• 한국안광학회지
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• 제8권2호
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• pp.111-117
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• 2003

국내외 썬글라스 반미러 코팅렌즈의 광학적 특성을 파악하기 위해, 분광광도계를 이용하여 반미러 코팅렌즈의 반사율을 측정하였으며, Macleod 프로그램을 이용해 계산한 결과와 비교 분석하였다. 또한 황금 색깔이 나는 TiN을 이용한 반미러 코팅렌즈를 설계하였고, 광학특성을 조사하였다. 반미러 코팅렌즈의 분석결과, 은색 투톤(two tone) 반미러 코팅은 금속 크롬(Cr)을 사용하였으며 경도를 증가시키기 위하여 크롬위에 $SiO_2$(또는 $Al_2O_3$)를 증착하여 사용하였다. 크롬 위에 증착되는 $SiO_2$의 두께는 10nm 정도가 적정한 것으로 판단된다. 칼라 반미러 코팅의 경우 디자인 결과는 각각 다음과 같다 ; blue 계열은 [air|$SiO_2$(66.3)|$TiO_2$(129.0)|$SiO_2$(62.9)|$SiO_2$(26.0)|$TiO_2$(120.3)|$SiO_2$(9.1)|glass]이며, gold 계열은 [air|$SiO_2$(60.6)|$TiO_2$(86.2)|$SiO_2$(13.5)|$TiO_2$(86.8)|$SiO_2$(214.38)|glass]이며, green 계열은 [air|$SiO_2$(74.3)|$TiO_2$(75.8)|$SiO_2$(44.3)|$TiO_2$(11.6)|$SiO_2$(160.8)|$TiO_2$(12.9)|$SiO_2$(183.3)|$TiO_2$(143.8)|glass]이며, silver 계열은 [air|$SiO_2$(21.2)|$TiO_2$(49.7)|$SiO_2$(149.3)|glass]이다. white 반미러 코팅인 경우는 [air|$SiO_2$(17nm)|$TiO_2$(43nm)(또는 $ZrO_2$)|$SiO_2$(87nm) polysiloxane($4.46{\mu}m$)|glass or CR-39]이며, 가시광선 영역(400~700 nm)에서 평균 19%의 반사율을 가지며 흡수가 적기 때문에 약 80%의 투과율을 보이는 white 타입의 반미러가 되게 된다. 황금빛 색깔을 띠는 반미러 코팅렌즈의 설계에 있어서 [air|$SiO_2$(170nm)|TiN(15nm)|glass]가 되면 CIE 좌표값은 거의 [air|Au(150nm)|glass]의 좌표값과 유사해지는 것을 볼 수 있었다.

• 한국세라믹학회지
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• 제38권2호
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• pp.179-182
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• 2001

Al$_2$O$_3$-5 vol% SiC 나노복합재료의 sinter plus HIP에 의한 치밀화시 일어나는 기공의 변화에 초점을 두어 치밀화 거동을 관찰하였다. $Al_2$O$_3$-SiC 시편은 질소분위기 중의 상압소결과 이후의 열간정수압소결(HIP)에 의해 완전치밀화가 이루어졌다. 155$0^{\circ}C$의 상압소결에 의해서는 90%의 비교적 낮은 상대밀도가 얻어졌으나, 기공의 폐기공화로 이후의 열간정수압소결(HIP)에 의해 99.6%의 완전치밀화가 가능하였다. 상압소결한 시편을 X-선 회절기와 주사전자현미경(SEM)으로 관찰한 결과, 선택적으로 시편 표면부에서만 SiAl$_{6}$O$_2$N$_{6}$과 AlN 등으로 이루어진 치밀화된 반응층을 확인할 수 있었으며, 이러한 표면 반응층이 비교적 낮은 상대밀도의 시편내의 모든 기공을 폐기공화하는 효과를 주는 것을 알 수 있었다.

• 한국결정성장학회지
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• 제32권3호
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• pp.103-106
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• 2022

소다석회유리에서 Al₂O₃가 isokom 온도에 미치는 영향을 Lakatos 모델을 이용하여 분석하였다. Na₂O와 CaO의 함량이 같고 SiO₂의 양이 0.5 mol% 감소하고 Al₂O₃ 양이 0.5 mol% 증가했을 때 isokom 온도는 log η = 12.3, 10, 6.6, 1에서 각각 3.1, 3.3, 3.6, 7.2℃ 높아졌다. 한편, SiO₂와 Na₂O의 함양이 같고 CaO가 0.5 mol% 감소하고 Al₂O₃가 0.5 mol% 증가한 경우는 log η = 12.3, 10, 6.6, 1에서 각각 1.6, 2.3, 4.1, 17.7℃ isokom 온도가 높아졌다.

• 한국세라믹학회지
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• 제47권5호
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• pp.467-473
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• 2010

The objective of this study is to prepare lead-free thick film resistor (TFR) paste compatible with AlN substrate for hybrid microelectronics. For this purpose, CaO-ZnO-$B_2O_3-Al_2O_3-SiO_2$ glass system was chosen as a sintering aid of $RuO_2$. The effects of the weight ratio of CaO to ZnO in glass composition, the glass content and the sintering temperature on the electrical properties of TFR were investigated. $RuO_2$ as a conductive and glass powder were dispersed in an organic binder to obtain printable paste and then thick-film was formed by screen printing, followed by sintering at the range between $750^{\circ}C$ and $900^{\circ}C$ for 10 min with a heating rate of $50^{\circ}C$/min in an ambient atmosphere. The addition of ZnO to glass composition and sintering at higher temperature resulted in increasing sheet resistance and decreasing temperature coefficient of resistance. Using $RuO_2$-based resistor paste containing 40 wt%glass of CaO-20.5%ZnO-25%$B_2O_3$-7%$Al_2O_3$-15%$SiO_2$ composition, it is possible to produce thick film resistor on AlN substrate with sheet resistance of $10.6\Omega/\spuare$ and the temperature coefficient of resistance of 702ppm/$^{\circ}C$ after sintering at $850^{\circ}C$.

• 한국세라믹학회지
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• 제35권4호
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• pp.311-318
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• 1998

The reaction bonded alumina ceramics with reinforced particles which have low shrinkage were pro-duced by blending of SiC or TiC or ZrO2 powders to the mixture of Al metal and Al2O3 powder. The powd-ers were attrition milled isostantically pressed and preheated tio 110$0^{\circ}C$ with a heating rate of $1.5^{\circ}C$/min The specimens were then sintered at the temperature range 1500 to 1$600^{\circ}C$ for 5 hours with a heating rate of 5$^{\circ}C$/min. The specimens showed 5-9% weight gain and 2-9% dimensional expansion through the complete oxidation of Al after preheating up to 11--$^{\circ}C$ the overall dimensional change of the specimens after the reaction sintering at 1500-1$600^{\circ}C$ was 6-12% The maximum densities were 92% theoretical. The fine grain-ed(average grain size :0.4 ${\mu}{\textrm}{m}$) microstructure were observed in the specimen with ZrO2 and SiC. But the microstructure of specimen with TiC was relatively coarse.(average grain size : 2.1 ${\mu}{\textrm}{m}$) The mullite phase was formed by the reaction of Al2O3 and SiO2 in a specimen with SiC. In the TiC contained specimen TiC was oxidized into TiO2 and finally reacted with Al2O3 to form Al2TiO5 during sintering.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.163-166
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• 2003

The electrothermal simulation of high voltage LIGBT(Lateral Insulated Gate Bipolar Transistor) in thin Silicon on insulator (SOI) and Silicon on sapphire (SOS) for thermal conductivity and sink is performed by means of MEDICI. The finite element simulations demonstrate that the thermal conductivity of the buried oxide is an important parameter for the modeling of the thermal behavior of silicon-on-insulator (SOI) devices. In this paper, using for SOI LIGBT, we simulated electrothermal for device that insulator layer with $SiO_2\;and\;Al_2O_3$ at before and after latch up to measured the thermal conductivity and temperature distribution of whole device and verified that SOI LIGBT with $Al_2O_3$ insulator had good thermal conductivity and reliability

• 한국주조공학회지
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• 제5권3호
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• pp.19-26
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• 1985

This study has been carried out to examine into wettability of Cu-5%Sn alloy in $Al_2O_3$, MgO, $SiO_2$ and graphite, respectively and investigated into the change in macrostructure of Cu-5%Sn alloy according to kind and mixing rate of mold-coating. The results obtained from the experiment are summerized as follows; 1. Cu Cu-5%Sn alloy, wettabilities of $Al_2O_3$ and MgO were good, on the other hand, wettabilities of $SiO_2$ and graphite were bad. 2. The fine equiaxed zone was created because of the role of $Al_2O_3$ and MgO as preferential nucleation sites. 3. Notwithstanding change of mixing rate of $SiO_2$ in mold coating the equixed zone was not created. 4. The area of equiaxed zone was varied according to mixing rate in the case of using $Al_2O_3$ and MgO in mold-coating.

• 한국세라믹학회지
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• 제37권2호
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• pp.117-121
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• 2000

Er-doped sodiumborosilicate glass films for waveguides amplifier were fabricated by Aerosol Flame Deposition(AFD) method. Al2O3 was added to sodium borosilicate glass films to suppress the formation of crystalline phase and control the refractive index. the formation of crystalline phase was suppressed above Al2O3 of 6 wt%. As the amount of Al2O3 increased from 2 to 12 wt% the refractive index of glass films increased lineary from 1.4595 up to 1.4710. After the core of 77SiO2-15B2O3-8Na2O＋6 wt%Al2O3＋8wt%Er2O3 was coated on the buffer layer of 77SiO2-15B2O3-8Na2O＋6 wt%Al2O3, the core was etched by reactive ion etching. The absorption spectrum of 3 cm waveguide amplifier showed two peaks of 1530 and 1550 nm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.129-130
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• 2009

The P/E characteristics of $HfO_2$ CTF memory capacitor with $SiO_2/HfO_2/Al_2O_3$(OHA) engineered tunnel barrier were investigated. After a growth of thermal oxide with a thickness of 2 nm, 1 nm $HfO_2$ and 3 $Al_2O_3$ layers were deposited by atomic layer deposition (ALD) system. The band offset was calculated by analysis of conduction mechanisms through Fowler-Nordheim (FN) plot and Direct Tunneling (DT) plot. Moreover the PIE characteristics of $HfO_2$ CTF memory capacitor with OHA tunnel barrier was presented.

• 한국재료학회지
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• 제15권10호
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• pp.644-651
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• 2005

The thermal analysis of $Al(OH)_3-SiO_2-AIF_3$ system was done. The thermal behaviors of components and the effect of moisture on the formation of mullite were investigated via TG-DTA and XRD analysis. The mixture of $Al(OH)_3,\;SiO_2,\;AIF_3$showed two endothermic peaks with drastic weight loss and one exothermic peak. Fluorotopaz was formed at $800^{\circ}C$ and turned into mullite completely at $1100^{\circ}C$. But the mixture $Al_2O_3$ of or dehydrated $Al(OH)_3$ and $SiO_2$ could not form mullite even at $1200^{\circ}C$ in which the crystalline phases were $\alpha-Al_2O_3$ ana cristobalite. It was found that the synthesized mullite was aciculate shaped single crystalline whisker.