IEEJ Transactions on Sensors and Micromachines
Online ISSN : 1347-5525
Print ISSN : 1341-8939
ISSN-L : 1341-8939
Volume 118, Issue 12
Displaying 1-19 of 19 articles from this issue
  • Teruaki Katsube
    1998 Volume 118 Issue 12 Pages 547
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
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  • Yuji Miyahara
    1998 Volume 118 Issue 12 Pages 548-551
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
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  • Eiichi Tamiya
    1998 Volume 118 Issue 12 Pages 552-555
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
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  • Yasufumi Hino, Kiyoshi Toko, Kazuaki Daikokuya
    1998 Volume 118 Issue 12 Pages 556-560
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    Impedance changes in phospholipid LB (Langmuir-Blodgett) and protein-mixed phospholipid LB films by several taste substances were measured. The resistance of the phospholipid LB film increased by bitter and sweet substances, whereas the resistance decreased for salty, sour and umami substances. For sweetness the larger change was observed in the protein-mixed phospholipid LB film, and hence discrimination between sweetness and bitterness was possible.
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  • Il Yong Choe, Takumi Okada, Yoichi Sato, Yoshio Yasumori
    1998 Volume 118 Issue 12 Pages 561-565
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    A planar humidity sensor using anodic oxidized aluminium film (Porous alumina) has been developed. The basic structure of sensor is similar to n-MOSFET except that the gate region is formed by porous alumina as a humidity sensing element. Anodic oxidation is carried out in dilute H3PO4 solution at constant voltage of 10V. The sensors show a large current response for exposure to a high humidity (>50% RH) at room temperature. The time response of sensor during transient exposure to humidity is a few minutes. The mechanism of the current response to humidity is qualitatively discussed.
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  • Masayuki Morisawa, Gargi Vishnoi, Shinzo Muto
    1998 Volume 118 Issue 12 Pages 566-571
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    A new method for detecting dissolved oxygen in water is proposed here. The sensor is based on the enhancement of fluorescence yield by an interaction between tetoraphenylporphine (TPP) dye and oxygen molecules. In the presence of oxygen, when pumped by a He-Cd laser line of λ=441nm, it produced a strong fluorescence at around λ=656nm. The fiber-type sensor head was fabricated by cladding the fiber core (ARTON; nd=1.51) with the poly-4-methyl-l-pentene polymer (PMP; nd=1.47) doped with TPP. The experimental results indicated a good enhancement in the fluorescence for both oxygen gas and water dissolved oxygen (DO). The response was found to be linear and stable in the range of 100ppm- 1% for oxygen gas and lmg/l- 8mg/l for DO. The theoretical analysis and the sensor response for change in termperature are also discussed.
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  • Takashi Oyabu, Takeshi Onodera, Shigeki Hirobayashi, Haruhiko Kimura
    1998 Volume 118 Issue 12 Pages 572-577
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    Output patterns of four types of tin oxide gas sensors for compound gaseous indoor air-pollutants are investigated. The sensor patterns prefer higher gas-sensitivity characteristics when there is a compound gaseous pollutant including two kinds of gases. After the experimental system detects a lower gas-sensitivity pattern in a residence, it can detect a higher one. The reverse is impossible. Three NDVs (NDVA, NDVC, NDVN) characteristics are also adopted to increase the reliability of the system. NDVA characterisitic decreases for a few minutes and gets back to an original state or under the state when an alcoholic gas generates. The system can identify whether the alcoholic gas is generating or not in an indoor environment by using NDV characteristics with high reliability.
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  • Go Sakai, Teruyuki Jinkawa, Norio Miura, Noboru Yamazoe
    1998 Volume 118 Issue 12 Pages 578-583
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    A search for semiconducting oxides was carried out to design a sensor selective to NO over NO2. Bi203 was very selective to NO though not very sensitive among the various oxides examined, and NiO was proved to be the most effective promoter to Bi203 for enhancing NO sensitivity. The sensor element using 5wt%NiO-Bi2O3 showed fairly good sensing properties to NO in the range of 0-400ppm in sensitivity, selectivity over NO2 and response rate, at 300°C. The cross-sensitivities to C3H6, C3H8, H2 and O2 were modest or insignificant, compared to the sensitivity to NO. Catalytic activity tests and TPD measurements indicated that the response to NO (increase in resistance) was associated with its reaction with the surface oxygen of the element, while that to NO2 (decrease in resistance) resulted from its anionic adsorption.
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  • Motoi Nakao, Satoshi Nomura, Shuji Takamatsu, Katsuhiko Tomita, Tatsuo ...
    1998 Volume 118 Issue 12 Pages 584-589
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    The authors have developed a novel chemical imaging sensor, which enables us to observe two-dimensional pH-distribution in an electrolyte solution. A sample solution is in contact with the insulator (Si3N4/SiO2) on the Si substrate, which forms the electrolyteinsulator-semiconductor (EIS) structure. When modulated laser beam illuminates the backside of the Si substrate, ac photocurrent flows through the EIS structure. Since the photocurrent depends on pH value on the illuminated region, the two-dimensional pH distribution can be microscopically obtained by scanning the focused laser beam. The thickness of the Si substrate as well as the spot diameter of the laser beam restricts the spatial resolution of this sensor, This can be theoretically explained by the carrier diffusion model. The bonded Si on insulator (bonded SOI) wafer is employed for the thinner Si substrate. The chemical anisotropic etching is used in order to remove the Si bulk of SOI wafer. Using the sensor with the active Si thickness of 20μm, the spatial resolution as good as 5μm was attained. It is also estimated that the pH resolution is good as 0.01 in pH.
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  • Kazutoshi Noda, Ryuichi Naganawa, Hiroaki Tao, Mamoru Tominaga, Akira ...
    1998 Volume 118 Issue 12 Pages 590-594
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    A sensitive chloroorganics sensor using lipid coated quartz crystal microbalance (QCM) was developed. The mass change caused by a selective adsorption of chloroorganics on the surface of thin lipid film was detected as a frequency change of the QCM. Among the several lipids tested, the DC-7-12 gave the highs sensitivity for Trichroloethylene (TCE). A QCM coated with 5000ng of DC-7-12 gave the frequency change of 53Hz per 1000ppm of TCE, the calibration curve was linear up to 1000ppm. The response time was less than 2min. The sensitivity gradually decreased but it still showed more than 90% sensitivity after a months. By increase the amount of the coated lipid and by increase the basic frequency of the QCM, the sensitivity was improved up to 179Hz per 1000ppm. A possibility of selective determination of three different chlorrorganies was also shown by using the thin QCM coated with different kind of lipids
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  • Kotaro Nemoto, Supratic Chakraborty, Kazuhiro Hara
    1998 Volume 118 Issue 12 Pages 595-601
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    We have developed a multifunctional humidity-gas sensor on a silicon substrate by using thin-film technology and IC fabrication process. The size of the sensing film is 400μm×400μm, which is defined by photolithography. The sensing film is composed of Fe2O3(91mol%), TiO2(5mol%) and MgO(4mol%). It is deposited by rf sputtering on a porous Al203 film, which is made from Al by anodic oxidation. A Ta film is used as the bottom electrode while a Pt film is used as the top electrode. A part of the Ta film is oxidized into Ta2O5 just below the porous Al2O3 film. The impedance between the two electrodes is measured as a function of relative humidity or gas concentration.
    This sensor is sensitive to humidity when it is kept at room temperature. It is also sensitive to hydrogen gas when it is heated to 400°C. The porous structure increases the adsorption of water and gas molecules. The sensor is entirely made of stable materials with high melting points. So its sensitivity is recovered to its initial value by heat cleaning. The response times of the sensor to humidity change and concentration change of hydrogen gas are short.
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  • Hidehisa Murayama, Tsuyoshi Ogura, Kazuhiro Hara
    1998 Volume 118 Issue 12 Pages 602-607
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    We have developed an integrated thin-film gas sensor using semiconducting thin-films on an SiO2 diaphragm, which is formed on an Si substrate. A micro heater is fabricated on the same diaphragm. The fabrication procedure is based on thin-film and micromachining technologies and IC fabrication process. The two sensing films are composed of multi-layered metal oxides; an SnO2-based film on an Fe203-based film and a WO3-based film on an Fe203-based film.
    Both of the films are sensitive to reducing gases such as hydrogen (H2), isobutane (i-C4H10), and carbon monoxide(CO) as well as NOx gases when they are heated to 400°C by feeding an electric power of 540mW to the heater.
    The advantageous features of the sensor are as follows. It is a small and light-weighted device. It does not consume much materials and energy in the fabrication process. It does not contain any hazardous or poisonous materials that contaminate the environment. It can be mass-produced. It would be promising as a smart sensor in conjunction with electronic circuits on the same substrate.
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  • Wenyi Zhang, Takeshi Abiko, Shunichiro Watanabe, Elder Alpes de Vascon ...
    1998 Volume 118 Issue 12 Pages 608-613
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    Improvement of the stabilization and repeatability of the sensor response was investigated for the development of a tea taste sensor. For a semiconductor taste sensor (SPV sensor) with lipid membrane as the sensitive film, various washing methods were studied for the electrode cleaning after the tea taste measurement since hydrophobic molecules remain on the surface even after water rince. As the results, it was shown that effective refreshing method is possibly found by the selection of washing chemicals although the cleaning effect is different for the different lipid membranes. It was next shown that the commercial ion sensor was successfully applied as a tea taste sensor. The response was highly stable for the repeated measurements of the tea taste.
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  • Wenyi Zhang, Elder Alpes de Vasconcelos, Hidekazu Uchida, Teruaki Kats ...
    1998 Volume 118 Issue 12 Pages 614-620
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    We investigated thin catalytic metal gate Schottky diodes and pn heterojunctions for NOx detection. Thin Pt-Pd/Si/Al Schottky diodes were employed successfully to detect NO2 concentrations from 6ppm to 30ppm and NO concentrations from 50 to 250ppm, with a response roughly proportional to the logarithm of gas concentration. We investigated the fabrication of the diodes on a porous Si surface and the formation of a Si/WO3 heterojunction as possible ways to improve sensitivity. Diodes fabricated on porous Si showed slightly higher sensitivity to NO2. The sensitivity of a Pt-Pd/WO3/Si/Al heterojunction was comparable to the sensitivity of the Schottky diodes. The differences between the sensing mechanisms of these structures were also investigated and the results suggest that they provide different possibilities to enhance the sensitivity. An advantage of these sensors is to operate at room temperature. Moreover, the semiconductor junction structure is convenient to make smaller and intelligent sensors. Therefore, these structures may be considered for future development of NOx gas sensors at room temperature with miniaturization, integration and power saving features.
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  • Masaki YAMAGUCHI, Yoshio KANO, Masayuki MITSUMORI
    1998 Volume 118 Issue 12 Pages 621-626
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    If blood glucose levels measuring procedure is developed that can monitor blood glucose levels noninvasively, it will ease medical check drastically detection and cure of the disease at an early stage. This study aim to develop a noninvasively measuring of blood glucose using saliva. We manufactured a saliva analyzing system using glucose sensor and performed in vivo evaluations of it. As the results, it was cleared that determination of saliva glucose levels were in the range of 0.1 to 10.0mg/dl. This system allows us to monitor the time-course changes of saliva glucose levels. Thus, this measurement system of saliva glucose levels can be used as an indicator of blood glucose levels.
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  • Akira Kunimoto, Naoto Abe, Hidekzu Uchida, Teruaki Katsube
    1998 Volume 118 Issue 12 Pages 627-633
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    The novel semiconductor NOx gas sensor based on a heterojunction structure workable at room temperature has been investigated. The sensor consists of Pt/Tin-dioxide (SnO2)/n-Si/p+Si/Al in which vertical direction current between Pt and Al electrode was measured with applying reverse direction bias voltage on Pt electrode. All the films including SnO2 with the thickness of 50_??_200nm were deposited on an epitaxial layer of n-Si over p+-Si substrate by RF sputtering method. As a result, the current in the sensor decreased when the gas flow was switched from dry air to mixed gas of air and NOx. Clear response was obtained at the NOx gas concentration as low as 1ppm at room temperature, while the almost no response was observed for the n-Si and p-Si substrate. The generation of large change in current for the sensor with heterojunction structure was considered that barrier height change or conductivity change of SnO2 gas sensitive layer may cause the modulation of the depletion layer at the n/p+-junction of Si substrate.
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  • Akira Taniguchi, Yoshinobu Naito, Norihito Maeda, Hidekazu Ikezaki, Ki ...
    1998 Volume 118 Issue 12 Pages 634-640
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    Detection of some toxic substances in water is a time consuming process because large number of substances need to be analyzed. When some toxic substances in the drains flow into the river, they cause environmental destruction. Accurate detection of substances which have serious effects on living organism is required as well as short measurement time. Although a sensing system employing living fish is devised, there are some problems in reliability, maintenance and evaluation because they are living thing. It is possible to measure the influence of pollutant for living organism directly by a sensor which is similar to biological systems. So we investigate a method of detection of toxic substances by multichannel lipid membrane sensors which are modeled on living organism.
    SA401 has multichannel sensor with lipid membranes which are modeled on living organism. It is able to detect some toxic substances in the water. For the reason, this system has been applied to measure water quality, such as, mineral water, tap water, contaminated river water and factory drains. We have found this method is effective and many pollutants (e. g. CN-, Fe3+, Cu2+, etc.), in factory drains, have been measured in a few minutes, the detection limits are lower than regulations of drain. It is possible to detect cyanide of factory drains selectively in short time by applying lipid membrane sensor. In conclusion, it is an effective mean to use multichannel lipid membrane sensors for observation of water quality especially for factory drains.
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  • Jae-joon Choi, Kazuyuki Minam, Masayoshi Esashi
    1998 Volume 118 Issue 12 Pages 641-646
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    A bulk-micromachined silicon angular rate sensor has been developed. Electromagnetic excitation is adopted for driving its resonator with a large amplitude vibration (70μm). The induced vibration by the Coriolis' force is detected by electromotive voltage. The sensor is composed of a silicon-glass-magnet structure and only three masks are needed for this process. The sensitivity of this sensor was 233μV/(deg./sec) and highly sensitive and low cost silicon angular rate is achieved.
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  • Yuji Shiba, Takahito Ono, Kazuyuki Minami, Masayoshi Esashi
    1998 Volume 118 Issue 12 Pages 647-651
    Published: December 01, 1998
    Released on J-STAGE: December 19, 2008
    JOURNAL FREE ACCESS
    A capacitive AFM probe having capacitive structure was fabricated by micromachining techniques. For obtaining a high sensitivity and a low voltage-actuation, the thin micro sensor consists of a single crystalline-silicon with a narrow gap between micro-cantilever and opposite electrode was fabricated. The gap is lμm, the thickness of the cantilever is 0.5μm, and the size is 80×100μm. As a result of evaluation of the performance, the micro-probe showed a sufficient performance for nanometric sensing. The capacitive AFM probe has a both functions for sensing and actuation, because the deflection of the micro-cantilever can be measured from the capacitance, and the micro-cantilever can be electrostatically actuated. By reducing the cantilever size, the operation with a high speed imaging is expected.
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