共查询到20条相似文献,搜索用时 15 毫秒
1.
Crystallography Reports - The defect structure of as grown single crystals Sr1 – xSmxF2 + x (x = 0.14, 0.26) and... 相似文献
2.
3.
Crystallography Reports - The compositions of nonstoichiometric phases Pb1 – xRxF2 + x (CaF2 type, R is a rare-earth element) have been optimized with... 相似文献
4.
Sulyanova E. A. Bolotina N. B. Kalukanov A. I. Sorokin N. I. Karimov D. N. Verin I. A. Sobolev B. P. 《Crystallography Reports》2019,64(1):41-50
Crystallography Reports - The defect structure of as-grown SrF2 and nonstoichiometric phases Sr1 – xLaxF2 + x (x = 0.11, 0.20, 0.32, 0.37, 0.47) single... 相似文献
5.
Crystallography Reports - Optimization of the compositions of Cd1–xRxF2+x nonstoichiometric phases (CaF2 type, R is a rare-earth element) for the ionic conductivity and thermal stability is... 相似文献
6.
7.
Koldaeva M. V. Rudneva E. B. Manomenova V. L. Voloshin A. E. Masalov V. M. Zhokhov A. A. Emelchenko G. A. 《Crystallography Reports》2019,64(6):926-931
Crystallography Reports - K2Ni(SO4)2 · 6H2O (KNSH), K2Co(SO4)2 · 6H2O (KCSH), and K2NixCo(1 – x)(SO4)2 · 6H2O (KCNSH) crystals have been grown by traditional... 相似文献
8.
Sedykh V. D. Medvetskaya I. Yu. Pchelina D. I. Chistyakova N. I. Rusakov V. S. Alekhina Yu. A. 《Crystallography Reports》2020,65(3):347-351
Crystallography Reports - Mössbauer and magnetic study of calcium-doped lanthanum manganites La1 – xCaxMn0.98Fe0.02O3 + δ (x = 0.05, 0.10, 0.20)... 相似文献
9.
Sheleg A. U. Gremenok V. F. Sereda A. S. Hurtavy V. G. Chumak V. A. Tsyrelchuk I. N. 《Crystallography Reports》2019,64(2):266-269
Crystallography Reports - The high-temperature orthorhombic phase of Cu2CdGeSe4 quaternary compound, tetragonal phase of Cu2CdSnSe4 compound, and Cu2CdGexSn1 – xSe4 solid... 相似文献
10.
Randilynn Christensen Jennifer Byer Garrett Olson Steve W. Martin 《Journal of Non》2012,358(4):826-831
The mixed glass former effect (MGFE) is defined as the non-linear and non-additive change in the ionic conductivity with changing glass former fraction at constant modifier composition between two binary glass former compositions. In this study, sodium borophosphate glasses, 0.35Na2O + 0.65[xB2O3 + (1 ? x)P2O5] with 0 ≤ x ≤ 1, have been prepared and their glass transition temperatures (Tg) have been examined as an alternative indicator of the MGFE and as an indicator of changes in the short range order (SRO) structural network units that could cause or contribute to the MGFE. The changes in Tg show a positive non-additive and non-linear trend over the changing glass former fraction, x. The increase in Tg is related to the increasing number of bridging oxygens (BO) in the glass samples, which is caused by the increase in the number of tetrahedral boron, B4, units in the SRO structure. 相似文献
11.
Randilynn Christensen Jennifer Byer Garrett Olson Steve W. Martin 《Journal of Non》2012,358(3):583-589
The mixed glass former effect (MGFE) is defined as a non-linear and non-additive change in the ionic conductivity with changing glass former fraction at constant modifier composition between two binary glass forming compositions. In this study, mixed glass former (MGF) sodium borophosphate glasses, 0.35 Na2O + 0.65 [xB2O3 + (1 ? x)P2O5], 0 ≤ x ≤ 1, which have been shown to have a strong positive MGFE, have been prepared and their physical properties, density and molar volume, have been examined as predictors of structural change. The density exhibits a strong positive non-linear and non-additive change in the density with x and a corresponding negative non-linear and non-additive change in the molar volume. In order to understand the structural origins of these changes, a model of the molar volume was created and best-fit to the experimentally determined molar volumes in order to determine the volumes of the short range order (SRO) structural units in these glasses, how these volume change from the molar volumes of the binary glasses, and how these volumes change across the range of x in the ternary glasses. The best-fit model was defined as the model that required the smallest changes in the volumes of the ternary phosphate and borate SRO structural groups from their values determined by the densities of the binary sodium phosphate and sodium borate glasses. In this best-fit molar volume model, it was found that the volumes of the various phosphate and borate SRO structural groups decreased by values ranging from a minimum value of ~ 1% for x = 0.1 and 0.9 to a maximum value of ~ 6% for the phosphate and ~ 9% for the borate SRO groups at the minimum in molar volume at x = 0.4. The free volume was found to have a negative deviation from linear which is unexpected given the positive deviation in ionic conductivity. 相似文献
12.
Crystallography Reports - The quaternary semiconductor compounds Cu2ZnSnSe4, Cu2ZnSiSe4, and Cu2ZnSn1 – xSixSe4 solid solutions on their basis have been synthesized from the... 相似文献
13.
B. Dieudonné B. Boulard G. Alombert-Goget Y. Gao A. Chiasera S. Varas M. Ferrari 《Journal of Non》2012,358(18-19):2695-2700
Pr3 +–Yb3 +‐codoped fluoride glass waveguides have been synthesized by Physical Vapor Deposition (PVD). A study of the evaporation of ternary mixture of rare earth fluorides LaF3–PrF3–YbF3 has been necessary to control the doping of the evaporated glass. Optical and spectroscopic studies have been performed in both bulk and waveguide configuration. Red, orange, green and blue emissions in Pr3 +–Yb3 +-codoped lanthanum flurozirconate glasses called ZLAG have been investigated, by exciting in the blue or in the infra-red at 980 nm. Bulk samples with different dopant concentrations (0.25–3 mol% for Pr3 + and 0–5 mol% for Yb3 +) have been studied in order to optimize the Pr3 + emission. It has been shown than the luminescence is similar in bulk and waveguide upon excitation at 980 nm. 相似文献
14.
Somov N. V. Chausov F. F. Lomova N. V. Vorob’yov V. L. Kazantseva I. S. Sapozhnikov G. V. Zakirova R. M. 《Crystallography Reports》2020,65(5):726-739
Crystallography Reports - The structural features of the phases formed during crystallization of mixed copper and nickel complexes with nitrilotris(methylenephosphonic acid)... 相似文献
15.
Keiichi Minami Fuminori Mizuno Akitoshi Hayashi Masahiro Tatsumisago 《Journal of Non》2008,354(2-9):370-373
The 70Li2S · (30 ? x)P2S5 · xP2O5 (mol%) oxysulfide glasses were prepared by the melt quenching method. The glasses were prepared in the composition range 0 ≦ x ≦ 10. The glass–ceramics were prepared by heating the glasses over crystallization temperatures. The POnS3?n (n = 1–3) oxysulfide units were produced in the glasses and glass–ceramics by partial substituting P2O5 for P2S5. In particular, the P2OS64? unit would be produced by substituting a small amount of P2O5 for P2S5. The oxygen atoms were incorporated into the Li7P3S11 crystal structure because the diffraction peaks of the oxysulfide glass–ceramic shifted to the higher angle side. The glass–ceramic with 3 mol% of P2O5 exhibited the highest conductivity of 3.0 × 10?3 S cm?1 and the lowest activation energy for conduction of 16 kJ mol?1. The P2OS64? dimer units in the oxygen-incorporated Li7P3S11 crystal would improve conductive behavior of the Li2S–P2S5 glass–ceramics. 相似文献
16.
Sulphide glasses doped with rare-earth ions have been demonstrated to be suitable for photonic applications such as optical amplifiers, up-converters and fiber lasers. The substitution of metal halides into the glass network has been shown to result glasses with desirable properties in terms of quantum efficiency and fiber manufacture [J.R. Hector, J. Wang, D. Brady, M. Kluth, D.W. Hewak, W.S. Brocklesby, D.N. Payne, Journal of Non-Crystalline Solids 239 (1998) 176]. To assist in the understanding of this improvement a structural analysis of glasses with a composition xCsCl(1 ? x)Ga2S3 has been undertaken in order to examine the nature of the gallium environment. Information collected by high energy X-ray diffraction and neutron diffraction have been analyzed to permit the identification of the structural units as Ga centered tetrahedra. The interconnection between the tetrahedra was found to be predominantly corner sharing. 相似文献
17.
Yu. V. Shaldin S. Matyjasik N. E. Novikova M. Tseitlin E. Mozhaev M. Roth 《Crystallography Reports》2010,55(6):1012-1018
The temperature dependences of the pyroelectric coefficients of KTiOAsO4 and RbTiOAsO4 single crystals grown by flux crystallization have been investigated in the temperature range of 4.2–300 K. With an increase
in temperature, superionic conductivity first arises in KTiOAsO4 (at T > 200 K) and then (at T > 270 K) in RbTiOAsO4. This conductivity is much higher in the samples polarized at T = 4.2 K. An exponential change in the crystal resistivity along the polar direction is simultaneously observed. The results
of measurements in the range of 4.2–200 K indicate larger values of pyroelectric coefficients when compared with potassium
and rubidium titanyl-phosphate crystals. A correlation between the pyroelectric coefficients and a change in the lattice constants
at isomorphic substitutions of K atoms for Rb and P atoms for As has been revealed within the symmetry approach. 相似文献
18.
Ternary tellurite glasses with the chemical formula 80TeO2–(2 ? x)ZnO–xFe2O3 (x = 0–15 mol%) have been prepared by the melt-quenching method. Elastic and structural properties of the glasses were investigated by measuring both longitudinal and shear velocities using the pulse-echo overlap method at 5 MHz and Fourier transform infrared (FTIR) spectroscopy, respectively. Both longitudinal and shear velocity showed a large increase of 3.40% and 4.68%, respectively, at x = 5 mol% before a smaller increase for x > 5 mol%. Interestingly, longitudinal modulus (L), shear modulus (G), bulk modulus (K) and Young's modulus (E) recorded similar trends with increase in Fe2O3. The initial large increases in shear and longitudinal velocity and related elastic moduli observed at x = 5 mol% are suggested to be due to structural modification which enhances rigidity of the glass network. FTIR analysis showed increase in bridging oxygen (BO) as indicated by the relative intensity of the TeO4 assigned peaks and increase in intensity of the FeO6 assigned peak (~ 451 cm? 1) which indicates that Fe acts as a modifier in the glass network. The increase in rigidity of the glass system is suggested to be due to the increase of BO together with the formation of strong covalent FeO bond. Quantitative analysis based on the bulk compression and ring deformation models showed that the kbc/kexp value decreased gradually from 2.41 (x = 0 mol%) to 2.02 (x = 15 mol%) which infers that the glass system became a relatively more open 3D network as Fe2O3 was increased. 相似文献
19.
B.B. Das 《Journal of Non》2009,355(31-33):1663-1665
Synthesis of the xCuO–(1 ? x)Bi2O3 (0.5 ? x ? 0.9) (C1–C5: x = 0.5, 0.6, 0.7, 0.8, 0.9) glasses was done via nitrate–citrate gel route. Glassy phase is ascertained by XRD studies. Magnetic susceptibility results in the range 4.2–400 K show weak paramagnetic nature with exchange integrals ~0.024–0.13 eV in the glasses. The electron paramagnetic resonance (EPR) in the range 4.2–363 K shows g ≈ 2.0 and the trend of the g-matrix elements g|| > g⊥ > ge for the glasses C1–C5 at 4.2 K are due to the Cu2+ (3d9) paramagnetic site in the glasses which is in a tetragonally elongated octahedron [O1/2–CuO4/2–O1/2] having D4h symmetry. IR spectroscopic results show the presence of octahedron [BiO6/2]3? and [CuO6/2]4? units and pyramidal [BiO2/2O]? unit in the glasses. 相似文献