bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and electromagnetic wave absorption of flower-like ZnO-CoFe2 O4 nanotube bundles composites
Authors: Fu Wu-You  , Cao Jing  , Li Yi-Xing  , Yang Hai-Bin  ,   State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China
Published: December 2020

Flower-like ZnO-CoFe2O4 nanotube bundle composites are prepared via two-step crystal growth process in water solution at 90 ℃, the wall thicknesses of the ZnO nanotubes are all about 60 nm, inner diameters of the tubes are all about 350 nm, ZnO nanotubes have been coated with CoFe2O4 nanoparticles, and the sizes of CoFe2O4 nanoparticles are below 40 nm. The thickness of CoFe2O4 coating layer increases with the increase of the content of CoFe2O4 in ZnO-CoFe2O4 composites. By using Flower-like ZnO,flower-like ZnO-CoFe2O4 nanotube bundles and CoFe2O4 nanoparticles as absorbents, and phenolic resin as the binder, their electromagnetic wave absorption properties are investigated, and the results show that the microwave wave absorbing performance is evidently improved compared with that of ZnO nanotube bundles and CoFe2O4 particles. When the content of ZnO is 60%, the maximum reflection loss is 28.3 dB.
Magnetoelectric coupling in NiFe2 O4-BiFeO3 composite films
Authors: Gu Jian-Jun  , Liu Li-Hu  , Qi Yun-Kai  , Xu Qin  , Zhang Hui-Min  , Sun Hui-Yuan  ,   (1)College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang 050016, China; Department of Physics, Hebei Normal University for Nationalities, Chengde 067000, China; (2)College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang 050016, China; Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050016, China
Published: December 2020

Multiferroic xNFO-(1-x)BFO (x =0.00 0.10, 0.15, 0.20, 0.25) composite films are prepared through self-assembling growth on Au/Ti/SiO2/Si substrates by chemical solution deposition (CSD). X-ray diffraction analysis shows that the perovskite BiFeO3 and the spinel structured NiFe2O4 phases are formed and separated. The leakage current density (J) in the film decreases and the remnant polarizations (M r) increases with the introduction of NFO. The value of J in 0.25NFO—0.75BFO film is found to be nearly two orders of magnitude lower than that in the BFO film, and the M r and the saturation magnetization ( M s) reach maxima, i.e. 2.3μC/cm2 and 70.2 kA·m-1, respectively. Therefore, from the calculation for magnetic moment of NFO we can conjecture that magnetoelectric coupling exists in the composite films.
Preparation and long-afterglow luminescence research of Sr0.6Ba0.2Ca0.2Al2O4 ∶Eu, Dy
Authors: Li Da  , Zhang Jun  , Zou Chang-Wei  , Shao Le-Xi  , Wang Yin-Hai  , Hu Yi-Hua  , Xie Wei  ,   Development Center for New Materials Engineering and Technology in Univesities of Guangdong Province, Zhanjiang 524048, China;,   School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China;,   School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China; Development Center for New Materials Engineering and Technology in Univesities of Guangdong Province, Zhanjiang 524048, China; Research Center o
Published: December 2020

The Ca and Ba co-doped long afterglow phosphors Sr0.6Ba0.2Ca0.2Al2O4 ∶Eu2+0.01, Dy3+0.02 and only Ba doped phosphors Sr0.6Ba0.4Al2O4 ∶Eu2+0.01, Dy3+0.02 are synthesized by a high temperature solid-state reaction method. The phase structures of the phosphors are characterized by x-ray diffraction, showing that the crystal structures of samples are hexagonal. Photoluminescence spectra show that Eu2+ ion acts as the only luminescence center in sample,and Sr0.6Ba0.2Ca0.2Al2O4 ∶Eu2+, Dy3+ display higher luminescent intensities due to the higher concentration of Eu2+ ions in the host crystal lattice. The decay characteristics of phosphors show that Sr0.6Ba0.2Ca0.2Al2O4 ∶Eu2+, Dy3+exhibit higher intensities in the initial afterglow process and longer afterglow time. The measurement of thermoluminescence reveals that the concentrations and depth of traps can be increased by Ca and Ba co-doping in Sr0.6Ba0.4Al2O4 ∶Eu2+, Dy3+ phosphor.
Solid state dispersions of MoO3 into porous γ-Al2 O3
Authors: Kang Ting-Xia  , Bi Ao-Xiang  , Zhu Jun  ,   Department of Physics, Wuhan University, Wuhan 430072, China
Published: December 2020

A series of the MoO3/γ-Al2O3 samples is prepared by mechanically mixing MoO3 with γ-Al2O3 powder. The solid state dispersion of the MoO3 in to the porous γ-Al2O3 is studied by SEM, XRD, XPS, TG/DTA, and positron annihilation spectroscopy. The positron annihilation lifetime spectra of the MoO3/γ-Al2O3 are measured as a function of the mass ratio of MoO3, heating temperature, heating time and in a way that the MoO3 is loaded gradually, separately. The experimental results show the process of the thermal dispersion of the MoO3 into the γ-Al2O3 support. It is shown that the MoO3 disperses into the outer surface first, and then into the secondary pores and the micro pores. The gradual Loading can make MoO3 effectively dispersed into γ-Al2O3. Grinding can also affecte the thermal dispersion process.
Structural and optical properties of a-Si ∶H/SiO2 multiple quantum wells
Authors: Ma Xiao-Feng  , Wang Yi-Zhe  , Zhou Cheng-Yue  ,   Shanghai Center for Photovoltaics, Shanghai 201201, China
Published: December 2020

a-Si ∶H/SiO2 multiple quantum wells (QWs) are fabricated by plasma enhanced chemical vapor deposition (PECVD) and subsequent different thermal annealing. Among them the annealed sample under 1100 ℃ in vacuum can be transferred into nc-Si:H/SiO2 QWs, and the size of formed nc-Si:H is controllable and it matches the thickness of a-Si ∶H sublayer. The optical absorptivity of a-Si ∶H/SiO2 QWs is compared with that of a-Si ∶H under the same fabrication condition, the former is higher evidently in the UV/Visible spectrum with the absorption edge blue-shifted, which shows that a-Si ∶H/SiO2 QWs has an obvious quantum confinement effect. So it is feasible to use a-Si ∶H/SiO2 QWs to enhance the efficiency of silicon solar cells. In addition, the formation of nc-Si:H/SiO2 QWs with controllable size built the basis for new-type nanocrystalline silicon solar cells.
Regularization method to retrieve synthetic aperture radar sea surface wind
Authors: Jiang Zhu-Hui  , Huang Si-Xun  , He Ran  , Zhou Chen-Teng  ,   Institute of Meteorology, University of Science and Technology of Chinese People’s Liberation Army, Nanjing 211101, China
Published: December 2020

Due to the fact that the error exists in the priori wind direction for the problem of synthetic aperture radar data sea surface wind field retrieval, the regularization method is used to retrieve the wind field, while the L-curve method is adopted to select the optimal regularization parameter. Simulation experiments show that the retrieval accuracy of the regularization method is better than that of the variational method. Further researches in different true wind direction situations indicate that when the real wind direction is in the vicinity of 45 ° or 135 °, the wind speed retrieval accuracy is higher, when the real wind direction is in the vicinity of 0 ° or 90 °, the wind direction retrieval accuracy is higher, this phenomenon may be related to the derivative of backscatter cross section with respect to the wind direction in geophysical model function.
Theoretical investigation on electron transport properties of singlewall carbon nanotube with oxygen molecular absorption
Authors: Zheng Ji-Ming  , Zhao Pei  , Chen You-Wei  , Ren Zhao-Yu  , Guo Ping  ,   (1)Department of Network Engineering, Xian University of Post and Telecommunication, Xian 710121, China; (2)Department of Physics, Northwest University, Xian 710069, China; (3)Institute of Photonics and Photo-technology, Northwest University, Xian 710069, China
Published: December 2020

Electron transport properties of (4,4) single wall carbon nanotube as well as the nanotube with oxygen molecule absorption, are investigated by using first principles analysis. The results show that electron current through the nanotube with oxygen molecule absorption system increases linearly under low bias ranging from 0 to 1.1 V, while the bias is larger than 1.1 V, the current through this system increases slowly. It is also shown that absorbed oxygen molecule brings two kinds of influence on the properties of electron transport: first, the oxygen molecular absorbed states afford new channels to electron transport and enhance the transmission. Second, the oxygen molecular absorbed states spoil the nanotube’s symmetry and enhance the electron scattering, so reduce the transmission.
Electron transport property in wurtzite GaN at high electric field with Monte Carlo simulation
Authors: Guo Bao-Zeng  , Zhang Suo-Liang  , Liu Xin  ,   College of Electronic and Informational Engineering, Hebei University, Baoding 071002,China
Published: December 2020

We present the results of the electron transport property in wurtize GaN using an ensemble full band Monte Carlo simulation. The data of wurtzite GaN band structure calculated with the first-principles total-energy pseudopotential method is used in the simulations. The impact ionization scattering rate is calculated based on Cartier’s method. The average electron drift velocity and the average electron energy each as a function of electric field are computed. The electron impact ionization coefficient is calculated as a function of applied electric field. The analysis of the impact ionization coefficient shows that when the applied electric field is greater than 1 MV/cm, the obvious impact ionization events occur. The analysis of the quantum yield shows that when the electron energy is greater than 7 eV, the quantum yield increases rapidly with electron energy increasing. We study the occupancy of the electrons in the eight conduction bands at the applied electric field ranging from 0 to 4 MV / cm. For the case of the low applied electric field all of the electrons are located in the 1st conduction band. With the increase of the applied electric field, some of the electrons move to high index conduction bands. For the whole range of the applied electric field, most of the electrons are located in the 1st conduction band and 2nd conduction band, a small number of the electrons are located in the 3rd, 4th and 5th conduction band, and very few electrons are located in the 7th and 8th conduction band.
Theorical model of enhanced low dose rate sensitivity observed in p-type metal-oxide-semiconductor field-effect transistor
Authors: Lan Bo  , Gao Bo  , Cui Jiang-Wei  , Li Ming  , Wang Yi-Yuan  , Yu Xue-Feng  , Ren Di-Yuan  ,   (1)Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China; Xinjiang Autonomous Region Key Laboratory of Electronics Information Mater; (2)Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China; Xinjiang Autonomous Region Key Laboratory of Electronics Information Material and Device, Urumqi 830011, China
Published: December 2020

In this paper, the ionizing damage effects and the annealing behaviors of an import producti, p-type metal-oxide-semiconductor field-effect transistor (PMOSFET), an unhardened 4007 circuit under different doses are investigated. We measure the sub-threshold I-V characteristic curves of PMOSFET under different bias doses. The dependence of the drift of threshold voltage on total dose is discussed. We also observe the relationship between the parameter and the annealing time. The experiment results show that the PMOSFET of this kind can enhance low dose rate sensitivity (ELDRS) effect. The interface-trap formation by H+ transmission in the SiO2 is explained.We believe that the interface trap is a primary reason to induce ELDRS effect of PMOSFET. We also discuss the physical model of enhancing low dose rate sensitivity effect of PMOSFET.
a-Si ∶H/a-Si ∶H/μc-Si ∶H triple junction solar cells
Authors: Zheng Xin-Xia  , Zhang Xiao-Dan  , Yang Su-Su  , Wang Guang-Hong  , Xu Sheng-Zhi  , Wei Chang-Chun  , Sun Jian  , Geng Xin-Hua  , Xiong Shao-Zhen  , Zhao Ying  ,   Institute of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Key Laboratory of Opto-electronic Information Science and Technology of Ministry of Educatio
Published: December 2020

Low-cost triple junction solar cells, which much attention has been paid to by industry, are studied in this paper. Based on the amorphous silicon/amorphous silicon tandem solar cells realized in industry using completely single chamber deposition technique, amorphous silicon/amorphous silicon/microcrystalline silicon triple junction solar cell with 9.52% conversion efficiency is fabricated by changing deposition conditions for microcrystalline bottom solar cell and n-p junction in a single chamber developed on our own.
Approximate solution of homotopic mapping for nonlinear vibration problem of transmission line
Authors: Wu Qin-Kuan  ,   Institute of Mathematics, Nanjing Institute of Technology, Nanjing 211167, China
Published: December 2020

A class of dynamical model for the nonlinear vibration of a transmission line is studied. Using the homotopy mapping method, the approximate solution with an arbitrary degree of accuracy is obtained.
Chaos quantum clonal algorithm for spectrum allocation of cognitive wireless network
Authors: Chai Zheng-Yi  , Liu Fang  , Zhu Si-Feng  ,   (1)School of Computer Science and Technology, Xidian University, Xi'an 710071, China; (2)School of Computer Science and Technology, Xidian University, Xi'an 710071, China; School of Information Science and Engineering, Hennan University of Technology, Zhengzhou 450001, China
Published: December 2020

Efficient spectrum allocation of cognitive wireless network is the key technology to dynamic spectrum access. Taking into account the needs of secondary users for the spectrum and the fairness allocation of the spectrum, mathematical model of spectrum allocation is given, and then it is converted into a constrained optimization problem with the goal of maximizing network profits. A chaos quantum clonal optimization algorithm is proposed to solve the problem, and then the convergence of the algorithm with probability 1 is proved. Finally, the simulation experiments are done to test the algorithm. The results show that compared with the color-sensitive graph coloring algorithm, the spectrum allocation based on genetic algorithm, and the spectrum allocation based on quantum-inspired genetic algorithm, the algorithm has good performances. It can achieve the maximization of network profits.
Variation trend of direct and diffuse radiation in China over recent 50 years
Authors: Li Shi-Kui  , Ma Jin-Yu  , Liang Hong  , Luo Yong  ,   (1)Chinese Academy of Meteorological Science, Beijing 100081, China; (2)College of Atmospheric Science, Nanjing University of Information Science and Technology, Nanjing 210044, China; National Climate Center, Beijing 100081, China; (3)National Climate Center, Beijing 100081, China
Published: December 2020

Using the direct and diffuse solar radiation data during 1961—2009 from 14 stations and during 1961—1991 from 49 stations in China, and the method of linear regression (taken time as an independent variable), wavelet analysis and Mann-Kendall statistical test, we analyze the characteristics of the direct and diffusion radiation from different aspects including decadal variation, long-term seasonal change, inter-decadal anomaly, cycle and abrupt change. The results are as follows. 1) The spatial and temporal distribution of the climatic trend for the direct and diffuse radiation are revealed by using the normalized climatic tendency coefficient. At the same time, these results are comparable. 2) The direct solar and diffuse radiation in China show decreasing trend, but there are many differences in region, inter-annual and seasonal trend. 3) Based on the characteristics of the geographical distribution on observation stations and according to the climate zone, the classification and the statistical analysis of the percentage of site occupation the long-term changes of the radiation can be clearly shown to have the characteristics of area and local difference. 4) Using wavelet and Mann-Kendall test method, the statistical results show that the radiations in different regions have different periods and abrupt change. 5)The long-term variations of the direct and diffuse radiation in most big cities turn to decrease more obviously than in other cities. Some. Other studies show that such a climatic phenomenon may be caused by environmental factor change of urbanization related to the difference in development speed between cities.
New infinite sequences exact solutions to sine-Gordon-type equations
Authors: Taogetusang  ,   College of Mathematical Science, Inner Mongolia Normal University, Huhhot 010022, China
Published: December 2020

In order to obtain infinite sequence exact solutions to the sine-Gordon-type equations, the auxiliary equations of triangular function type and hyperbolic function type, Bäcklund transformation and nonlinear superposition formula of the solutions are presented. And the method is used to construct new infinite sequence exact solutions to the sine-Gordon equation, mKdV-sine-Gordon equation, (n+1)- dimensional double sine-Gordon equation and the sinh-Gordon equation with the help of symbolic computation system Mathematica, which include infinite sequence triangular function solutions, the infinite sequence hyperbolic function solutions, infinite sequence Jacobi elliptic function solutions and infinite sequence computation solutions.
Research of quantum secure multi-party ranking protocol
Authors: Liu Wen  , Wang Yong-Bin  ,   School of Computer, Communication University of China, Beijing 100024, China
Published: December 2020

Secure multi-party ranking problem is used to rank n private integers without leaking further information. It is an extended problem of secure two-party comparing problem. A secure multi-party quantum ranking protocol in semi-honest model is presented based on the a quantum implicit module n+1 addition. The security for multi-parties of the protocol is analyzed.
Chaotic communications with multiuser based on unscented Kalman filter
Authors: Hu Zhi-Hui  , Feng Jiu-Chao  ,   School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641, China
Published: December 2020

To reduce effectively channel noise, parameter mismatch, and inter-user interference, a dual unscented Kalman filter (DUFK) algorithm with combining blind extraction algorithm and different state space models for chaotic communication systems with multiuser is proposed. The simulation results indicate that the algorithm has a faster convergence speed and can realize effectively multiuser communications in a multi-input multi-output channel.
Fractional order chaotic system control based on feedback and multiple least square support vector machines
Authors: Wang Rui  , Yang Hong  ,   (1)School of Automation Science and Engineering, South China University of Technology, Guangzhou 510641, China; (2)School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510006, China
Published: December 2020

According to the stability of fractional order linear systems theory, the system is decomposed into stable linear parts and the corresponding nonlinear parts. The active controller is designed to compensate the nonlinear parts, and the fractional order chaotic system is suppressed to an equilibrium point. In order to improve the compensation ability of active controller, a multiple least square support vector machine (M-LS-SVM) regression model is presented based on feedback. The subtractive clustering is adopted to divide the input space into several sub-spaces, and sub-models are built by a LS-SVM in each sub-space. In order to minimize the severe correlation among sub-models and to improve the accuracy and the robustness of the model, the sub-models are combined by principal component regression (PCR).The experiment result shows that by using the method the compensation accuracy and the system response indices can be improved.
Analysis of chaos in doubly fed induction generator and sliding mode control of chaos synchronization
Authors: Yu Yang  , Mi Zeng-Qiang  , Liu Xing-Jie  ,   School of Electrical and Electronic Engineering, North China Electric Power University, Baoding 071003, China
Published: December 2020

The doubly fed induction generator (DFIG) is investigated. Its mathematical model under d-q axis is deduced. According to 2MW mainstream DFIG actual parameters the chaotic behaviors are demonstrated to appear in a certain range of parameter values or under certain working conditions. Based on active control method, an active sliding mode controller is designed, which enables chaotic systems to be stablized under arbitrary initial conditions. The stability of the controlling method is analyzed by Lyapunov stability theorem. Finally, numerical results are presented for the DFIG system. This method may realize the chaos synchronization, and both the stability and the robustness are good.
Methodology of estimating the embedding dimension in chaos time series based on the prediction performance of radial basis function neural networks
Authors: Li He  , Yang Zhou  , Zhang Yi-Min  , Wen Bang-Chun  ,   School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
Published: December 2020

We have studied the methodology of estimating the embedding dimension for phase space reconstruction of chaotic time series according to the Takens theorem. We present an approach to the estimation of the embedding dimension based on the prediction of nonlinear performance. That is, we determine the embedding dimension by considering the variation of the performance of prediction model of chaotic time series with embedding dimension. Numerical simulations verify that the method is applicable for determining an appropriate embedding dimension.
Calculation and analysis of optical flux throughput of interference imaging spectrometer
Authors: Xie Lin-Li  , Li Yan-Na  , Zhang Chun-Min  , Bai Xin  , Jing Chun-Yuan  , Guan Xiao-Wei  , Cao Fen  ,   (1)Key Laboratory for Non-equilbrium Condensed Matter and Quantum Engineering of the Ministry of Education, School of Science, Xi'an Jiaotong University, Xi'an 710049, China; (2)Key Laboratory for Non-equilbrium Condensed Matter and Quantum Engineering of the Ministry of Education, School of Science, Xi'an Jiaotong University, Xi'an 710049, China;Urumchi Xinjiang 21 mail box 189 Sep code, Urumchi 841700, China; (3)Urumchi Xinjiang 21 mail box 189 Sep code, Urumchi 841700, China
Published: December 2020

The principle of interference imaging spectrometer is introduced. In this paper, ray tracing method is employed to present the rules of the prism Sagnac and the polariscope Savart in interference imaging spectrometer. The explicit formulae for the optical feux are deduced. The representative solutions such as the optical fluxes of Savart and Sagnac are both analyzed and compared. By performing the computer simulation, some important curves are obtained for the variations of optical flux with incident angle and wavelength. The work in this paper provides a theoretical guidance for the study of polarization interference imaging spectrometer.
Investigation in discharge progress of a long pulse high power microwave-driven source
Authors: Wang Gan-Ping  , Xiang Fei  , Tan Jie  , Cao Shao-Yun  , Luo Min  , Kang Qiang  , Chang An-Bi  ,   Institute of Applied Electronics, CAEP, Mianyang 621900, China
Published: December 2020

According to the experiment, we analyze the propagation process of the electromagnetic wave on the pulse forming line with water-dielectric, which is the long pulse high power microwave-driven source. And then an equivalent method of discharge process is put forward to study the cause of the flattop waveform distortion. We ind the relationship between the variation trend of the output flattop waveform and the voltage waveform on the pulse forming line, which is validated through the Pspice simulation. By adjusting the breakover time of laser triggered switch, we obtain an output pulse with a flattop of 60 ns, FWHM (full width of half maximum) of 150 ns and voltage amplitude of several hundred kV, showing the distinct improvement on the flattop waveform.
Theoretical study on switching characteristic of photoisomers
Authors: Li Ying-De  , Li Zong-Liang  , Leng Jian-Cai  , Li Wei  , Wang Chuan-Kui  ,   (1)College of Mathematics and Physics, Shandong Institute of Light Industry,Jinan 250353,China; (2)College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (3)College of Physics and Electronics, Shandong Normal University, Jinan 250014, China;College of Physics and Electronis, Weifang University, Weifang 261061, China
Published: December 2020

The electron transport properties of the single molecular junctions composed of isomers of 4,4-(ethene-1,2-diyl) dibenzoic acid and two gold electrodes are investigated systematically using elastic scattering Green's function method. The conductance characteristics are quite different for the two isomers which can be used to construct molecular switch. Our study shows that the molecules are chemically adsorbed on the gold surface by the terminal carboxyl group. Each molecular junction has three different stable conductances, which correspond to the different contact structures between the molecules and electrodes. The different conductances result mainly from the variation of the electronic structures, caused by the interaction between the molecules and the electrodes. Our theoretical simulation is consistent with the experimental measurement.
Visable and ultraviolet upconversion luminescences of Y2O3:Yb3+,Tm3+ nanomaterials
Authors: Li Tang-Gang  , Liu Su-Wen  , Wang En-Hua  , Song Ling-Jun  ,   Key Laboratory of Processing and Testing Technology of Glass & Functional Ceramics of Shandong Province, Shandong Institute of Light Industry,Jinan 250353,China
Published: December 2020

The Y2O3:Yb3+,Tm3+ nanomaterials are prepared by a combustion method. The sample is excited by 980 nm, thereby producing a bright blue emission transition peak (476 nm and 487 nm) and a weak red emission peak(about 650 nm) that can be clearly observed. More important two ultraviolet emission peaks 1I6→3H6 (~297 nm) and 1D2→3H6 (~363 nm) are found. In addition, the change of upconversion emission intensity dependent on the Yb3+ concentrations was recorded and the possible eauses are discussed. Finally, the pump energy dependences of the emission intensity are investigated. The results show that blue and red emissions originate from a three-photon process and ultraviolet emission peak (363 nm) takes its source at a four-photon process.
Rotational excitation of He-BH collision system
Authors: Gong Ming-Yan  ,   Department of Physics, Anhui Normal University, Wuhu 241000, China
Published: December 2020

The dynamics for the collision of BH with He is investigated based on the CCSD(T) potential energy surface. State-to-state differential, partial and integral cross sections are calculated for the first time. The effects of the long-range attractive and the short-range anisotropic interactions on inelastic scattering dynamics are also discussed in detail. As a result, the nearly-linear collision of He atom from H atom side with the BH molecules is the most effective manner for j=0→j'=1.Furthermore, it is of advantage for the Δj=1 transition at lower energy and for the Δj=2 transition at higher energy. The state-to-state integral cross section displays a pronounced oscillatory structure. The long-range partial cross section has only an effect on the integral cross section for j=0→j'=1, and the cross sections for j'≥3 are almost determined by the anisotropic short-rang partial.
Adsorption of H2 on MgO clusters studied by ab initio method
Authors: Chen Hong-Shan  , Chen Hua-Jun  ,   College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Published: December 2020

Based on the most stable structures of the magic MgO clusters, the adsorption of H2 onto the rocksalt and hexagonal tube (MgO)9,12 is studied using first principal method. The results show that physical adsorption can be formed on Mg+q or O-q ions at different sites of the clusters. On the top of the Mg+q ions, H2 is adsorbed in the side-on manner and donates electrons to the ions. On the top of the O-q ions, H2 is adsorbed in the end-on manner and the molecule is polarized. The strength of the adsorption depends mainly on the location of the Mg/O ions, and the smaller the coordination number of the ions, the stronger the adsorption of H2 is. For the Mg/O ions with the same coordination number, the adsorption formed onto the Mg+q is stronger. According to the Mg or O ions and their locations, the adsorption energy ranges from 0.03 eV to 0.08 eV.
Electromagnetic modes in a three-layered structure made of single-negative materials
Authors: Song Ge  , Xu Jing-Ping  , Yang Ya-Ping  ,   Department of Physics, Tongji University, Shanghai 200092, China
Published: December 2020

The modes in a three-layered structure made of single-negative materials have been investigated. For the propagation mode, the tunneling mode can be formed in the structure. When tunneling mode appears the variations of electric field distribution and the transmission with incident angle are studied. We find that there appear two new localized modes when the thickness of the middle layer changes. The frequency interval of the two localized modes can be increased by decreasing the thickness of the middle layer. For the guided mode, the electromagnetic wave is evanescent in semi-infinite vacuum which is on the both sides of the structure. We have analyzed the existence condition of its electromagnetic mode,that is, the dispersion relation. The result shows that a strong local field appears in the interface of the material.
All-dielectric left-handed metamaterial design basedon dielectric resonator theory
Authors: Wang Jia-Fu  , Xia Song  , Xu Zhuo  , Qu Shao-Bo  , Zhao Jing-Bo  , Yang Yi-Ying  , Bai Peng  , Li Zhe  ,   Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China;,   Science College, Air Force Engineering University, Xi'an 710051, China;,   Science College, Air Force Engineering University, Xi'an 710051, China;Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China;,   Synthetic Electronic Information System Research Department, Air Force Engineering University, Xi'an 710051, China
Published: December 2020

By analyzing dielectric cube with high permittivity based on dielectric resonator theory, a new approach to the analyzing of left-handed metamaterials simultaneously with negative permittivity and negative permeability is proposed. The approach indicates that dipoles with Lorentz-type resonance electromagnetic responses can realize negative effective parameters in their negative resonant region. The dipole originates from standing wave in high permittivity dielectric cube. By combining electric dipole with magnetic dipole together, the interaction between two kinds of dipoles will destroy the standing wave and realize a left-handed passband. Numerical simulations indicate that by combining dielectric cubes with same sizes but different permittivities together, the electric resonant frequency and the magnetic resonant frequency can be coincident. Finally, experiments are carried out to verify the feasibility of all-dielectric left-handed metamaterial constructed by this means.
Controllability of random laser output waveshape under femtosecond laser pumping
Authors: Zhu Qi-Hua  , Zhang Qing-Quan  , Lü Jian-Tao  , Wang Ke-Jia  , Liu Jin-Song  , Yao Jian-Quan  ,   Laser Fusion Research Center of the Chinese Academy of Engineer and Physics, Mianyang 621900, China;,   Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;,   Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;College of Precision Instrument and Optoelectronics Engineering,Institute of Laser and Opto
Published: December 2020

The emission property of two-dimensional random laser under femtosecond laser pumping is theoretically investigated by using the time-dependent theory. The effects of peak intensity, duration and shape of a pumping pulse on temporal property of the random laser emission are discussed. Results show that the behavior of random lasing depends strongly on the pumping process, thereby one can control the random laser output waveshape through modifying the pumping parameters. The present work can provide more guidance for the controllability of random laser.
δ-P1 approximation model of biological tissues
Authors: Qi Bei-Bei  , Liu Ying  , Liu Xiao-Jun  , Tian Hui-Juan  ,   (1)College of Science, Tianjin University, Tianjin 300072, China; (2)Key Laboratory of Opt-electronics Information Technical Science, EMC Tianjin University, Tianjin 300072, China; (3)School of Information and Communication Engineering,Tianjin Polytechnic University, Tianjin 300160, China
Published: December 2020

A modified delta-P1 approximation is studied in this paper. An analytic solution Rδ-P1(ρ) of this model for reflectance in double source approximation is developed by taking the source series expansion terms to the first order. It is shown that when the source in extended to first order, a better description for high absorption and high scattering media will be developed. The new model can give satisfactory results in describing irradiance distribution close to source compared with the RSDA(ρ) of diffusion approximation. Moreover, Rδ-P1(ρ) provides the prediction of the second-order parameter γ, which is significant for developing the inversion algorithm to recover optical parameters from spatially-resolved diffuse reflectance by using smaller source-detector separations.
Preliminary theoretical analysis of multi-wavelengthlaser active coherent beam combination
Authors: Han Kai  , Xu Xiao-Jun  , Zhou Pu  , Ma Yan-Xing  , Wang Xiao-Lin  , Liu Ze-Jin  ,   College of Optoelectric Science and Engineering,National University of Defense Technology,Changsha 410073,China
Published: December 2020

In active coherent beam combination (CBC), a single-frequency seed laser is often considered to be indispensable for improving the spatial coherence property and obtaining high brightness in the far field. Nevertheless, the single-frequency radiation restricts the output power of coherently combined fiber amplifiers, owing to low stimulated Brillouin scattering (SBS) threshold. The seed laser oscillating at different frequencies proves to have the potential in mitigating SBS effects in fiber amplifiers, and therefore it is able to increase the emission power of CBC greatly. In this study, the basic mathematical model is founded on the basis of the fundamentals of CBC, and the multi-wavelength two-channel CBC estimation formula is proposed on the calculation of some two-channel examples. The optical path difference is the key factor in multi-wavelength CBC. We propose the concepts of "controllable area" and "uncontrollable area" for the optical path difference. If and only if the optical path difference falls into the controllable area, desirable combination effects can be obtained by the active control. In the case of getting the value of optical path difference randomly, excellent combination effects can still be gained and the probability has a close correlation with the spectrum profile, which is inversely proportional to the number of wavelengths approximatively. The multiple control method is competent for the multi-wavelength CBC. In this method, the optical path difference is adjusted into the controllable area by large optical path controllers and then the phase of each channel is locked by precise optical path controllers.
Evolution of an optical vortex dipole diffracted by a half screen
Authors: Gao Zeng-Hui  , He De  , Lü Bai-Da  ,   (1)Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064, China; (2)Key Laboratory of Computational Physics, Yibin University,Yibin 644000,China; (3)Key Laboratory of Computational Physics, Yibin University,Yibin 644000,China;Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064, China
Published: December 2020

The analytical expression for the propagation of an optical vortex dipole (OVD) nested in a Gaussian beam diffracted by a half screen is derived and used to study the evolution of the diffracted OVD. It is shown that Compared with the case of the OVD evolution in free space, multi-pairs of the OVD may take place in the diffracted field, and the annihilation fashion depends on the off-axis displacement. A variety of the evolution behaviors of OVDs appear by varying the off-axis parameter, but the topological charge is conserved in the evolution process.
Fourier transform profilometry of tilted measurement system
Authors: Xu Jian-Liang  , Wang Min  , Pan Hui  , Liu Xiao-Hui  , Qi Xiao-Li  , Xu Si-Xiang  ,   School of Mechanical Engineering, Anhui University of Technology, Maanshan 243002, China
Published: December 2020

Based on the resarch of the traditional Fourier transform profilometry, Fourier transform profilometry of tilted measurement system is proposed in this paper. The proposed technology makes the three constraints of the traditional Fourier transform profilometry measurement system less stringent. The optical axis in the CCD imaging system is not necessarily perpendicular (with a certain tilting angle) to the reference plane. The connection line between the centers of the exit pupil of the projecting system and the entrance pupil of the CCD imaging system is not required to be horizontal to the reference plane. The optical axis of the CCD imaging system and that of the projecting system are not coplanar, moreover, the two axises do not intersect at a point in the reference plane. Through the stringent theoretical analysis, the mathematical relationship between phase and height is obtained. Compared with the traditional Fourier transform profilometry, the tilted measurement system is more practical.
Relaxation time for an optical bistable system subjected to cross-correlated color noises
Authors: Wang Bing  , Wu Xiu-Qing  ,   Department of Physics and Mathematics, Anhui University of Science and Technology, Huainan 232001, China
Published: December 2020

Investigated are the effects of the cross-correlation time τ or the self-correlation times τ1 and τ2 on the relaxation time T of an optical bistable system using the Mei's method(Mei D C, Xie C W, Zhang L 2003 Phys. Rev. E 68 051102). It is found that the relaxation time T increases with the increase of the cross-correlation time τ between the two noises or the self-correlation time τ1 of the multiplicative noise, and that a one-peak structure appears on the T－τ2 plot. T increases with the increase of correlation intensity λ but decreases with the increase of multiplicative noise intensity Q.
Theoretical study on large phase shift of strongly nonlocal spatial optical soliton and its application design
Authors: Shou Qian  , Guo Qi  ,   Key laboratory of Photonic Information Technology of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510631, China
Published: December 2020

Compared with local spatial optical solitons and linearly propagating beams, nonlocal spatial optical solitons each have a large phase shift during their propagation. However no one has paid attention to the intrinsic characteristics since the theoretical proof by Guo. We develop the phenomenological theory of Guo and find that there appears π phase shift with the change of the soliton power or the power of the pump soliton. Based on the conclusion that the modulation of the pump-soliton power on the signal-soliton phase has a high sensitivity, we propose a feasible scheme of realizing the optical switch.
Asymmetrical collision among coherentphotovoltaic spatial solitons
Authors: Li Xiang-Heng  , Zhang Bing-Zhi  , She Wei-Long  ,   State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China
Published: December 2020

Asymmetrical collisions among three coherent photovoltaic spatial solitons are investigated by numerical method. The numerical results show that the solitons will split or annihilate depending on the incident angle of signal beams in a certain range. If we only change the initial phase difference among the solitons, the collision behavior of solitons will also change correspondingly, showing an interesting conversion of split between annihilation. Furthermore, the numerical results show that the photovoltaic spatial solitons will maintain conservations of momentum and energy in these collision processes, although the dynamical system of photovoltaic solitons is a non-integrable Hamilton one.
A hybrid algorithm for the transient scattering from a two-dimensional conductor target above a randomly rough surface
Authors: Guo Li-Xin  , Qin San-Tuan  , Gong Shu-Xi  , Dai Shao-Yu  ,   (1)Key Laboratory of Antennas and Microwave Technology, Xidian University, Xi'an 710071, China; (2)School of Science, Xidian University, Xi'an 710071, China
Published: December 2020

A hybrid algorithm of time domain integral equation (TDIE) and time domain Kirchhof approximation (TDKA) is proposed to compute the TM transient scattering from a 2-dimensional (2D) perfectly conducting (PEC) target above 2D PEC randomly rough surface. Explicit and implicit procedures of Marching-on-in-time (MOT) are developed, respectively. TDKA is applied to the rough surface while TDIE is applied to the target, and the mixed iteration of TDIE/TDKA is introduced to take into account the interactions between the target and the rough surface. In numerical examples, both bent strip (open structure) and cylinder (closed struc- ture) are considered and numerical results present the target surface current response and the far scattered electric field response, which are compared with those obtained from whole TDIE. Numerical results demonstrate the efficiency and the accuracy of the hybrid algorithm. Still in numerical examples, the influence on the far scattered electric field caused by the target is discussed.
Magnetically tunable magnetic photonic crystal forterahertz switch and filter
Authors: Guo Zhan  , Fan Fei  , Bai Jin-Jun  , Niu Chao  , Chang Sheng-Jiang  ,   Institute of Modern Optics, Nankai University, Key Laboratory of Optoelectronic Information Science and Technology, Ministry of Education, Tianjin 300071, China
Published: December 2020

The feasibility of ferrite magnetism materials applied to THz waveguide devices is investigated. A novel continuously tunable bandpass filter and switch under the control of an external magnetic field in a terahertz wave band are designed. Detailed calculations on the shift and the variation in the position of the bandgap reveal that the filter and the switch achieved by this two-dimensional magnetic photonic crystal waveguide have good performancs.
Temperature characteristic of photonic crystals resonant cavitycomposed of GaAs pillars with graphite lattice
Authors: Li Yan  , Fu Hai-Wei  , Shao Min  , Li Xiao-Li  ,   Shool of Science, Xi'an Shiyou University, Xi'an 710065, China
Published: December 2020

A model of two-dimensional photonic band gap structure resonant cavity composed of GaAs pillars with graphite lattice is proposed. The variation of its TEy mode formant wavelength with temperature is calculated by finite difference time domain method. The results show that there is a sectional linear characteristic between the main formant wavelength and temperature for this kind of photonic crystal resonant cavity, and the sensitivity responding to temperature is more than 1.60nm/℃. At the same time, the results show that this kind of resonant cavity possesses an excellent characterisitc of frequency switching. Finally, the cause for its switching characteristic is explained by the calculated results.
A novel approach to research on feature extraction of acoustictargets based on manifold learning
Authors: Liu Hui  , Yang Jun-An  , Wang Yi  ,   Department of Information,Electronic Engineering Institute of PLA,Hefei 230037,China
Published: December 2020

In order to overcome the deficiency of robustness of low altitude passive acoustic target recognition, the manifold learning is applied to the feature extraction of acoustic targets. Based on the classical algorithm of manifold learning, in the paper we study and discuss the low-dimensional manifold in the frequency-domain of acoustic signals. This method is used to solve the target recognition problem with two data sets to verify its effectiveness, after which the performance is analyzed. The result indicates that the manifold learning can discover the intrinsic feature and increase the accuracy and the robustness of low altitude passive acoustic target recognition system.
Three-dimensional microwave-induced thermo-acousticimaging for breast cancer detection
Authors: Liu Guang-Dong  , Zhang Ye-Rong  ,   College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210003, China
Published: December 2020

We propose a three-dimensional (3D) microwave-induced thermo-acoustic imaging technique for early-stage breast cancer detection, which offers a high imaging contrast and high spatial resolution. The robust Capon beam-forming (RCB) algorithm, which is a data-adaptive approach, is considered for signal processing and image formation. The finite-difference time-domain (FDTD) method is applied to electromagnetic simulation as well as acoustic simulation. The feasibility of this technique is demonstrated via a numerical example based on a 3D breast model.
Effect of damping on segregation of size-type binary granularsystems in a rotating horizontal drum
Authors: Gao Hong-Li  , Zhao Yong-Zhi  , Liu Ge-Si  , Chen You-Chuan  , Zheng Jin-Yang  ,   (1)Department of Chemical and Biochemical Engineering, Institute of Process Equipment,Zhejiang University, Hangzhou 310027, China; (2)Department of Chemical and Biochemical Engineering, Institute of Process Equipment,Zhejiang University, Hangzhou 310027, China;Guangdong University of Petrochemical Technology, Maoming 525000, China
Published: December 2020

In this paper, the segregation patterns of size-type binary granular systems with different damp coefficients in a rotating horizontal drum are simulated by the discrete element model. The process and the mechanism of segregation are studied, and the effects of damping on segregation model of size-type binary granular system in a rotating horizontal drum are discussed. The simulation results show that the segregation process and the flow pattern of granulae in a flowing layer depend strongly on damping. According to the simulation results we predict that the radial segregation patterns that form in a size-type binary granula system in a thin rotating horizontal drum will be the sun pattern when the damp coefficients is in a middle value range, otherwise, the moon pattern will appear.
Inertial and elastic-plastic effect on spallationdamage of ductile metals
Authors: Zhang Feng-Guo  , Zhou Hong-Qiang  , Zhang Guang-Cai  , Hong Tao  ,   Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
Published: December 2020

The influences of inertia, elastic-plastic effect and initial void size are studied on the damage evolution in spallation of ductile metals under planar impact loading by using the hollow spheroid model. Numerical analysis indicates that inertia, elastic-plastic effect and initial void size each have a significant influence. Influence of Initial damage or initial void size on spallation damage cannot be neglected. In this paper we attempt to develop a method to analyse initial void size due to its importance on spallation damage.