• International Journal of Aeronautical and Space Sciences
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• 제9권1호
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• pp.129-136
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• 2008

An roll-pitch-yaw integrated autopilot for missiles is designed for compensation of dynamics coupling. The proposed autopilot is based on the classical control technique. The gains of the proposed autopilot are optimized by using co-evolutionary augmented Lagrangian method(CEALM). Several cost functions are compared in order to find feasible control gains. For a case that a bank angle of missiles is unknown, multiple models are used in the autopilot optimization. In nonlinear simulations as well as linear simulations, the proposed autopilot provided good performances.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.252-255
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• 2009

The roll gap set-up in the finishing mill is one of the most important technologies in the hot plate rolling process. As the target thickness can be obtained by the correct set-up of the roll gap, improving the roll gap set-up technology is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. The objective of this study is to adjust the roll gap set-up for the thickness accuracy of plate in hot rolling process considering top-end temperature drop. Therefore this study has concentrated on determining the correct amounts of roll gap to compensate thickness variation due to top-end temperature drop. The off-line simulation of compensated roil gap significantly decreases top-end thickness variation.

• 한국환경보건학회지
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• 제28권5호
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• pp.35-41
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• 2002

This study was conducted to evaluate the effect of initial concentration on pilot-scale composting of diesel-con-laminated soil. Sandy soi] was used in this study. Target contaminant, diesel oil, was spiked. at about 10,000, 25,000, and 50,000 mg TPH/kg of dry roil. Mit ratio of soil to sludge was 1:0.5 as wet weight basis. Removal efficiencies for initial concentrations of 12,966,23,894 and 51,042 mg TPH/kg were 90, 93 and 54％, respectively, during 33 days of composting. Normal alkanes in TPH ranged from 15 to 22％ in initial soils. Volatilization of individual normal alkane in 1,999 mg n-alkanes/kgwas completed within 4 days, while n-alkane compounds of Cl1-Cl4 in 5,270 and 9,836 mg n-alkanes/kg were volatilized continuously during 33 days of composing operation. The first order degradation rate con-stants for 12,966, 23,894, and 51,042 mg TPH/kg were 0.058, 0.076, and 0.022/day, and those for 1,997 5,270, and 9,836 mg n-alkanes/kg were 0.093, 0.100, and 0.019/day, respectively. Considering TPH removal rate, $CO_2$porduction rate, and dehydrogenase activity, the concentration of 51,042 mg TPH/kg inhibited biodegradation of diesel-composting.

• International Journal of Aeronautical and Space Sciences
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• 제1권1호
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• pp.1-12
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• 2000

The wake geometries of a two-bladed rotor in axial flights using a time-marching free-wake method without a non-physical model of the far wake are calculated. The computed free-wake geometries of AH-1G model rotor in climb flight are compared with the experimental visualization results. The time-marching free-wake method can predict the behavior of the tip vortex and the wake roil-up phenomena with remarkable agreements. Tip vortices shed from the two-bladed rotor can interact with each other significantly. The interaction consists of a turn of the tip vortex from one blade rolling around the tip vortex from the other. Wake expansion of wake geometries in radial direction after the contraction is a result of adjacent tip vortices begging to pair together and spiral about each other. Detailed numerical results show regular pairing phenomenon in the climb flights, the hover at high angle of attack and slow descent flight too. On the contrary, unstable motions of wake are observed numerically in the hover at low angle of attack and fast descent flight. It is because of the inherent wake instability and blade-vortex-interaction rather then the effect of recirculation due to the experimental equipment.

• 한국미생물·생명공학회지
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• 제14권6호
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• pp.467-471
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• 1986

Fusarium moniliforme으로부터 순모세포벽 분해효소를 생산하고 분리, 정제하여 효소특성 및 protoplast 제조실험을 하였다. Ammonium nitrate를 0.2％ 첨가한 Baker's yeast 배지에서 7일간 진탕배양으로 효소를 생산한 후 Ammonium sulfate로 분획하고 Sephadex(G-100) column chromatography하여 세개의 peak를 얻었다 첫 번째 peak는 proteolytic, lytic activity 및 laminarin 분해력가를 보였으며, 두 번째 Peak는 lytic activity와 laminarin 분해력가를 동시에 가지고 있었으며, 세 번째 peak는 lytic activity만을 가지고 있었다. 분리된 세개의 peak를 혼합하였을때 개개의 peak보다 훨씬 높은 역가을 나타내어 상승효과를 보였고 또한 환원제에 의한 효소력가의 상승효과도 있었다. protoplast 수율은 99.2％정도였다

• 대한조선학회논문집
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• 제42권1호
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• pp.57-63
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• 2005

This paper introduces basic research of optimum routing assessment system as voyage support purpose which can obtain safe and efficient route. In view point of safety, the prediction of ship motion should be evaluated in the condition of rough weather This part includes general seakeeping estimation based on 3 dimensional panel method and parametric roil prediction. For increasing voyage efficiency, ETA(Estimated Time of Arrival) and fuel consumption should be calculated considering speed reduction and power increase due to wave effects based on added resistance calculation and ship performance characteristics. Basically, the weather forecast is assumed to be prepared previously to operate this system. The idea of these factors in this system will be helpful to escape from dangerous voyage situation by wave conditions and to make optimum route planning based on ETA and fuel consumption.

• 대한조선학회논문집
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• 제41권6호
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• pp.1-7
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• 2004

Recently, very large container ships are emerging as shipment of containers is expected to rapidly increase near future. A possibility of roll resonant motion in a seaway is expected to noticeably increase for large container ships of which capacity ranges 8,000 to 15,000 TEU due to relatively wide breadth and shallow draft comparing to conventional container ships. In this paper, a design and performance evaluation of a fin stabilizer for a 9,000 TEU container ship is carried out. The weak opposed control concept is adopted for the design. Time domain simulations and model tests are performed for performance evaluation. The design prediction, the model tests and the simulations show generally good agreements.

• 대한조선학회논문집
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• 제43권6호
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• pp.667-674
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• 2006

Accurate prediction of ship dynamics, particularly roll motion, is very important in ship safety. In the past, empirical or vortex based methods were commonly used for the hydrodynamic roll damping predictions but they could not be applied to practical ship roll motion cause of limitations about geometries ad design conditions. Recently RANS-based techniques are developed for the practical ship motion analysis. In this study, RANS based roil analysis about a rectangular cylinder with WAVIS developed by MOERI/KORDI are performed and compared with the experimental data and other RANS results.

• 대한조선학회논문집
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• 제44권5호
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• pp.517-525
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• 2007

This paper presents how to approximate an optimal shape of roll bending process in the fabrication of a curved shell plate. The roll bending process usually makes the cylindrical or conic shape from an initial flat plate. It means that the final shape is developable or its surface representation has zero Gaussian curvature. The fabrication shape is important in order to find process parameters of roil bending. An optimal concept is used to determine the developable fabrication shape which is in the closest proximity to the design surface or the given shell plate and is subject to developability. The results and the efficiency of this algorithm are evaluated by applying to some shell plates. Furthermore, the fabrication shape will be fundamental information for other process parameters of roll bending such as the vertical displacement of the center roller and the rolling directions.

• The Korean Journal of Ecology
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• 제25권3호
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• pp.139-144
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• 2002

군사지역은 TNT와 같은 화약물질이 중금속과 복합으로 오염되어 있다. 따라서 TNT에 대해 식물상 복원공법을 적용할 때 중금속이 식물체의 오염물 제거, 변환, 축적 능력에 영향을 줄 것으로 예상된다. 본 연구에서는 토착 야초류인 어저귀(Abutilion avicennae)를 TNT와 Cd으로 복합 오염된 배지에 서 수경재배하여 카드뮴이 식물에 의한 TNT 제거 및 변환에 미치는 영향을 조사하였다. 그 결과, 20 mgTNT/L와 1.3 mgCd/L이 복합으로 존재할 때 잎의 탄력 감소, 말림 현상, 황백화 현상, 낙엽형성, 생체량 감소 등과 같은 식물 독성효과가 상승하였다. 그러나, 어저귀는 소량의 카드뮴만을 흡수하는 종으로 배지내 카드뮴이 1.3 mg/L 존재하더라도 TNT제거, 변환, 이동 및 니트로기의 환원위치에 유의적인 영향을 받지 않는다. 따라서 카드뮴과 TNT로 복합오염된 지역에 어저귀를 식재하면 TNT를 효과적으로 제거하리라 사료된다.