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101.
Ran Ye Haibo Zhang Yige Yu Qing Xu Dandi Shen Min Ren Lian Liu Yanhong Cai 《海洋学报(英文版)》2023,42(4):103-113
Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically... 相似文献
102.
本文叙述了用活性炭色层柱分离、亚硫酸钠解吸、TMK-异戊醇萃取比色测定痕量金的方法。采用了以硫酸钴、铬酸钾和硫酸铜等无机盐配制模拟标准系列,可以长期使用。本法操作简单,快速,成本低,工效高。一人一天可以分析30个以上试样,能测定出1×10~(-3)ppm的金含量,适用于地质普查金矿中大批试样的分析。 相似文献
103.
The Hannuoba basalts are a suite of associated rocks consisting of alkali basalts and tholeiites. The alkali basalts can be divided into the K-rich type and the Na-rich type, while the tholeiites are almost solely of the Na-rich type. These two types of basalt are characterized as being obviously rich in light rare earth elements, as is shown in the chondrite-normalized REE patterns exhibiting positive Eu anomalies. However, significant differences in (La / Yb)N and Eu / Eu* ratios are noticed between these two types of basalt. They seem to have been derived from varying-degree partial melting of mantle rocks. 相似文献
104.
本文运用地洼成矿理论和构造地球化学的方法,研究了区内 F_1成矿断裂等的构造特征和元素的变化规律以及铀等成矿元素的不断累增富集的成矿作用过程.区内钠矿床的形成大体上经历了铀的预富成岩(形成铀源地质体)→断裂动力改造热液(热水)成矿→表生淋积等三个主要发展阶段,形成了一个具有层控特征的多因复成铀矿床,从而为本区指明了找矿方向. 相似文献
105.
Jun Liu Letitia Topor Jianzhong Zhang Alexandra Navrotsky Robert C. Liebermann 《Physics and Chemistry of Minerals》1996,23(1):11-16
High temperature drop-solution calorimetry in molten 2 PbO · B2O3 at 1044 K for coesite and stishovite polymorphs of silica was carried out to determine the enthalpy of the coesite-stishovite transition. These experiments were performed on high-purity, single-phase samples of coesite and stishovite. Our new value for the enthalpy of the coesitestishovite transition (ΔH 298 0 ) is 29.85 ± 0.78 kJ/mol, which is about 35% lower than previously reported by Akaogi and Navrotsky (1984) and Holm et al. (1967), but which compares well with new measurements by Akaogi et al. (1994b). Using these new data, we have calculated the equilibrium phase boundary between coesite and stishovite and obtained a slope, dP/dT=0.0031 (2) GPa/K. This calculated slope is in good agreement with that determined [0.0026 (2) GPa/K] from the in-situ X-ray diffraction study of Zhang et al. (1996). 相似文献
106.
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108.
Da-Chao Lin Jing-Luo Cai Zhang-Lin Guo Fan-Lei Zeng Feng-Ping An Hai-Bo Liu 《Natural Hazards》2013,65(1):581-603
109.
Yu-long Luo Liang Qiao Xing-xing Liu Mei-li Zhan Jin-chang Sheng 《Natural Hazards》2013,65(3):1361-1377
The long-term large hydraulic head in flood season is the main cause of suffusion failure or dam break, while the suffusion failure mechanism in this case has not been specially studied. First, a newly designed hydro-mechanical coupling suffusion apparatus was introduced. Second, two short-term suffusion experiments under different confining pressures were carried out to determine the suitable large hydraulic heads. Finally, four experiments on suffusion under long-term large hydraulic heads and different confining pressures were performed to investigate the influences of the long-term large hydraulic heads and the confining pressures on the evolution of suffusion. The results indicate that: (1) The signs of suffusion failure in the short-term experiments are the sudden decrease in hydraulic gradient and the sharp increase in eroded mass. While the flow rate in the long-term experiments appearing suffusion failures increases rapidly with the decrease in hydraulic gradient. (2) The suffusion failure in the long-term large hydraulic head experiment is more likely to happen and much more serious than that in the short-term experiment. The long-term large hydraulic head can reduce the suffusion failure hydraulic gradient significantly and increase the eroded mass dramatically. The results gained here provide a deeper understanding on the suffusion failure caused by the rapid increase in the high water level upstream the hydraulic earth structures in flood season. 相似文献
110.
The Beijing storm of 21 July attracted public and social attention widely. Recently, some scientists expressed their opinion that urbanization has exacerbated the storm. However, our analysis suggests that while urbanization might have played some role, it is mainly the topographic effect that made the storm intense. Our conclusion is that the Beijing storm of 21 July is generated due to natural climatic factors in a changing climate system. Moreover, we think that the factor that contributes to the tremendous flooding disaster of 21 July is the low standards for mountain torrents control for medium and small rivers in the affected region. Therefore, the mountain torrents disasters control and medium and small rivers harnessing should be the foremost task in China’s water conservancy construction in the future, and effective adaptation strategies should also be developed and implemented to cope with the climate change impacts. 相似文献
