bluuebunny/crossref_metadata_2025 huggingface dataset:
Constrained bifurcations of the system with double-loop bilinear hysteresis
Authors: Wu Zhi-Qiang  , Zhang Zhen-Hua  , Hao Ying  ,   School of Mechanical Engineering, Tianjin University, Tianjin 300072, China;,   Department of Mechanical and Electrical Engineering, Nanyang Institute of Technology, Nanyang 473004, China
Published: December 2020

Systems with double-loop hysteresis are used increasingly in engineering, but few studies on their dynamics are reported. In this study, the bifurcation characteristics of the primary resonance of a system with double-loop bilinear hysteresis are investigated on the background of a shape memory alloy damper. First, the frequency-amplitude response equation is obtained by using the averaging methods. Then, the influences of the temperature and the amplitude of excitation on amplitude-frequency responses are analyzed by the constrained bifurcation singularity analysis method of non-smooth systems. The calculation results show that the parameter space composed of the temperature and the amplitude of excitation can be divided into 11 regions, which suggest that there are 11 qualitatively different kinds of amplitude-frequency responses to the variation of two parameters. In order to describe and compare the frequency-amplitude response curves conveniently, an encoding rule is proposed to describe their jump phenomena as the frequency sweeps. The above results can guide directly the design of frequency response mode of the system.
The perturbed optoacoustic solitons in Bragg grating
Authors: Li Hua-Xing  , Lin Ji  ,   Institute of Nonlinear Physics, Zhejiang Normal Univesity, Jinhua 321004, China
Published: December 2020

We investigate the interaction between acoustic and optical signals in Bragg gratings. Using the multiple-scale method, we convert the optoacoustic coupled mode equations into a standard nonlinear Schrdinger equation. Thus, we obtain approximate solutions of the optoacoustic coupled mode equations, such as the single-soliton solutions and multiple-soliton solutions. Furthermore, we discuss the properties of slowing light of optoacoustic solitons and the interaction of two-soliton solutions.
The stability and paramagnetism of Fermi gas in a strong magnetic field
Authors: Men Fu-Dian  , Wang Hai-Tang  , He Xiao-Gang  ,   College of Science, China University of Petroleum (East China), Qingdao 266555, China
Published: December 2020

By using theoretical analysis and numerical simulation, the stability and the paramagnetism of Fermi gas in a strong magnetic field at low temperatures are studied, and the influences of temperature and magnetic field on the stability and susceptibility of the system are analyzed. The results show that the strong magnetic field causes variation of a system stability, and such a change relates to temperature. While the effects of temperature on stability and susceptibility are relevant to the chemical potential (i.e. the particle number density) of free gas. When the chemical potential is even, the magnetic field weakens the stability of the system, and the increasing of temperature leads to the reduction in the susceptibility of the system. When the chemical potential is odd, the magnetic field strengthens the stability of the system, while the increasing of temperature can increase the susceptibility of the system. With temperature increasing, the effect of the magnetic field on the stability is weakened. With magnetic field increasing, the change of the stability of the system becomes oscillatory, and the oscillation center of the susceptibility shifts down.
A novel frequency selective surface loaded with resistance films absobers
Authors: Zhou Hang  , Qu Shao-Bo  , Peng Wei-Dong  , Wang Jia-Fu  , Ma Hua  , Zhang Dong-Wei  , Zhang Jie-Qiu  , Bai Peng  , Xu Zhuo  ,   College of Science, Air Force Engineering University, Xi'an 710051, China;,   Research Center of Synthetic Electronic Information System and Electronic Countermeasure, Air Force Engineering University, Xi'an 710051, China;,   Key Laboratory of Electronic Materials Research of Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

Commonly, by virtue of the frequency selective surface (FSS) radome's shape, out-band signals are reflected to other directions to achieve a stealth radome. However, with the development of the anti-stealth of poly-state radar technology, such reflected signals can be still detected. In view of this problem, a novel frequency selective surface loaded with resistance film absorbers is proposed. Such an FSS not only has a stable performance for various incident angles and for different polarizations, but also possesses absorptive property to electromagnetic waves in out-band. By virtue of this advantage, the out-band signals can be absorbed and the risk of anti-stealth detection can be greatly reduced. In addition, because of the function of the absorber, grating lobes of the FSS are also restrained, which reduces the interference of operating band.
The effect of nitrogen ion bombarding energy on the bonding structure of nitrogenated tetrahedral amorphous carbon film
Authors: Han Liang  , Shao Hong-Xiang  , He Liang  , Chen Xian  , Zhao Yu-Qing  ,   School of Technical Physics, Xidian University, Xi'an 710071, China;,   Luoyang Institute of Science and Technology, LuoYang 471023, China;,   School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

The tetrahedral amorphous carbon (ta-C) films with more than 80% sp3 in fraction are deposited by the filtered cathode vacuum arc technique. Then the energetic nitrogen (N) ions are used to bombard the ta-C films to fabricate nitrogenated tetrahedral amorphous carbon (ta-C:N) films. The composition and the structure of the films are analyzed by visible Raman spectrum and X-ray photoelectron spectroscopy. The result shows that the bombardment of energetic nitrogen ions can form CN bonds, convert CC bonds into C＝C bonds, and increase the size of sp2 cluster. The CN bonds are composed of C＝N bonds and CN bonds. The content of C＝N bonds increases with the N ion bombardment energy increasing, but the content of CN bonds is inversely proportional to the increase of nitrogen ion energy. In addition, CN bonds do not exist in the films.
Development of high-magnetic-field, high-frequency electronic spin resonance system
Authors: Wang Shao-Liang  , Li Liang  , Ouyang Zhong-Wen  , Xia Zheng-Cai  , Xia Nian-Ming  , Peng Tao  , Zhang Kai-Bo  ,   Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

High-magnetic-field, high-frequency electronic spin resonance (ESR) facility has been first developed in Wuhan National High Magnetic Field Center, China. The facility can achieve a frequency range of 210370 GHz, a temperature range of 2300 K and magnetic fields up to 50 T. The ESR facility has been tested with a sample of ruby. Clear ESR spectra of Cr3+ ion are obtained.
Simulation of dendritic growth for ternary alloys based on modified cellular automaton model
Authors: Shi Yu-Feng  , Xu Qing-Yan  , Liu Bai-Cheng  ,   Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

Based on the binary cellular automaton method, a modified cellular automaton model for ternary alloys is developed to simulate dendrite growth controlled by solutal effects and microsegregation in the low Peclet number regime by coupling PanEngine, which is a multicomponent thermodynamic and equilibrium calculation engine. The model can be used to calculate the interfacial equilibrium composition by considering the influence of Gibbs-Thomson effect induced curvature undercooling, and multicomponents contributed constitutional undercooling. Meanwhile, the growth velocity of interface is determined by solving the solute conservation equation simultaneously with dimensionless solute supersaturation equation for each alloying element. Moreover, equilibrium liquidus temperature and equilibrium solid concentration at the interface are derived by PanEngine. Free dendrite growth of Al-7%Si-xMg ternary alloys is simulated by the present model, which shows that the increase of solute Mg can suppress the growths of both primary and secondary dendrite arms. Meanwhile, constrained columnar dendrite growth of Al-7%Si-0.5%Mg with the increases of pulling velocity and constant thermal gradient during directional solidification is calculated. The results reveal the competitive growth of columnar dendrites, and demonstrate that the primary dendrite arm spacing would decrease as the pulling velocity increases, which accords well with the Hunt model.
An absorbing boundary condition for general dispersive medium and general FDTD spatial scheme
Authors: Zhuansun Xu  , Ma Xi-Kui  ,   State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Published: December 2020

Based on the stretched coordinate perfectly matched layer (SC-PML) formulation and the auxiliary differential equation method, an absorbing boundary condition for general dispersive medium is presented, and applied to both the standard finite difference time domain (FDTD) method and the high-order FDTD method. The proposed D-H formulations are completely independent of the material properties of the FDTD computational domain. Thus they can be directly applied to the simulations involving arbitrary dielectrics. Numerical results show that compared with the CPML, the proposed method is versatile, has an improved absorbing performance and low computational complexity, and can substantially reduce the computational time.
Evolutionary modeling for dryness and wetness prediction
Authors: He Wen-Ping  , Wang Liu  , Wan Shi-Quan  , Liao Le-Jian  , He Tao  ,   National Climate Center, China Meteorological Administration, Beijing 100081, China;,   School of Computer Science and Technology, Beijing Institute of Technology, Beijing 100081, China;,   Yangzhou Meteorological Office, Yangzhou 225009, China;,   Jinan Environment Protection Monitoring Center, Jinan 250014, China
Published: December 2020

A new method of predicting dryness and wetness based on evolutionary modeling (EM) is presented in this paper. Numerical tests indicate that the basic dynamic characteriscs can be captured by EM and the model obtained by EM is not only able to preferablely simulate historical evolution, but also can exactly predict the future evolutionary trend of a time series. For the model obtained by EM with relatively larger prediction errors, the secondary EM can improve the prediction accuracy obviously.
Chaos synchronization of regular network based on sliding mode control
Authors: Li Yu-San  , Wei Lin-Ling  , Yu Miao  , Zhang Meng  ,   College of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China
Published: December 2020

Sliding mode control method is used to study the synchronization of regular network. The method is extended from the single chaos control or synchronization between two chaotic systems to the synchronization of complex network. The sliding surface of the network and the control input are designed. Furthermore, the effectiveness of the method is analyzed based on the stability theory. The Duffing system and the Coullet system are taken as network nodes of the regular network, and the simulation is made to verify the method.
Design and fabrication of 1000 line/mm soft X-ray freestanding blazed transmission gratings
Authors: Chen Yong  , Qiu Ke-Qiang  , Xu Xiang-Dong  , Liu Zheng-Kun  , Liu Ying  , Fu Shao-Jun  ,   National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
Published: December 2020

The performance prediction of freestanding blazed transmission grating is discussed using scalar diffraction theory, and grating design parameters are accodingly given. A freestanding transmission grating with a period of 1 m, duty cycle of 0.10.2, aspect ratio of about 100, thickness of 10 m and fractional area of 65% is successfully fabricated by holographic lithography and anisotropic wet etching. The size of a single die is 15 mm 15 mm divided into four 5 mm 5 mm windows. The diffraction efficiency of the fabricated grating is tested at the National Synchrotron Radiation Laboratory in a wavelength region of 550 nm. The wavelength scanning results show a strong blazing effect in the direction of specular reflection from mirror-like grating sidewalls, as expected. The measured and normalized diffraction efficiency is consistent with the theoretical prediction within 38%49% due to grating structural imperfections. These experimental results prove not only the concept of blazed transmission grating but also practicability of the fabrication process.
Investigation on regulating the topological electronic structure of the half-Heusler compound LaPtBi
Authors: Zhang Xiao-Ming  , Liu Guo-Dong  , Du Yin  , Liu En-Ke  , Wang Wen-Hong  , Wu Guang-Heng  , Liu Zhong-Yuan  ,   School of Material Sciences and Engineering, Hebei University Technology, Tianjin 300130, China;,   State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;,   State Key Laboratory of Metastable Material Sciences, Yansan University Technology, Qinhuangdao 066004, China
Published: December 2020

Using the full-potential linearized augmented plane-wave method based on the density functional theory, we investigate the influences of chemical substitution and uniaxial strain on the topological electronic structure of the half-Heusler compound LaPtBi. It is shown that the 8 band which is protected by the cubic symmetry of the C1b structure can open and form a gap by substituting Sc element for La or Pd for Pt in LaPtBi compound. However, in the case of distorting cubic lattice by using a uniaxial strain, not only the gap mentioned above appears, but also the Fermi level can be tuned regularly. Thus the LaPtBi compound becomes a real topological insulator.
Dynamic behavior of a cavitation bubble in acoustic field and electric field
Authors: Shen Zhuang-Zhi  , Wu Sheng-Ju  ,   Institute of applied Acoustics, Shaanxi Normal University, Shaanxi Institute of Physics,, Key Laboratory of Ultrasonics of Shaanxi Province, Xi’an 710062, China
Published: December 2020

The dynamics of a cavitation bubble under acoustic field and an electric field is studied by regarding liquid as a working medium. The effects of the dimensionless frequency and strength of acoustic field and electric field on cavitation bubble dynamical behaviors by Rayleigh-Plesset equation are numerically investigated. The results show that when acoustic field and electric field are combined, chaos area range of cavitation bubble motion is larger than that when only acoustic field or single electric field exists. This is of significance not only for further research of acoustic cavitation but also for enhancing and improving the cavitation degration of organic pollutant technology.
The Alloying of Ti, C, N in Bulk -Fe and Their Effects on Bond Characters
Authors: Xue Jin-Xiang  , Zhang Ri-Guang  , Liu Yan-Ping  , Wang Bao-Jun  ,   College of Mechanical Engineering, Taiyuan University of Technology, Taiyuan 030024, China;,   Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, China
Published: December 2020

The electronic structures and the bond characters of bulk -Fe with Ti, C, N additions are studied using the first-principls pseudopotential plane-wave method. The total energy and the cohesive energy are calculated, and the Mulliken population, the overlap population, the density of states and the charge density are also analyzed, which can give a microscopic reason why the mechanical property is improved after the infiltration of Ti, C, N into bulk Fe. The calculated results show that with the alloying element Ti(012.5 at%), C(011.11 at%), N(011.11 at%) contents increasing, the cohesive energy of alloy increases slowly and the structure keeps stable. The additions of Ti, C, N into the alloy enhance the reciprocal hybridization in Fermi energy level, and the binding abilities of Ti, C, N, Fe become stronger. The pseudo-gap near the Fermi energy level means the coexistence of covalent and metallic bonds in alloy. With the contents of alloying elements increasing, the covalent bondings between C, N and Ti, Fe become stronger, and part of C and N atoms will be bound to Ti atoms and form TiC and TiN particles, thereby strengthening the dispersion.
The influence of the disorderded substrate potential on static friction force
Authors: Yang Yang  , Wang Cang-Long  , Duan Wen-Shan  , Shi Yu-Ren  , Chen Jian-Min  ,   College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU & IMP CAS, Northwest Normal University, Lanzhou 730070, China;,   Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, Lanzhou 730070, China;,   State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
Published: December 2020

In order to better simulate a real model which can be realized in experiment, we study a two-dimensional(2D) Frenkel-Kontorova(FK) model driven by the disordered substrate potential which is charactered by the sum of identical Gaussian functions. Commensurate and incommensurate interfaces are discussed. In the paper, we mainly analyse the mechanism of friction, and the effects of static friction force on the disordered substrate potential.
Application of FuzzyEn algorithm to the analysis of complexity of chaotic sequence
Authors: Sun Ke-Hui  , He Shao-Bo  , Yin Lin-Zi  , Duo Li-Kun  ,   School of Physics Science and Technology, Central South University, Changsha 410083, China;,   School of Physics Science and Technology, Xinjiang University, Urumqi 830046, China
Published: December 2020

To analyze the complexity of chaotic sequence correctly, complexity of systems, including typical discrete chaotic systems and continuous chaotic systems, are investigated based on the FuzzyEn algorithm. Compared with ApEn, SampEn and Intensive statistical complexity algorithm, the FuzzyEn algorithm is an effective measure algorithm for analyzing chaotic sequence complexity, and it has low sensitivity to and slight dependences on phase space dimension (m), similar tolerance (r) and sequence length (N), better robustness and measure value continuities. Results of the complexities of chaotic systems show that the complexity of continuous chaotic systems are much smaller than those of the discrete chaotic systems. However, having been disturbed by high complex discrete chaotic pseudo-random sequences or classical m-series, the pseudo-random sequences of continuous chaotic systems increase their complexities significantly. Our result provides a theoretical basis for the application of chaotic sequences to the field of cryptography and secure communication.
Investigations of vibrational levels and dissociation energies of diatomic systems using a variational algebraic method
Authors: Zhang Yi  , Sun Wei-Guo  , Fu Jia  , Fan Qun-Chao  , Feng Hao  , Li Hui-Dong  ,   School of Physics, Sichuan University, Chengdu 610065, China;,   School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu 610039, China;,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

The algebraic method (AM) suggested by Sun et. al. is developed into a nodal variational AM (VAM) to offset the possible experimental errors by using an energy variational part δE after analyzing the error amplification effect. The VAM is used to study the full vibrational levels {Eυ} and the dissociation energies De for 51Πu7Li2, (6d)1Δg Na2, (7d)1ΔgNa2 and 51∑+ NaK alkali metal diatomic molecular electronic systems. The results reproduce all known experimental vibrational energies, predict correct dissociation energies and all unknown high-lying levels that may not be given if one uses original AM or other numerical methods or experimental methods. These theoretical analyses and results not only show that the VAM is feasible and correct for many diatomic systems, but also provide constructive reference for other numerical calculations or simulations.
A theoretical study on double differential cross sections for (e, 2e) process of hydrogen
Authors: Yang Huan  , Zhang Sui-Meng  , Xing Ling-Ling  , Wu Xing-Ju  , Yuan Hao  ,   The Center of Basic Experiment, West Anhui University, Lu'an 237012, China;,   Institute of Atomic and Molecular Physics, School of Materials and Chemical Engineering, West Anhui University, Lu'an 237012, China;,   School of Mechanism and Electrical Engineering, West Anhui University, Lu'an 237012, China
Published: December 2020

The double differential cross sections for electron impact ionization of hydrogen at incident energies of 15.6 eV, 17.6 eV, 25 eV and 40 eV are calculated by use of BBK model and modified BBK model. The results of the present work are compared with the absolute experimental date. The structure of the cross sections is analysed and the contributions of exchange effects to corss sections are discussed.
Discrete soliton interaction in quasi one-dimensional optically induced photonic lattice
Authors: Xiao Fa-Jun  , Zhang Peng  , Liu Sheng  , Zhao Jian-Lin  ,   Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072, China;
Published: December 2020

The coherent and the incoherent interactions of discreet solitons in quasi one-dimensional optically induced photonic lattice are theoretically and numerically analyzed. It is found that in-phase solitons attract each other and out-of-phase solitons repel one other. Due to the anisotropy of the nonlinearity, two initially attractive incoherent solitons will repel each other as their interval waveguide number increasing. Moreover, the pendulum-like intertwist of discrete solitons is observed during the incoherent interaction due to the interplay between soliton transverse motions resulting from the soliton interaction and the Bragg reflection of the lattice structure. These results help us to understand how the anisotropy of the nonlinearity response plays a role in discrete soliton interaction and offers the theoretical support for the experimental investigation.
Study of bone fatigue evaluation with ultrasonic guide waves based on elastic modulus
Authors: Zhang Zheng-Gang  , Ta De-An  ,   Department of Electronic Engineering, Fudan University, Shanghai 200433, China
Published: December 2020

How to diagnose the bone fatigue damage at early stages is one of the hot research subjects in bone evaluation field. In this study, the propagation characteristics of ultrasonic guide wave in a long bone under different elastic moduli are analyzed using theoretical calculation and simulation methods. First, theoretical solutions of guided wave in a long bone are calculated. Then, a finite difference time-domain (FDTD) numerical method of simulating the propagation of guide wave in a long bone is presented. The simulation results are in good agreement with the theoretical values. And, the relationship between elastic modulus and the propagation characteristics, including group velocity, central frequency and attenuation, is discussed. The results show that group velocity and central frequency increase with the increase of elastic modulus. However, attenuation decreases with the increase of elastic modulus. Those results demonstrate that the propagation of guide wave can reflect the variation of elastic modulus of long bone, which provides a theoretical basis for evaluating the early stages of fatigue damage in long bone.
Experimental and theoretical investigations of the effect of “Brazil Nut” segregation in vibrating granular matters
Authors: Peng Ya-Jing  , Zhang Zhuo  , Wang Yong  , Liu Xiao-Song  ,   Department of Physics, Bohai University, Jinzhou 121000, China
Published: December 2020

Size segregation is one of important properties of vibrating granular matters. It is significant to understand and study the segregation mechanisms and parameter range of controlling factors of mixed granular matters for the development of industry, agriculture and pharmaceutical. In this paper, we investigate the influence factors and physical mechanisms of "Brazil Nut" segregation experimentally and theoretically. The influences of vibrating acceleration, sizes and densities of large and small granules on the segregation time are analyzed. The hydro-model is used to evaluate segregation time and explain the experimental results qualitatively. Results show that the vibration acceleration is a main controlling factor for "Brazil Nut" segregation in the case of fixed frequency. There is a critical acceleration. When the acceleration is larger then its critical value the main physical mechanism changes from convection to filling voids, and the effect of acceleration on segregation decreases, while the effect of size of large granule on it increases. Furthermore, "Brazil Nut" segregation still arises when the density ratio is equal to 1. The increase of the size or density of small granular may enhance "Brazil Nut" segregation.
Low speed water-entry of cylindrical projectile
Authors: He Chun-Tao  , Wang Cong  , He Qian-Kun  , Qiu Yang  ,   School of Astronautics, Harbin Institute of Technology, Harbin 150001, China
Published: December 2020

Experimental studies of the water-entry of cylinder bodies are conducted using high-speed camera to capture the splashes over the water surface and the subsurface cavity shapes during water entry and the cavity-running phase. Cavity evolution is discussed on single 140 conical cylinder body such as formation, development, and pinch-off of vertical and oblique entry. The dependence of the pinch-off type on the entry velocity is discussed for various entry speeds. The phenomena of two-body water entry in series and side-by-side are discussed in the end of this paper, and the data show that the spatial distance between the two bodies has a great influence on the development and the stability of the cavity and the dynamics of both bodies themselves.
3D simulation optimization and design of multicusp ion source
Authors: Yang Chao  , Liu Da-Gang  , Chen Ying  , Xia Meng-Zhong  , Wang Xue-Qiong  , Wang Xiao-Min  ,   University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

In this paper, a permanent magnet of multicusp ion source is calculated in theory, using the binary collision model to deal with coulomb collision between electrons. Collision between electrons and hydrogen species is treated with the null-collision model. Therefore, the three-dimensional PIC-MCC simulation algorithm is developed. Two optimization design models of multicusp ion source, ET-60U, are simulated by the software. Also, the spatial distribution characteristics and the relevant issues of the volume negative hydrogen ion production rate of the two kinds of ion sources are explored. Finally, The basic idea about the design of the negative hydrogen ion source is proposed. indicating that appropriately regulating the magnetic field distribution of the multicusp ion source can produce uniform ion beam, and that appropriately adjusting the size of the extraction magnetic field and the ion source structure can obtain both the ion beam spatial uniformity and the high production rate.
Influence of Y addition on the glass forming ability and soft magnetic properties of Fe-Si-B amorphous alloy
Authors: Zhang Ya-Nan  , Wang You-Jun  , Kong Ling-Ti  , Li Jin-Fu  ,   State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200240, China
Published: December 2020

Addition of rare earth elements can significantly improve the glass forming ability of Fe-based alloys. But the magnetic domain that most of the rare earths possess themselves always worsens soft magnetic properties of the alloys. By contrast, the rare earth element Y does not have this kind of magnetic domain itself, and is an ideal candidate to add to the Fe-based amorphous alloys as soft magnetic materials. In order to systematically study the effect of partial substitution of Fe in Fe78Si9B13 alloy with rare earth element Y on glass forming ability and soft magnetic properties, a series of wedge-shaped specimens and amorphous ribbons are prepared by copper mold suction casting and melt spinning respectively. It is found that the replacement of Fe by minor Y enhances the glass forming ability of the alloy. When 3 at.% Fe is replaced, the critical thickness and supercooled liquid region of the amorphous alloy reach their maximum values, 313 μm and 65 K, respectively. The amorphous alloys have excellent soft magnetic properties: coercive force (Hc) all bellow 200 A/m and saturation magnetic induction (Bs) all above 1.30 T. Specially, Bs reaches a maximal value, 1.67 T, when 1 at.% Fe is substituted.
A new grid multi-wing chaotic system and its circuit implementation
Authors: Zhou Xin  , Wang Chun-Hua  , Guo Xiao-Rong  ,   College of Information Science and Engineering, Hunan University, Changsha 410082, China
Published: December 2020

In this paper, a new three-dimensional autonomous chaotic system is proposed. However, the structural form of the new chaotic system is limited to a double-wing like most Lorenz-like systems. According to the equilibrium points and topological structure of this double-wing chaotic system we design some appropriate nonlinear functions for it. Then, the new double-wing chaotic system can be modified into a grid multi-wing chaotic system. Basic dynamical properties of the system are studied by theoretical analysis and numerical simulation, which proves the chaotic behaviors of this new grid multi-wing chaotic system. Finally, an oscillator circuit is designed for implementation. The circuit simulation results are in good agreement with the numerical simulation results.
Nanoscale stabilization of metastable phase: thermodynamic model and experimental studies
Authors: Song Xiao-Yan  , Xu Wen-Wu  , Zhang Zhe-Xu  ,   College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100124, China
Published: December 2020

A thermodynamic model, into which the nanoscale effect is introduced, is established to describe the thermal parameters of metastable phase, as well as their changes with the concentration, temperature and grain size. Based on the model calculations and experiments, the thermodynamic properties and dependence on the grain size are disclosed. Taking the metastable SmCo7 phase for example, the conditions for the single-phase stability and the phase decomposition are studied. The results are important for the control of the phase stability and phase transformation of the metastable-phase alloy.
Sum-of-square-based impulsive control for chaotic system based on polynomial model
Authors: Yang Jun  , Sun Qiu-Ye  , Yang Dong-Sheng  ,   College of Information Science and Engineering, Northeastern University, Shenyang 110819, China
Published: December 2020

In this paper, we present a novel impulsive control method based on polynomial model for a large class of chaotic systems. First, the polynomial model is used to model the chaotic system, in which the state equation of the system is composed of the polynomial matrix of the system and the column vector of monomials in state. Compared with others modeling methods, any pre-defined hypothesis is removed. Next, a sum-of-square (SOS)-based impulsive control method is investigated to guarantee that the chaotic system is asymptotically stable. It can obtain larger impulsive interval using SOS-based optimization algorithm over linear matrix inequality technique, which means the same control performance can be realized by less control action. Finally, the simulation is provided to demonstrate the effectiveness of the proposed method.
Chaos analysis of high-frequency harmonics of locomotive LCI
Authors: Zhang Kun  , Zhang Yang  , Zha Xiao-Ming  , Xiong Yi  , Peng Guang-Qiang  , Fan You-Ping  ,   School of Electric Engineering, Wuhan University, Wuhan 430072, China
Published: December 2020

Considering typical AC-DC-AC multiple units, CRH2 motor car, in this paper we deduce its parametric equations under sine pulse width modulation, and set up a new nonlinear parameter model. Fractal situation of higher harmonic is analyzed based on chaos theory. Aiming at typical traction substations, calculation and simulation are conducted, and the result is verified based on data from actual wave records, which proves that high-frequency harmonic can lead to system resonance and expands the application of chaos analysis method.
Scattering of electrons in linearly polarized high-intensity laser standing waves
Authors: Tian Mi  , Zhang Qiu-Ju  , Bai Yi-Ling  , Cui Chun-Hong  ,   College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
Published: December 2020

We investigate the motion of electrons in linear polarization relativistic laser standing wave field. The dependences of scattering electron incident in laser polarization plane on the electron initial position, energy and the laser intensity are analyzed. The results indicate that the interaction between electron scattering and sanding wave has a close relationship with the electron relative energy γ0/a0. The initial energy of electron has a critical value by which the forward and backward scattering can be distinguished from each other. The critical energy needed for electron forward scattering increases by the laser intensity. Measured by electronic relative energy, the critical value is in a about 1.0-1.25 range. For the same initial energy, the extent of electron incident plane leading to the forward scattering reduces when the laser intensity becomes higher. Moreover, electrons with low energy easily tend to pass through the standing wave from node planes. Electron oscillation-center and ponderomotive force reversal effect exist merely when the electron relative energy is in a certain range. The electron initially rest on optical axis. The inelastic scattering in which the energy can be exchanged between the electron and the field is also discussed.
Elastic properties of β-HMX under extra pressure: a first principles study
Authors: Su Rui  , Long Yao  , Jiang Sheng-Li  , He Jie  , Chen Jun  ,   College of Physics Science and Technology, Sichuan University, Chengdu 610064, China;,   Institute of Applied Physics and Computational Mathematics, Beiging 100088, China
Published: December 2020

The elastic properties of the β-HMX under an extra pressure are studied from density functional theory calculations using the projector augmented wave method. The calculated bulk modulus and shear modulus under zero pressure are 12.7 GPa and 4.4 GPa which are in good agreement with the available experimental results. A detailed analysis of the pressure-dependent stiffness tensor shows that the bulk modulus and shear modulus both increase as the pressure increases. As the pressure goes up to 7 GPa, the lattice is unstable along the direction of the shear strain. This result agrees well with the results of Raman scattering experiment.
The optimization of lithography process on the deep muti-stepped surface
Authors: Sun Li-Yuan  , Gao Zhi-Yuan  , Zou De-Shu  , Zhang Lu  , Ma Li  , Tian Liang  , Shen Guang-Di  ,   Key Laboratory of Opto-Electronics Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China
Published: December 2020

In this article, we investigate the problems existing in the lithography on the deep multi-stepped surface. Different photoresist thicknesses above and under the step are measured in experiment. The relationship between step height and photoresist thickness is discussed and numerically described. Based on the description of Beer model about the light absorption coefficient, the curves of different light transmittances at different times are analysed. Reasons why the light transmittance changes with time are explained, and the light absorption coefficient is believed to be related to photoresist thickness. On this basis, the lithography process is optimized. The patterns with narrow line-width under the deep step on the wafer are obtained.
Room-temperature ultrafast spin dynamics in colloidal CdSe quantum dots
Authors: Li Xia  , Feng Dong-Hai  , Pan Xian-Qun  , Jia Tian-Qing  , Shan Lu-Fan  , Deng Li  , Sun Zhen-Rong  ,   State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China;,   State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
Published: December 2020

Time-resolved Faraday rotation spectroscopy is used to study the spin coherence in colloidal CdSe quantum dots at room temperature. Spin dephasing time and relevant dephasing mechanisms are analyzed in different transverse magnetic fields. The exciton spin-dephasing time is 102 ps in a zero magnetic field, which is affected by hyperfine interaction between electron and nuclear spins. In a transverse magnetic field of 250 mT, the exciton spin-dephasing time becomes 294 ps due to the fact that the presence of magnetic field makes the nuclear spin fluctuations unimportant. Further increasing the external magnetic field, the spin dephasing time becomes shorter. The magnetic field dependence of the exciton spin dynamics shows that the spin dynamics is dominated by the inhomogeneous dephasing in high magnetic fields (≥ 250 mT).
The light absorption enhancement in polymer solar cells with periodic nano-structures gratings
Authors: Li Guo-Long  , Li Jin  ,   Ningxia Key Laboratory of PV Materials, Ningxia University, Yinchuan 750021, China
Published: December 2020

The thickness of the active layer is limited by its low carrier mobility in the polymer solar cell composed of the blend bulk-heterojunction formed by P3HT as donor material and PCBM as acceptor material, which can affect the light absorption in the polymer solar cell. Nano-structure gratings inserted into polymer layer can redistribute the electrical field inside the device and improve its light absorption. Two-dimensional electrical field distributions inside the polymer solar cell are simulated with the grating period of 1 μ, fill ratio of 0.5 and incident wavelengths of 500 nm and 700 nm based on finite difference time domain. The light absorptions by the devices with different grating depths and fill ratios are calculated based on rigorous coupled wave. The analysis illustrates that light spots occur in the device due to the light diffraction caused by the gratings and the light absorption is increased by 4.2% with a grating fill ratio of 0.5, depth of 10 nm and an incident light wavelength of 512 nm. In experiment, nano-structure gratings are introduced into the devices by the micro-printing technology with PDMS and polymer solar cell is structured with ITO/ PEDOT:PSS gratings/ P3HT:PCBM/ LiF/ Al. The experimental results from the planar and the grating devices prove that the nano-structure gratings embedded in PEDOT:PSS layer increase the power conversion efficiency by 31%.
The interaction of H2D+ with thin solid foils and the detection of its structure
Authors: Zhu Zhou-Sen  , Yuan Xue-Dong  , Miao Jing-Wei  , Shi Mian-Gong  , Liao Xue-Hua  , Fang Cai-Jin  ,   Institute of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610066, China;,   Institute of Nuclear and Technology, Sichuan University, Chengdu 610064, China
Published: December 2020

The Interaction between molecular ion H2D+ and ultra-thin solid film is reported for the first time. The importance of H2D+ in the areas such as astrophysics is stated and the study on H2D+ of recent years is outlined. The formation mechanism for the H2D+ under laboratory conditions is also analysed. The structural pattern of H2D+ and the mean internuclear separation are determined using Coulomb explosion technique. Once again, the existence of wake effects in the interaction of molecular ions with solid is confirmed and three-body wake effect module is used to determine the geometric structure of H2D+. Finally, the unusual structure of the wake of energy spectrum for the heavier ions in the H2D+ Coulomb explosion is discussed.
On the validity of factorization law for the entanglement evolution of two qubits
Authors: Huo Ya-Jing  , Li Jun-Gang  ,   School of Physics, Beijing Institute of Technology, Beijing 100081, China
Published: December 2020

The validity of factorization law for the entanglement evolution of two qubits coupled to two independent non-Markovian channels is investigated. It is found that for some initial states, such as the Bell state and the maximally entangled mixed state, the entanglement can be characterized by the factorized entanglement when the effects of the channels are weak. For the general initial states, the factorized entanglement provides us with a good approximation to characterize the entanglement dynamics when the entanglement is large.
Perturbation solution of single-phase AC-DC converter based on nonlinear oscillation and chaotic analysis
Authors: Zhang Yang  , Zha Xiao-Ming  , Liu Ya-Qi  , Zhang Kun  , Xiong Yi  , Fan You-Ping  ,   School of Electric Engineering, Wuhan University, Wuhan 430072, China;,   School of Information Management, Wuhan University, Wuhan 430072, China
Published: December 2020

This paper deals with the issue of modeling method by perturbation solution to the single-phase AC-DC converter. A continuous circuit that includes a single-phase AC-DC converter is inducted first. And then a differential equation is presented with two parameters, which are controlling parameter and small perturbation parameter. A strict proof indicates that this equation can be solved by the regular perturbation. The compareison between the result and the simulation figures of PSCAD/EMTDC, shows that the result is correct and simple, thus avoiding the requirements for large computation capacity. Finally, the physical significance of the two parameters is analyzed, showing that they may incur the period-doubling chaos. This method not only fits the single-phase AC-DC converter circuit, but also meets the need of two-phase or N-phase circuits.
Determing the entanglement of quantum nonbinary graph states
Authors: Xu Jian  , Chen Xiao-Yu  , Li Hai-Tao  ,   College of Information and Electronic Engineering, Zhejiang Gongshang University, Hangzhou 310018, China
Published: December 2020

Graph states are multipartite entangled states that correspond to mathematical graphs, where the vertices of the graph now play the role of quantum multilevel systems and edges represent interactions of the systems. Graph states are the basis of quantum error correction and one-way quantum computer. We systematically study the entanglement of non-binary graph states. Using iterative algorithm and entanglement bounds, we calculate the entanglement of all the ternary graph states up to nine vertices and parts of quaternary and quinary graph states modulo local unitary transformations and graph isomorphisms. The entanglement measure can be the geometric measure, the measure of relative entropy of entanglement or the measure of logarithmic robustness. We classify the graph states according to the entanglement values obtained. The closest product states obtained in the calculations are studied.
Evolution of interference patterns of strongly interacting Fermi gases in a harmonic trap
Authors: Wen Wen  , Li Hui-Jun  , Chen Bing-Yan  ,   Department of Mathematics and Physics, Hohai University, Changzhou Campus, Changzhou 213022, China;,   Institute of Nonlinear Physics, Zhejiang Normal University, Jinhua 321004, China
Published: December 2020

We study the evolution of the interference patterns of strongly interacting Fermi gases in a harmonic trap after removal of the optical lattice, by numerically solving the superfluid order-parameter equation. We find that for the strongly interacting Fermi gas elastic collisions during the expansion blur the interference peaks. In order to obtain a nearly ballistic expansion, the fast magnetic field ramp technique is applied in experiment. We simulate the fast magnetic field ramp process before expansions of strongly interacting Fermi gases. We find that clear interference patterns are formed, and oscillate for a long time in the harmonic trap. We also calculate the interference patterns in different superfluid regimes, which accord with the experimental observations.
Multi-scale strategy and data surrogating test: two elements for the detection of time irreversibility in heart rate variability
Authors: Hou Feng-Zhen  , Huang Xiao-Lin  , Zhuang Jian-Jun  , Huo Cheng-Yu  , Ning Xin-Bao  ,   Key Laboratory of Modern Acoustics of Ministry of Education, Institute of Biomedical Electronic Engineering, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China;,   Information Management Teaching and Research Center, Department of Science, China Pharmaceutical University, Nanjing 210009, China
Published: December 2020

Based on the method of multi-scale space (Pm, Gm) and data surrogating test, time-irreversibility analysis is applied to the heart rate variabilities (HRVs) from different crowds and different states, awake and asleep respectively, of healthy youths. The results show that i) the HRVs of healthy crowed have irreversible dynamics prevailingly, while the irreversibility decreases but does not disappear with aging or heart disease appearing. For example, most (more than 75%) of the congestive heart failure (CHF) patients still have irreversible dynamics; ii) for HRVs of healthy crowd, irreversible dynamics presents the daytime/nighttime rhythms and their significant difference between in daytime and in nighttime. And a stronger irreversibility is detected in nighttime. HRV is generated by the cardiac dynamic system, in which regulations usually perform via multiple feedback loops with different delays. Therefore, in order to arrive at a reliable conclusion, multi-scale strategy and data surrogating test are suggested to serve as the two elements for the detection of time irreversibility in HRV. The proposed method combines these two elements and reaches a conclusion consistent with the conclusions in previous reports.
Research of secondary fringes in field-widened achromatic, temperature-compensated wind, imaging interferometer (FATWindII)
Authors: Dai Hai-Shan  , Zhang Chun-Min  , Mu Ting-Kui  ,   MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi’an Jiaotong University, Xi’an 710049, China
Published: December 2020

The accurate method to calculate secondary fringes of field-widened, achromatic, temperature-compensated wind imaging interferometer (FATWindII) is presented, and the distribution of secondary fringes on instrument detector is simulated. The effects of secondary fringes on inversion errors of temperature and wind velocity are calculated. The formulas of modulation functions and phase shifts are derived when the wedge compensating glasses with arbitrary tilt angles, and the optimal tilt angles of wedge compensating glasses are obtained in FATWindII. By adopting antireflection film and wedge compensating glasses, the relative intensity of secondary fringes is reduced to below 2.5%, and the inversion errors of temperature and wind velocity introduced by the effects of secondary fringes can be minimized to about 0.05 K and 0.045 m·s-1 respectively. The research has important theoretical significance and practical guidance for the FATWind instrument design, fabrication and calibration.