LOCAL SCOUR ESTIMATION AT BRIDGE SITE: MODIFICATION AND APPLICATION OF LACEY FORMULA   总被引：1，自引：0，他引：1  

Md. Munsur RAHMAN  iwfm.buet.ac.bd  at present: Post Doctoral Research fellow  Ujigawa Open Laboratory  Disaster Prevention Research Institute  Kyoto University  Shimomisu  Yoko-Oji  Fushimi-Ku  Kyoto -  Japan  M. Anisul HAQUE 《国际泥沙研究》2003,18(4)

In the recent years, it has been established that b/h or h/b (b = length of the structure in the lateral direction and h = approach flow depth) is the dominant factor for the estimation of local scour depth around abutments and piers. One of the major limitations of the Lacey formula is that it predicts only one value of the scour depth for a specific river because of the absence of important parameters b and h. Therefore, its application is quite uncertain for variable b and h. Considering its limitations and experimental facts of flow concentration and shear stress amplification close to above structures, the original Lacey formula is modified introducing the parameters b and h. The applicability of the original as well as modified Lacey formula is tested to the data collected from major rivers in Bangladesh.  相似文献   

Conodonts from the Upper Cambrian Sesong and Hwajeol Formations in the Sabuk Area, South Korea     

LEE Byung-SuDepartment of Earth Science Education  Chonbuk National University  Jeonju  -  Korea Zhu Xiling 《《地质学报》英文版》2002,76(2):155-165

This paper presents a conodont biostratigraphic study on the Upper Cambrian Sesong and Hwajeol Formations in the Sabuk area, Korea. Two samples near the base of the Sesong Slate at the Pukil section contain lower Upper Cambrian conodonts, comprising Furnishina furnishi, F. kranzae, F. pernical, F. triangulate, Hertzina elongata, Laiwugnathus doidyxus?, Phakelodus elongatus, Muellerodus? obliquus, Westergaardodina matsushitai and W. moessebergensis. This is the first conodont record of the Upper Cambrian formations recovered yet in the northern limb of the Paekunsan syncline. The faunal assemblage is correctable with the lower Upper Cambrian W. matsushitai Zone of North China. Four local biozones are recognized in the Hwajeol Formation, i.e. the Proconodontus, Eoconodontus notchpeakensis, Cambrooistodus minutus and Cordylodus proavus Zones in ascending order. This zonal scheme is essentially equivalent to that of the southern limb of the Paekunsan syncline and they are correlatable with zones in other pa  相似文献   

WISE EXPLOITATION OF NEWLY GROWING LAND RESOURCES——An Assessment on Land-use Change of Chongming Island Using GIS   总被引：2，自引：0，他引：2  

ZHAO Bin    LI Bo  MA Zhi-jun  CHEN Jia-kuan  NAKAGOSHI Nobukazu 《中国地理科学(英文版)》2003,(2)

1INTRODUCTIONThreewell-documentedmajorglobalchangesaffectinghumanbeingsareincreasingconcentrationofcarbondioxideintheatmosphere,alterationinthebiochemistryoftheglobalnitrogencycle,andon-goinglanduse/coverchange(LUCC)(VITOUSEK,1994).Forcen-turies,humanbeingshavebeenalteringtheearth'ssurfacetoproducetheirfoodandsheltersthroughagri-culturalactivities(REIDetal.,2000).Likeothercountries,Chinaisalsosubjecttolandtransformation,forinstance,abouthalfamillionhectaresofwetlandshavebeenreclaime…  相似文献   

辛勤耕耘,成果卓著——深切怀念涂光炽先生     

中国科学院地球化学研究所矿床地球化学国家重点实验室 《矿物学报》2007,27(Z1):1-2

涂光炽院士是我国地球化学事业的奠基者,国内外著名的矿床学家和地球化学家.他从事地球科学研究60多年来,先后考察和研究了国内外400多个矿床,提出了一系列符合地质实际的新思想、新理论和新观点,出版专著23部,发表论文250余篇,获得了包括国家自然科学一、二等奖在内的重要学术奖励20余项.这些研究成果丰富和发展了矿床学、地球化学的理论体系,对矿产资源的寻找具有重要指导作用.  相似文献   

Characterizing the dynamics of soil organic carbon in grasslands on the Qinghai-Tibetan Plateau   总被引：4，自引：0，他引：4  

ZHANG YongQiang    TANG YanHong  JIANG Jie & YANG YongHui Environmental Biology Division  National Institute for Environmental Studies  - Tsukuba  Japan  Institute of Geographic Sciences  Natural Resources Research  Chinese Academy of Sciences  Beijing  China  Research Center for Agricultural Resources  Institute of Genetics  Develepmental Biology Chinese Academy of Sciences  Shijiazhuang  China 《中国科学D辑(英文版)》2007,50(1):113-120

Carbon dynamics of grasslands on the Qinghai-Tibetan Plateau may play an important role in regional and global carbon cycles. The CENTURY model (Version 4.5) is used to examine temporal and spatial variations of soil organic carbon (SOC) in grasslands on the Plateau for the period from 1960 to 2002. The model successfully simulates the dynamics of aboveground carbon and soil surface SOC at the soil depth of 0-20 cm and the simulated results agree well to the measurements. Examination of SOC for eight typical grasslands shows different patterns of temporal variation in different ecosystems in 1960-2002. The extent of temporal variation increases with the increase of SOC of ecosystem. SOC increases first and decreases quickly then during the period from 1990 to 2000. Spatially, SOC density obtained for the equilibrium condition declines gradually from the southeast to the northwest on the plateau and showed a high heterogeneity in the eastern plateau. The results suggest that (i) SOC den-sity in the alpine grasslands shows remarkable response to climate change during the 42 years, and (ii) the net carbon exchange rate between the alpine grassland ecosystems and the atmosphere increases from 1990 to 2000 as compared with that before 1990.  相似文献   

以林带为例说明统计方法在分析自然界相互关系的应用     

Г.В.阿尔曼德-特卡钦科  叶蒸 《地理学报(英文版)》1958,(1)

大家知道,自1949年到1952年曾规模宏大地进行了营造农田防护林的工作。这些工作的结果远不是到处都是成功的。但是如果对这一时期的工作进行缜密的研究并对于将来作出推断,那么,不论是成功的或失败的经验都将是有用的。但直到现在为止,这样的研究工作还没有足够的规模来进行。那些取决於林带的配置和栽植方法,特别是取决  相似文献   

以林带为例说明统计方法在分析自然界相互关系的应用     

Г.В.阿尔曼德-特卡钦科  叶蒸 《地理学报》1958,(1)

大家知道,自1949年到1952年曾规模宏大地进行了营造农田防护林的工作。这些工作的结果远不是到处都是成功的。但是如果对这一时期的工作进行缜密的研究并对于将来作出推断,那么,不论是成功的或失败的经验都将是有用的。但直到现在为止,这样的研究工作还没有足够的规模来进行。那些取决於林带的配置和栽植方法,特别是取决  相似文献   

Studying Air Pollution with Kitt Peak Solar Flux Atlas—Analysis Method and Results of Observation     

Jianguo Niu  Hiroaki Kuze  Nobuo Takeuchi 《大气科学进展》2000,(3)

l.Introducti0nTwoflightsoftheSAGEIIIinstrumentwereplanedbeinglaunchedinJune2O00byRussianMeteor-3Mandin2002byInternationalSpaceStation(ISS).Itisexpectedthattheywouldofferinformationofalmostglobalcoverage.Theseinstrumentswillutilizetheselfcal-ibratingsolaroccultationtechniquetomeasureprofilesofaerosoIextinctionfrom0to4Okm,ozonefrom6to85km,nitrogendioxidefroml0to5Okm,andwatervaporfrom0to5Okm,andutilizelunaroccultationobservati0nstomonitorthekeynighttimesPecies,nitrogentrioxidefrom22to55k…  相似文献   

黑龙江省气象环境综合治理代表团访昌考察报告     

黑龙江省气象环境综合治理代表团 《黑龙江气象》2000,(3):46-48

为了解日本在气象环境综合治理方面的情况,在中国气象局国际合作部的大力支持下,与北海道科学技术交流协会联系并经省政府批准,以黑龙江省气象局副局长贾世民为团长的黑龙江省气象环境综合治理代表团一行8人,于1999年10月4日至15日对日本进行了考察访问.  相似文献   

本刊加入万方数据资源系统(ChinaInfo)数字化期刊群的声明     

《气候与环境研究》编辑部 《气候与环境研究》2000,5(3):295-295

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