bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrothermal synthesis of K, Na doped Cu-S nanocrystalline and effect of doping on crystal structure and performance
Authors: Wan Bu-Yong  , Yuan Jin-She  , Feng Qing  , Wang Ao  ,   College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 400047, China;,   Key Laboratory of Optoelectronic Functional Materials of Chongqing, Chongqing 400047, China
Published: December 2020

Cuprous sulfide (Cu2S) nanocrystals and K or Na doped KCu7S4 nanowires and NaCu5S3 micro-nanospheres have been synthesized successfully by using a simple hydrothermal method, using KOH or NaOH as mineralizing agent, CuCl22H2O and S powders as copper and Sulfur sources, respectively. The structure and morphology are characterized and analyzed by X-ray diffraction (XRD), energy dispersive X-ray spectrum (EDS), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results reveal that under conditions that the amount of KOH is below 1g or the amount of NaOH below 2 g, the product is of the orthorhombic chalcocite Cu2S, while with high alkali amount (no less than 3 g), K+ or Na+ is successfully incorporated into the Cu-S structure; KCu7S4 has the pure tetragonal single crystal structure, and its uniform nanowires can be up to several tens of micrometers in length. Na doping has no effect on the morphology of the product, which forms the hexagonal NaCu5S3. The formation and growth of the product are closely related to the reaction temperature, reaction time and mineralizing agent. And, the formation and doping mechanisms are discussed. Finally, the influence of the alkali metal ion doping on the optical properties of the product is investigated. The diffuse reflectance spectra demonstrate that the optical band gaps of Cu2S, NaCu5S3 and KCu7S4 nanocrystallines is 1.21, 0.49, 0.42 eV, respectively. And K+ or Na+ doping greatly affects the optical characteristics.
Structural characterization and magnetic properties of perpendicularly magnetized MnAl films grown by molecular-beam epitaxy
Authors: Nie Shuai-Hua  , Zhu Li-Jun  , Pan Dong  , Lu Jun  , Zhao Jian-Hua  ,   State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
Published: December 2020

Perpendicularly magnetized MnAlx thin films with different Al contents have been epitaxied on GaAs (001) substrates by a molecular-beam epitaxy system. Crystalline quality of MnAlx films is closely related to Al content, and magnetic properties of MnAlx films are improved as crystalline quality of MnAlx fims increases. MnAl0.9 film shows the best crystalline quality and magnetic property among all samples. So we grew MnAl0.9 films at different growth temperatures to further optimize growth conditions. With increasing temperature, the chemical order parameter increases and the full width at half maximum of the τ(002) peak decreases, which reveal the improvement of crystalline quality. Higher perpendicular magnetization, coercivity and magnetic anisotropy are found as growth temperature increases. The best crystalline quality and perpendicularly magnetized properties are found at 350℃; the coercivity of 8.3 kOe, saturation magnetization of 265 emu/cm3, Mr/Ms of 0.933 and perpendicular magnetic anisotropy constant of 7.74 Merg/cm3 are achieved. These tunable perpendicularly magnetized properties and good compatibility associated with semiconductor materials make the noble-metal-free and rare-earth-free MnAl films attractive in the application of spintronic devices.
Injection-locking of magnetrons with matched impedance
Authors: Yue Song  , Zhang Zhao-Chuan  , Gao Dong-Ping  ,   Key Laboratory of High Power Micriwave Sources and Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Coherent power-combining by using several magnetrons is essential because the output power of one single magnetron cannot meet the need of large-scale industrial applications. In order to obtain phase coherence condition of the power-combining of normal magnetrons, injection-locking technology should be adopted to make sure the stability of the operating frequency and phase difference. Under impedance matching conditions, equivalent circuit of injection-locked magnetron is analyzed with the conditions of the magnetron stable frequency. The small injection-ratio and large injection-ratio situations of the injection-locked magnetrons are both derived. Furthermore, large injection-ratio situation indicates a greater frequency-locked bandwidth than small injection-ratio situation. Theoretical results are analyzed by MATLAB and injection-locked theory is verified by three-dimensional particle-in-cell simulation. The frequency-locked bandwidth and phase differential equation are given and curves of the phase difference are drawn for different initial phases. Output power and frequency of A6 magnetron are obtained by simulation under both free and injection-locked oscillation conditions. Simulation results show that magnetron can be locked and working stably in frequency-locked bandwidth predicted by both situations. Moreover, in the large injection ratio status the large injection-ratio situation is more accurate than the small injection-ratio situation.
Finite-time stability control of permanent magnet synchronous motor chaotic system with parameters uncertain
Authors: Tang Chuan-Sheng  , Dai Yue-Hong  ,   School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
Published: December 2020

A novel active finite-time stability controller is presented for permanent magnet synchronous motor chaotic system considering parameters uncertain. The controller combines with active control and finite-time stability theory. Adjusting the parameters of terminal attractor, this controller has not only strong robustness but also good responsiveness. Simulation results show that the proposed controller has superior performance than traditional one.
Phase-field modeling of vacancy cluster evolution in Fe
Authors: Liang Lin-Yun  , Lü Guang-Hong  ,   School of Physics and Nuclear Energy Engieering, Beihang University, Beijing 100191, China
Published: December 2020

A quantitative phase-field model is developed to study the evolution of vacancy cluster in Fe. Total energy of the system is constructed based on the assumption of ideal gas state equation, and an approach to linking the computational parameters in the phase-field model to the experimental properties of Fe is provided. Such a phase filed model is employed to quantitatively investigate the nucleations, growths, and coalescences of voids in single and polycrystalline Fe. The effects of grain boundary on voids evolution are also investigated. These results provide a way of further studying the evolution behaviors of both H/He gas atoms and voids in Fe.
Charge transport properties of truxene derivatives molecules
Authors: Jian Lei  , Tan Ying-Xiong  , Li Quan  , Zhao Ke-Qing  ,   Key Laboratory of Advanced Functional Materials, Sichuan Province Higher Education System, College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
Published: December 2020

According to Einstein’s equation and Marcus charge transport model, the structures and charge transport rates of six truxene derivative molecules are calculated using the density functional theory at B3LYP/6-31g** theoretical level. The results show that the hole and electron transport rates of the six truxene derivative molecules are 0.018-0.062 and 0.055-0.070 cm2·V-1·s-1, respectively, and the truxene derivative molecule with 3, 8, 13-three octyloxy chains can be designed into dual polarity transport materials. In truxene derivative molecules with three alkoxy chains, introduction of three methoxyl or hydroxyl group could reduce hole and electron transport rate. The introduction of electron-donating groups or conjugated groups would reduce the energy gap of truxene derivative molecules, which meet the requirements for the organic semiconductor.
Influence of Ξ-type three-level atomic Bose-Einstein condensate on the squeezing properties of light field
Authors: Li Ming  , Chen Ding-Han  , Chen Cui-Ling  ,   College of Science, Guilin University of Technology, Guilin 541004, China;,   College of Mathematics Science, Guangxi Normal University, Guilin 541004, China
Published: December 2020

The Hamiltonian operator of a system of Ξ-type three-level atomic Bose-Einstein condensate interacting with single-mode squeezed coherent light field is improved in terms of the lattice-liquid model, and the squeezing properties of light field in this system are studied. The results show that two quadrature components of light can be squeezed periodically. The maximum depth of squeezing is determined by the interaction intensity between light field and atoms and the initial squeezing factor of light, and squeezing period is correlated with the frequency of the light field.
Triple differential cross section for the ionization of Ar(3p) by low-energy electron impact in the coplanar asymmetric geometry
Authors: Zhang Han-Jun  , Shan Xu  , Xu Chun-Kai  , Chen Xiang-Jun  ,   Hefei National Laboratory for Physical Sciences at the Microscale, Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

(e, 2e) triple differential cross sections for the ionization of Ar (3p) by 70.8 eV electron impact are calculated in the coplanar asymmetric geometry using the modified distorted-wave Born approximation, and compared with the recent experimental data of Ren et al. [Ren et al. 2012 Phys. Rev. A 85 032702]. The results show that electron exchange effect and post-collision interaction play an important role in the (e, 2e) process of low-energy electron impact.
Macroscopic effects in stimulated Raman spectra
Authors: Pei Li-Ya  , Zuo Zhan-Chun  , Wu Ling-An  , Fu Pan-Ming  ,   Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

In stimulated Raman gain and loss spectra with the D1 line of an Rb85 atomic vapor system we observe experimentally that as the detuning of the pump field becomes larger, a probe beam can exhibit a sharp transition from gain to loss. We use the dressed-state model to explain this phenomenon as the consequence of polarization interference between atoms of different velocities, which have competing contributions to the probe beam.
Supercontinuum generation based on all normal dispersion photonic crystal fiber
Authors: Liu Shuang-Long  , Chen Dan-Ni  , Liu Wei  , Niu Han-Ben  ,   College of Opto-Electronic Engineering, Shenzhen University, Shenzhen 518060, China
Published: December 2020

Evolutions of ultrashort pulse in time and frequency domain are modeled based on the nonlinear schrödinger equation by predictor-corrector split-step flourier method when the pulse travels in an all normal dispersion photonic crystal fiber. And the influences of the pulse duration and energy on generated continuum are also investigated. It is shown that a single pulse is maintained in the time domain and that a larger spectrum broadening is achieved with higher peak power. When the fiber is pumped by an unchirped Gaussian pulse centred at 1060 nm with duration about 50 fs and energy 1.5 nJ, good continuum is available after only 12 cm traveling distance with fine continuity and coherence. And a perfect continuum is achieved with duration about 15 fs and spectrum about 700 nm after pulse compression by a pair of prisms.
Novel bend-resistant large-mode-area photonic crystal fiber with a triangular-core
Authors: Wang Xin  , Lou Shu-Qin  , Lu Wen-Liang  ,   School of Electronic and Information Engineer, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

A novel bend-resistant large-mode-area photonic crystal fiber with a triangular-core is proposed in this paper. In this structure, the circle air holes with uniform size are used to reduce the difficulty in fabrication. At a wavelength of 1.064 μm, mode field area of the fundamental mode is 1386 μm2 in a straight state, and it is 1153 μm2 at a bending radius of 30 cm. The decrement of mode field area in a bent state is only 16.85% compared with that in a straight state. When a bending radius is 30 cm, bending loss of the fundamental mode is 0.087 dB/m while bending loss of the second order mode is higher than 1.5 dB/m. The bending loss difference between fundamental mode and second order mode is large enough to ensure that the fiber conforms to the single mode operation conditions. Furthermore, when the fiber is bent with a bending radius of 30 cm, the bending orientation angle can be extended to ±180°, breaking the limit of the bending orientation. The fiber with large mode area, small decrement in mode field area, low bending loss and low sensitivity of bending orientation makes a great contribution to the miniaturization of high power fiber laser and fiber amplifier.
A selective mapping peak-to-average power ratio reduction algorithm without side information for underwater acoustic multiple-input multiple-output orthogonal frequency division multiplexing communication
Authors: Wang Wei  , Qiao Gang  , Xing Si-Yu  ,   Science and Technology on Underwater Acoustic Laboratory, Harbin Engineering University City, Harbin 150001, China
Published: December 2020

To overcome the disadvantage of side information transmission, an improved selective mapping algorithm is proposed for peak-to-average power ratio reduction of multiple-input multiple-output orthogonal frequency division multiplexing communication via underwater acoustic channels. The scrambling patterns are carried by comb pilot with different distributions. And taking advantage of neritic channel sparse characteristics, the scrambling patterns can be distinguished without side information. The results of experiment performed with numerical simulation and tank demonstrate that the proposed algorithm can distinguish between scrambling patterns without degrading the performance, abate the burst noise effect, and significantly enhance the quality of the system.
Solution and analysis of non-Fourier heat conduction in a plane slab under arbitrary periodic surface thermal disturbance
Authors: Zhao Wei-Tao  , Wu Jiu-Hui  ,   School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China;,   State Key Laboratory for Strength and Vibration of Mechanical Structres, Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

In this paper, the non-Fourier heat conduction in a plane slab under arbitrary periodic surface thermal disturbance is solved analytically. Hyperbolic heat conduction equation is employed to describe this problem involving high-rate change of temperature. Firstly, when the plane slab surface is subjected to a sudden heat flux change or a harmonic heat flux change, the analytic solution of this problem is found by using the separation of variables method and Duhamel’s principle. On this basis, when the plane slab surface is subjected to an arbitrary periodic heat flux change, the analytic solution of temperature field is obtained by using the Fourier series and the principle of superposition. Using the obtained analytical solution, the temperature profiles of the plane slab are analyzed, and the differences between the temperature response obtained by using non-Fourier heat conduction model and that obtained by using Fourier model are discussed. This solution can be applied to more realistic periodic boundary conditions in technology.
Theoretical and experimental investigation on aero-optical effect for a compressible mixing layer
Authors: Gan Cai-Jun  , Li Lang  , Ma Han-Dong  , Xiong Hong-Liang  ,   China Academy of Aerospace Aerodynamics, Beijing 100074, China
Published: December 2020

Using dimensional analysis and experimental technique, the aero-optical effect for a compressible mixing layer around optical side window is investigated. According to the theoretical analysis, we find that time-averaged boresight error increases with the increase of convective Mach number (Mc). Moreover, we also present the relations between time-averaged boresight error (BSE) and Reynolds number, shear stress at interface between mixing layer and free stream, free stream velocity ratio and density ratio. The experimental results from a thin beam light passing through compressible mixing layer verify the theoretical result between time-averaged BSE and Mc.
Interface effects on helium retention properties of ZrN/TaN nano-multilayers
Authors: Wang Fei  , Liu Wang  , Deng Ai-Hong  , Zhu Jing-Jun  , An Zhu  , Wang Yuan  ,   Key Laboratory for Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China;,   Department of Physics, Sichuan University, Chengdu 610064, China
Published: December 2020

In this paper, ZrN/TaN nano-multilayers are fabricated in mixing atmosphere by radio frequency magnetron sputtering. The phase structures, He-related defects, helium content and cross-section morphologies of ZrN/TaN nano-multilayers are characterized by X-ray diffraction, slow positron beam analysis, enhanced proton backscattering spectrome and scanning electron microscope, respectively. The results show that the interface of ZrN/TaN nano-multilayer with 30 nm modulation period is stable and could resist the damage of helium even annealed at 600℃. The He retention rate of ZrN/TaN nano-multilayer with 30 nm modulation period can reach up to 45.6%.
Magnetism of V, Cr and Mn doped MoS2 by first-principal study
Authors: Cao Juan  , Cui Lei  , Pan Jing  ,   Basis Department of Suqian College, Suqian 223800, China;,   College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China
Published: December 2020

According to density functional theory of first-principles calculations theory, we systematically study the electronic structures, magnetisms and stabilities of transition metal (TM = V, Cr, Mn) doped MoS2 single-layers. The results show that V-and Mn-monodoped systems each have magnetism and the magnetic moment mainly concentrates on the transition metal dopant atom, but Cr-doped MoS2 does not display magnetism. Further study on the magnetic coupling of double atoms doped MoS2 shows that the stable ferromagnetic state at room temperature is observed in the Mn-doped MoS2. However, the system shows a non-spin polarization state due to doping with V. The calculated formation energy indicates that the Mn-doped MoS2 is the most stable system. Therefore, Mn-doped single-layer MoS2 maybe have potential applications in the spin electronic devices due to its good ferromagnetism and reliable stability.
Optical absorptions in monolayer and bilayer graphene
Authors: Chen Ying-Liang  , Feng Xiao-Bo  , Hou De-Dong  ,   School of Physics and Electronic Information Technology, Yunnan Normal University, Kunming 650500, China
Published: December 2020

We theoretically simulate one-photon and two-photon absorption spectra for monolayer and bilayer graphene employing the second-order perturbation theory of the electron-photon interaction. The tight-binding model is used to describe the band structure of graphene. The results show that one-photon absorption coefficient of monolayer graphene is a constant about 6.8×107 m-1, demonstrating that the absorptivity of incident light in monolayer graphene approximates to 2.3%. The one-photon absorption coefficient of bilayer graphene changes sectionally with the wavelength and is greater than that of monolayer graphene. The two-photon absorption coefficient of monolayer graphene is proportional to λ4. The two-photon absorption coefficient of bilayer graphene exhibits a giant resonance absorption peak in the infrared (～ 3100 nm) region. Our results will provide theoretical guidance for the application of graphene in the research field of optoelectronic devices.
Study on internal short-range order microstructure characteristic of SiO2 thin film
Authors: Liu Hua-Song  , Ji Yi-Qin  , Jiang Yu-Gang  , Wang Li-Shuan  , Leng Jian  , Sun Peng  , Zhuang Ke-Wen  ,   Tianjin Key Laboratory of Optical Thin Film, Tianjin Jinhang Institute of Technical Physics, Tianjin 300192, China
Published: December 2020

SiO2 is one of important low refractive index materials, and SiO2 films are prepared by both ion-beam sputtering (IBS) and electron-beam evaporating (EB) technology. Dielectric constants of SiO2 films are calculated by infrared spectrum inversion technique in a wavenumber range from 400 cm-1 to 1500 cm-1. Through analyzing dielectric energy loss function, the oscillation frequency and the Si–O–Si angle of two types of SiO2 films are obtained in the transverse optics and longitudinal optics oscillating mode. The research results indicate that the attended modes of SiO4 are main coesite-like structure, three-plane folding ring structure, and keatite-like structure in the range of short-range order for EB-SiO2 films, but the attended modes of SiO4 are main coesite-like structure, three-plane folding ring structure, four-plane folding ring structure, and keatite-like structure in the range of short-range order for IBS-SiO2 films.
Effect of high-energy electron exposure on the charge states of defects in diamond
Authors: Tian Yu-Ming  , Wang Kai-Yue  , Li Zhi-Hong  , Zhu Yu-Mei  , Chai Yue-Sheng  , Zeng Yu-Shun  , Wang Qiang  ,   School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China;,   Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
Published: December 2020

A great number of point defects are created in diamond by electron irradiation, most of which are charged. In this paper, we come up with an interesting thought to determine the charge states of these defects in diamond. The irradiated regions are exposed by high-energy electrons with a scanning electron microscopy (SEM), and then are characterized by the low temperature micro-photoluminescence (PL) technology. Some evidences to determine the charge states of defects are obtained by comparing the PL spectra between the cases with and without SEM exposure.
Simulation study of the influence of ionizing irradiation on the single event upset vulnerability of static random access memory
Authors: Ding Li-Li  , Guo Hong-Xia  , Chen Wei  , Yan Yi-Hua  , Xiao Yao  , Fan Ru-Yu  ,   Northwest Institute of Nuclear Technology, Xi’an 710024, China;,   Department of Engineering Physics, Tsinghua University, Beijing 100084, China
Published: December 2020

Single event upset vulnerabilities of static random access memory (SRAM) cells on the micron scale and deep sub-micron scale are characterized and analyzed under ionizing irradiation. Meanwhile, by means of three-dimentional simulation, electrical responses of 6-T SRAM cell with feature size 0.18 μm are calculated when ions are injected into the different central single transistors under the irradiotion with different deposited doses. The simulation results are consistent with the analysis conclusion: the single event upset vulnerability would increase only when the SRAM cell stores the same state as the one stored in the irradiation period.
Analysis of electrical property parameters of CdS/CdTe solar cells fabricated by close space-sublimation
Authors: Zhao Shou-Ren  , Huang Zhi-Peng  , Sun Lei  , Sun Peng-Chao  , Zhang Chuan-Jun  , Wu Yun-Hua  , Cao Hong  , Wang Shan-Li  , Chu Jun-Hao  ,   National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China;,   Shanghai Center for Photovoltaics, Shanghai 201201 China
Published: December 2020

CdS/CdTe Thin film solar cells are grown in a homemade close-space sublimation system where the cell fabrication of p-n junction is carried out in a continuous, in-line process. The best efficiency achieved is about 11% (AM1.5). Another cell is prepared with the same procedure except for the n-CdS layer coated by sputtering(SP), achieving an efficiency of about 10% (AM1.5). Current density-voltage and external quantum efficiency measurements are analyzed and the solar cell performances are characterized. By the comparison between the practical fitted data and theoretical calculations, the method of improving CdS/CdTe solar cell efficiency, i.e., increasing the open-circuit voltage (Voc), short circuit current (Jsc), and fill factor (FF), is proposed.
A new approach to abrupt change detection based on Fisher information
Authors: Cai Shu-Ping  , Dai Li  , Ni Hao  ,   College of Electrical Information and Engineering, Jiangsu University, Zhenjiang 212013, China;,   Key Laboratory of Facility Agriculture Measurement and Control Technology and Equipment of Machinery Industry, Jiangsu University, Zhenjiang 212013, China
Published: December 2020

The dynamics structure of many complex system there often happens a suddenly change due to the effect of outside force in nature. This abrupt change is closely related to human life. In order to make an accurate prediction of abrupt change and take corresponding measures, abrupt change should be detected effectively. Fisher information (FI) can keenly catch and characterize a small change in probability density distribution (PDD) of a system variable. While there is a change in dynamic structure of a system, the PDD of the system variable will have some changes correspondingly. In view of this, in this paper we describe in detail that FI is used to detect and recognize the abrupt change of system dynamics structure, and it is a new method to solve the detection of abrupt change in dynamic structure of a system. First of all, this method is used to present the ability to detect abrupt change lying in ideal datasets of different types of ideal signals. Next, this method is used to analyze daily datasets of ground climate from national meteorological information center of China meteorological administration between 1960 and 2008 in Lanzhou meteorological observation station in Northwest area. The results show that the daily datasets are consistent with historical records, which further verifies that the method is effective and practical.
Gradient-based response surface approximations for design optimization
Authors: Luo Jia-Qi  , Liu Feng  ,   College of Engineering, Peking University, Beijing 100871, China;,   Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA 92697-3975, USA
Published: December 2020

This paper presents a gradient-based response surface (GBRS) model and its applications to the aerodynamic design optimization. Since the widely used polynomial response surface model is continuous and differentiable, the gradients of the original response can be involved in constructing the quadratic polynomial response surface model. For the quadratic GBRS model, the number of the required samples depends linearly, instead of quadratically on the number of design parameters. Firstly, the samples are determined through the modified design of experiment with shortened sampling time to construct the GBRS model. Then function experiments are performed to evaluate the accuracy of GBRS model and its effectiveness in searching for the global minimum. Finally the gradients for constructing the GBRS model are calculated by the adjoint method and then an inverse design and an optimization design for improving the efficiency of a cascade are performed based on the GBRS model and the complex method. Results demonstrate that the optimization method based on the GBRS model is feasible and effective for obtaining the global optimum with high optimization efficiency; and the aerodynamic performance of the cascade can be significantly improved.
Parameter identification in chaotic systems by means of quantum particle swarm optimization
Authors: Zhang Hong-Li  , Song Li-Li  ,   Xinjiang University, Department of Electrical Engineering, Urumqi Xinjiang 830047, China
Published: December 2020

Aiming at the parameter identification problem in chaotic systems, we propose the quantum particle swarm optimization algorithm based on the swarm intelligence particle swarm optimization. The test functions show that the method has good global optimization. Then the method is applied to the parameter identification problem of the chaotic system. We transform the parameter identification problem into the optimization in the multi-dimensional function space. Through research on the balance board thermal convection in a typical chaotic Lorenz system, the proposed method has been compared with the basic algorithm and the genetic algorithm. Simulation results show that the proposed algorithm is effective, and is very important to the development of chaos theory.
Molecular dynamical simulations of the melting properties of Aln(n=13–32) clusters
Authors: Li Chun-Li  , Duan Hai-Ming  , Kerem Mardan  ,   College of Physical Science and Technology, Xinjiang University, Urumqi 830046, China
Published: December 2020

Based on the Gupta-type semi-empirical inter-atomic many body potential, the melting properties of Aln(n=13–32) clusters are systematically investigated by using the molecular dynamics method combined with the simulated annealing and quenching techniques. Our results show that, except for several sizes (Al13 and Al19), in general the heat capacity curves all are in disorder (no obvious single-peak), which are consistent with the experimental observations that small aluminum clusters have messy heat capacity curves in the melting process. Reasons for the different melting behaviors (whether they exhibit regular or irregular heat capacity curves) of these small Al clusters can be explored by analyzing the energy distributions of the simulated quenching structures of these clusters at different temperatures. For the clusters with disordered heat capacity curves one can obtain the melting points from analyzing the atomic equivalence indexes of those clusters, and the variations of the calculated melting points of the aluminum clusters with increasing cluster size are in agreement with the experimental observations.
Investigation on the potential energy curves and spectroscopic properties of the low-lying excited states of BP
Authors: Guo Yu-Wei  , Zhang Xiao-Mei  , Liu Yan-Lei  , Liu Yu-Fang  ,   Department of Physics, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The multi-reference configuration interaction (MRCI) method in quantum chemistry is used to investigate the BP+ at the level of aug-cc-pVQZ basis set. The potential energy curves of 6 Λ-S states of BP+ radical are obtained, which can be correlated to the dissociation limit B+(1Sg)+P(4Su), B+(1Sg)+P(2Du) and B+(1Sg)+P(2Pu). In order to get the accurate potential energy curves, the Davidson correction (+Q) and scalar relativistic effect are taken into consideration. Analyses of the electronic structures of Λ-S states demonstrate that the Λ-S electronic states are multi-configurational in nature. The spin-orbit interaction is considered for the first time sofar as we have, which makes 6 Λ-S states split to 10 Ω states. The calculation results show that the crossing between the Ω states of the same symmetry can be aveided. Then the spectroscopic constants of the bound Λ-S and Ω states are obtained by solving the radial Schrödinger equation with the program LEVEL8.0 according to the MRCI wave functions. By comparing with available experimental results, the spectroscopic constants of ground states are in good agreement with the available theoretical values. The remaining computational results in this paper are reported also for the first time.
Particle swarm optimization investigation of stable structures of Pt-Pd alloy nanoparticles
Authors: Liu Tun-Dong  , Chen Jun-Ren  , Hong Wu-Peng  , Shao Gui-Fang  , Wang Ting-Na  , Zheng Ji-Wen  , Wen Yu-Hua  ,   Center for Cloud Computing and Big Data, School of Information Science and Engineeering, Xiamen University, Xiamen 361005, China;,   Institute of Theoretical Physics and Astrophysics, Department of Physics, Xiamen University, Xiamen 361005, China
Published: December 2020

Pt-Pd alloy nanoparticles exhibit better catalytic activity and selectivity than pure Pt and Pd ones, and thus to explore their stable structures is crucial for understanding the catalytic performance of nanoparticles. In this paper, the particle swarm optimization algorithm and the quantum Sutton-Chen potentials are employed to investigate the stable structures of tetrahexahedral Pt-Pd alloy nanoparticles with different sizes and different composition. Results show that in Pt-Pd alloy nanoparticles, Pt atoms are preferential to locate of the core and Pd atoms to occupy the surface. Furthermore, the more symmetrical and ordered the structure, the lower the energy of the structure. The Warren-Cowley chemical short-range order parameters of three different sizes of nanoparticles increase accordingly with rising fraction Pt. The segregation degree of small sized nanoparticle is more remarkable than large sized one for the same content of Pt.
Use of lattice Boltzmann method to simulate 2-D partial differential equation
Authors: He Yu-Bo  , Lin Xiao-Yan  , Dong Xiao-Liang  ,   Department of Mathematics, Huaihua University, Huaihua 418008, China;,   School of Information and Computation Science, The North University for Ethnics, Yinchuan 750021, China
Published: December 2020

For a class of two-dimensional nonlinear partial differential equation with the source term,a simple lattice Boltzmann model with amending function is proposed and studied using the Chapman-Enskog expansion technique and multiple-scale analysis. In this paper, some partial differential equation are simulated, the numerical results and exact solutions are shown to be almost completely fitting with each other. The lattice Boltzmann method is further extended to two-dimensional partial differential equation.
Experimental and numerical studies on “crown” spike generated by a bubble near free-surface
Authors: Li Shuai  , Zhang A-Man  , Wang Shi-Ping  ,   School of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China
Published: December 2020

Strong interaction between bubble and free-surface will cause complex phenomena, producing many different types of spike. Based on potential flow theory, a numerical model was established to simulate the crown spike. A downward jet was formed during the bubble’s collapsing, and simulation of the free-surface was continued regard less of the ring bubble’s effect on it. Simulation results show good agreement with the experiment conducted with a high speed camera and a spark-generated device, and the relative error was less than 10%. Some special phenomena were found through numerical calculation, such as apron-shrink and peak-dropped. Finally, the effects of initial condition and Weber number on crown-type water column were studied.
Numerical simulation of nanosecond laser ablation impulse coupling
Authors: Chang Hao  , Jin Xing  , Chen Zhao-Yang  ,   State Key Laboratory of Laser Propulsion & Application, the Academy of Equipment, Beijing 101416, China;,   Department of Physics, Beijing University of Chemical Technology, Beijing 100029, China
Published: December 2020

To investigate the process and mechanism of the impulse generation of laser ablation target, a comprehensive model including one-dimensional heat conduction and fluid dynamics is developed. The target Al, the most common space debris material, is used based on the proposed numerical model in the calculation of ns laser pulse ablation impulse and impulse coupling coefficient as a function of time. Numerical results agree well with experimental data available. Numerical simulations show that, during the laser pulse the impulse the target gained increases greatly with time; after the laser pulse terminates, the impulse tends to be stable with time. In the process of laser impulse coupling, the laser ablation plasma expands into vacuum and its size also gradually increases; meanwhile the plasma plume absorbs the incident laser energy and leads to the reduction in the laser energy deposited onto the target.
PIC/MCC simulation of the ionization process of SWP influenced by gas pressure and SPP
Authors: Chen Zhao-Quan  , Xia Guang-Qing  , Liu Ming-Hai  , Zheng Xiao-Liang  , Hu Ye-Lin  , Li Ping  , Xu Gong-Lin  , Hong Ling-Li  , Shen Hao-Yu  , Hu Xi-Wei  ,   College of Electrical & Information Engineering, Anhui University of Science and Technology, Huainan 232001, China;,   State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China;,   State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

A surface-wave plasma (SWP) source based on surface plasmon polariton (SPP) has fine performances such as high density, low temperature, high production, and so on. It is applied in electronic device micro or nano processing, material modification, etc. Because the ionization of SWP heated by SPP is difficult to describe by theoretical analysis and experimental measurement, the ionization process of producing uniform stable SWP source is not yet well understood. The method in this paper is a numerical simulation of SWP discharges. The electromagnetic energy coupling mechanism of ionization process, influenced by gas pressure, which is studied by combining particle-in-cell (PIC) simulation of reciprocity between plasma and electromagnetic wave with Monte Carlo Collide (MCC) method in merit of dealing with particle collision. Simulated results suggest that the efficient production of SWP is induced by locally enhanced electric field of SPP, and the gas pressure influences the ionization process of SWP by altering the appearance time of wave-mode resonant conversion. Results of this paper show the ionization process of SWP discharge maintained by SPP, and further provide some advices for designing the parameter optimization of next generation meter-scale SWP source.
A track study on icosahedral clusters inherited from liquid in the process of rapid solidification of Cu64Zr36 alloy
Authors: Wen Da-Dong  , Peng Ping  , Jiang Yuan-Qi  , Tian Ze-An  , Liu Rang-Su  ,   School of Material Science & Engineering, Hunan University Changsha 410082, China
Published: December 2020

The rapid solidification process of liquid Cu64Zr36 alloy is simulated using a molecular dynamics method. The evolution in micro-structures are analyzed by means of pair distribution functions (PDF), Honeycutt-Andersen (H-A) bond-type index method and cluster-type index method (CTIM). It is found that both of liquid and rapidly solidified solid mostly consist of (12 0 12 0) icosahedra and their distorted (12 8/1551 2/1541 2/1431) configurations at a cooling rate of 50 K/ns, most of which are Cu-centered Cu8Zr5 clusters, followed by Cu7Zr6 and then Cu9Zr4 clusters. Size distribution of icosahedral medium-range order (IMRO) clusters linked by intercross-sharing (IS) atoms in the liquid and the glassy solid presents the magic number sequences of 13, 19, 25,···and 13, 19, 23, 25, 29, 37···, respectively. The track of atoms reveals no icosahedral clusters in rapidly solidified solid that can be detected in the liquid alloy. Onset temperature of configuration heredity emerges in the supercooled liquid region of Tm–Tg. A direct and perfect heredity of icosahedra is found to be dominant and a distinct ascent in heredity fraction takes place at Tg. Compared with (12 8/1551 2/1541 2/1431) distorted icosahedra, (12 0 12 0) standard icosahedra are of high structural stability and configurational genetic ability below Tg, whereas only a few can keep their chemical composition unchanged. By partial heredity, even some IMRO clusters in super-cooled liquid can be transmitted to glassy alloy.
Capacitance characteristics of atomic layer deposited Al2O3/n-GaN MOS structure
Authors: Yan Da-Wei  , Li Li-Sha  , Jiao Jin-Ping  , Huang Hong-Juan  , Ren Jian  , Gu Xiao-Feng  ,   Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education), Department of Electronic Engineering, Jiangnan University, Wuxi 214122, China
Published: December 2020

The Ni/Au/Al2O3/n-GaN metal-oxide-semiconductor structure with circular transparent electrode has been fabricated by using atomic layer deposition technique. Effects of ultra-violet (UV) light illumination on the capacitance characteristics and deep interface states are analyzed. Physical origin of bias-induced capacitance drop in the accumulation region of some non-ideal devices is explored. Due to the extremely long electron emission time and the extremely slow minority carrier generation rate, a typical deep depletion behavior can be observed in the dark room-temperature capacitance-voltage sweep curve, and the deep-level interface state occupancy above the electron quasi-Fermi level remains unchanged. Under the UV illumination, photo-induced holes will empty the deep interface traps above the electron quasi-Fermi level, and also de-charge the deep donor-like traps in the oxide layer. The anomalous capacitance drop in the accumulation region is attributed to the bias-dependent excessive leakage conductance across the dielectric layer, which might be induced by a charge-to-breakdown process related to electrical traps in the oxide and the inferior interface quality.
Highly efficient all fluorescent white organic light-emitting devices made by sequential doping
Authors: Wu Qing-Yang  , Xie Guo-Hua  , Zhang Zhen-Song  , Yue Shou-Zhen  , Wang Peng  , Chen Yu  , Guo Run-Da  , Zhao Yi  , Liu Shi-Yong  ,   State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China;,   Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, Fife KY16 9SS, UK
Published: December 2020

Highly efficient all fluorescent white organic light-emitting devices (WOLED) have been fabricated by means of sequential doping. Fluorescent materials PT-01, PT-86 and PT-05 serve as the yellow guest, blue guest and fluorescent host, respectively. The emission layer consists of a few repeating cells, which are made of sequentially evaporated host and guest layers. From the analyses of the singlet exciton distribution and the influences of the thickness of the host layer, PT-86 and PT-01 are evaporated at the proper locations in the emission layer (EML), yielding a high efficiency and stable all fluorescent WOLEDs. The maximum current efficiency of the WOLED is 11.2 cd/A. In addition, the emission color of this WOLED is fairly stable, consistent with the Commission International de L’Eclairage coordinates, only showing changes (±0.004,±0.005) when luminance increasing from 159 cd/m2 to 20590 cd/m2. The devices based on the method of sequential doping not only have the similar performance compared with that fabricated by co-evaporation doping, but also have higher repeatability, which makes them appropriate for mass-production.
Design and study of the polarization selective surface based on the complementary screens
Authors: Jiao Jian  , Gao Jin-Song  , Xu Nian-Xi  , Chen Xin  ,   Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Based on the strong coupling of the complementary frequency selective surface (CFSS), a frequency selective surface with polarization selective performance is presented. When there is lateral displacement along the periodic arrangement direction between the capacitive surface and the inductive surface, the CFSS becomes the polarization selective surface (PSS) with TM pass-band and TE stop-band filtering characteristics. The equivalent circuit model of the PSS is used to analyze its polarization selective mechanism. Its frequency responses and the electric field distribution on the capacitive and inductive surfaces have been simulated by the coupled integral equation method. The simulated and experimental results show that the PSS has good polarization selectivity, and it provides reference for the design of polarization wave generator and polarization filter.
Fabrication of ordered Au nanoparticles array and its optical absorption properties
Authors: Li Rao  , Zhu Ya-Bin  , Di Yue  , Liu Dong-Xue  , Li Bing  , Zhong Wei  ,   School of Science, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

Three kinds of polystyrene spheres with different sizes were fabricated on glasses by drifting method of nanosphere lithography. Au thin films with various thicknesses were prepared by magnetron sputtering under controlled deposition time. Triangle-shaped Au nanoparticles array in three different heights after removing the PS template were observed using scanning electron microscopy. The absorption characteristics of all samples were measured by ultraviolet-visible spectrophotometer. Surface plasmon resonance peak was seen to shift to the longer wavelength with increasing diameter of Au nanoparticles. And the surface plasmon resonance peak was shifted to the shorter wavelength with increasing height of Au nanoparticles. Based on Mie theory, we simulated the extinction properties, which vary with the diameter of Au nanoparticles, using Matlab software. The conclusion is in accordance with our experimental results.
Study on atomic layer deposition preparation of core-shell structured nanometer materials
Authors: Li Yong  , Li Hui-Qi  , Xia Yang  , Liu Bang-Wu  ,   Shandong University of Science and Technology, Shandong 266590, China;,   Key Laboratory of Microelectronics Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
Published: December 2020

Monocrystal Pt nanoparticles, amorphous Al2O3 thin film, polycrystalline ZnO and TiO2 thin films were fabricated on black carbon nanoparticles by means of atomic layer deposition (ALD). Using high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectrometer (XPS), energy dispersive spectroscopy (EDS), We have characterized and analyzed the surface morphology, crystal structure and composition of the ranopasticles and thin filins. Results indicate that the ALD method is an ideal method to prepare core-shell stuctured nanometer materials. In addition, the reasons why the formation of ALD films with different crystal morphologies, such as monocrystal, amorphous, polycrystalline, were discussed.
Low temperature synthesis of manganese cobalt nickel oxide thin film by alcohol-thermal reaction
Authors: Chen Xue-Ying  , Xu Jin-Bao  , Bian Liang  , Wang Lei  , Xiong Xin-Qian  , Gao Bo  ,   Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China;,   University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

Manganese cobalt nickel complex oxide is a thermal-sensitive material with the property of semiconductor. In this paper, Mn1.74Co0.72Ni0.54O4 (MCN) thin film was prepared in air using metal-organic-deposition method at room temperature on Si substrate, and the crystallization synthesis of the MCN thin film was prepared using alcohol-thermal reaction. According to X-ray diffraction, field emission scanning electron microscope (FESEM) and the relationship between resistivity and temperature, effects of MCN thin film made by alcohol-thermal reaction on crystalline microstructure, surface morphology and electrical properties were investigated. X-ray diffraction pattern showed that the MCN thin film appears to be spinel structure with predominant spinel peaks. Field emission scanning electron microscope showed that the surface morphology of MCN thin film is crack-free and compact surface. The relationship between resistivity and temperature of the thin film Mn1.74Co0.72Ni0.54O4 was that the resistivity decreases with the increase in temperature. The room temperature(≈ 27℃) resistivity of the MCN thin film was 303.13 Ω·cm.