Enhancement of oxygen surface exchange kinetics of SrTiO(3) by alkaline earth metal oxides

The oxygen incorporation reaction in undoped SrTiO(3) was investigated by electrical measurements (pressure modulation technique) in the temperature range from 650-920 degrees C and by means of tracer exchange experiments in the temperature range from 458-600 degrees C. The surface of the undoped SrTiO(3) single crystals was modified by alkaline earth metal compounds leading to a tremendous enhancement of the effective surface exchange rate for oxygen incorporation as compared to the uncoated surface.     

A fast solver for the gyrokinetic field equation with adiabatic electrons

Describing turbulence and microinstabilities in fusion devices is often modelled with the gyrokinetic equation. During the time evolution of the distribution function a field equation for the electrostatic potential needs to be solved. In the case of adiabatic electrons it contains a flux-surface-average term resulting in an integro-differential equation. Its numerical solution is time and memory intensive for three-dimensional configurations. Here a new algorithm is presented which only requires the numerical inversion of a simpler differential operator and a subsequent addition of a correction term. This new procedure is as fast as solving the equation without the surface average.     

Effect of protonation on the conformation of cinchonidine

The protonation of cinchona alkaloids in solution leads to the severe restriction of their internal rotational degrees of freedom and to the locking of the molecule around a specific conformation held in place by a bridging counterion of the acid used for protonation. For HF, direct interactions were detected by NMR between the fluorine anion and not only with the acidic hydroxo group but also with non-acidic hydrogen atoms in the quinoline ring.     

Double matrix membranes for potentiometric cation selective disposable sensors

The construction of double matrix membranes (DMM) for disposable NH ₄ ⁺ , Na⁺ and pH sensors is described. The usual polymer matrix membrane was incorporated in an inert micro fibre matrix (MFM). Capillary forces distribute the cocktail homogeneously in the MFM; this also determines the thickness. Sensors using the new DMM have shown selectivity, detection limits and slope comparable with polymer matrix membranes. The advantages of DMMs are their mechanical stability, the feasibility of low cost mass production with identical parameters and improved handling.