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991.
Semi-two-dimensional numerical model for river morphological change prediction: theory and concepts 总被引:2,自引:2,他引:0
Tew-Fik Mahdi 《Natural Hazards》2009,49(3):565-603
This paper presents a new numerical model for river morphological predictions. This tool predicts vertical and lateral cross-section
variations for alluvial rivers, which is an important task in predicting the associated hazard zone after a flood event. The
Model for the HYdraulics of SEdiments in Rivers, version 1.0 (MHYSER 1.0) is a semi-two-dimensional model using the stream
tubes concept to achieve lateral variations of velocity, flow stresses, and sediment transport rates. Each stream tube has
the same conveyance as the other ones. In MHYSER 1.0, the uncoupled approach is used to solve the set of conservation equations.
After the backwater calculation, the river is divided into a finite number of stream tubes of equal conveyances. The sediment
routing and bed adjustments calculations are accomplished separately along each stream tube taking into account lateral mass
exchanges. The determination of depth and width adjustments is based on the minimum stream power theory. Moreover, MHYSER
1.0 offers two options to treat riverbank stability. The first one is based on the angle of repose. The bank slope should
not be allowed to increase beyond a certain critical value supplied to MHYSER 1.0. The second one is based on the modified
Bishop’s method to determine a safety factor evaluating the potential risk of a landslide along the river bank. 相似文献
992.
电网规划工作困境及前景展望 总被引:1,自引:0,他引:1
从能源规划、城市规划、科技进步三方面,分析了当前电网规划工作面临的主要困境和挑战,并对未来电网规划工作的前景做了展望。 相似文献
993.
Leaching Behavior of Fly Ashes from Power Plants 总被引:1,自引:0,他引:1
LIU Guijian GAO Lianfen ZHENG Liugen ZHANG Haoyuan PENG Zicheng School of Earth Space Science University of Science Technology of Chin Hefei Anhui Key Lab of Loess Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi''an Shaanxi 《《地质学报》英文版》2004,78(3):720-723
The Yanzhou mine district, located in southwestern Shandong Province, is about 1300 km2 with more than 8×109tons of proved coal reserves and there are 10 big power plants in this area. A large amount of coal ashes, which are regarded as waste materials, have been stockpiled in the area and have influenced the environment of the mine district. In this paper, analysis of fly ash samples from three power plants is carried out, the enrichment and concentration of trace elements, Pb, Zn, Cu and As, in coal ashes are analyzed, and petrological and mineralogical characteristics and chemical compositions of coal ashes are studied. The aim of this work is to provide basic scientific data for utilization of ashes and reduction of environmental pollutions. 相似文献
994.
995.
Francisco J. M. SIMOES Chih Ted YANG 《国际泥沙研究》2008,23(4):299-315
In part 1 of this two-paper series, a brief summary of the basic concepts and theories used in developing the Generalized Stream Tube model for Alluvial River Simulation (GSTARS) computer models was presented. Part 2 provides examples that illustrate some of the capabilities of the GSTARS models and how they can be applied to solve a wide range of river and reservoir sedimentation problems. Laboratory and field case studies are used and the examples show representative applications of the earlier and of the more recent versions of GSTARS. Some of the more recent capabilities implemented in GSTARS3, one of the latest versions of the series, are also discussed here with more detail. 相似文献
996.
Gray's Reef National Marine Sanctuary (GRNMS) is an increasingly popular site for recreational fishing and diving in the South Atlantic Bight (SAB). As a result, there has been heightened concern about potential accumulation of marine debris and its consequent effects on sanctuary resources. Field surveys were conducted at GRNMS in 2004 and 2005 to provide a spatially comprehensive characterization of benthic communities and to quantify the distribution and abundance of marine debris in relation to bottom features. The spatial distribution of debris was concentrated in the center of the sanctuary and was most frequently associated with ledges rather than other bottom types. On ledges, the presence and abundance of debris was significantly related to observed boating activity and physiographic features including ledge height, ledge area, and percent cover of benthic organisms. The results from this study will aid managers in optimizing cleanup efforts and long-term monitoring of debris accumulation patterns at GRNMS and other hard bottom areas in the SAB. 相似文献
997.
998.
本文介绍了ADCP高频大功率声发射机的D类功率放大器。该放大器采用大功率VMOS场效应管作为功放输出级,高压供电,电路简单,调试方便。具有工作频率高,输出功率大的特点。特别适合于船用。 相似文献
999.
地质现象分形统计学研究的若干问题 总被引:10,自引:1,他引:9
摘 要 要发展分形理论在地质科学中的应用就必须加强对地质现象分形统计学的研究。
文中对地质现象分形统计学的概念、意义、内容、方法和一般步骤作一概略论述。同时对
分形概念的拓广、分维求法及意义、幂律问题、分数布朗运动、方位 分维估值法等问题也作
了初步的探讨。 相似文献
1000.
Yu Chongwen 《中国地质大学学报(英文版)》1999,10(1):2
Threefundamentaltheoriesareraisedfor“complexityandself-organizedcriticality(SOC)ofmetalogenicdynamicsystems”(Yu,1998):(1)Nonl... 相似文献