电动轿车镁合金副车架的OptiStruct优化设计

使用计算机辅助进行结构分析和优化,在优化软件的协助下,应用镁合金AZ91D,对某燃料电池汽车原副车架进行结构优化和重新设计.对新设计的副车架进行校核,经过分析得出,新副车架在轻量化的同时各项性能都较原件有很大的改善,为燃料电池汽车的进一步轻量化提出了建议.     

A method of etching and powder blasting for microholes on brittle materials

Brittle materials such as semiconductors, ceramics, glasses, piezoelectric etc., are difficult to machine by traditional machining methods. This paper provides an approach to create holes or grooves more efficiently via powder blasting process. Instead of one protective layer for mask that is conventionally used, two layers are coated on the surface of the substrate material. The inner layer is water-soluble resin with excellent adhesion to the substrate but having weak resistance to powder erosion, and the second layer is a photosensitive oligomer that is adhered well to the first layer and has very high resistance to powder erosion. Such a protective coating possesses two contrary characteristics: high resistance to powder blasting and easy removal from substrate after powder erosion. Once the openings of the second layer are formed at the desired positions via a photo-etching method, a printing method, or other methods, the holes or grooves can be obtained by etching through the openings of the second layer to the first layer and the substrate by a powder blasting process. Then the whole protective coating is easily and smoothly stripped off without any damage to the substrate by dissolving the first layer with water. Due to easy removal of the mask plus the good resistance to powder blasting and a much higher erosion rate than the one obtainable by wet and dry etching processes, the proposed process can be applied to create holes or grooves on brittle material, instead of chemical etching process, so as to achieve a good quality and superior rate of production.     

Classification of weld flaws with imbalanced class data

This paper presents research results of our investigation of the imbalanced data problem in the classification of different types of weld flaws, a multi-class classification problem. The one-against-all scheme is adopted to carry out multi-class classification and three algorithms including minimum distance, nearest neighbors, and fuzzy nearest neighbors are employed as the classifiers. The effectiveness of 22 data preprocessing methods for dealing with imbalanced data is evaluated in terms of eight evaluation criteria to determine whether any method would emerge to dominate the others. The test results indicate that: (1) nearest neighbor classifiers outperform the minimum distance classifier; (2) some data preprocessing methods do not improve any criterion and they vary from one classifier to another; (3) the combination of using the AHC_KM data preprocessing method with the 1-NN classifier is the best because they together produce the best performance in six of eight evaluation criteria; and (4) the most difficult weld flaw type to recognize is crack.     

Phase relations in the Al–Pr–Sb system at 773 K

The isothermal section of the phase diagram of the Al–Pr–Sb ternary system at 773 K over the whole concentration region has been investigated mainly by powder X-ray diffraction (XRD) with the aid of scanning electron microscopy (SEM). A new ternary compound Al₁₁Pr₂₄Sb₆₅ has been found.     

甲醇合成气的制取与等压合成创新工艺的发展前景

介绍了甲醇合成工艺的进展，指出现代工业生产采用压力为5MPa的高压造气等压合成甲醇工艺，分析了合成气对甲醇合成的影响。重点阐述了轻烃转化制甲醇合成气的创新工艺——三一段（即外热蒸汽转化、换热转化和自热转化）纯氧转化工艺的特点、原理、工艺流程及主要物耗能耗指标，并与传统工艺进行了对比。举例说明了高压合成气等压合成甲醇技术的推广应用。最后对我国煤炭能源化工综合发展的产品开发和规划框架提出了建议。     

基于电缆地层测试的储层产能预测方法研究

通过对电缆地层压力测试资料和采集流体样品的PVT组分分析,提出了电缆地层测试储层产能预测的方法,为部分替代DST测试提供了理论基础。首先,利用曲线拟合方法精确求取地层有效渗透率和表皮系数等产能参数;利用采集流体样品的PVT组分分析,确定原油黏度、体积系数和溶解气油比等流体参数,结合电缆地层测试的产能方程,从而计算出储层的采油指数(PI)或单层日产量。     

挤压膨化方便粥的工艺优化及品质特性分析

以复合谷物粉为原料，研究挤压方便粥的最佳工艺。基于前期单因素实验结果，通过Box-Behnken Design响应面法优化方便粥的工艺，以理化特性、感官评分、质构特性和蛋白质淀粉的消化率作为考察指标评价挤压方便粥品质。采用傅里叶红外光谱、X-射线衍射研究挤压前、后方便粥的结构。结果表明:挤压方便粥的最佳工艺为:螺杆转速250 r/min，挤压温度170 ℃，加水量19%。验证试验中各变异系数均在0~12%之间，优化后的方便粥工艺条件有良好的重现性且数据可靠。在此工艺条件下，挤压后方便粥蛋白质消化率和淀粉消化率较挤压前分别提高了12.570%和12.602%。傅里叶红外光谱分析表明，挤压前、后的主要官能团结构没有发生明显变化，挤压后部分特征峰强度有所减弱。X-射线衍射扫描分析表明，挤压前、后方便粥的晶体构型发生改变。挤压后方便粥的品质得到提高，微观结构发生了变化。     

第9届亚洲塑料论坛专题报道

简要介绍了在北京召开的第９届亚洲塑料论坛上各国发表的塑料工业国家报告，包括日本、印度、越南、新加坡、泰和菲律宾等６个国家。