On-shell improved lattice gauge theories

By means of a spectrum conserving transformation, we show that one of the 3 coefficients in Symanzik's improved action can be chosen freely, if only spectral quantities (masses of stable particles, heavy quark potential etc.) are to be improved. In perturbation theory, the other 2 coefficients are however completely determined and their values are obtained to lowest order.Heisenberg foundation fellow     

Substituent effects of phthalimide‐based nucleoside analogs on binding a CG Watson–Crick base pair

Five differently substituted phthalimide nucleosides were studied by NMR spectroscopic techniques for their ability to recognize and bind a cytosine–guanosine (CG) Watson–Crick base pair in CD₂Cl₂. Whereas only rather weak binding was observed for analogs with an amino, acetamido, or benzamido substituent, strong binding was observed with the analogs carrying an ureido and n‐butyl ureido residue. 2D NOE measurements at low temperatures confirm the proposed binding mode for the high‐affinity ligands but indicate binding interactions for the weakly bound analogs different from the expected geometry. Copyright © 2007 John Wiley & Sons, Ltd.     

Critical strength for ideal incommensurate structures

A concise method is developed to show the following in one dimension: (a) If there is a sharp metal-insulator transition in an ideal sinusoidal incommensurate structure then $\text{W}\text{V = 2}$. (b) There is an infinite dc conductivity of electrons in an ideal incommensurate structure for T = 0 if $\text{W}\text{V < 2}$. (c) Addition of impurities which scatter between all pairs of k values may lead to a finite conductivity for $\text{W}\text{V < 2}$. (It tends to zero as L → ∞). The concept of duality used by Aubry is then extended to the general problem of localization and the breakdown of extended states is illustrated.     

Cesàro Summability of Two-dimensional Walsh-Fourier Series

We introduce p-quasi-local operators and the two-dimensional
dyadic Hardy spaces defined by the dyadic squares. It is proved that, if a sublinear operator is p-quasi-local and bounded from to , then it is also bounded from to . As an application it is shown that the maximal operator of the Cesàro means of a martingale is bounded from to and is of weak type (1,1) provided that the supremum in the maximal operator is taken over a positive cone. So we obtain the dyadic analogue of a summability result with respect to two-dimensional trigonometric Fourier series due to Marcinkievicz and Zygmund; more exactly, the Cesàro means of a function converge a.e. to the function in question, provided again that the limit is taken over a positive cone. Finally, it is verified that if we take the supremum in a cone, but for two-powers, only, then the maximal operator of the Cesàro means is bounded from to for every .

     

Martingale Hardy spaces,BMO and VMO spaces with nonlinearly ordered stochastic basis

VMO. , ⁺, «» VMO . « » .     

Halbquantitative Isotopenverdünnungsanalyse im Mikro- und Submikrogrammbereich mit Hilfe der Ringofenmethode

Zusammenfassung Ein halbquantitatives Analysenverfahren wird beschrieben, das im wesentlichen eine Kombination der Isotopenverdünnungsanalyse mit der Ringofentechnik ist: Zu der Probelösung eines Ions (xg) wird eine stets gleiche Menge (a g) des gleichen Ions in radioaktiv markierter Form zugesetzt. Mit einem geeigneten Fällungsreagens wird ein Anteil (b g) vonx +a ausgefällt und auf einem Rundfilter mit Hilfe der Ringofenmethode abgetrennt. Die den Anteilenb undx + a – b entsprechenden Zählraten werden bestimmt. Die Auswertung der Meßergebnisse erfolgt graphisch mit Hilfe einer Eichkurve.Am Beispiel der Bestimmung von Ca²⁺, PO₄ ^3– und Fe³⁺ wird die Methode erläutert. Mengen von einigen Zehntel bis zu einigen Mikrogramm der genannten Ionen können ausreichend genau bestimmt werden.

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Summary A semiquantitative analytical procedure is described that essentially is a combination of the isotope dilution analysis with the ring oven technique. To the test solution of an ion (x g) there is added an always constant amount (a g) of the. same ion in radioactive labelled form. A portion (b g) ofx +a is precipitated with a suitable precipitant and collected on a circular filter with the aid of the ring oven method. The counter rates corresponding to the portionsb andx + a – b are determined. The evaluation of the data is made by a graphic method with the aid of a standard curve.The method is discussed using as example the determination of Ca²⁺, PO₄ ^3–, and Fe³⁺. Amounts ranging from several tenths to several micrograms of these ions can be determined with adequate accuracy.

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Résumé On décrit un procédé d'analyse semiquantitative combinant principalement l'analyse par dilution isotopique avec la technique du four annulaire. On ajoute à la solution contenant l'ion à analyser (x g) une quantité toujours égale (a g) du même ion sous forme marquée radioactive. A l'aide d'un réactif précipitant approprié, on précipite une partie (b g) dex +a et l'on effectue la séparation sur un filtre rond par la méthode du four annulaire. On détermine les valeurs correspondant aux partiesb etx +a – b. En utilisant une courbe d'étalonnage, on effectue graphiquement le calcul des résultats des mesures.On explique la méthode en prenant l'exemple du dosage de Ca²⁺, PO₄ ^3– et Fe³⁺. On a pu doser avec suffisamment de précision des quantités allant de quelques dixièmes de microgrammes d'ions connus à quelques microgrammes.

     

Papierchromatographische Trennung und quantitative Bestimmung von Benzo(a)pyren und Benzo(k)fluoranthen in Schwebstoffen

Zusammenfassung Die Leistungsfähigkeit des papierchromatographischen Verfahrens von Wieland und Kracht zur Trennung von Benzo(a)pyren und Benzo(k)fluoranthen wurde an synthetischen Gemischen und Schwebstoffextrakten untersucht, da die Fluoreszenzspektren sowie die Eigenschaften dieser Substanzen sehr ähnlich sind. Die Meßergebnisse zeigen, daß eine einwandfreie Trennung der beiden Substanzen voneinander sowie darüber hinaus von anderen fluoreszierenden Anteilen der Schwebstoffextrakte gelingt. Die Wiederauffindungsrate bei Versuchen mit internem Standard liegt je nach Konzentrationsbereich zwischen 86 und 103%. Das wenig aufwendige Verfahren erscheint damit sowohl zur Bestimmung von Benzo(a)pyren als auch Benzo(k)fluoranthen in der Atmosphäre geeignet.

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Paper chromatographic separation and quantitative determination of benzo(a)pyrene and benzo(k)fluoranthene in suspended material

Summary The effectiveness of the paper Chromatographic procedure of Wieland and Kracht for separation of benzo(a)pyrene and benzo(k)fluoranthene was investigated on synthetic mixtures and extracts of suspensions since the fluorescence spectra and the properties of these substances are very similar. The results of measurements show that an impeccable separation of the two substances from each other as well as from other fluorescing components of the suspension extract is possible. In trials with internal standard the recovery rate was between 86 and 103% depending on the concentration. The procedure is inexpensive and is thus suitable for determination of benzo(a)pyrene and benzo(k)fluoranthene in the atmosphere.

     

Hexamethylphosphorsäuretriamid als Ligand, 3. Mitt.: Umsetzungen von [Co(HMPT)4]2+ mit Rhodanid-, Cyanid- und Azidionen

Zusammenfassung Auf Grund spektrophotometrischer, potentiometrischer und konduktometrischer Befunde entstehen aus [Co(HMPT)₄]²⁺ in Hexamethylphosphorsäuretriamid (HMPT) bei Zusatz von Pseudohalogenidionen folgende Koordinationsformen: [Co(HMPT)₃N₃]⁺, [Co(HMPT)₂(N₃)₂], [Co(HMPT)(N₃)₃]^–, [Co(N₃)₄]^2–, [Co(HMPT)₃NCS]⁺, [Co(HMPT)₂(NCS)₂], [Co(HMPT)(NCS)₃]^–, [Co(NCS)₄]^2–, [Co(HMPT)₂(CN)₂], [Co(HMPT)(CN)₃]^–, [Co(HMPT)(CN)₅]^3–.

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Hexamethyl phosphoric triamide as a ligand, III: Reactions of [Co(HMPT)₄]²⁺ with rhodanide, cyanide, and azide ions, resp

Spectrophotometric, potentiometric and conductometric results indicate that addition of pseudohalide ions to [Co(HMPT)₄]²⁺ in hexamethylphosphoramide (HMPT) leads to the following coordination forms: [Co(HMPT)₃N₃]⁺, [Co(HMPT)₂(N₃)₂], [Co(HMPT)(N₃)₃]^–, [Co(N₃)₄]^2–, [Co(HMPT)₃NCS]⁺, [Co(HMPT)₂(NCS)₂], [Co(HMPT)(NCS)₃]^–, [Co(NCS)₄]^2–, [Co(HMPT)₂(CN)₂], [Co(HMPT)(CN)₃]^–, [Co(HMPT)(CN)₅]^3–.

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Mit 7 Abbildungen

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2. Mitt.:V. Gutmann undA. Weisz, Mh. Chem.100, 2104 (1969).     

Effect of Light on the Electrokinetic Behavior of TiO(2) Particles in Contact with Cr(VI) Aqueous Solutions

The electrokinetic behavior of titanium dioxide particles (Degussa P25, mainly composed of anatase) put in contact with chromium(VI) aqueous solutions is highly sensitive to light exposure under normal laboratory conditions. In the dark, adsorption of Cr(VI) gives rise to substantial decrements in the mobilities, especially in the acidic branch, and, at higher concentrations, to shifts in the isoelectric point (pH(piep)) to lower values, as expected for anionic chemisorption. A two-mode adsorption model accounts qualitatively for the results. Under light, pH(piep) shifts in the opposite direction as the Cr(VI) concentration increases. A maximum value is attained at [Cr(VI)] approximately 10(-3) mol dm(-3), pH(piep) 8.2, which coincides with values reported for hydrous chromium(III) oxides. At higher concentrations, Cr(VI) adsorption defines a shift of pH(piep) to lower values. It is concluded that light absorption by titanium dioxide promotes the reduction of Cr(VI) and the surface precipitation of the hydrous Cr(III) oxide. The values of pH(piep) for partially covered surfaces are well described by a simple model of surface ionization derived earlier. FTIR/ATR analysis of the surfaces supports this interpretation, and further suggests that one of the modes of Cr(VI) adsorption implies surface dimerization to yield adsorbed dichromate. Copyright 2000 Academic Press.