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141.
Thorsten Christian Rudolf J. Schneider Harald A. Frber Dirk Skutlarek Michael T. Meyer Heiner E. Goldbach 《洁净——土壤、空气、水》2003,31(1):36-44
In the last years more and more often detections of antimicrobially active compounds (“antibiotics”) in surface waters have been reported. As a possible input pathway in most cases municipal sewage has been discussed. But as an input from the realm of agriculture is conceivable as well, in this study it should be investigated if an input can occur via the pathway application of liquid manure on fields with the subsequent mechanisms surface run‐off/interflow, leaching, and drift. For this purpose a series of surface waters, soils, and liquid manures from North Rhine‐Westphalia (Northwestern Germany) were sampled and analyzed for up to 29 compounds by HPLC‐MS/MS. In each of the surface waters antibiotics could be detected. The highest concentrations were found in samples from spring (300 ng/L of erythromycin). Some of the substances detected (e.g., tylosin), as well as characteristics in the landscape suggest an input from agriculture in some particular cases. In the investigation of different liquid manure samples by a fast immunoassay method sulfadimidine could be detected in the range of 1…2 mg/kg. Soil that had been fertilized with this liquid manure showed a content of sulfadimidine extractable by accelerated solvent extraction (ASE) of 15 μg/kg dry weight even 7 months after the application. This indicates the high stability of some antibiotics in manure and soil. 相似文献
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143.
运用岩石破裂过程分析RFPA2D系统,研究了岩石介质细观非均匀性对宏观力学行为的影响和微震序列特征. 通过对不同均质度系数m=1.1,1.5,2,3,5的5个样本进行破裂过程的模拟,发现均质度不同会产生不同地震序列类型,主要有:前震-主震-余震型、主震型和震群型. 此外,对5种不同均质度系数的岩石样本破裂过程的模拟表明,岩石介质的非均匀性不仅对岩样宏观强度和宏观变形非线性行为有显著的影响,而且也显著地影响试样破裂模式. 随着均质度系数的提高,主破裂呈现脆断模式. 同时介质的细观结构随机性,也对试样宏观破裂模式产生重要影响. 相似文献
144.
Quartz microstructures developed during non-steady state plastic flow at rapidly decaying stress and strain rate 总被引:7,自引:0,他引:7
Synseismic loading to very high stresses (>0.5 GPa) and subsequent creep during stress relaxation in the uppermost plastosphere at temperatures of ca. 300–350 °C, near the lower tip of an inferred once seismically active crustal scale fault, was proposed based on peculiar microstructures identified in rocks exposed over >100 km2 in the Sesia Zone, European Western Alps. Here we discuss the conspicuous and highly heterogeneous microstructural record of quartz in disseminated small-scale shear zones. Sub-basal deformation lamellae and arrays of elongate subgrains on the TEM-scale indicate an early stage of glide-controlled deformation at high stresses. Distributed brittle failure is indicated by healed microcracks. Very fine-grained recrystallised aggregates with a pronounced crystallographic preferred orientation reflect intense plastic flow by dislocation creep. Locally, a fine-grained foam microstructure indicates a final stage of static grain growth at low differential stress. For the previously inferred peak stresses of about 0.5 GPa and given temperatures, initial strain rates on the order of 10−10 s−1 are predicted by available flow laws for dislocation creep of quartz. We emphasise the importance of short-term non-steady state deformation in the uppermost plastosphere underlying seismically active upper crust. The related heterogeneous record of quartz is governed by the local stress history at constant temperature. 相似文献
145.
Dynamic causes for the opening of the Baikal Rift Zone: a numerical modelling approach 总被引:1,自引:0,他引:1
Previous dynamic models of the Baikal Rift Zone (BRZ) are mostly two-dimensional on vertical plane. In this study, a numerical model of neotectonics in the region on map view was constructed using the adapted PLATES program. The present work is an attempt to test different mechanisms for opening Baikal Rift by comparing the modelled and observed stress and strain rate fields. The following rifting scenarios were tested: (1) pure northwest–southeast extension, (2) pure northeast–southwest compression, (3) oblique rift opening and (4) combined northwest–southeast extension and northeast–southwest compression. The models are calibrated using geologically and GPS-derived strain rates and stress-tensor determinations from fault-slip data and earthquake focal mechanisms. The most successful model requires a combination of NE–SW compression and orthogonal extension. The model results indicate that the present extensional regime in BRZ can be explained by combining the India plate indentation northward into Eurasia, east–west convergence between the North America and Eurasia plates and southeastward extrusion of the Amur plate in northeastern Asia. Predicted fault-slip rates for the best-fit model are consistent with the observed Holocene fault-slip rates in the Lake Baikal region. The generally accepted rotation of the Amur and Mongolia microplates are used as independent constraints for the choice of the best-fit model. These data correlate well with the predicted direction of rotation in our best model. 相似文献
146.
The influence of vorticity and rheology of matrix material on the development of shape-preferred orientation (SPO) of populations of rigid objects was experimentally studied. Experiments in plane strain monoclinic flow were performed to model the fabric development of two populations of rectangular rigid objects with object aspect ratios (Rob) 2 and 3. The density of the rigid object populations was 14% of the total area. Objects were dispersed in a Newtonian and a non-Newtonian, power law matrix material with a power law exponent n of 1.2. The kinematic vorticity number (Wn) of the plane strain monoclinic flow was 1, 0.8 and 0.6 with finite simple shear strain of 4.6, 3.0 and 0.9, respectively. In experiments with Rob=3, the SPO is strongly influenced by Wn and the material properties of the matrix. Deformation of a power law matrix material and low Wn resulted in a stronger SPO than deformation of a linear viscous matrix and high Wn. Strain localization coupled with particle interaction plays a significant role in the development of a shape-preferred orientation. High strain simple shear zones separate trains of rigid objects that are surrounded by low strain zones with Wn lower than the bulk Wn. In fabrics involving populations of objects with Rob=2, rheology of the matrix materials does not systematically influence the intensity of the SPO. 相似文献
147.
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149.
卢万年 《地球科学与环境学报》1993,(2)
本文应用应变能密度与三向应力圆的等价关系,分析修正了莫尔准则,提出用任意确定静水压力下不同洛德参数的极限莫尔圆包络曲线簇作准则线,即谓之为应变能-莫尔准则线,并引用岩土真三轴试验资料进行验证;最后还得出应变能-莫尔屈服条件,分析了屈服曲面和屈服轨迹的形状等。 相似文献
150.
CO2的地质埋存与资源化利用进展 总被引:18,自引:0,他引:18
把CO2注入油气藏、煤层提高油气采收率的方法(CO2-EOR、CO2-EGR、CO2-ECBM),因其在提高石油、天然气和煤层气采收率的同时,又能使一部分CO2永久地埋存于地下,实现油气增产和CO2减排的双赢效果,而成为当今CO2减排最具潜力的现实选择.CO2-EOR(Enhanced Oil Recovery)方法适用于油田开发晚期,通过把CO2注入到比较稳定的油藏,一般可提高油藏采收率达10%~15%;另外把CO2注入到气田中,实施CO2-EGR(Enhanced Gas Recovery).一方面,接近枯竭的气田在没有地层水入侵之前具有巨大的埋存能力,为CO2提供巨大的埋存空间;另一方面注入CO2后,使地层重新增压保持储层中原始的压力,可以保持储层的完整性和安全性.同时,原有的油气圈闭可作为良好的埋存箱能有效地阻止CO2泄漏,使部分CO2能永久地埋存于地下.此外,也可以把CO2注入到煤层中,实施CO2-ECBM(Enhanced Coalbed Methane Recovery),利用煤层对CO2和煤层气(主要为甲烷)吸附能力的差异,实现CO2排替CH4,提高CH4的采收率. 相似文献