The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform

Vladimir E. Fortov - One of the best experts on this subject based on the ideXlab platform.

  • Measurement of the electrical resistivity of hot aluminum passing from the liquid to Gaseous State at supercritical pressure
    Physical Review B, 2005
    Co-Authors: V. N. Korobenko, A. D. Rakhel, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    Thin aluminum foil strips tamped by polished glass plates were rapidly heated by means of a pulse current. The experimental technique has ensured a sufficiently homogeneous heating of the foil samples during continuous expansion from the liquid to Gaseous State at a pressure of 7--60 kbar. Results on the electrical resistivity of aluminum were obtained in a density range extending from about the normal solid density down to a density 30 times less and in a temperature range from 6000 to 50 000 K. A dielectriclike dependence of the resistivity on temperature along isochore was observed at a density, which is 4 times less than the normal solid density. A maximum in the temperature dependence of the resistivity was detected along an isochore corresponding to a density that is 5.4 times less than the normal solid density. Present results confirm recent theoretical predictions based on finite-temperature density-functional theory about the behavior of the electrical resistivity of aluminum in the liquid and Gaseous State.

  • Electrical Conductivity of Tungsten in a Continuous Transition from Condensed to Gaseous State
    International Journal of Thermophysics, 2004
    Co-Authors: A. D. Rakhel, V. N. Korobenko, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    A pulse heating technique is developed that makes it possible to investigate the transition of a metal from a condensed to a Gaseous State while maintaining almost uniform temperature and pressure distributions in a sample. By means of the technique, the electrical conductivity of tungsten was measured in a process during which a pressure in the range of 30–100 kbar was applied to the sample and its density decreased from the standard solid density to a density 15–20 times less. Since the pressures are substantially higher than the critical pressure, the transition from a condensed to a Gaseous State was continuous. Earlier results have shown that along isobars in the range of 30–60 kbar the density dependence of the electrical conductivity changes radically at a certain density value (at which it has a pronounced knee). At the knee, the density is approximately 10 times less than the standard solid density, and the internal energy is about two times the sublimation energy. The dependence of the electrical conductivity near the knee becomes smoother as the pressure increases. In this paper new results on the conductivity of tungsten at the pressures up to 100 kbar are presented. It is shown that the knee becomes remarkably flatter and smoother than the corresponding low pressure dependence. Nevertheless, the main features of the electrical conductivity dependence observed at low pressures persist at the maximum applied pressure.

V. N. Korobenko - One of the best experts on this subject based on the ideXlab platform.

  • Measurement of the electrical resistivity of hot aluminum passing from the liquid to Gaseous State at supercritical pressure
    Physical Review B, 2005
    Co-Authors: V. N. Korobenko, A. D. Rakhel, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    Thin aluminum foil strips tamped by polished glass plates were rapidly heated by means of a pulse current. The experimental technique has ensured a sufficiently homogeneous heating of the foil samples during continuous expansion from the liquid to Gaseous State at a pressure of 7--60 kbar. Results on the electrical resistivity of aluminum were obtained in a density range extending from about the normal solid density down to a density 30 times less and in a temperature range from 6000 to 50 000 K. A dielectriclike dependence of the resistivity on temperature along isochore was observed at a density, which is 4 times less than the normal solid density. A maximum in the temperature dependence of the resistivity was detected along an isochore corresponding to a density that is 5.4 times less than the normal solid density. Present results confirm recent theoretical predictions based on finite-temperature density-functional theory about the behavior of the electrical resistivity of aluminum in the liquid and Gaseous State.

  • Electrical Conductivity of Tungsten in a Continuous Transition from Condensed to Gaseous State
    International Journal of Thermophysics, 2004
    Co-Authors: A. D. Rakhel, V. N. Korobenko, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    A pulse heating technique is developed that makes it possible to investigate the transition of a metal from a condensed to a Gaseous State while maintaining almost uniform temperature and pressure distributions in a sample. By means of the technique, the electrical conductivity of tungsten was measured in a process during which a pressure in the range of 30–100 kbar was applied to the sample and its density decreased from the standard solid density to a density 15–20 times less. Since the pressures are substantially higher than the critical pressure, the transition from a condensed to a Gaseous State was continuous. Earlier results have shown that along isobars in the range of 30–60 kbar the density dependence of the electrical conductivity changes radically at a certain density value (at which it has a pronounced knee). At the knee, the density is approximately 10 times less than the standard solid density, and the internal energy is about two times the sublimation energy. The dependence of the electrical conductivity near the knee becomes smoother as the pressure increases. In this paper new results on the conductivity of tungsten at the pressures up to 100 kbar are presented. It is shown that the knee becomes remarkably flatter and smoother than the corresponding low pressure dependence. Nevertheless, the main features of the electrical conductivity dependence observed at low pressures persist at the maximum applied pressure.

G. A. Voyiatzis - One of the best experts on this subject based on the ideXlab platform.

  • Raman spectroscopic characterization of high temperature MGaCl8 (M = Nb, Ta) dinuclear molecular complexes in the liquid and Gaseous State
    Polyhedron, 1993
    Co-Authors: Soghomon Boghosian, G. A. Voyiatzis
    Abstract:

    Abstract Raman spectra were obtained at temperatures 375–650 K and pressures up to 4 atm from GaCl3-NbCl5 and GaCl3-TaCl5 binary mixtures in the liquid and vapour State. The data indicate formation of NbGaCl8 and TaGaCl8 liquid and vapour dinuclear addition complexes. The spectra were interpreted in terms of a C2ν configuration for the MGaCl8 (M = Nb, Ta) molecules consisting of a MCl6 octahedron sharing an edge with a GaCl4 tetrahedron. A comparison of the spectral features of 1 : 1 GaCl3-NbCl5 and GaCl3-TaCl5 molten mixtures with the spectra of the corresponding polycrystalline samples indicates that the proposed identity for the complexes is maintained in all three phases. The NbGaCl8 and TaGaCl8 complexes exist in the liquid State in a wide temperature range beyond their melting points (125 and 150°C, respectively) and are shown to undergo dissociation to their components [Nb2Cl10(1)/NbCl5(1), Ga2Cl6(1) and Ta2Cl10(1)/TaCl5(1)] with increasing temperature. Both complex molecules are identified in the Gaseous State in low percentages among the vapours of their components and are almost totally decomposed at temperatures higher than ca 325°C. The enthalpy of the reaction TaCl5(g) + 1 2 Ga2Cl6(g) ⇌ TaGaCl8(g) was determined from accurate relative Raman intensity measurements as ΔH0 = −38±2 kJ mol−1.

A. I. Savvatimski - One of the best experts on this subject based on the ideXlab platform.

  • Measurement of the electrical resistivity of hot aluminum passing from the liquid to Gaseous State at supercritical pressure
    Physical Review B, 2005
    Co-Authors: V. N. Korobenko, A. D. Rakhel, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    Thin aluminum foil strips tamped by polished glass plates were rapidly heated by means of a pulse current. The experimental technique has ensured a sufficiently homogeneous heating of the foil samples during continuous expansion from the liquid to Gaseous State at a pressure of 7--60 kbar. Results on the electrical resistivity of aluminum were obtained in a density range extending from about the normal solid density down to a density 30 times less and in a temperature range from 6000 to 50 000 K. A dielectriclike dependence of the resistivity on temperature along isochore was observed at a density, which is 4 times less than the normal solid density. A maximum in the temperature dependence of the resistivity was detected along an isochore corresponding to a density that is 5.4 times less than the normal solid density. Present results confirm recent theoretical predictions based on finite-temperature density-functional theory about the behavior of the electrical resistivity of aluminum in the liquid and Gaseous State.

  • Electrical Conductivity of Tungsten in a Continuous Transition from Condensed to Gaseous State
    International Journal of Thermophysics, 2004
    Co-Authors: A. D. Rakhel, V. N. Korobenko, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    A pulse heating technique is developed that makes it possible to investigate the transition of a metal from a condensed to a Gaseous State while maintaining almost uniform temperature and pressure distributions in a sample. By means of the technique, the electrical conductivity of tungsten was measured in a process during which a pressure in the range of 30–100 kbar was applied to the sample and its density decreased from the standard solid density to a density 15–20 times less. Since the pressures are substantially higher than the critical pressure, the transition from a condensed to a Gaseous State was continuous. Earlier results have shown that along isobars in the range of 30–60 kbar the density dependence of the electrical conductivity changes radically at a certain density value (at which it has a pronounced knee). At the knee, the density is approximately 10 times less than the standard solid density, and the internal energy is about two times the sublimation energy. The dependence of the electrical conductivity near the knee becomes smoother as the pressure increases. In this paper new results on the conductivity of tungsten at the pressures up to 100 kbar are presented. It is shown that the knee becomes remarkably flatter and smoother than the corresponding low pressure dependence. Nevertheless, the main features of the electrical conductivity dependence observed at low pressures persist at the maximum applied pressure.

A. D. Rakhel - One of the best experts on this subject based on the ideXlab platform.

  • Measurement of the electrical resistivity of hot aluminum passing from the liquid to Gaseous State at supercritical pressure
    Physical Review B, 2005
    Co-Authors: V. N. Korobenko, A. D. Rakhel, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    Thin aluminum foil strips tamped by polished glass plates were rapidly heated by means of a pulse current. The experimental technique has ensured a sufficiently homogeneous heating of the foil samples during continuous expansion from the liquid to Gaseous State at a pressure of 7--60 kbar. Results on the electrical resistivity of aluminum were obtained in a density range extending from about the normal solid density down to a density 30 times less and in a temperature range from 6000 to 50 000 K. A dielectriclike dependence of the resistivity on temperature along isochore was observed at a density, which is 4 times less than the normal solid density. A maximum in the temperature dependence of the resistivity was detected along an isochore corresponding to a density that is 5.4 times less than the normal solid density. Present results confirm recent theoretical predictions based on finite-temperature density-functional theory about the behavior of the electrical resistivity of aluminum in the liquid and Gaseous State.

  • Electrical Conductivity of Tungsten in a Continuous Transition from Condensed to Gaseous State
    International Journal of Thermophysics, 2004
    Co-Authors: A. D. Rakhel, V. N. Korobenko, A. I. Savvatimski, Vladimir E. Fortov
    Abstract:

    A pulse heating technique is developed that makes it possible to investigate the transition of a metal from a condensed to a Gaseous State while maintaining almost uniform temperature and pressure distributions in a sample. By means of the technique, the electrical conductivity of tungsten was measured in a process during which a pressure in the range of 30–100 kbar was applied to the sample and its density decreased from the standard solid density to a density 15–20 times less. Since the pressures are substantially higher than the critical pressure, the transition from a condensed to a Gaseous State was continuous. Earlier results have shown that along isobars in the range of 30–60 kbar the density dependence of the electrical conductivity changes radically at a certain density value (at which it has a pronounced knee). At the knee, the density is approximately 10 times less than the standard solid density, and the internal energy is about two times the sublimation energy. The dependence of the electrical conductivity near the knee becomes smoother as the pressure increases. In this paper new results on the conductivity of tungsten at the pressures up to 100 kbar are presented. It is shown that the knee becomes remarkably flatter and smoother than the corresponding low pressure dependence. Nevertheless, the main features of the electrical conductivity dependence observed at low pressures persist at the maximum applied pressure.