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141.
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相比传统手工制图,数字地图制图从产生阶段就展现出了相对的优势,了解传统手工制图向数字地图制图的过渡机制,有助于把握数字地图制图学在信息时代的发展动向。因此,数字地图制图学将如何融合信息时代的众多新技术也是一个值得研究的领域。本文以传统地图制图到数字地图制图再到智能地图制图为主线,分析了数字地图制图学产生的必要性、理论指导、技术支撑和发展新动向,以此探索数字地图制图学的发展趋势。 相似文献
143.
The temporal and spatial variabilities of phytoplankton absorption coefficients (a ph (λ)) and their relationships with physical processes in the northern South China Sea were examined, based on in situ data collected from two cruise surveys during May 14 to 25, 2001 and November 2 to 21, 2002. Significant changes in the surface water in a ph values and B/R ratios (a ph (440)/a ph (675)) were observed in May, which were caused by a phytoplankton bloom on the inner shelf stimulated by a large river plume due... 相似文献
144.
多视匹配MVLL算法及其在ADS40线阵影像中的运用 总被引:1,自引:0,他引:1
基于传统单立体VLL匹配算法,从多视觉立体匹配角度出发,研究了一种新的多视影像匹配MVLL算法。ADS40线阵影像多视匹配试验表明,MVLL算法在相似特征、遮挡特征等难点匹配问题上具有显著优势。 相似文献
145.
Integer aperture ambiguity resolution based on difference test 总被引:1,自引:1,他引:0
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沈阳经济区发展为现代产业基地的定位论证 总被引:1,自引:0,他引:1
国务院从东北老工业基地全面振兴、促进区域经济协调发展出发,适时做出了设立沈阳经济区为国家新型工业化综合配套改革试验区的战略安排,这一举措将使沈阳经济区成为东北老工业基地上升为现代产业基地的核心部分与区域引擎.为此,有必要绘就沈阳经济区的路线图解,阐明沈阳经济区所具备的综合优势,分析沈阳经济区发展为现代产业基地的现实价值,定位现代产业基地的功能,认清建设现代产业基地中遇到的问题,最后创意出科学对策,以求为国家这一重大战略投放提供理论支撑和咨询服务. 相似文献
148.
DAO Kequn CHEN Junlin JIN Peihong DONG Chong YANG Yi XU Xiaohui WU Jingyu XIE Sanping LIN Zhicheng SUN Bainian 《《地质学报》英文版》2013,87(3):690-706
Lindera is a large genus of graceful, pleasantly scented and common native trees and shrubs of southern China and neighboring regions of SE Asia. There is a well-documented Cenozoic fossil record not only in these regions but also from elsewhere. A new fossil leaf record has been found in diatomite beds from the Upper Pliocene Mangbang Formation of Tuantian, Tengchong County, Yunnan. The leaves are identified and assigned to Lindera acuminatissima K. Q. Dao et B. N. Sun sp. nov., by comparing their leaf architecture and epidermal characteristics with those of 51 extant Lauraceae species and with 15 known fossil Lindera taxa. The specimens have well-preserved cuticles, with typical leaf architecture and epidermal characteristics of the Lauraceae, including entire leaf margin, intramarginal veins, basal ternate acrodromous primary veins, one-cell trichome base, paracytic stomatal apparatus, sunken guard cells, subsidiary hardly staining cells and presence of oil cells. These characteristics are consistent with Lindera sect. Daphnidium but are different from reported fossil and extant species of Lindera. The cuticles of Lindera are fragile and delicate with only three Lindera fossils reported based on this tissue. In terms of paleobiogeography, the fossil record indicates that Lindera is distributed in high- to mid-latitude regions of the Late Cretaceous to Paleocene northern hemisphere. Coincidentally, the records of Lindera located on both sides of the Bering Land Bridge possibly support the hypothesis that ancient plants extended via transcontinental exchanges through the Bering Corridor. In the Eocene, ancient Lindera spread to Europe through the Northern Degeer Route and the Southern Thulian Route. At the same time, ancient Lindera spread into Central Asia. Climatic changes and tectonization since the Neogene prevented the propagation of Lindera throughout Asia, North America and Europe, and hence the distribution areas have just regressed to the low-latitude regions in Asia and North America. From the Paleogene to the Neogene, Lindera has changed its distribution by surviving extreme climate changes. Quaternary glaciations ultimately led to Lindera becoming extinct in Europe. The new record from Tengchong, Yunnan, with its lower latitude located in tropical and subtropical regions, indicates that Lindera has lived in those regions since the late Pliocene. 相似文献
149.
水平定向钻进(HofizontNDirecfionl Drilling,简称HDD)是采用安装于地表的钻孔设备。对于大直径管道来说,工程竣工后在钻孔和管道之间要留下300mm-400mm的环状间隙。要对泥浆固结后进行应力应变的分析,前提是要知道环空泥浆的固结时间。而传统测量环空泥浆的固结时间的方法存在着很多问题与缺陷,这也导致了时间检测上面误差较大,从而耽误了研究泥浆固结后受力分析的最佳时间。因此,弄清泥浆固结时间的变化规律非常必要,而目前国内在判定泥浆固结时间的方法上仍处于空白阶段。针对这一状况.本人设计采用两种方法进行固结时间的判定,通过湿度传感器测量环空泥浆间隙的水蒸气含量进行泥浆固结时间的判定。 相似文献
150.