Factors Affecting the Relation of Fracture Toughness V_(GC) with Critical Void Growth Ratio R_C/R_O

The relationship between fracture toughness VGC and critical void growth RC/RO was studied for ten kinds of Steel. The macroscopic fracture toughness VGC was determined by using notched tensile specimens. and the microscopic parameters of critical void growth ratio RC/RO were quantitatively measured under SEM. Then, the coefhcient C in the relation VGC = C In(RC/RO) proposed in author's past work was specifically explored. The correlation of C with tensile proderty parameter φ=σyδ/(Eφn) was presented for the Steel investigated, and the effects of low temperature on C were also discussed. Results show that the coefficient C is linearly related to the parameter and insensitive to low temperature.

关于大望远镜卡焦R-C系统视场改正镜设计的研究

研究了大望远镜卡焦R -C系统视场改正透镜的设计。以 2米级口径的望远镜为例 ,卡氏焦点的焦比为F/ 9,采用F/ 3、F/ 2 .5、F/ 2及F/ 1.5四种主镜焦比 ,得到各自的优化结果。其最大像斑尺寸分别为 0″ .2 90 ,0″ .4 18,0″ .934及 1″ .784。研究结果表明 ,卡焦R -C系统视场改正镜设计的难度取决于主镜的焦比 ,主镜焦比在F/ 3左右是很容易设计好的 ,而若小于F/ 2 5 。

高效液相色谱法测定人参单体皂甙的研究──醋酸铵对人参皂甙分离的色谱改性

讨论了醋酸铵对高效液相色谱法（ＨＰＬＣ）分离人参单体皂甙的色谱改性情况，经试验选择采用ＭＰＧ－ＯＤＳ色谱柱，ＵＶ２０４ｎｍ处检测，以乙腈－水－醋酸铵为流动相，在１５分钟内较好地分离了单体皂甙Ｒ＿（ｇ２）、Ｒ＿（ｂ１）、Ｒ＿ｃ、Ｒ＿ｄ、Ｒ＿（ｇ１）、Ｒ＿ｅ等。方法操作简单、快速，可用于人参质量评定的常规分析。