Des expériences de thermophotocourants et d'absorption optique sur des cristaux de BaTiO3 montrent que les ions 3d coordinés octaédriquement jouent un rôle fondamental sur les propriétés diélectriques et structurales. Les expériences d'irradiation laser fournissent une alternative intéressante pour l'étude des systèmes vibroniques.
On montre qu'un modèle à 2 niveaux d'impuretés, dans le titanate de baryum dopé au fer, au cobalt ou au cuivre, considéré comme un semi-conducteur à large bande interdite, permet d'expliquer qualitativement les courants et les photocourants observés. Les valeurs numériques des paramètres ne semblent pas être satisfaisantes.
Le tellurure de zinc est un des semiconducteurs ayant un rendement élevé de luminescence dans le vert s'il est convenablement dopé (P ou Li). L'effet Hall et la photoluminescence ont été mesurés sur des cristaux de ZnTe contenant entre 1017 et 5 x 1019 cm-3 de phosphore. La croissance de la concentration de porteurs dans le domaine de température 3...
A theoretical model is proposed which allows the calculation of the concentration of defects in pure and halogen compensated cadmium telluride grown by the THM method. All associations and ionization reactions are described in terms of the law of mass action. The ionization energies of the defects are taken from the energy level diagram established...
Published in Zeitschrift für Naturforschung B
Silylated diamines and diimines of type 13, 14 and 9-11 react with sulfur chlorine compounds SCl2, SOCl2, 8 and 12 to give 1-7 as linear S-N polymers with p-phenylen groups. Subsequent doping with acceptors (I2, Br2, AsF5) increases conductivity of 1-5 to ca. 10-4Ω-1cm-1.
Published in Zeitschrift für Naturforschung B
The polymeric μ-oxo-(tetraalkylphthalocyaninato)-metal IV B derivatives 1 a-d were synthesized by thermal condensation of the monomeric dihydroxo(tetraalkylphthalo-cyaninato)-metal IV B compounds 5 a-d. The high solubility of the metaloxanes 1 a-d enables a homogeneous reaction with the dopant. The electrical conductivities of the undoped and doped...
Published in Analytica Chimica Acta
Room-temperature phosphorescence (RTP) characteristics of 27 banned drugs in sport on Whatman No. 1 filter paper were studied. Several heavy-atom perturbes, including I −1, Tl + and Pb 2+, and the effect of pH were investigated. Optimum experimental conditions for every case were evaluated. The phase plane method was applied to the determination of...
Published in Analytica Chimica Acta
A rapid method is described for the identification and determination of ethacrynic acid in human urine samples by liquid chromatography with UV detection, the retention time of the analyte being 4.9 min. The samples were previously conditioned using C 18 solid-phase extraction columns and chromatographed on an HP-LiChrospher RP C 18 column (5 μm; 1...
Published in Analytica Chimica Acta
In 1989, 3 cases out of 20 were found where gas chromatography—mass spectrometry revealed the presence of nandrolone metabolites in the urine of untreated persons. Although the origin of the nandrolone metabolites was uncertain at that time, the presumption was that such findings could be related to the consumption of meat from nandrolone-treated a...
