TRANSALP—A transect through a young collisional orogen: Introduction     

Helmut Gebrande  Alberto Castellarin  Ewald Lüschen  Karl Millahn  Franz Neubauer  Rinaldo Nicolich   《Tectonophysics》2006,414(1-4):1

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Expanded papers from an international workshop on performance‐based design—concepts and implementation     

Peter Fajfar  Helmut Krawinkler 《地震工程与结构动力学》2006,35(1):1-2

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The synoptic meaning of helicity   总被引：1，自引：0，他引：1  

H. Pichler  A. Schaffhauser 《Meteorology and Atmospheric Physics》1998,66(1-2):23-34

Summary Helicity, a scalar quantity resulting from the inner product of velocity and vorticity, has until now mostly been used in the field of mesoscale meteorology and boundary layer meteorology. Goals of this paper are the derivation of the flux form of the helicity equation in general form without neglection of friction and Coriolis force and the examination of helicity patterns of larger scales. The general helicity equation is approximated for the synoptic and frontal scale by use of the scale analysis. High helicity values are bounded to fronts, such that helicity determines their positions. Finally the helicity patterns at different heights and helicity sources and sinks are discussed for a case study of a cyclogenesis over the Atlantic.With 6 Figures  相似文献   

Meteorological Aspects, Ozone, and Solar Radiation Measurements During POPCORN 1994     

Theo Brauers  Hans-Peter Dorn  Helmut Koch  Annette B. Kraus  Christian Plass-Dülmer 《Journal of Atmospheric Chemistry》1998,31(1-2):33-52

Meteorological data, ozone mixing ratios, and photolysis frequencies for the period August 2 to August 24, 1994, are presented and discussed in support of the field campaign POPCORN (Photochemistry of Plant Emitted Compounds and OH Radicals in Northeastern Germany). Measurements of temperature, ozone, and wind speed at different heights are used to evaluate micro-meteorological parameters. The observations provide information about local influences on the air mass composition. The analysis of radio sonde data of nearby stations provides the height of the planetary boundary layer.  相似文献   

Investigations in the Szczecin Lagoon during the Oder Flood (July – August 1997) from a biogeochemical perspective     

Christiane Fenske  Helmut Westphal  Alexander Bachor  Elke Breitenbach  Hinrich Meyer  Wladyslaw Buchholz  Wolf-Dieter Jülich 《Ocean Dynamics》1998,50(2-3):231-243

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Frontal substructures within the planetary boundary layer   总被引：2，自引：0，他引：2  

Andreas Becker  Helmut Kraus  Cäcilia M. Ewenz 《Boundary-Layer Meteorology》1996,78(1-2):165-190

A two-dimensional mesoscale model, extended by a TKE closure for the subgrid-scale terms and coupled with a soil model, is used to investigate the role of the Planetary Boundary Layer (PBL) for the development and the substructures of two different types of cold fronts. The effects of turbulent friction, large-scale (geostrophic) forcing and the diurnal variation of the terms of the surface energy balance (SEB) equation on the frontal development are studied by 10 different model runs. The ageostrophic cross-frontal circulation in the lowest two kilometres of a cold front results from friction as well as from large-scale forcing. The first one dominates the PBL processes and causes a special boundary-layer structure, which becomes apparent through the existence of seven characteristic zones defined for the x-z cross sections of potential temperature. The arrangement of these characteristic zones depends on the sense of rotation of the frictionally induced part of the ageostrophic circulation and hence on the direction of the along-front jet within the boundary layer. The daytime increase of the terms of the SEB equation for a midlatitude midsummer case leads to a strong enhancement of the frictionally induced cross-frontal circulation. The arrangement of the seven characteristic zones, however, is approximately conserved.  相似文献   

Note in reply to Egger and Schär's comment on our article “A solenoid-mass continuity invariance criterion related to the potential vorticity conservation”     

Prog F. Herbert  Prog H. Pichler 《Meteorology and Atmospheric Physics》1996,59(3-4):259-261

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Book review     

Fernando Sansò  Helmut Moritz 《Journal of Geodesy》1989,63(2):I-II

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Shock effects in melilite     

Helmut Schäfer  Wolfgang Friedrich Müller  Ulrich Hornemann 《Physics and Chemistry of Minerals》1984,10(3):121-124

Shock recovery experiments on melilite samples in the pressure range from 11 to 50.5 GPa have been performed in order to examine the effects of shock waves on this material. The shocked samples were subsequently studied in the transmission electron microscope. All samples displayed the shock-induced amorphous areas, known as diaplectic glass. The amount of diaplectic melilite glass increased from a few percent at 11 GPa to about 85 percent at 50.5 GPa shock pressure. The shock waves also caused deformational effects as planar faults parallel to (001) and dislocations with a density in the order of 10¹⁰ cm^?2. Regarding the present discussion on the origin and nature of diaplectic glass, diaplectic melilite glass is assumed to be the reversion product of a high-density phase produced in the shock front. Deformed melilites in Ca-Al-rich inclusions from chondritic meteorites studied so far do not contain diaplectic glass. It is assumed that the meteoritic melilites were hot (>1,000° C) and thus plastically deformable by shock waves of rather low amplitudes.  相似文献   

Über den transport von Wolfram und den Absatz von Wolfram-Doppel-Oxiden in fluiden wässrigen LösungenThe transport of tungsten and the deposition of tungsten double oxides in fluid,aqueous solutions     

Helmut Schröcke  Alfons Trumm  Rupert Hochleitner 《Geochimica et cosmochimica acta》1984,48(9):1791-1805

The transportation of W in aqueous gas-phases at and above 500°C is examined using thermodynamic data. The transport of W is possible as fluoride and oxifluoride. The deposition of wolframite continues with decreasing temperature and pressure. The stabilities of wolframates in hydrothermal solutions are examined for temperatures up to 300°C with Eh-pH-diagrams, exchange reactions of wolframite with oxides, sulfides and dissolved ions. Fe₂WO₆ becomes stable against Fe₂O₃ + WO₃ above 126°C. At 300°C its range of stability begins at high pO₂ which is not realised in hydrothennal endogenous solutions. In consequence of the very low Gibbs energies of MgWO₄, CaWO₄ and BaWO₄, the minerals MgWO₄ and BaWO₄ should be more important than wolframite, if Mg and Ba coexist in solution together with W. Co and Ni also should be found as trace elements in wolframite, if Co and Ni were in solution in sufficiently high concentrations together with W.  相似文献