指导nM0S数字电路元件级设计的开关信号理论

本文指出了布尔代数在指导数字电路设计中的不足,并在区分描写开关状态与信号的二类变量的基础上建立了能反映数字电路内开关元件与信号相互作用过程的开关信号理论。本文把该理论具体用于对nMOs数字电路的研究,结果表明该理论可很好地指导nMOS数字电路在元件级的逻辑设计。     

基于Mie理论的微体缺陷激光测试技术的理论与实验研究

提出了一种基于瑞利散射定律及米氏理论(Rayleigh & Mietheory)的、在垂直于入射光方向接收散射光以极大提高衬度来检测材料内部微纳米级体缺陷的无损检测新途径,叙述了有关的理论基础,进行了系统的计算机仿真与实验研究,验证了理论的正确性及方案的可行性,说明利用光散射测量微纳米级体缺陷是可行的,进而为下一步的激光扫描层析技术(LST)打下了基础。     

群论在网络理论中的应用研究

本用群论研究了双口网络集合，双口理想换器与器件的集合，２ｎ端口理想变换器和器件的集合。     

基于开关信号理论的电流控阈技术及I^2L施密特电路

本文在开关－信号理论的指导下，采用电流信号表示逻辑值，对Ｉ＾２Ｌ电路中如何实现阈值控制进行了研究，在此基础上，提出了实现阈值控制电路的接地开关运算表示式，并用于设计相应的三值Ｉ＾２Ｌ施密持反相器电路，用ＰＳＰＩＣＥ程序模拟证明了所设计的电路具有理想的施密特电路特性。     

建立自然型实时语音讨论系统的双令牌方法

数字语音通信服务是ＣＳＣＷ应用系统的重要组成部分。本文首先分析了自然型语音通信所需遵循的规则，建议使用双令牌来控制发言权，并描述了一个基于双令牌的发言控制协议。在此基础上，我们给出了一个自然型多点语音讨论系统ＶｏｉｃｅＣｈａｔ的设计和实现方案，最后结合某段典型的对话情景给出了应用实例     

二维随机粗糙面的fBm模拟及其统计特性

数值模拟在物理建模中具有相当重要的地位。本文基于对二维分形布朗运动（ｆＢｍ）的研究，根据ｆＢｍ的特征，阐述了用二维ｆＢｍ函数模拟随机粗糙面的方法。由于很多电磁散射问题与粗糙面的各阶矩有很大的关系，我们导出了二维随机粗糙面的统计参量与分维Ｄ的关系。基于对二维ｆＢｍ的小波分析，提出了在时－频相空间估计分维Ｄ的方法。这种方法比较简单而切实可行，不但适合于粗糙面整体分维的计算，更适合于局部分数维的计算。所     

Hyperconifold transitions,mirror symmetry,and string theory

Multiply-connected Calabi–Yau threefolds are of particular interest for both string theorists and mathematicians. Recently it was pointed out that one of the generic degenerations of these spaces (occurring at codimension one in moduli space) is an isolated singularity which is a finite cyclic quotient of the conifold; these were called hyperconifolds. It was also shown that if the order of the quotient group is even, such singular varieties have projective crepant resolutions, which are therefore smooth Calabi–Yau manifolds. The resulting topological transitions were called hyperconifold transitions, and change the fundamental group as well as the Hodge numbers. Here Batyrev?s construction of Calabi–Yau hypersurfaces in toric fourfolds is used to demonstrate that certain compact examples containing the remaining hyperconifolds — the Z₃${\mathbb{Z}}_3$ and Z₅${\mathbb{Z}}_5$ cases — also have Calabi–Yau resolutions. The mirrors of the resulting transitions are studied and it is found, surprisingly, that they are ordinary conifold transitions. These are the first examples of conifold transitions with mirrors which are more exotic extremal transitions. The new hyperconifold transitions are also used to construct a small number of new Calabi–Yau manifolds, with small Hodge numbers and fundamental group Z₃${\mathbb{Z}}_3$ or Z₅${\mathbb{Z}}_5$. Finally, it is demonstrated that a hyperconifold is a physically sensible background in Type IIB string theory. In analogy to the conifold case, non-perturbative dynamics smooth the physical moduli space, such that hyperconifold transitions correspond to non-singular processes in the full theory.     

Piezoelectricity of ordered (ScxGa1-xN) alloys from first principles

First-principles calculations are performed to compute the e₃₃ piezoelectric coefficients of GaN, ScN and (Sc_xGa_1-xN) alloys exhibiting an alternation of hexagonal GaN, with hexagonal ScN along the c-axis. For Sc compositions larger than 50%, each atom has nearly five nearest neighbors (i.e., the ground state exhibits a phase that is five-fold coordinated). On the other hand, Sc-deficient (Sc, Ga) N alloys adopt a ground-state that is four-fold coordinated). The magnitude of e₃₃ in the Sc-deficient ideally ordered (Sc_0.25Ga_0.75N) is found to be larger than the magnitude of the corresponding e₃₃ coefficients resulting from the compositional weighted average over the hexagonal (h-ScN) and the wurtzite (w-GaN) parent compounds. On the other hand, the e₃₃ coefficients of the Sc-rich ordered (Sc_0.75Ga_0.25N) is found to be negligibly small. In addition, e₃₃ piezoelectric coefficients in ordered (Sc_0.5Ga_0.5N) exhibit quite large magnitudes, due to the nonpolar to polar transition occurs at Sc composition x = 0.5, and thus can bridge the corresponding coefficients of (Ga, In) N and ferroelectric alloys. The microscopic origins for this huge enhancement in the piezoelectric behavior in Sc-low and Sc-intermediate alloys and the role of each atom are revealed and discussed.     

Relation between Hall-magnetohydrodynamics and the kinetic Alfvén wave

Effects of a finite ion temperature on the Hall magnetohydrodynamics (MHD), which breaks down for a finite ion temperature, are clarified in terms of a rigorous three-field kinetic dispersion relation. The MHD mode equation becomes anisotropic with respect to the ion pressure because of the double adiabaticity in ion dynamics.