Effect of pearlitic morphology with varying fineness on the cavitation erosion behavior of eutectoid rail steel

The present work discusses the effect of the pearlitic morphology with varying fineness on the cavitation erosion behavior of eutectoid rail steel. Cavitation erosion of three different types of the pearlitic steels (furnace-cooled, air-cooled, and forced-air-cooled) consisting of coarse, fine, and very fine microstructures were tested in 3.5% NaCl solution and compared with that of the as-received pearlitic rail steel. The variation in the mean depth of erosion (MDE) and mean depth erosion rate (MDER) with erosion time was analyzed. Furthermore, the cavitation erosion resistance of the as-received, the air-cooled, and the forced-air-cooled was found to be 1.03, 1.51, and 2.14 times better than the furnace-cooled pearlitic steel, respectively. It was concluded that the cavitation erosion resistance of the pearlitic steel increased with the increase in the fineness of the microstructure.     

分子距边矢量研究链烃与醛酮的定量构效关系

按碳原子及键合特性分类定义并计算了链烃包括烷、烯,炔,双烯,烯炔烃的分子距离－边数矢量（ＭＤＥ）,将１５３个链烃的ＭＤＥ矢量与相应的沸点相关联,得到良好的线性模型,复相关系数Ｒ＝０．９９７６,均方根误差０．９９７５、ＲＭＳ＝４．７２Ｋ和Ｒ＝０．９９７２、ＲＭＳ＝５．１３Ｋ。结果表明模型具有良好的稳定性和预测能力。进一步对杂原用染色因子进行标识,提出了一种适用于含杂原子体系分子结构描述的ＭＤＥ矢量,     

MOR/SBA-15复合分子筛的合成、表征及其催化性能评价

采用MOR纳米晶和正硅酸四乙酯为硅源,P123三嵌段共聚物为模板剂水热合成MOR/SBA-15复合分子筛催化剂。采用XRD、SEM、TEM和EDX等手段对催化剂进行了表征,在固定床反应器中评价二甲醚制乙醇催化性能。结果表明,通过控制合适的MOR纳米晶种及MOR纳米晶种在SBA-15水热合成体系中的添加量,可以成功地将MOR纳米晶作为SBA-15的结构单元嫁接到SBA-15的介孔骨架中,水热合成的MOR/SBA-15复合分子筛催化剂同时具有MOR和SBA-15的XRD特征衍射峰,相比于SBA-15,其比表面积和总孔体积由756 m2·g~(-1),1.07 cm3·g~(-1)降低至628 m2·g~(-1),0.85 cm3·g~(-1),平均孔径由8.1 nm提高到9.3nm,Cu修饰的MOR/SBA-15复合分子筛催化剂同时具有Cu MOR羰基化和Cu SBA-15加氢的双功能催化性能,其催化剂评价结果显示二甲醚转化率为43.6%左右,乙醇选择性为95.3%,Cu MOR/SBA-15复合分子筛催化剂实现了二甲醚到乙醇的一步转化。     

叶轮机械叶栅多目标多学科设计优化算法

提出了基于多目标寻优的叶轮机械叶栅多学科设计优化算法,方法包括:采用并行多目标差分进化算法作为优化求解器来搜寻叶栅多学科设计优化问题的Paxeto解集,采用非均匀B样条方法对叶片型面进行参数化处理,通过求解Reynolds-Avergaed Navier-Stokes方程评估叶片的气动性能,耦合气动计算得到的叶片表面压力,应用有限元分析方法预测叶片的强度性能.为证明本文方法的实用性,选择叶片的等熵效率和叶片应力为目标函数,完成了NASA Rotor 37转子叶栅的多学科设计优化,结果表明本文提出的多学科设计优化算法具有良好的优化性能.