Virtual Huanghe River System： Framework and Technology   总被引：2，自引：0，他引：2  

LU Heli LIU Guifang SUN Jiulin 《中国地理科学(英文版)》2006,16(3):255-259

1 Introduction Huanghe (Yellow) River basin is located in 32°–42°N, 96°–119°E. The area of the catchment is more than 752,000km2. The river is 5464km long with a drop in elevation of 4830m. Among the whole area, the moun- tainous and stone area accounts for 29%, loess and hills area 46%, sandy area 11% and plain area 14%, respec- tively. Different natural landscapes exist in this area. The Huanghe River flows through the Loess Plateau, where the soil is eroded seriously (Wang, 2002;…  相似文献   

Morphology and Luminosity Segregations in Galaxy Groups     

M. Girardi  F. Mardirossian  M. Mezzetti  E. Rigoni 《Astrophysics and Space Science》2003,285(1):31-35

We study morphology and luminosity segregation of galaxies in groups. We analyze the two catalogs of (∼2×400) groups which have been identified in the Nearby Optical Galaxy sample, by means of hierarchical and percolation `friends-of-friends' methods. We find that earlier-type (brighter) galaxies are more clustered and lie closer to the group centers, both in position and in velocity, than later-type (fainter) galaxies. Spatial segregations are stronger than kinematical segregations. These effects are generally detected at the ≳3-sigma level, with the exception of morphological segregation in velocity, which is the weakest effect. Our main results are confirmed by the analysis of statistically more reliable groups (with at least five members), and are strengthened by the detection of segregation in both hierarchical and percolation catalogs. Luminosity segregation is shown to be independent of morphology segregation. Our conclusions agree with a continuum of segregation properties of galaxies in systems, from low-mass groups to massive clusters. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

板翅式换热器综合性能优化的设计方法     

高俊忠  陈维汉 《广东海洋大学学报》2003,23(6):45-49

应用给定换热器结构材料而使换热量最大的两侧换热表面的最佳匹配准则和使可用能损失率最小的最佳运行参数准则。利用两个准则间的关系 ,采用迭代的方式完成换热器的优化设计 ,使换热器的设计达到材料省、换热效果好及运行费用低的目的 ,且能在设计阶段实现。  相似文献   

A photometric study of the polar ring galaxy UGC 5600     

G. M. Karataeva  V. A. Yakovleva  V. A. Hagen-Thorn  O. V. Mikolaichuk 《Astronomy Letters》2001,27(2):74-80

We analyze our BVR _c photometry for UGC 5600, a candidate polar ring galaxy, obtained with the 6-m telescope. We have confirmed the existence of an inner polar ring and show that the outer ring-shaped structure represents spiral arms; i.e., UGC 5600 belongs to the rare class of gas-rich spiral galaxies with inner polar rings.  相似文献   

Behavior of Pile Groups under Lateral Load   总被引：2，自引：0，他引：2  

Yang Keji  Li Qixin Wang Fuyuan Associate Proferssor  Hehai University  Nanjing Engineer  Hehai University  Nanjing 《中国海洋工程》1991,(2)

Based on investigation and model tests, and in combination with the research work on group effect for pile groups under lateral loads relating to the code of fixed offshore platforms, a series of studies have been performed on the behavior and failure mechanism of laterally loaded pile groups, critical pile spacing inducing group effect, lateral bearing capacity of pile groups and its main influence factors, the stress-strain relationship for single piles and pile groups and so on. Some new laws about non-uniformity of load distribution in the longitudinal direction of pile groups and load-deflection (p - y) curves for pile groups have been discovered, and an empirical formula is presented in order to remedy the defect of current calculating methods at home and abroad. These results can be used for reference in the design of pile foundation under lateral loads.  相似文献   

Three-dimensional Layer-integrated Modelling of Estuarine Flows with Flooding and Drying   总被引：1，自引：0，他引：1  

B. Lin  R.A. Falconer 《Estuarine, Coastal and Shelf Science》1997,44(6):737-751

Details are given of the refinement and application of a thee-dimensional (3-D) layer-integrated numerical model of tidal circulation, with the aim of simulating severe tidal conditions for practical engineering applications. The mode splitting strategy has been used in the model. A set of depth-integrated 2-D equations are first solved to give the pressure gradient, and the layer-integrated 3-D equations are then solved to obtain the vertical distributions of the flow velocities. Attention has been given to maintaining consistency of the physical quantities derived from the 2-D and 3-D equations. A TWO=layer mixing length turbulence model for the vertical shear stress distribution has been included in the model. Emphasis has been focused on applying the model to a real estuary, which is geometrically complicated and has large tidal ranges giving rise to extensive flooding and drying. The model has been applied to three examples, including: wind-driven flow in a rectangular lake, tidal circulation in a model rectangular harbour, and tidal circulation in a large estuary. Favourable results have been obtained for both the simple and complex flow beds.  相似文献   

香港附近海区台风波浪的波群统计分析     

黎满球 《热带海洋学报》1994,(4)

根据香港附近海区１９８５，１９８６年两次台风大浪的实测资料，以有效波高为相应水平，对波群作统计分析，得出可供海洋工程参考的波群连长、波群重复长度、波群出现频率以及波群中最大波高与有效波高的关系等。并将统计值与理论值作比较，结果表明：统计值大于“连”的理论值，而与包线理论中采用合田修正公式的汁算值相近。  相似文献   

Statistics of nonlinear wave crests and groups   总被引：1，自引：0，他引：1  

M. Aziz Tayfun   《Ocean Engineering》2006,33(11-12):1589-1622

Groups of large nonlinear waves with sharper higher crests can pose hazards to ships, induce harbor resonance and cause wave-overtopping of fixed and floating structures. Past interest in wave groups has mostly been focused on the statistics and modeling of linear wave groups. Studies on nonlinear wave groups are surprisingly few, and address deep water waves only. Here, statistics of nonlinear wave crests and wave-crest groups in deep and transitional water depths are considered, using an appropriate second-order representation for crest heights and the continuous wave-envelope approach. In particular, theoretical expressions describing the statistics of nonlinear wave crests and their groups are posed in the form of a simple second-order transformation of well-known results on linear waves. Predictions from the transformation so posed compare well with nonlinear wave data gathered in the North Sea, and demonstrate that nonlinearities do affect the statistics of large wave crests and their groups significantly.  相似文献   

莱西市水资源管理系统的人机互动功能     

齐勇  于诰方  李寿田  孙秀竹  胡翠红 《海洋湖沼通报》2007,(2):142-146

本文结合莱西市水资源管理的基本特性,采用人机交互管理方式,成功地运用地理信息系统(GIS),实现了界面良好的莱西市水资源信息系统的各种功能,为规范水资源业务管理的程序、开展地区水资源管理信息系统化建设,提供了有力的技术支持。  相似文献   

Modelling linear wave transformation induced by dissipative structures—Random waves     

R. Silva  M.A. Losada  P. Salles 《Ocean Engineering》2006,33(16):2174-2194

The relevant theory is presented and numerical results are compared with the analytical solution for the interaction of non-breaking waves with an array of vertical porous circular cylinders on a horizontal bed. The extension to the cases of unidirectional and multidirectional waves is obtained by means of a transfer function. The influence of the mechanical properties of porous structures and wave irregularity on wave transformation is analysed. Results for unidirectional and multidirectional wave spectra are compared to those obtained for regular waves. The model presented reproduces well the analytical results and provides a tool for analysing several engineering problems.  相似文献