伊通地堑下第三系原油和生油岩中芳构化五环三萜及其地球化学意义     

兰文波  张英歧 《地球化学》1997,26(6):33-46

详细研究了吉林伊通地堑下第三系生油岩和原油中的芳烃生物标志物，包括常规的多环芳烃，以及丰富的来源于高等植物的芳香二萜和芳构化的五环三萜。目前，原油中芳构化五环三萜类生物类生物标志物国内外均尚报道极少。还详细讨论了利用原油中最新发现的芳构化五环三萜在解决本区生物输入，油源对比以及石油成因等方面的重要意义。  相似文献   

Barotropic local instability and severe storm process     

Dasheng Yang  Lan Sun 《中国科学D辑(英文版)》1997,40(3):259-268

By means of barotropic model, the characteristic and initial value problems are investigated to reveal the local two-dimensional barotropic instability of the nonuniform current to the dynamic mechanism of the formation of the Yangtze-Huaihe River severe storm in July 1991. Analytical theory and numerical experiment show that (i) the unstable developing modes are chiefly the two periods of about 44 d and 10 d, which are fundamentally consistent with that of the precipitation change of the Yangtze-Huaihe River. (ii) The growth rate of the local perturbation is dominated by the meridional wave numbern = 1–5 and zonal wave numberk = 1–12, i.e. the severe storm over the Yangtze-Huaihe River results from the interaction of the systems at different latitudes and waves of different scales, (iii) The perturbation over the Yangtze-Huaihe River possesses the property of local intensification, which slowly migrates westward over the lower and middle reaches of the Yangtze-Huaihe River. (iv) The growth rate of the instability, especially the propagation velocity of the perturbation, is sensitive to the external parameters ū and α. Project supported by the National Natural Science Foundation of China.  相似文献   

黄土的物理力学指标与黄土易损性分析研究   总被引：9，自引：1，他引：9       下载免费PDF全文

段汝文  王峻  李兰 《地震工程学报》1997,19(3):81-85

作者多年来在黄土地区进行了考察和勘探并采集了各类黄土样品，在室内外进行了黄土的物理力学性质的试验研究，取得了大量的关于黄土特性的资料．根据这些研究结果，探讨了黄土的物理力学指标与黄土易损性的关系及其区域分布规律，从而研究它与黄土地区的地质灾害和震害的关系．  相似文献   

黄河上游径流预报的灰色拓扑方法   总被引：5，自引：6，他引：5  

蓝永超  杨文华 《冰川冻土》1997,19(4):308-311

以龙羊峡水库年平均入库流量预报为例，根据灰色系统理论的建模方法，利用龙羊峡水库入库水量代表站唐乃亥水文站的实测径流资料，建立了一个ＧＭ（１，１）拓扑预测模型，用于黄河上游径流的长期预报，并取得了较为满意的结果。  相似文献   

An experimental study on seismic responses of multifunctional vibration‐absorption reinforced concrete megaframe structures     

Zongjian Lan  Yuji Tian  Liang Fang  Shuting Liang  Xinde Wang 《地震工程与结构动力学》2004,33(1):1-14

Two models are tested on a shake‐table. One of the models is a normal reinforced concrete megaframe structure and the other is a multifunctional vibration‐absorption reinforced concrete megaframe structure in which the laminated rubber bearings are placed between the major frame and the minor frames. Two earthquake motions (the El Centro wave and the Taft wave) are used during the test. This paper presents the dynamic characteristic, the seismic responses and the failure mechanism of these two models under varying peak acceleration levels for each of the earthquake motions. The test results demonstrate that the aseismic behavior of a multifunctional vibration‐absorption reinforced concrete megaframe structure is much better than that of a normal reinforced concrete megaframe structure. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

雷电监测预警系统的原理及应用          下载免费PDF全文

沐俊山  雷治平  张存华 《山西气象》2004,(4):24-26

本文讨论了有关雷电的基本知识，列举了目前存在的各种雷电定位方法，分析了雷电定位的几个过程。对近期引进VAISALA公司的SAFIR3000型雷电监测预警系统采用的探测原理做了分析，并总结了这套探测系统采用的VHF干涉测量原理特点及不足之处。  相似文献   

李坝金矿床金的赋存状态与选矿工艺学     

于岚  张复新  程彧 《矿产与地质》2004,18(1):86-89

李坝大型金矿床是产于西秦岭上古生代沉积岩系中类卡林型金矿床典型代表。通过显微镜及选矿实验查定了李坝金矿床金的赋存状态，矿床金矿物呈微细粒多种独立矿物出现，金的赋存形式多样，显示多期多阶段成矿特点，成为划分类卡林型金矿的重要参考。矿石工艺学的研究对工业选矿有指导意义。  相似文献   

建筑物沉降规律的综合时序分析   总被引：6，自引：0，他引：6  

崔晓东  兰孝奇  张兵良 《现代测绘》2004,27(1):36-38

建筑物的沉降监测数据序列具有趋势变化和随机变化的特点，本文针对两种变化项的特点分别建立相应的数学模型，再将其组合起来建立综合数学模型，从总体上把握沉降数据序列的变化规律。实例计算分析表明，此方法具有较高的拟合精度和预测能力，具有一定的应用参考价值。  相似文献   

Geochemical and Sr-Nd isotopic study of alkaline syenites in Liangtun-Kuangdonggou, Liaoning Province, China： Evidence for enriched mantle before 1.86 Ga and implications     

任康绪  阎国翰  蔡剑辉  牟保磊  李凤棠  古丽冰  赵凤三  储著银 《中国地球化学学报》2005,24(3):232-242

The 1.86 Ga Liangtun-Kuangdonggou complex (LKC) is one of the oldest alkaline syenite bodies so far discovered in China. This syenite suite has elevated contents of total alkali (K2O Na2O), with an average of 10.50%, and a mean Rittmann Index (σ) of 6.48. The intrusions have slightly higher concentrations of K2O than those of Na2O on a weight percent basis, indicating the rocks belong to potassium-rich alkaline syenite series. Total rare-earth element concentrations (∑REE ) of the rocks are relatively high, ranging from 324×10 -6 to 1314×10 -6, with a mean value of 666×10 -6. The REE patterns are subparallel and rightward steep with (La/Yb)N >33, showing mild negative to positive Eu anomalies (δEu: 0.63-1.15). All samples exhibit strong LILE and LREE enrichments and TNT (Nb, Ta, Ti) and P depletions in multi-element spidergrams. On the εSr(t)-εNd(t) correlation diagram, most analytical data points plot within the enriched mantle field with low ( 87Sr/86Sr)i ratios (0.7045-0.7051) and negative εNd(t) values (-3.72--3.97), falling among those kimberlites from Fuxian County, Liaoning Provinve, from Mengyin County, Shandong Province and the Ⅱ-type kimberlites from South Africa. These characteristics imply that the LKC-rocks may have the same source as the above-mentioned kimberlites, i.e., they have close connections to the materials derived from enriched mantle reservoirs, further revealing that the upper mantle beneath the northeastern part of the North China Plate had been highly enriched before 1.86 Ga. Geodynamically, the LKC-rocks were formed in a within-plate environment with close genetic connections to rift-related alkaline magma activities possibly controlled by ancient mantle plumes.  相似文献   

Dynamic characteristics analysis of shallow landslides in response to rainfall event using GIS     

H. X. Lan  C. F. Lee  C. H. Zhou  C. D. Martin 《Environmental Geology》2005,47(2):254-267

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