动态激光衍射法测量细丝直径

基于夫琅禾费衍射理论和巴比涅互补原理,提出了利用激光衍射对细丝直径进行动态测量的方法.该方法具有测量精度高、速度快、非接触、使用方便且易于微机联接实现自动化测量等优点.     

直径对脉冲爆震发动机性能的影响

本文通过实验研究了脉冲爆震发动机的直径对其性能的影响．实验结果表明；当爆震室的直径增大时，爆震波压力波形相似，平均峰值压力比较接近，且比冲基本保持不变，而推力则随爆震室直径的增大而增大。实验曲线表明爆震室内的流动具有自相似性，从而为建立尺寸律提供了实验依据．本文中比冲和平均推力是利用摆动原理测量的，并与由作用在推力壁上的压力计算得出的比冲和平均推力的理论值和实验值进行了比较，结果基本吻合，说明该测量方法可行．     

用毛细管测量纯水表面张力系数的误差讨论

通过用毛细管测量纯水表面张力系数实验，得到管内径d与接触角θ的相对误差之间的关系曲线，由此说明实验测得的表面张力系数α和理论公式相比呈现一定的偏差，并简单地讨论了实验的理想状态与实际情况的差别．     

A new method for constructing infinite families of k-tight optimal double loop networks

The double loop network (DLN) is a circulant digraph with n nodes and outdegree 2. DLN has been widely used in the designing of local area networks and distributed systems. In this paper, a new method for constructing infinite families of k-tight optimal DLN is presented. For k = 0,1,…,40, the infinite families of k-tight optimal DLN can be constructed by the new method, where the number nk(t,a) of their nodes is a polynomial of degree 2 in t and contains a parameter a. And a conjecture is proposed.     

利用弧形光栅尺测量大型转轴扭矩的原理研究

利用弧形光栅尺的旋转微位移测量功能,组建一组测量体系,用于测量巨型转轴的扭矩。采用四组相同的弧形光栅尺同时测量两截面的相对转角,通过多点测量实现误差均化,得出了消除转轴直径对测量影响的公式,使仪器的环境适应能力得到了极大地提高。根据不同的工作情况,提出了相应的动态测量扭矩的计算方程。实现了大型机械设备主传动的动力监测,为设备自动化、智能化奠定了基础。     

直径不超过4的树的割宽

§ 1　IntroductionThe cutwidth problem for graphs,as well as a class of optimal labeling and embed-ding problems,have significant applications in VLSI designs,network communicationsand other areas (see [2 ] ) .We shall follow the graph-theoretic terminology and notation of [1 ] .Let G=(V,E)be a simple graph with vertex set V,| V| =n,and edge set E.A labeling of G is a bijec-tion f:V→ { 1 ,2 ,...,n} ,which can by regarded as an embedding of G into a path Pn.Fora given labeling f of G,th…     

Results of the maximum genus of graphs

In this paper,we provide a new class of up-embeddable graphs,and obtain a tight lower bound on the maximum genus of a class of 2-connected pseudographs of diameter 2 and of a class of diameter 4 multi-graphs.This extends a result of Skoviera.     

一类几乎最优循环图{C_p(m,m+1,p/a)}

本文比较了循环图类{c_p(n_1,…,n_p)}和{c-p(n_1…,n_p,p/α)}的直径下界。对于p和α满足一定条件的循环图类{c_p(n_1,n_2,p/α)},本文给出了达到或几乎达到此图类直径下界的一类几乎最优循环图{c_p(m,m+1,p/α)}。     

The construction of infinite families of any k-tight optimal and singular k-tight optimal directed double loop networks

The double loop network(DLN)is a circulant digraph with n nodes and outdegree 2.It is an important topological structure of computer interconnection networks and has been widely used in the designing of local area networks and distributed systems.Given the number n of nodes,how to construct a DLN which has minimum diameter?This problem has attracted great attention.A related and longtime unsolved problem is:for any given non-negative integer k,is there an infinite family of k-tight optimal DLN?In this paper,two main results are obtained:(1)for any k≥0,the infinite families of k-tight optimal DLN can be constructed,where the number n(k,e,c)of their nodes is a polynomial of degree 2 in e with integral coefficients containing a parameter c.(2)for any k≥0, an infinite family of singular k-tight optimal DLN can be constructed.