SIMULATION OF POLLUTANTS IN RIVER SYSTEMS USING FINITE DIFFERENCE METHOD     

ZAHEER Iqbal  CUI Guang Bai Ph D candidate  College of Water Resources  Environment  Hohai University  Nanjing  China E-mail: zaheeriqbal@hotmail.com Prof. College of Water Resources  Environment  Hohai University  Nanjing  China 《国际泥沙研究》2002,17(2)

1 INTRODUCTION Numerical computation provides an easily extended and user-friendly environment with computer aided programming for the simulation of pollutants in river systems. In the most of water quality assessment and monitoring problems during water pollution control and environmental impact assessment studies of river systems, mathematical modeling has been playing a key role for the last two decades. The majority of existing water quality models are the mechanistic and are based o…  相似文献   

《作者来信》     

金振民  章军锋  H.W.GreenⅡ  金淑燕 《中国科学D辑》2002,(2)

中国科学（D辑）编辑部:贵刊中文版2001年第31卷12期第969～976页发表了我们的文章,题目为《大洋深俯冲流变性质及其地球动力学意义——来自地幔岩高温高压实验的启示》,该文利用了“Geology”2001年29卷第  相似文献   

Investigation of Curie Point Depth in Sulu Ultrahigh-Pressure Metamorphic Belt,Eastern China     

乔庆庆  刘庆生  邱宁  付媛媛  赵素涛  吴耀  杨涛  金振民 《中国地质大学学报(英文版)》2008,19(3)

The Curie point depth of continental crust can reflect the regional tectonic pattern and geothermal structures. Analysis of magnetism is an efficient way to obtain the Curie point depth on a regional scale. This study systematically investigated the Curie point depth of Sulu (苏鲁) ultrahigh pressure (UHP) metamorphic belt (33°40'N to 36°20'N and 118°E to 120°E, ca. 60 000 km2), eastern China using aeromagnetic data. The results show that the Curie point depth of the Sniu region varies from 18.5 to 27 kin. The shallowest Curie point depth (ca. 18.5 km) is located in Subei (苏北) subsidence, where the estimated temperature gradient value is about 31.35℃/kin, which is comparable with the measured value of 30℃/krn. In addition, a two-dimensional numerical solution of the heat conduction was used to calculate the temperature field to a depth of 30 km along the profile from Tancheng (郯城) to Lianshui (涟水) with a length of 139 km. The steady state model solved using the finite element method shows that the temperature around the Curie point depth is about 585.36℃, which is close to the Curie temperature (580 ℃) of magnetite at atmospheric pressure. These results provide new insights into the tectonic and continuous thermal structures of the Sulu UHP metamorphic belt.  相似文献   

广西平南玄武岩的地球化学特征   总被引：4，自引：0，他引：4  

孔华  黄德志  金振民 《大地构造与成矿学》2000,24(4):342-349

平南碱性玄武岩产于 NE向的区域性断裂中 ,岩石类型有两类 ,一为碧玄岩 ,全岩 K- Ar年龄为 50 .8Ma,含各类包体 ,有以下特征 :1)含地幔岩包体 ,2 ) [Mg]=0 .78,3)在 Fe O/mol- Mgo/mol图解上液相线橄榄石的成分位于 Fo90～ Fo94之间 ,与橄榄岩包体中的橄榄石成分完全一致。4 ) Ni=0 .0 4 ( % ) <0 .0 5( % ) ,5)其熔浆密度为 2 .62 g/cm3,粘度为 2 .52 Pa· s,携带 4 cm直径包体上升的速度为 37.7cm/s,上升的速度较快 ,具原生碧玄岩浆的特点 ,岩浆液相线的温度为12 86℃ ,起源压力为 1.8GPa,玄武岩富集轻稀土可能与地幔性质有关。一为粗面玄武岩 ,不含包体 ,全岩 K- Ar年龄为 4 9.9Ma,岩浆液相线的温度为 1162℃ ,是进化岩浆。玄武岩的 Nd、Sr同位素显示为亏损地幔源区。它们都是大陆拉张环境下的产物 ,与中国东部新生代玄武岩的形成背景一致。  相似文献   

The influences of environmental factors on the air-sea coupling coefficient     

Yanmin Zhang  Yifan Wang  Yunhua Wang  Yining Bai  Chaofang Zhao 《海洋学报(英文版)》2022,41(2):147-155

The response relationship between equivalent neutral wind speed anomaly(ENWSA) and sea-air temperature difference anomaly(SATDA) has been analyzed over four typical sea regions, i.e., the Kuroshio Extension, the Gulf Stream, the Brazil-Malvinas Confluence and the Agulhas Return Current. The results show that ENWSA is more sensitive to SATDA than sea surface temperature anomaly(SSTA), which implies that SATDA seems to be a more suitable parameter than SSTA to analyze the mesoscale air-sea interac...  相似文献   

大别山超高压榴辉岩流变强度——评论与答复     

宋鸿林  金振民等 《地球科学》2003,28(2):232-234

1　评论在阅读了《地球科学》2 0 0 1年第 6期中金振民等[1 ] 的关于榴辉岩高温高压下流变实验的文章后 ,觉得有几个问题值得向作者请教 .( 1 )实验样品是否达到了晶体塑性变形的稳态蠕变状态 .确定流变强度的重要标准是实验样品是否达到了稳态蠕变状态 .虽然 ,从应力 /应变曲线看 ,多数样品似乎达到了平坦的曲线 ,但从该文中所附的显微照片 (原文图 2 )看不出反映稳态流变的构造特征 .变形前后的显著变化有 :①粒度明显增大 ,绿辉石和石榴石的粒度达 1 0 0～ 1 5 0 μｍ ,为原样品的2～ 3倍 .(中、英文版的同一ＧＢ1 92照片所注的比例尺相…  相似文献   

利用超高压变质岩的P波速度估算地下岩石的热导率   总被引：3，自引：0，他引：3  

欧新功  金振民  夏斌  徐海军  金淑燕 《地球科学》2006,31(4):564-568

岩石热导率是了解地球内部热传导过程的重要参数之一, 但热导率的测量在室内和野外都比较复杂.如何利用容易获得的岩石物理参数(如超声波速度) 来估算岩石的热导率就显得非常重要.通过对中国大陆科学钻探(CCSD) 主孔655件样品热导率和超声波速度的相关分析, 把样品分为新鲜榴辉岩、退变质榴辉岩、副片麻岩和正片麻岩4类, 并分别建立了利用岩石P波速度估算热导率的计算方程.回归计算表明, 榴辉岩热导率和P波速度之间的相关性较大, 相关系数在0.7左右, 片麻岩显示的相关系数比较小, 在0.4~0.5之间.鉴于样本数量较大, 这种结果足以表明热导率和P波速度之间可以用给定的线性关系来表达.为了检验获得的方程, 在CCSD主孔中选取典型的岩性单元, 利用测得的P波速度估算相应的热导率, 结果显示估算值和实测热导率平均值非常接近, 表明利用P波估算岩石热导率的方程是可行和实用的, 为本区和相似地区大地热流和热结构计算提供了热导率的计算方法和依据, 因而具有重要的岩石物理学和地球物理意义.   相似文献   

Error control of iterative linear solvers for integrated groundwater models     

Dixon MF  Bai Z  Brush CF  Chung FI  Dogrul EC  Kadir TN 《Ground water》2011,49(6):859-865

An open problem that arises when using modern iterative linear solvers, such as the preconditioned conjugate gradient method or Generalized Minimum RESidual (GMRES) method, is how to choose the residual tolerance in the linear solver to be consistent with the tolerance on the solution error. This problem is especially acute for integrated groundwater models, which are implicitly coupled to another model, such as surface water models, and resolve both multiple scales of flow and temporal interaction terms, giving rise to linear systems with variable scaling. This article uses the theory of "forward error bound estimation" to explain the correspondence between the residual error in the preconditioned linear system and the solution error. Using examples of linear systems from models developed by the US Geological Survey and the California State Department of Water Resources, we observe that this error bound guides the choice of a practical measure for controlling the error in linear systems. We implemented a preconditioned GMRES algorithm and benchmarked it against the Successive Over-Relaxation (SOR) method, the most widely known iterative solver for nonsymmetric coefficient matrices. With forward error control, GMRES can easily replace the SOR method in legacy groundwater modeling packages, resulting in the overall simulation speedups as large as 7.74×. This research is expected to broadly impact groundwater modelers through the demonstration of a practical and general approach for setting the residual tolerance in line with the solution error tolerance and presentation of GMRES performance benchmarking results.  相似文献   

The Multi-Wavelength Quasar Survey Ⅳ. Quasars in the Leo Cluster     

Yang Chen Yu Bai Xiang-Tao He Jiang-Hua Wu Jing Wang Qing-Kang Li Yan-Chun Sun Richard F. Green Wolfgang Voges 《中国天文和天体物理学报》2007,7(4):595-600

We aim to provide a quasar sample that is more complete than any previous surveys by using a combined selection technique to reduce the selection effects. Here we present the observational results for the X-ray candidates in the field of the Leo Cluster. We found 33 X-ray AGNs in this field of which 10 are new discoveries. The X-ray data and optical spectra of these AGNs are given. We also study the near-IR properties of the X-ray-selected AGNs by using the data from 2MASS. Most of the AGNs in our sample span the color range 0.0〈B-J〈2.5,1.0〈 J-Ks 〈2.0 and 0.5〈H-Ks〈1.2.  相似文献   

西南印度洋洋盆演化和岩浆地球化学印迹          下载免费PDF全文

李伟  金振民  陶春辉 《沉积与特提斯地质》2021,41(2):218-231

西南印度洋中脊(SWIR)平均扩张速率约为14 mm/yr,是全球洋中脊系统的重要组成端元,因其具有慢速-超慢速扩张特征,引起全球科学家的广泛关注。基于前人对SWIR的综合研究成果,从构造和岩浆作用两个角度出发,系统地回顾了SWIR的形成和演化历史,探讨了岩浆的分布特征和地幔不均一性成因。SWIR的形成始于冈瓦纳大陆的裂解,中段洋脊区域(26～42°E)是印度洋最早开启的窗口,历经多次洋脊跃迁和扩展作用形成了斜向扩张展布,多分段的构造格局。地幔热点在冈瓦纳大陆裂解过程中扮演了关键角色,并对SWIR的洋底地貌和岩浆作用具有显著影响,其中Bouvet和Marion热点在SWIR的西段和中段岩浆均留下了地球化学印迹。SWIR西段岩浆除却Bouvet热点影响之外表现出与大西洋-太平洋型玄武岩相似的同位素地球化学特征。在SWIR中段,39～41°E附近的岩浆具有显著的DUPAL异常特征,与冈瓦纳大陆的初始形成、裂解紧密相关。受俯冲改造的中—新元古代的造山带岩石圈地幔拆沉是造成SWIR中段地幔不均一性的重要根源。在SWIR东段,46～52°E区域内的局部岩浆组成异常,推测具有大陆地壳物质混染的成因。而在Melville转换断层以东,洋脊形成时间最晚,玄武岩的地幔源区受到了富集组分的交代作用,其同位素组成与相邻的中印度洋中脊(CIR)和东南印度洋中脊(SEIR)地幔源区具有亲缘性。  相似文献