1000MPa级φ7mm(41MnSiV)预应力压痕钢丝的研制

介绍了1000MPa 级φ7mm,41MnSiV 预应力压痕钢丝的成分设计,工艺流程,力学性能和经济效益.41MnsiV 压痕钢丝优于其它国内使用的预应力混凝土构件用冷拔钢材.     

T902抗泡剂结构分析及性能研究

由高分子反应统计理论,结合~1H-NMR及(13)C-NMR方法,分析了T902抗泡剂的序列结构,获得了该三元无规共聚物分子的链段分布函数。系统研究了分子结构对消泡性能的影响,指出了改善抗泡剂配伍性能的正确途径。     

脉冲色谱法测O2在炭分子筛上的吸附与扩散参数

建立了脉冲色谱法测炭分子筛填充柱中气体吸附和扩散参数实验装置。考察了不同载气流速下Ｏ２的脉冲应答曲线，并根据炭分子筛二离散孔结构模型计算出其一级绝对矩和二级中心矩。由一级绝对矩求得Ｏ２在炭分子筛上的吸附平衡常数值为４．９１．由二级中心矩求得Ｏ２在炭分子筛中的大孔扩散系数　Ｄｙ和微孔扩散参数　Ｄｘ／Ｒ２ｘ值分别为１．４６１×　１０－４ｃｍ２·ｓ－１和０．１９６ｓ－１．这种动态下测Ｏ２在炭分子筛上的吸附和扩散参数的方法简便而实用。     

核酸序列的模糊聚类与分子进化

将核酸序列(编码区)分成几类,求出每类的平均信息参数(D_L),用模糊聚类的方法研究它们的相似性和同源性,求出各级相似分岔值并导出动态聚类图.证明了短程相似分岔与序列进化有明显的相性,即L=2-5的一级相似分岔值与物种出现地质年代的对数保持较好的线性关系.     

聚酯工业缩聚过程的微观质量数学模型

介绍了一个工业化聚酯（ＰＥＴ）生产过程中的缩聚模型。模型从聚合反应机理出发,考虑了所有的主反应和主要的副反应,以实测的工艺操作参数为输入,以各反应釜,特别是终端产品的聚工,平均相对分子及相对分子质量分布参数为输出。文章讨论了预缩聚和终缩聚阶段中副产物－－小分子的脱出特点及挥发量的计算,最后介绍了建模方法和模型现场运行结果。     

Triplet repeat disorders: discussion of molecular mechanisms

Comparison of the growing number of disorders known to be associated with triplet repeat expansions reveals both common features and a diversity of molecular pathways. Despite significant progress towards the characterization of proteins coded by the mutant genes, the complex nature of these disorders requires identification of all molecular components of the triplet repeat pathways. In this brief review we will discuss recent progress in determining the molecular mechanisms of disorders with unstable trinucleotide mutations. Received 13 January 1999; received after revision 8 March 1999; accepted 9 March 1999     

Structure and electrical characteristics of Nb-doped SrTiO3 substrates

Strontium titanate (SrTiO3) has been widely used as substrates for growing perovskite oxides thin films be- cause SrTiO3 is chemically and compositionally stable, and has small lattice mismatch with many perovskite oxides[1―3]. It is known that SrTiO3 it…