Alternative Fuzzy Cluster segmentation of remote sensing images based on Adaptive Genetic Algorithm

Remote sensing image segmentation is the basis of image understanding and analysis. However, the precision and the speed of segmentation can not meet the need of image analysis, due to strong uncertainty and rich texture details of remote sensing images. We proposed a new segmentation method based on Adaptive Genetic Algorithm (AGA) and Alternative Fuzzy C-Means (AFCM). Segmentation thresholds were identified by AGA. Then the image was segmented by AFCM. The results indicate that the precision and the speed of segmentation have been greatly increased, and the accuracy of threshold selection is much higher compared with traditional Otsu and Fuzzy C-Means (FCM) segmentation methods. The segmentation results also show that multi-thresholds segmentation has been achieved by combining AGA with AFCM.     

内陆水体好氧甲烷氧化过程研究进展

内陆水体是全球碳循环的关键组成部分,是大气中甲烷(CH4)的重要来源,每年从内陆淡水与自然湿地排放进入大气的CH4约为185～357 Tg/a.通常,内陆水体中CH4主要由分布于水层底部的厌氧区或沉积层内的产甲烷菌介导产生,其向水层表面传输的过程中易被甲烷氧化菌所氧化.甲烷氧化菌可分为好氧甲烷氧化菌和厌氧甲烷氧化菌,有...     

基于MODIS数据的雪面温度遥感反演

On the basis of simplification of the Planck function in a low temperature range, this paper revises the practical split-window algorithm and presents a method for retrieving snow surface temperature （Ts） based on MODIS data in the middle-latitude region. The application of this method in Qinghai Lake region reveals that it is feasible for the retrieval of Ts. Results of correlation analysis indicate that there was strong negative relationship between Ts and altitude. By analyzing three typical areas in which land cover was relatively homogenous, this paper discusses the relationship between Ts and normalized difference snow index （NDSI） and then presents a new concept named ＂NDSI-Ts space＂.     

多层垂直对称轴横向各向同性介质精确走时计算

给出了计算多层垂直对称轴横向各向同性（VTI）介质精确射线路径和走时的方法,所用的体波相速度公式、群速度公式和Snell定律都是严格的显式解析公式. 任意基本波的射线路径和走时计算问题都可以转化成一个等效的透射问题,再用文中的公式来计算,具体实现方法用一个多次波和一个首波的实例给出. 最后分别用精确公式和Thomsen近似公式计算了相同模型相同基本波的走时曲线. 比较两者计算结果可发现, 近似公式反复使用会使误差积累,同时揭示了近似公式适用范围的局限性,强调了使用近似公式需要注意其适用范围的重要性.      

裂隙-管道介质泉流域水文地质模拟试验

为了深入认识岩溶泉流域的流量过程影响因素和作用机制,以西南岩溶泉流域水文地质概念模型为原型,建立了实验室尺度下的裂隙-管道介质物理模型和数值模型。选取补给雨强、泉口直径、落水洞与开采井的位置作为影响因子,模拟了泉流量过程。试验结果表明:单次降水试验可以观测得到泉流量增加、平稳波动和衰减共三个阶段;同一泉口直径条件下,补给强度对泉流量衰减系数的影响极小,直径为3,4,5,7 mm的泉口直径对应的衰减系数分别为0.003 6,0.006 7,0.011 5,0.012 9,泉口直径与衰减系数呈近似对数关系;落水洞汇流水量占泉流量的比例远大于裂隙;2~3 mm是微小裂隙与较大裂隙的过渡区域,两种类型的介质泉流量过程差异明显;开采井分别位于泉口附近、模型中间位置和落水洞时,泉流量衰减系数依次减小。     

骨架矿物—粘土矿物碱耗协同效应研究

选择了克拉玛依油田二中区Ｔ２ｋ１砂砾岩储层中的六种储层矿物,石英,正长石,微斜长石,Ｃａ－蒙脱石,高岭石,伊利石。在不同的条件下研究了这六种矿物的碱耗量,还研究骨架矿物与粘土矿物按照一定的质量配比而成的复配矿物的碱耗量,探讨了矿物碱耗的协同效应,结果表明单矿物的碱耗序列为,蒙脱石（Ｓ）〉高岭石（Ｋ）〉伊利石（Ｉ）〉微斜长石（Ｍ）〉石英（Ｑ）〉正长石（Ｊ）,复配物的碱耗总体上受粘土矿物控制,尤其是蒙     

湘西洛塔表层岩溶泉的生态环境类型及水文特征

岩溶石山区表层岩溶带的调蓄功能可有效控制石漠化的加剧并为严重缺水地区提供饮用水。文章以湖南洛塔为例,在大量的野外调查基础上,通过对洛塔岩溶区表层岩溶系统生态环境与表层岩溶泉水文特征的对比研究,按生态环境属性将表层岩溶泉分为三种主要类型:森林环境表层岩溶泉、石漠化环境表层岩溶泉及石漠化-森林过渡环境表层岩溶泉。详细论述上述三种表层岩溶泉的发育条件与水文特征:森林环境表层岩溶泉具有持续稳定的水文动态与流量;石漠化环境表层岩溶泉流量与降雨量相对应,动态极不稳定;石漠化与森林过渡环境表层岩溶泉流量排泄峰值具有随泉域植被覆盖率增加而缓和的趋势。按照环境类型对表层岩溶泉进行分类,可直观地显示其特殊的水文特征,有助于岩溶泉的合理开发和综合利用。     

原子荧光法测定地质样品和生物样品中痕量锗

本义采用氢化物法分离技术，使样品溶液中的锗转变为气态氢化锗（ＧｅＨ＿４），达到与基体分离的目的，有效地消除了各种离子的干扰。研究并证明了在１５％以上的磷酸介质中，各种酸（ＨＣｌ，Ｈ＿２ＳＯ＿４，ＨＮＯ＿３，ＨＣＩＯ＿４）度在１％－１０％的范围内变化均不影响锗的测定，大大简化了操作手续，方法灵敏度高、使用范围广、准确、简便、快速。Ｇｅ的检出限为０．１μｇ／ｇ，相对标准偏差＜７％。可应用于地质，冶金，生物，环保，卫生，食品中微量锗的测定。     

新生代构造运动对黄土高原地貌分异与黄河形成的控制作用

黄土高原面积广大,不同区域的新生代构造演化有很大差别,根据新生代构造运动特征与沉积过程的差异,将黄土高原划分为鄂尔多斯稳定地块、陇西地区和汾渭新生代裂谷3个新生代构造运动分区.新生代构造运动控制黄土高原新生代沉积与侵蚀过程,从而产生明显地貌分异,并可划为3个一级地貌分区:1)鄂尔多斯黄土地貌区.第四纪黄土覆盖在新近纪红土梁、峁及红土盆地等古地形之上,后被侵蚀,形成复杂多变的黄土地貌景观;2)陇西黄土地貌区.主体为新近纪红土地貌,上覆少许第四纪黄土,实际为红土地貌区;3)汾渭裂谷黄土地貌区.裂谷盆地的地貌主体为河流两侧的阶地和台地,其上堆积第四纪黄土,形成不同时期的黄土台塬.鄂尔多斯周边新生代裂谷的出现控制了黄河的发育.新近纪末银呼裂谷与汾渭裂谷进入快速发展期,吕梁山相应隆起;鄂尔多斯地块西北部也轻微抬升,使古黄河初步形成并流经晋陕峡谷一带,进入三门湖并东流入海.第四纪时期早期,黄河曾长期处于河湖并存期,中更新世末,黄河溯源侵蚀使湖泊消失,并呈现目前的黄河地貌景观.     

Erratum to: Iron isotope variations in spinel peridotite xenoliths from North China Craton: implications for mantle metasomatism

Iron isotopes, together with mineral elemental compositions of spinel peridotite xenoliths and clinopyroxenites from Hannuoba and Hebi Cenozoic alkaline basalts, were analyzed to investigate iron isotopic features of the lithospheric mantle beneath the North China Craton. The results show that the Hannuoba spinel peridotite xenoliths have small but distinguishable Fe isotopic variations. Overall variations in δ⁵⁷Fe are in a range of −0.25 to 0.14‰ for olivine, −0.17 to 0.17‰ for orthopyroxene, −0.21 to 0.27‰ for clinopyroxene, and −0.16 to 0.26‰ for spinel, respectively. Clinopyroxene has the heaviest iron isotopic ratio and olivine the lightest within individual sample. No clear linear relationships between the mineral pairs on “δ-δ” plot suggest that iron isotopes of mineral separates analyzed have been affected largely by some open system processes. The broadly negative correlations between mineral iron isotopes and metasomatic indexes such as spinel Cr#, (La/Yb)_N ratios of clinopyroxenes suggest that iron isotopic variations in different minerals and peridotites were probably produced by mantle metasomatism. The Hebi phlogopite-bearing lherzolite, which is significantly modified by metasomatic events, appears to be much heavier isotopically than clinopyroxene-poor lherzolite. This study further confirms previous conclusions that the lithospheric mantle has distinguishable and heterogeneous iron isotopic variations at the xenoliths scale. Mantle metasomatism is the most likely cause for the iron isotope variations in mantle peridotites.