有恶意
发表于 2025-3-28 17:18:59
Introductionspace knows no sound because it is the particles of matter themselves which vibrate, in contrast for instance to the oscillations of light or other electromagnetic waves where the electric and magnetic state of the space oscillates. In air a sound wave moves a discrete volume of air back and forth a
称赞
发表于 2025-3-28 21:27:29
Wavesanical wave is composed of oscillations of discrete particles of material. The motion carried out by a small mass attached to a spring as shown in Fig. 1.1 if pulled down once and released, is called an oscillation. Left to itself, the mass oscillates about the equilibrium position. The nature of th
衍生
发表于 2025-3-29 02:26:18
http://reply.papertrans.cn/95/9406/940566/940566_43.png
引导
发表于 2025-3-29 05:07:08
Geometric Ultrasonic Opticsvery clear presentation, e.g. of the effect of mirrors and lenses with curved surfaces. Also we have already used this convenient method, e.g. when discussing reflection and refraction in Chapter 2. In this connection it should, however, not be overlooked that this method fails to take into account
傲慢物
发表于 2025-3-29 10:15:54
Wave Physics of Sound Field. The Sound Beam a plate which transmits to the particles of the contiguous material its own longitudinal or transverse motion, viz. over its entire surface with the same phase and amplitude. If such an oscillator is mounted in an extended, rigid wall whence it radiates into a liquid, a sound field is obtained simi
Wallow
发表于 2025-3-29 12:55:23
http://reply.papertrans.cn/95/9406/940566/940566_46.png
揭穿真相
发表于 2025-3-29 16:33:37
Attenuation of Ultrasonic Waves in Solidss show no attenuation whatever of the sound pressure along its path, and a spherical wave, or the sound beam of a probe in the far-field, would merely decrease inversely with the distance from the source. Natural materials, however, all produce a more or less pronounced effect which further weakens
你敢命令
发表于 2025-3-29 23:44:27
Piezoelectric Methods of Generation and Reception of Ultrasonic Waveson except that they are excited in the material concerned by the contact face of a . which oscillates with the desired waveform and frequency. For detection a . has been assumed which likewise has a contact face and which is capable of measuring the sound pressure of an incident wave. Both devices a
ASSET
发表于 2025-3-30 00:50:53
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
STEER
发表于 2025-3-30 04:42:25
http://reply.papertrans.cn/95/9406/940566/940566_50.png