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排序方式: 共有230条查询结果,搜索用时 15 毫秒
191.
192.
Peter Ergenzinger Carmen de Jong Berlin Environmental Research Group Institut fur Geographische Wissenschaften Freie Universitut Berlin Grunewaldstr. Berlin Germany 《国际泥沙研究》1997,(3)
LIN~DUCTIONTheinvenigationsofrivermorphologyandOfriverbeddebilityresultalwaysinidalsabouttheinterrelationshipbetweenthehydrauliccondihons,sc(hant~rtandbeddynndcs.ThedeCOuragingfactforsuchinveedgationsarethecomplexityoftheseSystemsandthehugenumberofimportantvariables.IfwefollowSimonsetal(1965)andall~eneeandtheconcentrationsofSUSPendedlOadandbedloadthefollowingparametersarethepnncapleVarialllesf-av~velocityofnow,diStributionofnowvelociticsacdeadofturbulence-meandepthacthedistributionofde… 相似文献
193.
STABILITY ANALYSIS OF COFFERDAM SLUMP AND ITS APPLICATION IN THE CLOSURE OPERATION OF THREE GORGES PROJECT 总被引:1,自引:0,他引:1
WANG Guangqian Professor Dept. of Hydraulic Engineering Tsinghua University Beijing China ZHOU Hougui Senior Engineer Gezhouba Group Corporation Yichang Hubei China LIU Lubo Master Student Dept. of Hydraulic Engineering Tsinghu 《国际泥沙研究》1997,(3)
I.INTRODUCTIONTheclosureoperationofThreeGorgesprojectisfamousintheworldforitslargedischarge,deepwater,lowvelocityinclosuregaps,largequantitiesandhighintensityforfillingmaterials.Thus,thedikeconstT'Uctionintheclosureoperationprocessisverydifficult.Sothedesign,researchandconstrUctiongroupshavepaidmuchenergyinthedesignprinciplesandoptimalitymeasuresofthegrandriverclosureoperation.FromtheexperimentsofhydraulicsanddikeslumpinthesecondperiodofclosureoperationattheResearchinstitUteofYangtZeR… 相似文献
194.
The Radioheliograph Group 《Solar physics》1989,120(1):193-204
A multi-frequency capability has been added to the north-south array of the Nançay Radioheliograph, providing observations at up to five frequencies between 150 and 450 MHz with time resolution 0.1 s. The projected position, brightness and dimension of sources in the solar corona can thus be studied as a function of height. Two-dimensional information is obtained at 164 MHz using the east-west and north-south arrays. In addition, the quiescent corona can be mapped in two dimensions at all observed frequencies by earth rotation synthesis. The paper describes the new aspects of the antennae, the receiver frontend, the data acquisition and the calibration procedure. The performances of the instrument are illustrated with multi-frequency observations of solar fast-drift bursts, continuum emission and maps of the quiet corona.Meudon: Y. Avignon, J. Bonmartin, A. Bouteille, B. Clavelier, E. Hulot, M. P. Issartel, A. Kerdraon, K.-L. Klein, P. Lantos, C. Mercier, M. Pick, A. Raoult, D. Rigaud, G. Trottet, N. Vilmer. Nançay: C. Chantelat, M. Chapuis, Y. Chapuis, A. Coffre, C. Couteret, B. Darchy, P. Guéniau, D. Lalardie, P. Picard, R. Tocqueville. 相似文献
195.
"现代地球磁场监测与地磁基本数据积累"项目成果介绍 总被引:1,自引:0,他引:1
"现代地球磁场监测与地磁基本数据积累"项目组 《国际地震动态》2006,(9):73-77
本文详细介绍了“现代地球磁场监测与地磁基本数据积累”项目的立项背景、目标、所开展的主要工作、取得的成果、研究成果的社会效益和对该领域研究未来工作的展望。 相似文献
196.
197.
Mick Healey Pauline Kneale John Bradbeer with other members of the INLT Learning Styles Concepts Group 《Area》2005,37(1):30-42
Growing diversity is focusing attention on the range of different student learning styles. This study assesses whether geographers have a predominant learning style and whether this varies between and within countries. The findings are based on over 900 geography students from 12 universities in Australia, New Zealand, the UK and the US, who completed Kolb's Learning Style Inventory (LSI). The implications for curriculum design and student learning strategies are discussed. It is suggested that departments should aim to produce balanced learners with a full range of learning capacities rather than simply matching teaching to existing learning styles. 相似文献
198.
Ewald Lüschen Bernd Lammerer Helmut Gebrande Karl Millahn Rinaldo Nicolich TRANSALP Working Group 《Tectonophysics》2004,388(1-4):85
The TRANSALP Group, comprising of partner institutions from Italy, Austria and Germany, acquired data on a 340 km long deep seismic reflection line crossing the Eastern Alps between Munich and Venice. Although the field work was split into four campaigns, between fall 1998 and summer 2001, the project gathered for the first time a continuous profile across the Alps using consistent field acquisition and data processing parameters. These sections span the orogen itself, at its broadest width, as well as the editor Fred Davey and the two adjacent basins. Vibroseis and explosion data, complementary in their depth penetration and resolution characteristics, were obtained along with wide-angle and teleseismic data. The profile shows a bi-vergent asymmetric structure of the crust beneath the Alpine axis which reaches a maximum thickness of 55 km, and 80–100 km long transcrustal ramps, the southward dipping ‘Sub-Tauern-Ramp’ and the northward-dipping ‘Sub-Dolomites-Ramp’. Strongly reflective patterns of these ramps can be traced towards the north to the Inn Valley and towards the south to the Valsugana thrust belt, both of which show enhanced seismicity in the brittle upper crust. The seismic sections do not reveal any direct evidence for the presence of the Periadriatic Fault system, the presumed equivalent to the Insubric Line in the Western Alps. According to our new evolutionary model, the Sub-Tauern-Ramp is linked at depth with remnants of the subducted Penninic Ocean. The ‘crocodile’-type model describes an upper/lower crustal decoupling and wedging of both the European and the Adriatic–African continents. 相似文献
199.
The 9th-Generation International Geomagnetic Reference Field 总被引:5,自引:0,他引:5
International Association of Geomagnetism Aeronomy Division V Working Group Participating members: S. Macmillan S. Maus T. Bondar A. Chambodut V. Golovkov R. Holme B. Langlais V. Lesur F. Lowes H. Lühr W. Mai M. Mandea N. Olsen M. Rother T. Sabaka A. Thomson I. Wardinski 《Geophysical Journal International》2003,155(3):1051-1056
200.
安庆夕卡岩型铁铜矿床地质地球化学特征及铁质来源研究 总被引:9,自引:1,他引:9
束学福 《矿物岩石地球化学通报》2004,23(3):219-224
安庆夕卡岩型铁铜矿床是长江中下游地区铜、铁成矿带的一个重要组成部分,其成岩成矿特征与典型的夕卡岩矿床有明显差别。本文通过对与成矿密切相关的月山岩体的岩石学和地球化学研究,以及夕卡岩分带特征与夕卡岩矿物学研究,指出岩体具高碱低铁的特征,夕卡岩矿物(石榴子石和透辉石)具富铁的特征,并有明显的逆向分带规律。并据此提出了铁质来源与磁铁矿的成矿作用的新观点,指出Fe质源自于形成岩体的富钠高铁的玄武岩浆;由于AFC作用,使FeNa分离,形成了富铁的成矿流体。而夕卡岩矿物的逆向分带和富铁夕卡岩矿物的广泛存在则是富铁流体参与夕卡岩成岩作用的结果。 相似文献