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221.
This paper presents an assessment ofgeomagnetic hazard on the five largest power systemsin Canada. From east to west these are: Nova ScotiaPower, Hydro-Quebec, Ontario Hydro West System, Manitoba Hydro, and the northern B.C. Hydro system. The aim of this study was to determine howfrequently, and where in a system, largegeomagnetically induced currents (GIC) could beexpected. To do this, an analysis was made of thespectral characteristics of the magnetic fieldvariations that cause GIC, and a review was made ofpublished magnetotelluric soundings in order todetermine conductivity models for different parts ofthe country. The magnetic field spectra and theconductivity information were then used to determinethe electric fields produced during geomagneticdisturbances. A relation was determined betweenelectric field magnitudes and the magnetic activityindex, Kp so that statistics for Kp could be used todetermine the occurrence rates of large electricfields. Power system models were used to determinethe GIC produced by the `1-year' and `10-year'electric fields experienced by each power system. 相似文献
222.
In this paper we study the rooted tree model applying the concepts of probability to obtain results of importance in understanding power-law distributions in pure populations and also in an ensemble of pure populations. The well-known Gutenberg-Richter relation, which is an empirical relation providing the number of earthquakes whose magnitude exceeds a given value, is shown to be an asymptotic form of survivor function of earthquake magnitudes. The implications of this model are briefly discussed in relation to other branches of sciences where power-law distributions are encountered. 相似文献
223.
J. E. Glynn P. W. Glynn 《Stochastic Environmental Research and Risk Assessment (SERRA)》1996,10(1):17-37
A diffusion approximation for a network of continuous time reservoirs with power law release rules is examined. Under a mild assumption on the inflow processes, we show that for physically reasonable values of the power law constants, the system of processes converges to a multi-dimensional Gaussian diffusion process. We also illustrate how the limiting Gaussian process may be used to compute approximations to the original system of reservoirs. In addition, we study the quality of our approximations by comparing them to results obtained by simulations of the original watershed model. The simulations offer support for the use of the approximation developed here. 相似文献
224.
陆相地层的层序地层学研究近年来取得了较大的进展,尤其在层序的组成、层序界线和最大洪泛面的识别以及层序模式的建立等方面研究得比较深入。层序地层的组成包括层序组合和层序的内部单元。层序界线和最大洪泛面的识别是陆相地层层序地层学研究的关键。目前已初步建立了箕状断陷盆地、坳陷盆地以及冲积地层背景的层序模式。 相似文献
225.
专题制图中,所收集到的数据经常是单因素的,而在专题地图上却往往需要把多个单因素专题数据进行综合分类来表示。本文中,采用Fuzzy-Grey局势决策(下简称F-G决策)来研究多因素专题数据的综合分类问题,把“数据的模糊性”引入到灰色局势决策之中,根据不同情况,讨论各局势上效果测度中模糊隶属度确定的建模方法,在合适的隶属函数的基础上,在计算机上对实例分类进行程序运行,获得满意的结果。研究表明应用该方法在专题制图中对多因素数据进行综合分类是一种有效的手段。 相似文献
226.
聚煤盆地富煤规律是煤地质学研究之焦点。富煤规律研究的突出进展主要包括聚煤模式、富煤带和富煤单元以及现代泥炭比较沉积学研究。尤其是近年来富煤单元和现代泥炭比较沉积学研究更清楚地揭示煤赋存规律与成因煤相和工艺煤相之间的内在联系,从而为聚煤盆地优质煤的预测提供有效的方法。 相似文献
227.
Power spectral characteristics of the seismic activities before and after the seven large earthquake — Haicheng, Tangshan,
Lancang, Longling, Mabian, Puer and Songpan are studied by spectrum analysis method. The results show that they all have continuous
power spectrum and aperiodic behaviour. When the time away from the large earthquake occurrence, the characteristics of the
seismic activities are obviously accompanied by stochastic components. About one year before main shock, the moving orbits
constructed by spectrum amplitudes showed the contracting tendency. And the properties during that time may display as flicker
noise. One’s another time almost mixed whole phase space. But the essence of seismic activities after main shocks is a chaotic
state accompanied with much noises.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 276–281, 1993.
This subject is supported by the Chinese Joint Seismological Foundation. 相似文献
228.
本文在综合地质、地貌、地形变、地震、物探和年代测定等资料的基础上,对东岗断裂的活动性进行了全面分析。所得结果表明,东岗断裂性在中更新世时期有过两期活动,但自晚更新世(10万年)以来没有活动,故可鉴定为非能动性断裂。 相似文献
229.
ABSTRACTPower plants often use river waters for cooling purposes and can be sensitive to droughts and low flows. Water quality is also a concern, due to algal blooms and sediment loads that might clog filters. We assessed the impacts of droughts on river flow and water quality from the point of view of power plant operation. The INCA (INtegrated CAtchment) water quality model was coupled with a climate model to create a dataset of flow and water quality time series, using the River Trent (UK) as a case study. The result hints to a significant decrease in flows and an increase in phosphorus concentrations, potentially enhancing algal production. Power plants should expect more stress in the future based on the results of this study, due to reduced cooling water availability and decreasing upstream water quality. This issue might have serious consequences also on the whole national power network. 相似文献
230.
The possible influences of the increasing anthropogenic emissions in India on tropospheric ozone and OH 总被引:2,自引:0,他引:2
A 3-D chemical transport model (OSLO CTM2) is used to investigate the influences of the increasing anthropogenic emission in India. The model is capable of reproducing the observational results of the INDOEX experiment and the measurements in summer over India well. The model results show that when NOx and CO emissions in India are doubled, ozone concentration increases, and global average OH decreases a little. Under the effects of the Indian summer monsoon, NOx and CO in India are efficiently transported into the middle and upper troposphere by the upward current and the convective activities so that the NOx, CO, and ozone in the middle and upper troposphere significantly increase with the increasing NOx and CO emissions. These increases extensively influence a part of Asia, Africa, and Europe, and persist from June to September. 相似文献