综合布线系统中通信软件的设计与评价

本文研究了结构化综合布线及网络系统中通信软件设计方案，并对其性能进行了分析评价，通过实际工程的实施，证明所设计的软件程序是切实可行的。     

MICROENVIRONMENTAL EFFECTS OF THE HELICAL CONFORMATIONS OF AMYLOSE AND ITS DERIVATIVES——CATALYTIC EFFECTS OF SODIUM CARBOXYMETHYLAMYLOSE ON THE HYDROLYSIS OF VARIOUS ESTERS OF N-ALKYL-3-HYDROXYPYRIDINIUM IODIDE

Hydrolysis of various carboxylic esters of N-alkyl-3-hydroxypyridinium iodide(2—5) has been studied, both in the absence and in the presence of sodium carboxymethylamylose(NaCMA 1). In the absence of Na-CMA, the hydrolysis of all four substrates follows 2nd-order kinetics when HPO_4~- and CH_3CO_2~- ions are used as the attacking nucleophites. In the presence of 1, however, the course of the reaction depends on the structure of the substrates. For 2 and 3, the observed rate constants k_(obs) are independent of the eoncentration of 1 added, but for those with long hydrocarbon chains, i. e. 4 and 5, the hydrolysis follows MichaelisMenten kinetics. All other experimental results also indicate the formation of supramolecular(incluston) complexes between the Na-CMA host molecules in helical conformations and theesters 4 and 5. In comparison with the bimolecular processes in the bulk phase, the catalytic efficiencies(k_c/K_d) of these supramolecular systems are 3.7×10~4 and 1.7×10~4 times that of the aceta     

简缩性思维

教育部考试中心在对 2 0 0 1年高考试题的分析中指出 :“选择题和填空题主要考查考生能否抓住问题本质 ,以简缩思维解决问题”,又说“思维层次高的学生则能直接抓住问题的实质 ,以简缩的思维解决问题 ,节省了大量时间”.对简缩性思维的研究与培养 ,已成了数学教学中值得重视的新热点 .1　简缩性思维的特征简缩性思维是逻辑思维的简约和浓缩 ,它的主要特点是 :( 1 )洞察性 :高屋建瓴 ,善于抓住问题的本质 ;( 2 )逻辑性 :合乎逻辑思维的规律与法则 ,所得的结果不是空穴来风 ,而是经得起逻辑的检验与推敲 ;( 3)敏捷性 :用最短的时间、最快的速…     

部花青染料与糖淀粉、羧甲基糖淀粉和环糊精包结络合的初步研究

对于糖淀粉(CMA)及环糊精(CD)与各种受物形成的包结络合物,其本质是非极性键合,即受物分子离开极性较大的体相,进入极性较小的宿主内穴,这种体相与内穴中极性的差异在很大程度上决定了宿主-受物包结络合物的稳定性.同时,宿主内穴所提供的低极性微环境也直接影响到内穴中受物的反应性.因此,对宿主内穴特性的研究是非常重要的.Bender曾通过脱酸反应速度的改变测得 CD 内穴的介电常数相当于二氧六环.我们也曾报道用     

PREPARATION OF STRIPE-SHAPED DOMAIN STRUCTURE IN FERROELECTRIC LIQUID CRYSTAL AND THE FABRICATION OF SPATIAL LIGHT MODULATOR

The stripe-shaped domain (SSD) structure was prepared in the initial ferroelectric liquid crystal (FLC) alignment without the application of an external electric field, which was realized by the aligning layer modification through the doping of tin tetra-2, 4-dimethyl phenoxy phthalocyanine (SnPc) into the rubbed polyimide films. Atomic force microscopy was used to investigate the alignment films and the corresponding aligning ability was evaluated through the pre-tilt angle measurement. The memory capability and the contrast ratio of thus aligned SSFLC cells have been enhanced and improved with the appearance of the SSD structure. The electrically controlled 64×64 FLC spatial light modulator was fabricated using the improved ligning method, which proves valuable for the practical device fabrication.     

螺旋构象的微环境效应——羧甲基糖淀粉钠(Na-CMA)对各碘代N-烷基3-羟基吡啶羧酸酯水解的催化效应

本文在存在和不存在羰甲基糖淀粉钠盐(Na-CMA)的条件下对N-烷基吡啶羧酸酯(2—5)的水解进行了研究。在不存在Na-CMA时,以HPO_4~=和CH_3CO_2~-作为亲核试剂,4个受物的水解都遵循二级反应动力学。但当存在Na-CMA时,水解则随受物结构不同而各异,即2和3的水解不受加入Na-CMA浓度多少的影响,但具有长疏水链的受物4和5的表观水解速度常数k_(obs)与Na-CMA浓度的关系符合Michaelis-Menten饱和动力学,各种实验结果表明Na-CMA与受物形成了催化剂——受物的螺旋包结超分子络合物。超分子内催化(k_c/K_d)的效率与相应本体相中以CH_3CO_2~-为亲核试剂之催化碱水解速度常数k_2相比,对受物4和5分别为3.7×10~4和1.7×10~4倍。 活化参数的结果反映出4和5在螺旋内穴中所处地位的差异,对于4的水解,分子内催化是熵有利的,但是对于5则是活化焓项有利。活化自由能的减少与受物包结过程中释放的自由能相近,由此可能提供了通过络合能降低反应活化自由能的一个实例。     

疏水-亲脂作用对反应性的影响 Ⅲ.环糊精对碳氟表面活性剂的熵驱动包结以及亲脂作用对形成糖淀粉型包结物的贡献

用表面张力-浓度曲线法系统地研究了环糊精(CD)和羧甲基糖淀粉钠(Na-CMA)与H(CF_2)_(12)CO_2K(1),Cl(CF_2)_nCH_2CH_2N~+(CH_3)_3I~-[n=8(3),10(5)]和相应的碳氢表面活性剂(24和6)的相互作用。由于几何尺寸的限制,碳氟表面活性剂不能与α-CD形成包结络合物,但3与β-CD形成的包结络合物的稳定性远大于相应的碳氢受物4、3与β-CD的相互作用是熵驱动过程,而C_(12)H_(25)N~+(CH_3)_3I~-(6)则是焓有利的。与具有“预组织化”内穴的CD不同,糖淀粉的包结是与大分子从线团到螺旋构象变化的协同过程,由于缺乏宿主-受物间的亲脂相互作用,Na-CMA不能与所有的碳氟受物形成包结络合物。     

聚合物LB膜定向铁电液晶的特性

利用新近合成的聚酰亚胺LB膜定向铁电液晶分子,通过原子力显微镜对经不同亚胺化温度处理的聚酰亚胺LB膜进行扫描探测,发现相应的LB膜具有不同的形貌结构,认为高温亚胺化的LB膜可以提供较高的势垒,这为铁电液晶双稳记忆性的出现提供了可能,而LB膜的超薄特性有利于开关过程中表面聚积电荷的中和与释放,保证了器件优良的双稳记忆性的最终获得以及微秒量级快速响应的实现。