Editorial Appreciation     

Oddbjørn Engvold  Jack Harvey  John Leibacher  Takashi Sakurai  Zdeněk Švestka  Lidia van Driel-Gesztelyi 《Solar physics》2006,233(1):1-2

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A focal plane detector design for a wide-band Laue-lens telescope     

Ezio Caroli  Natalia Auricchio  Lorenzo Amati  Yuriy Bezsmolnyy  Carl Budtz-JøRgensen  Rui M. Curado da Silva  Filippo Frontera  Alessandro Pisa  Stefano Del Sordo  John B. Stephen  Giulio Ventura 《Experimental Astronomy》2005,20(1-3):341-351

The energy range above 60 keV is important for the study of many open problems in high energy astrophysics such as the role of Inverse Compton with respect to synchrotron or thermal processes in GRBs, non thermal mechanisms in SNR, the study of the high energy cut-offs in AGN spectra, and the detection of nuclear and annihilation lines. Recently the development of high energy Laue lenses with broad energy bandpasses from 60 to 600keV have been proposed for a Hard X ray focusing Telescope (HAXTEL) in order to study the X-ray continuum of celestial sources. The required focal plane detector should have high detection efficiency over the entire operative range, a spatial resolution of about 1mm, an energy resolution of a few keV at 500keV and a sensitivity to linear polarization. We describe a possible configuration of the focal plane detector based on several CdTe/CZT pixelated layers stacked together to achieve the required detection efficiency at high energy. Each layer can operate both as a separate position sensitive detector and polarimeter or work with other layers to increase the overall photopeak efficiency. Each layer has a hexagonal shape in order to minimize the detector surface required to cover the lens field of view. The pixels would have the same geometry so as to provide the best coupling with the lens point spread function and to increase the symmetry for polarimetric studies.  相似文献   

ISO-SWS Spectra of Carbon Stars: Molecular Features and a Comparison with Models     

J. Hron  R. Loidl  F. Kerschbaum  U.G. Jørgensen 《Astrophysics and Space Science》1997,255(1-2):359-360

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Survival,growth and shell deformities of copper- and cadmium-exposed mussels (Mytilus edulis L.) in brackish water     

Inke Sunila  Reijo Lindström 《Estuarine, Coastal and Shelf Science》1985,21(4):555-565

Mussels, Mytilus edulis L., were exposed to elevated concentrations of copper or cadmium in the laboratory, then placed in cages in the sea (salinity 7‰). One year later maximum lengths of the mussels were measured and shells screened for deformities. Growth was 0·6 cm year^?1 in the control cages and retarded in cages of exposed mussels. A total of 63% of cadmium-exposed and 46% of copper-exposed mussels had shell deformities. In the control cages 26% were deformed while in a natural population only 3% were deformed. The proportion of deformities to growth was inversely related. Low concentrations showed their injuriousness in this long-term test, probably due to the closing of the valves during exposure to high concentrations.  相似文献   

Basic phase relations of polybaric batch, percolative and critical melting     

S. Maaløe 《Mineralogy and Petrology》2003,77(1-2):1-24

Summary ?Partial melting of the mantle is polybaric which implies that the phase relations change during partial melting. In addition to the pressure the composition of the melt depends on the melting mode. Various melting models have been suggested. Here the basic phase relations of polybaric batch, percolative, and critical melting are considered, using a simple ternary system. The percolative melts are in equilibrium with their residua, but differ somewhat in composition from those of batch melting. Critical melting is a fractional type of melting where the residuum contain interstitial melt. The critical melts differ in composition from batch melts. The linear trends of peridotites from ophiolites show that the extracted melts had nearly constant compositions, and therefore were extracted within a small pressure interval. A comparison between the trends of mantle peridotite and experimental batch melts suggests strongly that the melt extracted from the peridotites are in equilibrium with their residua. This could suggest that either batch or percolative melting are relevant melting modes for the mantle. However, isotopic disequilibria favor instead a critical mode of melting. This inconsistency can be avoided if the ascending melts are accumulated within a source region and equilibrate with the residuum before the melt is extracted from the source region. The evidence for equilibrium suggests that multisaturation of tholeiitic compositions in PT-diagrams is relevant for estimating pressure and temperature of generation of primary tholeiitic magmas. Received September 2, 2001; revised version accepted March 20, 2002  相似文献   

The palaeoenvironment associated with a partial Iguanodon skeleton from the Upper Weald Clay (Barremian, Early Cretaceous) at Smokejacks Brickworks (Ockley, Surrey, UK), based on palynomorphs and ostracods     

Eleanor Nye  Susanne Feist-Burkhardt  David J. Horne  Andrew J. Ross  John E. Whittaker 《Cretaceous Research》2008,29(3):417-444

In 2001 a partial skeleton of an Iguanodon was discovered in the Upper Weald Clay (Barremian, Early Cretaceous) at Smokejacks Brickworks near Ockley, Surrey, UK. When the dinosaur was excavated, a detailed stratigraphic section was logged and 25 samples taken for palynological and micropalaeontological (ostracod and megaspore) analysis, including a detailed sample set of the dinosaur bed itself. Qualitative and quantitative analysis of the palynoflora revealed rich and well-preserved non-marine assemblages of pollen and spores, including early angiosperms, and freshwater green algae. Four types of angiosperm pollen are described and assigned to the genus Retimonocolpites Pierce, 1961, but left in open nomenclature. Some marine elements such as dinoflagellate cysts are identified as the result of reworking of Middle and Upper Jurassic sediments. The pollen/spore assemblages depict a vegetational change from principally gymnosperm-dominated assemblages at the base to principally pteridophyte-dominated assemblages at the top of the section. The dinosaur bed shows a pteridophyte-dominated assemblage, with a significantly high amount of the freshwater green alga Scenedesmus novilunaris He Cheng-quan et al., 1992. Samples close to the dinosaur bed yielded the first useful ostracod finds from Smokejacks Brickworks: well-preserved assemblages containing Cypridea clavata (Anderson, 1939), Damonella cf. pygmaea (Anderson, 1941), Stenestroemia cf. cressida Anderson, 1971 and Stenestroemia sp. A, and fragments and damaged valves of a thin-shelled ostracod, possibly belonging to Mantelliana Anderson, 1966. Those identified as Cypridea clavata show a wide range of morphological variety and in opposition to Anderson's (1967, 1985) taxonomic scheme, which would assign them to up to five different taxa, they are considered to be intraspecific variants of a single species. The possibilities and limitations of age determination of the Wealden sediments using palynomorphs and ostracods are discussed; distinct forms of early angiosperm pollen, together with the ostracod fauna, are consistent with an early Barremian age. Pollen and spores are discussed in terms of their parent plants and the reconstruction of vegetation and palaeoclimate. Palynology and ostracods give evidence for temporary freshwater conditions at the time when the Iguanodon died and the carcase was buried.  相似文献   

Palynofacies and sea-level changes in the Upper Cretaceous of the Vocontian Basin, southeast France     

Annette E. Gtz  Susanne Feist-Burkhardt  Katrin Ruckwied 《Cretaceous Research》2008,29(5-6):1047

Upper Cretaceous platform carbonates of the Vocontian Basin (southeastern France) have been investigated in a cross-section from the proximal deposits exposed in the lower Rhône Valley to the distal part of the basin in the Southern Subalpine Ranges north of Nice. The stratigraphic interval studied in detail spans the uppermost Turonian and Coniacian.Palynofacies patterns were used to detect eustatic signals at a third-order scale and are the tool for correlation of proximal and distal platform deposits. The organic constituents observed in the studied samples have been grouped into a continental fraction, including higher plant debris (phytoclasts) and sporomorphs, and a marine fraction with dinoflagellate cysts, acritarchs, prasinophytes, and foraminiferal test linings. The main factors influencing the stratigraphic and spatial distribution of land-derived, allochthonous, and marine, relatively autochthonous, organic particles are the proximity of land, the organic productivity, the degree of biodegradation and the hydrodynamic conditions of the depositional system. Palynofacies parameters used for the sequence stratigraphic interpretation are: (1) the ratio of continental to marine constituents (CONT/MAR ratio); (2) the ratio of opaque to translucent phytoclasts (OP/TR ratio); (3) the phytoclast particle size and shape; and (4) the relative proportion and species diversity of marine plankton. Ternary diagrams illustrating significant proximality changes were used to decipher transgressive-regressive trends within the succession.High amounts of translucent phytoclasts and decreasing values of the CONT/MAR ratio occur during the phase of relative sea-level rise in the upper Turonian. The stratigraphic interval of maximum flooding around the Turonian/Coniacian boundary is marked by the highest abundance and species diversity of dinoflagellate cysts, and by high percentages of opaque, equidimensional particles within the phytoclast group. The OP/TR ratio is still high within the lower Coniacian representing the early highstand deposits, whereas the relative abundance of marine constituents is again decreasing. Sedimentary organic matter of the upper Coniacian is dominated by large, blade-shaped, mainly opaque phytoclasts, which are a characteristic palynofacies signature of late highstand deposits.The present study demonstrates the high potential of palynofacies analysis in high-resolution stratigraphy and correlation of sedimentary series of shallow epeiric seas.  相似文献   

Site descriptive modelling during characterization for a geological repository for nuclear waste in Sweden     

A. Ström  J. Andersson  K. Skagius  A. Winberg 《Applied Geochemistry》2008

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The Nordic geological surveys： Geology for society in practice   总被引：1，自引：0，他引：1  

Morten Smelror Andreas AhlstrФm Lena Ekelund Jens Morten Hansen Keijo Nenonen Anette K. Mortensen 《《幕》》2008,31(1):193-200

Since the mid-nineteenth century., when the first of the Nordic Geological Surveys were established, they have generated a substantial amount of information on the Earth＇s crust, its natural resources, its processes, and on the geological history of Nordic areas. The collective mission of the geological surveys is to carry out ＂Geology for Society＂, by doing research and providing services, and by making geological information and data easily accessible to all the varied end users in industry, government agencies, government institutes, public administrations, technical offices, academia and research institutes, as well as for private individuals. The present paper gives a brief overview of a few, selected, research areas and projects currently undertaken by the Nordic geological surveys. These serve as practical examples of how the Nordic geological surveys address important societal problems and challenges that require geological input for their solution.  相似文献   

The cellular distribution of glutathione S-transferase in plaice: An immunocytochemical study     

Tracy Gallagher  Andras Strm  Stephen George 《Marine environmental research》1995,39(1-4)

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