A taste sensor is developed by imitating the mechanism in gustatory systems. Various foods have been measured using the taste sensor, and identification and quantification of taste have become possible. However, it is difficult to measure temperature characteristic of taste in human using the taste sensor, because the membrane potential is influenced by temperature change of the internal solution. The purpose of this study is to measure temperature characteristic of bitter taste using an improved measurement system and to compare the measurement results with a sensory test. As a result, the membrane potential is not influenced, when the temperature change of the internal solution is less than about 8°C. Moreover, the measurement results agreed with the results of sensory test.

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The gallium nitride (GaN) is used as the wide band gap material for next generation power semiconductors and high frequency devices. We have prepared the samples of the GaN epi-layer on the sapphire substrate with a different atom (Ga-face or N-face) that composed the outermost surface. The nanoscale investigations of the samples of topography and surface potential in the same region by an instrument that the frequency modulation atomic force microscope (FM-AFM) combined with the Kelvin probe force microscope (KFM) were performed. It is estimated that band bending of the samples from the surface potential image, and drawn to the energy band diagram. In comparison with the topographic images, it was confirmed that the N-face layer had occurred many crystal defects more than Ga-face one. Since the different potential state for a crystal defect were observed, and it was considered to correspond to the dislocation types.

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An ion sensor of all solids type using Ag/AgCl standard electrode was previously reported. It was thought impedance measurement of chloride ion concentration instead of potentiometric measurement will be possible. In this study, chloride ion response characteristic in various solutions and influence of temperature were evaluated using Nyquist plot analysis.

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In solid oxide fuel cell, carbon dioxide is generated in the water circulator and tends to accumulate in the reformer. If the air bubble forms a fair size, it disturbs the water flow and gives damage to the water circulator. For practical applications, long-term operation with an air bubble detection capability is needed. The purpose of this paper is to enhance the sensitivity of the air-bubble sensor by increasing the physical water repellency of its detecting surface using micro- and nano-periodic structures. The air-bubble sensor comprised a cylindrical sleeve with two coil shaped-electrodes and a ground electrode. Four types of sleeves for the air-bubble sensor with different micro- and nano-periodic structures on the surface of a detection area were fabricated. As the results, it was found that i) a micro-periodic structure increased the apparent contact angle of air bubble from 50° to 89°, and ii) a V-shaped micro-periodic structure could degrease the accidental error by improving the wettability. The electrode voltage was increased toward the detection threshold level and the detected time was prolonged when the apparent contact angle of water was small, showing that which increase the probability of false detection. Additionally, the detecting sensitivity of the air-bubble sensor was increased by forming a micro-periodic structure on the surface. In summary, a micro-periodic structure has the effects improving the detecting precision of air-bubble sensor.

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The stimuli-responsive polymer-based two dimensional photonic crystal (2D-PhC) for chemical sensor application was fabricated using nanoimprint lithography (NIL). The polymer-based 2D-PhC was fabricated using ultraviolet (UV)-curable Poly(dimethyl siloxane) (PDMS) as a base material. By using this polymer-based 2D-PhC, structural color based on Bragg's equation could be observed. In addition, polymer-based 2D-PhC was exposed in hexane vapor, the structural color change (blue to green) due to the swelling of PDMS could be observed in naked eyes. From this result, polymer-based 2D-PhC using PDMS was successfully applied as a cost-effective chemical sensor.

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Finger tracking using motion sensor has been attractive technique for non-contact operation of electric devices. Piezoelectric ultrasonic sensors can be applied to the motion sensing by the detection of the reflected waves from objects. The piezoelectric sensor, however, is impossible to detect the motion at close range because the several ultrasonic waves are overlapped. In this study, the array of electret condenser sensors with film lamination (FilmECS) was fabricated to track a finger above a mobile device. The receiving sensitivity, the transmitting power and the sensitivity of transmitting and receiving were measured to investigate the characteristics of the sensor array. The resonance peak of the fabricated FilmECS was estimated to 50-60 kHz and around 70 kHz for receiving and transmitting, respectively, Furthermore, the sharp reflected waveform from an artificial finger was obtained by the FilmECS at transmitting and receiving. Eventually, the location of the fingertip could be detected at the distance up to 3 cm between the array and the fingertip.

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This article consists of element structure with composition of ZMCT-25 and ZMCT-55 as two layers. ZMCT-25 is composition with a little content of TiO₂, the sensitivity is high, the bondability of the electrode is low. On the other, ZMCT-55 is composition with much content of TiO₂, the sensitivity is small, the bondability of the electrode is superior. Therefore, we found the possibility of the direct-heated gas sensor by an element with MCT-25 and MCT-55 as two layers structure. In addition, this clause describes sensor properties by the closed loop control using these two layers element and this element.

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