bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigations on structures of supersonic laminar/turbulent flow over a compression ramp
Authors: Wu Yu  , Yi Shi-He  , Chen Zhi  , Zhang Qing-Hu  , Gang Dun-Dian  ,   College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China
Published: December 2020

Experimental investigations of supersonic laminar/turbulent flow over a compression ramp are carried out in a Mach 3.0 wind tunnel, the angles of ramp are 25 degrees and 28 degrees. Fine structures of holistic flow field and local regions are visualized via nanoparticle-tracer based planar laser scattering (NPLS) technique, some typical flow structures such as boundary layer, shear layer, separation shock, recirculation zone and reattachment shock are visible clearly, and the wall pressure coefficient of laminar flow is measured. The angle of separation shock and reattachment shock, the development of boundary layer after reattachment are measured by time-averaged flow field structures. The analyses of time-relevant NPLS images reveal the spatio temporal evolution characteristics of flow field. The experimental results indicate that when the ramp angle is 25 degrees, a typical separation appearing in the supersonic laminar flow with boundary layer increases and is converted into turbulence quickly, at the same time, a shock is induced by developing boundary layer; K-H vortexes, shear layer and compression waves arise in the flow field. But the supersonic turbulent flow does not show separation, and the turbulent boundary layer always adhers to the wall. When the ramp angle is 28 degrees, the range of recirculation zone expanded obviously in supersonic laminar flow which is separated further, induces shock and separation shock moves upstream, reattachment shock moves downstream. Therefore the structures of separated region is complicated. By comparison with laminar flow, the range of recirculation zone in supersonic turbulent flow is obviously small, boundary layer increases slowly, and there are not any induced shock, K-H vortexes, compression waves in the flow field. The structures of separated region is simple, but the strength of separation shock is much stronger.
Structure and dynamics in the crystallization of Ni500 nanocluster
Authors: Xu Zhi-Xin  , Li Jia-Yun  , Sun Min-Hua  , Yao Xiu-Wei  ,   Key Laboratory of Semiconductor Nanocomposite Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, China
Published: December 2020

Molecular dynamics simulations are performed on nano clusters with 500 nickle atoms (Ni500) to determine the structure and dynamics in the isothermal crystallization using embed atom model potentials. Through the study of nano Ni cluster dynamic behavior, we find that multi-step crystallization process of Ni500 is at temperatures far below the melting temperature (Tm), whereas one-step crystallization process is at the temperatures just below Tm. Multi metastable states are observed before Ni500 becomes fully crystallized in multi-step crystallization process. We find that atom rearrangements take not only string-like cooperative motion manner but also other collective motion manner.
Monte Carlo simulations of microstructure and texture evolution during annealing of a two-phase titanium alloy
Authors: Yang Liang  , Wei Cheng-Yang  , Lei Li-Ming  , Li Zhen-Xi  , Li Sai-Yi  ,   School of Materials Science and Engineering, Central South University, Changsha 410083, China;,   Guangdong Zhaoqing Supervision Testing Institute of Quality and Measuring, Zhaoqing 526060, China;,   AVIC Commercial Aircraft Engine Co. Ltd., Shanghai 200241, China;,   Beijing Institute of Aeronautical Materials, Beijing 100095, China;,   Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410012, China
Published: December 2020

Nucleation and grain growth are important phenomena during static recrystallization of metallic materials and both processes have significant influences on the material properties. The Monte Carlo (MC) method has been widely used to simulate static recrystallization behavior during annealing of metallic materials. In this study, an MC model for static recrystallization of two-phase alloys is proposed by extending an existing MC model, through the introduction of the nucleation stage to account for the grain growth by both consuming deformed grains and competing with other recrystallized grains. The two-phase MC model is used to simulate the evolution of microstructure and texture during annealing of a TC11 (Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) titanium alloy, accounting for initial grain morphology, phase compositions, crystallographic orientations, and relative values of strain stored energy determined by electron back-scattered diffraction. The results show that the model can reproduce satisfactorily the recrystallization and grain growth behavior in annealing. Compared with the β phase, the α phase depicts a lower recrystallization rate but a higher grain growth rate: the former difference can be mainly attributed to the lower strain stored energy in the α phase before annealing, whereas the latter suggests that the grain growth in the system is significantly influenced by the grain morphology, distribution of grains, and relative volume fractions of the two phases in the initial condition. Due to the influence of heterogeneous nucleation accounted for in the model, the simulated recrystallization rate deviates considerably from that described by the Johnson-Mehl-Avrami-Kolmogorov equation. The simulation also indicates that for both phases the textures strengthen with little changes in their basic features during annealing.
Thermal conductivities of metallic nanowires with considering surface and grain boundary scattering
Authors: Li Jing  , Feng Yan-Hui  , Zhang Xin-Xin  , Huang Cong-Liang  , Yang Mu  ,   School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China;,   School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
Published: December 2020

The contributions of phonon and electron transport to the thermal conductivities of Cu and Ag nanowires are studied theoretically. The effects of surface and grain boundary scatterings are involved. The embeded atom method is employed to express the interatomic potential of nanowires. While the molecular dynamic simulation and Green-Kubo formulation are used to obtain the lattice thermal conductivity, a model derived from Boltzmann transport equation and the Wiedemann-Franz relation are used to calculate electronic thermal conductivity. In addition, diffuse mismatch model is used to calculate thermal resistance of grain boundary to modify the lattice thermal conductivity, meanwhile, Mayadas-Shatzkes model is used to consider the influence of grain boundary scattering on the electronic thermal conductivity. By coupling the lattice and electronic thermal conductivity, the effective thermal conductivity of nanowire is obtained. On this base, the influences of size and temperature are analyzed. It turns out that Cu and Ag nanowires have a similar tendency in the thermal conductivity. The contribution of electron transport to the thermal conductivity of nanowire is dominated, but the contribution of phonon transport cannot be ignored on the nanoscale. The thermal conductivity of nanowire decreases due to the grain boundary scattering. And it decreases with temperature increasing or size decreasing. The contribution of phonon transport becomes more important in the case of smaller size.
First-principles calculations on electronic structures of Zn adsorbed on the anatase TiO2 (101) surface having oxygen vacancy and hydroxyl groups
Authors: Ma Li-Sha  , Zhang Qian-Cheng  , Cheng Lin  ,   Key Laboratory of Industrial Catalysis of the Inner Mongolia Autonomous Region, Inner Mongolia University of Technology, Huhehot 010051, China
Published: December 2020

The energies, atomic Mulliken charges, and electronic structures of Zn adsorbed on the pure surface, and on the surfaces with an oxygen vacancy (Zn-TiO2-VO) and one hydroxyl group (Zn-TiO2-VO-OH) are investigated by density functional theory, plane-wave pseudo-potential method, and the most stable surface structures (namely model (c), model (aI), and model (aII) are found. The results indicate that firstly, Zn interacts mainly with the surface oxygen by Zn–O covalent bond; secondly, when Zn atoms are adsorbed on the defective surface, the adsorption energy is reduced down to -1.75 eV, showing that Zn atoms are prone to being adsorbed on the oxygen vacancy surface. Finally, although no impurity states are introduced in to the gap when the Zn atoms are adsorbed to the surface with hydroxyl group, the band gap is reduced down to a minimum (1.85 eV), which is expected to improve the photocatalytic activity of TiO2.
Effect of double substitution of Ba and Ag on thermal transport of Ca3Co4O9-based thermoelectric oxide
Authors: Zhang Fei-Peng  , Duan Kun-Jie  , Zeng Hong  , Zhang Jiu-Xing  ,   Institute of Applied Science, Henan University of Urban Construction, Pingdingshan 467036, China;,   Advanced Technology and Materials Co., Ltd, China Iron and Steel Research Institute Group, Beijing 100081, China;,   National Key Laboratory of Advanced Functional Materials, Chinese Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

The Ba and Ag co-doped BaxAgyCa2.8Co4O9 thermoelectric bulk materials are fabricated by acid sol-gel and spark plasma sintering method. The phase compositions, microstructures and thermal transport properties of the resulting bulk materials are analyzed by X-ray diffraction, scanning electron microscopy and the thermal transport constant measurement apparatus. The results show that the thermal conduction behavior for the titled system can be effectively tuned by Ba and Ag co-doping, and the thermal conductivity could be reduced by increasing the Ba doping content. The analysis results show that the total thermal conduction suppressing comes from the lattice thermal conduction confinement. The Ba0.1Ag0.1Ca2.8Co4O9 bulk material is found to have the lowest thermal conductivity with total thermal conductivity and lattice thermal conductivity reaching 1.43 W/mK and 1.10 W/mK at 973 K, respectively.
Fabrication of multilayer metal-dielectric nanoparticles and their optical properties
Authors: Zhou Zhen-Ting  , Yang Li  , Yao Jie  , Ye Ran  , Xu Huan-Huan  , Ye Yong-Hong  ,   School of Physical Science and Technology, Nanjing Normal University, Nanjing 210046, China
Published: December 2020

We use nanosphere lithography and thermal evaporation techniques to fabricate multilayer metal-dielectric cone nanoparticle arrays. Scanning electron microscope measurements reveal that the ordered nanoparticles are of triangular shapes. Optical transmittance measurements show that there is a transmittance dip for each sample, and the transmittance dip is caused by the localized surface plasmon resonance of the metal/dielectric particles. With the increase of the number of the metal/dielectric layers of a sample, the position of the transmittance dip of the sample shows a blue-shift. Moreover, the transmittance spectrum and the electric field distribution of the metal/dielectric nanoparticles are simulated by HFSS, and the electric field distribution is used to explain the blue-shift phenomenon.
A novel solute redistribution model for cellular automaton and its validification
Authors: Li Ri  , Shen Huan-Di  , Feng Chang-Hai  , Pan Hong  , Feng Chuan-Ning  ,   Hebei University of Technology, Key Laboratory of Materials Processing and Control Engineering, Tianjin 300130, China
Published: December 2020

Based on the several solute redistribution models, a more reasonable solute redistribution model is presented. The cellular states on the solid/liquid interface and the states of its neighboring cells possibly occurring during the grain growth are fully considered in the model, and different formulas are built for different cases. Firstly, the simulation result shows that the disadvantage of the original cellular automation (CA) model (its grain growth is controlled by solute distribution), in which the cells on the grain boundary are kept unsolidified all the time, is eliminated. Then, in order to verify the reliability of the new model, the new model is introduced into the CA model in which grain growth is controlled by Kurz-Giovanola-Trivedi model. The microstructure of the Al-4.7 wt%Cu ingot is calculated. The simulation results are in good accordance with experimental results in two aspects of microstructure morphology and concentration distribution.
Characteristics of gate-modulated generation current under the reverse substrate bias in nano-nMOSFET
Authors: Chen Hai-Feng  ,   School of Electronic Engineering, Xi’an University of Posts and Telecommunications, Xi’an 710121, China
Published: December 2020

The characteristics of gate-modulated generation (GMG) current IGMG in nano-scale LDD nMOSFET under the reverse substrate bias VB are investigated. It is found that the rising and falling edges of IGMG curve shift rightwards as |VB| increases. On the basis of experimental and theoretical analysis, the physical mechanism behind this shift phenomenon is attained. The shift phenomenon is ascribed from the fact that VB modulates the proportion of surface potential φs in the gate bias VG. φs decreases with |VB| increasing under a certain VG, and consequently the maximum generation factor of the rising edge (gr) diminishes and that of the falling edge (gf) augments. Further, it is found that the transconductance peaks of the rising edge (GMR) and falling edge (GMF) increase with |VB| increasing. Moreover, GMR and GMF both have the linear relationship with VB in log coordinate. Due to the different roles of drain bias VD on the rising and falling edge of IGMG curve, GMR keeps constant but GMF varies under different values of VD. Increasing VD can enhance the change of gf with VG, there by increasing GMF under a given VB. Also, this results in the fact that the trend of GMF increasing with |VB| increasing slows down under a larger VD: the slop of GMF-VB curve decreases from 0.09 to 0.03 as VD increases from 0.2 to 0.6 V.
Research on the implementation of GPS radio occultation one-dimensional bending angle operator in four-dimensional variational data assimilation system
Authors: Zhu Meng-Bin  , Zhang Wei-Min  , Cao Xiao-Qun  ,   School of Computer Science, National University of Defense Technology, Changsha 410073, China
Published: December 2020

GPS radio occultation data are implemented in the numerical weather prediction as a kind of very important observation data because of its excellent characteristics, which makes a remarkable positive effect in the system. In this article, we design an implement method and a quality control strategy of one-dimensional bending angle operator in four-dimensional variational data assimilation system, and we also describe the steps of implementing one-dimensional bending angle forward operator and its linear and adjoint operators in four-dimensional variational data assimilation system. The author chose Reger’s three term expression and its best average coefficients are chosen to calculate refractivity values. In this article, we introduce an observation error model of one-dimensional bending angle operator through the statistics of GPS radio occultation observation data of August, 2012. A comparison of experiment of the analysis field between in the cases with and without GPS radio occultation data is made. It is concluded that GPS radio occultation data plays a positive role in the global areas, especially in the low and middle latitude areas higher than 10 km. This conclusion is the foundation of the following-up GPS radio occultation data assimilation verification experiments.
Pseudo-collision in swarm optimization algorithm and solution：rain forest algorithm
Authors: Gao Wei-Shang  , Shao Cheng  , Gao Qin  ,   School of Control Science and Engineering, Dalian University of Technology, Dalian 116024, China;,   Institute of Adanced Control Technology, Dalian University of Technology, Dalian 116024, China
Published: December 2020

Pseudo-collision (Pc) as a common but neglected phenomenon in swarm optimization algorithm is revealed in this paper. Mechanism analysis on the inevitability of Pc indicates that both the lack of relation among samples and the unconstrained behavior of sampling are the inherent character of agent operation causing Pc in state-of-the-art swarm algorithms such as genetic algorithm (GA) and particle swarm optimization (PSO). Based on the result of mechanism analysis, a novel partition management and classification sampling strategy is proposed to reduce Pc. In addition, both uniform and non-uniform principles are designed to facilitate the trade-off between exploration and exploitation during optimization. Rain forest algorithm (RFA), of which the evolution mechanism is identical with the above strategy and the principles, is proposed in this paper. By examining the rapidity, accuraty, and generalization capability across six benchmark nonconvex functions, RFA is found to be competitive with or even superior to GA and PSO in dealing with complex multi-peak optimization.
Sudden birth versus sudden death of entanglement during the interaction of macroscopic fields with environments
Authors: Luo Cheng-Li  , Shen Li-Tuo  , Liu Wen-Wu  ,   Institute of Electronic Information Engineering, Sunshine College Fuzhou University, Fuzhou 350002, China;,   Lab of Quantum Optics, Department of Physics, Fuzhou University, Fuzhou 350002, China
Published: December 2020

Decoherence of two initially entangled macroscopic fields each interacting with a loss environment is investigated; environment only have an effect on the leakage of field’s photons. The cavity-cavity entanglement is characterized by concurrence. The results obtained by resolvable values show a surprising result: the two entangled macroscopic fields become completely disentangled even though the leakage rate of the cavities fields is very tiny. Then we find that when the cavity entanglement disappears, the environment entanglement appears. Finally, we present an explanatory study of other entanglement partitions.
Thermal entanglement in a {Cu3} single molecular magnet in the magnetic field
Authors: Li Ji-Qiang  , Cheng Zhi  , Zhou Bin  ,   School of Physics and Electronic Technology, Hubei University, Wuhan 430062, China
Published: December 2020

We have investigated the properties of thermal entanglement in a triangular spin ring of the single molecular magnet (SMM) Na9[Cu3Na3(H2O)9 (α-AsW9O33)2]·26H2O in a magnetic field, and the pairwise concurrences of arbitrary two Cu2+ ion qubits are calculated numerically, hereafter abbreviated as C12, C23 and C13, respectively. Results show that the magnitude and direction of magnetic field as well as temperature have important effects on the pairwise thermal entanglement. Moreover, C12, C23 and C13 have difference variations with the change of the parameters. We also plot the changes of the critical temperatures Tc of C12, C23 and C13 with the magnetic fields along three different directions, and from the critical temperature-magnetic field phase diagrams one can obtain the ranges of parameters in which the pairwise thermal entanglement in a triangular spin ring of the SMM exists. Therefore, the pairwise entanglement can be controlled and enhanced in the SMM by choosing appropriate magnitude and direction of magnetic field and temperature.
Analysis of transfer orbit deviation propagation mechanism and robust design for manned lunar landing
Authors: He Bo-Yong  , Li Hai-Yang  , Zhang Bo  ,   College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China
Published: December 2020

Earth-moon transfer orbit for manned lunar landing needs a long flight time, complex, nonlinear and variable coefficient dynamics model, and asks for a high reliability. Analysis of deviation propagation mechanism and robust design of transfer orbit are investigated in this paper. It is not only practical for projecting, but also significant for exploring the role of earth-moon space gravitational field upon transfer orbit deviation. This paper analyses firstly the boundary and the amplitude of the sun, earth, and moon central gravitation, the earth J2 perturbation that affect the transfer orbit deviation transmission. And then a method to analyse the deviation propagation mechanism based on nominal orbital data is obtained analytically. A robust indicator of transfer orbit based on deviation transition matrix is proposed,and a robust optimization design method that employs NSGA-II(nondominated sorting genetic algorithms) for earth-moon transfer orbit with robust indicator is proposed.Simulation shows that the analysis of transfer orbit deviation propagation mechanism can obtain earth-moon transfer orbit deviation propagation matrix quickly and precisely, and the deviation propagation matrix can be used to obtain the covariance matrix and mid-course correction delta V analytically and exactly. The quality of nominal transfer orbit is improved by optimizing with robust indicator.
Fuzzy fast terminal sliding mode controller using an equivalent control for chaotic oscillation in power system
Authors: Ni Jun-Kang  , Liu Chong-Xin  , Pang Xia  ,   State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China; School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

Chaotic oscillation in a power system is taken to be the main cause for power blackouts in large-scale interconnected power grid. This paper studies a 2-D power system with chaotic oscillation dynamic behaviors through parameter phase portraits, Lyapunov exponents, time-domain waveform graph and proposes fuzzy fast terminal sliding mode controller based on equivalent control to stabilize the power system to synchronization status. Simulation results show that our control scheme can not only speed up convergence rate, but also have smooth control action, reduce control energy and suppress chattering phenomenon effectively.
Directed transport of elastically coupled particles in a two-dimensional potential
Authors: Wu Wei-Xia  , Zheng Zhi-Gang  ,   Science Education Department, Beijing Institute of Graphic Communication, Beijing 102600, China;,   Department of Physics, Beijing Normal University, Beijing 100875, China
Published: December 2020

A transport model of elastically coupled particles in a two-dimensional potential is investigated. Here, we propose that one dimension of the model is exerted by an AC drive and an external noise, and the other dimension by neither AC drive nor external noise. The effects of system and external parameters on the directed current under an overdamped case are discussed. The studies show that particles can transfer energy from one direction to its perpendicular direction through coupling, thereby producing a directed current. There is an optimal value of the spring free length or the coupling intensity at which the directed current can reach a maximum. For a fixed coupling intensity or noise intensity, the directed current will oscillate as the free length of spring varies, that is, multiple peaks appear. Moreover, a stochastic resonance appears in the directed current as noise intensity varies. Finally, when the degree of asymmetry of the ratchet potential achieves a maximum value, the current reversion takes place.
Quantum-dot gated field effect enhanced single-photon detectors
Authors: Wang Hong-Pei  , Wang Guang-Long  , Ni Hai-Qiao  , Xu Ying-Qiang  , Niu Zhi-Chuan  , Gao Feng-Qi  ,   Laboratory of Nanotechnology and Microsystems, Ordnance Engineering College, Shijiazhuang 050003, China;,   National Laboratory for Superlattics and Microstructures, Institute of Semmiconductors, Chinese Acdemy of Sciences, Beijing 100083, China
Published: December 2020

In order to solve the problem of low light absorption efficiency of single photon detectors based on quantum-dot gated field effect transistor (QDFET), a new type of quantum-dot gated field effect enhanced single-photon detectors (QDFEE-SPD) was proposed. QDFEE-SPD was designed with a resonant cavity, and the GaAs/AlAs multilayer was used as the basic mirror. The light absorption efficiency and responsivity of QDFEE-SPD were analyzed and simulated. Results show that, compared with that without cavity, the absorption efficiency and responsivity of the QDFEE-SPD is greatly improved. Also for the optimization of light absorption efficiency, the thickness of the absorption layer should normally be 0.10.5 m. Then the material samples of QDFEE-SPD were grown and tested. Reflection spectroscopy and PL spectroscopy testing results show that the light absorption efficiency has been significantly enhanced. The achievements in this article provide a new way for researching high-efficiency single-photon detection technology based on QDFET.
Timbre representation and property analysis of underwater noise based on a central auditory model
Authors: Yang Li-Xue  , Chen Ke-An  , Wu Ying  ,   Department of Environment Engineering, Northwestern Polytechnical University Xi’an 710072, China
Published: December 2020

In order to establish quantitative timbre representation of underwater noise, this paper tries to build a relationship between essential timbre scores and central auditory responses to stimulus based on partial least squares regression, and use regression coefficients to interpret the physical meaning of each dimension. In order to verify the utility of this method, this paper extracts a large amount of timbre descriptors as independent variables for comparisons, and it is shown that the predictive ability of the central auditory model is better. Finally it is found from two types of timbre representations that the first three dimensions in the timbre space can be respectively interpreted as high-frequency energy ratio, spectral flatness and temporal continuity; however, dimension 4 cannot be related to any acoustical features.
Investigations on the process of droplet impact on an orifice plate
Authors: Li Da-Ming  , Wang Zhi-Chao  , Bai Lin  , Wang Xiao  ,   State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China
Published: December 2020

To investigate the process of droplet impact on an orifice plate, a two-dimensional SPH model is established. An improved linked-list search algorithm with improvement of computational domain changing with fluid is described. By analyzing the numerical results with the experimental data, influences of viscosity, gravity, and internal pressure on the spreading of droplet over the orifice are studied. It is demonstrated that spreading will change to jet flow after the droplet reaches the orifice, and then the jet will pass it rapidly and in this rather short time the effect of gravity contributes very litte to the motion. However, viscosity can induce the jet to move in a curve into the orifice. Besides, with the internal pressure and inertial effect, the lower part of the jet will fluctuate regularly. The fluctuations make the jet repeat inflation and absorption to absorb the fluid from higher pressure area, resulting in Hole Suction phenomenon. Through analyzing the pressure of the vertical section of orifice edge, we find that internal pressure plays a significant role to the droplet which is absorbed into the orifice and finally leads to splashing. Numerical results are in good agreement with the experimental data.
Investigations on radiative opacity measurement by the method of direct laser-heating and self-backlighting
Authors: Zhang Ji-Yan  , Yang Jia-Min  , Yang Guo-Hong  , Ding Yao-Nan  , Li Jun  , Yan Jun  , Wu Ze-Qing  , Ding Yong-Kun  , Zhang Bao-Han  , Zheng Zhi-Jian  ,   Research Center of Laser Fusion, CAEP, Mianyang 621900, China;,   Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

A target designed for opacity studies of dense plasmas by laser direct heating and self-backlighting technique was presented and tested. The backlight source and sample plasma were generated by directing a frequency-tripled Nb-glass laser onto an Au/CH/Al/CH multilayer target on the XG-II laser facility, and the absorption of the sample plasma was obtained by measuring the attenuated backlight spectrum of the sample plasma. One-dimensional radiative hydrodynamic code Multi-1D was used to simulate the laser heating of the multilayer target, and the temperature and density profiles in the target were given. Experimental data were compared with the theoretically calculated spectra using the detailed-term-accounting model, which showed a temperature range from 20 eV to 70 eV in the sample plasma, a result in quite good agreement with the Multi-1D simulations.
Deuterium retention in carbon-tungsten co-deposition layers prepared by RF magnetron sputtering
Authors: Zhang Wen-Zhao  , Tang Xing-Hua  , Li Jia-Qing  , Shi Li-Qun  ,   Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Fudan University, Shanghai 200433, China;,   Department of Nuclear Science and Technology, Fudan University, Shanghai 200433, China
Published: December 2020

The C-W co-deposition layer prepared by radio frequency magnetron sputtering was investigated to identify the characteristic of the C-W mixed layers in fusion experimental reactors. Layers were characterized by ion beam analysis (IBA), Raman spectra (RS) and scanning electron microscopy (SEM). It was found that D atoms in C-W layers are mainly trapped by the trapping site of C atoms, only a few of them are arrested by W atoms or defects. D concentration in the C-W layers deposited at 5.0Pa with a fixed flow rate ratio QD2/QAr=2.5 was lower than 10% and decreased slightly with increasing temperature. D concentration increased with the gas pressure from zero to 5 Pa and then decreased from 5 Pa to 10 Pa. RS revealed that the crystal structure of the C-W layers became graphite-like with increasing temperature. SEM images showed that the caves disappeared and convex bodies were dotted on the surfaces as the temperature increased.
Influence of ZnS modification on the I-V performance of ZnO nanorods：P3HT composite films
Authors: Wang Li-Shi  , Xu Jian-Ping  , Shi Shao-Bo  , Zhang Xiao-Song  , Ren Zhi-Rui  , Ge Lin  , Li Lan  ,   College of Electronic and Information Engineering, Tianjin University of technology, Tianjin 300384, China;,   Institute of Materials Physics, Tianjin University of technology, Tianjin 300384, China;,   College of Science, Tianjin University of Technology and Education, Tianjin 300222, China
Published: December 2020

In this paper, the ZnO nanorod arrays (NRAs) with a diameter of 50nm and a length of 250 nm were synthesized by chemical bath deposition method. Two devices with structures of ITO (indium tin oxides)/ZnO/poly-(3-hexylthiophene) (P3HT)/Au and ITO/ZnO@ZnS/P3HT/Au were fabricated and their performances were tested and evaluated separately. The I-V curves were measured for discussion of the threshold voltage, series resistance, reverse leakage current, and rectification ratio. Results show that the device with modified ZnO shows a decline in the threshold voltage, series resistance and reverse leakage current, but has an enhanced rectification ratio. The effect of ZnS coating on the improvement of conductive properties of the device could be attributed to the suppression of the non-radiative recombination of surface defects as shown by means of photoluminescence spectrum.
Synthesis and properties of LaxCe1-xB6 compounds by in-situ spark plasma sintering
Authors: Bao Li-Hong  , Narengerile  , O. Tegus  , Zhang Xin  , Zhang Jiu-Xing  ,   Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, College of Physics and Electronic Information, Inner Mongolia Normal University, Hohhot 010022, China;,   The Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

Polycrystalline rare-earth hexaboride (LaxCe1-x)B6 were prepared by means of the reactive spark plasma sintering (SPS), using mixed powders of GdH2, NdH2 and B. The crystal structure, surface texture, mechanical property, electrical resistivity, and thermionic emission properties of the sintered samples were investigated. It is found that all the samples sintered by SPS exhibit high densily (>96%) and high value of Vickers hardness (2310 kg/mm2), which are much higher than those made by traditional method. Thermionic emission results indicate that the maximum emission current density of La0.6Ce0.4B6 is 40.7 A/cm2 under the applied voltage of 1 kV at 1873 K, which is larger than that of LaB6 and CeB6. Thus, the mixed cystal of borides (LaxCe1-x)B6, as a cathode, promises good prospects in application.
Light absorption enhancement in polymer solar cells with nano-Ag
Authors: Li Guo-Long  , He Li-Jun  , Li Jin  , Li Xue-Sheng  , Liang Sen  , Gao Mang-Mang  , Yuan Hai-Wen  ,   Ningxia Key Laboratory of PV materials, Ningxia University, Yinchuan 750021, China;,   Beifang University of Nationalities, Yinchuan 750021, China
Published: December 2020

The thickness of an active layer is limited by its low mobility of carriers in a polymer solar cell composed of the blend bulk-heterojunction formed by P3HT as donor material and PCBM as acceptor material, which can affect the light absorption of the polymer solar cell. Metal nanocrystals-doped polymer active layer can enhance its inner electrical field and absorb light due to the surface plasmon resonance (SPR) effect of the nanocrystals. Two-dimensional electrical field distributions in the polymer solar cells are simulated based on finite difference time domain (FDTD) approach, under the assumption that the diameter of doping nano-Ag is 50 nm, the distance between two nanocrystals is 50nm and the incident light wavelength is 400 nm or 500 nm. The electrical field distributions over the cross-section of nano-Ag are also simulated at the incident light angle of 15°, 45°, 60°, respectively. The light absorption of different devices are calculated, in which the sizes of nano-Ag take 10 nm, 20 nm and 50 nm, respectively, Particles of nano-Ag are dispersed in PEDOT:PSS layer. Moreover, the light absorption is calculated at the incident light angles of 15°, 45°, 60°, respectively. Results show that the electrical field is redistributed due to the SPR effect caused by nano-Ag in the polymer active layer. A larger size of nano-Ag leads to light scattering in a wider angle, thus results in more light absorption by the device. Here, the colloid of nano-Ag is prepared from an organic salt of Ag, and the polymer solar cell with nano-Ag is fabricated in the structure of glass /ITO (～100 nm) /PEDOT:PSS (40 nm) /P3HT:PCBM (～100 nm)/(nano-Ag) /LiF (1 nm) /Al (120 nm). Furthermore, experimental results show that the nano-Ag doped in P3HT:PCBM layer increases light absorption and improves the electrical performance of the device, which enhances the incident photon conversion efficiency (IPCE) in spectrum at 520nm by 17.9%.
Effective length of quantum confinement and polaron effect in a GaAs film
Authors: Liu Bing-Can  , Li Hua  , Yan Liang-Xing  , Sun Hui  , Tian Qiang  ,   Department of Fundamental Courses, Academy of Armored Force Engineering, Beijing 100072, China;,   Department of Physics, Beijing Normal University, Beijing 100875, China
Published: December 2020

The polaron confined in a GaAs film deposited on AlxGa1-xAs substrate are investigated in the framework of the fractional-dimensional space approach. We propose a new approach to define the effective length of quantum confinement. Limitations of the definition of original effective well width are discussed. The dimension and the binding energy of a polaron confined in a GaAs film deposited on Al0.3Ga0.7As substrate are obtained and investigated.
Preparation and luminescent properties of Ca3Si3O9：Dy3+ phosphors for white LED
Authors: Qi Zhi-Jian  , Huang Wei-Gang  ,   College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China
Published: December 2020

A novel Ca3Si3O9:Dy3+ phosphor for white LED was prepared by sol-gel method. The structure and luminescent properties of Ca3Si3O9:Dy3+ phosphors with different concentration of Dy3+ and charge compensator Li+ were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectra. Results show that the emission spectrum consists of two main band peaks locatied at 483 nm and 577 nm, while the peaks of excitation spectrum are located in the rang of 290–480 nm. Both of luminescent intensity and the ratio of yellow to blue emission (Y/B) increase first and then decrease with increasing Dy3+ concentration; and the luminescent intensity reaches a maximum when Dy3+ concentration is of 1 mol%. The luminescent intensity of Ca3Si3O9:Dy3+can be enhanced by Li+, and the blue emission increases greatly when Li+ concentration is within the range of 2 to 4 mol%.
Low-temperature combustion synthesis and luminescent properties of SrMgAl10O17：Eu2+, Er3+ high brightness blue phosphors
Authors: Liu Dan  , Liang Pei  , Wang Le  , Xu Guo-Tang  , Liu Yang  , Li Xiao-Yan  , Dong Qian-Min  , Huang Jie  ,   College of Optics and Electronic Science and Technology, China Jiliang University, Hangzhou 310018, China
Published: December 2020

The SrMgAl10O17:Eu2+ and SrMgAl10O17:Eu2+, Er3+ blue phosphors were synthesized by the combustion synthesis method. Their crystal structures and luminescent properties were analyzed by X-ray diffraction (XRD)、scanning electron microscope (SEM) and photoluminescence spectra, respectively. The XRD and SEM results indicate that the sample is well-crystallized in the combustion procedure, and its crystal structure has not changed when doped with low concentrations of rare-earth ions. PL results show that the phosphor of SrMgAl10O17:Eu2+ can be effectively excited by near UV LED chip with a broad emission spectrum extending from 430 nm to 520 nm, and has main peaks located at 460nm. Furthermore, the sample of the luminous intensity is the largest when the Er2+, Er3+ co-doped concentration is 4%, and the emission intensity of Sr0.95MgAl10O17:0.05Eu2+, Er3+ phosphor is significantly enhanced 54.9% higher than that of SrMgAl10O17:Eu2+ phosphor. It is indicated that Er3+has good sensitization effect for Eu2+ in luminescence, and this can be explained by the theory of energy transfer.
Deposition and first-principles caculation of carbon-doped titanium monoxide films
Authors: Xie Dong  , Leng Yong-Xiang  , Huang Nan  ,   School of Physical Science and Technology, Southwest Jiao tong University, Chengdu 610031, China;,   Key Laboratory for Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiao tong University, Chengdu 610031, China
Published: December 2020

Carbon-doped titanium monoxide films were successfully fabricated using CO2 as reactive gas by means of DC reactive magnetron sputtering. Phase tructure, composition and resistivity of the fabricated films were investigated by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and four point probe method. Results show that the fabricated film has a cubic phase structure, and the carbon element exists mainly as anion in the lattice of C-TiO. The resistivity of C-TiO is 52.2 μΩ·cm which is lower than that of pure TiO. Results of first principles calculation show that the Fermi levels of both TiO and C-TiO lie in their conduction bands, thus TiO and C-TiO have characteristics of metal conduction. Also the results of first principles calculation show that impurity levels of C 2p lie near the conduction band of C-TiO, which extend the width of conduction band and increase the density of states near the Fermi level of C-TiO, so the conductivity of C-TiO is larger than that of undoped TiO. The theoretical calculations are in agreement with experiment results.
Status and development of frequency selective surface radome
Authors: Lu Ge-Wu  , Zhang Jian  , Yang Jie-Ying  , Zhang Tian-Xiang  , Kou Yuan  ,   College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China;,   Aerospace Research Institute of Special Materials and Processing Technology, Beijing 100074, China
Published: December 2020

Due to the working characteristics of radar system, i.e. it has to ensure the emission and acceptance of its own radar wave, frequency selective surface (FSS) radome is the most effective stealthy way to give radome the function of frequency-selective. Combining the FSS technique and the radome together, FSS radome provides bandpass transmission properties in the operating frequency of radar, and changes the RCS characteristics of the antenna compartment when it is beyond the antennas operating frequency range, thus it is a realization of out-of-band stealth. This paper introduces the basic design of FSS radome technology and summarizes the research status of FSS radome in the structure design and the technology. The muti-band FSS radome, intelligent FSS radome, thick-screen FSS radome, miniaturized element FSS radome and the technologies to construct radome are predicted to be the perspective of FSS radome.
Direction of arrival of EMW and polarization parameter estimation using tripole near the earth surface
Authors: Sun Jie  , Zhang Xiao-Juan  , Fang Guang-You  ,   Key Laboratory of Electromagnetic Radiation and Sensing Technology, Chinese Academy of Sciences, Beijing 100190, China;,   University of Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

Based on the principal theory of tripole antenna in free space to compute the polar angle and azimuth angle of the incident electromagnetic wave (EMW), and the relations between each component of electric field and polarization, the formula for computing direction of arrival (DOA) of left-hand polarization electromagnetic wave and the method of determining the sense of the incident wave are presented. A novel method to filter out the reflected wave from the earth surface is put forward, which ensures the accuracy of the DOA, various polarization parameters are gained from DOA computed and electric field intensity, these polarization parameters serve as reference data for research of ionosphere and electromagnetic wave propagation in the ionosphere.
An evolving model for hypergraph-structure-based scientific collaboration networks
Authors: Hu Feng  , Zhao Hai-Xing  , He Jia-Bei  , Li Fa-Xu  , Li Shu-Ling  , Zhang Zi-Ke  ,   School of Computer Science, Shaanxi Normal University, Xi’an 710062, China;,   School of Computer, Qinghai Normal University, Xining 810008, China;,   Web Sciences Center, University of Electronic Science and Technology of China, Chengdu 611731, China;,   Institute of Information Economy, Hangzhou Normal University, Hangzhou 310036, China
Published: December 2020

In this paper, by considering the collaborative scientific behaviors, a model for evolving hyper-network is proposed based on the hypergraph theory. We study analytically the dynamics of authors’ hyper-degree using mean-field approach. Results of both theoretical and numerical studies indicate that such a hyper-degree distribution follows a power-law decay, with the exponent γ=1+L/M, where L/M suggests the author growth rate of an evolving scientific network. In addition, empirical studies on ten-year journal data of Science China and Acta Physica Sinica from 2003 to 2012, shows that the present model can find good agreement with the empirical data. The proposed model may shed some light on the in-depth understanding of the structure and scientific collaboration networks.
Spatial and temporal characteristics of moisture cycle factors over China analyzed with ERA-Interim reanalysis data
Authors: Zhou Jie  , Wu Yong-Ping  , Feng Guo-Lin  , Hu Jing-Guo  ,   Department of Physical Science and Technology, Yangzhou University, Yangzhou 225002, China
Published: December 2020

In this paper, we analyze the spatial and temporal characteristics of different moisture cycle factors over China by using the ERA-Interim data supplied by the European Centre for medium-range weather forecasts (ECMWF). The methods used in this paper include mainly the empirical orthogonal function (EOF), similarity coefficients, one-dimensional linear regression and so on. Results show that the spatial distribution of evaporation, zonal and meridional moisture flux are all extremely similar to that of precipitable water. While the spatial distribution of precipitable water and precipitation are both very similar to that of evaporation. The similarity coefficient between precipitation and zonal moisture flux is a little larger than that between precipitation and meridional moisture flux. In terms of temporal characteristics, it is shown that precipitation has an obvious upward trend during 1979–2002 and an obvious downward trend during 2002–2011. The trend of evaporation is the same as that of precipitation during the same period, but the former is more obvious than the latter. Besides, evaporation also shows an obvious upward trend during 1979–2011. Both of precipitable water and moisture flux divergence show a slightly downword trend. Zonal and meridional moisture flux change in a period of 2–3 years. Further, zonal moisture flux has an obvious downward trend during 1979–2011. The vapor flux has an obvious downward trend both in spring and autumn, and changes in a period of 2–3 years for all four seasons. Besides, the vapor flux in summer presents a decadal transition.
New infinite sequence soliton-like solutions of (2+1)-dimensional generalized Calogero-Bogoyavlenskii-Schiff equation
Authors: Taogetusang  ,   The College of Mathematical Science, Inner Mongolia Normal University, Huhhot 010022, China
Published: December 2020

This paper will study in detail homogeneous linear ordinary differential equation with constant coefficients of second order and draw new conclusion to construct new infinite sequence soliton-like solutions of high-dimensional nonlinear evolution equations. Step one: the solving of a homogeneous linear ordinary differential equation with constant coefficients of second order is changed into the solving of the quadratic equation with one unknown and the Riccati equation. Based on this, new infinite sequence solutions of homogeneous linear ordinary differential equation with constant coefficients of second order are found by using nonlinear superposition formula for the solutions to Riccati equation. Step two: new infinite sequence soliton-like solutions to (2+1)-dimensional generalized Calogero-Bogoyavlenskii-Schiff equation are constructed using the above conclusion and the symbolic computation system Mathematica.
Parameter-induced stochastic resonance in multi-frequency weak signal detection with stable noise
Authors: Jiao Shang-Bin  , Ren Chao  , Huang Wei-Chao  , Liang Yan-Ming  ,   Faculty of Automation and Information Engineering, Xi’an University of Technology, Xi’an 710048, China
Published: December 2020

In this paper we combine stable noise with bistable stochastic resonance to investigate the parameter-induced stochastic resonance in the high-and low-frequency (both for multi-frequency) weak signal detection with different stable noise, and explore the action laws between the stability index (0 2) and skewness parameter (-1 1) of stable noise, and the resonance system parameters a, b on the resonant output effect. Results show that for different distribution of stable noise, the high- and low-frequency weak signal detection can be realized by tuning the system parameters a and b. The intervals of a and b which can induce stochastic resonances are multiple, and do not change with or . Moreover, while detecting the high- and low-frequency weak signal, the action laws of the resonant output effect which are affected by or are the same. These results will contribute to realize a reasonable selection of parameter-induced stochastic resonance system parameters under stable noise, and lay the foundation for a practical engineering application of multi-frequency weak signal detection based on the stochastic resonance.