• 한국가스학회지
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• 제27권3호
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• pp.41-51
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• 2023

지구 온난화로 인한 이상기후 현상이 빈번하게 발생함에 따라 많은 국가들이 탄소 중립을 선언하였고, 수소경제 사회로의 진입을 위해 노력하고 있다. 이때 암모니아는 수소 저장 밀도가 높아 수소 캐리어로써의 역할로 주목받고 있을 뿐만 아니라 무탄소 연료로써 활용의 역할도 주목받고 있다. 특히 암모니아 연료전지에 있어서, 음이온 교환막 연료전지에서는 별도의 암모니아 분해 장비나 수소 고순도화 장비가 필요 없이 암모니아를 바로 연료전지로 공급해 줄 수 있다는 장점이 있다. 따라서 본 연구에서는 이러한 음이온 교환막 연료전지의 작동 원리 및 연구 동향을 살펴보고 이를 바탕으로 음이온 교환막 연료전지에서 암모니아를 직접 연료로 활용한 연구 사례들을 알아보고자 한다.

• 반도체디스플레이기술학회지
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• 제12권2호
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• pp.33-37
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• 2013

In this study, we have investigated the effect of the substrate temperature and hydrogen flow rate on the characteristics of IZO thin films for the organic light emitting diodes (OLED) devices. For this purpose, IZO thin films were deposited by RF magnetron sputtering at room temperature and $300^{\circ}C$ with various $H_2$ flow rate. In order to investigate the influences of the oxygen, the flow rate of hydrogen in argon mixing gas has been changed from 0.1sccm to 0.9sccm. IZO thin films deposited at room temperature show amorphous structure, whereas IZO thin films deposited at $300^{\circ}C$ show crystalline structure having an (222) preferential orientation regardless of $H_2$ flow rate. The electrical resistivity of IZO film decreased with increasing flow rate of $H_2$ under Ar+$H_2$. The change of electrical resistivity with increasing flow rate of $H_2$ was mainly interpreted in terms of the charge carrier concentration rather than the charge carrier mobility. The electrical resistivity of the amorphous-IZO films deposited at R.T. was lower than that of the crystalline-IZO thin films deposited at $300^{\circ}C$. The increase of electrical resistivity with increasing substrate temperature was interpreted in terms of the decrease of the charge carrier mobility and the charge carrier concentration. All the films showed the average transmittance over 83% in the visible range.

• 반도체디스플레이기술학회지
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• 제15권4호
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• pp.46-50
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• 2016

In this study, we have investigated the effect of the substrate temperature and hydrogen flow rate on the characteristics of IGZO thin films for the TCO(transparent conducting oxide). For this purpose, IGZO thin films were deposited by RF magnetron sputtering at room temperature and $300^{\circ}C$ with various $H_2$ flow rate. In order to investigate the influences of the hydrogen, the flow rate of hydrogen in argon mixing gas has been changed from 0.1sccm to 1.0sccm. IGZO thin films deposited at room temperature show amorphous structure, whereas IGZO thin films deposited at $300^{\circ}C$ show crystalline structure having an (222) preferential orientation. The electrical resistivity of the amorphous-IGZO films deposited at R.T. was lower than that of the crystalline-IGZO thin films deposited at $300^{\circ}C$. The increase of electrical resistivity with increasing substrate temperature was interpreted in terms of the decrease of the charge carrier mobility. The transmittance of the IGZO films deposited at $300^{\circ}C$ was decreased deposited with hydrogen gas.

• 반도체디스플레이기술학회지
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• 제17권2호
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• pp.6-11
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• 2018

In this study, we have studied the effect of substrate temperature and hydrogen flow rate on the characteristics of MZO thin films for the TCO(Transparent conducting oxide). MZO thin films were deposited by RF magnetron sputtering at room temperature and $100^{\circ}C$ with various $H_2$ flow rate(1sccm~4sccm). In order to investigate the effect of hydrogen gas flow rate on the MZo thin film, we experimented with changing the hydrogen in argon mixing gas flow rate from 1.0sccm to 4.0sccm. MZO thin films deposited at room temperature and $100^{\circ}C$ show crystalline structure having (002), (103) preferential orientation. The electrical resistivity of the MZO films deposited at $100^{\circ}C$ was lower than that of the MZO film deposited at room temperature. The decrease of electrical resistivity with increasing substrate temperature was interpreted in terms of the increase of the charge carrier mobility and carrier concentration which seems to be due to the oxygen vacancy generated by the reducing atmosphere in the gas. The average transmittance of the MZO films deposited at room temperature and $100^{\circ}C$ with various hydrogen gas flow was more than 80%.

• 한국초전도ㆍ저온공학회논문지
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• 제25권4호
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• pp.65-69
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• 2023

Hydrogen is an eco-friendly energy source and is being actively researched in various fields around the world, including mobility and aerospace. In order to effectively utilize hydrogen energy, it should be used in a liquid state with high energy storage density, but when hydrogen is stored in a liquid state, BOG (boil-off gas) is generated due to the temperature difference with the atmosphere. This should be re-condensed when considering storage efficiency and economy. In particular, large-capacity liquid hydrogen storage tank is required a gaseous helium circulation cooling system that cools by circulating cryogenic refrigerant due to the increase in heat intrusion from external air as the heat transfer area increases and the wide distribution of the gas layer inside the tank. In order to effectively apply the system, thermo-hydraulic analysis through process analysis is required. In this study, the condenser design and system characteristics of a gaseous helium circulation cooling system for BOG recondensation of a liquefied hydrogen storage tank were compared.

• 한국가스학회지
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• 제25권6호
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• pp.85-91
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• 2021

정부는 2019년 1월 세계 최고 수준의 수소경제 선도국가로 도약하기 위해 「수소경제 활성화 로드맵」을 발표했으며, 우리나라가 강점이 있는 수소자동차와 연료전지를 양대 축으로 수소경제를 선도할 수 있는 산업생태계 구축 전략을 세웠다. 그 일환으로 2022년 310개소, 2040년 1,200개소의 수소충전소 보급목표를 수립하였다. 이에 발맞춰 2021년 2월 한국가스안전공사는 속도감 있는 수소충전소 구축을 위해 시공단계에서 안전기준에 따른 다양한 현장 문제 발생으로 인한 시공지연을 사전해소하기 위한 수소충전소 사전컨설팅 제도를 운영하게 된다. 본 논문은 사전컨설팅 제도에 대해 알아보고 그 효과를 분석하고자 한다.

• 한국표면공학회지
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• 제39권6호
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• pp.250-254
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• 2006

Effect of hydrogen partial pressure ratio on the structural and electrical properties of highly c-axis oriented ZnO films deposited by oxygen ion-assisted pulsed filtered vacuum arc at a room temperature was investigated. The hydrogen partial pressure ratio were $1.4%\sim9.8%$ at 40% oxygen pressure ratio. The conductivity of ZnO:H films was increased from 1.4% up to 4.2% due to relatively high carrier mobility caused by improvement of crystallinity While the conductivity of ZnO:H films were decreased over than 4.2% and (0002) orientation was also deteriorated. The lowest resistivity of ZnO:H films was $2.5{\times}10^{-3}\;{\Omega}{\cdot}cm$ at 4.2% of hydrogen pressure ratio. Transmittance of ZnO:H films in visible range was 85% which is lower than that of undoped ZnO films because of declined preferred orientation.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1911-1916
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• 2004

The conformational preference of tetrahomodioxacalix[4]arenes with three different para substituents on the phenolic ring has been investigated by using ab initio molecular orbital theory (RHF/6-31$G^{\ast}$) and density functional theory (B3LYP/6-31$G^{\ast}$). The stability order is predicted to be cone > C-1,2-alternate > partial cone > 1,3-alternate > COC-1,2-alternate. The distorted cone conformation is found to be most stable in a gas phase and the calculated results are in agreement with the reported $^1$H NMR and X-ray experimental observations. The substitution of methylene with dimethyleneoxa bridges increases the size of the annulus of the molecule, its conformational mobility, and the number of hydrogen bonding patterns. The thermodynamic stability and the conformational characteristics of tetrahomodioxacalix[4]arenes are discussed in regards of the number of phenolic hydrogen bonding patterns and the polarity of a molecule. The substituent effects on the para position of the phenolic ring are also introduced.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1023-1028
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• 2014

Protonated caffeine ($CH^+$) and glucosamine ($GH^+$) overlapped in an analysis with ion mobility spectrometryquadrupole mass spectrometry. Ethyl lactate vapor (L) at different concentrations from 0 to 22 mmol $m^{-3}$ was added as a buffer gas modifier to separate these signals. The drift times of $CH^+$ and $GH^+$ increased with L concentration. The drift time increase was associated to clustering equilibria of $CH^+$ and $GH^+$ with one molecule of L and the equilibrium of $GH^+$ was more displaced to the formation of $GLH^+$ than that of $GLH^+$. $GH^+$ clustered more to L than $CH^+$ because $GLH^+$ formed more stable hydrogen bonds (26.30 kcal/mol) than $GLH^+$ (24.66 kcal/mol) and the positive charge in $GH^+$ was more sterically accessible than in $CH^+$. The aim of this work was to use theoretical calculations to guide the selection of a buffer gas modifier for IMS separations of two compounds that overlap in the mobility spectra and predict this separation, simplifying that empirical process.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.668-672
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• 2003

In order to reach the high electrical quality of organic thin film transistors (OTFTs) such as high mobility and on-off current ratio, it is strongly desirable to study the enhancement of electrical properties in OTFTs. Here, we report the novel method of hydrogen $(H_{2})$ plasma treatment to improve electrical properties in inverted staggered OTFTs based on pentacene as active layer. To certify the effect of this method, we compared the electrical properties of normal device as a reference with those of device using the novel method. In result, the normal device as a reference making no use of this method exhibited a field effect mobility of 0.055 $cm^{2}/Vs$, on/off current ratio of $10^{3}$, threshold voltage of -4.5 V, and subthreshold slope of 7.6 V/dec. While the device using the novel method exhibited a field effect mobility of 0.174 $cm^{2}/Vs$, on/off current ratio of $10^{6}$. threshold voltage of -0.5 V, and subthreshold slope of 1.49 V/dec. According to these results, we have found the electrical performances in inverted staggered pentacene TFT owing to this novel method are remarkably enhanced. So, this method plays a key role in highly improving the electric performance of OTFTs. Moreover, this method is the first time yet reported for any OTFTs