A new phosphate pretreatment process for adhesive bonding of magnesium AZ31 sheets

An economic, high efficiency sodium dihydric phosphate surface pretreatment process (SDPT) was developed to improve the adhesive bond performance of 2 mm thick hot-rolled wrought magnesium AZ31 sheets. A phosphating solution with sodium dihydric phosphate (NaH₂PO₄), additive sodium fluoride (NaF), and accelerator sodium molybdate (Na₂MoO₄), sodium tungstate (Na₂WO₄) and potassium nitrate (KNO₃) were developed to pretreat the magnesium alloys. The content of sodium dihydric phosphate in the phosphating solution was strictly controlled to insure it supplied sufficient acid radical HPO₄ ^2? to phosphate magnesium AZ31 alloy. Furthermore, a suitable H⁺ content to keep the pH values in the range of 5–6 for a phosphating solution was necessary. With this SDPT pretreatment process, a coating consisting of the magnesium phosphate, magnesia (MgO), magnesium hydroxide (Mg(OH)₂), magnesium fluoride (MgF₂) and a minor amount of molybdenum oxide(MoO₃) was formed on the surface of the magnesium AZ31. While the SDPT pretreated adhesive-bonded joints had better initial bond strength than phosphate–permanganate process pretreated joints, the corrosion resistance of SDPT pretreated joints was slightly inferior.     

中国承包工程企业海外项目融资问题探讨

从项目融资的涵义和特点出发,根据中国承包工程企业海外项目发展现状,探讨了我国承包工程企业海外项目融资的相关问题和几种方式.     

Pyrolysis of Polyethylene over Aluminum-Incorporated MCM-41 Catalyst

Aluminum-containing MCM-41 catalysts were synthesized in this study by impregnation of aluminum into hydrothermally synthesized MCM-41. Aluminum was loaded into the porous framework of silica with different Al/Si ratios, using aluminum isopropoxide as the aluminum source. These catalysts exhibited Type IV adsorption–desorption isotherms and had a pore diameter of 2.4 nm. Aluminum species were coordinated tetra- and octahedrally in the structure of catalysts. Diffuse Reflectance Fourier Transform Infrared Spectra (DRIFTS) analysis of the pyridine-adsorbed catalysts revealed the existence of Brönsted acid sites in the synthesized catalysts in addition to the Lewis acid sites. The performance of these catalysts was tested in the degradation of polyethylene using a thermogravimetric analyzer. Pure MCM-41 did not show a significant reduction in the degradation temperature of polyethylene, whereas aluminum-impregnated catalysts were successful in decreasing the temperature.     

深水浊积复合水道砂体内部建筑结构随机模拟——基于多点地质统计学与软概率属性协同约束方法

结合地质认识将研究区深水浊积复合水道细分为主水道、水道侧缘、天然堤和侧积泥等4类建筑结构要素,应用多点地质统计学与软概率属性协同约束方法随机模拟得到了深水浊积复合水道砂体内部建筑结构,在此基础上对建筑结构要素控制下的储层物性进行了模拟。结果表明,多点地质统计学与软概率属性协同约束方法所得随机模拟结果较好地体现了深水浊积复合水道的空间结构、几何形态以及物性分布特征,可以为油田后期层内挖潜剩余油提供参考依据。     

Preparation and characterization of molecularly imprinted polymer of bovine serum albumin

Molecularly imprinted polymer beads of bovine serum albumin (BSA) were prepared via inverse phase suspension polymerization, using BSA as the template molecule, a combination of acrylamide and methacrylic acid (MAA) as double functional monomers, and N, N′‐methylene bisacrylamide as the crosslinker. The effect of different monomer ratios and degrees of crosslinking were investigated. When both selectivity and physical properties of the resultant polymer beads were taken into account, the ratio of MAA in the total monomers was chosen at 40% (m/m) and the degree of crosslinking at 30% (n/n), the resultant polymer beads had good selectivity (α = 2.77) and good physical properties. The effects of pH and temperature were studied. It turned out that the functionalization of polymers of BSA prepared via inverse‐phase suspension polymerization exhibited specific recognition for BSA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

铝基覆铜板导热系数的测试方法

介绍了铝基覆铜板导热系数的测试现状,综述了固体规则试件的导热系数测试方法,并对其优缺点以及用于铝基覆铜板导热系数测试的可行性进行了分析。     

利用焦化厂焦油渣配煤炼焦的工艺研究

根据邯钢目前焦油渣的产量、处理方式以及废渣特性,在小焦炉进行了配煤炼焦试验。试验结果表明:添加适当比例的焦油渣对炼出的焦炭质量影响不大,配煤炼焦是可行的,添加1%焦油渣效果最好,可以合理有效地解决焦油渣造成的环境污染问题,同时还能创造一定的经济效益。