Macroscopic resonant tunneling of magnetic flux

We have developed a quantitative theory of resonant tunneling of magnetic flux between discrete macroscopically distinct quantum states in SQUID systems. The theory is based on the standard density-matrix approach. Its new elements include the discussion of the two different relaxation mechanisms that exist for the double-well potential, and description of the ``photon-assisted'' tunneling driven by external rf radiation. It is shown that in the case of coherent flux dynamics, rf radiation should lead to splitting of the peaks of resonant flux tunneling, indicating that the resonant tunneling is a convenient tool for studying macroscopic quantum coherence of flux.Comment: 11 pages, 8 figure

High purity AlGaAs grown by molecular beam epitaxy

We report the growth and photoluminescence study of very high quality AlxGal-xAs layers grown by molecular beam epitaxy over the 0<x<0.38 composition range. Heterostructure doped-channel FET's (DCFET's) manufactured using pseudomorphic AlGaAs/InGaAs/GaAs heterostruc-tures containing such a layer have produced an output power of about 1 W/mm with 7.8 dB small signal gain and 60 % power-added efficiency at 18 GHz

Influence of nature of filling of impression cavity on stresses in die and forging

Translated from Russian (Izv. Vyssh. Uchebn. Zaved., Chern. Metall. 1986 (5) p. 94-97)SIGLEAvailable from British Library Document Supply Centre- DSC:5828.4(M--36978)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo