补偿电流对核旋分量仪的影响及补偿稳流装置     

于明鑫  李铁 《地震地磁观测与研究》1993,14(1):51-54

着重讨论补偿电流对核旋分量磁力仪在观测地磁场垂直分量中的影响,介绍了补偿稳流装置和在大连地磁台应用的效果。  相似文献   

黑龙江省气候旱涝定量诊断分析     

陈莉  李铁  刘玉莲  王保民 《黑龙江气象》1999,(2):1-6

简单介绍了气候旱涝分析方法,并选择“ＢＭ”方法作为本省气候旱涝定量分析方法。以哈尔滨气候区为例,利用“ＢＭ”方法建立了气候旱涝数学模型,在此基础上提出气候旱涝定量化指标,并进行了动态追踪定量化诊断分析  相似文献   

IKONOS影像的定向精度研究     

王铁军刘倩  李海生 《东北测绘》2007,30(6):73-75,81

简要介绍了IKONOS卫星遥感影像适用于生产地理信息产品的特点，通过生产试验研究详细分析了IKONOS影像作为数据源在生产地理信息产品时的定向精度问题。  相似文献   

一种基于GTP的地下真3D集成表达的实体模型   总被引：5，自引：0，他引：5  

吴立新  陈学习  车德福  徐磊 《武汉大学学报(信息科学版)》2007,32(4):331-335

从建模对象、组成元素和拓扑描述三个方面对广义三棱柱（GTP）模型进行了修正和扩展。基于修正与扩展后的GTP模型，从地学、几何、拓扑三个层面对地下实体进行了提炼，抽象出8种空间构模几何元素，并将地下实体划分为点、线、面和体4类，体实体又进一步划分为简单体、复合体和复杂体，进而提出了一种基于GTP的地下真3D集成表这的实体模型（GTP—based entity model，GTP—EM）；采用面向对象的方法，通过构模元素之间拓扑关系的定义实现了地下实体的拓扑描述，并应用实例验证了GTP—EM的可行性。  相似文献   

干旱半干旱区土壤含水量反演与验证   总被引：8，自引：2，他引：6       下载免费PDF全文

李琴  陈曦  包安明  刘铁  王金林 《水科学进展》2010,21(2):201-207

基于MODIS遥感影像和表观热惯量法,以新疆为研究区,建立了适用于干旱半干旱区1 m土体的土壤含水量反演模型。模型根据高表观热惯量,高土壤含水量,低表观热惯量,低土壤含水量这一理论,通过日地表温差和宽波段反照率确定土壤含水量的时空变化。假设通过1 m土体的土壤水通量正比于上下底层土壤含水量的差值,利用水平衡方程建立土壤表面和底层土壤含水量关系方程,并利用中国土壤类型特点确定优化模型。通过验证结果表明,壤土和壤质粘土这两类土壤含水量接近真实值,砂土在区域验证中,模拟与实测差值为2.16%,整个模型模拟精度较好,能够准确地从时空上反演干旱半干旱地区1 m土体的土壤水分情况。  相似文献   

褐藻纲海带目Laminaria属和Saccharina属基于三个分子标记的系统发育分析     

CHI Shan  QIAN Hao  LI Tianyong  WANG Xumin  LIU Cui  REN Lei  TANG Xuexi  LIU Tao 《海洋学报(英文版)》2014,33(9):139-151

In the past two decades, many studies have focused on the classification within genus Laminaria, ultimately trying to divide it into two subgroups or genera: Laminaria and Saccharina. A significant debate still surrounds the question of its division, as the conflicting phylogenetic hypotheses that have resulted from the classification studies are based on different taxon sampling, molecular markers, or analysis methods. It is aimed at elucidate the molecular phylogeny within Laminaria and Saccharina. The nine species of Laminariales are sampled from northern Asia and Europe, and 23 new sequences in the nuclear, plastid, and mitochondrial genomes are determined to identify their taxonomic status. The phylogenetic analyses of 71 species are performed, including representatives from six of the seven families of the order Laminariales, based on three separate data sets. An evidence is provided to strongly support a clear split that maintains the two recognized genera, Laminaria and Saccharina, with Laminaria appearing to be the ancestor group. Further, analyses indicate that all taxa in Saccharina and Laminaria did not form a monophyletic lineage, instead Laminariaceae and Lessoniaceae grouped together interlacedly, and Costariaceae appeared as the sister taxon of the Lessoniaceae–Laminariaceae clade. In the phylogenetic analysis, mitochondrial c oxidase I(COI) sequences appeared to be the most credible molecular marker which was more befitting than nuclear encoded internal transcribed spacer(ITS) and plastid encoded rbcL for establishment of Laminariales systematics. It is the most comprehensive phylogeny of the order Laminariales, and contributes to an enhanced understanding and estimation of the phylogenetic relationships for the economically important seaweeds, Laminaria and Saccharina.  相似文献   

A Review of Aerosol Optical Properties and Radiative Effects          下载免费PDF全文

LIU Yuzhi  JIA Rui  DAI Tie  XIE Yongkun  SHI Guangyu 《Acta Meteorologica Sinica》2014,28(6):1003-1028

Atmospheric aerosols influence the earth's radiative balance directly through scattering and absorbing solar radiation, and indirectly through affecting cloud properties. An understanding of aerosol optical properties is fundamental to studies of aerosol effects on climate. Although many such studies have been undertaken, large uncertainties in describing aerosol optical characteristics remain, especially regarding the absorption properties of different aerosols. Aerosol radiative effects are considered as either positive or negative perturbations to the radiation balance, and they include direct, indirect (albedo effect and cloud lifetime effect), and semi-direct effects. The total direct effect of anthropogenic aerosols is negative (cooling), although some components may contribute a positive effect (warming). Both the albedo effect and cloud lifetime effect cool the atmosphere by increasing cloud optical depth and cloud cover, respectively. Absorbing aerosols, such as carbonaceous aerosols and dust, exert a positive forcing at the top of atmosphere and a negative forcing at the surface, and they can directly warm the atmosphere. Internally mixed black carbon aerosols produce a stronger warming effect than externally mixed black carbon particles do. The semi-direct effect of absorbing aerosols could amplify this warming effect. Based on observational (ground-and satellite-based) and simulation studies, this paper reviews current progress in research regarding the optical properties and radiative effects of aerosols and also discusses several important issues to be addressed in future studies.  相似文献   

国际标准海图的解析与三维显示研究     

盛佳良  郝多虎  何泉  吕铁硬  张超 《东北测绘》2014,(1):174-177

在．NET环境下,利用C#语言,研究并从底层实现了符合S-57规范的国际标准海图的解析,并将解析出的海图数据与遥感影像,DEM数据进行三维叠加显示,增强了海图显示的真实性,对于海图的应用与发展有一定的意义。  相似文献   

新疆尾亚韧性剪切带的基本特征及其意义     

邵铁全  刘云焕  董玉书 《地球科学与环境学报》2001,23(4):28-32

尾亚韧性剪切带形成于石炭纪晚期.根据其宏观变形构造、显微变形构造等变形特征,说明其经历了早期的推覆剪切和后期的右行推覆剪切两个主要演化阶段.对该区的构造演化及指导找矿增添了一点新的内容.  相似文献   

西天山博故图金矿床地质特征和资源潜力预测     

姚铁  周勇  杜展军  赵振明 《矿产与地质》2015,(1)

化探普查在西天山伊什基里克山东部发现一巨大金地球化学块体,对Au异常查证和评价发现了博故图金矿。金矿产于下石炭统大哈拉军山组地层中,赋矿岩石为流纹质火山碎屑岩、次火山岩和辉绿岩,金矿化与硅化、黄铁矿化关系密切。金矿体主要受区域大断裂及其次级断裂构造控制,与围岩无专属性,成因类型为浅成低温热液型。为查明金矿特征和成矿规律、扩大资源量,开展了地质、物化探综合方法找矿,在Ⅰ号矿区及东部邻区,激电测量和高精度磁测量发现多处异常,钻探验证发现了多条隐伏工业矿体,金资源量达大型。勘查结果表明博故图金矿区有很好找矿远景,找矿潜力巨大。  相似文献