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LUO De‘an 《地球空间信息科学学报》2001,4(3):15-20
1 IntroductionCadastralmapsandcadastralattributesarethecorecontentsofcadastralinformationmanage ment .SomeofthedevelopedcadastralmanagementsystemsemployGISsoftware (i.e .Mapinfo ,Ar cvieworMaptitudeetc .)tomanagecadastralmapsanduserelationaldatabase (e .g .SQL… 相似文献
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The authors firstly introduce deformation control of deep excavation pit in detail, and then put forward new conceptions such as: effective coefficient of excavation pit, effective area, ineffective area and critical line, and also put forward the referential criteria of deformation control. The System of Optimization Design with Deformation Control of Deep Excavation Pit and Numerical Simulation with Finite Element Method (SDCDEFEM) is also briefly introduced. Factors influencing deformation of excavation pit are analyzed by the system. The measured and simulated data of maximum deformations (settlement, displacement and upheaval) and their positions are analyzed and discussed. The statistic formula estimating maximum deformations and their positions was gained, and economical-effective measures of deformation control were brought forward. 相似文献
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ZHANGYou-kuan KeithSchilling‘ 《地球科学进展》2004,19(3):422-428
The impact of vegetation cover on groundwater table was assessed with the observed water level fluctuations at two monitored wells in stalled on a bare ground and a vegetated land,respectively.Substantial differences in water table behavior were observed under two land cover scenarios.Ingeneral,the water level in the east grass (EG) well was lower and had much less response to rainfall events than the WNG well mainly due to the difference in the land cover.The effect of vegetation was to lower the water level in the EG well through ET and thus reduce groundwater recharge,which in turn reduced the chemical loads to the creek.The daily and accumulative ET
values were estimated with both the Penman-Monteith method and a water table recession model.It is suggested that while the Penman-Monteith method closely modeled hourly ET cycles during the day,it underestimated actual ET during an intensive mid-summer growing period,and especially underestimated actual ET when the water table was close to the landsurface.With the water table recession model,the amount of ET was estimated at its maximum ET of 7.6 mm when the water table was near the groundsurface and then decreases exponentially to zero around day 33 during a dry period with the accumulative ET of 93.9 mm,or 2.84 mm/day.The results from this study clearly demonstrate that landuse and vegetation coverage have significant effects on ET,groundwater recharge and implications for a basin-scale water cycle and chemical loads to rivers and streams. 相似文献
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今年全国高考文综选择题的8~11题和去年全国高考文综选择题的6~8题,两组题考察的均是日照图的微观部分及晨昏线,学生只要掌握日照图中晨昏线与经纬线的特点,及相关的重要数据,再进行图形转换,此类问题便迎刃而解了。 相似文献
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粗粒与剪切结构橄榄岩捕虏体及其单斜辉石微量元素对比 总被引:1,自引:0,他引:1
地山西栖霞具不同结构的“干”灾晶石相橄榄岩进行了全岩化学、微量元素,矿物成分和单斜辉石微量元素分析和对比。表明在橄榄岩从粗粒结构向剪切结构的转化中,随着变质变形作用的增强存在着复杂的熔/流体的加入富集和熔体的提取亏损作用;交代介质属具强渗透性的SiO2不饱和的硅酸盐碳酸岩熔体。同时发现不同结构橄榄岩中单斜辉石的REE与其全岩的REE程度有如下的关系;粗粒结构橄榄岩石中矿物与岩石的差别量大,但REE的配合分形可以反映全岩的情况;剪切结构橄榄岩中两者的差别较小。其它高度不相容微量元素可能主要赋存粒间组分或/和矿物流体包裹体中。 相似文献
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