bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Ni4PrB electronic structure and magnetism
Authors: Yi Yong  , Li Kai  , Ding Zhi-Jie  , Yi Zao  , Luo Jiang-Shan  , Tang Yong-Jian  ,   Research Center of Laser Fusion of CAEP, Mianyang 621900, China;,   State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Mianyang 621010, China
Published: December 2020

Considering the Coulomb potential and the exchange action, electronic structure, band structure and magnetic properties of the compound Ni4PrB within the local spin-density approximation (LSDA) and the LSDA+U approximation are studied through numerical simulation. The simulation results show that this system is a metallic semi-conductor and has Pr-Ni ferromagnetic coupling. The added Coulomb U effect can strongly affect magnetic properties and stable structure, and the total magnetic moment is provided by the local Ni magnetic moment before adding U effect, when the U effect is added to the system, the total magnetic moment is provided by the local Pr magnetic moment, and the system has a high structure stability. So U effect affects strongly the strong correlation, then it can describe reasonably the strong correlation and the exclusion effect caused by the spin exclusion.
First-principles calculations of structure and magnetic properties of -Fe(Si)phase precipitated in the Finemet alloy
Authors: Hu Yu-Ping  , Ping Kai-Bin  , Yan Zhi-Jie  , Yang Wen  , Gong Chang-Wei  ,   School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China
Published: December 2020

The structure and the magnetic properties of -Fe(Si) phase precipitated in the Finemet alloy, and some factors influencing the magnetic properties of -Fe(Si) phase are investigated by first-principles calculation based on the density functional theory. From the angle of electron spin, the magnetic properties of -Fe(Si) phases with different solubilityies of Si located at the different sites of the -Fe superlattice are investigated. The calculation results show that the spin-state density is a critical factor influencing the magnetic properties. It is found that -Fe(Si) phase with Si at the vertex sites shows better magnetic properties than those with Si at the core sites. It is concluded that with the solubility of Si in the -Fe(Si) phase increasing, the probability of Si occurring at the vertex sites increases, which results in better magnetic properties. The calculation results accord with the previous experimental results. The present work is helpful for understanding the magnetism of the Finemet alloy.
Research on quantum efficient fitting and structure of high performance transmission-mode GaAs photocathode
Authors: Zhao Jing  , Zhang Yi-Jun  , Chang Ben-Kang  , Xiong Ya-Juan  , Zhang Jun-Ju  , Shi Feng  , Cheng Hong-Chang  , Cui Dong-Xu  ,   Institute of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science & Technology, Nanjing 210094, China;,   Key Laboratory of Low Light Level Technology of COSTIND, Xi'an 710065, China;,   Xi'an Institute of Applied Optics, Xi'an 710065, China
Published: December 2020

To explore the structural feature of high performance transmission-mode GaAs photocathode, the optical properties and shortwave limitation for the transmission-mode quantum efficient formula is modified. By using the modified formula, a high quantum efficient (43%) curve of ITT is well fitted. A series of structural parameters is obtained with in a relative error less than 5%, which indicates that the thickness of the Ga1-xAlxAs window layer is 0.30.5 m, the Al mole value is 0.7, and the thickness of the GaAs active layer is 1.11.4 m. In addition, an optimized structure for the uniform-doping transmission-mode GaAs photocathode is suggested based on the fitted results. When the thickness of the Ga1-xAlxAs (x=0.7) layer and the GaAs layer are 0.4 m and 1.11.5 m respectively, the integral sensitivity can exceed 2350 A/lm.
A new research on sea surface wind direction retrieval of synthetic aperture radar image
Authors: Jiang Zhu-Hui  , Huang Si-Xun  , Shi Han-Qing  , Zhang Wei  , Wang Biao  ,   Institute of Meteorology, People’s Liberation Army University of Science and Technology, Nanjing 211101, China
Published: December 2020

A new method to retrieve sea surface wind direction using synthetic aperture radar image is presented. Some pretreatment steps such as suppressing noise, down sampling and dividing into several sub-images are presented first. The method of two-dimensional numerical differentiation based on Tikhonov regularization is introduced to compute the gradient direction in the sub-image intensity of every point. The distance weighted objective function is used to compute the overall gradient direction in the sub-images. The retrieved wind direction is orthogonal to the overall gradient. When adding 10% of random errors, numerical simulations show that the result of numerical differentiation is better than that from the Sobel operator which is based on the finite difference method: the former error is 0.7293 , and the latter error is 13.5069 . Finally, an experiment based on real SAR data shows that the wind direction deviates from the overall direction determined by the method of Sobel operator, and the direction determined by the method of numerical differentiation is consistent well with the overall wind direction. Comparing the ship board wind direction and the corresponding location wind direction retrieved from the synthetic aperture radar sub-images with the two methods, the average result error of Sobel operator method is 9.0331, while that of numerical differentiation method is 1.1148. This new method is an effective and high accurate method to retrieve the sea surface wind direction of synthetic aperture radar image.
Superparamagnetic nanoparticles formed in Fe-implanted ZnO
Authors: Pan Feng  , Ding Bin-Feng  , Fa Tao  , Cheng Feng-Feng  , Zhou Sheng-Qiang  , Yao Shu-De  ,   State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China;,   Department of Physics, Shaanxi University of Technology, Hanzhong 723001, China;,   Department of Physics and Electronic Information, Langfang Teachers College, Langfang 065000, China
Published: December 2020

Due to its potential application to diluted magnetic oxides, transition metal doped ZnO has been under intensive investigation. We present a correlation between the structural and the magnetic properties of Fe implanted ZnO bulk crystals. Crystalline damage recovery, structural and magnetic properties are studied by Rutherford backscattering spectrometry and channelling (RBS/C), synchrotron radiation X-ray diffraction (SR-XRD), and superconducting quantum interference device magnetometer (SQUID), respectively. The 623 K Fe ion implantation and the high vacuum annealing at 823 K lead to the formation of secondary phase -Fe and -Fe nanoparticles. The discrepancy between the zero-field cooling and the field cooling curves further indicates that Fe-implanted ZnO is superparamagnetic and the observed ferromagnetism originates from the Fe nanoparticles.
Design and preparation of a radar-absorbing material based on metamaterial
Authors: Sun Liang-Kui  , Cheng Hai-Feng  , Zhou Yong-Jiang  , Wang Jun  , Pang Yong-Qiang  ,   Key Laboratory of Advanced CeramicFibers and Composites, College of Aerospace and Materials Engineering, National University of Defence Technology, Changsha 410073, China
Published: December 2020

A kind of radar-absorbing material (RAM) based on metamaterial, which contains resistive patches, dielectric substrate and metal backing, is designed. The reflectivity of the RAM is calculated using the finite difference time-domain method (FDTD) and optimized by genetic algorithm(GA). Then RAMs with a reflectivity bandwidth of 818 GHz below -10 dB is obtained. Moreover, its thickness is only 3mm. To confirm the design results, the RAM is prepared by fabricating a hollow quartz fibre reinforced epoxy resin substrate through using hand lay-up process and making the resistive patches by screen painting. The reflectivity of the absorber is measured, showing that the experimental result is consistent with the design value.
Hawking radiation of dynamical Kinnersley black hole under the new tortoise coordinate transformation
Authors: Pan Wei-Zhen  , Yang Xue-Jun  , Luo Jin-Cai  ,   Department of Physics and Electronic Information, Shaoxing University, Shaoxing 312000, China
Published: December 2020

With two new tortoise coordinate transformations, Hawking effect from a dynamical Kinnersley black hole is investigated by using the improved Damour-Ruffini method. After the tortoise coordinate transformation, the Klein-Gordon equation can be written in the standard form at the event horizon. Then extending the outgoing wave from outside to inside of the horizon analytically, the surface gravity and the Hawking temperature can be obtained automatically. It is found that Hawking temperature of different points on the surface are different. There is a problem of dimension in the usual tortoise coordinate and the results are different from those of the same black hole by using two different tortoise coordinate transformations. The results obtained by using two new tortoise coordinate transformations are still different.
New explicit exact solution of one type of the sine-Gordon equation with self-consistent source
Authors: Su Jun  , Xu Wei  , Duan Dong-Hai  , Xu Gen-Jiu  ,   School of Science, Northwestern Polytechnical University, Xi'an 710072, China;,   School of Mathematics and Information Science, Weinan Teacher's University, Weinan 714000, China
Published: December 2020

This paper deals with one type of sine-Gordon with self-consistent source (SGESCS). The explicit exact solution of the equation is investigated using a generalized binary Darboux transformation. The complexiton solution for the equation is finally obtained.
Asymptotic solution for fractal soliton of disturbed Nizhnik-Novikov-Veselov system
Authors: Shi Lan-Fang  , Zhou Xian-Chun  , Mo Jia-Qi  ,   College of Mathematics and Physics, Nanjing University of Information Science and Technology, Nanjing 210044, China;,   College of Science, Hohai University, Nanjing 210098, China;,   College of Electronic and Information Engineering, Jiangsu Technology and Engineering Center for Meteorological Senor Network, Nanjing University of Information Science and Technology, Nanjing 210044, China;,   Department of Mathematics, Anhui Normal University, Wuhu 241003, China
Published: December 2020

A class of nonlinear disturbed Nizhnik-Novikov-Veselov system is studied. Using the special asymptotic method, the asymptotic solution for fractal soliton of corresponding system is obtained.
Numerical simulation of negative oxygen ion generation and temporal evolution in atmospheric plasma
Authors: Ouyang Jian-Ming  , Shao Fu-Qiu  , Zou De-Bin  ,   National University of Defense Technology, Changsha 410073, China
Published: December 2020

The generation process and temporal evolution of negative oxygen ions in a atmospheric plasma are numerically simulated in this paper. The results show that there exists a knee point in the attenuation process of negative oxygen ions, followed by a long time stationary phase. The density of negative oxygen ions in the stationary phase has a linear relation with the initial electron number density. Moisture content has a large effect on the temporal evolution of negative oxygen ions.
Entanglement and nonlocality for generalized Greenberger-Horne-Zeilinger state
Authors: Wang Xiao-Qin  , Lu Huai-Xin  , Zhao Jia-Qiang  ,   Department of Physics and Electronic Sciences, Weifang University, Weifang 261061, China
Published: December 2020

With the help of Svetlichny's inequality, we obtain an analytical expression of the quantum nonlocality for generalized Greenberger-Horne-Zeilinger(GHZ) state composed of a (GHZ) state and a W state. The numerical results between tripartite entanglement and nonlocality for generalized GHZ state are discussed.
Control of chaos solely based on PSO-LSSVM without usiing an analytical model
Authors: Long Wen  , Jiao Jian-Jun  , Long Zu-Qiang  ,   Guizhou Key Laboratory of Economics System Simulation, Guizhou College of Finance and Economics, Guiyang 550004, China;,   Department of Physics and Electronics Information Science, Hengyang Normal College, Hengyang 421008, China
Published: December 2020

For a chaotic system with nonlinear ity and uncertainty, it is difficult to obtain the satisfactory performance using general control methods. A least square support vector marchine (LSSVM) control method based on particle swarm optimigation(PSO), is proposed for chaos control. Optimizing two parameters of LSSVM model by PSO abilities of the fast convergence and whole optimization, thus aroiding the blindness of man-made choice, the LSSVM-PSO model can enhance the capability of forecasting. The proposed method does not need any analytic model, and it is still effective in the presence of measurement noises. Simulation results with a Logistic mapping and Henon attractor show the effectiveness and feasibility of this method.
Image scrambling based on Logistic uniform distribution
Authors: Cao Guang-Hui  , Hu Kai  , Tong Wei  ,   School of Computer Science and Technology, Beijing University of Aeronautics and Astronautics, Beijing 100191, China;,   Electronic & Information Engineering College, Liaoning University of Technology, Jinzhou 121001, China;,   Department of Computer Science and Engineering, Michigan State University, East Lansing, Michigan 48823, USA
Published: December 2020

Most algorithms of image scrambling transformation based on Logistic map are currently dedicated to permutation rules and methods without considering design philosophy. In this paper, we propose a new image bit permutation algorithm based on the Logistic map. This algorithm with firmly mathematic theory is designed by following the scientific course from theory to practice. According to the characteristics of chaotic sensitivity to initial condition and large key space, starting from Logistic map, the transformation which can generate uniformly distributed random variable in the interval based on Logistic at =4 is developed. Utilizing this generated uniform random variable, random permutation algorithm based on interchange position is obtained. For measuring permutation strength of the proposed random permutation algorithm, the corresponding permutation strength testing algorithm is designed. Based on this permutation algorithm, the image bit permutation algorithm is described. When used to image and compared with Baker Ye and Yoon algorithm, the proposed image bit permutation method exhibits large key space, extreme sensitivity to initial condition, effective capability for dissipating high correlation among pixels and increasing information about entropy value. Results show that this proposed scrambling scheme with firmly theoretical foundation can enhance image security significantly.
Unified projective synchronization of chaotic system
Authors: Li Nong  , Li Jian-Fen  ,   Engineering Institute,Air Force Engineering University, Xi’an 710038, China;,   Science Institute,Air Force Engineering University, Xi’an 710051, China
Published: December 2020

A unified method for the projective synchronization of chaotic system is proposed in this paper. The universal model of chaotic projective synchronization is established by constructing a generalized proportion matrix and an appropriate response system. All kinds of synchronized schemes can be achieved by varying the generalized proportion matrix, including generalized projective synchronization, dislocated projective synchronization and generalized hybrid dislocated projective synchronization and so on. The stability analysis in the paper is proved using Lyapunov stability theory. Numerical simulations of generalized hybrid dislocated projective synchronization for multiscroll chaotic attractors system and hyperchaotic Qi system verify the effectiveness of the proposed method.
Image fusion algorithm based on block-DCT in wavelet domain
Authors: Gan Tian  , Feng Shao-Tong  , Nie Shou-Ping  , Zhu Zhu-Qing  ,   Jiangsu Province Key Laboratory for Opto-electronic Technology Nanjing Normal University, Nanjing 210097, China
Published: December 2020

A feature-level image fusion algorithm using wavelet transform combined with the discrete cosine transform (DCT) is proposed. The basic idea is to perform block-DCT of each source image first, and then to select the retained coefficients according to maximum variance; each image is compressed to 25 percent of the original size. The coordinates of the retained coefficients are used as private keys. Finally, the processed DCT coefficient matrixes are taken as the wavelet coefficients and the fused image is obtained by taking the inverse wavelet transform. The experimental results show that the algorithm realizes the fusion of images with different sizes. Furthermore, one single image can be reconstructed by one single private key.
Hot-images induced by the random distribution defects in high power laser systems
Authors: Cai Zhao-Bin  , Zhao Jian-Lin  , Peng Tao  , Li Dong  ,   Shaanxi Key Laboratory of Optical Information Technology, Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education , School of Science, Northwestern Polytechnical University, Xi’ an 710072, China
Published: December 2020

Based on the diffraction theory model of hot-images, the formation mechanism of the hot-images induced by the defects with random size and position distribution in a high power laser system is theoretically investigated by using the propagation matrix of the spatial spectrum. For the comparison with the theoretical results, the evolution of the hot-images induced by defects with random distribution is also numerically investigated. Furthermore, the relationship describing the tendency of the hot-image intensity with the number or size range of the defects is analyzed by employing statistical theory. The results show that the hot-image intensity will reach a maximum if the size of the corresponding defect approaches a specific value, and that there exists a corresponding relation between the transverse position of the hot-image point with the maximum intensity and the defect distribution. It is also found that the intensity of the hot-image has an upward trend with both the size range and the number of defects within a certain scope increasing. However, the tendency will be steady when the probability of the defects with the most risk of damage size reaches a certain value. Such results maybe provide a guidance for improving cleanliness of the optical components.
Design of dispersion decreasing fiber for compressing stationary rescaled pulse
Authors: Zhang Yu-Long  , Zhang Ai-Ling  ,   School of Computer and Communication Engineering, Key lab of Film Electronics and Communication Devices of Tianjin, Communication Devices and Technology Engineering Research Center of EMC, Tianjin University of Technology, Tianjin 300384, China
Published: December 2020

A ccording to the compression principle of stationary rescaled pulse (SRP) in the comb-like optical fiber (CPF), the design of dispersion decreasing fiber (DDF) for compressing stationary rescaled pulse is demonstrated in this paper. The dispersion profile of DDF is found to be decreased linearly. The compression ratio and the power ratio are both equal to the ratio between initial and final values of second order dispersion coefficient when the incident pulse is SRP. When the dispersion slope of the fiber is small enough, the fundamental soliton without chirp can be approximated as SRP. When the dispersion slope of the fiber is high, the fundamental soliton without chirp cannot be approximated as SRP. When the incident pulse is fundamental soliton with linear chirp, which is proportional to the dispersion slope of the fiber, the compression ratio and the power ratio are closer to the ratio between initial and final dispersion values,which indicates that the fundamental soliton with linear chirp is approximated as SRP with less error than fundamental soliton without chirp.
Diffraction property of broadband metal multi-layer dielectric gratings based on rigorous coupled-wave analysis
Authors: Kong Wei-Jin  , Wang Shu-Hao  , Wei Shi-Jie  , Yun Mao-Jin  , Zhang Wen-Fei  , Wang Xin-Jie  , Zhang Meng-Meng  ,   College of Physics Science, Qingdao University,Qingdao 266071, China
Published: December 2020

The rigorous coupled-wave analysis technique for describing the diffraction of metal multi-layer diffraction grating (MMDG) is built. Formulation for a stable and efficient numerical implementation of diffraction efficiency is presented for MMDG with TE polarization. With the merit function of the -1 order diffraction efficiency higher than 97% and working bandwidth, the parameters of MMDG are optimized to achieve broadband. The bandwidths used for 800 nm and 1053 nm can be 130 nm and 150 nm respectively. The manufacture latitude and the effective incident angle for the optimized structure of MMDG are discussed. The optimized grating should be useful for chirped pulse compress.
Threshold value of shear stress in H-22 cells generated sonoporation
Authors: Mo Run-Yang  , Lin Shu-Yu  , Wang Cheng-Hui  ,   Shaanxi Key Laboratory of Ultrasonic, College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China
Published: December 2020

Based on a spherically symmetric bubble model, the threshold shear stress for H-22 cells which are irradiated by continuous focused ultrasound is estimated. On the condition that the final concentration of the superparamagnetic iron oxide (SPIO) in the cell suspension is 410 g/mL, the focused ultrasound sonication is at a frequency of 1.37 MHz, the power from amplifer is 2 W, and H-22 cells are exposed to the ultrasound for 60 s, the labeling efficiency is about 45.9%13.5%. Prussian blue staining confirms iron uptake and shows numerous blue-stained iron particles in the cytoplasm, while more than 90% labeled cells remained viable. The results show that the reparable sonoporation arises in plasma membrane and SPIO nanoparticles enter into the H-22 cells. Numerical calculations show that the shear stress acting on the cell is 697 Pa, which is the threshold shear stress for H-22 cell sonoporation.
Influence of reduced electric field on the evolvement characteristics of plasma under conditions of N2/O2 discharge
Authors: Du Hong-Liang  , He Li-Ming  , Lan Yu-Dan  , Wang Feng  ,   Department of Aerocraft and Propulsion, Engineering Institute of Air Force Engineering University, Xi’an 710038, China
Published: December 2020

Adopting the plasma kinetic model, we perform a numerical calculation of evolution characteristics in N2/O2 plasma with various reduced electric fields. The results show that there is an approximate linear relation between electron average energy and reduced electric field, the electron average energy is 2.6 eV and its maximum is 35 eV when reduced electric field is 100 Td, and reduced electric field has a strong influence on electron energy distributing function. The number densities of nitrogen molecules and atoms, oxygen atoms in electronic excited state reach their peaks when discharge is over, then drop off; but the number density of nitrogen molecules in vibrational excitation remains unchanged after discharge; oxygen atoms recombine into ozone molecules. With the increase of reduced electric field, the number density of vibration excitated nitrogen molecules reduces because of the decrease of the number of electrons with low energy, but other particles are increasing. The number densities of vibrational excitated nitrogen molecules are 3.831011cm-3, 1.981011cm-3 and 1.771011 cm-3 when reduced electric fields are set to be 50 Td, 75 Td and 100 Td respectively.
Cluster-plus-glue-atom model in bcc solid solution alloys
Authors: Hao Chuan-Pu  , Wang Qing  , Ma Ren-Tao  , Wang Ying-Min  , Qiang Jian-Bing  , Dong Chuang  ,   Key Laboratory of Materials Modification, Dalian University of Technology, Ministry of Education, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
Published: December 2020

In the present work we propose the cluster-plus-glue-atom model for bcc solid solutions by establishing periodic packing geometries of CN14 basic clusters in bcc lattice to reflect the idealized chemical short-range order near solute atoms. The model is expressed by cluster formula (glue)x, where the cluster center is occupied by a solute having the largest negative enthalpy, mixed with the solvent, and other solute atoms serves as glues or substitute for the solvents in cluster shell. The 1 ∶1 cluster model (glue atom)1 is specially emphasized that guarantees to a maximum extent the glue-cluster nearest neighbors and hence forms a most efficient configuration. This 1 ∶1 model is conducible to the design of a low-V hydrogen-storage V1 alloy and a Nb1 alloy with low Youngs modulus combined with high strength.
Total ionizing dose effect of 0.18 m nMOSFETs
Authors: Liu Zhang-Li  , Hu Zhi-Yuan  , Zhang Zheng-Xuan  , Shao Hua  , Ning Bing-Xu  , Bi Da-Wei  , Chen Ming  , Zou Shi-Chang  ,   The State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China;,   Graduate University of the Chinese Academy of Sciences, Beijing 100039, China
Published: December 2020

A 0.18 m MOSFET with shallow trench isolation is exposed to a -ray radiation. The parameters such as off-state leakage current, threshold voltage, transconductance, gate leakage current, and subthreshold slope are analyzed for pre- and post-irradiation. By introducing constant sheet charges at the shallow trench isolation oxide sidewall, good agreement between 3D simulation and experiment result is demonstrated. We believe that the thin gate oxide is insensitive to radiation, and the radiation induced charge trapping in the shallow trench isolation still leads to macroscopic effects such as drain-to-source leakage current, ultimately limiting the tolerance of CMOS circuits.
A study of CuPc-doping MEH-PPV/PCBM organic photovoltaic devices
Authors: Chen Wei-Bing  , Yang Wei-Feng  , Zou Hao-Jie  , Tang Jian-Xing  , Deng Lin-Feng  , Li Pei-Tao  ,   School of Computer and Communication, Hunan University of Technology, Zhuzhou 412008, China;,   Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hongkong SAR, China
Published: December 2020

We fabricate efficient bulk heterojunction organic photovoltaic (OPV) device based on poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), with copper(Ⅱ) phthalocyanine (CuPc) used as a donor and -phenyl C61-butyric acid methyl ester (PCBM) serving as an acceptor. The power conversion efficiency of the MEH-PPV/PCBM OPV device with 15% CuPc (1.41%) increases by 12% compared with that of the standard MEH-PPV/PCBM device (1.26%). The efficiency improvement can be attributed to the CuPc supplemental absorption and higher mobility than MEH-PPV, leading to increased short-circuit current density.
The origin of EPIR effect in Nd0.7Sr0.3MnO3 ceramics
Authors: Yang Chang-Ping  , Chen Shun-Sheng  , Dai Qi  , Song Xue-Ping  ,   Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062, China;,   State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
Published: December 2020

Polycrystalline ceramic Nd0.7Sr0.3MnO3 is synthesized using high-energy ball milling and post heat treatment method. The properties of electric transport are measured using direct current (DC) 4-wire and 2-wire methods. The results show that both the grain (phase) boundary and the electrode-bulk contact interface has interfacial resistance and space charge layer. The two kinds of space charge regions have greatly different effects on the DC transport: for the former, the I-V curve exhibits nonlinear characteristic and no EPIR effect takes place; for the later, however, an obvious EPIR effect is observed even if the I-V curve also shows nonlinear behaviour. It well suggests that for the ceramic Nd0.7Sr0.3MnO3, only the electrode-bulk contact interface can induce the EPIR effect although there is a similar nonlinear I-V characteristic for the grain (phase) boundary and the electrode-bulk contact interface.
Electrical and optical properties of Cu-Al-O thin films sputtered using non-stoichiometric target
Authors: Pan Jia-Qi  , Zhu Chen-Quan  , Li Yu-Ren  , Lan Wei  , Su Qing  , Liu Xue-Qin  , Xie Er-Qing  ,   School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China;,   Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China
Published: December 2020

Taking account difference in sputtering rate between Cu and Al, we use a polycrystalline CuAlO2 target with a ratio between Cu and Al being 0.9 ∶1 to prepare the Cu-Al-O film by RF magnetron sputtering. The electrical and the optical properties of the thin film are influenced by the temperature of the substrate. When the substrate temperature is around 500 ℃, the film has a good transmission of 70% in the range of the visible light. Calculated by the fitted formula, the direct band gap is 3.52 eV,and it is in good agreement with the theoretical value. Near room temperature, the thin film conforms to the semiconductor thermal activation mechanism, when the substrate temperature is about 500 ℃, the film conductivity reaches 2.4810-3 Scm-1.
Effects of interfacial Ru, Pd, Ag, and Au insertion layers on the anisotropic magnetoresistance in Ta/NiFe/Ta trilayers
Authors: Xu Yong  , Cai Jian-Wang  ,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

Ta/NiFe/Ta trilayers are commonly used in various commercial sensors based on anisotropic magnetoresistive(AMR) effect. Technologically it is desirable to reduce NiFe film thickness to diminish the demagnetization effect for the smaller and smaller devices. However, the AMR ratio of thin NiFe film decreases rapidly with film thickness decreasing when the NiFe film is thinner than 20 nm. Our previous work revealed that the AMR ratio and the thermal stability of Ta/NiFe/Ta trilayers can be significantly improved through interfacial Pt addition due to the enhanced interfacial spin-orbit scattering and the suppressed magnetic dead layers. In this paper, 4d and 5d elements including Ru, Pd, Ag and Au, are also introduced at the interfaces of Ta/NiFe/Ta films fabricated by DC magnetron sputtering. It is found that the insertion of interfacial Pd layers leads to an appreciable AMR enhancement in the as-sputtered state and after annealing. Insertion layers of Ag and Au with small surface energy and relatively low melting point suffer from thermal interdiffusion and seriously deteriorate the AMR of the annealed films, whereas Ru insertion layers exhibit improved thermal stability. The present results indicate that the AMR of Ta/NiFe/Ta films can be notably affected by the extremely thin interfacial insertion layers due to the changed interfacial spin-orbit scattering, magnetic dead layer and atomic interdiffusion.
Electric tunability of microwave permeability dispersion behaviors of metamaterials
Authors: Zhong Shun-Lin  , Han Man-Gui  , Deng Long-Jiang  ,   State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

By embedding a capacity-variable diode into a split ring resonator (SRR), it is found that the effective capacitance of such an SRR element can be varied by the biased voltage of diode. Therefore the resonance frequency and effective permeability of an SRR element can be tuned. Based on these results, a smart microwave magnetic metamaterial is proposed. Employing the finite-difference time-domain and retrieval method, the variations of resonance frequency and permeability of the SRR element are simulated and calculated by changing the biased voltage. It is found that with the decrease of capacitance due to the increase of biased voltage, the resonance frequencies are shifted towards lower values, and so are the resonance frequencies of permeability dispersion. Finally, the difference in permeability dispersion behavior between SRR structure and natural magnetic material (for instance, ferrite) has been pointed out.
Influence of long lifetime absorption process on the measurement of ultrafast carrier dynamics
Authors: Wang Wen-Fang  , Chen Ke  , Wu Jing-Da  , Wen Jin-Hui  , Lai Tian-Shu  ,   State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University,Guangzhou 510275,China
Published: December 2020

The wavelength dependence of ultrafast relaxation dynamics of photoexcited carriers in bulk GaAs is studied using femtosecond time-resolved pump-probe transmission spectroscopy under the same photoexcited carrier concentration and the ratio of pump to probe in intensity. Negative and oscillating time-delayed signals are observed at central wavelengths of 760 nm and 780 nm and judged to be incorrect physically by comparson with a simulated computation result. It is found by waveform analysis that they are caused by the phase reversal of the output waveforms from a photodetector, while the phase reversal originates from a long lifetime absorption process existing in GaAs sample. It is pointed out that the phase reversal of the waveform can be corrected by raising the ratio of pump to probe in intensity at the photodetector, so that right transient traces can be obtained. However, raising the ratio is incompatible with the viewpoint that the scattered contribution to the photodetector from pump light should be filtered as much as possible. This result has an important reference value for the acquisition of correct ultrafast dynamics using time-resolved pump-probe spectroscopy.
Effects of codoping of Al and Sb on structure and optical properties of ZnO nanorod ordered array thin films
Authors: Zhong Wen-Wu  , Liu Fa-Min  , Cai Lu-Gang  , Ding Peng  , Liu Xue-Quan  , Li Yi  ,   Department of Physics, School of Physics and Nuclear Energy Engineering, Key Laboratory of Micro-nano Measurement-Manipulation and Physics, Ministry of Education,Beihang University, Beijing 100191, China;,   Central Iron and Steel Research Institute, Beijing 100081, China
Published: December 2020

An Al and Sb codoped ZnO nanorod ordered array thin film is deposited on a glass substrate with a ZnO seed layer by hydrothermal method. The XRD, SEM, TEM, and SAED results indicate that the thin film consists of nanorods growing in the direction vertical to the ZnO seed layer, and that the nanorods with an average diameter of 27.8 nm and length of 1.02 m consist of single crystalline wurtzite ZnO crystal growing along the [001] direction. Raman scattering analysis demonstrates that the Al and Sb codoped ZnO thin films with the concentrations of Al and Sb of 3.0 at%, 4.0 at%, 5.0 at%, 6.0 at% have Raman shifts of 3, 10, 14 and 12 cm-1 according to Raman shift 580 cm-1 of undoped ZnO nanorod thin film, respectively. Room temperature photoluminescence reveals that the emission intensity decreases at 545 nm and increases at 414 nm in ZnO film prepared by the codoping of Al and Sb. It is because the decrease of Oi and the increase of Zni are caused by the codoping of Al and Sb.
Principles of potential entransy in generalized flow
Authors: Cheng Xue-Tao  , Xu Xiang-Hua  , Liang Xin-Gang  ,   Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
Published: December 2020

Some natural phenomena, such as heat transfer, molecular diffusion and electricity conduction, are very similar to each other to some extent. They all could be treated as generalized flows. Based on this kind of similarity, in this paper we generalize the theory of entransy, and define the concepts of potential entransy, potential entransy flux, and potential entransy dissipation. In the system where there is only one kind of generalized flow or two kinds of generalized flows, the conditions under which we can develop the principles of potential entransy are introduced. Furthermore, the minimum principle of potential entransy loss, the extremum principle of potential entransy dissipation and the generalized minimum flow resistance principle are developed and discussed.
Influence of TiCl4 nanoporous TiO2 films on the performance of dye-sensitized solar cells
Authors: Xi Xiao-Wang  , Hu Lin-Hua  , Xu Wei-Wei  , Dai Song-Yuan  ,   Key Laboratory of Novel Thin Film Solar cells, Institute of Plasma Physics, Chinese Academy of science, Hefei 230031, China;,   The college of Mechanical and Electrical Technology, Wuxi Institute of technology, Wuxi 214121, China;,   Jiangsu Provincial Key Lab of ASIC Design, Nantong University, Nantong 226019, China
Published: December 2020

The mechanisms of electron transport and back-reaction in dye-sensitized solar cells (DSCSs) are investigated by intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS). The DSCSs with and without TiCl4-treated nanoporous TiO2 films are measured by IMPS/IMVS. The results indicate that the electron lifetime (n), the diffusion coefficient (Dn), the diffusion length (Ln), the incident photon to current efficiency (IPCE) and the photoinduced charge (Qoc) increase markedly, while the dark current and the electron transit time (d) decreases for the TiCl4-treated nanoporous TiO2 films. The influence of TiCl4-treatment of nanoporous TiO2 film on the electron generation, the transport and the recombination processes is investigated at a microscopic level.
Features extraction from EEG signals induced by acupuncture based on the complexity analysis
Authors: Bian Hong-Rui  , Wang Jiang  , Han Chun-Xiao  , Deng Bin  , Wei Xi-Le  , Che Yan-Qiu  ,   (1)School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072, China; (2)Tianjin University of Technology and Education, Tianjin 300222, China
Published: December 2020

To explore the effects of acupuncture stimulation on brain activities, an experiment is designed that acupunctures at Zusanli point of the right leg are performed at four different frequencies to obtain electroencephalograph (EEG) signals. For the first time the complexity parameter of EEG is extracted by order recurrence plot and correlation dimension method, which reflects the functional state of the brain under acupuncture. The effects of acupuncture on the functional region of brain and correlation among different acupuncture frequencies and the complexity of EEG are investigated. The results show that the complexity of EEG during acupuncture is higher than that before acupuncture and especially during acupuncture at a frequency of 100 times/min. Furthermore, the determinism (DET) extracted from EEG signals of electrodes FP2, F7 and T3 can be used as a characteristic parameter of distinction between the state during acupuncture and the state before acupuncture.
The entanglement properties in the system composed of a -type atom and a V-type atom trapped in two distant cavities connected by an optical fiber
Authors: Lu Dao-Ming  ,   Department of Electronic Engineering, Wuyi University, Wuyishan 354300, China
Published: December 2020

We consider a system consisting of a -type atom and a V-type atom, which are individually trapped in two spatially separated cavities that are connected by an optical fiber. The evolution of the state vector of the system is given. We investigate the temporal evolution in the entanglement between atoms and that between cavities. We discuss the influence of cavity-fiber coupling coefficient on entanglement. The results obtained by the numerical method show that the entanglement between atoms and the entanglement between cavities have the same evolution regularities. On the other hand, the entanglement between atoms and that between cavities are strengthened with the increase of cavity-fiber coupling coefficient.
On the creation of spacetime volume and gravity in loop gravity
Authors: Shao Dan  , Shao Liang  , Shao Chang-Gui  ,   Institute of Light and Electronic Infromation, Jianghan University, Wuhan 430056, China;,   Department of Applied Physics, Wuhan University of Science and Technology, Wuhan 430081, China;,   Institute of Theoretical Physics, Hubei Education University, Wuhan 430205, China
Published: December 2020

Using the 4-simplex and its dual-skeleton spin networks, a quantum transition of pure spacetime is described. The change of vertex volumes between successive steps of the transition of the three-dimensional space woven by spin networks is demonstrated. At the same time, a model of quantum flate fluctuation of the four-dimensional spacetime is given. Employing the excitations created when the loops on the edges of spin network pierce sarfaces, a 2 order symmerric tensor hab is obtained in three-dimensional space. Based on the viewpoint that the spacetime is excitation and transition system, the creation and the change mechanisms of the gravitational field h are investigated.
Mean first-passage time and stochastic resonance in an asymmetric bistable system driven by non-Gaussian noise
Authors: Zhang Jing-Jing  , Jin Yan-Fei  ,   Department of Mechanics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

In this paper, mean first-passage time (MFPT) and stochastic resonance (SR) are investigated in an asymmetric bistable system driven by multiplicative non-Gaussian noise and additive Gaussian white noise. Using the path integral approach and two-state theory, the expression of MFPT and the signal-to-noise ratio (SNR) are derived. The results show that the influences of the asymmetric coefficient on the MFPTs in two opposite directions are entirely different. SNR is a non-monotonic function of the additive noise intensity and asymmetric coefficient, therefore, an SR is found in this system. Whereas SNR is a monotonic function of the multiplicative noise intensity and no SR appears. This demonstrates that the effect of the multiplicative noise intensity on SNR is different from that of the additive noise intensity in the system.
Reflection spectrum analysis of dropwise condensation with the clustering model
Authors: Lan Zhong  , Xu Wei  , Zhu Xia  , Ma Xue-Hu  ,   Institute of Chemical Engineering, Dalian University of Technology, Dalian 116012, China
Published: December 2020

The clustering phenomenon on the solid wall during dropwise condensation is analyzed with reflection spectrum. By the theoretical prediction of reflectivity of thin liquid films with different thicknesses on the stainless steel surface, it is ascertained that the reflectivity value is corresponding to the coacervate character of the steam molecular. Furthermore, by analyzing the experimental data of the reflection spectrum during dropwise condensation, presented in the literature, it is obtained that the reflection character and so the coacervate character lies between liquid and steam after the droplet has fallen off during an actual continuous condensation process. And the clustering model is used to analyze the results, which point out that clusters are formed on the blank surface. And it is found that the different microstructures of the solid wall can lead to different deposition rates of the clusters, which presents an effective way to enhance the heat transfer process of condensation by guickening the deposition rate of clusters with the surface modification.
Single attosecond pulse generated by model helium atom exposed to the combined field of an intense few-cycle chirped laser pulse and a half cycle pulse
Authors: Li Wei  , Wang Guo-Li  , Zhou Xiao-Xin  ,   Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Published: December 2020

We propose an efficient method to generate an ultrashort attosecond pulse when a model He is exposed to the combination of an intense few-cycle chirped laser pulse and a half cycle pulse. By solving the time-dependent Schrdinger equation numerically, we find that the cut-off energy of the harmonics is extended effectively to Ip+21.6Up. By superimposing some high-order harmonics in different regions for the second plateau, the obtained pulses are all single attosecond ones. Minimum pulse achieves 37 as. Especially, by superimposing the lower order harmonics of the second plateau, one can obtain single attosecond pulse, and also the intensity of the single pulse is three order of magnitude higher than the attosecond pulse obtained near cut-off of harmonics.
Normal mode splitting and cooling in strong coupling optomechanical cavity
Authors: Chen Hua-Jun  , Mi Xian-Wu  ,   College of Physics Science and Information Engineering, Jishou University, Jishou 416000, China
Published: December 2020

A model describing optomechanical dynamics via radiation-pressure coupling with a driven optical cavity is investigated by a linearized quantum Langevin equation. The spectrum of the oscillator presents normal mode splitting with the increase of the input laser power in strong coupling regime and our results are in good agreement with the experimental results. The effective mechanical damping and the resonance frequency shift are derived. The redshifted sideband leads to the cooling of the mechanical oscillator, and the blueshifted motional sideband results in amplification. Furthermore, an approximate mechanism is introduced to analyze the cooling of the mechanical oscillator. Since both the normal mode splitting and cooling require working in the resolved sideband regime, whether the normal mode splitting influences the cooling of the mirror is considered. Meanwhile, we give three key factors influencing the cooling of mechanical oscillator, these being initial bath temperature, input laser power and mechanical quality factor.
Fluorescence reabsorption analysis on laser cooling of Tm3+ doped ZrF4 -BaF2 -LaF3 -AlF3 -NaF-PbF2 glass
Authors: Jia You-Hua  , Zhong Biao  , Yin Jian-Ping  ,   College of Science, Shanghai Second Polytechnic University, Shanghai 201209, China;,   State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
Published: December 2020

Laser cooling of solid material has become a new developing research area in recent years. Tm3+ doped ZrF4-BaF2-LaF3-AlF3-NaF-PbF2 glass is one of the hot materials in this field. Compared with Yb3+, Tm3+ has better cooling potential. Up to date, one of the main factors restricting the cooling effect is fluorescent reabsorption. In this paper, firstly, using several spectral parameters of Tm3+, the reabsorption effect is calculated by stochastic model which is a semianalytical approach to this problem. The average number of absorption events is obtained. Afterwards, the effect of fluorescence trapping due to total internal reflection is analyzed. The results show that the quantum efficiency will be lowed by 0.5%1% due to reabsorption, that the redshift of the mean fluorescence wavelength is in the range of 210 nm, and that the cooling efficiency and the cooling power decrease. Finally, after discussion, we find that the use of a small size and a long thin geometry will benefit to the fluorescence emission and cooling effect.