bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate Rutherford backscattering spectrocsopy measurement of aluminium composition in AlxGa1-xN crystal film
Authors: Liu Yun-Chuan  , Zhou Yan-Ping  , Wang Xue-Rong  , Meng Xiang-Yan  , Duan Jian  , Zheng Hui-Bao  ,   Institute 53 of China’s Ordnance Industry Group, Jinan 250031, China
Published: December 2020

The AlxGa1-xN epitaxial film is grown on (0001)-oriented sapphire with a 20 nm thick aluminium nitride buffer layer by metal organic chemical vapor deposition. The thickness of AlxGa1-xN layer with high crystal quality is about 2 μrm determined by ultraviolet visible light transmittance spectrum analysis. The homogeneity of aluminium in AlxGa1-xN epitaxial film is tested through the energy Eg at the peak intensity in the deep ultraviolet photoluminescence spectrum. The epitaxial wafer with good homogeneity is used to determine aluminium composition by Rutherford backscattering spectroscopy (RBS). Six samples are measured by tow ion beam analysis laboratories, and the experimental data of RBS random spectrum are simulated by the software. The source of measurement uncertainty is analyzed including the sample homogeneity, pileup correction and counting statistics and so on. The research results show that when the alpha particle is used as incident ion, with 2000 keV energy and 165° scattering angle, the measurement uncertainty of RBS for the determination of aluminium composition (x=0.8) is 2.0% and the coverage factor k=2.
Spectroscopic properties and molecular constants of the ground and excited states of SF molecule
Authors: Zhu Zun-Lüe  , Lang Jian-Hua  , Qiao Hao  ,   College of Physics and Electronic Engineering, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The potential energy curves (PEC) for the ground state (X2∏) and three excited states (4∑-, 2∑-, 2Δ) of SF molecule are computed using the multireference configuration interaction method and the basis sets aug-cc-pV6Z where the Davidson correction is considered as an approximation to full CI. The separation parameters (Re, ωe, ωeχe, D0, De, Be and αe) are evaluated using the PEC of SF. The spectroscopic parameters are compared with those reported in the literature, and excellent agreement is found between them. With the PEC of SF, some vibrational states of SF are predicted when J=0 by numerically solving the radical Schrödinger equation of nuclear motion. For each vibrational state, the vibrational levels and inertial rotation constants are reported.
Infrared absorption spectrum of solid deuterium at near-triple point temperature
Authors: Liu Jiang-Ping  , Bi Peng  , Lei Hai-Le  , Li Jun  , Wei Jian-Jun  ,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;,   Research Centre of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The low mode energy of deuterium is calculated by quantum mechanics theory and deuterium zero-point vibration energy. The smooth, uniformity, euphotic solid deuterium film is obtained by home-made planar cryotarget system. The infrared absorption spectrum of solid deuterium film is studied by infrared spectroscopy system. The strong absorption peaks mostly result from the Q1(0)+S0(0), Q1(0)+S0(1), Q1(0)+S0(0)+S0(1) vibration, rotation modes. The experimental data are in good agreement with the analysis results.
Resonance enhanced multiphoton ionization spectra of HCl：analysis of F1Δ2 spectral perturbation
Authors: Long Jing-Ming  , Wang Hua-Sheng  ,   Science Institute, University of Iceland, Reykjavik 107, Iceland
Published: December 2020

Spectra of H+, 35Cl+, H35Cl+ and their isotopologues, due to resonance enhanced multiphoton ionization (REMPI) of HCl via the F1Δ2 (v’=1) Rydberg and V1∑+ (v’=13, 14) ion-pair states are recorded in a range of 84800-85700 cm-1. Perturbation effects indicate the resonance interaction between the F1Δ2 (v’=1) and V1∑+ (v’=14) states. An improved model for analyzing relative signal intensity of spectrum, based on state interaction and photofragmentation process, is used to analyze the F1Δ2 (v’=1) spectral data. Interaction strength (W’=0.6 cm-1) and a predissociation parameter (γ=0.025) are derived. Comparable interaction strength and unperturbed spectroscopic parameters are derived from the deperturbation analysis of line positions for the F1Δ2 (v’=1) and V1∑+ (v’=13, 14) spectra. The study indicates that the formation of the H+ and Cl+ ions via two-photon resonance excitation of F1Δ2 (v’=1) state is associated with the state interaction. An indication of the line-shift of F1Δ2 (v’=1) state spectrum due to Rydberg-to-Rydberg state interaction is also found. The nonzero γ value suggests that the predissociation of the F1Δ2 state is important.
A theoretical study on non-first-order effects of double differential cross sections
Authors: Xue Si-Min  ,   School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China
Published: December 2020

The double differential cross sections for electron impact ionization of hydrogen at different incident energies are calculated by use of the Brauner-Briggs-Klar (BBK) model and first order born approximation model. The results are compared with experimental data and other theoretical results. The non-first-order effects of the BBK model are analyzed and discussed in detail.
Application of group theory in the problem of electromagnetic scattering of symmetry structures
Authors: Xu Chang-Wei  , Zhu Feng  , Liu Li-Na  , Niu Da-Peng  ,   Department of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

When solving electromagnetic scattering problem with T-matrix method, if the scattering obstacles have point-group symmetry, i.e. remaining unchanged under the group transformation, we can obtain the relationship between geometric symmetry and symmetry of elements in T matrix by the usage of group theory. In this way we can foresee the exact values of some matrix elements, as well as relations between elements, which would save numerous running time in numerical calculation.
Investigation on the reconstruction of objects buried in layered media based on the equivalent current source
Authors: Zhang Peng  , Zhang Xiao-Juan  ,   Key Laboratory of Electromagnetic Radiation and Sensing Technology of Chinese Academy of Sciences, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China;,   University of Chinese Academy of Science, Beijing 100190, China
Published: December 2020

In this paper, a new algorithm based on the equivalent current source is proposed to reconstruct the objects buried in layered media. In this method the radiating current source from the scattering data is first reconstructed and the reconstruction of equivalent current source and objects are then achieved efficiently by solving an optimization problem in a lower dimensional linear space using the conjugate gradient method. The effects of the frequency of incident wave, sampling interval, length of measurement line level of noise, and the estimation of background on the reconstructed results are studied and analyzed in detail. Numerical results show that the proposed method has a high ability to reconstruct the objects buried in layered media. Therefore, the method can be used to solve the problems in the areas of through-the-wall imaging and geophysical exploration and so on.
Diffraction barrier breakthrough in coherent anti-Stokes Raman scattering microscopy and detection limitanalysis
Authors: Liu Wei  , Chen Dan-Ni  , Liu Shuang-Long  , Niu Han-Ben  ,   Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China;,   College of Precision Instrument and Opt-Electronics Engineering, Tianjin University, Tianjin 300072, China
Published: December 2020

We provide an approach to breaking the diffraction limit in coherent anti-Stokes Raman scattering (CARS) microscopy and report a theoretical analysis of detection limit (DL) forit. The additional probe beam, whose profile is doughnut shaped and wavelength is different from the size of Gaussian probe beam, interacts with the coherent phonons at the rim of the diffraction-limited spot to increase theresolution by re-engineering the point spreadfunction of the system. The signal strength reduces with the size of focal volume decreasing, besides, when CARS is used in biology, the molecules of interest are usually in low concentration, which makes the signal detection more difficult. Accordingly, a remaining crucial problem is whether the reduced signal generated in the suppressed focal volume can be detected from the noise background and the analysis of DL, so it is an important precise in implementation of CARS nanoscopy. We describe T-CARS process with full quantum theory and estimate the extreme power density levels of the pump and Stokes beams determined by saturation behavior of coherent phonons. When the pump and Stokes intensities reach such extreme values and total intensity of the excitation beams arrives at a maximum tolerable by most biological samples in acertain suppressed focal volume, the DL of T-CARS nanoscopy correspondingly varies with the exposure time. For an attainable spatial resolution of ～40 nm in three dimension and areasonable exposure time of 20 ms, the DL in the suppressed focal volume is approximately ～103. The signal can be well detected from the noise fluctuation only if the number of molecules of interest exceeds this limit.
Joint spectral and depth domain spectral domain phase microscopy
Authors: Yan Yang-Zhi  , Ding Zhi-Hua  , Wang Ling  , Shen Yi  ,   State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China;,   Institute for Biomedical Engineering and Instrumentation, Hangzhou Dianzi University, Hangzhou 310018, China
Published: December 2020

We present a joint spectral and depth domain spectral domain phase microscopy for high-sensitive and high-dynamic-range quantitative phase imaging, where phase information retrieved in spectral domain is used to overcome the limitation of 2π ambiguity and phase information in depth domain is used to achieve a high phase sensitivity. By theoretical derivation and simulation, the sensitivity advantage of phase information in depth domain over phase information in spectral domain is investigated. The theoretical derivation of joint spectral and depth domain spectral domain phase microscopy is presented in detail. The performance of the proposed joint spectral and depth domain spectral domain phase microscopy is illustrated by phase imaging of a coverslip and a resolution target.
Influence of pump chirp on the purity of an all fiber source of correlated photon pairs
Authors: Wang Kun  , Cui Liang  , Zhang Xiu-Ting  , Li Xiao-Ying  ,   Key Laboratory of Opto-Electronic Information Technology of Ministry of Education, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
Published: December 2020

The all fiber sources of photon pairs in the 1550 nm telecom band have the advantages of low cost and compatibility with the fiber network. Further improving the purity will improve the practicality of the quantum light sources. For the pulsed pump field propagating through the optical fiber, a certain amount of chirp will be inevitably induced due to the effects of chromatic of dispersion and Kerr nonlinearity, but its influence on the purity has not been studied yet. In this paper, using photon pairs produced by the spontaneous four wave mixing in dispersion shifted fiber, we study the influence of pump chirp on the purity of photon pairs by varying the chirp of the pulsed pump. For the pump with a given bandwidth, our results demonstrate that the purity of photon pairs having a certain production rate, decreases with the increase of the absolute quantity of pump chirp. Therefore, the purity of the photon pairs with relatively small detuning can be improved by using the transform limited pump pulses due to the suppressed Raman scattering.
Generation of femtosecond pulsed quadrature phase squeezed light
Authors: Liu Hong-Yu  , Chen Li  , Liu Ling  , Ming Ying  , Liu Kui  , Zhang Jun-Xiang  , Gao Jiang-Rui  ,   State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China;,   Department of Physics, Yanbian University, Yanji 133002, China
Published: December 2020

We demonstrate experimentally the short pulse amplitude squeezed light from a singly resonant synchronously pumped optical parametric oscillator (SPOPO). The SPOPO operates in the frequency degenerate case and below threshold, with using a periodically poled potassium titanyl phosphate crystal. The pump laser is the second harmonic of a ultrashort mode-locked femtosecond pulse at 850 nm. The reduction of quantum noise of 2.58 dB is obtained experimentally. The squeezing extent is deduced to be 4.48 dB.
Lasing without inversion with considering spontaneously generated coherence
Authors: Zhang Bing  , Liu Zhi-Xue  , Xu Wan-Chao  ,   College of Physics and Electronic Engineering, Mudanjiang Normal University, Mudanjiang 157012, China;,   Key Laboratory of Heilongjiang Super-Hard Materials, Mudanjiang 157012, China
Published: December 2020

We provide a four-level double-V type atomic system driven by two week probe fields and two strong coupling laser beams. In the condition of resonant four-wave mixing, the two probe fields can be amplified without population inversion. Due to the fact that the two excited states are close- lying upper levels of hyperfine structure, the spontaneously generated coherence (SGC) effect must be considered. Interestingly, the amplitude of gain is sufficiently enhanced with the same parameters as those in the case without considering SGC. In addition, we find that the probe gain is sensitive to the phase of two laser fields which interact with the same lower level. To be more specific, the amplitude of gain is modulated by the phase periodically but restricted by θ (the angle between two induced dipole moments). At the same time, we also analyze the influence of the coherence pumping (strong coupling fields) detuning.
Dual-channel chaos synchronization and communication based on a vertical-cavity surface emitting laser with double optical feedback
Authors: Deng Wei  , Xia Guang-Qiong  , Wu Zheng-Mao  ,   School of Physical Science and Technology, Southwest University, Chongqing 400715, China
Published: December 2020

Using two orthogonal polarization mode outputs from a vertical-cavity surface emitting lasers (VCSEL) with double optical feedback as two chaotic carriers, a dual-channel chaos secure communication system is established, and the synchronization and communication performances of such a system are numerically investigated. The results show that under suitable operated condition, the time-delay signatures of two chaotic carriers originating from two linear polarization modes in the T-VCSLE with double optical feedback can be suppressed efficiently. Under the strong injection locking case, high-quality chaos synchronization between two corresponding modes of T-VCSEL and R-VCSEL can be realized by polarization-preserved optical injection from T-VCSEL to R-VCSEL. Moreover, the tolerance of the synchronization quality on the frequency detuning between T-VCSEL and R-VCSEL is enhanced with the increase of the injection strength. Adopting additive chaos modulation encryption scheme, two pieces of 500 Mbit/s encoded message can be hidden efficiently in the two chaotic carriers in the propagation process and can be successfully extracted at the receiver. Although Q factor decreases with the increase of message transmission rate, the values of Q factor for two channels are still larger than 6 for 6 Gbit/s message.
Scintillation statistics of a retro-reflected wave from space
Authors: Wang Li-Guo  , Wu Zhen-Sen  , Wang Ming-Jun  ,   School of Science, Xidian University, Xi’an 710071, China;,   School of Physics and Electronic Engineering, Xianyang Normal College, Xianyang 712000, China
Published: December 2020

Rytov theory combined with the ABCD ray matrix is used to analyzes the statistical property of a reflected wave from a retro-reflector caused by atmospheric turbulence. The covariance function and the scintillation index of the receiving field caused by the combined effect of the turbulence and the random shaking of the reflector array are deduced on the basis of the mutual statistical independence of the two kinds of effects. The aperture factor and the scintillation of a receiving aperture with a finite size are calculated, and those of the retro-reflector and the array are compared to prove that the array does not change distribution of the intensity fluctuation but amplifies the fluctuation by a factor of 2.
Control of the fluctuation in the uniform granular flow by a random force field
Authors: Su Tao  , Feng Yao-Dong  , Zhao Hong-Wu  , Huang De-Cai  , Sun Gang  ,   Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

A normal distribution random force field is introduced into the study of granular flow, and its effect is observed by computer simulations. The results show that the random force almost does not cause changes in average density and velocity in a uniform granular flow, and affects little the fluctuation of the density. The main effect of the random force field is that it increases the fluctuation of the granular velocity and maintains the granular flow at a certain dispersed kinetic energy by competing with the dissipation of the granular system. It is also shown that the dispersed kinetic energy obtained by the random force field is not equally distributed in each degree of freedom, and that the equipartition of energy is difficult to realize in granular system because of its dissipation property.
Experimental study on the local equation of state for vibrated granular gases
Authors: Chen Yan-Pei  , Pierre Evesque  , Hou Mei-Ying  ,   Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condense Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   Laboratory MSSMat, Ecole Centrale Paris, UMR 8579 CNRS, Chatenay-Malabry Cedex 92295, France
Published: December 2020

We experimentally measure the local equation of state for two-dimensional horizontal fluidize granular gases confined in a rectangle box. Local equation of state can be seen as a local constitutive equation of temperature, pressure and the number density. Except the kinetic parts, the collision parts of the stress tensor are included. The diagonal components of the stress tensor are almost constant, which is consistent with the results from the simulation and hydrodynamic theory. Furthermore, the spacial profiles of the temperature and the number density are shown to be consistent with the experimental results of micro-gravity. Finally the local equations of state for different area fractions are found to have great discrepancies with the theoretical predictions no matter how the low or dense the density is.
Effects of grain size on the dynamic tensile damage of ductile polycrystalline metall
Authors: Zhang Feng-Guo  , Zhou Hong-Qiang  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
Published: December 2020

In the paper, we propose a new nucleation rate function, which combines grain size, and models for nucleation and growth of voids in a ductile polycrystalline metal. The proposed model is used to analyse the effects of grain size on the dynamic tensile damage of high purity Cu samples with different grain sizes. Numerical results show that pull-back minima and void number decrease with grain size increasing, slope after pull-back and average void diameter increase with grain size increasing. The computed results are in qualitative agreement with experimental results.
Effect of laser-induced zinc micro-spheres on enhanced absorption of subsequent pulse laser
Authors: Chen Ming  , Li Shuang  , Cui Qing-Qiang  , Liu Xiang-Dong  ,   School of Physics, Shandong University, Jinan 250100, China;,   School of Computer, Shandong Xiehe University, Jinan 250100, China;,   State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
Published: December 2020

Numerous football-shaped Zinc micro-spheres on inner surface of the crater are produced by pulsed laser ablation of Zn metals in vacuum condition (～2 Pa). Pulsed laser induced plasma emission spectrum is measured to reveal the effects of macro- and micro-structures on subsequent pulse laser ablation. The intensity of spectral line at 334.5 nm originating from Zn atoms by subsequent laser ablation of the ablated spot is 10.3% higher than that created over a smooth surface. The intensity of the same spectral line produced over a ablated spot with a great number of micro-spheres is 1.343 times higher than that produced by the plasma generated over the ablated spot. The Zn micro-sphere completely covered with nano-scaled regular pentagonal and hexagonal facets can lead to an enhanced absorption of the following laser energy. The total number of Zn micro-spheres increases as the number of laser shots increses, which can result in hotter and dense plasma by subsequent laser ablation. The proposed results are of importance for developing the laser micro-drilling technique.
Investigation on the characteristics of dielectric barrier discharge with fairly large volume generated in air at atmospheric pressure
Authors: Li Xue-Chen  , Chang Yuan-Yuan  , Liu Run-Fu  , Zhao Huan-Huan  , Di Cong  ,   Key Laboratory of Photo-Electronics Information Materials of Hebei Province, College of Physics Science and Technology, Hebei University, Baoding 071002, China
Published: December 2020

By using a tri-electrode dielectric barrier discharge device, a uniform discharge with fairly large volume is realized in the main discharge region in atmospheric pressure air. The characteristics of the main discharge are investigated by optical and electrical methods. Results show that the main discharge includes two discharge modes with changing the input power of the source, which are a plasma plume discharge and a plasma column discharge. The inception voltage decreases with the increase of the peak value of the applied voltage for plume discharge. It can be deduced that the pre-ionization of air in the main discharge region is important for the main discharge, which results from the UV emitted from the coaxial dielectric barrier discharge. Spatially resolved measurements are conducted on the plasma plume and the plasma column with photomultiplier tubes. It is found that the plasma plume behaves like a plasma bullet that corresponds to a fast moving layer of light emission zone. Comparatively, the discharges at different positions of the plasma column almost volley, which means that the plasma column is of continuous discharge. Through analyzing the optical spectrum emitted from the main discharge, the vibrational temperature and rotational temperature are calculated. Results indicate that both the vibrational temperature and the rotational temperature decrease with the increase of peak value of the applied voltage. These results are of significance for the industrial applications of dielectric barrier discharge.
Effects of helium and deuterium on irradiation damage in pure iron
Authors: Jiang Shao-Ning  , Wan Fa-Rong  , Long Yi  , Liu Chuan-Xin  , Zhan Qian  , Ohnuki Somei  ,   School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;,   Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
Published: December 2020

Productions of transmute elements (hydrogen and helium) have great influences on the resistance to irradiation damage in structural materials for fusion reactor. The evolution of irradiation damage in bcc iron is investigated with ion implantation and electron irradiation. Pure iron implanted by He+ or D+ ions at room temperature are aged at 500℃ for 1 h, then irradiated by electrons under high voltage electron microscope. The results show that interstitial loops (i-loop) and vacancy loops (v-loop) are formed in He+-implanted iron and D+-implanted iron respectively. Under electron irradiation, due to the absorption of interstitials atom, i-loop grows up while v-loop shrinks. According to the rate of variation of dislocation loop, v-loop absorbs more interstitial atoms, i.e., the dislocation bias of D+-implanted iron is larger than that of He+-implanted iron, which means that the v-loop has the more contributions to irradiation swelling than i-loop. The causes of the different natures of dislocation loops formed in D+-implanted iron and He+-implanted iron are analyzed by the structures of He-V and D-V complexes.
Effects of intrachain disorder on polaron transport in conjugated polymer
Authors: Li Dong-Mei  , Yuan Xiao-Juan  , Zhou Jia-Qiang  ,   State Key Laboratory of Crystal Materials, School of Physics, Shandong University, Jinan 250100, China;,   Department of Physics, Qilu Normal University, Zhangqiu 250200, China
Published: December 2020

Polaron transport process in conjugated polymer with intrachain disorder is simulated using a nonadiabatic evolution method. The simulations are performed within the framework of an extended version of the Su-Schrieffer-Heeger model modified to include intrachin disorder and an external electric field. It is found that the polaron transport mechanism is determined by both the electric field and the intrachain disorder. The effects of intrachin disorder are negative in most cases, but with the increase of the electric field, the influence of intrachin disorder on polaron transport decreases.
Optical Tamm state theory study on asymmetric DBR-metal-DBR structure
Authors: Jiang Yao  , Zhang Wei-Li  , Zhu Ye-Yu  ,   Key Laboratory of Optical Fiber Sensing and Communications, Ministry of Education, School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
Published: December 2020

As a special metal surface state, optical Tamm state (OTS) has been widely used in designing the new generation of optical devices for its unique advantages in light control and operation. Based on distribute Bragg reflector (DBR)-metal-DBR (DMD)structure, asymmetric mechanism is introduced by mismatching central frequencies of the two DBRs to design and control the generation of OTS. Through the analysis of reflection spectrum and the electric field distribution characteristics, the interaction and variation rules of OTS on each side of metal are revealed. The results indicate that the DMD structure can support the presence of two OTSs with different intrinsic wavelengths. Besides, the mismatch will affect the strengths and intrinsic wavelengths of the two OTSs, i.e., the upper and lower branches of OTS appear with the variation of . In addition, polarization state and injection angle of incident light have a considerable influence on the strength and intrinsic wavelength of OTS.
Flat-roof of dynamic equilibrium phenomenon in static negative biase temperature instability effect on power metal-oxide-semiconductor field-effect transistor
Authors: Zhang Yue  , Zhuo Qing-Qing  , Liu Hong-Xia  , Ma Xiao-Hua  , Hao Yue  ,   School of Microelectronics, Xidian University, Xi’an 710071, China;,   School of Technical Physics, Xidian University, Xi’an 710071, China;,   Key Laboratory of Wide Bandgap Semiconductor Materials and Devices of Ministry of Education, Xi’an 710071, China
Published: December 2020

The effect of static negative bias temperature instability stress on p-channel power metal-oxide-semiconductor field-effect transistor (MOSFET) is investigated by experiment and simulation. The time evolution of the negative bias temperature instability degradation presents the trend which follows the reaction-diffusion (R-D) theory on the exaggerated time scale. A flat-roof section is observed under the varying stress condition, which can be considered as the dynamic equilibrium phase through the simulation verification based on the R-D model. The analysis of the simulated results also provides the explanation for the difference in the time duration of the dynamic equilibrium phase under the condition of varying stress voltage.
Design and study of the dual-band frequency-selective surface operation at Ku/Ka-band
Authors: Wang Xiu-Zhi  , Gao Jin-Song  , Xu Nian-Xi  ,   Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

In order to make the dual-band frequency-selective surface (FSS) used in the engineering conditions of thick substrate, wide band spacing and large incident angle, an FSS structure with dual-band at Ku-band and Ka-band is presented. The stable filtering condition of the FSS is analyzed by using the grating lobe diagram, and the transmission of the FSS with combination or fractal elements is calculated using the vector modal matching method. The design method of the dual-band FSS with thick substrate is obtained by analyzing the resonance mode of the element and the transmission of the FSS. By using those methods, an FSS with combination elements of the square and Y loops is designed. The simulated and tested results show that the dual-bands of the structure at Ku-band and Ka-band are stable and the transmissions of the two pass-bands are larger than 75% when the incident angle is varied from normal to 45. This paper provides some theoretical and experimental references for the design of the dual-band FSS with thick substrate, wide band spacing and large incident angle.
Magnetic properties and magnetocaloric effect in Mn42Al50-xFe8+x alloys
Authors: Wang Fang  , Yuan Feng-Ying  , Wang Jin-Zhi  ,   Ningbo University of Technology, Ningbo 315211, China;,   Tianjin University of Science and Technology, Tianjin 300222, China
Published: December 2020

The structure, magnetism and magnetocaloric effect in Mn42Al50-xFe8+x are studied in this paper. The Curie temperature (TC) is tunable in a wide temperature range around the ambient temperature by varying the Fe and Al concentration. The values of TC are 270 K, 341 K and 370 K, respectively corresponding to the values of x of 8, 10 and 12. The magnetization has a sharp drop around the respective phase transition temperature and no obvious thermal or magnetic hysteresis is found, suggesting that a typical reversible second order phase transition occurs. The maxima of the magnetic entropy change (Sm) under an applied field change of 0-5 T are 2.48 (Mn42Al42Fe16), 2.52 (Mn42Al40Fe18) and 2.40 Jkg-1K-1 (Mn42Al38Fe20), which are almost independent of composition. The simple and easy preparation process, the good corrosion resistance and ductility, the reversible second order phase transition, and the low cost of raw material make them attractive candidate for the magnetic refrigerant, although their values of Sm are not very large compared those that of the rare earth based compounds.
First-principles study of Ag-N dual-doped p-type ZnO
Authors: Li Wan-Jun  , Fang Liang  , Qin Guo-Ping  , Ruan Hai-Bo  , Kong Chun-Yang  , Zheng Ji  , Bian Ping  , Xu Qing  , Wu Fang  ,   College of Physics, Chongqing University, Chongqing 401331, China;,   College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331, China;,   Key Laboratory of Optoelectronic Functional Materials of Chongqing, Chongqing 401331, China;,   Research Center for Materials Interdisciplinary Sciences, Chongqing University of Arts and Sciences, Chongqing 402168, China
Published: December 2020

The formation energies and ionization energies of Ag-N dual-doped ZnO and interstitial N and H monodoped ZnO:(Ag,N) are investigated from the firstprinciples pseudo-potential approach based on density functional theory. It is found that AgZn-NO accepter pair has lower formation energy and ionization energy than Ag-N related to acceptor clusters, which demonstrates that the p-type conductivity of Ag-N dual-doped ZnO system is mainly attributed to the formation of the accepter pairs. Moreover, when ZnO:(Ag,N) system has additional N atoms in some interstitial sites of ZnO crystal, interstitial N atom and AgZn-NO accepter pair prefer to bind together to form AgZn-(N2)O donor complex which lowers doping efficiency, which is not conducive to p-type conductivity. For H doping in the ZnO:(Ag,N) system, the interstitial H atoms also prefer to bind to the AgZn-NO accepter pair, forming acceptor-donor-acceptor (AgZn-H#em/em#-NO) triplet, which not only enhances the incorporation of acceptors (AgZn-NO) but also gives rise to a shallower acceptor level in the band gap in p-type ZnO crystal. Thus, it is suggested that H-assisted Ag-N codoping is an effective method of p-type doping in ZnO.
Analysis on steady plasma process of high-rate microcrystalline silicon by optical emission spectroscopy
Authors: Fang Jia  , Li Shuang-Liang  , Xu Sheng-Zhi  , Wei Chang-Chun  , Zhao Ying  , Zhang Xiao-Dan  ,   Key Laboratory of Photo-Electronic Thin Film Devices and Technique of Tianjin, Key Laboratory of Photo-Electronic Information Science and Technology of Ministry of Education, Institute of Photo-Electronic Thin Film Devices and Technique, Tianjin 300071, China
Published: December 2020

The ratio of I(Hα*)/I(SiH*), obtained from the real time optical emission spectroscopy (OES) measurement in the high-rate microcrystalline silicon deposition process, as a function of time is used to analyze the cause of increasing crystallinity along the growth direction. Hydrogen dilution gradient method which means silane concentration gradient and hydrogen flow gradient method is adopted to improve vertical structure uniformity of the material. High-quality microcrystalline material around 53%-62% of Xc can be prepared through silane concentration gradient compared with 55%-75% of Xc prepared in the traditional method. In the silane depleted cases, by increasing the hydrogen flow the longitudinal uniformity of the material can be effectively improved. The vertical crystallinity around 53%-60% can be obtained. This is mainly due to the increase of the hydrogen flow that makes the collision probability increased, as a result, electron temperature of plasma reduced. Thus, the decomposition of hydrogen decreases and the reaction of hydrogen annihilation is suppressed. At the same time, the influence of back diffusion of SiH4 is suppressed. The gradually increasing trend of the ratio of I(Hα*)/I(SiH*) is controlled during the deposition of microcrystalline silicon film.
Output short-circuit spark discharging energy and output intrinsic safety criterion of Buck converters
Authors: Liu Shu-Lin  , Cui Qiang  , Li Yong  ,   School of Electrical and Control Engineering, Xi’an University of Science and Technology, Xi’an 710054, China
Published: December 2020

To obtain the output intrinsic safety criterion of Buck converters, the experimental research on its output-short circuit discharge characteristics is conducted by using the safety spark test apparatus. It is found that its spark discharge process can be divided into four stages, i.e., the dielectric-breakdown, spark-generation, spark-keeping and spark-extinguishment. According to the obtained spark discharge characteristics, the output short-circuit spark discharging energy (OSSDE) is deeply analyzed. It is indicated that the OSSDE of the Buck converter with a given inductance is a concave function of load resistance RL when RL is less than the critical resistance RLC corresponding to this inductance, while that is a convex function of RL in the case of RL > RLC. Considering the actual parameter range of the Buck converter, it is further pointed out that when RL RLC, the OSSDE increases with the increase of RL and reaches its maximum in the case of RL=RLC; when RL > RLC, the OSSDE first increases and then decreases with the increase of RL and reaches its maximum in the case of RL, DCM. The most dangerous operating conditions of the converter in whole dynamic range are obtained, i.e., the converter operates in DCM when the input voltage is the highest and RL=RL, DCM. Meanwhile, the maximum OSSDE is achieved. According to the energy equivalence, an output intrinsic safety criterion for Buck converter is proposed by modeling the output short-circuit discharging behaviour as a simple capacitive circuit. The theoretical analysis and proposed criterion are verified by the simulation and experimental results.
Advisor-advisee relationship identification based on maximum entropy model
Authors: Li Yong-Jun  , Liu Zun  , Yu Hui  ,   School of Computer, Northwestern Polytechnical University, Xi’an 710072, China
Published: December 2020

Research collaboration network has become an essential part in our academic activities. We can keep or develop collaboration relationships with other researchers or share research results with them within the research collaboration network. It is well generally accepted that different relationships have essentially different influences on the collaboration of researchers. Such a scenario also happens in our daily life. The advisor-advisee relationship plays an important role in the research collaboration network, so identification of advisor-advisee relationship can benefit the collaboration of researchers. In this paper, we aim to conduct a systematic investigation of the problem of indentifying the social relationship types from publication networks, and try to propose an easily computed and effective solution to this problem. Based on the common knowledge that graduate student always co-authors his papers with his advisor and not vice versa, our study starts with an analysis on publication network, and retrieves these features that can represent the advisor-advisee relationship. According to these features, an advisor-advisee relationship identification algorithm based on maximum entropy model with feature selection is proposed in this paper. We employ the DBLP dataset to test the proposed algorithm. The results show that 1) the mean of deviation of estimated end year to graduation year is 1.39; 2) the accuracy of advisor-advisee relationship identification results is more than 95%, and it is better than those of other algorithms obviously. Finally, the proposed algorithm can be extended to the relationship identification in online social network.
The measurement of complex network based on motif
Authors: Han Hua  , Liu Wan-Lu  , Wu Ling-Yan  ,   School of Science, Wuhan University of Technology, Wuhan 430070, China
Published: December 2020

According to the existence of motif in complex network topology structure, the motif-based node degree and edge degree are proposed to measure the importance of node and edge in the network on the basis of the traditional node degree and edge clustering coefficient. The Rand-ESU algorithm is used for motif detection of eight different scale networks, and the result demonstrates the existence of motif. The Rand-ESU algorithm is also used for analyzing the motif structures and characteristics in Karate network and Dolphin network. The Pearson correlation coefficient is used to measure the correlations of motif-based node degree and traditional node degree, motif-based edge degree and edge clustering coefficient. The results of simulation analysis show that the correlations are related to the motif species. The definitions of motif-based node degree and edge degree are the improvement and development of original definitions, and they comprehensively depict the importance of node and edge in the network.
Perturbation method of travelling wave solution for (2+1) dimensional disturbed time delay breaking solitary wave equation
Authors: Ouyang Cheng  , Shi Lan-Fang  , Lin Wan-Tao  , Mo Jia-Qi  ,   Faculty of Science, Huzhou Teacher College, Huzhou 313000, China;,   College of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing 210044, China;,   State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamic, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;,   Department of Mathemtics, Anhui Normal University, Wuhu 241003, China
Published: December 2020

A class of (2+1) dimentional disturbed time-delay breaking solitary wave equation is studied. Firstly, the corresponding non-delay breaking equation is considered. The exact solitary wave solution is obtained by using the mapping method with undetermined coefficients. Then, the travelling asymptotic solution of disturbed breaking solitary wave equation is found by using the homotopic mapping and perturbed approximate method.
Wigner-Yanse skew information of the system with the electromagnetically induced transparency
Authors: Fu Jing  , Liu Wan-Fang  , Zhao Yu-Jie  ,   The City College of Jilin Architectural and Civil Engineering Insitute, Changchun 130111, China;,   School of & Electric Engineering, Anqing Teachers College, Anqing 246011, China
Published: December 2020

The quantum-information theoretic notation of the Winger-Yanse skew information has been used to analyze the process of information transfer between probe fields and atomic ensemble in the electromagnetically induced transparency. It is well known that the skew information is a well-defined measure that quantifies the amount of the information a quantum state contains. We have calculated the dynamical skew information of the probe fields and the atomic ensemble, and found that the information for the individual atom is dependent of the numbers of the particles and the photons, as well as the state of the probe field. For a sufficiently weak coherent driving field, the dark-state polaritons is a purely atomic state with no photons in the composite system, and the information of the individual atom reaches the maximum value. However, the information of the probe field is not completely transferred into the atomic ensemble.
Three-party quantum key agreement with Bell states
Authors: Yin Xun-Ru  , Ma Wen-Ping  , Shen Dong-Su  , Wang Li-Li  ,   State Key Laboratory of Integrated Service Networks, Xidian University, Xi’an 710071, China;,   School of Mathematics and Statistics, Taishan University, Tai’an 271000, China
Published: December 2020

A three-party quantum key agreement protocol based on EPR pairs is proposed, in which the three participants have equal status in the protocol and each participant is capable of contributing to the shared secret key in the same degree. In addition, any one or two parties cannot predetermine the value of shared key alone. The security analysis shows that our protocol can resist the outside attack and the dishonest participants attack.
A modified chaotic ant swarm optimization algorithm
Authors: Liu Le-Zhu  , Zhang Ji-Qian  , Xu Gui-Xia  , Liang Li-Si  , Huang Shou-Fang  ,   College of Physics and Electronic Information, Anhui Normal University, Wuhu 241000, China
Published: December 2020

This paper proposed a modified chaotic ant swarm optimization under an effective termination condition. Numerical calculation verifies the validity of the modified algorithm. Simulation of the algorithm indicates that the algorithm can have a high-accuracy optimal solution. Through multiple chaotic searches, the modified algorithm gradually approaches the optimal solution which can be used to solve complex continuous domain optimization problem.
Sampled-data synchronization control of chaotic systems based on min-max approach
Authors: Ren Tao  , Zhu Zhi-Liang  , Yu Hai  , Wang Meng  ,   Software College, Northeastern University, Shenyang 110011, China;,   School of Information Science and Engineering, Northeastern University, Shenyang 110011, China
Published: December 2020

For the chaotic systems with disturbance, a sampled-data controller is designed to achieve chaotic synchronization. Firstly, to handle the discontinuity introduced by the sampling activities, the input-delay approach is introduced to transform the discontinuous chaotic systems into continuous ones. Secondly, the worst possible case of performance is considered according to min-max robust strategy. Then the sufficient conditions for global asymptotic synchronization of such chaotic systems are derived and expressed in terms of linear matrix inequality (LMI). The proposed algorithm can achieve synchronization of the sampled-data chaotic systems for all admissible disturbances at the pre-computed set of disturbance realizations. The effectiveness is finally illustrated via numerical simulations of chaotic Chuas circuit, and the simulation results show that the proposed algorithm is suitable for secure communication.
Chaos synchronization of FitzHugh-Nagumo neurons via backstepping and adaptive dynamical sliding mode control
Authors: Yu Hai-Tao  , Wang Jiang  ,   School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072, China
Published: December 2020

In this paper, backstepping and adaptive dynamical sliding mode control is used to achieve chaos synchronization of coupled FitzHugh-Nagumo (FHN) neurons. The proposed controller consists of a combination of dynamical sliding mode control and adaptive backstepping technique. Based on a new switching function, the combined algorithm yields a design of dynamical sliding mode control law, which can realize chaos synchronization of coupled FHN neurons with uncertain parameters. It is shown that the proposed approach can effectively remove the chattering characteristic of the system, so that the intrinsic dynamics of neurons can avoid to be destroyed. Furthermore, it has rapid control performance. The simulation results have demonstrated the effectiveness of the control scheme.
Shock pressure in femtosecond laser ablation of solid target
Authors: Wang Wen-Ting  , Zhang Nan  , Wang Ming-Wei  , He Yuan-Hang  , Yang Jian-Jun  , Zhu Xiao-Nong  ,   Institute of Modern Optics, Key Laboratory of Optical Information Science & Technology, Nankai University, Tianjin 300071, China;,   National Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

The concepts of shock pressure and shock temperature in the interaction of femtosecond laser pulse and solid target are defined. Then the relationship between the shock pressure and other physical parameters in the process of femtosecond laser ablation of aluminum, copper, and silicon targets are discussed. Absolute values of shock pressure are calculated by means of the time-resolved pump detection shadow-graph. Result of this investigation plays an important role in the secure femtosecond laser processing of energetic materials and the femtosecond laser propulsion technology.
Analysis of the dispersion and interaction impedance for a coupled cavity slow wave structure with double in-line slots in TWT
Authors: He Fang-Ming  , Luo Ji-Run  , Zhu Min  , Guo Wei  ,   Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

An analytical model is presented in this paper for a coupled cavity slow-wave structure (CCSWS) with double in-line slots, also known as the “Chodorow” structure. Under matching boundary conditions in conjunction with Green’s function techniques and moment method (MOM), the formulae for discussing the high frequency characteristics of the SWS, including dispersion and interaction impedance, are given. The frequency characteristics for an X band Chodorow structure are calculated using these formulae, Ansoft HFSS code and equivalent circuit model. Results show that the dispersion and interaction impedance obtained with the formulae are in good agreement with those calculated by Ansoft HFSS code, while its calculation rate is more rapid than that with the code, and its calculation precision is higher than that with equivalent circuit method, which is helpful for the engineering design.