We have measured the thermal conductivity tensor of a twinned YBa 2 Cu 3 O 7Ϫx single crystal as a function of angle between the magnetic field applied parallel to the CuO 2 planes and the heat current direction, at different magnetic fields and at Tϭ13.8 K. Clear fourfold and twofold variations in the field-angle dependence of xx and xy were, respectively, recorded in accordance with the d-wave pairing symmetry of the order parameter. The oscillation amplitude of the transverse thermal conductivity xy 0 was found to be larger than the longitudinal one, xx 0 , in the range of magnetic field studied here (0 TрBр9 T). From our data we obtain quantities that are free from nonelectronic contributions, and they allow us a comparison of the experimental results with current models for the quasiparticle transport in the mixed state.

We report on the magnetic field (0T≤ B ≤ 9T) dependence of the longitudinal thermal conductivity κ(T, B) of highly oriented pyrolytic graphite in the temperature range 5 K ≤ T ≤ 20 K for fields parallel to the c−axis. We show that κ(T, B) shows large oscillations in the high-field region (B > 2 T) where clear signs of the Quantum-Hall effect are observed in the Hall resistance. With the measured longitudinal electrical resistivity we show that the Wiedemann-Franz law is violated in the high-field regime.

We have measured the transverse thermal conductivity kappa(xy) of twinned and untwinned YBa(2)Cu(3)O(7) single crystals as a function of angle theta between the magnetic field applied parallel to the CuO(2) planes and the heat current direction. For both crystals we observed a clear twofold variation in the field-angle dependence of kappa(xy)(theta) = -kappa(0)(xy)(T,B)sin(2 theta). We have found that the oscillation amplitude kappa(0)(xy) depends on temperature and magnetic field. Our results show that kappa(0)(xy) = aBln(1/bB) with the temperature- and sample-dependent parameters a and b. We discuss our results in terms of Andreev scattering of quasiparticles by vortices and a recently proposed theory based on the Doppler shift in the quasiparticle spectrum.

We report an experimental study of the temporal and spatial dynamics of shock waves, cavitation bubbles, and sound waves generated in water during laser shock processing by single Nd:YAG laser pulses of nanosecond duration. A fast ICCD camera (2 ns gate time) was employed to record false schlieren photographs, schlieren photographs, and Mach-Zehnder interferograms of the zone surrounding the laser spot site on the target, an aluminum alloy sample. We recorded hemispherical shock fronts, cylindrical shock fronts, plane shock fronts, cavitation bubbles, and phase disturbance tracks.

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