Sound Intensity of High Frequency Noise Source in Dental Clinics.

从职业健康的角度出发，笔者对牙科涡轮机和超声波洁牙机的高频噪声进行了频率分析，在本研究中，笔者采用声强测量的方法，对这些牙科设备的声功率进行了测量，在第一年，我买了一对声音强度测量仪（麦克风）并将其与2通道FFT分析仪连接，建立了一套基于互谱分析的声强测量系统。然后在实验室中模拟牙科空气涡轮机手机的声音，给出了频率为5 ~ 7 kHz的连续声，并绘制了声强矢量图。通过这个初步实验，我发现，如果声源是一个点，如牙科空气涡轮机手机，麦克风的位置影响测量值的关键。我知道我会在测量声音方面做更多的工作 关于我们 强度比我预期的高;第二年，为了进行合理的实验，我利用绘图板制作了一个“网格点移动板”，这样我就可以在60 × 60 cm的范围内测量板上任意网格点的声强矢量。为了实现半自动测量，微机通过GPIB接口对FFT分析仪进行控制，大大节省了多点测量的时间。结果表明，通过频谱分析和声强分析，牙科空气涡轮机手机的声音不仅从手机的旋转部分散射，而且从手柄部分也散射。我很遗憾应该推迟发布牙科设备实际声音的声强测量结果，给我们带来高频噪音。因为我花了很多天的时间来建立上面提到的系统是必要的。应继续进行试验，以达到预期的目的。少

From the viewpoint of occupational health, I have interested in frequency analysis on high frequency noise made by dental air turbine handpieces or ultrasonic scalers in dental clinics.In this study, I would like to measure the sound power from these dental equipments, by means of sound intensity measurement.In the first year, I had purchased a pair of sound intensity measuring devices (microphones) and connected them with a 2-channel FFT analyzer, and I have built a system to measure the sound intensity by using the method of cross spectral analysis. Then, in the laboratory, I gave a continuous sound of which frequency was 5 to 7kHz as mimic sound of dental air turbine handpiece, and illustrated a figure of sound intensity vectors. Through this preliminary experiment, I have found that if a sound source is a point such as dental air turbine handpieces, positioning of the microphones affect the measured value critically. I knew that I would put a greater deal of work in measuring sound … More intensity than I expected ; those are necessity of multi-point measurement, accurate positioning in each grid point, intricate operation of the FFT analyzer severally.The next year, for making rational experiments, I had prepared a 'grid-point moving board' making use of a drafting board, so that I was able to measure sound intensity vector at any grid point on the board in an area of around 60x60cm. For the purpose of realizing semi automatic measurement, the FFT analyzer was controlled by personal computer through GPIB interface, then it saved time for multi point measurement very well. Results show that sounds of dental air turbine handpieces are scattered not only from the rotary part but also from the grip part of the handpiece analyzed by spectral analysis and sound intensity analysis.I regret that I should postpone the publication of the result of sound intensity measurement of actual sound on dental equipments which give us high frequency noise, because it was necessary that I spent many days to build up the system mentioned above. The experiments should be continued to attain the desired end. Less