• 센서학회지
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• 제30권6호
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• pp.376-380
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• 2021

The accurate detection of hydrogen gas molecules is considered to be important for industrial safety. However, the selective detection of the gas using semiconductive metal oxides (SMOs)-based sensors is challenging. Here, we describe the fabrication of H₂ sensors in which a nanocellulose/graphene oxide (GO) hybrid membrane is attached to SnO₂ nanosheets (NSs). One-dimensional (1D) nanocellulose fibrils are attached to the surface of GO NSs (GONC membrane) by mixing GO and nanocellulose in a solution. The as-prepared GONC membrane is employed as a sacrificial template for SnO₂ NSs as well as a molecular sieving membrane for selective H₂ filtration. The combination of GONC membrane and SnO₂ NSs showed substantial selectivity to hydrogen gas (R_air / R_gas > 10 @ 0.8 % H₂, 100 ℃) with noise level responses to interfering gases (H₂S, CO, CH₃COCH₃, C₂H₅OH, and NO₂). These remarkable sensing results are attributed mainly to the molecular sieving effect of the GONC membrane. These results can facilitate the development of a highly selective H₂ detector using SMO sensors.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.67-70
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• 2002

The Stirling cryocooler with helium refrigerant has been widely used for the cooling of the infrared detector, and the alternatives of the helium in the Stirling cryocooler are nitrogen and hydrogen gas. In this study, the performance experiment of the small FPFD(Free Piston and Free Piston) type Stirling cooler and the moving coil type, dual acting linear compressor was performed when the nitrogen and helium is used for the working fluid The results show that the nitrogen refrigerant has small cooling capacity compared with the helium, but the performance characteristics of the linear compressor does not greatly changed.

• 천문학회지
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• 제36권spc1호
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• pp.145-149
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• 2003

LIST is the Lyman-$\alpha$ Imaging Solar Telescope, a project funded by the Korean government to fly on the second Korean Science and Technology research Satellite (STSat-2) due to launch in December 2005. The Principal Investigator is Dr. Minhwan Jang of Kyung-Hee University and of the Space Payload Research Center (SPARC), a consortium of Korean universities and institutions formed to develop scientific research projects in space. The purpose of the LIST project is to design, build, and operate an instrument on STSat-2 which will make images of the Sun from Earth orbit at the wavelength of the Hydrogen Lyman-a emission line at 121.6 nm. LIST has a simple design concept comprised of a small telescope to image the full disk of the Sun onto a CCD detector and a set of filters to isolate the 121.6 nm wavelength.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.323-324
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• 2005

To found out the degradation characteristic of transformer insulation, insulation materials and electrodes are deposited into transformer oil. They used to heated and make flashover. Due to the thermal and electrical stress added to insulation materials, the density of carbon dioxide and hydrogen included in transformer oil was increased. The gas density can measured by using the gas density detection equipment of gas sensor and air circulation method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1846-1849
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• 2000

Off-line and on-line partial discharges were measured on a 828MVA, 22kV and direct hydrogen-cooled large turbine generator. Partial discharge tests were conducted using digital partial discharge detector(PDD) and turbine generator analyzer(TGA). PDD and TGA showed that off-line partial discharge pattern seems to be very, similar to that found with on-line. Most of the partial discharge is originating with the stator slot in the three phases. As the partial discharge activity is very low, the stator insulation condition of this generator is very good.

• 센서학회지
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• 제7권3호
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• pp.163-170
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• 1998

플라즈마 이온온도를 측정하기 위해 정전평판형 이온에너지 분석기를 설계 제작하고 에너지 교정 및 에너지 분해능 등의 특성을 조사하였다. 일정한 검출기 위치에서 이온의 에너지에 따른 편향평판전압은 선형성을 보였으며, $53{\sim}103mm$ 사이의 검출기 위치에서 이온에너지에 대한 최대편향평판전압의 기울기는 $1.61{\sim}0.92$로 검출기위치의 증가에 따라 선형적으로 감소하였다. 본 실험 영역에서 에너지 분해능은 약 $4.16{\sim}11.60%$였으며, 검출기 위치 및 이온에너지의 증가에 따라 향상되었다. 상대적 검출효율은 검출기 위치의 증가에 따라 감소하였다. 제작된 분석기를 다목적 플라즈마 발생장치에 설치하여 DC 플라즈마의 이온에너지 스펙트럼을 측정하였다. 방전전압이 320V, 전류가 0.17A인 DC 플라즈마의 이온온도는 $203{\sim}205eV$로 나타났으며 검출기의 위치에 따른 이온온도의 변화는 없었다. 검출기의 위치에 따른 에너지 분해능은 $18{\sim}21%$로 검출기 위치가 증가할수록 향상되었다.

• 센서학회지
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• 제23권5호
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• pp.342-348
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• 2014

This paper introduced a novel multi-gas sensor detector with simple signal processing algorithm. This device was evaluated by investigating the characteristics of combustible materials using fire-generated smell and smoke. Plural sensors including TGS821, TGS2442, and TGS260X were equipped to detect carbon monoxide, hydrogen gas, and gaseous air contaminants which exist in cigarette smoke, respectively. Signal processing algorithm based on the difference of response times in fire-generated gases was implemented with early and accurately fire detection from multiple gas sensing signals. All fire experiments were performed in a virtual fire chamber. The cigarette, cotton fiber, hair, polyester fiber, nylon fiber, paper, and bread were used as a combustible material. This analyzing software and sensor controlling algorithm were embedded into 8-bit micro-controller. Also the detected multiple gas sensor signals were simultaneously transferred to the personnel computer. The results showed that the air pollution detecting sensor could be used as an efficient sensor for a fire detector which showed high sensitivity in volatile organic compounds. The proposed detecting algorithm may give more information to us compared to the conventional method for determining a threshold value. A fire detecting device with a multi-sensor is likely to be a practical and commercial technology, which can be used for domestic and office environment as well as has a comparatively low cost and high efficiency compared to the conventional device.

• Applied Biological Chemistry
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• 제12권
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• pp.43-51
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• 1969

우리나라 주요 식품들의 단백질 아미노산 함량을 최근에 와서 크게 실용화되고 있는 GLC 방법에 의해 분석함에 있어서 GLC의 기술적 재평가를 하고자 시험 하였든바 1. 우선 여러식품들의 단백질 질소함량을 조사하여 GLC 분석에 필요한 시료량을 정하였으며 2. GLC에 주입한 17종 아미노산들이 대하여 조사한 결과 Arginine, Cystine, Histidine, Tyrosine을 제외한 13종만이 주입한 량에 비례하여 detector response 를 얻었다. 3. 13종 아미노산에 대한 RMR 치(値)를 얻었다. 4. 아미노산에 대한 recovery 검정(檢定)을 하였든바 거의 100% 가까이 recover되었으며, 가수분해가 recovery에 미치는 영향을 조사하였든바 별 영향이 없었음을 알았다. 5. GLC와 ion-exchange chromatography 분석법을 비교시험하였든바 백어포 시료에 있어서는 Threonine과 Asparagine만이 두 방법에서 거의 같게 나왔고 다른 아미노산들은 GLC에서 보다 많은량이 나타났다. 6. 각식품들에 대한 단백질 아미노산함량을 측정하였든바 식품종류에 따라 그리고 보리 및 대두에 있어서는 품종에 따라서도 아미노산 함량이 다르게 나타났다.

• 분석과학
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• 제7권3호
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• pp.349-359
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• 1994

천연가스 중의 부취제 농도를 분석하기 위한 기체 크로마토그래피 방법에 대하여 연구하였다. TBM(tertiarybutylmercaptan) 및 THT(tetrahydrothiophene)를 포함한 8종의 부취제를 OV-101 컬럼상에서 거의 완전히 분리하였다. 수소 유속, 공기 유속 및 검출기 온도와 같이 FPD의 응답에 영향을 미치는 몇 가지 상호 관련된 파라미터들의 최적 조건을 구하였다. TBM과 THT의 검정곡선을 투과한 장치를 이용하여 작성하였다. 이러한 분석방법을 천연가스 공급관 내의 혼합 부취제인 TBM과 THT를 정량하는 데 적용하였다. 부취수준과 부취제 농도와의 상관관계를 구하기 위한 냄새 측정기의 유용성에 대하여 알아보았다.

• KSBB Journal
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• 제30권4호
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• pp.161-165
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• 2015

Lactic acid and its derivatives are widely used in the food, pharmaceutical, and cosmetic industries. It is also a major raw material for the production of poly-lactic acid (PLA), a biodegradable and environmentally friendly polymer and a possible alternative to synthetic plastics derived from petroleum. For PLA production by new strains of lactic acid bacteria (LAB), we screened LAB isolates from shellfish. A total of 51 LAB were isolated from 7 types of shellfishes. Lactic acid production of individual isolates was examined using high-performance liquid chromatography using a Chiralpak MA column and an ultraviolet detector. Lactobacillus plantarum T-3 was selected as the most stress-resistant strain, with minimal inhibition concentrations of 1.2 M NaCl, 15% ethanol, and 0.0020% hydrogen peroxide. In a 1 L fermentation experiment, $\small{D}$-lactic acid production of 19.91 g/L fermentation broth was achieved after 9 h cultivation, whereas the maximum production of total lactic acid was 41.37 g/L at 24 h.