| 摘要 |
1276304 Photo-electric testing DERRITRON ELECTRONICS Ltd 19 Nov 1969 [21 Nov 1968] 55264/68 Heading G1A [Also in Division G2] Areas of stress in a specimen 10 vibrated by a table 11 are located by detecting the radiation emanating from different points in its surface due to temperature rises caused by stresses produced by the vibration. The specimen may be photographed for infrared emanation, or it may be scanned by a cryogenically cooled detector 20 through a mirror system 24, 25, 26 the last named of which is motor driven in two directions at right angles to scan the whole area. The detector output may produce a record of temperature such as on a magnetic tape, or may reproduce by C. R. T. a picture of the surface in which the brightness indicates the intensity of radiation emanating from different points, or a picture of intensity graphs produced by successive scan lines. The detector may be a semi-conductor layer on the inner wall of a Dewar flask cooled internally by liquid nitrogen. |
