• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.137-145
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• 1996

Chemical changes, lactic acid bacteria and yeast counts in kimchi prepared by a commercial manufacturer in large scale were monitored at different fermentation temperature. The optimum pH of kimchi, around pH 4.2, reached within 2 days at $25^{\circ}C$, 3 days at $15^{\circ}C$ and 23 days at $5^{\circ}C$ fermentation, respectively. The optimum acidity calculated as lactic acid was not exactly coincident with pH. The total viable count reached at maximum within 2 days at $25^{\circ}C$, 6 days at $15^{\circ}C$ and 12 days at $5^{\circ}C$ fermentation, respectively. The identified strains of Lactobacilli during kimchi fermentation were L. brevis, L. plantarum and L. acidophilus with 3 unidentified strains. L. brevis, L. plantarum appeared from the first stage of fermentation to the terminal at $15^{\circ}C$ and $25^{\circ}C$ with keeping a constant level of viable number. In case of Leuconostoc species, L. mesenteroides subsp. mesenteroides was identified. This strain increased in viable number at the beginning of fermentation and dropped sharply at all fermentation temperatures. Pediococcus species including P. pentosaceus and one unidentified strain increased at the first stage of fermentation and decreased after on. Streptococcus faecium subsp. casseliflavus which appeared at the middle stage and Aerococcus viridans which was sole strain were also confirmed during kimchi fermentation. Cryptococcus laurenti was identified at all fermentation temperature and disappeared at the first stage of fermentation. It was reappeared 10 days only after fermentation at $25^{\circ}C$.

• Food Engineering Progress
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• v.23 no.2
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• pp.87-93
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• 2019

Temperature distribution studies were performed in steam-air retort to investigate the influence of various processing conditions (come-up time, sterilization temperature, and internal pressure throughout the steam-air retort). Retort temperature data were analyzed for temperature deviations during holding phase, maximum temperature difference between test locations at the beginning and after 1, 3, and 5 min of the holding phase, and box-and-whiskers plots for each location during the holding phase. The results showed that high sterilization temperature led to a more uniform temperature distribution than low sterilization temperature (pasteurization). In pasteurization condition, the temperature stability was slightly increased by increasing pressure during the holding phase. On the other hand, the temperature stability was slightly decreased in high sterilization temperature condition. Programming of the come-up phase did not affect the temperature uniformity. In addition, the slowest cold spot was found at the bottom floor during the holding phase in all conditions. This study determined that the temperature distribution is affected by retort processing conditions, but the steam-air retort needs more validation tests for temperature stability.

• Economic and Environmental Geology
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• v.46 no.1
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• pp.11-19
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• 2013

The Daehwa Mo-W deposit is located within the Gyeonggi massif. Quartz and calcite vein mineralization occurred in the Precambrian gneiss and Jurassic granites. Three main types (Type I: liquid-rich $H_2O$ type, Type II: vapor-rich $H_2O$ type, Type III: $CO_2-H_2O$ type) of fluid inclusions were observed and are classified herein based on their phase relations at room temperature. Within ore shoots, type III fluid inclusions have been classified into four subtypes (type IIIa, IIIb, IIIc and IIId) based on their volume percent of aqueous and carbonaceous ($CO_2$) phase at room temperatures combined with their total homogenization behavior and homogenization behavior of $CO_2$ phase. Homogenization temperatures of primary type I fluid inclusions in the quartz range from $374^{\circ}C$ to $161^{\circ}C$ with salinities between 13.6 and 0.5 equiv. wt.% NaCl. Homogenization temperatures of primary type III fluid inclusions in quartz of main generation, are in the range of $303^{\circ}C$ to $251^{\circ}C$. Clathrate melting temperatures of the type III fluid inclusions were 7.3 to $9.5^{\circ}C$, corresponding to salinities of 5.2 to 1.0 equiv. wt. % NaCl. Melting and homogenization temperatures of $CO_2$ phase of type III fluid inclusions were -57.4 to $-56.6^{\circ}C$ and 29.0 to $30.8^{\circ}C$, respectively. Fluid inclusion data indicate a complex geochemical evolution of hydrothermal fluids. The Daehwa early hydrothermal system is characterized by $H_2O-CO_2$-NaCl fluid at about $400^{\circ}C$. The main mineralization occurred by $CO_2$ immiscibility at temperatures of about 300 to $250^{\circ}C$. At the late base-metal mineralization aqueous fluid formed by mixing with cooler and less saline meteoric groundwater.

• Journal of Mushroom
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• v.13 no.3
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• pp.223-227
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• 2015

The study was conducted to investigate the effects of post-incubation period and temperature treatment conditions during incubation on the uniform primordia formation and cultural characteristics of oyster mushroom (Pleurotus ostreatus). Three kinds post-incubation period; 25, 30, 35 days and control were applied for 30 days while two kinds incubation room temperature $23^{\circ}C$ and $26^{\circ}C$ and control were used $20^{\circ}C$. The substrate temperature during pre-incubation was of 'Suhan No. 1' and 'Gonji No. 7'. Oyster mushroom varieties tended to increase between $24^{\circ}C$ to $26^{\circ}C$ at 11 to 15 days after inoculation and then they were maintained in treatment temperature during post -incubation period. The $CO_2$ occurrence was at the highest at 6,500 ppm for 'Suhan No. 1' and 5,800 ppm for 'Gonji No. 7' at the time of the highest temperature increase. The ratio of un-uniformal primordia formation and the ratio of non-commercial fruit body were reduced by 40%, 10.5%, respectively compared to control for 'Suhan No. 1' when in the post-incubation temperature was $26^{\circ}C$, and incubated for 10 days and 15 days treatment. Also, 'Gonji No. 7' was reduced by 19%, 9.5%, respectively when in the post-incubation temperature was $26^{\circ}C$, and incubated for 10 days treatment. Therefore, the higher post-incubation temperature of room and longer post-incubation period resulted in the higher percentage of primordia formation of two cultivars.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.106-111
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• 2004

Fecal coliform bacteria is one of the most common cause of water quality impairments in Virginia, USA. Instream concentrations of fecal coliform (FC) bacteria were routinely monitored to assess surface water quality of the Polecat Creek watershed. Median concentration in water samples collected from 1995 to 2000 ranged from 80 cfu/100 mL to t 70 cfu/100 mL, while geometric mean concentrations ranged from 81 cfu/100 mL to 141 cfu/100 mL. The dilution and deposition by Lake Caroline may cause to lower FC concentration at monitoring site QPB, as compared FC concentration at QPD. Higher in-stream FC concentration occurred during the summer period(June-August), and lower concentration typically occurred during the winter period (December-February). This is due to more cattle in streams, and greater survival and regrowth of FC bacteria under warmer condition. The findings of this study can be helpful in planning the water quality monitoring program to avoid the inaccurate assessment of water quality due to the timing of sample collection.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.27-34
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• 2005

We have investigated the correlation between the active-layer uniformity and reliability of InGaN/GaN blue LEDs. According to initial characteristics, the devices are classified into two groups: group I devices of uniform light-emission and group II devices of non-uniform light-emission. The group II devices are more dependent on temperature and we have found two degradation mechanisms through reliability test. One is bulk degradation in which the degradation occurred over the entire chip and another one is edge degradation in which the degradation occurred from the edge of the chip. Bulk degradation caused by the nonradiative defects is found to be faster in group II devices while there is no difference in the rate of the much faster edge degradation, where darkening starts from the n-Ohmic contact edge. Therefore, more uniform active layer, more uniform current spreading, and the passivation of the dry-etched side-wall are essential for the high reliability of InGaN/GaN LEDs.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.151-154
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• 2011

$NO_x$ 제어 기술로는 크게 연소 전 탈질, 연소 개선 및 연소 후 탈질 기술로 구분할 수 있으며, 연소 후 탈질 기술에 속하는 SCR은 촉매를 사용하여 $NO_x$를 환원하는 대표적인 배연탈질기술이다. SCR의 $NO_x$ 저감 성능은 촉매 요인(촉매 구성물질, 형태, 공간속도 등)과 배가스의 온도, 유속 분포, 공정 운전 조건 등의 다양한 인자에 의해 좌우되는데 특히, 촉매층으로 유입되는 유동의 균일도는 가장 중요한 요소가 된다. 유동이 균일하지 않을 경우 촉매 전단에 편류가 발생하게 될 것이며 일정 촉매만 사용하게 되어 촉매 사용주기 감소 및 SCR 성능 저하를 초래할 수 있기 때문이다. 본 연구에서는 3차원 수치 해석 기법을 이용하여 설계 초기의 SCR 반응기 내 유동 특성을 모사하여 기류 균일도 여부를 확인하고, SCR 내 유동 균일도를 최적화시키기 위한 설계를 목적으로 설치하는 가이드 베인과 배플, 다공판이 반응기 내부 유동 및 촉매층의 기류 균일도에 미치는 영향에 대하여 연구를 수행하였다. 그 결과, 유동 개선을 위해 인입 덕트 곡관부에 가이드 베인을 설치하여 처리가스를 적절하게 배분시키고, 반응기 상단에 3단 배플을 설치한 결과 반응기 내부 유동의 편류 개선에 매우 효과적임을 알 수 있었다. 또한 다공판을 예비 촉매층 하단부 위치에 추가로 설치함에 따라 유동을 한번 더 완충시킬 수 있어 기류 균일도가 매우 양호해짐을 알 수 있었다.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.124-129
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• 1997

This study was performed to develop the biological treatment technology of wastewater polluted with heavy metals. Heavy metal-tolerant microorganisms, such as Pseudomonas putida, P. aeruginosa, P. chlororaphis and P. stutzeri possessing the ability to accumulate cadmium, lead, zinc and copper, respectively, were isolated from industrial wastewater and mine wastewater polluted with various heavy metals. The effect of several external factors, such as temperature, pH and heavy metal compounds on heavy metal accumulation in the cells was investigated. The amount of heavy metal accumulation into cells according to the kind of heavy metal compound was slightly increased in the case of the heavy metal compound with -nitrate group, but generally, there is little change according to the kind of compound in the amount of heavy metal accumulation. The amount of heavy metal accumulation according to the precultured time was increased in the case of the cell precultured for 24 hours, but generally the precultured time did not affect to the amount of heavy metal accumulation. Heavy metal accumulation into cells was affected by several external factors, such as temperature and pH. The optimum temperature and optimum pH of the accumulation of heavy metal into cells were $20{\sim}37^{\circ}C$ and pH $6{\sim}8$, respectively. By increasing the concentration of each heavy metal-tolerant microorganism in the solution, the total amount of heavy metal accumulated was increased, whereas the amount of heavy metal accumulated per cell(mg, heavy metal/g, dry cells) was decreased. These results indicated that the amount of heavy metal accumulated was not proportional to the concentration of microorganisms.

• Journal of Sericultural and Entomological Science
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• v.48 no.1
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• pp.16-20
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• 2006

To shorten the labor cost for the production of the fungus, Paecilomyces tenuipies, uncocooning mutant hybrid silkworms as a host was used. The yield of P. tenuipies was reduced when Nd (uncocooning mutant) was used as a host because Nd was smaller than the hybrid Baegokjam that has been used as a typical host. To increase the host weight, Nd was crossed with Jam l23 or Jam 124, and resulted in not only greater weighter but also higher yield of P. tenuipies. The optimum temperature for rearing Nd hybrid silkworms was $3^{\circ}C$ higher than standard temperature of rearing silkworms to increase the naked pupation rate. The optimum time for the infection of P. tenuipies was 12 h at $28.5^{\circ}C$ and 95% R.H., when $1{\times}10^7spores/ml$ of P. tenuipies were sprayed on the surface of the silkworm. The conditions were applicable to both spring-rearing and autumn-rearing.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.100-100
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• 2010

토모그래피는 플라즈마 물리학뿐만 아니라 의료영상이나 천문학 등의 분야에서 오랫동안 이용되어 온 기법으로 직접 들여다 볼 수 없는 단면을 선적분된 데이터를 이용하여 국지적인 데이터를 재구성해내는 영상진단 방법이다. 플라즈마 물리학의 경우 공간적으로 검출기 배열을 균일하게 배치할 수 없으므로 토모그래피 기법에 균일화는 필수적이다. 이를 위해 본 연구에서는 Phillips-Tikhonov 균일화 방법을 사용하였다. Phillip-Tikhonov 균일화 방법은 인접한 픽셀 사이의 구배(gradient)를 최소화하는 방향으로 단면영상을 재구성하는 방식으로, 다른 토모그래피 알고리듬에 비해 훨씬 더 정확한 결과를 보여준다. 본 연구에서는 플라즈마의 공간분포 진단을 위하여 토모그래피 진단법과 부유탐침 진단법을 사용하였다. 플라즈마의 선적분된 방출광을 디지털카메라로 측정한 후 Phillips-Tikhonov 토모그래피 방법으로 재구성하여 플라즈마의 국지적인 공간분포를 알아내었다. 결과의 타당성을 확보하기 위해 부유탐침 진단결과와 비교 분석하여, 전자온도가 위치에 따라 일정한 상태에서 부유탐침을 통한 밀도분포와 토모그래피 진단법에 의한 플라즈마 방출광 세기의 공간분포가 거의 일치함을 확인할 수 있었다. 이를 통해 플라즈마의 국지적인 공간분포 진단을 위한 디지털카메라를 이용한 토모그래피 진단법의 타당성을 검증하였다.