Letter to the Editor: Comment on “Logratio Analysis and Compositional Distance” by J. Aitchison, C. Barceló-Vidal, J. A. Martín-Fernández, and V. Pawlowsky-Glahn     

Sönke Rehder  Ulrich Zier 《Mathematical Geology》2001,33(7):845-848

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Limnological description of the Lakes Zürich, Lucerne, and Cadagno     

Peter Bossard  Sonja Gammeter  Christine Lehmann  Ferdinand Schanz  Reinhard Bachofen  Hans-Rudolf Bürgi  Daniel Steiner  Ulrich Zimmermann 《Aquatic Sciences - Research Across Boundaries》2001,63(3):225-249

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Über das Vorkommen verschiedener Arten der GattungCyclops (s. restr.) in schweizerischen Seen     

Friedrich Kiefer  Ulrich Einsle 《Aquatic Sciences - Research Across Boundaries》1962,24(1):44-48

Ohne Zusammenfassung  相似文献   

Heavy metal accumulation in river sediments: A response to environmental pollutionSchwermetall-anreicherung in fluviatilen sedimenten als ausdruck der verschmutzung unserer umwelt     

Ulrich Förstner  German Müller 《Geoforum》1973,4(2):53-61

As evidenced by catastrophic cadmium and mercury poisonings in japan, heavy metals belong to the most toxic environmental pollutants. Through the investigation of sediments, the extent, distribution and provenance of heavy metal contamination in rivers and lakes can be determined and traced. Eight heavy metals from the clay fraction of sediments from major rivers within the Federal Republic of Germany were determined by means of atomic adsorption spectrometry. Heavy metals especially known for their high toxicity are enriched most: mercury, lead and zinc by a factor of 10; cadmium by a factor of 50, as compared with the natural background of these elements. A mobilisation of heavy metals from the suspended load and from the sediments, as to be observed in rivers approaching the marine enviromment, could endanger marine organisms, thus negatively influencing the acquatic food chain. With a further increase of heavy metal pollution, a threat to the drinking water supplied by rivers and lakes cannot be excluded.  相似文献   

Untersuchungen zur Morphologie des Schelfrandes vor Mozambique nordöstlich der Sambesi-Mündung     

Dr. Johannes Ulrich  Dr. Horst Pasenau 《Ocean Dynamics》1973,26(5):216-225

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Structural phase transition in titanite,CaTiSiO5: A ramanspectroscopic study     

Ekhard Salje  Claudia Schmidt  Ulrich Bismayer 《Physics and Chemistry of Minerals》1993,19(7):502-506

The structural phase transition in titanite is correlated with a strong temperature dependence of Raman scattering cross sections and, to a somewhat lesser extent, with shifts of the phonon frequencies. Their quantitative temperature evolution in the low-symmetry phase (P2₁/a) is compatible with a nearly 2D Ising behaviour with β≈0.12 and T _c = 497 K. At temperatures above 860 K, the phonon signals agree with A 2/a symmetry but not in the temperature interval between 497 K and 860 K. In this temperature range new structural states give rise to additional phonon signals. A model based on mobile APBs between slabs of P2₁/a material, first proposed by van Heurck et al. (1991), is in qualitative agreement with our experimental observations.  相似文献   

An experimental study of the titanomagnetite solid solution series     

Ulrich Bleil 《Pure and Applied Geophysics》1976,114(2):165-175

Summary Analysis of saturation magnetization measurements and data from the literature indicate that the cation distribution in the titanomagnetite solid solution series is temperature dependent. The ionic configuration of ferric and ferrous ions on both lattice sites of their spinel structure can be described by a modified Boltzmann relation in agreement with theoretical consideratios. Thermodynamic equilibrium isotherms for the cation distribution and the resulting variation of saturation magnetization are calculated on the basis of the experimental values. These results should be especially valuable for the interpretation of magnetic properties of rapidly cooled igneous rock units where a respective high-temperature metastable state may exist in the magnetic ore component.Further measurements of the Curie temperature and lattice constant did not confirm a similar effect. Both these parameters should therefore be qualified for the identification of naturally occurring titanomagnetites.  相似文献   

Noble-gas-rich separates from the Allende meteorite     

Ulrich Ott  Ruth Mack 《Geochimica et cosmochimica acta》1981,45(10):1751-1788

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Prediction of algal growth in batch cultures     

Ferdinand Schanz  Ulrich Zahler 《Aquatic Sciences - Research Across Boundaries》1981,43(1):103-113

The growth of algae in batch cultures is often well characterized by the logistic growth function. The equation used contents three parameters which have to be estimated. Two methods are presented: The linearizing procedure, and the direct method of least squares. We give an example for comparing several logistic growth curves.  相似文献   

Das 150-kHz-Fächerlot des Forschungsschiffes „Poseidon” und seine ersten Meßergebnisse     

Dr. Johannes Ulrich 《Ocean Dynamics》1980,33(6):236-254

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