• 환경위생공학
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• 제10권3호
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• pp.16-28
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• 1995

Influences of capsaicin on the activities of cytochrome P45O of liver cell were studied in rats. Rats were provided food and water ad libitum and capsaicin and methylcellulose were gavaged for 6 days. Body weight gain and liver weight/body weight ratio, microsomal protein content and serum HDL- cholesterol content, the activity of cytochrome P450 and erythromycin demethylase, the activities of ethoxyresorufin and pentoxyresorufin O- dealkylase were determined. Capsaicin increased body weight gain but showed no significant changes on liver weight as compared with control group. Capsaicin increased the microsomal protein significantly but decreased the serum HDL- cholesterol. Capsaicin decreased the microsomal cytochrome P4SO significantly and did not show any influences on erythromycin demethylase ( cytochrome P45O III A ). Capsaicin increased the activity of pentoxyresorufin O- dealkylase ( cytochrome P45O II B) and decreased the activity of ethoxyresorufin O-dealkylase ( cytochrome P45O I A). It might be concluded that capsaicin reduced the microsomal cytochrome P45O and induced the CYP III and inhibited the CYP I A. It also might be concluded that capsaicin had no influence on CYP III A and decreased serum HDL- cholesterol. In these results capsaicin can not be used as an anti- atherosclerotic agent by increasing the CYP III A and HDL- cholesterol but it is considered that the more precise study on these theme is necessary.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.53-56
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• 2005

A Laboratory study was conducted to evaluate the kinetics of oxidation of trichloroethylene (TCE) in groundwater by potassium permanganate $(KMnO_4)$, Consumption of permanganate by TCE and aquifer materials was also evaluated to obtain an appropriate injection rate of $KMnO_4$. TCE degradation by $KMnO_4$ in the absence of aquifer material showed effective with pseudo-first order rate constant, $k_{obs}=1.8110^{-3}\;s^{-1}\;at\;KMnO_4=500mg/L$. TCE oxidation by $KMnO_4$ was found to be second order reaction and the rate constant, $k=0.65{\pm}0.08\;M^{-1}s^{-1}$, was independent of pH changes. $KMnO_4$ consumption rate by groundwater sampled from field site was not significant, indicating that groundwater containing negligible amount of dissolved organic matter does not have any influence on the $KMnO_4$ degradation. Meanwhile, aquifer materials from field site were actively reacted with permanganate, resulting in the significant consumption of $KMnO_4$. It might be attributed to the existence of metal oxides in aquifer materials, Based on the rate constants obtained from this study, appropriate injection rate of permanganate and TCE removal rate in groundwater could be estimated.

• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.372-376
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• 2022

Since the ZnO varistor is a semiconductor device, the internal thermal distribution during the varistor operation is recognized as an important factor in the performance and deterioration of the varistor. For an optimal varistor structure design, the thermal runaway phenomenon during the varistor operation was interpreted using the Comsol 5.2 analysis program by a finite element analysis. The maximum temperature of the center measured in the cross section of the ZnO varistor was confirmed to increase as the temperature moved from the lower electrode to the center towards the upper electrode up to 572.6 K. The electrodes are thinned so that the influence of the Schottky barrier is not great. The heat gradient balance is determined to be improved when the electrode of the hybrid form is introduced. The thickness, density, pore distribution, impurity uniformity, and particle size of the ZnO varistor are required, and it is determined that the pyrolysis gradient will be improved regardless of the electrode thickness. When these results are applied to design the ZnO varistor, the optimal structure of the ZnO varistor can be obtained.

• BMB Reports
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• 제35권4호
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• pp.377-383
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• 2002

Arsenic trioxide ($As_O_3$) was recently demonstrated to be an effective inducer of apoptosis in patients with relapsed acute promyelocytic leukemia (APL) as well as patients with APL in whom all-trans-retinoic acid and conventional chemotherapy failed. Chronic myelogenous leukemia cells are highly resistant to chemotherapeutic drugs. To determine if $As_O_3$ might be useful for the treatment of chronic myelogenous leukemia, we examined the ability of $As_O_3$ to induce apoptosis in K562 cells. In vitro cytotoxicity of $As_O_3$ was evaluated in K562 cells by a MTT assay: the $IC_50$ value for $As_O_3$ was determined to be $10\;{\mu}m$. When analyzed by agarose gel electorphoresis, the DNA fragments became evident after incubation of the cells with $20\;{\mu}m$ $As_O_3$ for 24 h. We also found morphological changes and chromatin condensation of the cells undergoing apoptosis. Activation of caspase-3 was observed 6 h after treatment with $20\;{\mu}m$ $As_O_3$ by a Western blot analysis. Next, we examined the MAP kinase-signaling pathway of $As_O_3$-induced apoptosis in K562 cells. $As_O_3$ at $10\;{\mu}m$ strongly induced the activation of p38, inhibited $As_O_3$ induced apoptotic cell death. These results suggest that $As_O_3$ is able to induce the apoptotic activity in K562 cells, and its apoptotic mechanism may be associated with the activation of p38.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3841-3848
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• 2022

The effect of modifiers on the optical features and radiation defying ability of the Eu³⁺ ions doped multi constituent glasses was examined. XRD has established the amorphous nature of the specimen. The presence of various functional/fundamental groups in the present glasses was analyzed through FTIR spectra. The physical, structural and elastic traits of the glasses were explored. The variation in the structural compactness of the glass structure according to the incorporated modifier was enlightened to describe their suitability for a better shielding media. For the examined glasses, the metallization criterion value varied in the range 0.613-0.692, indicating the non-metallic character of the glasses with possible nonlinear optical applications. The computed elastic moduli expose the Li-containing glass (BTLi:Eu) to be tightly packed and rigid, which is a requirement for a better shielding channel. Furthermore, the optical bandgap and the Urbach energy values are calculated based on the optical absorption spectra. The evaluated bonding parameters revealed the nature of the fabricated glasses covalent. In addition, we investigated the radiation attenuation attributes of the prepared Eu³⁺ ions doped multi constituent glasses using Phy-X software. We determined the linear attenuation coefficient (LAC) and reported the influence of the five oxides Li₂O₃, CaO, BaO, SrO, and ZnO on the LAC values. The LAC varied between 0.433 and 0.549 cm^-1 at 0.284 MeV. The 39B₂O₃-25TeO₂-15Li₂O₃-10Na₂O-10K₂O-1Eu₂O₃ glass has a much smaller LAC than the other glasses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1692-1695
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• 1999

The nonohmic characteristics of ZnO-$Pr_6O_{11}$-CoO-based ceramic varistor doped with $Dy_2O_3$ in the range $0.0\sim2.0mol%$ sintered at $1300^{\circ}C$ and $1350^{\circ}C$ were investigated. 98.5 ZnO-$0.5Pr_6O_{11}$-1.0CoO varistor sintered at $130^{\circ}C$ exhibited higher nonlinear coefficient of 36 than the established Pr-based varistor. The four-component-system varistor such as 96.5 ZnO-$0.5Pr_6O_{11}$-1.0CoO-$2.0Dy_2O_3$ exhibited very highly nonohmic characteristics, which has nonlinear coefficient of 53.9. 98.5ZnO-$0.5Pr_6O_{11}$-1.0CoO varistor sintered at $1350^{\circ}C$, in contrast with that of $1300^{\circ}C$, exhibited approximately ohmic characteristics but nonlinear coefficient of varistor doped with 0.5mol% $Dy_2O_3$ showed higher nonlinear coefficient of probably 35. Consequently, it can be confirmed that $Dy_2O_3$ acted as additive of improvement on nonlinear coefficient. It is estimated that $Dy_2O_3$ will be used as additive of improvement on nonlinear coefficient to develop a goof ZnO varistor.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.341-344
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• 2004

The superconducting properties of $YBa_2Cu_3O_x$ with different content impurities of PbO and $BaPbO_3$ were studied. When the PbO was used as an additive in $YBa_2Cu_3O_x$, although the melting point could be reduced, the superconductivity became poor. From the XRD pattern of the sintered mixture of $YBa_2Cu_3O_x$ and PbO it was known that there is a reaction between $YBa_2Cu_3O_x$ and PbO, and the product is $BaPbO_3$. In the process of the reaction the superconducting phase of $YBa_2Cu_3O_x$ was decreased and $BaPbO_3$ would be the main phase in the sample. Therefore, $BaPbO_3$ was chosen as the impurity additive for the comparative study. The single phase of $BaPbO_3$ was synthesized by the simple way from both mixtures of $BaCO_3$ and PbO, $BaCO_3$ and $PbO_2$. Different contents of $BaPbO_3$ (10%, 20%, 30%) were added in the $YBa_2Cu_3O_x$. By the Phase analysis in the XRD patterns it was proved that there was no reaction between $YBa_2Cu_3O_x$ and $BaPbO_3$. When $BaPbO_3$ was used as impurity in $YBa_2Cu_3O_x$ the superconductivity was much better than PbO as an impurity additive in $YBa_2Cu_3O_x$.

• 한국세라믹학회지
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• 제32권1호
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• pp.83-89
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• 1995

YBa2Cu3O7-$\delta$, Y2BaCuO5, and binary compounds in the Ba-Cu-O system with the nominal composition of Ba2CuO3, BaCuO2, Ba3Cu4O7, Ba3Cu5O8 were synthesized to investigate the heat evolutions and crystalline phases in the hydration reaction of orthorhombic YBa2Cu3O7-$\delta$ phase. The observed crystalline phases were YBa2Cu3O7-$\delta$, Y2BaCuO5, and BaCuO2, or Ba2Cu3O5＋x, and some amount of noncrystalline phase in the Ba-Cu system comounds. In contact with distilled water, YBa2Cu3O7-$\delta$ and Y2BaCuO5 did not have considerable heat liberation, but in the binary compounds of the Ba-Cu-O system, the amount of total heat liberation was increased with respect to the Cu content. It might be that the reaction of high temperature superconductor YBa2Cu3O7-$\delta$ with water and/or moisture originated from the unusual oxidation state of Cu ion and the presence of amorphous Ba-Cu oxide compound. The degradation of high Tc superconductor by moisture and water could be controlled by restricting the heterogeneous distribution of Tc comlposition and the formation of second phase, such as stable Y2BaCuO5, and the resulting unstable Ba-Cu oxide compound.

• 한국식품영양과학회지
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• 제19권6호
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• pp.612-616
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• 1990

전상이 일어나기 직전의 W/O형 에멀젼에는 W/O형 에멀젼과 섞여 O/W/O 형 에멀젼이 생성한다는 것을 알았다. 그래서 W/O형 에멀젼 중에 분산된 O/W/O형 분산의 정도를 평가하기 위한 목적으로 시료 에멀젼(수상 :물, 유상 TGCR을 함유한 올리브유)을 원추 평판형 회전 점도계를 사용하여 전단속도 1.92-384sec$^{-1}$(온도 25$\pm$0.1$^{\circ}C$)에서 점도를 측정하고 이 값을 Mooney의 점도식에 대입하여 이론치와 실측치의 차로부터 O/W/O형 분산의 정도를 평가했다. O/W/O형 에멀젼의 생성은 전상 직전의 시료에서 높았고, 유화제인 TGCR의 농도가 낮을수록 O/W/O형 에멀젼의 생성이 증가되는 경향이 나타났다. 이러한 사실로부터 W/O형 에멀젼이 전상 직전 부근에서 이론적으로 설명할 수 없는 고점도 현상이 전상직전의 O/W/O형 에멀젼의 생성에 의해서도 일어날 가능성이 있다고 사료된다.

• 전자공학회논문지 IE
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• 제49권2호
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• pp.1-8
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• 2012

단사정 구조의 순수 $ZrO_2$ 또는 5.35wt%의 $Y_2O_3$를 첨가한 정방정 구조의 $Y_2O_3(Y-TZP)$를 $Al_2O_3$에 첨가하여 그 기계적 특성 및 열충격 저항성을 연구하였다. $ZrO_2(m)$와 Y-TZP의 첨가량이 커짐에 따라 $Al_2O_3$의 소결 밀도가 증가하였다. 또한 Y-TZP의 첨가량이 증가함에 따라 비커스 경도도 증가하였고 첨가량 20wt%에서 최고값을 나타내었다. 시편의 경도는 소결 밀도에 의존함을 알 수 있었다. $ZrO_2(m)$나 Y-TZP 첨가량의 증가는 파괴인성을 향상시키는 결과를 얻을 수 있었다. 이러한 결과로 $Al_2O_3$의 경도는 $ZrO_2$의 transformation toughening 뿐 아니라 미세균열 강화에서도 얻어짐을 알 수 있었다. 단사정 구조의 순수 $ZrO_2$의 첨가는 $Al_2O_3-ZrO_2$의 열 충격 저항성을 향상시켰다. 결정입도는 $ZrO_2$의 첨가량이 증가함에 따라 커진다.