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981.
图象重建是一个求逆过程具有不适定性。本文介绍的是一种从少数投影数据进行图象重建的线性代数法-Phillips-Tikhonov正则化方法,同时选择优化工具GCV确定最优的正则参数。为验证该方法,我们对日本Yohkoh卫星上塔载的硬X射线望远镜(HXT)拍摄的太阳图象进行重建。 相似文献
982.
本文在C-O-H体系流体相平衡基础上,利用现有的热力学数据和新的p-V-T资料,在pT=∑pi假定下,计算了高温、高压条件下流体相组成。结果表明,该体系主要存在五种流体相,在不同温压条件下各流体相所占比例不同。在相对较低的温、压条件下,CH4是体系中占主要的流体相(约占70%),且随温、压和氧逸度的升高,它所占比例却明显降低,所获结果为探讨无机成因天然气形成的可能性、存在的量比和稳定存在的物理化学条件提供了充分的理论依据。 相似文献
983.
岩浆侵位机制研究综述 总被引:10,自引:0,他引:10
岩浆侵位机制是研究地球动力作用的重要依据,综合国内外资料,对岩浆侵位机制提出了按侵位深度,岩浆迁移距离,岩浆结晶程度的分类方案及其联合侵位类型。分别对各类侵位机制 岩浆侵位过程,特点,研究现状进行了综述,并讨论了岩浆定位空间问题和影响岩浆定位的因素。 相似文献
984.
985.
HE Ying ZHU Xingguo Department of Geology Northwest University Xi''an Shaanxi XU PeicangXi''an Institute of Geology Chinese Academy of Geological Sciences Xi''an Shaanxi 《《地质学报》英文版》1998,72(2):191-197
Types of polymerized molecular network structure and degree of bond breakdown for glass phases of magmatic inclusions and glassy matrix in volcanic rocks from the Shengli oilfield have been defined by the laser Raman spectroscopic investigation. There are significant differences in types of polymerized molecular network structure and degree of bond 'breakdown of the magmatic glass phases between the non-CO2 and COa gas pools: magmatic glass phases of fluid inclusions and matrix in volcanic rocks from the CO2 gas pool contain more sheet network molecules and have a greater degree of bond beakdown than those from the non-CO2 gas pool; and when gas bubbles occur in evolving magma, magma saturated with volatile components has more sheet network molecules. The results suggest the magma-degassing mechanism of the formation of CO2 gas pools in the Shengli oilfield. 相似文献
986.
塔里木盆地塔中地区奥陶系碳酸盐岩储层空隙研究 总被引:11,自引:0,他引:11
空隙是构成碳酸盐岩储层的基本单元,空隙发育史对应了成岩演化史,且不同类型空隙的储层具有不同的分布规律。塔里木盆地塔中地区奥陶系碳酸盐岩储层的空隙可以分为6类21种,以裂缝—孔洞型为主,礁、丘、滩相碳酸盐岩、中—细晶白云岩与古岩溶和构造岩溶的复合区为有利空隙发育带,也是风化壳型油气藏和内幕型油气藏的有利储集相带。 相似文献
987.
位移时空综合分析法及其在边坡工程中的应用 总被引:1,自引:1,他引:0
以往对监测位移数据分析方法主要是位移-时间关系分析。但监测数据包含了大量对工程设计和施工都很有用的信息,其中不乏位移-空间方面的信息;另一方面,从工程设计和施工角度看,除需要位移-时间信息外,还需要位移-空间信息。位移时空综合分析法的提出旨在综合位移-时间和位移-空间等两方面的信息,为工程设计和施工服务。该方法依表现形式不同又分为竖线法和曲面法两种。本文将通过五强溪船闸边坡工程实例,来进一步说明位移时空综合分析法的原理及其应用。 相似文献
988.
Evaporation of perennial semi‐arid woodland in southeastern Australia is adapted for irregular but common dry periods
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Measurements of water vapour flux from semi‐arid perennial woodland (mallee) were made for 3 years using eddy covariance instrumentation. There have been no previous long‐term, detailed measures of water use in this ecosystem. Latent energy flux (LE) on a half hourly basis was the measure of the combined soil and plant evaporation, ‘evapotranspiration’ (ELE) of the site. Aggregation over 3 years of the site measured rain (1136 mm) and the estimated evaporation (794 mm) suggests that 342 mm or 30% of rain had moved into or past the root zone of the vegetation. Above average rainfall during 2011 and the first quarter of 2012 (633 mm, 15 months) would likely have been the period during which significant groundwater recharge occurred. At times immediately after rainfall, ELE rates were the same or exceeded estimates of potential E calculated from a suitably parameterized Penman–Monteith (EPMo) equation. Apparent free water E from plant interception and soil evaporation was about 2.3 mm and lasted for 1.3 days following rainfall in summer, while in autumn, E was 5.1 mm that lasted over 5.4 days. The leaf area index (LAI) needed to adjust a wind function calibrated Penman equation (EPMe) to match the ELE values could be back calculated to generate seasonal change in LAI from 0.12 to 0.46 and compared well with normalized difference vegetation index; r = 0.38 and p = 0.0213* and LAI calculated from digital cover photography. The apparently conservative response of perennial vegetation evaporation to available water in these semi‐arid environments reinforces the conclusion that these ecosystems use this mechanism to survive the reasonably common dry periods. Plant response to soil water availability is primarily through gradual changes in leaf area. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
989.
The paper presents an analysis of 17 long annual maximum series (AMS) of flood flows for Swiss Alpine basins, aimed at checking the presence of changes in the frequency regime of annual maxima. We apply Pettitt's change point test, the nonparametric sign test and Sen's test on trends. We also apply a parametric goodness‐of‐fit test for assessing the suitability of distributions estimated on the basis of annual maxima collected up to a certain year for describing the frequency regime of later observations. For a number of series the tests yield consistent indications for significant changes in the frequency regime of annual maxima and increasing trends in the intensity of annual maximum discharges. In most cases, these changes cannot be explained by anthropogenic causes only (e.g. streamflow regulation, construction of dams). Instead, we observe a statistically significant relationship between the year of change and the elevation of the catchment outlet. This evidence is consistent with the findings of recent studies that explain increasing discharges in alpine catchments with an increase in the temperature controlling the portion of mountain catchments above the freezing point. Finally, we analyse the differences in return periods (RPs) estimated for a given flood flow on the basis of recent and past observations. For a large number of the study AMS, we observe that, on average, the 100‐year flood for past observations corresponds to a RP of approximately 10 to 30 years on the basis of more recent observation. From a complementary perspective, we also notice that estimated RP‐year flood (i.e. flood quantile (FQ) associated with RP) increases on average by approximately 20% for the study area, irrespectively of the RP. Practical implications of the observed changes are illustrated and discussed in the paper. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
990.
Impact of climate change on 24‐h design rainfall depth estimation in Qiantang River Basin,East China
The frequency and magnitude of extreme meteorological or hydrological events such as floods and droughts in China have been influenced by global climate change. The water problem due to increasing frequency and magnitude of extreme events in the humid areas has gained great attention in recent years. However, the main challenge in the evaluation of climate change impact on extreme events is that large uncertainty could exist. Therefore, this paper first aims to model possible impacts of climate change on regional extreme precipitation (indicated by 24‐h design rainfall depth) at seven rainfall gauge stations in the Qiantang River Basin, East China. The Long Ashton Research Station‐Weather Generator is adopted to downscale the global projections obtained from general circulation models (GCMs) to regional climate data at site scale. The weather generator is also checked for its performance through three approaches, namely Kolmogorov–Smirnov test, comparison of L‐moment statistics and 24‐h design rainfall depths. Future 24‐h design rainfall depths at seven stations are estimated using Pearson Type III distribution and L‐moment approach. Second, uncertainty caused by three GCMs under various greenhouse gas emission scenarios for the future periods 2020s (2011–2030), 2055s (2046–2065) and 2090s (2080–2099) is investigated. The final results show that 24‐h design rainfall depth increases in most stations under the three GCMs and emission scenarios. However, there are large uncertainties involved in the estimations of 24‐h design rainfall depths at seven stations because of GCM, emission scenario and other uncertainty sources. At Hangzhou Station, a relative change of ?16% to 113% can be observed in 100y design rainfall depths. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献