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11.
A centrifugal mill is a high-power intensity media mill that can be used for ultra-fine grinding, employing centrifugal forces generated by gyration of the axis of the mill tube in a circle. The mill charge motion is quite different depending on the ratio of the gyration diameter to the mill diameter (G / D ratio), varying from a motion similar to that of a conventional tumbling media mill to that of a vibration mill. In this study, a centrifugal mill was constructed with an arrangement where the gyration diameter could be readily adjusted. The batch grinding characteristics of three different minerals (limestone, talc and illite) in water with dispersing agent were investigated at various G / D ratios. It was found that the optimum G / D ratio in terms of the specific energy consumption to give a desired fineness of product was different for the three minerals. This was due to their different reactions to the breakage mechanisms provided by the mill charge motion at varying G / D ratios. The size distributions became progressively narrower at increased grinding times, and particles finer than about 0.1 μm were not detected even for prolonged grinding times. Measurement of specific surface areas indicated that this was not due to an artifact of the size measurements by laser diffractometry. This implies that there is a limitation in which particles finer than 0.1 μm are not produced under the conditions tested in this type of mill, but further investigation is needed for experimental verification of this limit of comminution. 相似文献
12.
Rock fracturing by explosive energy: review of state-of-the-art 总被引:1,自引:0,他引:1
M. R. Saharan H. S. Mitri J. L. Jethwa 《Fragblast: International Journal for Blasting and Fragmentation》2006,10(1):61-81
A study of the dynamic rock fracture initiation and propagation due to explosive energy is presented through a detailed state-of-the-art review. Explosive energy dissipation in crushing and fracturing is examined and the various means to enhance the explosive energy utilization for dynamic rock fracturing are reviewed. The study highlights the need for a better understanding of the dynamic fracturing process particularly in the presence of in situ stresses in the rock mass. 相似文献
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山西沁水盆地煤层气成藏的微观动力能条件研究 总被引:2,自引:4,他引:2
煤层气成藏的微观动力能条件主要包括煤储层的孔隙—裂隙系统、煤储层的生气作用和储气作用两个方面。以山西沁水盆地为例,深入剖析了煤储层的孔隙—裂隙系统及其发育历程、煤储层的生气作用与能量聚散,阐明了煤层气成藏的微观动力能对成藏效应的控制作用。结果表明:构造作用对储层渗透率具有明显的控制作用,成烃增压致使能量聚集,成为盖层突破作用的主要驱动力,而能量放散则主要是通过煤储层孔隙—裂隙系统的产生、发展。根据上述研究成果,沁水盆地煤层气成藏的地质区划结果为:盆地南部的有利区带为阳城和晋城的北部地区,包括潘庄、樊庄、郑庄等地区;盆地中部的有利区带为安泽—沁源地区,位于盆地西斜坡的中南部;盆地北部的可能有利区带为寿阳东南部地区,位于榆次东北部和阳泉西南部之间。 相似文献
15.
Ottavia Corbi 《地震工程与结构动力学》2003,32(2):173-185
In this paper, a control strategy for structural systems is proposed and developed in the frequency domain. The algorithm is substantially based on a linear derivative feedback and a convolution of the control parameter, whose distribution in the frequency field is chosen in such a manner as to comply with the requirements of an ad hoc formulated constrained optimum problem, with the response data monitored until the instant of control action application. Some numerical testing is carried out by referring to given recorded accelerograms, showing a good performance of the proposed approach. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
16.
The climatic impacts of land surface change and carbon management, and the implications for climate-change mitigation policy 总被引:4,自引:0,他引:4
Strategies to mitigate anthropogenic climate change recognize that carbon sequestration in the terrestrial biosphere can reduce the build-up of carbon dioxide in the Earth’s atmosphere. However, climate mitigation policies do not generally incorporate the effects of these changes in the land surface on the surface albedo, the fluxes of sensible and latent heat to the atmosphere, and the distribution of energy within the climate system. Changes in these components of the surface energy budget can affect the local, regional, and global climate. Given the goal of mitigating climate change, it is important to consider all of the effects of changes in terrestrial vegetation and to work toward a better understanding of the full climate system. Acknowledging the importance of land surface change as a component of climate change makes it more challenging to create a system of credits and debits wherein emission or sequestration of carbon in the biosphere is equated with emission of carbon from fossil fuels. Recognition of the complexity of human-caused changes in climate does not, however, weaken the importance of actions that would seek to minimize our disturbance of the Earth’s environmental system and that would reduce societal and ecological vulnerability to environmental change and variability. 相似文献
17.
着重介绍了CuInSe2的结构和光、电学特性;讨论了多各上薄膜沉积技术;评价了主要的合成装置及其作途;综述了制备CuInSe2太阳电池器件的工艺和材料,提出了一种能成功地生产大面积太阳电池薄膜的经济有铲的沉积技术。 相似文献
18.
Measurements of the activation energy of electrical conductance and desiccation rates on subtidal marine algae from Florida
were compared to similar data from the Bay of Fundy, Nova Scotia, on intertidal marine algae frequently subjected to long
periods of exposure to air. We have developed a method for calculating the reaction rate constant of desiccation of fully
hydrated marine algae. Values of activation energies and desiccation rate constants are consistent with the requirements for
survival of these algae under widely different environmental conditions. 相似文献
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