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51.
在土地资源紧缺等"城市病"问题愈发突出的背景下,提高土地集约利用效率是国土资源管理的重点研究方向。为支撑城市土地空间资源集约利用研究,本文在深入研究城市土地利用评价及空间演化模拟技术的基础上,基于C#.NET开发平台,结合ArcGIS Engine组件技术,研发了城市土地空间利用评价预警调控系统,实现土地空间利用评价、预警及政策仿真调控等功能,作为科学管理土地的辅助工具。本文对系统的总体需求、系统结构及主要功能设计与实现进行了阐述,以期为土地资源管理研究及相关软件研发提供参考。 相似文献
52.
Jian Cao Zhijun Jin Wenxuan Hu Yijie Zhang Suping Yao Xulong Wang Yueqian Zhang Yong Tang 《Marine and Petroleum Geology》2010
Calcite veins and cements occur widely in Carboniferous and Permian reservoirs of the Hongche fault zone, northwestern Junggar Basin in northwest China. The calcites were investigated by fluid inclusion and trace-element analyses, providing an improved understanding of the petroleum migration history. It is indicated that the Hongche fault behaved as a migration pathway before the Early Cretaceous, allowing two oil charges to migrate into the hanging-wall, fault-core and footwall reservoirs across the fault. Since the Late Cretaceous, the Hongche fault has been sealed. As a consequence, meteoric water flowed down only into the hanging-wall and fault-core reservoirs. The meteoric-water incursion is likely an important cause for degradation of reservoir oils. In contrast, the footwall reservoirs received gas charge (the third hydrocarbon event) following the Late Cretaceous. This helps explain the distribution of petroleum across the fault. This study provides an example of how a fault may evolve as pathway and seal over time, and how reservoir diagenetic minerals can provide clues to complex petroleum migration histories. 相似文献
53.
根据四川省气象灾害多发、频发的特点,提出四川省气象灾害防御的主要措施和对策,探讨了有关气象灾害防御的保障措施. 相似文献
54.
Yao Bao-an Sheng Chang-jung Zhang Chun-sheng Lin Qing 《Chinese Astronomy and Astrophysics》2004,28(4):399-403
G302 = L3107 is a red star located at the lowest end of the red giant branch of the globular cluster M4. According to its location on the C-M diagram, G302 may be a cluster member. No proper motion or radial velocity determinations are available up to date.
We discovered that C302 is a new variable star with a main period of 1.24719 day and a peak to peak amplitude of about 0.3 mag in V. It may have a second period of 2.38249 day with an amplitude of about 0.05 mag. If it is a cluster member, then there will be interesting implications for the the theory of stellar evolution. 相似文献
55.
Slope aspect has significant effect on the development and distribution of montane forest,especially in arid and semiarid regions.This paper,using SPOT5 images and 1:50,000 DEM,digitally extracts and analyzes the spatial information of montane coniferous forest(mainly Qinghai spruce),and thereby explores how the upper and lower limits and the altitudinal range of coniferous forest vary and how the area of coniferous forest is related with annual insolation with all aspects in the Helan Mountains.The results show that: 1) In the eastern flank,the lower limit of coniferous forest is between 1,600 m and 2,000 m a.s.l.,and the upper limit between 2,800 m and 3,000 m a.s.l.;in the western flank,the lower limit of coniferous forest is between 2,000 m and 2,300 m a.s.l.,and the upper limit between 2,800 m and 3,100 m a.s.l.2) The altitudinal ranges of coniferous forest are 806~1,435 m,438~1,140 m for eastern flank and western flank,respectively.3) The area of coniferous forest takes on a normal distribution with aspect,and it has a close relationship with annual insolation.This distribution model developed in this paper quantitatively reveals the significant effect of slope aspect on the distribution of coniferous forest in arid and semi-arid land. 相似文献
56.
�����Ƚ����Ƶ�ֱ����С������Բ��� 总被引:3,自引:0,他引:3
?????????????????????????????????????????????????????????????????????????伸?β????????????????????????????????????????????????????????????????????????С????????????,??Matlab?????????????????????????????????????????????????????????????????????????????Ч???á??????? 相似文献
57.
为解决海上打桩过程中用全站仪进行圆桩放样问题,通过观测圆桩同一水平面上桩身一点三维坐标和桩侧面切线一个方向,建立切线坐标系统以及椭圆坐标系统模型,并根据观测量之间的相互制约关系,实现圆桩中心坐标的解算.对现场实测数据的计算验证了该算法的所能达到的精度和模型的有效性. 相似文献
58.
Under the special background of China, the cooperative innovation between different government-industry-university-research institutes plays an increasingly important role in the agricultural field. However, the existing literature has paid little attention to it. Considering the cooperation patents, published in the agriculture field stemming from the Full-text Database of China Patents as the study object, the spatial and institutional attribute of the authors as the data source, and by combining the social network and spatial econometrics analysis, this paper analyzes the structure evolution characteristics of cooperative innovation networks of agricultural government-industry-university-research institute in the city level of China in 1985–2014, based on the triple helix theory, with the influence factors discussed. This shows that, 1) since 1985, China's agricultural innovation level has been substantially increased, but the development degree of the cooperative innovation network is low, and the patent cooperation mainly relies on authors in the same unit; 2) enterprises play a leading role in the agricultural cooperative innovation. The effect of the government and hybrid organizations driven by the government is not obvious; 3) the cooperative innovation in the province and city dominates, and a multi-pole pattern has been formed. The cooperative innovation network structure evolves from a single helix empty core and double helix multi core to a double helix hierarchical network; 4) the city's science, education funding and personnel investment are key factors determining the agricultural cooperative innovation, while the agricultural development of the city presents slight negative impacts on it. The spatial mismatch of supply and demand is present in the technical cooperative innovation of China's agriculture. Therefore, the science enhancement and education investment to big agricultural provinces should be promptly implemented. 相似文献
59.
天顶对流层延迟计算方法研究 总被引:1,自引:1,他引:1
依据精密单点定位(PPP)原理编写天顶对流层延迟估计程序,分别利用所编程序和GAMIT软件进行实测数据解算,将所得数据与IGS网站提供数据进行对比分析,结果显示PPP与双差法估计对流层延迟都有较高精度;但在双差法解算过程中发现,无远距离测站参与解算会影响对流层延迟估计的精度。 相似文献
60.
The frequency and extent of debris flows have increased tremendously due to the extreme weather and the Wenchuan earthquake on May 12, 2008. Previous studies focused on the debris flow from gullies damming the mountain streams. In this paper, an equation for the run-out distance of debris flow in the main river is proposed based on the dynamic equation of debris flow at different slopes given by Takahashi. By undertaking field investigations and flume experiments, a new calculation method of the volume of debris flow damming large river is obtained. Using the percolation theory and the renormalization group theory it was deduced that the large particles should comprise more than 50% for forming a stable debris flow dam. Hence, the criteria of damming large river by debris flow is presented in terms of run-out distance and grain composition which was then validated through the event of damming river by debris flow at Gaojia gully, the upper reaches of the Minjiang River, Sichuan, China, on July 3, 2011. 相似文献