两分

This article discusses two types of clustered network topology: homogeny cluster head hierarchical topology and heterogeneous cluster head hierarchical topology.

本文讨论了两种拓扑结构：簇头异构的分簇式网络拓扑结构和簇头同构的分簇式网络拓扑结构。

The anatomical study deepens the knowledge of G-type conducting cells: 1 It proves the theory of two depositional process for secondary wall (Bierhorst, 1960): the discontinuous cellulose layer is laid down before the continuous lignified layer; the former layer is prone to be broken down, while the latter is highly decay-resistant; 2 It suggests that the cellulose primary and secondary walls of tracheids are not perforated. Instead of longitudinal pits (Li, 1992), the lignified tracheid secondary wall of Hsüa possesses irregular simple perforations; 3 In Hsüa reflexa and Huia gracilis, the perforation casts may represent the thickness of lignified secondary wall; 4 The wall structure of G-type tracheid is diversified. At the genus level, the secondary wall structure differs in the distribution, internal shape and structure of the perforations; 5 Perforations of some G-type tracheids combine the characters of S-type tracheids in their distribution, density and diameter.

解剖学的研究加深了对G-型输水管胞的认识 1）验证了管胞次生壁分两个阶段形成的理论（Bierhorst，1960），即先后形成不连续的纤维质层和连续的木质化层，前者易被分解，后者抗侵蚀性强；2）证明管胞纤维质的初生壁和次生壁不具穿孔，Hsüa管胞的木质化次生壁具有不规则的简单穿孔，而不是纵列的纹孔（Li，1992）；3）Hsüa reflexa和Huia gracilis的穿孔铸体可代表木质化次生壁的厚度；4）G-型管胞壁层结构具多样性，植物属一级的分异主要表现在次生壁穿孔的分布、孔腔形状和结构的不同；5）某些G-型管胞的穿孔在其分布、密度和孔径方面可兼有S-型管胞的特征。

In order to save the rare expensive iceland crystal material and realize the 90° beam splitting on the base of high transmissivity and high extinction ratio, using two pieces of ZBaF3 glass and one iceland crystal slice, a new type of 90° beam splitting polarized prism was designed.

为了节省冰洲石晶体材料，并且在保证偏光棱镜高透射比和消光比的情况下实现光路的90°分束，采用在两块ZBaF3玻璃中间胶合冰洲石晶体薄片的三元结构方案，设计了一种新型的90°分束偏光棱镜。

This thesis carries on research to a class of nonlinear Schrodinger Equation with wave operator of initial value periodic problem.

本文针对一维带波动算子的Schrodinger方程周期初值问题进行数值研究，对上述方程首先构造了守恒的半离散格式，然后将p次Hermite插值方法与有限差分方法相结合构造了差分正交样条配置格式，并证明这两个格式均为稳定和收敛的格式。

A structure of space-time diversity virtual double-route weighting interference mitigating is proposed, and the corresponding practical algorithm is derived in detail using block matrix inversion formula and matrix inversion theory for mitigating interference signals from both other cells and other users of local cell in the DS-CDMA up-link communication case. Performances of such algorithm are thoroughly analyzed through simulation and analytical results. The up-link and down-link channel characters and their relationship of DS-CDMA communication system are thoroughly analyzed, and the relationship of space-time diversity weighting matrix between time division duplexing and frequency division duplexing these two different transmission ways is derived.

本论文深入地比较了DS-CDMA通信系统的上传情形与下传情形的信道特性及其它们相互之间的关系；深入地分析并得到了时分双工和频分双工两种不同的传输模式下的上传情形与下传情形的空时分集权系数矩阵之间的数量关系，从而使得能够利用在基站端所拥有的上传情形的空时分集接收权系数矩阵信息以及其他信息在基站端直接形成空时分集发射权系数矩阵；推导了下传情形移动用户接收机端的最优组合接收策略及其算法；进一步地，对时分双工传输模式下的下传情形的通信系统性能和频分双工传输模式下的下传情形的通信系统性能进行了深入的比较仿真研究。

In this paper,we give the error expressions of piecewise linear Lagrange polynomial interpolation and piecewise cubic polynomial interpolation using the Taylor expansions.

中文摘要：本文利用Taylor展开得到三角形上线性Lagrange插值和三次Lagrange插值的导数余项公式，对这些余项公式进行分析，给出了两类能以四阶精度逼近被插函数在对称点的导数值的格式，一种是在均匀剖分时其分片线性插值的相邻单元的导数值的后处理格式，一种是在六片强正规剖分时的三次插值在对称点上的导数值的后处理格式，使得在已知原函数在各节点的值后，通过一个简单的线性计算就可得到原函数在对称点的导数的一个超逼近值，将以往提出的平均导数的二阶精度提高到四阶。

The input - output relationship of any linear time-invariant discrete system can be described by a difference equation The complete solution of a linear difference equation consists of two parts: the free component and the forced component.

任何一个线性时不变离散系统的输入输出关系都可用线性差分方程式来描写。差分方程式的解答包括两部分：即自由分量和强制分量。

Singular value decomposition and Least Squares QR factorization are two basic methods for a linear equation group in seismic tomography.

奇异值分解法和最小平方QR分解法是求解反演成像中线性方程组的两种基本解法。

Because of the condition of 〓 for two neighbour parametricspline surfaces is too strong,here,instead of it,some simple and practicableconditions of 〓 resulted from the general theorem obtained by Prof.LiuDing Yuan in Chapter 1 were proved,and three 〓 triangular splinesurfaces schemes wre presented:one is piecewise cubic spline surface patcheshaving local 〓 and whole 〓 continuity based on the refined HCTtriangulation,another is the same degree spline surface patches but based onthe refined Powell-Sabin triangulation,the third is piecewise quartic splinesurface patches having local 〓 and whole 〓 continuity based on therefined P-S triangulation.

由于对参数曲面，一阶导数连续的要求较强，我们采用第一章从刘鼎元定理导出的简单实用的几何连续条件，讨论了基于HCT加细三角剖分和P-S加细三角剖分上的两种局部达一阶导数连续而整体有一阶几何连续的分片三次样条曲面构造算法，一种局部达二阶导数连续整体有一阶几何连续的分片四次样条曲面构造方法。

Plant flower can be divided into two phases——from stem apex meristem tissue into flower meristem tissue and floral apparatus.

高等植物的成花可分为两个阶段：由茎顶端分生组织转变成花分生组织和花器官的形成。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。