bluuebunny/crossref_metadata_2025 huggingface dataset:
The theoretical study on CH4 adsorption in different zeolites
Authors: Liu Xiu-Ying  , Li Xiao-Feng  , Zhang Li-Ying  , Fan Zhi-Qin  , Ma Xing-Ke  ,   College of Science, Henan University of Technology, Zhengzhou 450000, China;,   College of Physics and Electronic Information, Luoyang Normal College, Luoyang 471022, China
Published: December 2020

The physisorption properties of CH4 in MOR and MFI zeolites are studied using the grand canonical Monte Carlo method. Some important physical quantities are obtained, such as adsorption amounts, isosteric heats, interaction energies of zeolite, CH4 molecules, etc. The results show that the physisorption properties of MOR zeolite are superior to those of MFI zeolite in all conditions. The reasons causing such different results between them are analyzed from the interaction energies between zeolites and CH4 molecules, the relationships between isosteric heats and adsorption amounts, etc.
First-principles study of Be, O codoped p-type AlN
Authors: Yuan Di  , Huang Duo-Hui  , Luo Hua-Feng  ,   Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China;,   Department of Physics and Electronic Engineering, Yibin University, Yibin 644007, China
Published: December 2020

By using the first-principles ultrasoft pseudo-potential approach of the plane wave based on the density functional theory, the electronic structures and their changes, the bandstructures, the densities of states, and the charge densities of pure Be-doped and Be-O codoped wurtzite AlN are calculated. The calculation results reveal that Be-doped wurtzite AlN gives rise to the formation of deep Be acceptor levels in the band gap and the carriers (hole) are localized near the top of the valence band, and the introduction of activated donor O atoms makes the acceptor level wider and the non-local characteristics distinctive, and can cause the primary level to shift toward the low energy, forming a shallow acceptor level, thereby enhancing the doping concentration of Be atoms and the stability of the system. Be, O co-doped p-type is more conducive to obtaining AlN.
Effect of doping concentration on electric-pulse- induced resistance in Nd1-xSrxMnO3 ceramics
Authors: Chen Shun-Sheng  , Yang Chang-Ping  , Xiao Hai-Bo  , Xu Ling-Fang  , Ma Chang  ,   School of Mathematics and Physics, Hubei Polytechnic University, Huangshi 435003, China;,   Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062, China
Published: December 2020

Electric-pulse-induced resistances (EPIRs) and I-V characteristics of polycrystalline Nd1-xAxMnO3 (A = Ca, Ba, Sr, x = 0-0.9) ceramics synthesized by solid state reaction are investigated. The results show that similar to Nd0.7Sr0.3MnO3, compounds Nd0.7Ba0.3MnO3 and Nd0.7Ca0.3MnO3, with the same doped concentration as that of Nd0.7Sr0.3MnO3, can also exhibit a nonlinear I-V behaviour and a stable EPIR effect at room temperature. Further studies on the Nd1-xSrxMnO3 series indicate that the stability of EPIR is closely correlated with the Sr doped concentration. Around the half doping x= 0.5, the EPIR effect can be observed stably. With Sr concentration increasing or decreasing, however, the EPIR becomes weaker gradually and disappears completely if Sr concentration further increases or decreases. The redistribution of various defects between the electrode and bulk interface with polar pulses is proposed to explain the unique transport behaviour.
Preliminary investigation on the method of determining electron mobility of tris (8-hydroxyquinolinato) aluminum by space charge limited current
Authors: Luo Yang  , Duan Yu  , Chen Ping  , Zang Chun-Liang  , Xie Yue  , Zhao Yi  , Liu Shi-Yong  ,   State Key Laboratory on Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, China
Published: December 2020

The charge-carrier mobility of an organic semiconducting material determines the material potential applications in devices. The investigation on mobility of organic material plays a significant role in improving the performance of organic device, such as organic light emitting diode, organic solar cell and organic thin film transistor. In this paper, we employ the space charge limited current (SCLC) method to evaluate the electron mobility of the controlled device based on tris (8-hydroxyquinolinato) aluminum (Alq3). The zero-field mobilities and field-dependent factors of the four devices are fitted respectively. The results show that depositing Al as top-electrode onto buffer layer LiF (1 nm) and Alq3 (100 nm) can significantly improve the the zero-field mobility and field-dependent factor of Alq3. The reason for that is that LiF could strengthen the complex reaction between Al and Alq3 to form Li+1Alq-1 particles, which leads to the enhanced ohmic injection and electron injection.
Study of characteristics of plume based on hue-saturation-intensity during high-power disk laser welding
Authors: Gao Xiang-Dong  , Wang Run-Lin  , Long Guan-Fu  , Katayama Seiji  ,   Faculty of Mechanical and Electrical Engineering, Guangdong University of Technology, Guangzhou 510006, China;,   Joining and Welding Research Institute, Osaka University, Osaka 567-0047, Japan
Published: December 2020

During high-power disk laser welding, the surface of the weldment is gasified strongly by the laser irradiation. Meanwhile, the metal vapor plume is generated and changed into the plasma state. This plume can transmit through the laser beam reversely and has a significant shielding effect on the laser beam. Therefore, the laser power which should be transferred inside the weldment is decreased, the welding efficiency and welding quality are seriously affected. By studying and exploring the relation between the characteristics and variation rules of plume and the welding quality, the state of laser welding can be monitored in real-time by the plume characteristics. In the high-power disk laser bead on plate welding of a type 304 austenitic stainless steel plate at a continuous laser power of 10 kW, an extraviolet and visible sensitive high speed color camera is used to capture the metal vapor plume dynamic images. These digital images are transfered to the hue-saturation-intensity color spaces from the red-green-blue color spaces. Also, the area of metal vapor plume and the path length which the laser beam runs through the metal vapor plume are segmented and defined as the plume eigenvalues. The fluctuation of weld bead width is used to evaluate the stability of welding quality. By analyzing the statistics of the variance and mean values of plume eigenvalues, the experimental results confirm that the stability of the welding could be evaluated by the plume characteristics dynamically.
The formation mechanism of the silicon nano-clusters embedded in silicon nitride
Authors: Zou Xiang-Yun  , Yuan Jin-She  , Jiang Yi-Xiang  ,   Department of Physics, Chongqing Normal University, Chongqing 400047, China;,   The Key Laboratory of Optical Engineering, Chongqing 400047, China
Published: December 2020

The silicon nitride films are prepared on c-Si substrates by plasma enhanced chemical deposition (PECVD) with silane as the silicon source in mixture gas (N2/NH3) as the nitrogen source. We prepare different kinds of films at different flow rates of the nitrogen with other conditions kept the same. X-ray diffraction (XRD) is employed to analyze the crystal structure, and the existence of the silicon nanoparticles embedded in the silicon nitride film is verified according to the caculation of the lattice size. Fourier transform infrared spectra are employed to probe the concentration evolutions of various chemical bonds with the flow rate of the nitrogen, with which by combining the chemical reaction process, the formation mechanism of the silicon nano-clusters embedded in silicon nitride is investigated. The results show the initial positions of silicon nanoparticles are conducible to the formation of silicon nanoparticles when the chemical reaction proceeds towards the direction in which the SiSi bonds form. In addition, XRD analysis and photoluminescence characteristics show that the size and the concentration of the embedded nanoparticles increase with the flow rate of the nitrogen increasing.
Ocean surface wind direction retrieval from multi-polarization airborne SAR based on wavelet
Authors: Ai Wei-Hua  , Kong Yi  , Zhao Xian-Bin  ,   Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101, China
Published: December 2020

An ocean surface wind direction retrieval method from multi-polarization airborne synthetic aperture radar images is presented in order to retrieve high precision wind direction SAR image and improve the accuracy of ocean surface wind. The method relies on the ability of two-dimensional (2D) continuous wavelet technique with better time-frequency than Fourier transform and local gradient, which combines 2D continuous wavelet and FFT to exact the ocean surface wind direction from airborne SAR images. The proposed method is executed by using several kinds of mother wavelet functions for the C-band co-polarization and cross-polarization airborne sounding images, and the retrieved ocean surface wind direction is compared with NCEP data and buoy data. The verification results show that the wavelet based ocean surface wind direction retrieval algorithm is suited to retrieve wind direction from airborne SAR sounding data. The choice of mother wavelet function has a certain influence on the results, and 2D Mexican-Hat is the best mother wavelet for wind retrieval. Both co-polarization and cross-polarization airborne sounding images are suited to retrieve ocean wind direction.
The application of phase contrast imaging to implosion capsule diagnose in high energy density physics environment
Authors: Yan Ji  , Zheng Jian-Hua  , Chen Li  , Lin Zhi-Wei  , Jiang Shao-En  ,   Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The variation of multi-layer shell capsule in implosion process is the most important part of inertial confinement fusion. Phase contrast imaging which relies on gradients of the refractive index and wave interference is proposed to characterize the typical implosion capsule. The experiments are performed on the Shenguang Ⅱ laser facility. The point-like X-ray source at 4.75 keV can be efficiently produced from laser interactions with Ti target and observed by pinhole- point backlight technique. The phase contrast images obtained with point-like X-ray source provide complementary information about the multi-layer shell capsule, and the spatial resolution is better than 10 μm. The X-ray phase contrast imaging shows more detailed features than absorb imaging, and good agreement with one-dimensional numerical simulations.
A new method of analoguedynamical prediction of monsoon precipitation based on analogue prediction principal components of model errors
Authors: Xiong Kai-Guo  , Zhao Jun-Hu  , Feng Guo-Lin  , Huang Jian-Ping  , Hu Jing-Guo  ,   Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China;,   Laboratory for Climate Studies, National Climate Center, China Meteorological Administration, Beijing 100081, China;,   College of Physics Science and Technology, Yangzhou University, Yangzhou 225009, China
Published: December 2020

To correct the model errors in analogue-dynamical prediction, a new idea of using the analogue prediction of principal components of model errors, instead of analogue prediction of model error directly, is proposed. By decomposing the empirical orthogonal function, the principal components of the model errors are divided into two parts subjectively: predictable and unpredictable. For the predictable part, it is analogically predicted by the scheme of dynamical and optimal configuration of multiple predictors; while for the unpredictable part, it is estimated by average of the system. Based on the National Climate Center (NCC) of China operational seasonal prediction model results for the period 1983-2010 and the US National Weather Service Climate Prediction Center merged analysis of precipitation in the same period, together with the 74 circulation indices of NCC Climate System Diagnostic Division and 40 climate indices of NOAA of US during 1951-2010, the method is implemented in objective and quantitative prediction of monsoon precipitation in Northeast China. The independent sample validation shows that this technique has effectively improved the monsoon precipitation prediction skill during 2005-2010, for which the averaged anomaly correlation coefficients and the system correct of errors are 0.29 and 0.04 respectively. This study demonstrates that the analogue-dynamical approach can enhance the prediction level of NCC operational seasonal forecast model obviously.
Consensus analysis of multi-agent system with multiple time delays
Authors: Ji Liang-Hao  , Liao Xiao-Feng  ,   State Key Lab. of Power Transmission Equipment & System Security and New Technology, College of Computer Science, Chongqing University, Chongqing 400044, China;,   College of Computer Science and Technology, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
Published: December 2020

Consensus problems of first-order and second-order multi-agent system with communication delays and input delays are proposed based on the frequency-domain analysis and generalized Nyquist criterion. Supposing that the topology of the multi-agent system is fixed, asymmetrically interconnected digraph and owns a globally reachable node, the sufficient condition for system convergence is obtained. The results show that the condition of convergence is dependent only on system coupling strength, each agent input time delay and the adjacent weights to its neighbors, but independent of communication delay which can affect the dynamics of the system. Finally, simulations are provided to demonstrate the effectiveness of our theoretical results.
A probable explanation for bat's auditory nervous system identifying inserts in the complex surrounding
Authors: Ding Jiong  , Zhang Hong  , Tong Qin-Ye  ,   Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, China;,   Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang University 310027, China;,   Center of Neural Information Research, Zhejiang University, Hangzhou 310027, China
Published: December 2020

The high sensitivity and reliability of the biosonar have attracted many bionic scientists' attention. However, there is no convincing physical model to explain the reasons of the superior performance of biosonar. The main reason is that the neuron coding of the nervous system is still uncertain. Based on the physiological structure of the bat's auditory nervous system, a probable explanation is proposed to discuss the Doppler signal process with the principle of circle maps and symbolic dynamics. Through the computer simulation, the rationality of this method is proved. For the instability of the nervous system, using symbolic dynamics to analye the mechanism of the neural information processing has high sensitivity and robustness. It is expected that the research of this new explanation will be able to promote the understanding of the biosonar signal processing and its applications.
Investigation of polarization-induced phase noise in interferometric optical fiber sensing system based on FRM
Authors: Wang Jian-Fei  , Wang Xiao  , Luo Hong  , Meng Zhou  ,   College of Optoelectronic Science and Technology, National University of Defense Technology, Changsha 410073, China
Published: December 2020

One of the key technologies of interferometric optical fiber sensing system is to overcome polarization-induced signal fading in interferometric fiber sensors. The theoretical and the experimental investigations of the residual polarization-induced phase noise (PIN) in single-mode optical fiber Michelson interferometer based on Faraday rotation mirror (FRM) are conducted in this paper. A theoretical model of the residual PIN based on Jones matrix is developed. Three leading influencing factors of the residual PIN are educed: the rotation deviation angle of FRM, the state of polarization of input light, and the birefrigent effect of the optical fiber. And three methods are proposed to overcome the residual PIN. The maximal PIN with its amplitude of 0.0815 rad possibly exists in the sensing system when the polarization modulation degree equals 1.84 rad. The correctness of the theoretical model is proved by the experimental results.
Study of molecule spectra of carotenoid
Authors: Fang Wen-Hui  , Li Zuo-Wei  , Li Zhan-Long  , Qu Guan-Nan  , Ouyang Shun-Li  , Men Zhi-Wei  ,   State Key Laboratory of Superhard Materials, Jilin University, Changchum 130012, China;,   College of Physics, Jilin University, Changchun 130012, China
Published: December 2020

Carotenoid is a short-chain polyene biomolecule of 9 CC conjugate double-bonds. Due to its special structure carotenoid is used not only in photoprotection and anti-cancer, but also in molecule wires, light switch, and light filter. In this paper molecule spectra of carotenoid are studied. The carotenoid has the broadband fluorescence, the broadband stimulated Raman scattering is obtained when the fluorescence of carotenoid is used to enhance stimulated Raman scattering. Electron energy gap of carotenoid becomes narrow with temperature decreasing, and absorption spectra are red-shifted. These characteristics can make the carotenoid a high-quality semiconductor component. Raman active is intensive and the 3rd order optical nonlinear coefficient is large. The Raman scattering cross section of CC bond is about 10 orders of magnitude larger than that of common molecule. The Raman scattering intensity of overtone is intensive: the ratio of overtone to basic frequency is around 0.5 at low temperature. These spectrum characteristics of carotenoid are significant for studying polyene molecule structure, property and non-biology domain.
Quasi-classical trajectory approach to the influence of the rotational excitation on the stereodynamics of the reaction O+HBrOH+Br
Authors: Li Hong  , Zheng Bin  , Meng Qing-Tian  ,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

Quasi-classical trajectory method is used to investigate the influence of rotational excitation on the vector properties of the dynamics for the reaction O+HBrOH+Br based on the abinitio potential energy surface. At the collision energy 0.3 eV, we discuss the polarization-dependent differential cross sections (PDDCSs), the distribution P(r) describing k - j correlation, and the distribution P(r) describing k - k- j correlation. The calculated results suggest that the product rotational polarization becomes weaker as the rotational quantum number increases and the products are mainly forward scattered.
Broadband and low-loss left-handed metamaterial composed of oblique triangular open-loop pairs resonator
Authors: Li Wen-Qiang  , Cao Xiang-Yu  , Gao Jun  , Liu Tao  , Yao Xu  , Ma Jia-Jun  ,   Telecommunication Engineering Institute of Air Force Engineering University, Xi’an Shannxi 710077, China
Published: December 2020

A method of realizing multiband and broadband left-handed metamaterials with low-loss is presented. By integrating oblique triangular open-loop pair resonator plus wire (OTOR-wire) with oblique triangular open-loop pair resonator (OTOR), the combined structure exhibits double LH passbands, which can form broad LH passband by adjusting the unit cell geometrical dimension. Simulation and experimental results and analysis demonstrate that this structure exhibits negative effective permittivity and permeability simultaneously in a frequency range from 9.3 GHz to 13.2 GHz, its relative negative refraction passband reaches 347%, and the figure of merit reaches 347.9. The idea can help us to design multiband and broadband left-handed metamaterials with low-loss
An investigation of partial field decomposition using pressure gradient reference
Authors: Bi Chuan-Xing  , Guo Ming-Jian  , Zhang Yong-Bin  , Xu Liang  ,   Institute of Sound and Vibration Research, Hefei University of Technology, Hefei 230009, China
Published: December 2020

The incoherent sound field obtained by scanning measurement cannot be used directly for nearfield acoustic holography to reconstruct the sound field. And therefore, the incoherent sound field needs to be decomposed into fully coherent partial fields. In previous methods, the pressure is used as reference to obtain the partial fields. In this paper, the pressure gradient is used as the reference for the partial field decomposition. Because the pressure gradient decays faster than the pressure, the interaction of the pressure gradient between the incoherent sources is weaker than that of the pressure, which may improve the effect of the partial field decomposition. A numerical simulation and an experiment are conducted to test the feasibility of the method. And it is shown that the partial field decomposition method based on pressure gradient reference is robust and the decomposed results are better than those based on pressure references.
Approximae solution for a class of the disturbed evolution equation
Authors: Du Zeng-Ji  , Mo Jia-Qi  ,   School of Mathematical Sciences, Jiangsu Normal University, Xuzhou 221116, China;,   Department of Mathematics, Anhui Normal University, Wuhu 241003, China
Published: December 2020

A class of disturbed evolution equation is considered by a simple and valid technique. We first introduce the traveling solitary wave solution of a corresponding typical differential equation, and then use the asymptotic method to obtain the approximate solution for an original disturbed evolution equation. And we point out that the series of approximate solution is convergent and the precision of the approximate solution is discussed by using the fixed point theorem for the functional analysis.
Influence of gas type on velocity splitting of ablated particles
Authors: Ding Xue-Cheng  , Fu Guang-Sheng  , Chu Li-Zhi  , Deng Ze-Chao  , Liang Wei-Hua  , Zhao Ya-Jun  , Wang Ying-Long  ,   College of Physics Science and Technology, Hebei Key Laboratory of Optic-electronic Information & Materials, Hebei University, Baoding 071002, China
Published: December 2020

The transport dynamics of the ablated particles is simulated via Monte Carlo simulation. The influences of ambient gases (He, Ne, and Ar dummy gas) on velocity splitting of the ablated particles under 100 Pa are investigated. The results show that the velocity splitting appears in four types of gases. The formation times of velocity splitting of the ablated particles decrease in sequence of He, Ne, dummy gas and Ar. The influences of the mass and radius of ambient gas molecule on the velocity splitting are also investigated. The formation time of the velocity splitting decreases with mass/radius of ambient gas molecule increasing. The intensity is the smallest when the two velocity peak intensities are equal. The formation time of velocity splitting is explained by the underdamping oscillation model and the inertia fluid model. These results give a good foundation for the further study of the Si nanoparticle growth.
Spectral response calibration of Au and CsI transmission photocathodes of X-ray streak camera in a 605500 eV photon energy region
Authors: Zeng Peng  , Yuan Zheng  , Deng Bo  , Yuan Yong-Teng  , Li Zhi-Chao  , Liu Shen-Ye  , Zhao Yi-Dong  , Hong Cai-Hao  , Zheng Lei  , Cui Ming-Qi  ,   Department of Engineering Physics, Tsinghua University, Beijing 100084, China;,   Research Center of Laser Fusion, CAEP, P. O. Box 919-986, Mianyang 621900, China;,   Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

A method is described of measuring absolute spectral response for Au and CsI transmission photocathodes in soft X-ray streak camera, which is of great importance for the inertial confinement fusion (ICF) diagnostics. Transmission photocathode is conventionally employed as photo-to-electron conversion accessories. To derive quantity information of X-ray spectra, the absolute response of photocathode must be calibrated in a range of interest. Here Au and CsI transmission photocathodes with slits are calibrated respectively on Beijing Synchrotron Radiation Facility (BSRF), in a photon energy range of 60 eV5500 eV. This method has an uncertainty less than 10% and good feasibility. Calibration results are in good agreement with the calculation results obtained from the Henke's photon emission model, with CH substrate effect revised.
Effects of preparation temperature of graphite oxide on the structure of graphite and electrochemical properties of graphene-based lithium-ion batteries
Authors: Huang Le-Xu  , Chen Yuan-Fu  , Li Ping-Jian  , Huan Ran  , He Jia-Rui  , Wang Ze-Gao  , Hao Xin  , Liu Jing-Bo  , Zhang Wan-Li  , Li Yan-Rong  ,   State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Graphite oxide is synthesized from graphite powder by a modified Hummers method, and the oxidation temperature is controlled in high-temperature oxidation process. By treating graphite oxide powders in a commercial microwave oven, graphene materials can be readily obtained. The morphologies, microstructures, specific surface areas and other features of the graphene and graphite oxide are characterized by FESEM, XPS, XRD and BET. Electrochemical performances of the lithium-ion batteries based on graphene anodes are investigated. The results show that graphene obtained at the oxidation temperature of 90℃ in high-temperature oxidation process actually displays the most remarkable electrochemical performances, that is, the first discharge specific volume and charge capacity of graphene are as high as 1555.5 mAh/g and 1024.6 mAh/g, and after 30 cycles graphene still possess as high as a discharge capacity of 600 mAh/g.
Elastic-plastic response of shocked 100 LiF and its window correction at 1550 nm wavelength
Authors: Li Xue-Mei  , Yu Yu-Ying  , Zhang Lin  , Li Ying-Hua  , Ye Su-Hua  , Weng Ji-Dong  ,   National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

By using plate impact and laser interferometry technology, careful experiments and theoretical analysis for 100 LiF are carried out for its dynamic mechanical response and optical characteristics under shock pressures up to 40 GPa. The accurate shock Hugoniot relation and velocity correction at 1550 nm wavelength are then obtained. Moreover, the direct wave-profile measurments show that LiF keeps an obvious elastic-plastic response within 20.3 GPa, and the estimated lower limit pressure for single-wave shock response is about 2223 GPa. The strength influence of LiF window on the dynamic behavior of the sample should be taken into account in precise experiments with shock pressure lower than this range. The results above establish foundations for the design and data post-processing of shock experiments in which LiF is used as an optical window for the dynamic material properties such as elasto-plasticity, phase transition and melting.
Spin-polarized transport through double quantum-dot-array
Authors: An Xing-Tao  , Mu Hui-Ying  , Xian Li-Fen  , Liu Jian-Jun  ,   School of Sciences, Hebei University of Science and Technology, Shijiazhuang 050018, China;,   Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;,   Department of Chemistry and Environmental Engineering, Hebei Chemical and Pharmaceutical Vocational Technology College, Shijiazhuang 050026, China;,   Physics Department, Shijiazhuang University, Shijiazhuang 050035, China
Published: December 2020

The spin-dependent transport through double quantum-dot-array coupled to a single quantum dot is studied by using the non-equilibrium Green function formalism. Due to the quantum interference and the spin-dependent phase induced by Rashba spin-orbit interaction, the spin of the electron through the device is polarized. When the energy level of quantum dot is in the bias window, the spin accumulation in the single quantum dot can maintain a large value in a wide range of energy and the quantum dot is largely spin polarized. The spin accumulations in the single quantum dot under positive bias and negative bias are absolutely different because of asymmetric quantum dot structure. These results is helpful for designing and fabricateing the practical spintronics devices.
Intermittent superconductivity in mesoscopic thin-film rings
Authors: Shi Liang-Ma  , Liu Lian-Zhong  , Wang Xiang-Xian  , Zhu Ren-Yi  ,   Department of Physics and Electronics, Chaohu College, Chaohu 238000, China;,   School of Information and Computer Science, Anhui Agricultural University, Hefei 230036, China
Published: December 2020

Intermittent superconductivity for mesoscopic thin-film rings is investigated by the phenomenological Ginzburg-Landau theory. Phase diagram for intermittent superconductivity vs. ring dimension is given in the presence of an external applied field. The intermittent superconductivity exists only in the small ring, which is a feature for distingushing superconductive ring from superconductive disk.
Thermoluminescence and optically stimulated luminescence characteristics of -Al2O3:C crystal powder of different particle size
Authors: Hu Ke-Yan  , Li Hong-Jun  , Xu Jun  , Yang Qiu-Hong  , Su Liang-Bi  , Tang Qiang  ,   Department of Electronic Imformation Materials, Shanghai University, Shanghai 201800, China;,   Shanghai Institute of Ceramics, Chinese Academy of Sciences , Shanghai 201800, China;,   Department of Physics, Sun Yat-Sen University, Guangzhou 510275, China
Published: December 2020

In this work, we first report on the radiation dose effect of -Al2O3:C crystal powder. The thermoluminescence(TL) and optically stimulated luminescence (OSL) of the powder are investigated by RisTL/OSL-DA-15. The as-grown -Al2O3:C crystal powder of same particle size shows a single TL peak and the TL intensity increases as irradiation dose increases, but no shift of the position of the TL peak is found, which is consistent with first-order recombination kinetics. And in the same radiation dose and test conditions, with the particle size of -Al2O3:C crystal powder decreasing, the TL intensity decreases after first increase and then the TL peak is gradually increases and approaches to a stable value, which shows that the -Al2O3:C crystal powder, 4060 m in diameter, has the best TL effect. The OSL decay curve of -Al2O3:C crystal powder shows the typical exponential decay characteristics, and the relationship between OSL intensity and decay rate with the particle size of -Al2O3:C crystal powder is found to be consistent with the shallow-electronic-trap theory.
The characterization of hydrogenated amorphous silicon and epitaxial silicon thin films grown on crystalline silicon substrates by using spectroscopic ellipsometry
Authors: Wu Chen-Yang  , Gu Jin-Hua  , Feng Ya-Yang  , Xue Yuan  , Lu Jing-Xiao  ,   Key Laboratory of Materials Physics of Ministry of Education, School of Physical Engineering, Zhengzhou University, Zhengzhou 450052, China
Published: December 2020

Two series of silicon films on c-Si substrates with different thicknesses are deposited by radio frequency plasma enhanced chemical vapor deposition (rf-PECVD). The structures of samples are investigated by spectroscopic ellipsometry (SE) with fixed angle. The results show that the films are all amorphous for the first series of samples. In such a case an abrupt a-Si:H/c-Si heterojunction is formed which is beneficial for the passivation of the interface of HIT solar cell. For amorphous silicon films, the fitting result is acceptable by using Tauc-Lorentz Genosc model. For the second series, the films are of epitaxial Si at the initial deposition stages, the amorphous fraction increases with the increase of thickness. When the film thickness reaches a critical value of 46 nm, a transition to pure amorphous phase occurs. The epitaxial film shows excellent fitting by using the effective medium approximation (EMA) model under the assumption of the mixture of c-Si phases and a-Si:H. However, we obtain better fitting result by using a three-layer model, whose bulk layer is divided into EMA layer and a-Si layer after the transition to pure amorphous phase. This study indicates that the SE analysis, operated in different models, is effective to characterize different structures of silicon films on c-Si substrate.
Influence of fluorination time on surface charge accumulation on epoxy resin insulation
Authors: Liu Ya-Qiang  , An Zhen-Lian  , Cang Jun  , Zhang Ye-Wen  , Zheng Fei-Hu  ,   Ministry of Education Key Laboratory of Advanced Microstructure Materials, Department of Physics, Tongji University, Shanghai 200092, China;,   State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

In order to suppress surface charge accumulation on the epoxy resin insulation and to investigate the influence of treatment time on the charge accumulation, epoxy samples are surface fluorinated for the different times of 10 min, 30 min and 60 min in a laboratory vessel using an F2/N2 mixture. Attenuated total reflection infrared analyses and the observations of the cross section and the surface of the samples by SEM indicate the increases in degree of fluorination, thickness and compactness of the fluorinated layer, and the decrease in surface roughness, with treatment time increasing. Compared with the deep surface charge traps and stable surface charge of the unfluorinated (original) sample, as indicated by the open-circuit thermally stimulated discharge current measurement, the fluorinated surface cannot store the charge. The corona charges deposited on the sample surfaces fluorinated for 10 min, 30 min or 60 min rapidly decay to zero in about 2 min, 10 min or 15 mi at room temperature respectively, showing a slowed-down release of charge with fluorination time. The measurements of surface conductivity and contact angle and the calculation of surface energy reveal that fluorination gives rise to dramatic increases in surface conductivity, surface wettability and polarity, while they decrease with treatment time. The significant increase in surface conductivity of the fluorinated sample is attributed to a very likely substantial decrease in trap depth and the adsorbed water on the fluorinated surfac. Surface charging current measurements further show that large steady state current flows along the fluorinated surface during corona charging, in comparison with the almost zero steady state current for the original sample. This implies that the fluorinated sample has much lower surface charge accumulation in the period of charging, than the original sample.
The influence of spatiotemporal modulation on spiral tip dynamics in excitable medium and its application for spiral control
Authors: Qian Yu  ,   Nonlinear Research Institute, Baoji University of Arts and Sciences, Baoji 721000, China
Published: December 2020

In this paper, the influence of spatiotemporal modulation on tip dynamics of periodic spiral wave in excitable medium is studied first. By varying spatiotemporal modulation item, the dynamics of spiral wave changes dramatically and the system undergoes periodic spiral wave, epicycloid meandering spiral wave, traveling spiral wave and hypocycloid meandering spiral wave. An order parameter is introduced to detect the critical conditions of non-equilibrium transition between different patterns. And the variation of spiral tip radius induced by spatiotemporal modulation can also be reflected by this order parameter. When spatiotemporal modulation increases to a critical value, spiral waves break up. And spiral waves will damp to homogeneous rest state if spatiotemporal modulation increases further. The mechanisms of spiral breakup and damping are explained in the paper. Finally we apply the spatiotemporal modulation method to the meandering spiral waves and can successfully control meandering spiral waves into periodic spiral waves or homogeneous rest state.
Effect of thunderstorm electric field on intensity of cosmic ray muons
Authors: Wang Jun-Fang  , Qie Xiu-Shu  , Lu Hong  , Zhang Ji-Long  , Yu Xiao-Xia  , Shi Feng  ,   Key Laboratory of Middle Atmosphere and Global Environment observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;,   Key laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China;,   Graduate School, Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Neutron monitor (NM) in Yangbajing Cosmic Ray Observatory mainly detects nucleus components with energy in a range of 500 MeV20 GeV and a small number of negative muons. On the basis of synchronous data of neutron monitor and atmospheric electric field during 62 thunderstorms from 2008 to 2010, obvious changes of NM counting rate during 27 thunderstorms with significance greater than S5 are found, and among them, 13 cases with significance greater than S10 . A coincident approximate change trend is found between counting rate change percentage and atmospheric electric field amplitude for 13 cases with significance S10 . However no obvious coincident change trend is found for 14 cases with significance 5 S10 . Obvious changes of counting rate do not occur when thunderstorm is just over electric field mill, however obvious changes occur when electric field mill is not exactly below thunderclouds but in the control of bottom positive charge layer. Dorman put forward the theory that NM counting rate changes are correlated with the atmospheric electric field, thus they attributed the former to the acceleration of the electric field to negative muons inside thunderstorms. However, there is found no evident correlation between NM counting rate charge and the atmospheric electric field in this paper, so our experiment does not support Dormanetal's theory.
Quantum process neural networks model algorithm and applications
Authors: Li Pan-Chi  , Wang Hai-Ying  , Dai Qing  , Xiao Hong  ,   School of Computer and Information Technology, Northeast Petroleum University, Daqing 163318, China
Published: December 2020

To enhance the approximation and generalization ability of process neural networks (PNNs), by studying the quantum implementation mechanism of information processing of process neuron, a new idea of designing quantum process neuron is proposed in this paper, based on the quantum rotation gates and the quantum controlled-non gates. In the proposed approach, the discrete process inputs are expressed by the qubits, which, as the control qubits of controlled-non gates after being rotated by the quantum rotation gates, control the target qubits to reverse. The model outputs are described by the probability amplitude of state |1 in the target qubits. Then the quantum process neural networks (QPNNs) are designed by the quantum process neurons for the hidden layer and the normal neurons for the output layer. The algorithm of QPNN is derived through the quantum computing. The proposed approach is utilized to predict the smoothed yearly mean sunspot numbers, and the results indicate that the QPNN has higher prediction accuracy than the normal PNN, thus it has a certain theoretical meaning and practical value for the complex prediction.
Effect of the Stark shift on entanglement in a double Jaynes-Cummings model in thermal environment
Authors: Hu Yao-Hua  ,   Physics and Electronic Information College, Luoyang Normal University, Luoyang 471022, China
Published: December 2020

Considering a double two-photon Jaynes-Cummings (J-C) model, we study the effects of Stark shift and mean photon number on entanglement between two two-level atoms when the atoms are initially in a maximally entangled state and the fields are in the single-mode thermal fields. The results show that the two atoms evolve periodically into a disentangled separable state when Stark shift is not considered. However, in the presence of Stark shift, the two two-level atoms are no longer disentangled and long-lived entanglement can be obtained. For a larger value of the Stark shift parameter and a smaller mean photon number, the two atoms can remain in a stationary entangled state. These properties show that the Stark shift can be used to control entanglement in the double two-photon J-C model under the influence of thermal environment.
Characterization of gravitational waves from spinning compact binaries
Authors: Wang Yu-Zhao  , Wu Xin  , Zhong Shuang-Ying  ,   Department of Physics, Nanchang University, Nanchang 330031, China
Published: December 2020

Some characterizations of gravitational waves emitted from the 2.5 post-Newtonian order Lagrangian dynamics of spinning compact binaries including the next-order spin-orbit contribution and the radiative reaction are detailed. The relationship between the regular and chaotic dynamics and the gravitational waveforms is also described. When the radiative reaction term does not appear in the equations of motion, the gravitational waves are periodic/quasi-periodic for an order conservative binary system, but they seem to be typically irregular for a chaotic one. On the other hand, the binary systems become dissipative and should coalesce if the radiative reaction term is added to the equations of motion. In the dissipative case, the original ordered conservative system can still give regular gravitational waveforms in such a long time before the occurrence of the merging orbits. However, the coalescence time of the binary system corresponding to its original chaotic conservative system is too short to obtain enough information about the characterization of the gravitational waveforms.
Simulation study on the stochastic resonance of single-mode laser system
Authors: Yang Ming  , Li Xiang-Lian  , Wu Da-Jin  ,   School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

Single-mode laser systems with modulated signals are studied by the method of numerical simulation. The signal-to-noise ratio, the output signal power, and the background noise power are analyzed near and far from the threshold. It is found that when the laser works near the threshold, the signal-to-noise ratio is present and the behavior of stochastic resonance takes place as the quantum noise increases, no matter whether the quantum noise is correlated with the pump noise. The correlation between the two noises, however, will increase the signal-to-noise ratio. And when the laser works far from the threshold, only when the two noises are correlated can the behavior of stochastic resonance appear. It is also found that the output signal power can be influenced by the noises. What is more, the simulation results are compared with those obtained by the method of linear approximation.
Stability analysis of equivalent series resistance of output capacitor in fixed off-time controlled Buck converter
Authors: Zhang Xi  , Bao Bo-Cheng  , Wang Jin-Ping  , Ma Zheng-Hua  , Xu Jian-Ping  ,   School of Information Science and Engineering, Changzhou University, Changzhou 213164, China;,   School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

Based on the power simulation software, the reason of the output voltage phase lagging behind the inductor current phase is analyzed qualitatively, and the mechanism to cause the pulse bursting phenomenon in fixed-off-time (FOT) controlled Buck converter is explained. The way to choose the equivalent series resistance (ESR) of output capacitor to eliminate these complex nonlinear phenomena is discussed. The critical ESR to ensure the state operation of FOT controlled Buck converter is obtained. The study results indicate that the ESR has a great effect on the operation state of FOT controlled Buck converter. When the ESR is smaller than the critical value, the output voltage phase lags behind the inductor current phase, resulting in the pulse bursting phenomenon; while when the ESR is larger than the critical value, the output voltage variation keeps in phase with the inductor current variation, the pulse bursting phenomenon disappearing. In addition, the describing function method is used to obtain the transfer function from the reference voltage to the output voltage. By using the Routh-Hurwitz criterion, it is indicated that the critical ESR is the condition of destabilizing FOT controlled Buck converter.
Frequency enhancement and control of chaos in two spatial coupled semiconductor lasers using external light injection
Authors: Yan Sen-Lin  ,   School of Physics and Electronic Engineering, Nanjing Xiaozhuang University, Nanjing 210017, China
Published: December 2020

We present a novel system of oscillation frequency enhancement and control of chaos in two spatial coupled semiconductor lasers due to external light injection. We study the characteristics of frequency enhancement and control of chaos in the system and give a static frequency detuning formula. We find three regimes of chaotic enhancement when external light is injected into single laser, in which, strong light injection can result effectively in frequency enhancement in the injected laser, but the frequency weakens slowly in the other. And large detuning can result effectively in frequency enhancements in both lasers while the frequency can be enlarged 3.5 times more than the intrinsic frequency of the laser 1. Chaos-control region is found in low injection levels. In this region, lasers can be controlled to single -cycle, dual-cycle, cycle-4, cycle-6 and other quasi-cycles. When the dual-injection is present, strong light injection or large detuning can result effectively in frequency enhancements in both lasers while the frequency can be enlarged 3.5 or 2.65 times more than the intrinsic frequency of the laser 1 or 2. Chaos-control region is also found in large injection levels. In this region, both lasers can be controlled to single-cycle, cycle-3, cycle-6 and other quasi-cycles. We point out in detail a path from single-cycle to quasi-cycle to frequency enhancement of chaos when the single-injection is present. We find another reverse path from chaos to quasi-cycle to single-cycle when the dual-injection is present.
Analysis of the stability and solitary waves for multi-velocity difference car-following model of traffic flow
Authors: Yuan Na  , Hua Cun-Cai  ,   School of Mathematics, Yunnan Normal University, Kunming 650092, China
Published: December 2020

This article deals with the characteristic of the multiple velocity difference car-following model. We obtain the stability conditions of the model by using the linear stability analysis, and find that the stable region is apparently enlarged by adjusting the information about the multi-velocity difference. We study the nonlinear characteristics of the model by applying the reductive perturbation method. We obtain the Burgers equation and the modified Korteweg-de-Vries (mKdV) equation around the critical point and the Korteweg-de-Vries (KdV) equation near the neutral stability line in the stable region and the unstable region and the metastable region. The soliton solution of Burgers equation, the kink-antikink solution of mKdV equation, and the solition solution of KdV equation describe the traffic jams.