We report on acoustic impedance control of the acoustic resonator using pneumatic balloon actuators. The fabricated pneumatic balloon actuators at acoustic holes could tune the acoustic resistance and the inertance of the resonator through structural parameter control. This paper focuses on the tuning of the acoustic resistance and the inertance when the acoustic capacitance is fixed. We tried to control not only the resonant frequency but also the total acoustic impedance and the phase. In the experimental results, a slight deformation of actuators could provide a large change of the acoustic impedance in the resonator.

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The experiment to detect the acoustic wave of an audible frequency region in air by a visible laser beam was carried out, showing that the audible waves with relatively long wavelength from 34 mm to 1700 mm could be directly detected by using a diode laser light of 670 nm and 6 mW. The frequency property was measured for each sound pressure from 75 dB to 100 dB and it is shown that the amplitude of output signal is linearly proportional to the sound frequency, which is consistent with the theoretical prediction. Furthermore, property of directivities in the planes vertical and parallel to the optical axis of laser beam propagation and the spatial profiles of the laser diffraction pattern for each incident angle of a sound wave were measured. The directivity property in the vertical plane for each frequency (200Hz to 10kHz) is very similar to each other and the full angle of half-maximum of directivity is about 120°. On the other hand, the directivity in the parallel plane for each frequency is different from each other. The directivity for low frequency is relatively broad. The full angle of half-maximum of directivity for 10 kHz is smallest and about 90°.

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Performance of the IDD, which is one kind of display device, has been improved. The IDD consists of a driving half mirror and a substrate mirror, which construct an interferometer. It is possible for the IDD to create all the colors of the rainbow in only one pixel. To realize the device, a parallel driving and a precise flatness are required for the driving mirror. To solve those problems, a new structure is proposed in this paper. With respect to the new structure, light interference in the pixel is caused by an optical path difference between the driving half mirror suspended by leaf-springs and a floating half mirror isolated electrically by SiO₂ layers. The driving mirror can be moved by the voltage applied between the driving mirror and a transparent electrode which is located under the floating mirror. This structure contributes to the removal of the hysteresis mirror movement, realization of stable driving and higher display contrast. By experiments using fabricated IDDs, improvements of interferometric characteristics and hysteresis property are confirmed.

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The flavor of roasted sesame seeds was measured using a multichannel taste sensor. The lipid/polymer membranes built into the taste sensor output the electric potential difference between taste solution and inner solution. To apply the dry food such as sesame seeds to the taste sensor, it is necessary to extract taste substances into water. Taste solutions from sesame seeds were made by three methods; filtrate from dispersion solution, solution after centrifuging and removing insoluble substance, filtrate using degreased sesame seeds. The taste sensor showed the stable response to the centrifuged solution, and the flavors of sesame seeds with different roasting process and different producing district were discriminated with highly sensitivity.

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In recent years, instruments on the basis of multi-sensors combined with multivariate analysis have moved from R&D level to the production floor. Commonly known as “Electronic Noses”, these devices are now being used in the food and the pharmaceutical industry, cosmetics etc. for quality control. However they are insufficient to cover the areas for Environment, Safety and Health (ESH) like Sick-building syndrome and Soil pollution that cause crucial problems for human beings because of poor quantitatively. A portable mass spectrometer with membrane inlet has been developed and investigated its suitability as an electronic nose. This paper also discusses the potentiality to apply it for ESH industry with showing some preliminary results.

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