有关边界层问题中一类奇异积分方程新的存在性结果     

石丽莉  张高勋 《成都信息工程学院学报》2006,21(6):891-896

对边界层理论新结果中出现的一类奇异积分方程w（t）=∫1 t（1-s）（λ＋λs＋s）/w（s）ds＋（1-t）∫t 0s/w（s）ds,t∈（0,1）进行讨论，并得出了上述方程在λ∈（-1/2,0）上正解存在性的新结果。  相似文献   

BACKGROUND STUDY ON NON-RESIDUAL PHASE OF ELEMENTS IN CHANGJIANG AND HUANGHE ESTUARINE SEDIMENTS     

刘新威  吴景阳  蔡月琴  林荣根  韩桂荣 《中国海洋湖沼学报》1996,14(3):282-290

Analysis of Zn, Cu, Pb, Co, Cr, Li, Ni, K, Al, Fe extracted by 1 mol/L HCl or 0.5 mol/LHCl/H_2O_2, showed concentrations of Zn, Cu, Pb, Co, Cr, Fe, Ni were significantly correlated with Li, Al,K, and clay. Two methods are used to indicate the background value of the non-residual phase of elementsin sediments, and are the same as the methods used to indicate the background value of totalconcentrations in sediments. The first method uses correlograms and regression equations,the second usesthe mean element concentrations normalized with grain size. Li, Al, K can be used as reference elements to determine the background value of Zn, Cu, Pb, Co,Cr, Ni, Fe, while the clay concentration's correlation with some extractable concentrations can be used tocalculate the background value of the non-residual phase of elements as a percentage of clay concentrationin the sediments. Based on this study, the concept of using the background value of the non-residualphase of elements to compare the pollution level in differ  相似文献   

抗差估计的初值选择     

王振杰  欧吉坤  曲国庆 《大地测量与地球动力学》2001,21(3):32-35

对L1 范估计的平差值和LS估计的平差值作为抗差估计的初值进行了比较 ,指出在 ρ函数是严凸函数时 ,二者无明显的区别。因为LS估计简单且易于计算 ,因此建议用LS估计的平差值作为抗差估计的初值。  相似文献   

广西河池地区矿产资源勘查成果展销会情况介绍     

项开文 《南方国土资源》1996,(3)

１９９５年７月１１日—１２日，广西地矿厅和河池地区行署首次联合举办矿产资源勘查成果展销会，会址设在河池市，与会代表１３０余人。展销会提交大会展销的矿产资源勘查成果３８项，引资勘查项目３８项。经买卖双方三天的洽谈，涉及到的项目２５项，会议期间签订矿产资源勘查成果合同协议４项，愈千万元，取得较好的社会经济效益。为地勘资金多渠道来源开辟了新路子，对促进地勘单位地质找矿工作及勘查成果有偿使用发挥了重要作用  相似文献   

广西芒场锡多金属矿田稳定同位素组成对矿床成因探讨     

邹锡青  王思源 《南方国土资源》1993,(2)

笔者曾对广西芒场锡多金属矿田的稳定同位素进行研究。本文根据硫、铅、氢、氧、碳等稳定同位素组成和锶的初始值提供的信息.探讨了矿床成因。并结合矿田矿床地质特征、控矿条件及有关统计参数,参考前人对矿床认识的基础上,修正提出了该矿田混合热液成矿模式,可供类似矿床研究和找矿的参考。  相似文献   

用遗传算法解算病态方程   总被引：7，自引：1，他引：6  

曾群意  欧吉坤 《大地测量与地球动力学》2003,23(3):93-97

对应用遗传算法解决病态方程问题进行了探讨。利用拟合法而不是通过法方程求解参数，从而避免了法方程系数求逆，使病态方程的解答有了较好的结果。通过模拟计算并和其他方法进行比较，证明该方法是可行的和有效的。  相似文献   

Beyond the numbers: Understanding the value of vegetation to rural livelihoods in Africa     

Thembela Kepe 《Geoforum》2008,39(2):958-968

Different types of vegetation found in local environments are of value to rural livelihoods of many African households. However, the dominant way of expressing this value, which is mainly through economic valuation studies, is potentially limiting this knowledge’s usefulness in policy and research, due to the inability to present full picture. Using literature review and insights from field work, the paper argues that realized and notional values of vegetation to rural livelihoods are socially constructed and contested, and - in addition to understanding local livelihood context, which include social difference, and ecological dynamics - a focus on social institutions as terrains of negotiation is crucial. This means that resource value in rural livelihoods can be realized through contested and negotiated access arrangements that are mediated by complex institutions at local and external levels.  相似文献   

攀西地区铂族元素地球化学异常分布及其筛选   总被引：1，自引：0，他引：1  

任光明  李佑国  陈旭  骆耀南  费光春  包凤琴  陈杰 《地质与勘探》2008,44(1):62-66

攀西地区不同时代地层的水系沉积物中铂族元素地球化学背景值具有明显的规律性分布.笔者通过对该地区铂族元素含量在各地层中的分布以及地球化学异常的圈定、归并和分类,结合有关铂族矿床地球化学特征的认识,通过对水系沉积物中Pt、Pd综合异常的筛选,在铂族元素综合衬值异常图的基础上共划分出Ⅰ类异常4个、Ⅱ类异常19个、Ⅲ类异常23个以及Ⅳ类异常14个.初步筛选出的19个Ⅱ类异常子区可为进一步开展铂族矿床找矿工作提供依据.  相似文献   

Memorial landscapes: analytic questions and metaphors   总被引：1，自引：0，他引：1  

Owen J. Dwyer  Derek H. Alderman 《GeoJournal》2008,73(3):165-178

Over the past two decades, geographers have probed the intersection of collective memory and urban space. Their sustained interest in the subject reflects an understanding of the social condition of commemoration and the important role that space plays in the process and politics of collective memory. Along with other critical social scientists, geographers envision these public symbols as part of larger cultural landscapes that reflect and legitimate the normative social order. A review of the extant literature indicates that geographers scrutinize memorial landscapes through three conceptual lenses that may be understood via the metaphors of ‘text,’ ‘arena,’ and ‘performance.’ These metaphors are in turn mobilized through a series of analytic questions that serve to identify the interests served and denied by landscape ‘texts,’ the ‘arenas’ in which they are produced, and the ways in which they are enacted via ‘performance.’ This article’s synopsis of the subfield’s predominant metaphors and its attendant questions contributes to the ongoing cultural geographic project of articulating and implementing methods for interpreting landscapes as open-ended symbolic systems.

Derek H. AldermanEmail:

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喜马拉雅山脉的地质地貌特征:来自SRTM数字高程模型和降水量数据的约束   总被引：3，自引：1，他引：2       下载免费PDF全文

王猛  刘焰  何延波  魏东 《地质科学》2008,43(3):603-622

利用GTOPO30和SRTM3数字高程(DEM)数据,提取了喜马拉雅山脉(造山带)的数字高程模型并对其进行了地质地貌的初步分析。从SRTM3数字高程数据提取出坡度数据,初步分析了喜马拉雅山脉坡度和高程的特征。数字高程和坡度图清楚地展现了喜马拉雅大型断裂带(构造边界)的空间分布特征。分析了中国气象局下属的西藏、青海、四川和云南4省区气象观测台站55年来的年平均降水量观测数据、喜马拉雅山脉南坡的年平均降水量数据、喜马拉雅DEM和裂变径迹数据,发现喜马拉雅山脉从东至西,年平均降水量逐渐减少,地形起伏逐渐变小,而高程渐次升高,与此同时剥蚀速率降低;从北至南,年平均降水量逐渐增加,地形起伏增大,高程快速降低,而剥蚀速率则急剧升高。这充分说明了喜马拉雅年平均降水量大的地区,地表剥蚀作用相对较强,年平均降水量小的地区,地表剥蚀作用则较弱,即:在喜马拉雅地区,长周期的地表剥蚀过程(可长达数个百万年时间尺度)和短周期(仅仅50年)的降水量观测是耦合的。  相似文献