电热合金材料的工艺技术研究

电热合金材料的工艺技术是目前重要的研究课题,其中电磁搅拌和稀土强化已经获得实际应用。本文介绍了电磁搅拌技术和稀土强化在电热合金材料制备工艺中的应用、电热合金的选用原则,指出了电热合金材料的质量改进方向。     

Changes during heating in chemical composition and in-vitro digestion of four commodities

The effects of duration of heating on the composition and digestibility of whole cotton seed, almond hulls, whole pressed safflower seed and alfalfa were studied. The four commodities were heated at 125°C from 0 to 120 h. Nitrogen and ash values were relatively stable across commodities and heating times. However, acid detergent fibre, neutral detergent fibre, in-vitro neutral detergent fibre remaining after 48 h fermentation and acid detergent insoluble nitrogen increased hyperbolically, approaching a relatively constant value at long heating times for all commodities. The sensitivity of each commodity to heat damage was different, and the rate that each analysis value approached a relatively constant value differed across commodities. In general, alfalfa was the most sensitive and whole cotton seed the least sensitive for a given nutrient change with heating time. Also the amount of neutral detergent fibre digested approached a relatively constant value at longer heating times for whole cotton seed, whole pressed safflower seed and alfalfa while approaching zero for almond hulls. Prior analysis of an unheated commodity is necessary to utilise compositional analyses to determine heat damage.     

溶剂对助焊剂性能的影响

选用四种不同的醚与单一醇复配作为溶剂配制出四种助焊剂。通过扩展试验、润湿力试验和表面绝缘电阻测试,评价各种助焊剂的性能。结果表明,溶剂种类对焊料的平均扩展率、润湿性能和表面绝缘电阻均有影响;沸点与焊料熔点相近的溶剂所配助焊剂使焊料具有75.4%的平均扩展率;对活化剂有最好溶解能力的溶剂可提高润湿速率约12.5%。     

Microstructure and associated properties of YBCO superconductors prepared by melt-processing techniques

From the standpoint of applications, melt-processed bulk YBa₂Cu₃O_x (YBCO) superconductors are of considerable interest. In this paper, we studied the microstructure and levitation force of melt-processed YBCO, YBCO plus Y₂BaCuO₅, and YBCO+Pt. Large single-crystal samples, grown by a seeding technique, were also studied. The levitation force was highest in melt-processed samples made by the seeding technique.     

Bi-2223/Ag-sheathed tape processing studies

The production of high critical current density J_c Bi-2223/Ag sheathed conductors is a complex process involving interactions among many different parameters. The effects of three factors: 1) powder production path, 2) the first sinter temperature, and 3) the subsequent sinter temperatures were investigated. Statistical methods were used to design the experiment and interpret the results. Transport J_c was the main response for the analysis, but microstructural results were also used to assess the physical basis for the differences in performance. The powder variable had the largest main effect with only very weak main effects for the other factors.     

P18—T200型台式再流焊机的设计特点

全面介绍了Ｐ１８－Ｔ２００型台式再流焊机的结构特征、工作原理及其相关技术指标，并结合再流焊机设计中的关键技术问题，提出了自己的解决方案。     

一种提高油田注汽锅炉热效率方法的可行性研究

油田注汽锅炉热效率普遍偏低，排烟热损失是影响锅炉热效率的主要因素，而排烟热损失决定于排烟温度和排烟量。国内目前对锅炉设备的改造技术多局限于减少锅炉的排烟量上。本文论述了将冷凝技术应用在加热炉上来降低排烟温度，回收利用烟气中水蒸汽的汽化潜热，从而达到提高热效率的方法。     

蒸汽冷凝液低品位热能回收利用途径及效益

利用炼油厂深加工装置产生的蒸汽冷凝液的低温余热作为热动力,驱动溴化锂吸收式制冷系统制冷,建立10℃的冷冻水系统,取代重整装置使用的部分冷却水,使本来只能冷却到40℃左右的工艺气体进一步冷却,提高气液分离效果,从而增加液化石油气的回收率,同时减少压缩机功耗,使蒸汽冷凝液全量回收作锅炉补水,取得了良好的经济效益和环保效果,为南方炼油厂蒸汽冷凝液低品位热能的回收利用开辟了新的途径.     

加氢换热器制造质量控制

加氢换热器是加氢装置关键设备之一,制造过程中质量控制不容忽视,焊接缺陷是最常见的。重大设备制造按要求委托第三方进行监理,设备监理对缺陷的判断处理非常重要。灵活应用各种质量控制工具,分析判断质量缺陷原因,达到控制质量目的。     

Performance review of a novel combined thermoelectric power generation and water desalination system

A novel combined thermoelectric power generation and water desalination system is described with a system schematic. The proposed system utilises low grade thermal energy to heat thermoelectric generators for power generation and water desalination. A theoretical analysis presents the governing equations to estimate the systems performance characteristics combined with experimental validation. Experimental set-up consists of an electric heat source, thermoelectric modules, heat pipes, a heat sink and an evaporator vessel. Four heat pipes are embedded in a heat spreader block to passively cool the bottom side of the thermoelectric cells. The condenser of these four heat pipes is immersed in a pool of saline water stored in an evaporation vessel which is maintained at sub-atmospheric pressure. The liquid to vapour phase change cooling method achieve low saturation temperature and offers a high heat transfer coefficient for the cooling of the thermoelectric generators. At the same time this method utilises the low temperature heat extracted from the cold side of the thermoelectric generator for water desalination. It was observed that at low saturation temperatures greater heat flux could be supplied to the thermoelectric generators with less heat losses to the atmosphere.