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91.
提出了一种用于检测在役车辆车轴产生疲劳裂纹的超声波方法,设计了中心孔探头与斜角探头一起,完成了对车辆车轴的关键区域探伤。 相似文献
92.
冲击式采掘机械工作机构的研究 总被引:3,自引:0,他引:3
目前我国多数采掘机械的工作原理是使岩体产生的压、剪破坏,而冲击式采掘机械则是通过冲击波的传递,在岩体表面产生拉应力,从而使岩体发生拉伸破坏,这里给出了冲击式采掘机械截齿的安装角及冲程的设计方法及计算公式。 相似文献
93.
Certain new sulfide-smelting processes and coal-gasification processes generate high-strength sulfur dioxide streams, for
which a new process for converting sulfur dioxide to elemental sulfur needs to be developed because no process exists that
is generally and economically applicable to the treatment of such streams. A thermodynamic and experimental investigation
to develop a new process for converting sulfur dioxide to elemental sulfur by a cyclic process involving calcium sulfide and
calcium sulfate without generating secondary pollutants was carried out. In this process, the starting raw material, calcium
sulfate, is reduced by a suitable reducing agent, such as hydrogen, to produce calcium sulfide, which is used to reduce sulfur
dioxide to elemental sulfur vapor and calcium sulfate. The latter is, in turn, reduced to regenerate calcium sulfide. In this
Part I, detailed experimental results are presented on the kinetics of the reaction between sulfur dioxide and calcium-sulfide
pellets, which produces elemental sulfur and calcium sulfate. The experiments were carried out at temperatures between 1023
and 1088 K and sulfur-dioxide partial pressures between 9 and 60 kPa by the use of a thermogravimetric analysis (TGA) technique.
The rate of this reaction was demonstrated by the conversion of 40 pct calcium-sulfide pellets obtained from the hydrogen
reduction of fresh calcium sulfate in 10 minutes at 1073 K under a sulfur-dioxide partial pressure of 43 kPa. The reactivity
decreased somewhat during the first three cycles but remained largely unchanged thereafter up to the tenth cycle. This characteristic
of the pellets is important because the solids must be reusable for repeated cycles to avoid generating secondary pollutants.
A pore-blocking model was found to fit the reaction rate. The reaction is first order with respect to sulfur-dioxide partial
pressure and has an activation energy of 101 to 134 kJ/mol (24 to 32 kcal/mol) for calcium-sulfide pellets reacted and regenerated
several different times. Sulfur dioxide-containing streams from certain sources, such as the regenerator off-gas from an integrated-gasification,
combined-cycle, desulfurization unit and new sulfide-smelting plants, contain much higher partial pressures of SO2. In these cases, the rate of the first reaction is expected to be proportionally higher than in the test conditions reported
in this article. The reduction kinetics of calcium-sulfate pellets with hydrogen gas is reported in the accompanying Part
II. 相似文献
94.
高速往复式内燃机平衡轴低质量设计分析 总被引:2,自引:0,他引:2
分析了扇形和偏心圆两种平衡轴设计的要求以及平衡重低质量的设计原则。扇形平衡重半径及宽度应尽量大、夹角应尽量小。偏心圆平衡重的偏心圆半径应尽可能大 ,轴承半径应尽可能小。同样质量的扇形平衡重产生的平衡力比偏心圆平衡重要大。 相似文献
95.
印刷质量控制的基本方法(一)综述 总被引:1,自引:0,他引:1
无论哪一种印刷品的生产都要经过若干个工艺过程,才能将原稿上的图文信息转移到承印物上。由于印刷技术的飞跃发展,标准化和质量控制成为一个很重要的问题。标准化和质量控制在很大程度上是依靠仪器和控制装置来实现的。科学技术的极大发展,大大地推动了印刷技术的发展,印刷所使用的原材料和工艺得到了很大的改进,逐步实现了标准化,提高并稳定了生产高质量产品的能力。目前我们评价印刷品质量的优劣大致有三种方法:主观评价法、客观评价法和综合评价法。主观评价法,是以原稿为基础对照样张来评价。这里有人为的因素,根据评价人的知… 相似文献
96.
叙述了国产的延迟树脂与进口DOWEX-11-A8树脂在腈纶厂NaSCN回收模拟装置上的比较试验,由试验数据可得出;国产的延迟树脂NVI脱除率性能略优于美国DOWEX-11-A8树脂,并可替代DOWEX-11-A8树脂应用于腈纶厂延迟装置中。 相似文献
97.
Microbiological denitrification of red beet juice 总被引:1,自引:0,他引:1
Dorota Walkowiak-Tomczak 《European Food Research and Technology》2002,215(5):401-406
The purpose of study was the determination of optimal conditions for red beet juice denitrification by Paracoccus denitrificans bacteria as well as the evaluation of the usefulness of microbiologically treated juice for the production of a natural colouring preparation for foods. Total reduction of nitrates was found during bacterial culturing at 25 and 30 °C, at an initial pH of 7.0-8.0 and juice osmotic pressure of 900-1100 mOsm/kg. Microbiological denitrification procedure affected colour, taste and aroma of the juice. However, the use of juice as food colouring and component was made feasible by acidification and partial evaporation of water together with volatile substances. 相似文献
98.
99.
George Ter-Stepanian 《Bulletin of Engineering Geology and the Environment》2002,61(3):197-205
The paper discusses the postulated suspension force, by which it is possible to explain some enigmatic phenomena observed
in different types of mass movements. This force is generated in thick suspensions as a result of friction between sinking
solid particles and static water. The suspension force is related to the seepage force but they have opposite directions.
Both forces form flow networks. Having explained the suspension force, the paper describes how this influences the movement
of material, particularly in debris flows. Enigmatic features and the mechanism of debris flows and lahars are explained by
virtue of the suspension force.
Electronic Publication 相似文献
100.
试述法国TECHMETA公司产的CT4型横拼双金属专用真空电子束焊机原理与构造,其中主要阐述电子枪控制电路板的原理。 相似文献