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Digitale Medien

The effect of arsenic vapour species on electrical and optical properties of GaAs grown by molecular beam epitaxy (1982)

Künzel, H. ; Knecht, J. ; Jung, H. ; [weitere]

Springer

Applied physics 28 (1982), S. 167-173

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ISSN: 1432-0630

Schlagwort(e): 68.55.+ b ; 71.55.-i ; 72.20.-i ; 78.55.-m

Quelle: Springer Online Journal Archives 1860-2000

Thema: Maschinenbau , Physik

Notizen: Abstract Hall effect, DLTS and low-temperature photoluminescence measurements were used to study the effect of dimeric (As2) vs tetrameric (As4) vapour species on the electrical and optical properties of nominally undoped and of Ge-doped GaAs layers grown by molecular beam epitaxy (MBE). The arsenic molecular beam was generated from separate As2 and As4 sources, respectively, and from a single source providing an adjustable As2/As4 flux ratio. The occurence of the previously described defect related bound exciton lines in the luminescence spectra at 1.504–1.511 eV was found to be directly correlated with the presence of three deep states (M1, M3, M4) which are characteristic of MBE grown GaAs. The intensity of the extra luminescence lines and simultaneously the concentration of the deep electron traps can be reduced substantially simply by decreasing the As4/As2 flux ratio. The incorporation of defect related centers as well as of amphoteric dopants like Ge strongly depends on the surface chemistry involved. Therefore, a considerably lower autocompensation ratio in Ge-dopedn-GaAs is obtained with As2 molecular beam species which provide a higher steady-state arsenic surface population.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00617982

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Digitale Medien

Polymer-entrapped rhizobium as an inoculant for legumes (1982)

Jung, G. ; Mugnier, J. ; Diem, H. G. ; [weitere]

Springer

Plant and soil 65 (1982), S. 219-231

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ISSN: 1573-5036

Schlagwort(e): Alginate ; Carob gum ; France ; Inoculant ; Nodulation ; Polyacrylamide ; Polymer ; Rhizobium japonicum ; Senegal ; Soja ; Xanthan

Quelle: Springer Online Journal Archives 1860-2000

Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft

Notizen: Summary Field and cylinder experiments conducted in France and in Senegal showed that polyacrylamide, previously proposed as an entrapping gel for preparing Rhizobium inoculants, could be replaced by alginate (AER inoculant) or a mixture of xanthan and carob gum (XER inoculant). Semi-dried or dried AER and XER were used successfully provided that their storage time was less than 90 days. In soil inoculation trails, no marked differences were observed among semi-dried XER, dried AER, and dried XER. A number of seed inoculation experiments indicated that dried XER significantly outranked AER. Seeds preinoculated by up to 48 days with XER yielded plants which were comparable in nodulation and growth parameters to those derived from plant receiving peat inoculation at the time of planting.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF02374652

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Digitale Medien

Alder-Frankia interaction and alder-poplar association for biomass production (1984)

Teissier du Cros, E. ; Jung, G. ; Bariteau, M.

Springer

Plant and soil 78 (1984), S. 235-243

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ISSN: 1573-5036

Schlagwort(e): Alnus ; Frankia ; N2-fixation ; Mixed stands ; Populus

Quelle: Springer Online Journal Archives 1860-2000

Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft

Notizen: Summary Alders have an important role to play in biomass producing stands because of their N2-fixing ability and their capacity to withstand soils having an excess of moisture. The objectives of preliminary trials were (1) to find if there is any alder-genotype xFrankia-strain interaction when the effect of inoculating the bacteria was compared to no inoculation in seed beds of different species and provenances of alder, (2) to measure the possible effect of black alders interplanted in poplars compared to pure poplar plots. Two trials were laid out to study the alder-Frankia interaction. Both produced interaction. In the first one the inoculation had a favorable effect onAlnus glutinosa at age 2 years andA. cordata at age 1 and 2 and no effect onA. rubra. In the second one the inoculation had a depressive effect at age 1 on 2 of 3 provenances ofA. rubra and no effect on 1A. rubra, 3A.glutinosa and 3A. cordata provenances. A closely spaced field trial associating one black alder provenance and the poplar clone UNAL gives no superiority of mixed plots compared to pure plots. The results suggest that the N2-fixation of alders is not profitable to poplars at age 3 with a 1.5×2 m spacing.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF02277854

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Digitale Medien

Bestimmung von Seltenen Erden und anderen Spaltprodukten in frisch bestrahlten Kernbrennstoffen nach DC-Trennung und Anreicherung (1980)

Jung, K. ; Specker, H.

Springer

Fresenius' Zeitschrift für analytische Chemie 300 (1980), S. 15-17

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ISSN: 1618-2650

Schlagwort(e): Best. von Seltenen Erden ; Spaltprodukten in Kernbrennstoffen ; Chromatographie ; Dünnschicht

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie

Beschreibung / Inhaltsverzeichnis: Zusammenfassung Frisch bestrahlte Kernbrennstoffe werden in konz. Salpetersäure gelöst und mit dem Laufmittel Diethylether/Bis-(2-ethylhexyl)phosphat/ Salpetersäure (100∶3∶2) chromatographiert. Die Seltenen Erden werden nach der Trennung γ-spektroskopisch bestimmt. Bei zweidimensionaler DC-Trennung mit den Laufmitteln Di-iso-propylether/Tetrahydrofuran/Salpetersäure (100∶80∶4) im ersten und Diethylether/Bis-(2-ethylhexyl)phosphat/Salpetersäure (100∶4∶2) im zweiten Lauf wird eine quantitative Trennung der S.E. von allen anderen radioaktiven Spaltprodukten erreicht. Die Nachweisgrenzen wurden bestimmt und die absoluten Mengen der entstandenen S.E. berechnet. Die Trennung und Bestimmung dauert nach Lösen der Proben 60–70 min.

Notizen: Summary Nuclear fuels of short decay times are dissolved in concentrated nitric acid and analysed by thin-layer chromatography in diethylether/bis-(2-ethylhexyl)phosphate/nitric acid (100∶3∶2). Rare earth elements (RE) are determined after separation by γ spectroscopy. By two-dimensional thin-layer separation in di-isopropylether/THF/nitric acid (100∶80∶4) and diethylether/bis-(2-ethylhexyl)phosphate (100∶4∶2) a quantitative separation of the RE from all other fission products is achieved. Detection limits are determined and the absolute amounts of RE are estimated. Separation and detection after dissolving of the samples require 60–70 min.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00498708

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