排序方式: 共有39条查询结果,搜索用时 15 毫秒
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图文办公自动化系统的开发策略与实现 总被引:4,自引:2,他引:2
从规划土地管理局业务审批工业的实际,分析了其对图文办公自动化系统的基本需求,提出了将图文办公自动化系统分三部分进行设计的思想,使系统开发简捷、方便,减轻了开发难度,提高了信息管理的安全性。 相似文献
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Adsorption by nanoporous media is critically involved in many fundamental geological and geochemical processes including chemical weathering,element migration and enrichment,environmental pollution,etc.Yet,the adsorption behavior of metal ions on nanoporous materials has not been systematically investigated.In this study,MCM-41 material with a monodisperse pore size(4.4 nm)and a large BET specific surface area(839 m^2/g)was hydrothermally prepared and used as a model silica adsorbent to study the adsorption characteristics of Cu^2+as a representative metal ion.The Cu^2+adsorption capacity was found to increase with increasing suspension pH in the range from 3 to 5 and to decrease in the presence of NaNO3.At 25℃,pH=5,and a solid-to-liquid ratio of 5 g/L,the adsorption capacity was determined to be 0.29 mg/g,which can be converted to a dimensionless partition coefficient of 45,indicating a strong enriching effect of nanoporous silica.The adsorption isotherm and kinetic data were fitted to several commonly used thermodynamic,kinetic,and diffusion models.The adsorption mechanism was also studied by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy and synchrotron-based X-ray absorption spectroscopy.The results suggest that Cu2+ion adsorption is an entropy-driven endothermal process,possibly involving both outer-sphere and inner-sphere complexes. 相似文献
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引入了衡量GIS数字曲线复杂性的四种指标,提出了误差建模中趋势项分离的样条函数法,考察了分离一组具有不同复杂度模拟曲线的有效性,并与差分法进行了比较。 相似文献
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Acta Geochimica - Adsorption by nanoporous media is critically involved in many fundamental geological and geochemical processes including chemical weathering, element migration and enrichment,... 相似文献
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基于语义映射的空间数据转换及其应用研究 总被引:3,自引:0,他引:3
数据转换是GIS工程建设中的一个十分重要的内容,传统的方法往往只是进行数据格式的转换,忽略了空间数据之间的内在联系,本文将语义映射和空间操作相结合,实现空间数据和属性数据的重构,从而实现异构数据的快速转换。 相似文献