principle of least effort

In this paper we extend some concepts of tournaments to 2-tournaments, give conditions for an arbitrary nonegative integers vector to be score vector, obtain the relation among the number of 3-cycles, 2-cycles of a 2-tournament and its score vector a, and obtain the maximum and minimum number of 2-cycles with prescribed score vector s, partly answer a open problem of [4].

本文考虑以允许平局的单循环比赛为模型的２－竞赛图（二重完全图的定向图）和它的邻接矩阵（２－竞赛矩阵）得到了得分向量与２－圈数，３－圈数之间的关系；给出了构造最省和最奢的２－竞赛矩阵的方法；部分地回答了文献［４］中的一个问题。

Based on the extreme value of the function, the structure size for most saving material of the cylindrical shell subjected to internal pressure was calculated in this paper.

本文运用函数极值概念,对内压圆筒形壳体的最省料结构尺寸进行了推导,并用数值计算理论得出了工程实用的计算公式,对其误差也进行了合理的分析。

The interception orbit through two fixed points in space is studied by using mathematic methods and the conditions of minimum-energy and minimum-time interception are given respectively.

以数学方法对过空间两固定点的拦截轨道进行了分析,给出了快速拦截轨道和能量最省拦截轨道的条件。

A novel rapid method to design optimal-fuel interplanetary trajectory for low-thrust propulsion is presented based on normal trajectory approach.

针对星际探测任务中燃料最省小推力转移轨道问题,提出一种基于标称轨道的快速设计方法。