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  • Author or Editor: A. Davydov x
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Abstract  

The transfer and separation of the chlorides of a number of rare-earth and actinide elements and their mixtures has been investigated in the flow of gas-carrier along a quartz tube under temperature gradient. The dependence of the position (characteristic temperature) and shape of the condensation (or sorption) peak of cerium chloride in the gradient region of the tube on the amount of substance in the starting zone has been studied. Weight limits determining the behaviour of the substance as micro- or macrocomponent and its transfer by adsorption or condensation mechanism have been established. The mutual effect of elements in the La−Ce, Am−U, Np−U systems has been studied. It is shown that in the case, when the condensation peak of the macrocomponent overlaps the adsorption zone of the microcomponent, the position of the adsorption peak is shifted and the effectivity of the micro- and macrocomponent separation deteriorates in comparison with the separation of microamounts of elements. If the condensation of the macrocomponent occurs in temperature zones distant from that of the microcomponent adsorption, the position of the latter does not change and the degree of purification of the microcomponent increases.

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Abstract  

Volatile einsteinium hexafluoroacetylacetonate complexes have been syntehsized. Their sublimation and thermochromatographic behaviour has been studied in the presence of -diketone vapours. Interaction of einsteinium di-and trichloride with hexafluoracetylacetone vapours is discussed.

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Abstract  

The heterogeneous ligand exchange synthesis of volatile -diketonates of some actinides /230Th,233U,239Pu,241Am/ and fission product elements /90Sr,90Y,113Sn,113mIn/ and their separation by means of thermochromatography and fractional sublimation are reported. The methods are efficient for the separation of elements of different oxidation states.

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Abstract  

The temperature dependence of the vapour pressure of californium-249 hexafluoroacetylacetonate adducts with tributylphosphate /TBP/, tributylphosphineoxide /TBPO/ and dipropylsulphoxide /DPSO/ is determined. The enthalpy and entropy sublimation of the compounds are calculated.

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Abstract  

A possibility to use exchange reaction of metal \-diketonates and the vapours of \-diketones for the separation of volatile \-diketonate complexes by the method of fractional sublimation has been studied. When a mixture of thenoyltrifluoroacetonates of95Zr–95Nb and Th–233Pa is treated with a carrier gas containing hexafluoroacetylacetone vapours, zirconium and thorium, unlike niobium and protactinium, form volatile hexafluoroacetyl-acetonates which sublimate quite completely at 115°C. Niobium and protactinium remain in the initial sample in the form of nonvolatile compounds.

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Abstract  

Separation of239Np from243Am including extraction of Np/IV/ and Am/III/ by thenoyltrifluoroacetone solution in benzene, transformation of thenoyltrifluoroacetonates into volatile hexafluoroacetylacetones in the flow of a carrier gas saturated with hexafluoroacetylacetone vapours are described.

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Cereal Research Communications
Authors: S. Osipova, A. Permyakov, M. Permyakova, V. Davydov, T. Pshenichnikova, and A. Börner

Variation in tolerance of prolonged drought was identified among a set of single chromosome bread wheat substitution lines, involving the replacement of each cv. Chinese Spring chromosome in turn with its homologue from a synthetic hexaploid (Triticum dicoccoides × Aegilops tauschii). Water stress was applied under controlled conditions by limiting the supply of water to 30% from 100% aqueous soil. The reaction to the resulting long-term drought stress was quantified by three indices, based on grain yield components. Enhanced drought tolerance was associated with the presence of donor chromosomes 1A, 5A, 1D, 3D, 5D and 6D, and enhanced susceptibility with chromosomes 3A, 4B and 7D.

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Abstract  

Volatile hexafluoroacetylacetonates of hafnium, ytterbium, scandium, as well as scandium trifluoroacetylacetonate and acetylacetonate have been obtained by interaction of -diketone vapours with radionuclides formed in a cyclotron in on-line operation. The application of volatile -diketonates for transport and separation of the short-life isotopes of metallic elements has been shown.

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Abstract  

Volatile hexafluoroacetylacetonates of mendelevium and daughter fermium were first obtained by the interaction of hexafluoroacetylacetone with256Md radionuclide formed in the cyclotron under on-line conditions as well as by the heterophase exchange of ligands. Thermochromatographic behaviour of the complexes synthesized was studied in a flow of a carrier-gas saturated with ligand vapours.

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