Chemistry June 2003 Vol 52/2 []

CONTENTS & ABSTRACTS

InEnglish. Summaries in Estonian

Proceedings of the Estonian Academy of Sciences.

Chemistry



Volume 52 No. 2June 2003



Photovoltaicstructures formed by thermal annealing of electrodeposited CuInSe2in H2S; 51–58

Julia Kois, Sergei Bereznev, Enn Mellikov, and Andres Öpik

Abstract. Thin polycrystalline CuInSe2 films were electrodepositedonto ITO/In(O,S) and ITO covered glasses from aqueous solutions with variousratios of elements. The obtained structures were annealed at 450 °C in H2S. Current-voltage and impedance measurementswere carried out for the produced heterostructures. The electronic quality ofCuInSe2 was found to have improved after thermal and chemicaltreatment.

Key words: photovoltaic structure, electrodeposition, thermal treatment,chemical treatment.

Observations of ice impurities in someFinnish lakes; 59–75

Matti Leppäranta, MattiTikkanen, and Juhani Virkanen

Abstract. Ice, snow, and watersamples from four lakes and three years were analysed for the impurities (frommeltwater). The ice thickness was 30–60 cm. The average concentration ofdissolved matter was 11–17 mg/L in ice and 15–23 mg/L in snow. Thesevalues were 10–40% of the concentration of dissolved matter in lake water. Thesediment content was 2–12 mg/L in all media. The mean metal levels in theice were 100 mg/L for Al and Fe;30 mg/L for Zn; 1–10 mg/L for Cu, Mn, and Ni;and below 0.1 mg/L for Cd. These levelswere 0.5–2.0 times as high as those in the water. Snowfall is a significantsource for many metals. Nutrient levels in the ice were: total-P 2 mg/L; total-N 200 mg/L; SO4, Na, and Cl1 mg/L; Ca 2 mg/L; and Mg and K 0.5 mg/L. The levels in the icewere by one order of magnitude lower than in the water. Two river ice siteswere sampled for reference. These showed by an order of magnitude highersediment content than the lake ice.

Key words: lake ice, Finland, impurities, sediments, chemical elements.

Assessmentof occupational exposure to asbestos in energy and transport enterprises;76–82

Maie Kangur and Vello Jaakmees

Abstract. Occupational exposure to asbestos in energy and transportenterprises was studied. For the assessment of occupational exposure toasbestos inspections of buildings, asbestos identifica­tion in materialsamples, and workplace measurements were included. The occurrence of asbestosin buildings from various time periods was studied using relevant acknowledgedmethods. The methods of polarized light and phase-contrast optical microscopywere used in the qualitative analysis of material samples and in the countingof asbestos fibres in air samples.

Key words: asbestos, identification, occupational exposure.

Astudy on three-phase ozonation; 83–91

Rein Munter and Yelena Veressinina

Abstract. The paper deals withozone solubility and reactions in octane and octane–water mixtures. It is shownthat ozone solubility in pure octane is about twice as high as in water at thesame temperature. In two-phase mixtures, 50% of octane and 50% of water, thesolubility coefficients of ozone in both phases are close to each other. It wasestablished that during the ozonation of pure octane and octane–water mixturesorganic peroxides were formed, which diffused totally from the organic to thewater phase. The ozonation of salicylic, benzoic, and stearic acids was studiedin octane–water mixtures.

Key words: ozone, solubility,octane, octane–water mixtures, organic peroxides, salicylic acid, benzoic acid,stearic acid, oxidation.

Mischmetall, zinc–copper couple, and Dewardaalloy in the pinacol coupling of aldimines; 92–96

Eerold Vellemäe, OlgaTšubrik, Olavi Loog, Sirje Mäeorg, and Uno Mäeorg

Abstract. New cheap reagents for the pinacol type coupling reaction ofaldimines such as mischmetall, Zn–Cu couple, and Dewarda alloy are introduced.A relatively simple procedure for this reaction is described. Zn–Cu coupleshould be preferred because of economical considerations.

Key words: mischmetall, Zn–Cu couple, Dewarda alloy, imine, pinacolcoupling.