• 한국산학기술학회논문지
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• 제12권11호
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• pp.4726-4731
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• 2011

본 논문에서는 배치 단위로 이루어지는 플런지연삭의 최적 연삭 조건 선정을 위한 알고리즘을 제안하였다. 제안된 알고리즘은 연삭공정을 나타내는 상태변수를 선정하고 선정된 상태 변수를 바탕으로 각 사이클에서 이루어지는 최적의 연삭 조건을 GA(Genetic Algorithm)를 이용하여 선정하였다. 이를 바탕으로 전체 배치 단위의 최적 연삭조건은 DP(Dynamic Programming)를 이용하여 구하였다. 제안된 알고리즘을 시뮬레이션을 통해 그 가능성을 검증하였다.

• International Journal of Industrial Entomology and Biomaterials
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• 제35권2호
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• pp.83-88
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• 2017

Silk is appealing materials for many biomedical applications involving tissue engineering and implantable devices, because of its biocompatibility, environmental stability, controlled proteolytic biodegradability and morphologic flexibility. Silk matrix is required for the treatment of a wide wound area, but the present silk matrix is made by the second processing, and thus, the labor and the cost are high. In this work, we investigated the optimal production condition of natural silk 3D matrix using the silkworms and invented Automatic Silk Matrix Making Machine (ASMMM) for natural silk 3D matrix production. As a result, we determined that optimal production condition for making A4 paper size natural silk 3D matrix was used Rough aquarelle paper on surface at $25^{\circ}C$ and 30 silkworm larvae. These results are expected to provide basic data for the efficient production of the natural silk 3D matrix, and it is suggested that the produced natural silk 3D matrix is useful as a medical biomaterials.

• 오토저널
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• 제14권6호
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• pp.113-126
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• 1992

Recently the multi-kind, small-amount manufacturing system has been replacing the mass manufacturing system, and domestic machining inustry also is eager to absorb the new technology because of its high productivity and cost reduction. The optimization of the cutting condition has been a vital problem in the machining industry, which would help increase the productivity and raise the international competitiveness. It is intended in this study to investigate the machining costs per unit time which is essential to the analysis of the optimal cutting condition, to computer the cutting speed that lead to the minimum machining costs and the maximum production to suggest the cutting speed range that enables efficient speed cutting, and to review the machining economy in relation to cutting depth and feed. Also considered are the optimal cutting speed and prodution rated in rrelation with feed. It is found that the minimum-cost cutting speed increases and the efficient cutting speed range is reduced as machining cost per unit time increases since the cutting speed for maximum production remains almost constant. The machining cost is also lowered and the production rate increases as the feed increases, and the feed should be selected to satisfy the required surface roughness. The machining cost and production rate are hardly affected by the cutting depth if the cutting speed stays below 100m/min, however, they are subject to change at larger cutting depth and the high-efficient speed range also is restricted. It can be established an adaptive optimal cutting conditions can be established in workshop by the auto-selection progam for optimal operation. It is expected that this method for choosing the optimal cutting conditions might contribute to the improvement of the productivity and reduced the cost. It is highly recommended to prepare the optimal cutting conditionthus obtained for future use in the programing of G-function of CNC machines. If proper programs that automatically select the optimal cutting conditions should be developed, it would be helpful to the works being done in the machine shops and would result in noticeable production raise and cost reduction.

• 한국정밀공학회지
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• 제19권9호
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• pp.111-117
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• 2002

In most machining companies, operators decide the cutting condition, a pair of spindle speed (5) and table federate (F) by experience and subjective judgment. As cutting conditions are determined by operators' experience and ability, inconsistent cutting conditions are given in same operating conditions. The objective of this study is to develop the cutting condition decision system which utilizes shop data and predicts tool life by neural network and eventually leads to the optimal cutting condition. The production time per piece is considered for an optimization object. We will discuss the process of an optimal cutting condition decision by neural network. By this process, a series of shop data is stored. And neural network is constructed for prediction of tool life and the optimal cutting condition is recommended from a cutting condition decision system using the stored shop data. The results show that the developed system is rational in searching the optimal cutting conditions on job operations.

• 한국식품영양과학회지
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• 제31권4호
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• pp.572-577
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• 2002

Gluconacetobacter persimmonus KJ145를 사용하여 bacterial cellulose 생산에 최적 배지와 배양조건을 설정하였다. Bacterial cellulose를 생성하기 위한 최적배지로는 HS배지보다는 천연사과과즙이 더 우수한 경향을 나타내었으며, 사과과즙에 각종 탄소원을 보강한 결과 탄소원으로 pyruvate가 적합하였다. 탄소원의 농도를 조사한 결과, 1%가 적합하였으며, 각종 질소원의 영향을 조사한 결과 CSL이 가장 우수한 결과를 나타내었다. CSL의 농도에 따른 bacterial cellulose의 생산성을 조사한 결과, 10% 농도에서 가장 좋았다. Bacterial cellulose의 생성에 미치는 배지의 초기 pH의 영향을 조사한 결과 pH 6.0에서 최적이었으며,배양온도별 영향을 조사한 결과 35$^{\circ}C$에서 하는 것이 최적이었다. 최적 배양조건에서 배양시간별로 생성되는bacterial cellulose의 양을 조사한 결과 16일간 배양하는 것이 가장 좋았으며, 이 때 생성되는 bacterial cellulose의 생산량은 8.96 g/L으로 비교적 높았다.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.220-228
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• 1995

For polyhydroxyalkanoic acid (PHA) production, several microorganisms were isolated from sewage sludge. One of them, GB-77 strain, was chosen from its PHB/HV copolymer production on only fructose without cosubstrate. The isolated strain GB-77 was identified as the genus Alcaligenes. Optimal temperature and pH for cell growth were 36C and 6.8. Optimal medium composition was 10 g/l of fructose and 5 g/l of polypeptone, 1 $\times$ 10$^{-2}$M Na$^{2}$HP0$^{4}$, 1.3 $\times$ 10$^{-2}$M KH$^{2}$PO$^{4}$. To investigate the optimal condition for polyhydroxyalkanoic acid production two-stage culture technique was used; first stage for cell growth and second stage for PHA production on unbalanced growth conditions. Optimal conditions for high PHA production were C/N ratio 50, temperature 36$\circ$C and pH 6.8. To overcome fructose inhibition on cell growth, intermittent feeding fed-batch culture technique was used. Total cell concentration was 17.4 g/l with 9.1 g/l of PHA. The purified PHA was identified PHB/HV copolymer by NMR analysis.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.525-528
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• 2001

본 연구는 메탄을 최대로 발생시킬 수 있는 최적조건을 탐색하는데 있다. 메탄을 많이 발생 시킬 수 있는 최적 온도와 pH를 결정한 다음, 여러 가지 탄소원에 대해 조사하였다. 온또는 $25^{\circ}C$. $30^{\circ}C$. $55^{\circ}C$에서, pH 는 pH 2, 4, 6, 8. 10 에서 , 그리고 탄소원은 methanol. formic acid. sodium acetate. succinic acid, glucose 에서 조사하였다. 결과적으로 볼 띠 1. 온도는 $55^{\circ}C$. pH 는 중성부근. 탄소원은 methanol 인 조건에서 가장 많은 메탄을 얻을 수 있었다.

• Environmental Engineering Research
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• 제20권2호
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• pp.121-125
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• 2015

Biohydrogen production from food waste via dark fermentation was conducted by using mixed culture under various environmental conditions (initial pH, initial F/M ratio, initial ferrous iron ($Fe^{2+}$), and temperature condition) in batch reactor. The results revealed that the maximum hydrogen yield of $46.19mL\;H_2/g\;COD_{add}$ was achieved at the optimal conditions (initial pH 8.0, initial F/M ratio 4.0, initial iron concentration 100 mg $FeSO_4/L$ and thermophilic condition ($55{\pm}1^{\circ}C$)). Furthermore, major volatile fatty acid (VFA) productions of butyrate (765.66 mg/L) and acetate (324.69 mg/L) were detected and COD removal efficiency was detected at 66.00%. Therefore, these optimal conditions could be recommended to operate a system.

• 환경위생공학
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• 제5권2호
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• pp.103-110
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• 1990

For production of thermophilic and alkaline protease, Bacillus sp. strain AP-5 was isolated from a compost. The production of the protease was reached at maximum for 4 days at $55^{\circ}$ in standing culture. Chitin and Cellulose as carbon source, and Skim Milk as nitrogen source were favorable for the production of the enzyme. Optimal temperature and optimal pH of the enzyme was $55^{\circ}$ and 11, respectively. Metal ion didn't effect on the enzyme activity, the protease was very stable at heat treatment of 30 min at $55^{\circ}$.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.92-99
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• 2012

The optimal physical factors affecting enzyme production in an airlift fermenter have not been studied so far. Therefore, the physical parameters such as aeration rate, pH, and temperature affecting PLA-degrading enzyme production by Actinomadura keratinilytica strain T16-1 in a 3 l airlift fermenter were investigated. The response surface methodology (RSM) was used to optimize PLA-degrading enzyme production by implementing the central composite design. The optimal conditions for higher production of PLA-degrading enzyme were aeration rate of 0.43 vvm, pH of 6.85, and temperature at $46^{\circ}C$. Under these conditions, the model predicted a PLA-degrading activity of 254 U/ml. Verification of the optimization showed that PLA-degrading enzyme production of 257 U/ml was observed after 3 days cultivation under the optimal conditions in a 3 l airlift fermenter. The production under the optimized condition in the airlift fermenter was higher than un-optimized condition by 1.7 folds and 12 folds with un-optimized medium or condition in shake flasks. This is the first report on the optimization of environmental conditions for improvement of PLA-degrading enzyme production in a 3 l airlift fermenter by using a statistical analysis method. Moreover, the crude PLA-degrading enzyme could be adsorbed to the substrate and degraded PLA powder to produce lactic acid as degradation products. Therefore, this incident indicates that PLA-degrading enzyme produced by Actinomadura keratinilytica NBRC 104111 strain T16-1 has a potential to degrade PLA to lactic acid as a monomer and can be used for the recycle of PLA polymer.