船速桨频测量仪研究

船速桨频测量仪是一种智能化测量仪器．单片微型计算机８７Ｃ５１是测量系统的核心．本文系统介绍其工作原理，软、硬件的设计方法．最后列举测试结果并进行误差分析     

基团转移聚合研究的最近进展

对基团转移聚合在引发剂、单体、催化剂、立体化学、嵌段和星型共聚物、终止反应、链转移反应以及应用方面的最近进展,进行了介绍和评述。     

基于光聚合星型PEG-b-PCL大分子单体可生物降解水凝胶的合成及表征

以辛酸亚锡为催化剂 ,通过星型聚乙二醇 (PEG)引发ε 己内酯 (CL)开环聚合 ,制备了PEG b PCL嵌段共聚物 ,进一步以丙烯酸酯封端 ,合成了 3种水溶性大分子单体 .以 2 ,2 二甲氧基 2 苯基苯乙酮为引发剂 ,在紫外光作用下 ,大分子单体在水中由于胶束的形成能够迅速聚合形成水凝胶 .利用1 H NMR、FTIR、DSC、TGA、ESEM、凝胶含量、溶胀比等分析测试手段对大分子单体及其形成的水凝胶进行了表征 .结果表明 ,干胶迅速吸水而达到溶胀平衡 ,水凝胶具有较大的溶胀比和高的水含量 ;随着PEG臂数的增加 ,干胶的熔融峰顶温度下降 ,凝胶的溶胀比减小 ;ESEM图片上清晰地表明水凝胶的网络结构     

The serial test for a nonlinear pseudorandom number generator

Let and A sequence is obtained by the formula The sequence is a sequence of pseudorandom numbers of the maximal period length if and only if (mod 4), (mod 4). In this note, the uniformity is investigated by the 2-dimensional serial test for the sequence. We follow closely the method of papers by Eichenauer-Herrmann and Niederreiter.

     

Pseudorandom vector generation by the compound inversive method

Pseudorandom vectors are of importance for parallelized simulation methods. In this paper a detailed analysis of the compound inversive method for the generation of -dimensional uniform pseudorandom vectors, a vector analog of the compound inversive method for pseudorandom number generation, is carried out. In particular, periodicity properties and statistical independence properties of the generated sequences are studied based on the discrete discrepancy of -tuples of successive terms in the sequence. The results show that the generated sequences have attractive statistical independence properties for pseudorandom vectors of dimensions .

     

Error Bounds for quasi-Monte Carlo integration with nets

We analyze the error introduced by approximately calculating the -dimensional Lebesgue measure of a Jordan-measurable subset of . We give an upper bound for the error of a method using a -net, which is a set with a very regular distribution behavior. When the subset of is defined by some function of bounded variation on , the error is estimated by means of the variation of the function and the discrepancy of the point set which is used. A sharper error bound is established when a -net is used. Finally a lower bound of the error is given, for a method using a -net. The special case of the 2-dimensional Hammersley point set is discussed.

     

Inversive congruential pseudorandom numbers: distribution of triples

This paper deals with the inversive congruential method with power of two modulus for generating uniform pseudorandom numbers. Statistical independence properties of the generated sequences are studied based on the distribution of triples of successive pseudorandom numbers. It is shown that, on the average over the parameters in the inversive congruential method, the discrepancy of the corresponding point sets in the unit cube is of an order of magnitude between and . The method of proof relies on a detailed discussion of the properties of certain exponential sums.

     

STUDY ON HIGH PERFORMANCE ANTI—WEAR ADDITIVES FROM WATER—SOLUBLE POLYMERIC LUBRICANT*

A series of high performance lubricants of water-soluble polymers with telechelic or starstructures has been studied. Their average molecular weights M are 1800--6000. The chemi-cal structures of the lubricants are characterized by their hydrophilic groups (--CH_2CH_2O--),--COOH, --OH, --CONH_2 and antiwear active elements (S, P,Zn and Mo). The results ofassessing for the anti-wear property indicate that this kind of water-soluble polymeric lubri-cants possesses excellent watersolubility, lubricity and anti-wear property. A preliminarystudy on the anti-wear mechanism of the polymers is performed by means of electron probeand scanning electron microscopy (SEM).     

含环三硅氮烷的星形聚硅氧烷的合成——环硅氮阴离子引发环硅氧烷开环聚合

以环三硅氮锂盐（ＤＮＬｉ３）为引发剂，成功地引发了环硅氧烷开环聚合．通过含氮量测定，利用１Ｈ、２９ＳｉＮＭＲ和ＩＲ谱以及分子量测定（ＧＰＣ）和特性粘度测试，并与模型化合物进行比较，证明所得聚合物是含环三硅氮烷的星形聚硅氧烷．研究了六甲基环三硅氮锂盐引发八甲基环四硅氧烷（Ｄ４）开环聚合的动力学，结果表明该聚合反应相对于Ｄ４为一级反应，同时也比较了不同促进剂对聚合速率的影响，ＤＭＦ对聚合速率的促进作用比ｄｉｇｌｙｍｅ大