bluuebunny/crossref_metadata_2025 huggingface dataset:
On weightd scale-free network model with tunable clustering and congesstion
Authors: Wang Dan  , Jin Xiao-Zheng  ,   Key Laboratory of Manufacturing Industrial Integrated Automation, Shenyang University, Shenyang 110044, China
Published: December 2020

We propose an evolutionary model for weighted network with tunable clustering coefficient according to characteristics of real network. The model gives power-law distributions of degree, weight, and strength, as confirmed in many real network. In particular, the weighted model has a nonlinear correlation between average clustering coefficient and degree, which is in good agreement with flat head real weighted technological network. Moreove, the effect of the weighted network structure on traffic delivery is studied. The packet traffic flow on the weighted scale-free network is investigated based on the local routing strategy using node strength, and the delivering ability of node is controlled by node strength. The simulations show that the traffic dynamics depends strongly on the controlled parameter.
Comparison of entanglement decay between Bell-like states under different environmental models
Authors: Han Wei  , Cui Wen-Kai  , Zhang Ying-Jie  , Xia Yun-Jie  ,   Department of Physics, Qufu Normal University, Qufu 273165, China;,   Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165, China
Published: December 2020

Establishing three different environment models (i.e., single reservoir model, common reservoir model and independent reservoir model), we investigate the evolutional characteristic of the entangled system initially in Bell-like state by the pseudomode method. Through comparing the entanglement decays under the three different environment models, we find that the entangled Bell-like state cos θ |ee> + sin θ |gg> will be kept in the single reservoir model for a time longer than in the other two models. However, the entanglement decay behavior of Bell-like state cos θ |eg> + sin θ |ge> is dependent on the specific environment model. Meanwhile, the comparison of entanglement decay between the above two Bell-like states at the same environment models is performed.
Experimental confirmation on period-doubling bifurcation and chaos in dielectric barrier discharge in helium at atmospheric pressure
Authors: Wang Xiao-Qing  , Dai Dong  , Hao Yan-Peng  , Li Li-Cheng  ,   School of Electric Power, South China University of Technology, Guangzhou 510641, China;,   State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

A series of dielectric barrier discharge (DBD) experiments in helium at atmospheric pressure is carried out under a parallel electrode configuration. The discharge waveforms are observed in time-domain and analyzed in frequency-domain. Results show that under a certain condition the discharge can experience period-one, period-two and period-four discharges and finally enters into chaotic discharge as the amplitude of the driving voltage is increased. Our work verifies that the period-doubling route into chaos in DBD at atmospheric helium pressure can observed in experiment, beside in numerical simulations.
Investigation of experimental parameters of coherent population trapping with cesium vapor cell
Authors: Liu Zhi  , Diao Wen-Ting  , Wang Jie-Ying  , Liang Qiang-Bing  , Yang Bao-Dong  , He Jun  , Zhang Tian-Cai  , Wang Jun-Min  ,   State Key Laboratory of Quantum Optics and Quantum Optics Devices (Shanxi University) and Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China
Published: December 2020

According to the Λ -type three-level system consisting of cesium 6S1/2 (F=3 and F=4) long-lived ground states and 6P3/2 (F'=4) excited state, we experimentally investigate and theoretically analyze the parameters of coherent population trapping (CPT) spectra in a cesium atomic vapor cell with or without neon as buffer gas. The CPT of the full width at half maximum (FWHM), the signal amplitude as a function of optical intensity of the two phased-locked laser beams with a frequency difference of 9.19263177 GHz (the hyperfine splitting in the cesium ground state 6S1/2), relative intensity ratio, beam spot size, residual magnetic field of the magnetic shielding, and the influence of with and without the cesium vapor cell containing neon as buffer gas are investigated experimentally. With the optimized parameters, we obtain the CPT signal FWHM to be as narrow as ～ 340 Hz.
The two-dimensional phononic crystal band gaps tuned by the symmetry and orientation of the additional rods in the center of unit cell
Authors: Hu Jia-Guang  , Xu Wen  , Xiao Yi-Ming  , Zhang Ya-Ya  ,   School of Physical Science and Technology, Yunnan University, Kunming 650091, China;,   Department of Math and Physics, Wenshan University, Wenshan 663000, China
Published: December 2020

The effects of symmetry and orientation of the additional steel rods on the band gaps of two-dimensional phononic crystals with steel-air system are numerically investigated by using the plane wave expansion method. The original steel rods of the phononic crystals are of columns in square and hexagonal lattices, and the additional steel rods are of regular square, hexagon, octagon prisms and columns, which are placed, respectively, in the center of each unit cell of the two kinds of lattices. The gap maps are introduced to illustrate the influences of the filling fraction and orientation of the additional rods on band gaps. It is found that in the case of the additional rods with low filling fraction, the band gaps can be obtained most easily because the degeneracy of bands is lifted when the cross section of additional rod has the same shape as that of lattice, but the widest band gaps appear under the condition of the additional rods with highest symmetry and largest filling fraction. The influence of orientation on band gap in square lattice is more obvious than that in hexagonal lattice. If the column lattice points are changed by square prisms in simple square lattice, the lower and wider band gaps can be produced by rotating the square prisms, which is contrary to the scenario that emerges in square lattice with additional rods at the center of unit cell. Using one of the methods of adding additional rods or rotating the original prisms is more beneficial to the generation of band gaps than combining effect of these two means in simple lattices. Furthermore, the mechanisms of above results are analyzed.
Simulation of residual stress in viscoelastic mold filling process
Authors: Yang Bin-Xin  , Ouyang Jie  ,   School of Applied Science, Taiyuan University of Science and Technology, Taiyuan 030024, China;,   Department of Applied Mathematics, Northwestern Polytechnical University, Xi'an 710129, China
Published: December 2020

Flow induced residual stress is the major reason for stress cracking and warping of plastic products, the study on which is significant to overcome the flaws of products. In this paper, the energy equation based on Extended Pom-Pom constitutive relationship is deduced. A non-isothermal viscoelastic-Newtonian two-phase fluid model for mold filling process of viscoelastic materials is set up. The conservative interface capturing technique and the flow field solving method are coupled to perform a dynamic simulation. The distribution of the frozen skin layer and the shear rates are given. The flow induced residual stress is predicted and analyzed. The numerical results show that the thickness of the frozen skin layer is dependent on the injection velocity and a higher injection velocity corresponds to a thin frozen skin layer. Near the walls of the product, the shear rate and the residual stress are almost zero. At the position of subsurface, the shear rate and the residual stress reach their largest values. At the positions far away from the walls of the product, the shear rate and the residual stress are small.
Effects of pressure and incident power on self-organization pattern structure during microwave breakdown in high pressure air
Authors: Zhu Guo-Qiang  , Jean-Pierre Boeuf  , Li Jin-Xian  ,   School of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China;,   Laboratoire Plasma et Conversion d'Energie (LAPLACE), INPT, UPS, Université de Toulouse, 118 Route de Narbonne, F-31062 Toulouse Cedex 9, France
Published: December 2020

Pressure and microwave power are the most important parameters during microwave breakdown in air and affect the self-organization plasma pattern structure and its propagation directly. In order to study the effects of pressure and microwave power, an effective-diffusion fluid plasma equation is solved together with Maxwell's equations, and the double grid method is also used to meet the different grid size requirement of plasma equation and finite-difference-time-domain for Maxwell's equations. The numerical results show that with lower pressure the plasma behaves as a more diffuse plasmoid instead of a well defined plasma pattern structure under higher pressure, and the increase of incident microwave power will lead to a rapid growth of the front propagation velocity and a well separated and sharp pattern structure, and the higher incident power also results in jump-like front propagation.
First principles calculation of electronic structure for Al-doped 3C-SiC and its microwave dielectric properties
Authors: Li Zhi-Min  , Shi Jian-Zhang  , Wei Xiao-Hei  , Li Pei-Xian  , Huang Yun-Xia  , Li Gui-Fang  , Hao Yue  ,   School of Technical Physics, Xidian University, Xi'an 710071, China;,   Key Laboratory of Wide Band-gap Semiconductor Materials & Devices, Xidian University, Xi'an 710071, China
Published: December 2020

The electronic structure and permittivity of Al-doped 3C-SiC are studied by using the first principles plane-wave pseudopotential method based on the density functional theory, and compared with those of undoped 3C-SiC. Results show that the Fermi energy level introduced into valence band and band gap is slightly widened through Al doping for 3C-SiC, and that the permittivity is greatly improved in a frequency range of 8.2-12.4 GHz. Al doped 3C-SiC powder absorber is prepared by combustion synthesis, and the permittivities of the samples are measured in the frequency range of 8.2-12.4 GHz by vector network analyzer, which validates the results of theoretical calculation. The mechanism of microwave loss is discussed.
The enhancement of current in superconductor wires by modifying and changing the surface region microstructure
Authors: Guo Zhi-Chao  , Suo Hong-Li  ,   The Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

The electromagnetic characteristics of superconductor are briefly analyzed and described, when a magnetic field is applied to the superconductor, flux lines penetrate it from the surface. The flux lines are pinned by pinning centers on the surface of the superconductor, and cannot penetrate deeply from the surface and the density of the flux lines will be higher near the surface and lower in the inner region, with the participation of surface barrier effect and Meissner effect, which indicates the enhancement of pining in the core of the superconducting wire is useless and blocks the transport current. Based on this knowledge, the new multilayer structure wire is design, and the core of the wire is the high-density superconductor crystal covered by doping or changing microstructure layer with thickness as the penetration depth, outer part of the superconducting region is modified, by nanoparticle surface decorating, electron and heavy ion irradiation and extension to surface. Furthermore the Columnar defects, located near the surface, which suppress the surface barrier but create gigantic surface pinning, and the other pining centers have not this property. Then the superconducting region is wrapt by the normal metal.
Super broadband yellow emission glass suitable for white lighting
Authors: Liu Zi-Jun  , Yang Lü-Yun  , Chen Qiao-Qiao  , Yu Yang  , Dai Neng-Li  , Li Jin-Yan  ,   Wuhan National Laboratory for Optoelectronics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

We present a new glass able to produce ultra-broadband yellow fluorescence. The luminescence system is Ce3+ doped low silica calcium aluminosilica glass excited by blue light emitting diode (LED). The glass is prepared by the conventional melting process. We analyze the luminescence properties of the samples by measuring their absorption spectra, excitation spectra, fluorescence spectra. Furthermore, we study the influence of excitation wavelength on the fluorescence intensity and peak wavelength. The doped glass combined with blue LED to obtain the white lighting is achieved. Besides we calculate the Commission Internationale de I'Eclairage chromaticity coordinate. Therefore these glasses have large potentials to be used as white lighting phosphor materials.
Femtosecond laser induced silicon surface cone microstructures by covering transparent films
Authors: Li Bao-Jia  , Zhou Ming  , Zhang Wei  ,   School of Materials Science and Engineering, Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013, China
Published: December 2020

We investigate the effect of preparation parameters on the formation of microstructures created on a single crystal silicon wafer covered with a polyethylene terephthalate (PET) transparent film by femtosecond pulse laser with a central wavelength of 800 nm. The results reveal that formation of the cone microstructures depends on laser fluence, and the cone microstructures cannot be created by lower laser fluence or can be destroyed by higher laser fluence. The laser scanning speed can directly affect the quality of the cone microstructures, and lower speed will destroy the cone, while higher speed will create indistinct cone microstructures each with smaller depth. Some idealized structures are obtained by optimizing the experimental parameters. Finally, we find that the cone microstructures on silicon wafer covered with a film are caused by both laser ablation and oxidation, and laser ablation plays a major role.
The effect of electromagnetic compound field on the solidified microstructure of Zn-10 wt%Bi hyper-monotectic alloy
Authors: Zheng Tian-Xiang  , Zhong Yun-Bo  , Sun Zong-Qian  , Wang Jiang  , Wu Qiu-Fang  , Feng Mei-Long  , Ren Zhong-Ming  ,   Shanghai Key Laboratory of Modern Metallurgy & Material Process, Shanghai University, Shanghai 200072, China
Published: December 2020

The effects of different electro-magnetic body forces on the microstructure and solidifying process of Zn-10 wt%Bi hyper-monotectic alloy under the condition of high magnetic field are investigated in this paper. The result indicate, on the one hand, that the solidified structure is wanted most and the diameter of the second phase particle is minimum when the alternative current (50 Hz) increases to a certain value. On the other hand, the degree of segregation, dispersion and size of the second Bi phase particles in solidified structure of Zn-10 wt%Bi hyper-monotectic alloy are refined significantly with the increase of magnetic induction intensity under a fixed alternative current (50 Hz) value. The analysis result indicates that both the magnetic induction intensity and alternative current intensity have a significant effect on solidified structure so that we can obtain a more competitive solidified structure of monotectic alloy by controlling the intensity of magnetic induction and alternative current.
Error analysis of four-quadrant-based tracking sensor for inevitable crosstalk in multiple anode photomultiplier tube
Authors: Ma Xiao-Yu  , Guo You-Ming  , Rao Chang-Hui  , Wei Kai  , Tian Yu  , Rao Xue-Jun  ,   The laboratory on Adaptive Optics, 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;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Based on the basic principle of four-quadrant-based tracking sensor, the centroid detection error and the displacement sensitivity of four-quadrant detector, caused by noise or crosstalk in multiple anode photomultiplier (PMT tube), are analyzed in detail. The tracking error formula of four-quadrant-based tracking senor is given in theory and verified in experiment. The results show that when the photon-electron number per frame is constant, the tracking error of four-quadrant-based tracking senor increases as the crosstalk in multiple-anode PMT increases, and when the crosstalk in multiple-anode PMT is constant, the tracking error of four-quadrant-based tracking senor decreases as the photon-electron numbers increases.
Investigations on spectroscopic parameters and molecular constants of SO+ (b4∑-) cation
Authors: Xing Wei  , Liu Hui  , Shi De-Heng  , Sun Jin-Feng  , Zhu Zun-Lüe  ,   College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, China;,   College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The potential energy curve (PEC) of b4Σ- electronic state of the SO+ cation is calculated using the internally contracted multireference configuration interaction approach with the Davidson modification (MRCI+Q) for internuclear separations from 0.103 to 1.083 nm. The basis set used is a correlation- consistent aug-cc-pV5Z basis set. The spin-orbit coupling effect on the spectroscopic parameters is taken into account by the state interaction approach with the full Breit-Pauli operator with all-electron basis set, aug-cc-pCVTZ. To improve the quality of PEC and spin-orbit coupling constant, core-valence correlation and relativistic corrections are included. Core-valence correlation correction is calculated using a cc-pCVTZ basis set. Relativistic corrections are included by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. At the MRCI+Q/aug-cc-pV5Z+CV+DK level, the spin-orbit coupling constant of the SO+ (b4Σ-1/2,3/2) is 1 cm-1 when the aug-cc-pCVTZ basis set is used for the spin-orbit coupling calculations The spectroscopic parameters are determined and compared with those reported in the literature. Excellent agreement is found between the present results and the measurements. The vibrational level G(v) inertial rotation constant Bv and centrifugal distortion constant Dv are predicted for each vibrational state of the b4Σ- electronic state by solving the ro-vibrational Schrödinger equation of nuclear motion using Numerov's method and those of the first 2 vibrational states are reported for the non-rotation SO+ cation. Comparison with the measurements demonstrates that the present vibrational manifolds are both reliable and accurate. They should be good predictions for future experimental or theoretical research.
Orientation of ground-state CO (X1∑+) molecules by combined electrostatic and laser fields
Authors: Huang Yun-Xia  , Xu Shu-Wu  , Yang Xiao-Hua  ,   School of Science, Nantong University, Nantong 226007, China; State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
Published: December 2020

We investigate the orientation of the CO (X1∑+) molecules in the combined electrostatic and laser fields. We analyze the adiabatic and nonadiabatic interactions of the molecules with the applied laser field. It shows that the pendular energy levels induced by the laser field form the tunneling doublets which can be coupled by the applied electrostatic field. The CO molecules in the X1∑+ state with small permanent dipoles can be greatly orientated due to the coupling interaction. If the laser field is added adiabatically, the excellent orientation is achieved even at a weak electrostatic field. While in a nonadiabatic case, the molecular orientation reoccurs periodically when the laser field is turned off. Additionally, we study the dependence of the degree of the molecular orientation on the applied laser and electrostatic intensities and the molecular temperature.
Mechanism of directional cracking of Ti,C:sapphire crystal
Authors: Hu Ke-Yan  , Xu Jun  , Tang Hui-Li  , Li Hong-Jun  , Zou Yu-Qi  , Su Liang-Bi  , Chen Wei-Chao  , Zhang Bao-Hui  ,  Yang Qiu-Hong  ,   Department of Electronic Imformation Materials, Shanghai University, Shanghai 200720, China;,   Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

Directional cracking in Ti,C:sapphire crystals grown along [1120] by Vertical Bridgman method often occurs in the cutting and processing process. In this work, we discuss the characteristic and mechanism of directional cracking of Ti,C:sapphire, and find that directional cracking originates from (1100) lattice plane and spreads along [0001] orientation. Through the Crystalmaker Simulation software, we find that atomic arrangement on (1100) lattice plane is the most sparse and adjacent atomic spacing is the largest along vertical [0001] direction, so in the system (1100) [0001] of lattice has a minimum cracking strength. Irregular carbon inclusions in the cracked Ti,C:sapphire are observed with optical microscopy, scanning electron microscopy (SEM), and X-ray diffractometry. These inclusions cause great internal stress in the cooling process due to thermal expansion mismatch and cracking originating from and spreading in the weak system (1100) [0001] of lattice. As a consequence, macroscopic directional cracking is observed in the Ti,C:sapphire. The study has important theoretical and practical significance for growing high-quality Ti,C:sapphire crystal.
Dynamical behaviors of a bubble cluster under ultrasound field
Authors: Shen Zhuang-Zhi  , Wu Sheng-Ju  ,   Insitute of Applied Acoustics, Shaanxi Normal Unoversity, Shaanxi Institute of Physics, Key Laboratory of Ultrasonics of Shaanxi Province, Xian 710062, China
Published: December 2020

Considering liquid slight compressibility, the dynamical behaviors of a bubble cluster in an acoustic field are investigated by regarding water as a work medium. The effects of initial radius of gas bubble, the number of bubbles for monodisperse cluster and polysidperse cluster, acoustic frequency, acoustic pressure on bubble dynamics are numerically simulated. The effect of each parameter on bubble motion state and collapse pressure is analysed. Chaotic characteristics of bubble dynamics in monodisperse cluster are investigated. Two collapse pressure features under chaotic state are analysed. The results show that the suitable parameters are helpful for improving cavitation treatment effect.
Pulse loss front in coaxial cylinder vacuum magnetically insulated transmission lines under different voltages
Authors: Zhou Jun  , Zhang Peng-Fei  , Yang Hai-Liang  , Sun Jiang  , Sun Jian-Feng  , Su Zhao-Feng  , Liu Wan-Dong  ,   Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China;,   Northwest Institute of Nuclear Technology, Xi'an 710024, China
Published: December 2020

Based on the relativistic Brillouin flow theory, electron current and power loss in loss-front stage of coaxial cylinder vacuum magnetically insulated transmission line (MITL) are deduced under limiting current approximation. Through the particle-in-cell (PIC) model, loss currents and loss powers under different anode voltages are simulated. Simulation and theory results show that the proportions of loss current and loss power to the total current and power decrease when cathode-anode voltage increases. Beyond 4MV, limiting current approximation fits simulation results better than minimum current approximation. At voltages higher than 10 MV, relative error from limiting approximation is under 10%, while it exceeds 50% under minimum current approximation. This work is meaningful for establishing full circuit simulation of MITL system.
Modelling study of dielectric barrier glow discharge in Ar/NH3 mixture at atmospheric pressure
Authors: Zhang Zeng-Hui  , Zhang Guan-Jun  , Shao Xian-Jun  , Chang Zheng-Shi  , Peng Zhao-Yu  , Xu Hao  ,   State Key Lab of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

In order to investigate the mechanism of dielectric barrier glow discharge in Ar/NH3 mixture at atmospheric pressure, a multiple particles self-consistent coupled fluid model is proposed. And the finite-element method is used in the numerical calculation model, so the periodically varying waveforms of gas voltage, dielectric surface charge density and discharge current density are investigated. The spatial and temporal distributions of charged and neutral particles density and space electrical field strength are also obtained. The simulation results show that the periodic breakdown process of the gas gap is controlled by the gas voltage, and affected by dielectric surface charges. The spatiotemporal distributions of charged particle density and electrical field strength show that the discharge under conditions considered in this model is a typical atmospheric pressure glow discharge, and that in the discharge process there exist an obvious cathode fall region, a negative glow region, a Faraday dark space, and a positive column region. In the Ar/NH3 plasma, the dominant positive ions are NH3+, and the next ions are Ar2+; the dominant negative ions are NH2-; the main radical molecule products of ammonia decomposition are NH, NH2, and N2H3, but the main final stable products are N2 and H2.
Effects of cooling rates on microstructural evolution during solidification process of liquid Ca50Zn50 alloy
Authors: Zheng Nai-Chao  , Liu Hai-Rong  , Liu Rang-Su  , Liang Yong-Chao  , Mo Yun-Fei  , Zhou Qun-Yi  , Tian Ze-An  ,   School of Physics and Microelectronics Science, Hunan University, Changsha 410082, China;,   College of Materials Science and Engineering, Hunan University, Changsha 410082, China
Published: December 2020

A simulation study is performed on the effects of six different cooling rates on microstructural evolution during solidification process of liquid Ca50Zn50 alloy with larger atomic size difference by using the molecular dynamics method. The pair distribution function, Honeycutt-Andersen (HA) bond-type index method, cluster-type index method (CTIM-2) and three-dimensional visualization method are adopted to deeply analyze the microstructural evolution. The results show that there is a critical cooling rate (in a range of 11012 and 51011 K/s) for forming amorphous or crystal structure. When the cooling rate, such as 11014 K/s, 11013 K/s, 11012 K/s and 51011 K/s, is above the critical cooling rate, the amorphous structures are formed mainly to be the 1551, 1541 and 1431 bond-types or the icosahedron basic clustr (12 0 12 0 0 0); while the cooling rate is under the critical cooling rate, such as at 11012 K/s, the partial crystal structures are formed mainly to be the 1441 and 1661 bond-types or the bcc clusters (14 6 0 8 0 0) (containing part of hcp (12 0 0 0 6 6) and fcc (12 0 0 0 12 0) basic crystal clusters) in the system. In the cooling rate range of forming amorphous structure, the first peak of the pair distribution function g(r) is split obviously into three secondary peaks corresponding to the nearest neighbor as Zn-Zn, Ca-Zn and Ca-Ca, respectively, and with the decrease of cooling rate, the secondary peak formed by the like atoms is inereased and the secondary peak formed by unlike atoms is reduced. With the decrease of cooling rate, the Zn atoms can be easily segregated to form the larger clusters; the lower the cooling rate, the bigger the number of basic icosahedrons formed in the system, and the amorphous system is more stable. In the cooling rate range of forming crystal structure, a great number of Zn atoms are segregated to form the bulk bcc crystal structures and part of Ca atoms are segregated to form some hcp and fcc crystal clusters.
Density functional study on the stability and electronic structure of single layer Si6H4Ph2
Authors: Song Jian  , Li Feng  , Deng Kai-Ming  , Xiao Chuan-Yun  , Kan Er-Jun  , Lu Rui-Feng  , Wu Hai-Ping  ,   Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

The stability and electronic structure of Si6H4Ph2 are investigated by a comparative study of pure silicon nanosheet Si6, hydrogen-passivated silicon nanosheet Si6H6 and phenyl-passivated silicon nanosheet Si6H4Ph2 using density functional calculations. The mechanism on the stability of Si6H4Ph2 is elucidated. In addition, by examining the electronic structures of Si6H6 and Si6H4Ph2, we find the they both behave like an indirect gap semiconductor with a quite large gap.
Photoluminescence and Raman properties of Sb-doped ZnO thin film
Authors: Deng Quan  , Ma Yong  , Yang Xiao-Hong  , Ye Li-Juan  , Zhang Xue-Zhong  , Zhang Qi  , Fu Hong-Wei  ,   The Chongqing City Key Laboratory of Optoelectronic Functional Materials, Optical Engineering Key Lab, Chongqing Normal University, Chongqing 400047, China
Published: December 2020

Sb-doped ZnO thin films with various impurity content values are deposited on glass substrates by radio frequency magnetron sputtering medthods. The influences of Sb doping content on the microstructural, photoluminescence and Raman properties of ZnO film are systematically investigated by X-ray diffraction (XRD), transmission spectrum, photoluminescence (PL) spectrum and Raman scattering spectrum. The results indicate that ZnO thin film doped with Sb exhibits a hexagonal wurtzite structure with preferred c-axis orientation; The vibrational mode at 532 cm-1 induced by Sb dopant can be observed in the Raman spectrum of the Sb-doped ZnO thin film, which can be attributed to local vibrational mode (LVMSb-O) that are formed by substituting Sb for Zn substitution and bonding O in ZnO lattice. The strong violet emission peak located at 3.11 eV is observed only in Sb-doped ZnO thin film by photoluminescence. Conbining the Raman scattering spectrum with photoluminescence, it is concluded that the strong violet emission peak is relation to SbZn-O complex defect in ZnO:Sb film.
The mean extinction time and stability for a metapopulation system driven by colored cross-correlated noises
Authors: Wang Kang-Kang  , Liu Xian-Bin  , Yang Jian-Hua  ,   State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;,   School of Mathematics and Physics, Jiangsu University of Science and Technology, Zhenjiang 212003, China;,   School of Mechatronic and Engineering, China University of Mining and Technology, Xuzhou 221116, China
Published: December 2020

In this paper, the stability for a metapopulation system driven by colored cross-correlated noises is investigated based on the Levins model. The stationary probability distribution and the explicit expression of the mean extinction time are derived according to the Fokker-Planck equation. Numerical results show that in the case of colored correlation between two noises, the addictive noise and the multiplicative noise intensity weaken the stability of metapopulation, and the correlation strength enhances the stability of metapopulation. If the correlation strength between the two noises is negative, the mean extinction time is a decreasing function of intensities of the two noises, but a increasing function of correlation time; if the correlation strength between the two noises is positive, then the mean extinction time is a decreasing function of addictive noise intensity and correlation time, but a non-monotonic function of multiplicative noise intensity.
A high-compatibility low-bending-loss photonic crystal fiber with standard single mode fiber
Authors: Sheng Xin-Zhi  , Lou Shu-Qin  , Yin Guo-Lu  , Lu Wen-Liang  , Wang Xin  ,   School of Science, Beijing Jiaotong University, Beijing 100044, China;,   School of Electronic and Information Engineer, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

A high-compatibility low-bending-loss photonic crystal fiber (PCF) with standard single mode fiber (SMF) is designed and manufactured successfully. From the point of the view of fiber fabrication and application, a feasible structure with a germanium-doped core surrounded by one layer of six air holes running along fiber axis is adopted in fiber design. The properties of the fabricated PCF such as modal property, bending characteristic and dispersion are systemically evaluated with indirect measurement method. Analysis results demonstrate that this fiber has a mode field area of 79.26 μm2 and dispersion of 21.7 ps·km-1·nm-1, which exhibits high compatibility with SMF. The bending loss is 0.0365 dB/turn at a wavelength of 1550 nm for a bending radius of 5 mm, which is less than the bending loss of 0.5 dB/turn of G.657B. This fiber offers an efficient way to develop the low-bending-loss fibers for the application of fiber-to-the-home.
Study on the radius and energy transmission properties of lightning discharge channel by the spectra
Authors: Wang Xue-Juan  , Yuan Ping  , Cen Jian-Yong  , Zhang Ting-Long  , Xue Si-Min  , Zhao Jin-Cui  , Xu He  ,   Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China;,   Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730070, China
Published: December 2020

Combining the spectra of could-to-ground lightning discharge processes obtained by a slit-less spectrograph with the synchronous electrical information, the temperature, the linear charge density, the channels initial radius, the final radius and the energy per unit length are calculated. The results of these parameters are in agreement with the values reported in other work. The correlative analysis indicates that the arc initial radius mainly depends on the duration of the discharge current, the radius increases with temperature rising, and the total intensity of spectra is correlated positively with initial radius and energy per unit length. The energy per unit length is directly proportional to the square of initial radius.
A molecular dynamics simulation on the relationship between contact angle and solid-liquid interfacial thermal resistance
Authors: Ge Song  , Chen Min  ,   Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
Published: December 2020

With the fast development of nanotechnology, the solid-liquid interfacial thermal resistance draws increasing research interest due to its importance in nanoscale energy transport. The contact angle is an important quantity characterizing the interfacial properties and is easy to be measured experimentally. Previous researchers have tried to correlate the contact angle to the interfacial thermal resistance. Using molecular dynamics simulation, we have calculated the contact angle and interfacial thermal resistance at a solid/liquid interface and discuss the relationship between the two quantities. The solid/liquid bonding strength and the solid properties are varied to test their effects on both contact angle and interfacial thermal resistance. The simulation results demonstrate that with increasing solid/liquid bonding strength, both the contact angle and interfacial thermal resistance decrease. However, the bonding strength between solid atoms and the solid atomic mass influence the interfacial resistance remarkably while they have little effect on the contact angle. It is because the variations of the solid atomic mass and the bonding strength between solid atoms change the frequency distribution of the vibration of the solid atoms, resulting in a difference in the thermal vibrational coupling between solid and liquid atoms. Our study indicates that the interfacial thermal resistance is not only related to the interfacial solid-liquid bonding strength which is characterized by the contact angle, but also the thermal vibrational coupling between solid and liquid atoms. There is not a simple relationship between the contact angle and the interfacial thermal resistance. The contact angle could not be used as an exclusive criterion for solid-liquid interfacial resistance estimation.
Dynamical entanglement in the model of field interacted with atoms of a nonlinear medium
Authors: Yan Yuan  , Wei Hou  ,   College of physical science and techonoloy, Huazhong Normal University, Wuhan 430079, China
Published: December 2020

The dynamical entanglement in a model of the field interacted with atoms in a nonlinear medium is studied in terms of concurrence and the reduced Neumann entropy for the generalized binomial state of the field and the ground state of atoms. It is shown that concurrence is dominantly-positively correlated with the reduced Neumann entropy. The entanglement under suitable condition is nearly unchanged for a long time. This is useful for quantum information processing.
Thermal quantum discord in Heisenberg XXZ model under different magnetic field conditions
Authors: Xie Mei-Qiu  , Guo Bin  ,   School of Science, Wuhan University of Technology, Wuhan 430070, China
Published: December 2020

The quantum discord of a two-qubit one-dimonsional Heisenberg XXZ spinchain in thermal equilibrium depends on the temperature T, when subjected to different magnetic fields, with B1 and B2 acting separately on the qubit, is studied in this paper. Four cases are considered here: (1) B1=B2 = 0 (without magnetic field); (2) B1≠0,B2=0 (only one qubit in magnetic field); (3) B1=B2 (homogeneous magnetic field); (4) B1=-B2 (inhomogeneous magnetic field). The similarities and difference between quantum discord and quantum entanglement are calculated and discussed in detail. Results show that the quantum discord is more robust than quantum entanglement against temperature, and the effect of inhomogeneous magnetic field is preferable for the quantum communications and quantum information processing, as compared with the effect of homogeneous magnetic field.
Complicated behaviors and non-smooth bifurcation of a switching system with piecewise linearchaotic circuit
Authors: Wu Li-Feng  , Guan Yong  , Liu Yong  ,   College of Information Engineering, Capital Normal University, Beijing 100048, China;,   School of Mathematical Science, Yancheng Teachers University, Yancheng 224002, China
Published: December 2020

The complex dynamical and non-smooth bifurcations of a compound system with periodic switches between two piecewise linear chaotic circuits are investigated. Based on the analysis of equilibrium states, the conditions for Fold bifurcation and Hopf bifurcation are derived to explore the bifurcations of the compound system with periodic switches while there are different stable solutions in the two subsystems. Different types of oscillations of the swithing system are observed, and the mechanism is studied and presented. In the difference of periodic oscillations, the number of the swithing points increases doubly with the variation of the parameter, which leads from period-doubling bifurcation to chaos.
Joint compression and tree structure encryption algorithm based on EZW
Authors: Deng Hai-Tao  , Deng Jia-Xian  , Deng Xiao-Mei  ,   School of Information Science and Technology, Hainan University, Haikou 570228, China
Published: December 2020

A novel joint compression-encryption algorithm based on embedded zerotree wavelet (EZW) coding is proposed. Encryption process is performed before entropy coding. The principles of the context modification and the decision modification and described. Simulation results show that the proposed algorithm has a good effect on security, and has the same compression efficiency compared to the original image compression algorithm.
A 3D numerical simulation to study thesystem of gyrotron
Authors: Xia Meng-Zhong  , Liu Da-Gang  , Yan Yang  , Peng Kai  , Yang Chao  , Liu La-Qun  , Wang Hui-Hui  ,   Institute of Physical Electronics, University of Electronic Science and Technology Chengdu 610054, China
Published: December 2020

In order to break the limitation of gyrotron emission producing the ideal electron beam in the traditional gyrotron numerical simulation, this paper on the basis of theoretical analysis of structural parameters for the 94 GHz double-anode magnetron injection electron gun, by optimizing the grid plot of conformal FDTD algorithm, obtains the high-performance electron beam of the horizontal and vertical velocity ratio of 1.42 and the maximum velocity spread of 5.92%, By using the optimized electron gun to replace the traditional gy rotron emission in the numerical simulation of the gyrotron system and using the four-process parallel MPI in computation, we finally obtain a TE03 mode, 94 GHz, the average output power of about 40 kW, with on efficiency of 10.5% for the high-performance gyrotron oscillating tube.
Super-resolution focusing of time reversal electromagnetic waves in metal wire array medium
Authors: Zhou Hong-Cheng  , Wang Bing-Zhong  , Ding Shuai  , Ou Hai-Yan  ,   Institute of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

With an existing metal wire array structure, this paper verifies the temporal and spatial focusing properties of the time reversal techniques, and confirms the super-resolution focusing properties of the time reversal electromagnetic waves. Since the metal wire array can provide an evanescent-wave channel, by changing the signal incentives to the time reversal mirror (TRM), this paper achieves some satisfactory simulation results of subwavelength off-site imaging. The analysis and simulation results indicate that with time reversal technique, we can use traditional materials and equipment to achieve super-resolution confocal imaging in the far field, and extract and analyze the source signal at different positions.
Spin coherent-state transformation and analytical solutions of ground-state based on variational-method for spin-Bose models
Authors: Yang Xiao-Yong  , Xue Hai-Bin  , Liang Jiu-Qing  ,   Institute of Theoretical Physics, Shanxi University, Taiyuan 030006, China;,   College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China
Published: December 2020

We present a variational method for the ground-state solutions of the spin-Bose models by means of the spin coherent-state transformation. For the Jaynes-Cummings (J-C) models with and without the rotating-wave approximation, the ground-state energies obtained by this method are in perfect agreement with the results from numerical diagonalization in the whole region of the coupling between a light field and an atom. The present variational-method can be directly used to solve the ground-state energies of the Dicke models with arbitrary atom-numbers and furoher study the quantum phase transition; while the variational-method based on the Holstein-Primakoff transformation is only valid in principle for the thermodynamic limit with the atom-number tending to infinity.
Effects of system size on population behavior
Authors: Yi Qi-Zhi  , Du Yan  , Zhou Tian-Shou  ,   College of Mathematics and Information Science, Jiangxi Normal University, Nanchang 330022, China;,   College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, China;,   School of Mathematics and Computational Science, Sun Yat-Sen University, Guangzhou 510275, China
Published: December 2020

There are many factors to influence the population behavior of cells. Except for the ways of cellular communication and the cellular environment, Which have been considered in the previous studies, the number of cells (or system size) that has been little considered before is also an important factor. This article investigates effects of system size on clustering behavior in a synthetic multicellular system, where individual oscillators are an integration of repressilator and hysteresis-based oscillators and are coupled through a quorum-sensing mechanism. By bifurcation analysis and numerical simulation, we find that increasing the cell number not only can change the size of the stability interval of steady state clusters and induce new clustering behaviors, but also benefits the enlargement of the attraction basin of steady state clusters, implying that cell differentiation may be closely related to the system size. In addition, such an increase can greatly extend the kinds and coexisting modes of steady state and oscillatory clusters, which would provide a good basis for the adaptability of organisms to the environment. Our results have extended the connotation of dynamics of coupled systems and also may be the foundation for understanding multicellular phenomena.
High-gain reduced-order observer-based synchronization for a kind of uncertain chaotic system
Authors: Han Dong  , Zhu Fang-Lai  ,   College of Electronics and Information, Tongji University, Shanghai 200092, China
Published: December 2020

In this paper we consider the issues of chaos synchronization and chaos-based secure communication when the so-called observer matching condition is not satisfied. An auxiliary drive signal vector is introduced such that the observer matching condition is satisfied. High-gain observers are employed to estimate the auxiliary drive signals as well as their derivatives in a finite time by using the drive signals of original system. Then, a kind of reduced-order observer is constructed which can directly eliminate the influence of the non-linear part and the disturbances of the system. Based on the estimates of states as well as the estimates of the auxiliary signals and their derivatives, a kind of message information recovery method is proposed. Finally, the Rössler chaotic system is used as a simulation example to verify the effectiveness of the proposed method.
Simplified sampling models for digital hologram
Authors: Li Jun-Chang  , Lou Yu-Li  , Gui Jin-Bin  , Peng Zu-Jie  , Song Qing-He  ,   Faculty of Science, Kunming University of Science and Technology, Kunming 650093, China
Published: December 2020

There are two sampling models of digital hologram in digital holographic research. The complex mathematical operation is involved in these two models, thereby leading to different results frequently and inconvenient theoretical analysis and practical application. Based on the analysis of physical processes in recording digital hologram and the study on geometry structure of CCD detector, the two sampling models are simplified into the same mathematical expression in this paper. Through studying the simplified model with cosine series expansion of digital hologram and sampling theorem, it is shown that the model has clear physical meanings and can be used for application study conveniently. Using the simplified model, we study digital holographic recording system with optical system and exact wavefront reconstruction expression verified in experiment.
Influence of the longitudinal shift of the entrance plane on the propagation properties of beams in strongly nonlocal nonlinear medium
Authors: Lu Da-Quan  , Duan Qiu-Ling  , Zhan Qiang  ,   Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510631, China
Published: December 2020

Based on the approach of mode decomposition, the influence of the longitudinal shift of the entrance plane on the propagation properties of beams in strongly nonlocal nonlinear medium is analyzed. The shift of the entrance plane changes the order and the longitudinal position of beam patterns in a period, the size of patterns, and the radius of the cophasal surface. These properties can be described with a simple mathematical equation, therefore the beam solution after the entrance plane is shifted can be easily obtained from that before the entrance plane is shifted.