Pressure measurement in a recovery tube for superhard BN synthesized by explosion

Double π-form gauge pair made of the manganin foil and the constantan foil, with the sensing element being 0.6mm long and 0.15mm wide, is carefully embeded in the different radius R interior BN in the recovery tube. The digitizing oscilloscope TEK 2430A is used for recording the gauge output signals supported by the constant current pulsed-power supply. The pure pressure analogue signals involved in the manganin gauge records are acquired by that the records minus the pure tensile analogue signals involved in constantan gauge records, then the pressure P can be worked out by the use of dynamic piezoresistance function and the tensile coefficient according to the above clue the P-R correlation interior BN in the recovery tube, corresponding to the different explosion-load condition, is measured and the phase transition condition of BN is also given. copyright 1996 American Institute of Physics