Rydberg fingerprint spectroscopy: a new spectroscopic tool with local and global structural sensitivity

Rydberg spectra are shown to provide a spectral fingerprint that is sensitive to molecular structure in unique ways. The concepts are demonstrated using a set of isomeric fluorophenols and a sequence of aliphatic diamines. In the fluorophenols, the sensitivity extends to the placement of a single hydrogen atom and can be traced to the molecular charge distributions associated with the locations of atoms and functional groups with respect to the charge center. Experiments on tetramethyl diamines demonstrate that the structural sensitivity encompasses the extended molecular structure, including parts of the molecule that are remote from the ionization center. This global structure sensitivity makes Rydberg fingerprint spectroscopy uniquely suited to characterize structures of large-scale molecular systems.     

Spectrochemical determination of lithium,sodium, potassium and rubidium in rocks and minerals using the stallwood jet

A D C, spectrochemical method using the STALLWOOD jet has been developed for the determination of Li, Na, K and Rb in silicate minerals and rocks. Samples are mixed with graphite and Cs₂CO₃ in tho ratio 2 : 1 : 1, and Cs serves as internal standard. Precision and accuracy is satisfactory.     

Magnetic field decoupling experiments in NO2

Magnetic field decoupling experiments in the optically excited states of NO₂ yield decoupling signals with a width of 10 to 40 mG. We attribute these signals to the non-rigidity of the excited molecule.     

R?ntgenspektrometrische Goldbestimmung in sulfidischen Erzen nach chemischer Anreicherung

Zusammenfassung Es wird eine Goldbestimmung an sulfidischen Erzen für den Bereich von 0,05–5 ppm bei 20 g Einwaage beschrieben. Das Gold wird durch Salpetersäurebehandlung von den übrigen Metallen getrennt, mit Salzsäure/ Salpetersäure gelöst und mit Selen als innerem Standard und Tellur als Spurenfänger mittels Zinn(II)-chlorid gefällt. Der Niederschlag wird auf ein Membranfilter aufgezogen. Die Goldbestimmung erfolgt über den Impulsratenquotienten der Gold L- und Selen K-Linien. Die störende Molybdän K-Strahlung und die Comptonstreuung werden durch ein Zirkoniumblech auf dem Röhrenfenster unterdrückt. Der Variationskoeffizient beträgt 20% für 0,2–5 ppm und 53,6% für 0,05 ppm.

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Summary A method is described for the determination of gold in sulphide ores within the concentration range of 0.05–5 ppm with sample weights of 20 g. Gold is separated from the other metals by treatment with nitric acid, dissolved by hydrochloric acid, containing some nitric acid, and is finally precipitated by stannous chloride applying selenium as internal standard and tellurium as collecting agent. The precipitate is mounted on a diaphragm filter and the determination of gold is carried out by X-ray analysis suppressing the disturbing Mo _K radiation and compton scattering by a zirconium sheet-metal on the X-ray tube. The pulse rate quotient of the lines Au _L /Se _K is a function of the concentration of gold. The variation coefficient is 20% for 0.2–5 ppm and 53.6% for 0.05 ppm.

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Herrn Prof. Dr.-Ing. habil. J. Hesemann zum 65. Geburtstag gewidmet.     

On the interactive solution to a multicriteria scheduling problem

Summary A mixed integer multiple criteria model is formulated for scheduling problems. Its solution is obtained by an interactive method based on the Tchebycheff-approximation. For solving greater problems some modifications are discussed at the end of the paper, which are essentially based on the notion of heuristic efficiency.

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Zusammenfassung Da bei Ablaufplanungsproblemen häufig mehrere Zielsetzungen zu beachten sind, wird im folgenden Beitrag hierzu ein gemischt-ganzzahliges multikriterielles Entscheidungsmodell formuliert. Seine Lösung erfolgt mit Hilfe eines interaktiven Verfahrens. Zur numerischen Lösung größerer Problemstellungen sind einzelne Verfahrensmodifikationen erforderlich, die im wesentlichen auf dem im letzten Abschnitt eingeführten Begriff der heuristischen Effizienz aufbauen.

     

Titration von Sulfid mit einer sulfidionensensitiven Elektrode

Zusammenfassung Eine Methode zur potentiometrischen Titration von Sulfid mit Natriumplumbat(II)lösung an einer sulfidsensitiven Membranelektrode wird beschrieben. Sie eignet sich zur Bestimmung von 10^–4% Sulfid in Gegenwart von Cl^–, Br^–, J^–, SCN^–, SO₃ ^2–, S₂O₃ ^2–

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Titration of sulphide with a sulphide-ion sensitive electrode

A method is described for the titration of sulphide with sodium plumbate(II) solution using a sulphide-sensitive electrode. The method is suitable for the determination of 10^–4% of sulphide in the presence of Cl^–, Br^–, J^–, SCN^–, SO₃ ^2–, S₂O₃ ^2–.

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Wir danken Herrn Dr. K. Obst für wertvolle Hinweise und Diskussionen.     

Perfluororganocadmium-verbindungen als sehr wirksame perfluoralkylierungs- und perfluorphenylierungsmittel zur darstellung von perfluororganozinn- und -blei-verbindungen [1]

Perfluoroorgano tin and lead compounds can be prepared in high yields from the reactions of (CH₃)₃SnOCOCF₃ and (CH₃)₃Pb(OCOCF₃) with perfluoroorgano cadmium complexes. (CH₃)₃SiOCOCF₃ reacts with (CF₃)₂Cd complexes — probably via the intermediate (CH₃)₃SiCF₃ and CF₂ elimination — to form (CH₃)₃SiF and CF₃CdOCOCF₃ complexes. While the reaction of (CF₃)₂Cd·D with (CH₃)₃SnONO₂ yields CF₃NO as the only volatile product, (R_f)₂Cd·D (R_f  C₂F₅, iC₃F₇) forms R_fCdONO₂·D and (CH₃)₃SnR_f. The preparations and properties of the partly new compounds as well as the n.m.r. spectra are described.     

Equational partiality

A special kind of partiality of heterogeneous algebraic structures is introduced. Every operator of a heterogeneous operator domain is associated with a set of term equations as necessary and sufficient domain condition.It is shown that some kind of hierarchy condition for the system of domain equations is equivalent to the condition that every injective weak homomorphism is a strong homomorphism which is equivalent to the statement that every bijective weak homomorphism is an isomorphism.On the base of this result the notions of a quasi-variety and of a variety of equationally partial heterogeneous algebras are suggested. The class of all small categories becomes a standard example of a variety of equational partial heterogeneous algebras.Presented by V. Trnková.