Coherent transport in homojunction between excitonic insulator and semimetal

From the solution of a two-band model, we predict that the thermal and electrical transport across the junction of a semimetal and an excitonic insulator will exhibit high resistance behavior and low entropy production at low temperatures, distinct from a junction of a semimetal and a normal semiconductor. This phenomenon, ascribed to the dissipationless exciton flow which dominates over the charge transport, is based on the much longer length scale of the change of the effective interface potential for electron scattering due to the coherence of the condensate than in the normal state.Comment: RevTeX 4.0, 13 pages, 5 b/w figures, 1 colour figure, 1 table. Version modified with respect to the original, which will appear in Physical Review Letters. This version includes the supplementary (EPAPS) material as an Appendix, and it is slightly longer than the accepted version (more text and references

Electron transport through a mesoscopic metal-CDW-metal junction

In this work we study the transport properties of a finite Peierls-Fr\"ohlich dielectric with a charge density wave of the commensurate type. We show that at low temperatures this problem can be mapped onto a problem of fractional charge transport through a finite-length correlated dielectric, recently studied by Ponomarenko and Nagaosa [Phys. Rev. Lett {\bf 81}, 2304 (1998)]. The temperature dependence of conductance of the charge density wave junction is presented for a wide range of temperatures.Comment: Latex, Revtex 3.0, 7 pages, 2 EPS figures (uses epfs

Thermal Strain Dependencies Characterizing Susceptibility of Steels to Cold Cracking Thermal stress indices that determine cold-cracking probability in low-and medium-a Iloyed steel are in vestigated

ABSTRACT. This article describes the procedure and results of investigation of the main thermal strain indices that determine the probability of cold cracking in welding of low-and medium-alloyed steels. The relationship has been established between the process of intensive relaxation of temporary stresses during structural transformations and initiation of microcracks in cooling under the conditions of welding thermal strain cycle. Parameter M r has been suggested for estimation of steel susceptibility to cold crack formation. Effect of hydrogen on cold cracking is analyzed

Generators in IMPATT-diodes excited by a subharmonic signal

The paper considers various operation conditions of generators in IMPATT-diodes driven with an external signal, whose frequency Ω is considerably lower than the self-oscillation frequency ωso. Characteristics of amplitude-frequency modulation of the output signal are determined when the locking is performed by a signal with its frequency equal to the harmonic nΩ, and the active multiplication of frequency has a high multiplicity factor. The ways to improvement of effectiveness of frequency multiplication modes of operation are outlined

The stucture and mechanical properties explosion-welded joints in mild steel

Translated from Russian (Report of the E O Paton Electric Welding Institute, Kiev, 1999)Available from British Library Document Supply Centre-DSC:9023.190(10113)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo