• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.22-34
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• 1998

The purpose of this study is to develop biosensor for determination of glucose, lactate, and ethanol in foods and food-stuffs simultaneously. The multiple cathode system was prepared with an oxygen electrode having one anode and hexagonal cathode. Glucose oxidase, mutarotase, lactate oxidase, alcohol oxidase and catalase were used for immobilization to determine glucose, lactate, and ethanol. These components including ethanol were simultaneously determined by the immobilized enzymes in the multiple cathode system. The determination of the components by enzyme sensor was based on the maximum slope of oxygen consumption from enzyme reaction of each sensor part. The response time for analysis was 1 min. The optimum condition for glucose, lactate and ethanol sensor was found to be 0.1 M potassium phosphate buffer, pH 7.0 at $40^{\circ}C$. Interferences of various sugars and organic acids were investigated. Less than 10% of error was found in determination of the components except organic acids. This difference was compensated by the modified equation. This system was confirmed by conventional methods. It was concluded that the multiple cathode system of this study is for an effective method to determine sugar, organic acid, ethanol simultaneously in foods.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.1
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• pp.88-94
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• 2012

Histamine is a kind of primary biogenic amine arising from the decarboxylation of the amino acid L-histidine. The toxicology of histamine and its occurrence and formation in foods are especially emphasized in fermented foods. In this study, the biosensor for detection of histamine with functionalized multi-walled carbon nanotubes (MWCNT) was developed. We also searched for an appropriate insoluble substrate to immobilize the enzyme. The developed biosensor showed a detection limit of $0.1{\mu}M$ hydrogen peroxide. The enzyme reactor was prepared with diamine oxidase immobilized on insoluble carriers including CNBr-activated sepharose 4B, calcium alginate, and controlled pore size glass beads. The coupling efficiency of CNBr-activated sepharose 4B, calcium alginate, and controlled pore size glass beads were 48.5%, 40.3%, and 51.0%, respectively. In addition, the response currents on histamine with each immobilized enzyme reactor prepared with CNBr-activated sepharose 4B, calcium alginate, and controlled pore size glass beads were 120 nA, 110 nA, and 140 nA at $100{\mu}M$ of histamine concentration, respectively. Therefore, it is suggested that controlled pore size glass beads are the best carriers for immobilizing diamine oxidase to detect histamine in this biosensor.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.1-5
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• 2008

As bare Fiber Bragg Grating (FBG) sensors are very fragile, bare FBG without encapsulation is not properly applied in practical infrastructures directly due to the harsh environment in practical engineering. Steel sleeve packaged FBG strain sensor is widely used in civil engineering. Since FBG senses both strain and temperature simultaneously, for accurate measurement of strain, temperature compensation for FBG strain sensors is indispensable. In this paper, based on the FBG's strain and temperature sensing principles, the temperature compensation techniques for steel sleeve packaged FBG sensors are brought forward. And the experiment of concrete early-age shrinkage monitoring by dual FBG sensors is carried out to test the feasibility of the temperature compensation technique.

• Journal of Drive and Control
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• v.21 no.1
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• pp.53-58
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• 2024

With the recent development of intelligence and automation technologies for construction machinery, the demand for safety and efficiency of road-cutting operations has continued to increase. In response to this, a double-blade road cutter has been developed that can automatically cut roads. However, a double-blade road cutter has a load difference between the two blades due to the ground and wear conditions of the cutting blades. The difference in load between the two blades distorts the direction of travel of the cutter. In this study, a vision sensor-based driving guide technology was developed to correct the driving path of road cutters. In addition, we developed a load-sensing technology that detects blade loads in real-time and controls driving speed in the event of overload.

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.221-227
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• 1997

The Pd/NiCr gate MISFET-type sensors were fabricated for detecting hydrogen dissolved in high-capacivity transformer oil. To improve stability and high concentration sensitivity of the sensor, Pd/NiCr double catalysis metal gate was used. To reduce the serious gate voltage drift of the sensor induced by hydrogen, the gate insulators of 2 FETs were constructed with double layer of silicon dioxide and silicon nitride. The hydrogen sensitivity of the Pd/NiCr gate MISFET is about a half of Pd/Pt gate MISFET's sensitivity but the Pd/NiCr gate MISFET has good stability and high concentration detectivity up to 1000 ppm.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.324-330
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• 2007

A new ion selective PVC membrane electrode is developed as a sensor for mercury(II) ions based on bis(benzoylacetone) propylenediimine (H2(BA)2PD) as an ionophore. The electrode shows good response characteristics and displays, a linear Emf vs. log[Hg2+] response over the concentration range of 1.0×10-6 to 1.0×10-1 M Hg(II) with a Nernstian slope of 29.8±0.75 mV per decade and with a detection limit of 2.2×10-7 M Hg(II) over the pH range of 2.5-11.5. Selectivity concentrations for Hg(II) relative to a number of potential interfering ions were also investigated. The sensor is highly selective for Hg(II) ions over a large number of cations with different charge. The sensor has been found to be chemically inert showing a fast response time of 60 s and was used over a period of 3 months with a good reproducibility (S = 0.27 mV). The electrode was successfully applied to determine mercury(II) in real samples with satisfactory results.

• Analytical Science and Technology
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• v.28 no.2
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• pp.98-105
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• 2015

The development of an enzymatic biosensor for dopamine determination based on multiwall carbon nanotubes (MWCNTs) and peroxidase obtained from the crude extract of burley tobacco (Nicotiana tabacum L.) was proposed. Peroxidase catalyzes the oxidation of dopamine to dopamine quinone. The influence on the response of analytical parameters of biosensors such as enzyme concentration, dopamine concentration, pH, and phosphate buffer solution concentration were investigated. The analytical parameters obtained, including sensitivity, linearity, and stability, were investigated. The proposed method for dopamine determination presented good selectivity even in the presence of uric acid and ascorbic acid. The sensor presented a higher response for dopamine in 0.010 M phosphate buffer at pH 6.50, with an applied potential of -0.15 V. The detection limit of the electrode was 2.7×10⁻⁶ M (S/N = 3) and the relative standard deviation of the measurements, which were repeated 10 times using 5.0×10⁻² M dopamine, was 1.3%.

• Journal of Sensor Science and Technology
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• v.5 no.1
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• pp.15-22
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• 1996

FET type $Ca^{2+}$ sensor(Ca-ISFET) was fabricated by micropool and photolithographic method utilizing photosensitive polymer as membrane materials. When OMR-83 negative photoresist was used as membrane material, it gave good sensitivity by micropool method with dioctyladipate as plasticizer but it could not be used in the photolithographic method. When poly(viny1 butyral), PVB was used as membrane material, it gave relatively high sensitivity ($23{\pm}0.2\;mV/decade$) for $Ca^{2+}$ concentration range of $10^{-4}{\sim}10^{-1}\;mole/{\ell}$ by photolithographic method. PVB also provided good adhesion to the pH-ISFET base device without adhesion promoter pretreatment and any plasticizer.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.30.2-30.2
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• 2009

TiO2는 3가지의 결정구조를 가지고 있으며 결정 입자, 구조, 상의 형태에 따라서 성질 및 기능에 영향을 주고 있다. anatase상의 애너지 밴드갭과 전자와의 재결합 확률이 크기 때문에 Rutile상 보다 우수한 성질을 갖고 있어 산화물 반도체로 이용하는 것이 적합하다. 본 실험에서는 나노로드의 TiO2를 수열처리법에 의해 합성한 후 박막을 제조하여 감응특성을 조사하였다. X선 회절분석기(X-Ray Diffraction)로 분석결과 ph=1의 루타일상을 제외하고, pH=2~7의 더 넓은 구간에서 뚜렷한 회절피크의 anatase 상이 나타났으며 다른 비정질상이 발생되지 않는 결정성이 좋은 단결정임이 나타났다. NaOH solution 을 이용하여 수열처리후 $180^{\circ}C$이상의 특정 온도 구간에서 수십 나노 로드 형태로의 2차 성장된 모습을 TEM과 EDS로 결정구조와 화학조성을 분석하였다. 그리고 BET 측정을 통해 $180^{\circ}C$의 소성온도에서 TiO2 입자의 비표면적이 가장 우수한 것으로 나타났다. 나노로드의 수용액을 Al2O3기판의 감지막 위에 떨어뜨려 네트워크된 막을 형성한후에 센서를 제작하였다. 히터 전압이 $400^{\circ}C$에서 나노 파우더센서에서는 반응이 일어나지 않은 반면, 나노 로드센서는 CH3SH에서 28% 의 높은 감도를 얻었고, Toluene의 반응에서는 15%의 감도가 나타났다. 그 외 NO, CO, H2등의 측정에서 아무런 반응이 일어나지 않았다. 이는 비교적 기공이 큰분자(Size)를 가진 CH3SH=76nm, Toluene=60nm에서 반응이 일어난 반면, H2=28nm, CO=22nm에서 감도가 나타나지 않은 것을 보아 흡착분자크기에 의한 영향이 큰 것으로 나타났다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.225-226
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• 2003

최근 인간의 생활환경에 존재하는 유해가스 및 대기 환경에 대한 관심이 고조되면서 환경유해가스를 손쉽게 감지할 수 있는 센서의 필요성이 중요하게 인식되고 있다. 그 중 암모니아 가스는 생활환경 내에 존재하는 악취성분일 뿐만 아니라 냉각기의 냉매로 사용되는 가스로서 대기 중 허용농도가 50 ppm으로 알려져 있다. 본 연구에서는 프린트스크린 인쇄법을 이용하여 SnO$_2$를 모물질로 하여 귀금속 산화물인 Pt와 Au를 첨가한 암모니아 반도체 가스센서를 제조하여 그 감도 및 SO$_2$, NOx, CH$_4$, NH$_3$, 에 대한 선택성을 분석하였다. (중략)