• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.165-166
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• 2007

In these days $SF_6$ mixtures and alternative gas have been studied because of global warming and liquefying at low temperature and high pressure. At present work the breakdown characteristics of $SF_6/CF_4$ mixture in non-uniform field was performed. The experiments were carried out under positive and negative standard lightning impulse (SLT) voltages. The point-plane electrode was used with 3 mm gap distance in the test chamber. The $SF_6/CF_4$ mixture which contain 20% of $SF_6$ was compared with pure $SF_6$ and $CF_4$ gas. Experimental gas pressure ranged from 0.1 to 0.4 MPa. The breakdown voltage under negative SLI is higher than the breakdown voltage under positive voltage. And the breakdown voltage of $SF_6$ 20%, $CF_4$ 80% mixture is similar to that of pure $SF_6$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.227-228
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• 2007

Although many studies have been carried out about binary gas mixtures with $SF_6$, few studies were presented about breakdown characteristics of $SF_6/CF_4$ mixtures. At present study the breakdown characteristics of SFJCF4 mixtures in uniform field was performed. The experiments were carried out under AC and standard lightning impulse (SLI) voltages. The sphere-sphere electrode whose gap distance was 1 mm was used in a test chamber. $SF_6/CF_4$ mixtures contained from 0 to 100% $SF_6$ and the experimental gas pressure ranged from 0.1 to 0.4 MPa. The results show that addition of $SF_6$ to $CF_4$ increase AC and SLI breakdown voltages. Under AC voltages the breakdown voltages of each mixture were linearly increased according to the quantity of $SF_6$. However under SLI voltages the breakdown voltages of each mixture were similar.

• KEPCO Journal on Electric Power and Energy
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• 제3권1호
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• pp.41-47
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• 2017

After $SF_6$, which is being used in power equipment as an insulating material, is classified as one of the 6 major greenhouse gases, the maintenance and the refinement of used $SF_6$ started to get attention. In regard to this, KEPCO Research Institute (KEPRI) is developing $SF_6$ recovery and refinement technology starting with establishing a comprehensive $SF_6$ analysis system. With the analysis system, qualitative and quantitative analyses of the purity and the impurities of $SF_6$ before and after recovery, and before and after refinement have been carried out. The analysis system is comprised of GC-DID (Gas Chromatograph -Discharge Ionization Detector) for trace impurities analysis, GC-TCD (Thermal Conductivity Detector) for analyses of $SF_6$ purity and major impurities concentration from several hundred ppm up to percent range, GC-MSD (Mass Selective Detector) for analyses of impurities not included in standard gas, FT-IR (Fourier Transform-Infrared) Spectrometer for analysis of HF and $SO_2$, and moisture analyzer for analysis of moisture below 100 ppm. With this analysis system, complete analysis method of $SF_6$ has been established. This analysis system is being used in the maintenance of power equipment and the development of $SF_6$ recovery and refinement technologies. In this paper, the analysis results of four samples - gas and liquid phase $SF_6$ samples from a $SF_6$ refinement system before and after refinement are presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.470-471
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• 2007

환경친화적 가스절연기기의 개발을 위해 $SF_6/N_2$와 완충기체와의 혼합가스에 관한 연구가 주목받고 있다. 본 논문에서는 GIS 설계에 있어 기초가 되는 준평등전계 하에서의 가스 절연특성을 검토하기 위하여 순 SF6, N2, CO2 이들이 혼합된 2종 및 3종 혼합가스에 대해 가스압력 0.6MPa 이하에서 상용교류전압을 인가하여 실험에 의해 그 부분방전특성과 절연특성을 조사하였다. 특히 실용 전력기기의 경우 금속이물질 등의 혼입에 의해 기기 내에서 불평동전계가 형성되어 부분방전을 거쳐 절연파괴에 이르는 가능성이 있으므로 본 연구에서는 불평등전계하의 절연특성을 검토하였다. 실험 결과 SF6/N2 2종 혼합 가스에 비하여 SF6/N2/CO2 3종 혼합 가스의 교류 절연 특성이 향상됨을 확인하였으며 이상의 결과로부터 교류 절연 파괴 특성만을 고려하였을 경우 SF6/N2/CO2 3종 혼합 가스가 SF6 대체 혼합가스로써 타당성을 확인하였다.

• Biomolecules & Therapeutics
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• 제18권4호
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• pp.454-462
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• 2010

The present study investigated the neuroprotective effect of Carpinus tschonoskii MAX and its intracellular protective mechanism on 6-hydroxydopamine (6-OHDA)-induced oxidative damage in PC12 cells. We found that pretreatment of PC12 cells with C. tschonoskii extract significantly inhibited the cell death induced by 6-OHDA in a dose dependent manner. C. tschonoskii extract decreased 6-OHDA-induced apoptotic events such as chromatin condensation, DNA fragmentation, the decrease of Bcl-2/Bax ratio, caspase-3 activation and PARP cleavage. C. tschonoskii extract also reduced generation of 6-OHDA-induced reactive oxygen species and nitric oxide. Furthermore, C. tschonoskii extract up-regulated the myocyte enhancer factor 2 D (MEF2D), a critical transcription factor for neuronal survival, and Akt activity, whereas it inhibited the activity of ERK1/2 and JNK. The results suggest that C. tschonoskii extract decreases 6-OHDA-induced oxidative stress and could prevent PC12 cell apoptosis induced by 6-OHDA via the up-regulation of MEF2D and Akt activity, and thus may have application in developing therapeutic agents for Parkinson's disease.

• 대한화학회지
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• 제38권12호
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• pp.908-914
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• 1994

5원자 고리형 ${\beta}$-keto ester와 phenylalkylamine의 탈수축합으로 얻은 enamine A의 oxalyl화 및 물이나 메탄올 부가에 의하여 octahydro-2,3-dioxo-cyclopenta[b]-pyrrole-3a-carboxylate의 6a-hydroxy- 및 6a-methoxy-유도체(1~6)를 합성하였다. 헤테로 고리의 형성은 불안정한 N-acyliminium(B)체를 경유하여 일어나며, 안정한 부가체 C (1∼6)는 endo-ene형 pyrrolinium B에 친핵체를 부가하여 얻을 수 있었다.

• 한국응용과학기술학회지
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• 제17권3호
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• pp.174-177
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• 2000

The effect of a-sexithiophene(${\alpha}-6T$) layers on the light emitting diode (LED) were studied. The ${\alpha}-6T$ was used for a buffer layer in electroluminescent (EL) devices. Enhanced carrier (hole) injection and improved emission efficiency were observed. Carrier injection characteristics were investigated as a function of ${\alpha}-6T$ later thickness. The efficiency of the electroluminescence was proportional to the thickness of ${\alpha}-6T$ layer. The highest efficiency was observed 600A of ${\alpha}-6T$ later, which was about 1.5 times higher than that of device without ${\alpha}-6T$ later. The device with a-6T showed an operation voltage lowered by 2V. The ${\alpha}-6T$ layer can substitute hole blocking layer, and control charge injection properties.

• Journal of Electrochemical Science and Technology
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• 제7권4호
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• pp.245-250
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• 2016

The layered $Na_{0.6}Li_{0.6}[Mn_{0.72}Ni_{0.18}Co_{0.10}]O_2$ composite with well crystalized and high specific capacity is prepared by molten-salt method and using the substitution of Na for Li-ion battery. The effects of annealing temperature, time, Na contents, and electrochemical performance are investigated. In XRD analysis, the substitution of Na-ion resulted in the P2-$Na_{2/3}MO_2$ structure ($Na_{0.70}MO_{2.05}$), which co-exists in the $Na_{0.6}Li_{0.6}[Mn_{0.72}Ni_{0.18}Co_{0.10}]O_2$ composites. The discharge capacities of cathode materials exhibited $284mAhg^{-1}$ with higher initial coulombic efficiency.

• 대한화학회지
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• 제21권3호
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• pp.187-192
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• 1977

2-amino-5,6-dimethoxy-1,2,3,4-tetrahydronaphthalene hydrochloride를 2-nitro-3,4-dihydro-5,6-dimethoxy-(2H)-naphthalenone으로부터 합성하여서 Neber rearrangement로부터 얻은 2-amino-3,4-dihydro-5,6-dimethoxy-1(2H)-naphthalenone hydrochloride로부터 합성한 방법과 수득률 및 실업적인 조작을 비교 설명하였다.

• Journal of Korean Neurosurgical Society
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• 제43권4호
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• pp.190-193
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• 2008

Objective : Cancer-testis (CT) genes are considered promising candidates for immunotherapeutic approaches. The aim of this study was to investigate which CT genes should be targeted in immunotherapy for brain tumors. Methods : We investigated the expression of 6 CT genes (MAGE-E1, SOX-6, SCP-1, SSX-2, SSX-4, and HOMTES-85) using reverse-transcription polymerase chain reaction in 26 meningiomas and 32 other various brain tumor specimens, obtained from the patients during tumor surgery from 2000 to 2005. Results : The most frequently expressed CT genes of meningiomas were MAGE-E1, which were found in 22/26 (85%) meningioma samples, followed by SOX-6 (9/26 or 35%). Glioblastomas were most frequently expressed SOX-6 (6/7 or 86%), MAGE-E1 (5/7 or 71%), followed by SSX-2 (2/7 or 29%) and SCP-1 (1/7 or 14%). However, 4 astrocytomas, 3 anaplastic astrocytomas, and 3 oligodendroglial tumors only expressed MAGE-E1 and SOX-6. Schwannomas also expressed SOX-6 (5/6 or 83%), MAGE-E1 (4/6 or 67%), and SCP-1 (2/6 or 33%). Conclusion : The data presented here suggest that MAGE-E1 and SOX-6 genes are expressed in a high percentage of human central nervous system tumors, which implies the CT genes could be the potential targets of immunotherapy for human central nervous system tumors.