range to keep the isolated sub-50-as pulse generation. Moreover, the value of the time delay in the range between ±0.05π is optinal. This result shows that the scheme appears feasible for an experimental demonstration.
Emission spectra of OH radical (A2Σ+→X2Πr) and its application on high temperature gas
Authors: Yang Qian-Suo  , Jiang Zong-Lin  , Peng Zhi-Min  , Ding Yan-Jun  ,   (1)Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; (2)State Key Laboratory of Power Systems, Dept of Thermal Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

Based on the inherent molecular structure characteristics of the OH radicals, the energy level distribution, the transition frequency and Einstein spontaneous emission transition probability are systematically analyzed and numerically studied. Meanwhile, combined with the spectra experiments, the natural broadening, collision broadening, Doppler broadening and instrumental broadening effects on spectral line shape are analyzed. The dependence of the spectral profile on the rotational temperature, the vibrational temperature, and the spectral function are numerically explored in certain ranges. The corresponding numerical results are also discussed for the emission spectra thermometry, which provides a theoretical basis for the emission thermometry. In experimental, the emission spectra of OH (A2Σ+→X2Πr) system of the hydrogen flames are recorded by the optical multi-channel analyzer and studied. By the fitting of the experimental spectra to the numerically calculated spectra, the corresponding rotational and vibrational temperatures of the hydrogen flames are determined, respectively.
The quasi-classical trajectory study in the reaction C+OH(v=0—3, j=0—3)→CO+H
Authors: Wang Ping  ,   Department of Electronic Engineering, Jinan Vocational College, Jinan 250103, China
Published: December 2020

The effect of reagent vibrational and rotational excitation on the stereodynamics in the chemical reaction C+OH at the collision energy of 1.0 eV has been carried out by using the quasi-classical trajectory method. The vector property of different vibrational and rotational states has been discussed in detail. The results suggest that the vibrational and rotational excitation of OH are very sensitive to the vector property of the C+OH reaction, which is different from the study of the scalar property of the C+OH reaction.
Influence of laser pulse on the photodetachment of H- ion near a metal surface
Authors: Wang Shan-Shan  , Wang De-Hua  , Tang Tian-Tian  , Huang Kai-Yun  ,   College of Physics, Ludong University, Yantai 264025, China
Published: December 2020

Using the closed orbit theory and the formulas of double-pulse laser pulse photodetachment cross section of H- ion near a metal surface, we calculated the laser pulse photodetachment cross section of this system. The results suggest that for the double-pulse laser, if the pulse width is much longer than the particular closed orbit period, the contribution of that closed orbit to the photodetachment cross section is very small. If the pulse width is shorter or can be compared with the particular closed orbit period,the contribution of that closed orbit to the photodetachment cross section is reduced. The cross section depends not only on the pulse width, but also on the time delay and the relative phase of the two pulses. For certain relative phase between the two pulses, the photodetachment cross section is increased; while for other relative phases, the photodetachment cross section is reduced. Therefore, we can use the pulse laser to control the photodetachment process of H- near a metal surface. We hope our results will be helpful for experimental research of photodetachment of negativeion influenced by pulse laser near surfaces.
Theoretical study of geometry structures and stability of OsnN0,±(n=1—6) clusters
Authors: Tang Hui-Shuai  , Zhang Xiu-Rong  , Kang Zhang-Li  , Wu Li-Qing  ,   (1)Research Institute of Higher Education, Jiangsu University of Science and Echnology, Zhenjiang 212003, China; (2)School of Materials Science and Engineering, Jiangsu University of Science and Technology; Zhenjiang 212003, China; (3)School of Mathematics and Physics, Jiangsu University of Science and Technology, Zhenjiang 212003, China
Published: December 2020

The possible geometrical and electronic structures of (OsnN)0, ±(n=1—6) clusters are optimized by using the density functional theory (B3LYP) at the LANL2DZ level. For the ground state structures of (OsnN)0,±(n=1—6) clusters, the average binding energies, second finite differences, dissociation energies and energy gaps are analyzed. The calculated results show that there are many different isomerides in (OsnN)0,±(n=1—6) clusters. With the increase of number of atoms, the N atom tend to the peripheral endpoint; the clusters show "odd - even" oscillation and "magic number" effect. The cluster is more stable when the number of atoms is even than odd. It was found that the Os3N+ and Os5N+ clusters are the most stable and n=4 clusters is the least stable, yet the stability of (OsnN)0,±(n=1—6) clusters have increased significantly than pure osmium clusters.
Selectable electromagnetic response modes and negative refraction in rectangular dielectric metamaterials
Authors: Ding Pei  , Zhou Qiang  , Hu Wei-Qin  , Cai Gen-Wang  , Liang Er-Jun  ,   (1)School of Physical Science & Engineering and Key Laboratory of Materials Physics of Ministry of Education of China, Zhengzhou University, Zhengzhou 450052, China; (2)School of Physical Science & Engineering and Key Laboratory of Materials Physics of Ministry of Education of China, Zhengzhou University, Zhengzhou 450052, China; Department of Mathematics & Physics, Zhengzhou Institute of Aeronautical Industry Management
Published: December 2020

Dielectric resonator is a kind of important building block for metamaterials. Here, we numerically investigated the resonance modes excited in the dielectric resonator whose cross section has different ratios of the length to width. It is found that the cross-sectional aspect ratio has great influence on the excitation sequence of the resonance modes. The magnetic resonance mode is firstly excited for the aspect ratio smaller than 2.2, whereas it is excited at the second resonance for the ratio lager than 2.2. As the turning point, i. e. with the aspect ratio of 2.2, the magnetic mode cannot be achieved. The calculations also show that the magnetic resonance can be tuned by adjusting the direction of the incident electromagnetic wave, thus achieving the polarization control of electromagnetic response. This study provides valuable information for the design and research of novel dielectric-based metamaterials.
Negative refractive index metamaterials based on high-permittivity substrates and metallic structure: design, simulation and experiment
Authors: Yang Yi-Ming  , Wang Jia-Fu  , Qu Shao-Bo  , Xia Song  , Wang Jun  , Xu Zhuo  , Bai Peng  , Li Zhe  ,   Department of Mathematics and Physics, College of Science, Air Force Engineering University, Xi'an 710051, China;,   Department of Mathematics and Physics, College of Science, Air Force Engineering University, Xi'an 710051, China; Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China;,   Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China;,   Synthetic Electronic Information System Research Department, Air Force Engineering University, Xi'an 710051, China
Published: December 2020

By printing single-loop mirror-symmetrical split-ring resonators on high-permittivity substrates, a type of negative index material was realized with less usage of metals and broader negative-index bandwidth than conventional negative index materials. The underlying mechanisms of realizing negative permittivity by means of high-permittivity substrates and of double-negative pass-band were analyzed. The influening factors on the double-negative pass-band were analyzed both numerically and experimentally. By experiments, the proposed method of realizing double-negative property was verified. Both the theoretical and experimental results show that broad double-negative pass-band can be realized using the proposed method.
Implementation of two-element antenna array with right/left-handed transmission line metamaterials
Authors: Zheng Kui-Song  , Wu Chang-Ying  , Wan Guo-Bin  , Wei Gao  ,   School of Electronics and Information, Northwestern Polytechnical University, Xi’an 710072, China
Published: December 2020

To overcome the limitation that the linear transverse dimension of microstrip antenna is of the order of half wavelength, a two-element antenna array has been proposed with composite right/left-handed transmission line metamaterials in this paper. The antenna array is made of two same antenna elements. Each element consists of three radiating patches, interdigital capacitance between two radiation patches and shorted pin connecting radiating patch with ground plane. Therefore, a composite right/left-handed transmission line metamaterials is constituted by radiating patch, shorted pin, antenna of substrate and ground plane. An arched microstrip line is used to connect two antenna elements. The phase difference between two antenna elements is set by adjusting the length of arched microstrip line. S parameters of antenna array obtained by numerical computation are in good agreement of that obtained by measurement. Meanwhile, zeroth-order resonant frequency of two-element antenna array is consistent with that estimated by the circuit theory with extracting equivalent circuit parameters of composite right/left-handed transmission line metamaterials. The peak gain of this antenna array is 6.3dB. Seen from this point, the antenna peak gain is enhanced. When operating in the zeroth-order resonant frequency, physical dimensions of this antenna element are reduced to 0.28λ0×0.1λ0. Here λ0 is a zeroth-order resonant wavelength. The proposed antenna array is a novel venue for antenna miniaturization.
The propagation properties of broadband pulse
Authors: Li Qin  , Guo Hong  ,   College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
Published: December 2020

The propagation of broadband pulse in a medium with electromagnetically induced transparency (EIT) was studied. The results show that if the carrier frequency of pulse is exactly tuned to the center of the transparency window, and the pulse spectrum is broader than transparency window, the pulse is temporally broadened and the delay effect is significant. If the carrier frequency of pulse the is exactly tuned to the region of absorption, and the pulse spectrum is wide with respect to the width of absorption line, the pulse begins to distort after a certain distance and is split into two parts at last. The peak value depends not only on the frequency and intensity of the coupling field, but also on the length of the sample. Under appropriate conditions, strong and time domain narrowed pulse can be obtained in the output light.
Influences of effective gain length and attenuation coefficient on output energy of stimulated Brillouin scattering in water
Authors: He Xing-Dao  , Xia Jian  , Shi Jiu-Lin  , Liu Juan  , Li Shu-Jing  , Liu Jian-An  , Fang Wei  ,   Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
Published: December 2020

In this paper, the effects of attenuation coefficient and effective gain length on output energy of stimulated Brillouin scattering (SBS) in water are investigated theoretically and experimentally. The experimental results indicate that the smaller the attenuation coefficient, the higher the output energy of SBS is. When the energy of incident laser is very high and the effective gain length is long enough, the SBS may obtain high enough energy thereby reach an extremely strong peak power due to the pulse compression; once it exceeds the threshold of SRS or second-order SBS, the SBS is able to excite an SRS or a second-order SBS as a new source and consumes a part of its own energy. Therefore, the longer the effective gain length, the lower the output energy of SBS is.
Study on measuring the kinematic viscosity of liquid medium based on the energy reflectivity of SBS
Authors: Geng Xi-Zhao  , Hasi Wu-Li  , Guo Xiang-Yu  , Li Xing  , Lin Dian-Yang  , He Wei-Ming  , Fan Rui-Qing  , Lü Zhi-Wei  ,   Institute of Opto-Electronics, Harbin Institute of Technology, Harbin 150080, China; National Key Laboratory of Science and Technology on Tunable laser, Harbin Institute of Technology Harbin 150080, China
Published: December 2020

In the paper, a method of measuring the kinematic visicosity of liquid medium based on stimulated Brillouin scattering (SBS) at different temperatures is proposed. The kinematic visicosity of liquid medium, which is related to the temperature, greatly affects the gain coefficient of medium and SBS characteristics. Therefore the kinematic visicosity at different temperatures can be measued by the reflectivity of SBS. In experiment, the kinematic visicosities of water at different temperatures are determined based on SBS in continuum's Nd:YAG seed-injected laser and compared with the results measured from kinematic viscosimeter, and the relative error of the experiment results is less than 5%.
General formulation of nonlinear Thomson scattering of arbitrary polarized laser and optimal conditions for X-ray production
Authors: Zhao Shi-Hua  , Lü Qing-Zheng  , Yuan Su-Ying  , Li Ying-Jun  ,   School of Science, China University of Mining & Technology (Beijing), Beijing 100083, China
Published: December 2020

The general formulation of nonlinear Thomson scattering of arbitrary polarized laser is derived from electrodynamics analytically under relativistic conditions. The extreme condition for high order harmonics is educed from the analytical results. It is found that the circular polarization reaches a maximum while the linear polarization is at its minimum in the fundamental backscattering radiation in the same situations, which makes important consulting sense in the experimental research of X-ray source based on the Thomson scattering mechanism especially for high intensity incident laser pulse cases.
The relationship between conversion efficiency of high-order harmonic generation from atom and wavelength in two-color combined fields
Authors: Cao Wei-Jun  , Cheng Chun-Zhi  , Zhou Xiao-Xin  ,   (1)Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University , Lanzhou 730070, China; (2)Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University , Lanzhou 730070, China; Department of Physics, Changji University, Changji 831100, China
Published: December 2020

By solving the time-dependent Schrödinger equation under velocity gauge with split-operator method, we studied the high harmonics of one-dimensional helium atom exposed to one-color laser field and two-color fields composed of IR field and UV field. And the relationship between conversion efficiency of high-order harmonic generation near the cut-off position and wavelength of the laser (800—2000 nm) was also analyzed. It was found that high-order harmonic conversion efficiency driven by two-color laser field near the cut-off position changes with wavelength as η(λ)∝λ－x,where the x value depends on the intensity of laser field, and the appropriate selection of intensity of combined laser field can improve high harmonic conversion efficiency near the cut-off position.
Study on a novel optical filter by internal reflection and optical rotation
Authors: Zhang Bin  , Pan Xue-Feng  , Tao Wei-Dong  ,   Faculty of Science, Ningbo University, Ningbo 315211, China
Published: December 2020

Based on the optical rotatory dispersion and the isotropy of the sodium chlorate crystal, a new type of optical filter by internal reflection and optical rotation is firstly developed. Due to the speciality of the zero reflectivity when the linearly polarized light is reflected at Brewster angle, the optical filter can give a good filtering effect by using only a single polarizer. The filtering characteristics were analyzed by Mueller matrix and tested by experiment. The results show that the intensity of emitted red or green light can be continuously modulated by changing the angle of the polarizer. The extinction of green or red light appears when the rotation angle of the polarizer is respectively 133.36° or 173.06° relative to the initial position. The isolation of green and red can be about 10 dB.
Ultrasonic frequency coordination relation of the acousto-optic tunable filter
Authors: Cai Hong-Xing  , Li Shi-Jun  , Ren Yu  , Lu Jun  ,   (1)School of Information Technology, Jilin Agricultural University, Changchun 130118, China; (2)School of Science, Changchun University of Science and Technology, Changchun 130022,China
Published: December 2020

In this paper, the ultrasonic frequency coordination relation has been re-designed in the high-dimensional space by the principle of Kernel function nonlinear mapping. The relative deviation of ultrasonic frequency coordination relation from the original formula has been obtained by analyzing I.C.Chang theoretical model and P.A.Gass revised theoretical model concretely, theraby indicating the inadequacy of the two theoretical models; Using the principle of the nonlinear mapping to map the original data samples into a high dimensional kernel space, in other words, translating the nonlinear problem into a linear problem can clarify the relationships not only between ultrasonic frequency and incident angle but also between ultrasonic frequency and optical wavelength, leading to an appropriate kernel function and the improved coordination of the ultrasonic frequency relation.
Maximum ceasing angle of inclination and flux formula for granular orifice flow
Authors: Peng Zheng  , Jiang Yi-Min  ,   School of Physical Science and Technology,Central South University, Changsha 410083,China
Published: December 2020

This work measured mass flux of a granular sample (glass beads) discharged from an inclined orifice for various inclination angles and orifice diameters. It is found that irrespective the orifice sizes, the fluxes all vary linearly with cosine of the inclination angle,and the linearly extrapolated angle of zero-flux,namely the critical angle of flow ceasing, increases linearly with ratio between grain and orifice diameter, tends to the angle of repose in the limit of infinite orifice diameter within an approximation of the Bagnold angle. The results show that the flux formula varying linearly with cosine of inclination angle is capable to reveal behaviors of the critical ceasing angle, a property that the Beverloo formula of which parameters vary with cosine of inclination angle can not describe.
The deformation process of viscous liquid drop studied by using kernel gradient corrected SPH method
Authors: Jiang Tao  , Ouyang Jie  , Zhao Xiao-Kai  , Ren Jin-Lian  ,   Department of Applied Mathematics, Northwestern Polytechnical University, Xi'an 710129, China
Published: December 2020

In this paper, a kernel gradient corrected smoothed particle hydrodynamics (KGC-SPH) method is proposed to simulate the deformation process of a viscous liquid drop. The KGC-SPH method has higher accuracy and better stability than the SPH method, which is verified by simulating the stretching and rotating process of an isothermal viscous liquid drop, and the property of preservation of total angular momentum of the present method is also checked. And then, the formation of a stable spherical liquid drop based on van der Waals model is investigated, and a phenomenon of periodic oscillation with small amplitude is observed. Meanwhile, a new variable smoothing length is presented to remove the unstable phenomenon and a new surface tension technique is adopted in the simulation. Subsequently, the phenomenon of periodic oscillation of a van der Waals model liquid drop is simulated using KGC-SPH method, in which the influence of the elongation and Reynolds number on the amplitude and oscillation period is discussed.
Numerical simulation of bubbles coupled with an elastic membrane
Authors: Wang Shi-Ping  , Zhang A-Man  , Liu Yun-Long  , Yao Xiong-Liang  ,   College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China
Published: December 2020

Based on the previous studies, the numerical model of oscillating bubble coupling with elastic membrane is built under the consideration of buoyancy, surface tension and different fluid density ratios. Provided that the fluid around bubble is incompressible the boundary element method is adopted to solve this model and the numerical results coincide well with the Turangan’s experimental results. Through the numerical simulation of the oscillating bubble near elastic membrane, the characteristics of bubble are discussed in fluids of the same density or different densityies separated by the elastic membrane, together with the jet features under the combination of elastic membrane and buoyancy. All these work is to present references to the research on dynamic behavior of bubble near elastic membrane.
Transverse dispersion laws in ultra-relativistic plasma with fast electron distribution
Authors: Liu San-Qiu  , Guo Hong-Mei  ,   Department of Physics, Nanchang University, Nanchang 330031, China
Published: December 2020

Analytic and numerical study of electromagnetic oscillations of isotropic relativistic plasma with fast electron distribution is presented. Different analytic formulas for the long-wavelength and short-wavelength branches are obtained. The numerical study gives the dispersion curve in the whole wavenumber range. It is shown that analytical dispersion curves in the long-wavelength and short-wavelength regions are coincident with the numerical ones. Furthermore, the approximate expression of the dispersion law for the different parameters is given by fitting numerical curves with the polynomial regression method, which provides a reference for further study.
Design of implosion capsules with low convergence ratio driven by radiation on Shenguang Ⅱ and Shenguang Ⅲ prototype laser facilities
Authors: Jiang Shao-En  , Miao Wen-Yong  , Kuang Long-Yu  ,   Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900,China
Published: December 2020

The design method for implosion capsules with low convergence ratio driven by radiation was dweloped. These kinds of the capsules used for the experiment on Shenguang II (SG-II) and Shenguang III prototype (SG-III-P) laser facilities were simulated using Multi-1d code. The implosion targets were designed, and the variations of convergence ratio, neutron yield and area density vs fuel pressure were obtained from the simulation. Two kinds of implosion targets with low convergence ratio on SG-II which were filled with DD and DT fuels respectively and a kind of the target on SG-III-P filled with DD were designed. The neutron yield calculated by Multi-1d with low convergence ratio agreed with the experimental data on Shenguang II laser facility. It showed that Multi-1d is reliable for use with these experiments.
Quantitative study of radiation temperature for gold hohlraum on SG-Ⅱ laser facility
Authors: Li San-Wei  , Song Tian-Ming  , Yi Rong-Qing  , Cui Yan-Li  , Jiang Xiao-Hua  , Wang Zhe-Bin  , Yang Jia-Min  , Jiang Shao-En  ,   Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Hohlraum radiation temperature is an important parameter for inertial confinement fusion (ICF) research. Experimental measurements of radiation temperature by a streaked optical pyrometer and a soft X-ray spectrometer (SXS) with 14 absolutely calibrated channels are performed on SG-Ⅱ laser facility,which shows that the results of the two methods agrees with each other well. With 2.1kJ laser energy and 1ns pulse width, the hohlraum radiation temperatures for small hohlraum (Φ0.8 mm×1.7 mm, LEHΦ0.38 mm) and large hohlraum (Φ1.0 mm×2.1 mm, LEHΦ0.6 mm) are 180 eV and 150 eV, respectively. Using a sampling-based method (Monte Carlo), an uncertainty analysis program-package is set-up for SXS. After precise calibration and improvements for several components in SXS, the relative uncertainty of radiation temperature is significantly reduced from 8% to 3%.
Analsys of the properties of tunable prohibited band gaps for two-dimensional unmagnetized plasma photonic crystals under TM mode
Authors: Zhang Hai-Feng  , Liu Shao-Bin  , Kong Xiang  ,   (1)College of Information Science & Technology, Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China; (2)College of Information Science & Technology, Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China; Nanjing Branch , Artillery Academy, Nanjing 211132, China; (3)College of Information Science & Technology, Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China; Zhenjiang Watercraft College , Zhengjiang 212003, China
Published: December 2020

The piecewise linear current density recursive convolution (PLCDRC) on finite-difference time-domain (FDTD) method is applied to study the properties of prohibited band gaps for TM wave propagation in the two-dimensional unmagnetized plasma photonic crystal. In frequency-domain, the transmission coefficient of electromagnetic differential Gaussian pulses are computed and we analyzed the effect on properties of tunable prohibited band gaps for the two-dimensional unmagnetized plasma photonic crystals by its relative permittivity of column, lattic constant, dielectric column radius, periodic constant and parameters of plasma. The results showed that the prohibited band gaps can not be broadened by inceasing periodic constant and plasma collision frequency, but can be broadened by increasing relative permittivity of column and plasma frequency. The prohibited gaps also can be widened by decreasing the lattic constant and dielectric column radius for fill rate of a certain value.