bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel method of generating qausi-non-diffracting Mahtieu beam based on axicon
Authors: Li Dong  , Wu Feng-Tie  , Xie Xiao-Xia  ,   College of Information Science and Engineering, Huaqiao University, Fujian Key Laboratory of Optical Beam Transmission and Transformation, Xiamen 361021, China
Published: December 2020

A novel method of generating zero order non-diffracting Mathieu beam with an axicon is proposed. To create quasi non-diffracting Mahtieu beam, an axicon is used to focus a plane wave modulated by elliptical Gaussian amplitude. Based on the formula of diffraction integral of a plane wave modulated by elliptical Gaussian amplitude propagating through the axicon, the intensity of quasi non-diffracting beam is simulated numerically. The maximum propagation distance of the quasi-non-diffracting Mathieu beam is calculated according to a geometrical optical model. To verify the results of the theory, an experimental setup is designed.Using a cylindrical lens and a collimating and expanding system, a circular Gaussian beam can be converted in to a plane wave modulated by elliptical Gaussian amplitude. Focusing the plane wave using an axicon, a qausi-non-diffracting Mathieu beam can be generated. The exoerimental results are consistent with theoretical calcuations and numerical simulations.
Shielding design of the multi-purpose reflectometer of China spallation neutron source
Authors: Shen Fei  , Liang Tai-Ran  , Yin Wen  , Yu Quan-Zhi  , Zuo Tai-Sen  , Yao Ze-En  , Zhu Tao  , Liang Tian-Jiao  ,   The School of Nuclear and technology, Lanzhou University, Lanzhou 73000 China;,   Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;,   Department of Physics, Nankai University, Tianjin 300071, China
Published: December 2020

The shielding design employing the Monte Carlo simulation code of MCNPX 2.5.0 for multi-purpose reflectometer of China spallation neutron source (CSNS) is introduced, including the shielding needs, radiation source terms, calculating methods and simulation results, etc. Various radiation source terms such as the moderator leakage source term, and the neutron guide loss source term etc. are taken into account in the simulation, and step-by-step calculation method and variance reduction methods such as source angular biasing, source energy biasing, and geometry splitting, are adopted to improve the computing speed while the precision of the results is guaranteed. In the shielding design of instrument transport beamline, second shutter, and scattering room etc., the final shielding parameters are determined by comparing the shielding need under different operating conditions, to ensure the dose rate below the 2.5 Sv/h limitation in accessible locations outside the shielding.
A method of vertical and horizontal plus cubic spline interpolation for Mie scattering lidar profile data
Authors: Chen Hao  , Hua Deng-Xin  , Zhang Yi-Kun  , Zhu Cheng-Xuan  ,   School of Mechanical & Instrumental Engineering, Xi'an University of Technology, Xi'an 710048, China;,   School of Computer Science & Engineering, Xi'an University of Technology, Xi'an 710048, China
Published: December 2020

Since the traditional spatial data interpolation method has its limits in describing the RHI (range-height indicator) graph for Mie scattering lidar scanning profile, it cannot be applied to the visualization of Mie scattering lidar space-time scan data, and it is also difficult to achieve the continuity in atmospheric parameters evolution process. This paper analyzes the space-position relations in lidar scanning profile data based on the scanning elevation and spatial distribution characteristics of the atmospheric parameters, chooses the reference data rationally of vertical and horizontal positions, and gives the position relevant weight. The smoothness of data is revised by a cubic spline function and the missing data are replenished by interpolation finally. Results show that this method can improve effectively the accuracy of atmospheric lidar scanning data space interpolation, produce few errors; and the RHI graph becomes smooth, thus it conforms to the overall change rule of atmospheric parameters.
Doubled temperature measurement range for a single micro-ring sensor
Authors: Li Xin  , Wang Lu-Na  , Guo Shi-Liang  , Li Zhi-Quan  , Yang Ming  ,   Control and Simulation Center, Harbin Institute of Technology, Harbin 150080, China;,   Institute of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China
Published: December 2020

A novel SOI (silicon on insulator) temperature sensor based on a U-shaped waveguide-coupled single micro-ring is proposed in this paper. Refractive index and length of the temperature-sensing part will change as the temperature changes, leading to the shift of the output spectrum of the sensor. The transfer function of the U-shaped waveguide coupled with a single micro-ring is obtained based on the theory of coupling modes and transfer matrix method. And we have studied the output spectrum properties of the system from different temperature-sensing parts. Results show that the whole structure of U-shaped waveguide coupled with the single micro-ring proves to be the best temperature-sensing part as the output spectrum with no spurious modes and a deep extinction ratio of 31 dB. Compared with the traditional two waveguides coupled with a single micro-ring resonator, when the distance between the two coupling points of the U-shaped waveguide is an integer multiple of circumference of the micro-ring, the free spectrum range (FSR) can be expanded to 56 nm, the sensitivity can achieve 89.2 pm/℃, and the measurement range be 298720 K, achieving a high temperature measurement of SOI micro-ring resonator.
Experimental demonstration on triangular-shaped pulse train generation based on harmonic fitting
Authors: Li Jing  , Ning Ti-Gang  , Pei Li  , Jian Wei  , Zheng Jing-Jing  , You Hai-Dong  , Sun Jian  , Wang Yi-Qun  , Li Chao  ,   Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044, China;,   Science and Information College, Qingdao Agricultural University, Qingdao 266109, China
Published: December 2020

We demonstrate an approach for triangular-shaped pulse train generation experimentally based on harmonic fitting. The operation principle is that a Mach-Zehnder modulator is firstly employed to suppress modulation of the optical carrier. Thus a periodically variable lightwave can be obtained at the output. Then the signal is coupled into a section of dispersive fiber. Due to the dispersion-induced power fading, the undesired 4th order harmonics in the optical intensity can be fully removed. By adjusting modulation index to an optimum value (m=2.305), the generated harmonics of the optical intensity can be made corresponding to the Fourier components of typical periodic triangular pulses. Finally, the triangular-shaped pulse train at a repetition rate two times of the driving frequency can be obtained. In the experiments, 19.724 Gb/s and 15.356 Gb/s triangular-shaped pulse trains are generated by using 9.862 GHz and 7.678 GHz driving signals respectively. Besides, the repetition rate can be switched to another value by using a different fiber dispersion ( 2L). It is found that the experimental data agree well with theoretical results.
Synthesis and upconversion luminescent properties of BaMgF4：Er3+, Yb3+ nanocrystals
Authors: Pan Cheng-Long  , Liu Hong-Li  , Guo Yun  , Jing Shu  , Sun Jing  , Zhou He-Feng  , Wang Hua  ,   Key Laboratory of Interface Science and Engineering, Taiyuan University of Technology, Ministry of Education, New Materials, Taiyuan 030024, China
Published: December 2020

BaMgF4:Er3+, Yb3+ nanocrystals in rod-shape are synthesized by means of the reverse co-precipitation. They emit green and red light under excitation of near-infrared light (980 nm). The green and red emissions may be attributed to the 2H11/24I15/2, 4S3/24I15/2 and 4F9/24I15/2 transitions of Er3+. Dopant ions Yb3+ as sensibilizers can improve the upconversion transformation efficiency. The emission intensity is the strongest when the contents of Er3+ and Yb3+ are 3% and 10%, respectively. With increasing concentration of Yb3+, the red emission intensity increases while the green emission reduces. And the conversion fitting curve between the luminous intensity and pump current indicates that the upconversion process of the green and red light of BaMgF4: Er3+, Yb3+ is due to two-photon absorption.
Research of the characteristics of photonic crystals based on air holes sub-wavelength imaging
Authors: Zhan Sheng-Gao  , Liang Bin-Ming  , Zhu Xing-Fu  , Chen Jia-Bi  , Zhuang Song-Lin  ,   College of Optical & Electronic Information Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
Published: December 2020

Negative refractivity has been extensively studied, especially in the perfect imaging photonic crystal slab, for its fantastic characteristics. The photonic crystals sub-wavelength imaging is investigated by finite-difference time-domain (FDTD) simulation and numerical analysis. Impact of wavelength and temperature drift on the sub-wavelength imaging of photonic crystal with negative refraction has been studied in this paper.
Bezier interpolation method for the dynamics of rotating flexible cantilever beam
Authors: Fan Ji-Hua  , Zhang Ding-Guo  ,   School of Sciences, Nanjing University of Science and Technology, Nanjing 210094, China;,   School of Mechanical-Electronic and Automotive Engineering, Jiangsu University of Science and Technology, Zhangjiagang 215600, China
Published: December 2020

The Bezier interpolation is introduced as a new discretization method for the rotating flexible beam deformation. First, the model of the rotating flexible beam is built. Then, the rigid-flexible coupling dynamic equations are established via employing the second kind of Lagrange's equation. The longitudinal deformation and the transverse deformation of the flexible beam are considered, and the coupling term of the deformation which is caused by the transverse deformation is included in the total longitudinal deformation; and a software package for the dynamics simulation of the flexible beam is developed. Finally, the simulation results of the Bezier interpolation are compared with those of the assumed method and the finite element method. Simulation results demonstrate that the computational efficiency of the Bezier interpolation is the highest, the computational accuracy of Bezier interpolation is in accordance with the needs of engineering, and is higher than the one of assumed mode method in high-speed case. The Bezier interpolation method is better than the assumed mode method in dealing with the large deformation dynamics problem. So the Bezier interpolation method will be hopeful to win popularity in the field of multi-body system dynamics.
Simulation study of interface instability in metals driven by cylindrical implosion
Authors: Liu Jun  , Feng Qi-Jing  , Zhou Hai-Bing  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
Published: December 2020

Simulation of metal instability with the initial sine perturbation on the inside of the metal shell driven by cylindrical implosion is made, and the simulation results is in accordance with the experiments. By comparing with the simulation result without considering the strength of the metals, the analysis shows that the strength of unmelted metal has a strong inhibitory effect to the metal instability, and under certain loading conditions the growth rate of the perturbation will decrease with the increase of the perturbation mode number. After that, the laws of the metal instability under explosive-driven conditions are summarized. Before the implosion reflected wave arrives at the shell, RM instability plays a dominant role. After the implosion reflected wave is applied to the shell, RT instability is significantly enhanced, the effect combined with the strength of the perturbations shows a nonlinear evolution. Under both RM and RT instability condition, the strength of metal could cause the cutoff wavelength to exist in unmelted state.
Deformation modeling of InSb IRFPAs under liquid nitrogen shock
Authors: Zhang Xiao-Ling  , Meng Qing-Duan  , Zhang Li-Wen  , Geng Dong-Feng  , Lü Yan-Qiu  ,   School of Information Engineering, Henan University of Science and Technology, Luoyang 471023, China;,   School of Electrical Engineering, Henan University of Science and Technology, Luoyang 471023, China;,   China Airborne Missile Academy, Luoyang 471009, China
Published: December 2020

The deformation appearing in InSb infrared focal plane arrays (IRFPAs) as subjected to liquid nitrogen shock tests, is an important criterion to assess the reliability of the structure designed and to predict the number of thermal cycling after which no cracks appear in InSb IRFPAs. After analyzing both the deformation distribution and the deformation running directions appearing in InSb IRFPAs at 77 K, we assume that the thermal strain accumulated in the liquid nitrogen shock test is completely relaxed. Based on this assumption and according to the temperature rising curve, we may obtain the deformation distribution in InSb IRFPAs at room temperature, which is identical in the deformation charactristics to the photograph of InSb IRFPAs taken at room temperature. After comparing the simulated liquid nitrogen shock tests (which InSb IRFPAs experience), with its fabrication process, we can infer that the square checkerboard buckling pattern appearing in the top surface of InSb IRFPAs originates from the residual stress and strain generated in the process of insufficient cures. And the deformation amplitude decreases with decreasing temperature of InSb IRFPAs in the nitrogen liquid shock tests. At 77 K, the deformation amplitude reduces to zero. This state corresponds to our assumption, that the accumulated stress and strain disappears. When the temperature of InSb IRFPAs increases from 77 K to room temperature, the square checkerboard buckling pattern will reappear in the top surface of InSb IRFPAs. These findings are beneficial to the optimization of the structure of InSb IRFPAs and to the improvement of the number of thermal cycling experienced by InSb IRFPA without cracks generated from liquid nitrogen shock tests.
Phase separation of bilayered perovskite manganite (La1-xGdx)4/3Sr5/3Mn2 O7 (x=0, 0.05)
Authors: Xiang Jun-You  , Wang Zhi-Guo  , Xu Bao  , Sun Yun-Bin  , Wu Hong-Ye  , Zhao Jian-Jun  , Lu Yi  ,   Department of Physics, Inner Mongolia Key Laboratory of Magnetism and Magnetic Materials, Baotou 014030, China
Published: December 2020

La1-xGdx)4/3Sr5/3Mn2 O7 (x=0, 0.05) polycrystalline samples have been prepared by solid state reaction method, and the phase separation phenomena in this samples are investigated by measuring the magnetization-temperature (M-T) curve, electron spin resonance (ESR) curve and resistivity-temperature (-T) curve. For both samples, experimental results suggest there exists competition between ferromagnetic and antiferromagnetic interactions in low temperature range, which reflects a characteristic of cluster spin glass. A Griffiths-like phase is observed in temperature ranges 125375 K and 100375 K for x=0 sample and x=0.05 sample, respectively. It is found that doping contributes to the decrease of three-dimensional long-range ferromagnetic ordering temperature (from Tc03D 125 K for x=0 to Tc13D 100 K for x=0.05), but has no obvious effect on the Griffiths-like temperature (TG 375 K). Above TG 375 K, a pure paramagnetic phase appears in both samples. The -T curves reveal two insulator-metal transitions in the entire temperature range for x=0 sample, which is caused by coexistence of the two phases in perovskite manganese oxides. For x=0.05 sample, however, there exhibits a single insulator-metal transition, indicating that doping can hinder the coexistence phenomenon. It can be seen from the fitted -T curves that the electron conduction mechanism in high temperature range is in accordance with the three-dimensional variable range of hopping conduction.
Magnetic properties of the Cu-doped ZnO：experiments and theory
Authors: Wang Feng  , Lin Wen  , Wang Li-Zi  , Ge Yong-Ming  , Zhang Xiao-Ting  , Lin Hai-Rong  , Huang Wei-Wei  , Huang Jun-Qin  , W. Cao  ,   Physics and Information Engineering School, Quanzhou Normal University, Quanzhou 362000, China;,   Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014, Finland
Published: December 2020

Cux Zn1-xO were synthesized via the solid-state reaction route. Ferromagnetism was detected when the Cu percentage was bigger than 3%. The compounds were found to be the N-type semiconductors with a carrier concentration of 1015 cm-3. The DFT+U method was employed to calculate the magnetic exchange coupling of the Cu2+O2-Cu2+, Cu2+VoCu2+, Cu2+Vo+Cu2+, Cu2+Vo++Cu2+ in the CuZnO system, where Vo denoted the vacancy of oxygen. Different bound charge transfer schemes between the Vo and Cu2+ ions were revealed. The origin of the ferromagnetism was determined within the framework of the Cu2+Vo++Cu2+ bound magnetic polarons.
Near ultraviolet luminescence characteristics of ZnO nanoparticle film
Authors: Gao Song  , Zhao Su-Ling  , Xu Zheng  , Yang Yi-Fan  , Liu Zhi-Min  , Xie Xiao-Yi  ,   Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University), Ministry of Education; Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

In this paper, ZnO nanoparticle film is synthesized by using a sol-gel method. Then ITO/ZnO nanoparticles/MEH-PPV/LiF/Al heterostructure devices are fabricated. Next, the emission spectra and electrical properties of the devices are measured for different thickness of the ZnO nanoparticle films. Under DC bias, ultraviolet (UV) electroluminescence (EL) from ZnO band edge emission is observed. When the voltage is higher than 12 V, the UV electroluminescence at 390 nm from ZnO band edge emission can be observed clearly. The EL mechanisms are discussed in terms of carrier tunneling process.
A flexible microstructure based on graphene for harvesting weak energy
Authors: Lou Li-Fei  , Pan Qing-Biao  , Wu Zhi-Hua  ,   School of Microelectronics, Xidian University, Xi'an 710071, China
Published: December 2020

A novel microstructure of flexible substrate/graphene/ZnO nanowires/graphene multilayer film for harvesting weak energy is for the first time presented as far as we know in this paper. First, the design of this microstructure and its operational principle is discussed theoretically. Next, we study the key technology in the preparation process of this microstructure and carry out the whole preparation process. Finally, the microstructure is successfully achieved and tested. Results show that the output voltage of the microstructure can be up to several hundreds of millivolt. In a word, the theoretical and experimental research of this microstructure provides a basis for self-powered micro-nano systems, and is significant to the practical development of the integrated micro-nano systems.
Analysis of cascading dynamics in complex networks with an emergency recovery mechanism
Authors: Li Zhao  , Guo Yan-Hui  , Xu Guo-Ai  , Hu Zheng-Ming  ,   Information Security Center, Beijing University of Posts and Telecommunications; National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

A model of cascading failures in complex networks with an emergency recovery mechanism is proposed in this paper, and the cascading dynamics is investigated by running the proposed model on nearest-neighbor coupled network, Erdos-Renyi random graph network, Watts-Strogatz small-world network and Barabasi-Albert scale-free network respectively. New concepts in emergency recovery mechanism and the efficiency of networks are defined. And the effects of the parameters on the network efficiency and failure rate are investigated. Results demonstrate that the increase of the emergency recovery probability would reduce the network efficiency decreasing speed and the failure rate growing speed, and also improve the resilience of the network. And the greater the load capacity of the nodes in the network, the slower the speeds of network efficiency reducing and failure rate growing. Meanwhile, with the decrease of the overload node failure probability, the reducing speed of network efficiency and the growing speed of failure rate would reduce gradually. Furthermore, the changes of the network efficiency and failure rate during the process of cascading failures in different network topologies are analyzed. It is found that the rise of the heterogeneity of degree distribution increases the reducing speed of network efficiency and the growing speed of failure rate. All these results can help analyze the cascading dynamics in complex networks with an emergency recovery mechanism, and may provide a guidance for the controling of cascading failures and protecting against them in real-life complex networks.
A complex network evolution model for network growth promoted by information transmission
Authors: Liu Shu-Xin  , Ji Xin-Sheng  , Liu Cai-Xia  , Guo Hong  ,   National Digital Switching System Engineering and Technological R&D Center, Zhengzhou 450002, China;,   Institute of Information System Engineering, Information Engineering University of PLA, Zhengzhou 450002, China
Published: December 2020

In many real complex networks, information transmission occurs all the time. To study the effects of information transmission on the complex network evolution, we propose a new model for network growth promoted by the information transmission. The model includes three major steps: (i) New links attached to the nodes on the information transmission path, whose source point is chosen preferentially; (ii) the first link of the new node attached to the nodes in the local-world; (iii) other links of the new node attached to the nodes on the information transmission path, whose source point is the new node. The process of information transmission is simulated by self-avoiding random walk, and by considering the local information including its degree and distance; selective connection is established between the nodes on the information transmission path. Theoretical analysis and numerical simulation results show that the proposed model can not only reproduce small-world and scale-free network characteristics, but also indicate that shift power-law distribution and truncated power law function may form for different parameters which have some non-power-law features, such as exponential cutoff, and saturation for small variables. Moreover, in our model, the clustering coefficient is tunable without changing the degree distribution, and the model can also construct a network with assortative or disassortative mixed pattern.
Efficient simulation of three-dimensional marine controlled-source electromagnetic response in anisotropic formation by means of coupled potential finite volume method
Authors: Zhou Jian-Mei  , Zhang Ye  , Wang Hong-Nian  , Yang Shou-Wen  , Yin Chang-Chun  ,   College of Physics, Jilin University, Changchun 130012, China;,   School of Science, Changchun University of Science and Technology, Changchun 130022, China;,   College of Geo-exploration Science and Technology, Jilin University, Changchun 130026, China
Published: December 2020

A coupled potential finite volume method for simulation of three-dimensional marine controlled-source electromagnetic (CSEM) response in anisotropic formation is developed. To circumvent ill-conditioning and convergence problems, Maxwell's equations are reformulated into coupled scalar-vector potentials with Coulomb gauge and its complement by applying a Helmholtz decomposition to the electric field. Yee's staggered girds, finite volume averaging and interpolation techniques are used to make the Helmholtz equations discrete. The resulting sparse and complex linear system in large-scale models is solved by a direct solver PARDISO. In order to improve the accuracy of the near field results without significantly reducing the computational efficiency, a method using difference fields is proposed to reduce the source singularity effect of anisotropic formation. The anisotropic modeling examples show that marine CSEM response is predominantly sensitive to reservoir vertical resistivity, not to reservoir horizontal resistivity, provided that the reservoir are thin and high-resistive; but the marine CSEM response is sensitive to both horizontal and vertical resistivity of the overburden on top of the reservoir.
Influences of the system symmetry and memory on the transport behavior of Brownian motor
Authors: Wang Fei  , Xie Tian-Ting  , Deng Cui  , Luo Mao-Kang  ,   College of Mathematics, Sichuan University, Chengdu 610065, China;,   Science and Technology on Electronic Information Control Laboratory, Chengdu 610036, China;,   Southwest Institute of Technical Physics, Chengdu 610041, China
Published: December 2020

Based on the research on transport phenomenon of fractional Brownian motor, a systematic parameter (i.e. symmetry parameter) which describes the asymmetry of the periodic potential field is introduced, and the influences of the symmetry parameter and the memory parameter (i.e. the fractional order) on the transport behavior are also investigated. The numerical results show that the combined effect of fractional order and symmetry parameter can result in the reverse flow of Brownian particle's transport, and the fractional order corresponding to the maximal averaged velocity is irrelevant to the frequency of the external periodic force, but it will still increase monotonically as the symmetry parameter increases.
Spatiotemporally asymmetric fractionalLangevin-like ratchet
Authors: Zhou Xing-Wang  , Lin Li-Feng  , Ma Hong  , Luo Mao-Kang  ,   College of Mathematics, Sichuan University, Chengdu 610064, China;,   College of Computer and Information, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Published: December 2020

In this paper, a spatiotemporally asymmetric fractional Langevin-like ratchet is constructed for the operation of a one-dimensional linear molecular motor subjected to both temporally asymmetric unbiased Langevin-like noise generated by the Logistic mapping and spatially asymmetric periodic potential. In this ratchet, the Langevin-like noise is used to describe fluctuations of intracellular surrounding, and the fractional order is responsible for the effect of the non-ideal intracellular surrounding. Then, by deducing the corresponding discrete mapping, dependance of ratchet effect on parameters are numerically investigated. Numerical results show that both the temporal asymmetry of noise and the spatial asymmetry of potential are crucial to the directed-transport of the ratchet, and competitive spatially asymmetric potential can even reverse the unidirected transport generated by the temporally asymmetric noise at suitable parameters.
Adaptive stochastic resonance method based on quantum particle swarm optimization
Authors: Li Yi-Bo  , Zhang Bo-Lin  , Liu Zi-Xin  , Zhang Zhen-Yu  ,   State Key Laboratory of Precision Measuring Technology and Instrument, Tianjin University, Tianjin 300072, China;,   School of Electronic and Information Engineering, Tianjin University, Tianjin 300072, China;,   International School of Software, Wuhan University, Wuhan 430072, China
Published: December 2020

In order to enhance the usefulness of the theory of stochastic resonance in the areas of weak signal detection, a new method based on quantum particle swarm optimization is proposed to conquer with the problem of adaptive stochastic resonance. First, the problem of adaptive stochastic resonance is converted into the problem of multi-parameter optimization. Then simulation experiments are conducted respectively under a Langevin system and Duffing oscillator system. At the same time, Point detection method is chosen as the comparative test in the Langevin system. While in the Duffing system, the optimization results are compared with those from the Langevin system directly. Results show that the method based on quantum particle swarm optimization is obviously superior to the point detection method and optimization result in the Duffing oscillator is better than that from Langevin system under the same condition. Besides, it is also found that the lower the SNR of input signal, the more effective the quantum particle swarm optimization is. Finally, the regularity of optimization results of the stochastic resonance system parameters is summarized.
Analysis of the Willis chaotic system and thecontrol of random phase
Authors: Gu Yuan-Feng  , Xiao Jian  ,   College of Mathematics and Statistics, Chongqing University, Chongqing 401331, China
Published: December 2020

In this paper, we investigate the influence of each parameter of Willis chaotic system on the system, and calculate the Lyapunov exponent of Willis chaotic system containing chaotic phase. The analysis of the influence of chaotic phase on the Willis system shows that the random phase can control chaos. We also analyze the differences in intensity among various noises. Finally, the effectiveness of the above method is verified through the analysis of integrating phase portraits and Poincaré surface.
Grid-controlled emission source for space X-ray communication
Authors: Ma Xiao-Fei  , Zhao Bao-Sheng  , Sheng Li-Zhi  , Liu Yong-An  , Liu Duo  , Deng Ning-Qin  ,   State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China;,   University of Chinese Academy of Sciences, Beijing 100049, China;,   School of Information Science and Technology, Tsinghua University, Beijing 100084, China
Published: December 2020

Using X-ray as carrier signal to realize the high rate information transmission in a distant space is attracting the attention of researchers. The development of this technology has a positive significance for broadening the scope of use of the electromagnetic spectrum. In this paper, the novel grid control X-ray source, which consists of a traditional X-ray tube and a signal control grid, is designed to meet the requirements of X-ray communication in the simulation vacuum experimental system by means of three-dimensional electromagnetic simulation software CST particle studio. The tube potential distribution, electron trajectory, actual focal spot and the number of electrons at the anode are simulated by the computer simulation software. It works by changing the grid voltage to control the X-ray pulse emission. The data of the simulation are as follows. The actual focal spot size is 0.4 mm×4 mm, the effective gate-on voltage is 0 V, and the gate-off voltage is-10 V. X-ray tube grid-controlled characteristics are tested in experiment. The test results are well consistent with the simulation results. Finally, the digital signal transmission is successfully implemented in the X-ray vacuum experiment system.
β--decay half-lives for waiting point nucleiaround N=82
Authors: Chen Ze  , Zhang Xiao-Ping  , Yang Hong-Ying  , Zheng Qiang  , Chen Na-Na  , Zhi Qi-Jun  ,   School of Physics and Electronic Sciences, Guizhou Normal University, Guiyang 550001, China;,   School of Physics, Nanjing University, Nanjing 210008, China;,   Space Science Institute, Macau University of Science and Technology, Macau 519020, China;,   Center for Astronomy Research and Education, Guizhou Normal University, Guiyang 550001, China;,   School of Mathematics and Computer Science, Guizhou Normal University, Guiyang 550001, China
Published: December 2020

Based on the exponential formula of β--decay half-lives for nuclei far from stable line, the half-lives of nuclei around N=82 (R-process waiting point nuclei) are calculated. The results are compared with recent theoretical and experimental data. It is shown that compared with the complicated and time-consuming microscopic calculation, the exponential formula including the shell effect can give the results of β--decay half-lives for R-process waiting point nuclei quicker and better. The results can be used as reliable inputs for the network calculation for nuclei synthesis in cosmos.
Isomer 178m2Hf prepared by using α particles to bombard a natural ytterbium target and analysis ofhigh purity Ge γ spectrum
Authors: Tu Xiao-Qing  , Zhou Rong  , Dai Fei  , Yang Tian-Li  , Yang Chao-Wen  ,   College of Physical Science and Technology, Sichuan University, Chengdu 610064, China;,   Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

178m2Hf isomer is of great importance in science and application. Using natural ytterbium bombarded by α particles to produce 178m2Hf through 176Yb (α, 2n) 178m2Hf nuclear reaction may be a low-cost way. Three natural ytterbium targets of about 200 μ m in thickness are fabricated by magnetron sputtering of natural Yb onto copper substrates, and then irradiated with 30 MeV, 50 μ A α beam in the CS-30 cyclotron for about 50 hours. After cooling, Hf is isolated from one target through chemical isolation. Gamma spectra of two targets and the isolated Hf sample are measured with high purity Ge detector. Overlapping peaks of the complex spectrum are separated by using Gaussian multi-peak fitting. The content of 178m2Hf nuclide is identified to be 1012 orders of magnitude in each target, and 1011 orders of magnitude in the purified sample from chemical isolation. The content values of other radioactive nuclides (175Hf, 172Lu, 172Hf, 177Lu, 173Lu ) in targets are also measured.
Determination of 232Th(n, γ) reaction rate induced by D-T neutrons in one-dimensional alternate depleted uranium/polyethylene shells
Authors: Yang Yi-Wei  , Liu Rong  , Jiang Li  , Lu Xin-Xin  , Wang Mei  , Yan Xiao-Song  ,   Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China;,   Key Laboratory of Particle and Radiation Imaging of Ministry of Education, Tsinghua University, Beijing 100084, China;,   Department of Engineering Physics, Tsinghua University, Beijing 100084, China
Published: December 2020

A series of neutron integral fundamental researches of thorium nuclear data in set-ups containing thorium samples is carried out. One-dimensional alternate depleted uranium/polyethylene shells containing thorium samples are constructed by referring to the conceptual design of fusion-fission hybrid reactor, where a D-T neutron source driven by accelerator is used to simulate the fusion core of the reactor. 232Th (n, γ ) reaction rates in samples located at different positions in the shells are measured in 5% uncertainty by using activated thorium sample decay γ-ray off-line measurement technique. The results show that the moderation of polyethylene to 14.1 MeV neutron will efficiently increase the capture rate of thorium, and the depleted uranium is also conducible to this increase obviously. The comparison between our measured data and the results available from mainstream nuclear data bank shows that the calculation results from ENDF/B-VI.6 and JENDL-3.3 are around 6% higher than the experimental results, while the newer ENDF/B-VII.0 will achieve better results, around 4% higher than the experimental results. We recommend the ENDF/B-VII.0 to be used in one-dimensional alternate depleted uranium/polyethylene shells related conceptual design when calculating the 232Th (n, γ) reaction rate.
Correlation of Eu L X-ray yield with kinetic energy based on the impact of Eu20+ on solid Au target
Authors: Li Yao-Zong  , Zhang Xiao-An  , Liang Chang-Hui  , Zhao Yong-Tao  , Zhou Xian-Ming  ,   Ion Beam and Optical Physical Laboratory, Xianyang Normal University, Xianyang 712000, China;,   Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
Published: December 2020

The EuLX-ray emission from the impact of Eu20+ ions of 3.0-6.0 MeV kinetic energies on Au target is detected. We obtain the experimental relationship of single ion X-ray yield with kinetic energy of ions. Considering the ion stopping in the target, the yield of the single ionLshell holes produced by the collision of Eu20+ ion with Au atom is calculated. According to the fluorescence yield of EuLshell holes, we deduce the theoretical relationship of X-ray yields with kinetic energy of ion. The results show that the theoretical curve is well consistent with the experimental data.
Newmark algorithm in the finite-difference time-domain analysis of ferrite magnetized in an arbitrary direction
Authors: Wang Fei  , Wei Bing  , Yang Qian  , Li Lin-Qian  ,   School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, China
Published: December 2020

The permeability tensor of saturated magnetized ferrite in frequency domain in the laboratory coordinate system is obtained by using the transformation matrix between the principal and laboratory system. The constitutive relation in time domain, which is a kind of second order differential equation, is derived by employing the transformation from the frequency domain jω to time domain ∂/∂t and solved by utilizing the Newmark algorithm. Consequently, a Newmark finite-difference time-domain method is proposed to deal with the problem of electromagnetic scattering by ferrite which is subjected to an external magnetic field in an arbitrary direction. The electromagnetic scattering by a magnetized ferrite layer and a sphere is simulated, and the numerical results demonstrate the validity and feasibility of the proposed method.
Propagation characteristics of small-bandwidth pulsed beams with smoothing by spectral dispersion in high power laser system
Authors: Liu Lan-Qin  , Zhang Ying  , Geng Yuan-Chao  , Wang Wen-Yi  , Zhu Qi-Hua  , Jing Feng  , Wei Xiao-Feng  , Huang Wan-Qing  ,   Research Center of the Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

In this paper, we numerically study the propagation characteristics through spatial filter and free space of small-bandwidth pulsed beams with smoothing by spectral dispersion (SSD) in high power solid-state laser system. The numerical simulation with time-, space-and spectrum-resolution is achieved by using laser propagation and amplification software developed by Research Center of the Laser Fusion. The graphs of corresponding time-, space-and spectrum-distribution are presented, and the propagation characteristics between the SSD and non-SSD beam are compared. Besides, the effects of some SSD parameters on the diffraction propagation are further discussed. The results can help to choose the proper beam divergence of SSD which matches with the size of the spatial filter hole, to design the appropriate modulation frequency and the color circle number and so on. Moreover, it could guide the design of the light path, especially the design of free space propagation of small-diameter laser.
Surface stochastic characteristics ofcontinuous phase plate
Authors: Lü Chen  , Zhang Rong-Zhu  ,   College of Electronics and Information Engineering, Sichuan University, Chengdu 610064, China
Published: December 2020

According to the stochastic behavior of the continuous phase plate (CPP) surface shape distribution, the autocorrelation function and the correlation length are used to analyze its surface shape characteristics. A Gaussian random distribution function is used to derive the analytic relation between the correlation length and the far-field distribution of CPP. Numerical algorithm is used to calculate the variance and the energy usage rate of CPP's far-field distribution, and also the specific influence of correlation length on far-field distribution of CPP. The conclusion is that the smaller the correlation length, the better the homogeneity of far-field distribution is, and the closer to the target spot the shape of the focal spot will be, and at the same time the higher the energy usage rate will be.
Experimental research of four-wave mixing and soliton effects in a photonic crystal fiber pumped femtosecond pulses at the wavelength located normal dispersion regime away from the zero dispersion point
Authors: Li Jian-She  , Li Shu-Guang  , Zhao Yuan-Yuan  , Han Ying  , Chen Hai-Liang  , Han Xiao-Ming  , Zhou Gui-Yao  ,   State Key Laboratory of Metastable Material Science and Technology, College of Science, Yanshan University, Qinhuangdao 066004, China;,   Key Laboratory for Special Fiber and Fiber Sensor of Hebei Province, College of Information Science and Engineering, Yanshan University, Qinhuangdao 066004, China
Published: December 2020

In this paper, we show experimentally that a pair of signal wave and idler wave bands is generated by four-wave mixing, and a pair of optical solitons and dispersion wave bands is induced by intrapulse Raman scattering and non-soliton radiation, and we also observe the power saturation phenomenon of the photonic crystal fiber (PCF) by using the incident femtosecond pulses in normal dispersion region away from the zero-dispersion wavelength of the PCF. The dispersion and nonlinear characteristics of the PCF are studied by the finite element method. The possible positions of the signal wave band and the idler wave band that is generated in the fiber satisfying the phase-matching condition are simulated by four-wave mixing phase matching, the results are in good agreement with the experimental results and show that even the pump laser pulse in the normal dispersion region can also produce the PCF four-wave mixing and optical solitons effects. In the present study it also revealed that the four-wave mixing experiment is generated by the fourth-order dispersion parameter β4, and the origins of optical solitons and dispersion wave bands generation are further explained.
Spectral phase measurement and compensation of femtosecond laser pulse based on multi-photon intra-pulse interference phase scan
Authors: Zhao Guan-Kai  , Liu Jun  , Li Ru-Xin  ,   State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

In this paper, we develop a system that can be used to measure and compensate spectral phase of femtosecond laser pulses based on the multi-photon intra-pulse interference phase scan (MIIPS). In the system, a liquid crystal spatial light modulator (LC-SLM) is used to impose phase scan on the femtosecond laser pulse, while a spectrometer is used to record the MIIPS trace. Both the LC-SLM and the spectrometer are driven by home-developed LabVIEW programs. By analyzing the MIIPS trace, we obtain the spectral phase of the pre-chirped femtosecond laser pulse with only 3-times iteration. The femtosecond laser pulse is centered at 810 nm and has a repetition of 1 kHz. The accuracy of our measurement is less than ±0.1 rad. The measured phases are compensated by the LC-SLM, then we obtain a femtosecond laser pulse which is almost in the transform limit state. The device will be useful in many fields, for example, multi-photon microscopy, pulse shaping, and femtosecond laser spectroscopy etc.
Effects of turbulent medium refractive index structure constant Cn2 on the propagation characteristics of double-half hollow Gaussian beams
Authors: Chen Xin-Yu  , Dong Yuan  , Guan Jia-Yin  , Li Shu-Tao  , Yu Yong-Ji  , Lü Yan-Fei  ,   Key Laboratory of Solid-State Laser Technology and Application of JilinProvince, Changchun University of Science and Technology, Changchun 130022, China
Published: December 2020

Based on the Rayleigh-Sommerfeld diffraction integral theory, the propagation analytical expression of double-half Gaussian hollow beams in turbulent atmosphere is derived by using the cross spectral density function, and the effects of turbulent medium refractive index structure constant Cn2 on the propagation characteristics of double half a hollow Gaussian beams are studied and the intensity distributions under the different conditions are obtained as well. The research results show that the increased Cn2 can exacerbate the near-field diffraction effects of double-half Gaussian hollow beams, which not only shortens the propagation distance of hollow beams fully evolved into the Gaussian beams, but also increases the extent of the Gaussian beam extend outward.
Study of acoustic levitation by lattice Boltzmann method
Authors: Xie Wen-Jun  , Teng Peng-Fei  ,   Key Laboratory of Space Applied Physics and Chemistry of Ministry of Education, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

The axisymmetric multiple-relaxation-time lattice Boltzmann (LB) method is used to study the acoustic levitation of a rigid disk sample in a closed cylindrical resonant chamber. The simulation results show that the resonant cavity length L is equal to 0.499λ for (001) mode, and the resonance shift δL is approximately equal to-0.9 with a disk sample located in the chamber center, which accord with the analytical results derived from linear acoustics. The LB method naturally includes the viscosity and resonance shift during the simulation of acoustic levitation force on the disk sample, which gives the results not only consistent with the theory in magnitude, but also coherent with the experiments in more details. Some of the nonlinear effects associated with acoustic levitation, such as waveform distortion, acoustic streaming, and radiation pressure, are also revealed by the LB simulation.
Generalized stochastic resonance of power function type single-well system
Authors: Ji Yuan-Dong  , Zhang Lu  , Luo Mao-Kang  ,   College of Mathematics, Sichuan University, Chengdu 610065, China
Published: December 2020

To generalize the harmonic potential of the linear random vibration system, a more general power type potential is presented, and the corresponding power function type nonlinear single-well random vibration system is obtained. The first moment of the system steady-state response and the stationary variance of the system response, which are influenced by noise strength, parameters of the potential and the periodic excitation, are studied by using the second order stochastic Runge-Kutta algorithm. The parameter b, which determines the shape of the potential, goes through b b > 2 and b=2 (harmonic potential), and it is shown that varying the noise strength, if b b=2 (harmonic potential) or b > 2, this phenomenon does not occur; varying the parameters of the potential, the first moment of the system steady-state response and the stationary variance of the system response can also be non-monotonic.
Numerical study on the heterogeneous flow inporous biofilters
Authors: Xiang Rong  , Yan Wei-Wei  , Su Zhong-Di  , Wu Jie  , Zhang Kai  , Bao Fu-Bing  ,   College of Metrology and Measurement Engineering, China Jiliang University, Hangzhou 310018, China;,   Department of Aerodynamics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Published: December 2020

Biofiltration technology has received much attention because of its effectiveness, economy and environmentally friendly property, which can filter the odors caused chiefly by H2S via the biological treatments. In this study, the lattice Boltzmann method is adopted to numerically investigate the heterogeneous flow in three porous biofilter models. The numerical results indicate that the property of porous media and the inlet flow condition have significant influence on the value of critical Rayleigh number. With the increase of Darcy number and porosity, the critical Rayleigh number will gradually decrease; however, it will steadily increase with the augment of inlet Reynolds number. The present study is helpful to provide a rational theoretical guidance for the optimized design of biofilters.