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101.
A methodology for evaluating the reactivity of titanium with mould materials during casting has been developed. Microhardness
profiles and analysis of oxygen contamination have provided an index for evaluation of the reactivity of titanium. Microhardness
profile delineates two distinct regions, one of which is characterised by a low value of hardness which is invariant with
distance. The reaction products are uniformly distributed in the metal in this region. The second is characterised by a sharp
decrease in microhardness with distance from the metal-mould interface. It represents a diffusion zone for solutes that dissolve
into titanium from the mould. The qualitative profiles for contaminants determined by scanning electron probe microanalyser
and secondary ion mass spectroscopy in the as-cast titanium were found to be similar to that of microhardness, implying that
microhardness can be considered as an index of the contamination resulting from metal-mould reaction. 相似文献
102.
节理岩体的代表单元集合体模型及弹性参数预测 总被引:8,自引:0,他引:8
本文明确提出了节理岩体“代表单元集合体”的概念和模型,通过对节理岩体的“代表单元集合体”进行数值模拟,研究了节理岩体的“代表单元集合体”的变形特性,建立了节理岩体的弹性模型,提出了预测节理岩体宏观等效弹性参数的计算机模拟方法,并将其应用于岩体工程稳定性分析中。 相似文献
103.
104.
MODELING LIQUID MASS TRANSFER IN HIGEE SEPARATION PROCESS 总被引:1,自引:0,他引:1
Correspondence concerning this paper should be addressed to Professor Richard S.H. Mah. Hsien-Hsin Tung is now affiliated with Department of Chemical Engineering, California Institute of Technology
Penetration theory is used to describe the liquid mass transfer in Higee separation process. Within a possible range of effective areas, it is shown that the predicted mass transfer coefficients are in reasonable agreement with the estimated mass transfer coefficients. The estimated coefficients were calculated from the experimental data and the possible effective areas. Hence it is concluded the penetration theory is generally applicable to describe liquid mass transfer in Higee separation process. The comparison also suggests that liquid mixing at the junctions of packing materials may be more complete in Higee process than in traditional process. 相似文献
Penetration theory is used to describe the liquid mass transfer in Higee separation process. Within a possible range of effective areas, it is shown that the predicted mass transfer coefficients are in reasonable agreement with the estimated mass transfer coefficients. The estimated coefficients were calculated from the experimental data and the possible effective areas. Hence it is concluded the penetration theory is generally applicable to describe liquid mass transfer in Higee separation process. The comparison also suggests that liquid mixing at the junctions of packing materials may be more complete in Higee process than in traditional process. 相似文献
105.
106.
求得了带有集中质量的分布质量弹性转轴系统横向自由振动的频率方程和振型函数的精确解析表达式,及其与不转动轴系统自由振动的频率方程和振型函数及转动角速度之间的精确解析关系 相似文献
107.
108.
《Drying Technology》2007,25(7):1237-1242
Rewarming of fruits and vegetables after cooling is characterized by heat and mass transfer processes, which leads commonly to condensation of water on the produce surface at temperatures below the dew point. This effect may affect the produce quality due to microbial growth at unfavorable environmental conditions. The amount of condensed water is a function of the produce surface temperature and of the surrounding conditions as air temperature, air humidity, and air flow. Under practical conditions, both the warming and the condensation are strongly affected by the packaging system used. Depending on the flow conditions close to the produce surface, parameters of heat and mass transfer under laboratory conditions were measured. A mathematical model was developed for the determination of the amount of condensed water on fruit surfaces, its reevaporation, and its total dwell time dependent on the environment air conditions. The model describes the heat and mass transfer processes on single fruits. The process of diffusion of humidity in air and proceed of surface temperature is the basis for the model. 相似文献
109.
高分辨率层序地层学克服了岩性地层对比穿时的缺点.高分辨率层序地层对比是等时的高精度的地层对比,它满足了勘探开发中地层对比等时性和高分辨率的要求.测井资料的纵向分辨率较高,是高分辨率层序地层研究的重要资料.提出了利用测井相分析技术,从测井资料上识别出单井岩性和沉积微相剖面,结合测井曲线特征,划分单井基准面旋回,并进行连井地层等时对比,这为定量地进行高分辨率层序地层分析提供了一种方法.通过研究区实际资料的处理,验证了该方法的有效性. 相似文献
110.
一种蒸发式冷凝器的新型设计方法 总被引:3,自引:0,他引:3
蒸发式冷凝器设计方法的粗糙和繁琐限制其广泛应用,特别是限制其应用于民用和小型商用建筑中。针对上述问题,作者通过实验研究了蒸发式冷凝器的影响因素(进风湿球温度、最小截面风速和喷淋水量)对蒸发式冷凝器热质交换的影响。同时提出了一种新型设计方法,此方法简单,精度较高。适合工程设计、选型和生产应用。 相似文献