This paper describes three structures to passively remove condensed water droplets from a gas heat conduction type hydrogen sensor for fuel cell applications. The three structures are A: water-repellent coating surrounded by water-absorbing porous ceramic coating, B: suspended porous membrane over a water-repellent sensor surface and C: wettability gradient for water droplet elimination. A real hydrogen sensor was used as a platform for the water-droplet-removal structures. Using helium instead of hydrogen, A and B type sensors and a reference sensor without water-droplet-removal structures were tested in a wet and hot atmosphere simulating a fuel cell environment. B type sensor showed normal output even after exposure to a dew-condensing atmosphere, while the reference and A type sensors showed abnormal output, suggesting dew condensation on the sensor surfaces. For C type sensor, a photochromic compound film on a super-water-repellent undercoat, which changes its wettability by ultraviolet exposure, was used. It was confirmed that the wettability could be controlled by ultraviolet exposure from 157.9° to 72.8° in water contact angle.

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AlN thin film is widely utilized for piezoelectric devices e.g. acoustic filters and sensors, since AlN has well-balanced properties such as high acoustic velocity, low loss at high frequency, moderate electro-mechanical coupling coefficient and moderate temperature coefficient, and can be deposited at relatively low temperature. The sputtering technology using ECR plasma can deposit a highly-oriented AlN thin film by the assist of low energy plasma flow. However, its residual stress is normally highly-compressive, and thus free-standing AlN MEMS are easily broken during the fabrication process. In this research, to solve this problem, we investigated the reduction of AlN compressive stress, and the full width at half maximum of the XRD rocking curve (FWHM_XRD:RC) by changing various parameters such as substrate bias voltage, the gas flow ratio of Ar:N₂ and substrate temperature. It was experimentally confirmed that the positive substrate bias voltage and the substrate temperature can considerably reduce AlN compressive stress to nearly zero without remarkable deterioration of FWHM_XRD:RC.

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In this paper, I treat the electrically actuated structures in systems with one degree of freedom involving the second order displacement terms. The general and vibration solution of the approximate governing equation is described by the elliptic function.

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Water Detecting Sensor using solid state protonic conductor has been developed for Gas Insulated Swicthgear. Ttriethlenediaminesulfate was selected as protonic conductor with which elcterochemical sensor was constructed. The water detecting characteristics and its reliabilities were examined. The sensor detected water concentration from several ppm to about 2000ppm (at 5ata) as an output electric current, and was able to detect sufficiently water of 50ppm (at 5ata) which was the targeted value of the sensor. The mechanical strength increased by adding a polymer in the electrolyte. We also examined the influence to an output characteristic by the polymer addition and reliability. We proposed that without heating process was preferable in constructing sensor.

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In order to study the basic subjects needed to realize phased-array antennas especially for mobile system applications, we have developed core components for the antenna. Wilkinson power divider, a switched-line phase shifter, a single-element patch antenna and a 4-element patch array antenna were designed for 2.5 GHz operation. Low loss MEMS shunt switches were employed for the phase shifter. All the circuits were formed on a glass-epoxy base printed circuit board. The circuit patterns were designed based on the simulation by Sonnet, a 3D planar electromagnetic field solver software. Good performance was achieved in these components, e.g., the transmission coefficient (S₂₁) of -1.8 dB with 91.8 degrees phase shift for a phase shifter, the reflection coefficient (S₁₁) of -27 dB for a single-element antenna and the reflection coefficient (S₁₁) of -34 dB for a patch array antenna. Also, the design accuracy for the core components was confirmed throughout this work.

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An antigen-antibody sensor consisting of a silicon-based chip contains a mixture of poly [ethylene glycol] (PEG)-grafted carbon nanotubes (PEG-CNTs) and CNTs modified with an antigen by using plasma ion irradiation (plasma activation) method, is developed. According to result of experiments, impedance increased due to antigen/antibody reaction. The results indicate that this antigen-antibody sensor could react until 10 g/ml antigen density.

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We have developed and demonstrated a volume display prototype using organic electrochromic pixel elements. Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)-based pixels and wirings were patterned on flexible plastic substrates and bent to form voxels in a three-dimensional space. PEDOT:PSS pixel elements changed their color from transparent to blue under an applied potential of -1 V. The maximum light absorption of PEDOT:PSS at a wavelength of 630 nm was 0.6. 1-cm³ voxels were placed in a 3 × 2 × 3 array. Selected voxels were projected and observed not only from the front view but also from the side view.

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