闭合导线测量中边长系统误差分析   总被引：1，自引：1，他引：0  

党四效 《海洋测绘》2004,24(2):41-42

在闭合导线测量中,导线边如果存在系统误差,其解算结果仍可能满足现行规范中的各项精度指标。通过一项边长接近的闭合导线测量实例,分析了产生误差的原因与对策,解算出符合要求的测量成果。  相似文献   

The concept of an estuary: A definition that incorporates systems which can become closed to the ocean and hypersaline     

Ian C. Potter  Benjamin M. Chuwen  Steeg D. Hoeksema  Michael Elliott 《Estuarine, Coastal and Shelf Science》2010

The majority of the definitions of estuaries have been based on the characteristics of estuaries in temperate regions of the northern hemisphere. As previously pointed out (Day, 1980), such definitions do not take into account such features as periodic closure of their mouths and hypersaline conditions during dry periods, which characterise many estuaries in southern Africa and south-western Australia. There is also ambiguity as to whether an estuary sensu stricto must be fed by a river. The following definition was developed to encompass the main characteristics of all estuaries: An estuary is a partially enclosed coastal body of water that is either permanently or periodically open to the sea and which receives at least periodic discharge from a river(s), and thus, while its salinity is typically less than that of natural sea water and varies temporally and along its length, it can become hypersaline in regions when evaporative water loss is high and freshwater and tidal inputs are negligible. Estuaries are thus regarded as unique ecosystems, which, in the case of fishes, for example, are occupied by species that collectively represent a particular suite of guilds.  相似文献   

海州露天矿滑坡灾害统计分析及信息库建立     

何峰  王来贵  王振伟 《地质灾害与环境保护》2006,17(2):61-63

露天矿边坡稳定性受工程地质、水文地质条件和人工活动等因素的影响,这些因素决定了发生滑坡的可能性。然而,上述因素与发生滑坡之间很难找到某种确切的关系。海州矿非工作帮边坡从建矿到目前,已发生过80多次滑坡,规模较大且有详细资料记录的滑坡60多次。将这些滑坡资料进行整理,通过统计分析来建立灾害信息库,以便对边坡的稳定性做出定性评价,并为提出闭坑环境地质灾害预警系统提供依据。  相似文献   

节水钻探新技术及球体冲击器研究   总被引：1，自引：0，他引：1  

卢春华  鄢泰宁  Н.Γ.叶戈罗夫  蒋国盛  吴翔  LU Chun-hu  YAN Tai-ning  Н Γ Egorov  JINAG Guo-sheng  WU Xiang 《地质与勘探》2006,42(2):93-96

传统的钻进工艺要消耗大量的地表水,在干旱缺水地区钻探经常会遇到缺水问题.介绍了一种节水钻探新技术,论述了其工作原理,室内外试验表明该技术能够达到既大量节水又提高钻进效率的目的.在此基础上介绍了一种用于软-中硬岩层中回转冲击钻进的新型球体冲击器的结构、工作原理以及大幅度提高机械钻速并降低成本的试验效果.  相似文献   

南沙群岛封闭环礁空间结构演化的遥感复合信息与模型Ⅰ     

刘宝银  王岩峰 《海洋学报》1998,20(2):43-51

就南沙群岛封闭环礁发育生长及其区域局限性的特征,与其所表观的遥感信息进行了复合分析.随后,以封闭环礁形成的机制、发育规律与时-空分布,建立了封闭环礁概念化一遥感系统,并以该系统对封闭与准封闭环礁的信息函数值、均衡度值求解,对两类环礁发育形态进行拓扑分析,由此为封闭与准封闭环礁演化的可比性模型提供基础依据.  相似文献   

一种使用卫星高度计数据且基于密度聚类的新型海洋中尺度涡自动探测算法     

李蓟涛  梁永全  张杰  杨俊刚  宋平舰  崔伟 《海洋学报(英文版)》2019,38(5):134-141

中尺度涡旋是海洋中典型的中尺度现象,是海洋中能量传递的运输者,中尺度涡识别与提取是物理海洋学研究的重要内容之一,而中尺度涡自动发现算法是最基础的用于寻找与分析中尺度涡的工具。中尺度涡旋探测工作的数据来源主要为卫星高度计数据融合出的SLA数据,该数据可以客观的描述海洋表层高度状态。中尺度涡表示为SLA闭合等值线所包围的局部等值区域,涡旋识别需要从SLA数据中提取出稳定的闭合等值线结构。针对基于SLA数据中的中尺度涡探测的特点,本文提出了一种新的基于聚类方法的中尺度涡自动识别算法,通过对SLA数据集的分割与筛选将中尺度涡区域与背景区域分离,后建立区域内联系并将其映射到SLA地图上来提取中尺度涡结构。本文算法解决了传统探测算法中参数设定的敏感性问题,不需要进行稳定性测试,算法适应性增强。算法中加入了涡旋筛选机制,保证了结果的涡旋结构的稳定性,提高了识别准确率。在此基础上,本文选取了西北太平洋及中国南海地区进行了中尺度涡探测实验,实验结果展示出了本文算法在较传统算法提高算法效率的同时,也保持着较高的算法稳定性,可以在稳定识别各个单涡结构的同时识别稳定的多涡结构。  相似文献   

The influence of prolonged mouth closure on selected components of the hyperbenthos in the littoral zone of the temporarily open/closed Kasouga Estuary,South Africa     

P.W. Froneman  T.O. Henninger 《Estuarine, Coastal and Shelf Science》2009

The influence of prolonged mouth closure on the population dynamics of the caridian shrimp, Palaemon peringueyi and the estuarine isopod, Exosphaeroma hylocoetes, in the littoral zone of temporarily open/closed Kasouga Estuary located on the south-eastern coastline of southern Africa was assessed monthly over the period October 2007 to September 2008. Prolonged mouth closure of the estuary contributed to hypersaline conditions (psu > 35) prevailing throughout the estuary for the last four months of the study. The high salinities coincided with a decrease in the areal extent (up to 80%) of the submerged macrophytes, mainly Ruppia maritima, within the littoral zone of the estuary. Total abundance and biomass values of the shrimp and isopod over the period of investigation ranged from 0 to 14.6 ind m⁻², from 0 to 13.3 mg dwt m⁻², from 12 to 1540 ind m⁻² and from 0.1 to 2.16 mg dwt m⁻², respectively. Maximum values of both the shrimp and isopod were recorded in the upper reaches of the estuary in close association with R. maritima. Over the course of the investigation, both the abundance and biomass values of the shrimp decreased significantly (P < 0.05 in both cases) which could be related to reduced habitat availability, R. maritima, that acts as a refuge against fish predation. Additionally, the decrease in abundance and biomass values could be attributed to reduced recruitment opportunities for the shrimp and the cessation of reproduction in the estuarine isopod. The establishment of a link to the marine environment following an overtopping event in September 2008 contributed to a decrease in salinity within the system although no recruitment of either the isopod or shrimp was recorded.  相似文献   

构造生烃     

熊斌辉 《海洋地质译丛》2009,(2):1-9

生烃是岩石中所含的有机质产生流体有机化合物的化学反应。岩石有机质化学反应存在两种系统：封闭系统和开放系统,随着埋深加大,烃源岩越来越致密,岩石的化学反应逐渐由开放系统转变为封闭系统。目前的生烃理论仅仅是开放系统下烃源岩成熟与生烃理论,烃源岩成熟与生烃是不匹配的。封闭系统下烃源岩成熟与生烃是不匹配的,烃源岩成熟但不生烃,而是形成另外一种成熟的固体有机质。大多数情况是烃源岩为半封闭系统,烃源岩处于欠生烃状态。构造运动形成的断层和裂隙将烃源岩与疏导层沟通,烃源岩迅速由封闭、半封闭系统转变为开放系统。这种生烃系统的转变形成短时间内过量生烃,笔者将这种生烃作用命名为构造生烃,意味着构造运动期即为主生烃期,伴随着多次构造运动可以形成多个幕式生烃高峰。构造生烃理论开拓两个极其重要的勘探领域：第一,新构造勘探。以往认为已经过了生、排烃期的构造得以解放,如渤海湾郯庐断裂带第四纪圈闭不是过了主生烃期,而是正处于构造生烃的过生烃高峰期。以PL19-3为代表的油气运聚强度只有构造生烃能够解释;第二,超深勘探,特别是天然气勘探。深层勘探的下限将大大延伸,生烃门限,特别是生气门限将大大加深,仅生烃而言万米都不是天然气勘探的极限。  相似文献   

Stability of earth slopes. Part II: three dimensional analysis in closed‐form     

Lysandros Pantelidis  D.V. Griffiths 《国际地质力学数值与分析法杂志》2013,37(13):1987-2004

A closed‐form stability analysis of earth slopes performed in 3D is proposed. The sliding surface is assumed spherical and treated as a rigid body allowing the internal state of stress to be ignored. The proposed closed‐formed solution (CFS) can be applied to both homogenous and non‐homogenous slopes of either simple or complex geometry and can also deal with any kind of additional loading. Although it is recognized that the critical failure surface is often non‐spherical, the CFS methodology for spheres described herein provides an objective tool for the evaluation of the assumptions made by other limit equilibrium methods including the role of intercolumn forces. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

煤岩、泥岩密闭体系下热解产物特征及动力学分析     

王民  卢双舫  吴朝东  王伟明 《沉积学报》2011,29(6):1190-1198

通过密闭体系热模拟实验考察了煤岩和泥岩产物产率及动力学特征,结果表明高温阶段甲烷的来源除了重烃气的裂解外,还有有机质直接裂解的贡献。泥岩有机质在初次裂解过程中易于生甲烷的组分较少且热稳定性要高,煤岩有机质在初次裂解过程中易于生甲烷的组分相对较多且稳定性较弱。煤岩在低温阶段热解的液态烃中正构烷烃通过环化和芳香化作用与沥青...  相似文献