bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of charging, motion and temperature of dust particulates in magnetic fusion devices
Authors: Liu Jin-Yuan  , Chen Long  , Wang Feng  , Wang Nan  , Duan Ping  ,   (1)College of Physics Science and Technology, Dalian University, Dalian 116622, China; (2)School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
Published: December 2020

Characteristics of dust particulates (charging, movement and temperature) in magnetic fusion devices with different plasma parameters are discussed. It is shown that the charge quantity of dust particulates is obviously influenced by the ratio between electron and ion temperatures; secondary electron emission reduces the charge quantity; the charging relaxation time of dust particulates in fusion plasma is much shorter than in laboratory plasma; dust particulates speed reach hundreds of meters per second under the action of ion drag force; the lifetime of carbon dust in fusion plasma is on the millisecond scale. The results are consistent with experimental observations.
Chaotic property analysis and prediction model study for heating load time series
Authors: Zhang Yong-Ming  , Qi Wei-Gui  ,   Department of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

In order to reveal the internal dynamics characteristics of heating load time series, the existing chaotic behavior is validated by use of nonlinear analysis method. The data sets taken from heat source and substation of district heat supply are studied by which phase spaces are reconstructed, and the correlation dimensions and the largest Lyapunov exponent are computed to identify the presence of chaos in heat load time series. By the analysis of the results, chaotic characteristics obviously exist in the heat load time series, which is a theoretical basis for the correlative investigation of heat load prediction. According to the existing heat load predictive method almostly based subjective models, a novel predictive approach based on Volterra adaptive filter, which avoids the subjective model assumptions, is presented for heat load prediction. Finally the predictive results are presented, and the simulation results illustrate that the second-order Volterra adaptive filter has high predictive accuracy which can meet the demands of heat energy-saving control and heat dispatching in practical applications.
Study of the femtosecond fiber comb and absolute optical frequency measurement
Authors: Meng Fei  , Cao Shi-Ying  , Cai Yue  , Wang Gui-Zhong  , Cao Jian-Ping  , Li Tian-Chu  , Fang Zhan-Jun  ,   Istitute of Quantum Electronics, School of Electromnics Engineering and Computer Science, Peking University, Beijing 100871,China;,   Division of Electronics and Information Technology, National Institute of Metrology, Beijing 100013, China
Published: December 2020

An optical frequency comb is built by using a commercial femtosecond laser and signal-noise (S/N) ratio of the fceo signal is obtained to be about 30 dB. Its repetition rate frequency and offset frequency are highly stable and the tracking stability is verified. An absolute frequency measurement of a 1064 nm Nd: YAG laser is realized by using this stabilized optical frequency comb. The tracking stability of the repetition rate frequency is superior to 3.710-14 at 100 s and the absolute frequency of the laser is 281630111757362 Hz. The experimental result is in accordance with the recommended value by International Committee of Weights Measures(CIPM).
Design and study of high birefringent terahertz photonic crystal fiber with hybrid crystal lattice
Authors: Wang Jing-Li  , Yao Jian-Quan  , Chen He-Ming  , Bing Pi-Bin  , Li Zhong-Yang  , Zhong Kai  ,   Institute of Laser and Optoelectronics, College of Precision Instrument and Optoelectronic Engineering, Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Tianjin University, Tianjin 300072, China;,   College of Optoelectronic Engineering, Institute of Optical Communications, Nanjing University of Posts and Telecommunications, Nanjing 210003,China
Published: December 2020

In this paper, we propose a novel high birefringent terahertz (THz) photonic crystal fiber (PCF) with subwavelength circular air hole pairs in the core which are arranged as a hybrid crystal lattice structure. And its high mode birefringence is realized by reducing structure symmetry in core. A professional software COMSOL Multiphysics 4.0 is used for modeling, and the simulation results show that this kind of THz PCF exhibits a high birefringence on a level of 10-2and low confinement loss over a wide THz frequency range. Moreover, the birefringence or confinement loss can be controlled flexibly by adjusting some fiber parameters. Compared with a similar structure PCF for the optical communication, the THz PCF is easier to practically fabricate, owing to its large wavelength size.
Stochastially re-sorting detrended fluctuation analysis: a new method to define the threshold of extreme event
Authors: Hou Wei  , Zhang Da-Quan  , Zhou Yun  , Yang Ping  ,   National Climate Center, Beijing 100081, China;,   Key Laboratory of Regional Climate Environment Research for Temperature East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;,   College of Physical Science and Technology, Yangzhou University, Yangzhou 225002, China;,   Institute of Urban Meteorology of Beijing, China Metrology Administration,Beijing 100089, China
Published: December 2020

By combining detrended fluctuation analysis (DFA) method with surrogate data method, and using the Heuristic segmentation algorithm as well as Chi-Square statistics, we develop a new method to determine the threshold of extreme events, e.g. stochastically re-sorting detrended fluctuation analysis (S-DFA) method. The S-DFA method has a certain phsical background, when the occurrence rate of the data is small, then these data belong to little-probability events and they contain so little information about the dynamic system, the states corresponding to these data are abnormal states or extreme states of the system. When the occurrence rate of the data is large or even in distribution these data do not belong to little-probability events and they contain much information about the system, the states corresponding to these data are normal states of the system. Compared with the Percentile curves method, the S-DFA method gives the critical value between extreme event and non-extreame event, which is definite and unique. We also extensively validate the effectiveness of S-DFA method through extreme event detection.
Realization of the discrete chaotic system based on SET-MOS circuits
Authors: Feng Chao-Wen  , Cai Li  , Kang Qiang  , Peng Wei-Dong  , Bai Peng  , Wang Jia-Fu  ,   College of Science, Air Force Engineering University, Xi’an 710051, China;,   Department of Science Research, Air Force Engineering University, Xi’an 710051, China;,   Research Center of Integrated Electronic Information System, Air Force Engineering University, Xi’an 710051, China
Published: December 2020

A new method of realizing a discrete chaotic system using the hybrid architecture of single-electron transistor (SET) and metal oxide semiconductor (MOS) is proposed in this paper. The transfer characteristic for two parallel SETs with a biased current source is investigated and the corresponding S-shape piecewise linear function model is established. Based on this model a one-dimensional discrete mapping system is first constructed, and the dynamics of the system is then analyzed through one-dimensional mapping process bifurcation diagram and Lyapunov exponents, and the corresponding discrete chaotic system is finally designed through the electronic circuit of SET-MOS hybrid architecture. All these indicate that our approach not only is feasible but also has some advantages such as simple circuit structure and good integration compared with existing methods.
Optical characterization of neutron detection crystal Li6Gd(BO3)3:Ce
Authors: Yang Fan  , Pan Shang-Ke  , Ding Dong-Zhou  , Wu Yun-Tao  , Ren Guo-Hao  ,   Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, China
Published: December 2020

Colorless and transparent Li6Gd(BO3)3:Ce crystals are grown with the Czoralski method. Their optical characteristics and luminescence processes are also investigated. The ultraviolet-vaccum ultraviolet (UV-VUV) transmittance spectra are measured and the result shows that absorption peaks due to Ce3+ ions and Gd3+ ions, and the absorption band related to charge transfer band of Ce4+ ions are present. According to the UV-VUV excitation and emission spectra, it is found that there appear luminescences of 5d4f radiative transitions of Ce3+ ions and of 4f4f radiative transitions of Gd3+ ions, and also Gd3+Ce3+ energy transfer. The X-ray and -ray stimulated luminescence spectra show that the scintillation light of the crystal is mainly from Ce3+ ions.
Design and simulation of chiral negative refractive structure based on folded-wire
Authors: Li Jie  , Yang Fang-Qing  , Wang Zhan  , Dong Jian-Feng  ,   Institute of Optical Fiber Communication and Network Technology, Ningbo University, Ningbo 315211, China
Published: December 2020

A new chiral structure working in microwave and optical frequency bands based on folded-wire is designed and simulated. Effective parameters of this structure, including polarization azimuth rotation angle, ellipticity angle, relative permittivity, relative permeability, chiral parameter and refractive index are obtained from simulated transmission and reflection spectra. The results show that the exceptionally strong polarization azimuth rotation angle and the ellipticity angle are found in microwave and optical frequency bands. Because this structure has a large chiral parameter, negative refractive index of a circularly polarized wave can be obtained without requiring permittivity and permeability to be negative simultaneously.
Multiple electromagnetically-induced transparency of hyperfine levels in cesium 6S1/2 -6P3/2 -8S1/2 ladder-type system
Authors: Yang Bao-Dong  , Gao Jing  , Wang Jie  , Zhang Tian-Cai  , Wang Jun-Min  ,   State Key Laboratory of Quantum Optics and Quantum Optics Devicecs, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China;,   College of Physics and Electronic Engineering, Shanxi University, Taiyuan 030006, China
Published: December 2020

Based on the cesium 6S1/2 -6P3/2 -8S1/2 ladder-type system, electromagnetically-induced transparency (EIT) is further investigated in a room-temperature vapor cell. When the probe laser is locked to one of the hyperfine transitions between the ground state 6S1/2 (F=3) and the intermediate state 6P3/2 while the coupling laser scans the transition between the intermediate state 6P3/2 and the excited state 8S1/2, the EIT spectrum has a flat background improving the spectral resolution. The theoretically calculated EIT spectral profiles from a multi-level ladder-type model are consistent well with the obtained experimental phenomena.
Scattering of polarized light by randomly oriented coated spheroidal particle
Authors: Sun Xian-Ming  , Wang Hai-Hua  , Shen Jin  , Wang Shu-Jun  ,   School of Electrical and Electronic Engineering, Shandong University of Technology, ZiBo 255049, China
Published: December 2020

A computer method is described to calculate the light-scattering properties of randomly oriented, axially symmetric coated particles, in the framework of the T-matrix theory. Both the core and the shell can be axially symmetric nonspheroidal particles. Based on the coated spheroidal particle model, light scattering characteristics of water aerosols with an absorptive core (black carbon) are calculated. The effects of cores with different sizes and shapes are analyzed on extinction efficiencies, scattering efficiencies, absorption efficiencies, single scattering albedos, asymmetric parameters.
Potential entransy and potential entransy decrease principle
Authors: Cheng Xue-Tao  , Dong Yuan  , Liang Xin-Gang  ,   Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
Published: December 2020

In this paper, we analyze some kinds of potential energies, such as the geopotential energy, the electrostatic potential energy, the chemical potential energy, the mass entransy and so on. It is found that they all can be expressed as the product of a conservative extensive quantity and an intensity quantity. This kind of potential energy is named potential entransy. Based on the concept of potential entransy, the potential entransy decrease principle is developed. It is found that the potential entransy of an isolated system always decreases when the extensive quantity is transferred in the system. Furthermore, the criteria of equilibrium state for an isolated system and a common closed system are derived on the basis of the concept of potential entransy. It is found that when an isolated system reaches its equilibrium state, its potential entransy is a minimum value. When a common closed system reaches its equilibrium state, its quasi-free potential entransy is also a minimum value. In addition, when a closed system with prescribed potential is in its equilibrium state, its free potential entransy is also a minimum value. When the principles above are used in heat transfer, the entransy decrease principle for heat transfer and the thermal equilibrium criteria can be developed. We think that the new physical quantity, entransy in heat transfer, is the core concept of the subject, because it can be used to describe the irreversibility of heat transfer, optimize heat transfer processes, measure the disorder degree of one system, and set up the thermal equilibrium criteria.
Optical and electrical characterization of (BiFeO3)25/(La0.7Sr0.3MnO3)25 multilayered thin films
Authors: Jiang Ping  , Si Dao-Wei  , Zhu Hui-Wen  , Li Pei-Gang  , Wang Shun-Li  , Cui Can  , Tang Wei-Hua  ,   Department of Physics, Center for Optoelectronics Materials and Devices, Zhejiang Sci-Tech University, Hangzhou 310018, China
Published: December 2020

(001) oriented(BiFeO3)25/(La0.7Sr0.3MnO3)25 multilayered thin films are fabricated on (001)SrTiO3 substrate by rf-magnetron sputtering. UV-vis absorption spectrum analysis in a photon energy range of 1.2-6.4 eV is carried out, and the result shows that in a range of 1.3-2.1 eV the absorption is enhanced compared with that on SrTiO3 substrate. And the optical band gap of BiFeO3 is around 2.7 eV, which is in accordance with other reportsed results very well. Furthermore, the current-voltage curves are measured in a temperature range of 100-300 K, and the analyses according to several dielectric conduction models exhibite that the space-charge-limited conduction is dominated in the fabricated (BiFeO3)25/(La0.7Sr0.3MnO3)25 multilayered thin films.
Superlattice patterns in a coupled two-layer Lengel-Epstein model
Authors: Bai Zhao-Guo  , Dong Li-Fang  , Li Yong-Hui  , Fan Wei-Li  ,   College of Physics Science and Technology, Hebei University, Baoding 071002, China
Published: December 2020

The influence of Turing modes in two subsystems on pattern formation is investigated by using the two-layer coupled Lengel-Epstein model. It is found that the wave number ratio between two Turing modes play an important role in the pattern formation and pattern selection. When the wave number ratio is 1, no coupling behavior occurs between two subsystems and only stripe and hexagon patterns arise in system. If the wave number ratio lies in a range of 1-√17, a variety of superlattice patterns, such as dark-dot, bar-dot and complex super hexagons, I-type or II-type white-eye, honeycomb-like, and superhexagon of circle, are obtained due to the resonance interaction between the two Turing modes in the coupled systems. When the wave number ratio is greater than √17, the superhexagon of circle is always selected and unchanged. Some superlattice patterns above, including stripes, hexagons, super hexagon, Ⅱ-type white-eye, and honeycomb-like patterns, are observed experimentally in a dielectric barrier discharge (DBD) system. In addition, the curves for variation of hexagon pattern wave number with the increase of the product of two diffusion coefficients are obtained and it is found that the wave number becomes smaller with DuDv increasing.
A stochastic functional approach to difference scattering from a three-dimensional perfect electric conductor target on randomly rough surface
Authors: Ding Rui  , Jin Ya-Qiu  ,   Key Laboratory of Wave Scattering and Remote Sensing Information of Ministry of Education, Fudan University, Shanghai 200433, China
Published: December 2020

A stochastic functional approach (SFA) is developed to calculate electromagnetic composite scattering from a three-dimensional perfectly electric conducting (PEC) target on a randomly rough PEC surface. The stochastic Green's function for randomly rough surface is derived, and a novel four-path model is presented to describe the scattering mechanism of target-surface interactions. The SFA is used to obtain the difference scattering cross section due to the rough surface of target. As a simple example of a spherical target with rough surface, the SFA is numerically compared with other numerical approaches, showing its accuracy and effectiveness. Finally, the difference bistatic scattering from a complex electric large target with rough surface and its functional dependence on the parameters are discussed.
The transmission characteristic of the multi-polarization controlled fiber loop mirror
Authors: Wang Jing  , Zhang Chen-Fang  , Kang Ze-Xin  , Sun Jiang  , Zheng Si-Wen  , Lin Zhen  , Wang Chun-Can  , Jian Shui-Sheng  ,   Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044, China
Published: December 2020

The multi-polarization controlled fiber loop mirrors (FLMs) are presented and their characteristics are studied, because of the non-tunable characteristic of the wavelength interval for single-polarization controlled FLM. The multi-polarization controlled FLMs are studied theoretically with the Jones matrix. We experimentally study the single-, double- and triple-polarization FLMs, and the results show that compared with the single-polarization controlled FLM, the multi-polarization controlled FLM possesses the interval tunability and the side-frequency restriction are shown. The experimental results are in good agreement with theoretical results. The side-frequency restriction characteristic is shown in a ring fiber laser of double-polarization FLM and the side-mode suppression ratio is enhanced by 5 dB compared with the one of single-polarization FLM.
Crystallization of water induced by fused quartz under shock compression
Authors: Li Yong-Hong  , Liu Fu-Sheng  , Cheng Xiao-Li  , Zhang Ming-Jian  , Xue Xue-Dong  ,   Institute of High Temperature and High Pressure Physics, Southwest Jiaotong University, Chengdu 610031, China
Published: December 2020

In this paper, we study the crystallization of water due to fused quartz effect under shock compression by a gas gun and light transmission tests. The experimental results indicate that at 1.28 GPa water rapid crystallizes when the water has come into direct contact with the quartz glass. On the contrary, freezing cannot occur within 2 s, demonstrating that the observed phenomenon of the liquid-solid phase transition of water can be promoted by the fused quartz. The dynamics of the phase transition is also discussed in this paper.
Organic field-effect transistor with low-cost CuI/Al bilayer electrode
Authors: Nie Guo-Zheng  , Peng Jun-Biao  , Zhou Ren-Long  ,   Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China;,   Key Laboratory of Specially Functional Materials and Advanced Manufacturing Technology of Ministry of Education,South China University of Technology, Guangzhou 510640, China;,   School of Physics, Hunan University of Science and Technology, Xiangtan 411201, China
Published: December 2020

An organic field-effect transistor based on pentacene semiconductor with CuI/Al bilayer electrode is investigated. The CuI layer, directly contacting the organic semiconductor layer, serves as the hole-injection layer. The overcoated metal layer is responsible for the reduction in contact barrier. Compared with the device with a single metal (Al, Au) layer used as the source-drain electrode, the device with CuI/Al electrodes considerably improves the hole mobility and the on/off current ratio and greatly reduces the threshold voltage. Results of X-ray photoelectron and ultraviolet/visible absorption studies reveal that the reduction in the contact barrier can be attributed to an electron transfer from pentacene and Al to CuI.
Investigation on the relation between the length of magnetic core and the giant magnetoimpedance effect of solenoid with FeCo-based magnetic core
Authors: Fang Yun-Zhang  , Xu Qi-Ming  , Zheng Jin-Ju  , Lü Bao-Hua  , Pan Ri-Min  , Ye Hui-Qun  , Zheng Jian-Long  , Fan Xiao-Zhen  ,   College of Materials Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China;,   College of Mathematics, Physics and Information Engineering, Zhejiang Normal University, Jinhua 321004, China;,   Institute of Science and Technology Information of Jinhua, Jinhua 321000, China
Published: December 2020

The relation between the length of the magnetic core (l) and the giant magnetoimpedance(GMI) effect of solenoid with magnetic core of Fe36 Co36 Nb4Si4.8 B19.2 ribbon which annealed with current 32 A/mm2 for 10 min, has been investigated. The result shows that there is a sensitive relation between l and GMI. There is a linear relation between the l and the maximum of the GMI (Z/Z)max when l is smaller than the length of the solenoid l0. The linear correlation coefficient can be deduced from the electromagnetism theory. It should deviate from the linear relation when l is greater than l0. There is a maximum value of the (Z/Z)max when the l reaches the best value. There is a similar relation between the height of the tip like part of the GMI profile (Z/Z)T and l. There is a maximum value of the (Z/Z)T when the l is the best value. The tip like part of the GMI profile, which responds to the weak magnetic field sensitively, is influenced by the demagnetizing field. There is a negative exponential relation between the demagnetizing field and the length of the magnetic core l.
Online degradation model based on process-stress accelerated test
Authors: Guo Chun-Sheng  , Wan Ning  , Ma Wei-Dong  , Xiong Cong  , Zhang Guang-Chen  , Feng Shi-Wei  ,   College of Electronic Information and Control Engineering, Beijng University of Technology, Beijing 100124, China
Published: December 2020

An online degradation model is presented, in which is avoided the error in parameter degradation accelerated test, which is caused by temperature shock during parameter measurement. Through the measurement with avoiding the error parameter, the parameter degradation model can be more accurate. To demonstrate the application of the method, a kind of mature product, 3CG120, is tested in a temperature range of 150230 ℃ under online process-stress. Then the error of lifetime is obtained by utilizing the online model to be about 6.5%, much less than that of the old model (23.2%).
The research on saturation of fast light in homogeneously broaden materials with gain
Authors: Qiu Wei  , Lü Pin  , Ma Ying-Chi  , Xu Xiao-Juan  , Liu Dian  , Zhang Cheng-Hua  ,   Department of Physics, Liaoning University, Shenyang 110036, China
Published: December 2020

According to the analysis of gain theory, the absorption or gain of medium depends on pump power. The coherent population oscillation leads the pulse to experience absorption saturation and propagation delay in a medium with absorption. This effect induces the pulse to experience gain saturation and propagation advance in a medium with gain. Making use of the transition rate equation of metastable state poplation, we develop the model of fast light in erbium-doped optical fiber and obtain the analytic expression of time advance. We demonstrate that there is a saturation effect of fast light in low frequency region, but the fast light is enhanced with pump power increasing in high frequency region.
Robust inertial terrain aided navigation algorithm
Authors: Zhao Long  ,   Science and Technology on Aircraft Control Laboratory, Beihang University, Beijing 100191, China
Published: December 2020

The traditional terrain contour matching (TERCOM) algorithm has worse reliability when velocity error or course error is larger. The extend Kalman filtering (EKF) algorithm based BUAA inertial terrain aided navigation (BITAN) algorithm fails to correctly position, leading to a decline of robustness when large initial position error or altimeter noise error occurs. In this paper, we introduce a Robust BUAA inertial terrain aided navigation (RBITAN) algorithm, which is an improved algorithm of BITAN. In the RBITAN algorithm a searching mode approach is designed by the statistic properties of mean absolute difference algorithm, mean square difference algorithm and cross correlation algorithm. The RBITAN gathers the advantages of both the TERCOM algorithm and the BITAN algorithm, and it adopts EKF based BITAN algorithm as the tracking approach. The algorithm is verified by both real digital altitude model and flight-test data. Compared with the BITAN algorithm, the RBITAN algorithm is robust, for it can achieve accurate positioning and tolerate large initial position error or altimeter noise error.
Density functional study on the geometric and electronic properties of C80H80
Authors: Cao Qing-Song  , Yuan Yong-Bo  , Xiao Chuan-Yun  , Lu Rui-Feng  , Kan Er-Jun  , Deng Kai-Ming  ,   Taizhou Institute of Science and Technology, Nanjing University of Science and Technology, Taizhou 225300, China;,   School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

The generalized gradient approximation based on the density functional theory is used to analyze the geometric and the electronic properties of C80H80. The geometric structure research indicates that between the two possible stable isomers, the isomer with 20 hydrogens connecting 12 pentagons and the 60 others outside is more stable structure. The analyses of the energy level, the orbital wavefunction, and the density of states of H20@C80H60, show that the atomic orbits of the H and C atoms have strong hybridization on the occupied molecular orbits. The low unoccupied molecular orbital of H20@C80H60 is occupied mainly by the H atoms inside the carbon cage, while the high occupied molecular orbital of H20@C80H60 are occupied partly by the H atoms outside the cage. Therefore, the H atoms inside and outside the cage will play different roles in the chemical reaction involving H20@C80H60. The H20@C80H60 shows the character of the closed-shell structures with no magnetic moment.
Influences of dislocation distribution on the resistive switching effect of Ag-SiO2 thin films
Authors: Zhang Pei-Jian  , Meng Yang  , Liu Zi-Yu  , Pan Xin-Yu  , Liang Xue-Jin  , Chen Dong-Min  , Zhao Hong-Wu  ,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

Influences of dislocation distribution on the resistive switching effect of Ag doped SiO2 thin film are investigated under different sample preparation conditions. Stable resistance switching characteristics are observed for the samples annealed at 120 ℃ and prepared in Ar/O2 mixed atmosphere. It is shown that annealing process, electric field formation and atmosphere of preparation can change the intensity and the distribution of the dislocations (Ag interstitial atoms and oxygen vacancies) in the Ag-SiO2 structure, which leads to the resistive switching effect based on the formation and annihilation of the conducting filaments.
First-principles calculation for mechanical properties of metal dihydrides
Authors: Dai Yun-Ya  , Yang Li  , Peng Shu-Ming  , Long Xing-Gui  , Zhou Xiao-Song  , Zu Xiao-Tao  ,   Department of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, China;,   Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

The mechanical properties of MH2 (M= La, Nd, Gd, Tb, Y, Dy, Ho, Er, Lu, Sc, Ti, Zr, Hf) are studied by the first-principles calculations. The results show that the fluorite structures of MH2 (M= La, Nd, Gd, Tb, Y, Dy, Ho, Er, Lu, Sc) are stable at low temperatures. Their bulk moduli, shear moduli and Young's moduli increase in the order of LaH2, NdH2, GdH2, TbH2, YH2, DyH2, HoH2, ErH2, LuH2 and ScH2. However, the cubic phases of MH2 (M= Ti, Zr, Hf) are unstable at low temperatures. According to the densities of states and charge densities of TbH2, ErH2, TiH2 and HfH2, it can be found that the stabilities of metal dihydrides depend on the interaction between metal and hydrogen atoms.
Epidemic spreading model and stability of the networks in mobile environment
Authors: Gong Yong-Wang  , Song Yu-Rong  , Jiang Guo-Ping  ,   College of Computer, Nanjing University of Posts and Telecommunications, Nanjing 210003, China;,   College of Automation, Nanjing University of Posts and Telecommunications, Nanjing 210003, China;,   School of Information Engineering, Yancheng Institute of Technology, Yancheng 224051, China
Published: December 2020

In this paper, considering the random motion of nodes, we propose an epidemic spreading model on network of mobile environment based on the mean-filed theory. Using the theory of differential dynamical system, the behaviors of epidemic spreading are further analyzed. It is shown that if R0 1, the epidemic always dies out and the disease-free equilibrium is globally asymptotically stable; and if R0 1, the epidemic is uniformly persistent and the endemic equilibrium is globally asymptotically stable. Numerical simulations are given to validate the results of theoretical analysis.
Runge-Kutta discontinuous Galerkin finite element method for two-dimensional gas dynamic equations in unified coordinate
Authors: Zhao Guo-Zhong  , Yu Xi-Jun  ,   Faculty of Mathematics, Baotou Teachers College, Baotou 014030, China;,   Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

In this paper we develop the Runge-Kutta discontinuous Galerkin finite element method for two-dimensional compressible gas dynamic equations in unified coordinate. The equations for fluid dynamics and geometry conservation laws are solved simultaneously. All the calculations can be performed on the fixed meshes. The information about the grid velocities is not needed in calculation. Some numerical examples are given to evaluate the efficiency and the reliability of the scheme. The numerical results show that the algorithm works well.
A new chaos mapping hash function structural method and its application
Authors: He Ting-Ting  , Luo Xiao-Shu  , Liao Zhi-Xian  , Wei Zheng-Cong  ,   College of Electronic Engineering, Guangxi Normal University, Guilin 541004, China
Published: December 2020

A one-way hash function algorithm is proposed based on the chaos mapping and multiplicative congruential method. The initial value of the system is generated by the pseudo-random sequence which is obtained through the multiplicative congruential method. the normalized ASCII of the plaintext is used as the initial value of the chaos mapping. After a variable-step chaotic digital quantification, 128 bit hash value is extracted from the systems. Theoretical analysis and simulation results show that the proposed method has better characteristics of irreversibility, collision resistance, anti-forgery, initial sensitivity and higher operation speed.
First-principles study of interface relaxation effects on interface structure, band structure and optical property of InAs/GaSb superlattices
Authors: Sun Wei-Feng  , Zheng Xiao-Xia  ,   Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Heilongjiang Provincial Key Laboratory of Dielectric Engineering, School of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China;,   Department of Computer Science and Technology, Heilongjiang Institute of Technology, Harbin 150050, China
Published: December 2020

The first-principles all electron relativistic calculations within the general gradient approximation are performed to investigate the interface structure, the electronic and the optical absorption properties of quaternary InAs/GaSb superlattices with InSb or GaAs type of interface. Because of the complexity and low symmetry of the quaternary interfaces, the equilibrium structural parameters of relaxed interfaces are determined by the minimization of total electronic energy and strain in InAs/GaSb superlattices. The band structures and the optical absorption spectra of InAs/GaSb superlattices with special InSb or GaAs and normal (two types are alternate) interfaces are calculated, with the consideration of the superlattice interface atomic relaxation effects. The calculation of relativistic Hartree-Fock functional and local density approximation with the plane wave method is also implemented to demonstrate the calculated band structure results. The calculated band structures of InAs/GaSb superlattices with different types of interfaces are systematically compared. We find that the chemical bonding and ionicity of interfacial Sb atoms are essentially important in determining the interface structures, the band structures and the optical properties of InAs/GaSb superlattices.
Influence of external forcing on the predictability of Lorenz model
Authors: Li Ai-Bing  , Zhang Li-Feng  , Xiang Jie  ,   Institute of Meteorology, People's Liberation Army University of Science and Technology, Nanjing 211101, China
Published: December 2020

The influence of external forcing on chaotic character, Lorenz map structure and the predictability is studied with the Lorenz system which has a forcing term, and the atmospheric predictability forced by sea surface temperature (SST) is also analyzed. The chaotic attractors are related to the forcing term that changes the moving rules of system and makes randomicity of attractors reduce. The probability distribution function of Lorenz system in the x-y plane has a bimodal structure with two clearly separated peaks. In the absence of forcing, both peaks are equally likely. When an external forcing introduced, the probability of state moving around two Lorenz attractors is changed, and it makes the two peaks asymmetric. It is found that the single cusp of Lorenz map obtained in the absence of forcing splits into two cusps that represent two branches of the Lorenz attractor when the forcing is introduced. On Lorenz map, the moving directions of two cusps and the difference between two cusps and single cusp are determined by the sign and the magnitude of forcing term. The predictability of Lorenz system is also deeply affected by external forcing. The predictability is increased by introducing forcing, and especially the range of increasing is larger when the absolute value of forcing term is bigger. It is also found that the higher potential predictability is obtained by forcing with the stronger SST which causes the larger external variance.
Analysis of symmetrical, periodic negative-permeability metamaterial using interdigital capacitance loading
Authors: Xu Xin-He  , Xiao Shao-Qiu  , Gan Yue-Hong  , Fu Chong-Fang  , Wang Bing-Zhong  ,   Institute of Applied Physics, University of Electronic Science and Technology of China, Chengdu 610054, China;,   Nanchang Hangkong University, Nanchang 330063, China
Published: December 2020

The relations between the scattering matrix and relative Bloch permeability of periodic symmetric magnetic resonance metamaterial are investigated in detail by means of network theory and Floquet's theorem, and we retrieve the Bloch constitutive parameters for four split ring resonators using the relations. Full wave simulations in conjunction with numerical retrieval algorithms show that when we load the interdigital capacitance at the gap of split ring resonator, the magnetic resonance frequency drastically lowers. Our work provides not only theoretical foundation for the Bloch permeability parameter retrieval from periodic metamaterials, but also a novel design way of miniaturizing magnetic resonance metamaterial configurations.
Study of orbital angular momentum entangled photons entanglement in atmospheric channel
Authors: Li Tie  , Chen Juan  , Ke Xi-Zheng  ,   The Faculty of Automation & Information Engineering, Xi’an University of Technology, Xi’an 710048, China
Published: December 2020

In this paper, we describe orbital angular momentum entangled photon pair entanglement in atmospheric channel. The Von Karman spectrum of turbulence is used to create a model of two-photon pair entanglement. The effects of atmospheric turbulence on the entanglement of entangled photon pairs of different orbital angular momentum bases are analyzed. The obtained results are as follows because of the presence of atmospheric turbulence, the entanglement of entangled photon pairs decreases with the increase of the propagation distance z in the atmosphere channel. The entanglement of the entangled photon pairs decreases with the increase of transmission distance. The bigger the turbulence intensity, the faster the entanglement decline and the shorter the propagation distanceis. In the same intensity of atmospheric turbulence of the atmospheric channel, the bigger the orbital angular momentum index, the slower the entanglement decline and the further the propagation distanceis.
Analysis of thermal protection mechanism of leading structure embedded high directional thermal conductivity layer
Authors: Sun Jian  , Liu Wei-Qiang  ,   Science and Technology on Scramjet Laboratory, National University of Defense Technology, Changsha 410073, China
Published: December 2020

The structure of embedded high thermal conductivity layer leading thermal protection is considered as thermal protection system to prevent hypersonic vehicle from the serious aerodynamic heating. By numerical method, we analyze the cooling effect of the leading thermal protection system under given conditions. The maximum outer surface temperature and the inner surface temperature are reduced by 9.1% and by 31.5% respectively. Both high temperature region and low temperature region are blocked in the external layer and the inner temperature distributions are more uniform. The transfer of heat from high temperature region to low one is achieved, the thermal load of the high temperature area is weakened, and the ability of leading thermal protection system is strengthened. The research shows that the cooling effect of leading system increases with the increases of aerodynamic flux ratio and the area ratio of radiative surfaces. The influences of structure parameters and materials properties on thermal protection are discussed, which provides some references for the design of the structure and the selection of materials.
Effects of size and electric field coupling on the surface plasmon properties of gold nanoring dimer structures
Authors: Sun Zhong-Hua  , Wang Hong-Yan  , Wang Hui  , Zhang Zhi-Dong  , Zhang Zhong-Yue  ,   School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China;,   School of Physical Science and Technology, Southwest University, Chongqing 400715, China
Published: December 2020

The extinction spectra and the electric field distribution of the surface plasmon coupling of gold nanoring dimer in horizontal and vertical arrangements are calculated by the discrete dipole approximation method. It is found that the peaks of extinction spectra and electric field distribution of the surface plasmon coupling are sensitive to the size and the separation gap between gold nanorings. It is demonstrated that the peaks of extinction spectra will be red-shifted or blue-shifted due to the different structure parameters of gold nanorings. Because of the effect of the polarization charge coupling between adjacent gold nanoring, the local electric field distribution is found to be stronger for the gold nanoring dimer and trimer in horizontal arrangement than for the single gold nanoring. The horizontal gold nanoring trimer has stronger enhancement of local electric field than the dimer. It shows that the greater separation gap has the weaker local electric field distribution for the gold nanoring dimer and trimer in horizontal arrangement. Therefore the gold nanoring horizontal array is predicted to be an ideal surface enhanced Raman scattering substrate and is expected to have potential applications in biological and chemical detections.
Effective g-factor in high-mobility InGaAs/InP Quantum well
Authors: Wei Lai-Ming  , Zhou Yuan-Ming  , Yu Guo-Lin  , Gao Kuang-Hong  , Liu Xin-Zhi  , Lin Tie  , Guo Shao-Ling  , Dai Ning  , Chu Jun-Hao  , Austing David Guy  ,   National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083, China;,   School of Electrical and Electronic Engineering, Hubei University of Technology, Wuhan 430068, China;,   Key Laboratory of Polar Materials and Devices of Ministry of Education, School of Science and Technology of Information, East China Normal University, Shanghai 200062, China;,   Institute of Microstructural Science M50, National Research Council of Canada, Montreal Road, Ottawa, Ontario K1A 0R6, Canada
Published: December 2020

High-mobility In0.53Ga0.47As/InP quantum well is fabricated by the chemical beam epitaxy technique. Clear Shubnikov-de Hass (SdH) oscillation and beating pattern due to zero-field spin splitting are observed by magnetotransport measurements at low temperature. We use an analytical method, involving the simultaneous fitting of fast Fourier transform spectra of SdH oscillations at different tilted fields, to extract the effective g-factor.
Room temperature absorption spectra analysis of Er3+/Yb3+-doped Hydrothermal Epitaxial Layer on LiNbO3 and LiTaO3 Single Crystal Substrates
Authors: Sun Yu  , Yang Chun-Hui  , Jiang Zhao-Hua  , Meng Xiang-Bin  ,   School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

In this paper we introduce the undetermined parameter kNL which is related to the concentration and thickness, and perform the fitting calculation that is on the basis of the absorption spectrum about the hydrothermal epitaxial polycrystalline sample on the surfaces of LiNbO3 and LiTaO3 doped with Er3+/Yb3+ single crystalline substrates according to the J-O theory at the room temperature. It is obtained that for LiNbO32=2.34 10-20 cm2,4=0.77 10-20 cm2,6=0.31 10-20 cm2, and kNL=4.32 10-2 molm-2. LiTaO32=1.68 10-20 cm2,4=0.84 10-20 cm2,6=0.45 10-20 cm2, kNL=9.17 10-3 mol m-2. This method can be extended to the systems in which the data of concentration and thickness such as powder or colloid are difficult to obtain. According to the up-conversion luminescence analysis and the calculation via spectrum parameters, it is confirmed that both the samples have the green up-conversion luminescence at Er3+:Yb3+=1:1, the method of reducing the energy of matrix phonon is tried to improve the quantum cutting yield of 4I13/2 to 2H11/2 and 4S3/2.
Stochastic resonance in FHN neural system driven by non-Gaussian noise
Authors: Zhang Jing-Jing  , Jin Yan-Fei  ,   Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of Education, Beijing 100081, China;,   Department of Mechanics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

Stochastic resonance (SR) is studied in the FitzHugh-Nagumo (FHN) neural system subject to multiplicative non-Gaussian noise, additive Gaussian white noise and a periodic signal. Using the path integral approach and the two-state theory, the expression of the signal-to-noise ratio (SNR) is derived. The simulation results show that conventional SR and double SR occur in the FHN neural model under different values of system parameters. The effects of the additive and multiplicative noise intensities on SNR are different. Moreover, the addition of non-Gaussian noise is conductive to the enhancement of the response to the output signal of the FHN neural system.
Simulation of pedestrian evacuation with asymmetrical pedestrian layout
Authors: Yue Hao  , Zhang Xu  , Chen Gang  , Shao Chun-Fu  ,   MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology, Beijing Jiaotong University, Beijing 100044, China;,   Automobile Transport Command Department, Military Transportation University, Tianjin 300161, China
Published: December 2020

Simulation of pedestrian evacuation from a room with multi-exit and asymmetrical pedestrian layout is presented based on an improved dynamic parameter model in this paper. The computation and the count-area of imaginary distance are improved based on the Max-Min evacuation path selection of actual and imaginary distance in order to reduce evacuation imbalance caused by the asymmetry of pedestrian layout. An imbalance coefficient is introduced to describe the asymmetry of pedestrian layout. The effects of pedestrian layout asymmetry on the evacuation time are analyzed respectively from fixed and unfixed pedestrian initialization site. The simulation results of the improved and original models are compared and analyzed, and the improved model can effectively reduce evacuation imbalance. Simulation results show that under normal evacuation condition with considerring reasonable pedestrian and jam around exits, evacuation time is hardly affected by pedestrian and exit layout and depends mainly on cognition coefficient, total width of exits and pedestrian initialization amount.
Simulation study on thermodynamic, dynamic and structural transition mechanisms during the formation of Ca70Mg30 metallic glass
Authors: Xu Chun-Long  , Hou Zhao-Yang  , Liu Rang-Su  ,   Department of Applied Physics, Chang'an University, Xi'an 710064, China;,   School of Physics and Microelectronics Science, Hunan University, Changsha 410082, China
Published: December 2020

The rapid quenching process of Ca70Mg30 alloy is simulated by using the molecular dynamics method. During the liquid-glass transition process, the thermodynamic, dynamic and structural transition mechanisms are investigated deeply, and the relations between glass transition temperatures determined by different methods are discussed. It is found that both the simulated structural factor of Ca70Mg30 metallic glass and glass transition temperature are consistent with the experimental results, and the icosahedral local configuration plays a critical role in the formation of Ca70Mg30 metallic glass. The dynamic property of supercooled liquid gradually deviates from the Arrhenius law and satisfies the MCT power law due to the cage effect formed by neighbor atoms. It is also found that the structural glass transition temperature is close to the dynamic one, and they are higher than the calorimetric glass transition temperature. The relationship between them and the ideal dynamic glass transition temperature satisfies the Odagaki relation.