• 상하수도학회지
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• 제19권4호
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• pp.421-428
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• 2005

Dissolved air flotation (OAF) is a solid-liquid separation system that uses fine bubbles rising from bottom to remove particles in water. In this study, we investigated the effect of L/W (L; Length, W; Width) on the hydro-dynamic behavior in DAF system using CFD (Computational Fluid Dynamics) and ADV (Acoustic Doppler Velocimetry) technique. The factual full-scale DAF system, L/W ratio of 1:1, was selected and various L/W ratio (2:1, 3:1, 4:1 and 5:1) conditions were simulated with CFD. For modelling, 2-phase (gas-liquid) flow equations for the conservation of mass, momentum and turbulence quantities were solved using an Eulerian-Eulerian approach based on the assumption that very small particle is applied in the DAF system. Also, for verification of CFD simulation results, we measured the factual velocity at some points in the full-scale DAF system with ADV technique. Both the simulation and the measurement results were in good accordance with each other. As the results of this study, we concluded that L/W ratio and outlet geometry play important role for flow pattern and fine bubble distribution in the flotation zone. In the ratio of 1:1, the dead zone is less than those in other cases. On the other hands, in the ration of 3:1, the fine bubbles were more evenly distributed.

• 대한기계학회논문집B
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• 제24권11호
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• pp.1437-1446
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• 2000

A numerical analysis on the freeze coating process of a non-isothermal finite dimensional plate with a binary alloy is performed to investigate the growth and decay behavior of the solid and the mushy layer of the freeze coat and a complete procedure to calculate the process is obtained in this study. The continuously varying solid and mushy layers are immobilized by a coordinate transform and the resulting governing differential equations are solved by a finite difference technique. To account for the latent heat release and property change during solidification, proper phase change models are adopted. And the convection in the liquid melt is modeled as an appropriate heat transfer boundary condition at the liquid/mushy interface. The present results are compared with analytic solutions derived for the freeze coating of infinite dimensional plates and the discrepancy is found to be less than 0.5 percent in relative magnitude for all simulation cases. In addition the conservation of thermal energy is checked. The results show that the freeze coat grows proportional to the 1.2 square of axial position as predicted by analytic solutions ar first. But after the short period of initial growth, the growth rate of the freeze coat gradually decreases and finally the freeze coat starts to decay. The effects of various non-dimensional processing parameters on the behavior of freeze coat are also investigated.

• 한국약용작물학회지
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• 제12권6호
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• pp.494-499
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• 2004

체세포배발생을 이용한 가시오갈피 대량증식체계 확립을 위하여 저온처리에 의한 체세포배의 장기저장 실험을 수행하였다. 현탁배양 체세포배의 $4^{\circ}C$에서의 저온저장에는 구형배 이전의 조기단계의 체세포배가 적합하였고 $2\;g/{\ell}$ 이하의 낮은 접종밀도에서는 36개월 이상 저장이 가능하였다. 장기간 저온 저장한 체세포배는 상온에 옮긴 후 2,4-D를 첨가한 배지에서만 성장을 회복하여 배발생캘러스를 형성하였으며 배발생캘러스의 증식속도는 배양온도를 $32^{\circ}C$로 높였을 때에 가장 효율적이였다.

• 조명전기설비학회논문지
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• 제24권2호
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• pp.77-85
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• 2010

최근, LCD(Liquid Crystal Display) 산업에서 클린룸의 규모가 커짐에 따라 Stocker 시스템의 사이즈가 커지고 길이가 장거리화 되고 있다. 이에 제조업체는 생산수율을 높이기 위해 Stocker 시스템의 전체 택타임을 줄이기 위한 방안으로 Stocker 시스템의 속도 증가와 고유가 시대에 여러 장비들에 대한 에너지 절약을 통한 공장 운영비용이 최소화되도록 요구하고 있다. 따라서 본 논문은 차세대 Stocker 시스템의 에너지 절감과 이송 속도증가에 따른 고효율 비접촉 전원시스템(CPS, Contactless Power Supply)의 최적설계를 제안하고, 에너지 절감을 위한 비접촉 전원시스템의 시제품을 제작하여 부하인 크레인의 여러 운전 패턴에 따른 비접촉 전원시스템의 실증시험과 입/출력 특성, 효율 개선에 따른 최적화로 개발된 비접촉 전원 시스템의 에너지 절감 효과에 대하여 서술하였다.

• 대한기계학회논문집B
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• 제35권10호
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• pp.1089-1095
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• 2011

열전달 향상을 위한 방법으로 많이 사용되고 있는 마이크로 핀을 포함한 표면 위에서의 핵비등을 액상과 기상에서 질량 및 운동량, 에너지에 대한 지배 방정식을 풀어 수치해석을 수행하였다. 핵비등에서의 기포거동을 계산하기 위해 sharp-interface 레벨셋(level-set) 방법을 상변화 효과와 핀과 캐비티와 같은 잠긴 고체에서의 점착 조건 및 접촉각, 마이크로 액체층에서의 증발 열유속을 포함하도록 수정하였다. 핀과 캐비티를 포함한 표면에서의 기포 생성, 성장, 이탈에 대한 해석을 통하여 핀-캐비티 배열, 핀-핀 간격이 핵비등에서의 기포거동에 중요한 역할을 하는 것을 확인하였다.

• KSBB Journal
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• 제31권1호
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• pp.20-26
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• 2016

This study aims to examine the optimum blanching conditions as a pretreatment condition to improve the storage stability of Dolsan leaf mustard pickle. The effects of the blan- ching temperature and time were investigated at a temperature range of $80-100^{\circ}C$. Sampling was done for 1 month after a 5 days interval. The L value of the Dolsan leaf mustard was found to be the highest at $80^{\circ}C$. The cutting force increased as the blanching temperature increased. The tensile strength decreased at $95^{\circ}C$ and $100^{\circ}C$. In addition, the sensory evaluation scores were the best at $80^{\circ}C$. The storage stability was assessed at various blanching temperatures to increase the sinigrin content during storage. Liquid chromatography with photodiode array and tandem mass spectrometry (LC-PDA/MS/MS) analysis was conducted to identify and quantify the sinigrin content in the Dolsan leaf mustard. Sinigrin as an internal standard was co-injected into each sample solution. The sample was monitored by recording the ultraviolet absorbance at 228 nm and by electrospray ionization (ESI) positive ion mode in the m/z 50-1,500 range. Blanching the sample at $80^{\circ}C$ showed the highest sinigrin concentration during storage among various temperatures and the maximum concentration was 350 ppm at 15 days storage. Study on utilization of vegetable from food processing of leaf mustard and preservation conservation results suggest that blanching at $80^{\circ}C$ is expected to improve the palatability of the pickle.

• Journal of Applied Biological Chemistry
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• 제64권1호
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• pp.33-38
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• 2021

해면동물은 강력한 세포독성을 나타내는 함유성분으로 의약후보물질 탐색의 중요한 소재로 이용되고 있으나 최근 해양생태계 보전에 관심이 높아짐에 따라 해면동물 확보는 더욱 어려움을 겪고 있다. 이러한 경향에 대응하고 해양 천연물연구의 활성화를 위한 해양생물자원 데이터베이스 구축을 위하여 181개 해면동물 추출물에 대한 HPLC 프로파일을 생성하고 항염증 및 신경세포보호 활성을 탐색하였다. 이를 통하여 해면동물 추출물 간의 HPLC를 통한 함유성분에 따른 클러스터링이 가능하였고 또한 각각 17개, 14개 시료에서 항염증 활성과 신경세포보호활성이 확인되었다. 이와 같은 연구는 해면동물을 포함한 해양생물자원에서의 효과적인 생리활성 탐색에 도움이 될 것이라고 판단한다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2021년도 춘계학술대회
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• pp.36-36
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• 2021

Cryopreservation has been broadly used as an efficient method for a long-term conservation for many types of plants especially vegetatively propagated plants. Among several cryopreservation methods, a droplet-vitrification was the most widely applicable and efficient method. Studies have developed protocols for strawberry using droplet-vitrification method and suggested the practical use of the protocol for large number of germplasm with a little modification. In this study, the droplet vitrification method of shoot tip has been tested on 31 accessions provided around the world. Shoot tips were precultured on Murashige and Skoog (MS) liquid medium supplemented with 0.3~0.5M sucrose. Precultured explants were osmoprotected with loading solution, 35% of PVS3 (C4, 17.5% glycerol and 17.5% sucrose) for 40 min and exposed to dehydration solution, PVS3 (B1, 50% glycerol and 50% sucrose) for 60 min. Then, the explants were transferred onto droplets containing 2.5 uL PVS3 on sterilized aluminum foils prior to direct immersion in liquid nitrogen (LN) for 1hr. The cryopreserved shoot tips were rapidly warmed in a water bath at 40C and then unloaded in MS with 0.8M sucrose for 40 min. The shoot tips were cultured in NH₄NO₃-free MS post culture medium for 2 weeks. Subsequently, the explants were moved to the MS medium for 6 weeks and evaluated the regrowth rate. By this droplet-vitrification protocol, twenty-four accessions showed at least 40% regrowth rate. Out of 24 accessions, 'Nonsan1ho' had the highest regeneration rate of 85.8% and 'Jumbo pureberry' had the lowest with 42.1%.

• 한국균학회지
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• 제15권1호
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• pp.29-37
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• 1987

창덕궁의 유물고에 소장되어 있는 섬유질 문화재로부터 섬유소 분해균을 분리하기 위하여 두 단계의 선별을 거쳐서 섬유소 분해능이 강력한 Cellulolytic fungus를 분리하였다. 이 균주는 형태학적인 분류기준을 통하여 Aspergillus clavatus로 동정되었다. 이 균주에서 CMC 액체배지에서의 CMCase, avicelase와 salicinase의 생성은 $30^{\circ}C$의 shaking culture 조건에서 5 일에 가장 높았으며, 그 이후는 점차 감소하였다. crude extracellularenzyme 을 $70%(NH_4)_2SO_4$ 포화용액에서 침전시켜 20mM acetate buffer(pH 6.0)로 dialysis시킨후 효소에 대한 여러가지 성질을 비교하였다. CMCase와 avicelase의 최적 pH는 모두 pH6.0으로 중성에 가까왔으며 두 효소의 최적온도는 모두 $50^{\circ}C$이었다. 효소의 열에 대한 안정도에서는 CMCase, avicelase 모두 $30-50^{\circ}C$에서 안정성을 유지하였고 또한 효소의 활성에 미치는 기질농도의 영향을 보먼 CMCase는 1.5%에서 avicelase는 2.2%에서 최고의 활성을 나타냈다. 금속이온의 영향을 살펴본 결과 $Mg^{++}$와 $Ca^{++}$는 5mM에서 효소의 활성이 최고에 달하였으며 $Cu^{++}$와 $Zn^{++}$에서는 농도가 증가할수록 효소의 활성이 저해되었다. 또한 이 균주의 섬유소 분해효소는 2-mercaptoethanol, $I_2$, $NaN_3$ 등의 저해제에 의하여 활성이 크게 저해되었다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.37-37
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• 2018

We use two different methods for laboratory propagation from seed of lady's slipper orchid(Cypripedium macranthos Sw.); immature seed which also called green capsule or fully mature seed about 120~130 days from pollination. In green capsule culture, the seed pods should be collected within precisely right time. The right time of seed collection could be diverse under the wether conditions or nutritional factors of the plants. In fully matured seed culture, the more complicated procedures are needed to break the dormancy of the seed; thermal or chemical treatment. The seedlings in this study were easily germinated from immature seeds in Harvais medium; 53 days after pollination(DAP) in Cypripedium pubescens, DAP 65 in C. parviflorum and C. macranthos. The germinated seedlings were transplanted to hormone free media immediately to avoid abnormal growth of seedlings. When the seedlings have roots with a minimum length of around 2-3cm and have visible dormant buds, the seedlings were removed from the flask and stored in refrigerator for vernalization. To examine the correlation of seedlings and maternal plants, the 125 seedlings of C. macranthos were transplanted in the soil bed at a distance of 20-100 cm from mother plants on April 20. The survival rate of seedlings were 92% in 20 cm distance from the ripe plants, and 56 % in 100 cm distance. The seedlings which were transplanted near mother plants showed vigorous growth in plant height, leaf width, and especially dormant buds. Considering the existence of mycorrhiza which is a symbiotic association between a fungus and the roots of a orchid vascular, the various fungus from mother plants could affect the growth of the seedlings. These results indicate the possibility of high and stable production and practical industrialization of endangered lady's slipper orchids.