bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the influence of process parameters on the synthesis of AlON-TiN composites by using support vector regression
Authors: Wen Yu-Feng  , Cai Cong-Zhong  , Pei Jun-Fang  , Zhu Xing-Jian  , Xiao Ting-Ting  , Wang Gui-Lian  ,   重庆大学应用物理系，重庆  400044
Published: December 2020

According to the experimental dataset on the bending strength of AlON-TiN composite synthesized by hot pressing sintering approach under different processing parameters, i.e., mass fraction of TiN, sintering temperature and soaking time, the support vector regression （SVR） approach combined with particle swarm optimization for its parameter optimization, is proposed to simulate the relationship between the bending strength and hot pressing sintering synthesis parameters of AlON-TiN composites. The optimization of process parameters and the multi-factor analysis are also carried out. The prediction result demonstrates that the estimation error of the SVR model is less than that of the artificial neural network（ANN） model under the identical training and test samples and reveales that the generalization ability of SVR model surpasses that achieved by the ANN model. The optimal synthesis parameters are obtained numerically under TiN content 13.5%, sintering temperature 1863.5 ℃ and soaking time 5.8 h. The maximum bending strength is estimated to be 555.452 MPa while the AlON-TiN composite is synthesized at the optimal synthesis parameters. These results suggest that SVR can provide an important theoretical and practical guidance to the research and development of AlON-TiN composite possessing ideal bending strength.
Phase field simulation on recrystallization and secondary phase precipitation under strain field
Authors: Zong Ya-Ping  , Wang Ming-Tao  , Guo Wei  ,   东北大学材料各向异性与织构教育部重点实验室，沈阳  110004
Published: December 2020

General theory and formula of phase field simulation are discussed to as certain physical meanings of some phenomenological parameters in the basic model. A new concept of boundary range is suggested to explain the physical backgrounds of the phase order parameter gradients at grain boundary and the diffusion grain boundary, separately. It is argued that the boundary range is not the geometrical boundary width of atom disorder and generally believed to be within 3—4 atom sizes. However, the range has an independent boundary feature to represent the grain boundary energy distribution range in which the solute alloy atoms are segregated from interior grain. A model is established to simulate the realistic spatio-temporal microstructure evolution in recrystallization of a magnesium alloy by using the phase field approach. A set of rules has been proposed to determine the real physical value of all parameters in the model. The simulated results are shown to be in good agreement with reported measurements at the temperatures from 300 to 400 ℃ for up to 100 min. The effect of applied strains field on the microstructure produced during α2 phase to O-phase （orthorhombic phase） transformation in Ti-25Al-10Nb alloy is finally studied by phase field simulation. The effects of strain direction on the volume fraction of O-phase and on the microstructure are investigated. It is also found that a full laminar microstructure can be formed when the applied strain is loaded along 〈1120〉 of α2 phase with magnitude greater than a half of the stress-free transformation strain. The significance and the potential application of the new simulation discovery are discussed.
Physical model and simulation system of powder packing
Authors: Zhong Wen-Zhen  , He Ke-Jing  , Zhou Zhao-Yao  , Xia Wei  , Li Yuan-Yuan  ,   (1)华南理工大学机械与汽车工程学院，广州  510641; (2)华南理工大学计算机科学与工程学院，广州  510641
Published: December 2020

The physical model and the computational system for powder packing process simulation are presented, and the high performance computing methods of simulating the random packing of mixed particles with different sizes are studied. In the simulation system the effects of gravity, contact forces, damping, friction, van der Waals force etc are take into account, therby forming several kinds of mechanical models and damping models. The system is very suitable for the three\|dimensional simulation of large scale powder packing process. Finally, to demonstrate the usefulness of the simulation system, two typical applications are presented in the paper. One is to simulate the random packing of binary mixture with size ratio 10, and when the number of small particles is 300 times as large as that of big particles, the maximal packing density （volume fraction） is achieved to be 0.824, and the other is to simulate the random mixed packing dynamics of particles with two different densities. The segregation phenomenon and clustering phenomenon take place obviously after the packing process has come to an end. The physical model and the simulation system presented in this paper are not only suitable for the study of powder packing process, but also applicable to the packing process simulation of spherical objects.
Electronic structure and mechanical properties of α-Mg3Sb2
Authors: Yu Wei-Yang  , Tang Bi-Yu  , Peng Li-Ming  , Ding Wen-Jiang  ,   (1)上海交通大学材料科学与技术学院，轻合金精密成型国家工程研究中心，上海  200030; (2)湘潭大学材料与光电物理学院，低维材料及其应用技术教育部重点实验室，湘潭  411105; (3)湘潭大学材料与光电物理学院，低维材料及其应用技术教育部重点实验室，湘潭  411105；广西大学化学与化工学院，南宁  530004
Published: December 2020

First principles calculations have been carried out to investigate the electronic structure and the mechanical properties of α-Mg3Sb2. The optimized structural parameters and formation energy are in good agreement with the experimental values. The electronic structure is also given， indicating that α-Mg3Sb2 is indirect-semiconductor. The obtained energy band gap of α-Mg3Sb2 is 0.303 eV. The elastic constaint Cij of α-Mg3Sb2 has been calculated，then the mechanical parameters such as moduli, Possions ratio, etc are abtained. By analysizing the mechanical parameters it is found that α-Mg3Sb2 has good ductility and relatively poor plasticity. In the end，the volume conservation of α-Mg3Sb2 is discussed in terms of the total density of states before and after deformations. From the results， it can be seen that the shears corresponding to （C11-C12）/4 and C44 are almost volume conserving whereas the shears corresponding to C11+C12，C33/2 and the bulk modulus related to C11+C12+2C13+C33/2 are not volume conserving.
Modelling of solutal dendritic growth in three dimensions
Authors: Pan Shi-Yan  , Zhu Ming-Fang  ,   东南大学江苏省先进金属材料高技术研究重点实验室，南京  211189
Published: December 2020

A three-dimensional （3D） model for the simulation of solutal dendritic growth in the low Pclet number region is presented. In the model is adopted a solutal equilibrium approach previously proposed by Zhu and Stefanescu to calculate the evolution of the solid/liquid（SL） interface， which allows the accurate simulation of dendritic growth from the initial unstable stage to the steady-state stage with a good computational efficiency. In this approach， the kinetics of dendritic growth is driven by the difference between the local equilibrium composition， calculated from the local temperature and curvature， and the local actual liquid composition，obtained by solving the solutal transport equation. To describe the specific crystallographic orientation of 3D dendritic growth， a weighted mean curvature （WMC） algorithm， which is incorporated with the anisotropy of surface tension， is proposed to calculate the local SL interface curvature. This approach is convenient to be implemented and to make the transformation for WMC calculation from two to three dimensions. The model is verified by the comparison of our numerical resuets with the analytical ones. The simulated steady-state tip velocity and radius varying with the degree of undercooling of an Al-2wt%Cu alloy are found to be close to the ones predicted by the Lipton-Glicksman-Kurz analytical model. The steady-state morphology of the needle dendrite tip is analyzed. It is found that the tip is nonaxisymmetric and deviates from a paraboloid in the manner of the fourfold symmetry. Finally， the simulated 3D multi-equiaxed dendrites with various crystallographic orientations are presented.
Lattice dynamics of hydrogen-substituted graphene systems
Authors: Huang Liang-Feng  , Li Yan-Ling  , Ni Mei-Yan  , Wang Xian-Long  , Zhang Guo-Ren  , Zeng Zhi  ,   中国科学院固体物理研究所材料物理重点实验室，合肥  230031
Published: December 2020

The hydrogen substituted graphenes are investigated by using the density-functional theory. And the localized vibrational modes（LVMs） are calculated within the framework of density-functional perturbation theory. It is found that the number of LVMs at high-frequency part of the spectrum is equal to the number of hydrogen atoms in one vacancy，and LVMs from samples with different substituents have different frequencies. The results and analyses indicate that the measuring of LVMs is an efficient method to determine the classification of substituents as well as their corresponding concentrations in proton-irradiated graphene/graphite samples. This method can also be applied to other doped systems.
Microscopic phase field simulation on the nucleation incubation period of L12 and D022 phases in Ni75Cr25-xAlx alloy
Authors: Lu Yan-Li  , Chen Zheng  , Lai Qing-Bo  , Zhang Jing  ,   西北工业大学材料学院，西安  710072
Published: December 2020

Based on the microscopic phase field dynamic model， the effect of Al concentration on the nucleation incubation period of Ni75Cr25-xAlx alloy and the relation between the incubation period and the precipitation sequence are investigated by using the atomic pictures， averaged long-range order parameters and averaged composition deviation order parameters. The simulation results show that the nucleation incubation periods of L12 and D022 phases are related not only to the Al concentration but also to the precipitation sequence. When the Al concentration is smaller than 7.5%， for the D022 phase first precipitated from the matrix, its nucleation incubation period becomes longer with the increase of Al concentration, and so is the L12 phase subsequently precipitated. When the Al concentration is larger than 7.5%， for the L12 phase first precipitated from the matrix， its nucleation incubation period become shorter with the increase of Al concentration， so is for the D022 phase subsequently precipitated. When the Al concentration is equal to 7.5%， L12 and D022 phases both precipitate almost simultaneously， and there is no obvious difference berween their nucleation incubation periods.
A method of fitting shell model interatomic potential for H2 molecule from electronic structure data
Authors: Wang Xun  , Liu Yan-Xia  , Wang Yue-Hua  , Ma Zhen-Ning  , Shan Ya-Na  , Wang Jing-Yu  ,   (1)辽宁大学物理学院，沈阳  110036; (2)沈阳建筑大学理学院，沈阳  110168
Published: December 2020

The shell model interionic and interatomic potentials are widely used to perform atomistic simulations of ionic crystals. The parameters of the potentials are obtained by fitting the data from measurements and/or electronic structure calculations of the crystal discussed. A new method of fitting shell model interatomic potential is presented for diatomic molecule from electronic structure data obtained by quantum chemical ab initio calculation in the paper. And the shell model interatomic potential for H is fitted from the electronic structure data of H2 molecule for example. To examine the method, the interatomic potential and force of H+2 molecular ion are calculated from the potential functions. The results demonstrate that the proposed new fitting procedure shows a fairly good feasibility to the shell model potential for covalent bond molecule.
Molecular dynamics study on structural change of a Au959 cluster supported on MgO(100) surface at low temperature
Authors: Zhang Lin  , Zhang Cai-Bei  , Qi Yang  ,   东北大学理学院,沈阳  110004
Published: December 2020

Structural change of a Au959 cluster supported on the MgO（100） surface at a low temperature of 10 K is investigated by molecular dynamics simulation based the on atomic interchange potentials of the metal/MgO interface, where the parameters are from the ab initio energies obtained based on Chen-Mbius inversion method. The analyses on paired atoms and pair distribution functions show that there exists a deformation process in the Au cluster to adjust the interatomic distance of the interface atoms, owing to the mismatching of the interatomic distancs in the cluster to those in the substrate. After the adjustment of atomic positions, the volume of the supported Au cluster becomes larger than its unsupported counterpart.
Structural changes during freezing and coalescing of small sized clusters on atomic scale
Authors: Zhang Lin  , Xu Song-Ning  , Li Wei  , Sun Hai-Xia  , Zhang Cai-Bei  ,   (1)东北大学理学院,沈阳  110004; (2)东北大学理学院,沈阳  110004；沈阳理工大学理学院，沈阳  110168
Published: December 2020

Structural changes of three molten CuN（N=57,58,59） clusters during freezing and two Cu55 clusters with perfect icosahedral geometries in the coalescence processing at 300 K are investigated by molecular dynamics simulations based on the embedded atom method. Simulation results show that both freezing and coalescing processes have distinct stages. There exist great differences in atomic movement and microstructure change among the three CuN（N=57,58,59） clusters during freezing, which result in the different patterns of atomic packing in the three clusters. Of the three clusters, the ordered degree of the Cu59 cluster is the lowest. Initially structural changes of the two Cu55 cluster during coalescence result from large position displacements of atoms due to the deformation, then the atomic diffusion plays a mainly role in changing structure. The atoms far from the contact region between the two clusters can remain their origin structures.
Infinitely many symmetries and symmetry reduction of (2+1)-dimensional generalized Calogero-Bogoyavlenskii-Schiff equation
Authors: Zhang Huan-Ping  , Chen Yong  , Li Biao  ,   宁波大学数学系，宁波  315211
Published: December 2020

Integrability condition of （2+1)-dimensional generalized Calogero-Bogoyavlenskii-Schiff equation are obtained by Painléve-test. Based on this condition and Painléve-test, the bilinear form of GCBS equation is found. Towards this bilinear form infinitely many formal series symmetries are found by the formal series symmetry method, the obtained symmetries are used to get the symmetry reductions of GCBS equation.
Variational iteration method for solving a class of strongly nonlinear evolution equations
Authors: Mo Jia-Qi  , Zhang Wei-Jiang  , Chen Xian-Feng  ,   (1)安徽师范大学数学系,芜湖  241000；上海高校计算科学E-研究院上海交通大学研究所,上海  200240; (2)上海交通大学数学系,上海  200240；上海高校计算科学E-研究院上海交通大学研究所,上海  200240
Published: December 2020

A class of strongly nonlinear evolution equations are studied. Using the variational iteration method, the corresponding varationa is first constructed,then the suitable initial approximation is selected; and then, by using the iteration method, the approximate solution of arbitrary degree of accuracy for the solitary wave is obtained.
Dispersion relation and Landau damping of linear waves in quantum plasma
Authors: Ji Pei-Yong  , Lu Nan  , Zhu Jun  ,   上海大学物理系，上海  200444
Published: December 2020

The dispersion relation and Landau damping of electron plasma waves in the quantum plasma are derived by kinetic theory. Starting from the quantum hydrodynamic equation of electron and photon kinetic equation, photon Landau damping is discussed. Research indicates that quantum effects enlarge the frequency of electron plasma waves and do not change the dispersion of electromagnetic waves. It is also found that electron and photon Landau damping rates are both reduced by quantum effects, so the exchange of energy between particles and waves is retarded.
Effect of the position of accident on traffic waves
Authors: Zhao Shou-Gen  ,   北京航空航天大学航空科学与工程学院,北京  100191
Published: December 2020

In this paper, we adopted the traffic flow model with the consideration of the accident probability, which is recently developed by Tang et al. （Tang T Q, Huang H J, Xu G 2008 Physica A 387 6845）, to study the effect that the accident position has on shock and rarefaction wave. The simulation results show that our model can perfectly reproduce the effects that the accidental position produces on the two traffic waves and the effects are completely related to the accident position.
An extension system with constant Lyapunov exponent spectrum and its evolvement
Authors: Li Chun-Biao  , Wang Han-Kang  ,   (1)江苏经贸职业技术学院工程技术学院，南京  210007；江苏省食品安全工程技术研究开发中心电源与系统部，南京  210007; (2)江苏省食品安全工程技术研究开发中心电源与系统部，南京  210007
Published: December 2020

By introducing linear terms and constant terms in dynamic equations, the extension system with constant Lyapunov exponent spectrum is proposed based on the improved constant-Lyapunov-exponent-spectrum system. Firstly, the dynamical behaviour of the extension system is investigated and expounded by simulation of Lyapunov exponent spectrum, bifurcation diagram and numerical analysis on amplitude evolvement of state variables. Secondly, a class of subsystems with the same properties but different phase trajectories is obtained through different combinations of linear terms from the extension system. The dynamical characteristics including equilibrium, eigenvalue and Lyapunov exponents are analyzed in detail simultaneously. Finally, it is pointed out that the chaotic system will have a tremendous application prospect in chaotic radar, secure communications and other information processing systems.
A new method of adaptive tracking control for chaotic system
Authors: Luo Xiao-Hua  , Li Hua-Qing  , Chen Qiu-Hua  ,   (1)重庆邮电大学数理学院,重庆  400065; (2)重庆邮电大学通信与信息工程学院,重庆  400065
Published: December 2020

In this paper, a new strategy of adaptive tracking control of chaotic system is proposed.By designing the compensatory controller in advance, this method transforms the tracking control problem of reference signals which are tracked by chaotic system states variables into the adaptive synchronization problem of identical-structured chaotic system variables. Tracking controller is equal to the sum of compensatory controller and adaptive controller.Truth of tracking controller designed by proposed strategy is proved theorically based on Lyapunov stability theory.Finally, taking hyperchaotic Chen system as controlled object, tracking controllers are designed in this way to track fixed points, sine signals, cosine signals, identical-structured chaotic system state variables and different-structured chaotic system state variables. The response time is very short, showing the effectiveness of the strategy.
The perimeter measure analysis of chaotic attractor morphology of inclined oil-water two phase flow patterns
Authors: Zong Yan-Bo  , Jin Ning-De  , Wang Zhen-Ya  , Wang Zhen-Hua  ,   天津大学电气与自动化工程学院,天津  300072
Published: December 2020

In two-dimensional phase space, the attractor morphology parameters of perimeter measures, such as area, lengths of long axis and short axis, are defined, and the variations of these parameters with the delay time are investigated. It was found that the growth rates of the above parameters do not change notably in the first zone during the attractor unfolding process, which is suitable for attractor morphology characterization. The classification effectiveness of this method is verified by applying it to simulating signals, such as sine signal, white noise, mixed signals and Lorenz signals. By the experiment of inclined oil-water two phase flow, the conductance signals were acquired from the vertical multi-electrode array sensor, and the water dominated inclined oil-water flow patterns are analyzed by using the attractor morphology parameters and we found that the growth rate of area is an invariant quantity of attractor morphology, which can give a good classification of dispersion of oil in water-pseudoslugs flow and dispersion of oil in water-countercurrent flow.
Output feedback adaptive maneuvering for multi-input multi-output uncertain nonlinear systems
Authors: Zhou Ying  , Zang Qiang  ,   (1)南京信息工程大学信息与控制学院，南京  210044; (2)南京邮电大学自动化学院，南京  210003
Published: December 2020

The output maneuvering problem generally consists of geometric task and dynamic task. In this paper, the adaptive maneuvering control based on output feedback is studied for multi-input multi-output nonlinear system with parametric uncertainty. The virtual estimation of the controlled system states is achieved by introducing filters and observer. Based on the backstepping approach in vector form, an output feedback adaptive maneuvering control scheme is proposed and three kinds of adaptive laws governing the path variable are presented. The geometric and the dynamic tasks are solved, meanwhile the global stability of the closed loop systems is guaranteed through the control scheme. The simulation results show the effectiveness of the proposed scheme.
Reflection of plane wave in oscillatory media
Authors: Lü Yao-Ping  , Gu Guo-Feng  , Lu Hua-Chun  , Dai Yu  , Tang Guo-Ning  ,   广西师范大学物理与电子工程学院，桂林  541004
Published: December 2020

The reflection of plane waves in oscillatory media described by complex Ginzburg-Landau equation has been researched. The reflection condition and the angle formed by the boundary line between incident and reflected waves and the boundary line separating two regions of different kinetics are theoretically given. Two kinds of reflections have been found. One is a back refraction-induced reflection. The corresponding angle is theoretically obtained. The other is a pure reflection, which is independent of refraction. The theoretical results are supported by numerical results. The theoretical and numerical results show that the reflection takes place only if the angle of incidence is larger than a critical value. The angle of reflection is equal to the critical angle of incidence, and it increases as the frequency of the incident wave increases for the pure reflection.
Investigation on traffic bottleneck induce by bus stopping with a two-lane cellular automaton model
Authors: Li Qing-Ding  , Dong Li-Yun  , Dai Shi-Qiang  ,   上海大学上海市应用数学和力学研究所，上海  200072
Published: December 2020

In this paper, the influence of typical bus stops on traffic flow is investigated with the cellular automaton traffic model. For on-line and off-line bus stops, a two-lane cellular automaton model is proposed to simulate the traffic bottleneck induced by bus stopping under the open boundary condition. The phase diagram in the phase plane of injection probability and bus fraction is provided and two phases, i.e., the free flow phase and congested flow phase, are distinguished. The distributions of the mean density and velocity near the bus stop in different traffic phases are given and the comparison of dynamical characteristics of traffic flows is made for different types of bus stops. It is found that using the off-line bus stop can significantly improve the traffic flow in its neighboring region, compared with the on-line bus stop in the case of small fraction of buses.
Multi-vapor embryos nucleation process and spinodal temperature analysis of expandable superheated water system
Authors: Li Si-Jie  , Bai Bo-Feng  ,   西安交通大学动力工程多相流国家重点实验室，西安  710049
Published: December 2020

This study uses molecular dynamics simulation to analyze the homogeneous nucleation process in superheated water. The temperature and pressure of the system are controlled with Langevin dynamics method while the system volume is variable. In this way, the expanding process of the liquid system into vapor system is studied phenomenologically. In metastable liquid system with higher superheating degree, there can be seen large quantities of regions with no liquid moleculer inside: i.e., the vapor embryos. These vapor embryos are unstable in nature and are deforming with time. By analyzing the attraction and repulsion between molecules, we find the mechanisms that govern the merging, formation and dying out of vapor embryos. Vapor embryo violates some predictions of classical bubble dynamics theory, it indicates that formation of vapor embryo may have a more microcopic nature than the formation of bubble. We compared systems under different temperatures to study the effects of superheating degree. The spinodal temperature of water at atmospheric pressure determined under our simulation condition is about 535 K, within the scope of available experimental results.
Propagation of femtosecond laser pulses through metal-coated tapered fibre probe
Authors: Liu Gui-Yuan  , Teng Shu-Yun  , Cheng Chuan-Fu  , Song Hong-Sheng  , Liu Man  ,   (1)山东师范大学物理与电子科学学院，济南  250014; (2)山东师范大学物理与电子科学学院，济南  250014；山东建筑大学理学院，济南  250101; (3)山东师范大学物理与电子科学学院，济南  250014；山东轻工业学院数理学院，济南  250353
Published: December 2020

Using the three-dimensional finite difference time domain （3D-FDTD） method, we calculate light field in metal-coated optical fiber probes with different taper angles and different lengths under illumination of femtosecond laser pulses. The transmission of temporal fields of the laser pulses propagating in the probes and the properties of their frequency spectrum and phases are studied. The influences of the taper angle and the length of the probe on these properties are analyzed. The calculation results show that the structure of probe leads to the broadening, amplitude oscillation and the spectrum splitting of the laser pulses. With the analysis of the spectrum and the phase variation, we give a preliminary explanation to the phenomena of the pulse broadening and the periodic variation of the pulse amplitude with time.
Calculation of fine-structure intervals of nd series high Rydberg states of Na
Authors: Ma Yi-Pei  , He Li-Ming  , Zhang Meng  , Zhu Yun-Xia  ,   华东理工大学物理系，上海  200237
Published: December 2020

A new numerical calculation method has been used to solve the relativistic Hartree-Fock （RHF） equation of atomic system. The retardation term in Breit interaction was given in a explicit and succinct formulation. The established theoretical method and computational program have been used to study the fine structure of nd（n=17—31） series of sodium. We obtained the fine structures by using RHF method in a self- consistent procedure for the first time, rather than perturbation method often used by other authors. The results show that the exchange interaction between the core and valence electrons in the frame of relativity is the main reason of abnormal fine structure. By combining the effect of Breit interaction, it is shown that a relativistic calculation reproduces the inverted fine structure of sodium exactly and our work is far better than other theoretical results.
Role of potential function in high order harmonic generation of model hydrogen atoms in intense laser field
Authors: Li Hui-Shan  , Li Peng-Cheng  , Zhou Xiao-Xin  ,   (1)西北师范大学物理与电子工程学院，兰州  730070; (2)西北师范大学物理与电子工程学院，兰州  730070；青海大学基础部，西宁  810016
Published: December 2020

By constructing one-dimensional model potential function with variable parameters, we investigate the high order harmonic generation （HHG） of one-dimensional model hydrogen atoms and real hydrogen atom with same ground state energy in 1 cycle and 16 cycles of intense laser fields. Our results show that in the over-barrier ionization region, the intensities of HHG for one-dimensional model atoms with different potential parameters are closely related with the depth of the potential well, but independent of the Coulomb singularity of the potential.
Elastic collision between S and D atoms at low temperatures and accurate analytic interaction potential and molecular constants of the SD(X2Π) radical
Authors: Shi De-Heng  , Zhang Jin-Ping  , Sun Jin-Feng  , Liu Yu-Fang  , Zhu Zun-Lüe  ,   (1)河南师范大学物理与信息工程学院，新乡  453007; (2)信阳师范学院物理电子工程学院，信阳  464000
Published: December 2020

The equilibrium internuclear separations, harmonic frequencies and interaction potentials have been calculated by employing the CCSD（T） theory in combination with the series of the correlation- consistent basis sets, cc-pVnZ and aug-cc-pVnZ （n=2, 3, 4, 5）, of Dunning and co-workers. The potential energy curves are all fitted to the Murrell-Sorbie functions, which are used to determine the spectroscopic parameters. At the CCSD（T）/aug-cc-pV5Z level of theory, the values of D0, De, Re, ωe, αe, B0 are 3.65730 eV, 3.77669 eV, 0.13424 cm－1, 1938.372 cm－1, 0.09919 cm－1, 4.88585 cm－1 and 4.8872 cm－1, respectively, which conform almost perfectly with the available measurements. With the analytic interaction potential obtained at the CCSD（T）/aug-cc-pV5Z level of theory, a total of 23 vibrational states has been predicted for the first time when the rotational quantum number J is set to equal zero （J=0） by solving the radial Schrdinger equation of nuclear motion. The complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are reproduced from the SD（X2Π） potential when J=0 The total and various partial-wave cross sections are calculated for the elastic collisions between the ground-state S and D atoms at energies from 1.0×10-11 to 1.0×10-4 a.u. when the two atoms approach each other along the SD（X2Π） interaction potential. No shape resonances can be found in the total elastic cross sections. The results show that the shape of the total elastic cross sections is mainly dominated by the s-partial wave at very low temperatures. Because of the weakness of the shape resonances coming from various partial waves, they are all covered up by the strong total elastic cross sections.
Coherence length tunable semiconductor laser
Authors: Kong Ling-Qin  , Fan Lin-Lin  , Wang An-Bang  , Wang Yun-Cai  ,   太原理工大学理学院物理系，太原  030024
Published: December 2020

We report a technique for continuous tuning the coherence length of semiconductor laser. The coherence length of the semiconductor laser is controlled by using optical feedback scheme. The results show that the coherence length of semiconductor laser can be shortened from several meters of the original solitary laser to 100 μm by the implementation of optical feedback. Experimental results indicate that the coherence length of the laser depends strongly on the feedback strength， but is insensitive to the bias current. The results of numerical simulations using rate equation of semiconductor laser are fully consistent with our experimental results.
Quantitative analysis on median-time-to-fail of copper interconnect with lose object defects
Authors: Zhou Wen  , Liu Hong-Xia  ,   西安电子科技大学微电子学院，宽禁带半导体材料与器件教育部重点实验室，西安  710071
Published: December 2020

In the paper， influence of lose object defects on electromigration median-time-to-failure （MTF） for six-layer copper interconnect is investigated. The temperature model with defects for each interconnection layer and MTF model for defects in different interconnection layers are presented respectively. So， the defect influence on electromigration MTF of copper interconnect can be calculated quantitatively， and the method to increase MTF is also presented. The bigger the ratio of interconnect width to the effective interconnect width at the defects， the shorter the MTF， and higher temperature at defects can also shorten the MTF. When the parameters of interconnect wire vary greatly between different layers， the MTF is affected by the ratios and the temperature， and decreases rapidly. Based on the physical model， the temperature and the MTF of copper interconnect can be calculated accurately， which can guide IC design and manufacture effectively.
An Yb-doped large-mode-area photonic crystal fiber mode-locking laser with free output coupler
Authors: Zhang Chi  , Hu Ming-Lie  , Song You-Jian  , Zhang Xin  , Chai Lu  , Wang Qing-Yue  ,   天津大学精密仪器与光电子工程学院超快激光研究室，光电信息技术科学教育部重点实验室,天津  300072
Published: December 2020

The theoretical and experimental study of an Yb-doped double clad large mode area photonic crystal fiber laser is reported. This fiber laser system uses one facet of the fiber directly as a cavity mirror， which is fine-polished to 0° angle after collapsing. Lasing is obtained with the feedback of this facet， and mode-locking is achieved by using a semiconductor saturable absorber as another cavity mirror and adding a grating-pair as the spectral filter. By adjusting the filtering conditions， continuous tuning from wide filtering condition to narrow filtering condition is achieved. Under the wide filtering condition， the system generates femtosecond pulses， the highest average power of which is 2.2 W， corresponding to 29.3 nJ pulse energy and 367 fs pulse duration; under the narrow filtering condition， it generates picosecond pulses， the highest average power of which is 4 W， corresponding to 53.3 nJ pulse energy and 1.14 ps pulse duration. In numerical simulation， the evolution and cavity-position-related characteristics of pulses are studied by using split-step Fourier method.
Transmission property of elastic wave through one-dimensional compound materials
Authors: Cao Yong-Jun  , Yang Xu  , Jiang Zi-Lei  ,   内蒙古师范大学物理与电子信息学院，呼和浩特  010022
Published: December 2020

The models of elastic waves in one-dimensional compound materials， including one-dimensional periodical phononic crystals， abnormal Fibonacci qusi-periodical phononic crystals， generalized Fibonacci qusi-periodical phononic crystals and absolutely disordered compound materials， are proposed in this paper. The transmission coefficients of elastic waves through the above systems are numerically calculated using the mode matched theory method. The results shows that larger band gap can be obtained， and much more localized modes are present in the band gap of a given quasi-periodical structure phononic crystals than in the periodical phononic crystals. The effect of quasi-periodical structure is the same as that of the prcsence of defects in periodical phononic crystals. The study of the localized states of elastic waves/acoustic waves in compound materials is useful to the fabrications of the elastic/acoustic wave filters or wave-guides.
Variable charge molecular dynamics simulations of the intergranular films in SiC
Authors: Ma Ying  , Chen Shang-Da  , Xie Guo-Feng  ,   低维材料及其应用技术教育部重点实验室,湘潭大学材料与光电物理学院,湘潭  411105
Published: December 2020

Variable charge molecular dynamics simulations of SiC intergranular glassy films have been performed based on the iterative fluctuation charge model. The atomistic structures of different configurations of the intergranular films are simulated. Charge transfer between the films and their neighboring crystals is observed and the equilibrium film thickness is found to be dependent on the charge transfer. Our results provide a direct proof for the existence of space charges and show that electrostatic interaction contributes to the equilibrium thickness of the intergranular films.
Electronic structure and bonding mechanism of La-Ir-Si: A first-principles study
Authors: Liu Jun-Min  , Sun Li-Zhong  , Chen Yuan-Ping  , Zhang Kai-Wang  , Yuan Hui-Qiu  , Zhong Jian-Xin  ,   (1)湘潭大学量子工程与微纳能源技术湖南省高校重点实验室,湘潭  411105；湘潭大学材料与光电物理学院,湘潭  411105; (2)浙江大学物理系,杭州  310027
Published: December 2020

Using first-principles method, we studied the electronic structure and the bonding mechanism of La-Ir-Si materials. The results of the band structure and the density of the states indicated that the superconducting property of the La-Ir-Si system is determined by the p-d coupling strength between the transition element Ir-d and Si-p states of the material. In order to quantitatively describe the p-d coupling strength, we calculated the charge transfer during the bond process of the materials using the atom-in-molecule method. The results revealed that the superconducting transition temperature TC is linerly proportional to the atomic basin charges of Ir.
An effective method for suppressing the mode competition in a rectangular cavity loaded with photonic crystals
Authors: Liu Yang  , Gong Hua-Rong  , Wei Yan-Yu  , Gong Yu-Bin  , Wang Wen-Xiang  , Liao Fu-Jiang  ,   电子科技大学物理电子学院大功率微波电真空器件技术重点实验室,成都  610054
Published: December 2020

In this paper, the photonic crystal loaded rectangular resonant cavity is studied. Because the conventional way cannat ensure single-mode operation in the cavity when operated with higher-order modes, characteristic impedance method and perturbation method are employed to change the structure of the conventional photonic crystals cavity. The improved cavity that can work with a single higher-order mode is realized. On this basis, the conventional photonic crystal shielded cavity, which can work with a mode of TM530, is reformed by the new method. The new structures are analyzed by using analytical methods and HFSS. The physical reasons of these methods solving the problem of mode competition are also analyzed. The investigation reveals that the method can effectively suppress mode competition and realize single-modc operation in the cavity when operated with higher-order modes.
First-principles study on field emission properties of carbon nanocone
Authors: Wang Liu-Ding  , Chen Guo-Dong  , Zhang Jiao-Qiang  , Yang Min  , Wang Yi-Jun  , An Bo  ,   (1)西北工业大学应用化学系，西安  710129; (2)西北工业大学应用物理系，西安  710129
Published: December 2020

The first-principles calculation was performed to study the electron field emission properties of carbon nanocones （CNC） with different cone angles and geometrical structures. The results show that with the increase of the applied electric field （Eadd）, the electronic structure of CNC changes significantly, the density of states （DOS） shifts towards to low energy position. Especially, DOS at Ef increases and the pseudogap decreases respectively, and a majority of electrons congregate at the close end. The investigation of DOS, HOMO/LUMO and Mulliken population analysis indicates that CNC3 and CNC4 are very suited for electron field emission.
Effects of absorption layer parameters and hetero-interface charge on photoresponse of 12.5 μm long-wavelength HgCdTe photodiode
Authors: Hu Wei-Da  , Yin Fei  , Ye Zhen-Hua  , Quan Zhi-Jue  , Hu Xiao-Ning  , Li Zhi-Feng  , Chen Xiao-Shuang  , Lu Wei  ,   中国科学院上海技术物理研究所，红外物理国家重点实验室，上海  200083
Published: December 2020

The effects of absorption layer parameters and hetero-interface charge on photoresponse of long-wavelength HgCdTe photodiode have been studied. The correlations between thickness of absorption layer and absorption length and diffusion length are investigated. An empirical formula is proposed to estimate the optimal thickness of absorption layer. Our theoretical investigations indicate that, when the wavelength of incident light is longer than the cut-off wavelength, the photoresponse monotonically increases with the increase of absorption layer thickness, and saturates subsequently. The wavelength of the maximal photoresponse increases with the increase of absorption layer thickness, and tends to shift toward long wavelength region. The optimal absorption layer thickness increases with increasing minority carrier life time and wavelength of incident light. It is found that the positive interface charge can induce a p-n junction at the substrate interface and significantly reduce the photoresponse. By using the metal-oxide-semiconductor diode model, possible physics mechanisms are investigated, and an approach is proposed to reduce the effects of hetero-interface charge on the photoresponse.
Spin-polarized transport in quantum waveguide systems with attached stubs
Authors: Xiao Xian-Bo  , Li Xiao-Mao  , Chen Yu-Guang  ,   (1)江西农业大学理学院,南昌  330045; (2)同济大学物理系,上海  200092; (3)同济大学物理系,上海  200092；江西农业大学理学院,南昌  330045
Published: December 2020

We theoretically studied the spin-polarized electron transport properties of quantum waveguide systems with attached stubs in the presence of Rashba spin-orbit coupling （SOC） by the lattice Green function approach. It is shown that the structure-induced Fano resonance and SOC-induced Fano resonance exist in the charge conductance in consequence of the bound states interfering with the conductance states. At the same time, the Fano resonance and antiresonance structures are also found in the spin polarization. In addition, due to the effect of quantum interference and backscattering caused by abrupt change of quantum wire width, a series of resonant peaks and dips appear in the charge conductance and spin conductance. However, all these effects are suppressed and quantization plateau is recovered in the charge conductance and spin conductance when applying a magnetic field to the system. The underlying physics is that the effect of the magnetic field is equivalent to the enhancement of the lateral confining potential, which reduces the intersubband mixing.
Band structure of strained Si1-xGex
Authors: Song Jian-Jun  , Zhang He-Ming  , Hu Hui-Yong  , Xuan Rong-Xi  , Dai Xian-Ying  ,   西安电子科技大学微电子学院,宽禁带半导体材料与器件重点实验室,西安  710071
Published: December 2020

There has been a lot of interest in the Si based strained technology lately, especially the modification of band structures which provides a theoretical basis for the design of the high-speed and high-performance devices and circuits. The band structure models of strained Si1-xGex on （001）,（101）,（111） relaxed Si are set up using K.P perturbation method coupled with deformation potential theory. Ge fraction （x） dependence of the conduction band　（CB） and the valence band　（VB） edge levels, CB and VB splitting energy and the indirect bandgap were obtained. The quantitative data from the models can supply valuable references to the design of devices.
Effects of applied magnetic field on microstructure and magnetic properties of template-based Co nanowire arrays
Authors: Liu Wen-Bang  , Meng Wei-Min  , Lou Yuan-Fu  , Liu　Xi  , Zhang Lu-Ran  , Zheng Xin-Ｑi  , Wei Fu-Lin  ,   兰州大学磁学与磁性材料教育部重点实验室,兰州大学磁性材料研究所,兰州  730000
Published: December 2020

Arrays of Co nanowires were fabricated by ac electrochemical deposition of metal into high order anodic alumina templates prepared through two-step oxidation method. The effects of applied magnetic field and the pH value of the electrolyte on growth of nanowires were investigated. Arrays of Co nanowires of hcp structure were deposited in the electrolyte whose pH values are 6.0 and 6.5 without magnetic field, then 0.3 T magnetic field was applied along the long axis of nanowires. The experimental results show that external magnetic field and adjustment of pH value of the electrolyte impel the easy magnetization axis of the hcp Co grain to grow along length direction of nanowires. The Co nanowire arrays show higher perpendicular anisotropy, larger coercivity and high M/Ms because the superposition of the crystal anisotropy of hcp Co grains and shape anisotropy of nanowire along length direction.
Magnetic properties of ultrathin (4?)Fe film studied by polarized neutron reflectometry
Authors: Li Tian-Fu  , Chen Dong-Feng  , Wang Hong-Li  , Sun Kai  , Liu Yun-Tao  ,   (1)中国原子能科学研究院,北京  102413; (2)中国原子能科学研究院,北京  102413；德国柏林HMI研究所,柏林  D-14109
Published: December 2020

Ultrathin Fe film 200  V/4  Fe/900  V/MgO（100） has been prepared by molecular beam epitaxy （MBE）. The structure parameters, such as the surface and interface roughness and the thickness of each layer, were obtained by X-ray and neutron reflectivity measurement. The magnetic properties of the thin Fe layer were investigated by polarized neutron reflectometry at different temperature. The result shows that the magnetic moment of an Fe atom is about 1.0±0.1　μB at room temperature and increases to 1.5±0.1 μB at 10　K. The Curie temperature of the thin Fe film is estimated to be 310±30K.
Current-induced magnetization switching in spin valves
Authors: Bao Jin  , Xu Xiao-Guang  , Jiang Yong  ,   新金属材料国家重点实验室,材料科学与工程学院,北京科技大学,北京  100083
Published: December 2020

Recently, current-induced magnetization switching （CIMS） behavior in current-perpendicular-to-plane （CPP） exchange-biased spin valve （ESPV） nanopillars has been attracting great attention. In this paper, we experimentally study the CIMS in a special antisymmetric ESPV structure. With the increase of the external magnetic field, the device shows a transition from inverted CIMS to normal CIMS, which is possibly due to the different magnetic configuration in the antisymmetric ESPV.
Density prediction of selective laser sintering parts based on support vector regression
Authors: Cai Cong-Zhong  , Pei Jun-Fang  , Wen Yu-Feng  , Zhu Xing-Jian  , Xiao Ting-Ting  ,   重庆大学应用物理系,重庆  400044
Published: December 2020

The support vector regression （SVR） approach combined with particle swarm optimization for parameter optimization, is proposed to establish a model for estimating the density of selective laser sintering parts under processing parameters, including layer thickness, hatch spacing, laser power, scanning speed, ambient temperature, interval time and scanning mode. A comparison between the prediction results and the results from the BP neural networks strongly supports that the internal fitting capacity and prediction accuracy of SVR model are superior to those of BP neural networks under the identical training and test samples; the generation ability of SVR model can be efficiently improved by increasing the number of training samples. The minimum error value is provided by leave-one-out cross validation test of SVR. These results suggest that SVR is an effective and powerful tool for estimating the density of selective laser sintering parts.
Simulation of light coupling enhancement and localization of transmission field via subwavelength metallic gratings
Authors: Bai Wen-Li  , Guo Bao-Shan  , Cai Li-Kang  , Gan Qiao-Qiang  , Song Guo-Feng  ,   (1)美国里海大学电子工程系，伯利恒  18015; (2)中国科学院半导体研究所，北京  100083
Published: December 2020

Surface plasmons（SPs） generated in nano metallic gratings on medium layer can greatly enhance the transmission field through the metallic gratings. The enhancement effect is achieved from λ=500 nm to near-infrared domain. The enhancement rate is about 110% at the wavelength of about 610 nm and about 180% at λ=700　nm and 740 nm where most kinds of thin film solar cells have a high spectral response. These structures should provide a promising way to increase the coupling efficiency of thin film solar cells and optical detectors of different wavelength response.
Optical and scintillation properties of Ce:YAG crystal and transparent ceramics
Authors: Yang Xin-Bo  , Shi Yun  , Li Hong-Jun  , Bi Qun-Yu  , Su Liang-Bi  , Liu Qian  , Pan Yu-Bai  , Xu Jun  ,   (1)中国科学院上海光学精密机械研究所，上海  201800；中国科学院研究生院，北京  100049; (2)中国科学院上海硅酸盐研究所透明光功能无机材料重点实验室，上海  200050; (3)中国科学院上海硅酸盐研究所透明光功能无机材料重点实验室，上海  200050；中国科学院研究生院，北京  100049
Published: December 2020

In this work, Ce:YAG crystal and transparent ceramics were prepared by the temperature gradient technique （TGT） and sintering in vacuum， respectively. The optical and scintillation properties of the as-prepared Ce:YAG crystal and ceramics were investigated and compared. Both crystal and ceramics show typical Ce3+ absorption bands at 230，340 and 460 nm and a 540 nm emission peak. However, the color center absorption bands at 296 and 370 nm with an emission peak at 398 nm were also observed in the TGT crystal. X-ray fluorescence spectra of crystal and ceramics show an emission peak at 520 nm, but another emission peak at 300 nm was found in the crystal which can be attributed to the YAl antisite defects. An average light output of 16800 and 9800 photons/MeV and a single exponential decay with the decay time constants of 61.9 and 62.97 ns were found in the as-prepared Ce:YAG crystal and ceramics. Compared with Ce:YAG ceramics, Ce:YAG crystal shows a higher light yield and faster response.