• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.96-96
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• 2012

복합분자펌프는 기존의 터보분자펌프 turbine blade에 spiral grooved를 추가하여 초고진공(10-8Pa)에서 저진공(330Pa)까지 넓은 압력범위에서 사용할 수 있고 이 펌프를 사용함으로서 완전 oil free한 진공시스템을 만들 수 있는 특징을 가지고 있다. 특히, 회전체를 비접촉으로 지지하는 자기베어링 방식을 적용함으로써, 진동은 극히 작고 베어링수명은 길면서 중저진공에 대한 배기속도가 크고 임의의 방향으로 접속이 가능하여 반도체 및 디스플레이 제조 공정과 같은 첨단산업의 다양한 분야에 쉽게 적용되고 있으며, 그 적용 분야와 시장은 계속 성장하고 있다. 고 진공과 배기 속도의 달성을 위해서, 고속으로 이동하는 격면과 기체분자를 충돌시켜, 기체 분자를 원하는 방향으로 유도하는 작동원리를 가지고 있다. 특히 공기분자의 밀도가 매우 낮은 희박가스 상태에서 고속 회전하는 blade로 공기분자를 쳐내면서 작동됨으로써 날개의 상하 압력차에 의한 공기력보다도 날개의 고속회전이 매우 중요시되고 압력으로는 10-1 Pa 이하의 분자영역에서 그 성능을 최고로 발휘할 수 있다. 이러한 복합 펌프의 주요 장점은 다음과 같다. 1. 10-8 Pa (10-10 torr) ~ 10 Pa (1 torr) 까지 넓은 영역에서 배기가 가능하다. 2. 탄화수계의 대하여 높은 압축특성을 가지고 있고, 윤활유를 사용하지 않으므로 얻을 수 있는 진공상태가 고청정하다(oil free). 3. 정밀 5축제어 자기베어링으로 완전히 부상하여 회전함으로서 마모가 없고 진동이 최소화하였을 뿐 만 아니라, 또한 운전음도 거의 없다. 4. 설치조건에 제한이 없고 고장이 거의 없다. 특히 복합분자펌프는 탄화수소화합물이 없는 진공을 생성시키면서 구성요소가 간단한 반면 폭넓은 진공대역을 충족하기 때문에 산업계와 연구계의 주요 첨단 분야에서 광범위하게 사용되고 있으며, 최근 반도체 및 디스플레이, 바이오엔지니어링 등의 발전으로 적용분야가 넓어지고 있다.

• Journal of environmental and Sanitary engineering
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• v.16 no.4
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• pp.62-68
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• 2001

The advantages of hydrogen peroxide dissolution method were no discharge of noxious matter when dissolution of iron wire which used as the center supporter, reactions occur in room temperature and easy to recover dissolved iron. This study was aimed at gathering the basic data of iron wire dissolution- recovery process and proposes the reaction condition of iron wire dissolution- recovery process rind the factors influencing those reactions. The results were as follows : 1 . Hydrogen peroxide dissolution method used hydrochloric acid as the catalyst. 1. In the dissolution of iron wire(1.668 g), the condition of reaction was E1702(30 ml), HCI(20 ml) and $H_2O$(200 ml) ; time of the reaction was 18 min. P.W.(Piece weight) was 7.75 mg, and C.R. was $2.34{\;}{\Omega}$ 2. In the dissolution of iron wire(1.529 g), the condition of reaction was H7O2(30 ml), HCI(20 ml) and $H_2O$(200 ml), time of the reaction was 21 min., P.W.(Piece weight) was 7.73 mg, and C.R. was $2.35{\;}{\Omega}$. Hydrogen peroxide dissolution method used sulfuric acid as the catalyst. 1. In the dissolution of iron wire(0.834 g), the condition of reaction was $H_2O$(65 ml), $H_2SO_4$(5 ml) and 1702(5 ml) ; time of the reaction was 5 min.30 sec, P.W.(Piece weight) was 7.74 mg, and C.R. was $2.33{\;}{\Omega}$ 2. In the dissolution of iron wire(1.112 g), the condition of reaction was $H_2O$(65 ml), $H_2SO_4$(5 ml) and $H_2O_2$(5 ml) ; time of the reaction was 4 min.30 sec, P.W.(Piece weight) was 7.75 mg, and C.R. was $2.33{\;}{\Omega}$. Hydrogen peroxide dissolution method used hydrochloric acid and sulfuric acid as the catalyst confirmed a clean technology, because there were not occurred a pollutant discharged in the existing method.

• Journal of environmental and Sanitary engineering
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• v.18 no.2
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• pp.1-8
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• 2003

The advantages of hydrogen peroxide dissolution method were no discharge of noxious matter when dissolution of molybdenum wire which used as the center supporter, reactions occur in room temperature. The results were as follows : 1. In the FL/10-A type: Dissolution-reaction Time was 50Min., C.R.(Coil resistance) was $9.27{\Omega}(St.{\;}:{\;}9.2{\pm}0.22{\Omega})$, P.W.(Piece weight) was $10.59mg(St.{\;}:{\;}10.5{\pm}0.26mg)$. In the FL/15-D type: Dissolution-reaction Time was 55Min., C.R. was $6.39{\Omega}(St.{\;}:{\;}6.38{\pm}0.02{\Omega})$, P.W. was $16.7mg(St.{\;}:{\;}16.5{\pm}0.3mg)$. In the FL/20-H type: Dissolution-reaction Time was 45Min., C.R. was $4.7{\Omega}(St.{\;}:{\;}4.6{\pm}0.3{\Omega})$, P.W. was $20.8mg(St.{\;}:{\;}20{\pm}1.5mg)$. In the FL/20-C type: Dissolution-reaction Time was 60Min., C.R. was $4.5{\Omega}(St.{\;}:{\;}4.6{\pm}0.3{\Omega})$, P.W. was $19.8mg(St.{\;}:{\;}19{\pm}1.0mg)$. 2. In the GLS-230/40-B type: Dissolutiona-reaction Time was 45Min., C.R. was $105.1{\Omega}(St.{\;}:{\;}104{\pm}2.6{\Omega})$, P.W was $6.37mg(St.{\;}:{\;}6.3{\pm}0.16mg)$. In the GLS-230/60-F type: Dissolution- reaction Time was 45Min., C.R. was $65.92{\Omega}(St.{\;}:{\;}65{\pm}1.62{\Omega})$, P.W. was $11.91mg(St.{\;}:{\;}11.8{\pm}0.29mg)$.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.421-429
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• 2018

We performed process and CFD simulations of a 100 kW fuel cell system. By process simulation, we derived the input flow rate of each unit process and the recycle diesel flow rate. Through CFD simulation considering the recycle diesel flow, more efficient operational condition was found. Using 6 desulfurize reactors, a TSA process for a 100 kW fuel cell system was successfully constructed. Heat interference between reactors was found to be negligible. These results will contribute to increasing the efficiency of fuel cell system and the developed desulfurizing module design will contribute to the clean petrochemical technology as well as fuel cell systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1229-1235
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• 2014

At the LPG vehicle air intake system, most of dust particles in the air cleaner are removed. However very small particles are not removed and accumulated. The accumulation of carbon in air intake system is going to affect the idle speed control and sensor signal. It also causes engine chattering and transmission troubles of automatic transmission. This is study about cleaning up intake system using cleaning chemical. We can clean up the intake system by spraying cleaning liquid onto intake device when the engine is idling after intake hose is removed from warmed up vehicle. We can obtain the following experimental results by cleaning up ISC, surge tank, intake manifold, intake valves and combustion chamber. According to this results, the stroll valve works correctly and power rate of engine is up to the standard, it is smoothy to control the idling speed when a vehicle pulls up. After cleaning up CO grow down about 0.15%, HC does about 20~100 ppm.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.556-562
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• 2005

This study was performed to evaluate effects of pH and heavy metals on soil pollution in 167 sites of Gangwon-do. The overall pH range of soils was 4.3~8.4 The average soil pollution of Cd was 0.089 mg/kg (0.000~3.493 mg/kg), Cu 3.093 mg/kg (0.078~60.263 mg/kg), Pb 4.74 mg/kg (0.01~38.08 mg/kg), Hg 0.054 mg/kg (0.002~1.050 mg/kg), and As 0.971 mg/kg (0.031~77.051 mg/kg), but $Cr^{6+}$ was not detected in these soils. The average concentration of heavy metals in these soils was acceptable under the preliminary standard of soil preservation acts in Korea.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.205-212
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• 2004

In this paper the design of a 1-[KVA] fuel cell powered line-interactive UPS system employing modular (fuel cell & DC/DC converter) blocks is proposed. The proposed system employs the two fuel cell modules along with suitable DC/DC converters and these modules share the DC-Link of the DC/AC inverter. A supercapacitor module is also employed to compensate for the instantaneous power fluctuations and to overcome the slow dynamics of the fuel processor. The energy stored in the supercapacitor can also be utilized to handle the overload conditions for a short time period. Due to the absence of batteries, the system satisfies the demand for an environmentally friendly and dean source of the energy. A complete design example illustrating the amount of hydrogen storage required for 1hr power outage, and sizing of supercacpacitor for transient load demand is presented for a 1-[KVA] UPS.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.27-27
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• 2010

최근에 고유가와 지구온난화로 인하여 에너지가 향후 인류의 50년을 좌우할 가장 큰 문제로 대두되고 있어서 지구의 모든 에너지의 근원인 태양광을 이용하는 태양광 발전은 무한한 청정 에너지로 각광받고 있다. 빛을 흡수하여 전기에너지로 변환하는 태양전지는 풍력, 수소연료전지, 조력, 바이오에탄올 등의 신재생에너지 기술 중에서 상품성은 가장 뛰어나지만 발전단가가 가장 높은 것이 단점이다. 태양광 발전단가를 줄여서 기존의 화석에너지를 이용한 발전단가와 견줄 수 있는 그리드 패러티(grid parity)를 달성하려면 태양전지 모듈의 고효율화와 동시에 저가화가 반드시 이루어져야 한다. 현재 태양광 모듈 시장의 90%는 효율이 12-16% 정도로 높은 단결정(single crystalline or monocrystalline) 실리콘이나 다결정(polycrystalline or multicrystalline) 실리콘 등의 벌크(bulk)형 결정질 실리콘 모듈이 차지하고 있으나 원재료인 실리콘 웨이퍼의 제조단가의 50%를 차지하고 있어서 저가화가 어렵다. 반면, 원료가스를 분해하여 대면적 기판에 증착하는 박막(thin-film) 실리콘 태양전지의 경우는 차세대 태양전지로 각광받고 있다. 박막 실리콘 모듈은 매우 적은 실리콘 원재료를 소비한다. 단결정이나 다결정 실리콘 웨이퍼의 두께가 $180-250\;{\mu}m$ 정도인 것에 비해서 박막 실리콘의 두께는 $0.3-3\;{\mu}m$ 수준이다. 더불어, 유리, 플라스틱 등의 저가 기판에 저온 대면적 증착이 가능하여 저가양산화에 유리하다. 박막 실리콘 모듈은 벌크형 실리콘 모듈(-0.5%/K) 대비 낮은 온도계수[비정질 실리콘(amorphous silicon; a-Si:H)의 경우 -0.2%/K]와 빛의 세기가 약한 산란광에서도 동작하여 평균발전시간이 증가하므로 외부환경에서 우수한 발전성능을 보이고 있다. 태양전지 모듈은 상온에서의 안정화 효율을 기준으로 가격이 책정되어($/$W_p$) 판매되기 때문에 벌크형 실리콘 모듈에 비해서 박막 실리콘 모듈은 가격대 성능비가 우수하다. 따라서 박막 실리콘 모듈은 벌크형 결정 실리콘 모듈의 대안으로 떠오르고 있으며, 레이저 기술을 이용하여 수려한 투광형 건물일체형(building integrated photovoltaic; BIPV) 모듈을 제작할 수 있는 장점도 있다. 이러한 장점에도 불구하고 기존의 양산화된 단일접합 비정질 실리콘 태양광 모듈은 효율이 6-7%로 낮아서 설치면적 및 설치 모듈의 증가가 성장의 걸림돌이 되고 있다. 박막 실리콘 태양전지의 고효율화를 도모하기 위해서 적층형 탄뎀셀로 양산 트렌드가 변화하고 있다. 이에 적층형 박막 실리콘 태양전지 효율의 한계 및 돌파구에 대해서 논의한다.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.11-18
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• 2023

This study explained the need for ammonia fuel and the value chain as a hydrogen carrier. The basic concept of ammonia combustion characteristics and the development of flame stability and low NOx combustion technology were introduced. In addition, through the trend of ammonia combustion technology, the characteristics of ammonia combustion technology in the power generation and industrial sectors were examined, and the author's opinions were included. Through this paper, the author intends to give some overview of basic knowledge about ammonia fuel and its future development direction and meaning.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.28-46
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• 2001

Natural gas is a mixture of hydrocarbon gases and impurities such as nitrogen, hydrogen sulfide, and carbon dioxide and a clean energy producing no pollution materials for combustion. Currently, the demand of the natural gas is rapidly increasing due to worldwide environmental problems. According to Hubbert's study in the past, the natural gas was predicted as rapidly depleted resources, and then the results led to high gas price and limitation of usage during 1980s. Afterward, the study of natural gas resources based on geology identified the additional natural gas resources that were not considered in Hubbert's study. They are unconventional gas, additional resources in the existed reservoirs, and natural gas in deep subsurface areas. Such additional resouces made the future of natural gas bright and pormised low and stable gas price in the future. Deep natural gas is defined as the gas existing at or below 15,000ft$(4,752{\cal}m)$ in depth from the surface. According to the study from the U.S. Geological Survey(USGS) in 1995, 1,412 TCF of technically recoverable natural gas was remained to be discovered or developed in the onshore of United States. A significant part of that resource base, 114 TCF, exists at deep sedimentary basins, and it shows wide distribution with various geological environments. In 1995, the deep gas contributed to $6.7\% of total supply amount of natural gas in the United States and is expected to be $18.7\% by 201.5. However, the development of the deep gas is a high risky business due to expensive investment and high portion of dry holes, although it is developed. Thus, for developing the deep gas economically, it is necessary to overcome many technical challenges. In this paper, for increasing success rate of the deep gas, 1) geologic and compositional characteristics, and production cost have been analyzed according to depth, 2) technical problems related to deep gas production have been summarized, and 3) finally future study areas for increasing application of the deep gas have been suggested. For reference, this paper was written based on the study results from USGS and Gas Research Institute(GRI), for the United States is doing the most active R&D in the deep gas area, and thus, has many reliable data.