The method using chirped ultrasonic wave to detect objects being near the boundary surface is presented. The flaws being near the surfaces of steel billets or the parts placed on a table are the examples of such object. In this method the discrimination of the objects and the measurement of the distances between the boundary surface to the objects can be performed, and the period of the modulated waves appearing on the envelope of the received signal corresponds to depth of the flaw and the modulation factor corresponds to the size of the object. The relation between the distance from the boundary to the object and the range of the sweep frequencies are discussed, thereby the guide line for the pulse width and the frequency deviation is derived. We carried out the two experiments in order to prove that this method is more useful than the current pulse echo method for detection of the objects being near the boundary surfaces. The one experiment is for the detection of the flaws in the billets, and the other is for the shape classification of the objects on the table.
The method proposed by this paper has the following practical advantages: (1) higher signal to noise ratio, (2) without the accurate time measurement, (3) without the precise data for the distance between the transducer and the boundary, (4) without the complicated signal processing.

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Solid-state electrochemical devices using proton-conductive antimonic-acid were examined for detecting small amounts of NO in wet air at room temperature. Two types of sensor devices were fabricated by using a disc or a thick film of antimonic acid. As a sensor signal, the electric current through the proton conductor was measured under the condition in which the constant voltage was applied between the sensing and the reference electrodes by means of a potentiostat. The current response of the sensor was found to be almost linear to NO concentration in the range of 0-100ppm. In addition, by selecting the applied voltage, it was possible to differentiate NO and NO₂ selectively. A small planar-type device using the thick film was also found to give fairly good sensing properties to NO. The NO_x sensing mechanism of the present sensor was briefly discussed.

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The mechanical behavior of deeply boron-doped silicon membranes is analyzed by using a simple analytical model. The boron-doped silicon membranes have intrinsic properties different from those of widely-used bulk silicon membranes: strong influence of a residual tensile stress and a thickness of less than 10μm. These characteristics enhance the nonlinear mechanical behaviors of the membranes as well as greatly decrease their sensitivity. This paper confirms the strong influence of these intrinsic properties on pressure-to-deflection response for boron-doped silicon flat and semi-bossed structures. By comparing the calculated values with measured values, an intuitive image for actual thin membranes is successfully obtained. Moreover, the temperature dependence of the capacitive sensors is discussed to propose a new model that considers the change in the residual stress and the elastic constant with temperature. The obtained results will be helpful in optimizing design parameters for capacitive pressure sensors.

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In this paper, we propose a new methodology on noncontact transportation of DNA molecules by dielectrophoretic force together with the Micro DNA Flow System. We utilize the conformational transition in the higher oder structure of DNA for transportation. Such systems can be constructed by using Microfabrication technology. At first, we designed a simple micro electrode-flow system and carried out experiments. Experimental demonstration of DNA transportation in the globule state using dielectrophoretic force and direct observation of the DNA molecule in a non-uniform electric field were carried out with fluorescence microscopy. Motion of the DNA molecule is modelled in terms of the spatial gradient in the electric field depending on the electrode design. We discuss the experimental result on the motion of the DNA molecule compared with theoretical prediction. We show that transportation of DNA with the state of compacted globule is profitable in the future practical application for the separation of giant DNAs such as human gene.

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We have experimentally measured the response time of an electrostatic S-shaped film actuator relative to environmental gas pressure and applied voltage aiming at an application to gas valve systems. This actuator has an Sshaped film element whose S-shape propagates in the lateral direction. We measured the propagation speed of the Sbend continuously from start to stop positions by detecting capacitance change between the film and one of the actuator electrode plates. It reached 7m/s when the pressure was 1Pa and the applied voltage was 120V. The response times of the actuator, in which the film travels 5mm laterally and 2mm vertically, are 7.7ms at atmospheric pressure and 2.2ms at a low pressure of 100Pa.

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