表被动
发表于 2025-3-23 09:49:47
Other Methods for Transmitting and Receiving Ultrasoundals than obtainable by the piezoelectric effect, they nevertheless offer a number of advantages which in special cases make their application in the testing of materials useful. In the case of many of these effects the energy is transmitted by electrical or magnetic fields which in principle make me
光滑
发表于 2025-3-23 15:06:28
Intensity Methodstrasonic waves for non-destructive testing. It dates back to 1930 and was originated by Sokolov and Mühlhäuser . The principle is shown in Fig. 9.1 in which the intensity method is portrayed schematically by passing sound through a test plate, at a flawless and alternately at a defective p
啤酒
发表于 2025-3-23 19:19:31
Pulse-Echo Methodder water. A suggestion by Richardson to locate icebergs at some distance by this method found practical realisation through Langevin in locating ships, particularly submarines. In peace time it was used in the form of Behm’s depth sounder for measuring depths at sea, but only during World War II wa
消耗
发表于 2025-3-23 23:02:54
Transit-Time Method a given distance belong to one and the same group. All these methods are used primarily for wall-thickness measurements and for locating flaws in plates and tubes. It is thus logical to combine the pulse methods and the previously separately treated resonance methods which likewise produce a resona
Parley
发表于 2025-3-24 06:09:31
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祖先
发表于 2025-3-24 08:13:57
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DUCE
发表于 2025-3-24 13:43:48
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Inexorable
发表于 2025-3-24 15:44:53
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excursion
发表于 2025-3-24 20:39:43
Interference by External High-Frequency and Ultrasonic Sourcesnce, however, certain remedies of general validity apply. If several adjacent pulse instruments with not exactly identical repetition frequencies are used, the pulses are transmitted from one instrument to the other electrically and they travel over the image. This requires synchronisation of the re
上流社会
发表于 2025-3-25 01:36:49
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