Quantitative electron probe microanalysis for the characterization of thin carbon-boron layers in fusion devices

Summary The first wall of the fusion device TEXTOR at the Forschungszentrum Jülich has been coated in situ with an amorphous hydrogen rich carbon/boron film (a-C/B:H) which reduces plasma impurities caused by the plasma surface interaction. The results of the coating process of the 35 m² large inner wall surface have been controlled by a recently developed modification of the quantitative electron probe microanalysis, which has been applied to 12 samples from specified positions inside the tokamak. The quantification itself is based on a Monte Carlo simulation of electron trajectories providing very accurate results for X-ray intensities emitted by elements present in the electron bombarded sample. The Monte Carlo results are used in the present work to calibrate the measured X-ray intensities emitted by boron and carbon from the a-C/B:H layers deposited on pure silicon substrates. As a result the total deposited mass of the layer per area unit as well as the composition of the layers (except hydrogen) could be determined very accurately. The relative errors were less than 7%. The limit of detectability were found to be in the range of one monolayer for boron as well as for carbon.     

Synthesis of coumarins by ring-closing metathesis using Grubbs’ catalyst

A novel generally applicable synthesis of coumarins from phenolic substrates utilizing ring-closing metathesis is described. This sequence involves O-allylation of phenols followed by ortho-Claisen rearrangement, subsequent based-induced isomerization affording 2-(1-propenyl)phenols, acylation with acryloyl chloride, and finally ring-closing metathesis (RCM) with Grubbs’ second generation catalyst.     

Correlating second harmonic optical responses of single Ag nanoparticles with morphology

Femtosecond laser excited second harmonic (SH) activity from single Ag nanoparticles is reported. A correlation of SH single-particle measurements with high-resolution imaging of particle morphology by TEM was achieved by creating position markers on an optical and electron transparent substrate (Si3N4 thin film, approximately 100 nm). We compared the SH activity of single Ag nanoparticles (nanospheres versus nanorods) and cluster structures (composed of two or multiple particles, e.g., dimers and trimers). The direct correlation of single-particle structures and SH activity, spectral and power dependence, strongly suggests one-photon resonant driven nonlinear oscillator response mechanism.     

Elektronenstruktur,Spektren und Magnetismus von Chinon-π-Komplexen des Nickels

Zusammenfassung Die Elektronenstrukturen von Bis-durochinon-nickel(0) und der Komplexe vom Typ Olefin-Ni(0)-Chinon werden im Rahmen der LCAO-MO-Näherung diskutiert und zur Deutung der Absorptionsspektren herangezogen. Den im freien Durochmon auftretenden Übergängen lassen sich in den Komplexspektren jeweils nur wenig verschobene Banden zuordnen. Darüber hinaus wird eine intensive Charge-Transfer-Bande beobachtet, die einem Übergang vom höchsten besetzten Nickelzustand zum tiefsten unbesetzten Chinon-Orbital entspricht. Aus der Intensität der Bande, die im freien Chinon dem b _3g 2b ₂ g-Übergang zugeordnet wird, ergibt sich für das gelöste Bis-durochinon-nickel(0)-Molekül die Symmetrie D _2h . Während die Komplexe mit Durochinon in Übereinstimmung mit der Theorie diamagnetisch sind, weisen die analogen Verbindungen der Dimethylchinone magnetische Momente von 1,52 bzw. 2,75 B. M. auf, woraus auf eine Mitbeteiligung polarer Strukturen am Grundzustand dieser Komplexe geschlossen wird.

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The electronic structures of bis-duroquinone-nickel(0) and complexes of the type olefine-Ni(0)-quinone are discussed in the MO-LCAO approximation and used for an interpretation of the absorption spectra. The transitions of the free duroquinone can be correlated with transitions of the complexes at nearly the same wavelengths. In addition, an intense charge transfer band is observed which corresponds to a transition from the highest occupied nickel orbital to the lowest unoccupied quinone orbital. From the intensity of the band which corresponds to b _3g 2b_2g in the free quinone, the symmetry D _2h for the dissolved bis-duroquinone-nickel(0) molecule is deduced. Whereas the duroquinone complexes are diamagnetic in agreement with theory, analogous compounds of the diméthylquinones exhibit magnetic momenta of 1.52 and 2.75 B. M. suggesting the participation of polar structures in the ground state of these complexes.

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Résumé Les structures électroniques du bis-duroquinone-nickel(0) et des complexes du type oléfine-Ni(0)-quinone sont discutées dans le cadre del'approximationMO-LCAO et utilisées pour l'interprétation des spectres d'absorption. Aux transitions de la duroquinone libre peuvent être attribuées des bandes peu déplacées dans les spectres des complexes. En outre on observe une bande intense correspondant à une transition de la plus haute orbitale occupée du nickel à la plus basse orbitale libre de la quinone. L'intensité de la bande nommée b _3g 2b _2g dans la quinone libre indique la symétrie D _2h pour la molécule dissoute du bis-duroquinone-nickel(0). Tandis que les complexes de la duroquinone sont diamagnétiques en accord avec la théorie, des composés analogues des diméthylquinones présentent des moments magnétiques de 1,52 et de 2,75 B. M. d'où l'on infère la participation de structures polaires à l'état fondamental de ces complexes.

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6. Mitteilung über Komplexe vom Typ des Bis-durochinon-nickel(0). 5. Mitt. vgl. [11].     

UV-VIS and CD-spectroscopic investigations of intermolecular interactions of bile pigments with small proteins

Summary The intermolecular complex formation of bilirubin and biliverdin with two proteins (basic pancreatic trypsin inhibitor and lysozyme) were studied by optical and chiroptical methods. Evidence for specific intermolecular interactions of biliverdin with both proteins was found. Bilirubin forms a soluble complex only with lysozyme.

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UV-VIS und CD-spektroskopische Untersuchungen intermolekularer Wechselwirkungen von Gallenpigmenten mit kleinen Proteinen

Zusammenfassung Die intermolekulare Komplexbildung von Bilirubin und Biliverdin mit zwei Proteinen (basischer pankreatischer Trypsininhibitor und Lysozym) wurden mittels optischer und chiroptischer Spektroskopie untersucht. Für Biliverdin konnten intermolekulare Wechselwirkungen mit beiden Proteinen nachgewiesen werden. Bilirubin bildet nur mit Lysozym einen löslichen Komplex.

     

Ultra trace analysis of refractory metals by solid state mass spectrometry — A comparison of GDMS,SSMS and SIMS

The analytical performance of a glow discharge quadrupole mass spectrometer is demonstrated using sintered tungsten as an example. The inherent problem of molecular interferences in glow discharge mass Spectrometry has been considerably reduced using neon as a complementing discharge gas. Particular attention has been paid to time dependences. Analytical figures of merit are presented.     

Amorphe Potenzen kompakter Räume

A set is amorphous, if it is not a union of two disjoint infinite subsets. The following variants of the Tychonoff product theorem are investigated in the hierarchy of weak choice principles. TA1: An amorphous power of a compactT ₂ space is compact. TA2: An amorphous power of a compactT ₂ space which as a set is wellorderable is compact. In ZF⁰TA1 is equivalent to the assertion, that amorphous sets are finite. RT is Ramsey's theorem, that every finite colouring of the set ofn-element subsets of an infinite set has an infinite homogeneous subset and PW is Rubin's axiom, that the power set of an ordinal is wellorderable. In ZF⁰RT+PW implies TA2. Since RT+PW is compatible with the existence of infinite amorphous sets, TA2 does not imply TA1 in ZF⁰. But TA2 cannot be proved in ZF⁰ alone. As an application, we prove a theorem of Stone, using a weak wellordering axiomD ₃ (a set is wellorderable, if each of its infinite subsets is structured) together with RT.

Diese Arbeit ist Teil der Habilitationsschrift des Verfassers im Fachgebiet Mathematische Analysis an der Technischen Universität Wien.     

Regularisierte Faltung von Distributionen. Teil 1: Zur Berechnung von Fundamentallösungen

Zusammenfassung Für 2 Distributionen, deren Faltung nicht existiert, wird—mehrdeutig—eine bezüglich eines Differentialoperators regularisierte Faltung definiert.An 4 Beispielen wird die Anwendbarkeit der regularisierten Faltung bei der Berechnung von Fundamentallösungen faktorisierbarer Differentialoperatoren gezeigt. Dabei wurde die Fundamentallösung in Beispiel 3.2. erstmalig ohne Überlegungen physikalischer Art hergeleitet. Beispiel 3.3. verallgemeinert bekannte Ergebnisse, wobei diese als Spezialfälle erscheinen (Bemerkung 3) oder als fehlerhaft nachgewiesen werden (Bemerkung 4). Die Fundamentallösungen der Beispiele 3.1 und 3.4 scheinen in dieser Form neu zu sein.Schließlich folgen einige einfache Sätze, mittels derer Fundamentallösungen von iterierten Differentialoperatoren angegeben werden können. Sie werden im 2. Teil der Arbeit (Eine Tabelle von Fundamentallösungen) angewendet. Literaturhinweise finden sich am Ende von Teil 2.

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Summary For two distributions (whose convolution does not necessarily exist) we define a (manyvalued) convolution regularized with respect to a differential operator.We illustrate by four examples the usefulness of the concept of a regularized convolution for computing fundamental solutions of factorisable differential operators. The fundamental solution of example 3.2 is derived for the first time without considerations from physics. Example 3.3 generalizes well-known results, which either appear as special cases (remark 3) or are proved to contain errors (remark 4). The fundamental solutions of examples 3.1 and 3.4 seem to be new in this form.Finally we give some simple propositions concerning fundamental solutions of iterated differential operators. They will be used in part 2 of this paper (a table of fundamental solutions)The references are given at the end of part 2.

     

Optimization of an electrolytic conductivity detector for determination of toxic nitrogen-containing food contaminants separated by open tubular column gas chromatography

The combination of open tubular column gas chromatography with electrolytic conductivity detection has been evaluated for the determination of nitrogen-containing pesticide residues in food extracts. Optimization of the column position at the column-detector interface was crucial to the successful operation of the detector. The signal-to-noise ratio and response stability of the detector are greatly influenced by the composition of the electrolyte solvent. Large volume splitless injections using retention gaps and optimized detector operating conditions enabled pesticide residues in food extracts to be determined at sub parts-per-million levels. Although the electrolytic conductivity detector is less sensitive than the thermionic ionization detector, its greater nitrogen selectivity can he crucial to the determination of nitrogen-containing contaminants in food extracts, particularly in complex mixtures where phosphorus-containing contaminants or matrix compounds are also present.