Multi-year satellite observations of Lake Ladoga's biogeochemical dynamics in relation to the lake's trophic status

Multi-decadal extensive ship borne biochemical investigations conducted by the Limnological Institute in St. Petersburg (Russian Academy of Sciences) have shown that since the mid-1980s the ecosystem of Lake Ladoga (at that time a mesotrophic water body) has undergone significant and multifaceted alterations primarily as a result of a dramatic cutting of external phosphorus input enforced by the administrative measures taken at the Russian federal and regional levels. Using the SeaWiFS data for the time period 1998–2004, the seasonal dynamics of spatial distributions of phytoplankton chlorophyll and dissolved organic matter in Lake Ladoga have been documented and analyzed. It is shown that the hydro-optical characteristics of the lake's water have undergone appreciable modifications as compared to the mid-1980s. Contrary to expectations that these changes would bring about some amelioration of the lake's ecological state, ship-based and spaceborne observations indicate that the attained decrease in phosphorous input has not resulted in “healing” of the lake's ecology. It is proposed that during the lake's mesotrophic period, a specific mechanism of phosphorus release from dissolved organic matter has gradually developed. As a result, the lake's phosphorous concentrations have continued to be higher than expected. In addition changes in local atmospheric forcing are manifested not only in remotely sensed color data but also in the inter-annual behavior of the spring thermal bar derived from the AVHRR multi-year observations.     

A temperature controlled liquid crystal lens for spherical aberration compensation

A temperature controlled liquid crystal lens for spherical aberration compensation in a Blu-ray optical pickup is demonstrated and the influence of the temperature on the switching time is investigated. Using the liquid crystal BL-006, the shortest switching time is achieved at a temperature of 70°C, which corresponds to a reduction by a factor of 3 compared to 30°C. An optimum lens design would bring the switching time down to 320 ms, assuming a data-layer separation of 20 μm and an aperture diameter of 4 mm.     

Characterization of Co25Ag75 and (Co90Al10)28Ag72 granular films by electron diffraction,high-resolution transmission electron microscopy and electron spectroscopic imaging

Series of sputter-deposited Co25Ag75 and (Co90Al10)28Ag72 giant-magnetoresistance granular films were characterized by electron diffraction, high-resolution transmission electron microscopy and electron spectroscopic imaging. Crystalline particles of fcc silver and hcp cobalt were detected in both thin-film systems before annealing. Annealing of (Co90Al10)28Ag72 films at 773 and 823 K yielded mixtures of fcc and hcp cobalt clusters and notably enlarged silver particles. In addition, crystallites of bcc Ag3Al were detected in the sample annealed at 823 K. The mesoscopic structure of the as-deposited films was investigated by dark-field imaging showing columnar growth-domains for silver. The columns were preserved during thermal treatment up to 773 K, whereas annealing at 823 K destroyed these domains.     

Kultivierung von Embryonen und Single-Embryo-Transfer

Ohne Zusammenfassung

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Einfluß mechanischer Belastungen auf das Kavitationsverhalten metallischer Werkstoffe

Kritische Literaturauswertung. Kavitationsanlage für überlagerte mechanische Spannungen. Ergebnisse für die Werkstoffe technisch reines Eisen, St42-2 und G-X6 CrNiMo 1810 (1.4408). Einführung einer neuen Meßgröße zur Beschreibung des Kavitationsverhaltens sowie des additiven Spannungseinflusses. Beschreibung der ?Kavitations“-Fließgrenze. Diskussion und mathematische Formulierung der Ergebnisse.     

Characterization of ethylene homo- and copolymers

Summary For the estimation of molecular mass distribution and average molecular masses of (norbornene ethylene) copolymers a size exclusion chromatography method is described. The validity of the universal calibration function of Benoit et al. based on polystyrene molecular mass standards was confirmed by comparing with the number average molecular masses obtained by osmometry. The constants of the Mark-Houwink equation are a = 0.535, K = 1.00·10^–1 (Xylene, 90 °C) and a=0.589, K=4.93·10^–2 (diethylbenzene, 120°C,[] in cm³g^–1).Part IV: Plaste u. Kautschuk 32, 12, 444 (1985)     

West Germany's efforts to close the nuclear fuel cycle: Strategies for radioactive waste management

West Germany's efforts to reach a mature nuclear economy by [closing] the [back end] of the nuclear fuel cycle are discussed with special emphasis on radioactive waste management strategies. the radioactive wastes that would be generated in a closed nuclear fuel cycle are described. A brief discussion is given of the motives that underlie the current international disagreement regarding the desirability of, and the need for, closing the nuclear fuel cycle. West Germany's concept for closing the nuclear fuel cycle is outlined including institutional arrangements and responsibilities. A discussion of radioactive waste classification follows. Expected volumes and inventories of radioactive wastes are pointed out. Current practices, and research and development work in the treatment and disposal of radioactive wastes are outlined. A final section is devoted to the history, circumstances and implications of the current requirement for a [solution] for the back end of the nuclear fuel cycle as a precondition for continued expansion of nuclear power in West Germany.     

Ionenadsorption an Elektroden in wäßrigen und nichtwäßrigen Elektrolyten

Adsorption of ions on electrodes in aqueous and nonaqueous electrolytes . This article considers the practical implications of adsorption of electrolyte ions on electrodes and methods for quantitative determination of electrosorption of ions. Adsorbed ions influence the potential drop in the inner Helmholtz layer and thereby modify the rate of charge transfer for redox processes occurring at electrodes, and the chemical reactions ensuing upon charge transfer can be effectively directed by adsorbed ions. Corrosion and its inhibition as well as deposition of metal in electroplating can be influenced by surface-active ionic additives which are adsorbed. Measurement of differential capacity provides information about the electrosorption of ions and neutral compounds. A knowledge of the zero point of the electrode metal permits clear predictions concerning ion adsorption. Anions are preferentially adsorbed at potentials on the anodic side of the zero point, and cations at potentials that are more negative than the zero point. Surface-active neutral compounds and lyophobic ions are most strongly adsorbed in a narrow potential range around the zero point. Adsorption of weakly solvated ions on hydrophobic metals (e. g. Au, Hg) is more pronounced than the adsorption of strongly solvated ions on hydrophilic metals (e. g. Ga, Cd, Zn).