α-Chlor-nitrone II: Eine Methode zur Darstellung von γ-Lactonen aus Olefinen. Über synthetische Methoden, 6. (vorläufige) Mitteilung

The addition products obtained by the Ag⁺-induced reaction of α-chloro-aldonitrones with olefins (see preceding communication) can be utilized efficiently for making γ-lactones (see scheme 1).     

Spektralphotometrische Bestimmung von Eisen(III) und Chrom(VI) mit Helasolviolett 4R

Ohne Zusammenfassung

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Spectrophotometric determination of iron(III) and chromium(VI) by means of helasol violet 4R

     

Variants of recognition problems for modular forms

We consider the problem of distinguishing two modular forms, or two elliptic curves, by looking at the coefficients of their L-functions for small primes (compared to their conductor). Using analytic methods based on large-sieve type inequalities we give various upper bounds on the number of forms having the first few coefficients equal to those of a fixed one. In addition, we consider similar questions of recognizing symmetric squares and CM forms from the behavior of small primes.Received: 30 August 2004     

Molar excess enthalpies and volumes of mixtures of 2,4,6-trimethyl-pyridine with some aliphatic alcohols

The relationship enthalpy of mixing and excess molar volume of mixing versus composition were studied at 313.15 K for binary systems of 2,4,6-collidine with normal aliphatic alcohols. It was found that at this temperature the values ofH ^E andV ^E are negative and change with the length of the alkyl group of the alcohol.     

Chromatographic and spectroscopic investigations of the oxidation process in methyl oleate and methyl elaidate

In our paper the studies on the initial stage of autoxidation of cis- and trans-9-octadecenoic acid methyl esters were reported. The applied analytical methods were: (1) high-resolution NMR spectroscopy; (2) absorption iR spectroscopy; (3) adsorption TLC. The complementary methods were: determination of peroxide number, acid number and iodine number in the course of autoxidation. Our results pointed to the fact that the oxidation of trans-isomer showed the more restrained character. We tried to suggest the influence of structure of the examined compounds and of the peroxides formed in the initial stage of autoxidation on the course of this process.     

Lifetimes andg J factors of 6s7p and 5d6p levels of Ba I

Excited states of Ba have been investigated with optical double resonance and Hanle effect. The followingg _J factors and natural lifetimes (in 10^?9 sec) have been measured $$\begin{gathered} 6s7p\left\{ {\begin{array}{*{20}c} {^1 P_1 :g_J = 1.003(2)\tau = 13.5(6)} \\ {^3 P_1 :g_J = 1.4971(8)\tau = 85.0(8.0)} \\ \end{array} } \right. \hfill \\ 5d6p\left\{ {\begin{array}{*{20}c} {^1 P_1 :g_J = 1.004(2)\tau = 12.4(9)} \\ {^3 P_1 :g_J = 1.4847(15)\tau = 11.7(9)} \\ {^3 D_1 :g_J = 0.5064(3)\tau = 17.0(5).} \\ \end{array} } \right. \hfill \\ \end{gathered}$$ g _J is utilized to test the mixing coefficients of the wave functions in the intermediate coupling model. The lifetimes are converted into absolute transition probabilities for all the decays originating from the states investigated under the assumption that their branching ratios obtained elsewhere are correct. This assumption is not unquestionable, however.     

Interference of secondary pions and time-space characteristics of their emission volume in π− p interactions at 40 GeV/c

The interference of positive and negative pions produced in π^? p interactions at 40 GeV/c is studied. It is shown that negative pions are emitted from larger distance than positive ones. The influence of resonance production on the size of pion emission volume is observed.     

An extension of the multivariate component-resolution method to three components

The extension of the multivariate curve resolution theory presented is based on the minimum assumptions of non-negativity of sensor responses and non-negativity of quantities of components, as given by Lawton and Sylvestre. The theory is explicitly given for three components, while the algorithms developed may potentially be extended to the more general n-component case. The analytical solution to the problem of defining the physically permitted regions for the sensor responses (“spectra”) or quantity profiles of pure components is given. Implementations of the algorithms developed are used for finding the permitted ranges of the pure component spectra from mixture spectra. Extensions of the minimal assumption theory are suggested.