结构地震反应时程分析中的阻尼问题评述   总被引：22，自引：5，他引：22  

黄宗明  白绍良 《地震工程与工程振动》1996,16(2):95-105

本文对一般建筑结构地震反应时程分析，主要是弹塑性时程分析中阻尼问题的研究现状进行了分析介绍，指出了存在的问题，并就解决这些问题的关键提出了作者的看法。  相似文献   

SUSTAIN RESERVOIR USEFUL LIFE BY FLUSHING SEDIMENT     

Hsieh Wen Shen  Jihn-Sung Lai 《国际泥沙研究》1996,(3)

ＳＵＳＴＡＩＮＲＥＳＥＲＶＯＩＲＵＳＥＦＵＬＬＩＦＥＢＹＦＬＵＳＨＩＮＧＳＥＤＩＭＥＮＴ￥ＨｓｉｅｈＷｅｎＳｈｅｎａｎｄＪｉｈｎ－ＳｕｎｇＬａｉ（Ｐｒｏｆｅｓｓｏｒ，ＵｎｉｖｅｒｓｉｔｙｏｆＣａｌｉｆｏｒｎｉａａｔＢｅｒｋｅｌｅｙ，Ｄｅｐａｒｔｍｅｎ...  相似文献   

对ETALON卫星的精密定轨研究   总被引：3，自引：1，他引：3  

冯初刚  谭德同  朱元兰  张忠平 《测绘学报》1997,26(2):109-116

ＥＴＡＬＯＮ卫星是１９８９年发射的激光卫星，具有正球形、高质面比和轨道近圆等特点。其轨道倾角６５°，半长径为２．５万ｋｍ。其轨道不仅稳定，而且优化了覆盖欧亚大陆及太平洋地区的几何特性，适合于测定地球自转参数，更适合于全球测地和地壳运动的研究。本文研究了对Ｅ－ＴＡＬＯＮ卫星精密定轨的要求，如摄动模型的选取，数值积分中积分步长的选取等，利用１９９４年１０月ＥＴＡＬＯＮ－２的资料，对ＥＴＡＬＯＮ－２卫星进行了精密定轨，一个月（３１ｄ）弧长的定轨精度优于１０ｃｍ，１０天弧长定轨精度优于５ｃｍ。  相似文献   

内蒙白旗地区火山碎斑熔岩斜长石成分及其有序度   总被引：1，自引：0，他引：1  

赖绍聪  隆平 《西北地质》1997,18(3):8-12

白旗碎斑熔岩中斜长石以更长石为主，其有序度低，指示了岩石高温火山成因的特征，从岩体边缘相到中心相至根部相，长石类型，化学成分和有序度具有一定的变化规律，反映了岩体不同岩相带成岩条件的差异性。  相似文献   

南秦岭勉县—略阳结合带变质火山岩岩石地球化学特征   总被引：22，自引：4，他引：22  

赖绍聪  杨永成 《岩石学报》1997,13(4):563-573

勉县－略阳结合带变质火山岩以基性和中基性岩石为主体，见有少量英安质火山岩。可区分为两种岩石－构造组合类型：一类为低钾高钛、轻稀土亏损的拉斑玄武岩，Ｔｉ／Ｖ、Ｔｈ／Ｔａ、Ｔｈ／Ｙｂ、Ｔａ／Ｙｂ表明其应属于ＭＯＲＢ型玄武岩；另一类为岛弧火山岩组合，以钙碱性安山岩类为主体，并有少量岛弧拉斑玄武岩类。  相似文献   

Nonlinear impacts upon frontal cyclones from dipole surface temperature anomalies     

Prof. R. Grotjahn  Sy-Shiann Lai 《Meteorology and Atmospheric Physics》1991,45(3-4):159-180

Summary The effects of surface temperature anomalies (STAs) upon frontal cyclones are investigated with a nonlinear model. The model used is a modified version of the NCAR Community Climate Model (CCM 1). The experiments are run with hemispheric domain and R 30 (rhomboidal) truncation. The present study isolates the effects of sensible heating. Topography and latent heating are excluded from this model. The initial data are created from a solution (normal mode) to the linear eigenvalue problem. Six experiments use various locations and intensities for dipole-shaped STA; one control case is run without STA. The intensity is either ±5 or ±10°K and the anomalies ae located at 40°N, 50°N, or 35°N. The jet is centered at 40°N. All cases are run for 20 days. Nonlinear, time-dependent, growth rate and phase frequency are derived and compared to the linear (eigenvalue) amounts.The resulting waves grow primarily by baroclinic instability. Perturbation fields at higher levels grow faster before they mature (occlude) and decay faster afterward, than do lower level fields. The baroclinic conversion of energy lessens as the perturbations mature. The principal hypothesis tested is that: the STA alters the static stability which in turn modulates the baroclinic instability. Over warm anomalies the static stability should be reduced, enhancing baroclinic instability. Over cold anomalies the opposite may happen. The nonlinear simulations confirm this hypothesis in part. In the present study, the intensity of the warm anomaly produces greater growth rate during and after the storm's mature state. Larger STA intensity increases the maximum amplitude of the perturbation in a roughly linear fashion. However, the STA effects are nonlinear after maximum amplitude is reached: during decay, the difference in amplitude between the control case and the 10°K STA case is more than twice the difference between the control and 5°K case. In contrast, little deviation from the control case is found for perturbations over the cold anomaly, indicating a nonlinear link between STA and wave growth. The latitudinal variation used of the surface temperature anomaly centers had no significant influence on the baroclinic growth. Secondary growths of storms after 10 days are more commonly seen in cases with STA.  相似文献   

Effects of parameter variability on length-cohort analysis     

Lai  Han-Lin; Gallucci  Vincent F. 《ICES Journal of Marine Science》1988,45(1):82-92

  相似文献   

铁山港湾生原要素的变化特征及其影响因素   总被引：3，自引：1，他引：3  

韦蔓新  童万平  赖廷和  何本茂 《海洋湖沼通报》2001,(4):23-27

本文根据1999年12月的调查资料，分析探讨了广西沿海东部东部铁山港湾生成要素的变化特征及其影响因素。结果表明：本水域生原要素含量不高，与相邻的北海湾相比略低，但与1984年岸调的结果相比，N和Si呈上升趋势，P则呈下降趋势，N以陆源输入影响为主，而P和Si则以有机体分解的再生过程影响为主。  相似文献   

CO<Subscript>2</Subscript>-rich fluid inclusions with chalcopyrite daughter mineral from the Fenghuangshan Cu–Fe–Au deposit,China: implications for metal transport in vapor     

Jianqing Lai  Guoxiang Chi 《Mineralium Deposita》2007,42(3):293-299

CO₂-rich fluid inclusions containing opaque mineral crystals were found in the Fenghuangshan skarn-porphyry Cu–Fe–Au deposit in Tongling, Anhui, China. These inclusions show variable CO₂ contents and are accompanied by aqueous inclusions, both occurring as secondary inclusions in quartz and being locally associated with chalcopyrite mineralization. Laser Raman microspectroscopic analyses confirm the predominance of CO₂ in the vapor and the presence of H₂S as high as 8 mol%, and identify the opaque mineral with yellow reflectance color in the inclusions as chalcopyrite. More than half of the CO₂-bearing inclusions contains chalcopyrite, whereas few of the associated aqueous inclusions do so. The chalcopyrite, occupying less than 1% (volume) of the inclusions, is interpreted to be a daughter mineral, and calculated Cu concentrations in the inclusions range from 0.1 to 3.4 wt%. Copper is inferred to have been transported in CO₂-dominated fluids as HS⁻ complexes. The occurrence of chalcopyrite daughter crystals in CO₂-rich fluid inclusions indicates that CO₂-rich vapor has the capacity of transporting large amounts of Cu, and possibly Au. This finding has significant implications for metal transport and mineralization in hydrothermal systems enriched in CO₂, such as orogenic-type and granitic intrusion-related gold deposits.  相似文献   

The prelude of the end-Permian mass extinction predates a postulated bolide impact     

Hongfu Yin  Qinglai Feng  Aymon Baud  Shucheng Xie  Mike J. Benton  Xulong Lai  David J. Bottjer 《International Journal of Earth Sciences》2007,96(5):903-909

The mass extinction at the Permian–Triassic Boundary (PTB) is said to have been abrupt and probably caused by an extraterrestrial impact. However, evidence from the Global Stratotype Section and Point (GSSP) of the base of the Induan at Meishan, China, shows that the biotic crisis began prior to the level, in beds 25 and 26 at which the postulated impact event occurred. Evidence of such an earlier biotic crisis occurs in other sections in South China, and in central and western Tethyan regions. This event is characterized by the extinction of a range of faunas, including corals, deep-water radiolarians, most fusulinids and pseudotirolitid ammonoids, and many Permian brachiopods. In all sections, this extinction level is usually a few decimeters to meters below that of the main mass extinction in the event beds (25 and 26) at Meishan, and their correlatives elsewhere. This earlier extinction event happened before the postulated bolide impact at the level of beds 25 and 26, and constrains interpretation of the mechanisms that brought about this greatest mass extinction. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.  相似文献