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691.
1IN TR O D U C TIO NA s a persistentand toxic pollutant, cadm ium (C d) canresultin m any adverse health effects in a variety oftis-suesand organssuch asthe lung,kidney,urinary,blad-der,pancreas,breast and prostate (SA TA R U G etal.,2003).C adm ium in so…  相似文献   
692.
海洋石油污染及其生物修复   总被引:1,自引:0,他引:1  
文章根据海洋油污染的现状,介绍了海洋石油污染的来源、危害、转归以及对污染的生物修复等内容。指出了限制微生物降解的因素以及如何提高降解效率的措施。生物修复对环境和人类影响小,修复速度快且费用较低,在海洋油污染治理中该方法具有广阔应用前景。  相似文献   
693.
The aims of this paper are to analyze the effects of microparameters on macroparameters of flat-jointed bonded-particle materials of particle flow code in two dimensions (PFC2D) and improve the efficiency of trial-and-error method in calibration of microparameters. The trial-and-error method is always used to calibrate the microparameters for a PFC2D model, but it is time-consuming and empirical. To improve the efficiency of the trial-and-error method, the effects of microparameters on macroparameters need to be analyzed. By using the trial-and-error method, a desirable set of microparameters for a uniaxial compression PFC2D model (with a flat-joint contact model as the contact model) of limestone were calibrated to match the macroscopic properties obtained from laboratory tests. Based on the calibration set of microparameters, effects of microparameters on macroparameters of the PFC2D model were studied by the orthogonal design method. On this basis, a flowchart of calibrating microparameters via trial-and-error method was proposed. This flowchart was used to calibrate the microparameters of granite. The macroparameters and failure characteristics determined from numerical simulation were very similar to those of laboratory tests, confirming the effectiveness of the proposed flowchart.  相似文献   
694.
地壳中流体的大规模流动系统及其成矿意义   总被引:12,自引:0,他引:12  
地壳中的水量相当于海洋体积的水量,已确定的水溶液活动深度可达20km,根据驱动力的不同,地壳中主要存在三大流动系统,即重力,浮力和应力驱动系统。本文评述了当前国际上有关大规模流体运移研究扩要进展和发展趋势,介绍了有关流动系统的模式和运动机制,并简要论述了其成矿意义。文章指出,目前区域古流体场地球化学背景问题已成为区域规律和热液成矿理论中一个不容回避的关键课题,地壳中大规模流动系统将成为今后地质流体研究的重要方向之一。  相似文献   
695.
For the rising branch of Cycle 22, 1987 January—1989 November, we plot the daily total flux S at each of the five wavelengths 2.0, 3.4, 6.0, 10.7 and 21.2 cm against the apparent sunspot area of the dominant sunspot Ay and find that, for several large active areas, the locus is located below the average regression line, and the increase in the radio flux is insignificant compared to the increase in the sunspot area.  相似文献   
696.
Interannual variability(IAV) in the barrier layer thickness(BLT) and forcing mechanisms in the eastern equatorial Indian Ocean(EEIO) and Bay of Bengal(BoB) are examined using monthly Argo data sets during 2002–2017. The BLT during November–January(NDJ) in the EEIO shows strong IAV, which is associated with the Indian Ocean dipole mode(IOD), with the IOD leading the BLT by two months. During the negative IOD phase, the westerly wind anomalies driving the downwelling Kelvin waves increase the isothermal layer depth(ILD). Moreover, the variability in the mixed layer depth(MLD) is complex. Affected by the Wyrtki jet, the MLD presents negative anomalies west of 85°E and strong positive anomalies between 85°E and 93°E. Therefore, the BLT shows positive anomalies except between 86°E and 92°E in the EEIO. Additionally, the IAV in the BLT during December–February(DJF) in the BoB is also investigated. In the eastern and northeastern BoB, the IAV in the BLT is remotely forced by equatorial zonal wind stress anomalies associated with the El Ni?o-Southern Oscillation(ENSO). In the western BoB, the regional surface wind forcing-related ENSO modulates the BLT variations.  相似文献   
697.
Spatially homogeneous and anisotropic LRS Bianchi type-I string cosmological models are studied in the frame work of general relativity when the source for the energy momentum tensor is a bulk viscous fluid containing one dimensional strings. A barotropic equation of state for the pressure and density is assumed to get determinate solutions of the field equations. The bulk viscous pressure is assumed to be proportional to the energy density. The physical and kinematical properties of the models are discussed. The role of bulk viscosity in getting an inflationary phase in the universe is studied.  相似文献   
698.
The dunes in estuary of Tumen River in China lie to the area between the Jiushaping and Fangchuan in the left bank of Tumen River (Fig.1). The dis-tance is about 15~20 km between the dunes and the coast. It ranges from China to D. P. R. Korea and Russia. The range of the height of dunes is about 15~20 m and the width is 100~200 m. By the re-connaissance, we protracted 9 section planes of the dunes and collected 40 sand samples of the dunes, and identified the sedimentary environment …  相似文献   
699.
Forty-six mining-induced seismic events with moment magnitude between ?1.2 and 2.1 that possibly caused damage were studied. The events occurred between 2008 and 2013 at mining level 850–1350 m in the Kiirunavaara Mine (Sweden). Hypocenter locations were refined using from 6 to 130 sensors at distances of up to 1400 m. The source parameters of the events were re-estimated using spectral analysis with a standard Brune model (slope ?2). The radiated energy for the studied events varied from 4.7 × 10?1 to 3.8 × 107 J, the source radii from 4 to 110 m, the apparent stress from 6.2 × 102 to 1.1 × 106 Pa, energy ratio (E s/E p) from 1.2 to 126, and apparent volume from 1.8 × 103 to 1.1 × 107 m3. 90% of the events were located in the footwall, close to the ore contact. The events were classified as shear/fault slip (FS) or non-shear (NS) based on the E s/E p ratio (>10 or <10). Out of 46 events 15 events were classified as NS located almost in the whole range between 840 and 1360 m, including many events below the production. The rest 31 FS events were concentrated mostly around the production levels and slightly below them. The relationships between some source parameters and seismic moment/moment magnitude showed dependence on the type of the source mechanism. The energy and the apparent stress were found to be three times larger for FS events than for NS events.  相似文献   
700.
上扬子地区四川盆地南部威远—泸州地区上奥陶统凯迪阶五峰组和志留系底部兰多维列统龙马溪组黑色笔石页岩沉积于滞留缺氧海底且富含有机质,是页岩气的主产层位,介于五峰组和龙马溪组之间的奥陶系顶部赫南特阶观音桥组通常是含腕足类以及三叶虫的灰岩沉积,其化石组成是冈瓦纳冰川事件最盛期在低纬度陆表海区的产物,岩石学微相特征研究能进一步诠释当时海底沉积环境。本文根据威远地区的W2、W4H10井,泸州地区的L2井、L4井、L5井、L6井、L7井、L8井、L9井观音桥组微相鉴定识别生物多样性,除常见的Hirnantia腕足动物群、三叶虫Dalmanitina等壳相化石外,还出现海百合、腹足类Homotoma、双壳类、海绵动物碎片和虫管遗迹化石Chondrites(丛藻迹),其化石组成记录了该层位的生物多样性。观音桥组沉积时该区海底富氧环境有利于底栖动物生存,远岸区海底水动力弱,化石粒度偏细且部分化石破碎程度高,未见大量复体珊瑚和钙藻等典型暖水区化石,反映出远岸相观音桥组海底水温可能偏低。  相似文献   
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