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991.
提出了一种基于相对指数熵的地理信息数据分级评价模型,构建级内相对指数熵与级间指数熵指标,分别量化分级数据级别内集聚水平和级别间的离散水平,并利用这两个指标构建了地理信息数据分级的相对指数熵评价指标。在Python中实现地理信息数据分级以及分级的相对指数熵计算。试验中,应用5种常用的分级方法对5种典型分布的6个数据集以及1个人口普查数据集进行分级,并分别计算分级结果的相对指数熵指标。试验结果表明,在面向不同分布的数据集时,相对指数熵指标能够很好地指示出最优分级方法,并且反映出不同分级方法的细小差异,对于地理信息数据分级的评价是有效的。 相似文献
992.
YU Yang YE Qin ZHANG Kexin HE Weihong SONG Bowen XU Yadong KOU Xiaohu WANG Jiaxuan YANG Fengli 《《地质学报》英文版》2020,94(4):942-971
The Cryogenian is a critical period in the history of the Earth. It is marked by multiple extreme climate changes that caused alternating global glacial and interglacial intervals. These dramatically changed the sedimentary system, and metal ores and source rocks distributed widely during this period. Therefore, studying the Cryogenian stratigraphic framework and sedimentary basins is important to improve the stratigraphic resolution for metal mineral and hydrocarbon prospecting and exploration in China. This review paper firstly divides three tectonic-stratigraphic regions in China in the Cryogenian, including the tectonic-stratigraphic regions of Great South China, Xingmeng-Tarim, and North China. Secondly, geochronologic data and geological records are combined to clearly depict the Cryogenian sedimentary sequence of continental blocks and micro-continental blocks in different tectonic-stratigraphic regions. The results were used to propose a new comparison scheme of stratigraphy for the Cryogenian in China. Finally, according to differences of sedimentary evolution and tectonic evolvement, sedimentary basins and their lithofacies paleogeography are identified and summarized, respectively. 相似文献
993.
通用三维GIS场数据模型研究与实践 总被引:1,自引:0,他引:1
随着三维地理信息系统(geographic information system,GIS)应用的发展,空中电磁信号场、空气与水体污染场、地下地质属性场等连续、非匀质的三维空间属性场数据进行建模、可视化与分析计算对GIS基础软件提出了新的挑战。已被广泛应用的TIN(triangulated irregular network)与栅格数据属于表面模型,通常用来表达二维场数据,其中由TIN组成的封闭表面可用于表达三维体,但两者都无法描述非匀质、连续变化的三维属性场。探讨了在通用GIS基础软件中基于TIN和Grid进行升维表达,实现不规则四面体网格(tetrahedralized irregular mesh,TIM)和体元栅格(voxel grid)两大类三维空间场数据模型,分析了两类数据模型的特点,探讨了三维场数据在可视化和分析计算方面的关键技术,实现了基于TIM与体元栅格表达和应用三维GIS场数据,完善了GIS三维数据模型体系,实现了空/天、地表、地下全空间的一体化表达、模拟与分析计算。 相似文献
994.
Comparative study on Co<Subscript>2</Subscript> emissions from different types of alpine meadows during grass exuberance period 总被引:2,自引:1,他引:1
Potentilla fruticosa scrub,Kobresia humilis meadow andKobresia tibetica meadow are widely distributed on the Qinghai-Tibet Plateau. During the grass exuberance period from 3 July to 4 September,
based on close chamber-GC method, a study on CO2 emissions from different treatments was conducted in these meadows at Haibei research station, CAS. Results indicated that
mean CO2 emission rates from various treatments were 672.09±152.37 mgm-2h-1 for FC (grass treatment); 425.41± 191.99 mgm-2h-1 for FJ (grass exclusion treatment); 280.36±174.83 mgm-2h-1 for FL (grass and roots exclusion treatment); 838.95±237.02 mgm-2h-1 for GG (scrub+grass treatment); 528.48±205.67 mgm-2h-1 for GC (grass treatment); 268.97±99.72 mgm-2h-1 for GL (grass and roots exclusion treatment); and 659.20±94.83 mgm-2h-1 for LC (grass treatment), respectively (FC, FJ, FL, GG, GC, GL, LC were the Chinese abbreviation for various treatments).
Furthermore,Kobresia humilis meadow,Potentilla fruticosa scrub meadow andKobresia tibetica meadow differed greatly in average CO2 emission rate of soil-plant system, in the order of GG>FC>LC>GC. Moreover, inKobresia humilis meadow, heterotrophic and autotrophic respiration accounted for 42% and 58% of the total respiration of soil-plant system
respectively, whereas, inPotentilla fruticosa scrub meadow, heterotrophic and autotrophic respiration accounted for 32% and 68% of total system respiration from GG; 49%
and 51% from GC. In addition, root respiration fromKobresia humilis meadow approximated 145 mgCO2m-2h-1, contributed 34% to soil respiration. During the experiment period,Kobresia humilis meadow andPotentilla fruticosa scrub meadow had a net carbon fixation of 111.11 gm-2 and 243.89 gm-2, respectively. Results also showed that soil temperature was the main factor which influenced CO2 emission from alpine meadow ecosystem, significant correlations were found between soil temperature at 5 cm depth and emission
from GG, GC, FC and FJ treatments. In addition, soil moisture may be the inhibitory factor of CO2 emission fromKobresia tibetica meadow, and more detailed analyses should be done in further research. 相似文献
995.
996.
997.
第四纪钻孔基本属性管理系统的AO实现方法研究 总被引:1,自引:0,他引:1
第四纪钻孔与基础地质、水文地质钻孔有所不同,常有更为复杂的测试和实验资料。从第四纪钻孔的基本特征出发,讨论了ArcGIS平台下利用ArcObjects(AO)进行第四纪钻孔属性管理系统的开发,简要说明了系统具有的功能及特色。实践表明,AO具有开发简单、快速、高效、易于扩展等特点,是在ArcGIS上进行相关信息系统研制的有效工具。 相似文献
998.
粘土对丙烯基复合吸水树脂性能的影响研究 总被引:6,自引:0,他引:6
以丙烯酰胺(AM)、丙NN(AA)为原料,以不同粒径的粘士(MMT)为无机填料采用水溶液聚合法合成了复合吸水树脂,讨论了MMT对其吸水性、保水性、韧性、抗温性、抗盐性的影响及其影响机理。结果表明,MMT的粒径越小,吸水树脂吸水倍率越低,韧性、抗盐性、抗温性等性能就越好;可通过调整MMT粒径来提高树脂的综合性能。 相似文献
999.
Analysis on small-earthquake composite fault plane solutions from 1961 to 1999 in Xinfengjiang reservoir area 总被引:2,自引:0,他引:2
Introduction XFJ reservoir has been about 40 years since its water loading in 1959 and has induced a great number of earthquakes. The largest one was the M = 6.1 earthquake occurred on March 19, 1962. Since then, a large amount of seismologists in our country have made many researches on the in-duced earthquake. In the paper, we have studied XFJ reservoir earthquakes and their relation with water cyclic fluctuation by using the mechanism solutions of small earthquakes occurred in these 40 y… 相似文献
1000.