负阻效应的原理与应用

在对负阻元器件特性进行研究和分析的基础上引出负阻效应的概念,对负阻效应产生方式和原理进行了论述。NIC(Negative Impedance Converter)是一种广泛运用于设计的负阻抗器件,提出了两种构成NIC的方式,给出了利用NIC来实现阻抗变换的设计原理和方法。运用由运算放大器构成的NIC对现有的LC阻尼振荡实验进行了改进,并给出了具体的电路,使实验结果更接近理论分析结果,还可使观察到的实验现象更加多样化。对负阻效应在几种实际电子线路中的应用进行了研究和总结。     

负阻特性的研究

本文详细介绍了负电阻的特性、分类及负电阻在振荡器中的应用,并从定性与定量两方面分析了负阻振荡器的原理。     

PLBT硅光电负阻器件及光控正弦波振荡器

首次报道了 PL BT硅光电负阻器件及光控正弦波振荡器的初步研究结果 ,介绍了硅光电负阻器件 (PL BT)的特性并对用该器件所构成的光控正弦波振荡器进行了实验研究     

后差变换开关电容RLC仿真电路

本文采用后差变换,提出实现模拟电阻,电感和电容特性的开关电容仿真电路的新原理。设计並实验了开关电容负阻变换器和电感仿真电路。实验了采用这种仿真电感的科皮兹正弦波振荡器。电路是全相输入和全相输出,实际采样频率是时钟频率的2倍。     

半导体激光器和光晶体管组合双稳的研究

利用光晶体管的饱和特性和雪崩负阻特性实现了半导体激光器和光晶体管的组合双稳,并对影响其工作状态及特性的条件进行了讨论。     

静电感应晶闸管负阻特性的数值模拟

运用半导体器件数值模拟中的漂移-扩散模型,对静电感应晶闸管(SITH)的负阻转折特性进行了模拟和分析.通过对器件内场和载流子分布的模拟,揭示了SITH的负阻转折特性是源于高电平下双注入的加强以及伴随的耗尽层的收缩.模拟结果与实验结果吻合较好,对器件的设计与优化具有指导意义.     

薄基区异质结晶体管的负阻特性与分析

采用分子束外延方法生长了8 nm基区的InGaP-GaAs双异质结材料,研制成具有负阻特性的异质结晶体管．该晶体管可以集成在高速高频的数字逻辑电路中,大大减少了器件数目．讨论了薄基区负阻异质结晶体管的负阻特性及其物理机制．器件负阻特性的产生与其结构密切相关,包括导带势垒尖峰和基区宽度负反馈效应．推出了物理公式,并且使用PSPICE模拟软件建立了电路模型．模拟结果符合制作器件的测量结果．     

基于负载谐振的等离子点火器的实验研究

本文基于地空导弹用于导弹续航的二级发动机点火的特殊工作环境和辉光放电的负阻特性，提出了一种串并联谐振DC／DC变换器的电路拓扑．充分利用高频变压器漏感与寄生电容产生谐振谐振，在创造开关管ZVS的条件，提供吸收变压器漏感的能量的路径，减少开关应力的同时，实现了点火装置高功率密度、高效和小型化的优点，满足了不断发展的导弹点火装置的需求．在理论分析的基础上，利用ORCAD进行了仿真，仿真结果证明了理论分析的正确性。     

OPA型阻抗变换器的一种综合法

介绍了用两只通用运算放大器和少量电阻、电容综合阻抗变换器的一种方法。用此方法设计出输入阻抗为电感、频变负电阻和负电阻三种有源模拟电路。     

锗合金扩散晶体管负阻特性的研究

兰大技革组已从实验上发现,只要时3AG63锗合金扩散晶体管进行适当地脉冲“处理后”,它的Ⅰ-Ⅴ特性就具有典型的负阻特性。文中探讨了这种负阻现象的物理机理,借用电子计算机求解了热—电传导方程式,所得结果同实验一致。     

复阻抗谱数据处理研究

本文在总结前人对复阻抗谱处理研究的基础上,用系统方法导出了组合柯尔-柯尔模型的乘积形式,进而提出了用对数形式的柯尔-柯尔模型对复阻抗谱进行分段拟合的方法.拟合反演的初参由计算机自动选择.     

基于网络模型的节点阻抗矩阵的新算法

结合配电网结线图特点,建立了反映支路电流向节点分布规律的数学模型。在此基础上,根据节点阻抗矩阵各的元素的意义,提出了一种节点阻抗矩阵各元素的简单且准确的计算方法。     

基于网络模型的节点阻抗矩阵的新算法

结合配电网结线图特点 ,建立了反映支路电流向节点分布规律的数学模型。在此基础上 ,根据节点阻抗矩阵各元素的意义 ,提出了一种节点阻抗矩阵各元素的简单且准确的计算方法     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that