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991.
Summary The results obtained for halogen absorption with different preparations of lead chromates are discussed. It has been found that pure lead chromate is a poor external absorbent for microanalytical determinations of halogens. Differences in the absorption properties of lead chromates of various origins can be explained by the presence of PbO · PbCrO4 and by its different mechanical structures.
Absorptionseigenschaften handelsüblicher Bleichromate
Zusammenfassung Die Ergebnisse der Halogenabsorption an Bleichromat verschiedener Herkunft werden diskutiert. Dabei wurde festgestellt, daß reines Bleichromat für mikroanalytische Halogenbestimmungen unzureichend ist. Unterschiedliche Absorptionseigenschaften dieser Verbindung können durch das Vorhandensein von PbO · PbCrO4 sowie durch die verschiedene mechanische Struktur erklärt werden.相似文献
992.
K. Mayrhofer N. Hofreiter W. Nöbauer F. Hohenberg K. Prachar H. Hornich E. Hlawka H. Brauner W. Gröbner 《Monatshefte für Mathematik》1959,63(1):84-100
Ohne Zusammenfassung 相似文献
993.
J.M. Dauria J.W. Grüter E. Hagberg P.G. Hansen J.C. Hardy P. Hornsh?j B. Jonson S. Mattsson H.L. Ravn P. Tidemand-Petersson 《Nuclear Physics A》1978,301(3):397-410
Neutron-deficient caesium isotopes with mass numbers from 114 to 118 have been studied at the ISOLDE facility. Half-lives have been determined from counting of β-particles, β-delayed protons, and γ-rays. A short-lived isomer () in 116Cs has been observed and the new delayed-particle precursors 116Cs (protons and α-particles), 115Cs (protons), and 114Cs (protons and α-particles) have been identified. Coincidences between delayed particles and γ-rays have been measured for 118Cs (pγ and αγ) and 116Cs (pγ). A search for the possible proton-radioactive isotope 113Cs has been performed and an upper limit for its production yield is given. 相似文献
994.
Iminium salts 3 and 5 are accessible by alkylation or protonation of β-alkoxycarbonyl-enamines. They have been isolated and characterized by 1H NMR spectra. Their reaction products formed with nucleophiles such as organomagnesium or CH-acidic compounds (dimedone, acetophenone), are also investigated and shown partly to undergo secondary reactions under amine elimination. 相似文献
995.
Structure Elucidation of a Dimethylfulvene-trimer. Evidence for a [6+ 4]-Dimerization of 6, 6-Dimethylfulvene Thermal reaction of pure 6, 6-dimethylfulvene ( 1c ) at 60° gives an oligomeric mixture consisting mainly of fulvene-trimers. The structure of the main product 3c is partially elucidated by 1H-NMR. investigations at 400 MHz and definitely confirmed by X-ray analysis. The formation of 3c is explained in terms of a [6+4] dimerization, followed by a 1, 5-proton-shift and a final Diels-Alder reaction. 相似文献
996.
997.
Chloroacylation and Bromoacylation of Carbonyl Compounds III. Reactant/Product Equilibria Aliphatic, α, β-unsaturated and aromatic aldehydes 1 as well as aliphatic ketones react with acyl halides 2 to α-haloalkyl esters 3 . In the presence of Lewis acids there is an equilibrium between reactants and product. The position of the equilibrium depends on the nature of the carbonyl compound as well as that of the acyl halide: The products 3 are favoured in the case of aldehydes, cyclobutanone and cyclohexanone, and the equilibrium constant increases in the series F < Cl < Br < I. Low reaction temperature, nonpolar solvents as well as high reactant concentrations favour the product 3 . 相似文献
998.
This is a study of the problem, which stochastic processes could arise from dynamical systems by loss of information. The notions of “dilation” and “approximate dilation” of a stochastic process are introduced to give exact definitions of this particular relationship. It is shown that every generalized stochastic process is approximately dilatable by a sequence of dynamical systems, but for stochastic processes in full generality one needs nets. 相似文献
999.
Ohne Zusammenfassung 相似文献
1000.