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21.
Yanshanianmagma-tectonic-metalogenicbeltoftheEastChinaisapartofthecircum-Pacificdomain.Alotofpapershavebeenpublishedtodiscuss...  相似文献   
22.
In geochemical logging, the standard capture gamma-ray spectra of Al, Mg, and K have no distinct characteristic energy peaks. This feature easily influences the spectral bands of characteristic peaks of other elements and thus affects the accuracy of calculating their concentrations. To study this influence, we constructed a model formation containing Al, Mg, and K, and employed the Monte Carlo N Particle Transport Code (MCNP) program to simulate their capture spectra. The results indicate that the calculated dry weights of Si are almost free from the influences of Mg, K, and Al. The ones of Ca and Fe are influenced, but only to a minor extent. The dry weight of S is concurrently influenced. Specifically, the K concentration causes S concentration to deviate significantly from its real concentration. By correcting for such influences, we can obtain relatively accurate values. Data processing for a real well validates the finding that Mg, Al, and K in the formation influence the precision of calculation of other elements and also testifies to the effectiveness of the correction method.  相似文献   
23.
????????????????????????????????????????????????SymletС?????????о?????????????????????????????????????, ???????????4???5??????????????????????????????????????2???3????????????????????????????????????????????ε????????????????ο???  相似文献   
24.
A model test system with a dynamic load device for geotechnical engineering in cold regions is presented. This system consists of a model test tank, a refrigeration device and temperature controller, a dynamic load device, together with sensors and data loggers for detecting stress, deformation, and temperature changes. The system can accommodate soil blocks up to 3 m in length, 2.5 m in width, and 1 m in height. The lowest temperature provided by the refrigeration device is -20 °C. The maximum load provided by the dynamic load device is 100 kN and the vibration frequency of the dynamic load can range from 0.1 to 10 Hz. A number of waveforms, such as sine waves, rectangular waves, triangle waves, and other user-defined waves can be generated by the dynamic load device controller.  相似文献   
25.
Adapt系统可以利用脉冲标定波形得到系统的传递函数,它将复杂的传递函数计算过程简化了,用户可以将传递函数的测定作为一种日常工作来做。  相似文献   
26.
将一定范围内的地震数据假设为背景地震和丛集地震的叠加,并同时认为背景地震和丛集地震分别满足不同参数的二维泊松过程.通过引入N阶距离概念,将叠加的二维泊松过程转化为一维的混合密度函数,在对距离阶数进行选择的基础上,最终采用遗传算法进行混合密度分解,以达到提取地震丛集模式的效果.文中将该算法应用于我国西南地区松潘及龙陵主震前丛集地震的提取,并与C值的时间扫描结合,深化了这两次大地震前地震活动图象的认识.   相似文献   
27.
Availability of reliable delineation of urban lands is fundamental to applications such as infrastructure management and urban planning. An accurate semantic segmentation approach can assign each pixel of remotely sensed imagery a reliable ground object class. In this paper, we propose an end-to-end deep learning architecture to perform the pixel-level understanding of high spatial resolution remote sensing images. Both local and global contextual information are considered. The local contexts are learned by the deep residual net, and the multi-scale global contexts are extracted by a pyramid pooling module. These contextual features are concatenated to predict labels for each pixel. In addition, multiple additional losses are proposed to enhance our deep learning network to optimize multi-level features from different resolution images simultaneously. Two public datasets, including Vaihingen and Potsdam datasets, are used to assess the performance of the proposed deep neural network. Comparison with the results from the published state-of-the-art algorithms demonstrates the effectiveness of our approach.  相似文献   
28.
A survey was conducted in an 11-year recovery mobile dune (RMD11) and a 20-year recovery mobile dune (RMD20), in Horqin Sandy Land, Northern China, to determine plant distribution at the mobile dune scale and its relevance to soil properties and topographic features. The results showed that (1) vegetation cover and species number increased from dune top to bottom in the restoration process of mobile dune; (2) the average value of soil organic C, total N, pH, relative height of sampling site, very fine sand content and soil water contents (40−60 and 60−80 cm) of RMD11 were less than that of RMD20, respectively, and there were significant differences (P < 0.05) between the two dunes; (3) soil resources were redistributed by shrub restoration and relative height of sampling site on dune. The distribution of sand pioneer plant, Agriophyllum squarrosum, was positively related to the relative height of sampling site and soil water content, while that of other herbaceous plants was positively related to soil nutrients in the restoration process of mobile dune. These results suggest that at mobile dune scale, plant distributions are determined by a combination of soil properties and topographic feature. Much effort should be made to preserve the interdune lowland and to improve the level of soil nutrients on mobile dune.  相似文献   
29.
本文讨论了河西走廊东部地区早二叠世地层研究的有关问题,认为甘肃山丹青羊泉下二叠统剖面是北祁连山—河西走廊地区的重要代表剖面之一。以该剖面研究为依据,提出走廊东部地区下二叠统的进一步划分方案,分析该区早二叠世地层岩性特征差异的原因,并与走廊西部地区同期地层进行对比,进一步明确了大黄沟组的含意。  相似文献   
30.
青藏高原地区500hPa FGGEⅢb风场订正方法及其分析   总被引:2,自引:1,他引:2  
本文在文献[1]的基础上,用Cressman逐步订正方法,对高原地区500hPa FGGEⅢ_b资料(1979年5—8月每天2次流场图)用我国同期青藏高原气象科学实验资料进行了订正。与天气图(包括科实资料)及科实的流线图对比,发现与天气图等对应得很好,此方法有一定的实用意义。另外,订正图与FGGEⅢ_b流线图比较,主要结果:(1)NCAR软件所绘的流线图能很准确地反应格点风向。(2)FGGEⅢ_b资料能较好地反应高原地区的大尺度环流,但对次天气尺度系统如高、低中心漏分析的很多,尤其是低涡中心,只有1/2的准确率,但它们都对应于正负涡度区。有一点要特别指出:FGGEⅢ_b资料在高原西部常出现很强的低涡,而在订正图上不但涡小,且常只有低槽与之对应。(3)由订正图上可以看到低涡集中出现在高原中部30—35°N的纬带内,而反气旋中心则出现在其北侧(35°N以北)和南侧(30°以南)。(4)在高原的西南及东北边缘地区常出现地形槽,槽线为西北东南走向。它们的形成与地形影响密切,对高原东侧的天气影响也是明显的,值得进一步研究。  相似文献   
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