bluuebunny/crossref_metadata_2025 huggingface dataset:
Symmetry of Birkhoffians and conserved quantity for a relativistic mechanical system
Authors: Zhang Yi  ,   College of Civil Engineering, Suzhou University of Science and Technology, Suzhou 215011, China
Published: December 2020

A new symmetry of a relativistic mechanical system is put forward, and the corresponding conserved quantity is given. The new symmetry is defined in such a way that if each solution to the differential equations of motion of a relativistic mechanical system corresponding to a set of Birkhoff's dynamical functions satisfies the differential equations of motion obtained by other set of Birkhoff's dynamical functions and vice versa, then the corresponding invariance is called a symmetry of Birkhoffians. We prove that the coefficient matrix which relates to the relativistic Birkhoff's equations obtained from two sets of Birkhoff's dynamical functions, is such that the trace of all its integer powers is a conserved quantity of the system, and therefore a theorem known for nonsingular equivalent Lagrangians presented by Currie and Saletan is extended to a relativistic Birkhoffian system. Two examples are given to illustrate the application of the results.
Influence of radio-frequency power on the state of H2/C4H8 glowing discharge plasma
Authors: Li Rui  , He Zhi-Bing  , He Xiao-Shan  , Niu Zhong-Cai  , Yang Xiang-Dong  ,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;,   Centre of Laser Fusion Research, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Taking advantage of the glowing discharge technology and plasma mass spectrometry diagnosis technology, the variation rules of positive ion species and energy with power in H2/C4H8 mixture gas are investigated. The characteristic ions are measured and their forming process is discussed. The results show that the intensity of the C-H segment ions in the H2/C4H8 plasma increases with radio-frequency (RF) power increasing, the intensity reaches a maximum at an RF power of 20 W, and then reduces after the RF power has reached 25 W. The relative concentration of m/e 57 (C4H9+) is highest when the power is less than 10 W, and when the power is more than 10 W, the relative concentration of m/e 39 (C3H3+) reaches a maximum. The energy of the C-H segment ions increases gradually with the increase of RF power. The qualitative analyses of H2/C4H8 plasma composition and energy will be beneficial to improving the fabrication technology of glowing discharge polymer coating.
Study of pulsed field emission characteristics and simulation models of carbon nanotube cold cathodes
Authors: Yuan Xue-Song  , Zhang Yu  , Sun Li-Min  , Li Xiao-Yun  , Deng Shao-Zhi  , Xu Ning-Sheng  , Yan Yang  ,   School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China;,   State Key Laboratory Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou 510275, China
Published: December 2020

For the application requirement of a carbon nanotube clod cathode (CNCC) used in the microwave and millimeter wave electric vacuum radiation source devices, pulsed field emission characteristics of CNCC are experimentally investigated by a 2 μs/20 kV high-voltage modulator in this paper. The pulsed field emission currents for different distances between anode and cathode and those of CNCC after the pulsed high-tension arc has occurred many times are studied. A maximal emission current of 16 mA is tested for CNCC with a 4 mm diameter emission disk, and the emission current density is achieved to be 127 mA/cm2. Based on the experimental results, the field emission simulation model of CNCC is established by PIC simulation software. Simulation results show that this simulation model is suited for describing the experimental results and laying the foundation for the development of CNCC electron optical system and radiation source devices.
Investigation of the temperature sensitivity of the long-wavelength InP-based laser
Authors: Yang Xin-Rong  , Xu Bo  , Zhao Guo-Qing  , Shen Xiao-Zhi  , Shi Shu-Hui  , Li Jie  , Wang Zhan-Guo  ,   Department of Physics and Electronic Engineering, Handan College, Handan 056005, China;,   Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
Published: December 2020

The long-wavelength laser on InP (001) is fabricated, the temperature dependence of threshold current density is investigated. The nomalous decrescence of threshold current density is observed with the increase of temperature, which leads to a negative characteristic temperature. The origin of this phenomenon is discussed. We attribute the anomalous temperature dependence of threshold current density to the carrier redistribution effect.
Electronic structure and optical properties of (α, β, γ)-Nb5Si3
Authors: Duan Yong-Hua  , Sun Yong  ,   Faculty of Material Science and Technology, Kunming University of Science and Technology, Kunming 650093, China;,   Key Laboratory of Advanced Materials of Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China
Published: December 2020

Based on the first-principles density functional theory, the electronic structures, densities of states and optical properties of the structures α-Nb5Si3, β-Nb5Si33 and γ-Nb5Si are calculated by using the local density approximation and plane wave pseudopotential method. The calculation results show that the valence band of Nb5Si3 near the Fermi energy is composed of Nb 4d, Si 3s, 3p orbits and the conduction band is comprised mainly of Nb 4d orbit; the optical properties of Nb5Si3 possess anisotropic characteristics, the static dielectric function ε1(0) of Nb5Si3 is about 207, and the refractive index n0 is 13. Their absorptions in a range above 15 eV approach to zero, showing the optical transparent behaviors.
Dependence of the DC stress negative bias temperature instability effect on basic device parameters in pMOSFET
Authors: Cao Jian-Min  , He Wei  , Huang Si-Wen  , Zhang Xu-Lin  ,   College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China.
Published: December 2020

To analyze the dependence of the DC stress negative bias temperature instability (NBTI) effect on basic device paraments, such as the channel length, the gate oxide thickness, the doping concentration, we solve the hydrogen molecule drift-diffusion model of NBTI together with the semiconductor device equations. The results are compared with the existing experimental data and the basic laws and physics of devices, which is necessary for reliability studies of NBTI. The analysis results show that NBTI effect is not affected by the channel length change, but maily by the thickness of the gate oxide layer. Gate oxide thickness thinning and gate oxide layer electric field enhancement effect are consistent, which determines the device degradation in the manner of exponential law. With channel doping concentration increasing, NBTI effect will be reduced, which is because the device channel surface hole concentration is reduced, however with the doping concentration increases to such a value that the device source drain leakage current is very low (low leakage device), the MBTI effect is obviously enhanced. These are helpful for understanding NBTI and designing the high performance device.
Progress of memristor modulated by interfacial effect
Authors: Jia Lin-Nan  , Huang An-Ping  , Zheng Xiao-Hu  , Xiao Zhi-Song  , Wang Mei  ,   Department of Physics, Beihang University, Beijing 100191, China
Published: December 2020

Because of its excellent non-volatile storage characteristics, simple structure, fast storage, low energy consumption and high integration, memristor has aroused a widespread interest in the field of new electronic devices. In this paper, metal-insulator-metal stack of memristor is introduced and relative memristive material, its mechanism as well as the application in the field of electronic circuits and artificial intelligence are summarized. The significant role of interfacial effects on memristive behavior and improvement of its performance is emphasized on. Especially, the effects of interface nanodots on the optimization of memristor properties are proposed. The research prospects of memristor are also analyzed and discussed.
Identification of quasars based by the variability structure function method
Authors: Tang Jie  , Fu Ming-Xing  , Wu Xue-Bing  ,   School of Physics and Telecommunication Engineering, Shaanxi University of Technology, Hanzhong 723001, China;,   Department of Astronomy, Peking University, Beijing 100871, China
Published: December 2020

The variability sky survey is a very effective method of searching for quasars. In the paper, we present a novel method to discriminate quasars from variable stars based on their intrinsic variabilities. The power-law model is used to fit the light-curve structure function in five wavebands, but the value of the structure function is normalized. The developed method is applied to 1411 spectroscopically confirmed quasars and 174 stars in SDSS stripe 82. We set a suitable criterion, then obtain a reasonable classified result. The classification accuracies about quasars and stars reach 92.2% and 83.6% respectively. Compared with the structure function only based on one physical parameter, the normalized structure function with amplitude and power-law index has a good efficiency to deal with these data. The method for selecting quasar candidates ensures big sky survey telescope a high survey efficiency and saving valuable astronomical observation time. The results support that the optical variabilities of most of quasars originate from the instabilities of accretion disks.
On the recharge-discharge oscillator model for El Niño-Southern Oscillation (ENSO)
Authors: Zhao Qiang  , Liu Shi-Kuo  , Liu Shi-Da  ,   School of Physics, Peking University, Beijing 100871, China
Published: December 2020

A kind of recharge-discharge oscillator model for the El Niño-Southern Oscillation (ENSO) is considered. By transforming the ENSO model into the van der Pol equation and analyzing its properties qualitatively, we proved that the ENSO recharge-discharge oscillator model possesses a stable limit cycle.
Analysis of lasing in gain medium based on four-energy level atomic model
Authors: Sun Bing-Bing  , Wu Bo  , Wang Hui  , Huang Zhi-Xiang  , Wu Xian-Liang  ,   Key Laboratory of Intelligent Computing and Signal Processing, Anhui University, Hefei 230039, China;,   Department of Physics and Electronic Engineering Hefei Normal University, Hefei 230061, China
Published: December 2020

With the present interest in metamaterial, gain medium shows promise for complex system due to their amplification effect and wide potential application area. In this paper we present a model that simulates lasing in gain medium by using a model of four-energy level atomic system based on the finite-difference time-domain method.Meanwhile we propose a new pump mechanism, i.e., Gaussian Pump. It is found that results of the spectra, lasing threshold and population dynamics of the new pump mechanism are in good agreement with theoretical results. The results can also provide reference for caculating more complex metamaterial system.
Two-dimensional quantum spectra and classical orbits of isosceles- right triangular billiards
Authors: Liu Xiang-Long  , Zhu Man-Zuo  , Lu Lu  ,   School of Electronic Engineering Xi’dian University, Xi’an 710071, China
Published: December 2020

The quantum spectra are derived from the wave-functions and the energy-functions of the isosceles-right triangular model. Although the eigenstates of the billiard system are not separable, the problem of functions with two variables is exactly solvable. The numerical results of the Fourier transform of quantum spectral functions are compared with the results from the classical orbits whose lengths match well with the positions of the spectra peaks. This result gives a new evident for the correspondence of quantum and classical mechanics.
Synchronization of fractional order hyperchaotic Chen system based on PIα control
Authors: Chen Zhi-Wang  , Wang Jing  , Pang Shuang-Jie  ,   Key Lab of Industrial Computer Control Engineering of Hebei Province, Yanshan University, Qinhuangdao 066004, China;,   National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Qinhuangdao 066004, China;,   Qinhuangdao Institute of Technology, Qinhuangdao 066100, China
Published: December 2020

In this paper, a kind of PIα controller is designed for the synchronization of fractional order hyperchaotic Chen system. The controller is designed according to the fractional order hyperchaotic Chen system. The stability of the system is proved by the improved double parameter Mittag-Leffler function estimate theorem and the extended Gronwall lemma. Furthermore, the condition of controller parameters is pointed out which makes the fractional order hyperchaotic Chen system synchronous. Numerical simulations are presented to verify the effectiveness of the method.
Chaos synchronization between complex networks with uncertain structures and unknown parameters
Authors: Zhang Meng  , Lü Ling  , Lü Na  , Fan Xin  ,   College of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China
Published: December 2020

Chaos synchronization between complex networks with uncertain structures and unknown parameters is investigated. By designing appropriate control inputs, we achieve the synchronization between two complex networks. The unknown parameters of nodes at two networks and the coupling strength between the nodes are identified simultaneously in the process of synchronization. The CO2 laser equation with modulation loss is taken for example to simulate experiment. It is found that the synchronization performance between two networks is very stable.
Extended Holme-Kim network model and synchronizability
Authors: Wang Dan  , Jing Yuan-Wei  , Hao Bin-Bin  ,   Key Laboratory of Manufacturing Industrial Integrated Automation, Shenyang University, Shenyang 110044, China;,   College of Information Science and Engineering, Northeastern University, Shenyang 110004, China
Published: December 2020

The relations between two highly clustered scale-free network evolution mechanisms and synchronizability are studied in this paper. Firstly, we propose an extended Holme and Kim (EHK) model with adjustive clustering coefficients and power-law exponent based on the Holme and Kim (HK) model. Triad formation mechanism is extended among old nodes compared with the HK model. And the following shortages of HK modle are settled: there is no link evolution in old nodes and the numbers of links of a new node adding to network is fixed. Secondly, the effect of triad formation on synchronizability in an unweighted network is investigated. Finally, simulation results show that the triad formation mechanism can weaken the synchronizability of both types of networks.
The total dose irradiation effects of SOI NMOS devices under different bias conditions
Authors: Zhuo Qing-Qing  , Liu Hong-Xia  , Yang Zhao-Nian  , Cai Hui-Min  , Hao Yue  ,   Key Laboratory for Wide Band Gap Semiconductor Materials and Devices of Education, School of Microelectronics, Xidian University, Xi’an 710071, China
Published: December 2020

Based on 0.8 μm process, in the paper we investigate the total dose irradiation effects of SOI NMOS devices under different bias conditions. The devices are exposed to 60Co γ ray at a dose rate of 50 rad (Si)/s. In higher gate bias condition, the drain leakage current increases because more positive charges are trapped in the buried oxide. When the applied gate voltage is larger than the threshold voltage, its drain current of the front gate in ID-VG characteristic suddenly increases and the body current presents a unique upside down bell shape.
Generation of the three-dimensional array of optical trap by spatial light modulator
Authors: Xu Shu-Wu  , Zhou Qiao-Qiao  , Gu Song-Bo  , Ji Xian-Ming  , Yin Jian-Ping  ,   Science College, Nantong University, Nantong 226007, China;,   State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China
Published: December 2020

In this paper, a new scheme of generating a three-dimensional array of optical trap is proposed by using a composite phase grating that is fabricated by liquid crystal spatial light modulator. The composite phase grating is formed by combining the circular grating, which is generated by transforming a one-dimensional rectangular grating into a circular grating that can produce the longitudinal array of optical trap, with a two-dimensional rectangular grating. The grating that generates 5× 5× 5 array of optical trap is simulated according to the technical parameters of the spatial light modulator. The output intensity distribution is calculated by using the Gaussian light wave with ordinary power as input light and focusing the diffracting light with lens. The results show that three-dimensional array of optical trap with a very high peak value of intensity and an intensity gradient is obtained around the focus of the lens. The optical dipole potential of trapping cold atoms achieves the order of mK, and the interaction force between the atom and the optical field is much greater than the atom gravity. When the high power laser is used as input light, the generated array of optical trap can also be employed to trap the cold molecules produced by Stark deceleration.
Bidirectional chaos communication based on two semiconductor lasers subjected to incoherent optical injection of common-chaotic-signal
Authors: Wei Yue  , Fan Li  , Xia Guang-Qiong  , Chen Yu-Lin  , Wu Zheng-Mao  ,   School of Physical Science and Technology, Southwest University, Chongqing 400715, China
Published: December 2020

Based on the chaotic synchronization between two response semiconductor lasers (RLs) subjected to incoherent optical injection of common-chaotic-signal from a driven laser (DL), a bidirectional chaos communication scheme is proposed, and the chaotic synchronization characteristics and the effects of intrinsic mismatched parameter on the synchronization performances are numerically investigated. The results show that high-quality chaos synchronization between the two RLs can be achieved while the cross-correlation coefficients between the two RLs and the DL are very low under proper operation condition; the intrinsic parameter mismatching between two RLs will destroy the synchronized quality to a certain extent, but the consequence is not severe. Additionally, the bidirectional transmission performances for two messages with 2Gbit/s and the security of the scheme are also analyzed.
Insitu neutron diffraction study of micromechanical interaction and phase transformation in dual phase NiTi alloy during tensile loading
Authors: Sun Guang-Ai  , Wang Hong  , Wang Xiao-Lin  , Chen Bo  , Chang Li-Li  , Liu Yao-Guang  , Sheng Liu-Si  , Woo Wanchuck  , Kang Mi-Hyun  ,   Key Laboratory for Neutron Physics of Chinese Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang 621900, China;,   Department of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China;,    School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China;,   Neutron Science Division Korea Atomic Energy Research Institute, Daejon 305-353, South Korea
Published: December 2020

It is well known that the shape memory effect of NiTi alloy is closely related to the micro-structural characteristics. Neutron diffraction method can used to explore the changes of the phase transformation, lattice strain and twining reorientation of bulk NiTi alloy during deformation caused by the applied stress. In this paper, combining the four types of deformation characteristics in the macro stress-strain curves of dual phase NiTi alloy and using in-situ neutron diffraction measurement, the micromechanical interactions and phase transformation are determined. The volume fraction of the initial austenite before deformation is about 22%. The contrast transformation, which is corresponding to the lattice strain rapid decreasing of (110)B2 and increasing of (002)B19', reveals that the stress-induced transformation from austenite to martensite phase appears with the volume fraction of austenite decreasing rapidly and 011 II type twinning increases at the low strain hardening stage. At the same time, the initial martensite grains change their orientation to a favorable direction and the new {201} type martensite twinnings induced with the increase of applied stress cannot recover after unloading. At the high strain hardening stage, the twinning deformation is considered to be the main mechanism from the observing of the changes in the full width at half maximum (FWHM). Meanwhile, the slipping caused by dislocation is the main deformation mechanism corresponding to the obvious increas of the FWHM at the statured stage of the strain hardening.
Mechanical parameters selection in InSb focal plane array detector normal direction
Authors: Meng Qing-Duan  , Yu Qian  , Zhang Li-Wen  , Lü Yan-Qiu  ,   School of Electronic Information Engineering, Henan University of Science and Technology, Luoyang 471003, China;,   China Airborne Missile Academy, Luoyang 471009, China
Published: December 2020

In order to learn the effects of front surface structural defects and back surface thinning process on the InSb chip deformation, its elastic modulus along normal direction is reduced in InSb structural modeling, and based on the typical strain character appearing under thermal shock, the mechanical parameter selection basis is deduced in this paper. Simulation results show that when the out-of-plane elastic modulus of InSb chip is set to be 30 percent Young's modulus, both the maximum Von Mises stress and Z component of strain appear in the N electrode zone, and the extremum values present non-continuous distribution. These are in good agreement with fracture origination zone and crack distribution in the fracture statistics results of 128 128 InSb infrared focal plane array under thermal shock. Besides, the region above the indium bump array is convex upward, and the domain above the isolation trough is concave downward, they are also identical with the scenario of Z component of strain in InSb chip under thermal shock. All these results indicate that the Z component of strain criterion can not only predict both crack origination zone and crack distribution, but also support both Z component of strain distribution in the central region and Z component of strain enhancement effect in the InSb chip N electrode zone.
Mechanical resonance based acoustic spectrographic technique
Authors: Song Wei  , Chen Yu-Hao  , Li Xiao-Hui  , Zhang Xian-Liang  , Wang Jia-Hui  , Cai Zhi-Gang  ,   School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, China;,   State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-sen University, Guangzhou 510275, China
Published: December 2020

A model for the accurate measurement of low frequency sound spectrum is put forward and a simplified experimental device is built. Based on the principle of mechanical resonance, the natural frequency of the system is controlled, which realizes the function of both measuring frequency spectrum and monitoring noises at low frequency. The device is able to measure the acoustic source at a single frequency below 100 Hz as well as to analyze the spectra of acoustic sources at mixed frequencies, with a relatively high resolution of 1 Hz beyond 40 Hz.
Study of the evolution of helium bubbles in helium-containing titanium films
Authors: Wang Kang  , Deng Ai-Hong  , Liu Li  , Li Yue  , Zhou Yu-Lu  , Hou Qing  , Zhou Bing  , Wang Shan-Lin  ,   Department of Physics, Sichuan University, Chengdu 610064, China;,   Key Laboratory for Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China;,   College of Computer Science and Technology, Southwest University for Nationalities, Chengdu 610041, China;,   Analytical & Testing Center, Sichuan University, Chengdu 610064, China
Published: December 2020

In this paper, the evolution of the He-related defects in the titanium film is experimentally investigated by combining slow positron beam analysis (SPBA) and transmission electron microscope (TEM) technique. The results indicate that small bubbles in the titanium film distribute uniformly at room temperature. With the increment of He concentration, the density of He bubbles in the sample increases correspondingly. Large bubbles are observed in the titanium film containing high He concentration after 973 K high temperature annealing, and it is found that both migration-coalescence and cascade-coalescence around the bigger He bubbles lead to the rapid growth of He bubbles.
Preparation, structures and electrical properties of alkaline earth and transition metal-doped NdAlO3 conducting ceramics
Authors: Xiang Jun  , Guo Yin-Tao  , Zhou Guang-Zhen  , Chu Yan-Qiu  ,   School of Mathematics and Physics, Jiangsu University of Science and Technology, Zhenjiang 212003, China
Published: December 2020

Novel Nd0.9Sr0.1Al1-xMxO3-δ (M = Co, Fe, Mn; x =0, 0.15, 0.3, 0.5) conducting ceramics each with a hexagonal perovskite structure are prepared using organic-gel method combined with subsequent high temperature sintering. The influences of transition elements (Co, Fe, and Mn) and their dosages on the structure characteristics and electrical properties are investigated in detail. The experimental results reveal that well-crystallized Nd0.9Sr0.1Al1-xMxO3-δ perovskite oxide ultrafine powders can be obtained by calcining the gel precursors at 900 ℃ for 5 h. The lattice parameters of sintered ceramics increase with the increase of transition metal content (x), and they increase according to the order of Co, Mn, and Fe. All the samples are mixed conductors of oxygen ions and holes in air, and the oxygen ion transport number is enhanced monotonically from 0.32 at 500 ℃ to 0.63 at 850 ℃ for NdAlO3-δ ceramic single-doped with alkaline earth metal Sr, indicating that this material has an electronic-to-ionic dominant transition in electrical conductivity with measurement temperature increasing. Whereas the oxygen ion transport numbers are all below 0.001 for the samples co-doped with Sr and transition metals (Co, Fe, and Mn), and their electrical conductivities are absolutely dominated by p-type conduction. It is found that the conductivity values increase with the increase of x value, and they increase according to the order of Mn, Fe, and Co, while the change of corresponding apparent activation energies is just the opposite. Nd0.9Sr0.1Al0.5Co0.5O3-δ ceramic has the highest electrical conductivity, ～100.8 S/cm at 800 ℃, and the lowest apparent activation energy (0.135 eV) in all the synthesized samples. The observed changes in structure and electrical property in this study can be explained on the basis of the difference in ionic radii among the doped transition metals as well as the differences in bond energies and covalencies among the M-O bonds.
Breakdown voltage analysis for new Al0.25Ga0.75N/GaN HEMT with F ion implantation
Authors: Duan Bao-Xing  , Yang Yin-Tang  , Kevin J. Chen  ,   Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, XidianUniversity, Xi’an 710071, China;,   Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
Published: December 2020

In order to alleviate the leakage current of AlGaN/GaN High Electron Mobility Transistors (HEMT) device with the N-type GaN buffer, the new Al0.25Ga0.75N/GaN HEMT with the Fluoride ion implantation is proposed for the first time in this paper. Firstly, the output characteristic has the ohmic characteristic for the AlGaN/GaN HEMT without acceptor-type trap, which explains why Fe and Mg are doped into the GaN buffer layer as reported in the literature in theory and simulation. By using the output characteristics of the Ids-Vds for the AlGaN/GaN HEMTs with and without low density drain, the results are obtained that fluoride ion implantation can capture effectively the electrons emitted from the source to reduce the leakage current of the GaN buffer compared with fluoride ions in the gate and the drain regions. The breakdown voltage goes up to 262 V. The scientific basis is set up for desiging the new AlGaN/GaN HEMT with both the low leakage current and the high breakdown voltage.
Density functional theory study on transparent conductive oxide CuScO2
Authors: Fang Zhi-Jie  , Mo Man  , Zhu Ji-Zhen  , Yang Hao  ,   Department of Information and Computation of Science, Guangxi University of Technology, Liuzhou 545006, China;,   State Key Laboratory for Superlattics and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
Published: December 2020

Using the first-principle method within the generalized gradient approximation, in this paper we study the band structure, state density and doping level of transparent conductive oxide CuScO2. The calculated results show that the valence band of CuScO2 is composed mainly of 3d of Cu, and 2p of O; while the conduct band is comprised mainly of 3d of Sc. Through the +U correction, with the increase of the value of U, the conduct band of CuScO2 becomes split, and results in the enlarged band gap, which shows that the +U correction can improve the band gap of CuScO2. By comparing all kinds of dopant level in CuScO2, it found that the substitution of Mg for Sc can effectively improve the p-type conductivity in CuScO2.
Ag antidot array modified TiO2 film and its photocatalysis performance
Authors: Qi Hong-Fei  , Liu Da-Bo  , Cheng Bo  , Hao Wei-Chang  , Wang Tian-Min  ,   Department of Structural Steel, Functional Material and Metal Heat Treatment Technology, Beijing Institute of Aeronautical Materials, Beijing 100095, China;,   Center of Condensed Matter and Material Physics, Beihang University, Beijing 100191, China
Published: December 2020

Ag antidot arrays modified TiO2 films are obtained by PS colloidal crystal template technique and magnetron sputtering method, and the microstructure of Ag antidot array is modulated through controlling the sputtering power. And then, the structural and the photocatalysis performances of all samples are characterized by using scanning electron microscopy, X-ray diffraction, UV-Vis spectrophotometer, and four-point probe. The experimental results show that the microstructure of Ag antidot array significantly influences the photocatalysis performance of the sample. With the diameter of the antidot array decreasing, the photocatalysis performance of the sample is enhanced due to the increase of conducting ability. The photocatalysis performance is highest, when the diameter of the antidot array is 710 nm. Subsequently, with the diameter of the antidot array further decreasing, the photocatalysis performance decreases to a certain extent, which results from the increases of the carrier loss and the light shading area. The photocatalysis performance of Ag antidot array modified TiO2 film is superior to that of TiO2 film. This is attributed to the fact that the Ag antidot array could effectively promote the separation of surface photoinduced charge carrier of TiO2 nanoparticles, which is responsible for the remarkable increase in photocatalytic activity.
Structural analysis of Cu(In1-xGax)Se2 multi-layer thin film solar cells
Authors: Pan Hui-Ping  , Bo Lian-Kun  , Huang Tai-Wu  , Zhang Yi  , Yu Tao  , Yao Shu-De  ,   State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China;,   Department of Physics and Electionic Science, Qiannan Normal College for Nationalities, Duyun 558000, China;,   Institute of Photoelectronic Thin Film Device and Technology, Nankai University, Tianjin 300071, China
Published: December 2020

In this paper, the complex structure of CuInGaSe (CIGS), which is fabricated by a two-step progress (the deposition step and the salinization) or co-evaporation method, is analyzed in detail by several methods. Rutherford backscattering spectroscopy (RBS) shows unique advantage for investigating CIGS multi-layer. For the two-step CIGS thin films, both Ga and In atoms reveal a gradient distribution. Such a distribution that Ga atoms are more likely to be localized in a deeper layer of surface than in a shallow layer of surface, has no relation with the Mo layer. RBS and Auger electron spectroscopy (AES) prove that there appears diffusion in the interfaces of multi-layers, especially the interfaces of CdS and CIGS, Mo and CIGS. X-ray fluorescence (XRF) indicates that CIGS thin film presents the highest efficiency when the content ratio of In and Ga atoms is 0.7:0.3. Structural investigation by X-ray diffraction reveals the improved crystalline quality after annealing.
A novel local-world-like evolving bipartite network model
Authors: Tian Li-Xin  , He Ying-Huan  , Huang Yi  ,   Faculty of Science, Jiangsu University, Zhenjiang 212013, China
Published: December 2020

In complex networks, node degree values are limited by some practical factors. The saturation of node degree, which is a function of network evolution time, is defined first. We propose a novel evolving bipartite network model based on preferential attachment in local-world, which is generated by node saturation restrictions, not new node selection. So we also call it local-world-like model. However, the numerical simulation results display that the degree distribution does not obey the power-law distribution. We find that the degree value interval of this local-world-like bipartite network is small. There is no hub node. In addition to these, we analyze mixing coefficient of the network and find that the assortativities of the network are different when the network is generated by different initial parameters Such a result accords with our simulated result.
Phase diversity image restoration
Authors: Li Fei  ,   The Northern Institute of Electronic Equipment, Beijing 100083, China
Published: December 2020

The image quality of the imaging system is often reduced by the wave-front aberrations which arises from a variety of sources including atmospheric turbulence, system aberration, and so on. Phase diversity image restoration is an image restoration technique that mainly aims to solve the problem of wave-front aberrations. This technique needs neither reference object nor the degraded function and has a good convergence. It can enhance the resolution and sharpness, increase the information content and improve the visual effect of the image, and has broad application prospect in the field of image restoration. In this paper, the phase diversity image restoration technique is studied, and its performance is analyzed in virtue of the concept of the optical transfer function, modulation transfer function and point spread function. Simulation and experimental results both show that phase diversity image restoration technique can not only reduce the influence of wavefront aberrations but also increase the information of low frequency within the cutoff frequency, and improve the contrast. So, the image acquired by phase diversity image restoration can be better than the image acquired by the diffraction limited system.
Manipulation of entanglement and preparation of quantum states for moving two-atom and the light field via intensity-dependent coupling
Authors: Liu Xiao-Juan  , Zhou Bing-Ju  , Liu Yi-Man  , Jiang Chun-Lei  ,   School of Physics, Hunan University of Science and Technology, Xiangtan 411201, China
Published: December 2020

In this paper, the Tavis-Cummings model is generalized to simultaneously consider the atomic motion and the field via intensity dependent coupling. Under the conditions of vacuum field, weakly and strongly coherent field, the entanglement evolution properties of two-atom-field and two-atom-two-atom are investigated using atomic reduced entropy and concurrence, respectively. According to evolution characteristics above, we prepare the W-class states of two-atom-field, two-atom Bell state, fidelity state of Bell-state atoms, single-photon state, two-photon state and stable number-states of field by selecting the interaction time of the two-atom-field, selecting the entanglement factor of the two-atom, regulating the field-mode structure parameter, controlling the probability amplitude of pure state of the system and selective measurement. The manipulation of two-atom Bell state sudden generation and its maintenance in a limited time, the formation of periodic quantum echo of Bell-state atoms and the continuous fidelity of Bell-state atomic information are achieved. The results show that the system has a powerful function of quantum information, and provide the physical carrier and theoretical parameters for experimental implementation of quantum information processing.
Large parameter stochastic resonance of two-dimensional Duffing oscillator and its application on weak signal detection
Authors: Leng Yong-Gang  , Lai Zhi-Hui  , Fan Sheng-Bo  , Gao Yu-Ji  ,   School of Mechanical Engineering, Tianjin University, Tianjin 300072, China;,   Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300072, China
Published: December 2020

In this paper, the stochastic resonance of two-dimensional Duffing oscillator under the adiabatic assumption is studied. For the large parameter condition, we propose the large parameter stochastic resonance of two-dimensional Duffing oscillator, and discuss the relationship between the scale transformation stochastic resonance and the parameter adjustment stochastic resonance. Then we reveal the mechanism of signal detection by Duffing oscillator stochastic resonance in large parameter condition, and extend its application to weak signal detection.
Mass analysis of the isoscalar state of the 23P2 meson nonet
Authors: Feng Xue-Chao  , Chang Tong-Qin  ,   Department of Technology and Physics, Zhengzhou University of Light Industry, Zhengzhou 450002, China
Published: December 2020

In the view of the experimentally confirmed existence of the a2(1325), f2(1525), f2(1270) and K2*(1430), which are the ground tensor meson 13P2 members, through combining the Regge trajectory and meson mass mixing matrix, we investigate the assignment of the first radial excitation of tensor meson. We suggest that the states f2(1810) and f2(2010) should be the candidates of this assignment. Moreover, some information about decaying of f2(1810) and f2(2010), which serve as pseudoscalar mesons, are presented. The results should be tested in the experiment in the future.
Electron-vibration approximate method for hydrogen isotope compounds Al2O3X2 (X= H, D, T)
Authors: Yang Lei  , Shen Xiao-Hong  , Wang Ling  , Hu Lian-Rui  ,   School of Physics-Chemistry, Xihua University, Chengdu 610039, China;,   Research Center for Advanced Computation, Xihua University, Chengdu 610039, China
Published: December 2020

The geometric configurations, vibration frequencies and thermodynamics properties of Al2O3X2 (X= H, D, T) molecular clusters with lower energy are optimized using the B3LYP/6-311++g (d, p) method. The changes of entropy, enthalpy and Gibbs free energy of the reactions between Al2O3 and hydrogen (deuterium or tritium) gas are calculated by the solid electron-vibration approximate method and thermodynamic formulae at temperatures of 298, 398, 498, 598, 698, 798, 898, 998 and 1098 K, and then the relationships between the equilibrium pressure of hydrogen (deuterium or tritium) gas and temperature in these reactions are obtained. The results show that the ground state of the gaseous Al2O3H2 is Al2O3X2 (X= H, D, T) (1A') Cs. Hydrogen can be displaced by deuterium; deuterium can be displaced by tritium in the reactions between Al2O3 and X2 with the productions of solid Al2O3X2 which relates to ground gaseous Al2O3X2 with Cs symmetry. This displacement sequence is opposite to that in the reactions between titanium and X2. These displacement effects are very weak, and they are weaker and weaker as the temperature increases.
Isolated attosecond pulse generated by a model helium atom exposed to the combined field
Authors: Huang Feng  , Li Peng-Cheng  , Zhou Xiao-Xin  ,   Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Published: December 2020

We theoretically study the high-order harmonic generation (HHG) of a model He atom exposed to a combined field of 1600 nm and 800 nm laser pulses. The changing of rising rate and falling rate with time for the combined filed during main HHG, can present the different characteristics of high-order harmonic generation from the short electron trajectories and the long electron trajectories. By superimposing several harmonics generated from He atom driven by the combined field, we could obtain shorter attosecond pulses. Finally, by adjusting the time delay between two laser pulses, we can effectively suppress the contribution of the short electron trajectories to HHG, and obtain an isolated attosecond pulse with duration 33.7 as.
Simulation study of radiography using laser-produced electron beam
Authors: Xiao Yuan  , Wang Xiao-Fang  , Teng Jian  , Chen Xiao-Hu  , Chen Yuan  , Hong Wei  ,   Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China;,   Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Laser accelerated high-energy electron beam has the properties of small source size, quasi-monoenergetic, and short duration. In this paper the radiography by the electron beam is simulated using a Monte-Carlo code. Various radiographies are simulated, such as a step target and a thick iron block of inside cracks by a collimated 200-MeV beam, a modelled inertial-confinement-fusion target by a 11-MeV point-like beam, and the deflectometry of a 70-MeV electron beam by a laser plasma generated magnetic field. The obtained results indicate that the radiography by a laser-accelerated electron beam is of high spatial resolution and sensitivity in the detection of the inside defects of material, identification of the interface of thin material, and diagnosis of electromagnetic field.
The effect of polarization light on optical imaging system
Authors: Pang Wu-Bin  , Cen Zhao-Feng  , Li Xiao-Tong  , Qian Wei  , Shang Hong-Bo  , Xu Wei-Cai  ,   State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China;,   State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
Published: December 2020

Normally, Strehl ratio, resolution, and focus depth, the parameters that are used to evaluate the performance of an optical imaging system, are always calculated by scalar diffraction method. Considering the vectorial properties of light, especially when the system numerical aperture (NA) is high, the accuracy of scalar method can no longer fulfill the requirement of analysis. The variations of properties of these parameters accompanied by using of vectorial method are discussed. In order to describe the effects of polarization clearly, assuming a system with identical polarization state within the entrance pupil, by formula deduction and numerical simulation, we conclude that due to the influence of the polarization, the maximum intensity of system diffraction spot decreases, the resolution between image plane and parallel polarized orientation of incident light drops down, then the diffraction spot loses its circular symmetry, the focus depth changes slightly, and these effects becomes more apparent with the increase of system NA. Finally, the method of calculating the off-axis images is discussed in the paper.
Composition and temperature dependence of the light-induced scattering in Fe-doped lithium niobate
Authors: Shi Li-Hong  , Yan Wen-Bo  , Shen Xu-Nan  , Chen Gui-Feng  , Chen Hong-Jian  , Qiao Hui-Bin  , Jia Fang-Fang  , Lin Ai-Diao  ,   Department of Physics, Tianjin Urban Construction Institute, Tianjin 300384, China;,   School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China
Published: December 2020

In this paper, Fe-doped lithium niobate crystals with different Li compositions are prepared. The composition and temperature dependence of the light-induced scattering in Fe-doped lithium niobate are studied. The results show that the crystals with the compositions lower than 49.0 mol% suffer from the serious light-induced scattering, but when the composition increases to 49.3 mol% the light-induced scattering is suppressed significantly, in particular at a composition of 49.8 mol% the light-induced scattering disappears completely. It is also found that the light-induced scattering of the crystals with lower compositions can be suppressed completely by elevating the temperature to 150 ℃. However the temperature for the complete suppression of the light-induced scattering in the crystal with a composition of 49.3 mol% is only 80 ℃. Based on these results, it is suggested that a critical Li composition may exist in a range from 48.9 mol% to 49.3 mol% and beyond this composition the suppression and temperature dependence of the light-induced scattering will change significantly.
Effect of point defects on copper precipitation in heavily boron-doped Czochralski silicon p/p+ epitaxial wafer
Authors: Ji Chuan  , Xu Jin  ,   College of Materials, Xiamen University, Xiamen 361005, China;,   Fujian Provincial Key Laboratory of Fire Retardant Materials, Xiamen 361005, China
Published: December 2020

The effect of point defects on copper precipitation in heavily boron-doped Czochralski silicon epitaxial wafer is systematically investigated by optical microscopy. The samples first experience the rapid thermal processing (RTP) in different atmospheres, and then are Cu-contaminated at different temperatures. It is found that RTP in O2 ambient leads to a low density of copper precipitation in the p+ substrate, however, high density of copper precipitation is observed in the sample subjected to RTP in Ar or N2 ambient. Additionally, in all of the samples, no defects are found in the epitaxial layer. On the basis of the experiments, it can be concluded that interstitial silicon will prevent the process of copper precipitation while vacancy has an opposite effect. Furthermore, p/p+ epitaxial structure could absorb copper impurities, thereby keeping the epitaxial layer free of defect.
Study on metal ejection under laser shock loading
Authors: Xin Jian-Ting  , Gu Yu-Qiu  , Li Ping  , Luo Xuan  , Jiang Bai-Bin  , Tan Fang  , Han Dan  , Wu Yin-Zhong  , Zhao Zong-Qing  , Shu Jing-Qin  , Zhang Bao-Han  ,   Research Center of Laser Fusion, CAEP, P.O.Box 919-986, Mianyang 621900, China
Published: December 2020

Dynamic response of metal to shock loading plays an improtant role in the fields of civil engineering, aeronautics, etc. The forming process of ejection of metal under shock loading, including micro-jet, fragmentation and micro-spall remain to be studied. The present work is devoted to laser-shock experiments in metal ejection on the SGIII laser facility. And the fragment recovery and post-test evaluation of the fragment-size distribution are achieved.