Specification methods for material-handling control algorithms in flexible manufacturing systems

Good methods are needed to specify, test, and debug material-handling control logic. This article surveys a number of representative methods for defining and describing control algorithms for programmable material-handling equipment used in flexible manufacturing systems. The methods are evaluated with regard to their suitability for communication between people and as bases for interfaces to automatic program generators. It is concluded that no single method is entirely satisfactory. Three methods (position diagrams, function block diagrams, and operation networks) have potential to be combined into an effective hybrid approach that minimizes the need for the user to switch between various conceptual models.     

Application of SiC-Si functionally gradient material to thermoelectric energy conversion device

Because of its high–temperature chemical stability, SiC ceramic is a promising material for high-temperature device applications such as thermoelectric energy converters. However, the electrical conductivity of SiC ceramic is too low for it to be used as a thermoelectric energy converter at the cold junction. Therefore, we propose a SiC-Si functionally gradient material (FGM) in order to improve the electrical conductivity of the SiC ceramic at the cold junction. An SiC rod was fired in a temperature gradient furnace. One end of the SiC rod was maintained at 2473 K and the other end was maintained at 1973 K for 30 min. After firing, the porous SiC edge fired at 1973 K was dipped into molten Si in order to infiltrate molten Si into the porous SiC. The microstructure of the FGM is classified into three regions: the SiC-Si composite material; the porous SiC ceramic; and the densified SiC ceramic. The electrical conductivity, the Seebeck coefficient and the thermal conductivity for each region of SiC-Si FGM was measured at 300 K; a figure of merit was calculated. The figure of merit of the SiC-Si FGM at the cold junction, at room temperature, was 10⁸ times higher than that of a nongradient SiC ceramic.     

Thin conducting polypyrrole film on insulating surface and its applications

An electrically conductive plastic material was obtained by the polymerization of pyrrole on insulating polymeric materials and nylon cloth impregnated with the oxidant by vapour phase technique, resulting in a uniform, smooth and adherent coating of conducting polymer having a surface resistance ranging from 200 Ω/□ to 20 kΩ/□, which makes it suitable for applications as an antistatic material.     

我国金属阳极隔膜法烧碱发展现状与对策

详细介绍了我国氯碱工业采用金属阳极隔膜法制烧碱的现状及与世界先进水平的差距。提出了包括大力进行以节能为重点的技术改造；调整烧碱产品规格；彻底淘汰和转换石墨阳极隔膜法；推广先进的扩张金属阳极隔膜电解技术以及结合我国国情有计划地发展离子膜法制烧碱技术等改造措施及预期效果。     

Dynamic buffering performance of the honeycomb paperboard filled with polyurethane

A new kind of composite buffering material was made by filling the voids of honeycomb paperboard with polyurethane. Drop tests were performed to evaluate the dynamic energy absorption capacity of the material. Based on the tests results, we analyzed the mechanical behaviors of the material under different conditions and obtained the inherent influencing laws of some factors on the material＇s dynamic buffering performance. It was shown that the dynamic buffering performance varied directly with impact velocity, and inversely with the void diameter, thickness and buffeting area of the composite material.     

ANALYSIS OF DISSIPATIVE STRUCTURE IN MATERIAL COMMINUTION

ＡＮＡＬＹＳＩＳＯＦＤＩＳＳＩＰＡＴＩＶＥＳＴＲＵＣＴＵＲＥＩＮＭＡＴＥＲＩＡＬ　ＣＯＭＭＩＮＵＴＩＯＮＺｈａｎｇ；Ｚｈｉｔｉｅ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＣｅｎｔｒａｌＳｏｕｔｈＵｎｉｖｅｒｓｉｔｙｏｆＴｅ...     

Physiological and psychophysical responses in handling maximum acceptable weights under different footwear--floor friction conditions

A study on combined manual materials-handling tasks performed on floors under three friction levels was conducted. Eight male subjects participated in the study. The maximum acceptable weight of handling, including lifting, carrying for 3m, lowering, and walking 3m back at twice per minute was determined. The subject then performed the same tasks for 10 min. Heart rate, Vo2, energy efficiency, perceived sense of slip, and rating of perceived exertion for whole body strain were measured. The results showed that the effects of friction level on the maximum acceptable weights of handling, perceived sense of slip, Vo2, and energy efficiency were statistically significant (p相似文献   

纳米SiO2材料的应用

本文根据纳米的奇异特性,简要综述纳米ＳｉＯ２在各个领域中的应用。     

光存储材料CaS∶Eu,Sm的正交实验制备及表征

CaS∶Eu,Sm材料在光存储、光探测领域具有广阔应用前景,但制备过程中影响其发光性能的因素较多,彼此又有交互作用,不易获得最佳工艺参数。本文采用高温固相反应法,通过正交实验设计系统研究了灼烧温度、灼烧时间、稀土掺杂浓度、助溶剂用量对CaS：Eu,Sm发光性能影响的主次关系,经正交分析和验证实验确定了最佳工艺参数应为：Eu∶Sm∶Ca mol%=0.3∶0.3∶99.4%,1100℃灼烧0.5h,助熔剂LiF用量为7%。采用X射线粉末衍射仪、荧光分光光度计（耦合1064nm激光激励源）对样品的物相及发光性能进行了测试与表征。