[en] This work devoted to a new generalized model of Kapitza conductance. At present, the problem of the development of the theory of contact resistances between solids is particularly relevant due to growth of nanotechnology, where it plays an important and sometimes main role in the heat transport. Presented model takes into all specified properties of acoustic waves. First of all, it is refraction and reflection of acoustic waves that caused simultaneously both longitudinal and transverse waves. Secondly, it is considered the phenomenon of total internal reflection, which makes a significant contribution to the Kapitza resistance. These facts totally change the formulation of the problem, especially, the boundary conditions on the contact surface (interface). Results shows a good agreement with the experimental data, better than in previous works. (paper)

[en] Explicit analytical expressions of the microscopic conduction (gradient or flux) fields in the d-dimensional ($d=2,3$) multi-coated sphere assemblages under the imposed macroscopic gradient and flux fields are presented. Limiting procedures are developed to derive the results for most important specific composites, which include the inclusion composites with highly conducting imperfect interface, lowly conducting (with Kapitza resistance) imperfect interface, general imperfect interface, and those with anisotropic coatings. When the volume proportion of the outermost shells of the assemblages approaches 1, the simplified results for the dilute suspensions of the complex spherically symmetric inclusions in a major matrix are deduced.

[en] We present the analog of te Khalatnikov theory for the Kapitza conductance h/sub kappa/ at the boundary between two dissimilar classical one-dimensional harmonic chains of atoms. We then perform steady-state molecular-dynamics computer experiments to determine h/sub kappa/ directly. The phonon mismatch theory gives only order of magnitude agreement with the computer experiments. Preliminary calculations indicate that anharmonicity increases the Kapitza conductance

No abstract available

[en] We study theoretically the magnetic Kapitza conductance at the interface between superfluid liquid ³He (in its A and B phases) and paramagnetic substances when the heat transfer across the interface is mostly due to magnetic couplings (either of contact or dipolar type) between the nuclear spins of ³He and the electronic spins of the paramagnetic substance. We predict that very close to the transition temperature the value of the Kapitza conductance should be higher when ³He is in one of its superfluid phases than it would be if ³He could remain in its normal phase at the same temperature; on the other hand at lower temperatures the Kapitza-conductance value drops sharply compared to what it would be in a normal rate at the same temperature

[en] The history of dilution refrigeration is traced back to 1951 when London (Proc. Int. Conf. Low Temp. Phys., Oxford (Clarendon Laboratory) p157 (1951)) suggested the possibility of cooling by mixing He³ and He⁴. The first dilution and cascade refrigerators are described, followed by continuous refrigerators and Leyden dilution refrigeration. Finally the Kamerling Onnes Laboratory Pomeranchuk cooling device is considered. (author)

[en] A summary of Kapitza resisitance-influenced heat transfer at cryo-temperatures is presented with emphasis on the coolant He-4 in various states and solid-solid systems below 10 K. Low entropies and ordering processes on a macroscopic scale in superfluid He II provide access to new heat transfer modes of convective and radiative transport. The latter have an impact in conjunction with oscillatory, low-energy modes (acoustic phonons) of solid state lattices. Aside from numerical information on low temperature Kapitza resistance-related heat transfer modes, anomalies including transients are stressed which constitute recognizable departures from classical behavior observed at room temperature and above. 152 references

[en] The effect of slow excitation-relaxation processes on the temperature Kapitza discontinuity at a superconductor-dielectric interface is theoretically considered at heat fluxes that are not small, when the deviations of the distribution functions from equilibrium are not small and the equations cannot be linearized. Expressions are obtained for the temperature discontinuity as a function of the heat flux. It is shown that the absolute value of the Kapitza discontinuity changes when the heat flux changes direction

[en] Thermal cycling of the lattice temperature was used to determine the nuclear spin lattice relaxation of ¹⁹¹sup(m)IrFe in polarizing fields of 0.05 to 1.3 T. At low temperatures, the relaxation time is not very much shorter than the lifetime of ¹⁹¹sup(m)Ir. In the first part of the paper the master equation formalism is extended to include a finite lifetime. Our result for the reduced relaxation constant, γ²Csub(K) = (1.48 +- 0.11) x 10¹⁴K s^-1T^-2 (high field limit) is in serious disagreement with that of a spin echo measurement of ¹⁹³IrFe, but fits much better into the general systematics. A comparison of ralaxation rates for 3d-, 4d-, and 5d-impurities in Fe is given. As a by-product, a Kapitza conductivity constant of lsub(K) = 1.5 mWcm^-2K^-4 +- 30% was found between Fe and dilute ³He⁴He. (orig.)

[en] Our research for the past year was focused on the interaction of spin-polarized atomic hydrogen with helium surfaces, compression of H to high density, a study of Kapitza resistance, and lifetimes in magnetic traps