نتایج جستجو برای: tetragonal structure
تعداد نتایج: 1570279 فیلتر نتایج به سال:
manganese oxide nanoparticles (mn3o4-nps) were prepared using precipitation method. the prepared nanoparticles were characterized by a number of techniques, including x-ray diffraction (xrd) analysis, scanning electron microscopy (sem), transmission electron microscopy (tem) and fourier transforms infra red (ft-ir) spectroscopy. the xrd pattern showed that the structure of mn3o4-nps was tetrago...
Abstract Commercial hydrothermally synthesized BaTiO 3 powder with a cubic structure was annealed in temperature range of 650 °C–900 °C, and the cubic-tetragonal transition microstructure evolution were investigated relation to annealing process. The used had below an 800 °C tetragonal above 850 °C. Particle growth occurred under low activation energy ∼33.2 kJ mol −1 because nanocrystalline siz...
Band Jahn-Teller type structural instabilities of cubic Mn(2)YZ Heusler compounds causing tetragonal distortions can be predicted by ab initio band-structure calculations. This allows for identification of new Heusler materials with tunable magnetic and structural properties that can satisfy the demands for spintronic applications, such as in spin-transfer torque-based devices.
The hard core Yukawa system, consisting of particles with an impenetrable core and interacting via a repulsive Yukawa pair potential, is known to solidify either in a bcc or fcc crystal. Using optimization strategies based on genetic algorithms we give evidence that at zero temperature an additional centred tetragonal phase structure in the range of high packing fractions emerges.
The surface chemical properties of undoped tetragonal ZrO2 and the gas-phase dependence of the tetragonal-to-monoclinic transformation are studied using a tetragonal ZrO2 polymorph synthesized via a sol-gel method from an alkoxide precursor. The obtained phase-pure tetragonal ZrO2 is defective and strongly hydroxylated with pronounced Lewis acidic and Brønsted basic surface sites. Combined in s...
The incommensurate modulation in a synthetic iron-bearing akermanite, Ca2(Mg, Fe )Si207, has been determined at room tempe~ature by the five-dimensional refinements of the structure. The basic structure is tetragonal P4 21m with unit-cell dimensions a =7.8679(3), c ~5.0144(2)A, V=31OAl(2)A3, 2=2, M=286.69, Dx =3.067Mg . m-3, MoKa with graphite monochromator, J1 =3.199mm-l, F(000)=284A9, Mg/(Mg+...
Ab initio random structure searching using density functional theory is used to determine the ground-state structures of atomic metallic hydrogen from 500 GPa to 5 TPa. Including proton zero-point motion within the harmonic approximation, we estimate that molecular hydrogen dissociates into a monatomic body-centered tetragonal structure near 500 GPa (r(s)=1.23) that remains stable to 1 TPa (r(s...
In this study, we demonstrate a one-pot mechanochemical synthesis of the nanocomposite composed of stannite Cu2FeSnS4 and rhodostannite Cu2FeSn3S8 nanocrystals using a planetary ball mill and elemental precursors (Cu, Fe, Sn, S). By this approach, unique nanostructures with interesting properties can be obtained. Methods of XRD, Raman spectroscopy, UV-Vis, nitrogen adsorption, SEM, EDX, HRTEM, ...
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