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A Conservative SAV-RRK Finite Element Method for the Nonlinear Schrodinger Equation

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Advances in Applied Mathematics and Mechanics 2023年第3期15卷 583-601页

作者： jun yang Nianyu Yi School of Mathematics and Computational Science Xiangtan UniversityXiangtanHunan 411105China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan UniversityXiangtanHunan 411105China

*** this paper,we propose,analyze and numerically validate a conservative finite element method for the nonlinear Schrodinger equation.A scalar auxiliary variable(SAV)is introduced to reformulate the nonlinear Schrodinger equation into an equivalent system and to transform the energy into a quadratic *** use the standard continuous finite element method for the spatial discretization,and the relaxation Runge-Kutta method for the time *** mass and energy conservation laws are shown for the semi-discrete finite element scheme,and also preserved for the full-discrete scheme with suitable relaxation coefficient in the relaxation Runge-Kutta *** examples are presented to demonstrate the accuracy of the proposed method,and the conservation of mass and energy in long time simulations.

关键词： Schrodinger equation mass conservation energy conservation finite element method relaxation Runge-Kutta scalar auxiliary variable

High performance of La-doped Y2O3 transparent ceramics

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Journal of Advanced Ceramics 2020年第4期9卷 493-502页

作者： Lei Zhang jun yang Hongyu Yu Wei Pan Shenzhen Institute of Wide-Bandgap Semiconductors and Engineering Research Center of Integrated Circuits for Next-Generation Communications of Ministry of Education School of MicroelectronicsSouthern University of Science and TechnologyShenzhen518055China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Department of General Education Army Engineering University of PLANanjing211101China

As an optical material,Y2O3 transparent ceramics are desirable for application as laser host ***,it is difficult to sinter and dense of Y2O3 hinders the preparation of high-quality optical ceramics via traditional *** this work,we use La2O3 as a sintering aid for fabricating high-transparency Y2O3 ceramics using a vacuum sintering *** is demonstrated that the in-line optical transmittance of 15.0 at%La-doped Y2O3 at a wavelength of 1100 nm achieves a transmittance of 81.2%.A sintering kinetics analysis reveals that a grain-boundary-diffusion-controlled mechanism dominates the faster densification at high La3+*** is also shown that both the mechanical and thermal properties of Y2O3 transparent ceramics are significantly improved upon the increase of La2O3 sintering *** results indicate that a La-doped Y2O3 transparent ceramic is a promising candidate for a laser host material.

关键词： Y2O3 transparent ceramics optical transmittance sintering kinetics mechanical properties thermal properties

Design and analysis of an underwater inductive coupling power transfer system for autonomous underwater vehicle docking applications

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第1期15卷 51-62页

作者： Jian-guang SHI De-jun LI Can-jun yang State Key Laboratory of Fluid Power Transmission and Control

We develop a new kind of underwater inductive coupling power transfer(ICPT)system to evaluate wireless power transfer in autonomous underwater vehicle(AUV)docking *** that determine the performance of the system are systematically analyzed through mathematical methods.A circuit simulation model and a finite element analysis(FEA)simulation model are developed to study the power losses of the system,including copper loss in coils,semiconductor loss in circuits,and eddy current loss in transmission *** characteristics of the power losses can provide guidelines to improve the efficiency of ICPT *** results and simulation results are validated by relevant experiments of the prototype *** output power of the prototype system is up to 45 W and the efficiency is up to *** preliminary results indicate that the efficiency will increase as the transmission power is raised by increasing the input *** the output power reaches 500 W,the efficiency is expected to exceed *** efficiency can be further improved by choosing proper semiconductors and *** analysis methods prove effective in predicting the performance of similar ICPT systems and should be useful in designing new systems.

关键词： Inductive coupling power transfer(ICPT) Autonomous underwater vehicle(AUV) docking Coupling coefficient Resonant capacitance Power transfer efficiency Power loss Eddy current

Controlling continuum wavepacket interference by two-color laser field in over-the-barrier ionization regime

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Frontiers of physics 2016年第1期11卷 105-110页

作者： Sheng-Peng Zhou Yu-jun yang Da-jun Ding Institute of Atomic and Molecular Physics Jilin University Changchun 130012 China

Continuum wavepacket interference is investigated by numerically solving the time-dependent SchrSdinger equation for the interaction of hydrogen atoms with laser fields. The obtained wavepacket evolution indicates that, in the over-the-barrier ionization regime （1016 W/cm2）, the continuum-continuum （CC） interference of ionizing electrons becomes the main process in high- order harmonics generation （HHG）, compared with continuum-bound （CB） transition, as reported by Kohler et al. [Phys. Rev. Lett. 105（20）, 203902 （2010）]. We propose a two-color laser field scheme for controlling the quantum trajectories of ionizing electrons and for extending the CC harmonic energy. As a result, a high energy platform occurs in the HHG spectrum, which entirely originates from the CC harmonics, with a cutoff adjustable by the relative phase of the two-color fields. This provides further understanding of the dynamic feature of atoms and molecules in super intense laser fields and provides an opportunity to image the atomic or molecular potential.

关键词： continuum continuum interference high-order harmonic generation over-the-barrierionization

SYNTHESIS AND CHARACTERIZATION OF BENZOCYCLOBUTEN-4-YL ACRYLATE MONOMER AND ITS RADICAL POLYMERIZATION

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Chinese Journal of Polymer Science 2010年第6期28卷 877-885页

作者： Li-qin Xie jun-xiao yang Fang-hua Zhu Hai-jun yang Cai-lin Liu Lin zhang School of Materials Science and Engineering Southwest University of Science and Technology Mianyang 621010 China Research Center of Laser Fusion China Academy of Engineering Physics Mianyang 621900 China

A benzocyclobuten-4-yl acrylate（1） monomer was prepared by esterification of 4-hydroxybenzocyclobutene with acryloyl *** radical homopolymerization of 1 and copolymerization of 1 with styrene or n-butyl acrylate were carried out to produce linear polymers 2a,2b and *** of these linear polymers under thermal initiation gave corresponding cross-linked polymers 3a,3b and *** ring-opening reaction in the cross-linking process was confirmed by on-line infrared *** scanning calorimetry showed that the glass transition temperatures of linear polymers 2a and 2b were 83.2℃and 68.1℃,*** analysis of the cross-linked polymers showed that they all exhibited good thermal stability.

关键词： Benzocyclobuten-4-yl acrylate Polymerization Cross-linking Thermal stability

Conformists and Contrarians in a Kuramoto Model with Uniformly Distributed Natural Frequencies

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Communications in Theoretical Physics 2013年第6期59卷 684-688页

作者： YUAN Di yang jun-Zhong School of Science Beijing University of Posts and Telecommunications Beijing 100876 China School of Physics and Electrical Engineering Anyang Normal University Anyang 455000 China

A generalization of the Kuramoto model in which oscillators are coupled to the mean field with random signs is investigated in this work. We focus on a situation in which the natural frequencies of oscillators follow a uniform probability density. By numerically simulating the model, we find that the model supports a modulated travelling wave state except for already reported 7r state and travelling wave state in the one with natural frequencies following Lorenztian probability density or a delta function. The dependence of the observed dynamics on the parameters of the model is explored and we find that the onset of synchronization in the model displays a non-monotonic dependence on both positive and negative coupling strength.

关键词： Kuramoto model modulated travelling wave state conformist contrarian

Hierarchical porous carbon derived from animal bone as matric to encapsulated selenium for high performance Li-Se battery

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Rare Metals 2017年第5期36卷 434-441页

作者： Li-Sheng Xie Sheng-Xue Yu Hui-jun yang jun yang Jian-Lan Ni Jiu-Lin Wang Shanghai Electrochemical Energy Devices Research Center Department of Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China College of Environment and Chemistry Engineering Yanshan UniversityQinhuangdao 066004China Shanghai Using Yuan Environmental Engineering Co. LtdShanghai 201801China

Animal bone was employed as raw material to prepare hierarchical porous carbon by KOH activation. Rare metal selenium（Se） was encapsulated into hierarchical porous carbon successfully for the cathode material of Li–Se battery, achieving the transformation of waste into energy,protecting environment and reducing the spread of the disease. Animal bone porous carbon（ABPC） acquires a specific surface area of 1244.7903 m^2·g^-1 and a pore volume of 0.594184 cm^3·g^-1. The composite Se/ABPC with 51 wt%Se was tested as a novel cathode for Li–Se batteries. The results show that Se/ABPC exhibits high specific capacity,good cycling stability and current-rate performance; at 0.1C,the composite Se/ABPC delivers a high reversible capacity of 705 mAh·g^-1 in the second cycle and 591 mAh·g^-1 after 98 cycles. Even at the current density of 2.0C, it can still maintain at a reversible capacity of 485 mAh·g^-1. The excellent electrochemical properties benefit from the high electron conductivity and the carbon with unique hierarchical porous structure. ABPC can be a promising carbon matrix for Li–Se batteries.

关键词： Se/ABPC Animal bones High rate capability Li–Se battery Hierarchical porous structure

Generalized Synchronization in a Drive-Response System

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Communications in Theoretical Physics 2008年第2期49卷 391-395页

作者： yang jun-Zhong ZHANG Mei School of Science Beijing University of Posts and Telecommunications Beijing 100876 China Center for Advanced Study Tsinghua University Beijing 100084 China

The phenomena of GS in a drive-response system have been studied. Several kinds of GS are found： the driver-induced GS, the responser-induced GS, and the intermediate GS. The mechanism generating these types of GS is... 详细信息

关键词： generalized synchronization drive-response system

Relativistic transformation between τ and TCB for Mars missions: Fourier analysis on its accessibility with clock offset

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Research in Astronomy and Astrophysics 2013年第11期13卷 1358-1362页

作者： jun-yang Pan Yi Xie Department of Astronomy Nanjing University Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education

In the context of the fact that Einstein＇s general relativity has become an inevitable part of deep space missions, we will extend previous works on relativistic transformation between the proper time ^- of a clock onboard a spacecraft orbiting Mars and the Barycentric Coordinate Time （TCB） by taking the clock offset into ac- count and investigate its accessibility by Fourier analysis on the residuals after fitting the ^--TCB curve in terms of n-th order polynomials. We find that if the accuracy of a clock can achieve better than ~ 10-5 s or ~ 10-6 s （depending on the type of clock offset） in one year after calibration, the relativistic effects on the difference between 7- and TCB will need to be carefully considered.

关键词： reference systems -- time -- methods: numerical-- space vehicles