• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1609-1614
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• 2003

In this study, a practical holographic interferometric tomography system, which is instantaneous and non-contact for measuring three dimensional flow field, was developed. The system consists of holographic recording/reconstruction system, fringe analysis code and computational tomography code and it is developed with Gill environment for general users. The developed system was applied to three-dimensional natural convection from a discrete flush-mounted circular heat source on the bottom of a cubic enclosure. The heat source was located at the off-center of the bottom plate so that three-dimensional temperature field can be achieved. A set of multi-directional holographic interferograms was recorded by employing a double-reference beam, double-exposure holographic technique. Optical pathlength data were extracted from the recorded interferometric data and finally three dimensional temperature field inside the cube was reconstructed.

• Nuclear Engineering and Technology
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• 제38권6호
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• pp.483-488
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• 2006

Highly radioactive waste is placed in metal canisters embedded in dense clay termed buffer. The radioactive decay is associated with heat production, which causes degradation of the buffer and thereby time-dependent loss of its waste-isolating potential. The buffer is prepared by compacting air-dry smectite clay powder and is initially not fully water saturated. The evolution of the buffer starts with slow wetting by uptake of water from the surrounding rock followed by a long period of exposure to heat, pressure from the rock and chemical reactants. It can be described by conceptual and theoretical models describing processes related to temperature (T), hydraulic (H), mechanical (M) and chemical performance (C). For temperatures below 90 C more than 75 % of the smectite will be preserved for 100 000 years but cementation may reduce the excellent performance of the buffer to a yet not known extention.

• 열처리공학회지
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• 제13권1호
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• pp.16-20
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• 2000

There have been little reports on the degradation of medium-carbon steel tubes served at high temperature for a long period. The purpose of this research was to provide the information of the proper replacement span of the tubes with the new ones. We investigated the medium-carbon steel tubes which were used at petrochemical plant for about 50,000 hrs to examine their mechanical properties and microstructures. Experimental results showed that the tubes satisfied the specification of ASTM despite such a long period of service, but mechanical properties, especially charpy impact values, were reduced. It concludes that the tubes on service at the plants needs a periodical inspection.

• 한국세라믹학회지
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• 제48권4호
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• pp.328-333
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• 2011

The influence of Al-doped ZnO (AZO) thin films degraded under high temperature and damp heat on the performance deterioration of Cu(In,Ga)$Se_2$ (CIGS) solar cells was investigated. CIGS solar cells with AZO/CdS/CIGS/Mo structure were prepared on glass substrate and exposed to high temperature ($85^{\circ}C$) and damp heat ($85^{\circ}C$/85% RH) for 1000 h. As-prepared CIGS solar cells had 64.91% in fill factor (FF) and 12.04% in conversion efficiency. After exposed to high temperature, CIGS solar cell had 59.14% in FF and 9.78% in efficiency, while after exposed to damp heat, it had 54.00% in FF and 8.78% in efficiency. AZO thin films in the deteriorated CIGS solar cells showed increases in resistivity up to 3.1 times and 4.4 times compared to their initial resistivity after 1000 h of high temperature and damp heat exposure, respectively. These results can be explained by the decreases in carrier concentration and mobility due to diffusion or adsorption of oxygen and moisture in AZO thin films. It can be inferred that decreases in FF and conversion efficiency were caused by an increase in series resistance, which resulted from an increase in resistivity of AZO thin films degraded under high temperature and damp heat.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.965-970
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• 2005

In our previous study [14], we found that heat-shock exposure did not stimulate the neutral trehalase activity in Sacchromyces cerevisiae KNU5377, but did in ATCC24858. Consequently, the trehalose content in KNU5377 became 2.6 times higher than that in ATCC24858. Because trehalose has been shown to stabilize the structure and function of some macromolecules, the present work was focused to elucidate the relationship between trehalose content of these strains and thermal stabilities of whole cells, through differential scanning calorimetry (DSC), and to predict critical targets calculated from the hyperthermic cell killing rates. These analyses showed that the prominent DSC transition of both strains gave identical $T_m$ (transition temperature) values in exponentially growing cells, and that the $T_m$ values of critical targets was about $3^{\circ}C$ higher in KNU5377 than in ATCC24858. Both heat-shocked KNU5377 and ATCC24858 cells displayed similar shifts in their DSC transition profiles. On the other hand, the $T_m$ value of the critical target of KNU5377 was decreased by $2.1^{\circ}C$, which was still higher than ATCC24858 showing no changes. In view of these results, the intrinsic thermotolerance of KNU5377 did not appear to result from the stability of entire cellular components, but rather possibly from that of particular macromolecules, including critical targets, even though it should be investigated in more details. Although the trehalose levels in heat-shocked cells are significantly different, as described in our previous study [14], the overall pattern of thermal stabilities and their predicted critical targets in two heat-shocked strains seemed to be identical. These data suggest that the trehalose levels examined before and after heat shock of exponentially growing cells are not closely correlated with the stabilities of whole cells and/or critical targets in both yeast strains.

• Journal of Microbiology
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• 제39권3호
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• pp.162-167
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• 2001

Methylovorus sp. strain SS1 DSM 11726 was found to grow continuously when it was transferred from 30$\^{C}$ to 40$\^{C}$ and 43$\^{C}$. A shift in growth temperature from 30$\^{C}$ to 45$\^{C}$, 47$\^{C}$ and 50$\^{C}$ reduced the viability of the cell population by more than 10$^2$, 10$^3$and 10$\^$5/ folds, respectively, after 1h cultivation. Cells transferred to 47$\^{C}$ and 50$\^{C}$ after preincubation for 15 min at 43$\^{C}$, however, exhibited 10-fold increase in viability. It was found that incubation for 15 min at 40$\^{C}$ of Methylovorus sp. strain SSl grown at 30$\^{C}$ was sufficient to accelerate the synthesis of a specific subset of proteins. The major heat shock proteins had apparent molecular masses of 90, 70, 66, 60, and 58 kDA. The 60 and 58 kDa proteins were found to cross-react with the antiserum raised against GroEL protein. The heat shock response persisted for over 1h. The shock proteins were stable for 90 min in the cell. Exposure of the cells to methanol induced proteins identical to the heat shock proteins. Addition of ethanol induced a unique protein with a molecular mass of about 40 kDa in addition to the heat-induced proteins. The proteins induced in paraquat-treated cells were different from the heat shock proteins, except the 70 and 60 kDa proteins.

• 한국가스학회지
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• 제2권1호
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• pp.1-6
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• 1998

전력을 적재 소모하는 (300 mW 이하) 촉매가스센서가 개발되었고, 천연가스에 열용량을 측정하기 위해 컴퓨터로 작동되는 샘플링 시스템에 사용되었다. 가스의 열용량은 촉매자스센서가 감지되는 연소가스에 노출되었을 때 발생된 에너지에 비례된다. 36.30 - 39.88 $MJ/m^3$ 범위의 정격 열용량을 갖는 천연가스의 열용량은 약 $1\%$ 에러 내에서 측정되었다. 각 가스들은 센서의 온도에 대하여 약간씩 다른 감응곡선을 갖고 있다. 따라서 한 온도에서 모든 감응이 같을 수는 없다. 작동 온도는 측정장치의 전 성능에 영향을 미치기 때문에 교정과정에서 최적의 작동 온도를 찾는 것은 중요하다.

• KSBB Journal
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• 제18권4호
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• pp.294-300
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• 2003

본 연구에서는 L. fermentum KLB12을 열 전처리 함으로서 제제화 과정 동안 거치게 되는 열 스트레스에 대한 내성이 증진됨을 확인하고, 최적의 열 전처리 조건을 수행하였다. 또한 열 전처리 뿐만 아니라, 저온과 열 전처리 조건에도 열 스트레스에 대한 간섭 효과를 확인하였다. 그리고 내성 증진에 신규 단백질 합성이 필요함을 확인하였으며 나아가, 2-D electrophoresis를 통하여 7개의 신규 단백질을 확인하였다. 따라서 이 균주를 제제화하기 위한 방법으로 열 전처리를 이용할 경우 생균력 유지에 큰 효과를 얻을 수 있다고 사료된다.

• 한국패류학회지
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• 제29권3호
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• pp.181-187
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• 2013

In order to investigate environmental stress inducible genes in abalone, we analyzed differentially expressed transcripts from a Pacific abalone, Haliotis discus hannai, after exposure to heat-, cold- or hyposalinity-shock by suppression subtractive hybridization (SSH) method. 1,074 unique sequences from SSH libraries were composed to 115 clusters and 986 singletons, the overall redundancy of the library was 16.3%. From the BLAST search, of the 1,316 ESTs, 998 ESTs (75.8%) were identified as known genes, but 318 clones (24.2%) did not match to any previously described genes. From the comparison results of ESTs pattern of three SSH cDNA libraries, the most abundant EST was different in each SSH library: small heat shock protein p26 (sHSP26) in heat-shock, trypsinogen 2 in cold-shock, and actin in hyposalinity SSH cDNA library. Based on sequence similarities, several response-to-stress genes such as heat shock proteins (HSPs) were identified commonly from the abalone SSH libraries. HSP70 gene was induced by environmental stress regardless of temperature-shock or salinity-stress, while the increase of sHSP26 mRNA expression was not detected in cold-shock but in heat-shock condition. These results suggest that the suppression subtractive hybridization method is an efficient way to isolate differentially expressed gene from the invertebrate environmental stress-response transcriptome.

• Journal of Ginseng Research
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• 제43권1호
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• pp.143-153
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• 2019

Background: Ginseng is one of the well-known medicinal plants, exhibiting diverse medicinal effects. Its roots possess anticancer and antiaging properties and are being used in the medical systems of East Asian countries. It is grown in low-light and low-temperature conditions, and its growth is strongly inhibited at temperatures above $25^{\circ}C$. However, the molecular responses of ginseng to heat stress are currently poorly understood, especially at the protein level. Methods: We used a shotgun proteomics approach to investigate the effect of heat stress on ginseng leaves. We monitored their photosynthetic efficiency to confirm physiological responses to a high-temperature stress. Results: The results showed a reduction in photosynthetic efficiency on heat treatment ($35^{\circ}C$) starting at 48 h. Label-free quantitative proteome analysis led to the identification of 3,332 proteins, of which 847 were differentially modulated in response to heat stress. The MapMan analysis showed that the proteins with increased abundance were mainly associated with antioxidant and translation-regulating activities, whereas the proteins related to the receptor and structural-binding activities exhibited decreased abundance. Several other proteins including chaperones, G-proteins, calcium-signaling proteins, transcription factors, and transfer/carrier proteins were specifically downregulated. Conclusion: These results increase our understanding of heat stress responses in the leaves of ginseng at the protein level, for the first time providing a resource for the scientific community.