• 한국토양비료학회지
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• 제29권2호
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• pp.107-112
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• 1996

토양의 규산 흡착기작을 밝히고자 continuous stirred-flow(연속진탕흘림) 법을 이용하여 시간 경과에 따른 규산 흡착량 변화에 대한 실험을 $25^{\circ}C$, pH 3수준(5, 6.5, 8)에서 실시하였다. 규산 흡착량은 실험기간내 최대 흡착량을 보이지 않고 계속 증가 하였다. 시간에 따른 규산의 흡착과정을 2단계로 구분 하였고, 1단계 반응과정은 아래의 지수함수식에서 고도의 유의성있는 상관관계를 보였다 $$R_{ad}=K_a*(Q_{OH}^S)^n$$ 여기서 $R_{ad}$는 규산흡착속도($Si\;{\mu}mal/min$), $Q_{OH}^S$는 알칼리 투여를 통하여 생성된 토양표면 음전하량, $K_a$와 n 은 상수이다. 1단계 반응과정의 n값은 1.1로 한자리 결합(monolantate ligand bonding)에 의한 흡착과정인 것으로 나타났다. 2단계 과정은 아래 식에서 고도의 유의성있는 상관관계를 보였다. $$R_{ad}=K_b*(pH)$$ 이때 $K_b$ 는 비례상수로, pH 증가에 따른 규산 흡착 속도의 증가 추세가 지수 함수적으로 감소하는 경향을 보였다.

• 한국강구조학회 논문집
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• 제17권2호통권75호
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• pp.195-206
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• 2005

6m-6m의 2경간 연속합성보에 대한 실험적 연구를 수행하였다. 유로코드에서 제시하고 있는 균열폭 제어 규정의 근거를 살펴보고 인장강화 효과를 고려한 균열상태에 따른 균열폭 계산식 유도과정을 제시하였다. 부모멘트 인장을 받는 바닥판의 거동을 초기균열, 안정화 균열로 나누어서 연속합성보의 거동을 평가하였다. 실험결과로부터 연성 기준을 만족하는 최소철근비는 현재 도로교설계기준보다 낮춰도 될 것으로 판단된다. 균열을 일으킨 연속합성보의 휨강성 평가에서는 안정화균열 이전단계까지는 비균열단면으로 보는 것이 적절하다. 인장철근의 응력과 균열폭의 관계식을 실험결과를 이용하여 제시하였다.

• Journal of Microbiology and Biotechnology
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• 제6권1호
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• pp.36-42
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• 1996

The production of sorbitol by permeabilized cells of Zymomonas mobilis immobilized in $\kappa$-carrageenan was investigated. Cetyltrimethylammoniumbromide (CTAB) permeabilized cells were treated with glutaraldehyde prior to immobilization for cross-linking of enzymes, glucose-fructose oxidoreductase (GFOR) in cells. Rigidity of the immobilized beads was increased two-fold with 90$\%$ conversion efficiency by the additions of 40$\%$ (w/v) polyols (glycerol 25 g + propylene glycol 15 g) to 60$\%$ (w/v) distilled water containing 2.5$\%$ (w/v) $\kappa$-carrageenan as a final concentration, prior to immobilization. $\kappa$-Carrageenan beads entrapping permeabilized cells were dried to improve bead rigidity and storage stability. During s6mi-batch process for 72 h with dry beads, there was an improvement of the loss of enzyme activity (less than 10$\%$). In batch process, the kinetic results of $K_m.fructose$ value for the free cells, wet beads and dry $\kappa$-carrageenan beads were 71.7, 72.4 and 116.7 g/l, respectively. Higher productivity was obtained with two-stage continuous packed bed reactors with both wet and dry $\kappa$-carrageenan beads at 25.00 and 21.15 g/l/h, respectively, when measured at second stage.

• 상하수도학회지
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• 제25권3호
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• pp.343-348
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• 2011

Since 2005, food waste has been separately collected and recycled to animal feed or aerobic compost in South Korea. However, the conventional recycling methods discharge process wastewater, which contain pollutant equivalent to more than 50% of food waste. Therefore, anaerobic digestion is considered as an alternative recycling method of food waste to reduce pollutant and recover renewable energy. Recent studies showed that hydrogen can be produced at acidogenic stage in two-stage anaerobic digestion. In this study, the authors investigated the effects of pretreatment time and pH low set value on continuous mesophilic hydrogen fermentation of food waste. Food waste was successfully converted to $H_2$ when heat-treated at $70^{\circ}C$ for 60 min, which was milder than previous studies using pH 12 for 1 day or $90^{\circ}C$. Organic acid production dropped operational pH below 5.0 and caused a metabolic shift from $H_2/butyrate$ fermentation to lactate fermentation. Therefore, alkaline addition for operational pH at or over 5.0 was necessary. At pH 5.3, the result showed that the maximum hydrogen productivity and yield of 1.32 $m^3/m^3$.d and 0.71 mol/mol $carbohydrate_{added}$. Hydrogen production from food waste would be an effective technology for resource recovery as well as waste treatment.

• 멤브레인
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• 제16권3호
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• pp.167-181
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• 2006

전기탈이온 시스템은 전기투석과 이온교환수지법의 혼합 공정으로서 외부전기장 하에서의 이온교환매개체를 통해 이온이 제거되어 고순수를 제조할 수 있도록 고안된 장치이다. 전기탈이온 장치는 이온의 제거 메커니즘과 이온교환 매개체의 전기적 재생 메커니즘으로 설명되며 이를 이용하여 희석조의 성능을 최적화하는 것이 시스템의 효과적인 사용을 위해서 필요하다. 또한 전기탈이온 장치의 다양한 분야에서의 적용을 위해서는 스택구성을 다양하게 변경하여 적용가능성을 판단하는 것이 필요하다. 이를 효과적으로 달성하기 위해서는 기존에 제시되었던 다양한 시스템 특성분석법과 이동현상 관련 수식들을 이해하여 전기탈이온 스택구성에 적용하는 것이 무엇보다 중요하다. 본 총설에서는 전기탈이온 장치의 최적화를 위해 필요한 기초 이론들과 방법들에 대해서 살펴보고 현재의 연구동향에 대해서 고찰하여 분리공정으로서의 이해를 높이고자 하였다.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1979년도 춘계학술대회
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• pp.115.2-115
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• 1979

By employing a two-stage continuous culture system, some of important physiological parameters involved in cellulase bicsynthesis have been evalua-ted with an ultimate objective of detigning an op-timally controlled tellulase process. Volumetric and specific cellulase productivities obtained were 90 IU/liter/hr and 8IU/g biomass/hr respectively. The maximum specific enzyme productivity observed was 14.8 IU/g hiomass/hr. The optimal dilution rate in the second stage which corresponded to the maximum enzyme productivity was 0.026-0.028 hr$^{-1}$ , and the specific growth rate in the second stage ihat suported maximum specific enzyme productivity was equal to orslightly less than zero. The maintenance coefficients deter-mined for oxygen and for carbon source are M$_{o}$=0.85mmmole/g biomass/hr and M$_{c}$=0.14 mmole hexose/g bio mass/hr respectively. The yield constants determined are; Y(x/o) =32.3g biomass/mole oxygen, Y (x/c) =1.1g bio-mass/g carbon or 0.44g biomass/g hexose, Y(x/n) = 19.6g biomass/g nitrogen for the enzyme produc-tion stage and 12.5g biomass/g nitrogen for the cell growth stage.e.e.

• 한국농촌건축학회논문집
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• 제13권4호
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• pp.115-124
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• 2011

This study examines the process of urban formation in the city of Yanji. The analysis is done by the change of street pattern and major facility location in a timely manner by appling space syntax method. This research categorizes the pattern of the urban growth focused on two urban forms, street and major buildings, in the city and is offered of the meaning of the first value on interpretation of the urban growth in the city of Yanji. The result of the research are as follows. First, the period of the city transformation is divided into four stage; intuitive period, grid-iron formative period, consolidation period, and urban expansion period. Second, characteristics of each stage have been analyzed. At the first stage, the city started to frame along both buildings and streets which were placed without a plan. At the second stage, the city was planned and constructed into new grid-iron pattern ignoring existing context by Jananese colony. At the consolidation period, the road system expands from the city center toward suburban. At the last expansion period, the shape of the city has complicated its shape with complex road system. This study contributes to provide a basic analysis and data to investigate how the Yanji city has evolved over period of time. But further continuous research should be done for future urban development of the Yanji city.

• 대한교통학회:학술대회논문집
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• 대한교통학회 1998년도 Proceedings The 4th International Transport Symposium
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• pp.160-167
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• 1998

Recent world-wide interest in activity-based travel behavior modeling has generated an entirely new perspective on how the profession views the travel demand process. This paper seeks to further promote the case of activity-based travel behavior models by providing some empirical evidence of relationship between travel time and activity duration decision for worker with transportation panel data. The travel time from home to work and from work to home, without activity involvement, is estimated by the Ordinary Least Squares (OLS) method. And, the travel time to and from the selected activity and the activity duration are modeled simultaneously by the Three Stage Least Squares (3SLS) method due to the endogenous relationship between travel time and activity duration. Two kinds of models, OLS and 3SLS, include selectivity bias corrections in a discrete/continuous framework, because of the inter-relationship between the choice of activity type/travel mode (discrete) and the travel time/activity duration (continuous). Estimation is undertaken using a sample of over 1300 household two-day trip diaries collected from the same travelers in the Seattle area in 1989. The behavioral consequences of these models provide interesting and provocative findings that should be of value to transportation policy formulation and analysis.

• 한국콘텐츠학회논문지
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• 제20권4호
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• pp.295-304
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• 2020

본 연구는 브랜디드콘텐츠 광고의 커뮤니케이션 기법에 관하여 연구해 본 탐색적 논문이다. 광고의 발전과정과 개인화 된 모바일 광고트랜드 현상, 브랜디드콘텐츠의 유형들을 고찰한 후, 남녀 전문가 집단 10명을 대상으로 심층면접/반구조화 면접을 진행하여 브랜디드콘텐츠의 움직임에 관하여 제작자의 입장과 소비자의 입장을 동시에 분석하였다. 분석 결과는 선천적 브랜디드콘텐츠와 후천적 브랜디드콘텐츠로 나뉘어졌으며. 선천성 브랜디드콘텐츠는 주의-의식-흥미-협상의 단계를 거치게 되며. 이러한 소비자의 행동을 위해 제작자는 탑재-전파-지속-타협 의 과정을 수반한다. 이에 비해 후천성 브랜디드 콘텐츠는 소비자가 주의-흥미-인지-타협의 단계로 반응하며, 소비자의 행동을 위해 제작자는 콘텐츠를 전달함에 있어 전파-지속-탑재-타협의 과정을 보여주었다. '탑재'와 '타협'은 브랜디드콘텐츠의 대표적 특징이며, 선천성/후천성 브랜디드콘텐츠의 소비자 이탈단계가 서로 상이하다는 점 또한 발견할 수 있었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.330-339
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• 2008

Ground-based interceptors(GBI) comprise a major element of the strategic defense against hostile targets like Intercontinental Ballistic Missiles(ICBM) and reentry vehicles(RV) dispersed from them. An optimum design of the subsystems is required to increase the performance and reliability of these GBI. Propulsion subsystem design and optimization is the motivation for this effort. This paper describes an effort in which an entire GBI missile system, including a multi-stage solid rocket booster, is considered simultaneously in a Genetic Algorithm(GA) performance optimization process. Single goal, constrained optimization is performed. For specified payload and miss distance, time of flight, the most important component in the optimization process is the booster, for its takeoff weight, time of flight, or a combination of the two. The GBI is assumed to be a multistage missile that uses target location data provided by two ground based RF radar sensors and two low earth orbit(LEO) IR sensors. 3Dimensional model is developed for a multistage target with a boost phase acceleration profile that depends on total mass, propellant mass and the specific impulse in the gravity field. The monostatic radar cross section (RCS) data of a three stage ICBM is used. For preliminary design, GBI is assumed to have a fixed initial position from the target launch point and zero launch delay. GBI carries the Kill Vehicle(KV) to an optimal position in space to allow it to complete the intercept. The objective is to design and optimize the propulsion system for the GBI that will fulfill mission requirements and objectives. The KV weight and volume requirements are specified in the problem definition before the optimization is computed. We have considered only continuous design variables, while considering discrete variables as input. Though the number of stages should also be one of the design variables, however, in this paper it is fixed as three. The elite solution from GA is passed on to(Sequential Quadratic Programming) SQP as near optimal guess. The SQP then performs local convergence to identify the minimum mass of the GBI. The performance of the three staged GBI is validated using a ballistic missile intercept scenario modeled in Matlab/SIMULINK.