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氧化铝陶瓷表面高度分布状态随抛光时间的变化规律与机理研究
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作者 郭亮龙 董会 +1 位作者 黄姝珂 潘金龙 《热加工工艺》 北大核心 2022年第4期91-94,99,共5页
利用化学机械抛光对氧化铝陶瓷进行加工,结合表面算术平均高度Sa和均方根高度Sq,研究偏斜度Ssk和陡度Sku随抛光时间的变化规律,分析光滑表面形成机理。结果表明:随着抛光时间的延长,Sa和Sq呈先快速下降后缓慢下降的规律;Ssk呈先下降后... 利用化学机械抛光对氧化铝陶瓷进行加工,结合表面算术平均高度Sa和均方根高度Sq,研究偏斜度Ssk和陡度Sku随抛光时间的变化规律,分析光滑表面形成机理。结果表明:随着抛光时间的延长,Sa和Sq呈先快速下降后缓慢下降的规律;Ssk呈先下降后上升再波动的规律;Sku呈先上升后下降再上升的规律。塑性去除、晶粒断裂和晶粒脱落三种作用机理是表面高度分布变化的本质,其中塑性去除作用贯穿整个抛光过程,有利于形成光滑表面;而晶粒断裂和晶粒脱落则主要作用于较光滑表面,这也是Ssk和Sku在抛光后期呈波动变化的主要原因。 展开更多
关键词 氧化铝陶瓷 化学机械抛光 表高度分布 抛光机理
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Locating method of fire source for spontaneous combustion of sulfide ores 被引量:8
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作者 刘辉 吴超 石英 《Journal of Central South University》 SCIE EI CAS 2011年第4期1034-1040,共7页
in order to achieve a more efficient way to accurately detect the position of the fire source of spontaneous combustion underground mine, a simple fire source locating method, based on infrared scanning system which c... in order to achieve a more efficient way to accurately detect the position of the fire source of spontaneous combustion underground mine, a simple fire source locating method, based on infrared scanning system which can determine the point where the highest temperature on the surface of igniting ores occurs, was proposed. First, the differential equations that describe heat flow in ore body were presented and the relationship between the surface temperature distribution and the depth and intensity of inner fire source was established with a relatively simple heat transfer model. With the solution of equation, the expression of the relationship between the surface temperature distribution and the inner fire source was deduced and the mathematical-physical model of heat transfer process was set up. Then, with the model, visualization of fire source on the basis of MATLAB simulation platform was realized. The results show that: 1) within 10 m, when the detecting depth is less than 2 m, the temperature perturbation on ores surface can change rapidly, and then slowly; after 4 m, in contrast, it changes very little, and is even close to zero at 10 m; 2) When it is close to self-ignition duration and the detective depths are 2, 5 and 10 m, respectively, the maximum temperature differences are correspondingly 0.5, 0.04 and 0.005 ℃ in the scope of 1 m×1 m; under the same condition, the maximum temperature differences are 1.391, 0.136 and 0.018 ℃, respectively, in the scope of 2 m×2 m. Therefore, this system can be used to measure the temperature differences on the surface of ore body and determine the highest temperature point directly. Also, it is possible to determine the depth of fire source and its intensity by locating method of fire source indirectly. 展开更多
关键词 sulfide ores spontaneous combustion location of fire source DETECTION
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Research on temperature rise of hoisting machine disk brake
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作者 MA Jun JANG Hai-bo 《Journal of Coal Science & Engineering(China)》 2012年第4期423-427,共5页
A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes duri... A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software. By analyzing the calculation results, the law of tempera- ture change of surface of brake disk and shoes during the braking process was found. The law of brake shoes surface tempera- ture distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s, 1.0 s and 1.5 s was analyzed. A hoisting machine emergent braking test was carried out. Finally, the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface. 展开更多
关键词 hoisting machine disk brake brake shoe temperature distribution finite element method
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IDFT Numerical Simulation Method for Gaussian Rough Surface with Relatively Large Correlation Length
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作者 王廷剑 王黎钦 赵小力 《Transactions of Tianjin University》 EI CAS 2015年第3期216-222,共7页
A numerical simulation method based on inverse discrete Fourier transform(IDFT)is presented for generating Gaussian rough surface with a desired autocorrelation function(ACF). The probability density function of the h... A numerical simulation method based on inverse discrete Fourier transform(IDFT)is presented for generating Gaussian rough surface with a desired autocorrelation function(ACF). The probability density function of the height distribution of the generated Gaussian surface and the root-mean-square height of the rough surface are also considered. It is found that the height distribution of the generated surface follows the Gaussian distribution, the deviation of the root-mean-square height of the modeled rough surface from the desired value is smaller than that of Patir's method, and the autocorrelation function of the modeled surface is also in good agreement with the desired autocorrelation function. Compared with Patir's method, the modeled surface generated by the IDFT method is in better agreement with the desired autocorrelation function, especially when the correlation length is relatively large. 展开更多
关键词 numerical simulation Gaussian rough surface autocorrelation function root-mean-square height IDFT
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