Untersuchung von Mehl und Getreide

Ohne Zusammenfassung     

A computer-based spectrophotometric study of the kinetics of the aquation of halogenopentammine-chromium(III) perchlorate

Conventional determinations of rate constants k from absorption spectra employ a few selected wavelengths: by digitizing the complete spectrum computer calculations of k can be made at most wavelengths, and hence with better precision. This has here been satisfactorily tested for the aquation of halogenopentamminechromium(III) perchlorate. Two independent procedures are described, which are approximately equally onerous on computer time. Additionally, these procedures are shown to yield identical computer-generated spectra for the halogeno-complex before aquation commences, and accurate time infinity spectra, of the aquo-complex, for long half-life reactions. They also efficiently eliminate the effects of spectrophotometer instability over long periods of time.     

The order parameter in a spin glass

Various possible precise definitions of an Edwards-Anderson type of order parameter for an Ising model spin glass are considered, using boundary conditions for a finite system, states of an infinite system, and a duplicate-system approach. Several of these definitions are shown to yield identical results.     

A synchrotron radiation study of the electronic and geometric structure of CO on Pt{110}

Using both synchrotron and HeII radiation the electronic and geometric structure of Pt{110}-(2×1)p1g1 CO was examined. The shape resonance for the 4σ orbital of CO is found to be peaked at 38 eV, while that for the 5σ orbital is peaked at 28 eV. No shape resonance is observed from the 1π orbital. The $\text{5σ}\text{1π}$ ordering is reversed from that of gas phase CO. Further evidence, from the polar intensity variation of the non-bonding 4σ orbital, is presented for the tilted CO structure proposed previously.     

Lattice-gas model of multiple layer adsorption

The phase diagram for a lattice-gas model of physical adsorption on a homogeneous substrate has been calculated in a mean-field approximation. The first-order phase transitions corresponding to the addition of successive layers terminate in individual critical points as the temperature increases. The critical temperatures of successive layers increase, monotonically with layer number, from the critical temperature of the two-dimensional lattice gas to that of the bulk three-dimensional lattice gas. This last feature is probably an artifact of the mean-field approximation.     

Optical-model analysis of elastic scattering of 53.4 MeV helions from Fe

Elastic helion scattering from ⁵⁶Fe at 53.4 MeV was measured over the angular range 12° to 150°. Using the regular optical model, real-potential ambiguities, the shape of the imaginary term and the need for a spin-orbit term were explored. Coupled-channels (SCA) calculations based on the ground state and principal 2⁺ and 3⁻ states indicate that such coupling effects are not as dominant as the inclusion of a spin-orbit potential in the regular optical model. Previously reported helion scattering from ⁵⁹Co and ⁶⁰Ni at 50.1 MeV has been included in an average parameter analysis to generalise the improvements in the helion optical-model parameterization in this energy region.     

A contribution to the Rainich theory of the neutrino field

The neutrino-gravitational field is divided into fourteen distinct classes. This classification is shown also to determine the class of the space-time. Then for four particular classes of space-time, necessary and sufficient conditions on the concomitants of the Ricci tensor are given for it to admit a neutrino field. It is further shown that for three of these classes the neutrino field is determined uniquely by the metric of space-time.