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带有空穴子模型的石墨烯气凝胶复合相变材料导热系数的分形研究 被引量:2
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作者 田帅奇 方昕 俞自涛 《热科学与技术》 CAS CSCD 北大核心 2016年第6期438-443,共6页
在分形理论的基础上,确定了基于石墨烯气凝胶(graphene aerogel,GA)骨架复合相变材料的分形维数,并基于改进的Sierpinski地毯建立了带有空穴的导热系数预测模型。预测结果表明,对于基于GA骨架的复合相变材料,在所制得的材料孔隙率为0.7... 在分形理论的基础上,确定了基于石墨烯气凝胶(graphene aerogel,GA)骨架复合相变材料的分形维数,并基于改进的Sierpinski地毯建立了带有空穴的导热系数预测模型。预测结果表明,对于基于GA骨架的复合相变材料,在所制得的材料孔隙率为0.7的条件下,无论空穴尺寸如何,均可将导热系数从相变材料本身的0.250 W/(m·K)提升至10.900 W/(m·K),增长幅度达40倍以上。结果显示,复合相变材料的导热系数随着孔隙率的减小而增加,且在低孔隙率下,导热系数随空穴尺寸的减小而增加。 展开更多
关键词 石墨烯气凝胶 有效导热系数 分形模型 空穴子模型
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新型空穴轴承滚子结构的研究 被引量:4
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作者 葛宰林 魏延刚 张秀娟 《大连铁道学院学报》 1999年第4期30-32,共3页
经理论计算和生产工艺分析,提出新型轴承滚子结构-空穴滚子来代替修形滚子,可以提高滚子轴承的接触疲劳寿命,降低生产成本.
关键词 滚动轴承 空穴 接触疲劳寿命 成本 结构特点 加工工艺
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铜氧面电阻率-温度线性依赖与空穴-声子散射 被引量:2
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作者 毛善成 《沈阳大学学报(自然科学版)》 CAS 2016年第1期1-5,共5页
在BCS理论框架中,推导出高温铜氧化物材料中电子或空穴对间的电声作用强度T与电子费米速度成正比,与相互作用距离的平方根成反比关系,代入索末菲量子自由电子气模型的电阻率公式,计算出高温超导铜氧化物材料正常态电阻率ρab对温度成线... 在BCS理论框架中,推导出高温铜氧化物材料中电子或空穴对间的电声作用强度T与电子费米速度成正比,与相互作用距离的平方根成反比关系,代入索末菲量子自由电子气模型的电阻率公式,计算出高温超导铜氧化物材料正常态电阻率ρab对温度成线性依赖的比例系数β≈0.4×10-6(Ω·cm·K-1),与经验结果较为一致.并用空穴-声子散射机制解释了空穴型高温超导铜氧化物正常态的电阻率随温度的线性依赖行为. 展开更多
关键词 铜氧化物正常态 高温超导体 反常电阻率 空穴-声散射 高温超导机理 状态方程 临界热动量
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客车滚动轴承空穴滚子结构的初步探讨
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作者 葛宰林 魏延刚 《机车车辆工艺》 北大核心 2000年第1期14-14,21,共2页
通过理论计算和生产工艺分析 ,提出以新型的轴承空穴滚子代替母线修形滚子 ,可以提高滚子轴承的接触疲劳寿命 。
关键词 滚动轴承 空穴 疲劳强度 铁路车辆 客车
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弱电场下电子极化子与空穴极化子的散射
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作者 李海宏 李冬梅 +1 位作者 刘文 钱娜娜 《鲁东大学学报(自然科学版)》 2008年第3期233-235,共3页
基于紧束缚的Su-Schrieffer-Heeger(SSH)模型,利用非绝热的动力学方法,研究了弱电场下基态非简并聚合物中电子极化子和空穴极化子的散射.研究发现,体系最终形成一个中性激子态,由于电场力与电声耦合之间的竞争,形成的激子呈现了一个正... 基于紧束缚的Su-Schrieffer-Heeger(SSH)模型,利用非绝热的动力学方法,研究了弱电场下基态非简并聚合物中电子极化子和空穴极化子的散射.研究发现,体系最终形成一个中性激子态,由于电场力与电声耦合之间的竞争,形成的激子呈现了一个正反极化振荡的现象,体系最终达到一个动态的平衡. 展开更多
关键词 极化 空穴极化 有机共轭聚合物 非绝热动力学
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应变层超晶格GaN-AlN的电子结构 被引量:1
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作者 何国敏 王仁智 郑永梅 《固体电子学研究与进展》 CAS CSCD 北大核心 1999年第1期13-19,共7页
采用有效质量理论6带模型,计算了应变层超晶格GaNAlN(001)的电子结构,具体计算不同应变状态的价带子能带色散曲线、光吸收曲线。分析了应变状态以及重轻空穴和自旋轨道分裂带相互作用对子带结构的影响。
关键词 有效质量理论 空穴子 应变层超晶格
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基态简并聚合物中极化子对的碰撞研究 被引量:8
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作者 张永强 李宏 +1 位作者 程杰 李海宏 《原子与分子物理学报》 CAS CSCD 北大核心 2008年第1期161-164,共4页
基于紧束缚的Su-Schrieffer-Heeger(SSH)模型,利用非绝热的动力学方法,研究了基态简并聚合物中空穴极化子和电子极化子的碰撞过程.研究发现,弱电场下两个极化子碰撞分开再相遇形成孤子对,中等强度电场下它们碰撞分开后成为两个准粒子,... 基于紧束缚的Su-Schrieffer-Heeger(SSH)模型,利用非绝热的动力学方法,研究了基态简并聚合物中空穴极化子和电子极化子的碰撞过程.研究发现,弱电场下两个极化子碰撞分开再相遇形成孤子对,中等强度电场下它们碰撞分开后成为两个准粒子,强电场下空穴极化子和电子极化子碰撞后直接解离. 展开更多
关键词 空穴极化和电极化 有机共轭聚合物 非绝热动力学
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分裂的电子
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作者 尤文龙 周丽萍 高雷 《大学物理》 北大核心 2016年第3期1-4,29,共5页
电子是组成世界万物的一种基本粒子.其电荷及自旋自由度在电子处于游离状态时牢不可分.但在某些低维强关联体系中,电子与其他粒子的相互作用会导致两种不同准粒子的出现.其中一种具有非零的正电荷,但自旋自由度为零,称为空穴子.另外一... 电子是组成世界万物的一种基本粒子.其电荷及自旋自由度在电子处于游离状态时牢不可分.但在某些低维强关联体系中,电子与其他粒子的相互作用会导致两种不同准粒子的出现.其中一种具有非零的正电荷,但自旋自由度为零,称为空穴子.另外一种准粒子具有正好相反的性质,即其电荷为零,然而自旋等于电子的自旋,被称为自旋子.这种现象被形象地称为电子的电荷-自旋分离,并被用来解释高温超导电性.最近,空穴子和自旋子的存在进一步得到了实验的证实.此外实验中还观察到另外一种准粒子,它只携带了电子绕核运动的属性,被称为轨道子.在本文中,我们将结合实验,对于这些有趣的现象做一介绍. 展开更多
关键词 低维强关联电体系 准粒 自旋 空穴子 轨道
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Electronic structure and ultraviolet spectra of p-C_(6)H_(4)-C_(20)
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作者 CHEN Xin 《原子与分子物理学报》 CAS 北大核心 2025年第3期21-28,共8页
Geometry optimization of p-C_(6)H_(4)-connected cyclo[20]carbon(p-C_(6)H_(4)-C_(20))was carried out at M062X/6-311G(d,p)level,three kinds of bond orders(Mayer,Laplacian,and Wiberg),electron-hole distributions,localize... Geometry optimization of p-C_(6)H_(4)-connected cyclo[20]carbon(p-C_(6)H_(4)-C_(20))was carried out at M062X/6-311G(d,p)level,three kinds of bond orders(Mayer,Laplacian,and Wiberg),electron-hole distributions,localized orbital locators(LOL),and infrared(IR)spectrum were also performed at the same level.Based on TD-DFT M062X/6-311G(d,p)method,the first 20 excited states and ultraviolet(UV)spectra of p-C_(6)H_(4)-C_(20) were calculated.Calculation results of π-electron delocalization analyses prove thatπ-electron delocalization of p-C_(6)H_(4)-C_(20) is more likely to occur on shorter C-C bonds rather than longer C-C bonds,and inside/outside of the ring plane rather than above/below the ring plane.Two absorption peaks of p-C_(6)H_(4)-C_(20) locate at about 319 nm and 236 nm,respectively. 展开更多
关键词 p-C_(6)H_(4)-C_(20) Bone orders UV spectrum Electron-hole analyses π-electron delocalization analyses
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非简并基态和简并基态聚合物中极化子对的碰撞
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作者 李海宏 郭海波 《济宁学院学报》 2011年第3期43-45,共3页
基于紧束缚的Su-Schrieffer-Heeger(SSH)模型,利用非绝热的动力学方法,研究了非简并基态和简并基态聚合物中电子极化子与空穴极化子的碰撞过程.研究发现,两极化子并不直接复合形成一个整体,而是在电场的作用下碰撞、分开再相遇形成一个... 基于紧束缚的Su-Schrieffer-Heeger(SSH)模型,利用非绝热的动力学方法,研究了非简并基态和简并基态聚合物中电子极化子与空穴极化子的碰撞过程.研究发现,两极化子并不直接复合形成一个整体,而是在电场的作用下碰撞、分开再相遇形成一个整体,在非简并基态聚合物中这个整体是极化子激子,而简并基态聚合物中是孤子对. 展开更多
关键词 极化空穴极化 有机共轭聚合物 非绝热动力学
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电场下GaAs/G_(a1-x)Al_xA_s量子阱中的激子
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作者 唐道华 《零陵学院学报》 1989年第3期18-26,共9页
本文利用有限势垒(左、右垒高不等)模型,研究了电场对GaAs/Ga<sub>1-x</sub>A1xAs量阱中各子带所对应的激子之影响.采用级数展法开求得于带所对应的电子——空穴重叠函数.通过变分计算得到激子结合能.对阱宽为105(?)的G... 本文利用有限势垒(左、右垒高不等)模型,研究了电场对GaAs/Ga<sub>1-x</sub>A1xAs量阱中各子带所对应的激子之影响.采用级数展法开求得于带所对应的电子——空穴重叠函数.通过变分计算得到激子结合能.对阱宽为105(?)的GaAs/Ga<sub>0.66</sub>A1<sub>0.34</sub>As量子阱,电场由0至1.2×10<sup>5</sup>V/cm,我们计算了(电子和空穴的)子带对应的激子之结合能.基于上述计算结果,所得激子峰的能移与实验测量符合得较好,体现出有限势阱模型比无限势阱模型好得多. 展开更多
关键词 结合能 电场变化 空穴子 空穴 GAAS 重叠函数 有效质量
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长程电子关联对有限长聚乙炔链中极化子态的影响
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作者 张渊 赵铧 +1 位作者 刘中旺 沈颖 《原子与分子物理学报》 CAS CSCD 北大核心 2012年第3期544-548,共5页
本文采用扩展Hubbard模型,加上长程关联哈密顿量,在自然边界条件下用自洽场方法研究了有限长反式聚乙炔链中极化子的问题.计算了长程电子关联对极化子的影响并计算了极化子的长程关联能.计算发现长程电子关联使极化子的位形变宽变浅(局... 本文采用扩展Hubbard模型,加上长程关联哈密顿量,在自然边界条件下用自洽场方法研究了有限长反式聚乙炔链中极化子的问题.计算了长程电子关联对极化子的影响并计算了极化子的长程关联能.计算发现长程电子关联使极化子的位形变宽变浅(局域性减弱),在极化子区域,长程电子关联能比平均长程电子关联能要大.当链长增加到100格点以上时,电子极化子和空穴极化子的平均关联能趋于-0.1663eV,而在极化子区域,电子极化子和空穴极化子的平均关联能趋于-0.1868 eV. 展开更多
关键词 长程电关联能 长程关联哈密顿量 极化 空穴极化
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Mechanism of Reverse Snapback on I-V Characteristics of Power SITHs with Buried Gate Structure 被引量:1
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作者 王永顺 李海蓉 +1 位作者 吴蓉 李思渊 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第3期461-466,共6页
The reverse snapback phenomena (RSP) on I-V characteristics of static induction thyristors (SITH) are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to th... The reverse snapback phenomena (RSP) on I-V characteristics of static induction thyristors (SITH) are physically researched. The I-V curves of the power SITH exhibit reverse snapback phenomena, and even turn to the conducting-state,when the anode voltage in the forward blocking-state is increased to a critical value. The RSP I-V characteristics of the power SITH are analyzed in terms of operating mechanism, double carrier injection effect, space charge effect, electron-hole plasma in the channel, and the variation in carrier lifetime. The reverse snapback mechanism is theoretically pro- posed and the mathematical expressions to calculate the voltage and current values at the snapback point are presented. The computing results are compared with the experiment values. 展开更多
关键词 power static induction thyristor reverse snapback electron-hole plasma LIFETIME injection level
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Synthesis,characterization and photocatalytic performance of rod-shaped Pt/PbWO_4 composite microcrystals 被引量:6
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作者 余长林 白羽 +3 位作者 何洪波 范文宏 朱丽华 周晚琴 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第12期2178-2185,共8页
Rod-shaped PbW O4 microcrystals of length 1 μm were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles(NPs) of different contents(0.5 wt%,1 wt% and 2 wt%) were subsequently deposited ... Rod-shaped PbW O4 microcrystals of length 1 μm were fabricated by a hydrothermal route and subsequent calcination. Pt nanoparticles(NPs) of different contents(0.5 wt%,1 wt% and 2 wt%) were subsequently deposited on the PbW O4 microcrystals,producing robust Pt/PbW O4 composite microcrystals. The PbW O4 microcrystals and Pt/PbW O4 photocatalysts were characterized by X-ray diffraction,N2 sorption measurements,scanning electron microscopy,transmission electron microscopy,and X-ray photoelectron,photoluminescence,Fourier-transform infrared,and ultraviolet-visible diffuse reflectance spectroscopies. The photocatalytic performances of the catalysts were evaluated by the consecutive photocatalytic degradation of acid orange II dye. The Pt/PbW O4 composite microcrystals exhibited high photocatalytic activity and stability. The deposition of Pt NPs produced surface plasmon resonance(SPR),which induced a large visible light absorption. A Pt NP content of 1-2 wt% resulted in an ~2 times increase in photocatalytic activity,compared with the activity of Pt/PbW O4. The crystal structure and high crystallinity of PbW O4 resulted in its favorable photocatalytic property,and the SPR effect of the Pt NPs promoted visible light harvesting. The Pt NPs also enhanced the separation of photo-generated electrons and holes,which further promoted the photocatalytic reaction. 展开更多
关键词 Rod-shaped Lead tungstate microcrystals Platium nanoparticles Photocatalytic activity Photocatalytic stability Surface plasma Electron-hole separation
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Bipolar Theory of MOS Field-Effect Transistors and Experiments
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作者 薩支唐 揭斌斌 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第10期1497-1502,共6页
The bipolar theory of field-effect transistor is introduced to replace the 55-year-old classic unipolar theory invented by Shockley in 1952 in order to account for the characteristics observed in recent double-gate na... The bipolar theory of field-effect transistor is introduced to replace the 55-year-old classic unipolar theory invented by Shockley in 1952 in order to account for the characteristics observed in recent double-gate nanometer silicon MOS field-effect transistors. Two electron and two hole surface channels are simultaneously present in all channel current ranges. Output and transfer characteristics are computed over practical base and gate oxide thicknesses. The bipolar theory corroborates well with experimental data reported recently for FinFETs with metal/silicon and p/n junction source/drain contacts. Single-device realization of CMOS inverter and SRAM memory circuit functions are recognized. 展开更多
关键词 unipolar FET theory bipolar FET theory simultaneous hole and electron surface channels volume channel DOUBLE-GATE pure-base
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The Bipolar Field-Effect Transistor:Ⅰ.Electrochemical Current Theory(Two-MOS-Gates on Pure-Base)
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作者 薩支唐 揭斌斌 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第11期1661-1673,共13页
This paper describes the bipolar field-effect transistor (BiFET) and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis ... This paper describes the bipolar field-effect transistor (BiFET) and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis employs the parametric surface-electric-potential and the electrochemical (quasi-Fermi) potential-gradient driving force to compute the current. Output and transfer D. C. current and conductance versus voltage are presented over practi- cal ranges of terminal D. C. voltages and device parameters. Electron and hole surface channel currents are pres- ent simultaneously, a new feature which could provide circuit functions in one physical transistor such as the CMOS inverter and SRAM memory. 展开更多
关键词 bipolar field-effect transistor theory MOS field-effect transistor bipolar junction transistor simul-taneous hole and electron surface channel~ volume channel surface potential
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The Bipolar Field-Effect Transistor: III.Short Channel Electrochemical Current Theory (Two-MOS-Gates on Pure-Base)
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作者 揭斌斌 薩支唐 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第1期1-11,共11页
This paper describes the short channel theory of the bipolar field-effect transistor (BiFET) by partitioning the transistor into two sections,the source and drain sections,each can operate as the electron or hole em... This paper describes the short channel theory of the bipolar field-effect transistor (BiFET) by partitioning the transistor into two sections,the source and drain sections,each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and electron-hole-channel components of the output and transfer currents and conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the long physical channel currents and conductances from those of the short electrical channels are reported. 展开更多
关键词 bipolar field-effect transistor theory MOS field-effect transistor simultaneous electron and hole surface andvolume channels surface potential short channel theory double-gate pure-base
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The Bipolar Field-Effect Transistor:Ⅳ.Short Channel Drift-Diffusion Current Theory(Two-MOS-Gates on Pure-Base)
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作者 揭斌斌 薩支唐 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第2期193-200,共8页
This paper gives the short channel analytical theory of the bipolar field-effect transistor (BiFET) with the drift and diffusion currents separately computed in the analytical theory. As in the last-month paper whic... This paper gives the short channel analytical theory of the bipolar field-effect transistor (BiFET) with the drift and diffusion currents separately computed in the analytical theory. As in the last-month paper which represented the drift and diffusion current by the single electrochemical (potential-gradient) current, the two-dimensional transistor is partitioned into two sections, the source and drain sections, each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is then obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and the drift and diffusion components of the electron-channel and hole-channel currents and output and transfer conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the two-section short-channel theory from the one-section long-channel theory are described. 展开更多
关键词 bipolar field-effect transistor theory MOS field-effect transistor simultaneous electron and hole surface and volume channels surface potential two-section short-channel theory double-gate pure-base
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Ion Product of Pure Water Characterized by Physics-Based Water Model
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作者 揭斌斌 蕯支唐 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2016年第2期167-170,I0001,共5页
Pure water has been characterized for nearly a century, by its dissociation into hydronium (H3O)1+ and hydroxide (HO)1- ions. As a chemical equilibrium reaction, the equilibrium constant, known as the ion product... Pure water has been characterized for nearly a century, by its dissociation into hydronium (H3O)1+ and hydroxide (HO)1- ions. As a chemical equilibrium reaction, the equilibrium constant, known as the ion product or the product of the equilibrium concentration of the two ion species, has been extensively measured by chemists over the liquid water temperature and pressure range. The experimental data have been nonlinear least-squares fitted to chemical thermodynamic-based equilibrium equations, which have been accepted as the industrial standard for 35 years. In this study, a new and statistical-physics-based water ion product equation is presented, in which, the ions are the positively charged protons and the negatively charged proton-holes or prohols. Nonlinear least squares fits of our equation to the experimental data in the 0-100℃ pure liquid water range, give a factor of two better precision than the 35-year industrial standard. 展开更多
关键词 Solid state physics Liquid state chemistry Pure water Ion product Positiveproton Negative proton-hole or prohol
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The Bipolar Field-Effect Transistor:II.Drift-Diffusion Current Theory(Two-MOS-Gates on Pure-Base)
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作者 薩支唐 揭斌斌 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第12期1849-1859,共11页
This paper describes the drift-diffusion theory of the bipolar field-effect transistor (BiFET) with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin-pure-base. Analytical solution is obt... This paper describes the drift-diffusion theory of the bipolar field-effect transistor (BiFET) with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin-pure-base. Analytical solution is obtained by partitioning the two-dimensional transistor into two one-dimensional problems coupled by the parametric sur- face-electric-potential. Total and component output and transfer currents and conductances versus D. C. voltages from the drift-diffusion theory, and their deviations from the electrochemical (quasi-Fermi) potential-gradient theory,are presented over practical ranges of thicknesses of the silicon base and gate oxide. A substantial contri- bution from the longitudinal gradient of the square of the transverse electric field is shown. 展开更多
关键词 bipolar field-effect transistor theory MOS field-effect transistor simultaneous electron and holesurface and volume channels surface potential~ longitudinal gradient of transverse electric field
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