Der Interferenzeffekt in der magnetischen Kernrelaxation für Vierspin-Systeme. V

The interference of intramolecular dipole-dipole interaction and anisotropy of electronic screening in nuclear magnetic relaxation is taken into account for systems containing four identical nuclei of spin 1/2 located at the corners of a tetrahedral, a square and a rectangle. The influence of spinrotational interaction is also considered. The results, presented in the paper show that, due to the interference effect, a significant deviation of a pure exponential time dependence of nuclear magnetization in some special cases may appear.     

Formfaktor des β-Spektrums von99Tc

The β-spectrum of the second non-unique forbidden 9/2⁺?5/2⁺ transition in the decay of⁹⁹Tc has been investigated with a 4π – Si (Li)-semiconductor-spectrometer. The shape factor has been determined: S(W)=k (1?3.97 W+1.15/W+3.05 W²). It was also possible to fit the data with the normal ξ-Approximation to the theoretical shape factorS(W)=k(q¹²+0.54 p²). The second forbidden 2⁺? 0⁺ β^?-transition in the decay of³⁶Cl was reinvestigated to test the spectrometer as well as the fitting-technique.     

Chemie-Nobelpreis für Ozonforscher

Der diesjähriege Nobelpreis für Chemie geht an Paul Crutzen vom Max-Planck-Institut für Chemie in Mainz, Mario Molina (Massachusetts Institute of Technology) und R. Sherwood Rowland (University of California, Irvine, USA). Das Komitee würdigte damit ihre ?Arbeiten zur Chemie der Atomsphäre, insbesondere über Bildung und Abbau von Ozon”?.     

Apodisation für die beugungsbegrenzte Abbildung des Achsenpunktes mit rotationssymmetrischen optischen Systemen

Apodization for Diffraction Limited Image of the Axial Point by Rotational Symmetric Optical Systems A pupil function is suggested where by considering apodization the diffractional integral is solvable in closed form. Apodization by bessel function produces higher intensity in the centre of the diffraction pattern and better resolution compared to apodization by gauss function.