The Experts below are selected from a list of 27020907 Experts worldwide ranked by ideXlab platform
Katsuo Kato - One of the best experts on this subject based on the ideXlab platform.
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Space‐Group Determination of the Orthorhombic Form of NaV6O11
Journal of Applied Crystallography, 1995Co-Authors: Yasushi Kanke, Hirotake Shigematsu, Ken-ichi Ohshima, Katsuo KatoAbstract:The unit cell and space group of orthorhombic NaV6OII (low-temperature form) are found by an X-ray singlecrystal diffraction study at 300 K (hexagonal, P63/mmc), 100 K (hexagonal, P63mc) and 20 K (orthorhombic). The orthorhombic form (o) shows no superstructure and its unit cell is related to the hexagonal one (h): ao ~" ah 4- bh, bo --~ --ah 4- bh and Co -~ ch. Bijvoet-pair examination confirms that it crystallizes in the noncentrosymmetric space group Cmc21. The hexagonal (P63mc)-orthorhombic (Cmc21) structural phase transition is proved to be of second order.
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Synthesis and magnetic property of NaFe3V9O19
Journal of Solid State Chemistry, 1991Co-Authors: Y. Kanke, Eiji Takayama-muromachi, Y. Uchida, Katsuo Kato, S. TakekawaAbstract:A new phase, NaFe3V9O19, was found. It crystallizes hexagonal with a = 5.8400 ± 0.0001 and c = 22.8058 ± 0.0005 A. Its possible space groups are P63mmc, P62c, or P63mc. The composition and the crystal data indicate that NaFe3V9O19 is isostructural with magnetoplumbite-type compounds. NaFe3V9O19 shows a uniaxial magnetism with the easy axis of magnetization parallel to [001] below the transition temperature, around 240 K.
Aleksey N. Yakovlev - One of the best experts on this subject based on the ideXlab platform.
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Improved phase stability of the metastable K2GeF6:Mn4+ phosphors with high thermal stability and water-proof property by cation substitution
Chemical Engineering Journal, 2020Co-Authors: Tianchun Lang, Tao Han, Shuangqiang Fang, Wang Jinyu, Shixiu Cao, Lingling Peng, Bitao Liu, V. I. Korepanov, Aleksey N. YakovlevAbstract:Abstract K2GeF6:Mn4+ (KGFM) phosphors with very poor water-proof property in HF solution transform automatically from P63mc hexagonal phase to P 3 ¯ m1 trigonal phase. By substituting Ge4+ ion with Si4+ ion, the metastable P63mc hexagonal K2(Ge1-xSix)F6:Mn4+ (KGSFM) with an obvious zero-phonon line peaking at 623.8 nm is stabilized in HF solution. When x = 0.3, the photoluminescence intensity of KGSFM keeps 78% after 168 h in water as well as it increases by 14% at 150 °C (423 K) more than that of KGFM. By using KGSFM the fabricated WLEDs exhibit the high color-rendering index (Ra = 92) and low correlated color temperature (CCT = 3810 K). These results demonstrate that KGSFM solid solution with efficient red emission, meritorious water-proof and high thermal stability is a promising phosphor for the commercial application in the WLEDs and wide-gamut displays.
A. Lecerf - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and Crystal Structures of Cd(OH)Cl and Cu(OH)Cl and Relationship to Brucite Type
Journal of Solid State Chemistry, 2000Co-Authors: Yannick Cudennec, A. Riou, Y. Gérault, A. LecerfAbstract:Synthesis of single crystals of Cd(OH)Cl and Cu(OH)Cl allowed to revisit the structure of these hydroxychlorides and confirm their space group: P63mc ( R = 0.041; Rw = 0.050 ) for Cd(OH)Cl and P21/c ( R = 0.051; Rw = 0.072 ) for Cu(OH)Cl. Positions of hydrogen atoms were determined and an hypothesis of hydrogen bonds is discussed in relation with the infrared spectra. A comparison of the structures shows that an isomorphism is not possible between the two compounds, due to the important Jahn-Teller effect of divalent copper. On the other hand, a structural relationship exists between Cd(OH)Cl and beta-Cd(OH)2 which belongs to the brucite type family.
Tianchun Lang - One of the best experts on this subject based on the ideXlab platform.
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Improved phase stability of the metastable K2GeF6:Mn4+ phosphors with high thermal stability and water-proof property by cation substitution
Chemical Engineering Journal, 2020Co-Authors: Tianchun Lang, Tao Han, Shuangqiang Fang, Wang Jinyu, Shixiu Cao, Lingling Peng, Bitao Liu, V. I. Korepanov, Aleksey N. YakovlevAbstract:Abstract K2GeF6:Mn4+ (KGFM) phosphors with very poor water-proof property in HF solution transform automatically from P63mc hexagonal phase to P 3 ¯ m1 trigonal phase. By substituting Ge4+ ion with Si4+ ion, the metastable P63mc hexagonal K2(Ge1-xSix)F6:Mn4+ (KGSFM) with an obvious zero-phonon line peaking at 623.8 nm is stabilized in HF solution. When x = 0.3, the photoluminescence intensity of KGSFM keeps 78% after 168 h in water as well as it increases by 14% at 150 °C (423 K) more than that of KGFM. By using KGSFM the fabricated WLEDs exhibit the high color-rendering index (Ra = 92) and low correlated color temperature (CCT = 3810 K). These results demonstrate that KGSFM solid solution with efficient red emission, meritorious water-proof and high thermal stability is a promising phosphor for the commercial application in the WLEDs and wide-gamut displays.
Antoine Maignan - One of the best experts on this subject based on the ideXlab platform.
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Magnetodielectric Effect in Crystals of the Noncentrosymmetric CaOFeS at Low Temperature
Inorganic chemistry, 2015Co-Authors: C. Delacotte, Olivier Perez, Alain Pautrat, David Berthebaud, Sylvie Hébert, Emmanuelle Suard, Denis Pelloquin, Antoine MaignanAbstract:Single crystals of the stoichiometric iron calcium oxysulfide CaOFeS have been grown by a solid-state reaction. Structural analysis of CaOFeS at room temperature by combining single-crystal X-ray diffraction data and transmission electron microscopy leads to a stoichiometric hexagonal noncentrosymmetric P63mc layered structure isostructural to CaOZnS. It is built from alternating layers made of FeOS3 tetrahedra sharing sulfur apexes and stacked with Ca2+ planes. All Fe–O bonds are parallel to the stacking axis; this breaks the centrosymmetry, leading to a polar structure. The dielectric measurements reveal the existence of a magnetodielectric effect near 33 K in good agreement with the Neel temperature, as evidenced near 35 K by specific heat measurements reported by a different group.
