bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic entropy change and magnetic-field-induced strain in polycrystalline Ni47Mn32Ga21 alloy
Authors: Cai Pei-Yang  , Feng Shang-Shen  , Chen Wei-Ping  , Xue Shuang-Xi  , Li Zhi-Gang  , Zhou Ying  , Wang Hai-Bo  , Wang Gu-Ping  ,   School of Physics and Electronic Engineering, Taizhou University, Taizhou 318000, China
Published: December 2020

The Ni47Mn32Ga21 polycrystalline alloy is prepared by the directional solidification technique. The components and the microstructure of the alloy are investigated using SEM, metallography and EDS methods. The magnetic entropy change in the process of the structural and magnetic phase transition, and magnetic-field-induced strains with pressure are also studied through analyzing the magnetization as a function of temperature, and the isotherm magnetization and magnetic field-induced strain curves. The results show that there is little difference between the component and the designed component. The alloy is comprised mainly of martensitic phase at room temperature. In the heating process, the magnetic entropy change reaches a maximum value and has a larger peak half width near Curie temperature(365 K). The maximum value of the magnetic entropy change is -1.45 J/kg K in a magnetic field of 747 kA/m and its peak half width is 21 K. The Ni47Mn32Ga21 alloy exhibits excellent free recoverability of the magnetic-field-induced strains at room temperature(298 K). The magnetic-field-induced strain reaches a saturated value of -67010-6 without extra stress in a field of 480 kA/m. When the compressive stressis parallel to the direction of the magnetic field, the magnetic-field-induced strain increases evidently with the increase of the pressure, which reaches -130010-6 under a pressure of 27.3 MPa. Meanwhile the strain does not reach the saturated value.
Irreversible exchange-spring processes of antiferromagnetically exchange coupled hard-soft-hard trilayer structures
Authors: Guo Guang-Hua  , Zhang Guang-Fu  , Wang Xi-Guang  ,   School of Physics Science and Technology, Central South University, Changsha 410083, China
Published: December 2020

The demagnetization processes of antiferromagnetically exchange-coupled hard-soft-hard trilayer structures are studied based on the one-dimensional atomic chain model. It is found that when the magnetic anisotropy of soft layer is taken into account, the change of the soft layer thickness or the interfacial exchange coupling strength may lead to a transition from the reversible exchange-spring process to the irreversible process. For the trilayer structures with very thin soft layer, the demagnetization process exhibits typical reversible magnetic exchange-spring behavior. However as the thickness of soft layer increases, there appears a crossover point tc, after which the process becomes irreversible. There occurs also a critical interfacial exchange constant Ashc, above which the exchange-spring process is reversible. When AshAshc, the irreversible exchange-spring process is realized. The phase diagrams of reversible and irreversible exchange-spring process are mapped in the plane of the interfacial exchange coupling Ash and soft layer thickness Ns. The dependences of the bending field on the soft layer thickness for different interfacial exchange couplings are numerically examined.
Micro-morphology and dielectric properties for (K0.45Na0.55)NbO3 lead-free piezoelectric crystal
Authors: Chen Chao  , Jiang Xiang-Ping  , Wei Wei  , Li Xiao-Hong  , Wei Hong-Bin  , Song Fu-Sheng  ,   Department of Material, Jingdezhen Ceramic Institute, Jingdezhen 333001, China
Published: December 2020

Lead-free piezoelectric 〈001〉-oriented KNN crystals each with a dimension of 5 mm3 mm1 mm are obtained by melt grown technique. The room temperature crystal structure of orthorhombic perovskite-type lattice is determined from XRD measurment. The SEM observation reveals the growth steps aligning approximately along the [001] direction. Base on the model of negative ion coordination polyhedrons, it is explained that the layer growth mechanism is dominant for the 〈001〉 face. Two phase transition temperatures of orthorhombic-to-tetragonal (O-to-T) and tetragonal-to-cubic (T-to-C) are around 240 ℃ and 405 ℃ for KNN crystals according to the dielectric measurements, respectively. A linear fitting of the modified Curie-Weiss law to experimental data shows that the normal ferroelectric property is dominant for KNN crystal.
Numerical study of effect of geometrical parameters on the passband of left-hand material
Authors: Gong Qiao-Xia  , Zhao Shuang-Shuang  , Duan Zhi-Yong  , Ma Feng-Ying  ,   School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China
Published: December 2020

We systematically study the transmission property of metallic short-slab pair and continuous wire structure metamaterial and its dependence on the system geometrical parameters in the infrared frequency regime, using the transfer-matrix method and the commercial code, CST Microwave Studio. It is found that the passband is sensitive to the length and the thickness of the continuous wire. As the length or thickness increases, the passband is slightly extended to a higher frequency. It is also found that the dependence of the passband on the material of dielectric layer.
Formation mechanism of layered microstructure and monotectic cell within rapidly solidified Fe62.1Sn27.9Si10 alloy
Authors: Li Zhi-Qiang  , Wang Wei-Li  , Zhai Wei  , Wei Bing-Bo  ,   Department of Applied Physics, Northwestern Polytechnical University, Xi'an 710072, China
Published: December 2020

Ternary Fe62.1Sn27.9Si10 monotectic alloy is rapidly solidified in drop tube with the freely-falling-body techniqual and with melt spinning method separately. The phase separation, the microstructure characteristics, and the heat transfer of this alloy are investigated theoretically. Under free fall condition, the core-shell structure with two layers is formed because of Marangoni migration and surface segregation, where the Sn-rich phase is always located at droplet surface and the Fe-rich phase in the center. With the decrease of droplet diameter, both cooling rate and temperature gradient increase quickly, which facilitates the rapid growth of monotectic cell. With the increase of wheel speed, the cooling rate of alloy ribbon increases from 1.1107 to 6.5107 K/s, the fluid flow and the phase separation are suppressed to a great extent, and the nine layers two layers no layer structural transition occurs during the rapid solidification of Fe62.1Sn27.9Si10 alloy obtained by the melt spinning method. Meanwhile, the FeSn+L2FeSn2 peritectic transformation is also suppressed, thus resulting in different phase constitutions as compared with the case of free fall condition. The energy dispersive spectroscopy (EDS) analysis reveals that the Fe phase exhibits a conspicuous solute trapping effect during rapid solidification.
Kinetic property analysis of emergent behaviors in Swarm model
Authors: Wu Yu  , Yang Jing-Jing  , Wang Li  ,   Institute of Web Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
Published: December 2020

Emergence is one of the important characteristics of complex systems. At present, there is no definite conclusion on what emergence is and how it happens. Swarm model is selected for theoretical research. For convenience of doing so, its specific definition is given, and then the kinetic properties of this model are analyzed. By viewing the energy property, it is proven that under special circumstances the mean square deviation of each kinetic parameter would fall into a certain value space. Experimental results show that under certain conditions, by setting the initial state and parameters of the control equations, the behavior of Swarm can be effectively constrained.
Fault diagnosis for a class of output-coupling complex dynamical networks with time delay
Authors: Zhao Yan-Yan  , Jiang Guo-Ping  ,   College of Automation, Nanjing University of Posts and Telecommunications, Nanjing 210003, China
Published: December 2020

Fault diagnosis is a challenging issue in complex dynamical networks. In the real-world complex dynamical networks, there exists much uncertain information, such as unknown topological structure and uncertain node parameters. Based on network outer synchronization, an approach to fault diagnosis is proposed for a class of output-coupling time delay complex dynamical networks with unknown node parameters. Output variables are used to construct the controllers. A few conditions satisfying outer synchronization are specified from Lyapunov stability theorem. The proposed approach can be used to monitor the online evolution of time-delay network topological structure. Numerical simulations are given to verify the effectiveness of the proposed approach.
A method of solving a class of disturbed Lorenz system
Authors: Zhou Xian-Chun  , Lin Wan-Tao  , Lin Yi-Hua  , Yao Jing-Sun  , Mo Jia-Qi  ,   College of Electronic and Information Engineering, Jiangsu Technology and Engineering Center for Meteorological Sensor Network,Nanjing University of Information Science and Technolog, Nanjing 210044, China;,   LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;,   Department of Mathematics, Anhui Normal University, Wuhu 241003, China
Published: December 2020

A solving problem for the Lorenz system in atmospheric physics is considered. First, a set of variational iterations is constructed by using the generalized variation principle. Then, the initial approximate solution is determined. Finally, using the variational iteration, each approximate solution for corresponding model is found. The generalized variational iteration method is an analytic method, and the obtained solution can be analytically operated further.
Dynamics of cubic and quintic nonlinear Schrdinger equations
Authors: Hua Wei  , Liu Xue-Shen  ,   Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
Published: December 2020

We solve one-dimensional(1D) cubic and quintic nonlinear Schrdinger equations by the symplectic method. The dynamical property of the nonlinear Schrdinger equation is studied with using diffenent nonlinear coefficients. The results show that the system presents quasiperiodic solution, chaotic solution, and periodic solution with the cubic nonlinear coefficient increasing, and the breather solution reduced into a fundamental soliton solution under the modulation of the quintic nonlinear coefficient.
Wigner function of two-mode squeezed number state and its properties
Authors: Song Jun  , Fan Hong-Yi  , Zhou Jun  ,   Department of Material and Chemical Engineering, West Anhui University, Liu'an 237012, China;,   Department of Material Science and Engineering, Department of Physics, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

By means of the entangled state representation as well as the Wigner operator in such a representation, the Wigner function of the two-mode squeezed number states is derived. The properties of corresponding Wigner function in the phase space are discussed by numerical calculation. The results indicate that Wigner function distribution in the phase space should be influenced by the correlation and the entanglement between two modes of two-mode squeezed number state.
Global control of chaotic systems based on linear state feedback
Authors: Sun Chang-Chun  , Fang Bo  , Huang Wen-Hu  ,   School of Astronautics, Harbin Institute of Technology, Harbin 150001, China;,   School of Science, Shenyang Jianzhu University, Shenyang 110168, China
Published: December 2020

By analyzing structural characteristics of nonlinear vector field for a class of chaotic systems, a new approach to controlling chaos globally and rapidly is put forward. Based on linear state feedback, an independent stable equation of some state variables is separated. Controlled chaotic systems degenerate gradually into stable linear systems. Nonlinear quivering phenomenon is eliminated completely further. The approach can be used to control Lorenz system families or new chaotic systems with similar structures. A class of simple controllers is designed to guarantee that closed-loop systems are globally asymptotically stable at the origin. Numerical examples illustrate the shortcut and the validity of the presented approach in this paper.
Adaptive anti-synchronization of unified hyperchaotic system with fully unknown parameters
Authors: Abdurahman Kadir  , Wang Xing-Yuan  , Zhao Yu-Zhang  ,   Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, DALIAN 116024, China;,   School of Computer Science and Engineering, Xinjiang University of Finance and Economics, Urumchi 830012, China
Published: December 2020

In this paper, We investigate the adaptive anti-synchronization in a unified hyperchaotic system with unknown parameters. First, according to the Lyapunov stability theory, We achieve an adaptive controller and show that the controller can make a unified hyperchaotic system with unknown parameters asymptotically stable at a fixed point. Second, by the adaptive anti-synchronization method, We design an adaptive anti-synchronous controller and thereby achieve the hyperchaotic system synchronization. Finally, numerical simulations show the effectiveness of the scheme.
The bound for a class of four-dimensional hyperchaotic system and its synchronization
Authors: Zhang Xiao-Dan  , Cui Li-Juan  ,   School of Mathematics and Physics,University of Science and Technology Beijing,Beijing 100083,China
Published: December 2020

In this paper, a class of four-dimensional continuous autonomous system is studied. It has only one balance under certain conditions but it shows a complicated dynamic behavior. The equilibrium points and lyapunov exponents of the system are analyzed. The bound of this system is estimated and the expression of the bound is presented. In addition, the complete synchronization is also discussed by designing a linear controller. Finally, the corresponding numerical simulations are performed.
A new network structure entropy based node difference and edge difference
Authors: Cai Meng  , Du Hai-Feng  , Ren Yi-Ke  , Marcus W  ,   School of Management, Xi'an Jiaotong University, Xi'an 710049,China;,   Center for Administration and Complexity Science, Xi'an Jiaotong University, Xi'an 710049, China;,   School of Management, Shanxi Normal University, Linfen 041004, China;,   Morrison Institute for Population and Resource Studies,Stanford University,Stanford 94305,USA
Published: December 2020

Entropy is a very important indicator which describes the heterogeneity of the networks. Two kinds of structure entropies, which are based on degree distribution and relative degree respectively, have some problems to describe the characteristics of network structure. Because they focus only on one of node or edge factors. In this paper, We consider the difference between node and edge to define a new network structure entropy. The theoretical analyses and the simulation experiments on regular network, random network and scale-free network prove that this new network structure entropy is more effective to reflect the characteristics of network structure, especially more reasonable to describe the sparse network and star network.
Phase transitions and the mean first passage time of an asymmetric bistable system with non-Gaussian Lvy noise
Authors: Gu Ren-Cai  , Xu Yong  , Zhang Hui-Qing  , Sun Zhong-Kui  ,   Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an 710129, China
Published: December 2020

This paper aims to investigate an asymmetric bistable system driven by non-Gaussian Lvy noise. The stationary probability density functions are obtained by the Grnwald-Letnikov scheme, and the effects of noise intensity and stability index on the stationary probability density are examined. Phase transitions can be observed though a qualitative change of the stationary probability distribution, which indicates that the phase transitions are induced by the asymmetric parameter and the stability index of Lvy noise. Additionally, the mean first passage time is considered, and different mechanisms for the effects of asymmetric parameter, noise intensity and stability index on first passage time are also obtained.
Synchronizing fractional chaotic systems with different orders
Authors: Hu Jian-Bing  , Xiao Jian  , Zhao Ling-Dong  ,   School of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China;,   School of Electronics & Information, Nantong University, Nantong 226019, China
Published: December 2020

To synchronize fractional chaotic systems with different orders, a method is proposed in which a fractional chaotic system with different orders is changed into a fractional chaotic system with the same order but different structures, according to the properties of fractional differential equation. This method is successfully used to synchronize fractional Lorenz chaotic systems. Numerical simulation demonstrates the effectiveness of the method.
Mei symmetry and Mei conserved quantity of Appell equations for nonholonomic systems of Chetaevs type with variable mass
Authors: Yang Xin-Fang  , Sun Xian-Ting  , Wang Xiao-Xiao  , Zhang Mei-Ling  , Jia Li-Qun  ,   School of Science, Jiangnan University, Wuxi 214122, China;,   Electric and Information Engineering College, Pingdingshan University, Pingdingshan 467002, China
Published: December 2020

Mei symmetry and Mei conserved quantity of Appell equation for a nonholonomic system of Chetaevs type with variable mass are studied. The Appell equation and differential equation of motion of the system are set up. The expression of the total derivative of the function along the trajectory of the system with respect to t, the definition and criterion of Mei symmetry of Appell equation for a nonholonomic system of Chetaevs type with variable mass under the infinitesimal transformation of group are given. The structural equation of Mei symmetry and the expression of Mei conserved quantity expressed by Appell equation are obtained. An example is given to illustrate the application of the results.
Another kind of conserved quantity induced by Mei symmetry of mechanico-electrical system
Authors: Liu Xiao-Wei  , Li Yuan-Cheng  ,   College of Physics Science and Technology, China University of Petroleum (East China) Qingdao 266555,China
Published: December 2020

Another kind of conserved quantity deduced from Mei symmetry of mechanico-electrical system is studied. Under the infinitesimal transformation of groups, another kind of conserved quantity of Mei symmetry of mechanico-electrical system is obtained from the definition and the criterion of Mei symmetry of mechanico-electrical system. Finally, an example is given to illustrate the application of the result.
Ground state properties of Rn isotopes within the relativistic mean field theory
Authors: Chen Xing-Peng  , Wang Nan  ,   College of Physics, Shenzhen University, Shenzhen 518060, China
Published: December 2020

The ground state properties of Rn isotopes are studied within the framework of relativistic mean field theory. The pairing correlation is treated by the BCS method. The calculation results are in good agreement with the experimental data. The quadrupole deformations can be founded mainly in the regions with neutron number far from magic number (N=110-124) and (N=129-142). In the regions where the neutron number is larger than the magic number(N=127-142), the hexadecapole deformations are also significant. The isotope shift for Rn isotope is also studied and a drastic change in the slope of the curve is found near the magic neutron nuclei.
Synchrotron K-edge subtraction imaging and its application to metallic foams
Authors: Zhang Qiang  , Hiroyuki Toda  ,   School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;,   Department of Mechanical Engineering, Toyohashi University of Technology, Aichi 441-8550, Japan
Published: December 2020

On the basis of sudden change of linear absorption coefficient (LACs) in the vicinity of absorption edge, the synchrotron K-edge subtraction technique is developed to label the three-dimensional (3D) distribution of element. In this work, tomographic scans above and below the specific absorption edge of Zn are carried out and the subtracted image is used to identify and quantify the 3D distribution of Zn element inside the cell wall of Al-Zn-Mg foam. A non-uniform spatial distribution of Zn element is found in the cell wall of as-cast foam. After long solution tratment, the concentration of Zn element tended to be homogeneous. It is confirmed that the local agglomerated Zn-bearing particles exerta negative influence on the brittle cracking of the cell wall. The K-edge subtraction technique provides a powerful tool for the quantitative microstructure characterization of three-dimensional tissues.
Design of metamaterial frequency selective surface with polarization selectivity
Authors: Wu Xiang  , Pei Zhi-Bin  , Qu Shao-Bo  , Xu Zhuo  , Bai Peng  , Wang Jia-Fu  , Wang Xin-Hua  , Zhou Hang  ,   College of Science, Air Force Engineering University, Xi’an 710051, China;,   Key Laboratory of Electronic Ceramics and Devices, Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China;,   Synthetic Electronic Information System Research Department, Air Force Engineering University, Xi’an 710051, China
Published: December 2020

Two kinds of frequency selective surfaces with polarization selective characteristics are proposed in this paper. According to the design method of metamaterial, frequency selectivity capability can be achieved by the combination of continuous conducting wire and cut-wire whose effective permittivity is Lorentz-type. By different dimensions and structures in the x-axis and the y-axis of frequency selective surface unit cells, the passband properties for TE and TM waves are separated, so a polarization selective surface in GHz band can be achieved. The design method demonstrates the feasibility of metamaterial frequency selective surface and is of great reference value in fabricating polarization filter and polarization wave generator of specified frequency.
Fiber-based narrow-band single-photon source with high heralding efficiency
Authors: Yang Lei  , Ma Xiao-Xin  , Cui Liang  , Guo Xue-Shi  , Li Xiao-Ying  ,   Key Laboratory of Opto-electronic Information Science and Technology of Ministry of Education, College of Precision Instruments and Optoelectronics Engineering,Tianjin University, Tianjin 300072, China
Published: December 2020

According to the correlated photon pairs produced by spontaneous four-wave mixing in dispersion-shifted fiber, we present a telecom-band single-photon source by using mode-locked laser. Single-photons with a -3 dB bandwidth of 1.1 nm are heralded with more than 50% probability. The measured second-order correlation g(2)(0) is equal to 0.090.01. Our source is well suit for quantum communication systems.
Mechanism for long pulse laser-induced hard damage to the MOS pixel of CCD image sensor
Authors: Bi Juan  , Zhang Xi-He  , Ni Xiao-Wu  ,   School of Science, Changchun University of Science and Technology, Changchun 130022, China;,   School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
Published: December 2020

The interaction process between 1.06 m wavelength Nd:YAG long pulse laser with a millisecond pulse width and the MOS pixel of frame transfer area CCD image sensor and its hard damage mechanism are studied by the finite element method. The thermal-mechanical coupled modeling for long pulse laser irradiation of a MOS pixel is established, and the distributions of temperature and stress are obtained. The results show that the spallations between O layer and S layer appear due to the S layer radial stress on the surface exceeding the compressive strength under the action of the long pulse laser, then it will extend to the entire layer before melting by radial stress,axial stress and hoop stress. Hard damage of pixel occurs as spallation, and one pixel or an array of pixels in the laser irradiation area of CCD sensor is completely in failure. This paper could provide foundation for both laser-induced damage and protection of CCD image sensor.
Effect of PbI2 on optical properties of Te-based far infrared transmitting chalcogenide glasses
Authors: Sun Jie  , Nie Qiu-Hua  , Wang Guo-Xiang  , Wang Xun-Si  , Dai Shi-Xun  , Zhang Wei  , Song Bao-An  , Shen Xiang  , Xu Tie-Feng  ,   College of Information Science and Engineering, Ningbo University, Ningbo 315211, China
Published: December 2020

A novel series of Ge-Te-PbI2 chalcogenide glasses is prepared by traditional melt-quenching method, and the glass-forming region is determined. X-ray diffraction, differential thermal analysis, visible/near-infrared absorption spectroscopy and infrared transmission spectra are adopted to analyze the composition, the structure, and the performance of the Te-based glasses system with an addition of PbI2. The Tauc equation is used to calculate the direct and the indirect optical band gaps, based on the metallization criterion and the band gap energy theory, the relationship between optical band gap and composition is investigated. The results show that with the addition of PbI2, the glasses-forming ability and the thermal stability are improved, Also, the density and the refractive index of glass sample both increase, the short-wavelength edges shift to ward a longer wavelength, the band gap decreases and the infrared cut-off wavelength of glass is 25 m which keeps almost unchanged. The series of glasses can be adopted to fabricate the far-IR optical wave-guide devices.
Numerical study on the optical absorption of one dimension metallic gratings
Authors: Fu Zheng-Ping  , Lin Feng  , Zhu Xing  ,   School of Physics, State Key Laboratory for Mesoscopic Physics, Peking University, Beijing 100871, China;,   National Center for Nanoscience and Nanotechnology, Beijing 100190, China
Published: December 2020

We investigate the reflected response of one-dimensional metallic grating with rigid coupled-wave analysis. Three types of resonance absorptions, i.e., Rayleigh anomaly, surface plasmon polariton (SPP) standing wave resonance and geometric resonance, are identified in the gray-scale map of the reflectivity as a function of two structural parameters: grating period and groove depth. Furthermore, the interactions among these resonances are discussed. Our calculation reveals that a hybrid mode of SPP standing wave resonance and geometric resonance can be found, while no hybrid mode of Rayleigh anomaly and geometric resonance exists. In the analysis of compound gratings, we find phase resonance. How the phase resonance changes the reflection and the absorption of compound metallic gratings is also discussed. When the wavelength of incident light is less than grating period, sharp dip is found in reflectivity as a function of groove depth. In the other case, i.e. Wavelength greater than grating period, phase resonance results in a split of the hybrid absorption branch of SPP standing wave resonance and geometric resonance.
The conserved quantities in general theorems ofthe Cosserat elastic rod dynamics
Authors: Xue Yun  , Wang Peng  ,   School of Mechanical Engineering, Shanghai Institute of Technology, Shanghai 201418, China;,   Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University,Shanghai 200072, China;,   Department of Physics, Xinjiang Normal University, Urumqi 830054, China
Published: December 2020

Conserved quantities of the Cosserat elastic rod dynamics are studied according to the general theorems of dynamics. The rod dynamical equation takes the cross section of the rod as its objective of study and is expressed by two independent variables, the arc coordinate of the rod and the time, so the conserved quantities are written in the integral forms and there exist the arc coordinate conservation and the time conservation. The existence conditions and the formulas of conservations of momentum and moment of momentum are derived from the theorem of momentum and the theorem of moment of momentum respectively, which contain two cases of conserved quanties, one is the time and the other is arc coordinate. Also existence conditions and formulas of conservations of energy about time and are coordinate, which contain mechanical energy conservation, are derived from energy equations about the time and arc coordinate of the rod respectively. All of conservative motions of the rod are explained by examples. The conserved quantities in the integral form are of practical significance in both theoretical and numerical analysis for the Cosserat elastic rod dynamics.
Effects of controllable defects on thermal conductance in a nanowire with a quantum box
Authors: Nie Liu-Ying  , Li Chun-Xian  , Zhou Xiao-Ping  , Cheng Fang  , Wang Cheng-Zhi  ,   School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114, China
Published: December 2020

By using the scattering-matrix method and the scalar model of elasticity, we investigate the effect of controllable defects on low temperature thermal conductance in a nanowire with a quantum box geometry. It is found that the thermal conductance can be controlled by adjusting the parameters of the defects. The size and the position of the defect can induce the variation in thermal conductance. It is also found that the behavior of the thermal conductance versus temperature is different for different types of defects.
Phase transition of atomic chain in the one-dimensional Frenkel-Kontorova model
Authors: Han Xiu-Qin  , Jiang Hong  , Shi Yu-Ren  , Liu Yan-Xiu  , Sun Jian-Hua  , Chen Jian-Min  , Duan Wen  ,   College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China;,   State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000, China
Published: December 2020

The effect of the initial velocity of boundary atom on the motion of an atomic chain is studied by the one-dimensional Frenkel-Kontorova model. The obatined results show that the three phases could be observed in our simulation, these being harmonic phase when vv1, choatic phase when v1vv2 and uniformity phase when vv2. It is aslo shown that the two critical velocites(v1,v2) are strongly influenced by the number of atoms and the depth of the substrate potential.
Mechanism of the influence of the interaction between interstitial H atom and doped atom on the dehydrogenation performance of LiNH2
Authors: Lu Guang-Xia  , Zhang Hui  , Zhang Guo-Ying  , Liang Ting  , Li Dan  , Zhu Sheng-Long  ,   College of Physics Science and Technology, Shenyang Normal University, Shenyang 110034, China;,   State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Published: December 2020

The first-principles plane-wave pseudopotential method based on the density functional theory is used to investigate the mechanism of the influence of interaction between interstitial H atom defect and doped atom on the dehydrogenation performance of LiNH2. We obtain the most stable structure of LiNH2 by geometrical optimization, and calculate the binding-energies, interstitial H atom defect formation energies, densities of states (DOSs), and electric charge populations for LiNH2 and doped LiNH2. Studies show that the results of binding-energy cannot reflect the dehydrogenating properties of LiNH2 and doped LiNH2. In equilibrium, there are a number of interstitial H atom defects; the formation energy of interstitial H atom defect is reduced by doping Mg and Ti, which increases the concentration of interstitial H atoms. Interstitial H atoms can induce the defect energy level in the gap, which reduces the width of the gap, and improves the dehydrogenation performance of LiNH2. The strength of N-H bond in [NH2]- is weakened by interstitial H atom, so that hydrogen atoms in LiNH2 is relatively easy to release. The covalent bond between interstitial H atom and N atom of [NH2]- explains the escape of NH3 from the dehydrogenation reaction of LiNH2 system. The strengths of N-H bonds are not equal in doped LiNH2, a part of N-H bonds are weaker, and other N-H bonds are strong, the hydrogen atoms are easy to release from weaker N-H bonds.
Influence of doped PEDOT ∶PSS on performance of polymer solar cells
Authors: Hao Zhi-Hong  , Hu Zi-Yang  , Zhang Jian-Jun  , Hao Qiu-Yan  , Zhao Ying  ,   Institute of Photo-Electronic Thin Film Devices and Technology, Tianjin Key Laboratory of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Opto-Electronic Information Science and Technology for Ministry of Education, Nankai University, Tianjin 300071, China;,   Institute of Information Functional Material of Hebei University of Technology, Tianjin 300130, China
Published: December 2020

In this paper, we investigate the doping effect on conductivity of poly(3,4-ethylene dioxythiophene):poly (styrenesulphonic acid)(PEDOT ∶PSS)and its influence on performance of polymer solar cell. The experiment demonstrates that the conductivity of PEDOT ∶PSS is improved obviously by doping polar solvent dimethyl sulfoxide (DMSO). The maximum of the conductivity is 1.25 S/cm when the doping concentration reaches 10 wt%, which increases about three orders of magnitude compared with the undoped. Based on doped PEDOT ∶PSS used as an anode buffer layer, the polymer solar cell (ITO/PEDOT ∶PSS/P3HT:PCBM/LiF/Al) shows an improvement of hole charge transport as well as an increase of short-circuit current density and a reduction of series resistance, owing to the higher conductivity of the doped PEDOT ∶PSS. Consequently, it improves the whole performance of polymer solar cell. The short-circuit current density (Jsc) of 11.09 mAcm-2, the open circuit voltage (Voc) of 0.63 V, and the fill factor (FF) of 63.7% are obtained under 100 mW/cm2 air-mass solar simulator illumination, yielding a 4.45% power conversion efficiency ().
Pressure induced band-gap changes in (Ba0.5Sr0.5)TiO3 (BST) from first-principles calculations
Authors: Deng Yang  , Wang Ru-Zhi  , Xu Li-Chun  , Fang Hui  , Yan Hui  ,   Laboratory of Thin Film Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China
Published: December 2020

The high-pressure behaviors of crystalline (Ba0.5Sr0.5)TiO3 (BST) are investigated, using the first-principles calculations based on the density functional theory. The results show that as pressure increases, the band gap of BST first increases and peaks at around 55 GPa, and then gradually decreases. The analysis of density of states shows that in the low-pressure region (0P55 GPa), the increase in band gap is due to the formation of anti-bonding states and bonding states in the conduction band and valence band, respectively. In the high-pressure region (P55 GPa), the delocalization phenomenon in dominant due to the fact that the delocaligation action exceeds the force of bonding state and anti-bonding state, which results in the decrease of the band gap.
An analytical thermal model for 3D integrated circuit considering through silicon via
Authors: Zhu Zhang-Ming  , Zuo Ping  , Yang Yin-Tang  ,   School of Microelectronics, Xidian University, Xi’an 710071, China
Published: December 2020

Based on the one-dimensional analytical thermal model for N strata stacked chips without through-silicon via (TSV), the equivalent thermal model for TSV is presented in this paper. And then, the corresponding analytical thermal model with considering TSV is deriveed. Finally, Matlab software is used to verify and analyze the influence of TSV on the thermal management of 3D IC intergration. The analysis results indicate that the TSV can effectively improve the heat dissipation of 3D IC circuits, and the increase of TSVss pitch can raise the temperature of the 3D IC circuit.
Improved base-collector depletion charge and capacitance model for SiGe HBT on thin-film SOI
Authors: Xu Xiao-Bo  , Zhang He-Ming  , Hu Hui-Yong  ,   Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi’an 710071, China
Published: December 2020

The SiGe heterojunction bipolar transistor (HBT) on thin film SOI is successfully integrated with SOI CMOS by folded collector. This paper deals with the collector depletion charge and the capacitance of this structure. An optimized model is presented based on our previous research. The results show that the charge model is smoother, and that the capacitance model with considering different current flow areas, is vertical and horizontal depletion capacitances in series, showing that the depletion capacitance is smaller than that of a bulk HBT. The charge and capacitance vary with the increase of reverse collector-base bias. This collector depletion charge and capacitance model provides valuable reference to the SOI SiGe HBT electrical parameters design and simulation such as Early voltage and transit frequency in the latest 0.13 m SOI BiCMOS technology.
Spatially chaotic distribution of atoms in Bose-Einstein condensate systems
Authors: Li Fei  , Zhang Dong-Xia  , Li Wen-Bin  ,   Department of Physics, Hunan University of Science and Technology, Xiangtan 411201, China
Published: December 2020

In this paper, we study the spatially chaotic distribution of atoms in a Bose-Einstein condensate system, trapped in an asymmetric periodic potential. For a constant phase of condensate, without atom currents in the system, the space distributed structure of condensated atoms can be described by an undamped Duffing equation with double drivers. Through theoretical analyses, the Mel'nikov chaotic criterion for the system with a repulsive interatomic interaction is presented. Numerical simulations show that an increasing chemical potential can exert considerable suppression on the chaotic distribution of condensated atoms and even completely eliminate chaos. For a system with an attractive interatomic interaction, under some specific parametric conditions, adjusting the ratio between optical lattice potential amplitudes will force the condensated atoms from a periodic state into a spatially chaotic distribution; with the increase of chemical potential, the spatially chaotic distribution is completely suppressed.
Synchronization of fractional chaotic systems based on fractional-order interval systems
Authors: Sun Ning  ,   School of Information Science and Engineering, Northeastern University, Shenyang 110819, China
Published: December 2020

Synchronization of fractional-order chaotic systems is investigated by designing a novel nonlinear feedback controller. Compared with the previous reports, the controlled synchronization error system does not need to turn into a linear system and the performance is improved effectively. Furthermore, a novel sufficient stabilization criterion for fractional-order chaotic systems is proposed by introducing a stabilization criterion of an interval fractional-order linear time-invariant system and using the linear matrix inequality technique. Consequently, the chaotic synchronization is ensured. The simulation result verifies the effectiveness of the proposed method.
Influence of model parameters on properties of strange stars
Authors: Bao Tmurbagan  , Song Tai-Ping  , Cui Jia-Wu  , Tang Gao-Wa  ,   College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, China;,   Library of Nanyang Normal University, Nanyang 473061, China
Published: December 2020

In this paper we mainly investigate, in the framework of effective mass bag model, how the coupling constant and the bag constant execute their effects on equations of state of strange quark matter, and on the properties of strange stars. Numerical results indicate that with the increase of strong coupling constant and bag constant, equations of state for strange quark matter turn softened, whereas gravitational mass and corresponding radius of strange stars become decreased. For instance the mass of the star decreases from 1.43M⊙(M⊙=1.991030 kg)to 1.25M⊙ and corresponding radius decreases from 8.3 km to 7.7 km while the coupling constant varies from 0.5 to 2.0. As for strange stars, the corresponding values decrease from 1.47M⊙to 1.22M⊙ and 8.6 km and 7.4 km respectively while the bag constant B1/4 increases from 160 MeV to 175 MeV.
Isotope interchange reaction dynamics of the T+OD system
Authors: Zhu Zhi-Yan  , Zhu Zheng-He  , Zhang Li  , Li Pei-Gang  , Tang Wei-Hua  , Zheng Ying-Ying  ,   Center for Optoelectronics Materials and Devices, Zhejiang Sci-Tech University, Hangzhou 310018, China;,   Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

The atomic and molecular reaction dynamics for T+OD have been studied basad on the potential energy function of DTO(1 A1) by Monte Carlo quasi-classical trajectory approach. It is shown that the reaction T+ODDTO with a long-lived complex has a threshold energy at low collision energy, which accords with the potential curve. The interchange reaction increases with collision energy increasing, until the DTO molecules decompose into D, T, and O completely, and these reactions have threshold energyies too. The trajectories and the collision cross-sections of T+OD(0, 0) and D+OT(0, 0) are different due to the isotopic effect of D atom and T atom.
Multireference configuration interaction study on spectroscopic parameters and molecular constants of AsN(X1 +) radical
Authors: Wang Jie-Min  , Sun Jin-Feng  ,   College of Physics and Electronic Information, Luoyang Normal College, Luoyang 471022, China;College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
Published: December 2020

The potential energy curve (PEC) of the AsN(X1 +) radical is investigated by the highly accurate valence internally contracted multireference configuration interaction method in combination with the correlation-consistent basis sets, aug-cc-pV5Z for As and aug-cc-pV6Z for N atom. The PEC is fitted to the Murrell-Sorbie function, which is used to accurately derive the spectroscopic parameters. The parameters De, Re, e, exe, e and Be are obtained to be 4.97 eV, 0.16259 nm, 1061.14, 5.4715, 0.53919, 0.003409 cm-1 respectively; which accord well with the available measurements. With the obtained PEC of AsN(X1 +), a total of 67 vibrational states are predicted when J=0 for the first time by numerically solving the radical Schrdinger equation of nuclear motion. For each vibrational state, the vibrational level, the classical turning points, the inertial rotation and the centrifugal distortion constants are completely reported for the first time.
A coherently combined laser beam for lidar
Authors: Lian Tian-Hong  , Wang Shi-Yu  , Guo Zhen  , Li Bing-Bin  , Cai De-Fang  , Wen Jian-Guo  ,   School of Technical Physics, Xidian University, Xi'an 710071, China
Published: December 2020

A fundamental way to improve the ability of lidar to detect the small target far away is to increase the light intensity on it, and the coherent combination of laser beams is an effective way to obtain a large intensity on the target. A parameter named combining effect factor is introduced to evaluate the combining effect on small target. On this basis, the factors influencing combining effect are discussed. The combining effect factor becomes oscillatory as the spacing between the waists of laser beams increases, and its amplitude decreases gradually. The distance at which an ideal combining effect can be achieved increases with the increase of the spacing between the waists of laser beams, which is a reference for the determination of the spacing between the waists of laser beams in the design of coherent combining system. The dependence of combining effect on the phase control accuracy is also studied. The combining effect can reach 80 percent of its ideal value when the phase control accuracy reaches /4, and the combining effect decreases to 50 percent of its ideal value when the accuracy is /2. The influence of unparallel polarization direction between beams on combining effect is not very obvious.
Optimization of electro-optical parameter of optical frequency standard system based on modulation transfer spectroscopy technique
Authors: Jia Yu-Dong  , Lin Zhi-Li  , Ou Pan  , Zhang Chun-Xi  ,   School of Instrument Science and Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
Published: December 2020

According to the mechanism of nearly degeneration four-wave mixing that occurs in a sufficiently nonlinear resonant gaseous medium caused by phase-modulated laser beam, the electromagnetism excitation and dynamic evolvement of modulation transfer spectroscopy(MTS) technique is studied theoretically, and then mathematic models of dispersion spectrum and absorption spectrum of MTS are established too. The results show that when the frequency of modulation signal source is equal to 0.72 times the linewidth of absorption line approximatively, the intensity of dispersion signal reaches a maximum value; it can obtain a better frequency-stabilization result when modulation factor is set to be nearly 0.3; the instability of demodulation phase has a big effect on the absorption spectrum, but on dispersion spectrum, the effect is tiny when the demodulation phase fluctuates near 90.
The influence of point defect array on directional emission of phononic crystal waveguide
Authors: Wei Qi  , Cheng Ying  , Liu Xiao-Jun  ,   Institute of Acoustics, Nanjing University, Nanjing 210093, China
Published: December 2020

A novel composite waveguide is proposed to improve the directional emission of phononic crystal waveguide by introducing a point defect array. The finite element simulations indicate that the point defects attached to the output surface of phononic crystal waveguide produce resonant modes, which act as secondary radiation sources. The interferences of sound wave radiated from these radiation sources and waveguide can enhance the normal radiation intensity by 161.21% and reduce the half-power angular width by 85.35%. In addition, when the number of the point defects is large enough, the directivity approaches a steady value. The investigation provides a new method to improve the directional emission of phononic crystal waveguide.
Acoustic phonon transport and thermal conductance in one-dimensional quantum waveguide modulated with quantum dots
Authors: Peng Xiao-Fang  , Wang Xin-Jun  , Gong Zhi-Qiang  , Chen Li-Qun  ,   College of Science, Central South University of Forestry and Technology, Changsha 410004, China
Published: December 2020

By using scattering matrix method, we compare the propertics of acoustic phonon transport and thermal conductance in one-dimensional quantum waveguide modulated with both convex-shape and concave-shape quantum structures. The results show that the transmission spectra and thermal conductances are sensitive to the geometric structures of quantum dots, and the transmission rate and thermal conductance KCV in the convex-shape quantum structure are bigger than the transmission rate and thermal conductance KCC in the concave-shape quantum structure. The thermal conductance ratio KCV/KCC is dependent on the geometric detail of quantum dot, and the ratio increases with the increase of difference in side-length of the cross section between the quantum dot and the main quantum waveguide. The difference in thermal transport between the convex-shape and the concave-shape quantum structures originates from more excited dilatational acoustic modes in the convex-shape quantum structure than in the concave-shape quantum structure.
Ferromagnetism properties in nitrogen-doped titanate: A first principles calculations
Authors: Tan Xing-Yi  , Chen Chang-Le  , Jin Ke-Xin  , Chen Peng  ,   Key Laboratory of Condensed Matter Structures and Properties of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710129, China
Published: December 2020

Based on the density functional theory, the electronic properties of N-doped titanates are investigated. It is found that the titanate doped by a nonmagnetic 2p light element N is ferromagnetic. The local magnetic moment is localized mainly on doped N atoms. Our results indicate that the N-doped titanates may be potential candidates for dilute magnetic semiconducting materials and multiferric materials.