• Korean Journal of Microbiology
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• v.54 no.3
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• pp.200-207
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• 2018

At high salt concentration, glycine betaine is transported into Bacillus subtilis and growing rate of the cell is not suppressed. Also according to recent studies, cell growth is maintained normal growth rate at low temperature. Low temperature results in a stress response of Bacillus subtilis that is characterized by strong repression of major metabolic activities such as translation machinery and membrane transport. In this regards, genes showing cold sensitive phenotype are cold-induced DEAD box RNA helicases (ydbR, yqfR) and fatty acid desaturases (bkdR, des). Therefore to understand the effect of glycine betaine on cold growth of Bacillus subtilis, we investigated the effect of glycine betaine on growth rate of these deletion mutants showing cold sensitive phenotype. Glycine betaine strongly stimulated growth of wild type Bacillus subtilis JH642 and deletion mutants of ydbR and yqfR at $20^{\circ}C$ (190~686 min $T_d$ difference). On the other hands, glycine betaine does not show growth promoting effects on deletion mutants of bkdR, and des at cold conditions. Same cold protectant growth results were shown with the precursor choline instead of glycine betaine. We investigated the effects of detergents on the cell membrane in bkdR and des deficient strains associated with cell membrane. It was identified that bkdR deficient strain shows retarded growth with detergent such as Triton X-100 or N-lauryl sarcosine compared with wild type cell. Thus, it is possible that deletion mutation of bkdR modifies membrane structure and effects on transport of glycine betaine.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.44-56
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• 1998

Separate heat pipe exchanger is considered as the high thermal transportation equipment, because evaporator and condenser are separately positioned in the long distance. Its characteristics are that the working fluid is circulated naturally by the position height of two exchangers. But the operating characteristics are restricted by the temperature of hot and cold fluid, flow pattern and diameter of vapor line, etc. in this study, the vapor pressure and the minimum height of two exchangers are studied about the factors restricting the operating characteristics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.203-211
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• 1995

This study was conducted to know how low temperature response of rice varieties is available for breeding lines adapted to cold weather. Some agronomic characters related to cold tolerance were evaluated for 188 varieties including three varietal types of Japonica, Tongil, and Indica. Cold tolerance of Japonica and Indica type varieties varied in leaf discoloration, heading delay, reduction of culm length, panicle number, spikelet number, panicle exsertion, spikelet fertility, and phenotypic acceptability at maturity, while Tongil type varieties were susceptible in most agronomic characters. In leaf discoloration, most Japonica type varieties were highly tolerant, while Indica type varieties showed various responses from tolerant to susceptibility. Not significant difference among three varietal types was observed on reduction of panicle number and spikelet number due to low temperature.

• Vacuum Magazine
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• v.3 no.4
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• pp.14-18
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• 2016

In this article, we will summarize recent advances in ultrahigh vacuum (UHV) low-temperature scanning tunneling microscopy (STM) during the last decade. Leading STM groups have finished or are constructing UHV milli-Kelvin high magnetic field STM capable of a few tens of milli-Kelvin and ~ 10 tesla. Applications with UHV sub-Kelvin high magnetic STM have been increased since mid-2000's. Active research using UHV low temperature tuning fork atomic force microscopes and UHV photon low-temperature scanning tunneling microscopes will be introduced. Considering these advances of UHV low-temperature STM we will discuss next trend in STM in the near future.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.1
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• pp.11-17
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• 2007

The CCFLs, EEFLs and FFLs use mercury and the operating conditions are different at warm or cold temperature. At start of operation, there may exist a possibility of inhomogeneous operation of lamps or channels of FFL to the very low vapor pressure of mercury at low temperature. In this paper, an inverter with level control block (LCB) was developed to drive LCD backlight using FFL stably at low temperature range. The operation of FFL backlight at $-20^{\circ}C$ was successfully demonstrated by developing inverter with LCB under 130 Watt of power consumption.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.430-436
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• 1997

피동형 원자로에서 냉각수 펌프의 작동불능시나 계통 내의 강제 순환이 충분치 못할 경우, 냉각수와 분리된 비상 저온 고농축의 붕산수를 노심에 피동으로 주입시키고 자연 대류에 의한 잔열 제거가 이루어져야 한다. PIUS형 원자로나 SPWR형 원자로에서는 Honeycomb구조의 Density Lock을 사용하여 Shutdown 및 잔열 제거 기능을 수행하며 정상운전시에는Primary Coolant(고온, 저농축 붕산수)와 Pool Water(저온, 고농축 붕산수)를 분리하고 있다. Density Lock을 사용할 경우, 기동 운전이나 출력 변경과 같은 비정상 운전시 Density Lock을 통하여 노심으로 Pool Water가 유입될 수가 있다. 따라서 불필요한 Pool Water의 유입을 방지하고 피동형 원자로의 설계 개념을 만족시키며, 피동적으로 강제 순환으로부터 자연 순환으로의 경로를 열어 줄 수 있는 Hydraulic Valve에 대한 이론적 해석을 수행하여 실제 밸브를 제작하여 실험을 통해 이론과 비교하고 Valve의 특성곡선을 개발한다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.179-185
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• 1996

피동형 원자로에서 냉각수 펌프의 작동불능시나 계통 내의 강제 순환이 충분치 못할 경우, 냉각수와 분리된 비상저온 고농축의 붕산수를 노심에 피동으로 주입시키고 자연 대류에 의한 잔열 제거가 이루어져야 한다. PIUS형 원자로나 SPWR형 원자로에서는 Honeycomb구조의 Density Lock을 사용하여 Shutdown 및 잔열 제거 기능을 수행하며 정상운전시에는 Primary Coolant(고온, 저농축 붕산수)와 Pool Water(저온, 고농축 붕산수)를 분리하고 있다. Density Lock을 사용할 경우, 기동 운전이나 출력 변경과 같은 비정상 운전시 Density Lock을 통하여 노심으로 Pool Water가 유입될 수가 있다. 따라서 불필요한 Pool Water의 유입을 방지하고 피동형 원자로의 설계 개념을 만족시키며, 피동적으로 강제 순환으로부터 자연 순환으로의 경로를 열어 줄 수 있는 Hydrauric Valve에 대한 이론적 해석을 수행하여 실제 밸브를 제작하였다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.1-4
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• 1978

The change of soluble protein components in leaf discoloration of rice plant was investigated in the Growth Cabinet with various temperature conditions. The ratio between high molecular soluble protein and low molecular soluble protein was high under high temperature condition, while low under low temperature condition, and also lower in Indica type varieties than Japonica type variety.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.91-99
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• 2014

The objective of this study is to identify cold-tolerance genes in Brassica rapa. In order to acheive this goal, we analyzed a KBGP-24K oligo chip data [BrEMD (B. rapa EST and Microarray Database)] using B. rapa ssp. pekinensis inbred line 'Chiifu' under cold stress condition ($4^{\circ}C$). Among 23,929 unigenes of B. rapa, 417 genes (1.7%) were primarily identified as cold responsive genes that were expressed over 5-fold higher than those of wild type control, and then a gene which has unknown function and has full length sequence was selected. It was named BrCSR (B. rapa Cold Stress Resistance). BrCSR was transformed using expression vector pSL101 to confirm whether BrCSR can enhance cold tolerance in tobacco plants. $T_1$ transgenic tobacco plants expressing BrCSR were selected by PCR and Southern hybridization analyses, and the function of BrCSR was characterized by expression level analysis and phenotype observation under cold stress condition. The expression level of BrCSR in transgenic tobacco plants increased up to about two folds in quantitative real-time RT-PCR assay and this was very similar to Northern blot hybridization analysis. Analysis of phenotypic characteristics clearly elucidated that transgenic tobaccos expressing BrCSR were more cold tolerant than wild type control under $4^{\circ}C$ treatment. Based on these results, we conclude that the over-expression of BrCSR might be closely related to the enhancement of cold tolerance.

• Journal of Mushroom
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• v.10 no.4
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• pp.198-202
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• 2012

Recently, Pleurotus eryngii, King oyster mushroom, is main item of exportation in South Korea. For safe transportation to Europe and USA, it is necessary to elucidate suitable conditions of storage and treatment of post-harvest during long shipping period. For the selection of suitable package type, P. eryngii were stored at $0^{\circ}C$ and $4^{\circ}C$ after trimming and non-trimming package. Whole mushroom were packed with polypropylene anti-fog film about 400g. The weight loss ratio and elongation of pileus were increased with increasing storage time and temperature. There were little differences between trimming and non-trimming type in freshness at low temperature storage, $0^{\circ}C$ and $4^{\circ}C$. However, the freshness of non-trimming type P. eryngii at room temperature after low temperature storage is longer than that of trimming type. It was found that the optimum storage temperature and post-harvest treatment of P. eryngii were $4^{\circ}C$ and non-trimming type, respectively.