根的

Studying the positive definitiveness of the covariance matrix from discrete data is important to design the sampling plan and provides the base for the data analysis.However, there have been few outcomes about the positive definitiveness of covariance matrix, most of which have been restricted to the Covariance-matrix of continuous sample.

研究离散型样本协方差矩阵的正定性有助于判断是否可以降低样本的维数，有利于优化抽样个数，为抽样调查的优化设计方案提供一定的理论基础；为基于特征根的多元统计分析提供理论指导。

150 Chapter 1 The History and Future of Computers 3.2 Boolean Algebra Table 3-2 Distributivity Idempotency Absorption laws 分配律同一律吸收律 a=ab+ac a+= a+a=a aa=a a+ab=a a=a'=a'b''=a'+b' DeMorgan's laws德摩根定理计算机专业英语 1-151 Chapter 1 The History and Future of Computers 3.2 Boolean Algebra Since a finite set of n elements has exactly 2n subsets, and it can be shown that the finite Boolean algebras are precisely the finite set algebras, each finite Boolean algebra consists of exactly 2n elements for some integer n.

由于n个元素的有限集有且只有个子集由于个元素的有限集有且只有2n个子集，而且很显然有限布个元素的有限集有且只有个子集，尔代数一定是有限集合代数，所以对某个整数n而言而言，尔代数一定是有限集合代数，所以对某个整数而言，每个有限布尔代数也有且只有2n个元素。例如，上文定义的集合T的限布尔代数也有且只有个元素。

31 Chapter 3 Number Systems and Boolean Algebra 3.2 Boolean Algebra Table 3-2 Distributivity Idempotency Absorption laws 分配律同一律吸收律 a=ab+ac a+= a+a=a aa=a a+ab=a a=a'=a'b''=a'+b' DeMorgan's laws德摩根定理计算机专业英语 3-32 Chapter 3 Number Systems and Boolean Algebra 3.2 Boolean Algebra Since a finite set of n elements has exactly 2n subsets, and it can be shown that the finite Boolean algebras are precisely the finite set algebras, each finite Boolean algebra consists of exactly 2n elements for some integer n.

由于n个元素的有限集有且只有个子集由于个元素的有限集有且只有2n个子集，而且很显然有限布个元素的有限集有且只有个子集，尔代数一定是有限集合代数，所以对某个整数n而言而言，尔代数一定是有限集合代数，所以对某个整数而言，每个有限布尔代数也有且只有2n个元素。例如，上文定义的集合T的限布尔代数也有且只有个元素。

This work resulted, contrary to my own expectation, in the first direct experimental proof…of the Einstein equation and the first direct photo-electric determination of Planck's h.

密立根的诺贝尔获奖演说中的一些内容仍然表明他对其工作真正意义的抗拒："与我的期望截然相反，这项工作第一次直接实验验证了爱因斯坦的光电方程，并第一次直接测量得到了普朗克常数"。

Using the length of cells' growth cycle,the density of cells and the activity of induced hydrogenase as criteria,the optimal formulation of culture medium was obtained as seTA(se -Tris Acet) which contains acetic acid as C source,higher concentration of N and stronger pH buffer system based on the se formulation.

结果发现，培养基的pH和氮素的含量是影响莱茵衣藻生长的重要因素；而培养基中醋酸根的含量则有助于提高厌氧产氢过程中衣藻的氢酶活性，从而提高其产氢量。

Forces of 15 g for the fine root of a lower incisor and 60 g for a molar are sufficient for slow extrusion.

部队的15政的细根的门齿，并降低60克的摩尔有足够的缓慢挤压。

In this dissertation, we mainly focus on the computation of Jones polynomial and some its related polynomials of links in knot theory and analyze the distribution of their zeros.

本论文主要研究扭结理论中链环的Jones多项式和一些相关多项式的计算以及Jones多项式的根的分布，使用的方法基本上是组合方法。

There are the feelings of shy, confused, object, dislike at young girl's menarche.

她的绘画里，有代表男根的强壮的株型，也有代表女性的柔美的圆形。

Began to understand oneself at last, it is known that one's own emotion was so special, the muddleheaded emotion eager to express, like a cloud without root, is so helpless.

终于开始了解自己，知道了自己的感情是那么的特殊，而懵懂却急于表达的感情却象一片无根的云，是那么的无助。

It is joked by singers that Wagner's character of Siegfried in Der Ring des Nibelungen ought to have been called S ah gfried as his name is sometimes pronounced that way by sopranos looking to get the most volume out of their voices.

歌唱家中流传的笑话说瓦格纳《尼伯龙根的指环》中的角色齐格弗里德应该被称为"查"格弗里德，因为女高音为了提高她们的声量时偶然会这么唱他的名字。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。