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421.
大型影像数据库中的色调调整方法 总被引:5,自引:1,他引:5
在详细分析造成大型影像库中色调差异成因的基础上,通过比较几种影像数字镶嵌时常采用的色调过渡匹配平衡方法,提出了一种充分考虑影像本身特征的相邻相关影像色调调整平滑过渡方法。同时为了减少大幅面影像调整时调整误差的空间传递性,给出了基于四叉树的多次调整法。 相似文献
422.
水库诱发地震研究的历史、现状与发展趋势 总被引:13,自引:0,他引:13
简要回顾了水库诱发地震(RIS)研究的历史。从诱震库区的地质构造条件、水库蓄水诱震机理的数学物理模型、水库诱发地震的地震学、水库诱发地层危险性评价的理论和方法四个方面,介绍了水库诱发地震研究过程中各阶段所取得的重要认识。指出了目前水库诱发地震研究中存在的主要问题。提出以岩体结构控制论为理论基础,重视库区岩体结构、水文地质结构研究以取得诱震环境模型的发展与创新,以非均质各向异性介质环境流固耦合数值模拟为手段,以取得诱震机理认识的深化,是未来水库诱发地层研究的发展趋势。 相似文献
423.
YIWanxia ZHAOZongju LIXuetian SHENJinlong ZHOUJingao 《大地构造与成矿学(英文版)》2003,27(1):130-144
Comprehensive analyses were made based on seismic prospecting data, electrical prospecting data and basin simulation data as well as regional geological data and thorough discussions were conducted about the complicated structures, features and evolution of Hefei Basin in Early Cretaceous in this study, and it was derived that that Hefei Basin was a composite basin formed during the transformation of the stress field from compressive toward tensile in Early Cretaceous. In other words, this basin was a foreland basin of gliding-thrust type, which is mainly controlled by the Dabie orogenic belt in the south side in the early to middle period of Early Cretaceous, while being a strike-slip basin of pull-apart type, which is mainly controlled by the activity of Tanlu fracture in the east side in the middle to late period of Early Cretaceous. Moreover, the potential Lower Cretaceous oil and gas system in the pull-apart basin and the vista for its prospecting were explored in this study. Tectonism of the Tanlu fracture was further discussed based on the results of characterization of the basin, and it was pointed out that this is beneficial and instructive to the oil and gas prospecting in Hefei Basin. 相似文献
424.
425.
详细描述了北羌塘乌兰乌拉湖地区白垩纪地层剖面,将区内白垩系划分为错居日组和桑恰山组。沉积相分析表明,乌兰乌拉湖地区错居日组主要为冲积扇至河流相沉积,岩性及厚度变化较大,而桑恰山组为湖泊、湖三角洲至河流相沉积。初步认为错居日组为早日垩世地层,桑恰山组为早白垩世晚期至晚白垩世地层。 相似文献
426.
427.
By using the wavelet transform method,the ENSO(2—7 a)signal and the decadal variability(8—20 a)are filtered out from the long-term SST data sets in order to investigate characteristicsof the decadal variability and its impact on the ENSO.It is found that there are two different kindsof decadal SSTA modes-horseshoe and horse saddle patterns in the tropical Pacific.Thehorseshoe pattern represents that the decadal SSTA variability in the central Pacific is in phasewith that in the eastern Pacific.The horse saddle pattern is named that they are out of phase.Theformer constituted the decadal variability before 1990s and the latter mainly prevailed during1990s.As the response of atmosphere to the ocean,two decadal wind patterns appear inassociation with the SST decadal modes.One is characterized by anomalous development of thezonal wind,the other by anomalous development of the meridional wind.These two kinds ofmodes can also be regarded as different phases of the decadal oscillation.Further studies haveshown that the influences of the two kinds of modes on the ENSO are different.The horse saddlemode has a stronger impact on the ENSO than the horseshoe mode.A possible mechanism for the influence of the decadal variability on the ENSO signal ispresented.The central part of the thermocline along the equatorial Pacific moves up or downsimultaneously with its eastern part while the decadal variability bears the horseshoe pattern.Butthe two segments of the thermocline in the central and eastern Pacific act oppositely while thedecadal variability shows the horse saddle pattern.In this case it has an-influence on the individualENSO'events by the superposition of the decadal variability. 相似文献
428.
利用日本境内的高空间分辨率的双频GPS台站资料,观测研究了发生于2000年7月中旬太阳强活动期间的一次大尺度电离层行扰. 结果表明:在7月15日11:00UT-1:00UT期间观测区域的电离层中出现了大尺度电离层行扰. 在15:00UT之前,扰动周期为2h左右,在15:00UT以后,扰动周期为1h左右;总电子含量扰动幅度的变化范围约为1-2TECU;通过对15:00-17:00UT之间总电子含量扰动曲线同相位点的分析,发现这期间的电离层行扰的扰动速度约为600-700m/s,扰动波长在2200km左右,扰动传播的方向几乎沿着经线从高纬向低纬传播. 该行扰与此次强太阳活动有直接的关系,因其发生在7月15日的磁暴急始之前数小时,因此与磁暴本身没有因果关系,应与磁暴之前先期到达地球空间的高能质子流有关. 相似文献
429.
提出一种可能产生行星际磁场南北分量扰动的物理机制,并将此物理机制运用于三维运动学模型,对原模型作了改进. 使用改进后的模型模拟研究了1997年5月12日06:30UT爆发的晕状(halo)日冕物质抛射(CME)事件对行星际磁场和等离子体的扰动,以及1978-1981年间17个与CME有关的行星际扰动事件. 在17个事件中有14个事件可准确预测出行星际磁场南北分量的方向,准确率为82%. 结果表明,模型计算出的行星际磁场南北分量的扰动方向与观测的方向是基本一致的. 相似文献
430.
By using the wavelet transform method,the ENSO (2-7 a) signal and the decadal variability (8-20 a) are filtered out from the long-term SST data sets in order to investigate characteristics of the decadal variability and its impact on the ENSO.It is found that there are two different kinds of decadal SSTA modes-horseshoe and horse saddle patterns in the tropical Pacific.The horseshoe pattern represents that the decadal SSTA variability in the central Pacific is in phase with that in the eastern Pacific.The horse saddle pattern is named that they are out of phase.The former constituted the decadal variability before 1990s and the latter mainly prevailed during 1990s.As the response of atmosphere to the ocean,two decadal wind patterns appear in association with the SST decadal modes.One is characterized by anomalous development of the zonal wind,the other by anomalous development of the meridional wind.These two kinds of modes can also be regarded as different phases of the decadal oscillation.Further studies have shown that the influences of the two kinds of modes on the ENSO are different.The horse saddle mode has a stronger impact on the ENSO than the horseshoe mode.A possible mechanism for the influence of the decadal variability on the ENSO signal is presented.The central part of the thermocline along the equatorial Pacific moves up or down simultaneously with its eastern part while the decadal variability bears the horseshoe pattern.But the two segments of the thermocline in the central and eastern Pacific act oppositely while the decadal variability shows the horse saddle pattern.In this case it has an-influence on the individual ENSO'events by the superposition of the decadal variability. 相似文献