A Distance-Regular Graph with Strongly Closed Subgraphs

Let be a distance-regular graph of diameter d, valency k and r := maxi | (c _i,b _i) = (c ₁,b ₁). Let q be an integer with r + 1 q d – 1.In this paper we prove the following results: Theorem 1 Suppose for any pair of vertices at distance q there exists a strongly closed subgraph of diameter q containing them. Then for any integer i with 1 i q and for any pair of vertices at distance i there exists a strongly closed subgraph of diameter i containing them. Theorem 2 If r 2, then c _2r+3 1.As a corollary of Theorem 2 we have d k ²(r + 1) if r 2.     

弱闭T(N)-模的预零化子的等距映射

本文刻划了弱闭T(N)-模的预零化子间的等距映射.设u,W分别为由左连续序同态N→~N和N→~N所确定的弱闭T(N)-模, u(?),W(?)分别为u,W的预零化子,Φ为由u(?)到W(?)上的线性等距映射.若(0)*=(0)#=(0),dim(0)+≠1且min{dim(H(?)~H),dim(He(?)^H)}≥2,则存在酉算子Ui,Vi(i=1,2),使得Φ(A)=U1AV*1或Φ(A)=U2A*V2*.     

氢负离子在微腔中的光剥离研究

利用闭合轨道理论,研究了氢负离子在金属面和弹性界面组成的微腔中的光剥离截面.结果表明,微腔的上下表面对氢负离子的光剥离截面产生很大影响.若固定金属面与氢负离子之间的距离不变,当弹性界面与氢负离子之间的距离很大时,弹性界面对氢负离子光剥离截面的影响很小,光剥离截面的振荡幅度和振荡频率与只有金属面时的情况类似.随着弹性界面和氢负离子之间距离的不断减小,光剥离截面的振荡幅度增大,振荡频率减小.若保持氢负离子和弹性界面之间的距离不变,随着金属面和氢负离子之间距离d₀的不断增大, 关键词： 光剥离截面 闭合轨道理论 微腔     

基于格子玻尔兹曼的两相闭式环路热虹吸研究

两相闭式环路热虹吸(CLTPT)形成定向循环的动力来源是重力在蒸发器和冷凝器之间形成的压力差。本文通过修改Gong-Cheng相变LBM模型中重力项计算方式,成功模拟了CLTPT在沸腾和凝结相变共同作用下产生的自驱动现象,揭示了不同充液率下的多种两相流型的存在。发现对于本文设计的热虹吸管结构,在初始状态液相覆盖全部蒸发段的前提下,充液率越小,CLTPT的周期性越复杂,越难达到稳定运行状态,系统自循环时均质量流量更小,同时蒸发段时均温度更低。     

正方体量子台球的半经典分析(英文)

近几年,量子台球问题引起人们的广泛兴趣.以前有很多对二维量子台球做过研究,相对于二维台球来说,三维台球更接近实际体系.本文以三维正方体量子台球为例,利用半经典闭合轨道理论计算了正方体量子台球中的经典开轨道,并研究量子谱函数与经典轨道长度之间的对应关系,发现他们之间对应的很好.这将有助于我们分析开放型量子台球中输运性质问题.利用这种方法物理图像清晰,计算量小并且可以帮助理解一些混沌体系的性质.这是半经典理论为联系量子力学与经典力学起桥梁作用的又一证明.     

光栅莫尔条纹在机床数控改造中的应用研究

从机床数控改造的实际出发,针对我国目前国产机床加工精度普遍不高,数控化程度较低等问题,提出了一种全新的设计方案,利用光栅作为位置检测元件,形成全闭环控制系统,结果表明既能够大大提高零件的加工精度,又能节省改造成本,为机床数控改造提供了参考。     

Spaces of Densely Continuous Forms, USCO and Minimal USCO Maps

Our paper studies the topology of uniform convergence on compact sets on the space of densely continuous forms (introduced by Hammer and McCoy (1997)), usco and minimal usco maps. We generalize and complete results from Hammer and McCoy (1997) concerning the space D(X,Y) of densely continuous forms from X to Y. Let X be a Hausdorff topological space, (Y,d) be a metric space and D _k (X,Y) the topology of uniform convergence on compact sets on D(X,Y). We prove the following main results: D _k (X,Y) is metrizable iff D _k (X,Y) is first countable iff X is hemicompact. This result gives also a positive answer to question 4.1 of McCoy (1998). If moreover X is a locally compact hemicompact space and (Y,d) is a locally compact complete metric space, then D _k (X,Y) is completely metrizable, thus improving a result from McCoy (1998). We study also the question, suggested by Hammer and McCoy (1998), when two compatible metrics on Y generate the same topologies of uniform convergence on compact sets on D(X,Y). The completeness of the topology of uniform convergence on compact sets on the space of set-valued maps with closed graphs, usco and minimal usco maps is also discussed.     

Lienard系统的同宿轨族与闭轨族

本文讨论Ｌｉｅｎａｒｄ系统解的一些定性性质，得到了存在同宿轨族、闭轨族、双曲扇形和椭圆扇形、正负半轨有界及其与等倾线相交的充要条件或充分条件．