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311.
江苏平原地区(淮河流域)潜水碘含量控制因素探讨 总被引:1,自引:0,他引:1
本文通过工作区潜水碘含量的分布特点,与所处土壤、水文地质条件、地形地貌等一起进行综合分析,对地下水中碘的控制因素有了一个全新的认识:与前人认为地下水中碘的含量与有机质成正比的观点不同的是,本文认为地下水中碘的含量与有机质含量无固定关系,但有机质有助于促进水溶性碘的增加,相似水文地质条件下成正比;地下水径流条件对潜水碘含量影响重大,径流条件较好的丘陵、岗地往往较低,地势低平、径流条件较差的洼地和泛滥沉积区往往为高碘地区;相同水文地质条件下,地下水中的碘含量与土壤中的含量成正比;碘的另一重要特征是在地下水中的浓度较为稳定,随时间、开采而变化不大。 相似文献
312.
济阳坳陷中生界分布广泛,具有油气成藏的基本地质条件,并取得了一定的勘探发现,但其勘探程度和研究程度相对较低,包括地层划分、沉积体系、储层特征、控藏因素等。特别是地层时代、分层与分界等基本的地质问题尚存在不同的观点和认识。根据区内14口井的10个火山岩全岩样品和79个小于2μm的泥岩自生伊利石样品,开展K-Ar法同位素年代地层学测定,分别确定了中生界的坊子组、蒙阴组、三台组和西洼组的绝对年龄值,将坊子组划归下侏罗统,蒙阴组为中侏罗统,缺失上侏罗统,并明确了各组的接触关系。 相似文献
313.
Hua Li Benqiang Rao Gaohong Wang Si Shen Dunhai Li Chunxiang Hu Yongding Liu 《Environmental Earth Sciences》2014,71(1):245-253
Artificial biological soil crusts (ABSCs), formed by inoculating Microcoleus vaginatus Gom. and Scytonema javanicum Born. et Flah. onto the topsoil of desert dunes, proved to be effective tools for the stabilization of moving dunes and promotion of soil fertility. As dominant driving forces in arid habitats, the abiotic environmental conditions of undulating dunes produce a gradient of abiotic stresses on cyanobacteria. Cyanobacteria are considered pioneering phototrophs in early soil crust communities in deserts. In this study, the development of ABSCs under various environmental site conditions was investigated using 16S rRNA-based polymerase chain reaction, denaturing gradient gel electrophoresis (DGGE), and soil property measurements. After inoculation in 2002 and long-term development, patchy moss crusts were observed on the dunes. All of the available sequenced bands in the DGGE gels belonged to Oscillatoriales and Nostocales. The dominant Nostocales genus in the ABSCs was still Scytonema; however, more Oscillatoriales genera were identified, which belonged to Microcoleus and Phormidium. The cyanobacterial compositions of different slope types were significantly distinct (p < 0.05), particularly those from windward slopes. The crusts of the top-dune slopes were more heterogeneous. In addition, the soil physicochemical properties and richness indices of the windward slopes were significantly lower than those of the leeward and interdune slopes (p < 0.05). Compared with uninoculated control dunes, all of the inoculated dunes had far higher biodiversities. 相似文献
314.
正The Mengyejing potash salt deposit(MPSD)is the only pre-Quaternary potash salt deposit in China.The MPSD is located in the southern Simao Basin,southeastern Tibetan Plateau.The MPSD,along with rock salts and clastic rocks, 相似文献
315.
316.
Jun-Hui Fan Denis Bastieri Jiang-He Yang Yi Liu Tong-Xu Hua Yu-Hai Yuan De-Xiang Wu 《中国天文和天体物理学报》2014,(9)
We selected 457 blazars(193 flat spectrum radio quasars, 61 lowsynchrotron peaked blazars, 69 intermediate-synchrotron peaked blazars and 134high-synchrotron peaked blazars) from the second Fermi-LAT catalog(2FGL) of γ-ray sources, which have X-ray observations. We calculated the lower limits for their Doppler factors, δγ, and compared the lower limits with the available Doppler factors and the apparent superluminal velocities in the literature. 相似文献
317.
The hydrodynamic response of a porous flexible circular-cylinder in regular waves was analytically studied. To simplify the problem, the cover and the bottom of the cylinder were ignored. Small amplitude water wave theory and structural responses were assumed. The velocity potentials were solved using the Fourier-Bessel series expansion method and the least squares approximation method. The convergence of the series was numerically tested to determine the number of terms in the series expansion. Two types of installations were considered for deformation, hydrodynamic forces, structural flexibility, drafts, and porosity. The present study represented a preliminary step in the study of the fish cage. 相似文献
318.
1 INTRODUCTION In southern high latitudes, recent observations have shown a standing mode of ACW (Antarctic Circumpolar Wave) with eastward propagation across the Southern Ocean of the Antarctic in co- varying SST (sea surface temperature) and SLP (sea le… 相似文献
319.