• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.11
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• pp.1315-1322
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• 1988

$SnO_X$/Pt thin film gas sensors were fabricated and their performance characteristics were measured. The $SnO_X$/Pt films were deposited by vacuum evaporating the $SnO_2$ target mixed with 2 wt% Pt. The conductivity showed the temperature dependence and the sensitivity to CO gas was proportional to the square root of gas concentration below 2000 ppm. The optimum operating temperature of the fabricated devices was about 300$^{\circ}$C and the response time in 5000 ppm CO gas was about 20 sec.

• Korean Journal of Materials Research
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• v.34 no.5
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• pp.235-241
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• 2024

Gas identification techniques using pattern recognition methods were developed from four micro-electronic gas sensors for noxious gas mixture analysis. The target gases for the air quality monitoring inside vehicles were two exhaust gases, carbon monoxide (CO) and nitrogen oxides (NO_x), and two odor gases, ammonia (NH₃) and formaldehyde (HCHO). Four MEMS gas sensors with sensing materials of Pd-SnO₂ for CO, In₂O₃ for NO_X, Ru-WO₃ for NH₃, and hybridized SnO₂-ZnO material for HCHO were fabricated. In six binary mixed gas systems with oxidizing and reducing gases, the gas sensing behaviors and the sensor responses of these methods were examined for the discrimination of gas species. The gas sensitivity data was extracted and their patterns were determined using principal component analysis (PCA) techniques. The PCA plot results showed good separation among the mixed gas systems, suggesting that the gas mixture tests for noxious gases and their mixtures could be well classified and discriminated changes.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2038-2039
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• 2007

In this work, a novel semi-internal type UHF PD sensor has been proposed and related investigations has been performed in order to detect the partial discharges that could be possibly produced at the insulation system of the gas insulated switchgear(GIS). This sensor was designed to mount on the CT terminal hole of GIS using the spiral antenna theory. Therefore this type sensor can be install on GIS during the power apparatus has been operation and better sensitivity compare to the commercial external type UHF PD sensor.

• Journal of the Korean Ceramic Society
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• v.36 no.3
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• pp.237-243
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• 1999

스크린 프린팅법을 이용하여 NOX 감지용 WO3 후막형 가스센서를 제조하였다. 본 실험에서는 감지막의 소성 온도에따른 감도변화 및 Ru을 첨가함으로써 감도의 증진을 중점적으로 조사하였다. 또한 NO2 50 ppm하에서 CO, H2, CH4 그리고 i-C4H10등의 가스에 대하여 cross sensitivity를 조사하였다. WO3 가스센서는 소성온도 50$0^{\circ}C$, 작동온도 30$0^{\circ}C$에서 최대감도를 얻었다. 순수한 WO3에 Ru(0.004 wt%)을 첨가시 NO2 및 NO 가스에 대한 감도가 크게 증진되었다. 그러나 순수한 WO3 센서는 Ru(0.004 wt%)이 첨가된 WO3 센서보다 더 우수한 cross sensitivity를 보였다.

• The KSFM Journal of Fluid Machinery
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• v.11 no.4
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• pp.52-62
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• 2008

All forecasts of a future energy demand anticipate an increase across the globe. With the increase of energy demand, the emission of $CO_2$ is also likely to increase by at least the same amount because energy supply will be based on fossil fuels, which is more apparent in a number of developing countries. In this context, the Micro Gas Turbine (MGT) is being considered as a promising solution. In order to propose a feasible concept of those technologies such as improving environmental effect and economics, we performed a sensitivity study for a biomass fueled MGT using a simulation model. The study consists of 1) the fundamental modeling using manufacturer's technical specifications, 2) the correction with the experimental data, and 3) the sensitivity study for system parameters. The simulation model was developed by PEPSE-GT 72, commercial steam/gas turbine simulation toolbox.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.515-523
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• 2015

In this paper, we fabricated and evaluated the gas sensor for the detection of CO gas and $NO_X$ gas among the vehicle exhaust emission gasses. The $SnO_2$ (tin dioxide) layer is used as the detection material, and the thin-film type and the nano-fiber type layers are deposited with various thicknesses using sputtering method and electro spinning method, respectively. The experiments are performed in the chamber where the gas concentration is controlled with mass flow controller. The fabricated devices are applied to the CO and $NO_X$ gas, where the device with the thinner $SnO_2$ layer shows better sensitivity. The nano-fiber has the larger surface area, and the shorter response time and recovery time are obtained. From the experimental results, both types of gas sensors successfully detect CO and $NO_X$ gases, which can be applied to measure those gases from the vehicle emissions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.347-349
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• 1997

In order to investigate CO sensing property of a SnO$_2$-WO$_3$composite ceramic. we prepared pure SnO$_2$and WO$_3$added SnO$_2$compostie ceramics. Using XRD and SEM, a phase analysis and microstructure were investigated. The resistances as a function of gas atmosphere were measured by High Voltage Measure/source Unit. The measured 1000ppm CO gas sensitivity of SnO$_2$-WO$_3$composite ceramics were smaller than that of pure SnO$_2$.

• Journal of Sensor Science and Technology
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• v.9 no.5
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• pp.357-364
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• 2000

The structural, electrical and gas sensing characteristics of $LaFeO_3$ thin films fabricated by r.f. magnetron sputtering method on $Al_2O_3$ substrates were investigated. (121) domonant crystalline plane was observed for the films heat-treated at above $600^{\circ}C$ and gas sensing properties showed p-type semiconductor behaviors. Gas sensing characteristics of the $LaFeO_3$ thin films was studied as a function of film thicknesses and heat treatment temperatures. While the variation of the film thickness showed a little effect on the sensitivity, the heat treatment temperature was critical to the sensitivity. The thin films with thickness of 400 nm heat-treated at $800^{\circ}C$ showed the sensitivity of 400% for 5000ppm CO and 60% for 350ppm $NH_3$ at the working temperature of $300^{\circ}C$.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.13-19
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• 2014

Dynamic ductile fracture (DDF) has been studied in the transportation pipeline for the carbon dioxide capture and storage(CCS) system. DDF behavior of CCS transportation pipeline has been analyzed using Battelle Two Curve Method (BTCM) and compared with the DDF behavior of natural gas pipeline. The operating safety criteria against the DDF has been investigated based on the sensitivity analyses of the pipe thickness and the operating temperature for the $CO_2$ pipeline. The DDF criteria can be applied to confirm the operating safety of the $CO_2$ pipeline. If the commercial natural gas pipeline were used at room temperature as a $CO_2$ pipeline, the thickness of pipe should be at least 7mm and the pressure should be less than 54bar for the $CO_2$ pipeline system.

• Journal of Sensor Science and Technology
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• v.17 no.3
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• pp.178-182
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• 2008

Planar type micro catalytic combustible gas sensor was developed by using nano crystalline $SnO_2$ Pt thin film as micro heater was deposited by thermal evaporation method on the alumina substrate. The thickness of the Pt heater was around 160 nm. The sensor showed high reliability with prominent selectivity against various gases(Co, $C_3H_8,\;CH_4$) at low operating temperature($156^{\circ}C$). The sensor with nano crystalline $SnO_2$ showed higher sensitivity than that without nano crystalline $SnO_2$. This can be explained by more active adsorption and oxidation of hydrogen by nano crystalline $SnO_2$ particles. The present planar-type catalytic combustible hydrogen sensor with nano crystalline $SnO_2$ is a good candidate for detection of hydrogen leaks.