• 멤브레인
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• 제15권3호
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• pp.198-205
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• 2005

방사능 오염도 측정에 사용하기 위한 이중구조 고분자막이 폴리설폰과 세륨활성화된 이트륨실리케이트(CAYS)를 이용하여 제조되었다. 제조된 막은 순수 고밀도 고분자 지지층과 이에 제막된 고분자 용액의 상전환 공정에 의해 고형화된 CAYS 함침 활성층의 이중구조로 구성된다. 제막공정에서 대기방치 공정이 생략되었을 때 CAYS를 포함하는 활성층은 전형적인 비대칭 구조를 지니며, CAYS 입자들이 고분자 구조 사이에 박혀있는 형상을 지닌다. 제막공정에서 대기에 방치하는 시간이 증가할수록 막의 형상은 스폰지 구조를 띠며 CAYS는 고분자 구조로부터 분리되어 막 내부에 셀 같은 공간에 밀집되어 존재함을 보였다. 한편, 두 충 사의 계면형상은 고분자 고형화 과정에서의 상전환 속도와 밀접한 관련되었으며, 대기방치 시간의 증가에 따라 계면의 구분이 뚜렷하게 나타나지 않았다. 방사능 탐지 특성에서 스폰지 구조를 지니는 막의 고분자 구조는 방사성핵종이 통과할 수 없는 밀집된 형상을 지니면서 탐지효율의 감소를 초래하는 것으로 나타났다.

• 한국식품조리과학회지
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• 제17권5호
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• pp.503-509
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• 2001

The effects of salting methods on textural properties of Kakdugi were evaluated during fermentation at 1$0^{\circ}C$ for up to 52 days. Kakdugi samples were prepared by 4 different salting methods at final salt concentration of 1.5%, which is appropriate for organoleptic quality. The salting methods for radish cubes(2 cm size) of Kakdugi were as follows; 1) Treatment S-1: spraying dry salt uniformly on to the radish cubes at 1.5%(w/w) and holding for 1 hr, 2) Treatment S-5: spraying dry salt uniformly on to the radish cubes at 1.2%(w/w) and holding for 5 hr, 3) Treatment B-1: brining radish cubes in a 8.5%(w/v) salt solution for 1 hr, 4) Treatment B-5: brining radish cubes in a 4.0%(w/v) salt solution for 5 hr. The contents of water soluble pectin, total soluble solid and PG activity were increased as the fermentation periods increased. A majority of total dietary fiber(TDF) consisted of soluble dietary fiber(SDF), and the amount of insoluble dietary fiber(IDF) was relatively small in Kakdugi during fermentation. Furthermore, an increase in SDF and a consequent decrease in IDF contents were observed with the fermentation time increased.

• Journal of Advanced Marine Engineering and Technology
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• 제30권6호
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• pp.709-715
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• 2006

The effects of thermal cycle condition and applied stress on the intergranular corrosion in austenitic 316 type stainless steels were investigated. Specimens were solution-treated at 1100$^{\circ}C$ for one hour and then sensitized in the temperature range of $500{\sim}800^{\circ}C$ by holding $2{\sim}300s$ with a various applied stresses of $0{\sim}8kg/mm^2$. Degree of sensitization. DOS %, was measured through polarization curve by electrochemical DL-EPR test. Microstructural observations were also conducted DOS % increased with an increase of sensitization temperature and/or holding time. Increase of applied stress resulted in increase of DOS % and more corroded surface because of acceleration of intergranular corrosion and fine grain size due to the stress. Cr depleted zone near grain boundary was observed. The amount of depletion was profounded with an increase of sensitization temperature, holding time and applied stress. $M_{23}C_6$ carbides were precipitated discontinuously at grain boundary. However, its amount was relatively small in the thermal cycle condition of 800$^{\circ}C$, 300sec and 4kg/mm$^2$.

• 열처리공학회지
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• 제26권4호
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• pp.165-172
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• 2013

In the present study, the microstructure and solution treatment response of Al-Zn-Mg alloys bars by thixo-extrusion was investigated. The alloy bars were solution treated at 400, 430, 460 and $490^{\circ}C$ for various times. In order to examine the microstructures and phase analysis of the samples after solution treatment, it was performed by optical and scanning electron microscopy. And, Vickers hardness and electrical conductivity was measured on the solution treated samples for each condition to investigate the solution treatment response of extruded bars during solution treatment. The results show that the optimum solution heat treatment conditions of thixo-extruded Al-Zn-Mg alloy for minimization of the grain growth and degradation promotion of the second phase is a temperature of $460^{\circ}C$ and holding time of 0.5 to 2 h.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2003년도 추계학술대회 및 정기총회
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• pp.81-84
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• 2003

The ability to determine the optimal frequencies and offsets for independent and unrestricted ordering cycles for multiple items can be very valuable for managing storage capacity constrained facilities in a supply chain. The complexity of this problem has resulted in researchers focusing on more tractable surrogate problems that are special cases of the base problem. Murthy et al. (European Journal of Operation Research 2003) developed insights leading to solution of the original problem and present a heuristic for offsetting independent and unrestricted ordering cycles for items to minimize their joint storage requirements. However, their study cannot find optimal solution due to the Greedy Heuristic solution procedure. In this paper, we present a complete procedure to find the optimal solution for the model with a integer programming optimization approach and genetic algorithm. Numerical examples are included to compare each model with that of Murthy et at. Research of this type may prove useful in solving the more general problem of selecting order policies to minimize combined holding, ordering, and storage costs.

• 화훼연구
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• 제19권1호
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• pp.42-48
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• 2011

본 연구는 수확 후 몇가지 전, 후처리가 자생식물인 벌개미취의 수명과 품질에 미치는 영향을 구명하여 벌개비취를 상품성이 있는 절화로 개발하고자 수행되었다. 수확 후 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3+50mg{\cdot}L^{-1}$ BA와 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3$ + $150mg{\cdot}L^{-1}$ citric acid 용액에 16시간 동안 전처리한 경우 증류수구보다 절화수명이 1.4배 길어졌다. 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3$ + $50mg{\cdot}L^{-1}$ BA와 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3$ + $50mg{\cdot}L^{-1}\;GA_3$ 보존용액에 계속 침지한 벌개미취는 증류수에 비해 절화수명이 1.6배와 1.7배 길어졌다. 이 처리에서 생체중이 증가되고 수분균형도 늦게까지 플러스 값을 유지하여 절화수명이 길어짐을 알 수 있었다. 벌개미취 절화수명에 생체중과 수분균형이 매우 큰 영향을 미치는 것으로 판단되었다.

• 전기학회논문지
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• 제56권1호
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• pp.167-173
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• 2007

This paper describes a redundancy resolution based method for determining an optimal initial configuration of a humanoid robot for holding an object. There are three important aspects for a humanoid robot to be able to hold an object. Those three aspects are the reachability that guarantees the robot to reach the object, the stability that guarantees the robot to remain stable while moving or holding the object, and the manipulability that makes the robot manipulate the object dexterously. In this paper, a humanoid robot with 20 degrees of freedom is considered. The humanoid robot is kinematically redundant and has infinite number of solutions for the initial configuration problem. The complex three-dimensional redundancy resolution problem is divided into two simple two-dimensional redundancy resolution problems by incorporating the symmetry of the problem, robot's moving capability, and the geometrical characteristics of the given robot. An optimal solution with respect to the reachability, the stability, and the manipulability is obtained by solving these two redundancy resolution problems.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.197-203
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• 1999

Stainless steels in general has passive film having strong corrosion resistance on surface. Therefore it must be necessarily removed by etching in mixing solution of sulfuric and chloric acid before Nitriding treatment. But in the ion nitriding, nitride layer was easily formed because passive film was removed without difficult by sputtering effect. The removal extent of these passive films was greatly effected by gas mixing ratios and pressure and holding times of pre sputtering factors in pre sputtering stage. As a results of experiment it has been known that pre sputtering pressure and holding time was not nearly effective on the formation behavior of nitride layer. But when A/H2 gas mixing ratios was 1/2 (vol%) was the most effective of the all pre sputtering conditions. It was resulted from the combination of mechanical reaction byArgon bombardment and chemical reaction by reduction of hydrogen on the passive film.

• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.218-223
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• 2008

A new Pareto-optimal design algorithm, requiring least computational work, is proposed for a single phase AC solenoid actuator with multi-design-objectives: maximizing holding force and minimizing eddy current loss simultaneously. In the algorithm, the design space is successively reduced by a suitable factor, as iteration repeats, with the center of pseudo-optimal point. At each iteration, the objective functions are approximated to a simple second-order response surface with the CCD sampling points generated within the reduced design space, and Pareto-optimal solutions are obtained by applying($1+{\lambda}$) evolution strategy with the fitness values of Pareto strength.

• 한국식품영양과학회지
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• 제31권6호
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• pp.999-1004
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• 2002

식염농도를 3, 5, 7 및 9%로 각각 조제한 2$^{\circ}C$의 염지액에 등심고기를 20일간 염지하면서 식염농도와 염지기간이 근원 섬유단백질의 추출성과 소편화도, 보수력, 식염함량 및 기호성에 미치는 영향을 검토하였다. 식염농도 3, 5 및 7%의 염지액에 염지한 등심고기 근원섬유단백질의 추출성과 보수력은 염지 20일까지, 근원섬유 소편화도는 염지 16일까지, 모두 식염농도가 높을수록 점점 높게 나타났으며, 9%의 염지액에 염지한 것은 일정한 경향을 보이지 않았다. 가열육의 색도는 염지액의 식염농도가 높을수록, 그리고 염지 16일까지 점점 양호하게 나타났다 염지액의 식염농도 3%에서는 염지육의 발색이 균일하게 되지 않았으며, 9%에서는 발색이 잘 되었으나 풍미와 종합적인 기호성이 좋지 않았다. 등심고기는 염지액의 식염농도5%에서 16일, 또는 7%에서 12일 염지하면 기호성이 우수하게 되었다.