钢筋混凝土静力等效简化模型的数值模拟

钢筋混凝土是由钢筋和混凝土构成的复合材料,属于非均质、非线性材料.在数值分析中要分别采用不同材料、单元类型模拟(即建立分离模型),这种模拟方式计算量过大,不适于对其整体结构进行分析.通过抗弯刚度等效的简化方式,建立了钢筋混凝土的均质等效模型,借助有限元软件对所建均质模型和分离模型进行了线性、非线性的静力模拟,由对结果的比较,确定简化模型的材料参数,为钢筋混凝土结构的静力模拟分析奠定基础.     

STUDY ON RESIDUES OF ~（14）C－FENITROTHION IN MODEL RICE－FISH ECOSYSTEM AND FIELD RICE－FISH ECOSYSTEM

ＳＴＵＤＹＯＮＲＥＳＩＤＵＥＳＯＦ~（１４）Ｃ－ＦＥＮＩＴＲＯＴＨＩＯＮＩＮＭＯＤＥＬＲＩＣＥ－ＦＩＳＨＥＣＯＳＹＳＴＥＭＡＮＤＦＩＥＬＤＲＩＣＥ－ＦＩＳＨＥＣＯＳＹＳＴＥＭＺｈａｎｇＺｈｏｎｇｌｉａｎｇ（张仲良）；ＷａｎｇＨｕａｘｉｎ（王化新）；Ｇ?..     

螺杆泵在原油集输中的应用

油田原油集输中常用的泵类主要是离心泵。随着技术的发展,螺杆泵作为新的集输泵类,开始越来越多的被广泛应用,螺杆泵是利用螺杆的回转来吸排液体的,它是容积泵的一种。螺杆泵已在一些油田成功使用,它具有良好的变速调节性,可以通过高压变频器调节转速,利用转速的变化调节外输流量,既可以满足工艺需要,也可以达到节能的效果。     

STUDY ON RESIDUES OF ~(14)C-CARBOFURAN IN MODEL RICE-FISH ECOSYSTEM

Residues of 14C- carbofuran were studied in model late- rice ecosystem (LRE) and early- rice ecosystem (ERE). The treatment consisted of two rates of the pesticide (1x) and 2.5x). At day 56 after application, 7.3% (1x) and 2.9% (2.5x) of the pesticide and its degradative products remained in the water of the LRE, and 1.8% (1x) and 2.4% (2.5x) of them remained in the water of the ERE. At harvest, 37.5% (LRE) and 24.0% (ERE) of the pesticide applied were detected in the upper layer of the soil; and 40.6% (LRE) and 26.9% (ERE) remained in the lower layer of the soil. The residues in the rice plants increased at the first stage, reached maximum levels during day 14 to 28 after application, and decreased thereafter. At harvest, residues in the stems and leaves in the two treatments (1x and 2.5x) were 3.91μ g/g and 7.78μ g/g (LRE) and 5.04 μg/g and 17.29 μ g/g (ERE) respectively. Residues in the ears were about 1/8 to 1/12 of that in the other parts of the plants. The pesticide residues in fish bodies in both experiments were also determined.