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排序方式: 共有234条查询结果,搜索用时 46 毫秒
1.
调查了潜蝇在湛江市的发生与为害情况,结果表明,美洲斑潜蝇(LiriomyzaSatiuaeBlanchard)是为害作物潜蝇的优势种,包括有6个科18种,年间发生有6个为害高峰期。应用绿潜宝、乐果、巴丹等药剂在发生为害高峰期的峰前、中、后三次用药,防治效果维持70%以上。 相似文献
2.
S. T. G. Raghukanth 《Natural Hazards》2008,46(1):1-13
In this article, analytical methods have been used to estimate ground motion during the 8 October 2005, Kashmir earthquake.
Peak ground acceleration (PGA) values at several stations in the epicentral region have been estimated by empirical analytical
source mechanism models. As an alternate analysis, PGA estimates have also been obtained using the stochastic finite fault
seismological model. The estimated PGAs are compared with that obtained from damage values. A PGA contour map in the near-source
region is provided. It is found that very near to the epicenter, PGA would have reached more than 1 g. It is demonstrated
that empirical analytical models can be effectively used to estimate ground motion due to rupture of active faults. 相似文献
3.
4.
黔西南高原区峰丛洼地的形态特征与发育规律 总被引:2,自引:0,他引:2
本文通过对黔西南坡岗地区峰丛洼地形态参数的统计和趋势面分析,论证了高原区峰丛洼地的形态特征与发育,探讨了高原区暗河纵剖面形态和喀斯特地貌演化的规律。 相似文献
5.
6.
Ali Kahriman 《Soil Dynamics and Earthquake Engineering》2004,24(11):887-892
The aim of this study is to predict peak particle velocity level at a limestone quarry located in Istanbul, Turkey. The ground vibration components were measured for 73 blast events during the bench blast optimization studies during a long period. In blasting operations; ANFO (blasting agent), gelatine dynamite (priming) and NONEL detonators (firing) were used as explosives at this site. Parameters of scaled distance (charge quantity per delay and the distance between the source and the station) were recorded carefully and the ground vibration components were measured by means of vibration monitors for every event. Then, the data pairs of scaled distance and particle velocity were analyzed. The equation of scaled distance extensively used in the literature was taken into consideration for the prediction of peak particle velocity. At the end of statistical evaluations, an empirical relationship with good correlation was established between peak particle velocity and scale distance for this site. The established relationship and the results of the study are presented. 相似文献
7.
An attenuation relationship based on Turkish strong motion data and iso-acceleration map of Turkey 总被引:2,自引:0,他引:2
This paper presents an attenuation relationship of peak ground acceleration (PGA) derived from Turkish strong motion data for rock, soil and soft soil sites and an iso-acceleration map of Turkey based on this relationship. For the purpose, among all the three-component accessible records, 221 records from 122 earthquakes that occurred in Turkey between 1976 and November 2003 were selected. The database was compiled for earthquakes with moment magnitudes (Mw) and PGA values ranging between 4.1 and 7.5, and 20 and 806 gal, and distances to epicenter considered in the database were between 5 and 100 km. From the regression analysis of the data, an attenuation equation of PGA considering rock, soil and soft soil conditions was developed. The PGA values predicted from the equation suggested in this study and those both from a few domestic equations and some imported equations were compared. In addition, an iso-acceleration map of Turkey was constructed using the suggested attenuation equation and considering both known active faults and epicenter locations of the earthquakes that have occurred in Turkey. 相似文献
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9.
This report presents a numerical investigation of the shear behavior of binary mixtures via a two-dimensional discrete element method. The effect of the coarse particle content on the peak shear strength of mixtures is investigated for different contact-type friction coefficients. A detailed analysis on the anisotropies enables us to understand the microscopic mechanisms that result in the dependency of the peak shear strengths on the coarse particle content. The contributions of different contact types to the peak shear strength are quantified. Lastly, the inter-particles structures are examined when the binary mixtures become coarse-particle-supported structures. 相似文献
10.
Fernando J. Mndez Melisa Menndez Alberto Luceo Raúl Medina Nicholas E. Graham 《Ocean Engineering》2008,35(1):131-138
This paper presents a statistical model to characterize the long-term extreme value distribution of significant wave height, conditioning to the duration of the storm and accounting for seasonality. A time-dependent version of the peak over threshold (POT) approach is used to build the model, which is then applied to specific reanalysis time series and NOAA buoy records. The model considers the annual and semiannual cycles which are parameterized in terms of harmonic functions. The inclusion of seasonal variabilities substantially reduces the residuals of the fitted model. The information obtained in this study can be useful to design maritime works, because (a) the model improves the understanding of the variability of extreme wave climate along a year and (b) the model accounts for the duration of the storm, which is a key parameter in several formulations for rubble mound breakwater design. 相似文献