Effects of sulfate-reducing bacteria on the corrosion behavior of carbon steel

The influences of the growing process of sulfate-reducing bacteria (SRB) in seawater system on the medium state and corrosion behavior of carbon steel were studied by detecting solution state parameters and using corrosion electrochemical methods. The growing process of SRB in the seawater shows the three stages of growing, death and residual phases. The solution state parameters of the concentration of sulfide, the pH value and the redox potential changed during the three stages of the SRB growing process. And the corrosion rate of D36 carbon steel was accelerated during the growing phase and stable during the death and residual phases. The results indicate that the medium state and the corrosion rate of the steel do not depend on the number of active SRB, but depend on the accumulation of the metabolism products of SRB.     

Dietary fatty acids regulate cholesterol induction of liver CYP7α1 expression and bile acid production

In the present study we investigated the effects of dietary fats containing predominantly PUFA, monounsaturated FA (MUFA), or saturated FA (SFA) on lipid profile and liver cholesterol 7α-hydroxylase (CYP7α1) mRNA expression and bile acid production in C57BL/6J mice. The animals (n=75) were randomly divided into five groups and fed a basic chow diet (AIN-93G) (BC diet), a chow diet with 1g/100g of cholesterol (Chol diet), a chow diet with 1g/100g of cholesterol and 14g/100g of safflower oil (Chol+PUFA diet), a chow diet with 1g/100g of cholesterol and olive oil (Chol+MUFA diet), or a chow diet with 1g/100g of cholesterol and myristic acid (Chol+SFA diet) for 6 wk. The results showed that the Chol+SFA diet decreased CYP7α1 gene expression and bile acid pool size, resulting in increased blood and liver cholesterol levels. Addition of PUFA and MUFA to a 1% cholesterol diet increased the bile acid pool production or bile acid excretion and simultaneously decreased liver cholesterol accumulation despite decreased CYP7α1 mRNA expression. The results indicate that the decreased bile acid pool size induced by the SFA diet is related to inhibition of the liver CYP7α1 gene expression, but an increased bile acid pool size and improved cholesterol homeostasis are disassociated from the liver CYP7α1 gene expression.     

农药残留物的研究现状

从农药残留物的标准和检测方法等几方面介绍了农药残留物的研究现状。     

聚丙烯/超高摩尔质量聚乙烯共混物的结构与性能研究

研究了不同物料比和加工工艺对聚丙烯（PP）／超高摩尔质量聚乙烯（UHMWPE）共混体系性能的影响。结果表明，PP／UHMWPE共混体系具有比音一组分更高的冲击性能，当体系中UHMWPE的质量分数为60％时，共混物的冲击强度高达101kJ/m^2，分别是PP的1．8倍和UHMWPE的1．3倍，将UHMWPE加入PP中可明显降低PP的摩擦系数，提高其耐磨性，而适量UHMWPE加入PP中，对UHMWPE的耐磨性能无不良影响，对以PP为连续相的共混体系，混炼方式对共混物的性能影响大，偏光显微镜分析表明，当PP／UHMWPE共混体系中UHMWPE的质量分数大于40％时，就很难观察到明显的PP大球晶结构，DSC分析显示，PP／UHMWPE共混物出现了两纯组分熔点的结晶熔融峰，PP／UHMWPE为热力学不相容体系。     

岩体结构面对大跨度隧道工程稳定性影响初步研究

基于对沈阳至大连（简称沈大）高速公路扩建工程韩家岭隧道区域调查和分析，研究了岩体结构面对隧道施工过程的影响，围岩失稳方式及可能遇到的问题，并提出了解决这些问题的措施。     

二-(4-羟基丁基)四甲基二硅氧烷的合成研究

采用一步法以二甲基二氯硅烷、四氢呋喃和金属镁粉为原料,在碘乙烷和单质碘催化下合成二-(4-羟基丁基)四甲基二硅氧烷。产物温合物减压过滤,以除去镁盐。滤液无需蒸馏提纯,而直接水解,干燥,减压蒸馏,收集71℃/1333Pa馏份。还探讨和优化合成条件:四氢呋喃与二甲基二氯硅烷之摩尔比应大于3.5;Grignard反应停止后应继续加热回流1小时;蒸馏时系统压力为1333Pa。     

Fitting polynomial surfaces to triangular meshes with Voronoi squared distance minimization

This paper introduces Voronoi squared distance minimization (VSDM), an algorithm that fits a surface to an input mesh. VSDM minimizes an objective function that corresponds to a Voronoi-based approximation of the overall squared distance function between the surface and the input mesh (SDM). This objective function is a generalization of the one minimized by centroidal Voronoi tessellation, and can be minimized by a quasi-Newton solver. VSDM naturally adapts the orientation of the mesh elements to best approximate the input, without estimating any differential quantities. Therefore, it can be applied to triangle soups or surfaces with degenerate triangles, topological noise and sharp features. Applications of fitting quad meshes and polynomial surfaces to input triangular meshes are demonstrated.     

Unipol气相法聚烯烃液体催化剂技术进展

介绍了Unipol气相法聚烯烃工艺液体催化剂的成分、加入反应器的方式和喷嘴结构及控制催化剂液滴尺寸方法等方面的最新进展情况。     

异丁烯两段催化氧化制甲基丙烯酸催化剂研究 Ⅰ．异丁烯气相氧化制甲基丙烯醛多元复合氧化物催化剂的研究

本文报导用于异丁烯（叔丁醇）选择氧化制ＭＡＬ（甲基丙烯醛）的多元复合氧化物催化剂的研究结果。同共沉淀法制备的催化剂的活性主要决定于其化学组成，同时受到制备条件的影响。最佳催化剂的主要物相组成为ＰｂＯ３，Ｂｉ２ＭｏＯ３．３、ＮｉＭｏＯ４、Ｓｂ２Ｏ３及ａ－Ｆｅ２Ｏ３小颗粒。在３５５℃，１０００～２５００ｈ－１空速范围，叔丁醇：水：空气＝１：３．３：７（摩尔比）的条件下可获得异丁烯转化率达９６％，ＭＡＬ选择性达８９％的结果。     

SiO_2对低温液相法制备锐钛型TiO_2/SiO_2纳米复合膜性能的影响

采用浸渍提拉法在玻璃表面制得SiO2/TiO2纳米复合膜,筛选出SiO2∶TiO2优化摩尔比为0.1∶1。结果表明,加入SiO2可有效提高TiO2膜层均匀性,降低晶粒直径,纳米复合膜对甲基橙溶液光催化降解率为38.58%,光照30min后膜接触角为5(°),纳米膜与玻璃之间附着力达到1级,且对各类介质均具有良好的耐蚀性。