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排序方式: 共有369条查询结果,搜索用时 46 毫秒
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对冲绳海槽1984-1990年的实测热流值,利用数字滤波方法计算,得到反映该区深部地壳热状态的区域热流值为80-160mW/m^2,用B样条函数法对其作数值模拟,计算出海槽地温场模式,并以此研究冲绳海槽海底高热流的形成机制,得出冲绳海槽热流值的区域性变化与綦中地质构造格局呈正相关,高热流是该区现代构造活动所致,其明显特征是地壳减薄,地幔上拱等结论。 相似文献
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抽水引起的含水层水平应变──地裂缝活动新机理 总被引:13,自引:0,他引:13
基于Darcy -Gersevanov广义渗流关系式 ,本文首先导出了单井定流量抽水引起的泰斯承压含水层水平运动和应变解析表达式 ,并据此提出了抽水诱发地裂缝活动的含水层水平应变新机理 ,其主要观点为 :受井栅的约束阻挡作用 ,抽水活动将在含水层内部形成近井径向挤压区和远井径向拉张区两个应变区域 ,随着抽水时间的增长 ,近井径向挤压区将逐渐向外扩展 ;当地裂缝及其下伏断层或裂隙位于抽水活动引起的径向拉张应变区域时 ,地裂缝将出现加速活动 ;反之 ,当地裂缝处于抽水活动引起的径向挤压应变区域时 ,地裂缝活动反而受到抑制。上述地裂缝活动机理通过大同机车工厂现场抽水实验得到了初步证实。 相似文献
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Susan Subak 《Climate Policy》2003,3(2):107-122
Concern over the “non-permanence” or reversibility of carbon sequestration projects has been prominent in discussions over how to develop guidelines for forest project investments under the Clean Development Mechanism (CDM) of the UNFCCC Kyoto Protocol. Accordingly, a number of approaches have been proposed that aim to help ensure that parties do not receive credit for carbon that is lost before project obligations are fulfilled. These approaches include forest carbon insurance, land reserves, and issuance of expiring credits. The potential costs of each of these different approaches are evaluated using a range of assumptions about project length, risk and discount rate, and a comparison of costs is ventured based on the estimated reduction in value of these credits compared with uninsured, and permanent credits. Obstacles to participation in the different approaches are discussed related to problems of long-term commitments, project scale, rising replacement costs, and low credit value. It is concluded that a system of expiring credits, which could be coupled with insurance or reserves, could guarantee obligations that span time-scales longer than that of conventional insurance policies while maintaining incentives for long-term sequestration. 相似文献
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宝鸡某场地污染土的分析评价 总被引:5,自引:0,他引:5
宝鸡某场地由于长期堆放食盐,造成地基上污染、通过勘察,查明了污染土层,进行了腐蚀性测试和评价,对场地污染区与非污染区土的物理力学性质指标进行了对比,并分析了土的污染机理,提出了防护措施。 相似文献
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Study of Sorptional Properties of the Cation Exchanger KB-2M with Macroreticular Structure for Recovery of Zinc Ions from Sewage and Rinsing Water Although a number of ion-exchange methods have been employed for the recovery of some transition metals from industrial effluents, knowledge about ion-exchange resins with macroreticular structure is poor. The present paper describes the mechanism of sorption on such exchangers and their application for recovery of zinc from sewage rinsing water. Ion exchanger of macroreticular structure are polymers with long-chained cross-linking agents. We have synthesized carboxylic ion-exchange resins by hydrolysis of copolymerisates of methyl acrylate with different cross-linking agents: divinylbenzene, divinyl sulfide, divinyl ester of ethylene glycol and divinyl ester of di- or triethylene glycol. The sorption process on modifications of the carboxylic resins KB-2 of various structure was studied with different methods: potentiometric titration, infrared spectroscopy, electron microscopy, X-ray structural analysis. The initial zinc concentration in rinsing water was 0.05 mol/L at pH from 3 to 6. For the sorption, 0.2…1.0 g of resin were equilibrated with 100 mL of zinc solution. After equilibrium (12 h), the resin was separated from solution. The zinc ions were determined by atomic absorption spectrometry after stripping with 100 mL of 10% sulfuric acid. The distribution ratio D was calculated (D: mmole of Zn sorbed per gram of resin divided by mmole of Zn per millilitre of solution). By means of infrared spectroscopy, the mechanism of sorption of zinc ions from rinsing water was determined. There may be a possibility of the formation of complexes in the cation-exchange resin phase. It was found out in this paper that the cation-exchanger KB-2M of macroreticular structure is the most effective for the sorption of the Zn2+-ions from sewage and rinsing water. 相似文献
10.
Jan
ílený 《Tectonophysics》2004,383(3-4):133-147
The retrieval of earthquake moment tensor (MT) requires the response of the medium, in which seismic waves travel from the hypocenter to the stations, to be known. In inverting long-period (LP) seismic data (teleseismic and LP regional records), a gross earth model is sufficient; with decreasing periods, a more detailed model is needed. This is the case when waveforms of weak earthquakes at regional distances are to be inverted. Regional moment tensors (RMTs) of mostly Mediterranean earthquakes are determined on a routine basis by the Swiss Seismological Survey (SED) by using averaged models of the earth's crust. By inverting broad-band records of the Mw=4.8 earthquake near Udine, N Italy, on Feb. 14, 2002, we tested the sensitivity of the MT solution with respect to possible errors in the earth model used and in the location of the hypocenter depth. We perturbed the P and S velocities and the thickness in the 1-D earth model in the range from 3% to 30% of the parameter values and constructed estimates of confidence regions of the MT and error bars of the source time function (STF) and scalar moment in three frequency bands. Similarly, these error characteristics were determined assuming a mislocation in the hypocenter depth. We found that, in the band of periods from 25 to 50 s, the mechanism is resolved well (at the confidence level 95% at least) up to an earth model uncertainty of 30%, in the passband 10–25 s up to about 10%, but it is undetermined completely at periods of 5–10 s. An error in hypocenter depth of as much as double the value reported by the location procedure does not destroy the resolution of the mechanism at periods above 10 s. In the RMT catalog of the SED, earthquakes of Mw greater than about 3.5 are processed at periods above 30 s; thus, the solutions for these events are robust with respect to a possible uncertainty in the earth model used. Mechanisms of weaker earthquakes, retrieved from short periods, should be interpreted with caution. 相似文献