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31.
利用非金属矿制备白炭黑现状及发展前景 总被引:8,自引:0,他引:8
简术了白炭黑的用途和制备方法,综述了利用非金属矿制备白炭黑的方法和技术现状,对充分利用非金属矿制备白炭黑提供思路并展望其发展前景。 相似文献
32.
33.
分析G-R-闵公式后得出,它是从点源幅射场导出的,与地震宏观场不相应。因在近场震源不能视作点源。在分析过程中,导出相当于点源、线源或面源以及复杂源的幅射场的深度公式。对实际的地震,它的源类型一无所知,所以不预作假定,将源指标几何扩散率n作为待定参数,导出了一个物理意义明确而又普遍化的震源深度公式。此公式的诸解法中,以计算方法准确、精度高,作图法有直观的优点,但准确性差、精度低,图算法只作获取粗略值和考察数据均匀性用。计算了9个8级以上巨震、1个71/2大震,和两个M_L=3的有感地震的震源深度,经对比结果很好,利用计算得出震源类型,结合宏观场研究了这些地震的震源几何学。并且首次在国际上给出宏观地震震源深度值的标准误差。 相似文献
34.
基于ACAD的新型地图符号系统 总被引:1,自引:0,他引:1
分析了地图符号和ACAD的特点,设计一套比较完善的、开放的、可扩充的、易于调用且可变比例的地图符号系统NMSS。本文分地图骨架、点、线、面符、注记和曲线光滑6个方面介绍这一系统。 相似文献
35.
茅山山脉东麓的砾岩层位和时代 总被引:1,自引:1,他引:0
通过对茅山东麓砾岩层的实地研究,以5条剖面的岩性、产状和生物等特征为依据,将砾岩分为三类,并分别论述其层位时代。提出了与前人不同的观点。 相似文献
36.
The characteristics of rain and point charges based on routine measurements extending over four rainy seasons are presented. An average rain current density of (1.0±0.1)×10–10 A m–2 and charge per unit volume of rain water of (0.43±0.02)×10–4 C m–3 for the locality are obtained, which are compared with data obtained elsewhere by other workers. The point-discharge current measurements lead to a revised estimate of (0.86±0.08)×10–9 A m–2 for the average point discharge current below storm clouds. 相似文献
37.
J.-Y. Yu 《Environmental Geology》1998,36(3-4):271-276
A few simple mass balance equations were developed to simultaneously estimate how much the pollutants from acid mine drainage
(AMD) in stream water are diluted and removed during their migration. The application of the equations requires knowledge
of the variations in the concentrations of the dissolved pollutants and the stoichiometry of the precipitation reaction of
the pollutants when none of the pollutant shows a conservative behavior along the stream path. The calculation should be restricted
to the pollutants showing much higher concentrations in the polluted main stream water than in the combining or diluting water
of the same target area.
The mass balance equations were applied to estimate the dilution factor and precipitation fractions of pollutants in Imgok
Creek such as Fe, SO4 and Al from the AMD of Yeongdong mine. The results show that the estimation, especially for SO4 and Al, significantly depends on the kinds of the precipitates. When FeOHSO4 and AlOHSO4 are assumed to precipitate, the maximum removal fractions of SO4 and Al by precipitation are respectively 34% and 46% of the original input, which is much higher than the values estimated
when SO4 is considered to be perfectly conservative. It indicates that the stoichiometry of precipitation reaction is very important
in the interpretation of the pollutant dilution and migration and assessment of environmental impacts of AMD. The applicability
of the mass balance equations may still need to be verified. However, examining the calculated dilution factor and precipitation
fractions with the equations can provide invaluable information on not only the behavior but also unexpected input of the
pollutants in the stream water polluted by AMD and other point sources.
Received: 12 November 1997 · Accepted: 30 March 1998 相似文献
38.
??????PPP????????IGS?ο????????????ж??PPP???????????????PPP??ZTD?????????????PPP??ZTD??IGS??????ZTD?ο???????????????PPP???????????????????????30 s????????t???????????????<6 mm???? 相似文献
39.
40.
The development of robust and accurate methods for automatic registration of optical imagery and 3D LiDAR data continues to be a challenge for a variety of applications in photogrammetry, computer vision and remote sensing. This paper proposes a new approach for the registration of optical imagery with LiDAR data based on the theory of Mutual Information (MI), which exploits the statistical dependency between same- and multi-modal datasets to achieve accurate registration. The MI-based similarity measures quantify dependencies between aerial imagery, and both LiDAR intensity data and 3D point cloud data. The needs for specific physical feature correspondences, which are not always attainable in the registration of imagery with 3D point clouds, are avoided. Current methods for registering 2D imagery to 3D point clouds are first reviewed, after which the mutual MI approach is presented. Particular attention is given to adoption of the Normalised Combined Mutual Information (NCMI) approach as a means to produce a similarity measure that exploits the inherently registered LiDAR intensity and point cloud data so as to improve the robustness of registration between optical imagery and LiDAR data. The effectiveness of local versus global similarity measures is also investigated, as are the transformation models involved in the registration process. An experimental program conducted to evaluate MI-based methods for registering aerial imagery to LiDAR data is reported and the results obtained in two areas with differing terrain and land cover, and with aerial imagery of different resolution and LiDAR data with different point density are discussed. These results demonstrate the potential of the MI and especially the CMI methods for registration of imagery and 3D point clouds, and they highlight the feasibility and robustness of the presented MI-based approach to automated registration of multi-sensor, multi-temporal and multi-resolution remote sensing data for a wide range of applications. 相似文献