bluuebunny/crossref_metadata_2025 huggingface dataset:
Digital simulation for coherent X-ray diffractive imaging
Authors: Zhou Guang-Zhao  , Tong Ya-Jun  , Chen Can  , Ren Yu-Qi  , Wang Yu-Dan  , Xiao Ti-Qiao  ,   (1)Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China; (2)Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China;Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Phase retrieval is one of the most important steps for coherent X-ray diffractive imaging (CXDI), Which uses the oversampled far-field diffraction pattern for phase retrieval iterative algorithm in order to achieve the lost phase information. Here we used a small nonperiodic 2D digital image as the object for studying the effect of the oversampling ratio and obtained the optimum oversampling ratio of 3—7 when the iteration times was 1000. We also added random noise to the diffraction pattern to examine the applicability of this approach to real data. We found the reconstruction failed when the signal to noise ratio is less than 10. As the reconstruction process may fail when the twin image or stochastic shift appears in the reconstructed image simultaneously, we explained why these phenomena come into being, and found methods to overcome the difficulty effectively.
Theoretical study on the rotation of particles driven by Gaussian beam
Authors: Li Ji-Jun  , Han Guo-Xia  , Du Yun-Gang  , Han Yi-Ping  ,   (1)Department of Applied Physics, School of Science, Xidian University, Xi’an 710071, China; (2)Department of Applied Physics, School of Science, Xidian University, Xi’an 710071, China;Department of Physics, School of Science, Inner Mongolia University of Technology, Hohhot 010051, China; (3)Department of Physics, School of Science, Inner Mongolia University of Technology, Hohhot 010051, China
Published: December 2020

Based on the fact that the polarized beam is composed of L-photon and D-photon, the expressions of the radiation trapping forces and torques of spherical particle exerted by polarized Gaussian beam are obtained in the framework of the generalized Lorenz-Mie theory. The reasons of the two different rotations of particles driven by circularly polarized Gaussian beam are analyzed and explained in combination with the quantum properties of photon. Then numerical simulations are performed for the two kinds of torques acted on the particles by polarized Gaussian beam, and the effects on the torques and optically driven rotations of the radius, relative refractive index, absorbing coefficient of the particle and waist radius of the beam are discussed.
Field emission of carbon nanotube under atmospheric pressure
Authors: Qian Li  , Wang Yu-Quan  , Liu Liang  , Fan Shou-Shan  ,   Tsinghua-Foxconn Nanotechnology Research Center, Department of Physics, Tsinghua University, Beijing 100084, China
Published: December 2020

Field emission of carbon nanotube in different gases (for example, Air, He, Ne) under atmospheric pressure has been studied. The distance between anode and cathode was 100—200 nm. Detailed comparison has been made to characterize the field emission currents and fluctuations in various gases with different anode-cathode distances.
Effect of distribution of weight on the efficiency of weighted networks
Authors: Tian Liu  , Di Zeng-Ru  , Yao Hong  ,   (1)Department of Systems Science, School of Management, Beijing Normal University, Beijing 100875, China; (2)Department of Systems Science, School of Management, Beijing Normal University, Beijing 100875, China;Department of Economics, Maxwell School, Syracuse University, NY 13210 , US; (3)School of Science, Inner Mongolia Agricultural University, Huhhot 010018, China
Published: December 2020

Weighted networks can give more detailed description of interaction between agents of corresponding systems. Link weight also provides another way to improve the properties and functions of networks. Based on the concept of network efficiency in binary networks, in this paper, the efficiency of weighted networks with similarity or dissimilarity weight is defined. The effect of weight distribution on the network efficiency are investigated. From the initial regular network with homogeneous link weights, a method is introduced to randomize the weight distribution over the links. The results demonstrate that the random redistribution of link weight can improve the network efficiency. Moreover, exponential distribution of link weight shows more significant improvement compared with the other common distributions, such as uniform, Poisson, Gauss, and power law distributions. Meanwhile, it is also found that the total weight of the corresponding minimum spanning tree is reduced with the randomization of link weight. That means the cost of transportation is decreased with the increase of link weight heterogeneity. All these results can help us get deeper understanding about the effect of link weight on the property and function of networks.
A non-linear similarity method for season division in China
Authors: Hou Wei  , Feng Guo-Lin  , Sun Shu-Peng  , Zhang Lu  ,   (1)College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China; (2)National Climate Center, Beijing 100081, China; (3)National Climate Center, Beijing 100081, China;State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth SystemScience, Beijing Normal University, Beijing 100875, China
Published: December 2020

Using the daily observational data of temperature, pressure, relative humidity and precipitation in 752 stations of China from 1961 to 2008, three methods of division of season, i.e. Zhang’s method, non-linear similarity method and Fisher optimal dissection method are applied to different meteorological elements fields of China. Results indicate that division of season through multi-variables methods is more reasonable than single variable ones, especially in non-linear similarity method and Fisher optimal dissection method. When considering the seasonal climate transition between successive seasons, the results are in good accordance with actual observations. As a result we recommend the non-linear similarity method as a better way of season division.
A simulation experiment system for X-ray pulsar based navigation
Authors: Hu Hui-Jun  , Zhao Bao-Sheng  , Sheng Li-Zhi  , Yan Qiu-Rong  ,   (1)State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China; (2)State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China;Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

A simulation experiment system for X-ray pulsar based navigation is setup in order to study the key technologies of X-ray pulsar navigation. The system consists of X-ray pulsar source generator, super sensitive X-ray photon counting detector, charge sensitive amplifier, shaping amplifier, time measurement, X-ray pulse profile reconstruction and pulse time of arrival (TOA) measurement. The system can simulate the X-ray pulsar source with different intensities, period and pulse profile. The TOA of individual X-ray photon is recorded, the pulse profile is reconstructed with these data. And by comparing the measured pulse profile with the standard pulse profile of the X-ray pulsar source generator, the pulse TOA is calculated. The construction and the principle of the simulation experiment system are introduced and experiment results are presented.
Consensus problem of coupled autonomousagents with time delays
Authors: Liu Cheng-Lin  , Liu Fei  ,   Institute of Automation,Jiangnan University,Wuxi 214122,China
Published: December 2020

Coupled consensus problem of multiple autonomous agents with communication delay and input delay is investigated. Based on the frequency-domain analysis,sufficient conditions for the first-order and second-order agents are obtained respectively. The conditions are dependent on the input delay,the communication delay and the control parameters. Simulations illustrate the correctness of the results.
The solution for a class of nonlinear solitary waves in dusty plasma
Authors: Mo Jia-Qi  ,   Department of Mathemtics, Anhui Normal University, Wuhu 241000, China)(Division of Computational Science, E-Institutes of Shanghai Universities at SJTU, Shanghai 200240, China
Published: December 2020

A class of nonlinear solitary waves in dusty plasma is considered. Firstly, a variational iteration is constructed. Then the initial approximate solution is determined. Finally, using the method of the variational iteration, each degree approximation for corresponding model is found.
The periodic solutions of a delayed sea-air oscillator coupling model for the ENSO
Authors: Wang Wen  , Xu Yan  , Lu Shi-Ping  ,   College of Mathematics and Computer Science, Anhui Normal University, Wuhu 241003, China
Published: December 2020

Using Mawhin's continuation theorem, the existence of periodic solutions for a class of nonlinear problem are first discussed, and then by using it, the problem of periodic solutions for a delayed sea-air oscillator coupling model for the ENSO is investigated. A new result on the existence of periodic solutions to the model is obtained.
A heterogeneous computing algorithm for two-dimensional unstable manifolds of time-continuous systems
Authors: Li Qing-Du  , Tan Yu-Ling  , Yang Fang-Yan  ,   (1)Institute for Nonlinear Systems, Chongqing Univ. Posts and Telecommunications, Chongqing 400065, China; (2)Key Laboratory of Network Control & Intelligent Instrument of Ministry of Education, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
Published: December 2020

Two-dimensional manifolds usually contain many nonlinear behaviors in complicate structures, which implies that much numerical calculation must be done during computing. Therefore, how to accomplish the work efficiently is a key problem. Since today’s computers tend to heterogeneous platforms including multi-core CPUs and general purpose GPUs, this paper proposes a fast manifold computing algorithm, which is not only of high precision and versatility, but also very suited to the new generation of computers. The algorithm contains two kinds of computation: extending trajectories and generating triangles. The former is large and simple, which is suitable for GPU; the later is small and complicate, which is suitable for CPU. The computation for the stable manifold of the Lorenz system at the origin shows that this algorithm ensures the best performance of heterogeneous platforms and improve the computing speed greatly.
A new three-mode entangled state representation generated by beamsplitter and polarizer
Authors: Wang Shu-Jing  , Ma Shan-Jun  ,   College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, China
Published: December 2020

We constructed a new three-mode entangled state representation in the three-mode Fock space, which is complete and can make up a new quantum representation. This state can be generated experimentally by combining beamsplitter with polarizer. The entanglement properties are analyzed by obtaining its Schmidt decomposition. As an important application of this state, we consider a single-mode state teleportation by using this new state as a quantum channel, and present the corresponding teleportation scheme.
Optimization criterion of potential for trappedweakly interacting Bose gas
Authors: Yuan Du-Qi  ,   Department of physics and Information Technology, Baoji University of Science and Arts, Baoji 721016, China
Published: December 2020

Based on Bose-Einstein condensation in minimized momentum state, the optimization criterion of potential is studied for trapped weakly interacting Bose gas according to Thomas-Fermi approximation. A criterion for the validity of potential and the limited atom number loaded in a power law attractive potential well for ultra-cold weakly interacting Bose atom gas is derived. The criterion gives the required potential field strength when the loaded atom number is fixed, or the limited atom number when the potential field strength is given, and then, the best ranges of potential field strength are obtained, for attractive interaction and repulsive interaction, respectively.
Analytical analysis of periodic solution and its stability in Josephson junction
Authors: Zhang Li-Sen  , Cai Li  , Feng Chao-Wen  ,   School of Science, Air Force Engineering University, Xi’ an 710051, China
Published: December 2020

Analytical expressions of periodic solutions in rf-biased resistively-capacitively-shunted Josephson junction were derived by incremental harmonic balance method, and the stability of the periodic solutions was investigated using Floquet theory. We fownd that while the system is in stable periodic states, plentiful unstable periodic orbits still exist in the system. Critical parameter values for which the stable periodic solutions of the system lose their stability are obtained and the type of bifurcation is determined by computing the Floquet multipliers. We have also theoretically confirmed the period-doubling-route to chaos with increasing amplitude of driving current, which acts as the control parameter in the system. The results from analytical analysis coincide with that from numerical simulation.
The numerical study on the effect of the earlyafterdepolarization on spiral wavesin discrete excitable media
Authors: Wei Hai-Ming  , Tang Guo-Ning  ,   College of Physics and Technology,Guangxi Normal University,Guilin 541004,China
Published: December 2020

The early afterdepolarization (EAP) behavior is introduced into the Greeberg-Hasting model of discrete excitable medium through considering that some of the refractory states can be excited. The effect of the EAP on spiral wave is studied. The numerical results show that the EAP has significant influences on spiral waves when the related parameters are suitably chosen. These influences include that the EAP causes spiral wave drifting and meandering,and spiral breakup. The pattern of spiral wave is distorted. The spiral wave varies alternately between those with thick and thin arms. The period of spiral wave alters alternately between two values. The EAP induces the transition from stable spiral wave to breathing spiral wave or antispiral wave. When the excitation threshold of refractory states is very high,the EAP has no affect on the spiral wave. The EAP induced phenomena are briefly discussed.
A novel three-dimensional autonomous chaotic system
Authors: Feng Chao-Wen  , Cai Li  , Kang Qiang  , Zhang Li-Sen  ,   College of Science, Air Force Engineering University, Xi’an, Shaanxi 710051, China
Published: December 2020

Based on the study of Chua’s circuit, a novel chaotic system is reported. Basic dynamical properties of the new system are further investigated via theoretical analysis and numerical simulation, including Lyapunov exponent, Lyapunov dimension, portrait diagrams, Lyapunov exponent spectrum, bifurcation diagrams, Poincaré mapping and power spectrum. Finally, an electronic circuit is designed by the Orcad-PSpice softeware to implement the new system. The investigation results show that the new chaotic system has broad parameter regions, an maximum Lyapunov exponent approaching one, and is not topologically equivalent to Chua’s circuit. It also shows a good agreement between numerical simulation and circuit experimental simulation, which proves the existence and physical realizability of the new chaotic system.
Density functional theory study on the structure and electronicproperties of Aun Sc3 (n =1—7) clusters
Authors: Ge Gui-Xian  , Yan Hong-Xia  , Jing Qun  , Zhang Jian-Jun  ,   Key Laboratory of Ecophysics and Department of Physics, Normal College, Shihezi University, Shehezi 832003, China
Published: December 2020

Geometric structures of Aun Sc3 (n=1—7) clusters are optimized by using the generalized gradient approximation (GGA) density functional theory. Energy, vibrational frequency and electronic properties have been calculated. The 3D structure of AunSc appears earlier than that of Aun. The triangle bipyramid structure of Au2Sc3 is a building block for larger AunSc3 of n≤7. Furthermore, the investigation on the second-order difference shows that the clusters with even Au atoms have enhanced stabilities, which may be due to the electron shell effects.
The research of motorial characteristic of sodiumatoms in standing wave field
Authors: Zhang Wen-Tao  , Zhu Bao-Hua  , Xiong Xian-Ming  ,   School of Electronic Engineering and Automation, Guilin University of Electronic and Technology Guilin University of Electronic and Technology, Guilin 541004, China
Published: December 2020

Direct write atom lithography is a new technique in which resonant light is used to pattern an atomic beam and the nanostructures are formed when the atoms deposit on the substrate. The motion of sodium atoms in standing wave filed is discussed. Based on the semi-classical model, this paper analyses the motion equation of sodium atom in the laser standing wave field, and then gets the trajectory of the atoms in the standing wave field by analytical simulation for different longitudinal and transverse velocities. The simulative results show that the FWHM width of stripes was 2.78 nm and the contrast was 38.5 ∶1 for the optimal longitudinal velocity, while that of the stripes was 29.1 nm and the contrast was 15 ∶1 for non-optimal longitudinal velocities. At the same time, the results show that the FWHM width of stripes was 4.2 nm and the contrast was 20 ∶1 when the divergence of atomic beam was 0.15 mrad. Whereas, the stripes presented Multi-peaked configuration and the quality deteriorated with the divergence of atomic beam increased to 1.5 mrad.
Isolated intense 39 attosecond pulse generatedby adding a harmonic pulse
Authors: Chen Yang  , Chen Ji-Gen  , Yang Yu-Jun  ,   (1)College of Physics and Electronic Engineering, Taizhou University, Taizhou 318000, China; (2)Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
Published: December 2020

A scheme to efficiently generate a broadband short attosecond pulse is presented by using intense multi-cycle 800 nm laser in combination with its 27th harmonic (H27) laser pulse. It is shown that the electronic dynamics can be efficiently controlled by the 1 fs H27 laser. Setting the H27 laser to the multi-cycle 800 nm laser at a proper time, we can control most of the ionizations to occur at half the optical cycle, and the short quantum path can be picked out, thus the harmonic plateau is heightened four orders of magnitude compared with the case of using the fundamental laser alone. Furthermore, a harmonic supercontinuum spectrum with a bandwidth of 108 eV is produced. By superposing the 140th-210th harmonics in the continuous region, an intense isolated pulse with the duration of 39 as is straightforwardly obtained. Using this method, the bandwidth of the continuum spectrum is 2 times wider, the intensity of the attosecond pulse is greater, and the duration of the attosecond pulse is shorter, in contrast to the scheme proposed in Ref. [7], which added the ultraviolet attosecond pulse to a few-cycle 800 nm laser.
The wavelength dependence of high-order harmonic generationand attosecond pulses from atom in infrared laser field
Authors: Cheng Chun-Zhi  , Zhou Xiao-Xin  , Li Peng-Cheng  ,   College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Published: December 2020

Basing on the strong-field approximation, we study high harmonic generation of hydrogen atom exposed to the long wavelength infrared laser field, and analyze the wavelength dependence of conversion efficiency of high-order harmonic generation near the cut-off position. It is found that high-order harmonic yield is much lower near cut-off than in the beginning of the plateau of the harmonic generation, but the width of the attosecond pulse is narrowed with increasing wavelength.
Prediction of thermophysical properties of pure noble gases
Authors: Song Bo  , Wang Xiao-Po  , Wu Jiang-Tao  , Liu Zhi-Gang  ,   State Key Laboratory of Multiphase Flow in Power Engineering, Xian Jiaotong University, Xian 710049, China
Published: December 2020

The thermophysical properties of pure helium-4, neon, argon, krypton and xenon are calculated using ab initio potentials of kinetic theory over the temperature range from 50 to 5000 K at zero-density, including the second virial coefficient, thermal diffusion coefficient and thermal diffusion factor. Comparing with results obtained by empirical potentials, the results of present work are in better agreement with experimental data and recommended values of REFPROP 8.0.
Investigation on the reconstruction of roughsurface with hybrid method
Authors: Liang Yu  , Guo Li-Xin  , Wang Rui  ,   School of Science, Xidian University, Xian 710071, China
Published: December 2020

Based on the Desantos spectral formalism, using the hybrid method that combines the numerical and approximate algorithms, the reconstruction problem for the one-dimensional rough surface is investigated. For the direct problem, the scattering data is obtained by the numerical algorithm—the method of moments (MOM). For the inverse problem, the profile of rough surface with different roughness is reconstructed by two approximate algorithms—the small perturbation approximation (SPA) and the Kirchhoff approximation (KA) combined with the method of moments. Taking the Gaussian rough surface for example, the numerical results of reconstructed rough surface with different roughness are presented for the hybrid method, and the data are compared and analyzed.
Sequence images hiding technique of three-dimensional object based on principal component analysis in wavelet domain
Authors: Shuai Wen-Juan  , Feng Shao-Tong  , Nie Shou-Ping  , Zhu Zhu-Qing  ,   Jiangsu Province Key Laboratory for Opto-electronic Technology Nanjing Normal University, Nanjing 210097, China
Published: December 2020

In order to hide sequence images of 3D object in a carrying image, eigenimages are obtained by using principal component analysis method. Wavelet coefficients of eigenimages are embedded into the wavelet domain of the carrying image. Based on the relationship of extracted eigenimages and coefficients, a series of images are reconstructed. The proposed method does not store the object images directly, but store the eigenimages which contain information of the 3D object. The experimental results show that the features of 3D object are effectively embedded into the carrying image, and the proposed algorithm has a high capacity.
Micro-nano-optical machine system tunable wavelength vertical cavity surface emitting lasers with wide tunable range
Authors: Guan Bao-Lu  , Zhang Jing-Lan  , Ren Xiu-Juan  , Guo Shuai  , Li Shuo  , Chuai Dong-Xu  , Guo Xia  , Shen Guang-Di  ,   Key Laboratory of Opto-electronics Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China
Published: December 2020

The stucture of tunable vertical cavity surface emitting laser is obtained based on the micro-nano-mechanical technology. The DBR reflector with Al0.8Ga0.2As sacrificial layer consisted the micro-nano reflector systerm, which combines with the multi-well active region coupled structure. In addition, the structure of micro-nano-optical machine system is not only the DBR reflector, but also serves to tune the wavelength of lasing by the electrostatic force. Good laser characteristics are obtained with continuous tuning ranges over 18.8 nm near 968.8 to 950 nm for 0—7 V tuning bias.
Superresolution in adaptive optics confocal scanning laser ophthalmoscope
Authors: Lu Jing  , Li Hao  , He Yi  , Shi Guo-Hua  , Zhang Yu-Dong  ,   (1)Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209,China; (2)Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209,China;The Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu 610209,China
Published: December 2020

The resolution of adaptive optics confocal scanning laser ophthalmoscope is constrained by human eye’s aberration, numberical aperture and pinhole size. A super resolved adaptive optics confocal scanning laser ophthalmoscope is presented. By using adaptive optics to detect and compensate human eye’s aberration, and using optical superresolution to improve resolution which is degraded by large pinhole size, the system can achieve high resolution, real-time human retina image in vivo .
Optimization of medium and control characteristics of stimulated Brillouin scattering based on mixed media
Authors: Hasi Wu-Li-Ji  , Li Xing  , Guo Xiang-Yu  , Lu Huan-Huan  , Lü Zhi-Wei  , Lin Dian-Yang  , He Wei-Ming  , Fan Rui-Qing  ,   Institute of Opto-electronics, Harbin Institute of Technology, Harbin 150080, China)(National Key Laboratory of Science and Technology on Tunable laser, Harbin Institute of Technology Harbin 150080, China
Published: December 2020

In this paper, the optimization of medium and control characteristics of stimulated Brillouin scattering (SBS) based on mixed media is investigated. The excellent intersolubility of perfluorocarbon liquid media is analyzed and the dependence of gain coefficient, phonon lifetime and Brillouin frequency shift of HT-230/FC-72 mixed media on mixing-ratio is numerically simulated. In Countinuum’s Nd: YAG seed-injected laser system, we measured absorption coefficient, optical breakdown threshold, energy reflectivity and Stokes pulses waveform of HT-230/FC-72 mixture under different mixing-ratio. The results indicate that the mixed media not only can optimize the medium, but also can control the characteristics of SBS within a certain range.
Separate spatial soliton pairs in biased series photorefractive polymer circuit
Authors: Ji Xuan-Mang  , Jiang Qi-Chang  , Liu Jin-Song  ,   (1)College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (2)Department of Physics and Electronic Engineering, Yuncheng University, Yuncheng 044000, China
Published: December 2020

This paper presents calculations based on the idea of photorefractive polymer spatial solitons, namely, screening solitons being formed in a biased series photorefractive polymer circuit consisting of two photorefractive polymer connected electronically by electrode leads in a chain with a voltage source. A system of two coupled equations is derived under appropriate conditions for two-beam propagation in the series photorefractive polymer circuit. The existence of dark-dark, bright-dark and bright-bright photorefractive polymer soliton pairs in such a circuit is proved. In the limit in which the optical wave has a spatial extent much less than the width of the photorefractive polymer, the two solitons in dark-dark soliton pairs can affect each other’s spatial profiles and the dynamical evolution by the light-induced current. For a bright-dark soliton pair, the dark soliton can affect the other soliton by light-induced current, but the bright soliton cannot. The two solitons in bright-bright soliton pairs cannot affect each other.
Numeric simulation of the diffraction pattern of zigzag grating
Authors: Zang Hua-Ping  , Cao Lei-Feng  , Wang Chuan-Ke  , Jiang Gang  , Wei Lai  , Fan Wei  , Zhou Wei-Min  , Gu Yu-Qiu  ,   (1)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (2)National Key Laboratory of High-temperature and High-density Plasma Physics, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The zigzag grating is one of the newly proposed optical dispersive elements which has an excellent diffraction characteristics and has important applications in the spectrum measurement and analysis. The simulation results of the diffraction pattern of the zigzag grating for X ray are presented using a new numerical method based on the convolution theorem, and comparison of its diffraction pattern with those of the traditional grating and sinusoidal grating are studied. It is seen from the results that all higher order diffractions of the zigzag grating are suppressed below the level of four orders of magnitude compared with the first order diffraction, which is superior to the traditional grating, being consistent with the theoretical expectations. Moreover, the impact caused by the absorber is analyzed, which eventually confirms that the zigzag grating has perfect practical application feasibility. The conclusions provide a potential alternative for the physical design of the zigzag gating, which is expected to replace the traditional transmission grating in applications to the soft X-ray spectrum measurement.
Experimental calibration of transmission grating and theoretical calculation of diffraction efficiency
Authors: Zhao Yi-Dong  , Cui Ming-Qi  , Zheng Lei  , Han Yong  , Zhou Ke-Jin  , Ma Chen-Yan  , Shang Wan-Li  , Zhu Tuo  , Xiong Gang  , Zhao Yang  , Zhang Wen-Hai  , Yi Rong-Qing  , Kuang Long-Yu  , Cao Lei-Feng  , Gao Yu-Lin  , Yang Jia-Min  ,   (1)Institute of High Physics, Chinese Academy of Sciences, Beijing 100049, China; (2)Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Transmission grating is widely used in measurement of soft X rays. In order to measure the diffraction efficiencies of the transmission grating which is used in laser fusion, the transmission grating was calibrated on Beijing Synchrotron Radiation Facility in the energy region from 200eV to 1600eV, and the experimental results have been obtained. The model for grating efficiency simulation has been developed and calculations using a new so called 7-side quasi-trapezoidal cross section model were carried out. The results from the new model are in good agreement with the experimental data. The exact grating wire cross section is described.
A new sub-aperture stitching method of measuring special optical element
Authors: Chang Jun  , Zhang Zheng-Hui  , Wang Rui-Rui  ,   Laboratory of Optoelectronics Technology and Information System, School of Optoelectronics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

Novel conformal window can enhance the aerodynamic performance of aircraft obviously. Due to the surface complexity of these conformal windows, the measuring of conformal windows is infeasible by using the conventional optical measurement technique. In this paper, we describe a new sub-aperture stitching method for conformal measurement, and introduce the design of this technology. Based on the theory of compensation method, a compensator is designed for a 70mm aperture conformal window, of which the final residual wavefront error(RMS) is 0.0515λ(λ=632.8nm).
Simulation of a metamaterial beam for mechanical wave absorption
Authors: Lin Guo-Chang  , Sun Hong-Wei  , Tan Hui-Feng  , Du Xing-Wen  ,   Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

In this paper, we present a metamaterial beam consisting of a uniform isotropic beam with many small mass-spring systems serving as mechanical wave absorbers. Based on the analysis of two different mass-spring systems, negative effective mass and negative effective stiffness are explained theoretically. The governing equations of a unit cell of a metamaterial beam are derived using the Hamilton’s principle. The mechanical wave absorbabilities of the following two different finite metamaterial beams are analyzed by numerical simulation:one is the bean in which mass-spring systems with linearly varying elastic coefficients are uniformly distributed, and the other is the bean in which four identical absorber subgroups composed of spring-damper subsystems with linearly varying natural frequenciesare uniformly distributed. The results reveal that the mechanical wave transmitted in the metamaterial beam is absorbed by resonating with spring-mass absorbers, which verifies the effectivity of the proposed metamaterial beam on mechanical wave absorption.
Development of shear band in a granular material in biaxial tests
Authors: Bi Zhong-Wei  , Sun Qi-Cheng  , Liu Jian-Guo  , Jin Feng  , Zhang Chu-Han  ,   State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

Granular matter is a large assemblage of dense packed particles. A granular skeleton frame is linked by grain-to-grain contacts. An external loading is usually transmitted through selective pathways from the skeleton frame, and heterogeneous force chain architecture is formed. The formation and evolution of shear band have importarit bearing to the stability of a granular assembly. In this work, the mechanical properties of granular matter under biaxial test are studied by using DEM simulations. Evolutions of stress, volumetric strain, coordination number, distribution of particle rotation and solid fractions are analyzed. The results show that within shear zone the solid fraction is smaller and the coordination number fluctuates violently, which indicates that they are unjammed, while beyond the shear band the particles are jammed. Therefore, we could say that the shear band actually corresponds to the complicated jamming transition. Three types of force chain configurations are observed under different axial strains: circle-shaped, column-shaped, both column and vortex-shaped. Such structures would be dominant to the mechanical properties of macro-mechanical properties and granular system, and pending further studies.
Centreline statistics of the small-scale turbulence of a circular jet and their dependence on high frequency noise
Authors: Xu Min-Yi  , Du Cheng  , Mi Jian-Chun  ,   State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, China
Published: December 2020

This study systematically investigates the statistics of the centreline small-scale turbulence of a circular jet issuing from a smooth contraction nozzle. Detailed velocity measurements were performed for the exit Reynolds number of Re=20100, where Re≡Ujd /ν with Uj being the exit mean velocity, d the nozzle diameter and ν the kinematic viscosity. After effectively filtering out high frequency noises, statistical properties of the small-scale turbulence were obtained appropriately; those properties include turbulence energy dissipation rate, Kolmogorov length scale, Taylor scale, turbulence Reynolds number, skewness and flatness of the velocity derivative. It is observed that these properties satisfy their self-preserving relations in the far field. It is also revealed that the small-scale turbulence reaches the self-preserving state earlier than does the large-scale motion. Besides, the smallest-scale turbulence depends least on the initial and boundary conditions and therefore behaves most universally across different flows.
Generation of attosecond X-ray pulse in the interaction between the pulses and the relativistic electrons
Authors: Yan Chun-Yan  , Zhang Qiu-Ju  , Luo Mu-Hua  ,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

The attosecond X-ray pulse which is produced by the interaction between the laser pulse and the relativistic electrons is studied in this paper. The attosecond X-ray pulse is generated by Thomson backscattering from the relativistic electrons. It also discusses the effect of the plasma parameters on the attosecond X-ray. The wavelength of attosecond X-ray pulse becomes shorter when the frequency of the laser or the velocity of the relativistic electrons increases. We obtained the "water window" X-ray by selecting the appropriate laser and plasma parameters. This paper also discusses the effect of relativistic electrons density and density grad on the translation efficiency.
The evolution of crystalline structure in the preparationof PAN-based carbon fibers studiedby whole powder pattern fitting
Authors: Sheng Yi  , Tian Hong  , Xu Yao  , Lü Chun-Xiang  , Wu Zhong-Hua  , Zhang Cai-Hong  ,   (1)Key Laboratory of carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; (2)Laboratory of Synchrotron Radiation, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Based on the Rietveld theory and Maud software, the evolution of crystalline structure of PAN-based carbon fibers was studied by investigating the different stages in the preparation of carbon fibers. The microstructure parameters of PAN fibers, oxidative fibers, and carbon fibers, including cell parameters, apparent crystal grain sizes, textural structure and micro-strain, were obtained from the named whole powder pattern fitting method for XRD result. Based on rigorus theory of crystallography, the whole powder pattern fitting treats the whole XRD powder diffraction pattern rather than individual diffraction peaks, resulting in higher credibility and precision. The results indicated that polymer chains were arranged along the axis of PAN fiber and the apparent crystallite size was about 6.4 nm. After pre-oxidation, the originally ordered structure in PAN fiber was damaged and new less-ordered cyclic ladder structure was formed in the pre-oxidized PAN fibers, while the apparent crystallite size of fiber decreased obviously. With the carbonization process, the cyclic ladder structure of per-oxidized fibers transferred into layer structure similar to that of graphite. The layers were oriented along the axis of carbonized fiber that contributed to the X-ray diffraction, which comprised the apparent crystallite grains. As the carbonization temperature increased, size of the layer structure in the direction perpendicular to fiber axis increased clearly, the preferential orientation was enhanced and the layer structure became much more ordered.
Growths of InAs/GaAs and InAs/In x Ga1-x As/GaAs nanowire heterostructures
Authors: Ye Xian  , Huang Hui  , Ren Xiao-Min  , Guo Jing-Wei  , Huang Yong-Qing  , Wang Qi  , Zhang Xia  ,   Key Laboratory of Information Photonics and Optical Communications (Ministry of Education), Beijing University of Posts and Telecommunications, Beijing 100876, China
Published: December 2020

InAs/GaAs and InAs/In xGa1-xAs/GaAs nanowire heterostructures are grown by metal organic chemical vapor deposition via Au-assistant vapor-liquid-solid mechanism. We find that the InAs nanowires grow directly on GaAs nanowires in a random way, or they grow along the sidewall of the GaAs nanowires, and thet InAs nanowires grow vertically on GaAs nanowires by using an In x Ga1-xAs (0≤x≤1) buffer segment. It can be concluded that the influences of crystal lattice mismatch and difference in interfacial energy can be eliminated by inserting a ternary compound semiconductor buffer segment, thereby improving the crystal quality and the capability to control the growth of nanowire heterostructure.
First principles calculations of interaction between an armchair-edge graphene nanoribbon and its graphite substrate
Authors: Yu Dong-Qi  , Zhang Zhao-Hui  ,   State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
Published: December 2020

Based on the density functional theory, first principles calculations have been performed to study interaction of armchair-edge graphene nanoribbons and their graphite substrates. As a result, it has been found that the interaction gives rise to deformation of the graphene nanoribbons and the graphite substrates, and the deformed graphene nanoribbons have the energy band structures with band gaps smaller than those of the isolatedones.
Characterization of the transparent n-type ZnO ceramic with lowresistivity prepared under high pressure
Authors: Qin Jie-Ming  , Zhang Ying  , Cao Jian-Ming  , Tian Li-Fei  , Dong Zhong-Wei  , Li Yue  ,   College of Materials Science and Engineering, Changchun University of Science and Technology,Changchun 130022,China
Published: December 2020

In this paper,the preparetion of transparent ZnO ceramic with with low resistivity by high pressure sintering was reported,and the problem of high resistivity and opaqueness for ZnO under atmospheric pressure sintering was solved. The ZnO ceramic of optimal photoelectronic performance with high transparency and low resistivity under the pressure of 5 GPa and at the temperature of 800℃ was obtained. The transmissivily is about 49%, the electronic resistivity is 0.57 Ω ·cm, the width of band gap is 3.31 eV, the carrier concentration is 8.36×1017 cm-3 and the mobility is 23 cm2 ·V-1 ·s-1. The excellent n-type electrical conductivity is attributed to the contribution of Zni and VO donor defect. The results of this work have important significance for ZnO ceramic application as photoelectronic components for ultraviolet emission.
Research on the total-dose irradiation damage effect for static random access memory-based field programmable gate array
Authors: Gao Bo  , Yu Xue-Feng  , Ren Di-Yuan  , Li Yu-Dong  , Cui Jiang-Wei  , Li Mao-Shun  , Li Ming  , Wang Yi-Yuan  ,   (1)Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China; (2)Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China;Graduate School of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In order to investigate the total-dose irradiation effects of Altera static random access memory (SRAM)-based FPGA (field programmable gate array), the irradiation response of basic cell of FPGA, i.e. the CMOS, is studied, and the relationship of the output waveform as a function of total dose has been obtained. It indicates that the output waveforms become aberrated and the peak-peak value turns to about 1/10 of the initial value as the total dose increased, resulting from the degradation of leakage current both from field oxygen and the structure; but there are relatively high and low levels left in the output waveforms. Meanwhile, the high level cant keep the already existing state and changes to the low level, and the conversion speed is accelerated with the increase of the total dose. The low level becomes larger than the initial value. As the gate-oxygen is quite thin, the rise time, fall time, and delay of the output waveforms change little with the total dose.
Effect of vacuum thermal-annealing temperatures on the microstructure and optical properties of single-phased Ag2O film
Authors: Zhang Zeng-Yuan  , Gao Xiao-Yong  , Feng Hong-Liang  , Ma Jiao-Min  , Lu Jing-Xiao  ,   Key Laboratory of Materials Physics of Ministry of Education, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450052, China
Published: December 2020

A single-phased Ag2O film was deposited on glass substrate by direct-current reactive magnetron sputtering, and was then vacuum thermally annealed at different annealing temperatures (T A) for 1 hour. Effect of the TAon the films microstructure and optical properties was investigated by X-ray diffractometry, scanning electron microscopy and spectrophotometry. The results indicate that Ag nano-scaled particles begin to appear in the annealed Ag2O film at TA= 300 ℃. The Ag content obviously increases with increasing TA, and in particular, Ag2O phase is completely transformed into Ag at T A = 475 ℃. The evolution of the films surface morphology from dense to loose indicates that the diffusion and escape of O atoms from film surface accompanied the thermal decomposition reaction of Ag2O to Ag particles during the vacuum thermal annealing. The changes of the films transmissivity, reflectivity and absorptivity with T A are attributed to the thermal decomposition of Ag2O and the films structure evolution during annealing.
First-principles study of the electronic structure and elastic property of Li x FePO4
Authors: Ru Qiang  , Hu She-Jun  , Zhao Ling-Zhi  ,   Laboratory of Quantum Information Technology, School of Physics & Telecommunication Engineering, South China Normal University, Guangzhou 510006,China
Published: December 2020

Based on density functional theory of the first-principle, the electronic structures of LiFexPO4 (x=0.0, 0.75, 1.0) are calculated. The calculated results show that Fe3d states restrained by crystalline field cannot contribute to free electrons even though Fe3d states cross the Fermi level. Meanwhile, Fe—O bond is beneficial to stabilize the alloy structure due to the p-d hybrid orbital. With lithium ion extraction, the enhanced covalent bonds appear. In LixFePO4 system, the strength of covalent bond is in the order of P—O>Fe—O>Li—O. LixFePO4 system displays brittleness of material characteristic, and the LixFePO4(x=1.0, 0.75) with lithium intercalation have stronger average bonding strength than that of FePO4.
Computer simulation of the string relaxation modes of the molecule-string model for glass transition
Authors: Zhao Xing-Yu  , Wang Li-Na  , Fan Xiao-Hui  , Zhang Li-Li  , Wei Lai  , Zhang Jin-Lu  , Huang Yi-Neng  ,   Xinjiang Laboratory of Phase Transitions and Microstructures of Condensed Matter Physics,Yili Normal University, Yining 835000, China
Published: December 2020

Monte Carlo protocols to simulate the string relaxation modes are proposed according to the Hamiltonian of the molecule-string model for glass transition. The simulated relaxation times of the 1st and 2nd modes are consistent with the predictions of the string relaxation equation of the model,thus matually verifying each other. The results show the reasonableness of not only the string relaxation equation, at least the theoretical predictions of the 1st and 2nd relaxation modes, but also the proposed simulation method, and further clarify the pictures of the molecule random energy fluctuations and jumps of the molceules in the strings, as well as provide gist and clews to the study of the multi-state molecule string relaxation dynamics and the further simulation of the complex interactions between the molecule strings.
Influence of RF power on the structure and properties of glow discharge polymer
Authors: Yan Jian-Cheng  , He Zhi-Bing  , Yang Zhi-Lin  , Zhang Ying  , Tang Yong-Jian  , Wei Jian-Jun  ,   (1)Sichuan University, Institute of Atomic and Molecular Physics, Chengdu 610065, China; (2)The Centre of Laser Fusion Research, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Using trans-2-butene and hydrogen as the precursor, the glow discharge polymer films was successfully coated on KBr discs by glow discharge polymerization at different powers. The chemical structure, thermal stability of the GDP films and the deposition rate of GDP films were characterized by the FT-IR, TG and surface profiler technology. The Results show that the deposition rate, the olefinic structure, the ratio of C/H, and the content of C C in GDP films increase with the RF power increasing. The thermal stability of GDP films fabricated at higher RF power is better.
Initial growth of SrTiO3 on Sr/Si(001) studied by scanning tunneling microscope
Authors: Qiu Yun-Fei  , Du Wen-Han  , Wang Bing  ,   Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

SrTiO3 ultra-thin film was deposited on the Sr/Si(001) surface using pulsed laser deposition (PLD) at room temperature and studied using scanning tunneling microscopy (STM). After annealing at 660 ℃ for about 60 minutes in ultrahigh vacuum (UHV), nanosize islands were formed on the Sr/Si(001) surface. High resolution STM images and dI/dV mapping of islands on Sr/Si(001) were obtained. The islands can be attributed to TiSi2 islands with C49 and C54 structures. The existence of Sr on Si is not sufficient to prevent the reaction between Si and Ti in preparation of ultra-thin SrTiO3 films.