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Ermolenko I. N. Krylovich V. I. Alekseenko V. I. Dubkova V. I. Logvinovich P. N. Lyubliner I. P. 《Journal of Engineering Physics and Thermophysics》1982,43(3):992-995
Experimental data are given on the behavior of the velocity of ultrasound and electrical conductivity as a function of the temperature in an epoxy composite material filled with carbon fiber.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 43, No. 3, pp. 413–417, September, 1982. 相似文献
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Santhosh Kumar Matam O. Korsak L. Bocher D. Logvinovich P. Hug A. Weidenkaff D. Ferri 《Topics in Catalysis》2011,54(16-18):1213-1218
Lab scale fixed-bed reactor is applied for operando transmission X-ray absorption spectroscopy (XAS) for structure–activity studies of supported metal oxide catalysts under real reaction conditions. This setup includes many properties of an optimal fixed-bed reactor for operando transmission XAS studies. For instance, it is usable in a wide range of temperature (up to 1,000 °C), pressure and space velocity. Besides, this operando setup can be used for transmission XAS measurements in a wide edge energy range. The potential of this reactor for operando transmission XAS is demonstrated by, as examples, the three-way catalytic performance of Pd/Al2O3/CeZrO2 and Rh/Al2O3. 相似文献
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V. I. Alekseenko V. I. Krylovicb P. N. Logvinovich V. V. Mikhal'kov 《Measurement Techniques》1994,37(9):994-997
An analysis is made of dynamic measurement methods, based on utilizing parametric frequency shift effects, which propose the use of a transducer in the form of a linear four-terminal network.Translated from Izmeritel'naya Tekhnika, No. 9, pp. 15–17, September, 1994. 相似文献
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V. R. Sobol’ P. N. Logvinovich S. E. Bel’skii A. V. Blokhin 《Journal of Engineering Physics and Thermophysics》2007,80(4):840-846
The influence of microplasticity caused by the motion of dislocation segments on the propagation of elastic vibrations in
structural materials is considered. It is shown that the character of motion of a dislocation segment exerts its effect on
the propagation velocity of an acoustic wave. This fact should be taken into account when nonstationary frequency-phase methods
of measuring the physical parameters of a medium are used.
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Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 4, pp. 193–199, July–August, 2007. 相似文献
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Rosiana Aguiar Dmitry Logvinovich Anke Weidenkaff Helmut Karl Christof W. Schneider Armin Reller Stefan G. Ebbinghaus 《Materials Research Bulletin》2008,43(6):1376-1383
Thin films of LaxSr1−xTiO3+x/2 (x = 0, 0.25, 0.5, 0.75, 1) were grown by laser ablation on two different kinds of substrates (SrTiO3 (STO) and MgO) and were subsequently ammonolysed to yield the corresponding oxynitrides LaxSr1−xTi(O,N)3. For both substrates all films were found to grow epitaxially to the (1 0 0) direction of the cubic perovskite structure, except for x = 0.5 that grew parallel to the (1 1 0) direction. For some of the films TiN was detected as impurity phase. Scanning electron microscopy revealed that the films are dense and homogeneous with thicknesses around 350 nm. Atomic force microscopy showed that the surface roughness of the films varied between 4.2 and 14.1 nm. The employed substrate had a strong influence on the electrical properties. Films grown on STO exhibited a metallic behaviour, in contrast to the films grown on MgO, which were insulating. 相似文献
6.
Myriam H. Aguirre Dmitry Logvinovich Laura Bocher Rosa Robert Stefan G. Ebbinghaus Anke Weidenkaff 《Acta Materialia》2009,57(1):108-115
The high-temperature thermoelectric properties of Sr2RuYO6 and Sr2RuErO6 double perovskites were evaluated and reported for the first time. These compounds show high Seebeck coefficients not only at room temperature, but also at high temperature (for Sr2RuYO6, SRT ≈ ?475 μV K?1 and S1200K ≈ ?250 μV K?1; Sr2RuErO6, SRT ≈ ?400 μV K?1 and S1200K ≈ ?250 μV K?1). The n-type semiconducting behaviour dominates the resistivity values. Both compounds crystallize in a monoclinic unit cell (space group P21/n). The lattice parameters are a = 5.7761(2), b = 5.7804(1), c = 8.1689(1), α = γ = 90° and β = 90.2087(8)° for the Sr2RuYO6, and a = 5.7760(1), b = 5.7722(0), c = 8.1544(4), α = γ = 90° and β = 90.2099(7)° for Sr2RuErO6. The unit cell can be described approximately as √2ap × √2ap × 2ap, where ap is the unit cell parameter of the ideal cubic perovskite structure. High-resolution transmission electron microscopy shows an interesting three-dimensional micro-twin-domain texture where the c axis is placed in the three space directions. Structural transitions at high temperatures (Tt(Sr2RuYO6) ≈920 K and Tt(Sr2RuErO6) ≈890 K) are observed by specific heat measurement in both compounds, which are found to have a strong influence on the Seebeck coefficient and electrical conductivity. 相似文献
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Laura Bocher Myriam H. Aguirre Rosa Robert Dmitry Logvinovich Snejana Bakardjieva Jiri Hejtmanek Anke Weidenkaff 《Acta Materialia》2009,57(19):5667-5680
Polycrystalline perovskite-type CaMn1-xNbxO3 phases (with x=0.02,0.05,0.08 and 0.10) were investigated with regard to their structure, microstructure and thermal stability as a function of temperature. The studied phases revealed a complex microstructure at room temperature with 90° twinned domains. At high temperatures, the manganate phases underwent a structural transition from orthorhombic to cubic symmetry, as confirmed by in situ high-temperature X-ray powder diffraction and electron diffraction data. Thermogravimetric heating/cooling studies showed a reversible thermal reduction/reoxidation process that occurred above a defined transition temperature. A possible mechanism relating the high-temperature structural transition and the thermal reduction process of slightly substituted CaMnO3 phases was proposed. The thermal reduction process resulted in a change in the Mn3+/Mn4+ concentrations in the Mn sublattice, and therefore in a modification of the transport properties. A comprehensive study examined the impact of both phenomena on the electrical and thermal transport properties. 相似文献
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Rosa Robert Dmitry Logvinovich Myriam H. Aguirre Stefan G. Ebbinghaus Laura Bocher Petr Tomeš Anke Weidenkaff 《Acta Materialia》2010,58(2):680-691
The influence of the partial substitution of Co by Ti in the LaCoO3 perovskite system is studied by evaluating the electrical conductivity, the Seebeck coefficient and the thermal conductivity of the compounds up to T = 1273 K. The X-ray diffraction patterns of the LaCo1?xTixO3±δ (0.01 ? x ? 0.5) phases show two structural modifications depending on the Ti content. Compounds with x < 0.3 crystallize in the rhombohedrally distorted perovskite structure while samples with x ? 0.3 possess an orthorhombic unit cell. The oxidation state of the Co ions is studied by X-ray absorption near edge structure (XANES) spectroscopy. A negative thermoelectric power is found in the LaCoO3 system for low level Ti substitution (x = 0.01). In contrast, samples with higher Ti content show a large positive Seebeck coefficient, indicating positive majority charge carriers in the system. The electrical resistivity of the studied materials reveals a semiconducting-like behaviour. The lattice thermal conductivity was found to be low and nearly temperature-independent. The samples exhibit very small crystallite sizes in the range of few nanometres. Therefore, the low thermal conductivity can be assigned to an enhanced phonon scattering on grain boundaries. 相似文献
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