Highly edge‐connected detachments of graphs and digraphs

Let G = (V,E) be a graph or digraph and r : V → Z₊. An r‐detachment of G is a graph H obtained by ‘splitting’ each vertex ν ∈ V into r(ν) vertices. The vertices ν₁,…,ν_r(ν) obtained by splitting ν are called the pieces of ν in H. Every edge uν ∈ E corresponds to an edge of H connecting some piece of u to some piece of ν. Crispin Nash‐Williams 9 gave necessary and sufficient conditions for a graph to have a k‐edge‐connected r‐detachment. He also solved the version where the degrees of all the pieces are specified. In this paper, we solve the same problems for directed graphs. We also give a simple and self‐contained new proof for the undirected result. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 67–77, 2003     

Stable edge dislocations in finite crystals

Dislocations have been considered as mechanically unstable defects in bulk crystals, ignoring the Peierls oscillations. Eshelby [J. Appl. Phys. 24 (1953) p.176] had showed that a screw dislocation can be stable in a thin cylinder. In the current work, considering Eshelby's example of an edge dislocation in a single crystalline plate, we show that an edge dislocation can be stable in a finite crystal. Using specific examples, we also show that the position of stability of an edge dislocation can be off-centre. This shift in the stability from the centre marks the transition from a stable dislocation to an unstable one. The above-mentioned tasks are achieved by simulating edge dislocations using the finite element method.     

强激光远场焦斑重构算法研究

通过CCD图像采集单元结合传统的列阵相机测量高功率固体激光器的远场焦斑分布,采用图像处理技术的边缘算子提取焦斑的几何中心,提出通过几何中心对心的焦斑嵌套重构算法,解决了光斑饱和时的对心难题,实现了快捷准确测量激光焦斑,为激光器的实时控制提供参考数据。     

On the two methods of kinetic theory of ECRM

The kinetic theory based on the expansion of local field in the guiding center coordinate system, presented by paper[1]–[3], has successfully developed into a theoretical system. The mathematical background and physical explanation of setting up the guiding center coordinate system is expounded in the paper. By using the methods of the guiding center and waveguide coordinate systems respectively, the same dispersion equations for interaction of an axially symmetrical single momentum electron beam with TE_mn field in the circular waveguide are rigorously derived. A number of mistakes in paper[4] are indicated as well.     

生境片段化对千岛湖次生马尾松林土壤理化性质的影响

土壤是森林生态系统的重要组成部分,对森林生物多样性和生态功能的维持具有不可替代的作用.据此,本研究以千岛湖地区大陆35个样方和29个不同大小和隔离度的陆桥岛屿次生马尾松林土壤为研究对象,分析了生境片段化对土壤理化性质的影响.研究发现,大陆马尾松林土壤厚度显著高于岛屿,而其土壤最大持水量显著低于岛屿;大陆土壤的全磷（P）显著低于岛屿,而土壤有效磷（AP）和硝态氮（NO₃-N）显著高于岛屿.在片段化的岛屿生境中,土壤C、N、P、NO₃-N、AP随与边缘距离的增大而降低;隔离度和地形对部分土壤理化因子有影响,而岛屿面积对土壤理化性质无影响.土壤理化因子和植物群落多样性存在显著相关性.生境片段化改变了千岛湖地区马尾松林的土壤条件,而边缘效应是影响片段化生境中土壤性质空间分布的主要过程之一.通过分析片段化景观中土壤理化性质的空间分布格局及其影响因素,深化了生境片段化对土壤条件影响的认识,对于片段化森林管理措施的制定具有重要意义.     

256色模式下图形图像处理系统中对不规则区域的处理

概述了图形图像处理系统中关于不规则区域的基本算法，包括：区域填充，边界跟踪，边界标志，几何处理，区域分割等等．并且，根据２５６色模式的特殊性，对传统的算法做了有针对性的改进，加快了处理速度，使其更适合于电影电视字幕、动画卡通人物等不规则图形图像区域．同时还给出了改进算法的程序设计的技巧．     

0－1多面体图连通度猜想的一个反例

本文给出０－１多面体图连通度猜想的一个反侧．由此说明０－１多面体图的连通度未必等于最小度．     

答YapH.P.和TeoS.K.问题

本文证得：如果Ｆ是Ｃｎ中的一条种路，则Ｇ中同时通过ｋ余弦ｅ１，ｅ２，．．．，ｅｋ而不通过Ｆ中的任一条边的圈最多只有一个且Ｇ中同时通过ｋ条弦ｅ１，ｅ２，．．．，ｅｋ的圈最多只有２个，进而由之给出了Ｍ（ｋ）的上界和ｍ（ｋ）的下界及ｍ（ｋ）＝（ｋ＋１）（ｋ＋２）／２成立的一个条件，否定地回答了ＹａｐＨ．Ｐ．和ＴｅｏＳ．Ｋ．１９８４年提出的一个问题。     

SiH4凝聚态结构的近边X射线吸收精细结构研究

用多重散射团簇方法对低温下凝聚态SiH-4进行了Si的1 s NEXAFS理论研究,对不同的模型研究表明,此时凝聚相SiH-4形成链状结构.     

电视摄象机测量误差探讨

本文简述了用电视摄象机进行工业尺寸测量的微分法与拟合法的基本原理,同时详细的讨论了各自所能达到的精度极限。本文用实验验证了理论计算的结果,最后对二维工件测量时,如何根据工件的不同形状与位置以及光学系统的特点,提出了在测量时工件的放置应该注意的问题以及对工件拐角处如何进行处理的方法。