bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructures in polycrystalline pure copper induced by high-current pulsed electron beamdeformation structures
Authors: Guan Qing-Feng  , Gu Qian-Qian  , Li Yan  , Qiu Dong-Hua  , Peng Dong-Jin  , Wang Xue-Tao  ,   College of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China
Published: December 2020

In order to investigate the superfast deformation mechanism of metal, the high-current pulsed electron beam (HCPEB) technique is employed to irradiate the polycrystalline pure copper. The microstructure of the irradiated sublayer is investigated by using transmission electron microscopy. It is suggested that the stress with very high value and strain rate is introduced within the sublayer after HCPEB irradiation. The dislocation cell and the tangle dislocation formed by cross slip are the dominant defects after one-pulse HCPEB irradiation, whereas, dense dislocation walls and twins are the central microstructures after five- and ten-pulse irradiation. The diffusion and the climb of the atomic plane can cause the formation of the steps at the grain boundary and (or) the twin boundary. Based on the structure characteristics of the irradiated surface, the possible deformation mechanism induced by HCPEB irradiation is discussed.
First principles study of H2 molecule adsorption on Li3 N(110) surfaces
Authors: Chen Yu-Hong  , Du Rui  , Zhang Zhi-Long  , Wang Wei-Chao  , Zhang Cai-Rong  , Kang Long  , Luo Yong-Chun  ,   Key Laboratory of Advanced Non-ferrous Metal Materials of Gansu Province, Lanzhou University of Technology, Lanzhou 730050, China;,   School of Science, Lanzhou University of Technology, Lanzhou 730050, China
Published: December 2020

The adsorption of H2 on a Li3N(110) crystal surface is studied by first principles. Preferred adsorption sites, adsorption energy, dissociation energy and electronic structure of the H2/Li3N(110) systems are calculated separately. It is found that H2 is adsorbed on the N bridge site more favorably than on the other sites, while two NH radicles are formed on the Li3N(110) crystal surface. The calculated adsorption energy on the N bridge site is 1.909 eV, belonging to a strong chemical adsorption. The interaction between H2 and Li3N(110) surface is due mainly to the overlapping among H 1s, N 2s and N 2p states, through which covalent bonds are formed between N and H atoms. An activation barrier of 1.63 eV is found for the dissociation of H2 molecule in N bridge configuration, which indicates that the dissociative adsorption of H2 on Li3N(110) surface is favorable under the certain heat activation condition; NH2 radicle is formed after the optimization of H2 adsorbed on the N top site. The adsorption energy on the N top site is negative. In other words, this adsorption is unstable. So it is concluded that it is not easy to produce the LiNH2 between Li3N(110) face and H2 directly.
Microstructure and mechanical properties of Ti-B-C-N nanocomposite coatings
Authors: Luo Qing-Hong  , Lu Yong-Hao  , Lou Yan-Zhi  ,   Beijing Institute of Aeronautical Materials, Beijing 100095, China;,   Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Published: December 2020

Ti-B-C-N nanocomposite coatings with different C quantities are deposited on Si(100) and high speed steel (W18Cr4V) substrates by the closed-field unbalanced reactive magnetron sputtering in the mixture of argon, nitrogen and acetylene gases. The microstructures of Ti-B-C-N nanocomposite coatings are characterized by X-ray diffraction and high-resolution transmission electron microscopy; while the nanohardness and elastic modulus values are measured by the nano-indention method. The results indicate that in the studied composition range, the deposited Ti-B-C-N nanocomposite coatings are found still only in the TiN base nanocrystalline. When the C2H2 flux is small, adding C can promote crystallization of Ti-B-C-N nanocomposite coatings, and the grain can be increased to improve the mechanical properties, when the grain size of about 6 nm (C2H2 flux rate 2 cm3/min), hardness, elastic modulus and fracture toughness of Ti-B-C-N nanocomposite coatings achieve the maximum, respectively, 35.7 GPa, 363.1 GPa and 2.46 MPa m1/2; the further increase of the C content of Ti-B-C-N nanocomposite coating can reduce mechanical properties of coating dramatically.
Structure and mechanical property of glow discharge polymer
Authors: He Zhi-Bing  , Yang Zhi-Lin  , Yan Jian-Cheng  , Song Zhi-Min  , Lu Tie-Cheng  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China;,   College of Physical Science and Technology, Sichuan University, Chengdu 610065, China
Published: December 2020

Different glow discharge polymer (GDP) thin-films are prepared at various working pressures and flux ratios of trans-2-butune (T2B) to H2 by using low-pressure plasma enhanced chemical vapor deposition technology. Hydrogen atomic content and network structure of GDP thin-film are characterized by element analysis and Fourier transform infrared spectrum. The hardness and modulus of GDP coating are measured by nanoindentation. It is found that when working pressure and flux ratio between T2B and H2 gradually decrease, hydrogen content and sp3 CH3 groups decrease, sp2 CH2 and sp3 CH1,2 groups increase and hardness H and Youngs modulus E of GDP coating and the cross-linking degree of carbon network inerease.
Calculation of valence band structure of uniaxial 〈111〉 stressed silicon
Authors: Ma Jian-Li  , Zhang He-Ming  , Song Jian-Jun  , Wang Xiao-Yan  , Wang Guan-Yu  , Xu Xiao-Bo  ,   Key Laboratory for Wide Band Gap Semiconductor Materials and Devices of Ministry of Education, School of Microelectronics, Xidian University, Xi’an 710071, China
Published: December 2020

The valence band structure of uniaxial 〈111〉 stressed silicon is calculated in the frame of kp perturbation method and compared with that of unstressed silicon. The valence band energy level shifting, splitting, and variation of the effective mass in the vicinity of the point are presented for different uniaxail 〈111〉 stresses. The effective masses for the heavy and light hole bands in unstressed, our calculation results are in good agreement with the obtained published results of bulk silicon. The study extends the selective range of optimum stresses and crystal direction configuration of conduction channels for uniaxial stressed silicon devices. The obtained results of splitting energy and effective mass may serve as the reference for the calculation of other physical parameters of uniaxial 〈111〉 stressed silicon.
Synthesis and electrical properties of dual doped CaMnO3 based ceramics
Authors: Wang Hong-Chao  , Wang Chun-Lei  , Su Wen-Bin  , Liu Jian  , Sun Yi  , Peng Hua  , Zhang Jia-Liang  , Zhao Ming-Lei  , Li Ji-Chao  , Yin Na  , Mei Liang-Mo  ,   State Key Laboratory of Crystal Materials, School of Physics, Shandong University, Jinan 250100, China;,   Department of Physics, Changji University, Changji 831100, China
Published: December 2020

Different Nb doped Ca0.9Yb0.1Mn1-xNbxO3 ceramics are successfully synthesized by the conventional solid state reaction technique. The crystal structures are of orthorhombic phase, belonging to the Pnma space group. The lattice constant and the volume increase with the increase of Nb content. Relatively high density is around 97%. Scanning electron microscope (SEM) images show that samples are well crystallized. The electrical resistivity and the Seebeck coefficient are measured in a temperature range between 300 and 1100 K. At low temperatures, the electrical resistivity shows a semiconductive-like behavior. At high temperatures, the electrical resistivity exhibits a typical metallic conductive behavior. The semiconductor-metal transition temperature shifts toward a higher temperature with the increase of Nb content. The electrical resistivity increases with Nb dopant, except that the electrical resistivity for x=0.03 is slight lower than that fox x=0.00 sample at high temperature range. This conductivity behavior can be understood as the fact that though Nb doping can introduce more carriers, it also distorts the MnO6 octahedra, and causes the carrier localization. The values of Seebeck coefficient are all negative, indicative of an n-type electrical conduction. The absolute value of Seebeck coefficient increases with temperature increasing, but decreases with the increase of Nb content. The highest power factor is obtained to be 297 W/K2m at 497 K in the x=0.00 sample, and the power factor of this sample is less independent of temperature in the whole measured temperature range.
Influence of niobium doping on crystal structure and thermoelectric property of reduced titanium dioxide ceramics
Authors: Liu Jian  , Wang Chun-Lei  , Su Wen-Bin  , Wang Hong-Chao  , Zhang Jia-Liang  , Mei Liang-Mo  ,   State Key Laboratory of Crystal Materials, School of Physics, Shandong University, Jinan 250100, China
Published: December 2020

Titanium oxide ceramics doped with niobium is synthesized in reduced atmosphere at 1200 ℃ by conventional solid-state reaction technique. From their crystal structures determined by the powder X-ray diffraction(XRD), the samples have multiple-phase with low Nb concentration, but they have single tetragonal rutile phase when Nb content is larger than 0.02. The electrical conductivities, the Seebeck coefficients and the thermal conductivities of the samples with single phase are measured at a temperature range between room temperature and 900 K. The electrical conductivity and the Seebeck coefficient show non-metallic behaviors. According to the fitting, it is found that the samples show thermal-activation mechanism at low temperatures and small-polaron hopping conduction mechanism at high temperatures. Moreover, the analyses of XRD, electrical conductivity and Seebeck coefficient show that the concentration of oxygen vacancy decreases with Nb content increasing. Thermal conductivity decreases with temperature increasing, dominating by lattice thermal conductivity. In the measurement region, the figure of merit (ZT) reaches a highest value of 0.19 at 873 K in the Ti0.98Nb0.02O2- sample.
Preparation and electrical transport properties of Fe doped Ca1-xFexMnO3(x=00.12) oxide
Authors: Zhang Fei-Peng  , Zhang Xin  , Lu Qing-Mei  , Liu Yan-Qin  , Zhang Jiu-Xing  ,   Key Laboratory of Advanced Functional Materials of Ministry of Education, College of Material Science and Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

The Fe doped Ca1-xFexMnO3(x=00.12) powder and bulk samples are fabricated by citric acid sol-gel and ceramic preparation process, the samples are analzed by X-ray diffraction pattern and electrical constant measurement. The results show that all samples are of single phase, the lattice constants are gradually lowered by Fe doping for Ca site, and the crystalline grain growth is restrained. All the bulk samples have semiconductor transporting characteristics in the whole temperature range of measurement. The transportation mechanism is not changed. The energy for polarons to hop is increased for doped samples and thus the electrical resistivity is increased by increasing Fe doping concentration.
Relationship between light efficiency and juction temperature of high power AlGaInP light-emitting diode
Authors: Chen Yi-Xin  , Shen Guang-Di  , Gao Zhi-Yuan  , Guo Wei-Ling  , Zhang Guang-Chen  , Han Jun  , Zhu Yan-Xu  ,   Beijing Optoelectronic Technology Laboratory, Beijing University of Technology, Beijing 100124, China
Published: December 2020

One of the main problems of high power AlGaInP light-emitting diode (LED) is the heat generated seriously at large working current, which is caused by the weak current spreading, the photon blocking and absorbing of p-type or n-type electrode, and the critical reflection at the interface between the device and air. The heat inside can lead to the restriction on light output, and gives rise to low light efficiency and the low luminous intensity. In this paper, we introduce a new LED structure which is composed of compound current spreading layers and compound distribute Bragg reflector (DBR) layers. For the new structure LED, the injected current spreads adequately and the reflectivity is improved by the compound DBR layers. The testing results show that the performance of new structure LED is much better than that of the conventional LED, and that at a working current of 350 mA, the output powers of the two kinds of LEDs (which are unpackaged) are 17 and 49.48 mW respectively. At the same time, the heat testing results show the relationship between LED light efficiency and juction temperature, and the consistence between the juction temperature ratio and the ratio of light efficiency for the two kinds LEDs, which implies that LED light efficiency can be improved by reducing heat generated inside and reducing the juction temperature.
Local lattice structure and spin singlet contribution to zero-field splitting of ZnS:Cr2+
Authors: Lu Cheng  , Wang Li  , Lu Zhi-Wen  , Song Hai-Zhen  , Li Gen-Quan  ,   College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, China
Published: December 2020

Using the unified ligand-field-coupling scheme, the 210210 complete energy matrices including all the spin states for d4 configuration transition metal ions are constructed within a strong field representation. By diagonalizing the complete energy matrices, the local lattice structure and the Jahn-Teller energy of Cr2+ ions doped into ZnS are investigated. It is found that the theoretical results are in good agreement with the experimental data. Moreover, the contribution of the spin singlet to the zero-field splitting (ZFS) parameter of Cr2+ ions doped into ZnS is also investigated. The results indicate that the spin singlet contribution to ZFS parameter D is negligible, but the contribution to ZFS parameters a and F may not be neglected.
Excitation spectrum intensity adjustment of SrWO4:Eu3+ red phosphors for light-emitting diode
Authors: Ren Yan-Dong  , Lü Shu-Chen  ,   College of Physics and Electronic Engineering, Harbin Normal University, Harbin 150080, China
Published: December 2020

The SrWO4:Eu3+ red phosphors with different Eu3+ doping concentrations and different sintering temperatures are prepared by the co-precipitation method. The powders as-prepared exhibit sharply red characteristic emissions of Eu3+ ions at room temperature. The near-ultraviolet and blue light absorption intensities are controlled by adjusting sintering temperature and doping concentration and so the red emission intensities under the 395 or 465 nm excitation can be adjusted. Our results show that the SrWO4:Eu3+ red phosphors can be effectively excited by the ultraviolet light, the near-ultraviolet (395 nm) light and 465 nm blue light. Therefore the SrWO4:Eu3+ red phosphors may have a potential application to white light-emitting diodes.
Investigation on the band structures of AlN/InN and AlN/GaN superlattices
Authors: Lu Wei  , Xu Ming  , Wei Yi  , He Lin  ,   Institute of Solid State Physics, Sichuan Normal University, Chengdu 610101, China
Published: December 2020

The band structures of wurtzite-AlN/InN and AlN/GaN superlattices are calculated by the Krnig-Penney model and the deformation potential theory under considering the lattice strain. Our calculations include the variation of band structure with the parameters for the sublayers, and the energy dispersion relations. It is found that by varying the sublayer thickness, the band structures can be well designed in different ways. The strain will change the bandgaps, reduce the band offsets and the sub-bands obviously, and make the valence band more complex. In comparison with the experimental results, our model is rather suited for simulating the narrow-quantum-well structures, while for the wide-quantum-well structures, the build-in field should be considered.
Growth of Ge quantum dot at the mix-crystal interface self-induced on the ion beam sputtering deposition
Authors: Xiong Fei  , Pan Hong-Xing  , Zhang Hui  , Yang Yu  ,   Research Institute of Engineering and Technology, Yunnan University, Kunming 650091, China;,   Institute of Advanced Materials for Photo-electronics, Kunming University of Science and Technology, Kunming 650093, China
Published: December 2020

The dense domes of Ge quantum dots on Si (001) substrate with a monomodal morphology distribution are deposited at different temperatures by ion beam sputtering (IBS). The areal density of the Ge quantum dots is observed to increase with elevating temperature, but the dots size to decrease. As the deposition temperature increases to 750 ℃, the smaller Ge quantum dots each with a height of 14.5 nm and base width of 52.7 nm are obtained by sputtering 15 monolayer Ge coverage, and the dots areal density is up to 1.681010 cm-2 at the same time. Thus the evolution of Ge quantum dot prepared by IBS is very different from that by vapor deposition at thermal equilibrium condition. The stable shape and the size distribution are demonstrated to result from the kinetic behavior of the surface atoms which is restricted by the thermodynamic limitations. A mix-crystal interface including amorphous and crystal components is revealed by Raman spectrum, and this special interface is demonstrated to contribute to the high density of Ge quantum dots, since the boundaries between the two different components can provide more preferential centers for the nucleation. As the density increases at high deposition temperature, the elastic repulsion between islands is enhanced, resulting in the surface atoms growing along the orientation of high index during the IBS deposition, and inducing the increase in aspect ratio and the reduction in island size.
Simulation of multi-grain solidification and subsequent spinodal decomposition by using phase field crystal model
Authors: Zhang Qi  , Wang Jin-Cheng  , Zhang Ya-Cong  , Yang Gen-Cang  ,   State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China
Published: December 2020

The phase field crystal model (PFCM) is employed to simulate the process of multi-grain solidification and its subsequent spinodal decomposition in a binary alloy system. Simulation results show that the PFCM can reproduce the whole process of the important material processing phenomena of multi-grain solidification, including nucleation, growth, coarsening and grain boundary formation. Furthermore, the PFCM can also successfully simulate the full course of the multi phase transformation process from solidification to spinodal decomposition.
Detection of seam tracking offset based on infrared image during high-power fiber laser welding
Authors: Gao Xiang-Dong  , Mo Ling  , Zhong Xun-Gao  , You De-Yong  , Katayama Seiji  ,   Faculty of Mechanical and Electrical Engineering, Guangdong University of Technology, Guangzhou 510006, China;,   Joining and Welding Research Institute, Osaka University, Osaka 567-0047, Japan
Published: December 2020

Seam tracking is a significant precondition to obtain good welding quality. During the laser welding, the laser beam focus must be controlled to follow the welding seam accurately. A novel approach to detecting the offset between the laser beam focus and the welding seam based on infrared image processing is investigated during high-power fiber laser butt-joint welding of type 304 austenitic stainless steel plates at a continuous wave fiber laser power of 10 kW. The joint gap width is less than 0.1 mm. An infrared sensitive high speed camera arranged in off-axis direction of laser beam is used to capture the dynamic thermal images of a molten pool. The characteristics of thermal distribution and infrared radiation of the molten pool, when the laser beam focus is deviated from the welding seam center, are analyzed. Two parameters called the keyhole morphological parameter and the heat accumulation effect parameter are defined as the characteristic values of seam tracking offset to determine the offset between the laser beam focus and the desired welding seam. Also, the image processing technique is used to analyze the infrared images of the molten pool, which indicates the presence of mathematic correlation between the defined two parameters and the seam tracking offset. The welding experiments confirm that the offset between the laser beam focus and the welding seam can be estimated by the keyhole morphological parameter and the heat accumulation effect parameter effectively.
A quasi transverse electromagnetic mode waveguide developed by using metal-patch electromagnetic bandgap structure
Authors: Ren Li-Hong  , Luo Ji-Run  , Zhang Chi  ,   Key Laboratory of High Power Microwave Sources and Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China;,   Graduate University of Chinese Academy of Sciences, Beijing 100049, China;,   Datang Mobile Communications Equipment Company Limited, Beijing 100083, China
Published: December 2020

To solve the narrow operation-band of the electromagnetic bandgap (EBG) waveguide, a quasi transverse electromagnetic (TEM) mode waveguide using the metal-patch EBG structure as sidewall is proposed in this paper. Theoretical analysis and numerical calculation show that broader bandwidth, better transportation property, and more uniform electric field distribution of the quasi-TEM mode can be reached. Simulation results using Ansoft HFSS indicate that the metal-patch EBG structure can convert TE10 mode into quasi-TEM mode in the central frequency of 14 GHz with a bandwidth of 1.7 GHz and the uniformity of electric field distribution reaches 84.7% in 83.9% cross section area.
Radiation-resistant bipolar n-p-n transistor
Authors: Zhai Ya-Hong  , Li Ping  , Zhang Guo-Jun  , Luo Yu-Xiang  , Fan Xue  , Hu Bin  , Li Jun-Hong  , Zhang Jian  , Su Ping  ,   State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Bipolar n-p-n transistor geometrical parameters are optimized based on the principle of minimizing the perimeter-to-area ratio (P/A). Three types of radiation-resistant n-p-n transistors are developed and fabricated in the 20 V bipolar process. The first is emitter-base junction hardened n-p-n transistor. The second has heavily boron doped base ring. And the last uses both radiation-resistant measurements. The experimental results indicate that after irradiated by the radiation of total dose of 1 kGy, in current gain, the common n-p-n(unhardened) transistor reduces about 60%65%, while the first two hardened n-p-n transistors increases 10%15%: the last hardened n-p-n transistors are 15%20% greater than the common n-p-n transistors in current gain.
Influence of time delay on global temperature correlation
Authors: Zhi Rong  , Gong Zhi-Qiang  , Wang Qi-Guang  , Xiong Kai-Guo  ,   (1)College of Atmospheric Science, Lanzhou University, Lanzhou 730000, China; (2)Laboratory for Climate Studies of China Meteorological Administration, Beijing 100081, China; (3)Laboratory for Climate Studies of China Meteorological Administration, Beijing 100081, China; College of Atmospheric Science, Lanzhou University, Lanzhou 730000, China
Published: December 2020

With time delay under consideration, temperature correlation matrixes are constructed based on the reanalysis of temperature data provided by National Centers for Environmental Prediction/National Center for Atmospheric Research and European Centre for Medium-Range Weather Forecasts. Results indicate that the correlation of global temperature decreases with lag time, and the rate is dependent on time lag. We divide the lag time (1—30 d) into three segments, i.e., 1—7 d, 8—20 d and 21—30 d according to the decrease rate of global average correlation coefficient Cglb. When the lag time is in a specific interval (8—20 d), Cglb is unstable, which may explain the difficulty in long range weather forecast of 10—30 d. The spatial distribution of the global temperature correlation keeps stable for different lag times, while the numerical change shows zonal distribution on the whole, and that the most of Asia and the equatorial central and eastern Pacific show countertrend to other parts of similar latitudes.
New infinite sequence exact solutions of nonlinear evolution equations with variable coefficients by the second kind of elliptic equation
Authors: Taogetusang  , Narenmandula  ,   (1)College of Physics and Electronics, Inner Mongolia University for Nationalities, Tongliao 028043, China; (2)The College of Mathematical Science, Inner Mongolia Normal University, Huhhot 010022, China
Published: December 2020

In the paper, to construct new infinite sequence exact solutions of nonlinear evolution equations, several kinds of new solutions of the second kind of elliptic equation Bäcklund transformation are proposed. The KdV equation containing variable coefficients and forcible term, combined with (2+1)-dimensional and (3+1)-dimensional Zakharov-Kuznetsov equation with variable coefficients is taken as example to construct new infinite sequence exact solutions of these equations with the help of symbolic computation system Mathematica, which include infinite sequence compact soliton solutions of Jacobi elliptic function and triangular function, and infinite sequence peak soliton solutions.
Travelling wave solution of disturbed Vakhnenko equation for physical model
Authors: Mo Jia-Qi  ,   Department of Mathematics, Anhui Normal University, Wuhu 241003, China;Institute of Medical Imaging Technology, University of Shanghai Science and Technology, Shanghai 200093, China;Division of Computational Science, E-Institutes of Shanghai Universities at SJTU, Shanghai 200240,China
Published: December 2020

A kind of disturbed Vakhnemko equation is considered. The modified asymptotic method is given. Firstly, we obtain corresponding traveling wave solution of the typical Vakhnemko equation. Secondly, introducing a functional, constructing the iteration expansion of solution, the nonlinear equation is converted into a set of iteration sequence. And then, the corresponding approximations of solution are solved successively. Finally, the approximate expansion for arbitrary order accuracy of the travelling wave solution for the original disturbed Vakhnemko model is obtained and its accuracy is discussed.
A new algorithm of calculating eigenmodes of gyrotron resonators
Authors: Liu Rui  , Li Hong-Fu  , Niu Xin-Jian  ,   Vacuum Electronics National Laboratory, Institute of High Energy Electronics, UESTC, Chengdu 610054, China
Published: December 2020

According to Runge-Kutta theory, in this paper we present a new algorithm of calculating the eigenmodes of gyrotron resonators. Different from in the traditional algorithm, all properties of the eigenmodes can be determined by solving the minimum of a function with two variables, namely the resonant frequency and Q factor, in the new algorithm. Through examples of numerical calculation, it is verified that the calculation efficiency of the new algorithm is much higher than the traditional algorithm.
Fidelity of quantum teleportation of atomic-state in dissipative environment
Authors: Fang Mao-Fa  , Peng Xiao-Fang  , Liao Xiang-Ping  , Pan Chang-Ning  , Fang Jian-Shu  ,   (1)College of Physics and Information Science, Hunan Normal University, Changsha 410081, China; (2)College of Science, Central South University of Forestry and Technology, Changsha 410004, China; (3)School of Science, Hunan University of Technology, Zhuzhou 412008, China
Published: December 2020

The atomic-state quantum teleportation in a dissipative environment is investigated by the quantum theory of damping - density operator approach and the numerical calculations. The effects of fidelity for different initial atomic-states are discussed. The results show that, when only the input atomic-state is exposed to the squeezed vacuum reservoirs, the fidelity of atomic-state with larger probability in the ground state is larger than that of other state; on the other hand, when the quantum channel is exposed to the reservoirs, the input state with equal probability in the ground state and the excited state has the largest fidelity in all the teleported states.
Solidification transformation of benzene under quasi-isentropic compression
Authors: Cheng Xiao-Li  , Liu Fu-Sheng  , Li Yong-Hong  , Peng Xiao-Juan  , Zhang Ming-Jian  ,   Laboratory of High Pressure Physics, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

Kinetics of solidification of liquid benzene under high pressure has attracted much attention of scientists, and it is also one of long-standing disputes. In the present work, the gas-gun technique is combined with a recently developed measurement method of light transmittance, and the time dependence of light transmittance of liquid benzene is directly observed during successive multiply shock-compressions. The analysis shows that the transmittance decrease is caused by light scattering effects in a non-uniform optical medium, which is formed by local phase transformation of liquid-solid, and that the scattering feature reflects both the time relaxation and the spacial accumulation of transition process. The argument whether the liquid-solid phase transformation happens under multi-shock compression is clarified, and important experimental evidence is provided for the study of phase transformation Kinetics.
Comparison of second-order mixed symplectic integrator between semi-implicit Euler method and implicit midpoint rule
Authors: Zhong Shuang-Ying  , Wu Xin  ,   Department of Physics, Nanchang University, Nanchang 330031, China
Published: December 2020

When a Hamiltonian can be split into integrable and nonintegrable parts, the former part is solved analytically, and the latter one is integrated numerically by means of implicit symplectic integrators such as the first-order semi-implicit Euler method or the second-order implicit midpoint rule. These analytical and numerical solutions are used to construct a second-order mixed symplectic integrator with the semi-implicit Euler method and one with the implicit midpoint rule. A theoretical analysis shows that the Euler mixed integrator is inferior to the midpoint one in the sense of numerical stability. Numerical simulations of the circularly-restricted three-body problem also support this fact. It is further shown through numerical integrations of the post-Newtonian Hamiltonian of spinning compact binaries that the qualities of the Euler mixed integrator and the midpoint mixed method do depend on the type of orbits. Especially for chaotic orbits, the Euler mixed integrator often becomes unstable. In addition, the Euler mixed integrator has an advantage over the midpoint mixed method in computational efficiency, and is almost equivalent to the latter in the numerical accuracy if the two mixed integrators are stable. In spite of this, the midpoint mixed integrator is worth recommending for the study of the dynamics of post-Newtonian Hamiltonians of spinning compact binaries.
Hawking radiation in a dynamical Kerr black hole using a new tortoise coordinate
Authors: Xie Zhi-Kun  ,   Department of Physics and Electronic Information,Shaoxing University,Shaoxing 312000,China
Published: December 2020

Hawking radiation from a dynamical Kerr black hole is investigated using a new tortoise coordinate and the improved Damour-Ruffini method. The local temperature changing with time and latitude angle and the Hawking radiation with quasi-blackbody spectrum are obtained. The present results are different from the existing results obtained by using usual tortoise coordinate. There exists a certain problem in dimension for the usual tortoise coordinate and the present results may be more reasonable.
Analysis of oscillation phenomenon in digital controlled DC-AC H-bridge inverter
Authors: Lei Bo  , Xiao Guo-Chun  , Wu Xuan-Lü  , Qi Yuan-Rui  ,   State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering,Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

The discrete-time iterative map of digitally controlled DC-AC H-bridge inverter with outer load-voltage loop and inter inductance-current loop plus voltage-reference feedforward loop is derived by considering the effect of the time delay problems inherent in digital control system. The type of the bifurcation point when the system loses stability is predicted in terms of the eigenvalues of the Jacobian matrix,and it is found that the type is of the Hopf bifurcation. The analytic expressions of the stability boundaries and the oscillation frequency are deduced, and the underlying mechanism of this nonlinear phenomenon is analyzed. Finally, the theoretical results are verified by simulations and circuit experiments.
Scroll number and distribution control of attractor: system design and circuit realization
Authors: Liu Zhong  , Wu Hua-Gan  , Bao Bo-Cheng  ,   (1)Department of Electronic Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; (2)School of Information Science and Engineering, Changzhou University, Changzhou 213164, China
Published: December 2020

Through introducing two piecewise-linear functions into a three-dimensional linear system, a grid-scroll chaotic system with relatively simple algebraic of system structure is constructed. By deploying the zero points of the introduced saw-tooth function and modified saw-tooth function, the designs of the number and the distribution of the index-2 equilibrium points of the system are performed, and the controls of the scroll number and the scroll distribution of the chaotic attractor generated from the system are achieved. By using analog components such as operational amplifier, multiplier, etc., the saw-tooth function circuit, the modified saw-tooth function circuit and the three-dimensional linear system circuit are designed and the proposed grid-scroll chaotic system is implemented. The experimental results are in agreement with both theoretical analyses and numerical simulations, which verify the feasibility of the designs of the scroll number and scroll distribution of chaotic attractors.
Parameter identification and synchronization of spatiotemporal chaos in globally coupled network
Authors: Lü Ling  , Li Gang  , Zhang Meng  , Li Yu-Shan  , Wei Lin-Ling  , Yu Miao  ,   College of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China
Published: December 2020

Synchronization and parameter identification of globally coupled network constructed by discrete spatiotemporal chaos systems with unknown parameters are studied. The control law designed by Milosavljevic is extended, and applied to the identification of unknown parameters in spatiotemporal chaos systems at the nodes of the network and the study of global synchronization of the network. The one-dimensional convective equation with spatiotemporal chaos behaviour in physics is further taken for example to imitate analysis.
Melnikov chaos in Duffing-Rayleigh oscillator subjected to combined bounded noise and harmonic excitations
Authors: Feng Jun  , Xu Wei  , Gu Ren-Cai  , Di Gen-Hu  ,   Department of Applied Mathematics, Northwestern Polytechnical University, Xi'an 710129, China
Published: December 2020

In this paper,the dynamic behavior of Duffing-Rayleigh oscillator subjected to combined bounded noise and harmonic excitations is investigated. Theoretically, the random Melnikov's method is used to establish the conditions of existence of chaotic motion. The result implies that the chaotic motion of the system turns into the periodic motion with the increase of nonlinear damping parameter, and the threshold of random excitation amplitude for the system to change from chaotic to periodic motion in the oscillator turns from increasing to constant as the intensity of the noise increases. Numerically,the largest Lyapunov exponents and the Poincare maps are also used for verifying the conclusion.
Error analysis of correlating Shack-Hartmann wave-front sensor for a point source
Authors: Chen Lin-Hui  , Rao Chang-Hui  ,   (1)The Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu 610209, China;Institute of Optics and Electronics, Chinese Academy of Sciences. Chengdu 610209, China; (2)The Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu 610209, China;Institute of Optics and Electronics, Chinese Academy of Sciences. Chengdu 610209, China;Graduate School of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In Shack-Hartmann wavefront sensor(SH-WFS) based adaptive optics system, the centroiding algorithm is usually used to estimate the centroid of a point source spot. But the detecting accuracy of the centroiding algorithm is affected by many factors such as threshold selection, so that the centroid position of the spot cannot be evaluated accurataly under the condition of low signal-to-noise ratio(SNR) . Comparatively the correlating algorithm for Shack-Hartmann wave front-sensing is more robust because it need not reduce the thresholding. In this paper, based on the the principle of the correlating SH-WFS, the measurement error of the correlating SH-WFS is derived by building up the noise model of the correlating SH-WFS. The influences of spot size, photon noise, read out noise and background light noise on the measurement of the correlating SH-WFS are analyzed systematically. The numerically simulation results and the experimental results are consistent well with the theoretical analyses.
Coaxial Bragg reflector with small tapered inner rode corrugated ripples and phase matching section
Authors: Lan Feng  , Yang Zi-Qiang  , Shi Zong-Jun  ,   Research Institute of High Energy Electronics, College of Physical Electronics University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

A coaxial Bragg reflector with tapered inner rode corrugated ripples and phase matching section used in relativistic diffraction generator (RDG) with overmode cylindrical structure in Ka-band is presented and analyzed in this paper. The conservation of complex power technique(CCPT) is introduced to analyze the frequency response of the Bragg reflector. The influences of the phase matching section length, the corrugated sinusoidal slots depth and the tapered angle of the reflector on frequency response are studied. It is found by analyzing the influence of the initial ripple phase that the reflector has a favourable characteristic for mode selection. The research results provide important theoretical analysis and data reference for designing coaxial Bragg reflector structure.
Numerical simulation and study of electron cyclotron maser
Authors: Peng Kai  , Liu Da-Gang  , Liao Chen  , Liu Sheng-Gang  ,   School of Physical Electronics,University of Eelectronic Science and Technology of China,Chengdu 610054,China
Published: December 2020

In this paper,we develop a numerical model of electron cyclotron emission in three-dimensional Yee grid model, combine the FDTD algorithm to simulate electron cyclotron maser, and use the MPI parallel lgorithms to drastically reduce cmputation time. Finally, we simulate a 94GHZ Gyrotron oscillator, and verify its correctness through spectrum, power, operating mode.
Calculation of electronic equation of state(EOS) of gold at arbitrary temperature and matter density in improved atomic model
Authors: Zhu Xi-Rui  , Meng Xu-Jun  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100088,China
Published: December 2020

Based on the improved atomic model with considering temperature and density, the density distribution of the free electrons is dealt with by partial wave method based on the central field approximation. By an average of approximate treatment, the energy band split is given. In the atomic structure of the self-consistent calculation the band overlap is used as the free electron dynamic criterion. Electronic pressure, energy, heat capacity and other thermodynamic factors of gold are calculated
The role of multi-return induced collision-ionization in atomic nonsequential double ionization
Authors: Ye Di-Fa  , Liu Jie  , Xin Guo-Guo  , Zhao Qing  ,   (1)Institute of Applied Physics and Computational Mathematics, Beijing 100088, China; (2)School of Science, Beijing Institute of Technology, Beijing 100081, China; (3)School of Science, Beijing Institute of Technology, Beijing 100081, China;Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

The nonsequential double ionization of helium by high-intensity (1.5×1015 W/cm2) few-cycle laser pulses is investigated using a three-dimensional semi-classical rescattering model, with emphasis on the longitudinal correlated momentum spectra. We find that the percentage of opposite-hemisphere emission in this case is remarkably higher than those produced by laser pulses with medium-intensity (e.g., 7×1014 W/cm2) and low-intensity (e.g., 2.5×1014 W/cm2) those procuced by the laser pulses pulses with, and also the same intensies but longer laser pulses. Meanwhile, the V-shape structure is more pronounced. We identify the underlying mechanisms with tracing back the individual trajectories, and find that the single-and the multi-return induced collision-ionization are mainly responsible for the opposite- and the same-hemisphere emission, respectively. The dependences of these two different mechanisms on peak intensity and pulse length are predicted.
Direct fabrication of terahertz dual-band resonator
Authors: Zhao Dong-Mei  , Shi Yu-Lei  , Zhou Qing-Li  , Li Lei  , Sun Hui-Juan  , Zhang Cun-Lin  ,   (1)Basic Course Department of Beijing Union University, Beijing 100101, China;School of optoelectronics of Beijing Institute of Technology, Beijing 100081, China;School of optoelectronics of Beijing Institute of Technology, Beijing 100081, China; (2)Beijing Key Laboratory for Terahertz Spectroscopy and Imaging,Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100037, China
Published: December 2020

This paper deals with the dual- band response of double ring metal array structure and anti-double ring structure in a terahertz wave range. The two samples are complementary in structure and their responses in the terahertz band are also complementary. The double ring structure shows two absorption crests and the anti-double ring structure shows two corresponding peaks at the same frequencies. The inner ring of the double ring structure is a source of high-frequency response, while the outer ring leads to the low-frequency vibration. Therefore, we can change the inner and the outer ring size respectively to control the terahertz response. And this response is unaffected by the period of the structure. The double ring structures provide a new method to produce multi-frequency terahertz resonator.
Dissociative ionization of methane by 54 eV electron impact
Authors: J. Ullrich  , A. Dorn  , Ma Xin-Wen  , Xu Shen-Yue  , Ren Xue-Guang  , T. Pflüger  ,   (1)Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (2)Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China;Max-Planck-Institut für Kernphysik, Saupfercheckweg1, 69117 Heidelberg, Germany;Graduate University of Chinese Academy of Sciences, Beijing 100049, China; (3)Max-Planck-Institut für Kernphysik, Saupfercheckweg1, 69117 Heidelberg, Germany
Published: December 2020

The dissociative ionization process of methane induced by 54eV electron impact is investigated using an advanced reaction microscope. In the present paper, our attention is specially paid to the kinetic energy distributions of the CH+2,CH+ and C+ fragments. Energy deposition spectra are presented for these fragments of different kinetic energies. It is shown that the dissociations from the (2a1) -1 and (1t2) -2(3a1) states of CH+4 are the dominant contributions of the CH+2, CH+ and C+ fragments. The kinetic energy of fragment is sensitive to the electronic state of its parent ion. Fragment ions with kinetic energies lower than 0.1 eV are mainly from the dissociation of (2a1) -1 state, and partly from the dissociation of (1t2) -2(3a1) state; the ions with energies between 0.1 eV and 0.3 eV are contrituted equally by the two states; the ions with energies higher than 0.4 eV are formed dominantly from the dissociation of (1t2) -2(3a1) state.
A novel fast algorithm of electromagnetic dyadic Green's function in horizontal layered medium
Authors: Chen Gui-Bo  , Bi Juan  , Wang Jian-Bo  , Chen Xin-Yi  , Sun Guan-Cheng  , Lu Jun  ,   College of Science, Changchun University of Science and Technology, Changchun 130022, China
Published: December 2020

In this paper, a novel fast algorithm is presented for electromagnetic (EM) dyadic Green’s functions in horizontal layered medium using direct-waves’ extraction combining with self-adaptive digital filter method. First of all, the direct-waves which characterize effects of homogeneous medium in spectral domain Green’s functions(SDGF) are extracted, and their integrals are obtained by analytical calculations. In this method, the singularity of SDGF is reduced and the integral convergence range is shortened remarkably. Then, we transform the remnant integrals of SDGF into three rapid declining integrals, and self-adaptive digital filter method is introduced to obtain solution quickly. Finally, our numerical results validate the efficiency of the algorithm.
Design and simulation of a spherical electromagnetic reshaper with a split -ring- resonator microstructure
Authors: Li Yun  , Sun Hua  ,   Department of Physics and Jiangsu Province Key Laboratory of Thin Films,Suzhou University, Suzhou 215006, China
Published: December 2020

Reduced permittivity and permeability profiles are proposed based on the electromagnetic transformation theory to achieve spherical reshapers with a split-ring-resonator(SRRs) microstructure. The effective radial permittivity distribution depending on the structure parameters, is obtained to implement a reshaper impinged by a TE incident wave. Finite-element simualtions are carried out and the results show that a good reshaping effect can be achieved at a working frequency despite the reduced and the discreted material parameters as well as unneglectable dipersion and loss effects. And the frequency band can be broadened by choosing proper microstructures such that the resonance point is far from the distribution range of the structural factors.
Transformation of multi-edge-dislocations to screw-dislocations in optical field
Authors: Feng Bo  , Gan Xue-Tao  , Liu Sheng  , Zhao Jian-Lin  ,   Shaanxi Key Laboratory of Optical Information Technology, The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi’an 710072, China
Published: December 2020

Transformation of edge-dislocations to screw-dislocations in the optical field is experimentally and numerically demonstrated. A special multi-edge-dislocation structure is designed by arranging multiple edge-dislocations, which have the same phase-step value, periodically along the azimuthal orientation. Experimentally, in virtue of the computer-generated holography, a Gaussian beam is modulated by the multi-edge-dislocation, whose propagation dynamics is investigated as well. The results reveal that the multi-edge-dislocation can be converted into a screw-dislocation with the evolution of the Gaussian beam into a vortex-like beam. What is more, the sum phase change of the dislocations is conserved in this process. Then, the experimental results are verified by numerical simulations, and discussed in detail by analyzing the evolutions of the linear momentum density. Furthermore, the influence of the phase-step value of the edge-dislocation on the transformation is discussed, which illustrates the quantitative relation between the phase-step value and the topological charge of crew-dislocation.