钢液对连铸用含碳耐火材料的侵蚀作用研究

采用中频炉的实验室模拟试验(试验条件:钢液温度1600℃,浸入时间30min,气氛分别为空气和真空)和通过对用后耐火材料的显微结构分析,研究了钢液对3种连铸用含碳耐火材料(Al2O3-C、MgO-C和ZrO2-C)的侵蚀作用。结果表明,脱碳层的形成及钢液中夹杂物与脱碳层中耐火氧化物的反应是材料蚀损的主要原因。因此,在含碳耐火材料接触钢液的表面形成致密耐火层,能有效抑制钢液对连铸用含碳耐火材料的侵蚀。     

连续介质模型在边坡渗流分析及疏干工程中的应用

针对露天矿山高边坡地下水渗流场的特点，通过对等效连续介质渗流运动方程中水压力传导系数的剖析和现场疏于工程实践总结，提出了有实用价值的边坡水压流干工程设计方法。     

Enzymatic esterification of glycerol II. Lipase-catalyzed synthesis of regioisomerically pure 1(3)-rac-monoacylglycerols

Regioisomerically pure 1(3)-rac-monoacylglycerols are conveniently prepared in high yields (>75%) and in multigram quantities by enzymatic esterification of glycerol in the presence of various lipases(Chromobacterium viscosum, Rhizopus delemar, Rhizomucor miehei) with a variety of different acyl donors, such as free fatty acids, fatty acid alkyl esters, vinyl esters and triacylglycerols, as well as natural fats and oils. All reactions are carried out in aprotic organic solvents with low water content, namelyn-hexane, diethyl ether, tBuOMe or mixtures of these solvents. Essential for the success of these transformations were the following two factors. First, the creation of an artificial interphase between the solvent-immiscible hydrophilic glycerol and the hydrophobic reaction medium by its adsorption onto a solid support. Second, a facile system for the separation of the desired monoacylglycerol from the reaction mixture, coupled with the continuous recycling of acyl donor and undesirable by-products.     

SLS工艺制造的高分子原型材料选择

面向快速铸造工艺的激光选择性烧结（SLS）工艺制造可以制造可烧蚀的高分子快速原型，结合熔模铸造工艺能够实现金属零件的无模快速铸造。选择既适合激光烧结工艺又满足铸造要求的高分子材料是快速铸造工艺的前提。在系统地比较和分析了常用高分子材料的特性．并进行了粉末激光烧结实验后，选择了聚苯乙烯（PS）材料作为快速铸造用SLS原型的粉末原材料。     

Comparison of YAG: Eu phosphors synthesized by supercritical water in batch and continuous reactors

Luminescent yttrium aluminum garnet (YAG, Y₃Al₅O₁₂) nanoparticles doped with Eu (10 at%) were synthesized in batch-type and continuous-type supercritical water (SCW) reactors. In the case of the continuous-type SCW method, the particles of YAG: Eu phosphors were much smaller and demonstrated a uniform spherical-like shape. Inversely, in the case of the batch-type SCW method, a needle-like or elliptical-like shape was formed because a finite amount of time was required to reach SCW conditions from ambient conditions. However, the emission intensity of YAG: Eu phosphors synthesized by using the batch-type SCW method was stronger. Therefore, it is concluded that the continuous-type SCW method is superior to the batch-type SCW method from the viewpoint of the particle size and shape, but the luminescence property of phosphors in the continuous-type SCW method needs to be improved. In addition, a calcination process slightly improved the luminescence intensities of YAG: Eu phosphors generated by using either the batch-type or continuous-type SCW methods.     

水相酶促酯化法拆分dl－薄荷醇的连续操作

对影响脂肪酶活性、稳定性和对映选择性的因素，如有机溶剂和反应温度等首先进行了优化。其次，使用悬浮于环已烷的粉末状游离脂肪酶（ＣａｎｄｉｄａｃｙｌｉｎｄｒａｃｅａｌｉｐａｓｅＯＦ３６０）作生物催化剂，成功地构建了一个高效的非水相游离酶连续搅拌釜反应器。当使用高度反应性的丙酸酐作为薄荷醇的酰基给体，进行连续的酶促对映选择性酯化反应时，醇的转化率在两周内可保持４０％以上，所生成酯的光学纯度超过９５％ｅ．ｅ。但是，当使用相应的游离丙酸（而不是酸酐）作酰基给体时，薄荷醇的转化率在连续操作开始后迅速下降，表明使用酸酐时的生产力要比使用游离酸时高。最后，对底物溶液的浓度和流速进行了进一步优化；同时对反应器系统的含水量进行了监测，并通过对酸酐料液的浓度或流速进行微调的方法，有效地将有机溶液相的水分浓度控制在一定的范围（２～４ｍｍｏｌ／Ｌ）之内，结果，ｄｌ－薄荷醇对映选择性连续酯化反应非常稳定地运行了两个月之久（转化率４７～３５％，光学纯度９５～９８％ｅ．ｅ．），酶反应器的半衰期超过２００天。     

冗余度机器人扩展雅克比方法的应用研究

采用基于所提出的连续比例因子的梯度投影法,利用模糊推理规则动态求解了多性能指标融合中的权系数,对卫星在轨自维护系统的冗余度机器人推拉帆板作业进行了数值仿真计算。所得到的结果与采用固定比例因子的梯度投影法进行了比较,指出了采用固定比例因子方法的不足之处。实验结果验证了所提出的连续比例因子方法的可行性,为冗余自由度机器人的逆运动学解法提供了新思路。     

铸造CAE技术在航天产品上的应用及发展前景

铸件的凝固过程是一个复杂的高温、动态、瞬时的变化过程,在这个过程中缩孔、疏松等铸造缺陷会相继出现。利用铸造CAE技术可以在生产前发现这些缺陷的具体位置和大小,将质量隐患消灭在计算机模拟的反复比较优化中;并可有效地控制生产成本,提高铸件质量,使铸件获得很高的性价比。通过介绍铸造CAE技术在推动传统铸造向现代铸造发展中发挥的重要作用,以及在北京航星机器制造公司及其它相关企业中的应用情况,阐述了铸造CAE技术在航天产品铸造生产中广阔的应用前景。     

Continuous ethanol production from wood hydrolysate by chemostat and total cell retention culture

Chemostat and total cell retention cultures with internal filter system ofSaecharomyc.es cerevisiae H1-7 were carried out to produce ethanol from wood hydrolysate. Maximum ethanol productivity obtained in a chemostat with the aeration rate of 1 vvm was 3.79 g/(L·h). This was 20% higher than that in a chemostat without aeration. However, the substrate was not completely consumed at the dilution rate with the maximum productivity. The realistic productivity, which has higher than 99% conversion rate of substrate, was. 2.95 g/(L·h). The maximum productivity in the total cell retention culture was 6.65 g/(L·h) at the dilution rate of 0.19 h¹ and the residual glucose concentration was negligible.