A light-scattering photometer for use at elevated pressures

A new light scattering photometer has been designed in order to perform light-scattering measurements at various temperatures and under pressures of 1–1000 atm. Since the scattering angle is constant (90°C), the dimensions of the dissolved molecules are determined by measuring the intensity at different wavelengths. The method of measurement, the calibration of the instrument, and the treatment of data are described. By a series of test measurements on polystyrene in trans-decalin solutions it is shown that one obtains reliable results and finds considerable effects of pressure on the radius of gyration and the fundamental thermodynamic properties of the system.     

Photoproduction ofK + Λ andK +*∑0 from hydrogen between 1.3 and 1.45 GeV

It will be shown that the perturbation theory approach with respect to the amplitude of the roughness for the scattering of light by rough surfaces is equivalent to a model consisting of a smooth surface and surface current sources. This model has an obvious physical meaning and allows a simple calculation of the scattered fields, which are given. The model and the previous one given by Stern are identical up to the position of the surface currents, which have to be placed into the vacuum. Consequently the former explanation has to be corrected, which says that the peak of the scattered radiation at the plasma frequency is generated by surface roughness. We will show that it is possible to generate this maximum by statistical inhomogenities within the metal.     

Deep levels of iron implanted inn-type silicon

Results of an investigation of 19 organic dyes pumped by a 1.7 MW discharge-pumped XeCl excimer laser are reported. The dye-laser emission covered a wide wavelength range from 340 nm to 710 nm.P-terphenyl shows efficient laser action. The highest energy conversion efficiency exceeds 40% in visible region. In comparison with 250 kW nitrogen laser pumping, higher efficiencies are obtained for most of these dyes in the same dye-laser configuration.     

Superconductivity and processing of single Bi−O layered cuprates in the (Bi,Pb)−Sr−(Ca,Y)−Cu−O system

The effects of improved materials processing on single Bi–O layered cuprates in the (Bi, Pb)–Sr–(Ca, Y)–Cu–O system have been investigatged. For Bi-1212 we have improvedT _c to 102 K. The bulk nature of superconductivity is confirmed by the presence of superconducting volume fractions ( ZFC) around 30–40%. The critical current density is 2×10⁶ Acm^–2 at 5 K and 0 T. Moreover, indications for the presence of a second phase probably Bi-1223 with a transition to superconductivity in the range of 115–150 K have been found.     

Studies on styrene phosphonic acid

Some properties of styrene phosphonic acid (SPA) were studied. The crystals were triclinic, witha=0.6434 nm,b=0.5842 nm,c=2.0338 nm, =96.17°, =97.33°, =79.65° andZ=4. SPA underwent a change in crystal structure at 78.8°C, the hydrocarbon network became disordered (liquid-like) at 138.5°C. Crystals melted at 148.6°C giving a cubic mesophase, then changed to an isotropic liquid at 155.6°C and at 162.13°C SPA underwent decomposition. Values for pK₁=2.15 and pK₂=7.66 were obtained at 25°C. The water solubility of SPA at several temperatures, and its interaction with surfactant micelles were determined.     

Scale-up of recombinant protein purification by hydrophobic interaction chromatography

The scale-up of hydrophobic interaction chromatography is described. Human recombinant superoxide dismutase was used as a model. The scale-up was performed by keeping the height to diameter (H/D) ratio of the column constant. The success of scale-up was evaluated by reversed-phase high-performance liquid chromatography of the eluted material. The wrong H/D ratio causes decreased resolution.