The three axis SOI capacitive accelerometer has been developed using silicon bulk micro- machining. The accelerometer has a glass-silicoll structure measuring 2.8mm by 2.8mm by 1.0mm. The accelerometer has a 500μm thick silicon mass formed by dicing using a SOI substrate. The accelerometer structure was released by R.I.E. process so that the sensor did not break or stick to the substrate. This process promises high throughput and high yield. The accelerometer was assembled with a switched-capasitor circuit and the characteristics were evaluated. The typical characteristics are as follows; Acceleration range is ±1.2G, sensitivity is 0.6V/G, cross-axis sensitivity is less than 7%.

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This paper proposes a 3-D measurement principle for the correlation image sensor (CIS) which generates temporal correlation between incident light intensity and an external reference signal at each pixel. Another key of our system besides the CIS is amplitude modulation of the scanning sheet beam, the phase of which relative to a reference signal is varied according to the angle of the sheet beam. After a scan within a frame, the phase is demodulated with a quadrature pair of reference signals and output by the CIS to compute the individual angle of the sheet beam on each pixel. By virtue of the lock-in detection principle, effects of background illumination and/or surface reflectance nonuniformity of the object are thoroughly removed. We impleinented this system using our CMOS 64×64-pixel CIS, and successfully reconstructed a depth map under its frame rate (30Hz).

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High-quality charcoal Bincho is famous as charcoal to make purification of water namely enjoyable water. Recently, however, it is bamboo charcoal that attracts attention to healthy water. This paper describes that examining purification action of water of this bamboo charcoal and water analysis by using our multichannel measurement system with seven ion-selective electrodes. Furthermore, a quantity change of water by ICP (Inductively Coupled Plasma) analysis and X-ray analysis of inorganic metal matter was observed. As cross check, the analysis results have proven possibility for purification of water by bamboo charcoal.

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In order to improve detection sensitivity of UV absorption detection on a chip for capillary electrophoresis (CE), we have developped the microfabricated CE chips which have silicon shade at bonding interface. Although the CE chips are fabricated with a simple process, the Si shade is ideal structure as an optical slit. It was confirmed, using the CE chips, that the detection sensitivity of UV absorption detection was improves about ten times, and a DNA sample analysis with UV absorption detection was perfomed.

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A simple analytical method for the determination of volatile chloroorganic compounds, such as trichloroethylene (TCE) and tetrachloroethylene (PCE), in water using a lipid-coated quartz crystal microbalance (QCM) sensor was developed. By shaking a water sample in a sealed-bottle for 30sec, concentration equilibrium of volatile chloroorganic compounds was attained between water and headspace gas in the bottle. The frequency change of the QCM sensor, which was monitored after inserting it into the headspace of the sealed bottle, was turned out to be proportional to the concentration in water. Comparison of analytical performance of the QCM sensor and that of the gas detector tube, conventionally used for monitoring of these gases, was carried out. The former method gave a wider dynamic range of the measurement. As another means of vaporization of volatile chloroorganic compounds from the water samples, a purified air was passed into the water and circulated in a closed system for about 300sec. Then, the air containing vaporized chloroorganic compounds was transferred into a flow cell incorporating four types of QCM sensors and the frequency changes were monitored. The QCM sensor, which gave the highest sensitivity, was a 353AN coated-QCM sensor and its sensitivity was beyond 3.6Hz/ppm.

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Recently, sick-house syndrome receive much public attention as a problem of indoor environment. Volatile organic compounds (VOCs) such as formaldehyde HCHO) and xylene (C₆H₄(CH₃)₂) generated from building materials are pointed out as one of origins of sick-house syndrome. In the present work, in order to develop a semiconductor type VOC sensor, first of all, the sensitivities of several oxide semiconductor materials were studied. Among the 23 metals oxides examined, the highest sensitivity to HCHO was achieved by SnO₂. Further, the sensing property of an SnO₂ sensor to 100ppm HCHO was extremely improved by addition of 3 wt% Ag at 300°C, but the sensor had a short lifetime. In order to explore another additives, VOC sensing properties of SnO₂ loaded with several metal oxides were investigated. Among the elements loaded (5 wt%) with each of 14 metal oxides, the Mn₂O₃-loaded one was outstanding in sensitivity to HCHO at 200°C. However, its sensitivity of the doubly promoted sensor, Ag (1 wt%)-Mn₂O₃ (5 wt%)-SnO₂ to HCHO was lower than that of each sensor loaded with one additive.

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In the field of measurement, we often face the situations where pipe lengths have to be indirectly measured. As the indirect measurement media, light and sound waves are well known. But, in the cases where vapor appears and/or the pipes have curves and branches, light waves cannot be applied because of its scattering and rectilinear propagation properties. On the contrary, sound wave is not affected by the vapor, and also not strongly affected by curves and bend points in the propagation.
One of the authors thus previously developed a pipe length measurement system for straight pipes using the sound wave. The system modeled the stationary wave, instantaneously generated in the pipe, as an output of a linear dynamic system and enabled an on-line high-accurate pipe length measurement using a maximum likelihood method. This paper extends the method to be able to measure the lengths of pipes with curves and branches. Experimental results will show that accurate pipe length measurement is realized with the method.

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Schottky barrier diode has been fabricated on the diamond film and its gas sensing characteristics in nitrogen dioxide (NO₂) gas have been investigated. The Schottky structure was composed by using a p-type surface conductive layer, which was formed on the as-grown diamond film, with metal contacts.
The capacitance-applied voltage (C-V), capacitance change rate for NO₂ gas concentration and time response in NO₂ gas atmosphere and in dry air were measured. The capacitance change rate in NO₂ gas had a maximum between-1V and 0V of applied voltage. The reversible time response was obtained when the NO₂ gas injection was repeated. It was also indicated that the capacitance change rate was increased as the gas concentration increased. From these results, it was found that the diamond Schottky diode using the p-type surface conductive layer could be applied to the NO₂ gas sensor devices.

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