粒子侵蚀下三元乙丙绝热材料炭化层破坏特性实验研究

应用模拟固体火箭发动机烧蚀环境的炭化层制样装置制备三元乙丙绝热材料炭化层,分析了三元乙丙绝热材料炭化层结构特点,并设计了一套粒子侵蚀装置,对侵蚀角度为30°、60°和90°工况进行了三元乙丙绝热材料炭化层的粒子侵蚀破坏试验,应用高速摄影系统记录粒子侵蚀炭化层过程,经过分析计算得出了炭化层的剪切极限强度和抗压极限强度,为...     

The effect of microwave pretreatment on impact breakage of copper ore

It has been shown that very short exposures to a high level of microwave power lead to reductions in ore strength. In this paper, the influence of modulated microwave power on copper ore breakage has been investigated. This approach to power delivery is applied to ascertain whether the strength of porphyry copper ore can be reduced with lower average modulated power levels than using continuous power. Changes in resistance to breakage of the treated and untreated ore were quantified by comparative drop weight tests. Mineralogical investigation for the ore was carried out with the Mineral Liberation Analyser (MLA) for surface identification of minerals and X-ray tomography for volumetric analysis. The comparative drop weight tests showed that material treated for 5 s at 5 kW of modulated power was weaker than untreated material. However, for this particular low grade ore, the degree of breakage which was achieved could be achieved with substantially less mechanical energy. It is possible that by using much higher level of microwave power, better liberation might be achieved than using conventional methods.     

刀体破损检测技术在划片机中的应用

介绍了应用于半导体全自动晶圆划切设备中的刀体破损检测方法,在理论分析与计算的基础上制定检测方案,通过大量数据分析与处理,设计出抗干扰性强的数字滤波器,降低了系统误报率,提高了设备稳定性,保证了划切质量。     

EFFECTS OF DOSING REGIMEN AND AGITATION PROFILE UPON FLOC CHARACTERISTICS

The efficiency of solid-liquid separation processes that employ flocculation and sedimentation mainly depends upon the characteristics of aggregates produced by coagulation. Size and density are foremost, however, most flocculation processes are designed such that many larger floes are formed by floc-floc collisions resulting in the entrapment of large amounts of interstitial water. Thus, as particle size increases, floc density generally decreases. Not only does this affect the achievable rate of sedimentation, but it also contributes to the volume of process sludge that must be dewatered prior to ultimate disposal. The objective of the present work is to examine combinations of flocculant dosing and activation along with shear profile or history that can produce flocs of unusually compact structure, thereby increasing the efficiency of separation and reducing the volume of sludge produced. Four types of batch coagulation experiments were conducted, employing both single and intermittent polymer applications as well as periodic episodes of elevated shear to provide more compact constituent floc structures. A light obscuration method, in which the increase in diode phototube output during sedimentation was used to assess mean aggregate density, was employed throughout the study; it provided a convenient means for comparison of the effects of process modifications upon sedimentation.     

高炉用耐火材料的技术研究

介绍了国内外高炉炉衬的维护与修补方法，并对几种修补方法进行了比较。分析了高炉不同部位炉衬的破损机理，指出，应根据没部位、不同环境进行炉衬设计、耐火材料与泥浆的选择及砌筑。     

增强硬质聚氨酯泡沫塑料的压缩破坏行为

研究了玻纤、玻璃微珠增强材料增强的硬质聚氨酯泡沫塑料在静态压缩下泡孔结构的变化．实验结果表明，两种增强材料其压缩强度和模量都有不同程度的提高，但是其破坏方式则完全不同：玻纤增强的泡沫塑料的破坏方式为泡孔的塌陷和纤维的脱粘，而玻璃微珠增强的泡沫塑料的破坏方式为泡孔结构的破碎和玻璃微珠从基体脱粘或破碎。     

Batch grinding kinetics in the presence of two active zones

It is shown that the presence of two active zones in a grinding mill leads to apparent non-first-order breakage of the top feed size in batch grinding. The equations to describe the kinetics of the breakage of the top size and of the total size distribution are obtained, and an analytical solution is given. Parametric analysis shows the influences of the relative magnitudes of the two active zones, the rates of breakage and the rate of mass transfer between the two active zones on the mill product. The concepts may be applicable to any type of mill where two active zones can exist.     

平面铣削中铣刀状态监控现状的评述

对平面铣削的特点和切削力进行评述,采用一齿周期内的合力平均值(准平均合力),以及力的一次差分方法。评述了刀具破损和磨损的评定指标和评定方法。描述了各种数据处理的方法,特别对人工神经网络的方法进行了描述。     

覆岩离层区积水引发的采场突水机制研究

 通过工程探测和理论分析,就海孜煤矿745工作面巨厚火成岩条件下顶板异常突水事故的机制进行深入研究。研究结果表明：距开采煤层62 m的巨厚火成岩下封闭的离层区积水是引发745工作面异常突水的水源;按传统估算方法计算导水裂隙高度为25.3～36.5 m,不会沟通巨厚火成岩下的离层区积水,但由于离层区积水的载荷传递作用,导致下部2层亚关键层发生复合破断,使得顶板导水裂隙高度异常发育,沟通了离层区积水,这是引发745工作面异常突水事故的原因。突水机制表明,可以通过向积水离层区施工放水钻孔的方法来防治此类突水事故。     

断路器断口闪络保护和断路器失灵保护整定计算

目前,大型发电机变压器组220kV及以上并网断路器的断口闪络保护、大型发电机组故障时的断路器失灵保护普遍存在整定计算不合理的问题,多次导致保护拒动。文中提出较为合理的整定计算方法以及需要注意的一些问题。