排序方式: 共有33条查询结果,搜索用时 15 毫秒
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张宏远 《矿物岩石地球化学通报》2012,31(1):52-56
矿物改造机制是容易被岩矿研究人员忽视的“成因矿物学”新领域之一,主要涉及矿物诞生之后的变化过程.变形矿物及岩石显微构造定性研究已经发展成熟,但造岩矿物显微构造变形与流体运动学和动力学关系的定量研究仍是地学前缘问题.从解析构造学原理出发,将国内外定量研究问题概括出三方面:(1)变形-变质期次与同变形变质温压计;(2)利用同位素年代学分析某期次变形年龄;(3)某期次矿物蠕变机制、差异应力估算及岩石流动定律.并从理论和应用两方面评述了一些实例,认为建立“成因矿物学”实验室,对于系统研究矿物学问题具有重要意义. 相似文献
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Least-squares collocation, geophysical inverse theory and geostatistics: a bird's eye view 总被引:1,自引:0,他引:1
Ute Christina Herzfeld 《Geophysical Journal International》1992,111(2):237-249
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Edmund Penning-Rowsell Peter Floyd David Ramsbottom Suresh Surendran 《Natural Hazards》2005,36(1-2):43-64
This paper presents an outline methodology and an operational framework for assessing and mapping the risk of death or serious harm to people from flooding, covering death and physical injuries as a direct and immediate consequence of deep and/or fast flowing floodwaters (usually by drowning), and deaths and physical injuries associated with the flood event (but occurring in the immediate aftermath). The main factors that affect death or injury to people during floods include flow velocity, flow depth, and the degree to which people are exposed to the flood. The exposure potential is related to such factors as the “suddenness” of flooding (and amount of flood warning), the extent of the floodplain, people’s location on the floodplain, and the character of their accommodation. In addition, risks to people are affected by social factors including their vulnerability and behaviour. A methodology is described for estimating the likely annual number of deaths/injuries. This is based on defining zones of different flood hazard and, for each zone, estimating the total number of people located there, the proportion that are likely to be exposed to a flood, and the proportion of those exposed who are likely to be injured or killed during a flood event. The results for each zone are combined to give an overall risk for each flood cell and/or community. The objective of the research reported here is to develop a method which could be applied using a map-based approach in which flood risks to people are calculated and displayed spatially for selected areas or communities. The information needed for each part of the process is described in the paper, and the further research to provide the required information is identified. 相似文献
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P点铅及其应用意义 总被引:3,自引:0,他引:3
在铅同位素研究中,异常铅是经常遇到并难于解释的问题。在一个矿区或矿带范围内,某些矿床的铅同位素资料中往往显示存在两种类型的铅:具有单阶段演化历史的正常铅和具有两个(或多个)阶段演化历史的异常铅。在常规的铅同位素组成图解上,这两种铅的数据点有时构成异常铅等时线,正常铅则位于等时线上含放射性成因铅最低的位置处。如果这种正常铅能给出合理的矿化年龄,并且该年龄与容矿围岩的成岩年龄基本一致,但显著老于异常铅瞬间增长模式年龄,那么,这种正常铅可能是异常铅等时线的起点,笔者称其为P点铅。显然,异常铅是后期放射性成因铅加入到P点铅形成的,P点铅的模式年龄为异常铅来源区的年龄:利用P点铅及异常铅等时线的资料,可以计算获得异常铅的矿化年龄。因此,P点铅这个概念的提出,为探讨矿化年龄问题开辟了一条新途径。文章还以加拿大和北欧地区某些矿床的铅同位素资料为例,讨论了在实际成矿过程中是否有P点铅存在的问题,讨论了P点铅在矿床成因研究中的重要意义。并给出了如何判断P点铅的具体条件。 相似文献
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北祁连-河西地区强震地点预测 总被引:10,自引:5,他引:5
借助弹性块体边界负位错模型,获取了北祁连 河西地区1971~2000年5个时段地壳垂直运动反映的 构造块体及其边界断层运动、变形参量及构造梯度场的时空演化图像,高应变能积累部位和锁定能量强度。研究 了与门源Ms6.4、景泰Ms6.2、永登Ms5.8、景泰Ms5.9、玉门Ms5.9以及2003年10月25日民乐 山丹Ms6.1等 强震孕育有关的背景性前兆特征,初步建立了该区强震地点判定的定量依据:①在较大范围强烈隆起区内及其边 缘、梯度场高值区内及其边缘,尤其是与构造走向较为一致、隆起量5mm/a以上或梯度值8×10-8/a以上能达到 方圆50~100km甚至更大的区域;②强位错(3mm/a以上)锁定区段及其附近,较强负位错应力降或负位错地震 矩(分别为5×103Pa/a和5×1016Nm/a左右甚至更高)区段及其附近;或者显著加强段及其附近,可能发生6级左 右或6级以上地震。对应的异常越突出、项数越多、位置越重合,发震危险性越大。 相似文献
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主要通过大量房屋分摊面积、分摊系数的计算实例,由传统的房屋分摊面积、分摊系数计算方法,推导出简便实用的、准确的分摊面积、分摊系数计算公式;通过实用简便的分摊面积、分摊系数计算公式,可直接准确地计算出房屋各套内的分摊面积,分摊面积计算工作由繁锁变为简便准确,节省大量工作时间。 相似文献