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31.
郑肇葆 《武汉大学学报(信息科学版)》2003,28(3):272-276
在用遗传算法生成影像纹理分类的“Tuned”模板中,引用了一个新的遗传交叉方法——指派交叉,与其他的交叉方法相比,指派交叉可在相同的搜索空间中提供更好的优化组合。试验证明,指派交叉是值得推广的一种遗传交叉方法。 相似文献
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Abstract. Skeletal sphalerite with stellar, cruciform and snowflake-like (or cauliflower-like) shapes included in pyrite is widely found in the Dajing tin-polymetallic deposit. It occurs only in chalcopyrite-pyrite mineralization stage. The compositions of all sphalerites in the chalcopyrite-pyrite stage are characterized by high Cu content (3.9 - 7.0 wt% with a mean of 5.4 wt%), while the skeletal crystal sphalerite has higher zinc and cadmium contents, and lower copper and iron contents, compared with other sphalerites of the same stage. The skeletal crystal sphalerite in pyrite is possibly generated by exsolution. 相似文献
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From geometry to dynamics of microstructure: using boundary lengths to quantify boundary misorientations and anisotropy 总被引:1,自引:0,他引:1
John Wheeler Z. Jiang D. J. Prior J. Tullis M. R. Drury P. W. Trimby 《Tectonophysics》2003,376(1-2):19-35
The microstructure of a quartzite experimentally deformed and partially recrystallised at 900 °C, 1.2 GPa confining pressure and strain rate 10−6/s was investigated using orientation contrast and electron backscatter diffraction (EBSD). Boundaries between misoriented domains (grains or subgrains) were determined by image analysis of orientation contrast images. In each domain, EBSD measurements gave the complete quartz lattice orientation and enabled calculation of misorientation angles across every domain boundary. Results are analysed in terms of the boundary density, which for any range of misorientations is the boundary length for that range divided by image area. This allows a more direct comparison of misorientation statistics between different parts of a sample than does a treatment in terms of boundary number.The strain in the quartzite sample is heterogeneous. A 100×150 μm low-strain partially recrystallised subarea C was compared with a high-strain completely recrystallised subarea E. The density of high-angle (>10°) boundaries in E is roughly double that in C, reflecting the greater degree of recrystallisation. Low-angle boundaries in C and E are produced by subgrain rotation. In the low-angle range 0–10° boundary densities in both C and E show an exponential decrease with increasing misorientation. The densities scale with exp(−θ/λ) where λ is approximately 2° in C and 1° in E; in other words, E has a comparative dearth of boundaries in the 8–10° range. We explain this dearth in terms of mobile high-angle boundaries sweeping through and consuming low-angle boundaries as the latter increase misorientation through time. In E, the density of high-angle boundaries is larger than in C, so this sweeping would have been more efficient and could explain the relative paucity of 8–10° boundaries.The boundary density can be generalised to a directional property that gives the degree of anisotropy of the boundary network and its preferred orientation. Despite the imposed strain, the analysed samples show that boundaries are not, on average, strongly aligned. This is a function of the strong sinuosity of high-angle boundaries, caused by grain boundary migration. Low-angle boundaries might be expected, on average, to be aligned in relation to imposed strain but this is not found.Boundary densities and their generalisation in terms of directional properties provide objective measures of microstructure. In this study the patterns they show are interpreted in terms of combined subgrain rotation and migration recrystallisation, but it may be that other microstructural processes give distinctive patterns when analysed in this fashion. 相似文献
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安山岩中黄铜矿矿石分析和制硫酸铜工艺的研究 总被引:2,自引:0,他引:2
安山岩中的黄铜矿是庐江中生代陆相火山热液型铜矿床的原生矿,矿石中主要伴生黄铁矿及少量斑铜矿、赤铁矿和褐铁矿。物相分析结果,黄铜矿的粒度很细,只有细磨才能单体解离;它在矿石中分布极不均匀,且与脉石矿物接触疏松,适于粗磨抛尾。物性分析结果,黄铜矿在400~530℃、斑铜矿在450~600℃、黄铁矿在500~680℃氧化分解。实验研究表明,矿石经磨碎磁选,大部分的粗粒级的铁矿物能够回收;粗磨抛尾可获得铜、硫的粗精矿;然后再经硫酸化焙烧、酸浸、过滤、提纯、浓缩结晶可制得工业级硫酸铜。浸渣做炼铁原料,黄钾铁矾做Fe2O3颜料,有时还可回收金、银。 相似文献
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The purpose of this study was to elucidate the floristic and structural characteristics of simple alluvial fan vegetation of southern Sinai and to relate them to environmental variation. The main question addressed was: how does the floristic composition of fan habitats, species richness and life-form vary in relation to environmental change? Thirty-seven alluvial fans, randomly selected in two mainwadis(WadiFeiran andWadiDahab) were analysed quantitively. Two-way Indicator Species Analysis (TWINSPAN) classification and Canonical Correspondence Analysis (CCA) were applied in successive stages of the data analysis to describe vegetational variation in relation to physical gradients. Seven main clusters of fans were defined on the basis of environmental variation. These clusters are divided into three main groups of species richness. Species richness varied along a moisture gradient. The richest fans were the driest habitats, indicating that maximum species richness did not occur at high moisture availability. The moisture gradient is a complex gradient correlated with elevation, slope, climatic aridity, soil texture and the nature of the soil surface. Fine sand, silt plus clay and calcium carbonate showed significant differences between the internal groups and subgroups of the first and second level of the TWINSPAN classification. 相似文献
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从宏观和微观两方面对不同变质程度煤所形成焦炭的结构、构造进行了深入研究。从气煤到肥煤阶段(Ro,m:0.77%~1.16%),焦炭气孔壁厚度逐渐增大;进入焦煤阶段(Ro,m>1.16%),焦炭气孔壁厚度降低。气煤、13焦煤形成的焦炭结构以各向同性体为主,焦煤、肥煤炼出的焦炭以粒状镶嵌结构为主。由气煤和高变质程度的焦煤形成的焦炭,其气孔以微孔和大孔为主,气孔分布标准差Ds最大;肥煤炼出的焦炭,其气孔分布大小较均一;13焦煤和低变质程度的焦煤成焦后,气孔分布状况介于上述二者之间 相似文献
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GE Heping SUN Yan LU Xiancai ZHU Wenbin GUO Jichun LIU Deliang & Chi-yuen Wang . Department of Earth Sciences Nanjing University State Key Laboratory of Mineral Deposit Nanjing China . Department of Earth Space Sciences University of Science Technology of China Hefei China . Department of Geology Geophysics University of California Berkeley CA USA 《中国科学D辑(英文版)》2004,47(3)
In the 1990s of the 20th century, we participated in the research of the stress field in fissure tectonics of scientific deep bore cores for the Deep Observation and Sampling of the Earths Continental Crust (DOSECC for short). Spherical and enriched ul-tra-micro granular textures (nm size), which enriches Nb element (Wang & Sun, 1990; Sun & Wang, 1993)[1,2], were found during the observation of ul-tra-micro slipping lamellae of ductile and brittle oc-curring in Late Mesozoic granites us… 相似文献