• The Korean Journal of Ceramics
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• 제1권1호
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• pp.1-6
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• 1995

Submicrometer, monosized ceramic powder of $Al_2TiO_5$$Al_2O_3$ ethanolic solutions. All particles produced by sol-gel-process were amprphous, monodispersed and with a narrow particle-size distribution. Compacts fired above $1300^{\circ}C$ formed aluminium titanate. Mullite formed first at $1480^{\circ}C$. After decomposition test at $1100^{\circ}C$, and cyclic thermal decomposition test at 750-1400-$750^{\circ}C$ for 100hrs., aluminium titanate was well stablized by composition with mullite.

• 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.

• 한국컴퓨터산업학회논문지
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• 제8권1호
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• pp.49-56
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• 2007

빔의 열적효과는 세포조직의 서로 다른 구성성분과 레이저 빔의 서로 다른 파장에서 다른결과를 나타내며 세포조직에서 온도증가는 먼저 응고가 이루어지고, 절단이나 탄화과정이 일어나며 $300^{\circ}$이상에서는 세포조직의 파괴에 의한 증발이 발생하게 된다. $CO_2$ 레이저는 최소한 조직손상으로 이러한 효과를 얻는데 최적이라고 보며 0.1mm의 최소한의 세포조직 깊이에서 일어나는 효과의 근본적인 장점은 생체조직이나 내장기관에 안정적이다. $CO_2$레이저사용에 있어서 단점은 무엇보다도 세포파괴에서 생성되는 입자들의 부품흡착 등으로 결과적으로 레이저의 출력감소가 일어나는데, 영 전압, 영 전류 스위칭 포워드 컨버터를 도입하여 기존의 하드 스위칭 포워드 컨버터에 있어서 Turn-off, on시 발생되는 스위칭 방식을, 적용함으로써 1차 측 스위칭 소자의 Turn-off, on시 영전압, 영전류 스위칭을 이루어 정밀도가 요구되는 산부인과용 $CO_2$ 연속 형 레이저의 고압출력 모듈에 따른 펄스 트랜스의 안정화에 필수적으로 기여하며, 레이저 출력과 안정화가 되도록 설계 및 제작한 결과, 기존제품보다 향상된 결과를 가져왔다. 추후 시스템적으로 보완을 하면 우수한 결과가 될 것으로 사려된다.