The influence of kinetics on the direct titration curves of natural water systems — theoretical considerations

The effect of rate of complex formation is calculated on the titration curves of natural waters with traces of metals. The effect can be distinguished from multiple complex formation.     

Self-consistent nonlocal potentials near planar surfaces

A new derivation of the self-consistent dynamically screened nonlocal Coulomb potential near a planar surface is presented, based on the integral equation approach. The exact solution is obtained without restrictions on the dynamical response of the solid (e.g. RPA in metals), the type of surface potential or electronic density profile, and without additional matching or boundary conditions. This makes the present approach particularly useful e.g. in the general discussion of model-independent screening phenomena at metal surfaces. The application to the calculation of matrix elements for electron and ion excitation of collective modes and electron-hole pairs is formulated, and the connection with the previous results discussed.     

The breakdown of scaling due to the possible structure of nucleonic constituents

Aside from relativistic quark model representations which correspond to the picture of point-like quarks, the current algebra also allows representations which can be interpreted in terms of quarks with structure. We speculate about the possibility that the experimentally observed small deviations from scaling for higher values of q² point out the extended nature of nucleon constituents.     

Dünnschicht-chromatographische Trennung der Phenole auf Stärke

By thin-layer chromatography on rize starch mixtures of phenol, pyrocatechol, resoroinol, hydroquinone and pyrogallol as well as chloro- and nitroderivatives of phenol were separated. By Martin's theoretical postulates for partition chromatography the R _M -values and group constants were calculated.     

Crystal and molecular structure of 17-β-methyllupanine perchlorate

The formula of the title compound is C₁₆H₂₇ClN₂O₅,MW = 362.9 orthorhombic,P2₁2₁2₁,a = 8.403(1),b= 13.133(1),c= 15.972(2) Å,Z = 4,D _x = 1.37 g cm^–3, (CuK) = 2.2 mm^-1. The lupanine skeleton has atrans-trans configuration. The ringA has a half-chair conformation, theB andD rings adopt a chair form, and theC ring forms a boat. The lupanine cations are linked together by the intermolecular hydrogen bonds forming infinite chains alongb. The N(16) ... O(C2) distance is 2.763(7) Å.     

Pairing vibrational states and the generator coordinate method

The pairing vibrational states and the two-neutron transfer cross sections between these states are calculated in Ni, Sn and Pb isotopes by the generator coordinate method (GCM). The particle number fluctuation of the BCS functions is handled by projecting in a good approximation on sharp particle numbers. The results agree quite well with the experimental data.     

A simple solution to the strongCP-problem

We suggest soft breaking of Peccei-Quinn symmetry as a simple solution to the strongCP problem without the presence of the axion. In the context of theSU(2) _L ×U(1) model, it is shown how settingθ _tree=0 keeps θ calculable and, furthermore, extremely small: θ?10^?16. Unlike in the case of the axion the model is free from the cosmological domain wall problem. Possible extension of this idea to grand unification is discussed.     

AgTh2(PO4)3 — A new case of the non-hydrogen bonded phosphate ferroelectric

The basic crystallographic data of AgTh₂(PO₄)₃ single crystals have been determined for the first time by means of X-ray diffraction methods. The crystals are monoclinic, space group isCc with four formula units per unit cell. The dimensions of the unit cell are:a=17·385 Å,b=6·815 Å,c=8·148 Å,β=101·10°. Using the Sawyer and Tower method it has been proved that the crystals possess ferroelectric properties. Performing the measurements at room temperature the values of spontaneous polarization and coercive field in the direction normal to (100) face have been determined.