• 멤브레인
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• 제29권4호
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• pp.216-222
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• 2019

본 연구에서는 역세척이 가능한 평막과 MBR 하부에서 공급되는 공기 및 자연적으로 순환되는 구형 입자를 이용하여 투과 실험하였다. 활성슬러지 수용액은 MLSS 8,000 mg/L로 유지하였으며 여과/이완(FR), 이완시 역세척(FR/BW), 사인파형 연속투과 운전(SFCO) 및 사인파형 연속투과 운전 시 역세척(SFCO/BW) 방식에 따른 막간차압(TMP)을 측정하였다. 역세척 유량을 47에서 $14L/m^2{\cdot}hr$로 감소시키면, TMP가 증가하였으며 SFCO보다는 FR 방식의 TMP가 크게 증가하였다. 또한 역세척 방식이 구형입자를 이용한 세척방식보다 TMP를 더 감소시켰으며, 구형입자와 역세척 방식을 동시에 사용하면 각각의 방법보다 더 효과적임을 확인할 수 있었다.

• 상하수도학회지
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• 제27권4호
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• pp.439-444
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• 2013

Excessive phosphorus in aquatic systems causes algal bloom resulting in eutrophication, DO depletion, decline in recreational value of water and foul tastes. To treat wastewater containing phosphorus including effluent of wastewater treatment plant, the continuous experiments were performed by using electrochemical way. The spherical ZVI and silica sand which act as physical filter are packed at appropriate volume ratio of 1:2. Electric potential is applied externally which can be changed as per the operational requirement. The results indicate that optimum hydraulic retention time of 36 minutes (10 mL/min at 1 L reactor) was required to meet the effluent standards. Lower concentrations of phosphorus (<10 mg/L as phosphate) were removed by precipitation by contact with iron. Thus, additional electric potential was not required. In order to remove high concentration phosphorus around 150 mg/L as phosphate, external electric potential of 600 V was applied to the reactor.

• 폴리머
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• 제26권4호
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• pp.516-522
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• 2002

4급 암모늄기를 관능기로 갖는 아민화 아크릴계 이온교환섬유를 이용하여 연속식 흡착공정 중 linear alkylbenzene sulfonate(LAS)의 흡착특성을 확인하였다. 아민화 아크릴계 이온교환섬유의 LAS흡착성능은 온도가 증가함에 따라 증가하였으며 $40^{\circ}C$에서 최적 흡착성능을 나타내었다. 또한 컬럼 베드 충진비(L/D)의 변화에 따른 LAS 이온의 흡착능은 L/D>2에서 최대 흡착능을 나타내었다. pH 변화에 따른 LAS이온 흡착능은 pH가 증가함에 따라 증가하는 경향을 나타내었고, pH 7에서 최대 흡착능을 나타내었다. 유속변화에 따른 LAS 흡착능은 유속이 증가할수록 낮아졌으며 농도가 높을수록 떨어졌다.

• 한국컴퓨터그래픽스학회논문지
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• 제17권3호
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• pp.33-42
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• 2011

본 논문에서는 B-spline 곡선의 낫 제거 (knot removal)를 위한 새로운 기법을 제안한다. 제안된 기법은 낫 제거 전후, 두 곡선의 형상의 차이를 측정하기 위해 하우스도르프 거리 (Hausdorff distance)를 이용한다. 먼저 Eck와 Hadenfeld의 연속 $L_{\infty}$ 근사법[1]을 이용하여 낫이 제거된 곡선을 생성한다. 수치적 최적화 (numerical optimization) 기법을 통해 생성된 곡선의 제어점 위치를 조정하여, 낫 제거 전 곡선과의 하우스도르프 거리가 최소화 되도록 한다. 본 논문에서는 다양한 형태와 차수의 곡선들(space curves)에 대한 낫 제거 실험을 통해 제안된 기법의 효율성과 우수성을 입증한다.

• 환경위생공학
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• 제14권3호
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• pp.123-129
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• 1999

The utilization methods of algae biomass have been studied constantly in whole world. These are $\circled1$the wastewater treatment if waste stabilization pond and oxidation ditch etc. and $\circled2$the biosorption of heavy metals and recovery of strategic' precious metals and $\circled3$the single-celled protein production and the production of chemicals like coloring agent and $\circled4$the production of electric energy through methane gasification. The culture system also has been developed constantly in relation with such utilization method developments. In the result of experimental operation under continuous and cyclic irradiation of light, using high rate algae biomass culture pond(HRABCP), which had been made so as to be an association system with the various items which had been managed to have high efficiency for algae culture, the algae production of the 12 hours-irradiance pond was 41.48 Chlorophyll-a ${\mu}g/L$ only in spite of having the more chance of $CO_2$ synthesis to algae cell than the 24 hours-irradiance pond. This means that the energy supply required for dark-reaction of photosynthesis is very important like this. The difference of algae production between continuous and cyclc irradiation explains that the dark-reaction of photosynthesis acts on algae production as the biggest primary factor. The continuous irradiance on HRABCP made the good algae-production($1403.97{\;}{\mu}g$ Chlorophyll-a/mg) and the good oxygen-production(5.8 mg $O_2/L$) and the good solid-liquid seperation. especially, DO concentration through the oxygen-production was enough to fishes' survival.

• 한국지반환경공학회 논문집
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• 제16권3호
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• pp.35-39
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• 2015

Dowex 21K XLT 수지를 이용하여 산업폐수 내에 존재하는 금과 납-시안 착화합물에 대한 연속흡착 및 회수 특성을 조사하였다. 충전층에 충진된 Dowex 21K XLT 수지는 0.5mL/min의 유입유속에서 금-시안 착화합물을 520 bed volume까지 95% 이상 연속적으로 제거할 수 있지만, 납-시안 착화합물은 전혀 제거할 수 없었다. Dowex 21K XLT 수지에 흡착된 금-시안 착화합물은 HCl과 Acetone을 7:3의 비율로 섞은 혼합액을 탈착제로 이용하였을 때, 8 bed volume 내에서 96% 탈착되어졌다. 또한 두 번 재사용된 Dowex 21K XLT 수지의 금-시안 착화합물에 대한 bed volume이 490을 유지하여 향후 금 이온을 포함하고 있는 산업폐수 처리공정에 충분히 적용될 수 있을 것으로 판단된다.

• KSBB Journal
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• 제17권1호
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• pp.26-32
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• 2002

세포의 다당류 xanthan을 생산하기 위하여 호기성 박테리아 X. campestris를 9 L 삼상유동층 생물반응기에서 연속적으로 배양하였다. 고점도 배양액에서 공기 기포를 분쇄하기 위하여 직경 8 mm 유리 유동입자를 사용하였다. 반응기 희석률을 증가시킴에 따라 세포 단위질량 당 xanthan 생성속도 및 생성된 xanthan의 분자량은 증가하였다. 산소공급제한이 발생하지 않을 경우 연속발효에서의 xanthan 비생성속도는 회분식 발효에서 제안된 상관식의 예측결과 보다 상당히 높은 값을 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.244-249
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• 1998

In this paper, the hybrid state space self-tuning control technique Is studied within the framework of fuzzy systems and dual-rate sampling control theory. We show that fuzzy modeling techniques can be used to formulate chaotic dynamical systems. Then, we develop the hybrid state space self-tuning fuzzy control techniques with dual-rate sampling for digital control of chaotic systems. An equivalent fast-rate discrete-time state-space model of the continuous-time system is constructed by using fuzzy inference systems. To obtain the continuous-time optimal state feedback gains, the constructed discrete-time fuzzy system is converted into a continuous-time system. The developed optimal continuous-time control law is then convened into an equivalent slow-rate digital control law using the proposed digital redesign method. The proposed technique enables us to systematically and effective]y carry out framework for modeling and control of chaotic systems. The proposed method has been successfully applied for controlling the chaotic trajectories of Chua's circuit.

• Steel and Composite Structures
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• 제1권2호
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• pp.213-230
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• 2001

This paper presents a simplified approach for the design of semi-continuous composite beams in braced frames, where specific attention is given to the effect of joint rotational stiffness. A simple composite beam model is proposed incorporating the effects of semi-rigid end connections and the nonprismatic properties of a 'cracked' steel-concrete beam. This beam model is extended to a sub-frame in which the restraining effects from the adjoining members are considered. Parametric studies are performed on several sub-frame models and the results are used to show that it is possible to correlate the amount of moment redistribution of semi-continuous beam within the sub-frame using an equivalent stiffness of the connection. Deflection equations are derived for semi-continuous composite beams subjected to various loading and parametric studies on beam vibrations are conducted. The proposed method may be applied using a simple computer or spreadsheet program.

• 호남수학학술지
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• 제40권1호
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• pp.27-46
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• 2018

In this paper, (E, L)-preproximity and uniformity spaces in matriod theory as a generalized to a classical proximity and Uniformity spaces introduced by Csaszar [1] is introduced. Recently, Shi [17]-[18] introduced a new approach to the fuzzification of matroids.Here introduce (E, L)-preproximity and uniformity spaces, Uniformity and strong uniformity on (E, L)-fuzzifying matroid space, Not only study the properties of this new notions, but it has been generated (E, L)-fuzzifying matroid Space from (E, L)-preproximity and uniformity spaces. Next to introduced (E, L)-preproximity continuous in (E, L)-fuzzifying matroid space and used it in more properties. Finally we solve combinatorial optimizations problem via (E, L)-fuzzifying matroid space.