• 센서학회지
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• 제31권5호
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• pp.337-342
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• 2022

Hydrogen (H₂) gas is widely preferred for use as a renewable energy source owing to its characteristics such as environmental friendliness and a high energy density. However, H₂ can easily reverse or explode due to minor external factors. Therefore, H₂ gas monitoring is crucial, especially when the H₂ concentration is close to the lower explosive limit. In this study, metal oxide materials and their p-n heterojunctions were synthesized by a hydrothermal-assisted dip-coating method. The synthesized thin films were used as sensing materials for H₂ gas. When the H₂ concentration was varied, all metal oxide materials exhibited different gas sensitivities. The performance of the metal oxide gas sensor was analyzed to identify parameters that could improve the performance, such as the choice of the metal oxide material, effect of the p-n heterojunctions, and operating temperature conditions of the gas sensor. The experimental results demonstrated that a CuO/ZnO gas sensor with a p-n heterojunction exhibited a high sensitivity and fast response time (134.9% and 8 s, respectively) to 5% H₂ gas at an operating temperature of 300℃.

• 한국균학회지
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• 제23권4호통권75호
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• pp.354-358
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• 1995

용존 유기물의 농도를 BOD로 신속히 측정하여 폐수처리 공정에 feed back할 수 있는 Yeast BOD sensor 를 제작하여 BOD 측정의 거동을 조사하였다. BOD sensor의 감응도는 yeast의 활성이 가장 높은 pH 7.0 및 온도 $30^{\circ}C$에서 가장 높게 나타났다. Sensor에 충전되는 효모의 양도 감응도에 영향을 미치며 투석막 단위면적당 $ 0.14\;mg/cm^2$가 최적의 균체량이었다. 오염물질의 종류에 따라 BOD sensor의 출력 신호가 다르게 나타났으며 각각의 오염물질 속에 효모균를 전처리 시킨 후 sensor에 충전할 경우 sensor 의 감응도가 크게 증가하였다.

• 센서학회지
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• 제33권2호
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• pp.63-69
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• 2024

A novel method for measuring hydrogen concentration is introduced, along with its working principle and a novel detection algorithm. This configuration requires no additional reference compartment for potentiometric electrochemical measurements; therefore, it is the most suitable for measuring dissolved hydrogen in the liquid phase. The sensor's electromotive force saturates at a certain point, depending on the hydrogen concentration during the heating process of the sensor operation. This dynamic temperature scanning method provides higher sensitivity than the constant temperature measurement method.

• Journal of the Optical Society of Korea
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• 제2권1호
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• pp.34-37
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• 1998

We present a novel method for the stabilization of the Sagnac current sensor with active twist control. The sensor output was improved more than 8 times by employing the proposed stabilization method. Stability within $\pm$1.7% was demonstrated between 36$^{\circ}C$ and 62$^{\circ}C$.

• 센서학회지
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• 제1권1호
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• pp.85-92
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• 1992

4'-Aminobenzo-15-crown-5를 수식한 새로운 $K^{+}-ISFET$를 제조하고 그 감응특성을 조사하였다. $K^{+}-ISFET$의 pH에 대한 감응기울기는 30.0 mV/decade였으며, 감응시간은 3분 이상이었다. 또 $K^{+}-ISFET$의 $K^{+}$에 대한 감응기울기와 감응시간은 각각 $19.5{\pm}0.2{\;}mV/decade$와 약 3분이었다. $K^{+}$에 대한 이 센서의 직선감응범위는 $2.0{\times}10^{-4}{\sim}1.0{\times}10^{-2}M$이었다. 알칼리금속과 알칼리토금속 이온들에 대한 $K^{+}-ISFET$의 선택계수도 구하였다. 나트륨, 암모늄 및 칼슘이온 등이 비교적 크게 방해하였다. 이 센서의 장기안정도는 매우 개선되었으며, 약 50일 이상동안 사용할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.805-808
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• 2002

A carbon monoxide gas sensor utilizing Pt-SiC, Pt-SnO2-SiC diode structure was fabricated. Since the operating temperature for silicon devices in limited to 200oC, sensor which employ the silicon substrate can not at high temperature. In this study, CO gas sensor operating at high temperature which utilize SiC semiconductor as a substrate was developed. Since the SiC is the semiconductor with wide band gap. the sensor at above $700^{\circ}C$. Carbon monoxide-sensing behavior of Pt-SiC, Pt-SnO2-SiC diode is systematically compared and analyzed as a function of carbon monoxide concentration and temperature by I-V and ${\Delta}$I-t method under steady-state and transient conditions.

• 센서학회지
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• 제28권6호
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• pp.395-401
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• 2019

This paper proposes a method for estimating the location of a magnetized tip that is inside a non-transparent space or body by using arrayed giant magnetoresistance (GMR) sensors. In general, an object located in such an opaque space can be detected using X-rays, magnetic fields, ultra-sonic sensors, etc., depending on its characteristics. X-ray is mostly used for medical purposes but frequent exposure to it could cause harm to patients as well as doctors. In this study, how well a GMR sensor is applicable instead of an X-ray is investigated. The sensor's voltage output is experimentally fitted to distance with a relationship of 3rd degree polynomial. To detect a small magnetized tip with 900 Oe inside a human body, a 2×2 arrayed GMR sensor and a location estimation algorithm based on information acquired from four sensors is developed. Evaluation tests show that the suggested method is applicable to limited cases with a distance less than 33-55 mm, and the location of a magnet tip is estimated relatively well with an error less than 1.5 mm.

• 센서학회지
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• 제22권4호
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• pp.302-307
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• 2013

The Sb-doped $SnO_2$ nanowire network sensors were prepared by thermal evaporation of the mixtures between tin and antimony powders. Pure $SnO_2$ nanowire networks showed high sensor resistance in air ($99M{\Omega}$), similar gas responses to 4 diffferent gases (5 ppm $C_2H_5OH$, CO, $H_2$, and trimethylamine), and very sluggish recovery speed (90% recovery time > 800 s). In contrast, 2 wt% Sb-doped $SnO_2$ showed the selective detection toward $C_2H_5OH$ and trimethylamine, relatively low resistance ($176k{\Omega}$) for facile measurement, and ultrafast recovery speed (90% recovery times: 6 - 18 s). The change of gas sensing charactersitics by Sb doping was discussed in relation to gas sensing mechanism.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.63-63
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• 2008

Environmental monitoring sub-system has been developed using gas sensor module, Bluetooth module and PDA phone. The gas sensor module consists of $NO_2or$ CO gas sensor and signal processing chips. Gas sensor is composed of the micro-heater, sensing electrode and sensing material. Metal oxide nano-material was selectively deposited on a substrate with micro-heater and was integrated to the gas sensor module. The change in resistance of the metal oxide nano-material due to exposure of oxidizing or deoxidizing gases is utilized as the principle of this gas sensor operation mechanism. This variation detected in the gas sensor module was transferred to the PDA phone by way of Bluetooth module.

• 대한화학회지
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• 제35권1호
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• pp.38-45
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• 1991

Proteus mirabilis균과 organelle를 NH$_3$ 기체감응전극에 고정시켜 cytidine에 대한 바이오센서를 제조하였다. 박테리아 센서에 대한 pH, 온도, 완충용액, 균량 및 방해물질의 영향과 수명을 조사하였다. 그 결과 0.1M phosphate 완충용액에서 pH 7.8, 온도 30$^{\circ}C$, 균량 3mg이었을 때, 5.0 ${times}$ 10$^{-4}$M ∼ 1.0 ${times}$ 10$^{-2}$M cytidine 직선범위 내에서 56 mV/decade 의 감응기울기를 나타내었다. 이 박테리아 전극의 감응특성을 organelle 전극의 경우와 비교하였다.