• 세라미스트
• /
• 제21권2호
• /
• pp.49-58
• /
• 2018

Metal oxide based materials have been widely used to fields of electrochemical applications. Recently, various type of defects from microstructures of metal oxides and their nanocomposites have been raised as the important material design factors for realizing highly improved electrochemical properties. Previous experimental and theoretical works have suggested that controlling the reaction activity and kinetics of the key electrochemical reactions by activated interfaces originating from the defect sites can play an important role in achieving the robust energy storage and conversion. Therefore, this paper focuses on the role of defect-controlled metal oxide materials such as doping, edge-sites, grain boundaries and nano-sized pores for the high performances in energy storage devices and electrocatalysts. The research approaches demonstrated here could offer a possible route to obtain noble ideas for designing the metal oxide materials for the energy storage and conversion applications.

• Journal of Electrochemical Science and Technology
• /
• 제7권3호
• /
• pp.199-205
• /
• 2016

We present the electrochemical performance of electric double layer capacitors (EDLCs) assembled with pyrrolidinium (Pyr)-based ionic liquid electrolytes at 55 ℃. Cations with various alkyl chain lengths were employed in Pyr-based ionic liquids to investigate the effect of cation structure on the cycling stability of EDLCs. The EDLCs exhibited initial specific capacitances ranging from 122.4 to 131.6 F g⁻¹ based on activated carbon material at 55 ℃. Cycling data and XPS results demonstrate that Pyr-based ionic liquid with longer alkyl chain is more effective for enhancing the cycling stability of EDLC by suppressing the reductive decomposition of pyrrolidinium cations during cycling at high temperatures.

• E2M - 전기 전자와 첨단 소재
• /
• 제10권8호
• /
• pp.763-769
• /
• 1997

In this study we have synthesized Zno:Eu phosphors under various sintering atmospheres and temperatures. The analysis of X-ray diffractometer measurement indicates that for Zno:EuCl$_3$ phosphors sintered in air and vacuum 뗘 exists in the host lattice as Eu$_2$O$_3$and EuOCl respectively. From the photoluminescence for the phosphors sintered in vacuum Eu removes the broad-band emission of the ZnO host consequently isolating the red emission due to Eu$^{3+}$ ion and improves the color purity of red emission. The photoluminescence excitation and time resolving spectrum measurements suggest that energy-transfer process occurres from the self-activated defect center in ZnO host the Eu$^{3+}$ ion which exist in the host lattice in the form of EuOCl.

• 한국인쇄학회지
• /
• 제19권2호
• /
• pp.49-57
• /
• 2001

This thesis attempts to study ink transition for on the polycarbonate multicalculator plate for automobile. For this study, the change of weight by screen printed ink transition on polycarbonate material by ink viscosity(be diluted ; 0%, 5%, 10%, 20%) was observed. The weight by screen printed ink is depended on amount of added solvent. We have studied change of the weight by the transition of the ink that was screen-printed on polycarbonate which is to be printed according to the viscosity of the ink (diluent: undiluted solution 5%, 10%, 15%, 20%). This shows that ink transition become activated since the amount of ink(or/and the viscosity of ink) is increased.

• 한국분말재료학회지
• /
• 제11권5호
• /
• pp.369-375
• /
• 2004

A new concept of tungsten heavy alloy composite was suggested and manufactured in this study for the kinetic energy penetrator. The composite heavy alloy was composed of two parts, the center was molybdenum added heavy alloy compositions which were designed to promote the self-sharpening effect and outside was conventional heavy alloy in order to sustain the severe stress condition in the muzzle during the firing. The center part showed an intergranular and brittle mode at tungsten/tungsten interfaces by which self-sharpening effect could be activated. On the other hand, that of outside showed conventional ductile fracture mode under high strain rate condition. From the sub-scale penetration test, the depth of penetration in heavy alloy composites showed greater values than those of conventional tungsten heavy alloys. It is suggested that the heavy alloy composite could be considered as one of the future penetrator materials.

• 전기화학회지
• /
• 제5권4호
• /
• pp.192-196
• /
• 2002

Ionic liquids based on l-ethyl-3-methylimidazolium cation $(EMI^+)$ and inorganic or organic anions containing fluorine atoms were applied to electrolyte materials for double-layer capacitors. The double-layer capacitors composed of a pair of activated carbon electrodes and an ionic liquid selected from $EMIBF_4,\; EMINbF_6,\;EMITaF_6,\;EMICF_3SO_3,\;EMI(CF_3SO_2)_2N,\;and\;EMI(C_2F_5SO_2)_2N$ showed inferior low-temperature characteristics to those of a conventional nonaqueous electrolyte based on propylene carbonate (PC) solvent. On the other hand, the capacitor using $EMIF{\cdot}2.3HF$ showed excellent low-temperature characteristics due to its high conductivity at low temperatures, however, it had a lower working voltage $(\~2V)$ than the conventional nonaqueous counterpart $(\~3V)$.

• E2M - 전기 전자와 첨단 소재
• /
• 제9권10호
• /
• pp.1001-1007
• /
• 1996

The conduction mechanisms of the off-current in low temperature (.leq. >$600^{\circ}C$) processed polycrystalline silicon thin film transistors (LTP poly-Si TFT'S) have been systematically studied. Especially, the temperature and bias dependence of the off-current between hydrogenated and nonhydrogenated poly-Si TFT's were investigated and compared. The off-current of nonhydrogenated poly-Si TF's is because of a resistive current at low gate and drain voltage, thermally activated current at high gate and low drain voltage, and Poole-Frenkel emission current in the depletion region near the drain at high gate and drain voltage. After hydrogenation it has shown that the off -current mechanism is caused mainly by thermal activation and that the field-induced current component is suppressed.

• E2M - 전기 전자와 첨단 소재
• /
• 제4권4호
• /
• pp.338-343
• /
• 1991

활성화된 반응성 증발법을 이용하여 비저항 .rho.=1*$10^{-3}$.OMEGA..cm, 이동도 .mu.=4*$10^{3}$$cm^{2}$/V.sec이고 두께가 약 400.angs.인 In$_{2}$O$_{3}$ 박막을 실온에서 유리기판에 생성시켰다. 광투과율은 파장 400-800nm범위에서 80% 이상으로 나타났고 구조는 무정형인 것으로 나타났다. 낮은 저항의 In$_{2}$O$_{3}$ 박막은 Ar과 $O_{2}$의 압력을 적적히 조절함으로서 얻을 수 있을 것으로 분석되었고 약 350.deg.C의 온도로 30분간 열처리로서 정형화할 수 있는 것으로 판단되었다. 또한 증발율, 이동도 및 저항과 캐리어 농도와의 상관관계도 고찰하여 보았다.

• 대한임상독성학회지
• /
• 제3권2호
• /
• pp.114-118
• /
• 2005

Ingestion of plant material rarely manifest in clinical intoxication. This is due to the relatively low toxicity of most plants in Korea. But, veratrum is an important plant on account of its highly toxic alkaloids. Five cases of Veratrum grandiflonum mass poisoning are described. Clinical symptoms occurred quickly, within 30 min. Vomiting, a fall in blood pressure and bradycardia was observed. Treatments in the emergency department included gastric lavage, activated charcoal, and administration of atropine and dopamine for bradycardia and hypotension. Although one of them experienced profound hypotension, bradycardia and mental change, the outcomes were favorable in all cases, producing a complete cure without any sequellae at discharge.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2004년도 추계학술대회
• /
• pp.272-273
• /
• 2004

Filter media are one of themost important choices when bilfiltration is applied. Filter media provide adsorbing microbes with available sites for residence and the residential cells grow to degrade or decompose target waste gases. Up to date, filter media were only qualitatively analyzed. As a quantitative approach to filter material for biofiltration, a simple model based on reaction kinetics and mass action law (Ottengraf's Model in 1983) was presented. Cork, zeolite, and granulated activated carbon were tested in terms of effective surface area, cell covered fraction of adsorbing sites, surface roughness, and pore size distribution. The cell covered fraction, surface roughness and hydrophilicity was found to be closely related to the efficiency of gas degradation in biofiltration. The cork was the best candidate for cell residence and growth in this work.