过去分词
发表于 2025-3-30 12:18:09
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
INCUR
发表于 2025-3-30 14:57:30
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
Fibrillation
发表于 2025-3-30 16:43:29
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用肘
发表于 2025-3-30 23:43:17
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SHOCK
发表于 2025-3-31 02:44:19
Interference Effect of Boundaries. Complex Sound Paths and Screen Patterns becoming very complicated and interpretation of the screen picture more difficult. The principles of wave propagation discussed in Chapter 2 will therefore be applied to a few frequently occurring cases.
handle
发表于 2025-3-31 08:54:19
Testing by Means of Transverse, Surface and Plate Wavesinal waves their chief advantage here is that if incident at angles greater than 33° in steel (30° in aluminium) they are totally reflected without being split. In such specimens they can therefore travel long distances provided the roughness of the surface is small compared with the wave length so
ACRID
发表于 2025-3-31 09:41:20
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
Occupation
发表于 2025-3-31 15:03:36
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可耕种
发表于 2025-3-31 20:46:15
Piezoelectric Methods of Generation and Reception of Ultrasonic Wavesre referred to in materials testing as a .,or transducer, and where applicable as a transmitting probe or a receiving probe. We shall now discuss its mode of operation, which is based almost exclusively on the piezoelectric effect. Other methods for generating ultrasonics are discussed in Chapter 8.
Supplement
发表于 2025-3-31 23:54:47
Testing by Means of Transverse, Surface and Plate Wavesthat losses by scatter reflections do not occur. The effect of surface roughness, however, decreases as the angle of incidence becomes larger. In addition the amplitude decreases only according to the law of distance (divergence of beam) and the attenuation of the material for transverse waves.