In the first half of this paper, free vibration of a conical solid horn is analyzed two-dimensionally and axisymmetrically by measns of the F. E. M. . From the results analyzed, the geometry of the horns is determined whose diameter of thick end is larger than quater wave-length. In addition, a double conical horn, which is formed by connecting two conical horns together, is examined on the influence of its combinations and its connecting parts. In the latter of this paper, the ratio outside and inside diameter of the flange which causes each resonance of the supporting flange is determined by means of the analytical solution. The F. E. M. analyzes free vibration of a system formed by a horn and a flange, and the results analyzed prove the rightness of this analytical solution.
Acoustical properties of impact sound generated by the standard tapping machine can simply be characterized by two factors the maximum band level and the center frequency concerned with it, since the spectra of impact sound obtained in various cases of floor structures are very similar to each other. A method based on this principle for analyzing and evaluating the impact sound insulation of floors is studied theoretically. It is found that the pair of the values of L_C and L_A which can be measured with a sound level meter is also applicable for analyzing the acoustical factors above mentioned. A graphic method where a certain pair of values of L_C and L_A locates a point is convenient for evaluating the results obtained in field measurements and assessing the impact sound insulation of floors. Assuming the standardized spectrum pattern of impact sound, it is possible to draw the contour lines for rating on this diagram according to any existing standard which needs the frequency analysis of impact sound generated by the standard source.
When a vibration pickup is set directly on a surface of a vibrating body, the system has a resonant frequency caused by the mass of pickup and the contact compliance of the setting point. The resonant frequency places restrictions on a measurement frequency range, and causes errors in measurement. This paper is intended to indicate the characteristics of the horizontal resonant frequency. THe horizontal resonant frequency is always lower than the resonant frequency in the vertical direction and is affected more sensitively by the condition of setting points. Furthermore, it is proved graphically that the height of center of gravity and contact areas of pickup have a considerable effect upon the horizontal resonant frequency.
In order to find good bonding materials applicable to the ultrasonic delay line operating over a wide temperature range, acoustic properties of five different bonding materials which are capable of bonding in the range of room temperature and can be used at the frequency of up to 100MHz, are investigated experimentally. By using the ultrasonic delay lines composed of LiNbO_3 or Y-cut quartz transducers, a fused quartz rod, and the bonding materials to be investigated, influence of bonding masterials on insertion loss is measured as a function of temperature by means of the pulse-echo method. The insertion loss of indium bonds which are applied by an ultrasonic bonding technique at room temperature is flat over the temperature range between -170^oC and 100^oC. It is proved that this bonding material is one of the excellent bonding materials capable of appling over a wide temperature range. Furthermore, bonding techniques and available temperature ranges of these materials are described in detail.