[in Japanese]

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Simultaneous counting and drift compensation method is proposed for a simple correction of Quartz crystal (QC) smell sensor that is expected to use in a portable smell measurement device. In general, the frequency of the QC sensor is fluctuated by gate time, noise, temperature and humidity. The frequency fluctuation caused by the supply variation and noise was corrected by time-base QC sensor. The drift caused by temperature and humidity was tried to compensate by reference QC sensor. The frequency measurement resolution was proved by equalizing the slightly fluctuated counting time. The frequency drift was decreased by frequency differential approach between NH₃ QC sensor and reference QC sensor into less than 20%RH for the temperature and humidity variation. NH₃ density of 100 ppb could be measured by the smell measurement system.

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We propose an RFID signal transmission scheme that uses flooring tiles as a transmission medium. The method enables delivering RFID signals through a chain of flooring tiles patched together without electrical contact, thus easily extendable into a large scale. Potential applications include human flow monitoring in a large indoor situation by reading signals from numbers of distributed detectors labeled by RFID. In this paper, as a first step toward that goal, we focus on discussing the implementation of flooring tiles that can transmit signals at 13.56 MHz without electrical contact. To establish such transmission, we use a technique known as left-handed transmission, which is characterized by distributed series capacitance and shunt inductance. Here we present theoretical and numerical analysis to design such a system. Direct electromagnetic wave simulation of a realistic model reveals low-loss transmission of 0.23 dB/m at around 13 MHz.

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Odor sensing system with high sensitivity and selectivity is expected to be realized by using biological mechanisms such as olfactory receptor. We have already developed a cell-based odor sensing system which acquires odorant concentration as a fluorescent intensity change. In the measurement, however, an artifact is likely to happen due to lack of stable and reproducible methods for delivering odorants to biological cells. Therefore, we developed and evaluated the automated flow measurement system which can simultaneously control pump, solenoid valve, and camera. Our system realized automation of solution supply and fluorescent measurement. As a result, our system could reduce artifacts and repeatedly performed measurements with the same sensor cells.

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Here we report a portable wind/olfactory display system that can present a virtual airflow and/or odor source at an arbitrary position on a screen of a tablet computer. The system is named a smelling screen mini. As in our original-size smelling screen, airflows generated by four fans are made to impinge on each other, and thus, an airflow directed toward the user from a specified position on the screen is generated. By introducing odor vapor into the airflows, the odor distribution is as if odor vapor had been released from a certain position on the screen. However, it has been found that the airflows generated by the fans in the smelling screen mini are not properly impinging on each other and that the airflow directed toward the user is obliquely distorted. We have shown that the distortion is caused by the irregularities of the airflows from the fans. Experimental results are presented to show that the distortion of the airflow distribution can be effectively reduced by adding airflow straightening vanes and tapered flow paths to suppress the swirling motion of the airflows. The smelling screen mini can be used to add special effects to mobile games and electronic picture books.

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A function that expresses the relationship between data obtained from a sensory evaluation and those obtained from a taste sensor was approximated using a polynomial. First, the basis functions of a polynomial were set to a Legendre function, and the number of basis functions and their degrees were selected using a genetic algorithm. Next, the coefficients of the polynomial were calculated using multiple regression analysis. The approximation error was estimated using cross-validation, and the number of basis functions and their degrees were optimized so as to maximize the generalization of the polynomial. As a result, sufficiently small approximation errors were obtained for test data, and the explicit relationship between the data obtained from a sensory evaluation and those obtained from a taste sensor were clarified using the polynomial. The discrimination rate for food was improved using the estimated data of a sensory evaluation compared to a method that used only the data obtained from a taste sensor.

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This paper reports on fabrication and characterization of sharp Si nano dual AFM (atomic force microscope) tip. The narrow-gapped dual AFM tip was formed by self-align etching technique based on Si trench reactive ion etching, trench refilling with spin on glass (SOG), SOG etching and polishing back, and Si crystalline anisotropic etching to form triangular pyramid with inclined Si (111) plane and two vertical planes. When corner angle of the Si trench pattern was changed from 90° to acute angles, needle end of the dual tip was geometrically sharpened. In addition, radius of curvature of the dual tip was sharpened by low-temperature thermal oxidation even though gap between the tips slightly widened about 290nm. Moreover, Si dual tip fabrication was demonstrated on a dual AFM cantilever with sputtered FePd film on Silicon on insulator (SOI) wafer.

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In this paper, the liquid concentration sensor using crystal oscillator circuit which is available for measuring microdroplet is reported. We optimized the design of the sensing capacitor (SC) for sensing microdroplet. An electric-field-concentrated SC was used for measuring the liquid. The SC incorporated into the quartz oscillator has high-sensitivity because of the high stable crystal oscillator circuit. The SC is embedded in a silicone rubber. A spatially confined electric field is generated over the rubber. Therefore, the frequency of the oscillator changes by the contact with a liquid to the rubber. Moreover, the change less affected by a quantity of liquid. Because the frequency changes relate to the electrical characteristics of the liquid, the concentration of the liquid can be measured by the sensor. This sensor is expected to be applied to factory automation.

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