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Optical Nutation Effect in the Three-Level System Driven by a Coherent Microwave Field

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Chinese Physics Letters 1997年第8期14卷 589-592页

作者： cao Zhuo-liang GUO guang-can Department of Physics Anhui UniversityHefei 230039 Department of Physics University of Science and Technology of ChinaHefei 230026

In this paper,a coherent transient effect-optical nutation in Bloch form is studied semiclassically in the three-level atomic system driven by a coherent microwave *** amplitude of the optical nutation signal field is *** is found that the signal field,related to the microwave,is the overlap of two slow oscillations instead of one.

关键词： field. microwave coherent

Study on tungsten sintering temperature field based on electromagnetic simulation and computational fluid dynamics

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Tungsten 2024年第2期6卷 355-366页

作者： Lu-yan Wang Yue-guang Yu Jian-Xin Dong Kai-Ping Du Shan-Yu Liu cao-Bing Li University of Science and Technology Beijing Beijing 100083China BGRIMM Technology Group Beijing 100160China China Iron&Steel Research Institute Group Beijing 100081China

In order to study the influence of various sintering variables more intuitively and clearly,electromagnetic field analysis and computational fl uid dynamics are used to analyze the infl uence of gas flow,heating power and other process parameters on the temperature range of medium-frequency sintering in this *** results indicate that the uniformity of temperature fi eld is determined by the gas flow rate and heating *** the heating power is 50 kW,the stable temperature drops about 10 K for every 1 m^(3)·h^(−1)increase of hydrogen *** peak value of the maximum temperature diff erence on the tungsten rods gradually increases with the increase of the hydrogen flow rate,and it appears slightly *** temperature distribution of tungsten rods in furnace is similar with diff erent hydrogen flow *** the same time,the closer to the furnace wall,the higher the temperature of the tungsten *** temperature diff erence between tungsten rods mainly occurred within 1 h after the beginning of *** the heating power can improve the stable temperature,but has little eff ect on the heating *** heating power can increase the peak value of the maximum temperature diff erence on the tungsten rods,but has little eff ect on the occurrence time of the peak value of the maximum temperature diff erence on the tungsten *** the heating power will increase the temperature diff erence of a single tungsten rod,but the temperature diff erence of a single tungsten rod never exceeds 65 *** study can be used to guide the process optimization *** with numerical simulation calculation,the sintering parameters with low energy consumption and high temperature uniformity can be quickly and eff ectively found,thus improving the microstructure and properties of sintered tungsten products.

关键词： Tungsten products Sintering Hydrogen flow rate Heating power

Recovery of the Solitons Using a Lattice Boltzmann Model

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Chinese Physics Letters 1999年第2期16卷 109-110页

作者： yan guang-wu SONG Min Laboratory for Nonlinear Mechanics of Continuous Media Institute of MechanicsChinese Academy of SciencesBeijing 100080 Department of Mathematics Jilin UniversityChangchun 130023 Division of Foundation Jilin Province Architect CollegeChangchun 130053

We formulate a lattice Boltzmann model which simulates Korteweg-de Vries equation by using a method of higher moments of lattice Boltzmann *** a series of lattice Boltzmann equations in different time scales and the conservation law in time scale t0,we obtain equilibrium distribution *** numerical examples show that the method can be used to simulate soliton.

关键词： equation. function. lattice

Control design of 60kW PEMFC generation system for residential applications

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第9期14卷 679-685页

作者： Ying-ying ZHANG Ying ZHANG Xi LI guang-yi cao Shandong Provincial Key Laboratory of Ocean Environment Monitoring Technology Institute of Oceanographic Instrumentation Shandong Academy of Sciences Control Science and Engineering Department Key Laboratory of the Ministry of Education for Image Processing and Intelligent Control Huazhong University of Science and Technology Fuel Cell Institute Department of Automation Shanghai Jiao Tong University

This paper presented a control design methodology for a proton exchange membrane fuel cell (PEMFC) generation system for residential applications. The dynamic behavior of the generation system is complex in such applications. A comprehensive control design is very important for achieving a steady system operation and efficiency. The control strategy for a 60 kW generation system was proposed and tested based on the system dynamic model. A two-variable single neuron proportional-integral (PI) decoupling controller was developed for anode pressure and humidity by adjusting the hydrogen flow and water injection. A similar controller was developed for cathode pressure and humidity by adjusting the exhaust flow and water injection. The desired oxygen excess ratio was kept by a feedback controller based on the load current. An optimal seeking controller was used to trace the unique optimal power point. Two negative feedback controllers were used to provide AC power and a suitable voltage for residential loads by a power conditioning unit. Control simulation tests showed that 60 kW PEMFC generation system responded well for computer-simulated step changes in the load power demand. This control methodology for a 60 kW PEMFC generation system would be a competitive solution for system level designs such as parameter design, performance analysis, and online optimization.

关键词： Proton exchange membrane fuel cell (PEMFC) Generation system Control strategy decoupling control Optimalseeking control

A Lattice Boltzmann Method for the Chemical Clock in the Belousov-Zhabotinskii Reaction

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Chinese Physics Letters 2001年第7期18卷 918-920页

作者： yan guang-Wu YUAN Li LSEC Institute of Computational MathematicsAcademy of Mathematics and System SciencesChinese Academy of SciencesBeijing 100080 Department of Mathematics Jilin UniversityChangchun 130023

A lattice Boltzmann method for the Belousov-Zhabotinskii reaction is proposed to simulate the chemical *** the Chapman-Enskog expansion and multiscale technique,we obtain a series of lattice Boltzmann equations in different timescales,the conservation law in time scale t0 and coefficients of macroscopic equations to find the equilibrium distribution functions.A simple numerical scheme is designed to simulate the diffusion-reaction *** numerical example shows that the proposed method can be used to simulate chemical systems with the chemical clock.

关键词： functions lattice diffusion

Microwave synthesis of Li_2FeSiO_4 cathode materials for lithium-ion batteries

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Chinese Chemical Letters 2009年第8期20卷 1000-1004页

作者： Zhong Dong Peng yan Bing cao Guo Rong Hu Ke Du Xu guang Gao Zheng Wei Xiao School of Metallurgical Science and Engineering Central South University Changsha 410083 China

A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700 ℃ in 12 rain. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction. ？2009 yan Bing cao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Li-ion battery Cathode material Microwave synthesis Li2FeSiO4

On the Structure of Split Leibniz Triple Systems

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Acta Mathematica Sinica,English Series 2015年第10期31卷 1629-1644页

作者： yan cao Liang Yun CHEN School of Mathematics and Statistics Northeast Normal University Department of Basic Education Harbin University of Science and TechnologyRongcheng Campus

We study the structure of arbitrary split Leibniz triple systems with a coherent O-root space. By developing techniques of connections of roots for this kind of triple systems, under certain conditions, in the case of... 详细信息

关键词： Split Leibniz triple system Lie triple system Leibniz algebra system of roots root space

Effect of Mg addition on TiN inclusions in GCr15 bearing steel

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Journal of Iron and Steel Research International 2022年第6期29卷 925-938页

作者： Lei cao Guo-cheng Wang Yuan-you Xiao Rong-guang yang School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina Key Laboratory of Metallurgy Engineering Liaoning Province University of Science and Technology LiaoningAnshan 114051LiaoningChina Steel Rolling Department Shougang Jingtang United Iron and Steel Co.Ltd.Tangshan 063200HebeiChina

Compared with the original GCr15 bearing steel,TiN inclusions are greatly reduced by the effect of Mg addition,and many different types of non-metallic Mg-containing inclusions were observed in Mg-treated GCr15 bearing steel which includes MgO,MgS·MnS,MgO–MgS·MnS,MgAl_(2)O_(4)–MgS·MnS,MgO–TiN,MgS·MnS–TiN,and MgO–MgS·MnS–*** inclusion size distribution based on automatic inclusion analysis software shows that the number of inclusion with the size ranging from 1 to 3μm increases obviously because a large amount of MgO,MgS·MnS,TiN inclusions containing Mg with smaller sizes are massively *** situ observation on the experimental steel by high-temperature confocal laser scanning microscopy confirms that MgO can provide nucleation sites for *** addition,the MgS·MnS and MgO–MgS·MnS inclusions can also provide positions for the nucleation of *** calculations indicate that after Mg addition to liquid steel,a large number of fine MgO inclusions are generated in the liquid steel because of the strong reactivity of Mg and *** the same time,MgS precedes TiN precipitates in the solid–liquid two-phase region;thus,MgO and MgS·MnS can provide sites for TiN *** last,two possible formation pathways for the above various TiN inclusions containing Mg are discussed.

关键词： Mg treatment GCr15 bearing steel TiN inclusion Size distribution In situ observation

Characterization of polyoxometalates by electrospray ionization mass spectrometry

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Science China Chemistry 2015年第7期58卷 1206-1210页

作者： Qiaodi Jia yan Zhang Jie cao Key Laboratory of Cluster Science Ministry of Education of China Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials School of Chemistry Beijing Institute of Technology

The electrospray behaviors of saturated, substituted, and lacunary polyoxometalates （POMs） with classic Keggin and Dawson structures were investigated systematically by electrospray mass spectrometry （ESI-MS）. The anions included Keggin [SiW12O40]4-, [SiW11O39]8-, [SiW10O36]8 , [SiW9O34]10-, Dawson [P2W18O62]6-, [P2W17O61]10-, and metal-substituted Keggin derivatives such as [PW11MnO40]7-, [SiW10V2O40]6-, and [GeWgCu3O37]10-. Common species observed in the mass spectra arose from the protonation or cationization of either intact or dehydrated precursor ions. Compared to saturated and substituted POMs, lacunary POMs exhibited distinguished MS behaviors such as a much higher degree of cationization and dehydration of the bare polyoxoanions present in the mass spectra. In addition, some of these lacunary POMs were found to undergo subtle speciation change in solution. Freshly prepared solutions are suggested for synthetics for which lacunary POMs are starting materials. The advantages of the cation-exchange process which are prior to MS analysis are illustrated by an example.

关键词： saturated substituted and lacunary POMs electrospray ionization mass spectrometry cation-ion exchange process