Three-omega technique

Fig. 5.10.5 Three-omega technique the calculated normalized slope (d(AT)/d (log /)) of the thermal oscillation amplitude AT as a function of frequency/for a 100 nm thick aluminum heater element on a 500 nm thick Si02 layer and a 1 mm thick silicon substrate is shown as a function of thermal oscillation frequency/ With increasing frequency, the thermal wave penetrates deeper, allowing different sections of a (multilayered) sample to be scanned...

Fig. 5.10.6 Three-omega-technique influence of different thermal conductivities on the calculated normalized slopes (d(AT)/ d (log/))) for 500 nm thick Si02 films (substrate 0.5 mm silicon, heater 100 nm aluminum)...

Omega seals, thin flexible carbon or stainless steel strips,were welded over the horizontal joints between the tie straps to form a gas seal. The carbon steel omega seals at the three old reactors have rusted and permit gas leakage. A foaming technique is being tried to stop the gas leaks. 

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