• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.674-683
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• 2022

In this study, we examined the case of Fukushima Hydrogen Research Field (FH2R) Namie hydrogen town. We found that the case has three aspects of socio-technical experiment: a living-scale test-bed of hydrogen technologies, activities for enhancing social acceptability, and a designed module for policy transfer to diffuse. This study aims to provide a benchmark for planning a green hydrogen city in near future.

• 한국가스학회지
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• 제19권6호
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• pp.85-91
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• 2015

전 세계적으로 수소에너지에 대한 관심이 점차 증가함에 따라 수소 생산, 저장, 운송, 이용 분야에서 응용 기술의 개발이 활발히 진행되고 있다. 국내에서도 울산 수소타운을 조성하여 시범운영 중에 있어 수소에너지 응용처 확대에 대한 가능성을 높이고 있다. 울산 수소타운은 가스 사용 압력에 따라 고압부와 저압부로 구분할 수 있는데 고압부는 '고압가스안전관리법'을 적용하여 안전관리를 하고 있고 저압부는 '수소타운 시범사업의 안전관리에 관한 지침'을 적용하여 운영 중에 있다. 본 논문에서는 울산 수소타운 내 0.1MPa 이하 저압 수소 사용시설의 안전관리 효율성 향상을 위해 저압 수소사용 시설 및 안전관리 항목 분석을 통해 안전관리 방향성을 검토하고 향후 개선 방향을 제시하고자 하였다. 본 연구의 결과를 통해 국내 수소타운 활성화 및 안전 관리 효율성 증대에 도움이 될 수 있을 것으로 기대한다.

• 한국수소및신에너지학회논문집
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• 제27권6호
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• pp.685-692
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• 2016

Hydrogen will be a future eco-friendly energy source that can replace current fossil fuels However when hydrogen gas leaks and people inhale a lot of hydrogen gases, they can have fatal effects fell into comas. Therefore, we need to develop a safety technology and related guidelines for reducing risks of hydrogen leakage. In this regard, we carried out demonstration tests assuming a situation of hydrogen leakage. Before the experiments, we analyze the standards for governor facilities to check vent positions and sensor positions. Then, we select four types of ventilation structures and proceeds with the experiments of hydrogen leakage at 1 LPM and 1.5 LPM. Based on the experimental results, we propose the direction on optimization of vent positions and sensor positions in the hydrogen leakage situation.

• 한국수소및신에너지학회논문집
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• 제27권6호
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• pp.670-676
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• 2016

Hydrogen town in Republic of Korea was established in 2013. Hydrogen as a byproduct produced by various processes of factories is used in hydrogen town facilities. As cell performance is affected by contaminations in fuel gas, various standards about impurities of fuel have been determined by many countries. This study shows performance degradation of single cell with impurities concentrations. Traces of carbon monoxide (CO) and hydrogen sulfide ($H_2S$)can cause considerable cell performance losses. For comparing the performances by poisoning of CO, acceleration test, I-V curve, constant current are performed. Both the CO and $H_2S$ poisoning rate are a function of their concentration. With the higher concentrations the higher poisoning rates are observed. And, it was confirmed that, oxidation behavior and side reaction generation are not affected. Under the lower $H_2S$ concentration condition, the poisoning rate is much higher than that of CO because of its different adsorption intensity. It can be possible that the result of this study can be used for enacting regulation as a baseline data.

• 한국수소및신에너지학회논문집
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• 제1권1호
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• pp.9-14
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• 1989

Mixed photocatalyst containing cadmium sulfide and zinc sulfide was prepared on silica gel powder and Nafion film. Photo-irradiation of aqueous mixture containing the photocatalysis generated hydrogen by water cleavage reaction. Use of sodium sulfide as sacrificial reagent help the photo-reaction. Evolution of the hydrogen was measured by gas chromatographic analysis. Composition of the catalyst was determined by atomic absorption spectrophotometer. 0.2 mL of of hydrogen was generated per hour. The maximun catalytic activity was obtained after 8-12 hours later. Hydrogen generation efficiency by the two different catalytic system was compared and showed that the Nafion-based catalyst is more efficient than the silicagel-based catalyst for the photoreaction.

• 한국수소및신에너지학회논문집
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• 제25권2호
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• pp.161-172
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• 2014

Hydrogen, which can be produced from abundant and widely distributed renewable energy resources, seems to be a promising candidate for solving the concerns for improving energy security, urban air pollution, and reducing greenhouse gas emissions. The two primary motivating factors for hydrogen economy are fossil fuel supply limitations and concerns about global warming. But the safety issues associated with hydrogen economy need to be investigated and fully understood before being considered as a future energy source. Limited operating experience with hydrogen energy systems in consumer environments is recognised as a significant barrier to the implementation of hydrogen economy. To prevent unnecessary restrictions on emerging codes, standards and local regulations, safety policies based on real hazards should be developed. This article studies briefly the direct impact-distances from hazard events such as hydrogen release and jet fire, and damage levels from hydrogen gas explosion in a confined space. Based on the direct impact-distances indicated in the accident scenarios and consumer environments in Korea, the safety policies, which are related to hydrogen filling station, hydrogen fuel cell car, portable fuel cell, domestic fuel cells, and hydrogen town, are suggested to implement hydrogen economy. To apply the safety policies and overcome the disadvantages of prescriptive risk management, which is setting guidance in great detail to management well known risk but is not covering unidentified risk, hybrid risk management model is also proposed.

• 한국축산식품학회지
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• 제31권6호
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• pp.893-898
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• 2011

Milk contains a number of nutrients required for human growth and development, such as disaccharide lactose which is significantly contained in milk and dairy products. About two thirds of world populations are reportedly suffering from lactose intolerance after drinking milk. Lactose intolerance is defined as a maldigestion of lactose in the human intestine with typical symptoms of abdominal pains, bloating, and diarrhea. In this study, incidence of lactose intolerance has been investigated for the elementary school children for 1 year from July, 2010 to June, 2011. It is found that about 70% of the total elementary students have joined the school milk program. Out of 636 total students that participated in this study, 449 were from the metropolis, 85 from middle-sized city, and 102 from the small town including rural areas (small town/rural areas). For distributions of lactose intolerance, 154 students (24.2%) were found to be positive among the total 636 subjects. Based on the size of the city, the symptoms were the most prevalent for the students in the small town/rural areas at 31.4% (32/102), followed by 30.6% (26/85) in middle-sized city, and 21.4% (96/449) in the metropolis. On the other hand, gender had no significant effect on the incidence of lactose intolerance, shown those for boys and girls were 24.8% (77/310), 23.6% (77/326), respectively. Further research is needed to confirm the correct incidence of lactose intolerance symptoms as the frequency is significantly affected by subject's digestive functions including irritable bowel syndrome.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.109-114
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• 2008

This paper presents the development status of a subscale precooled turbojet engine "S-engine" for the hypersonic cruiser and space place. S-engine employs the precooled-cycle using liquid hydrogen as fuel and coolant. It has $23cm{\times}23cm$ of rectangular cross section, 2.6 m of the overall length and about 100 kg of the target weight employing composite materials for a variable-geometry rectangular air-intake and nozzle. The design thrust and specific impulse at sea-level-static(SLS) are 1.2 kN and 2,000 sec respectively. After the system design and component tests, a prototype engine made of metal was manufactured and provided for the system firing test using gaseous hydrogen in March 2007. The core engine performance could be verified in this test. The second firing test using liquid hydrogen was conducted in October 2007. The engine, fuel supplying system and control system for the next flight test were used in this test. We verified the engine start-up sequence, compressor-turbine matching and performance of system and components. A flight test of S-engine is to be conducted by the Balloon-based Operation Vehicle(BOV) at Taiki town in Hokkaido in October 2008. The vehicle is about 5 m in length, 0.55 m in diameter and 500 kg in weight. The vehicle is dropped from an altitude of 40 km by a high-altitude observation balloon. After 40 second free-fall, the vehicle pulls up and S-engine operates for 60 seconds up to Mach 2. High altitude tests of the engine components corresponding to the BOV flight condition are also conducted.

• 자원환경지질
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• 제51권6호
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• pp.567-577
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• 2018

우리나라에서 수막재배가 주로 이루어지는 수변지역에서는 수막재배 성수기 말기에 지하수위 하강이 심하게 나타나는 문제점이 있으며, 이러한 지하수위 하강과 지하수 자원 고갈의 문제는 인근 하천수와의 연계 특성을 고려할 때 효율적으로 해결할 수 있을 것이다. 이 연구에서는 수막재배지에서의 지하수와 하천수와의 연계성 및 지하수 대수층에 미치는 하천수의 영향 범위를 논의하기 위해, 지하수의 토출온도, 지하수와 하천수의 산소 수소 안정동위원소 조성 변화 특성을 검토하였다. 연구지역은 딸기 수막재배지로 잘 알려진 논산시 광석면 왕전리 지역이며, 지하수와 하천수의 시료 채취는 2010년 2월부터 2011년 6월까지 실시되었다. 지하수의 수온 분포 패턴에 의하면, 하천수의 영향은 주로 수막재배지의 우측 부분에서 넓은 범위에 걸쳐 나타났으며, 좌측 부분은 하천 인근에서만 좁은 범위의 영향을 받고 있는 것으로 나타났다. 이러한 현상은 수막재배지 내에서 산출되는 지하수의 산소 수소 안정동위원소 조성에서도 유사한 양상으로 나타났다.

• 대한화학회지
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• 제44권1호
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• pp.10-16
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• 2000

일반적으로 산성비는 이온세기가 낮아 저항이 크고 완충능이 없는 용액이다. 그러므로 산성비의 pH측정 시, 시료용액의 액간접촉전위는 이온세기의 차이로 인해 pH표준용액의 액간접촉전위와 달라서 pH 측정값에 오차가 발생될 수 있다. 실제 1998년도 대덕연구단지에 내린 빗물의 평균 전도도 값이 12.8 ${\mu}S/cm$인데 비해, pH 표준용액의 전도도 값은 약 5,980 ${\mu}S/cm$으로 이온세기의 차이가 크다. 본 연구에서는 산성비의 pH를 측정할 때 액간접촉전위로 인해 발생되는 오차를 보정하기 위해, 빗물과 비슷한 pH와 전도도를 가지는 묽은 황산의 물성조절표준물(Quality Control Standard, 이하 QCS로 표기)을 제조하여 사용하였다. QCS의 pH값을 액간접합이 없는 수소전극 시스템으로 인증한 다음, 유리전극으로 다시 pH를 측정하여 그 차이값 만큼 보정하였다. 아울려 이 방법으로 1998년도 대덕연구단지에 내린 빗물의 pH를 측정하였다.