非腔长匹配相干叠加脉冲锁模激光器的理论研究

提出了一个新的非腔长匹配相干叠加脉冲锁模激光器的物理模型,建立了它的数学方程,并进行了模拟计算.计算结果给出了各个参数对相干叠加脉冲锁模激光器运转的影响,以及脉冲宽度压缩速度和各参数之间的关系,获得了实现非腔长匹配相干叠加脉冲锁模激光器运转的最佳条件.     

Effect of strain on vibrational modes in strained layer superlattices

We have investigated the lattice vibrational properties of a two-component strained layer semiconductor superlattice (GaAs) _n1 (GaSb) _n2 using a one-dimensional linear chain model and transfer matrix method [1]. Effect of strain, arising due to the lattice mismatch (∼ 7%) has been considered explicitly in the equation of motion. We show for the first time that the optical vibrational frequency increases (in the case of (GaAs)₄ (GaSb) _n ) or decreases (in the case of (GaAs) _n (GaSb)₄) with increase of layer thicknessn, in either type of superlattices. Raman scattering measurements on some other similar systems support our findings.     

多晶硅发射极晶体管的数值分析及模拟

通过对多晶硅发射极晶体管（ＰＥＴ）的多晶硅及界面层导电特性的分析， 得到单晶发射区边界上电流密度与少子浓度之间的关系式，并以此为自洽的 边界条件，在单晶区数值求解一组描述晶体管电学特性的微分方程，得到晶 体管内部电势分布和载流子分布以及ＰＥＴ的端电流特性．     

Extracting multiple layers from data having graph structures

Much data such as geometric image data and drawings have graph structures. Such data are called graph structured data. In order to manage efficiently such graph structured data, we need to analyze and abstract graph structures of such data. The purpose of this paper is to find knowledge representations which indicate plural abstractions of graph structured data. Firstly, we introduce a term graph as a graph pattern having structural variables, and a substitution over term graphs which is graph rewriting system. Next, for a graph G, we define a multiple layer (g, (θ1,…,θk)) of G as a pair of a term graph g and a list of k substitutions θ1,…,θk such that G can be obtained from g by applying substitutions θ1…,θk to g. In the same way, for a set S of graphs, we also define a multiple layer for S as a pair (D,Θ) of a set D of term graphs and a list Θ of substitutions. Secondly, for a graph G and a set S of graphs, we present effective algorithms for extracting minimal multiple layers of G and S which give us stratifying abstractions of G and S, respectively. Finally, we report experimental results obtained by applying our algorithms to both artificial data and drawings of power plants which are real world data.     

空间发展湍流气粒两相平面混合层的大涡模拟与统计

本文对空间发展的湍流气固两相平面混合层流动进行了大涡模拟研究,其中气相亚网格尺度（SGS）使用结构函数模型,气相控制方程组采用SIMPLE方法求解,固体颗粒运动用拉格朗日方法计算。计算结果正确重现了流体涡结构的卷起、合并和破碎过程,以及小尺寸颗粒在涡边缘（低涡度区）的局部富集现象。对直径分别为42μm、72μm和135μm分别进行了模拟,并将统计结果和实验测量结果（Hishida　et　al[1]）比较,表明两者的平均速度吻合很好,但颗粒数密度和脉动速度存在较明显的差异,因此有必要对亚网格应力和颗粒之间的耦合作用以及拟序结构的三维性对颗粒运动的影响开展深入研究。     

基于PML边界的有限差分法及其在光波导泄漏损耗计算中的应用

利用结合完美匹配层(PML)边界的有限差分法计算了光波导的泄漏损耗.通过采用非均匀格点差分格式和反正切坐标变换的方法,有效地减小了计算量并提高了计算精度.分析了PI(polyimide)掩埋型波导和SOI(silicon-on-insulator)脊型波导两种典型结构的泄漏损耗,给出了波导结构尺寸对泄漏损耗的影响,并对有效减小泄漏损耗的方法进行了讨论.     

时域有限差分法在光波导分析中的应用及改进

对时域有限差分算法在圆柱坐标下弱导光纤中应用时吸收边界条件的设置及其对计算精度的影响进行了讨论，提出了改善的方法。并且将这种方法应用于一般光纤和光电子晶体光纤传输特性的计算，得到了有用结果。     

On the theory of adsorption kinetics of ionic surfactants at fluid interfaces

The kinetic equation to describe the adsorption process of ionic surfactants (derived in part 1) will be solved numerically. The results show the effect of parameters such as ion valencyz, thickness of theDL x ^–1, and surfactant parameters_eq,K, andK _ads on the adsorption process. The results can be used to decide whether the model can explain experimental data on charged surfactant molecules or not.Nomenclature c concentration - c_e bulk concentration in equilibrium - C =c/c _e dimensionless concentration - D diffusion coefficient - e proton charge - F Faraday's constant - f ₀ =e/kTdimensionless potential - k Bolzmann's constant - K _ads rate constant of adsorption - K _des rate constant of desorption - K(f ₀) coefficient of electrostatic deceleration - K = _eq /c _e Henry's constant - R gas law constant - t time - T absolute temperature - z electrovalence - ₀ adsorption of ions - _eq equilibrium value of _o - = ₀/ _eq dimensionless adsorption - , constants - dielectric constants - x Debye-Hückel reciprocal distance - =Dt/K ² dimensionless time - electric potential     

NdAl_3(BO_3)_4晶体的结晶习性和缺陷

本文研究了 NAB 晶体的宏观形态、表面形貌以及蚀坑的几何取向,得到了一些有价值的结果。肯定了 NAB 晶体的对称性,并发现了该晶体中存在异结构夹层,它们和[101] 方向约成60Ⅰ°交角,层状分布在晶体之中。最后讨论了NAB 晶体的结构。