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半导体材料中激子扩散动力学研究进展 被引量:1
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作者 王莉 王庆禄 王志刚 《半导体技术》 CAS CSCD 北大核心 2013年第10期729-734,共6页
在半导体量子阱器件中,激子发光占有非常重要的地位。阐述了半导体材料中激子扩散动力学研究进展。首先在介绍半导体量子阱中激子的新奇发光现象——双发光环的基础上,阐明了双环图案形成的物理机制;其次介绍了量子阱中偶极激子扩散的... 在半导体量子阱器件中,激子发光占有非常重要的地位。阐述了半导体材料中激子扩散动力学研究进展。首先在介绍半导体量子阱中激子的新奇发光现象——双发光环的基础上,阐明了双环图案形成的物理机制;其次介绍了量子阱中偶极激子扩散的特点与物理机制,总结了静电陷阱和应力陷阱中的激子非线性扩散动力学的理论与实验研究成果,然后对有机物半导体中激子扩散进行了概述;最后展望了半导体量子阱中激子的玻色-爱因斯坦凝聚在大功率、低功耗的光电子器件、超快逻辑器件和量子计算中的应用前景。 展开更多
关键词 激子 长程扩散 发光环 陷阱 量子阱器件
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YG6C硬质合金与Cr12钢真空钎焊工艺研究
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作者 黄强 陆友富 《机电信息》 2012年第18期111-116,共6页
采用CuMnCo钎料对YG6C硬质合金与Cr12钢真空钎焊进行研究,通过三点弯曲试验、光学显微镜、显微硬度计、SEM和EDS等,分析了钎焊温度和钎焊间隙对钎缝组织及接头性能的影响。
关键词 YG6C硬质合金 CR12钢 真空钎焊 长程扩散 冶金结合
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Super long-range diffusion of carbon during proeutectoid ferrite transformation 被引量:2
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作者 ZHANG Suo-quan JIAO Si-hai +3 位作者 DING Jian-hua WAN Di LIU Zhen-yu WANG Guo-dong 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第3期560-566,共7页
In order to explore the possible diffusion distance of carbon during proeutectoid ferrite transformation, a slow cooling test of low carbon steel was carried out under vacuum of the thermal simulator. The microstructu... In order to explore the possible diffusion distance of carbon during proeutectoid ferrite transformation, a slow cooling test of low carbon steel was carried out under vacuum of the thermal simulator. The microstructure and thermal expansion curve were discussed and the carbon concentration inside the sample was measured. The ferrite layer of about 450 μm thickness was obtained without pearlite on the surface of the sample in the microstructure. The thermal expansion curve shows that the ferrite layer without pearlite is formed during the local phase transformation, which is followed by the global transformation. The carbon concentration in the core of the sample (0.061%) is significantly higher than that of the bulk material (0.054%). All results show that carbon has long-range diffusion from the outer layer to the inner layer of the sample. The transformation is predominantly interface-controlled mode during local transformation, and the interface migration rate is about 2.25 μm/s. 展开更多
关键词 low carbon steel local transformation super long-rang diffusion interface-controlled mode
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New Exact Solutions to Dispersive Long-Wave Equations in (2+1)-Dimensional Space 被引量:2
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作者 TIAN Ying-Hui CHEN Han-Lin LIU Xi-Qiang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2期207-210,共4页
New exact solutions expressed by the Jacobi elliptic functions are obtained to the (2+1)-dimensional dispersive long-wave equations by using the modified F-expansion method. In the limit case, new solitary wave sol... New exact solutions expressed by the Jacobi elliptic functions are obtained to the (2+1)-dimensional dispersive long-wave equations by using the modified F-expansion method. In the limit case, new solitary wave solutions and triangular periodic wave solutions are obtained as well. 展开更多
关键词 dispersive long-wave equations modified F-expansion method exact solutions Jacobi elliptic functions
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New Exact Travelling Wave Solutions to Hirota Equation and (1+1)-Dimensional Dispersive Long Wave Equation
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作者 WANGQi CHENYong +1 位作者 LIBiao ZHANGHong-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第6期821-828,共8页
Based on the computerized symbolic Maple, we study two important nonlinear evolution equations, i.e., the Hirota equation and the (1+1)-dimensional dispersive long wave equation by use of a direct and unified algebrai... Based on the computerized symbolic Maple, we study two important nonlinear evolution equations, i.e., the Hirota equation and the (1+1)-dimensional dispersive long wave equation by use of a direct and unified algebraic method named the general projective Riccati equation method to find more exact solutions to nonlinear differential equations. The method is more powerful than most of the existing tanh method. New and more general form solutions are obtained. The properties of the new formal solitary wave solutions are shown by some figures. 展开更多
关键词 projective Riccati equation method (1+1)-dimensional dispersive long wave equation Hirota equation
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A Generalized Extended F-Expansion Method and Its Application in (2+1)-Dimensional Dispersive Long Wave Equation 被引量:1
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作者 HUANG Wen-Hua 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第4X期580-586,共7页
A new generalized extended F-expansion method is presented for finding periodic wave solutions of nonlinear evolution equations in mathematical physics. As an application of this method, we study the (2+1)-dimensio... A new generalized extended F-expansion method is presented for finding periodic wave solutions of nonlinear evolution equations in mathematical physics. As an application of this method, we study the (2+1)-dimensional dispersive long wave equation. With the aid of computerized symbolic computation, a number of doubly periodic wave solutions expressed by various Jacobi elliptic functions are obtained. In the limit cases, the solitary wave solutions are derived as well. 展开更多
关键词 (2+1)-dimensional dispersive long wave equation extended F-expansion Jacobi elliptic function periodic wave solution
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Further Extended Jacobi Elliptic Function Rational Expansion Method and New Families of Jacobi Elliptic Function Solutions to (2+1)-Dimensional Dispersive Long Wave Equation
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作者 ZHANG Yuan-Yuan WANG Qi ZHANG Hong-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2期199-206,共8页
In this paper, a further extended Jacobi elliptic function rationM expansion method is proposed for constructing new forms of exact solutions to nonlinear partial differential equations by making a more general transf... In this paper, a further extended Jacobi elliptic function rationM expansion method is proposed for constructing new forms of exact solutions to nonlinear partial differential equations by making a more general transformation. For illustration, we apply the method to (2+1)-dimensionM dispersive long wave equation and successfully obtain many new doubly periodic solutions. When the modulus m→1, these sohitions degenerate as soliton solutions. The method can be also applied to other nonlinear partial differential equations. 展开更多
关键词 doubly periodic solution soliton solution (2+1)-dimensional dispersive long wave equation
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Epitaxial n- and p-type Emitters for High Efficiency Solar Cell Concepts
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作者 Thomas Rachow Friedemann Heinz Bemd Steinhauser Stefan Janz Stefan Reber 《Journal of Energy and Power Engineering》 2014年第8期1371-1377,共7页
Reducing the module prices by increasing the efficiency of solar cells is one of the major challenges in today's photovoltaic research. The emitter formation by epitaxial growth offers a cost-efficient and faster alt... Reducing the module prices by increasing the efficiency of solar cells is one of the major challenges in today's photovoltaic research. The emitter formation by epitaxial growth offers a cost-efficient and faster alternative to the standard furnace diffusion process. The efficiency potential of epitaxial emitters 〉 22% has already been proven using a single wafer, low pressure, chemical vapour deposition tool. The purpose of this work is to show the potential of epitaxially grown emitters by APCVD (atmospheric pressure chemical vapour deposition) compared to diffused emitters. The APCVD formation of epitaxial emitters at 1,050 ~C can be realised as high throughput inline process and only takes 1-2 min, whereas the diffusion process using POCI3 takes up to 60 min. Simulations show an increase in voltage of AVoc = +10 mV and a reduction in saturation current ,1o of 30% for the epitaxial emitter. The lifetime experiments of solar cells with epitaxial emitter exhibit a diffusion length Leff〉 750μm and an emitter saturation current of Joe 〈 50 fA/cm2 on a planar 10 Ω2cm p-type FZ wafer. Another important aim of this work is to evaluate the limitations of epitaxial emitters due to high thermal budget, interface recombination and the change of reflective properties on textured wafers due to the deposition process. Solar cell efficiencies up to 18.4% on p-type and 20.0% on n-type wafers presented in this paper underline that the emitter epitaxy by APCVD is a competitive process for the emitter formation. 展开更多
关键词 Solar cells pn-junction emitter formation silicon deposition EPITAXY APCVD
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Exponential mean-square stability of the improved split-step theta methods for non-autonomous stochastic differential equations 被引量:3
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作者 YUE Chao 《Science China Mathematics》 SCIE CSCD 2017年第4期735-744,共10页
We consider the mean-square stability of the so-called improved split-step theta method for stochastic differential equations. First, we study the mean-square stability of the method for linear test equations with rea... We consider the mean-square stability of the so-called improved split-step theta method for stochastic differential equations. First, we study the mean-square stability of the method for linear test equations with real parameters. When 0 ≥ 3/2, the improved split-step theta methods can reproduce the mean-square stability of the linear test equations for any step sizes h 〉 0. Then, under a coupled condition on the drift and diffusion coefficients, we consider exponential mean-square stability of the method for nonlinear non-autonomous stochastic differential equations. Finally, the obtained results are supported by numerical experiments. 展开更多
关键词 stochastic differential equations mean-square stability improved split-step theta methods expo-nential mean-square stability
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