闸控河网水文-水动力-水质耦合数学模型——Ⅱ.应用          下载免费PDF全文

陈炼钢  施勇  钱新  金秋  赖晓珍  王帅 《水科学进展》2014,25(6):856-863

针对中国多闸坝重污染河流的典型代表——淮河中游河网,为提高其流域水环境预警及应急响应能力,依据水文-水动力-水质耦合数学模型DHQM(Hydrology, Hydrodynamics, and Water Quality Model )的理论框架,构建了由淮河干流、沙颍河和涡河3个一维模块和鲁台子、蚌埠闸2个二维模块组成的淮河中游河网水文-水动力-水质耦合数学模型.采用经过验证的模型针对一个虚拟的水污染事故情景,分析了不同调度方案与淮河干流来水组合下污染团下泄对下游水质的影响;并以保障淮河干流蚌埠市饮用水源地的取水水质安全和减轻事故对下游水质的影响程度为目标,优选出分期小流量慢速下泄污染水体为最佳的水量水质联合应急调度方案.  相似文献   

基坑支护中土钉内力计算方法对比分析     

陆峰  颜荣华  朱明 《岩土工程技术》2014,(3):113-116

大量足尺模型试验和实地监测结果表明,土钉支护中土钉内力具有开挖效应,土钉最大拉力出现在基坑中部,上部和下部内力均较小.规范《建筑基坑支护技术规程》（JGJ 120-99）及《基坑土钉技术规程》 （CECS 96∶97）的设计计算理论均不能准确反映土钉墙现场原型观测中实际土钉力,以上问题给合理确定土钉长度带来困难,使计算土钉力及确定长度更多依靠经验,造成土钉力设计偏于不安全或偏于保守.通过分析现行规程计算土钉力与实测土钉力的不一致性,指出现行规程计算方法存在的缺陷,进而分析研究土方开挖对土钉力的影响,讨论了基于增量法的土钉内力简化计算方法.  相似文献   

旅游地人居空间多功能研究进展与展望     

杨兴柱  殷程强 《热带地理》2022,42(5):813-823

在旅游发展快速驱动下,旅游地人居空间正处于多功能转型的关键阶段。多功能理论为旅游地人居环境可持续发展研究提供了新理论与新范式,也为中国典型地域环境下旅游地人居环境建设与调控开拓了新思路。文章系统梳理和分析了国内外关于旅游地人居空间多功能的概念演变、评估体系、变化特征、驱动机制和适应性调控等方面的研究成果,揭示已有研究的演进路径,并提出未来研究的方向和建议。主要结论包括：1）概念内涵与评估体系层面,研究视域逐渐关注高质量人居空间的多样化需求。2）空间变化特征方面,更多的研究呈现从宏观区域整体描述、中观尺度的村镇重点分析到微观住宅内部空间深入探究的空间转变。3）驱动机制层面,研究结合自然因素与社会因素2个层面来判定驱动因子。驱动力变化呈现初期“自然资源基础决定空间功能类型”,中期“产业发展引领空间功能转型”,后期“人居环境自然舒适追求”的阶段性特征。4）适应性调控层面,研究对策主要通过协调多元主体的社会关系和优化物质空间组合实现。最后,建构了旅游地人居空间多功能研究三阶段的演进路径,提出后续研究关注的重点,包括构建更全面的多功能评估指标体系、多元主体之间多功能诉求的耦合权衡机制,以及自上而下和自下而上相结合的多功能转型优化策略。研究方法方面,跨学科方法的融合与创新将成为一个重要突破。  相似文献   

行政边界对城市群交界地区土地利用变化的影响——以通州—武清—廊坊地区为例     

詹子歆  戴林琳 《地理科学进展》2022,41(12):2271-2285

由于各地资源禀赋差异和各级政府之间的复杂关系,城市群交界地区不可避免地存在经济社会发展上的矛盾和不平衡。已有研究揭示了行政边界效应在省域、城市群等不同尺度均普遍存在,且在不同阶段影响土地利用变化的程度大小不一,但多将行政边界转化为虚拟变量而非空间地理要素,不足以理解中微观尺度各种因素之间的复杂相互作用。论文旨在利用1985—2020年的中国年度土地覆盖数据集,以区县为单元,运用质心迁移、核密度分析和Logistic回归方法,分析京津冀典型城市群交界地区“通州—武清—廊坊(通武廊)地区”不透水面(ISA)的扩张机理并测度行政边界效应的影响。结果显示：① 不同行政区因资源禀赋和所处发展阶段的不同,城市用地扩张的速度和主要时期存在一定的差异;② 由于要素的高度流动,地理邻近的行政区城市扩张驱动要素表现出一定的相似性;③ 在不同区域分工水平下,行政界线的边界效应对城市用地扩张的影响表现出一定差异性。通过“强—弱”管控提高通武廊地区各要素协调水平,减少行政边界对地方之间资源整合的负面影响,对于实现京津冀城市群协同发展具有重要作用。  相似文献   

2001年1月滇黔准静止锋在演变过程中的结构及大气环流特征分析   总被引：18，自引：0，他引：18  

杜正静  丁治英  张书余 《热带气象学报》2007,23(3):284-292

利用地面常规观测资料和NCEP/NCAR再分析资料,分析2001年1月的滇黔准静止锋在演变过程中的温湿结构和大气环流特征。结果表明：滇黔准静止锋表现为湿度锋,其大气环流特征与高原关系密切。青藏高原的抬升作用与Hadley环流偏南导致Ferrel环流的生成、加强对云贵高原的天气有重大的影响。对于I、Ⅱ型静止锋,Hadley环流圈南北跨距小,环流圈下沉支偏南,易与高原南部的上升支一起形成反环流,该反环流可产生较强的雨雪、凝冻的灾害性天气;Ⅲ、IV型静止锋,Hadley环流圈北推,环流圈南北跨距大,此时在青藏高原的南部无反环流存在,云贵地区上升运动较弱,产生的降水与天气也较弱。由于受副高增强的间接影响,Hadley环流在Ⅱ、Ⅲ、IV型静止锋存在明显的双层结构。  相似文献   

The ultrastructure of separated and cultured cell of Porphyra yezoensis     

Mei Jun-xue  Fei Xiu-geng 《中国海洋湖沼学报》2001,19(1):35-39

There are many reports that cells (protoplasts) separated from the thallus ofPorphyra by enzyme can develop to normal leafy thalli in the same way as monospores. But there are few investigations on the subcellular structure of the isolated vegetative cell for comparison with the subcellular structure of monospores. To clarify whether the separated and cultured cells undergo the same or similar ultrastructure changes during culture and germination as monospores undergo in their formation and germination, we observed their ultrastructure, compared them with those of the monospore and found that the ultrastructure of separated and cultured cells did not have the characteristic feature as that of monospore formation, such as production of small and large fibrous vesicles, but was accompanied by vacuolation and starch mobilization like that in monospore germination. The paper also discusses the relations between monospores and separated and cultured cells. Contribution No. 3875 from the Institute of Oceanology, Chinese Academy of Sciences. Project 39770593 supported by NSFC; Project 96-C01-05-01 of the 9th Five-Year Plan supported by Science and Technology Commision of China.  相似文献   

SELECTION OF BRILLOUIN SHIFT DISCRIMINATOR FOR BRILLOUIN LIDAR   总被引：1，自引：0，他引：1  

吴东  刘智深 《中国海洋湖沼学报》2002,20(3):197-201

For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high-resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selected as the frequency shift discriminator and several kinds of absorption gases were tried. It was found that the strong line ( # 1095) of ^127 I2 at 18783. 3297 cm^-1 and two absorption lines of ^129 I2 located at the two sides of the # 1095 line of ^127 I2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency shift. This selection is the best one within the range from 532.0131 run to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.  相似文献   

FATTY ACIDS PROFILE IN A HIGH CELL DENSITY CULTURE OF ARACHIDONIC ACID-RICH PARIETOCHLORIS INCISA (TREBOUXIOPHYCEAE,CHLOROPHYTA) EXPOSED TO HIGH PFD     

刘建国 《中国海洋湖沼学报》2002,(2)

ＩＮＴＲＯＤＵＣＴＩＯＮＳｏｍｅω3ａｎｄω6ｌｏｎｇ ｃｈａｉｎｅｄｐｏｌｙｕｎｓａｔｕｒａｔｅｄｆａｔｔｙａｃｉｄｓ (ＰＵＦＡｓ)ｈａｖｅｂｅｅｎｒｅｃｏｇｎｉｚｅｄａｓａｎｅｓｓｅｎｔｉａｌｃｏｍｐｏｎｅｎｔｓｉｎｈｕｍａｎｎｕｔｒｉｅｎｔｓｄｕｅｔｏｔｈｅｉｒｔｈｅｒａｐｅｕｔｉｃｅｆｆｅｃｔｓａｎｄｒｏｌｅｓｉｎｍａｉｎｔａｉｎｉｎｇｃｅｌｌｍｅｍｂｒａｎｅｓｓｔｒｕｃｔｕｒｅ ,ｆｌｕｉｄｉｔｙａｎｄｆｕｎｃｔｉｏｎ .ＡｍｏｎｇｔｈｅｓｅＰＵＦＡｓ,ａｒａｃｈｉｄｏｎｉｃａｃｉｄ (ＡＡ ,2 0…  相似文献   

Effects of channel regulation on salt intrusion and residual circulation of Keelung River     

Wen‐Cheng Liu 《水文研究》2005,19(20):4039-4054

A vertical (laterally integrated) two‐dimensional numerical model was applied to study the hydrodynamic characteristics, salt‐water intrusion and residual circulation in the Danshuei River estuarine system. The cross‐sectional profiles measured in 2001 and 1990 respectively represent the conditions after and before channel regulation in the Keelung River. The model was re‐verified with the available hydrological data measured in 2001. Detailed model re‐verification has been conducted with water surface elevations, tidal current, and salinity distributions measured. The overall performance of the model is in qualitative agreement with the available field data. The model was then used to investigate the change in tidal ranges, salt‐water intrusion, and residual circulation as a result of channel regulation in the Keelung River. The model simulations indicate that more tidal energy propagates into the estuarine system before channel regulation because of the substantial increase in river cross‐sections. The residual circulations before channel regulation are greater than those after channel regulation and result in the limits of the salt intrusion before channel regulation being extended farther inland than those after channel regulation. This may show that channel regulation for flood control in the Keelung River did not contribute to the expansion of the mangrove areas and the disappearance of freshwater marshes at the Kuan‐Du wetlands. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Ultrastructure of Single Cells, Callus-like and Monospore-like Cells in Porphyra yezoensis Ueda on Semi-solid Culture Medium     

梅俊学  沈颂东  姜明  费修绠 《中国海洋湖沼学报》2003,(2)

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｓｉｎｇｌｅｃｅｌｌｓａｎｄｐｒｏｔｏｐｌａｓｔｓｏｆＰｏｒｐｈｙｒａｇａｍｅｔｏｐｈｙｔｅｂｌａｄｅｓｃｏｕｌｄｄｅｖｅｌｏｐｉｎｔｏｐｌａｎｔｌｅｔｓｄｉ ｒｅｃｔｌｙｏｒｉｎｔｏｃａｌｌｕｓ ｌｉｋｅｃｅｌｌｓ (ＺｈａｏａｎｄＺｈａｎｇ ,1 981 ;Ｐｏｌｎｅ Ｆｕｌｌｅｒｅｔａｌ.,1 984 ;Ｃｈｅｎ ,1 989;ＷａｎｇａｎｄＹａｎ ,1 990 ;Ｇａｌｌｅｔａｌ.,1 993;Ｃｈｅｎ ,1 997;ＭｅｉａｎｄＦｅｉ,2 0 0 1 ) ,ａｎｄｔｈｅｉｒｇｒｏｗｔｈａｎｄｄｅｖｅｌｏｐｍｅｎｔｕｎｄｅｒ…  相似文献