20#管线钢在役焊接HAZ的组织与性能研究

在役焊接过程中，管内流动介质的快速冷却，易使接头出现氢致裂纹。对20^#管线钢在不同冷却条件和不同焊接线能量下的HAZ的组织性能进行了模拟研究。结果表明，在流动水冷却下，HAZ出现较多的贝氏体、马氏体和MA组元等不平衡组织，使得HAZ的硬度高达330HvN5，性能最差。采用大的线能量焊接，形成较多的上贝氏体和粒状贝氏体组织，对改善接头性能有利。因此，在避免烧穿的前提下增大焊接线能量或减小管内介质的冷却能力，减少高硬度不平衡相的形成，可以降低HAZ氢致开裂敏感性。     

稀土对2Cr13不锈钢夹杂物形态和耐腐蚀性能的影响

设计了不同含量的稀土2Cr13不锈钢,采用扫描电子显微镜观察了不锈钢中稀土夹杂物的形态,并用动电位扫描法对其进行了极化曲线的测试。     

钢—混凝土组合梁的研究与发展

文章对钢—混凝土组合梁的研究和发展进行了分析,并介绍了有关钢—混凝土组合梁的研究方法及值得进一步研究的问题。     

圆钢管混凝土构件在侧向冲击下的动塑性极限弯矩的研究

利用有限元软件ANSYS/DYNA,模拟了悬臂和简支钢管混凝土构件的侧向冲击数值,计算了动塑性极限弯矩。     

一种Cr─Mo─V冷轧辊钢回火工艺参数的研究

利用光学显微镜和电子显微镜对一种Cr－Mo－V冷轧辊钢淬火后的回火组织进行了观察．通过Hollomon关系式建立了该钢回火参数曲线，并在此基础上，建立了等效回方程，为该钢的热处理参数的选择提供必要的理论依据和试验依据．     

纤维双相钢的组织形成及对性能的影响

研究了纤维双相15Mn2Nb钢组织的形成及对性能的影响.结果表明,纤维双相钢具有优异的强塑性匹配,是一种天然的复合材料.其纤维组织的获取主要取决于合金化和热处理工艺规程,而合金元素Nb阻碍铁素体再结晶是形成纤维组织的关键.     

《多绳落地钢井架设计专家系统》软件的实现

本文介绍了面向矿山特种结构工程的一个专家系统，并论述了程序设计的原理、系统的功能，以及与ＡＵＴＯＣＡＤ软件包的接口。     

Purification of platelet-derived endothelial cell growth inhibitor and its characterization as transforming growth factor-β type 1

In 1986, Brown and Clemmons (Proc. natl Acad. Sci. USA83 (1986) 3321) showed that platelets contain a substance, platelet-derived growth inhibitor (PDGI), that inhibits in vitro endothelial cell replication. Although platelets are rich in transforming grwoth factor (TGF-), PDGI was considered not to be related to TGF-, on the basis of its reported properties (extraction from platelets at neutral pH, binding to heparin-Sepharose). However, we purified PDGI to near homogeneity and showed that on the basis of HPLC retention behavior, in vitro growth inhibitory activities with several cell types, receptor binding, and immunoneutralization of growth inhibitory activity with specific anti-TGF- type 1 antibodies, PDGI is most probably identical with TGF- type 1.     

Flow-induced release of adenosine 5′-triphosphate from endothelial cells of the rat mesenteric arterial bed

Adenosine 5-triphosphate (ATP) was released into the perfusate of rat isolated mesenteric arterial beds during each of two consecutive increases in flow. There was no significant difference between the amounts of ATP released on each occasion. Substance P was also released into the perfusate by increased flow, although its release was more variable. Removal of the endothelium of the mesenteric vessels with sodium deoxycholate led to a significant reduction (74%) in the amount of ATP released compared with the release before the endothelium had been removed. This suggests that the ATP released into the mesenteric arterial perfusate during increased flow arises from endothelial cells.     

Determination of erythrocyte pyrimidine 5′-nucleotidase activity by31P nuclear magnetic resonance: Comparison of normal controls and multiple sclerosis patients

Summary A technique to assay erythrocyte pyrimidine 5-nucleotidase activity in situ using³¹P nuclear magnetic resonance spectroscopy is presented. The assay is chemically specific, simple and applicable to untreated lysates. A comparison of enzyme levels in normal controls and in multiple sclerosis patients employing the assay yielded no significant differences between both groups. Difficulties encountered in the quantitative analysis of the assay using¹H-NMR spectroscopy are briefly discussed.