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61.
Helmut Wolf 《Journal of Geodesy》1963,37(2):149-163
Ohne Zusammenfassung
Communication présentée à l'Assemblée générale de l'Association Internationale de Géodésie (Helsinki 1960). 相似文献
62.
63.
The organic analysis of the murchison meteorite 总被引:1,自引:0,他引:1
The organic compounds released from the Murchison carbonaceous chondrite following vaporization-pyrolysis at 150, 300 and 430°C were investigated. The total organic yield was 272 ppm and consisted of n-alkanes, alkenes, aromatic hydrocarbons and thioaromatics. The composition and yield at all three temperatures are compared with those obtained by an identical analysis on another carbonaceous chondrite, Allende, and two terrestrial rocks.Comparison of compounds released by 150°C volatilization of Murchison and Allende reveals remarkable similarities, suggesting commonality in the processes responsible for their formation. The origin of the organic compounds found can be explained in terms of the Fischer-Tropsch synthesis followed by partial equilibration of the primary products. However, problems concerning the relationship between types of carbonaceous chondrites remain unresolved. 相似文献
64.
Wolf Tietze Gerhard Kortum W. R. Mead T. K. Poiker C. Paddick George Kish A. Njøs H. Mensching V. Haarmann Uzo M. Igbozurike M. M. Yoshino Mushtaqur Rahman Lage Wahlström J. Connell Kazimierz Dziewonski Wayland R. Swain J. Humlum G. W. Lüttig Haruko Kishimoto Mai Britt E. Mørk 《GeoJournal》1982,6(3):270-280
65.
66.
This study demonstrates that oxalate has a strong inhibiting effect onFe-catalyzed S(IV) oxidation by oxygen in aqueous solution. While thepseudo-first order rate constant of S(IV) oxidation was determined to be1.6 × 103 M-1 s-1 in experimentswithout oxalate, the oxidation of S(IV) was totally inhibited at a molarconcentration ratio of iron:oxalate = 1:5 at an oxalate concentration of 4M. Under these conditions, the Fe(II)/Fe(III) ratio remained nearlyconstant during the observed reaction time. The determined rate constants wereindependent of the initial oxidation state of iron. However, with increasingconcentrations of oxalate, a longer induction period is observed forexperiments with iron initially in the Fe(II) oxidation state. 相似文献
67.
Oliver Montenbruck Christoph Günther Sebastian Graf Miquel Garcia-Fernandez Johann Furthner Hanspeter Kuhlen 《GPS Solutions》2006,10(2):146-153
In late December 2005 the GIOVE-A test satellite was launched by the European Space Agency (ESA) to secure the frequencies for the Galileo system and to provide a platform for testing the new navigation signals. We performed an initial assessment of these signals using the 30 m deep space antenna of the DLR ground station in Weilheim (Germany). The antenna gain raised the signals above the noise level, thus allowing a detailed analysis even without knowledge of the ranging codes. The present paper covers the analysis of the L1/E1 signals, which includes a discussion of the spectrum, the time domain signal and a decoding of the spreading codes for the Open Service. 相似文献
68.
We review the historical, geological, tide-gauge, GPS and gravimetric evidence advanced in favour of, or against, continuing
land uplift around Hudson Bay, Canada. We also reanalyse the tide-gauge and GPS data for Churchill using longer time series
than those available to previous investigators. The dependence of the mean rate of relative sea-level change obtained from
the tide-gauge record on the length and mid-epoch of the observation interval considered is investigated by means of a newly
developed linear-trend analysis diagram. For studying the shorter-period variability of the tide-gauge record, the wavelet
transform is used. The mean rate of land uplift obtained from GPS is based on a new analysis using IGS solutions of GFZ. To
include the post-glacial land uplift, sea-level indicators from the Churchill region representing the relative sea-level history
during the past 8000 years are also used. Finally, the values of the four observables are jointly inverted in terms of mantle
viscosity. The optimum values are ~3.2 × 1020 Pa s and ~1.6 × 1022 Pa s for the upper- and lower-mantle viscosities, respectively. 相似文献
69.
In 1988, four states in the northeastern USA commissioned a study to address land use changes in the Northern Forest, 26 million acres of temperate and boreal forest extending from Maine to eastern New York State. Against a backdrop of economic destabilization and concerns regarding social and ecological implications of a real estate boom, the sustained deliberative dialogue catalyzed by this study has come to rely heavily on the ambiguous concept of “working forest.” To clarify political and environmental dynamics in the region, we analyzed how people respond to and seek to capitalize on the interpretive flexibility of the term working forest. We combine an analysis of socio-political discourses of working forest based on a structured literature review with an assessment of local peoples’ definitions of working forest based on a survey conducted in a pair of contrasting New York State communities. The first study site represents an amenity-oriented community (i.e. a place where the forest supports a service economy including recreation and tourism) and the other study site represents a timber-dependent community. By linking data from community-level analysis to data derived from a general analysis of forest politics, we seek to develop a more robust perspective. By comparing discourses across differently structured communities, we investigate how local forest politics are mediated by local economic development processes. Our study empirically illustrates contested and geographically uneven processes of social construction of environment and rural development in a region confronting pressures of globalization. Results indicate that timber harvesting is a heavily privileged management objective, as a logic of ‘the forest that pays is the forest that stays’ dominates. Environmental politics in the region, and perhaps more generally, increasingly conforms to a form of pragmatism in which economic opportunities structure conservation planning and investment. 相似文献
70.
Metamictization and U-PB isotopic discordance in single zircons: a combined Raman microprobe and SHRIMP ion probe study 总被引:7,自引:0,他引:7
Summary We report results of a combined SHRIMP ion microprobe and Raman microprobe study of the correlation between metamictization and U-Pb isotopic discordance of zircon. The spatial resolution of the SHRIMP and Raman probe used are about 200 m3 and 80 m3, respectively. This allows a direct comparison of U-Pb isotopic discordance and metamictization of small areas within zircon crystals. We show that the impact of the oxygen ion beam on the zircon during the SHRIMP analysis does not cause significant amorphization or recrystallization in the remaining zircon on a scale of 1 m. Consequently, it is possible to determine the initial degree of metamictization of zircon within and adjacent to a SHRIMP analytical spot by Raman microprobe measurements after performing SHRIMP analyses. A combination of the two microprobe techniques gives information on the concentration and distribution of radionuclides as well as the degree of metamictization and its heterogeneity and the lateral age distribution within the grain. We found that the degree of U-Pb isotopic discordance correlates closely with the degree of metamictization within single zircon grains, on a scale of 15 m, which is consistent with previous results on the scale of single and multiple zircon grains showing that metamictization enhances the relative potential for secondary loss of radiogenic lead in zircon.
Metamiktisierung und U-Pb-Isotopendiskordanz in Einzelzirkonen: eine komplexe Untersuchung mittels Ramanmikrosonde und SHRIMP Ionensonde
Zusammenfassung Wir präsentieren die Ergebnisse einer Untersuchung des Zussammenhangs von Metamiktisierung und U-Pb Isotopendiskordanz in Zirkonen mittles kombinierter SHRIMP-Ionenmikrosonden- und Ramanmikrosondenanalysen. Die räumliche Auflösung der verwendeten Analysensysteme, experimentell mit 200 m3 (SHRIMP) und 80 m3 (Ramansonde) bestimmt, gestattet den direkten Vergleich der in Mikrobereichen innerhalb von Zirkon-Einkristallen gemessenen Isotopendiskordanzen und Metamiktisierungsgrade. Wir zeigen, daß der während der SHRIMP-Analyse auf den Zirkon einwirkende Sauerstoffionenstrahl weder signifikante Amorphisierung noch Rekristallisation des benachbarten Zirkonmaterials im 1 m-Bereich hervorruft. Es ist deshalb möglich, den Grad der Metamiktisierung eines Zirkon-Mikrobereiches auch in den SHRIMP-Analysengrübchen, d.h. erst nach dem Analysieren dieses Bereiches mit der Ionensonde, mittels hochauflösender Ramanmessungen unverfälscht zu bestimmen. Der Einsatz beider Mikromethoden liefert kombinierte Informationen zu den Gehalten und Verteilungen radioaktiver Elemente, zum Grad der Metamiktisierung und seiner Heterogenität und zur lateralen Altersverteilung innerhalb von Einzelkörnern. Wir weisen eine deutliche Korrelation des Grades der U-Pb-Isotopendiskordanz mit dem Grad der Metamiktisierung im Mikrobereich (15 m Auflösung) nach. Dies stimmt mit früheren, an Einzelzirkonen und Populationen getätigten Beobachtungen überein, daß die Metamiktisierung von Zirkon dessen Potential zu sekundären Bleiverlusten erhöht.相似文献