Theoretical research on intensity envelope function of strong ground motion     

金星  瘳振鹏 《地震学报(英文版)》1994,7(4):637-644

（金星，瘳振鹏）Ｔｈｅｏｒｅｔｉｃａｌｒｅｓｅａｒｃｈｏｎｉｎｔｅｎｓｉｔｙｅｎｖｅｌｏｐｅｆｕｎｃｔｉｏｎｏｆｓｔｒｏｎｇｇｒｏｕｎｄｍｏｔｉｏｎ￥ＸｉｎｇＪＩＮａｎｄＺｈｅｎ－ＰｅｎｇＬＩＡＯ（ＩｎｓｔｉｔｕｔｅｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈ...  相似文献   

CHARACTERISTICS OF TURBULENCE SPECTRA IN DIFFERENT WEATHER PROCESSES UNDER UNSTABLE CONDITIONS^*          下载免费PDF全文

Zhu Wenqin  Zhu Cuijuan  Li Xingsheng 《Acta Meteorologica Sinica》1994,8(3):296-304

In this paper,the data chosen from measurements by supersonic anemometers in Tongxian County of Beijing in 1990 are used to study characteristics of turbulence spectra in precipitation weather.Some turbulence parameters such as turbulence intensity,heat and momentum fluxes,friction velocity,M-O length and stability parameter are calculated and their dependence on turbulence spectra in different stability conditions are analyzed.Some encouraging results are obtained and compared with others' results.  相似文献   

Petroleum isoprenoid hydrocarbons derived from catagenetic degradation of archaebacterial lipids     

J. Albaigés  J. Borbón  W. Walker 《Organic Geochemistry》1985,8(4):293-297

The three GC coeluting C₄₀ bis-phytanes with head-to-tail, tail-to-tail and head-to-head linkages considered to be archaebacterial markers, have been recognized in petroleum by enhanced mass-fragmentography. Supporting evidence has been obtained by the simultaneous occurrence of two C₂₁–C₂₄ series of isoprenoid and quasi-isoprenoid hydrocarbons that are supposedly formed during the catagenetic degradation of the isomeric C₄₀ isoprenoids. The C₂₁–C₂₄ quasi-isoprenoid hydrocarbons have been identified conclusively for the first time by comparison with authentic standards.  相似文献   

Contact-metamorphic effect on parameters for kerogen maturation     

Yoshihiro Uji 《Organic Geochemistry》1986,9(6)

This study examines the effect of contact metamorphism by an igneous dyke on parameters for kerogen maturation, such as elemental composition (H/C, O/C, N/C), ¹H-NMR T₁, vitrinite reflectance and infrared spectra. Although elemental composition and ¹H-NMR T₁ of the kerogen changed only within 1.5 and 5.0 m from the dyke respectively, vitrinite reflectance of the kerogen was thermally affected beyond 10.0 m from the intrusion. It is concluded that vitrinite reflectance is the most sensitive of the parameters evaluated to assess thermal stress of kerogens.  相似文献   

内蒙赤峰莲花山金矿田石英脉的红外光谱成矿信息及定量预测     

郭树平  张培萍  孙本龙  王自杰 《吉林大学学报(地球科学版)》1995,(4)

测试了１３０余件含金石英脉及不含金石英脉的红外光谱试样，查明了该区含金石英脉的红外光谱特征，同时配合其它预测含金石英脉的测量方法，提出了该区含金石英脉的预测靶区，经过初步验证，预测基本上是准确的。  相似文献   

水文时间系列周期分析方法探讨   总被引：15，自引：2，他引：15  

易淑珍  王钊 《水文》2005,25(4):26-29

以分析广东省降水周期变化规律为例，探讨了最大熵谱方法在提取水文时间系列的主次周期上以及小波变换方法在分析水文时间系列的多时间尺度演变规律上的应用。由计算结果分析得到广东省降水过程主要存在的周期特性和旱涝变化趋势，为广东省降水趋势预测提供了重要信息。  相似文献   

钢筋混凝土框架结构抗震超强系数分析   总被引：1，自引：0，他引：1  

周靖  蔡健  方小丹 《世界地震工程》2007,23(4):227-233

基于我国建筑抗震规范要求设计的14栋代表不同抗震特征要求的多高层规则钢筋混凝土框架，通过静力弹塑性分析详细地评估了框架结构的体系超强能力。分析中采用与抗震规范等效静力地震作用效应分布模式相同的单调递增侧向荷载，以二维平面框架为分析对象。分析结果表明地震分区对超强系数的影响较大；有填充墙框架比无填充墙框架的超强能力明显要大；内框架的超强能力比外框架的超强能力大；超强系数随框架楼层数的增加而减小。  相似文献   

Study on inelastic displacement ratio spectra for near-fault pulse-type ground motions   总被引：2，自引：1，他引：2  

翟长海  李爽  谢礼立  孙亚民 《地震工程与工程振动(英文版)》2007,6(4):351-355

In displacement-based seismic design, inelastic displacement ratio spectra (IDRS) are particularly useful for estimating the maximum lateral inelastic displacement demand of a nonlinear SDOF system from the maximum elastic displacement demand of its counterpart linear elastic SDOF system. In this study, the characteristics of IDRS for near-fault pulse-type ground motions are investigated based on a great number of earthquake ground motions. The in? uence of site conditions, ratio of peak ground velocity (PGV) to peak ground acceleration (PGA), the PGV, and the maximum incremental velocity (MIV) on IDRS are also evaluated. The results indicate that the effect of near-fault ground motions on IDRS are signifi cant only at periods between 0.2 s - 1.5 s, where the amplifi cation can approach 20%. The PGV/PGA ratio has the most signifi cant in? uence on IDRS among the parameters considered. It is also found that site conditions only slightly affect the IDRS.  相似文献   

Source mechanism and source parameters of May 28, 1998 earthquake,Egypt   总被引：1，自引：0，他引：1  

K. M. Abou Elenean  H. M. Hussein 《Journal of Seismology》2007,11(3):259-274

On May 28, 1998, a moderate size earthquake of mb 5.5 occurred offshore the northwestern part of Egypt (latitude 31.45°N and longitude 27.64°E). It was widely felt in the northern part of Egypt. Being the largest well-recorded event in the area for which seismic data from the global digital network are available, it provides an excellent opportunity to study the tectonic process and present day stress field occurring along the offshore Egyptian coast. The source parameters of this event are determined using three different techniques: modeling of surface wave spectral amplitudes, regional waveform inversion, and teleseismic body waveform inversion. The results show a high-angle reverse fault mechanism generally trending NNW–SSE. The P-axis trends ENE–WSW consistently with the prevailed compression stress along the southeastern Hellenic arc and southwestern part of the Cyprean arc. This unexpected mechanism is most probably related to a positive inversion of the NW trending offshore normal faults and confirms an extension of the back thrusting effects towards the African margin. The estimated focal depth ranges from 22 to 25 km, indicating a lower crustal origin earthquake owing to deep-seated tectonics. The source time function indicates a single source with rise time and total rupture duration of 2 and 5 s, respectively. The seismic moment (M _o) and the moment magnitude (M _w) determined by the three techniques are 1.03 × 10¹⁷ Nm, 5.28; 1.24 × 10¹⁷ Nm, 5.33; and 1.68 × 10¹⁷ Nm, 5.42; respectively. The calculated fault radius, stress drop, and the average dislocation assuming a circular fault model are 7.2 km, 0.63 Mpa, and 0.11 m, respectively.  相似文献   

Acceleration response modification factors for nonstructural components attached to inelastic moment‐resisting frame structures     

Ragunath Sankaranarayanan  Ricardo A. Medina 《地震工程与结构动力学》2007,36(14):2189-2210

A statistical analysis of the peak acceleration demands for nonstructural components (NSCs) supported on a variety of stiff and flexible inelastic regular moment‐resisting frame structures with periods from 0.3 to 3.0 s exposed to 40 far‐field ground motions is presented. Peak component acceleration (PCA) demands were quantified based on the floor response spectrum (FRS) method without considering dynamic interaction effects. This study evaluated the main factors that influence the amplification or decrease of FRS values caused by inelasticity in the primary structure in three distinct spectral regions namely long‐period, fundamental‐period, and short‐period region. The amplification or decrease of peak elastic acceleration demands depends on the location of the NSC in the supporting structure, periods of the component and building, damping ratio of the component, and level of inelasticity of the supporting structure. While FRS values at the initial modal periods of the supporting structure are reduced due to inelastic action in the primary structure, the region between the modal periods experiences an increase in PCA demands. A parameter denoted as acceleration response modification factor (R_acc) was proposed to quantify this reduction/increase in PCA demands. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献