10 research outputs found

    Synthesis, structure and dielectric properties of a new family of phases, ABC3O11 : A = La, Pr, Nd, Sm, Gd; B = Zr, Hf; C = Ta, Nb

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    Eight new phases with the general formula of ABC3O11 with different rare earth, (Zr, Hf), (Nb, Ta) combinations, have been prepared by solid-state reactions at a temperature range of 1200–1500 °C. The new phases—LaHfTa, LaHfNb, LaZrNb, PrHfTa, NdHfTa, NdHfNb, SmHfTa and GdHfTa—are characterised by X-ray and neutron diffraction data at room temperature and variable frequency impedance measurements. They are isostructural with LaZrTa3O11 which consist of alternating single layers of UO7 pentagonal bipyramids and octahedra as shown by Rietveld refinement of X-ray and neutron powder diffraction data. Lattice parameters decrease with decreasing size of rare earth element substitution at A-site, and of all, Gd is the smallest rare earth that formed LaZrTa3O11 analogues. Detailed attempts of attained and unattainable LaZrTa3O11 analogues with different temperatures are included in this paper. All phases are highly insulating with temperature-independent bulk permittivities in the range 17 to 50; LaHfNb demonstrates the highest permittivity. Arrhenius plot shows that the activation energies are in the range 0.8 to 1.94 eV

    Introduction—Food Security and Food Waste Reduction: A Social Innovation Approach to Current Social, Environmental, and Political Concerns

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    This chapter presents the research rationale underpinning the book. It addresses the intertwining challenges of food security and surplus food management, discussing recent data and literature. It also presents how social innovation is conceptualized in the book as the theoretical framework to analyse partnerships between business and non-profit organisations in managing food surplus. The methodology of the research is also detailed, along with the book structure

    Voronoi–dirichlet polyhedra in crystal chemistry: theory and applications

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    Structural Chemistry

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    Uran und Sauerstoff

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