PT Unknown AU Smirnov, AV Larionov, PA Finkel, MI Maslennikov, SN Voronov, BM Gol'tsman, GN TI NbZr films for THz phonon-cooled HEB mixers SE Proc. 19[super:th] Int. Symp. Space Terahertz Technol. PY 2008 BP 44 EP 47 DE HEB; NbZr; material search PI Groningen, Netherlands ER