Some newly discovered coronal emission lines from high altitude infrared observations of the 7 March, 1970, solar eclipse     

Kenneth H. Olsen  Charles R. Anderson  John N. Stewart 《Solar physics》1971,21(2):360-371

A survey of the infrared coronal spectrum between 1 and 3 was made from a high altitude aircraft during the 7 March, 1970, solar eclipse. The observations were made with a Fourier transform spectrometer and were confined to the outer chromosphere and inner corona. In addition to well known chromospheric lines of Hi and Hei, nine additional lines were seen. Evidence is presented for the tentative assignment of these lines to forbidden transitions in highly ionized atoms of magnesium, aluminum, silicon, sulphur, and chromium.  相似文献   

COPPER-NICKEL ALLOY IN THE BLANSKO CHONDRITE     

Edward Olsen 《Meteoritics & planetary science》1973,8(3):259-261

Both Fe and Ni were measured in microprobe analyses of a large copper metal rim that formed by exsolution from a large troilite grain contained within an iron-nickel metal grain in the H-group chondrite, Blansko. The Fe content of the copper can be accounted for largely by secondary fluorescence by Cu-K_α of Fe radiation from the adjacent metal, however, fluorescence by Cu-K_β of Ni radiation cannot significantly account for the observed Ni content. Therefore, the copper actually alloys up to 2% Ni, with a concentration gradient dropping to 0.7% away from the copper-metal interface.  相似文献   

Late Holocene palaeoceanography in Van Mijenfjorden, Svalbard   总被引：2，自引：0，他引：2  

Morten Hald  Torbjörn Dahlgren  Tor-Eirik Olsen  Erland Lebesbye 《Polar research》2001,20(1):23-35

Based on detailed stratigraphical analysis of sediment cores spanning the last ca. 4000 calendar years, we reconstruct the palaeoceanograhic changes in the fiord Van Mijenfjorden, western Svalbard. Benthic foraminiferal δ¹⁸O indicate a gradual reduction in bottom water salinities between 2200 BC and 500 BC. This reduction was probably mainly a function of reduced inflow of oceanic water to the fiord, due to isostatic shallowing of the outer fiord sill. Stable salinity conditions prevailed between 500 BC and. 1300 AD. After the onset of a major glacial surge of the tidewater Paulabreen (Paula Glacier) system (PGS) around 1300 AD, there was a foraminiferal faunal change towards glacier proximal conditions, associated with a slight bottom water salinity depletion. During a series of glacial surges occuring from 1300 AD up the present salinity in the fiord has further decreased, corresponding to a δ¹⁸O depletion of 0.5 %o. This salinity decrease corresponds to the period when the PGS lost an equivalent of 30 – 40 % of its present ice volume, mainly through calving in the fiord.  相似文献   

Differing susceptibility of anadromous brown trout (Salmo trutta L.) populations to salmon louse (Lepeophtheirus salmonis (Kroyer, 1837)) infection     

Glover  K.A; Skaala  O; Nilsen  F; Olsen  R; Teale  A.J; Taggart  J.B 《ICES Journal of Marine Science》2003,60(5):1139-1148

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Stage-specific habitats of Calanus finmarchicus and Calanus helgolandicus in a stratified northern Norwegian fjord     

Skreslet  S.; Olsen  K.; Mohus  A.; Tande  K. S. 《ICES Journal of Marine Science》2000,57(6):1656-1663

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Seasonal and interannual variability of the air–sea CO₂ flux in the Atlantic sector of the Barents Sea     

Abdirahman M. Omar  Truls Johannessen  Are Olsen  Staffan Kaltin  Francisco Rey 《Marine Chemistry》2007,104(3-4):203-213

The seasonal and interannual variability of the air–sea CO₂ flux (F) in the Atlantic sector of the Barents Sea have been investigated. Data for seawater fugacity of CO₂ (fCO₂^sw) acquired during five cruises in the region were used to identify and validate an empirical procedure to compute fCO₂^sw from phosphate (PO₄), seawater temperature (T), and salinity (S). This procedure was then applied to time series data of T, S, and PO₄ collected in the Barents Sea Opening during the period 1990–1999, and the resulting fCO₂^sw estimates were combined with data for the atmospheric mole fraction of CO₂, sea level pressure, and wind speed to evaluate F.The results show that the Atlantic sector of the Barents Sea is an annual sink of atmospheric CO₂. The monthly mean uptake increases nearly monotonically from 0.101 mol C m^− 2 in midwinter to 0.656 mol C m^− 2 in midfall before it gradually decreases to the winter value. Interannual variability in the monthly mean flux was evaluated for the winter, summer, and fall seasons and was found to be ± 0.071 mol C m^− 2 month^− 1. The variability is controlled mainly through combined variation of fCO₂^sw and wind speed. The annual mean uptake of atmospheric CO₂ in the region was estimated to 4.27 ± 0.68 mol C m^− 2.  相似文献   

Modelling free-forming meander evolution in a laboratory channel using three-dimensional computational fluid dynamics   总被引：1，自引：0，他引：1  

N. Rüther  N.R.B. Olsen 《Geomorphology》2007,89(3-4):308-319

The present study investigated the use of computational fluid dynamics (CFD) in predicting the formation, development, and migration of free-forming meander bends. The three-dimensional CFD model computed water flow and sediment transport in alluvial channels and predicted vertical and horizontal bed changes. Different algorithms and parameters were tested to provide an insight into the application range of CFD when modelling free-forming meander formation. The computational domain was discretized by an unstructured grid. A control volume method was used for the discretization of the Navier–Stokes equations for the flow calculation and of the convection–diffusion equation for the sediment transport calculation. Turbulence was modelled by the k–ε turbulence model. The simulation was started from an initially straight grid, with neither sediment feed nor any perturbation at the inflow boundary. The model computed the river bed evolution over a real time period of 3 d. Results were compared with laboratory experiments and showed that the CFD model can predict many of the characteristics of the alluvial meander formation and migration. However, some limitations and uncertainties exist that have to be clarified in future investigations.  相似文献   

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

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Spatial Transgression and the BYU Jerusalem Center Controversy*     

Daniel H. Olsen  Jeanne Kay Guelke 《The Professional geographer》2004,56(4):503-515

Dominant groups tend to construct the meaning of places to justify and sustain their ideology and orthodoxy in order to solidify power and to maintain their control over others. New outsider groups whose ideology disrupts the established order and sovereignty of the dominant group can be labeled transgressive ( Sibley 1995; Cresswell 1996 ). Transgressions of hegemonic spaces force dominant groups to reexamine themselves and to reaffirm or to modify their position. This concept of transgression is used to examine the controversy surrounding the building of the Brigham Young University Jerusalem Center in the mid‐1980s in Jerusalem. The public outcry among some Israelis over the building of this educational edifice concerned the potential use of the Jerusalem Center as a focal point for Mormon (Latter‐day Saints) proselytizing efforts. We examine the way the Jerusalem Center was viewed and depicted by its opponents, suggesting how basic geographic concepts such as scale and site further refine the concept of spatial transgression for buildings and urban redevelopment.  相似文献   

Grinding circuit parameter estimation using the maximum likelihood method     

Thor O. Olsen  Thore Lenhartzen 《International Journal of Mineral Processing》1979,6(2):133-153

After a summary of maximum likelihood (ML) estimation, the application of the ML-method is demonstrated by estimating parameters in a ball mill-hydrocyclone grinding circuit from flow and density measurements. The model with the estimated parameters is used to determine the time propagation of mill contents and size distribution.  相似文献