排序方式: 共有148条查询结果,搜索用时 31 毫秒
141.
海南抱板金矿田围岩蚀变带中绿泥石的特征及其意义 总被引:1,自引:3,他引:1
通过对海南抱板金矿田围岩蚀变带中绿泥石成分的分析,讨论了蚀变带中绿泥石的成分变化,并由此确定围岩蚀为形成于290~300℃和氧逸度为10^-26~10^-34的条件下,结合含金石英脉的体包裹体研究,从蚀变到成矿物质沉淀,热液的温度和氧逸度是变化的。 相似文献
142.
膨润土的酸化脱色机理研究 总被引:5,自引:5,他引:5
通过对广西田东钙基膨润土的酸化脱色实验研究,表明活性土的脱色能力是其表面积和酸化作用中浸取出的铝离子量的函数;在钙蒙脱石晶体结构处于彻底破坏前的临界点,膨润土具有最大的脱色能力和比表面积。 相似文献
143.
对Cu-Mo-Sn-S四元系500-640℃的相关系进行研究,并对相关的Cu-Sn-S三元系做了进一步研究与测定。实验表明,500℃时Cu-Sn-S系的稳定的三元化合物有Cu_4SnS_4、Cu_4SnS_6(或Cu_(9.75)Sn_(2.17)S_(13))、Cu_5Sn_2S_7(或Cu_(4.90)Sn_2S_(7.01))、Cu_2SnS_3和Cu_2Sn_3S_7(或Cu_2Sn_(3.26)S_(7.51))。这些三元化合物,除Cu_4SnS_4外,都与硫形成双变关系。 Cu-Mo-Sn-S四元系在500℃时相关系主要表现为MoS_2与Cu_4SnS_6、Cu_5Sn_2S_7、Cu_2SnS_3和Cu_2Sn_3S_7等各相的双变关系,以及金属与Cu_4SnS_4、Cu_5Sn_2S_7、Cu_2SnS_3和Cu_2Sn_3S_7的双变关系。 以不同起始原料,不同温度和方法合成Cu-Mo-Sn-S四元系中唯一的四元化合物——硫钼锡铜矿未获得成功。 相似文献
144.
Weiguang Wang Quanxi Shao Shizhang Peng Zengxin Zhang Wanqiu Xing Guiyang An Bin Yong 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(7):881-895
The present study explores the spatial and temporal changing patterns of the precipitation in the Haihe River basin of North
China during 1957–2007 at annual, seasonal and monthly scales. The Mann–Kendall and Sen’s T tests are employed to detect the trends, and the segmented regression is applied to investigate possible change points. Meanwhile,
Sen’s slope estimator is computed to represent the magnitudes of the temporal trends. The regional precipitation trends are
also discussed based on the regional index series of four sub-basins in the basin. Serial correlation of the precipitation
series is checked prior to the application of the statistical test to ensure the validity of trend detection. Moreover, moisture
flux variations based on the NCEP/NCAR reanalysis dataset are investigated to further reveal the possible causes behind the
changes in precipitation. The results show that: (1) Although the directions of annual precipitation trends at all stations
are downward, only seven stations have significant trends at the 90% confidence level, and these stations are mainly located
in the western and southeastern Haihe River basin. (2) Summer is the only season showing a strong downward trend. For the
monthly series, significant decreasing trends are mainly found during July, August and November, while significant increasing
trends are mostly observed during May and December. In comparison with the annual series, more intensive changes can be found
in the monthly series, which may indicate a shift in the precipitation regime. (3) Most shifts from increasing trends to decreasing
trends occurred in May–June, July, August and December series, while opposed shifts mainly occurred in November. Summer is
the only season displaying strong shift trends and the change points mostly emerged during the late 1970s to early 1980s.
(4) An obvious decrease in moisture flux is observed after 1980 in comparison with the observations before 1980. The results
of similar changing patterns between monthly moisture budget and precipitation confirmed that large-scale atmospheric circulation
may be responsible for the shift in the annual cycle of precipitation in the Haihe River basin. These findings are expected
to contribute to providing more accurate results of regional changing precipitation patterns and understanding the underlying
linkages between climate change and alterations of hydrological cycles in the Haihe River basin. 相似文献
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具蹼状构造的垂直 U形潜穴 Diplocraterion广泛产出于全球寒武纪—古近纪的滨浅海相中 ,被认为是 Seilacher(196 4 ,196 7)的 Skolithos遗迹相的主要分子 ,也见于中—新生代的河湖相中 ,被视为高能环境的重要分子。Diplocraterion在古生代陆相地层中的发现仍是首次。产于贵州独山丹林组陆相地层具有水平层理的黑色泥岩中的 Diplocraterion dushanensis ichnosp.nov.其近于平行的 U形栖管由许多的节管组成 ,节管和蹼状构造可能系造迹生物的居住潜穴阶段性地随沉积物的增厚而向上移动的过程中所形成 ,其造迹生物主要生活于泛滥平原相对平静贫氧的水体环境中。 相似文献
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