192 research outputs found

    Continued corrosion protection of aluminium alloy 2024 through layered double hydroxide UV-degradation

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    ABSTRACT: In the last decade, the necessity to improve corrosion protection has dramatically affected the industry. Layered double hydroxides emerge as a possibility to overcome this problem due to their ability as a carrier of corrosion protection species. In this work, cerium cations, which possess corrosion protection ability, were incorporated in the LDH structure via partial substitution of aluminium cations. The changes occurring to LDH when exposed for an extended period to UV-radiation and its degradation with release of Ce3+ from the hydroxide layers has been studied and is presented in this work.info:eu-repo/semantics/publishedVersio

    Role of relativistic kinematics in describing two-quark systems

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    An attempt to incorporate relativistic kinematics in the description of light quark systems is made. It seems that the way of such incorporation along the suggestion expressed by R. Gaida and his collaborators is very promising. Comparison of these results with the experimental data concerning boson mass spectrum shows that this approach is among the best theoretical interpretation of the data

    Investigation of ferroelectric behavior of Bi(Fe,Sc)O3 multiferroics using piezoresponse force microscopy

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    This work was supported by the TUMOCS project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 645660

    Composition-, temperature- and pressure-induced transitions between high-pressure stabilized perovskite phases of the (1-x)BiFe0.5Sc0.5O3 - xLaFe0.5Sc0.5O3 series

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    Crystal structures of the high-pressure synthesized perovskite phases of the (1-x)BiFe0.5Sc0.5O3-xLaFe0.5Sc0.5O3 (0 ​= ​x ​≤ ​1) system and their temperature and pressure behaviours were studied using laboratory and synchrotron X-ray diffractions as well as neutron diffraction. At room temperature, the as-prepared phases with x ​≤ ​0.05 have an antipolar structure with the Pnma symmetry and with the √2ap ​× ​4ap ​× ​2√2ap superstructure (where ap is the pseudocubic perovskite unit-cell parameter). An incommensurately modulated phase with the Imma(00γ)s00 superspace group is observed for 0.10 ​= ​x ​≤ ​0.33, while a non-polar Pnma phase (√2ap ​× ​2ap ​× ​√2ap) is stable when x ​≥ ​0.34. The antipolar Pnma phase in the as-prepared samples with composition corresponding to x ​= ​0 transforms into the polar Ima2 one via irreversible annealing-caused transformation accompanied by a formation of a high-temperature intermediate polar R3c polymorph, while the antipolar Pnma phase in samples with x ​= ​0.05 is stable until the decomposition temperature. In the solid solutions with 0.10 ​= ​x ​≤ ​0.33, increasing temperature was found to result in a reversible transformation of the Imma(00γ)s00 phase into a non-polar Pnma one. The transition temperature decreases with increasing x. A hydrostatic pressure of few GPa was also shown to induce a reversible Imma(00γ)s00 → Pnma transformation.publishe

    Magnetic Diagram of the High-Pressure Stabilized Multiferroic Perovskites of the BiFe1-yScyO3 Series

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    Magnetic properties of the high-pressure stabilized perovskite BiFe1-yScyO3 phases (0.1 ≤ y ≤ 0.9) have been studied by means of magnetization measurements and neutron diffraction. The metastable perovskites of this series undergo irreversible polymorphic transformations upon annealing, the phenomenon referred to as conversion polymorphism. It has been found that the solid solutions with y ≥ 0.70 exhibit no long-range magnetic ordering regardless of their polymorph modification, while those with y ≤ 0.60 are all antiferromagnets. Depending on the scandium content, temperature and structural distortions, three types of the antiferromagnetic orderings, involving collinear, canted and cycloidal spin arrangements, have been revealed in the phases obtained via conversion polymorphism and the corresponding magnetic phase diagram has been suggested

    Exchange bias phenomenon in (Nd1-xYx)2/3Ca1/3MnO3 (x = 0, 0.1) perovskites

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    Exchange bias phenomenon, evident of antiferromagnetic-ferromagnetic phase segregation state, has been observed in (Nd1-xYx)2/3Ca1/3MnO3 (x = 0, 0.1) compounds at low temperatures. A contribution to the total magnetization of the compounds due to the ferromagnetic phase has been evaluated. It has been found that yttrium doping leads to the growth of the ferromagnetic phase fraction. The ferromagnetic phase in the doped compound has a lower coercivity Hc and more rectangular form of the hysteresis loop. The values of the exchange bias field HEB and coercivity are found to be strongly dependent on the cooling magnetic field Hcool. In sufficiently high magnetic fields, Hcool > 5 kOe, HEB in the doped compound is about twice as low as in the parent compound. This difference is attributed to a lower exchange interaction and higher saturation magnetization of the ferromagnetic phase in (Nd0.9Y0.1)2/3Ca1/3MnO3

    Sol-gel derived lanthanide-substituted layered double hydroxides Mg3/Al1-xLnx

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    Mg/Al/Ln (Ln = Nd, Sm, Eu) layered double hydroxides (LDHs) were synthesized using sol–gel method for the first time to the best our knowledge. The obtained materials were characterized by X-ray di raction analysis and fluorescence spectroscopy. The phase composition and luminescent properties of these LDHs were investigated and discussed. The Ln3+ substitution e ects were investigated in the Mg3Al1−xLnx LDHs by changing the Ln3+ concentration in the metal cation layers up to 10 mol%. It was demonstrated that only Mg3Al1−xEux LDHs showed luminescence properties, however, no any light emission was observed for the Mg3Al1−xNdx and Mg3Al1−xSmx LDH samplespublishe
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