bluuebunny/crossref_metadata_2025 huggingface dataset:
A new high precision absolute gravimeter
Authors: Hu Hua  , Wu Kang  , Shen Lei  , Li Gang  , Wang Li-Jun  ,   Joint Institute for Measurement Science, State Key Lab of Precision Measurement Technology and Instrument, Deptment of Precision Instrument and Mechanology, Tsinghua University, Beijing 100084, China
Published: December 2020

The accurate measurement of local gravitational acceleration (g, normal value 9.81 m/s2) is a key approach to the exploration of the gravitational field of the earth, and it has been applied in metrology, geodesy, geodynamics, seismology, and mineral exploration. With the plan of '2000 national gravity network' and 'China crustal motion observation network', highly precision gravity measurement will be increasingly required in the long term. In order to further investigate the possible systematic error of current absolute gravity measurement, and satisfy various requirements for highly accurate gravity observation, the T-1 absolute gravimeter prototype is designed and built at Tsinghua University. The T-1 instrument adopts the classic free-fall scheme to measure the g value by tracking the trajectory of a free-fall motion in vacuum with a laser interferometer. The T-1 absolute gravimeter consists of several sub-systems: high vacuum free-fall chamber, compact laser interferometer, low-frequency vertical vibration isolation, high-speed signal acquisition system, instrument control and data processing system. The length and time standards used in g measurement are stabilized He-Ne laser and rubidium atomic clock respectively. It's well known that both of the two standards have an uncertainty of less than 1 10-9. The practical gravity measurement results of T-1 absolute gravimeter give a standard deviation of the mean of less than 1 upGal (1 up Gal = 10-8 m/s2) in a typical observation within 12 h. And the reproducibility of less than 3 upGal is verified by repeatedly measuring gravity. The T-1 absolute gravimeter is a promising instrument by which highly accurate gravity measurement at a microgal level can be realized, and it is hopefully to be used in many research and application areas.
Approximate method of solving solitary-like wave for a class of nonlinear equation
Authors: Shi Lan-Fang  , Lin Wan-Tao  , Lin Yi-Hua  , Mo Jia-Qi  ,   College of Mathematics and Statistics, Nanjing University of Information Science and Technology, Nanjing 210044, China;,   State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamic, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;,   Department of Mathematics Anhui Normal University, Wuhu 241003, China
Published: December 2020

The approximate solitary-like wave solution for a class of disturbed evolution equation is considered using a simple and valid technique. First, an approximate solution of a corresponding typical differential equation is introduced, and then the approximate solution for an original disturbed evolution equation is obtained using the functional mapping method. It is pointed out that the series of approximate solution is convergent. The accuracy of the approximate solution is also discussed using the analytic method.
Relaxation bursting and the mechanism of four-dimensional Chua's circuit with multiple interfaces
Authors: Zhang Xiao-Fang  , Chen Xiao-Ke  , Bi Qin-Sheng  ,   Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang 212013, China
Published: December 2020

Based on the classical Chua's circuit, a four-dimensional Generalized Chua's circuit with multiple interfaces is established by introducing feedback elements. For the appropriate condition, there exists a difference in order of magnitude between the variables of state and a fast-slow coupled system, thereby forming a fast- and slow-coupled system at time scale. Analyzing the equilibrium points and the characteristics of the fast subsystems, and combining the theory of Clarke differential inclusions, the singularities on the non-smooth boundaries are explored. Two types of periodic bursting phenomena for different conditions are presented. Fast-slow analysis is employed to explore the special cluster phenomenon while the system trajectory passes across multiple interfaces. The coexisting different bursting mechanisms for the case with multiple attractors are explored in detail, while the influence of non-smooth bifurcations on bursting behavior is revealed.
Dynamical mechanism of ramp compensation for switching converter
Authors: Yang Ping  , Bao Bo-Cheng  , Sha Jin  , Xu Jian-Ping  ,   School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China;,   School of Information Science and Engineering, Changzhou University, Changzhou 213164, China
Published: December 2020

By introducing ramp compensation current into the feedback control circuit of current controlled switching DC-DC converter it can not only effectively extend the stable operation range of the switching DC-DC converter to realize chaotic stability control, but also shift its operation mode from discontinuous conduction mode to continuous conduction mode to realize operation mode shift. Taking current-controlled buck-boost converter as example by establishing the two-dimensional discrete-time model and the corresponding Jacobian matrix of current-controlled buck-boost converter with ramp compensation and two inductor current borders, the dynamical mechanism of ramp compensation for switching DC-DC converter is investigated. By analyzing the conditions of the instability and border collision bifurcation, the effects of the ramp compensation on the stable period oscillation and operation mode shift of switching DC-DC converter are discussed, and the corresponding stability boundary and mode shift boundary are obtained. Finally, an experimental circuit is built and the results are observed, from which the physical significance of the ramp compensation for chaotic stability control and operation mode shift of switching DC-DC converter is illustrated and the correctness of theoretical analysis is verified.
Effects of the aging and systole of heart on the dynamics of spiral wave
Authors: Liu Hai-Ying  , Yang Cui-Yun  , Tang Guo-Ning  ,   College of Physics and Technology, Guangxi Normal University, Guilin 541004, China;,   Department of Physics and Information Technology, Guilin Normal College, Guilin 541002, China
Published: December 2020

In this paper, the effects of the aging and systole of heart on the dynamics of spiral wave are studied by using the Greenberg-Hasting cellular automaton model. In this model the neighbor radius and the excitation threshold are increased in order to simulate the aging of heart, and the neighbor radius is changed alternately to simulate heart systole and diastole. The results show that the aging of heart can induce some influences on spiral wave, such as make spiral wave meandering, and even cause spiral wave to disappear; in addition, it can shorten the wavelength and keep period fixed, and also elongate the wavelength and increase the period of spiral wave. If the aging and the regular systole of heart take place at the same time, we observe some phenomena, such as different spiral wave patterns, the spiral wave breakup and disappearance. We also obtain the probabilities of heart failure, ventricular fibrillation and death. These results are essentially consistent with the results of relevant epidemiological survey.
Control of few node genetic regulatory networks
Authors: Ye Wei-Ming  , Lü Bin-Bin  , Zhao Chen  , Di Zeng-Ru  ,   Department of Systems Science, School of Management Beijing Normal University, Beijing 100875, China;,   National Engineering Research Center for Rare Earth Materials, General Research Institute for Nonferrous Metals, Grirem Advanced Materials Co., Ltd., Beijing 100088, China
Published: December 2020

Recently, self-organized oscillation networks have aroused great interest in diverse natural and social fields. Genetic regulatory networks are one of the most typical examples of this kind. They control the growth and develop of organism. We investigate the control of few node genetic regulatory networks. We use a method of multiple phase advanced driving to control the networks, which can improve the control efficiency. The numerical simulation, results show that for the network in which system parameter is fixed, the control efficiency will reach 95% (for 10-node network), and the method will also applicable for the network in which system parameter is unfixed.
Ab-initio calculations of the crystal-field parameters and energy level structure for Yb3+ doped in tantalate
Authors: Gao Jin-Yun  , Zhang Qing-Li  , Sun Dun-Lu  , Liu Wen-Peng  , Yang Hua-Jun  , Wang Xiao-Fei  , Yin Shao-Tang  ,   Anhui Provincial Key Laboratory of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China;,   Graduate School of the Chinese Academy of Science, Beijing 100049, China
Published: December 2020

In this paper, the DV-X method of ab-initio calculations and the effective Hamiltonian model are introduced to calculate the crystal-field and spin-orbit parameters of rare earth ions doped in various crystals, especially for the crystal with low-symmetry. For the low-symmetry crystal, the number of parameters is more than that of energy levels, thus experimental energy levels fitting cannot determine all parameters, while ab-initio calculations can determine all crystal-field and spin-orbit parameters accurately. Firstly, the crystal-field and spin-orbit parameters of Yb3+ doped in GdTaO4 crystal are calculated by this model, and then the energy level structure of Yb3+:GdTaO4 is given and the continuous emission band of Yb3+:GdTaO4 emission spectrum is analyzed, which is conducive to the laser tunable and laser mode-locking output, so Yb3+:GdTaO4 is a potential laser medium for high efficiency laser operation and new ultrashort pulse output. Also, the crystal-field and spin-orbit parameters of Yb3+ doped in YTaO4 and ScTaO4 are calculated by this model, and the energy level structures of Yb3+:YTaO4 and Yb3+ :ScTaO4 are given, which leads to a conclusion similar to that drawn from the Yb3+:GdTaO4 crystal.
SnS molecular structure and properties under external electric field
Authors: Huang Duo-Hui  , Wang Fan-Hou  , Wan Ming-Jie  , Jiang Gang  ,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;,   Yibin University Key Laboratory of Computational Physics, Yibin University, Yibin 644000, China
Published: December 2020

Structure of the SnS ground state molecule is optimized by employing density functional theory (B3P86) method with 6-311++G** basis sets for S atom and SDB-cc-pVTZ for Sn atom. The effects of electric filed ranging from -0.04 to 0.04 a.u. are investigated on bond length, total energy, the highest occupied molecular orbital (HOMO) energy level, the lowest unoccupied molecular orbital (LUMO) energy level, energy gap, mulliken atomic charges, harmonic frequency and infrared intensity of SnS ground state molecule. The excited properties of SnS molecule under different electric fields are also studied by using time dependent density functional theory (TD-B3P86) method. The results show that the bond length and infrared intensity are proved to first decrease, then increase with the external field increasing, but the total energy, HOMO energy EH and harmonic frequency are found to first increase, then decrease. The LUMO energy EL and energy gap Eg are proved to decrease with positive direction electric field increasing. The transition wavelengths from the ground state to the first nine excited states increase with positive direction electric field increasing, but excited energies from the ground state to the first nine excited states decrease.
A study on spectroscopic parameters of X2+, A2 and B2+ low-lying electronic states of SiN radical
Authors: Wang Jie-Min  , Feng Heng-Qiang  , Sun Jin-Feng  , Shi De-Heng  , Li Wen-Tao  , Zhu Zun-Lüe  ,   College of Physics and Electronic Information, Luoyang Normal College, Luoyang 471022, China;,   College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The potential energy curves (PECs) of X2+, A2 and B2+ low-lying electronic states of SiN radical are investigated using the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach combining the full valence complete active space self-consistent field method. In the present calculations, the basis sets used are correlation-consistent basis sets, aug-cc-pV6Z. The PECs determined by the MRCI calculations are corrected for size-extensivity errors by means of the Davidson modification (MRCI +Q). To obtain more reliable results, effects of the core-valence correlation and relativistic correction on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCV5Z basis set The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. With these PECs, the spectroscopic parameters are determined. A comparison with the experimental data shows that the present spectroscopic parameters are more accurate than the previous calculations.
Simulation and experiment demonstration of a polarization-independent dual-directional absorption metamaterial absorber
Authors: Lu Lei  , Qu Shao-Bo  , Xia Song  , Xu Zhuo  , Ma Hua  , Wang Jia-Fu  , Yu Fei  ,   Science College, 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
Published: December 2020

In this paper, we design and fabricat a polarization-independent dual-directional metamaterial absorber. The simulation results indicate that the absorber keeps good absorbing performance in a wide incidence angles for both transverse electric and transverse magnetic polarization, and that the high absorption is due to the dielectric loss of substrates. The experimental results indicate that the absorber achieves dual-directional high absorption at normal incidence, and that the peak absorptions are 95.9% and 90.8%, respectively. The metamaterial absorber is very thin, and its thickness is approximately 1/34 of the working wavelength. The metamaterial absorber has many advantages such as high absorption, small thickness, simple design and easy processing.
Study of quartz temperature characteristics for precise oscillator applications
Authors: Zhu Hua-Bing  , Wu Zheng-Bin  , Liu Guo-Qiang  , Xi Kui  , Li Shan-Shan  , Dong Yang-Yang  ,   Institute of New Weaponry and Application, Naval University of Engineering, Wuhan 430033, China;,   Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 China;,   Guangdong Failong Crystal Technology Co., Ltd, Dongguan 523757, China
Published: December 2020

In this paper, we report on the study of quartz material characteristic variation with temperature for precision oscillator applications with a novel piezoelectric material precise characterization method. Electrical impedance resonant characteristics of AT cut quartz sample are measured at temperatures ranging from ambient temperature up to 100 ℃. These measured results are fitted with a simulated annealing optimization algorithm to accurately calculate complex material parameters comprising loss characteristics. Effects of temperature change on quartz material characteristics and their loss are analyzed. This paper offers theoretical and technical supports to the design of precision oscillators with stable temperature characteristics.
Fractal analysis of spontaneous imbibition mechanism in fractured-porous dual media reservoir
Authors: Cai Jian-Chao  , Guo Shi-Li  , You Li-Jun  , Hu Xiang-Yun  ,   State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China;,   Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, China
Published: December 2020

Low permeability oil reservoirs are usually accompanied with fracture development, forming fracture-matrix dual porosity medium. Spontaneous imbibition is a crucially important recovery mechanism in naturally fractured reservoir with water deriving, in which non-wetting phase is displaced in either co-current or counter-current manner. In this work, the criterion (inverse bond number) and fractal model for spontaneous imbibition mechanism of dual-porosity medium are developed, and the analytical expression for structure constant is also derived based on the fractal characteristics of pores in porous matrix. The improved fractal model for inverse bond number can be expressed as a function of porosity, pore fractal dimension, flow tortuosity, maximum pore diameter, height of matrix, density difference between oil and water, interfacial tension and contact angle. The present model predictions are shown to be in agreement with the available results. The dominion for criterion of imbibition mechanism is plotted, which provides a theoretical basis of adding surfactant in water for enhancing oil recovery in low permeability reservoirs.
Theoretical study on the electron energy distribution function of weakly ionized air plasma
Authors: Zhou Qian-Hong  , Dong Zhi-Wei  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

The electron energy distribution function (EEDF) of weakly ionized air plasma (79% nitrogen and 21% oxygen) is investigated by solving the Boltzmann equation with the spherical harmonics expansion. It is found that the EEDF deceases sharply in an energy range from 2 to 3 eV for low reduced field (E/N 100 Td), and the high energy tail of the EEDF decreases more sharply than Maxwell distribution. When the reduced field increases to a range 400 to 2000 Td, the EEDF approaches to Maxwell distribution. When the reduced field is greater than 2000 Td, the high energy tail (200 eV) of the EEDF deceases more slowly than Maxwell distribution. It is shown that the EEDF approaches to Maxwell distribution in a high frequency field. The effective electron temperature is dependent only on E/ for vm, but on E/N for vm. The electron-electron collisions play no significant role until the ionization degree is bigger than 0.1%. This is different from the case of monatomic plasmas, in which the EEDF is influenced by electron-electron collisions for ionization degree greater than 10-6.
Radiation model and experimental research on novel pinhole-assisted point-projection backlight
Authors: Yan Ji  , Wei Min-Xi  , Pu Yu-Dong  , Liu Shen-Ye  , Zhan Xia-Yu  , Lin Zhi-Wei  , Zheng Jian-Hua  , Jiang Shao-En  ,   Research Center of Laser Fusion, China Academy of Engineering Physiacs, Mianyang 621900, China
Published: December 2020

High flux, Multi-keV X-rays, can be efficiently produced from nano-second laser interaction with metal target. Multi-keV backlight X-ray source is very important in inertial confinement fusion and high-energy density physics research. The one-dimensional numerical simulation results propose a laser plasmas radiation model, and the model is compared well with Shenguang II experimental results. The pinhole-assisted point-projection (PAPP) backlight is improved by the model; the rear-on PAPP backlight for low-Z metal target and the side-on PAPP backlight for middle-Z metal target are developed. The experiment is performed on Shenguang II 9th laser facility. The static stream line obtained with novel PAPP backlight provides high-quality capsule image, and the spatial resolution is better than 10 μm. Results show that novel PAPP backlight has advantages of traditional PAPP in source brightness, spatial resolution and image contrast.
Structure transformation and magnetisms in Ho2Ni7-xFex compounds
Authors: Yang Yu-Qi  , Gao Qing-Qing  , Li Guan-Nan  ,   Jiangxi University of Science and Technology, Ganzhou 341000, China;,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

Based on the composite compounds Ho2Ni7-xFex (x=0-3.0), a method of describing the structure transition from rhombohedral to hexagonal is discussed in terms of free electron concentration. The transition is investigated by X-ray powder diffraction and magnetic analysis. The compounds crystallize into the rhombohedral Gd2Co7-type structure for x=0-0.5 and into the hexagonal Ce2Ni7-type structure for x=0.5-2.5. The values of lattice parameters a and c of the Ho2Ni7-xFex compounds increase with the addition of Fe, and the saturation magnetization Ms decreases with Fe content increasing at a rate of d Ms/d x=-2, manifesting antiparallel alignments of the Fe and Ho moment. The higher the free electron concentration, the stabler the rhombohedral structure is, otherwise the hexagonal structure is stabler, which provides a meaningful parameter to distinguish the two allotropies in composite structure intermetallics.
Prediction of the magneto-resistivity of manganese oxides La0.67Ca0.33MnO3 and Pr0.7Sr0.3MnO3 via temperature and magnetic field
Authors: Liu Ya-Jie  ,   Division of Mathematics, Physics and Information Engineering, Nanhu Department, Jiaxing College, Jiaxing 314001, China
Published: December 2020

The resistivity related to temperature and magnetic field is a crucial parameter for determining the physical properties of the perovskite-type manganese oxide. The first task of this work is to find out a suitable method to predict the resistivities of La0.67Ca0.33MnO3 and Pr0.7Sr0.3MnO3 in the process from insulator phase to the metal phase via the temperature and the magnetic field. Based on the nonlinear numerical fitting, an analytical expression showing the dependence of the resistivity on temperature both less than and higher than the metal-insulator transition Curie temperature (TC) at different magnetic fields, and the maximum resistivity (ρmax) corresponding to each Curie temperature is acquired. The second task of this work is to trace a mathematical relationship between the magnetic field and the maximum resistivity, and the Boltzmann function can be used successfully by numerical fitting. The lowest correlation coefficient and the largest average relative error between the actual and the calculated data are 0.998 and 4.35% in all considered cases respectively.
Lipid exhange between membranes: effects of temperature and ionic strength
Authors: Jiang Zhong-Ying  , Zhang Guo-Liang  , Ma Jing  , Zhu Tao  ,   School of Electronics and Information, Yili Normal University, Yining 835000, China;,   College of Physics, Nanjing University, Nanjing 210093, China
Published: December 2020

Transmembrane lipid exchange is critical to membrane function and pharmaceutical application. The exchange process is not fully understood and it is explored by quartz crystal microbalance with dissipation monitor method in this paper. It is found that the vesicle deformation discrepancy is not significant for the supported-lipid-bilayer-attached vesicles under different thermal and ionic strength conditions. And hence the total intermembrane contact area is determined by the vesicle adsorption amount. The maximum total intermembrane contact area decreases with the increase of temperature and the decrease of ionic strength. The changes of the vesicle adsorption rate and the transmembrane lipid exchange rate induced by temperature and ionic strength are elucidated to understand the observation above. The study helps explain some physiological phenomena and provides some guidelines for drug delivery researches.
Responses of the land-surface process and its parameters over the natural vegetation underlying surface of the middle of Gansu in loess plateau to precipitation fluctuation
Authors: Zhang Qiang  , Li Hong-Yu  , Zhang Li-Yang  , Yue Ping  , Shi Jin-Sen  ,   Institute of Arid Meteorology, CMA, Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province; Key Open Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Lanzhou 730020, China;,   Gansu Provincial Meteorological Bureau, Lanzhou 730020, China;,   College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
Published: December 2020

The Loess Plateau is well known as a specific region sensitive to global climate change, and thus its land-surface process is significantly influenced by climatic fluctuation. Up to now, the land-surface physical process over the Loess Plateau has been basically understood under a specific climatic condition, but the dynamic variation regularity of land-surface process in different climatic states is still lacking in its knowledge. Utilizing the continuous five-year data collected at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) supported by the program 'the Loess Plateau Land-surface Process Experiment (LOPEX)', in this paper, we systematically analyze the regularity of responses of factors including land-surface water and energy budget as well as surface albedo and roughness to climatic fluctuation over the natural vegetation surface of Loess Plateau. The results show that the land-surface process and its relevant parameters are very sensitive to the fluctuations of annual precipitation. Besides, they respond markedly to annual rainfall amount and are also closely related to the nature of rainfall. Soil moisture fluctuales not fully with total amount of rainfall but rises with the increase of effective precipitation with which land-surface water and energy budget also vary. In addition, the vertical sensible heat advection goes up with rainfall increasing, while the trend of surface energy imbalance is opposite. The averaged albedo in summer half-year comes down with the increase of the ratio of effective precipitation to the climatic average, but yearly averaged albedo is evidently affected by the snow-accumulating winter time and rises with the increase of snow-accumulating hours. Soil thermal conductivity and surface roughness both increase with annual effective precipitation increasing to the climatic average, but they are more sensitive to the precipitation fluctuation under a low precipitation condition than under the normal precipitation condition. However, land-surface process parameters over the natural vegetable surface of Loess Plateau basically fluctuate between those of deserts and farmland, and have not yet broken the climatic restrictions. Fitting relationship is used to quantitatively reflect the regularity of response of the parameters to rainfall fluctuations so as to evidently eliminate possible bias brought to numerical models and microclimatic analysis by the previous fixed and un-dynamic changeable land-surface parameters.
Key nodes in complex networks identified by multi-attribute decision-making method
Authors: Yu Hui  , Liu Zun  , Li Yong-Jun  ,   School of Computer Science, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

In complex networks, it is significant how to rank the nodes according to their importance. Most of the existing methods of ranking key nodes (e.g. degree-based, betweenness-based) only consider one factor but not the integration of whole complex network in evaluating the importance of nodes, so those methods each have a limited application range. In this paper, a multi-attribute decision-making method to identify the key nodes in complex networks is proposed. In our method, each node is regarded as a solution, and each importance evaluation criterion as one solution's attribute. After that, we calculate the closeness between each solution and the ideal solution in order to obtain the integration results of node importance in complex networks. The proposed method can be used in a variety of complex networks. It is also easy to evaluate the importance evaluation criteria. Finally, experimental results show that the proposed method is effective.
An ameliorative algorithm of two-dimensional Poisson equation based on genetic parallel successive over-relaxation method
Authors: Peng Wu  , He Yi-Gang  , Fang Ge-Feng  , Fan Xiao-Teng  ,   College of Electrical and Information Engineering, Hunan University, Changsha 410082, China;,   School of Electrical and Automation Engineering, Hefei University of Technology, Hefei 230009, China;,   The 41st Research Institute of China Electronics Technology Group Corporation, Qingdao 266555, China
Published: December 2020

There exist some disadvantages in the calculation of two-dimensional Poisson equation with several common methods. A new ameliorative algorithm is presented. It is based on a parallel successive over-relaxation (PSOR) method, by using the multi-objective genetic algorithm to search for optimal relaxation factor, with which the problem of optimal relaxation factor selection in PSOR is solved. The multi-objective fitness function is constructed, with which the genetic algorithm parameters are optimized. The analysis mainly focuses on algorithm computation, time cost and accuracy of error correction. The performance of the ameliorative algorithm is compared with those of Jacobi, Gauss-Seidel, Successive over relaxation iteration (SOR) and PSOR. Experimental results show that relaxation factor has a significant effect on the speed of solving Poisson equation, as well as the accuracy. The improved algorithm can increase the speed of iteration and obtain higher accuracy than traditional algorithm. It is suited for solving complicated finite difference time domain equations which need high accuracy. The higher the accuracy requirement, the better the performance of the algorithm is and the more computation time can also be saved.
Oscillations and non-smooth bifurcation analysis of Chen system with periodic switches
Authors: Yu Yue  , Zhang Chun  , Han Xiu-Jing  , Jiang Hai-Bo  , Bi Qin-Sheng  ,   Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang 212013, China;,   Facuity of Science, Nantong University, Nantong 226019, China
Published: December 2020

Complicated behaviors of a compound system with periodic switches between different types of Chen systems are investigated in detail. In the local analysis, the critical conditions such as fold bifurcation and Hopf bifurcation are derived to explore the bifurcations of the compound systems with different stable solutions in the two subsystems. Different types of oscillations of this switched system are observed, of which the mechanism is presented to show that the trajectories of the oscillations can be divided into several parts by the switching points, governed by the two subsystems respectively. Because of the non-smooth characteristics at the switching points, different forms of bifurcations may occur in the compound system, which may result in complicated dynamics such as chaotic oscillations, instead of the simple connections between the trajectories of the two subsystems. By the Poincaré mapping, the location of the fixed point and Floquet characteristic multiplier of switching system are discussed.With the variation of the parameter, the system can evolve into chaos via the cascading of period-doubling bifurcation. Besides, the system can evolve into chaos immediately by saddle-node bifurcations from period solutions.The non-smooth bifurcation mechanism of periodic switching system can be revealed by the research.
Dynamics analysis and synchronization of T chaotic system with its circuit simulation
Authors: Wang Zhen  , Sun Wei  ,   Department of Foundation, Xijing University, Xi'an 710123, China;,   School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

The stability of equilibrium of a T chaotic system is analyzed, and the system bifurcation, Lyapunov exponent, Poincare section with numerical analysis are studied. Also, the synchronization problem with T chaotic systems with known or unknown parameters is studied in this paper. According to the Lyapunov function, feedback controller of the system is designed and has been proved. An electronic circuit is designed to realize the controller using Multisim. The simulation results demonstrate the effectiveness and realizableness of the proposed method.
Measurements and analyses of uranium reaction rates on a depleted uranium shell with D-T neutrons
Authors: Yang Yi-Wei  , Yan Xiao-Song  , Liu Rong  , Lu Xin-Xin  , Jiang Li  , Wang Mei  , Lin Ju-Fang  ,   Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China;,   Department of Engineering Physics, Tsinghua University, Beijing 100084, China
Published: December 2020

Aiming at checking the conceptual design of the subcritical reactor, an experiment using activation technique was carried out on a depleted uranium shell of R19.4/30.0 cm with D-T neutrons. The 6 depleted uranium foils were activated at 90° with respect to the incident D beam in the shell, and distributions of 238U (n, γ) reaction rates, 238U (n, f) reaction rates, 238U (n, f) reaction rates and 238U (n, 2n) reaction rates were obtained, by measuring characteristic γ rays generated by corresponding uranium reactions. The relative uncertainties are 3.6%–3.7% for 238U (n, γ) reaction rates, 5.1%–5.9% for 238U (n, f) reaction rates and 238U (n, f) reaction rates, and 4.3%–4.7% for 238U (n, 2n) reaction rates. The experiment was simulated using MCNP5 code with ENDF66c library, and the calculation-to-experiment ratios are 0.972–1.034 for 238U (n, γ) reaction rates, 0.983–1.058 for 238U (n, f) reaction rates and 238U (n, f) reaction rates, and 0.979–1.019 for 238U (n, 2n) reaction rates.
All-optical diode in mid-infrared waveband based on self-phase modulation effect in silicon ring resonator
Authors: Zhang Xue-Zhi  , Feng Ming  , Zhang Xin-Zheng  ,   The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin 300071, China
Published: December 2020

Nonreciprocal transmission device is one of the fundamental elements in integrated optics, and mid-infrared is a widely used waveband in many areas, such as remote sensing or spectrum analysis. An all-optical diode based on self-phase modulation (SPM) effect is numerically demonstrated in mid-infrared waveband. The diode consists of a linear waveguide and double silicon ring resonators. The nonreciprocal transmission ratio can be more than 20 dB in a power range between 0.5 mW and 20 mW, while the transmission loss in forward direction is less than 10 dB. Moreover, the influences of linear absorption coefficient of ring resonators and the bi-stability effect on the performance of the diode are discussed.
High-quality digital image-plane micro-holographic system with the same wavefront curvature of reference and object wave
Authors: Wang Hua-Ying  , Liu Fei-Fei  , Song Xiu-Fa  , Liao Wei  , Zhao Bao-Qun  , Yu Meng-Jie  , Liu Zuo-Qiang  ,   Scholl of Information & Electrical Engineering, Hebei University of Engineering, Handan 056038, China;,   College of Science, Hebei University of Engineering, Handan 056038, China
Published: December 2020

The digital image-plane holographic microscopy which has the same curvature radius in the object light path and the reference light path is studied for the first time to our knowledge. The configuration of this setup is analyzed and built. The point spread function of this system is derived. The factors corresponding to the imaging resolution and the imaging characteristics of this system are analyzed. The method to correct the linear phase distortion in the reconstructed optical field is discussed. The results show that this system has the largest information content, and the imaging resolution of the system is dependent on the numerical aperture of the microscope objective (MO) and on the CCD pixel size, but independent of the photosensitive surface size of the CCD. All frequency components of each point in the object wave which has passed through the MO can completely be recorded and reconstructed. And the size of illuminated region of object has no influence on the recording condition and the quality of the reconstructed image. The digital image-plane holographic microscopy with the same curvature radius in the object light path and the reference light path is an optimized holographic recording system, which can achieve high-quality imaging. The experimental results demonstrate the correctness of the theoretical analysis.
Isochronal chaos synchronization of a chain mutually coupled semiconductor lasers
Authors: Liu Ying-Ying  , Pan Wei  , Jiang Ning  , Xiang Shui-Ying  , Lin Yu-Dong  ,   School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

In this paper, a chaotic synchronization system model of a chain mutually coupled semiconductor lasers is established by adding a relay laser between the mutually coupled semiconductor lasers with cavity. The isochronal chaos synchronization condition is theoretically analysed. The influences of injection current, mutual coupling strength and feedback strength on isochronal chaos synchronization are numerically studied. The distributions of synchronous quality in the two-dimensional parameter space for mutual coupling strength and feedback strength are revealed. We show that when the injection current is big enough and the mutual coupling conditions and feedback conditions are completely the same, the stable isochronal chaos synchronization with high quality can be obtained among all the lasers. Stable isochronal chaos synchronization between central laser and side laser is distributed in the area when both mutual coupling strength and feedback strength are small or similar. Two side lasers can easily achieve the stable isochronal chaos synchronization with high quality, because they receive the same injection from central laser at the same time. The system model can be further expanded into the realizing of remote two-way isochronal chaos synchronization or the isochronal chaos synchronization of the arrayed semiconductor laser system.
Research on magnetic control mechanism of four-wave mixing in highly nonlinear fiber
Authors: Li Shu-Biao  , Wu Bao-Jian  , Wen Feng  , Han Rui  ,   Key Laboratory of Optical Fiber Sensing and Communications of the Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
Published: December 2020

According to the coupled-mode theory for guided optical waves, the mechanism of magneto-optical four-wave mixing (MO-FWM) existing in a fiber with magneto-optic effect and nonlinear effect both serving as perturbation is analyzed. The influence of applied magnetic field on the polarization dependency of FWM is measured, and the experimental results are in agreement with the theoretical analyses. It is shown that the magnetic control function of FWM can be identified easily for the incident orthogonal states of polarization. The FWM efficiency is dependent on the MO coupling coefficient in the oscillation form and can be further improved under an appropriate bias magnetic field. The MO-FWM effect can also be applied to magnetic field sensing, and the operating range is determined by the Verdet constant of highly nonlinear fiber.
Design and analysis of guided-mode resonance filter containing an absentee layer with an antireflective surface
Authors: Sang Tian  , Cai Tuo  , Liu Fang  , Cai Shao-Hong  , Zhang Da-Wei  ,   School of Optical-Electrical and Computer Engineering, Shanghai Key Lab of Modern Optical Systems, University of Shanghai for Science and Technology, Shanghai 200093, China;,   Department of Physics and Electronic Science, Qiannan Normal College for Nationalities, Duyun 558000;,   Guizhou Key Laboratory of Economic System Simulation, Guizhou University of Finance and Economics, Guiyang 550004
Published: December 2020

A design approach to guided-mode resonance filter containing an absentee layer with an antireflective surface is presented. This design approach is reliable for the design and analysis of guided-mode resonance filter containing an absentee layer with an antireflective surface at an arbitrary incidence. The antireflection condition of guided-mode resonance filter containing an absentee layer is obtained. For the absentee layer with a fixed optical thickness, the resonance wavelength can be selected, with the low-sideband features and the filter linewidth kept almost the same by using different materials. In addition, the resonance wavelength and its linewidth can be tuned almost linearly in a broad spectral band as the incident angle is varied due to high angular tolerance of the antireflection features of the filter in the range of small angle.
Transmission control of nonautonomous optical rogue waves in nonlinear optical media
Authors: Hu Wen-Cheng  , Zhang Jie-Fang  , Zhao Bi  , Lou Ji-Hui  ,   Institute of Nonlinear Physics, Zhejiang Normal University, Zhejiang, Jinhua 321004, China;,   Zhejiang University of Media and Communications, Hangzhou 310000, China
Published: December 2020

We propose a unified theory, that is, similarity transformation, to construct exact optical rogue wave solution of (1+1)-dimensional nonlinear Schrödinger equation with variable coefficients. Moreover, we investigate propagation dynamics of the first-order optical rogue wave in an optical fiber amplifier. In the suitable regulation of parameters, we find that the properties of the optical rogue wave, such as width, amplitude and position, are controllable in a nonlinear medium. These results give edification in theory and practical application.
Probability density function of temperature in a circular-cylinder turbulent wake
Authors: Ge Yang-Zhen  , Mi Jian-Chun  ,   State Key Laboratory of Turbulence & Complex Systems, Peking University, Beijing 100871, China
Published: December 2020

In this article, we report on an experimental research on the probability density function (PDF) of temperature measured in the wake of a circular cylinder slightly heated and its relationships with the turbulent mixedness under different Reynolds numbers (1200-8600). The temperature is measured by a probe of cold-wire with 0.63-m in diameter. Results show that the temperature PDF varies significantly with location in the wake. An increase in Reynolds number speeds up this variation, particularly accelerates the evolution from totally non-Gaussianity to near-Gaussianity along the wake centreline.
Thermal rectification and phonon scattering in silicon nanofilm with triangle hole
Authors: Ju Sheng-Hong  , Liang Xin-Gang  ,   Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, School of Aerospace, Tsinghua University, Beijing 100084, China
Published: December 2020

Thermal rectification has potential applications in the thermal management of electronics and energy saving. Discovering thermal rectification phenomena and understanding the mechanism are very essential. Reported in this paper is the thermal rectification in silicon nanofilm with triangle holes by the non-equilibrium molecular dynamics simulation. The results show that in the silicon nanofilm with triangle holes, the difference in thermal rectification coefficient is around 28% with the variation of heat flow direction in a temperature range from 300 K to 1100 K. The phonon wave packet dynamic simulations indicate that transverse phonons are generated during the scattering of longitudinal phonons in the nanofilms. When the phonon transport direction is reversed, the average phonon energy transmission coefficient is changed by about 22% in all the frequency range. The difference in phonon transmissity, which is caused by asymmetric structure, is regarded as being attributed mainly to the thermal rectification in silicon film with triangle holes.
Thermal conductivity of metallic nanoparticle
Authors: Huang Cong-Liang  , Feng Yan-Hui  , Zhang Xin-Xin  , Li Jing  , Wang Ge  , Chou Ai-Hui  ,   Department of Thermal Engineering, University of Science and Technology Beijing, Beijing 100083, China;,   School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
Published: December 2020

Concerning metallic nanoparticles, a statistical simulation method to predict the electron mean free path of a nanoparticleis developed. And the phonon-contributed specific heat and phonon group velocity are also analyzed. Then, the kinetic theory is used to obtain the electron thermal conductivity and the lattice thermal conductivity of the nanoparticles. The size dependence of these properties is further discussed. It turns out that the electron mean free path of a square nanoparticle approximates to that of a circle nanoparticle if nanoparticles are of the same characteristic length. The electron thermal conductivity is much higher than the lattice thermal conductivity on the nanoscale. Either electron or lattice thermal conductivity of nanoparticles declines with diameter decreasing, while the size dependence of electron thermal conductivity is more obvious. However, if the diameter decreases to quite a small size, the electron thermal conductivity will become as low as the lattice thermal conductivity. In addition, the electron/lattice thermal conductivity of a nanoparticle will become less size-dependent if its characteristic length is 4 times larger than corresponding bulk electron/phonon mean free path.
Temperature window of the (Al0.1Ga0.9)0.5In0.5P growth by MOCVD
Authors: Sun Pei  , Li Jian-Jun  , Deng Jun  , Han Jun  , Ma Ling-Yun  , Liu Tao  ,   Key Laboratory of Opto-electronics Technology of Education Ministry, College of Electronic Information & Control Engineering, Beijing University of Technology, Beijing 100022, China
Published: December 2020

The (Al0.1Ga0.9)0.5In0.5P, four-element alloy, whose band is direct, is used to make optoelectronic devices. The wavelength of the material is about 630nm. When it is epitaxially grown by low press-metalorganic chemical vapor deposition(LP-MOCVD), its quality will depend on temperature, one of the most important conditions. So it is essential to find out the best temperature of growth. The quantum wells of the (Al0.1Ga0.9)0.5In0.5P are grown at 700 ℃, 680 ℃, 670 ℃ and 660 ℃ respectively. The best temperature, which is found out by the results of photoluminescence PL, is about 670 ℃. The reasons are given by the results of PL, surfaces of wafers and the flow field simulation of MOCVD. The revaporization of In at high temperature and the incorporation of O at low temperature can lead to bad quality. An available path to solve growth at high temperature is to increase the effective density of In.
Progress in the blend stacked structure of organic solar cells
Authors: Yu Huang-Zhong  ,   State Key Laboratory of Subtropical Building Science, Department of Physics, South China University of Technology, Guangzhou 510640, China; Key Laboratory of Renewable Energy and Gas Hydrate, Chinese Academy of Sciences, Guangzhou 510640, China
Published: December 2020

Organic solar cells have received extensive attention due to their light weight, low cost, flexible. Because a single organic material absorbs only part of the sun light, laminated structure of solar cell, consisting of different absorption band gaps of organic material through the middle connecting layer, can both cover a larger part of the solar flux, and improve the circuit voltage or short circuit current of the solar cells. In this paper, the recent progress of the blend laminated structure polymer solar cells is summarized. Structures, principles and performances of a variety of laminated organic solar cells are introduced. The present status of research and existing problems of the blend laminated structure polymer solar cells are described, which provides valuable referesce for the study of high-performance organic solar cells.