A44_ Effect of Nano-Sized ZnO on Electrical & Structural Properties of High Temperature Tl2-x HgxBa2Ca2Cu3O10-δ Superconductors

The electrical resistivity of high temperature superconductivity Tl2-xHgxBa2Ca2Cu3O10-δhas been measured in the temperature range from 90K to 330K. These results showed that the critical temperature of the zero resistivity increases from 127K to 138K ,when the Hg concentration increased from 0 to 0.5. The structure of the Tl2-xHgxBa2Ca2Cu3O10-δcompound has also investigated by using X- ray diffraction technique. This compound has tetragonal type structure with a=b=5.36A & c=36.09A and the magnitude of c-axis increases to 37.8A when x increased to 0.5. Nano ZnO was add to the sample with concentration (0-1) wt% of the ( Tl2-xHgxBa2Ca2Cu3O10-δ) samples mass. The effect of the nano ZnO concentration substitution on the samples investigated on structure and critical temperature of the best sample properties (when x=0.5)and showed that the structure remains tetragonal and c-axis increased to 39.2A when nano sized concentration 0.8% and Tcincrease to 146K but c-axis decreased to 38.4A and Tcdecreased to 143K when the ZnO concentration 1%.

Photocatalytic Water Splitting and Photocatalytic Degradation in Aqueous GdVO4 Suspensions under Simulated Solar Irradiation

GdVO4 was synthesized by solid state reaction at high temperature and characterized by XRD, UVvisible DRS, BET and SEM. XRD analysis of GdVO4 showed its structure was of tetragonal type. When GdVO4 was loaded with 0.3 wt% Pt, it showed the better photocatalytic activity for water splitting under simulated solar irradiation, and the amounts of the produced hydrogen in pure water were about 9.33 μmol under the irradiation of simulated solar for 6 h. Furthermore, photodegradation of Rhodamine B (Rh B ) on the samples were investigated under simulated solar irradiation.

Kristallstrukturen mit Bausteinen des CaBe2Ge2-Typs – Die Verbindungen Sm2Pt6P3 und Ca2Pd3Sb4 / Crystal Structures with CaBe2Ge2-Type Units – The Compounds Sm2Pt6P3 and Ca2Pd3Sb4

Single crystals of Sm2Pt6P3 (a = 4.095(1), c = 45.313(9) Å ) were prepared by heating the elements in a melt of NaCl/KCl at 1100°C. The compound crystallizes with a new tetragonal type of structure (I41/amd; Z = 4) consisting of units which correspond to the CaBe2Ge2 type except for one significant difference: In the layer of PPt4 tetrahedra only two of four P positions are occupied. Therefore this layer is built up by corner- instead of edge-sharing PPt4 tetrahedra. Four of these units are stacked along [001]. Single crystals of Ca2Pd3Sb4 (a = 4.506(1), c = 41.538(8) Å ) were obtained by reaction of the elements at 900°C. The crystal structure (I4/mmm; Z = 4) consists of two blocks. The first one has the composition CaPd2Sb3 and can be derived from the CaBe2Ge2 type. In the second one (formula CaPdSb) the atoms are arranged analogous to the CeMg2Si2 type. Both blocks alternate along [001]

Diffuse scattering and disorder in zirconia

Diffuse scattering in zirconia is reviewed mainly for yttria- and calcia-stabilized material. Common general disorder features are explained by rhombohedral-type and/or tetragonal-type short-range and long-range ordered clusters or “domains”. Differences are comparatively discussed on the basis of available experimental data and theoretical work.