IN-FLIGHT PERFORMANCE OF THE VIRGO LUMINOSITY OSCILLATIONS IMAGER ABOARD SOHO     

Appourchaux  Thierry  Andersen  Bo N.  Fröhlich  Claus  Jiménez  Antonio  Telljohann  Udo  Wehrli  Christoph 《Solar physics》1997,170(1):27-41

The Luminosity Oscillations Imager (LOI) is a part of the VIRGO instrument aboard the Solar and Heliospheric Observatory (SOHO). The scientific objective of the LOI experiment is to identify and characterize pressure and internal gravity oscillations of the Sun by observing the radiance variations. The LOI is a low-resolution imager with 12 pixels, for the measurement of the radiance distribution over the solar disk at 500 nm. The low resolution capability of the instrument allows the identification of individual azimuthal orders for l = 0 to 7, without suffering the mixing that affects integrated solar disk instruments. The performance, calibrations and instrumental effects of the LOI are described together with the procedures for extracting the solar p modes.  相似文献   

The H₂O and CO₂ adsorption properties of phyllosilicate-poor palagonitic dust and smectites under martian environmental conditions     

Jochen Jänchen  Richard V. Morris  David L. Bish  Mareike Janssen  Udo Hellwig 《Icarus》2009,200(2):463-467

The recent detection of up to ∼10 wt% water-equivalent H heterogeneously distributed in the upper meter of the equatorial regions of the martian surface and the presence of the 3-μm hydrations feature across the entire planet raises the question whether martian surficial dust can account for this water-equivalent H. We have investigated the H₂O and CO₂ adsorption properties of palagonitic dust (<5 μm size fraction of phyllosilicate-poor palagonitic tephra HWMK919) as a martian dust analog and two smectites under simulated martian equatorial surface conditions. Our results show that the palagonitic dust, which contains hydrated and hydroxylated volcanic glass of basaltic composition, accommodates significantly more H₂O under comparable humidity and temperature conditions than do the smectites nontronite and montmorillonite.  相似文献   

Tournaisian age of granitoids from the Odra Fault Zone (southwestern Poland): equivalent of the Mid-German Crystalline High?     

Wolfgang Dörr  Andrzej Żelaźniewicz  Paweł Bylina  Janina Schastok  Wolfgang Franke  Udo Haack  Cyprian Kulicki 《International Journal of Earth Sciences》2006,95(2):341-349

The Odra Fault Zone of southwestern Poland is a NW-trending horst marked by gravimetric and magnetic anomalies and composed of high- to low-grade metamorphic and igneous rocks which are only known from boreholes. This zone embraces a concealed border between Variscan internides and externides. It also contains an array of several I-type, metaluminous to peraluminous, high potassic granitoid bodies which intruded earlier metamorphosed rocks. Except for one case, they remain unfoliated and undeformed, and presumably play a role of stitching plutons at the suture between two obliquely colliding terranes. U–Pb TIMS dating of single zircons from one foliated and one unfoliated granitoid samples yielded identical concordant ages of 344±1 Ma (Tournaisian). They resemble a Pb–Pb age of 350±5 Ma obtained for S-type granitoids from the Luckau area further west in Germany, which is generally regarded as an eastern segment of the Mid-German Crystalline High. Carboniferous granitic intrusions in the high are generally younger (340–290 Ma). Correlations of the the Odra Fault Zone with the Mid-German Crystalline High appear plausible, but by no means certain and require further confirmation.  相似文献   

Changes in Vascular Plant Biodiversity in the Netherlands in the 20th Century Explained by their Climatic and other Environmental Characteristics     

Wil L. M. Tamis  Maarten Van't Zelfde  Ruud Van Der Meijden  Helias A. Udo De Haes 《Climatic change》2005,72(1-2):37-56

In the Netherlands nation-wide databases are available with about 10 million records of occurrences of vascular plant species in the 20th century on a scale of approximately 1 km². These data were analysed with a view to identifying relationships between changes in botanical biodiversity and climatic and other environmental factors. Prior to analysis the data were corrected for several major forms of survey bias. The records were broken down into three periods: 1902–1949, 1975–1984 and 1985–1999. Using multiple regression analysis, differences between successive periods were related to plant functional characteristics as explanatory variables. Between the periods 1902–1949 and 1975–1984 there were small but significant increases in the presence of both thermophilic (‘warm’) and psychrophilic (‘cold’) species. However, in the final decades of the 20th century there was a marked increase in thermophilic species only, coinciding with the marked increase in ambient temperature observed during this period, evidence at least of a rapid response of Dutch flora to climate change. Urbanisation was also examined as an alternative explanation for the increase in thermophilic plant species and was found to explain only 50% of the increased presence of such species in the final decades of the 20th century. Besides temperature-related effects, the most important change during the 20th century was a strong decline in oligotrophic and a marked increase in eutrophic plant species.  相似文献   

Iodine as a tracer of organic material: I results from gas hydrate systems and fore arc fluids     

U. Fehn  G.T. Snyder  Y. Muramatsu 《Journal of Geochemical Exploration》2007,95(1-3):66

The strong association of iodine with organic material and the presence of the cosmogenic radioisotope ¹²⁹I make the iodine isotopic system useful in tracing and dating organic materials and their derivatives. We present here results from two new applications of this system, investigations of gas hydrates from the Peru Margin (ODP Leg 201, Site 1230) and of fluids collected from the fore arc region of the North Island, New Zealand. Pore fluids from Site 1230 are strongly enriched in iodine and show a distinct decrease in ¹²⁹I/I ratios from 920 × 10^− 15 close to the surface to 140 × 10^− 15 at a depth of 200 mbsf, suggesting the presence of a shallow, young source and deep, old source of fluids. The fore arc fluids from New Zealand are also enriched in iodine and show a similar range in ¹²⁹I/I ratios. In both cases minimum ages are calculated to be between 40 and 60 Ma for these fluids. The results are in good agreement with earlier investigations of gas hydrate systems at Blake Ridge and Nankai Trough and of fore arc fluids from Central America and Japan, but are not compatible with derivation from subducting sediments in active margins. The results indicate that continental margins contain large amounts of old iodine, reflecting the presence of large quantities of organic material stored in these regions. Results for gas hydrate systems and fore arc fluids show similar characteristics, but differ strongly from those obtained for fluids collected from the main zones of volcanic activity associated with active margins.  相似文献   

Chlorine-36 in the Snake River Plain Aquifer at the Idaho National Engineering Laboratory: Origin and Implications   总被引：2，自引：0，他引：2  

T. M. Beasley  L. D. Cecil  P. Sharma  P. W. Kubik  U. Fehn  L. J. Mann  H. E. Gove 《Ground water》1993,31(2):302-310

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Spurenelemente in Biotiten aus Graniten und Gneisen     

Udo K. Haack 《Contributions to Mineralogy and Petrology》1969,22(2):83-126

91 biotites (53 from granites, 35 from highly metamorphic gneisses, 3 from redwitzites) were separated and analyzed for Fe, Mn, Zn, Cl, Sn, Ni, Co, Or, Cu, V, Mo, Pb. Biotites from gneisses contain much more Ni, Co, Cr, V but less Fe, Mn, Zn than those from granites. However, the distinction between biotites from gneisses and from granites on the basis of these elements is not certain. If a gneiss undergoes anatexis, the contents of Ni, Co, Cr, V, Zn and Sn of the preexistent biotite fractionate: Zn, Sn and Pe enter the anatectic melt readily while Ni, Co, Cr and V concentrate in the remaining matter (restite). Ni, Co, Cr and V are strongly positively correlated with one another but negatively with Fe and Zn, the latter being positively correlated with Pe. The chemical composition of biotites from granites depends not only on a potential degree of secondary decomposition into chlorite and muscovite but much more on the percentage of biotite in the rock: The more biotite, the higher the content of Ni, Co, Cr, V and the lower Fe, Zn and Sn in the biotite. Thus, it is possible to distinguish between normal and abnormal concentrations of an element in a biotite and in a rock. This might be useful in geochemical prospecting. Abnormal high concentrations of Sn and Zn were found in biotites from some granites which are connected with mineralizations of these elements. It is impossible hitherto to gain informations about the history and the parental material of a granitic magma from the minor elements in the rock or the biotite because their concentrations depend on how much biotite could be incorporated by the melt. The distribution coefficient of Cl between the lattice of 4 biotites and their fluid inclusions was determined to be 0,08.  相似文献   

Photosynthesis and respiration ofSpartina andJuncus salt marshes in North Carolina: Some models     

Udo Blum  Ernest D. Seneca  Linda M. Stroud 《Estuaries and Coasts》1978,1(4):228-238

In situ ecosystem gas exchange measurements were taken monthly for a 15-month period during low tide forJuncus roemerianus Scheele and short, medium, and tall height forms ofSpartina alterniflora Loisel. in three salt marshes near Southport, North Carolina. Multiple regression analysis was used to obtain empirical relationships betwen gas exchange values and the physical and biotic variables measured. Preliminary models for net ecosystem photosynthesis, ecosystem respiration, and respiration of aboveground standing crop were developed. Validation of models was carried out in the following manner: (1) net primary productivity of aboveground standing crop was calculated from model data and compared with harvest estimates of net primary productivity for the same year; and (2) carbon exchange and energy efficiency values were compared with literature values. In general, theSpartina models, because of their larger data base, were more useful than theJuncus models. Annual primary productivity of aboveground standing crop calculated from gas exchange values was 1.8 to 3.6 times greater forSpartian than values calculated from harvest data by Smalley's method.Juncus values were approximately equal. Since values calculated from carbon data and harvest data are not entirely equivalent, required adjustments to the carbon values are discussed. Both species have two growth periods—one in ths pring and one in the fall—with the spring growth in excess of that in the fall. Net ecosystem productivity was highest in the spring and lowest in the summer. Ecosystem respiration amounted to 71% of gross annual photosynthesis. The aboveground standing crop contributed approximately 35% to this ecosystem respiration and the soil, the remaining 36%. Efficiency for gross photosynthesis per unit of solar radiation ranged from 0.22 to 1.11%. Efficiencies for net primary production of aboveground standing crop ranged from 0 to 0.82% and those of net ecosystem production from 0 to 0.56%.  相似文献   

p.p'-DDT,Dieldrin und Polychlorierte Biphenyle (PCB) im Oberflächenwasser der westlichen Ostsee 1974     

Dr. Dieter Stadler  Udo Ziebarth 《Ocean Dynamics》1976,29(1):25-31

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The stability of fission tracks in epidote and vesuvianite     

Udo Haack 《Earth and Planetary Science Letters》1976,30(1):129-134

The stability of fission tracks in epidote and vesuvianite (idiocrase) was studied at different temperatures for several periods of time. The tracks in epidote are almost as heat-resistant as those in garnet; in vesuvianite they are much less stable. These results are in line with the rule that tracks in minerals with high lattice energies need higher activation energies to fade than in minerals with low lattice energies.  相似文献