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1.
基于阿克苏河上游高山区采集的雪岭云杉树轮样芯构建了雪岭云杉树轮宽度年表,结合阿克苏河干流径流数据解析了雪岭云杉长期生长与阿克苏河干流径流关系,并重建了阿克苏河干流1813—2015年冬季径流序列。结果表明:利用雪岭云杉树轮宽度年表重建的阿克苏河干流1813—2015年冬季径流序列模拟值与实测值吻合度较高,重建径流序列稳定可靠;1813—2015年阿克苏河干流冬季多年平均流量为82.19 m~3/s,共出现5次持续丰水期和3次持续枯水期,最长的枯水段持续17年(1943—1959年);阿克苏河干流冬季径流变化存在51 a、29 a、16 a周期,第一主周期为51 a。  相似文献   
2.
The statistical process of seriation arranges a set of objects along a one-dimensional line so that the distance between each pair of objects reflects the dissimilarity between them. The process has recently been cast into an algorithm which makes it feasible to seriate a few tens of objects efficiently on a personal computer. This algorithm is now used for establishing a chronology of the Troubadours according to certain melodic features in their works. Other musicological uses for seriation are proposed.David Halperin is a Lecturer in the Department of Musicology, Tel Aviv University, specializing in computer-aided analysis of monophonic music. He has published articles on the Ambrosian chant and on the ancient musical notation from Ugarit. His publications include A Segmentation Algorithm and its Application to Medieval Monophonic Music,Musikometrika, 2 (1990) and Towards Deciphering the Ugaritic Musical Notation,Musikometrika, 4 (1992).This is an expanded version of a paper given at the 15th Congress of the International Musicological Society, Madrid, 1992.  相似文献   
3.
Accumulation of Ot alternative antifoulants in sediment is the focus of this research. Much research had been done on surface sediment, but in this report, the accumulation in the sediment core was studied. The Ot alternative antifoulants, Diuron, Sea-Nine211, and Irgarol 1051, and the latter’s degradation product, M1, were investigated in five samples from the northern part of Hiroshima Bay. Ot compounds (tributyltin (TBT) and triphenyltin (TPT)) were also investigated for comparison. In addition, metal (Pb, Cu, Zn, Fe and Mn) levels and chronology were measured to better understand what happens after accumulation on the sea floor. It was discovered that Ot alternative antifoulant accumulation characteristics in sediment were like Ot compounds, with the concentration in the sediment core being much higher than surface sediment. The concentration in sediment seems to have been affected by the regulation of Ot compounds in 1990, due to the concentration of Ot alternative antifoulants and Ot compounds at the survey point in front of the dock, showing an increase from almost the same layer after the regulation.  相似文献   
4.
Incompatible land use is a major contributor to ecosystem degradation, and is often exacerbated by climate change impacts. We investigate Lake Basotu, Tanzania as a case study where natural lake variability has been affected by agricultural land use. Comparisons between a satellite-derived history of lake surface area, local precipitation records, and corresponding anthropogenic activity show the impacts of agricultural and historical practices. We argue that insufficient consideration to the wider ecological impacts of large agricultural projects has lasting implications. This is particularly true in semi-arid environments where food production demands need to be continuously met. In the future, major conservation strategies should be investigated to maintain the environmental integrity and sustainability of freshwater resources.  相似文献   
5.
新疆阿尔泰南缘北塔山组火山岩较为发育。本文对新疆阿尔泰南缘默色克奥依一带北塔山组火山岩进行地球化学分析和年代学研究。研究表明:U-Pb锆石年龄为(384.3±4.0Ma)Ma,为中泥盆世;该组火山岩属于钾质钙碱性系列,全碱(Na2O+K2O=2.07%-6.49%)和YiO2(0.24%-0.64%)含量较低,K2O含量(1.11%-4.04%)变化较大,稀土元素含量(∑REE)较低。稀土元素显示其轻稀土富集且分馏不明显;δEu值均大于1,为Eu富集型;δCe值均小于1,为Ce亏损型。该组火山岩微量元素P明显富集,K、Rb、Ba等大离子亲石元素(LILE)略富集,亏损Ta、Zr、Hf、Ti等高场强元素(HISF)。结合前人研究,本文认为默色克奥依一带北塔山组火山岩形成于岛弧及与俯冲过程有关的活动大陆边缘造山带环境,为泥盆纪古大洋俯冲消减过程中,俯冲板片脱水产生的流体交代上覆地幔楔部分熔融的产物。  相似文献   
6.
William Faulkner's non-chronological story tellingstyle has long been a challenge to critics and apuzzle to beginning literature students. ``A Rose forEmily,' one of Faulkner's most frequently anthologizedstories, exemplifies the complexity of Faulkner'streatment of time. In this paper, we apply aconstraint-based problem solving method to an analysisof the chronology of ``A Rose for Emily.' Constraintlogic programming is a declarative programminglanguage paradigm that solves problems by enforcingconstraints among variables. CLP's ability to sortnumeric variables that do not yet have definite valuesmakes it possible to sort the events of ``A Rose forEmily' with only fragmented and relative timeinformation. In attempting to sort the events of thestory, we find an inconsistency in the temporalreferences scattered throughout the narrative. Afterremoving this inconsistency, we are able to compareour chronology with earlier ones and discuss thethematic relevance of Faulkner's nonlinear plots.  相似文献   
7.
对藏南扎西康锌多金属矿床辉绿岩进行锆石U-Pb年代学,岩石地球化学特征研究。研究发现藏南扎西康矿区内辉绿岩锆石U-Pb年龄为(132.9±2.4)Ma,与区域上喜马拉雅带中早白垩世基性岩共同组成了一套同时代产出的基性火成岩群。岩石地球化学研究中,Zr/Nb-Y/Nb和Zr-Y图解显示辉绿岩成岩物质来自富集地幔,而Zr/Ba=1.4614.57和LILE的弱亏损表明有亏损地幔的特点。扎西康辉绿岩形成于早白垩世新特提斯洋形成后,大陆被动边缘伸展,大陆地壳拉张减薄的动力学背景,拉张过程中可能发生了软流圈上涌导致岩浆从富集地幔向亏损地幔过渡。  相似文献   
8.
鲁肃 《中国水利》2006,(17):57-58
《地方志工作条例》颁分布施行后,水利史志编纂工作面临新的发展机遇,河南省水利史志工作者应适应方志工作新形势,研究水利史志工作新任务,以创新的姿态拓展水利史志的新空间,使水利史志工作向多元化方向发展,以文化的力量推动河南水利事业的发展。  相似文献   
9.
三通沟海相沉积型锰矿是近年来东昆仑地区锰矿找矿工作的新突破。对三通沟锰矿中两件粉砂岩样品进行LA-ICP-MS碎屑锆石U-Pb定年,获得年龄为(1 497±17)~(427±4)Ma,主要集中在441和473 Ma两个峰值附近,最年轻的碎屑锆石年龄为(427±4)Ma,表明其沉积时代晚于427 Ma,并且指示其沉积物质来源于纳赤台群中段。三通沟锰矿黑色页岩Re-Os等时线年龄为(387.4±6.2)Ma,表明其成矿作用中成岩转化过程的时间为中泥盆世,而锰质的初始沉淀早于这个时间。综合同位素定年结果,将三通沟锰矿的沉积时代限定在晚志留世—中泥盆世。结合早古生代海相沉积型锰矿矿床成因的主流观点,探讨三通沟锰矿的成矿作用与原特提斯洋俯冲作用之间的关系,认为早古生代原特提斯洋的俯冲闭合是三通沟锰矿成矿的主要原因,三通沟锰矿的成矿时代与原特提斯洋闭合时间基本一致。  相似文献   
10.
赤峰阿贵浑德伦铅锌矿是黄岗梁—甘珠尔庙成矿带上新发现的矿床,成矿与花岗岩类关系密切。矿区出露的花岗岩主要为黑云母花岗岩和花岗斑岩,对黑云母花岗岩的LA-ICP-MS锆石U-Pb测年结果显示其形成年龄为(130.6±1.0)Ma(MSWD=0.095),为早白垩世岩浆活动产物,岩石地球化学测试结果显示黑云母花岗岩与花岗斑岩特征具有一致性,均具有高硅(SiO_272.55%~78.22%)、富碱(Na_2O+K_2O 4.48%~878%)、贫P_2O_5的特征,A/CNK在1.32~2.79之间,属过铝质岩石,富集微量元素K、U、Th、Rb、Pb,亏损Ba、Sr、P、Ti,10000Ga/Al比值高(2.49~3.59),表现出A型花岗岩典型的地球化学特征。稀土元素含量较高,相对富集LREE,花岗岩稀土元素呈右倾海鸥型配分模式,负Eu异常明显,δEu为0.10~0.48,表明花岗岩在成岩过程中分异出了斜长石。花岗岩Sr、Yb含量分别为(31.91~185.01)×10~(-6)、(217~6.18)×10~(-6),属低Sr高Yb型花岗岩。阿贵浑德伦铅锌矿花岗岩类与大兴安岭地区锡多金属成矿花岗岩的年代学及地球化学特征均十分相似,指示了该区除铅锌矿外还具有锡矿的找矿前景。  相似文献   
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