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51.
There are more than 600 Cenozoic volcanic cones and craters with abeut 50 000 km2of lava flows in northeast China, which formed many volcanic clusters and shown the features of the continental rift - type volcanoes. Most volcanic activities in this area, especially in the east part of Songliao graben, were usually controlled by rifts and faults with the main direction of NE / NNE in parallel and become younger from the central graben towards its both sides, especially to the east continental margin. It is revealed that the volcanism occurred in northeast China was as strong as that occurred in Japan during the Miocene and the Quaternary. The Quaternary basalt that is usually distributed along river valley is called "valley basalt"while Neogene basalt usually distributed in the top of mounts is called "high position basalt". These volcanoes and volcanic rocks are usually composed of alkaline basalts with ultramafic inclusions, except Changbaishan volcano that is built by trachyte and pantellerite. 相似文献
52.
为了给公路设计部门提供选线依据,运用瞬变电磁法在山西境内的某两条高速公路隧道工程设计线路段上进行探测,以查明下覆不良地质构造的发育情况.通过对瞬变电磁法的探测能力进行理论上的讨论,对不同地电断面情况下的异常体电磁响应的定性分析,得出用瞬变电磁法探测不良地质体的可行性结论.经过资料处理,查出不良地质构造赋存的位置,解释结果与钻探资料完全吻合. 相似文献
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抗旱保水剂膨润土-聚丙烯酸盐吸水树脂研究 总被引:2,自引:0,他引:2
利用丙烯酸盐在蒙脱石层间进行原位聚合,研究开发一种适用于农林业的抗旱保水剂。实验结果表明:聚合产物的综合性能较为理想,吸水树脂的保水作用主要体现在能够吸收大量的水,并且在压力下不脱水。 相似文献
55.
为了明确折扣方式下应税金额的确定方法,分别从计税销售额、营业额和所得额等方面进行分析,其结果将使纳税人的财务会计处理和具体纳税操作更为规范和准确。 相似文献
56.
Zheng Jianyuan 《中国海洋湖沼学报》1986,4(3):304-312
The present paper is an introduction of a universal model of cluster and discrimination in the field of fisheries science.
The mathematical principle and algorithm are described and the application results analysed.
This model is called “weighted generalized distance” method, based on the principle of “minimum distance”. For different types
of data, different methods are put forward. The quantitative attributes are standarized by “norm” method and the qualitative
attributes are quantified by indicative value based on Shannon's information theory to locate the specimen in the coordinates.
An approach by progressive readjustment of pivotal points is employed for the cluster rational. Finally, any new specimen
can be discriminated by the principle of “minimum distance”, too. 相似文献
57.
Univariate and multivariate stress release models are fitted to historical earthquake data from North China. It is shown that a better fit is obtained by treating separately the Eastern part of the region, including the North China Plain and Bohai Sea, and the Western part of the region, including the Ordos Plateau and its Eastern boundary. Further improvement is obtained by fitting the large events (M7.6) and smaller events in the Western region by different stress release models. The comparisons are made by computing the likelihoods of the fitted models and discounting the number of parameters used by Akaike's AIC criterion. The models are used to develop long-term risk scenarios for the East and West regions. 相似文献
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