Better heat dissipation effect can be simply and effectively achieved by adding a thin wall orifice in the heat dissipation tube.

Objective To observe pharyngeal orifice of eustachian tube in otitis media with effusion (OME) by using endoscope examination and assess its etiology and clinical therapy.

In this paper an experimental investigation on a recently developed two stage double inlet pulse tube refrigerator with a minor orifice is introduced.