• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.210-217
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• 2021

Gas sensors based on semiconducting metal oxides have attracted considerable attention for various applications owing to their facile, cheap, and small-scale manufacturing processes. Hematite (α-Fe₂O₃) is widely considered as a promising candidate for a gas-sensing material owing to not only its abundance in the earth's crust and low price but also its chemical stability and suitable bandgap energy. However, only a few studies have been performed in this direction because of the low gas response and sluggish response of hematite-based gas sensors. Nanostructures present a representative solution to both overcome these disadvantages and exploit the desirable features to produce high-performance gas sensors. However, several challenges remain for adopting gas sensors based on metal oxide nanostructures, such as improving cost efficiency and facilitating mass production. This review summarizes the recent studies on gas sensors based on hematite nanostructures. It also provides useful insights into various strategies for enhancing the gas-sensing properties of gas sensors based on hematite nanostructures.

• Journal of the Korean Institute of Gas
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• v.5 no.1
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• pp.52-59
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• 2001

Factors to cause accidents were investigated through a systematic analysis of leakage accidents in welded LP-gas cylinder between 199 and 1999. As a result It was showed that most of leakage accident occurred at the pin-hole due to the localized corrosion on welded zone in cylinder. Accordingly, in this paper, we suggested that the problems of heat treatment condition in two-piece welded cylinder and substitute proposal for preventing the tearing of T zone in three-piece welded cylinder. Furthermore, corrosion rate on the weldment and base metal of welded LP-gas cylinder was evaluated using the electrochemical tests in acid rain and $3.5\%NaCl$ solution, Also, the poor adhesion and defects of film which was produced by electrostatic powder spray painting, while the LP-gas cylinder was manufactured, were analyzed using SEM(Scanning Electron Microscopy). And we proposed a optimum coating thickness of the cylinder.

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.26-30
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• 2011

Instantaneous water heater being not properly installed and not adequately maintained may produce fatal accidents due to carbon monoxide poisoning and suffocation. Insufficient supply of air into the gas appliance for complete burning of the fuel or blocking the outlet of the combustion gas could be a cause to increase carbon monoxide concentration in the exhaust gas of the gas appliance. In this work, the experiments are done with a collected instantaneous water heater using in domestic and the concentration of oxygen near the gas appliance and carbon monoxide in exhaust gas are observed to investigate the risk of instantaneous water heater. The concentration of oxygen near the gas appliance is reduced until 17.7% for the ratio of the ventilation area and floor area being 3.5%. If the outlet of combustion gas is blocked, the carbon monoxide concentration is steeply increasing more than 4,000ppm. Therefore, periodic checking the outlet of combustion gas is more important than vent area to reduce the risk of carbon monoxide poisoning.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.5
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• pp.312-316
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• 2016

In this study, we fabricated $NO_x$ gas sensor by using multi-walled carbon nanotubes(MWCNT)/zinc oxide(ZnO) composite film. Carbon nanotubes (CNTs) have good electronic, chemical-stability, and sensitivity characteristics. And zinc oxide (ZnO) is a wide band gap and large exciton binding energy semiconductor. In particular, gas sensors require characteristics such as high speed, sensitivity, and selectivity. The fabricated gas sensor was used to detect $NO_x$ gas for different values of the $NO_x$ gas concentrations. The gas sensor that absorbed$NO_x$ gas molecules showed a increasing in resistance. The sensitivity of the gas sensor was increased by increasing the gas concentrations. Additionally, while changing the temperature inside the chamber for the MWCNT/ZnO composite film gas sensor, we obtained the sensitivity. And the comparison analysis to ZnO film gas sensor for detecting $NO_x$ gas. From the experiment result, we confirmed improvement of $NO_x$ gas detection characteristics using the MWCNT/ZnO composite film.

• Journal of Korean Institute of Fire Investigation
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• v.11 no.1
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• pp.59-65
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• 2008

Among the various cases of fire accident, gas accident which is roost essential have a lot of forms and causes. The quantity consumed of gas is increasing because of increment of gas-using families and variations of gas machinery. The quantity consumed of gas in 2007 was 35078 tons and the average rate of increasement was 9.4%. The amount of gas accident was on the peak at 1995 when 557 accidents occurred in a year. In 2007, 123 gas accidents was occurred and the average rate of diminution was 11.5%. Accidents by LP gas took 80% of the whole accident and city gas and high pressure gas took 20%. In case of LP gas, accidents were usually occurred because of lack of blocking after the removal of gas machinery and moveable butane burner. Especially, the accidents cause by carelessness of a provider is increasing. Gas accidents which generate damage of human life and property, are caused by users' carelessness, providers' carelessness, inferiority of structure and old products. In this thesis, We will classify the gas accidents. Furthermore through the classification of accidents by forms, causes and regions, this thesis going to be a reference to understand and prevent the accidents.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.9
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• pp.430-435
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• 2002

The $SF_{6}$ gas insulated power equipments have the insulation systems which are composed of $SF_{6}$ gas and insulation paper. It is repored that their insulation abilities are influenced by the $SF_{6}$ gas gaps in those insulation systems and gas pressures. This paper describes partial discharge phenomena with $SF_{6}$ gas pressures in insulation system of $SF_{6}$ gas-insulation paper Specimens of $SF_{6}$ gas-insulation paper were prepared and aramid paper was used as insulation paper. Partial discharge inception voltages(PDIV) and breakdown voltages for the existence of $SF_{6}$ gas gaps were measured by short term tests with gas pressures. Also, average PD quantities and pulse counts, life times of each specimens were calculated from the results of long term aging tests with gas pressures. It was found that the $SF_{6}$ gas gaps decrease increasing rates of PDIV and brealdown voltages according to gas pressure increase and the insulation breakdown caused by the smaller PD quantities than 1[pC] at the high gas pressure of 300kPa is due to the increase of energy density with increase of gas pressure.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.12
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• pp.525-534
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• 2023

Gas leak detection system is a key to minimize the loss of life due to the explosiveness and toxicity of gas. Most of the leak detection systems detect by gas sensors or thermal imaging cameras. To improve the performance of gas leak detection system using single-modal methods, the paper propose multimodal approach to gas sensor data and thermal camera data in developing a gas type identification model. MultimodalGasData, a multimodal open-dataset, is used to compare the performance of the four models developed through multimodal approach to gas sensors and thermal cameras with existing models. As a result, 1D CNN and GasNet models show the highest performance of 96.3% and 96.4%. The performance of the combined early fusion model of 1D CNN and GasNet reached 99.3%, 3.3% higher than the existing model. We hoped that further damage caused by gas leaks can be minimized through the gas leak detection system proposed in the study.

• 한국가스학회:학술대회논문집
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• 1997.09a
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• pp.183-188
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• 1997

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.281-286
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• 1998

• 한국가스학회:학술대회논문집
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• 2001.10a
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• pp.87-97
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• 2001