积石峡水电站溢洪道堰闸段工程中锚索测力计的应用

文章简述了积石峡水电站溢洪道堰闸段锚索测力计的设计布置、率定检验、安装方法及张拉过程中对测力计的观测等方面,以加强锚索测力计在锚索张拉施工过程中的质量控制。     

基于正交设计的黄池沟退水道弯道体型优化的数值模拟分析

为探求黄池沟退水道弯道的合理体型,采用正交设计与数值模拟相结合的方法研究了体型参数对弯道水流的影响。选取弯道宽度、弯道曲率半径、纵向坡度3个主要影响参数按正交试验设计,确定了9组正交试验方案,利用经水工模型试验结果验证的数学模型对正交试验方案进行模拟,分析了体型参数对弯道及下游陡坡段横向水位差的影响。结果表明,3个体型参数影响作用由大到小依次为纵向坡度、弯道宽度和弯道曲率半径;坡度为显著影响因素,且平坡最佳,弯道曲率半径和弯道宽度影响不显著,据此推荐合理体型参数为坡度取0,弯道宽度和弯道曲率半径采用原设计值。     

Quantitative in Situ Measurement of Ion Transport in Polypyrrole/Poly(styrenesulfonate) Films Using Rotating Ring-Disk Voltammetry

An approach based on rotating ring-disk electrode (RRDE) voltammetry is described for the quantitative, in situ measurement of ion transport between solution and conducting polymer films. The specific composite film studied in this report is polypyrrole/poly(styrenesulfonate) (pPy(+)/pSS(-)). Cation flux in and out of the polymer was obtained from the mass-transport-limited reduction current for the dopant cation(s) measured at the ring during redox cycling of the polymer. Crucial to this method is the use of a supporting electrolyte that is sterically inhibited from passing into the film and the use of dopant ions that adhere to specific electrochemical constraints. With this method it was possible to quantitatively account for all changes in charge compensation in the film by the specific cation(s) involved. Three different cations were explored alone and in paired combinations. Solutions containing mixtures of dopant cations were studied to determine whether the pPy(+)/pSS(-) films exhibit preferential doping. Kinetic factors, likely due to steric differences in the dopant cations, were found to lead to significant preferential doping of the polymer.     

Synthesis and in vitro antimalarial activity of sulfone endoperoxides

A series of 4,8-dimethyl-4-phenylsulfonylmethyl-2,3-dioxabicyclo[3.3.1]+ ++nonanes, carrying a variety of substituents at position-8 (4) were prepared by a short and efficient method from R-(+)-limonene. Key reactions include thiol oxygen cooxidation, and alkylation and acylation of a sterically hindered tertiary alcohol compatible with the endoperoxy functionality. Some of compounds 4, which are structurally related to yingzhaosu A (2), were found to exhibit in vitro antimalarial activity comparable to that of artemisinin (1) and superior to that of arteflene (3).     

Cost Saving by Heat Recovery. 1 – Stenters

From Mr T A Weaver Sir, I read with interest the above publication [J. S. D. C., 96 (June 1980) 305], and feel that observations arising from our own experience in supplying stenters over a number of years may be appropriate.     

General method for plasmid construction using homologous recombination

We describe a general method for plasmid assembly that uses yeast and extends beyond yeast-specific research applications. This technology exploits the homologous recombination, double-stranded break repair pathway in Saccharomyces cerevisiae to join DNA fragments. Synthetic, double-stranded "recombination linkers" were used to "subclone" a DNA fragment into a plasmid with > 80% efficiency. Quantitative data on the influence of DNA concentration and overlap length on the efficiency of recombination are presented. Using a simple procedure, plasmids were shuttled from yeast into E. coli for subsequent screening and large-scale plasmid preps. This simple method for plasmid construction has several advantages. (i) It bypasses the need for extensive PCR amplification and for purification, modification and/or ligation techniques routinely used for plasmid constructions. (ii) The method does not rely on available restriction sites, thus fragment and vector DNA can be joined within any DNA sequence. This enables the use of multifunctional cloning vectors for protein expression in mammalian cells, other yeast species, E. coli and other expression systems as discussed. (iii) Finally, the technology exploits yeast strains, plasmids and microbial techniques that are inexpensive and readily available.     

含有零值和负值的随机准备金模型

在准备金评估中,由于多数随机准备金模型基本假设的限制是不能直接处理含有零值和负值增量赔款三角形,本文利用一个变换和广义线性模型的混合模型去解决这种情况．     

鄂尔多斯盆地高自然伽马异常特征

为了加深对盆地深部和浅部高自然伽马异常特征综合分析研究,揭示高自然伽马异常地质成因,从而 促进盆地多种能源矿产协同开发研究,针对收集大量的地球物理测井资料、地质资料及其他相关成果,绘制并分 析了相关成果图。研究中遵循从单孔测井曲线特征分析到典型剖面研究,并按层对高自然伽马的平面分布特征 进行分析研究。化验测试结果和自然伽马能谱测井成果研究表明,在本区,自然伽马异常增大主要是由于铀的 活化和聚集,导致铀元素增加而引起。相关研究表明,盆地深部和浅部的铀异常具有一定的关系,盆地历经的沉 积环境变迁是铀元素富集的主导因素。     

混凝土坝裂缝变形的不确定性分析模型

混凝土坝裂缝的发生和发展受到不确定因素影响。将大坝系统及其安全监控看作一个受诸多因素影响的不确定性系统,结合裂缝实测资料,应用近似推理模型和信息分配法,建立了裂缝变形的不确定性分析模型。