• Journal of Radiation Protection and Research
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• 제17권1호
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• pp.31-41
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• 1992

라돈 자핵종의 알파 측정용 여과지 매질에 대한 평가를 위한 연구는 물리적 특성조사로 여과지의 정전하 충전과 역학적 강도가 조사된 후, 시료채취 전과 후 여과지에 부가되는 압력차로 여과지의 성질을 시험하였으며, 알파 스팩트럼분석으로 여과지내 부착된 라돈 자핵종의 에너지스펙트럼을 분석하여 성능지수를 계산한 후 여과지의 특성을 비교 평가하였다. 평가의 결과 새로운 여과지 매질은 과거의 표준인 Millipore AA보다 크게 유리한 점은 없었으나, 정전하가 문제되는 곳에서는 Metricel DM-800을 권고하였다. 또한 평가방법은 새로 개발될 여과지들의 물리적 특성과 매질의 수집효율을 고려하여 라돈 자핵종의 알파 측정용 여과지 매질 평가를 위해 유용하게 사용될 수 있을 것이다.

• 한국수소및신에너지학회논문집
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• 제35권1호
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• pp.83-89
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• 2024

In order to confirm the safety against vibration of high-pressure fittings for mobile hydrogen charging devices, the natural frequency was confirmed through ANSYS, and vibration data occurring during driving was applied to utilize the vehicle's operating power spectral density data specified in MIL-STD-810H regulations. Fatigue analysis and resonance were confirmed, and as a result, it was confirmed that the sum of the pure phase ratios was less than 1 for the driving history presented in the standard, and there was no risk of resonance.

• 한국수소및신에너지학회논문집
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• 제30권1호
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• pp.29-34
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• 2019

Safety of hydrogen handling facilities is needed as supply of hydrogen cars has been expanded recently. In this study, the adequacy of safety regulations of hydrogen handling facilities and the risk of damage with hydrogen leakage were studied. The range of explosion hazard location of the hydrogen filling plant was investigated using the computational fluid dynamics (CFD) method, Explosive hazardous area is influenced by leakage type, hole size and sectional area. When the conditions of KS standard are applied, range explosive hazardous area is expanded 7.05 m, maximum. It is about 7 times larger than exceptional standard of hydrogen station. Meanwhile, distance from leakage point to 25% LEL of hydrogen is investigated 1.6 m. Considering the shape of charging hose, regulation of hydrogen station is appropriate.

• 한국재료학회지
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• 제31권2호
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• pp.75-83
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• 2021

To cope with automobile exhaust gas regulations, ISG (Idling Stop & Go) and charging control systems are applied to HEVs (Hybrid Electric Vehicle) for the purpose of improving fuel economy. These systems require quick charge/discharge performance at high current. To satisfy this characteristic, improvement of the positive electrode plate is studied to improve the charge/discharge process and performance of AGM(Absorbent Glass Mat) lead-acid batteries applied to ISG automotive systems. The bonding between grid and A.M (Active Material) can be improved by applying the Sand-Blasting method to provide roughness to the surface of the positive grid. When the Sand-Blasting method is applied with conditions of ball speed 1,000 rpm and conveyor speed 5 M/min, ideal bonding is achieved between grid and A.M. The positive plate of each condition is applied to the AGM LAB (Absorbent Glass Mat Lead Acid Battery); then, the performance and ISG life characteristics are tested by the vehicle battery test method. In CCA, which evaluates the starting performance at -18 ℃ and 30 ℃ with high current, the advanced AGM LAB improves about 25 %. At 0 ℃ CA (Charge Acceptance), the initial charging current of the advanced AGM LAB increases about 25 %. Improving the bonding between the grid and A.M. by roughening the grid surface improves the flow of current and lowers the resistance, which is considered to have a significant effect on the high current charging/discharging area. In a Standard of Battery Association of Japan (SBA) S0101 test, after 300 A discharge, the voltage of the advanced AGM LAB with the Sand-Blasting method grid was 0.059 V higher than that of untreated grid. As the cycle progresses, the gap widens to 0.13 V at the point of 10,800 cycles. As the bonding between grid and A.M. increases through the Sand Blasting method, the slope of the discharge voltage declines gradually as the cycle progresses, showing excellent battery life characteristics. It is believed that system will exhibit excellent characteristics in the vehicle environment of the ISG system, in which charge/discharge occurs over a short time.

• 설비공학논문집
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• 제6권3호
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• pp.237-246
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• 1994

Experimental data are reported for charging and collection of NaCl aerosols in the 0.03- to $0.2{\mu}m$-geometric-mean-diameter range in 2-stage parallel-plate electrostatic precipitators. The NaCl aerosols are generated with geometric standard deviation of about 1.74 and particle generation rate of about 10^9 particles/see by the constant output atomizer and injected into the air flow in the clean wind-tunnel. The 2-stage parallel-plate electrostatic precipitator installed in the test section of the wind-tunnel is operated with a positive corona discharge. The NaCl aerosols in the channel flow are sampled and transported to the aerosol particle number concentration measurement system by using the isoaxial sampling and transport system constructed based on the Okazaki and Willeke design. The aerosol particle number concentration measurement system measures the size distribution of submicrometer aerosols by an electrical mobility detection technique. It is confirmed from comparing the measured collection efficiencies in this study and the predicted ones by our previous theoretical analysis that the predicted collection efficiencies agree well with the experimental ones. It is also found from the comparison that below about $0.02{\mu}m$ all particles are not charged and the uncharged particles are not collected, and consequently 2-stage parallel-plate electrostatic precipitators are not suitable for that particle size range.

• 생명과학회지
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• 제34권8호
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• pp.588-593
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• 2024

대사경로 3,490개가 고세균 471종에 분포하는 정도를 MetaCyc database의 자료를 이용하여 분석하였다. 대사경로의 수는 고세균의 종류에 따라 13~184개가 존재하였다. 모든 고세균에 공통적으로 존재하는 대사경로는 없었으며 470종의 고세균에 UTP and CTP de novo biosynthesis와 tRNA charging의 대사경로가 존재하였다. 고세균들에 분포하는 상위 12개의 대사경로 중에서 핵산관련이 5개, 단백질관련이 5개 그리고 생체의 여러 반응에 참여하는 cofactor인 S-adenosyl-L-methionine (SAM)의 생합성 대사경로와 효소의 활성에 필수적인 번역 후 변형에 필요한 phosphopantothenate biosynthesis III (archaea)의 대사경로로 나타나 핵산과 물질대사와 관련된 단백질의 중요성을 알 수 있었다. 대사경로 보유 계통수에서 구한 distance value를 이용하여 고세균의 각 강(class)을 평균과 표준편차로 나누었을 때, 2개의 그룹과 기타로 나뉘어져 대사경로의 분포가 다양한 것으로 나타났다. 본 연구결과는 기초과학 이외에 약물개발 등에도 응용될 수 있을 것으로 기대된다.

• 터널과지하공간
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• 제21권2호
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• pp.103-108
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• 2011

콘크리트 블록에 대한 붙이기 발파실험과 더불어 콘크리트 박스거더 교량의 모형에 대하여 발파해체 실험을 실시하였다. 장약으로는 폭발위력의 기준 약으로 사용되는 TNT를 사용하였다. 실험결과 콘크리트 박스거더 교량의 경우 폭약설치지점의 폭발력뿐 만 아니라 박스거더 내부 벽에 작용하는 폭풍압도 해체에 영향을 미치는 것으로 나타났다.

• 화약ㆍ발파
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• 제14권4호
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• pp.4-12
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• 1996

본 논문은 10월 29일 서울교육문화원 강당에서 한화가 주최한 바 있는 제1회 한화 기술 심포지움에 초청강사로서 발표한 내용을 요약한 것이다.

• 에너지공학
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• 제28권4호
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• pp.1-7
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• 2019

최근 수소충전소 수요 증가에 따라, 산업통상자원부는 LPG, CNG, 주유소 등 기존의 자동차용 연료공급시설 내에 융합, 복합의 형태로 수소충전소 설치가 가능하도록 특례고시를 제정·공포하였다. 수소 융복합충전소는 특례기준 제정 이전까지 국내에서 운영된 사례가 없어, 4계절, 일교차와 같은 환경특성을 감안한 실증이 필요하다. 본 연구에서는, 국내 최초로 실증을 위해 설치된 울산 LPG-수소복합충전소의 충전데이터를 수집하여 분석하였다. 충전데이터는 압축기, 저장용기, 디스펜서에서 발생한 시간별 온도, 압력 데이터이며, 계절별 특성을 비교하기 위해 2018년 7월 중 울산 지역의 최고기온 일과 2018년 1월 중 최저기온 일을 포함하여 4계절 충전데이터를 수집하여 비교하였다. 비교결과, 외기온도의 변화가 수소차 차량용기의 초기온도에 영향을 미치는 것으로 나타났으며, 이는 최종적으로 차량의 충전시간과 충전속도에도 영향을 미치는 것으로 나타났다. 국내 수소충전소 기준(KGS FP217)과 미국의 충전프로토콜(SAE J2601)에서 제시한 한계온도를 초과한 경우는 없어 차량용기에 대한 영향은 없는 것으로 나타났다.

• 한국환경과학회지
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• 제13권1호
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• pp.99-107
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• 2004

This research is to determine the level of environmental pollution at a blasting construction area which is the origin of noise, vibration, and suspended particle, and to compare the results with other domestic and international standard data. This experiment is also to find out the effects resulting from blasting construction and to propose a plan that can decrease environmental pollution. The blasting construction area is a factory site which is about one and half million square meter and sewage disposal plant is about ninety thousand square meter. Both were selected as the areas for the tests to be conducted in determination test. The test to determine the level of noise, vibration, and total suspended particle was conducted thirty times around the blasting construction area by comparing measurement results and numerical analysis. However, as the test was not conducted in the laboratory but in the actual blasting construction area, it was not possible to do the test with the same exact conditions each true. Therefore, the test was not ideal as conditions could change from test to test. For the most part, the level of noise was below the standard level of 70dB. Every vibration test was under the standard limitation. For example, a house, 200m away was tested for noise and vibration and the level was found to be under the 0.2 cm/sec which is the standard for specialty designed cultural sites., i.e very low level. Also a buried oil pipeline that was 30m away also marked under 2.0cm/sec which is the norm for an industrial area. However, if there were an oil pipeline under the house, the amount of charging gunpowder per hole should be decreased compared to the amount used in the test. The test result for suspended particles under the standard limitation which is 24hour average 300$\mu\textrm{g}$/㎥ at a distance from blasting wavelength, but at detonator, total suspended particle from the blast origin exceeded the standard limitation. If explosion occurs when it detonates in the hole, most of the energy would be absorbed in the crushing of rocks, but some remaining energy would make noises and vibration inevitable. So the important thing is how to minimize the environmental pollution from the blasting. There should be regulations in order that the standard limitation is not exceeded, and to decrease the environmental pollution from the blasting.