• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.455-456
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• 2000

Characteristics of $CO_2$ fixation by Chlorella sp. HA-1 were studied in a semi-continuous mode in a series operation. A high $CO_2$ fixation rate for a long time was obtained, when the method of semi-continuous mode was employed, in which the controlling parameter was the dilution ratio. A constant $CO_2$ fixation rate was maintained even when the dilution ratio was increased with the increment of 0.1 at the initial value of 0.5. The method of series operation was used to improve the efficiency of $CO_2$ fixation. The total amount of $CO_2$ fixation was proportion to the number of reactor in series operation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.400-405
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• 2005

The vertical slope of railway track is the differences of attitude for the horizontal distances between two positions of railway. It is better to be small vertical slope for the comfortable of passengers and the operation of railway system. However, the variable vertical slope is required that the simple vertical slope causes the huge quantities of embankment and cutting, the continuous welded rail tunnels, the continuous welded rail bridges, etc,. This research is for the relation between the vertical slopes and the trainset performances. This research shows that the effective vertical slopes for the operation of railway. The velocity of car and operation time and the consumed energy was considered for each vertical slope and type of car power system. The result of suitable vertical slope from this research is to be used for the design of railway plan.

• 한국환경과학회지
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• 제32권5호
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• pp.385-394
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• 2023

There is a need for a method that can effectively remove wastewater containing small-sized particles such as TiO₂. In this study, we attempted to remove TiO₂ wastewater using electrocoagulation-electroflotation two-step separation. The TiO₂ wastewater was effectively removed via batch electrocoagulation-electroflotation separation. However, in the batch process, the simultaneous operation of electrocoagulation and electoflotation was challenging due to the high residual turbidity. In the continuous operation, electrocoagulation and electoflotation reactors were kept separate. The turbidity removal in continuous operation was similar to that in the batch process, nevertheless, the residual Al concentration was high, leading to the conclusion that counterterm ensures against residual Al were necessary.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.899-904
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• 2007

Improvement projects has been progressed for railway electrification and double track line in the conventional line as well as high speed line for the high speed and large transportation capability of railway. Especially, many variable operation plans are possible such as interaction between high speed line and conventional line and operation of tilting train due to the electrification of the conventional line. Railway electrification is more energy efficient and environmentally-friendly, but it has some problems such as an enormous initial construction and maintenance costs and electrical accidents. Therefore, the more intensive research will be progressed about railway electrification effectiveness for the continuous electrification project. So, we analyzed railway electrification effectiveness about the energy side using annual operation data of electric car and diesel car. The energy side was divided into energy costs and national energy consumption for analyzing electrification effectiveness about entire line and specific line. We verified advantage of energy costs and national energy consumption in this paper and this result will contribute to the progress of the continuous electrification project and the more efficient operation ways in electrification line

• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.661-666
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• 2014

Both lactic acid productivity and cell growth were linearly correlated with yeast extract supplementation in batch fermentation. During conventional continuous operation, although fresh feed was introduced into the bioreactor with a significantly low dilution rate (0.04 $h^{-1}$), the amount of yeast extract employed was not enough to maintain the growth of microorganism. However, when the fresh feed contained 100 g/l glucose and 2 g/l yeast extract during cell-recycle continuous operation at a dilution rate of 0.04 $h^{-1}$, more than 90 g/l lactic acid was continuously produced, with the average productivity of 3.72 $g/l{\cdot}h$. In this experiment, 82 g of yeast extract (77% of reduction yield) could be reduced for the production of 1 kg of lactic acid compared with batch fermentation of a similar volumetric productivity.

• 한국산학기술학회논문지
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• 제14권10호
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• pp.5304-5309
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• 2013

methylethylketone(MEK)의 광분해 특성을 연속식 단일관형태의 광촉매반응기를 이용하여 연구하였다. 연속식 광촉매반응기에 적용된 주요 반응변수는 MEK의 초기농도, 광세기, 장기운전의 영향이었다. MEK의 주입농도가 증가할수록 광분해 효율은 감소하였으며, 광분해 감소의 폭은 높은 유속에서 더욱 두드러졌다. 동일한 체류시간의 조건에서 광반응기의 직경과 UV램프의 파장이 증가할수록 MEK제거효율은 감소하였다. 연속식 광촉매반응기를 120시간 연속적으로 운전하여도 MEK 제거효율에서의 감소는 없었다.

• KSBB Journal
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• 제16권3호
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• pp.274-280
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• 2001

본 연구에서는 레트로바이러스 생산 세포인 CRIP/LacZ 세포의 배양시에 혈청의 역할을 대체 할 수 있는 여러 첨가불을 선정하고 그 농도를 정하는 실험올 수행하여, 레트로바이러 스 생산을 워한 무혈청 배지를 개발하였다. 그 결과 DMEM 을 기본배지로 하고 insulin, transfenin, BSA, EGF and linoleic acid를 포함한 무혈청 배지를 개발하였다. 이를 충전 층 연속배양기흘 이용한 레트로바이러스의 연속생산 실험에 본 결과 $6-7\times10^4 cfu/ml$서 수율을 가진 레트로바이러스를 약 8일간 생산할 수 있었다. 충전층 연속반응기에서도 T -flask와 같이 온도의 영향이 매우 중요하였고 $32^{circ}C$, 에서 가 장 높은 수율회 레트로바이러스를 생산할 수 있었다. 이는 레트로바이러스외 온도에 따흔 비활성속도가 바이러스 생산 수율에 매우 큰 영향음 마칩을 시사해 주논 결과이다. 또한 충전층 배양기에서 무혈청배지를 이용한 세포배양 시에는 무혈청배지 첨가물로 서1포 부착 물짚에 대한 연구가 필요하다고 생각된다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권9호
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• pp.545-551
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• 2004

CBTC(Communication Based Train Control) System can improve train operation efficiency by realizing moving block system which makes a continuous train interval control in accordance with the position and speed of train. Adopting radio transmission to make a continuous detection of train position and transmit the control data from the ground to a train, CBTC needs dedicated train operation and control algorithm which should be quite different from the conventional track-circuit-based train control system. This paper provides a train operation display and control algorithm for CBTC system in making train interval control, train route control and train supervision. Signalling pattern diagram is devised to analyze the train interval control mechanism of moving block system, and interlocking logic is devised to represent the train route control mechanism of moving block system. For train supervision, train occupation status on railway are displayed by using the segment which virtually divide the whole railway. The proposed method has been successfully applied to the development of CBTC system for the standardized AGT(automatic guided transit) which is under construction now in Korea, and also can be applied to any other CBTC system.

• 한국환경과학회지
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• 제19권11호
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• pp.1315-1322
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• 2010

A membrane bioreactor (MBR) was designed using polyvinylidene fluoride(PVDF)-type hollow fiber membrane modules with a treatment capacity of 10 ton/day. A pilot plant was installed in a sewage treatment plant and was operated with an intermittent aeration method which avoids any concentration gradient of suspended solids (SS) in the MBR. For continuous operation, the pilot plant was first tested with influent (mixed liquor suspended solid:MLSS of 1000-2000 mg/L) of aeration tanks in the sewage treatment plant. The MBR was pre-treated with washing water, 10% ethanol solution, 5% NaOCl solution and finally washing water, one after another. To demonstrate the effect of the MBR on sewage treatment, compared with conventional activated sludge processes, we investigated the relationships among permeate amount (LMH), change in operation conditions, influent MLSS level and sludge production. It was found that the optimum aeration rate and suction pressure were $0.3\;m^3$/min and 30~31 cmHg, respectively. Under stable conditions in aeration, suction pressure, influent flow rate and drainage, the SS removal efficiency was more than 99.99% even when the MLSS loading rate changes. Compared with conventional activated sludge processes, the MBR was more effective in cost reduction by 27% based on permeate amount and by 51.5% on sludge production.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.829-834
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• 2003

Many types of omnidirectional wheels with passive rollers have gaps between rollers. Since these gaps cause a wheel to make discontinuous contact with the ground, they lead to vertical and/or horizontal vibrations during wheel operation. In addition, the radii of passive rollers are related to the height of a bump an omnidirectional wheel can surmount. In this research a new design of the alternate wheel is proposed. Because this wheel makes continuous contact with the ground and has alternating large and small rollers around the wheel, it is termed a continuous alternate wheel (CAW). In this paper a design procedure is also presented to determine the optimum number of rollers, the radii of rollers and the inside inclination angle of an outer roller for given design specifications. The CAW based on this design is compared to the existing alternate wheels in terms of design. Finally, an actual continuous alternate wheel is constructed to verify validity of the design guidelines.