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991.
Bang-Fuh CHEN 《中国海洋工程》2007,21(4):659-675
In multiresolution analysis(MRA)by wavelet function Daubechies(db),we decompose the signal to two parts,the low and high frequency content.The high-frequency content of the data is removed first and a new "de-noise" signal is reconstructed by using inverse wavelet transform.The wavelet spectrum and harmonic analysis were used to analyze the characteristics of tidal data before constructing the input and output structure of ANN model.That is,the concept of tidal constituent phase-lags was introduced and the new "de-noise" signal was used as the input data set of ANN and the forecasting accuracy of ANN model is significantly improved. 相似文献
992.
993.
994.
Taiwan is a typical active orogenic belt situated at the collision boundary between the Eurasian Continental Plate and the Philippine Sea Plate. Dissolved major and trace constituents, as well as Sr and Sr isotopes in river waters collected from the Danshuei River basin in northern Taiwan have been studied to evaluate chemical weathering processes. The results of principal component analysis show that the ion sources in these river waters can be categorized into 3 major components: chemical weathering, seasalt contribution and local anthropogenic input. The chemical weathering is the most dominant factor that contributes about 85% of total variances. Significantly increased Na/Cl and Ca/Cl, as well 87Sr/86Sr, were observed in most upper stream samples. The Na/Cl and Ca/Cl ratios in the Dahan Stream, however, are much higher than the Shindien Stream. Even though average rainfall is stronger in the Shindien drainage basin, chemical evidence from river waters supports less intense weathering in the region. Selective dissolution of secondary calcites explains the observed high Ca/Cl, Sr/Cl and Ca/Na in the Dahan Stream. These results highlight the potential importance of tectonic factors, such as uplift and physical erosion in studying chemical weathering in an active orogenic belt. 相似文献
995.
The 1975 Haicheng MS7.3 earthquake affected whole Korean Peninsula and even Kyushu,Japan.In this paperisoseismal map of this earthquake was drawn for these areas by sorting out and analyzing data systematically col-lected,furthermore,the characteristics of the earthquake damage were discussed.In the northern Korean Peninsula,the intensity is V in great majority of this area except local area with intensity VI,and the damage is basically inaccordance with typical characteristics of corresponding intensity grade.In the southern Korean Peninsula,theintensity is IV in large part of the area,however,in some big cities such as Seoul etc.,not only high buildingsshook strongly,but also some people appeared perceptions such as feeling dizzy and so on,and electrical servicewas interrupted on one or two districts because of transformer tripping.These phenomena could be caused by theeffect of long-period wave generated from a large earthquake on far-field. 相似文献
996.
Accurate estimation of the peak seismic responses of structures is important in earthquake resistant design. The internal force distributions and the seismic responses of structures are quite complex, since ground motions are multi- directional. One key issue is the uncertainty of the incident angle between the directions of ground motion and the reference axes of the structure. Different assumed seismic incidences can result in different peak values within the scope of design spectrum analysis for a given structure and earthquake ground motion record combination. Using time history analysis to determine the maximum structural responses excited by a given earthquake record requires repetitive calculations to determine the critical incident angle. This paper presents a transformation approach for relatively accurate and rapid determination of the maximum peak responses of a linear structure subjected to three-dimensional excitations within all possible seismic incident angles. The responses can be deformations, internal forces, strains and so on. An irregular building structure model is established using SAP2000 program. Several typical earthquake records and an artifi cial white noise are applied to the structure model to illustrate the variation of the maximum structural responses for different incident angles. Numerical results show that for many structural parameters, the variation can be greater than 100%. This method can be directly applied to time history analysis of structures using existing computer software to determine the peak responses without carrying out the analyses for all possible incident angles. It can also be used to verify and/or modify aseismic designs by using response spectrum analysis. 相似文献
997.
by Jianwei Song Yi-Lun Chu Zach Liang George C. Lee University at Buffalo State University of New York NY USA Erratum to: Earthq Engrg & Engrg Vib DOI: ./s---x 《地震工程与工程振动(英文版)》2007,6(2):213-213
We have found some mistakes in the article by Jianwei Song et al. (2007). The revisions arc given below: 1. "NEHRP 2003" in Figs.8 and 9 should be changed to "BSSC 2003". 2. "Tsopelas" or "Tsopelas method" 相似文献
998.
简要介绍内蒙古自治区准格尔煤田高岭岩矿产资源的勘探方法,并通过高岭岩矿层在测井曲线上的反映,分析运用测井成果进行高岭岩普查找矿工作的可行性。根据工作区以往271个钻孔的测井资料及所施工8个钻孔的钻探成果,共解释高岭岩矿层361层,其中可靠达170层。通过测井成果与钻探成果、化验资料对比统计可知,其高岭岩层真厚度量测井解释厚度的80%。 相似文献
999.
全球气候变暖背景下登陆我国台风特征的分析 总被引:38,自引:4,他引:38
利用1949-2002年西北太平洋热带气旋、登陆我国台风和全球地面温度资料,对登陆我国台风的频数、强度以及登陆位置的年际变化,特别是趋势特征进行了分析,并与西北太平洋台风的变化特征作了对比。结果表明:在全球气候变暖背景下,我国登陆台风频数的减少趋势没有西北太平洋台风频数的减少趋势强;登陆台风的平均强度和极端强度均有减弱趋势,极端强度的减弱趋势尤为明显,但其强度弱于西北太平洋台风。在1968-2002年全球明显增暖时段,我国台风登陆位置偏向我国中部,西北太平洋台风在生命史中强度达最强时的位置有向北移动的趋势。 相似文献
1000.
铜官山铜矿床矽卡岩矿物中流体包裹体及子矿物的扫描电镜研究 总被引:6,自引:2,他引:6
通过对安徽铜官山铜矿矽卡岩矿物中的流体包裹体岩相学、包裹体显微测温分析及子矿物的扫描电镜/能谱分析(SEM/EDS)和激光拉曼探针分析(LRM),发现石榴石、透辉石中的包裹体为流体包裹体,包裹体的均一温度(575~885℃)、盐度[w(NaCleq)13.4%~44.9%]均较高,流体包裹体中的子矿物有黄铜矿、闪锌矿、方解石、菱铁矿、钾石盐和石盐,以钾石盐最为普遍,表明流体高度富钾,具岩浆热液的典型特征。富钾流体也与该区广泛出露的燕山期高钾富碱岩体吻合。 相似文献