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71.
Leaching processes are believed to be responsible for the unusually low-ash content (sometimes less than 1%) of the thick (up to 35 m) Cretaceous coals located in the Greymouth coalfield, South Island, New Zealand. Although leaching of inorganics in peat is a generally accepted process, little is known about leaching after burial. The “Main” and “E” seams in the Greymouth coalfield show good correlation between low ash and bed thickness. The ash content, however, is often less than 1%, which is lower than most known modern analogues (i.e. peat). There are several lines of evidence that suggest that mineral matter may have been removed from the coal not only in the peat stage but also after burial. For example, etching features found in quartz grains and clay aggregates indicate that some leaching processes have taken place. In addition, liptinitic material (e.g., bitumen) in the cleat networks supports the conclusion that there has been some movement of solutions through the coal after burial. These solutions may have helped to remove some of the inorganics originally within the Greymouth coals. 相似文献
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具有弯曲效应的层状结构岩体变形的Cosserat介质分析方法 总被引:13,自引:9,他引:13
在反倾向层状岩体边坡、有底鼓现象的巷道以及隧洞工程中,岩体常出现弯曲变形及弯曲破坏现象。常规的等效连续介质理论忽略了梯度应力的影响,因而不能很好解决上述工程问题.Cosserat介质理论以具有一定尺度的微元体为研究对象,引进了偶应力及弯曲曲率概念,从而考虑了弯曲效应对介质变形特性的影响。本文首先介绍Cosserat介质理论的基本原理,然后建立有限元计算模式,最后通过算例,说明这种模式对计算具有弯曲效应的展状岩体变形问题是有效的。 相似文献
75.
计算极谱法同时测定镉镍的研究 总被引:1,自引:0,他引:1
采用普通极谱仪与计算机联机技术,用卡尔曼滤波处理以KSCN为支持电解质的Cd~(2+)和Ni~(2+)混合溶液的示波极谱重叠波。实验表明,极谱可逆波具有较好的加和性,可采用计算极谱方法对多组分(尤其是难以分开的重叠波)进行同时测定。 相似文献
76.
本文通过对资阳的大~暴雨、暴雨的分布、强度和出现时段等气候统计分析,根据各类天气系统在关键区发生、发展及其演变规律进行分型,并建立了资阳强降水的预报模式. 相似文献
77.
Preliminary study on the relationship between the crust-mantle structure and the formation of Laowangzhai superlarge gold deposit 总被引:2,自引:0,他引:2
The essential shallow-crust structural factors controlling the formation of Laowangzhai gold deposit include favorable tectonic
and regional structural site, the release site of a great deal of the earth energy, favorable orecontrolling structure system,
abundant and favorable source rocks for gold, ductile shearing, abundant minerogenetic materials source in extensive crust
and mantle. And the essential deep-seated crust-mantle structure factors dominating the formation of the ore deposit include
intracrustal low-velocity len, high-velocity bodies in the lower part of middle crust and lower crust, the steps on the slope
of Moho, connecting site of mantle rises, the crust-mantle transition layer, upwelling of asthenosphere and the low-velocity
plume. It is concluded that the fundamental reason that controls the formation of Laowangzhai superlarge gold deposit lies
in the coupling between deep and shallow crust-mantle structure factors controlling the formation of the deposit and their
coupling with the lithospheric evolution and geological event.
Project supported by the National Climbing Plan Programme A-30. 相似文献
78.
Xu Zhongsheng 《岩土力学》1989,10(4):55-65
The use of geosynthetics in every domain of the geotechnical engineering is briefly introduced in this paper. The results and economic benefits obtained at present is also introduced with some engineering examples. 相似文献
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Jiangfeng She Xinchi Li Yaqian Chen Junzhong Tan 《International journal of geographical information science》2019,33(10):2033-2054
Adding building labels greatly improves the recognizability of buildings and the readability of three-dimensional (3D) city scenes. However, building label placement is much more complex in 3D scenes than in two-dimensional (2D) maps. The annotation effect is influenced by the attributes of the 3D label, building visibility, and the spatial relationship between the building and viewpoint. In this context, automatically generating building labels for 3D scenes during interactions requires highly complex computations. By contrast, evaluating candidate labels and then selecting the suitable label for each building can be effectively implemented. This paper introduces an approach for labeling buildings in 3D scenes based on evaluations of label candidates. The proposed method predefines a candidate label set for each building. These candidates are then evaluated in terms of their attributes and the relationship between the labels and viewpoint at runtime. The best candidate label, or a situational alternative for each building, is then placed in order of comprehensive label priority to avoid annotation conflicts. A series of experiments demonstrate that this method effectively enhances the correlation of labels and buildings, improves interactive efficiency, and realizes a viable global label layout. 相似文献