X-ray emission as a tracer of circumstellar matter around herbig ae/be stars     

Hans Zinnecker  Thomas Preibisch 《Astrophysics and Space Science》1995,224(1-2):587-588

We have detected X-ray emission (1 keV) from young intermediate-mass stars (Herbig Ae/Be stars). Since these stars are not supposed to produce intrinsic X-ray emission (no convection, no coronae), we believe that our results suggest that the X-ray emission actually traces the shock interaction of the Ae/Be star stellar winds with remnant circumstellar matter left over from the star formation process, the presence of which is also indicated by far-infrared (IRAS) and submm/mm continuum data.  相似文献   

Approximation functions to the emden and associated emden functions near the first zero,II     

Albert P. Linnell 《Astrophysics and Space Science》1977,47(1):253-253

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4398361 Recovery of sediments from the bottom of the sea by suspended suction pipe     

Hans Amann  Jurge Burkhardt 《Marine pollution bulletin》1984,15(3):122

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A magnitude scale for very large earthquakes   总被引：7，自引：0，他引：7  

George Purcaru  Hans Berckhemer 《Tectonophysics》1978,49(3-4)

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Editorial     

Hans Hecklau 《GeoJournal》1978,2(4):288-288

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UBV photometry at geographic latitude 69°22′ North     

Hans KR. Myrabø 《Astrophysics and Space Science》1979,60(2):367-374

UBV measurements of the light of the night sky in the auroral zone during three seasons are presented. The mean brightness of the night sky in theV band is found to be equal one 18^m1 star (arc sec)^–2, with considerable variations. The observed meanB-V andU-B indicies are +0 _. ^m 7 and –1 _. ^m 6, respectively.Light curves of variable stars during strong auroral activities are also shown. On the basis of measurements we briefly discuss the possibility of accurate stellar photometry in the auroral region.  相似文献   

Benthonic foraminifera as indicators of the paleoposition of the Subarctic Convergence in the Norwegian-Greenland Sea     

Hans-Petter Sejrup  Hans Holtedahl  Olav Norvik  Ivar Miljeteig 《Boreas: An International Journal of Quaternary Research》1980,9(3):203-207

A method is presented for correlating benthonic foraminiferal communities in Late Quaternary marine sediments on continental shelves and in coastal areas with the planktonic foraminiferal stratigraphy of the North Atlantic and Norwegian Sea deep-sea sediments.  相似文献   

The general equilibria of a spinning satellite in a circular orbit     

Hans J. Sperling 《Celestial Mechanics and Dynamical Astronomy》1972,6(3):278-293

Let a rigid satellite move in a circular orbit about a spherically symmetric central body, taking into account only the main term of the gravitational torque. We shall investigate and find all solutions of the following problem: Let the satellite be permitted to spin about an axis that is fixed in the orbit frame; the satellite need not be symmetric, the spin not uniform, and the spin axis not a principal axis of inertia. The complete discussion of this type of spin reveals that the cases found by Lagrange and by Pringle - and the well-known spin about a principal axis of inertia orthogonal to the orbit plane — are essentially the only ones possible; the only further (degenerate) case is uniform spin of a two-dimensional, not necessarily symmetric satellite about certain axes that are orthogonal to the plane containing the body and to the orbit of the satellite around the central body.  相似文献   

MORICE--new technology for mechanical oil recovery in ice infested waters     

Jensen HV  Mullin JV 《Marine pollution bulletin》2003,47(9-12):453-469

Mechanical oil recovery in ice infested waters (MORICE) was initiated in 1995 to develop technology for the recovery of oil spills in ice. It has been a multinational effort involving Norwegian, Canadian, American and German organizations and researchers. Through a stepwise approach with the development organized in six separate phases, laboratory tests and field experiments have been conducted to study various ideas and concepts, and to refine the ideas that were considered to have the best potential for removing oil in ice. Put together in one unit, these concepts included ice processing equipment and two alternative oil recovery units installed on a work platform. In January 2002, the final oil and ice testing with MORICE concepts was conducted at the Ohmsett test facility in Leonardo, New Jersey. The unit has been referred to as a harbor version to indicate the size and operating conditions, but the concepts could be scaled up to increase the capacity of oil and ice processing. For heavier ice conditions it would also be necessary to increase the overall strength.  相似文献   

A depositional model for the terminal Neoproterozoic–Early Cambrian Ara Group evaporites in south Oman     

Stefan Schröder  B. Charlotte Schreiber†  Joachim E. Amthor‡  Albert Matter 《Sedimentology》2003,50(5):879-898

Abstract Six evaporite–carbonate sequences are recognized in the terminal Neoproterozoic–Early Cambrian Ara Group in the subsurface of Oman. Individual sequences consist of a lower, evaporitic part that formed mainly during a lowstand systems tract. Overlying platform carbonates contain minor amounts of evaporites and represent transgressive and highstand systems tracts. Detailed sedimentological and geochemical investigation of the evaporites allowed reconstruction of the depositional environment, source of brines and basin evolution. At the beginning of the evaporative phase (prograding succession), a shallow-water carbonate ramp gradually evolved into a series of shallow sulphate and halite salinas. Minor amounts of highly soluble salts locally record the last stage of basin desiccation. This gradual increase in salinity contrasts sharply with the ensuing retrograding succession in which two corrosion surfaces separate shallow-water halite from shallow-water sulphate, and shallow-water sulphate from relatively deeper water carbonate respectively. These surfaces record repeated flooding of the basin, dissolution of evaporites and stepwise reduction in salinity. Final flooding led to submergence of the basin and the establishment of an open-water carbonate ramp. Marine fossils in carbonates and bromine geochemistry of halite indicate a dominantly marine origin for the brines. The Ara Group sequences represent a time of relatively stable arid climate in a tectonically active basin. Strong subsidence allowed accommodation of evaporites with a cumulative thickness of several kilometres, while tectonic barriers simultaneously provided the required restricted conditions. Subsidence allowed evaporites to blanket basinal and platform areas. The study suggests a deep-basin/shallow-water model for the evaporites.  相似文献