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141.
Wilh. Geilmann und Karl-Heinz Neeb 《Fresenius' Journal of Analytical Chemistry》1959,165(4):251-268
Zusammenfassung Die Verdampfungsanalyse mit spektrographischer Ermittlung des Thalliums wird zur Untersuchung fester Proben empfohlen. Einzelheiten der Durchführung des Verfahrens und Belege für die LeistungsfÄhigkeit werden aufgeführt.Für die Untersuchung von Lösungen wird die KonzentrationsfÄllung des Thalliums mit anschlie\ender Verdampfung vorgesehlagen.Für FÄlle, in denen letztere nicht unmittelbar anwendbar ist, wird das Thallium zunÄchst mit Äther extrahiert und die KonzentrationsfÄllung im Ätherextrakt vorgenommen, worauf die Verdampfung mit spektrographischem Nachweis sich anschlie\t.Durch die Verdampfung und den spektrographischen Nachweis sind Thalliummengen von 2–100 ng mit einem Fehler von maximal 30% erfa\bar und somit Gehalte bis zu 10–8% Thallium in der Probe ohne irgendwelchen Reagentienverbrauch bestimmbar.Die Bestimmung des Thalliums in Lösungen ist innerhalb der gleichen Fehlerspanne möglich.Erste Mitteilung: W. Geilmann, diese Z. 160, 410 (1958).Die vorliegende Arbeit wurde durch die von der Deutschen Forschungsgemeinschaft zur Verfügung gestellten GerÄte und durch Mittel seitens des Verbandes der chemischen Industrie ermöglicht, wofür auch an dieser Stelle gedankt sei. 相似文献
142.
Helmut Behrens Günter Landgraf Peter Merbach Matthias Moll Karl-Heinz Trummer 《Journal of organometallic chemistry》1983,253(2):217-229
The nitrosylcarbonylisonitrile complexes η5-C5H5M(NO)(CO)CNR (R = Me for Cr, Mo, W; R = Et, SiMe3, GeMe3, SnMe3 for Mo) are formed by treatment of the nitrosylcarbonylcyanometalates Na[η5-C5H5M(NO)(CO)CN] with [R3O]BF4 (R = Me, Et), Me3SiCl, Me3GeCl or Me3SnCl. The isoelectronic dicarbonylisonitrile compounds η5-C5H5Mn(CO)2CNR (R = SiMe3, GeMe3, SnMe3, PPh2, AsMe2) and η5-C5H5Re(CO)2CNAsMe2 are obtained by analogous reactions of Na[η5-C5H5M(CO)2CN] (M = Mn, Re) with Me3ECl (E = Si, Ge, Sn), Ph2PCl and Me2AsBr.With phosgene the anionic complexes Na[η5-C5H5M(CO)2CN] (M = Mn, Re) can be transformed into the new carbonyldiisocyanide-bridged dinuclear complexes η5-C5H5M(CO)2CN-C(O)-NC(OC)2M-η5-C5H5. Finally, the reactions of η5-C5H5M(NO)(CO)CNMe (M = Cr, Mo, W) with NOPF6, leading to the cationic dinitrosylisonitrile complexes [η5-C5H5M(NO)2CNMe]+, are described. 相似文献
143.
144.
Preparation, Properties, and Molecular Structures of Chiral Dimethylaluminum Amino Alkoxides Dimethylaluminium-2-piperidylmethoxide ( 1 ), N-methyl-3-piperidyloxide ( 2 ), R(–)-2-aminobutoxide ( 3 ) and cis-1 R, 2 S-2-N-benzylaminocyclohexyl-1-methoxide ( 4 ) were obtained by reaction of Me3Al with the corresponding aminoalkohols in n-pentane. The compounds were characterized by 1H, 13C, and 27Al n.m.r. spectroscopy. The molecular structures of 1 , 3 , and 4 were determined by X-ray diffraction. The compounds form oxygen-bridged dimers and in consequence of an Al–N interaction two additional chelate rings. The bond distances of the central Al2O2 ring correspond with 1.9 Å to those of known dialkylaluminumalkoxides. The Al–N bond distances run to 2.18 Å which indicates a strong EDA interaction. 相似文献
145.
146.
147.
Karl-Heinz Thiele Sergio Bambirra Joachim Sieler Svea Yelonek 《Angewandte Chemie (International ed. in English)》1998,37(20):2886-2888
Different bonding modes are characteristic for the lanthanum centers of the title compound, a trinuclear lanthanum–pyrene complex in which an arene trianion is present for the first time (see picture for the structure). Thus, La1 and La3 reside in a tetrahedral environment, the La2 center in a distorted trigonal-bipyramidal one. 相似文献
148.
Silke Tesch Karl-Heinz Rentrop Matthias Otto 《Fresenius' Journal of Analytical Chemistry》1992,344(4-5):206-208
Summary A method for the rapid characterization of brown coals based on the application of a powerful method of principal component analysis, the Partial Least Squares method (PLS), is described. A data catalogue of 44 brown coals from different deposits of East European and Asian countries was used, which lists analyses of several coal parameters. Infrared spectra of brown coals were recorded and different coal properties were predicted with the help of PLS. The results show that, with the PLS-method used, several coal properties can be predicted and it is possible to describe the classification of a coal for several technological processes. The developed method is useful because of the multiplicity of information obtained within a short time and because it is possible to replace lengthy classical methods. 相似文献
149.
Karl-Heinz Diener 《Mathematical Logic Quarterly》1993,39(1):492-514
In this paper we generalize the Dedekind theory of order for the natural numbers N to abstract algebras with arbitrarily many finitary or infinitary operations. For any algebra ??, we introduce an algebraic predecessor relation P?? and its transitive hull P*?? coinciding in N with the unary injective successor function' resp. the >-relation. For some important classes of algebras ??, including Peano algebras (absolutely free algebras, word algebras), the algebraic predecessor relation is well-founded. Hence, its transitive hull, the natural ordering >?? of ??, is a well-founded partial order, which turns out to be a convenient device for classifying Peano algebras with respect to the number of operations and their arities. Moreover, the property of well-foundedness is an efficient tool for giving simple proofs of structure theorems as, e. g., that the class of all Peano algebras is closed under subalgebras and non-void direct products. - Finally, we will show how in the case of a formal language ??, i. e., the Peano algebra ?? of expressions (= terms & formulas), relations P??, resp. P*?? can be used to define basic syntactical notions as occurences of free and bound variables etc. without any reference to a particular representation (“coding”) of the formal language. MSC: 03B22, 03E30, 03E75, 03F35, 08A55, 08B20. 相似文献
150.
Annegret Hartung Marcus R. Lisy Karl-Heinz Herrmann Ingrid Hilger Dirk Schüler Claus Lang Matthias E. Bellemann Werner A. Kaiser Jürgen R. Reichenbach 《Journal of magnetism and magnetic materials》2007
This work investigated macrophages labeled with magnetosomes for the possible detection of inflammations by MR molecular imaging. Pure magnetosomes and macrophages containing magnetosomes were analyzed using a clinical 1.5 T MR-scanner. Relaxivities of magnetosomes and relaxation rates of cells containing magnetosomes were determined. Peritonitis was induced in two mice. T1, T2 and T2* weighted images were acquired following injection of the probes. Pure magnetosomes and labeled cells showed slight effects on T1, but strong effects on T2 and T2* images. Labeled macrophages were located with magnetic resonance imaging (MRI) in the colon area, thus demonstrating the feasibility of the proposed approach. 相似文献