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地图软件被认为是移动互联网下一个入口级应用.此前,阿里巴巴已投资高德地图,腾讯旗下搜搜近日也上线了搜搜街景地图,再加上谷歌、百度地图,整个地图产业似乎已被互联网巨头抢先占领.不过,在两院院士李德仁看来,当前互联网企业推出的地图软件只是一种可视化地图,是一种无法精准测量的地图,而只有传统的测绘企业在对接了国家测绘地理信息局、国土资源部等政府部门的地理信息后才能为相关部门提供精准的地理信息服务. 相似文献
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在1.5GPa,950℃,恒温101h条件下对华北北缘太古宙地体中的斜长角闪岩块状样品进行了脱水部分熔融实验,实验产物组合为Hb+Cpx+Gt+Gl,获得的熔体为花岗闪长质成分。利用LA-ICP-MS测试了矿物和熔体的微量元素,获得该体系内各矿物/熔体的微量元素分配系数。角闪石、单斜辉石和石榴石的分配系数与前人在类似条件下的实验结果基本一致。这说明无论实验的初始物质是粉末状还是块状,对元素的分配没有太大的影响。各矿物的REE分配系数对离子半径的拟合曲线很好地符合晶格应变弹性模型。整体特征上,角闪石、单斜辉石和石榴石的LILE,LREE分配系数较低,而HREE的分配系数较高,石榴石具有强烈富集HREE的特征。由此,造成实验熔体表现出LILE、LREE富集而HREE亏损的特征。残留相中无金红石,使得熔体中没有明显的Nb、Ta负异常。熔体的主-微量元素特征符合华北北缘中生代埃达克质岩石的基本特征,进一步支持了该类岩石"可能起源于古老下地壳的部分熔融"的成因模式。 相似文献
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Using counties as the basic analysis unit,this study established an evaluation index system for farmland function(FF) from economic,social,and ecological perspectives.The method combining entropy weighting and multiple correlation coefficient weighting was adopted to determine the weights,and the FF indices were calculated for each county.Subsequently,the spatio-temporal characteristics of farmland function evolution(FFE) were analyzed and the coupled relationships between the sub-functions were explored based on a coupling coordination model.At the same time,the dynamic mechanism of FFE was quantitatively analyzed using a spatial econometric regression analysis method.The following major conclusions were drawn:(1) The farmland economic function generally exhibited a declining trend during 1990–2010,and it is essential to point out that it was stronger in underdeveloped and agriculture-dominated counties,while it continuously weakened in developed areas.Farmland social function decreased in 60.29% of the counties,whereas some counties,which were mostly located in north of Zhengzhou and west of Dezhou and Cangzhou,Yantai,and Weihai,clearly increased.A dramatic decline in farmland ecological function occurred around Beijing,Tianjin,and Jinan.Areas located in the northern part of Henan Province and the central part of Shandong Province saw an increase in ecological function.(2) There was a significant spatial difference in the coupling degree and coordination degree of the sub-functions,and the decoupling phenomenon highlighted this.The changes in social function and ecological function lagged behind economic function in developed areas,but these were highly coupled in some underdeveloped areas.(3) FFE in the Huang-Huai-Hai Plain(HHHP) is resulted from the comprehensive effects of regional basic conditions and external driving factors.Furthermore,the transitions of population and industry under urbanization and industrialization played a decisive role in the evolution intensity and direction of farmland sub-systems,including the economy,society,and the ecology.According to the results mentioned above,promoting the transformation from traditional agriculture to modern agricultureshould be regarded as an important engine driving sustainable development in the HHHP.Taking different regional characteristics of FFE into account,differentiated and diversified farmland use and management plans should be implemented from more developed urban areas to underdeveloped traditional agricultural areas. 相似文献