19-1 Properties of Sound waves 19-2 Traveling sound waves 19-4 Power and intensity of sound waves 19-3* The speed of sound 19-5 Interference of sound waves 19-6* Standing longitudinal waves 19-7* Vibrating system and sources of sound 19-8 Beats 19-9 The Doppler effect

• Pressure fluctuations • Sound speed • Sound intensity • Standing sound waves---organ pipe • Resonance • Beat • Doppler effect • Shock waves

Auscultation normal breath sound vesicular breath sound bronchial breath sound bronchovesicular breath sound

The speed of sound Sound waves are longitudinal mechanical waves that can travel through solids, liquids, or gases. The speed of a sound wave in medium(having bulk modulus(容变弹性模量)and density p) is:

Part 1 The importance of phonetic study 1)Phonetics is the science of speech sounds. It deals with the sound system of a language. A language consists of three important elements, namely, speech sounds, vocabulary and grammar. Speech sound is the material form on which word and grammar rely for existence. Divorced from speech sound, word and grammar are non-existent. So the first

202.The length of a sound is the length of time during which it is held on continuously in a given word or phrase. The principal facts concerning length in English are given in the following rules: 203. Length of vowels 1.English vowels [i:], are longer than the other English vowels in similar context,i.e when surrounded by the same sounds, and pronounced with the same degree of stress Thus the vowels in bead

The length of a sound is the length of time during which it is held on continuously in a given word or phrase. The principal facts concerning length in English are given in the following rules: 203. Length of vowels 1. English vowels /i:/, /a: / /:/, /u:/, /a: /are longer than the other English vowels in similar context, i.e., when surrounded by the same sounds, and pronounced with the same degree of stress. Thus

In addition to the 'pure vowels' (ones where the tongue positioning is fairly static) shown above there is also the set of vowel diphthongs. These are effectively long vowels during which the tongue moves to produce a definite change of quality during the sound. In phonetic transcription we usually use a pair of linked symbols for each diphthong - one indicating the quality of the sound at the start of the vowel, and the other indicating its quality as it ends. Examples of diphthongs are found in words like 'boy', 'hear', 'may', 'my

1. Standards and Calibration 2. Basic Methods of Pressure Measurement 3. Deadweight Gages and Manometers 4. Elastic Transducers 5. Vibrating-Cylinder and Other Resonant Transducer 6. High-Pressure Measurement 7. Low-Pressure (Vacuum) Measurement 8. Sound Measurement

In the production of a sound, if the air, onceout of the glottis, is allowed to pass freelythrough the resonators, the sound is a vowel