• 대한기계학회논문집A
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• 제31권4호
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• pp.425-431
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• 2007

[ $Al_2O_3/SiC$ ]composite ceramics were sintered to evaluate the bending strength and elastic wave characteristics. The three-point bending test was carried out under room temperature. The elastic wave was detected by fracture wave detector. The crack healing behavior was investigated from 1373 K to 1723 K. The bending strength of $Al_2O_3/SiC$ composite by nanocomposite is higher than that of $Al_2O_3$ monolithic. Crack-healing behavior depended on an amount of additive powder $Y_2O_3$. In $Al_2O_3/SiC$ composite ceramics with 3 wt. % $Y_2O_3$ for additive powder, the bending strength at 1573 K is about 100% increase than that of the smooth specimens. From the result of wavelet analysis of elastic wave signal, the smooth specimen and heat treated specimen of $Al_2O_3$ monolithic and $Al_2O_3/SiC$ composite ceramics showed characteristics of frequency about 58 kHz. The strength of $Al_2O_3/SiC$ composite ceramics was a little higher than those of $Al_2O_3$ monolithic. The dominant frequencies were high with increasing of $Y_2O_3$ for additive powder. The dominant frequencies had direct connection with the bending strength.

• 한국세라믹학회지
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• 제32권10호
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• pp.1212-1218
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• 1995

Al2O3-coated SiC composite powder and mechanically mixed Al2O3-SiC composite powder were synthesized using Al-isopropoxide and commercial SiC as the starting materials. Experiment results showed that the sinterability of Al2O3-coated SiC composite powder was more improved than the mechanically mixed Al2O3-SiC composite powder by the effect of homogeneous coating of alumina around SiC particles. Hence, the mechanical properties of the former was also much more improved than the latter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.507-510
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• 2000

The purpose of this study is to research and developV$_2$O$_{5}$-SP270 composite electrode for supercapacitor. Property of an electrical double layer capacitor depend both on the technique used to prepare the electrode and on the current collector structure. The study is to research that V$_2$O$_{5}$-carbon composite electrode for supercapacitor with different voltage range. Suprcapacitor cell of V$_2$O$_{5}$-SP270 composite electrode with 25PVDFLiC1O$_4$PC$_{10}$ polymer electrolyte bring out good capacitor performance below 3V. The discharge capacitance of SP270 in 1st cycles was 13F/g at 0.1mA/cm$^2$, 3V. We performed cycle voltammogram, charge/discharge property.y.rty.y.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.445-449
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• 2018

Chromium plating is a common surface treatment technique extensively applied in industry due its excellent properties which include substantial hardness, abrasion resistance, corrosion resistance, surface color, and luster. In this study, the effect of $MoS_2$ particles of the composite coating was investigated. To improve the lubrication of mold, $Cr-P-C/MoS_2$ composite plating was studied by varying the $MoS_2$ content. The current efficiency of the composite plating incorporated $MoS_2$ particles was increased at $MoS_2$ contents of 0.5 and 1.0 g/l due to the incorporation of fine particles. On the other hand, when the content of $MoS_2$ is 1.0 g/l or more, the current efficiency is lowered due to an increase in impact on the cathode surface. In order to evaluate the mechanical properties of Scratch test were conducted. Scratch test confirmed the lubricity and abrasion resistance characteristics revealed that the composite plating with added $MoS_2$ had relatively low surface roughness and uniform surface modification to improve its properties.

• 멤브레인
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• 제20권1호
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• pp.21-28
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• 2010

염료감응형 태양전지에 사용되기 위한 유기/무기 복합소재를 합성하였다. 다양한 분자량(600, 1,500, 2,000, 3,400)의 polyethylene glycol 양 끝단을 ethoxysilane기로 치환하여 전구체를 제조하였으며, 전구체간의 졸-겔 반응을 통하여 복합소재를 합성하였다. 전해질막은 유기/무기 복합소재를 KI 및 $I_2$로 도핑하여 제조하였으며, 제조한 전해질의 이온전도도 특성을 측정하였다. 전해질막의 이온전도도는 원료로 사용한 PEG에 크게 영향을 받았으며 가장 높은 이온전도도는 분자량 2,000의 PEG를 사용한 전해질막에서 볼 수 있었다. 복합전해질막은 이온전도도에 있어서 큰 향상을 보였다. PEO 전해질막에 비하여 분자량 2,000의 PEG를 사용하여 제조한 복합전해질막은 월등하게 높은 이온전도도를 보였다.

• 한국화재소방학회논문지
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• 제26권2호
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• pp.105-111
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• 2012

본 연구에서는 건축외장재로 많이 사용되고 있는 알루미늄복합패널의 일반재와 난연재에 대한 화재성능 비교분석에 관해 연구하였다. 실험방법은 중소형 실험장치 중 콘칼로리미터 실험과 SBI(Single Burning Item)을 적용하여 분석하였다. 그 결과 콘칼로리미터 실험에서 최대 열방출률이 일반 알루미늄복합패널은 $1,293kW/m^2$($75kW/m^2$), 난연 알루미늄복합패널은 $70kW/m^2$($75kW/m^2$)가 측정되었다. SBI 실험에서 화재확산지수가 일반 알루미늄복합패널은 약 743W/s이고 난연 알루미늄복합패널은 약 97 W/s의 값이 측정되었다. 이는 일반 알루미늄복합패널의 경우 건축물 내장재의 성능기준에서 난연기준에도 훨씬 못 미치고, 플래쉬 오버(Flash over) 발생 가능성을 나타내었다. 따라서 이러한 알루미늄복합패널의 화재 위험성을 평가하여 외장재로서 사용 시 갖춰야 할 조건에 대한 기준마련이 시급히 요구된다.

• Restorative Dentistry and Endodontics
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• 제25권1호
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• pp.109-115
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• 2000

This study was designed to evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay. For restorative materials, Z100 and Tetric Ceram were used. For dual cured composite cements, Variolink II((VL II) of three consistency (low, high, ultra high) were used. To determine the optimal microhardness of Z100, Tetric Ceram and Variolink II, each material was packed into the 1mm thickness teflon mold without composite overlay and light cured for 60 seconds. Then the microhardnesses of each sample were measured, averaged and regarded as optimal hardness of each material. To evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay, the composites were packed into 1mm thickness teflon mold, coverd with celluloid strip, and then precured composite overlay which was made of Targis(Ivoclar/Vivadent, Liechtenstein) was positioned. 2 types of visible light curing machine, the power density of one of which was 400$mW/cm^2$ and the other was 900$mW/cm^2$, and one type of argon laser were used to cure the restorative composite and dual cured cement. For each group, 10 sample were assigned. The light curing tip was positioned over the composite overlay and light cured for 1min., 2min. or 3min with visible light curing machine or 15sec, 30 sec, 45sec, and 60 sec with argon laser. The Vickers hardnesses of upper and lower surface of Z100, Tetric Ceram, and 3 types of VL II cement were measured. When the 900 $mW/cm^2$ curing light was used, 2min. was needed for optimal curing of Z100 and Tetric Ceram. Variolink II did not be cured optimally even though the curing time was extended to 3min. When 400$mW/cm^2$ curing light was used, 3min. was necessary for Z100, whereas 3min. was not enough for Tetric Ceram. Variolink II was not cured optimally even though the curing time was extended to 3min. When argon laser was used, Z100, Tetric Ceram and Variolink II were not cured optimally in 60 seconds.

• 한국환경과학회지
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• 제21권11호
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• pp.1379-1388
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• 2012

Odor from sewage treatment plants have the potential to cause significant annoyance and to impact the amenity. In this study, odor emission characteristics at unit process of 48 sewage treatment facilities in 39 plants were evaluated using composite odor concentration and hydrogen sulfide ($H_2S$) concentration. The values of composite odor concentration (geometry mean) and $H_2S$ concentration (median) for sludge treatment processes are higher than those for the other treatment processes. The composite odor concentration and $H_2S$ concentration are distributed over a wide area in each process. Composite odor concentration (dilution ratio) was found to have the significant correlation with $H_2S$ concentration (p=0.000<0.05). The $H_2S$ concentration accounted for 67.1% of composite odor concentration.

• 한국광학회지
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• 제9권2호
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• pp.70-75
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• 1998

동시증착법을 이용하여 ZnS와 SiO$_{2}$를 증착시켜 혼합 박막을 제작하고, 제작된 ZnS-SiO$_{2}$ 혼합 박막의 광학적 특성과 결정구조를 분석하였다. 혼합 박막의 Zn:Si의 원소조성비에 따른 광학적 특성은 Drude 모델을 잘 만족함을 알 수 있었다. 이러한 혼합 박막의 굴절률 특성을 이용하여 단층의 무반사코팅을 설계.제작하였다. 한편, 이온 보조 증착하지 않은 혼합 박막은 비정질 구조를 보였으며, 이온 보조 증착한 혼합 박막은 Zn의 함유량이 43.0%, 56.6%일 때 결정질 구조를 보였다.

• 한국세라믹학회지
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• 제27권4호
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• pp.487-494
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• 1990

$Al_2O_3$-20w/o $ZrO_2$ composite powders were prepared by the emulsion-coprecipitation method and the effects of preparative conditions on powder characteristics were investigated. In the preparation of $Al_2O_3$-$ZrO_2$ composite powders, toluene was used instead of kerosene as the oil phase in emulsions. After coprecipitation, the emulsion was easily broken into a single liquid phase by adding methanol, and then precipitates could be effectively collected by filteration. The fact that all $ZrO_2$ phases present at room temperature in composite powders calcined at $1100^{\circ}C$ after washed by methanol had a tetragonal structure confirmed that methanol-washing enhanced the dispersibility of fine $ZrO_2$ particles in $Al_2O_3$ matrix. $Al_2O_3$-$ZrO_2$ composite powders were spherical particles of 0.2${\mu}{\textrm}{m}$ diameter. Pellets sintered at $1650^{\circ}C$ for 2hrs showed the relative theoretical density of 97.3% and the fracture toughness of 5.01MN/$m^{3/2}$.