• 제어로봇시스템학회논문지
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• 제3권1호
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• pp.46-51
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• 1997

The optimal control of a continuous process has been performed using genetic algorithms(GAs). GAs are robust and easily applicable for complex and highly nonlinear problems. We introduce the heuristics 'dynamic range' which reduces the search space dramaticaly keeping the robust search of GAs. GAs with dynamic range show the better performance than SQP(Successive Quadratic Programing) method which converges to a local minimum. The proposed methology has been applied to the optimal control of the continuous MMA-VA copolymerization reactor for the production of the desired molecular wieght and the composition of VA in dead copolymer.

• 한국응용과학기술학회지
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• 제41권2호
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• pp.318-328
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• 2024

본 연구에서는 수크로스 스테아레이트(SS)의 유화력과 가용화력을 좀 더 향상시키기 위해, sodium deoxycholate (SDOC)와 PEG-40 hydrogenated castor oil (HCO)와의 혼합 조성물을 구성하였다. 혼합물의 최적 조성을 구하기 위해 혼합물 실험 계획법을 도입하여 실험을 진행하고, 실험에서 얻은 데이터를 회귀 분석하여 혼합물 조성의 변화가 혼합물의 특성에 미치는 영향을 살펴보았다. SS에 SDOC만을 첨가했을 때 코코넛 오일에 대한 유화력이 가장 향상되고, HCO만을 첨가했을 때는 가용화력이 가장 향상된 반면, 에스테르 오일인 cetyl ethylhexanoate (CEH)에 대한 유화력은 SDOC와 HCO를 함께 첨가했을 때 가장 크게 향상됨을 알 수 있었다. 코코넛 오일 및 CEH 각각에 대한 유화력과 가용화력, 3개의 특성치에 대한 동시 최적화를 실시한 결과, 최적의 계면활성제 혼합 조성은 SS 0.7939, SDOC 0.0586, HCO 0.1475로 구해졌다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1299-1304
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• 2014

The electrochemical performance of Li-S cells was investigated in various ternary electrolyte solutions composed of 1,2-dimethoxyethane (DME), tetra(ethylene glycol) dimethyl ether (TGM), and 1,3-dioxolane (DOX). The discharge capacity values and cycle data obtained at each composition were statistically treated with the Minitab program to obtain mixture contour plots, from which the optimal composition of the ternary solvent systems was predicted. The discharge capacities and capacity retention were quite dependent on the electrolyte composition. It was estimated from the contour plots of the capacity at 1.0 C that the discharge capacity sharply increased with a decrease in the TGM content. High capacities greater than 900 mAh/g at 1.0 C were expected for the electrolyte composition with a volume ratio of DME/TGM/DOX = 1/0/1. In contrast, it was predicted from the mixture contour plot of the capacity retention that the cycle performance would significantly increase with an increase in the DME content.

• Journal of Microbiology and Biotechnology
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• 제28권9호
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• pp.1502-1510
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• 2018

Organic solvent-tolerant (OST) enzymes are widely applied in various industries for their activity and stability in organic solvents, for their higher substrate solubility, and for their greater stero-selectivity. However, the criteria for identifying OST enzymes largely remain undefined. In this study, we compared the amino acid composition of 19 OST esterases with that of 19 non OST esterases. OST esterases have increased the ratio of Ala and Arg residues and decreased the ratio of Asn, Ile, Tyr, Lys, and Phe residues. Based on our amino acid composition analysis, we cloned a carboxylesterase (EstSP2) from a psychrophilic bacterium, Sphingomonas glacialis PAMC 26605, and characterized its recombinant protein. EstSP2 is a substrate specific to p-nitrophenyl acetate and hydrolyzed aspirin, with optimal activity at $40^{\circ}C$; at $4^{\circ}C$, the activity is approximately 50% of its maximum. As expected, EstSP2 showed tolerance in up to 40% concentration of polar organic solvents, including dimethyl sulfoxide, methanol, and ethanol. The results of this study suggest that selecting OST esterases based on their amino acid composition could be a novel approach to identifying OST esterases produced from bacterial genomes.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.80-83
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• 2009

Application of UV curing technique for poly vinyl chloride (PVC) floor tiles coating has improved the quality of PVC floor. Various formulations including acrylated oligomers based on a polyurethane were blended with reactive monomers, photoinitiators and other additives. The used oligomers are commercial aliphatic urethane acrylates. Thin films were prepared on PVC tiles by bar coating with different formulations using UV radiation. The coating resins were characterized by FTIR. The properties of UV-cured films such as gloss grade and adhesion were examined. The properties of UV-cured films dependent on the influence of composition and processing conditions was studied. The investigation was conducted to achieve an optimal domain of composition and desired coating effect.

• 한국CDE학회논문집
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• 제13권6호
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• pp.421-428
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• 2008

This article investigates the fabrication of polycaprolactone (PCL) composites filled with different volume fractions (10-30%) of tricalcium phosphate (TCP) by selective laser sintering (SLS) for tissue engineering scaffolds. Optimal processing parameters for each composition were developed by design of experiments (DOE). Specimens for compressive testing for each composition were fabricated and tested. The results showed that the compressive modulus increases as a function of TCP volume fraction. The experimentally measured compressive moduli were compared with moduli predicted by Halpin's theoretical model and were found to be in excellent agreement. This result proved that experimentally determined processing parameters for each composition were well optimized.

• 한국수산과학회지
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• 제49권5호
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• pp.607-611
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• 2016

This study was conducted to investigate the effects of different water temperatures on growth, survival, biochemical composition, and blood physiological parameters of juvenile mandarin fish Siniperca scherzeri. Feed-trained juvenile fish were subjected to four water temperatures (20, 23, 26 and 29℃) with two replicate groups. The fish were fed to apparent satiation twice daily using a formulated diet containing 55% crude protein and 6% crude lipid. After the 8-week feeding trial, survival was >96% in all groups. Weight gain and feed efficiency of fish reared at 26 and 29℃ were higher than those reared at 20℃. The protein efficiency ratio, daily feed intake, and whole body proximate composition were not affected by water temperature. These results indicate that a suitable water temperature range for optimal growth and feed efficiency of juvenile mandarin fish is 26-29℃ under these experimental conditions.

• 로봇학회논문지
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• 제17권1호
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• pp.93-101
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• 2022

Bioheavy oil, which is expanding its range of use as an alternative fuel to reduce environmental pollutant emissions, has a lot of difficulty in combustion due to its low emission of pollutants such as nitrogen oxide (NOx) and sulfur oxide (SOx), while its low dissipation and high oxygen content in fuel. many studies have been conducted on change in characteristics by mixing rate combustion characteristics and combustion reactions, but there have been no specific and effective studies on the composition of control system, optimization of control, development of logic for mixing and burning, minimizing environmental pollutantants discharge. In this study, we intend to consider systemmatic and empirical considerations on the composition, logic development, solve the problem of manual switching of bioler master due to excessive oxygen content and tuning of the control system for optimal combustion of bioheavy oil.

• 한국생산제조학회지
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• 제22권1호
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• pp.173-177
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• 2013

The purpose of this paper is to investigate the influences on mechanical properties of two-stroke cycle motor pistons manufactured by casting, conventional forging and powder forging, through the comparison of characteristics, merits and disadvantages of each forming technology. For each forming technology, the optimal process parameters were determined through the experiments for several conditions, and microstructure, hardness, tensile strength and elongation of pistons are compared and analyzed. In conventional forging process, material temperature was $460^{\circ}C$ and the die temperature was $210^{\circ}C$ for the Al 4032. The optimal condition was found as solution treatment under $520^{\circ}C$ for 5 hours, quenching with $23^{\circ}C$ water, and aging under $190^{\circ}C$ for 5 hours. In powder forging process, the proper composition of material was determined and optimal sintering conditions were examined. From the experiment, 1.5% of Si contents on the total weight, $580^{\circ}C$ of sintering temperature, and 25 minutes of sintering time were determined as the optimal process condition. For the optimal condition, the pistons had 76.4~78.3 [HRB] of hardness, and 500 [MPa] of tensile strength after T6 heat treatment.

• 미생물학회지
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• 제29권6호
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• pp.387-391
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• 1991

Methylobacterium extorquens AM1 growing on methanol as a sole source of carbon and energy was found to grow most rapidly (t$t_{d}$ =6h) at 30.deg.C in a mineral medium (pH 7.0) containing 0.5% (v/v) methanol which was agitated at 200 rpm (optimal cultivation condition). Cells grown under the optimal cultivation condition contained more spermidine, but less putrescine, than the cells grown on 2.5%(v/v) ( $t_{d}$ =8h ) or at 20.deg.C ( $t_{d}$ =8h ). Cells cultivated under the optimal condition was found to contain more spermidine than the cells grown at pH 6.0 (( $t_{d}$ =7h ) and pH 8.0 ($t_{d}$ =7.3h). the cells growing at the stationary phase under the optimal condition accumulated more spermine or putrescine than the cells growing at the same phase on 2.5%(v/v) methanol or at pH 6.0 and pH 8.0, respectively. M. extorquens AM1 grown in a medium agitated at 100 rpm ( $t_{d}$ =8.8h ) contained less spermidine and spermine than the cells grown under the optimal cultivation condition.