Abstract: A single-crystal rod, obtained using CZ crucible pulling, has a crystal cone and a cylindrical single-crystal rod, and the crystal cone has an apex angle of 30° to 90°. There is also a process for producing dislocation-free single-crystal rods using CZ crucible pulling in which a seed crystal is immersed in a melt and is pulled out again, and a cone with an apex angle of from 30° to 90° is pulled.

Abstract: Close-coupled atomization methods employing non-axisymmetric fluid flow geometries have demonstrated superior efficiency in the production of fine superalloy powder, such as, for example, nickel base superalloys compared to conventional close-coupled atomization utilizing an axisymmetric gas orifice and an axisymmetric melt nozzle. It is believed that the principal physical mechanisms leading to non-axisymmetric atomization system fine powder yield improvement are atomization plume spreading, the at least lessening of the melt pinch down at the interaction point between the atomization liquid and the liquid melt and improved melt film formation at the melt guide tube tip. The greatest fine powder yield improvement occurred when the non-axisymmetric atomization systems are operated with atomization parameters that result in the formation of multiple atomization plumes.

Abstract: Purple membrane preparations having an increased holographic diffraction efficiency. The purple membrane preparations have a diffraction efficiency of less than 5 seconds and a resolution of greater than 1,500 lines/mm. The purple membrane preparations are obtainable by adjusting a purple membrane suspension having a photocycle time of at least 10 ms to a pH of between 6 and 11 by means of a buffer, adding from 1% to 10% by weight of a proton donor to this purple membrane suspension, and drying the resultant suspension down to a water content of from 1% to 30% by weight.

Abstract: The invention relates to optical elements based on liquid-crystalline substances, and to a process for the production thereof. The optical elements based on liquid-crystalline substances are ones which exhibit no birefringence in a defined direction of incidence, optical elements in which no birefringence occurs perpendicularly to the surface being excepted. The process for preparing the optical elements comprises illuminating a liquid-crystalline substance with unpolarized light of suitable wavelength at a defined angle in such a way that, after illumination, the director of this substance is aligned parallel to the direction of the illuminating light on passing through said substance.

Abstract: The invention relates to optical elements based on helical liquid-crystalline substances, having reflection bands of linear-polarized light, and to a process for preparing the same. The optical elements of this invention contain only one optically effective component based on helical liquid-crystalline substances. They reflect light incident perpendicular to the surface in a linear-polarized manner parallel to the direction of incidence of the incident light. The process for preparing the optical elements comprises illuminating a helical liquid-crystalline substance which contains at least one photoisomerizable substance with linear-polarized light in such a manner that this substance is subsequently aligned so that it exhibits at least one reflection band of linear-polarized light on illumination. Suitable helical liquid-crystalline substances are in particular organopolysiloxanes. The optical elements are suitable, for example, for data storage.

Abstract: The invention relates to cholesteric organic polymers which contain, in the side groups, both mesogens, at least some of which are optically active, and chromophoric groups.