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Deep centres of ZnS:Ga single crystals are investigated by the following methods: impurity electroabsorption, photoconductivity, and luminescence. From the measurements the spectrum of deep levels is determined. It is assumed that the luminescence spectrum of the investigated samples is in general determined by the radiative recombination of donor—acceptor pairs, where the pair consists of the complex (VZnGaZn)′ as acceptor and of gallium on zinc site as donor.

Aim. The work was performed with the purpose to study antibacterial action of millimolar concentrations of copper and zinc ions, used as sulfates or chlorides in the cultures of S.pyogenes and S.agalactiae. Materials and methods. Suspensions of the S.pyogenes and S.agalactiae bacteria which contained 108 CFU/ml were sown by the lawns into the standard Petri dishes coated with the supplemented Nutrient Agar. 30 min later the salt solutions of copper or zinc were added by the 5 pi drops on the surfaces of the lawns with use of 36-channel stamp replicator. The salt solutions contained copper or zinc at the concentrations ranged between 5xl0-3 M to 5xl0_1 M of the metals. Then the dishes containing bacterial cultures were incubated for 24 hrs at 37°C followed by measuring diameter of the area of culture growth inhibition. The probes of material obtained from the centers of the stunting areas were passed into the centrifuge tubes with the supplemented Nutrient Broth, incubated for up to five days at 37°C and tested for the Broth clarity. Results. In presence of the metal concentrations ranged between 50 to 500 mM the inhibitory action of zinc sulfate towards S.pyogenes bacteria was 1.5 - 1.7 times higher (p

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