• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.120-123
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• 2019

The effect of surface plasmon on ZTO thin films was investigated. The phenomenon of depletion occurring in the interface of the ZTO thin film created a potential barrier and the dielectric layer of the depletion formed a non-mass particle called plasmon. ZTO thin film represents n-type semiconductor features, and surface current by plasma has been able to obtain the effect of improving electrical efficiency as a result of high current at positive voltage and low current at negative voltage. It can be seen that the reduction of electric charge due to recombination of electronic hole pairs by heat treatment of compound semiconductors induces higher surface current in semiconductor devices.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.267-273
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• 2007

A depletion-mode MOSFET has been analyzed to evaluate its electrical behavior using a novel 3-D numerical simulation package. The characterizing analysis of the BC MOSFET was performed through short-channel narrow-channel and small-geometry effects that are investigated, in detail, in terms of the threshold voltage. The DIBL effect becomes significant for a short-channel device with a channel length of $<\;3({\mu}m)$. For narrow-channel devices the variation of the threshold voltage was sharp for $<4({\mu}m)$ due to the strong narrow-channel effect. In the case of small-geometry devices, the shift of the threshold voltage was less sensitive due to the combination of the DIBL and substrate bias effects, as compared with that observed from the short-channel and narrow-channel devices. The characterizing analysis of the narrow-channel and small-geometry devices, especially with channel width of $<\;4({\mu}m)$ and channel area of $<\;4{\times}4({\mu}m^2)$ respectively, can be accurately performed only from a 3-D numerical simulation due to their sharp variations in threshold voltages.

• 약학회지
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• 제49권4호
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• pp.355-364
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• 2005

A neurotoxin, 6-hydroxydopamine (6-OHDA) has long been used to form a Parkinson's disease (PD) model by inducing the lesion in catecholaminergic pathways, particularly the nigrostriatal dopamine (DA) pathway. Whereas l-deprenyl, a selective inhibitor of monoamine oxidase (MAO) type B, is now widely used in the treatment of PD, the precise action mechanism of the drug remains elusive. In this study, we investigated whether l-deprenyl shows protective effect against the DA depletion induced by 6-OHDA in rat brain, and against 6-OHDA-induced neurotoxicity and oxidative stress in catecholaminergic neuroblastoma SH-SY5Y cells that are known to lack MAO-B activity. Pretreatment of l-deprenyl significantly enhanced the striatal DA, 3,4-dihydroxyphenylacetic acid, homovanilic acid, and 3-methoxytyramine levels compared to the untreated 6-OHDA-lesioned rat, indicating that l-deprenyl pretreatment prevents 6-OHDA-induced depletion of not only striatal dopamine but also its metabolites. Treatment of 6-OHDA for 24hrs decreased the cell viability and increase the generation of ROS in dose-dependent manners. We further investigated whether caspase activity is involved in the action of l-deprenyl. Treatment of l-deprenyl $(0.1\~100{\mu}M)$ did not produce any changes in 6-OHDA-induced cleavage of poly (ADP-ridose) polymerase in SH-SY5Y cells. Our results suggest that the neuroprotective effect of l-deprenyl against 6-OHDA is due to its increased scavenger activity, but independent of inhibition of MAO-B or caspase-3 activation.

• Journal of Acupuncture Research
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• 제18권4호
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• pp.143-151
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• 2001

Objective : This study was undertaken to determine whether Scutellaria balicalensis Georgi (SbG) extract exerts the protective effect against oxidant-induced alterations in organic cation transport in the renal proximal tubule. Methods : Organic cation transport was estimated by examining alterations in tetraethylammon - ium(TEA) uptake in rabbit renal cortical slices. The slices were treated with 0.2 mM tBHP for 60 min at $37^{\circ}C$. tBHP caused an inhibition in TEA uptake by renal cortical slices. Such an effect was accompanied by depressed Na+-K+-ATPase activity and ATP depletion. tBHP also induced a significant increase in LDH release. Results : SbG prevented tBHP-induced inhibition of TEA uptake in a dose-dependent manner at the concentration ranges of 0.05-0.1%. tBHP-induced inhibition of Na+-K+-ATPase activity and ATP depletion were significantly prevented by 0.05% SbG. tBHP-induced LDH release also was blocked by SbG. tBHP caused a significant increase in lipid peroxidation and its effect was prevented by SbG. Conclusion : These results suggest that SbG prevents oxidant-induced alterations in organic cation transport in rabbit renal cortical slices. Such protective effects of SbG may be attributed to inhibition of peroxidation of membrane lipid.

• 방사성폐기물학회지
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• 제9권4호
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• pp.237-245
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• 2011

후쿠시마 사고 이후 사용후핵연료 저장시설 안전성 재검증 필요성이 증대되고 있는 가운데, 재검증 결과의 신뢰성 향상을 위해 열부하 평가결과의 정확도 향상이 요구되고 있다. 이를 위한 기초연구로 본 연구에서는 상대적으로 중요성이 저평가되었던, 저장시나리오, 연소조건 관련 인자와 같이 붕괴열 및 열부하 평가 영향인자를 도출하고, 고리 4호기를 대상으로 ORIGEN2 코드를 이용해 그 효과를 평가하였다. 대표 저장시나리오에 대한 열부하 평가 결과, 최후 방출 핵연료의 붕괴열은 시나리오에 따라 전체 열부하의 최대 80.42%를 차지해 저장시설 열부하에 지배적인 영향을 미침이 확인되었다. 또한 연소조건 인자로 선택된 축 방향 연소 효과, 연소이력, 비출력 효과에 대한 민감도 분석 수행 결과, 냉각기간이 짧을수록 각 인자의 붕괴열에 대한 영향이 커지는 것으로 확인되었다. 각 인자별로는 비출력, 연소이력, 축 방향 연소 효과의 순으로 붕괴열에 대한 영향력이 컸으며, 특히 비출력의 경우 방출 직후 평균값의 0.34에서 1.66배, 방출 1년 후에는 평균 대비 0.55에서 1.37배까지 붕괴열 변화를 초래함이 확인되었다. 즉, 저장시설의 열부하 평가와 같이 냉각기간이 짧은 핵연료에 대한 해석 시 비출력, 연소이력과 같은 연소조건인자가 해석결과에 매우 큰 차이를 초래할 수 있으므로, 해석결과의 정확도 향상을 위해 기존 해석자의 공학적 판단에 의거한 임의 인자 대표성 핵연료 선택방식 대신 실제 운전 데이터의 적용 등이 필요할 것으로 보인다. 본 연구 결과는 향후 열부하 해석 결과의 정확도 향상 및 불확실도 평가를 위한 기초자료로 활용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2129-2140
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• 2017

Silibinin is the major active component of silymarin, extracted from the medicinal plant Silybum marianum. Silibinin has potent antibacterial activity; however, the exact mechanism underlying its activity has not been elucidated. Here, we investigated the novel mechanism of silibinin against Escherichia coli. Time-kill kinetic assay showed that silibinin possess a bactericidal effect at minimal inhibitory concentration (MIC) and higher concentrations (2-and 4-fold MIC). At the membrane, depolarization and increased intracellular $Ca^{2+}$ levels were observed, considered as characteristics of bacterial apoptosis. Additionally, cells treated with MIC and higher concentrations showed apoptotic features like DNA fragmentation, phosphatidylserine exposure, and caspase-like protein expression. Generally, apoptotic death is closely related with ROS generation; however, silibinin did not induce ROS generation but acted as a scavenger of intracellular ROS. These results indicate that silibinin dose-dependently induces bacterial apoptosis-like death, which was affected by ROS depletion, suggesting that silibinin is a potential candidate for controlling bacteria.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.104-108
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• 2016

To research the correlation between oxygen vacancy and the electrical characteristics of ZTO, which is made by using a target mixed ZnO:SnO₂=1:1, the ZnO, SnO₂ and ZTO were analyzed by PL, XPS, XRD patterns and electrical properties. It was compared with the electron orbital spectra of O 1s in accordance with the electrical characteristics of ZnO, SnO₂ and ZTO. The electrical characteristics of ZTO were improved by increasing the annealing temperatures, due to the high degree of crystal structures at a high temperature, and the physical properties of ZTO was similar to that of ZnO. The amorphous structure of SnO₂ was increased with increasing the temperature. The Schottky contact of oxide semiconductors was formed using the depletion region, which is increased by the electron-hole combination due to the annealing processes. ZnO showed the Ohmic contact in spite of a high annealing temperature, but SnO₂ and ZTO had Schottky contact. As such, it was confirmed that the electrical properties of ZTO are affected by the molecules of SnO₂.

• 설비공학논문집
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• 제14권4호
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• pp.332-340
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• 2002

In these days, environmental concerns have been increased throughout the industry and community worldwide. To prevent the ozone depletion, ozone depletion potential of a refrigerant must be zero. Simultaneously, a refrigerant with low GWP (global warming potential) is very demanding to induce green house effect. Chlorine-free HFC-l34a is a refrigerant widely used for automotive air-conditioning system because its destruction potential is ecologically zero. Although HFC-l34a has no ozone depletion potential, its global warming potential is so high that it is not considered as a perfect alternative refrigerant that is acceptable for long-term use. In this paper, experimental measurement has been carried out to analyze the performance characteristics of automotive air-conditioning system using HFC-152a, which has low GWP and zero ODP. Also mixed refrigerant that is composed of HFC-152a and $CF_3$ was applied to investigate an alternative possibility for the automotive airconditioning system. As a result of this study, we could draw following conclusions; With respect to the variation of the rotational speed of compressor, outside air temperature and flow rate, the heat amount of evaporator and compressor and performance coefficient was varied.

• 대한전자공학회논문지SD
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• 제46권12호
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• pp.10-17
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• 2009

Double-Gate MOSFET 구조를 사용한 Nano-Electro-Mechanical MOSFET (NEMFET)는 게이트 길이가 짧아지면서 나타나는 단채널 현상을 효과적으로 제어하는 새로운 구조의 차세대 소자이다. 특히 공핍형 Double-gate NEMFET (Dep-DGNEMFET)은 차단 상태에서 얇은 산화막을 가지므로 subthreshold 전류가 효과적으로 제어된다. 이러한 Dep-DGNEMFET 특성에 대한 해석적 수식을 유도하고 소자 구조가 변화하는 경우의 특성 변화를 분석하였다. 또한 ITRS (International Technology Roadmap for Semiconductors) 전류 기준값을 만족시키기 위하여 Dep-DGNEMFET 소자 구조를 최적화 하였다.

• International Journal of Air-Conditioning and Refrigeration
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• 제11권3호
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• pp.140-149
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• 2003

In these days, environmental concerns have been increased throughout the industry and community worldwide. To prevent the ozone depletion, ozone depletion potential of a refrigerant must be zero. Simultaneously, a refrigerant with low GWP (global warming potential) is very demanding to reduce green house effect. Chlorine-free HFC-l34a is a refrigerant widely used for automotive air-conditioning system because its destruction potential is ecologically zero. Although HFC-l34a has no ozone depletion potential, its global warming potential is so high that it is not considered as a perfect alternative refrigerant that is acceptable for long-term use. In this paper, experimental measurement has been carried out to analyze the performance characteristics of automotive air-conditioning system using HFC-152a, which has low GWP and zero ODP. Also mixed refrigerant that is composed of HFC-152a and $CF_3$ was applied to investigate an alternative possibility for the automotive air-conditioning system. As a result of this study, we could draw following conclusions; With respect to the variation of the rotational speed of compressor, outside air temperature and flow rate, the heat amount of evaporator and compressor and performance coefficient was varied.