• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.69-72
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• 2003

Volatile organic compounds (VOC) cause air pollution problem and deterioration of atmosphere of petrochemical and fine chemical plants. Hybrid process of membrane and cold-condensation were developed and it effectively removed and recycled the VOC. Operation parameters of the process were optimized to attain hish removal and recycle of VOC. Composite membranes for organic vapor separation were developed in this work by PDMS coating and plasma polymerization on polypropylene and polysulfone support membranes. PDMS and various silicone monomers were tested for several organic vapors such as benzene, toluene, TCE, and HCFC, which are produced in petrochemical and fine chemical industry and causes air pollution problems if are released to atmosphere. Composite membranes prepared in this work showed appreciable performance in terms of organic vapor removal and reuse. Performance variation of the membranes was correlated with their surface characteristics.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.324-329
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• 2003

Asynchronus high speed turbo blower of 100HP class with gas bearing supports is developed. The high speed motor is cooled by air and it's RPM is controlled by high frequency inverter to adjust inlet flow rate. Product family is ranged from 50 to 200HP and covered by three frames. Highly efficient impeller is designed and proved by performance test on system. Overall measured system efficiency is 82% including motor and inverter. The motor efficiency is about 95%. It is designed to guarantee to operate at ambient temperature of 35 Deg.C and max 45 DegC. Gas bearing with high load capacity is developed to support heavy rotor on low rotational speed.

• 한국군사과학기술학회지
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• 제13권5호
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• pp.785-792
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• 2010

This paper on the Research of Naval Electronic Warfare System HILS(Hardware In the Loop System) describes the EW engagement HILS construction method for evaluation of the operational concept analysis on active RF Decoy in staying in the air and the deceit ability to anti-ship missile seeker. We obtain the EW M&S technology of EW engagement HILS and EW efficiency analysis from this project. This Naval Electronic Warfare System HILS technology will support Active Decoy Development Project and any other HILS of EW weapon in KOREA ARMY/NAVY/AIR FORCE.

• 한국IT서비스학회지
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• 제18권1호
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• pp.173-186
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• 2019

Recently, as the amount of fine dust has risen rapidly, our interest is increasing day by day. It is virtually impossible to remove fine dust. However, it is best to predict the concentration of fine dust and minimize exposure to it. In this study, we developed a mathematical model that can predict the concentration of fine dust using various information related to the weather and air quality, which is provided in real time in 'Air Korea (http://www.airkorea.or.kr/)' and 'Weather Data Open Portal (https://data.kma.go.kr/).' In the mathematical model, various domestic seasonal variables and atmospheric state variables are extracted by multiple regression analysis. The parameters that have significant influence on the fine dust concentration are extracted, and using ANN (Artificial Neural Network) and SVM (Support Vector Machine), which are machine learning techniques, we proposed a prediction model. The proposed model can verify its effectiveness by using past dust and weather big data.

• 대한화학회지
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• 제68권2호
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• pp.87-92
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• 2024

The commercialization of rechargeable metal-air batteries is extremely desirable but designing stable oxygen reduction reaction (ORR) catalysts with non-noble metal still has faced challenges to replace platinum-based catalysts. The nonnoble metal catalysts for ORR were prepared to improve the catalytic performance and stability by the thermal decomposition of ZIF-8 with optimum cobalt loading. The porous carbon was obtained by the calcination of ZIF-8 and different loading amounts of Co nanoparticles were anchored onto porous carbon forming a Co/PC catalyst. Co/PC composite shows a significant increase in the ORR value of current and stability (500 h) due to the good electronic conductive PCN support and optimum cobalt metal loading. The significantly improved catalytic performance is ascribed to the chemical structure, synergistic effects, porous carbon networks, and rich active sites. This method develops a new pathway for a highly active and advantageous catalyst for electrochemical devices.

• The Korean Journal of Physiology and Pharmacology
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• 제25권4호
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• pp.281-296
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• 2021

The beneficial effects of hypoxic preconditioning are abolished in the diabetes. The present study was designed to investigate the protective effects and mechanisms of repeated episodes of whole body hypoxic preconditioning (WBHP) in db/db mice. The protective effects of preconditioning were explored on diabetes-induced vascular dysfunction, cognitive impairment and ischemia-reperfusion (IR)-induced increase in myocardial injury. Sixteen-week old db/db (diabetic) and C57BL/6 (non-diabetic) mice were employed. There was a significant impairment in cognitive function (Morris Water Maze test), endothelial function (acetylcholine-induced relaxation in aortic rings) and a significant increase in IR-induced heart injury (Langendorff apparatus) in db/db mice. WBHP stimulus was given by exposing mice to four alternate cycles of low (8%) and normal air O₂ for 10 min each. A single episode of WBHP failed to produce protection; however, two and three episodes of WBHP significantly produced beneficial effects on the heart, brain and blood vessels. There was a significant increase in the levels of brain-derived neurotrophic factor (BDNF) and nitric oxide (NO) in response to 3 episodes of WBHP. Moreover, pretreatment with the BDNF receptor, TrkB antagonist (ANA-12) and NO synthase inhibitor (L-NAME) attenuated the protective effects imparted by three episodes of WBHP. These pharmacological agents abolished WBHP-induced restoration of p-GSK-3β/GSK-3β ratio and Nrf2 levels in IR-subjected hearts. It is concluded that repeated episodes of WHBP attenuate cognitive impairment, vascular dysfunction and enhancement in IR-induced myocardial injury in diabetic mice be due to increase in NO and BDNF levels that may eventually activate GSK-3β and Nrf2 signaling pathway to confer protection.

• 한국대기환경학회지
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• 제28권3호
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• pp.348-356
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• 2012

It is very important to investigate air pollutants and emissions emitted from open burning in order to control nonpoint sources effectively. In this study, we utilized incineration simulator proposed by U.S. EPA and investigated concentrations of TSP, PM10, PM2.5 from woods and household wastes burning to calculate emission factors and build emission inventories. The results of experiment with 15 kg of woods and 3 kg of household wastes using the incineration simulator were as follows: in case of woods burning, TSP concentration was $66.4mg/m^3$, PM10 concentration was $28.4mg/m^3$, PM2.5 concentration was $17.9mg/m^3$, respectively; in case of household wastes burning, TSP concentration was $118.4mg/m^3$, PM10 concentration was $66.8mg/m^3$, PM2.5 concentration was $55.2mg/m^3$, respectively. Concentrations from household burning, as stated above, were higher than those from woods burning. Emission factors (EFs) for woods and household wastes burning were calculated as 2.45 and 6.75 g/kg for TSP, 0.86 and 5.45 g/kg for PM10, 0.78 and 4.81 g/kg for PM2.5, respectively. EFs of TSP, PM10, PM2.5 calculated from household wastes burning were higher than those of woods burning. When we added PM emissions from woods burning and household wastes burning to Korean National Emission Inventory named as Clean Air Policy Support System (CAPSS), CAPSS annual emissions of TSP, PM10, PM2.5 were increased by 0.08~0.26% (An increase rate for TSP, PM10, PM2.5 were 0.08~0.10%, 0.16~0.20% and 0.18~0.26%, respectively). Note that we assumed that the 1% of household wastes is emitted by open burning.

• 자원ㆍ환경경제연구
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• 제29권2호
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• pp.113-144
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• 2020

다양한 대기질 관측 자료는 우리나라의 대기 오염이 지속적으로 개선되고 있음을 보여 준다. 하지만 일반 시민들은 최근 대기 오염 상태가 심각하며, 이로 인한 경제적 부담이 증가하였다고 인식한다. 본 연구는 이러한 인지와 관측된 자료의 차이 그리고 의료 비용 및 소비 지출에 대한 경제학적 쟁점을 세 가지로 분석하였다. 첫째, 검색량 분석과 시군구 단위 대기 오염 물질 농도 변화의 비교 분석을 통해 인지와 관측된 자료의 불일치를 확인하였다. 둘째, 의료경제모형을 이용하여 대기 오염과 의료비 지출의 이론 모형을 도출하고, 계량경제모형을 통해 대기 오염의 개선에 따른 의료 비용 감소를 실증하였다. 셋째, 소비 지출 분석을 통해 우리나라의 대기 오염에 의한 경제적 부담 증가는 소비 지출 항목에 의존하고 있음을 확인하였다. 본 연구의 결과는 우리나라 대기 오염의 사회경제적 영향을 분석 시, 분석항목에 따른 과대추정의 가능성과 대기 오염의 개선과 관련한 역해석의 문제가 있을 수 있음을 보여준다. 또한 본 연구의 결과는 대기질 관리의 보다 엄격한 기준 적용의 필요성, 방어적 소비재에 대한 사회취약층에 대한 고려 그리고 대기 오염 관련 정보의 접근성 향상 및 신뢰성 회복이 필요하다는 정책적 함의를 가진다.

• 한국지반공학회논문집
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• 제26권2호
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• pp.23-32
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• 2010

본 연구는 특별히 물과 관련된 실트질 계열의 경량기포혼합토(기포슬러리밀도 10kN/$m^3$ 대상)의 특성변화를 알아보기 위해 수행되었다. 일축압축강도, 투수계수, 모관상승고 등에 대한 연구가 이루어졌으며, 이들 연구를 뒷받침할 수 있는 경량기포혼합토의 미세구조에 대한 연구도 아울러 진행되었다. 사진을 통한 미세 구조 분석 결과 경량기포혼합토 내의 기포는 다양한 크기로 존재하며, 위치별 기포의 분포는 거의 일정한 것으로 밝혀졌다. 또한 기포 안에 아주 많은 미세한 공극들이 존재하여 물에 의해 경량기포혼합토가 포화상태에 가까이 도달될 수 있음이 밝혀졌다. 이미지를 이용한 간극률 산정도 같이 이루어졌다. 일축압축강도 시험 결과, 물에 의한 극한강도 값의 변화는 없으나 응력-변형거동에는 영향을 주는 것으로 나타났다. 경량기포혼합토의 투수계수는 평균 $4.857{\times}10^{-6}cm/sec$로 점토보다는 약간 큰 값을 갖는 것으로 나타났다. 경량기포혼합토의 모관상승은 시험초기부터 100분 이내에는 가파르게 진행되고, 그 이후 경과시간에 따라 상승속도가 점진적으로 완만하게 진행됨을 알 수 있다. 모관상승은 곧 재료의 단위중량 증가를 유발하므로 경량기포혼합토의 설계와 유지관리 시 각별한 주의가 요구된다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권1호
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• pp.30-37
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• 2005

We present an air bridge type electrode system with tunable electrode distance for detecting electroactive biomolecules. It is known that the narrower gap between electrode fingers, the higher sensitivity in IDA (interdigitated array) electrode. In previous researches on IDA electrode, narrower patterning required much precise and expensive equipment as the gap goes down to nanometer scale. In this paper, an improved method is suggested to replace nano gap pattering with downsizing electrode distance and showed that the patterning can be replaced by thickness control using metal deposition methods, such as electroplating or metal sputtering. The air bridge type electrode was completed by the following procedures: gold patterning for lower electrode, copper electroplating, gold deposition for upper electrode, photoresist patterning for gold film support, and copper etching for space formation. The thickness of copper electroplating is the distance between upper and lower electrodes. Because the growth rate of electroplating is $0.5{\mu}m\;min^{-1}$, the distance is tunable up to hundreds of nanometers. Completed electrodes on the same wafer had $5{\mu}m$ electrode distance. The gaps between fingers are 10, 20, 30, and $40{\mu}m$ and the widths of fingers are 10, 20, 30, 40, and $50{\mu}m$. The air bridge type electrode system showed better sensitivity than planar electrode.