• 열처리공학회지
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• 제24권1호
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• pp.31-36
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• 2011

$TiO_2$ films were deposited on a glass substrate with RF magnetron sputtering and then surface of $TiO_2$ films were electron beam irradiated in a vacuum condition to investigate the effect of electron bombardment on the thin film crystallization, surface roughness and gas sensitivity for hydrogen. $TiO_2$ films that electron beam irradiated at 450eV were amorphous phase, while the films irradiated at 900 eV show the anatase (101) diffraction peak in XRD pattern. AFM measurements show that the roughness is depend on the electron irradiation energy. As increase the hydrogen gas concentration and operation temperature, the gas sensitivity of $TiO_2$ and $TiO_2$/ZnO films is increased proportionally and $TiO_2$ films that electron beam irradiated at 900 eV show the higher sensitivity than the films were irradiated at 450eV. From the XRD pattern and AFM observation, it is supposed that the crystallization and rough surface promote the hydrogen gas sensitivity of $TiO_2$ films.

• 한국축산식품학회지
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• 제33권4호
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• pp.481-486
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• 2013

This study evaluates the effects of fat contents on the thermal resistance, antibiotic sensitivity, and Caco-2 cell invasion of Listeria monocytogenes. Ten strain mixture of L. monocytogenes in milk (0, 1, and 4% fat) and pork sausage patties (10, 20, and 30% fat) were exposed to $63^{\circ}C$. To evaluate effects of fat on the antibiotic sensitivity of L. monocytogenes, the L. monocytogenes strains NCCP10811 (most antibiotic resistant to streptomycin) and NCCP10943 (most antibiotic sensitive to streptomycin) were exposed to different fat contents in milk and pork sausage patties, and L. monocytogenes from the foods were used for antibiotic sensitivity assays. The most invasive L. monocytogenes strains (NCCP10943) was exposed to different fat contents in milk or pork sausage patties, and L. monocytogenes from the foods were used for the Caco-2 cell invasion assays. The reductions of L. monocytogenes populations were not generally influenced by fat contents. The L. monocytogenes subjected to milk fat had increased sensitivities (p<0.05) due to some antibiotics. In addition, Caco-2 cell invasion efficiency of L. monocytogenes NCCP10943 increased (p<0.05) as fat contents increased. These results indicated that higher fat contents may be related to L. monocytogenes invasions and heat resistances in pork sausage patties, but the relationship between fat and antibiotic sensitivity varied according to antibiotics, strains, and fat contents.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1753-1755
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• 1999

$LaCoO_3$ thick-film sensors were fabricated on alumina substrate by screen printing method. The sensitivity for gases was investigated by varying the heat treatment temperature of the films. X-Ray Diffractions and SEM photographs were used to examine their structural properties. The sensitivity of $LaCoO_3$ thick-film for CO gas was much better than for $C_4H_{10}$, $NH_3$ and NO gases. The best condition of heat treatment was $800^{\circ}C$ and the optimal operating temperature of $LaCoO_3$ thick-film for the highest sensitivity was $150^{\circ}C$. Sensitivities of the $LaCoO_3$ thick-film at 500ppm and l000ppm for CO gas were 72% and 95%, respectively.

• 한국연소학회지
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• 제18권4호
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• pp.1-11
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• 2013

The oxy-fuel combustion is $CO_2$ capture technology that uses mixture of pure $O_2$ and recirculated exhaust as oxidizer. Currently some Oxy-fuel power plants demonstration project is underway in worldwide. Meanwhile research project for converting 125 MWe Young-Dong power plant to 100 MWe oxy-fuel power plants is progress. In this paper, 1 D process analytical approach was applied for conducting process design and operating parameters sensitivity analysis for oxy-fuel combustion of Young-Dong power plant. As a result, appropriate gas recirculation rates was 74.3% that in order to maintain normal rating superheater, reheater steam temperature and boiler heat transfer patterns. And boiler efficiency 85.0%, CPU inlet $CO_2$ mole concentration 71.34% was predicted for retrofitted boiler. The oxygen concentration in the secondary recycle gas is predicted as 27.1%. Meanwhile the oxygen concentration 22.4% and moisture concentration 5.3% predicted for primary recycle gas. As the primary and secondary gas recirculation increases, then heat absorption of the reheater is tends to increases whereas superheater side is decreased, and also the efficiency is tends to decrease, according to results of sensitivity analysis for operating parameters. In addition, the ambient air ingression have a tendency to lead to decline of efficiency for boiler as well as decline of $CO_2$ purity of CPU inlet.

• BMB Reports
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• 제45권5호
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• pp.299-304
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• 2012

The ubiquitin-proteasome system is a major proteolytic system for nonlysosomal degradation of cellular proteins. Here, we investigated the response of mouse embryonic stem (ES) cells under proteotoxic stress. Proteasome inhibitors induced expression of heat shock protein 70 (HSP70) in a concentration- and time-dependent manner, and also induced apoptosis of ES cells. Importantly, more apoptotic cells were observed in ES cells compared with other somatic cells. To understand this phenomenon, we further investigated the expression of HSP70 and pluripotent cell markers. HSP70 expression was more significantly increased in somatic cells than in ES cells, and expression levels of pluripotent cell markers such as Oct4 and Nanog were decreased in ES cells. These results suggest that higher sensitivity of ES cells to proteotoxic stress may be related with lower capacity of HSP70 expression and decreased pluripotent cell marker expression, which is essential for the survival of ES cells.

• 열처리공학회지
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• 제24권3호
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• pp.140-143
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• 2011

In this work, Ga doped ZnO (GZO) films were prepared by radio frequency (RF) magnetron sputtering without intentional substrate heating on glass substrate and then the effect of the intense electron irradiation on structural and electrical properties and the NOx gas sensitivity were investigated. Although as deposited GZO films showed a diffraction peak for ZnO (002) in the XRD pattern, GZO films that electron irradiated at electron energy of 900 eV showed the higher intense diffraction peaks than that of the as deposited GZO films. The electrical property of the films are also influenced with electron's energy. As deposited GZO films showed the three times higher resistivity than that of the films irradiated at 900 eV In addition, the sensitivity for NOx gas is also increased with electron irradiation energy and the film sensor showed the proportionally increased gas sensitivity with NOx concentration. This approach is promising in gaining improvement in the performance of thin film gas sensors used for the detection of hazard gas phase.

• 대한금속재료학회지
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• 제48권4호
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• pp.342-346
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• 2010

Pd nanoparticles (NPs) were successfully functionalizedon the surfaces of single-walled carbon nanotubes (SWNTs) by dendrimer-mediated synthesis. The hydrogen sensing properties of the Pd NPs functionalized SWNTs were investigated. Pd NPs-dendrimer-SWNTs sensors show much better speedsand superior recovery rates but lower sensitivity compared to Pd NPs-functionalized SWNTs directly fabricated due to the existence of dendrimers. Pyrolysis of the dendrimers by heat treatment resulted in a fast response time and high sensitivity owing to the reduced length of the dendrimers. These results demonstrate that the heat treatment of dendrimers in Pd NPs-dendrimer-SWNTs sensors can enable significant electrical conductance modulation upon exposure to extremely low concentrations (10 ppm) of hydrogen gas ($H_2$) in air.

• 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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.799-804
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• 2002

This paper is mainly Intended to show an effect of foundation depth on heat of hydration in mass concrete. From the analysis, it was found that the foundation depth which is not affected by the heat conduction is more than 5 m. But this study shows that, an optimum foundation depth for the FEM analysis for heat of hydration in mass concrete is approximately 1 m from this study. And in order to study tile significance of various parameters, a sensitivity analysis of heat transfer in mass concrete is performed and the amount of heat liberated at complete hydration of unit weight of cement and the reaction velocity of hydration are the most sensitive parameters factors of other various parameters.

• 대한수의학회지
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• 제11권2호
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• pp.137-140
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• 1971

Survival and thermal inactivation after heat treatment at $143^{\circ}F$ were observed among 27 strains of coliform bacteria isolated from dairy cattle. The results obtained were as follows. 1. The obvious differences in heat-sensitivity were observed among the strains tested. 2. No strain was found resistant to the heat treatment of $143^{\circ}F$ for 30 minutes. 3. A marked effect of density of coliform bacteria on the survival after the heat treatment was observed. As the density of coliform bacteria was increased, the rate of survival was increased markedly regardless of the length of heat treatment.