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571.
As an important innovation flow, venture capital has been examined in urban network research. However, the segmentation of capital categories and the cross-scale connection of capital remain scarcely analyzed. This study focuses on the structure and industry differentiation of venture capital flows in the Guangdong-Hong Kong-Macao Greater Bay Area(GBA) and its cross-scale network characteristics. Based on a venture capital database covering capital amount, investment subject address information,... 相似文献
572.
Gold and palladium have been determined in 42 geological reference samples with graphite furnace AAS after aqua regia digestion and SnCl2 -Hg extraction. A brief discussion on the quality of these analyses also is presented. 相似文献
573.
In Europe the Chalk constitutes a major source of potable water supply. Its outcrop forms extensive tracts of agricultural
land, where the groundwater resources largely originate as infiltrating excess rainfall. Research on the unsaturated zone
of the aquifer beneath such cultivated land should allow an assessment of nutrient leaching losses from the associated highly
permeable soils and the prediction of future groundwater quality trends. Pore-water profiles for nitrate and numerous other
constituents from a site of exceptionally detailed study are presented and compared to results from sites elsewhere in eastern
England to demonstrate the impact of modern arable agriculture. Environmental isotopes have also been investigated in depth
to aid the study. The problems in evaluating the evolution of the unsaturated zone profiles are discussed.
Presented at the International Symposium, International Association of Hydrogeologists, “Impact of Agricultural Activities
on Ground Water Quality and Quantity,” Prague, Czechoslovakia, September, 1982. 相似文献
574.
H.V. Warren S.J. Horsky A. Kruckeberg G.H.N. Towers J.E. Armstrong 《Journal of Geochemical Exploration》1983,18(3):169-173
Summary of biogeochemical prospecting for mercury mineralization in the Pinchi Fault is given. One thousand two hundred and eight plant samples were collected and analyzed for mercury. In mineralized areas the typical mercury content of dried plants was not less than 0.2 and 0.4 μg/g and even concentrations between 0.6 and 1.6 μg/g were observed. In nonmineralized zones at least 90% of the plants contained no more than 0.15 μg/g of mercury. Analytical and sampling procedures are described. 相似文献
575.
A geochemically and mineralogically diverse group of granitoids is present within an area of 900 km2 in the southern Snake Range of eastern Nevada. The granitoids exposed range in age from Jurassic through Cretaceous to Oligocene and include two calcic intrusions, two different types of two-mica granites, and aplites. The younger intrusions appear to have been emplaced at progressively more shallow depths. All of these granitoid types are represented elsewhere in the eastern Great Basin, but the southern Snake Range is distinguished by the grouping of all these types within a relatively small area. The Jurassic calcic pluton of the Snake Creek-Williams Canyon area displays large and systematic chemical and mineralogical zonation over a horizontal distance of five km. Although major element variations in the pluton compare closely with Daly's average andesite-dacite-rhyolite over an SiO2 range of 63 to 76 percent, trace element (Rb, Sr, Ba) variations show that the zonation is the result of in situ fractional crystallization, with the formation of relatively mafic cumulates on at least one wall of the magma chamber. Models of trace element and isotopic data indicate that relatively little assimilation took place at the level of crystallization. Nonetheless, an initial 87Sr/86Sr value of 0.7071 and δ 18O values of 10.2 to 12.2 permil suggest a lower crustal magma that was contaminated by upper crustal clastic sedimentary rocks before crystallization. The involvement of mantle-derived magmas in its genesis is difficult to rule out. Two other Jurassic plutons show isotopic and chemical similarities to the Snake Creek-Williams Canyon pluton. Cretaceous granites from eastern Nevada that contain phenocrystic muscovite are strongly peraluminous, and have high initial Sr-isotope ratios and other features characteristic of S-type granitoids. They were probably derived from Proterozoic metasediments and granite gneisses that comprise the middle crust of this region. Another group of granitoids (including the Tertiary aplites) show chemical, mineralogic, and isotopic characteristics intermediate between the first two groups and may have been derived by contamination of magmas from the lower crust by the midcrustal metasediments. 相似文献
576.
577.
Cui Yun-liang Qi Chang-guang Zheng Jin-hui Wang Xin-quan Zhang Shi-min 《Geotechnical and Geological Engineering》2021,39(7):4833-4842
Geotechnical and Geological Engineering - The field static load test method was adopted for two test piles in a project in Zhejiang area of China, analyze the effect of post-grouting technique on... 相似文献
578.
Xiao Yang Zhao Chang Sun Yue Wang Shun Wu Huanran Chen Hui Liu Hanlong 《Acta Geotechnica》2021,16(5):1391-1400
Acta Geotechnica - One-dimensional compression tests on quartz sands treated by microbially induced carbonate precipitation (MICP) were carried out to evaluate the effects of gradation and calcium... 相似文献
579.
580.
Wet granular materials are three-dimensionally simulated by the discrete element method with water bridges incorporated between particles. The water bridges are simplified as toroidal shapes, and the matric suction is constantly maintained in the material. A comparison with experimental tests in the literature indicates that the toroidal shape approximation may be one of the best choices with high practicability and decent accuracy. Mechanical behaviours of wet granular materials are studied by triaxial tests. Effects of particle size distributions and void ratios are investigated systematically in this study. The hydraulic limit of the pendular state is also discussed. It gives the capillary cohesion function which is not only determined by the degree of saturation but also positively correlated to relative density and particle size polydispersity and inversely proportional to mean particle size. Furthermore, the capillary strengthening effect is also analysed microscopically in aid of the Stress–Force–Fabric relationship, mainly in fabric anisotropy, coordination number and stress transmission pattern, which revealed the micro-mechanisms of the additional effective stress induced by capillary effect. 相似文献