bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation study on the design of key technical parameters in marine environment sounding with fully polarimetric synthetic aperture radar based on ocean surface scattering model
Authors: Zhao Xian-Bin  , Yan Wei  , Wang Ying-Qiang  , Lu Wen  , Ma Shuo  ,   College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing 211101, China
Published: December 2020

Technical parameter design is an effective approach to improve marine environment sounding capability for fully polarimetric synthetie apertuer radar (SAR). By analyzing geophysical contact between noise-equated backscattering coefficient and marine environment sounding, and that between radiometric resolution and marine environment sounding, we present the key technical parameters design method for fully polarimetric SAR. We first calculate radar backscattering coefficient in different marine environments by using the fully polarimetric ocean surface scattering model, and accordingly determine the noise-equated backscattering coefficient of fully polarimetric SAR ocean sounding. Then the noise-equated backscattering coefficient is used as an input parameter in SAR equation, and the function relationship between radiometric resolution and signal to noise ratio is used as a constraint condition, we thus can carry out technical parameter design, such as for signal to noise ratio, radiometric resolution and system power aperture product. By simulation calculation of fully polarimetric ocean surface scattering, we find that the noise-equated backscattering coefficient of ocean sounding is designed to -35.0 dB, which can meet the needs of fully polarimetric SAR sounding in different marine environments. Studying the function relationship between radiometric resolution and signal to noise ratio, we find that the optimal signal to noise ratio of ocean sounding is 8.0 dB. Results of C-band airborne fully polarimetric SAR design show that the above method can make technical parameter of fully polarimetric SAR meet both the need for marine environment application and system design, because of taking into account the needs of marine environment sounding.
A new method for the pulsar signals simulation
Authors: Bei Xiao-Min  , Shuai Ping  , Huang Liang-Wei  , Sun Hai-Feng  , Wu Yao-Jun  , Zhang Qian  ,   Qian Xuesen Laboratory of Space Technology, Beijing 100094, China;,   School of Electronic Engineering, Xidian University, Xi'an 710071, China
Published: December 2020

Since X-ray pulsar signals cannot be detected on the ground, the pulsar signals need be simulated using the ground experiments. In this paper,two new simulation methods to obtain the time of arrival are put forward. The first method is based on a statistical physics model, which should overcome the shortcomings of narrow adaptation, low speed, and low time resolution in normal simulation method. This method has a high time-resolution and rapid simulation for any random pulse signals. 23 Another one is for the optimization of statistical models that satisfy signals in non-homogeneous Poisson process. The is second method has an improved simulation speed at least 30 times higher than the common Poisson model, even achieves four orders of magnitude greater than that for low flow pulsars, and this method also achieves a nanosecond time resolution simulation.
Study on stability control mechanism of multiple unmanned aerial vehicle cooperative system
Authors: Ru Chang-Jian  , Wei Rui-Xuan  , Shen Dong  ,   Institute of Aeronatics and Astronautics Engineering, Air Force Engineering University, Xian 710038, China;,   No. 94795 Army of PLA, Wuhu 241000, China
Published: December 2020

The excessive diffusion of multiple unmanned aerial vehicle (UAV) cooperative system may lead to the cooperative failure, but to control the system scale is a potential way to solve this problem. First, macroscopic motion characteristic of multi-UAV cooperative searching system is abstracted, and then motion model of the platform is established. Afterwards, by constructing an appropriate Lyapunov function, the stable control mechanism of this system and its stable control parameters are obtained. Simulation results verify the following two conclusions: 1) the proposed stable control mechanism can not only make multi-UAV system realizes the effective cooperation, but also can ensure the stability of this system; 2) when this system is in a stable state, its scale can be controlled effectively by adjusting the relevant control parameters.
Decompositions of beam splitter operator and its entanglement function
Authors: Jia Fang  , Xu Xue-Xiang  , Liu Cun-Jin  , Huang Jie-Hui  , Hu Li-Yun  , Fan Hong-Yi  ,   Department of Material Science and Engineering, University of Science and Technology of China, Hefei 230026, China;,   Key Laboratory of Optoelectronic and Telecommunication, Jiangxi Normal University, Nanchang 330022, China
Published: December 2020

Beam splitter (BS) is a basic linear element in quantum optics, which plays an important role in preparation of entangled states and quantum measurement. On the basis of the transformation relation between operators at input ports and output ports, we derive the natural representations in different representations. Using the natural expression rather than SU(2) Lie algebra relation, as well as the technique of integration within ordered product (IWOP) of operator, we can conveniently and concisely derive the normally ordering form and exponential expression of BS operator. Many forms of decompositions for BS operator can also be directly obtained by its natural representation and the orthogonality of coordinate states. Furthermore, the entangled state representation and corresponding Schmidt decomposition can be conveniently obtained.
Stabilization of matter-wave solitons in Bessel optical lattice by spatial modulation of the nonlinearity
Authors: Chen Hai-Jun  , Zhang Yao-Wen  ,   Electrical Engineering College, Longdong University, Qingyang 745000, China
Published: December 2020

Using variational and numerical solutions of the mean field Gross-Pitaevskii equation, we investigate the stabilities of nonrotating and vortex solitons in Bessel optical lattice by spatial modulation of the nonlinearity(nonlinear optical lattice). It is demonstrated that there exist the stable matter-wave solitons in a combination of optical lattices with linear Bessel optical lattices and nonlinear optical lattice. Using the time-dependent variational approach, we derive the odinary differential equations for the time evolutions of the width and phase of solitons. Through an effective potential, we obtain the stable criteria for all kinds of combinations of the system parameters. We perform direct numerical simulations to support our analytical results, and find that they are in goog agreement.
A cascading failure model of complex network with hierarchy structure
Authors: Yuan Ming  ,   Department of Statistics, Tianjin University of Finance and Economic, Tianjin 300222, China
Published: December 2020

In this paper, we proposes a cascading failure model for the complex network with hierarchy structure which is common in real networks. This model can be used to optimize the financial or logistic network design. The hierarchy network has a tree-shape backbone and many random hidden linkages. The branches of each node in the backbone follow normal distribution. The attack on the network is from bottom layer under the condition of incomplete information, i.e., on the assumption that the attacker cannot observe the hidden linkages. The load redistribution of the failure nodes takes into consideration the hierarchy heterogeneity, of which the network tends to redistribute extra load to intact nodes of the same or higher hierarchies. Simulation experiment shows that the topology of hierarchy network changes from small world network into random network with the variation of linkage parameters. The size of cascading failure firstly increases and then decreases with the hidden linkage ratio increasing and the network shows higher robustness when the load of failure node is redistributed to the intact node with high hierarchy. The experiments also demonstrate that the linkage parameters play a significant role in the robustness of the network because these parameters can affect the hierarchy distribution of hidden links. Therefore, in order to achieve better robustness of network, we should reasonably choose parameters in topology design and network control strategies.
Coherence resonance of piezoelectric energy harvester with fractional damping
Authors: Li Hai-Tao  , Qin Wei-Yang  , Zhou Zhi-Yong  , Lan Chun-Bo  ,   Department of Engineering Mechanics, Northwestern Polytechnical University, Xi'an, 710072 China
Published: December 2020

In this paper, we investigate the coherence resonance of a piezoelectric energy harvester of beam subjected to an axial force. The fractional damping is considered. First, a nonlinear model of the energy harvesting system with fractional damping and random excitation is set up. The coupling equations of dynamics and electrics are derived. Euler- Maruyama-Leipnik method is used to solve the fractional order differential equations. The signal-to-noise ratios, mean responses, and other statistical quantities under the damping forces with different orders are computed. The results obviously show the appearance of coherence resonance. It can be seen that the reduction of fractional order not only reduces the critical value of noise level, thus leading to coherence resonance, but also increases the amplitude on the occurrence of coherence resonance. So it is possible to maximize harvest power for a given density or variance of random excitation by varying system parameters.
Dispersion characteristics of the coaxial interlaced disk-loaded waveguide slow-wave structure
Authors: Wang Bing  , Wen Guang-Jun  , Wang Wen-Xiang  ,   School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China;,   School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

The dispersion equation of the coaxial interlaced disk-loaded waveguide slow-wave structure is derived by the multi-conductor transmission line method. The simulation results by HFSS are in good agreement with the calculation results obtained from the dispersion equation. Influences of structure parameters on dispersion characteristics are discussed. It can be concluded that with the increase of inner conductor and the decrease of the period length, the bandwidth of the slow-wave structure becomes greater. The dispersion characteristics of the coaxial interlaced disk-loaded waveguide and those of the coaxial disk-loaded waveguide are compared. The results show that the coaxial interlaced disk-loaded structure can obtain a wide bandwidth and weak dispersion. This study will be a guide to the research of the coaxial interlaced disk-loaded waveguide slow wave structure used in the traveling-wave tube.
Dark-field digital holographic microscopy by using vortex beam illumination
Authors: Zhao Ying-Chun  , Zhang Xiu-Ying  , Yuan Cao-Jin  , Nie Shou-Ping  , Zhu Zhu-Qing  , Wang Lin  , Li Yang  , Gong Li-Ping  , Feng Shao-Tong  ,   Key Laboratory for Opto-Electronic Technology of Jiangsu Province, Nanjing Normal University, Nanjing 210023, China
Published: December 2020

We propose a dark-field digital holographic microscopy (DHM) by using vortex beam illumination. In this paper, the annular illumination of vortex beam and the dark-field DHM imaging system are theoretically analyzed, and the quasi-nondiffracting property of the vortex beam is discussed. A corresponding DHM imaging system is established. The polystyrene spheres each with a size of 690 nm are utilized as objects in the experiment. By comparing the results of reconstructed images under bright-field illumination with those under dark-field illumination DHM, it is proved that the resolution of dark-field DHM under speckle-field illumination is improved and the contrast of its reconstructed image is enhanced accordingly.
Wind velocity retrieval and field widening techniques of fringe-imaging Mach-Zehnder interferometer for Doppler lidar
Authors: Tan Lin-Qiu  , Hua Deng-Xin  , Wang Li  , Gao Fei  , Di Hui-Ge  ,   School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, Xi'an 710048, China
Published: December 2020

Compared with the traditional Doppler frequency discriminator Fabry-Perot interferometer, Mach-Zehnder interferometer (MZI) has the advantages in high transmittance, linear parallel fringes instead of circular rings and wide field of view. An incoherent Doppler wind lidar system is demonstrated based on a fringe-imaging MZI. The mathematical model of wind velocity retrieval is derived, and the field widening of MZI is also used to optimize the performance of lidar system. The ideal fringe pattern outputs are obtained by numerical simulation, and the SineSqr function fitting method is proposed to determine the high-precision displacement of fringes after a Doppler shift. Furthermore, the field widening of MZI can be realized by field compensation which reduces the effect of the incidence angle on optical path difference. The results show that the wind velocity error obtained by SineSqr function fitting method is less than 0.45 m·s-1 at the line-of-sight wind velocity in a range from -100 m·s-1 to 100 m·s-1, which overcomes the instability of wind velocity retrieval by the gravity method. A full-angle field of view of 1° for MZI frequency discriminator without significant performance reduction is also achieved. These supplied discussion of the application techniques for Doppler lidar based on MZI fringe technique would promote the practical development of Doppler lidar for wind velocity measurement of the middle and upper atmosphere.
Band gap attenuation characteristics of periodic compound plate with wave propagation approach
Authors: Zhang Jun-Jie  ,   National Key Laboratory on Ship Vibration and Noise, China Ship Development and Design Center, Wuhan 430064, China
Published: December 2020

The band gap attenuation characteristics of finite and infinite periodic compound plate simply supported along its longitudinal edges are investigated with the wave propagation approach. Base on the boundary continuum condition between two plates, the coupled equations of finite and infinite periodic compound plate are established by transfer matrix and Bloch theorem respectively, and the relations of band gap attenuation characteristics between finite and infinite periodic compound plate are analyzed in detail. It is shown that the frequency band gap of periodic compound plate is related to exciting form and position. The frequency band gap of finite compound plate is coincident with the frequency band gap of infinite compound plate with the same mode vibration if finite compound plate is excited with one mode along its longitudinal edges. If the plate is excited with a point force, the frequency band gap is the intersection of frequency band gap of all participated modes. Besides, the influence of the structural damping on band gap is also analyzed.
Comparisons among weakly-compressible and incompressible smoothed particle hdrodynamic algorithms for natural convection
Authors: Lei Juan-Mian  , Yang Hao  , Huang Can  ,   Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

Smoothed particle hydrodynamic (SPH) method is used to solve a variety of complex engineering problems. In the literature about SPH, there are two approaches to solving the pressure component of momentum conservation equation, namely incompressible SPH (ISPH) and weakly compressible SPH (WCSPH) methods. In this paper, we present a new comparative study of WCSPH (Lagrange), ISPH (Lagrange) and ISPH (Euler) methods, focusing on heat conduction issue by numerical solutions of natural convection in a square cavity. Temperature distributions, velocity distributions and Nusselt number distributions at different Rayleigh numbers (Ra=104, 105, 106) are provided in the paper. The quantitative comparisons of results show that WCSPH (Lagrange), ISPH (Lagrange) and ISPH (Euler) methods all perform very well at low Rayleigh number. And at high Rayleigh number, SPH (Lagrange) needs shifting particle technology to correct the distribution of particles, ISPH (Euler) performs best because of the motionless particles, WCSPH (Lagrange) performs better than ISPH (Lagrange).
Radiation effect of deep-submicron metal-oxide-semiconductor field-effect transistor and parasitic transistor
Authors: Wang Xin  , Lu Wu  , Wu Xue  , Ma Wu-Ying  , Cui Jiang-Wei  , Liu Mo-Han  , Jiang Ke  ,   Key Laboratory of Functional Materials and Devices for Special Environments, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China;,   Xinjiang Key Laboratory of Electronic Information Material and Device, Urumqi 830011, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

The metal-oxide-semiconductor field-effect transistor (MOSFET) and the parasitic bipolar transistor of domestic complementary metal oxide semiconductor (CMOS) process are irradiated with 60Coγ rays to investigate the failure mechanism of the mixed-signal ICs fabricated by deep submicron CMOS process, caused by total dose radiation. The research results are as follows. 1) The parasitic sidewall and top corner regions contribute to the intra-device leakage. 2) The parasitic bipolar transistor of CMOS process is not sensitive to total dose radiation, which is very different from the conventional bipolar transistor. Preliminary analysis suggests that the difference originates from the differences in the structural and making process. 3) The total dose radiation damage to the parasitic bipolar transistors is not coupled with the damage to the NMOS transistor in the same CMOS process. 4) Based on the above study, the radiation failure mechanisms of the analog and digital module in mixed-signal ICs fabricated respectively by the domestic and commercial CMOS process are investigated. Preliminary analysis suggests that the increase of off-leakage current of MOSFET is responsible mainly for the increase in power consumption of digital module, and the insensitivity of bandgap voltage reference to total dose radiation originates from the radiation resistance of the parasitic bipolar transistor which is the important part of bandgap voltage reference in CMOS mixed-signal ICs.
First principles investigation of interaction between interstitial hydrogen atom and Fe metal
Authors: Zhang Feng-Chun  , Li Chun-Fu  , Wen Ping  , Luo Qiang  , Ran Zeng-Ling  ,   State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China;,   College of Science, Southwest Petroleum University, Chengdu 610500, China;,   Key Laboratory of Optical Fiber Sensing and Communication of the Ministry of Education, University of Electronics Science and Technology of China, Chengdu 611731, China
Published: December 2020

In this paper, the site occupations of H under different mole ratios in interstitials of α -Fe and γ -Fe are studied by the first principles method based on the density functional theory. The total energy of the steady state crystal, binding energy, solution heat, density of states, charge density difference and charge population are calculated. The interaction between interstitial H and Fe lattice is analyzed. The influences of hydrogen dissolution on electronic structure of α -Fe and γ -Fe are discussed. The results show that the dissolved hydrogen leads to the lattice distortions of α -Fe and γ -Fe, and the volume expansion ratio increases with the dissolved quantity of hydrogen increasing. The energy analysis indicates that the hydrogen preferentially occupies the tetrahedral interstitial of α -Fe, while in the γ-Fe it preferentially occupies the octahedral interstitial. The analyses of density state, charge density difference and charge population reveal that the interaction between interstitial hydrogen and Fe lattice is contributed by the H 1s orbital and Fe 4s orbital, and this interaction is relatively weak, which is one of the main reasons for lower solid solubility of hydrogen in Fe lattice.
New REBULF super junction LDMOS with the N type buffered layer
Authors: Duan Bao-Xing  , Cao Zhen  , Yuan Xiao-Ning  , Yang Yin-Tang  ,   Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China
Published: December 2020

In this paper, a new REBULF (reduced BULk field) SJ-LDMOS (lateral double-diffused MOSFET) is proposed with the N type buffered layer based on the buffered SJ-LDMOS for the low loss of LDMOS used in the power integrated circuits. In this structure, the problem of the substrate-assisted depletion, produced due to the P-type substrate for the N-channel SJ-LDMOS, is eliminated by the N-type buffered layer. The charges for the N-type and P-type pillars are depleted completely. Moreover, a new electric field peak is introduced into the surface electric field distribution, which makes the lateral surface electric field uniform. The breakdown voltage is improved for the REBULF SJ-LDMOS in virtue of the ISE simulation results. By optimizing the location and parameters of the N-type buried layer, the breakdown voltage of REBULF SJ-LDMOS is increased by about 49% compared with that of the conventional LDMOS, and improved by about 30% compared with that of the buffered SJ-LDMOS.
A real-time magnetic localization method of underwater non-cooperative magnetic targets based on unscented particle filter
Authors: Yao Zhen-Ning  , Liu Da-Ming  , Liu Sheng-Dao  , Zhu Xing-Le  ,   College of Electrical Engineering, Naval University of Engineering, Wuhan 430033, China
Published: December 2020

A real-time magnetic localization method based on unscented particle filter (UPF) is proposed to solve the problem for real-time localization of underwater non-cooperative magnetic targets. The state space model of non-cooperative magnetic targets is set up according to its motion characteristic, and the state is estimated in real time by UPF. In order to improve the observability of the system, the particle state is constrained and magnetic moment is inverted by the least square method. The simulation results and ferromagnetic object localization experimental results show that the method is good in localization precision and real-time performance, which can be applied to the real-time magnetic localization in near field.
Suppression effect of periodic semicircle groove disk on multipactor
Authors: Zhang Xue  , Fan Jun-Jie  , Wang Yong  ,   Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China;,   University of Chinese Academy of Sciences, Beijing 100149, China
Published: December 2020

In this paper, the periodic semicircle groove disk is investigated to restrain the multipactor phenomenon in high power pill-box window. Through the theoretical analysis, the semicircle groove is proved to avoid the local field enhancement, which always exists in the vicinity of the sharp boundary groove. The proper groove width with a corresponding minimal suppression tangential electric field is achieved by simulating the multipactor procedure with Monte-Carlo algorithm. The effect of normal electric field is also analyzed. This configuration is to be applied to the high power klystron.
Measurement uncertainty of metallic ductility in tensile tests: intermediate temperature embrittlement and strain rate embrittlement
Authors: Xu Ting-Dong  , Liu Zhen-Jun  , Yu Hong-Yao  , Wang Kai  ,   High Temperature Materials Research Institute, Central Iron and Steel Research Institute, Beijing 100081, China
Published: December 2020

International Standard, ISO 6892-2, Metallic Materials-Tensile Testing: Method of Test at Elevated Temperature maintained that the strain rate variations and test temperature variations can induce the measurement uncertainty of mechanical properties in tensile testing, which will imperil the reliability of tension tests. In this paper, the measurement uncertainties of shrinkage rate or elongation rate in tensile testing cross-section, intermediate temperature embrittlement and strain rate embrittlement are first described experimentally. Second, the fundamental results on the microscopic theory of elastic deformation in metals are briefly mentioned. Then the phenomena of the measurement uncertainties are explained based on the microscopic theory. It is expounded that the elastic deformation of tension tests induces the impurities to segregate to grain boundaries and the relative embrittlement which produces the measurement uncertainties of reduction in area. This work gives a theoretical basis for correcting the present standard method of tension testing to avoid the measurement uncertainty of reduction in area.
Multi-channel magnetocardiogardiography system calibration
Authors: Zhang Yong-Sheng  , Qiu Yang  , Zhang Chao-Xiang  , Li Hua  , Zhang Shu-Lin  , Wang Yong-Liang  , Xu Xiao-Feng  , Ding Hong-Sheng  , Kong Xiang-Yan  ,   Department of Physics, University of Science and Technology, Beijing 100083, China;,   State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
Published: December 2020

The field-to-voltage transfer coefficient (∂ B/∂ V) is an important parameter of the multi-channel superconducting quantum interference device (SQUID) magnetic detecting system. The SQUID devices and the readout circuits have the inevitable differences among different channels, so the accurate calibration of system channels is rather significant. In this paper, We first used the circular PCB coils for 36-channel MCG system calibration, and the other one is based on a traditional method in which a uniform field is produced by square Helmholtz coil. The calibration data show that the results are basically the same. The calibrated ∂ B/∂ V values using circular PCB coils are in a range from 1.46-1.73 pT·mV-1. And those of square Helmholtz coils are mostly within a range from 1.56-1.64 pT·mV-1.
Multi-channel wide area adaptive damping control for suppressing low-frequency and sub-synchronous oscillation
Authors: Zeng Guo  , Li Xing-Yuan  , Liu Tian-Qi  , Zhao Rui  ,   School of Electrical Engineering and Information, Sichuan University, Chengdu 610065, China;,   Electric Power Research Institute, China Southern Power Grid, Guangzhou 510080, China
Published: December 2020

A model reference adaptive control scheme is developed based on hyper-stability theory and is proved. Both of reduced order models of the power system and relevant oscillation frequencies are acquired by TLS-ESPRIT algorithm. The band-pass filters (Butterworth) are utilized to decompose oscillation frequencies into different channels and controllers are designed for each oscillation mode based on adaptive control method, thus reducing the influences of the various controllers. Xiangjiaba-Shanghai DC link under island operation condition is simulated using electromagnetic transient program PSCAD/EMTDC to demonstrate proposed control strategy. The results validate that the proposed method is able to suppress low-frequency oscillation and sub-synchronous oscillation simultaneously and the proposed method has better control performance than the traditional PID control. The problem will lead to controller performance deterioration caused signal transmission delay in system and it is resolved by phase compensation.
On dynamic information theory
Authors: Xing Xiu-San  ,   Department of Physics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

In this paper, the author presents an overview on his own research works. In recent ten years, we extended the present static statistical information theory to dynamic processes and established a dynamic statistical information theory whose core is the dynamic information evolution equation describing the evolution law of dynamic information. Starting from the idea that the state variable probability density evolution equations of the stochastic dynamic system, the classical and quantum nonequilibrium statistical physical systems obeying stochastic law and the electrodynamic system obeying decterministic law can be regarded as their information symbol evolution equations and the definitions of dynamic information and dynamic entropy, we derived the evolution equations of dynamic information and dynamic entropy that express the evolution laws of dynamic information. These show that for the dynamic systems obeying a stochastic law, the time rate of change of dynamic information densities originates from their drift, diffusion and dissipation in state variable space inside the systems and coordinate space in the transmission processes, and that the time rate of change of dynamic entropy densities is caused by their drift, diffusion and production in state variable space inside the systems and coordinate space in the transmission processes. For the dynamic systems obeying the deterministic law, the evolution equations of dynamic information and dynamic entropy are the same mathematical type as the former except that dynamic information (entropy) density only has drift in state variable space inside the systems. Information and entropy have been connected with the state and change law of the system. Information diffusion and information dissipation occur at the same time. When the space noise can be neglected, information wave will appear. If we only consider the information change inside the systems, the dynamic information evolution equations reduce to information equations corresponding to the dynamic equations which express evolution laws for the above dynamic systems. This reveals that the evolution laws of the respective dynamic systems can be expressed by information equations in a unified fashion. Furthermore, we have presented the formulas for drift and diffusion information flow, information dissipation rate, and entropy production rate and a unified information expression for degradation and self-organizing evolution. Obtained the dynamic mutual information and dynamic channel capacity reflecting the dynamic dissipative character in transmission process, in when in the limiting case the ratio of channel length to signal transmission rate approaches zero, reduces itself to the present static mutual information and static channel capacity. All these new theoritical formulas and results are derived from the dynamic information evolution equation.
Synchronization control for a class of tele-operation system with stochastically time-varying communication delays
Authors: Cui Jun-Hui  , Wei Rui-Xuan  , Qi Xiao-Ming  ,   Unmanned Aerial Vehicle Application Engineering Department, Air Force Engineering University, Xi'an 710038, China;,   69220 People's Liberation Army Troops, Aksu 842000, China
Published: December 2020

Synchronization control methods for a class of tele-operation system with stochastically time-varying communication delays are surveyed, aiming at the existing communication delays, packet loss, and so on, during the ground-based tele-operation of unmanned aerial vehicles. A control model for this class of master-slave tele-operation system with communication time delays is established. Then, the time delays within the remote control communication network are depicted by a time-varying-delay function, of which the modal parameters are transferred based on an ergodic Markov process. After that, the synchronization control problem of the system is solved by stability analysis of the mean square within the framework of the stochastic systems. Finally, the semi-physical simulation platforms of an unmanned micro-quadrotor are carried out to verify the methods presented in this paper; and the elementary simulation results show that the loci of the master-slave sides are all bounded through designing the controllers by the feedback linearization separately in the methods.
Research on synchronous method for photovoltaic supplied micro-grid based on small-world network model
Authors: Liao Zhi-Xian  , Luo Xiao-Shu  ,   College of Electronic Engineering, Guangxi Normal University, Guilin 541004, China
Published: December 2020

Based on the solution to the strictly piecewise linear state equation of a photovoltaic (PV) supplied micro-grid inverter, the nonlinear dynamic behavior of PV supplied micro-grid inverter is analyzed in this paper, and each PV supplied micro-grid inverter is considered as a network node, then a synchronous method for PV supplied micro-grid is studied using the small-world network model. Studies have found that, compared with the nearest-neighbor coupling network model, the PV supplied micro-grid based on the small-world network model has a faster synchronization time, and also has a faster recovery time in case of plus disturbance.
Analysis on spherical conformal microstrip antenna array by characteristic basis function method
Authors: Yu Tao  , Yin Cheng-You  , Liu Han  ,   State Key Laboratory of Pulsed Power Laser Technology, Institute of Electronic Engineering, Hefei 230037, China
Published: December 2020

Spherical conformal microstrip antenna array which is used widely in the field of aeronautics is analyzed by the full wave analysis in this paper. Using the surface integral equation with spherical dyadic Green's function can decrease the number of unknowns remarkably, and also reduce the demand of memory as compared with the method using volume-surface integral equation. The curvilinear triangle is proposed to mesh the surface of the microstrip antenna array, which can simulate the characteristic of spherical surface accurately. Firstly, the problem about probe feed model is solved successfully by introducing the half Rao-Wilton-Glisson function and boundary charge, and the image method is used to treat the line integral singularity problem. Then, the characteristic basis function method is employed to further save memory and computation time further by reducing the rank of impedance matrix. Finally, the input impedance and far-field spherical conformal microstrip antenna array of different sizes are analyzed. Results are in good agreement with those in the literature and simulation software, and thus the validity and effectiveness of the analysis method are demonstrated.
Isotope effect of trihydride aluminum oxide
Authors: Ren Gui-Ming  , Zheng Yuan-Yuan  , Wang Ding  , Wang Lin  , Chen Xiao-Hong  , Wang Ling  , Ma Min  , Liu Hua-Bing  ,   School of Physics-Chemistry, Xihua University, Chengdu 610039, China;,   Research Center for Advanced Computation, Xihua University, Chengdu 610039, China
Published: December 2020

The lower energy structures of Al2O3H3 molecular clusters are optimized through DFT/B3LYP connected with 6-311g++(d, p) all electrons basis set. It is found that the ground state configuration of Al2O3H3 has 1A' electronic state and Cs symmetry. Based on the research on energy, heat capacity at constant volume, entropy of Al2O3M3 and M2 (M=H, D, T), the hydrogen isotope effects of reactions between Al2O3 and hydrogen (deuterium or tritium) gas are studied by means of the solid electron-vibration approximation. In addition, the changes of enthalpy, entropy and Gibbs free energy, and the relation between equilibrium pressures and temperatures are presented. The investigation suggests that hydrogen can be replaced by deuterium, and deuterium can be replaced by tritium in the reactions between Al2O3 and M2 with the productions of solid Al2O3M3 (M=H, D, T). This replacement sequence is opposite to the metallic isotope effect e. g. for titanium, however these replacement effects are very weak, and they are weaker and weaker as the temperature increases.
Study on the photodetachment of H- ion near a dielectric sphere
Authors: Chen Qiang  , Wang De-Hua  ,   School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China
Published: December 2020

Photodetachment of hydrogen negative ion near a dielectric sphere has been studied by using the image method combined with the semiclassical closed orbit theory. Firstly, we analyze the image charge distribution of the detached electron near the dielectric sphere; then we put forward the Hamiltonian for this system. By solving the Hamiltonian canonical equations, we can find the closed orbits of the detached electrons moving near the dielectric sphere. With the help of the semiclassical closed orbit theory, we derive the formula for calculating the photodetachment cross section of this system. Then we can calculate and analyze the photodetachment cross section. Calculated results suggest that the photodetachment cross section of the hydrogen negative ion near a dielectric sphere is not only related to the photon energy, but also the dielectric constant of the sphere. For a given dielectric sphere, with the increase of photon energy, the oscillating amplitude in the photodetachment cross section decreases while the oscillation frequency increases. When the photon energy is increased to a critical value, the oscillating structures in the cross section disappear. In addition, with the increase in the dielectric constant of the dielectric sphere, the oscillating structure in the photodetachment cross section becomes much more complicated. When the dielectric constant is increased to infinity, the photodetachment cross section of this system is consistent with the photodetachment cross section of the hydrogen negative ion near a metal sphere. Therefore, we can control the photodetachment cross section of the hydrogen negative ion near a dielectric sphere by changing the photon energy and the dielectric constant. Our study may provide some theoretical guidance and reference values for the experimental research of photodetachment of negative ion near the dielectric sphere.
Formulation for shielding effectiveness analysis of a rectangular enclosure with an electrically large aperture
Authors: Zhang Ya-Pu  , Da Xin-Yu  , Zhu Yang-Kun  , Zhao Meng  ,   Information and Navigation College, Air Force Engineering University, Xi'an 710077, China
Published: December 2020

Since electric components and printed circuit board in the enclosure can be destroyed by electromagnetic pulse weapons through “front door and back door” coupling, which is a great threat to the operational security, the study of the shielding effectiveness is of important significance. A formulation for shielding effectiveness analysis of a rectangular enclosure with an electrically large aperture is proposed in this paper. Firstly, the plane wave with oblique incidence and polarization is decomposed. Secondly, based on the Cohn model, the equivalent electric and magnetic dipole of the electrically large aperture is computed. Thirdly, the total Hertz electric and magnetic vector potential is obtained through mirror procedure. Finally, the electric field inside an enclosure with electrically large aperture is formulated, which is used for shielding effectiveness calculation. Five verification experiments are designed. Simulation result shows that the mean square error and absolute error of this method compared to computer simulation technology (CST) microwave studio are 11.565 dB and 8.015 dB respectively, the correlation coefficient is 0.921, through which the accuracy of this method is verified. The simulation time of this method is 0.183 s, which is only 1/7530 times of CST, so its efficiency is obvious.
Characterization of plasma in a short-tube helicon source
Authors: Zhao Gao  , Xiong Yu-Qing  , Ma Chao  , Liu Zhong-Wei  , Chen Qiang  ,   Laboratory of Plasma Physics and Materials, Beijing Institute of Graphic Communication, Beijing 102600, China;,   Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000, China
Published: December 2020

Characteristics of helicon plasma in a 45 cm long discharge tube were diagnosed by the Langmuir electrostatic probe, optical emission spectroscopy (OES), and integrated capacitively coupled detector (ICCD). The discharge in helical wave mode was confirmed by the sharply variation of electron density and electron temperature based on the Langmuir data. We have noticed that the variation of electron density measured by the Langmuir electrostatic-probe is consistent with the OES measurement. Intensities in the spectra of argon atoms and ions are strongly related to discharge modes. The photos taken by ICCD can distinguish the discharge modes in the radial region. Intensity changes in the radial region reflect the electron motivation and the energy transfer path in the helicon plasma.
Experimental investigation on the influence of the dopant ratio on ablative Rayleigh-Taylor instability growth
Authors: Yuan Yong-Teng  , Wang Li-Feng  , Tu Shao-Yong  , Wu Jun-Feng  , Cao Zhu-Rong  , Zhan Xia-Yu  , Ye Wen-Hua  , Liu Shen-Ye  , Jiang Shao-En  , Ding Yong-Kun  , Miao Wen-Yong  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China;,   Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

Ablative Rayleigh-Taylor growth was measured with single-mode modulated planar CH foil with different ratio of Br dopant at Shenguang Ⅱ laser facility. Results show that CH (6% Br) sample first enters the nonlinear regime and has the largest perturbation amplitude of second harmonic. The reason is that the density gradient effects can suppress the generation of the second harmonic, the more the Br is doped, the smaller the density gradient scale length can be achieved. The density gradient effects also suppress the feedback of third-order harmonic to the fundamental mode, which induces the nonlinear saturation amplitude to exceed 0.1λ, as the classical prediction shows.
Laser shadowgraphy diagnostics for insulated-ordinary mixed planar wire array Z pinches
Authors: Sheng Liang  , Peng Bo-Dong  , Yuan Yuan  , Zhang Mei  , Li Kui-Nian  , Zhang Xin-Jun  , Zhao Chen  , Zhao Ji-Zhen  , Li Mo  , Wang Pei-Wei  , Li Yang  ,   State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi'an 710024, China
Published: December 2020

A laser shadowgraphy system was built based on a Nd:YAG laser backlight with a half width of 9 ns and a wavelength of 532 nm. It has the capacity of time resolution and integration simultaneously during the laser lighting time by utilizing a streak camera and a commercial digital camera as the image recording devices. Experimental study of the insulated-ordinary mixed planar wire array Z pinches was carried out on the Qiangguang-I facility. Experimental results indicate that the expansion of corona plasma of the insulated tungsten wires is slower than that of ordinary wires over the ablation stage. Average velocities of the insulated wire and the ordinary wire located at the array outmost edge are 1.1×104 m·s-1 and 1.7×104 m·s-1 between t=44 ns and t=56 ns respectively. In the fastest implosion stage of 10 ns just before the stagnant time, the average imploding velocities were 5.5×105 m·s-1 and 9.3×105 m·s-1 respectively for the plasma on the insulted wires side and the ordinary wires side. The duration of stagnant stage on the insulated wires side is 5.9 ns, while it is 9.5 ns on the ordinary wires side. The collision boundary is deflected to the insulated wires side. A similar magneto Rayleigh-Taylor Instability structure can be observed on the both sides at the stagnant time.
Molecular dynamics simulation on thermal conductivity of nanocomposites embedded with fractal structure
Authors: Zhang Cheng-Bin  , Cheng Qi-Kun  , Chen Yong-Ping  ,   Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China
Published: December 2020

Sierpinski carpet fractal structure is introduced into the construction of Si/Ge nanocomposites in this paper so as to regulate and control the thermal conductivity of the nanocomposites. Non-equilibrium molecular dynamics simulation is applied to investigate the thermal conduction performance of nanocomposites embedded with fractal structure. Effects of the silicon atom percent, axial length and cross-sectional dimensions on the thermal conductivity of nanocomposites embedded with fractal structure are analyzed and compared with the corresponding nanocomposites embedded with traditional rectangular structure. It is indicated that, owing to the enhanced scattering at the Si/Ge interfaces of nanocomposites embedded with fractal structure, their thermal conductivity are lower than that embedded with rectangular structure, thus providing an effective way to improve the thermoelectric efficiency. And it is also demonstrated that the thermal conductivity of nanocomposites embedded with fractal structure are affected by the silicon atoms percent, axial length and cross-sectional size. The thermal conductivity is first decreased and then increased with the increase of Si atom percent. In addition, the increase in axial length of nanocomposites may lead to the enhancement of thermal conduction.
Modeling on drain current of high-k gate dielectric fully-depleted nanoscale germanium-on-insulator p-channel metal-oxide-semiconductor field-effect transistor
Authors: Bai Yu-Rong  , Xu Jing-Ping  , Liu Lu  , Fan Min-Min  , Huang Yong  , Cheng Zhi-Xiang  ,   School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

An analytical model for drain current of high-k gate dielectric fully-depleted nanoscale germanium-on-insulator (GeOI) p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET) is established by solving two-dimensional Poisson's equation to derive the surface potential and inversion charge in the channel region. This drain current model includes velocity-saturation, channel-length modulation and mobility-modulation effects; and it simultaneously considers the impacts of the interface-trapped charges at both gate oxide/channel and buried oxide/channel interfaces and the fixed oxide charges on the drain current. A good agreement between the simulated drain current and experimental data is achieved in both the saturation and non-saturation regions, confirming the validity of the model. Using the model, the influences of the main structural and physical parameters on transconductance, output conductance, cut-off frequency, and voltage gain of the device are investigated. These can be served as a guide for the design of the GeOI PMOSFET.