山西缺水根源与对策

本文从山西的自然条件、历史发展过程及目前开发等三方面,系统论述了山西缺水之根源,得结论为:自然赐山西一个缺水,历史留山西一个干旱,盲目使干旱加重.解决此问题的根本方法在于开源、节流、治污.     

Why There's Nothing Wrong With Systems Thinking a Little Chaos Won't Fix? A Critique of Modern Systems Theory and the Practice of Organizational Change It Informs

We find ourselves at the dawning of a new millennium, uneasy denizens of a world of growing flux. The models of reality on which we rely in our continuing effort to master the turbulent and hypercompetitive marketplace are failing us. Even the much touted 20th-century innovation referred to by Peter Senge in his 1990 bestseller of the same name as the fifth discipline, that is, systems thinking, turns out to be less than adequate to the task. Therein lies the central purpose of this paper: to demonstrate why there's nothing wrong with systems thinking that a little chaos can't remedy. My intent is twofold: first, to expose the problematic partialness of this paradigm, given its tendency to direct one's focus to not to the whole system, but to its exterior half, and, second, to introduce the reader to Chaos, the powerful cosmology now emerging from 20th-century science, as a science of whole wholes—one that enables the practitioner of management and systems sciences to comprehend the system's externality, its subtle within, and most importantly, the crucial relationship between them.     

The in vitro antiapoptotic effect of dehydroepiandrosterone sulfate in mouse thymocytes and its relation to caspase-3/caspase-6

The effects of dehydroepiandrosterone sulfate (DHEAS) on thymocyte apoptosis induced by dexamethasone (DEX) were investigated. Apoptosis was measured by using agarose gel electrophoresis of DNA, the terminal deoxynucleotidyltransferase (TdT)- mediated dUTP nick end labeling (TUNEL) assay and flow cytometry. Our results showed that preincubation with 1×10⁻⁴ M DHEAS protected thymocytes from DEX-induced apoptosis in vitro. Moreover, we found no blocking effect on the DEX-induced activation of caspase-3 and caspase-6 by the preincubation of thymocytes with DHEAS. This may be interpreted to mean that the antagonism of DHEAS to DEX-induced apoptosis is not related to the activation of these downstream caspases which play a critical role in the execution of apoptosis. Received 25 June 1999; received after revision 1 September 1999; accepted 13 September 1999     

除草剂NC－311中间体2－乙氧羰基氨基－4，6－二甲氧基嘧啶的合成

采用乙氧羰基异硫氰酸酯和，３－丙二酰亚胺二甲酯为原料，乙腈作溶剂，在氮气保护下，控制适当温度，合成了磺酰脲类除草剂中间体－２－乙氧端基氨基－４，６－二甲氧基嘧啶，产率由４５％提高到６５％。还探讨了反应的机理．     

聚苯硫醚与尼龙6共混物的非等温结晶动力学

本文用差示扫描量热法(DSC)研究了聚苯硫醚(PPS)与尼龙6(N6)共混物的非等温结晶动力学,并以四种不同的数据处理方法进行了分析比较。结果表明,随着冷却速率的提高,PPS 及其共混物从熔体开始结晶的温度降低;相同冷却速率下,共混物中的 PPS 的起始结晶温度较纯 PPS 为高。Ozawa 方法及 Harnisch 和 Muschik(H-M)法均能较好地处理该体系的非等温结晶动力学数据,由这两种方法所获得的 Avrami 指数 n 值非常接近。     

介于T_0和T_1之间的拓扑空间

本文主要讨论介于T_0和T_1空间之间的拓扑空间及其性质     

藏红O-高碘酸钾体系催化光度法测痕量锰的研究

本文研究了在pH5.2的NaAc-HAc介质中,痕量锰对高碘酸钾氧化藏红O反应的催化作用,建立了一个测定痕量锰的新方法,线性范围为0-0.4μg/25ml,检出限为1.51×10~(-10)g/ml,并用于铝合金标样,环境水标样中痕量锰的测定.     

自行车交通流基本模型

本文把自行车流的密度，流率及速度三参数按观测法和定义法的不同划分为四种概念体系：断面时段概念，区域时段概念，区域瞬时概念和断面瞬时概念，然后分别论证了各种概念体系下的自行车流基本模型。     

反相离子对高效液相色谱法同时测定药物中维生素B_1,B_2,B_6,B_(12)和PP

采用反相离子对高效液相色谱法同时测定药物中的维生素B_1,B_2,B_6,B_(12),和PP;叶酸在相同条件下也能分离完全。所用的分离柱为μBondapak C_(18);流动相为乙腈,0.01 mol/L磷酸二氢钾和三乙胺(14∶85.5∶0.5(体积比)),内含5 mmol/L十二烷基磺酸钠离子对试剂(简称PIC B_(12))和1.5％氯化钾并以磷酸调pH至2.78～2.82;组分以UV 254 nm检测。回收率为91％～104％,变异系数为1.0％～4.6％。     

胺菊酯中间体3,4,5,6-四氢化邻苯二甲酸酐的气相色谱分析

本文建立了3,4,5,6-四氢化邻苯二甲酸酐的定性定量气相色谱分析,准确度高,重复性好。该分析方法也适用于1,2,3,6-四氢化邻苯二甲酸酐的分析。