Films of optical quality suitable for waveguide and optical device elements have been designed and growth processes developed for producing such films. Films with various compositions and thicknesses have been prepared by chemically depositing GaAs and Ga.. .AL As upon GaAlAs and GaAs. Film thicknesses from 2 to 17 urn and compositions from x = 0.02 to x = 0.25 (Ga. Al As) were obtained. Techni...

Transition to a superconducting zero-resistance state at 155 K is observed for the first time in bulk material. A new five-element compound has been synthesized with nominal composition YIBa2Cu3F20y. Fluorine plays a critical role in achieving this eAect. X-ray diffraction and electron microprobe analysis indicate that the samples are multiphasic. Evidence is presented that the samples contain ...

The effects of different doses of Ukrain and/or strontium on the rat teeth intertubular dentine were analysed in cuts perpendicular to the dentinal tubes. To the dentine elemental analysis, scanning electron microscopy (SEM) equipped in XRF (X-ray fluorescence) microprobe was used. Strontium concentration increased from 4.1% in the control group to 5.0% and 6.3% for the groups administered with...

BACKGROUND Many biominerals form from amorphous calcium carbonate (ACC), but this phase is highly unstable when synthesised in its pure form inorganically. Several species of earthworm secrete calcium carbonate granules which contain highly stable ACC. We analysed the milky fluid from which granules form and solid granules for amino acid (by liquid chromatography) and functional group (by Fouri...