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31.
P. Triantafyllidis P. M. Hatzidimitriou P. Suhadolc N. Theodulidis A. Anastasiadis 《Pure and Applied Geophysics》2004,161(5-6):1205-1219
— To check the reliability and the quality of the theoretically estimated ground responses obtained from the 2-D simulation by the application of the hybrid method in PART-I, we compare some of them with those obtained at the same sites from observed data using the Standard Spectral Ratio (SSR). The comparison validates our synthetic modeling and shows that in cases of complex geometries, the use of at least 2-D numerical simulations is required in order to reliably evaluate site effects and thus facilitate the microzonation of the city of Thessaloniki. 相似文献
32.
通过对深层水泥土搅拌桩的加固机理及复合地基承载力性状的简要分析,根据国家现行规范,结合具体地基处理工程实例,对深层水泥搅拌桩在软土地区地基加固处理中的方案选择、设计、施工及检测中的常见技术要点作初步探讨。 相似文献
33.
Micrometeorological data for wind and temperature from a 325 m high tower in Beijing City are analyzed by use of local similarity theory. Non-dimensional wind and temperature gradients, Фm and Фh, are determined by three techniques called, respectively, eddy-correlation, mean profiles and inertia-subrange cospectra (ISC) method for a wide range of atmospheric stratification from unstable to stable conditions. Average dissipation rate Фε of turbulent kinetic energy (TKE) is evaluated from u-spectrum, as a quantity required in the last technique. Ratio of the eddy transfer coefficients. α (= Kh / Km,), is calculated from Фm and Фh estimations. The results from various techniques are compared with each other and with some available empirical results in the tower-layer. It is shown that the empirical relationships determined by mean profiles and ISC methods in the tower-layer turbulence are in agreement with each other and with some other results. 相似文献
34.
Micrometeorological data for wind and temperature from a 325 m high lower in Beijing City are analyzed by use of local similarty
theory Non–dimentional wind and temperature gradients Φ and Φ are determined by three techniques called respectively, eddy-correlation,
mean profiles and inertia subrange cospectra (ISC) method for a wide range of atmospheric stratification from unstable to
stable condition Average dissipation rate Φof turbulent kinetic energy (TKE) is evaluated from u-spectrum as a quanlity required in the last technique. Ratio of the eddy transfer coefficients. α(= K / K) is calculated from Φ and Φ estimations. The results from various techniques are compared with each other and with some available
empirical results in the lwor -layer. it is shown that the empirical relationship detefrmined by mean profiles and ISC methods
in the lower-layer turbulence are in agreement with each other and with some other results.
Supported by the National Natural Science Foundation of China under Grant No.49735170.
The authors are very grateful to the members, working for the State Key Lab. of Atmospheric Boundary Layer Physics and Atmospheric
Chemistry, the Institute of Atmospheric Physics in Beijing, who supplied the data from the meteorological tower for this paper.
The authors wish to thank to Mrs. Israa H. A. in the presentation of data on the required style. 相似文献
35.
利用地下流体氦同位素比值估算大陆壳幔热流比例 总被引：12，自引：2，他引：10
地下流体中的氦同位素 3He来自地幔的排气作用 ,4He则是铀、钍衰变的产物 .由于铀、钍元素在大陆地壳中富集 ,4He通量与地壳热流呈正相关关系 ;同时 3He通量与地幔热流之间呈正相关 .所以地下流体的氦同位素比值 （3He / 4 He）与大陆壳幔热流比值 （qc/qm）呈反相关关系 .根据欧亚大陆和加拿大地盾的地下流体氦同位素比值数据和相应的壳幔热流比值数据 ,统计出 qc/ qm 与 3He / 4 He之间的回归关系 :qc/ qm =0 81 5- 0 30 0ln（3He / 4 He） ;此处 3He/ 4 He的单位是RA（大气的 3He/ 4 He比值 ） .有了地表热流值和壳幔热流比值即可得到地壳热流和地幔热流 .利用该公式以及热流值估算了中国主要盆地的壳幔热流值 ;根据这些数值得出的热岩石圈厚度和地壳平均生热率结果与地震学研究成果一致 .氦同位素比值是区分大陆热流中地壳热流值和地幔热流值的有用参数 . 相似文献
36.
通过对文安—蔚县—察哈尔右翼中旗深地震测深剖面S波资料的处理解释 ,获得本区二维壳幔速度结构和波速比结构。该区的上、中地壳主要由花岗岩组成 ,整体呈脆性 ,其速度比γ值为 1 72左右 ;下地壳的γ值一般为 1 78;上地幔顶部的γ值在 1 82左右 ,表明下地壳与上地幔顶部整体呈塑性的特征。根据波组及γ值横向变化特征 ,推断了该区的几条深大断裂 ,结合本地区的地震活动 ,推测地震的孕育发生不仅与构造相关 ,而且与该区的岩石性质有关 相似文献
37.
One of the potential applications of polarimetric Synthetic Aperture Radar (SAR) data is the classification of land cover, such as forest canopies, vegetation, sea ice types, and urban areas. In contrast to single or dual polarized SAR systems, full polarimetric SAR systems provide more information about the physical and geometrical properties of the imaged area. This paper proposes a new Bayes risk function which can be minimized to obtain a Likelihood Ratio (LR) for the supervised classification of polarimetric SAR data. The derived Bayes risk function is based on the complex Wishart distribution. Furthermore, a new spatial criterion is incorporated with the LR classification process to produce more homogeneous classes. The application for Arctic sea ice mapping shows that the LR and the proposed spatial criterion are able to provide promising classification results. Comparison with classification results based on the Wishart classifier, the Wishart Likelihood Ratio Test Statistic (WLRTS) proposed by Conradsen et al. (2003) and the Expectation Maximization with Probabilistic Label Relaxation (EMPLR) algorithm are presented. High overall classification accuracy of selected study areas which reaches 97.8% using the LR is obtained. Combining the derived spatial criterion with the LR can improve the overall classification accuracy to reach 99.9%. In this study, fully polarimetric C-band RADARSAT-2 data collected over Franklin Bay, Canadian Arctic, is used. 相似文献
38.
39.
加卸载响应比的新进展 总被引：2，自引：0，他引：2
本文对此作简要介绍。主要有下三方面：①预测效果好：2004年发生在中国大陆有资料地区的ML≥15级地震共17次,其中15次落入用加卸载响应比方法于2003年底预测的区域内。②通过大量基础研究(包括数值模拟,岩石力学实验及统计细观损伤力学研究),使加卸载响应比理论(LURR)建立在一个比较牢靠的科学基础上。③LURR有很大的潜力和发展空间。未来的发展空间,除预测天然地震外,还可能对矿震、水库地震、滑坡等自然灾害,甚至其它自然系统以致社会系统的灾变作出预测。 相似文献
40.