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121.
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
122.
123.
本文应用Wilson提出的GF矩阵法对方解石进行了正则振动分析。在Urey-Bra-dley简化力场条件下,作了E类振动的拟合计算,获得的力常数和计算频率分别为:K=5.40,H=0.38,F=1.83(md/A和v_3=1420,v_4=707(cm~(-1))。根据归一化位能分布,从理论上把v_3和v_4分别归属于键伸缩振动和弯曲振动。 相似文献
124.
大容山花岗岩带中石榴子石,堇青石的成因研究 总被引:7,自引:0,他引:7
该花岗岩带中石榴子石富MgO而贫MnO,并且具正成分环带构造,证明是原岩残留晶;堇青石与残留包体中堇青石成分相似,均属镁堇青石,Na_2O<0.33%,表明不是岩浆晶出矿物,而是岩浆源区残留晶。矿物谱学工作表明,堇青石中赋存原生CO_2和H_2O,某组成是矿物形成温度的灵敏指示剂;另一方面,由于挥发分的存在,“湿”堇青石畸变系数△不能反映硅铝有序度,而红外分裂指数能够及“干”堇青石△可能能够反映硅铝有序度。石榴子石-堇青石组合是理想的地质温压逸度计,它给出了大容山岩体及旧州岩体源区的T、P、f_(H_2O)和P_(H_2O)。 相似文献
125.
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
126.
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
127.
云南兰坪啦井温泉喷流沉积矿化体的发现及其地质意义 总被引:6,自引:0,他引:6
啦井温泉喷流沉积物中富集了Mn、Zn、Sr、Ba及其他元素,作者首次发现其已构成多金属矿化体,为此进行了详细的地球化学研究。温泉属硫酸盐型弱酸性水,C、H、O同位素表明,温泉成因于循环大气降水。从沉积特征分析,温泉经历了爆发喷流期与渗流期的演化过程。 相似文献
128.
Zhang Qian Zhang Baogui Cao Yubo Pan Jiayong Zeng Tianyuand Hao ShuzhiInstitute of Geochemistry Academia Sini Guiyang Guangxi 《《地质学报》英文版》1994,68(1)
The Dajiangping pyrite deposit located in the middle sector of the Yunkai uplift in western Guangdong is a stratiform sulphide deposit occurring in Sinian marine clastic and fine clastic rocks. The formation of the deposit was related to submarine exhalation and hot brine deposition. A part of it was reformed by late-stage hydrothermal solution. The δ34S values of pyrite vary from - 25.55‰ to +21.07‰, which are inversely proportional to the content of organic carbon in ore and pyrite. Passing from striped fine-grained pyrite ore to massive coarse-grained pyrite ore, i.e. from south to north, the sulphur isotopic composition changes from the light sulphur-enriched one to the heavy sulphur-enriched one. The lead isotopic composition of striped ore is consistent with that of the country rocks of orebodies and the lead is radiogenic lead derived from the upper crust. The lead isotopic composition of massive ore is relatively homogeneous and its 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios are a bit lo 相似文献
129.
本文用抽空石英管法对三元硫化物体系Ag_2S-PbS-Bi_2S_3和Cu_2S-PbS-Bi_2S_2的500℃相关系进行了研究。Cu_2S-PbS-Bi_2S_3体系的相图特征是Bi_2S_3-CuPbBiS_3。之间完全固溶关系,以及它与二元系Cu_2S-Bi_2S_3和PbS-Bi_2S_3各相之间双变关系。Ag_2S-PbS-Bi_2S_3体系相图被PbS-AgBi_S_2之间的完全固溶关系分成两部分:富铋与富银。富银部分仅有辉银矿与PbS-AgBiS_2固溶体之间简单双变关系,而富铋部分却包含丰富的银、铅铋硫盐。在抽空石英管法500℃下合成成功的有块硫铋银矿固溶体、铜银铅铋矿、硫铋铅矿固溶体、富硫铋铅矿和辉铅铋矿。 以上两个体系中矿物之间共生长关系及稳定范围也作了简短讨论。 相似文献
130.
在白云鄂博地区发现的水磷钙钍石呈脉状产于元古代变质石英砂岩中,共生矿物有透辉石、金红石、磷灰石、重晶石、赤铁矿和黄铁矿等。颜色从浅黄色到红褐色乃至黑色,从透明至半透明以至不透明。红褐色水磷钙钍石为玻璃光泽,比重3.42,摩氏硬度4.28—4.29,磁化率(2.34—3.99)×10~(-6)C·G·S·m cm~3/g,平均折光率No=1.65,Ne=1,66,一轴晶(+)。 水磷钙钍石的化学式为:(Ca_(0.5751)Th_(0.4502)U_(0.0070)La_(0.0030))_(1.0353)(P_(0.7578)S_(0.0928))_(0.8506)O_4(CO_3)_(0.1603),0.9H_2O。六方晶系,晶胞参数a=6.94A,c=6.51A。 相似文献