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1.
L. T. Denisova L. A. Irtyugo Yu. F. Kargin V. V. Beletskii N. V. Belousova V. M. Denisov 《Inorganic Materials》2018,54(2):167-170
The Sm2Ge2O7 and Eu2Ge2O7 germanates have been prepared by solid-state reactions via multistep firing of stoichiometric mixtures of Sm2O3 (Eu2O3) and GeO2 in air at temperatures from 1273 to 1473 K. The molar heat capacity of the samarium and europium germanates has been determined by differential scanning calorimetry in the range 350–1000 K and the C p (T) data have been used to evaluate their thermodynamic properties. 相似文献
2.
L. T. Denisova Yu. F. Kargin L. A. Irtyugo N. V. Belousova V. V. Beletskii V. M. Denisov 《Inorganic Materials》2018,54(12):1245-1249
3.
P. G. Gagarin A. V. Tyurin V. N. Guskov G. E. Nikiforova K. S. Gavrichev A. V. Shlyakhtina 《Inorganic Materials》2017,53(1):86-92
The low-temperature heat capacity of Dy2O3 · 2ZrO2 and Ho2O3 · 2ZrO2 has been determined by adiabatic calorimetry in the temperature range 10–340 K. The results have been used to calculate the entropy, enthalpy increment, and reduced Gibbs energy of the zirconates without taking into account their low-temperature magnetic transformations. 相似文献
4.
V. N. Skrobot V. L. Ugolkov R. G. Grebenshchikov V. V. Gusarov 《Inorganic Materials》2005,41(8):840-844
The Dy2O3-Rh2O3 system is studied by thermal analysis, x-ray diffraction, and chemical analysis of annealed and quenched samples. The results are used to construct a schematic subsolidus phase diagram of the system. Only one double oxide, DyRhO3, is obtained. Some of its physicochemical properties are reported.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 8, 2005, pp. 960–965.Original Russian Text Copyright © 2005 by Skrobot, Ugolkov, Grebenshchikov, Gusarov. 相似文献
5.
L. T. Denisova L. A. Irtyugo Yu. F. Kargin V. M. Denisov V. V. Beletskii 《Inorganic Materials》2017,53(5):510-513
Yb2Sn2O7 and Lu2Sn2O7 have been prepared by solid-state reactions, by firing mixtures of Yb2O3 or Lu2O3 and SnO2 at 1473 K, and the molar heat capacity of these compounds (pyrochlore structure) has been determined by differential scanning calorimetry. The C p (T) data have been used to evaluate the thermodynamic properties of the stannates: enthalpy increment, entropy change, and reduced Gibbs energy. 相似文献
6.
A. V. Shlyakhtina S. N. Savvin A. V. Levchenko I. V. Kolbanev O. K. Karyagina L. G. Shcherbakova 《Inorganic Materials》2008,44(3):299-304
Ho2Ti2O7 and LnYTi2O7 (Ln = Dy, Ho) pyrochlores have been synthesized using hydroxide coprecipitation, mechanical activation, and firing at 1600°C. The bulk and grain-boundary components of their conductivity have been determined for the first time by impedance spectroscopy. The 740°C bulk conductivity of Ho2Ti2O7 is 4 × 10?4 S/cm, and that of HoYTi2O7 is 1 × 10?3 S/cm, with activation energies E a = 1.01 and 1.17 eV, respectively, suggesting that these materials are new oxygen-ion conductors. The bulk conductivity of DyYTi2O7 (3 × 10?4 S/cm at 740°C, E a = 1.09 eV) is almost one order of magnitude lower than that of HoYTi2O7 (1 × 10?3 S/cm at 740°C, E a = 1.17 eV). 相似文献
7.
Critical analysis of experimental and theoretical data on the structure and vibrational frequencies of GeO2, Ge2O2, and Ge3O3 molecules is performed. The values of molecular constants are chosen, and thermodynamic functions in the rigid rotator–harmonic oscillator approximation are calculated in temperature interval Т = 298.15–3000 K. The values obtained are introduced into the data base of the IVTANTERMO program complex. 相似文献
8.
L. T. Denisova L. A. Irtyugo Yu. F. Kargin V. V. Beletskii V. M. Denisov 《Inorganic Materials》2016,52(6):584-586
Gd2Sn2O7 gadolinium stannate with the pyrochlore structure has been prepared by solid-state reaction and its high-temperature heat capacity has been determined by differential scanning calorimetry in the temperature range 350–1020 K. The Cp(T) data are shown to be well represented by the classic Maier–Kelley equation. The experimental Cp(T) data have been used to evaluate the thermodynamic functions of gadolinium stannate: enthalpy increment H°(T)–H°(339 K), entropy change S°(T)–S°(339 K), and reduced Gibbs energy Ф°(Т). 相似文献
9.
Zh. I. Sagintaeva Sh. B. Kasenova S. T. Edil'baeva S. Zh. Davrenbekov B. K. Kasenov E. S. Mustafin E. K. Zhumadilov 《High Temperature》2005,43(5):796-799
The method of dynamic calorimetry is used to investigate the heat capacity of chromite NdLiCr2O5 in the temperature range from 298 to 673 K. A λ-like peak is observed at 523 K.The equations of temperature dependence of the heat capacity of this chromite are derived.The temperature dependences of the thermodynamic functions are calculated.The results of electrophysical investigations indicate that this compound may be classed with semiconductors. 相似文献
10.
L. T. Denisova Yu. F. Kargin N. V. Belousova N. A. Galiakhmetova V. M. Denisov 《Inorganic Materials》2018,54(9):920-924
Polycrystalline HoBiGeO5 and ErBiGeO5 samples have been prepared by solid-state reactions, by firing stoichiometric mixtures of Ho2O3 (Er2O3), Bi2O3, and GeO2. The effect of temperature on the heat capacity of the synthesized compounds has been investigated by differential scanning calorimetry in the range 350–1000 K. The experimental Cp(T) data have been used to evaluate the thermodynamic functions of bismuth holmium and bismuth erbium germanates: enthalpy increment, entropy change, and reduced Gibbs energy. 相似文献
11.
Semiconducting glasses of the Fe2O3-Bi2O3-K2B4O7 system were prepared by the press-quenching method and their dc conductivity in the temperature range 223–393 K was measured. The glass transition temperature values (Tg) of the present glasses were larger than those of tellurite glasses. This indicates a higher thermal stability of the glass in the present system. The density for these glasses was consistent with the ionic size, atomic weight and amount of different elements in the glasses. Mössbauer results revealed that the relative fraction of Fe increases with increasing Fe2O3 content. Electrical conductivity showed a similar composition dependency as the fraction of Fe. The glasses had conductivities ranging from 10 to 10 Scm at temperatures from 223 to 393 K. Electrical conduction of the glasses was confirmed to be due to non-adiabatic small polaron hopping and the conduction was primarily determined by hopping carrier mobility. 相似文献
12.
O. N. Gorshkov Yu. A. Dudin V. A. Kamin A. P. Kasatkin A. N. Mikhaylov V. A. Novikov D. I. Tetelbaum 《Technical Physics Letters》2005,31(6):509-512
We have studied the photoluminescence (PL) of GeO2 and 90 mol % SiO2-10 mol % GeO2 films synthesized by method of RF magnetron sputtering and then irradiated with silicon ions and annealed. The PL of silicon-implanted
GeO2 films, related to the presence of Si nanocrystals (nc-Si), was observed for the first time. It is established that the transformation
of the defect centers responsible for the PL in the spectral range 350–600 nm, as well as the formation of nc-Si emitting
in the region of 700–800 nm, significantly depend on the matrix type. In particular, the PL intensity at 700–800 nm in 90
mol % SiO2-10 mol % GeO2 films is weak. The role of the isovalent substitution of Si and Ge atoms in the transformation of defect centers and the
formation of nc-Si is discussed. 相似文献
13.
N. V. Moiseev P. A. Popov V. D. Solomennik A. I. Zaitsev A. V. Cherepakhin 《Inorganic Materials》2012,48(5):504-507
The heat capacity of a strontium tetraborate (SrB4O7) single crystal has been determined in the temperature range 55–300 K by adiabatic calorimetry, and its Debye characteristic
temperature, entropy change, enthalpy increment, and phonon mean free path have been calculated as functions of temperature. 相似文献
14.
V. M. Chumarev V. P. Mar’evich A. V. Larionov A. Ya. Dubrovskii 《Inorganic Materials》2011,47(3):267-272
Reactions of vanadium, niobium, and tantalum pentoxides with aluminum nitride have been studied using X-ray diffraction. At
temperatures from 1000 to 1600°C, we have identified various V, Nb, and Ta nitrides. The composition of the niobium and tantalum
nitrides depends on the reaction temperature. The tendency toward nitride formation becomes stronger in the order V2O5 < Ta2O5 < Nb2O5. 相似文献
15.
The short-circuit thermally stimulated depolarization current (TSDC) through lead germanate single crystals has been measured
as a function of temperature (100–800 K) and time. The results indicate that poling of the crystals at elevated temperatures
(t ≥ 150°C) produces an electret state related to the spacecharge mechanism of polarization. Relatively mild poling conditions
(E = 0.75 kV/cm, t = 150°C) produce a well-defined, long-lived electret with an abnormally large electret charge (1400 μC/cm2). The electret discharge leads to heating of the crystal, in the form of a peak in the range 520–570 K, whose height exceeds
that of the pyroelectric peak near T
C by two to three orders of magnitude. From the TSDC data, we evaluated the stored electret charge, its density, and the activation
energy of traps for electret charges, and made preliminary conclusions as to the nature of the traps. We demonstrate that
neglect of the electret discharge current (which depends on a number of factors) when determining the pyroelectric coefficient
p
σ above 280 K leads to a significant scatter in data. 相似文献
16.
Theory of deformation twinning by Bilby and Crocker is applied to calculate the twinning elements for all possible twinning modes in monoclinic Er2Si2O7 TYPE C and TYPE D. The magnitude of shear strain was also calculated for each twinning mode. The criteria of small shear strain and minimum shuffling is applied to predict the operative twinning mode for monoclinic Er2Si2O7 TYPE C and TYPE D. These predications of the theory are compared with the available experimental information and may act as guideline for future experimental work. 相似文献
17.
Platelike Li1 ? x Na x Cu2O2 single crystals up to 2 × 10 × 10 mm in dimensions have been grown by slowly cooling (1 ? x)Li2CO3·xNa2O2·4CuO melts in alundum crucibles in air. Li1 ? x Na x Cu2O2 solid solutions in the LiCu2O2-NaCu2O2 system have been shown to exist in the composition range 0.78 < x < 1. The temperature stability ranges of NaCu2O2 and LiCu2O2 are 780–930 and 890–1050°C, respectively. The Mössbauer spectra and electrical conductivity of the crystals have been measured. 相似文献
18.
A procedure has been developed for the synthesis of MgAl2O4 nanopowders with a characteristic particle size of 10–40 nm. Translucent hydrous xerogels have been synthesized as precursors
to MgAl2O4. The synthesized magnesium aluminum spinel nanopowders are promising for the fabrication of optical ceramics. 相似文献
19.
N. N. Chudinova E. V. Murashova A. B. Ilyukhin V. A. Tarnopol’skii A. B. Yaroslavtsev 《Inorganic Materials》2005,41(1):69-72
KFe H2P2O7)2 is synthesized at 443 K in molten polyphosphoric acids containing K and Fe ions, and its crystal structure is determined: triclinic unit cell with a = 4.9974(6) Å, b = 7.4766(9) Å, c = 7.8185(9) Å, = 82.29(2)°, = 83.37(2)° , = 74.13(2)° ; Z = 1, sp. gr. P
. The structure is made up of infinite ribbons formed by corner-shared PO4 tetrahedra and FeO6 octahedra, with the K atoms in between. Neighboring ribbons are linked by hydrogen bonds. The proton conductivity of potassium iron(III) dihydrogen diphosphate is rather low.Translated from Neorganicheskie Materialy, Vol. 41, No. 1, 2005, pp. 74–77. Original Russian Text Copyright © 2005 by Chudinova, Murashova, Ilyukhin, Tarnopolskii, Yaroslavtsev. 相似文献
20.
A. V. Uschakov I. V. Karpov A. A. Lepeshev 《Journal of Superconductivity and Novel Magnetism》2017,30(2):311-316
Ferrite nanoparticles (Fe3O4) have been produced by the direct low-pressure plasma-chemical synthesis. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), vibration magnetometry (VSM), and Mössbauer spectroscopy (NGR) were used for measurements, showing that the produced nanoparticles have an average size of 9.4 nm, a crystalline phase of magnetite, possess a property of superparamagnetism at room temperature, and have a blocking temperature of 89 K. The peculiarities of nanoparticle behavior in the magnetic field, related to a large specific surface area, are discussed. 相似文献