IR spectroscopic study of the reactivity of aromatic 5-acyltetrazoloisoindoles

An IR study of the 5-acyl tetrazoloisoindoles solvent sensitive bands permit to assign the bands associated to the valence mode of the CO bond in the 1700-1500 cm⁻¹ area. This provides an explanation of the unusual stability of these newly synthesised compounds. Moreover, in air exposed solutions we observe the formation of unique degradation products. A mechanism for their formation and their probable structure was proposed with the help of IR spectroscopy.     

Electroweak radiative corrections toe + e −→γZ 0

We calculated the explicit analytic expressions for the electroweak radiative corrections to the differential cross sectione ⁺ e ^?→γZ ⁰ to one-loop in the framework of the Glashow-Salam-Weinberg model. Special attention is payed to the dependence on the Higgs and top quark masses.     

Notes on the lateral contraction of linear isotropic visco-elastic materials

Summary Visco-elastic materials can be investigated using creep experiments or stress relaxation experiments. In both experimental types of the phenomenon called lateral contraction occurs. Because the two types are known to be different, we need to distinguish two material functions to describe lateral contraction, namely a creep contraction ratio and a stress relaxation contraction ratio. Expressions are derived that describe how for linear and isotropic visco-elastic materials these functions depend on other material functions. It is demonstrated that these two possible contraction ratios are different functions. The contraction ratio based on the stress relaxation experiment is found to be the visco-elastic analogue of the clastic constant called Poisson's ratio.

---

Querkontraktion von isotropen, linear viskoelastischen Materialien

Übersicht Bei der Untersuchung von viskoelastischen Materialien kann man zwischen zwei Versuchsarten wählen, Kriechversuchen und solchen vom Typ Spannungsrelaxation. Weil in beiden Versuchsarten Querdehnung auftritt und weil außerdem beide Versuchsarten bekanntlich verschieden sind, muß man zur Beschreibung der Querdehnungseigenschaften auch zwei Materialfunktionen unterscheiden. Die eine beschreibt Querkontraktion, wenn das Material kriecht, während die andere die Querkontraktion des Materials im Falle eines Spannungsrelaxationsversuches erfaßt. Für isotrope, linear viskoelastische Materialien wird abgeleitet, wie diese Funktionen von anderen Materialfunktionen abhängen. Es wird gezeigt, daß die zwei Materialfunktionen tatsächlich verschieden sind. Außerdem findet man, daß die Querkontraktion in Spannungsrelaxationsversuchen als das viskoelastische Analogon der Poisson-Zahl anzusehen ist.

     

On convergence rates of suprema

Summary It is shown that the convergence rate of suprema of stationary Gaussian and related processes, such as processes defined by the empirical distribution function, is logarithmically slow, even if the rates are to be uniform over as few as three points. It is proved that the bootstrap approximation provides a substantial improvement.     

Kinetics of orientation of a side-chain liquid–crystal polymer as measured by a high-temperature SQUID-magnetometer

A superconducting quantum interference device (SQUID) magnetometer suitable for measurements of the magnetic susceptibility up to 600 K has been used to follow the kinetics of realignment in the nematic phase of a side-chain liquid–crystal polymer. Experiments are performed using monodomain and polydomain samples. Results obtained in monodomain samples are in quantitative agreement with the prediction of the continuum theory up to an angle of approximately 60°. Experiments conducted at higher starting angles give clear indication of backflow effects. Data obtained from experiments on polydomain samples have been compared with model calculations using the data on the monodomain samples. This comparison leads to the conclusion that in this case backflow effects play an important role, too. All results show that SQUID magnetometry allows monitoring of the kinetics of realignment with highest precision. © 1992 John Wiley & Sons, Inc.