Spin-1/2 Heisenberg Antiferromagnetic Chains in the Frustrated Spinel Lattice of GeCu2O4

A new homospin ferrimagnet BaMn9II(VO4)6(OH)2 exhibits a unique structural feature with a reverse triangular dipyramid Mn7 spin lattice, in which such a lattice can be considered as a broken spin lattice of B-sites in spinel compounds.

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A heterogeneous single Cu catalyst of Cu atoms confined in the spinel lattice of MgAl2O4 with good catalytic activity and stability for NO reduction by CO

Journal of Materials Chemistry A ◽

10.1039/c8ta11528a ◽

2019 ◽

Vol 7 (12) ◽

pp. 7202-7212 ◽

Cited By ~ 9

Author(s):

Jichun Wu ◽

Yuanzhi Li ◽

Yi Yang ◽

Qian Zhang ◽

Li Yun ◽

...

Keyword(s):

Catalytic Activity ◽

High Temperature ◽

No Reduction ◽

Confinement Effect ◽

No Reduction By Co ◽

Spinel Lattice ◽

Cu Catalyst ◽

Good Catalytic Activity

A heterogeneous single Cu catalyst exhibits good catalytic activity and durability at high temperature for NO reduction by CO due to the confinement effect of spinel lattice.

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Mg–Ti–spinel formation at the TiN/MgO interface by solid state reaction: Confirmation by high-resolution electron microscopy

Journal of Materials Research ◽

10.1557/jmr.1991.1744 ◽

1991 ◽

Vol 6 (8) ◽

pp. 1744-1749 ◽

Cited By ~ 20

Author(s):

L. Hultman ◽

D. Hesse ◽

W-A. Chiou

Keyword(s):

Electron Microscopy ◽

Solid State ◽

High Resolution ◽

Solid State Reaction ◽

Spinel Phase ◽

High Resolution Electron Microscopy ◽

Cation Sublattice ◽

Spinel Formation ◽

Spinel Lattice ◽

Resolution Electron

Mg–Ti–spinel formation along the interface of epitaxial TiN(100) films to MgO(100) substrates has recently been investigated by transmission electron microscopy (TEM) in the diffraction-contrast mode in samples grown at substrate temperatures higher than 800 °C and in such post-annealed at 850 °C. This phenomenon has now been investigated by high resolution electron microscopy of cross-sectional samples, at an acceleration voltage of 300 kV. Emphasis is given to the TiN/spinel and the spinel/MgO interfaces with respect to their structure and morphology. The results obtained confirm the previously drawn conclusions on the atomic mechanism of the solid state reaction during the spinel-forming process: The spinel, which most likely is of the composition Mg2TiO4, forms by counterdiffusion of the cations Ti4+ and Mg2+ in the rigid oxygen frame provided by the fcc oxygen sublattice of MgO. The latter is completely taken over by the spinel lattice. This “host” character of the MgO substrate lattice for the topotaxial growth of the spinel lattice and the coherency of the solid state reaction with respect to the lattices of all the phases involved are demonstrated. Misfit dislocations at the TiN/MgO, TiN/spinel, and the spinel/MgO interfaces, as well as antiphase boundaries of the cation sublattice of the spinel phase, have also been observed.

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Decomposition Of Co2 To Carbon By H2-Activated Ni(II)- And Co(II)-Bearing Ferrites At 300°C

MRS Proceedings ◽

10.1557/proc-344-63 ◽

1994 ◽

Vol 344 ◽

Author(s):

Tatsuya Kodama ◽

Taizo Sano ◽

Shig-Ger Chang ◽

Masamichi Tsuji ◽

Yutaka Tamaura

Keyword(s):

Lattice Constant ◽

Type Structure ◽

Metal Substitution ◽

Spinel Type ◽

Batch System ◽

Spinel Lattice ◽

Fe Content ◽

C Decomposition ◽

Different Levels

AbstractThe reactivity of the H2-activated Ni(II)- and Co(II)-bearing ferrites with different levels of metal substitution have been studied for CO2 → C decomposition in comparison with that of the H2-activated magnetite. Ni 2+ and Co2+ have been substituted for Fe2+ or Fe3+ in magnetite with the spinel-type structure up to 14 % and 26 % of the mole ratio of Ni2+ and Co2 + to the total Fe content respectively. The reactivity of the Ni(II)- and Co(II)-bearing ferrite increased with the level of metal substitution. Especially, the Ni(II) substitution significantly facilitated the CO2 → C decomposition in a batch system. The rates of H2-activation (reduction) and CO2-decomposition (oxidation) for N(II)-bearing ferrite were studied by a thermogravimeteric analysis. The rates of both H2-activation and CO2-decomposition were much improved in the Ni(II)-bearing ferrite with the Ni(II)/Fetoul mole ratio of 14%. It is considered that the reduced Ni(II) ions which were formed on the surface of the ferrite is very active to facilitate both dissociation reactions of 1) H2 → 2 Hads and 2) CO2→ Cads + 2Oads,. From the change in the lattice constant of the Ni(II)-bearing ferrite during the H2-activation and CO2-decomposition, the oxygens in CO2 were considered to be incorporated into the oxygen deficient spinel lattice of the oxygen deficient Ni(II)-bearing ferrite which had been formed by the H2-activation.

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Influence of Zinc Injection on Dose Rate from Primary System Loops for PWR Units and Predictive Assessments for VVER-1000

Nuclear and Radiation Safety ◽

10.32918/nrs.2017.1(73).11 ◽

2017 ◽

Author(s):

T. Maltseva ◽

O. Horpinchenko ◽

D. Gumenyuk

Keyword(s):

Oxide Film ◽

Dose Rate ◽

Zinc Concentration ◽

Primary System ◽

Cation Vacancies ◽

Dose Rates ◽

Spinel Lattice ◽

Predictive Assessments

The paper analyzed the advisability of zinc injection into the VVER primary system coolant in order to minimize radioactive fields of equipment. In the western NPPs with PWR, zinc injection into the coolant leads to permanent decrease of dose rates caused by radioactive cobalt. Zinc is introduced into the oxide film on the primary system equipment surfaces to form the most stable zinc spinel, which prevents the further introduction of radioactive cobalt in the oxide film. Predictive assessments for VVER-1000 show that under the zinc concentration of µg/dm3 in the coolant, cation vacancies in the spinel lattice will be occupied mostly by zinc, preventing the penetration of cobalt in the spinel and increase of radioactive fields of equipment.

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