Solarization mechanism of glass containing Ce3+ and As5+

The solarization mechanism in a glass containing both Ce³⁺ and As⁵⁺, 16Na₂O·11CaO·73SiO₂:0.15AsO_x·0.015CeO_x (in mol.%), is newly proposed by elucidating the valence and coordination structure of arsenic after the photochemical reaction, the mechanism being traditionally expressed as

$\text{2}\text{Ce}{}^{\mathrm{3+}}\text{+}\text{As}{}^{\mathrm{5+}}\text{→}\text{hv}\text{2}\text{Ce}{}^{\mathrm{4+}}\text{+}\text{As}{}^{\mathrm{3+}}$

ESR hyperfine quartets due to an As⁴⁺ ranging from 0.1 to 0.5 T built up on UV-irradiation and their line shape varied with the duration of the irradiation. The line shape analysis of the ESR spectra employing a computer simulation technique has led to the following conclusions; (1) As⁵⁺ is reduced to As⁴⁺ in the solarization process. (2) The geometry around the As⁴⁺ in the solarized glass is tetrahedral during the early stage and trigonal-pyramidal during the latter stage of the reaction.     

Iodine catalyzed reduction of arenesulfonic acid to the arenethiol with triphenylphosphine

Arenesulfonic acids, its sodium salts, and alkyl arenesulfonates were reduced readily to the corresponding arenethiols quantitatively with triphenylphosphine in the presence of iodine.     

Trimethylsilylmethyl derivatives of thallium(III)

Some trimethylsilylmethyl derivatives of thallium(III) have higher stability and unusual coordination behavior in comparison with simple alkylthallim(III) analogs for steric reasons.     

Correction method for X-ray fluorescent determination of chromium in high-alloy steels and nickel-base alloys

Summary A new interelement correction method has been developed for the X-ray fluorescent determination of chromium in high-alloy steels and nickel-base alloys. The calibration equation which was derived from the JIS (Japanese Industrial Standards) model is applicable over wide ranges of compositions by preparation of only Fe-Cr binary standards.The new approach gave better accuracy than that based on Rasberry-Heinrich correction model. The accuracies (_d) were 0.08% for high-alloy steels and 0.14% for nickel-base alloys.

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Korrekturmethode für die röntgenfluorescenzspektrometrische Bestimmung von Chrom in hochlegierten Stählen und Nickellegierungen

Zusammenfassung Die Eich-Gleichung für das neue Korrekturverfahren wurde vom JIS-Modell (Japanese Industrial Standards) abgeleitet und ist über einen weiten Bereich von Zusammensetzungen durch Herstellung von lediglich binären Fe-Cr-Standards einsetzbar. Das beschriebene Verfahren bietet eine bessere Genauigkeit als die Methode nach dem Korrekturmodell von Rasberry-Heinrich. Sie betrug 0,08% für hochlegierte Stähle und 0,14% für Nickellegierungen.

     

Theoretische und experimentelle Untersuchungen an Tandem-Pumpengittern starker Umlenkung

Ohne ZusammenfassungGekürzte Fassung der von der Fakultät für Maschinenwesen der Technischen Hochschule Braunschweig genehmigten gleichnamigen Dissertation. Berichter: Prof. Dr. H. Schlichting; Mitberichter: Prof. Dr. H. Petermann. Die Untersuchungen wurden im Institut für Strömungsmechanik der Technischen Hochschule Braunschweig unter der Leitung von Prof. Dr. H. Schlichting durchgeführt und durch die Deutsche Forschungs-gemeinschaft und ein Stipendium des Verfassers vom Deutschen Akademischen Austauschdienst ermöglicht.Bei der Abfassung dieser gekürzten. Fassung hat Herr Dr.-Ing. K. Gersten mitgewirkt.     

Invariability,hesitation or restoration of damage in wet-dry fatigue process

The effects of corrosive wet conditions on the progress of fatigue were studied by means of wet-dry two-stage tests of same stress level. Some results from the two-state tests—invariability, hesitation, etc., during the progress of fatique fracture—are discussed on the basis of results of measurements made on corrosionfatigue cracks and anlaysis by the equations of crack propagation. Several new methods for measurement of corrosionfatigue cracks were developed for this purpose.     

Lévy-type complex diameter modulation in semiconductor nanowire growth

We have observed a non-periodic diameter modulation in SiC nanowire growth. The modulation was tentatively attributed to a stick-slip motion in a self-organized vapor-liquid-solid (VLS) growth, and was characterized by methods of time-series analysis. From the power-law decay behavior of a fat tail of the probability distribution of increments with the exponent 2.1±0.2, the modulation was interpreted as a Lévy flight. The degree of determinism is also discussed.