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排序方式: 共有166条查询结果,搜索用时 15 毫秒
1.
2.
Cheng-Chien Liu Richard L. Miller Kendall L. Carder Zhongping Lee Eurico J. D’Sa James E. Ivey 《Journal of Oceanography》2006,62(3):235-248
We present a new approach that incorporates two models to estimate the underwater light field from remote sensing of ocean
color. The first employs a series of analytical, semi-analytical, and empirical algorithms to retrieve the spectrum of inherent
optical properties (IOPs), including the absorption and the backscatter coefficients, from the spectrum of remote sensing
reflectance. The second model computes the profile of photosynthetically available radiation E
0,PAR
(z) for a vertically homogeneous water column using the information of the retrieved IOPs and the ambient optical environment.
This computation is based on an improved look-up table technology that possesses high accuracy, comparable with the full solution
of the radiative transfer equation, and meets the computational requirement of remote sensing application. This new approach
was validated by in situ measurements and an extensive model-to-model comparison with a wide range of IOPs. We successfully mapped the compensation
depth by applying this new approach to process the SeaWiFS imagery. This research suggests that E
0,PAR
(z) can be obtained routinely from ocean-color data and may have significant implications for the estimation of global heat
and carbon budget. 相似文献
3.
Evaluation of bending moments and shear forces at unit connections of very large floating structures using hydroelastic and rigid body analyses 总被引:1,自引:0,他引:1
Byoung Wan Kim Sa Young Hong Jo Hyun Kyoung Seok Kyu Cho 《Ocean Engineering》2007,34(11-12):1668-1679
This paper investigates the characteristics of bending moments, shear forces and stresses at unit connections of very large floating structures (VLFS) under wave loads. The responses of VLFS are calculated by solving multi-body motion equation considering hydroelasticity and connection stiffness. Hydroelastic responses are calculated by the direct method. Higher-order boundary element method (HOBEM) is used for fluid analysis and finite element method (FEM) is introduced for structural analysis. The equation of motion is modified to describe the unit connections by employing spring elements. Bending moments and shear forces at the connections are obtained from the dynamic equilibrium condition for pressures and inertia forces. Two types of VLFS units such as tandem arranged units and side-by-side arranged units are considered in the numerical examples. The influences of connection stiffness, wave frequency and heading angle on responses of VLFS are investigated through the numerical examples. Rigid body analysis along with hydroelastic analysis is also carried out in the numerical analysis and comparison of those two approaches is discussed. 相似文献
4.
本文主要叙述了在开发煤矿地质信息系统(CMGIS)中的几种主要地质图件的数据存贮与处理技术。地质图件作为一种专业图件,有它特有的属性,如岩性花纹符号的大量出现,各种构造、地物等特殊线条的出现,地质曲线与文字标注的大量出现等。实践表明,采用商品化通用软件包(Auto CAD)已满足不了用户的要求,因为它缺乏地质上所需要的特殊性线型。用它编辑后的图形数据难以二次利用,图素的地质含义不再表现在图形数据库中,况且,如果图形编辑量过大,还必须考虑是否要对原始数据进行调整或增加辅助数据,为此,用户必须在不同的软件环境下运行不同的软件和数据,造成用户学习掌握和使用上的困难。 相似文献
5.
地质符号的计算机图形学定义 总被引:2,自引:2,他引:2
萨贤春 《物探化探计算技术》1997,19(1):90-96
地质符号一般均有其特定的图形特征和表示意义,用以表达地质制图中所涉及的具体或抽象的地质对象。本文对地质符号(尤其是岩性符号)的有关计算机图形学方法进行了分析和比较,并在对各种地质符号的分析研究基础上提出了一种地质符号(岩性符号)的计算机图形学定义的新的综合性方法—图元组合法及其分区编码方案 相似文献
6.
7.
Sa’ad Zeki Abdul-Kader Al-Mashaikie Suhad Kalaf Abdul-Razzak Madhat Eliwie Naser 《Arabian Journal of Geosciences》2016,9(19):723
The Baluti Formation is exposed succession of the Rhaetian age (Upper Triassic). These strata are interpreted herein for the first time to redeposit in a deep marine setting (distally steepened carbonate ramp/medial to distal slope) on the northwestern margin of the Neo-Tethys. The Galley Derash section is apparently continuous with no evidence for either subaerial exposure or submarine erosion. The absence of erosional scours in the study area confirms emplacement of these strata below both fair-weather and storm wave base. Event beds, particularly those resulting from sediment gravity flows, dominate the Rhaetian interval. The Upper Rhaetian strata are primarily assigned to the Galley Derash Valley. It records an upward transition from moderate-scale, olistolith-bearing debris flow deposits (debrite) to medium-/thin-bedded turbidites remobilized as sediment slumps/slides. The succession is dominated by medium- to thin-bedded calcareous turbidites and hemipelagic suspension deposits. Very low fossil assemblages, particularly stromatolite fragments, and planktonic bivalves occur within some intervals in the section. Rapid and relatively continuous sedimentation is attested to by the thickness of the section, the abundance of calcareous turbidites, and the thin nature of the intercalated hemipelagic beds. Low content of badly preserved fossils and evidence of continuous and rapid sedimentation refer to alteration by tectonic disturbances or diagenesis. This makes the Baluti Beds as a supplementary section for the Rhaetian successions in Iraq. 相似文献
8.
9.
Osman Günay Müslim Murat Saç Mutlu İçhedef Caner Taşköprü 《Arabian Journal of Geosciences》2018,11(9):213
In this study, soil radon levels have been measured for the first time across the Ganos fault (GF), which is known as the western part of the North Anatolian Fault Zone. LR 115 Type 2 Solid State Nuclear Track Detectors (time integrated) have been applied to determine soil gas radon levels, and the survey was performed in 16 stations along the fault line. The results showed that soil gas radon concentrations and variation of concentration levels are comparable high along the fault line. It is also observed that in the middle of the Ganos Fault, fairly elevated radon levels were detected. These can be related to the activity of the fault lines. It is confirmed that the study area has a very active tectonic structure and is great location for analyzing radon variations. 相似文献
10.
目前没有规范给出串锚的水平承载力计算公式,为了利用有限元法研究串锚水平承载力特性,采用相关理论计算以及室内试验的方法来验证有限元法模拟计算的可靠性。实践证明,有限元法具有较高的计算精度。利用有限元分析软件ABAQUS建立了串锚-土体模型,模拟串锚在水平荷载作用下破坏过程,研究了串锚在水平荷载作用下破坏机理,从而得到了串锚水平承载力特性。在相同的工况条件下,串锚的水平承载力与其锚链长度有关,在一定范围内,增加锚链的长度可以提高串锚的水平承载力;串锚的水平承载力不是相应的单个锚的水平承载力相加,其水平承载力小于相应的单个锚水平承载力之和,在进行串锚水平承载力设计计算时应给与相应的考虑。 相似文献