• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1504-1510
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• 2016

The aim of this study is to improve properties both glass transition temperature($T_g$) and coefficient of thermal expansion(CTE) using epoxy/micro-nano alumina composites with adding glycerol diglycidyl ether (GDE:1,2,3,5g). This paper deals with the effects of GDE addition for epoxy/micro alumina contents (40, 50, 60wt%)+surface modified nano alumina(1_phr) composites. 20 kinds specimen were prepared with containing micro, nano alumina and GDE as a micro composites(10, 20, 30, 40, 50, 60, 70wt%) or a nano/micro alumina composites(1phr/40, 50, 60wt%). Average particle size of nano and micro alumina used were 30nm and $1{\sim}2{\mu}m$, respectively. The micro alumina used were alpha phase with Heterogeneous and nano alumina were gamma phase particles of spherical shape. The glass transition temperature and coefficients of thermal expansion was evaluated by DSC and TMA. The glass transition temperature decreased and coefficients of thermal expansion become smaller with filled contents of epoxy/micro alumina composites. On the other hand, $T_g$ and CTE as GDE addition variation(1,2,3,5g) of epoxy/micro-nano alumina composites decreased and increased respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.556-559
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• 2006

벌크형태의 태양전지 기판을 대체할 목적으로 연성기판을 적응한 태양전지 개발이 활발하게 진행되고 있으며, 주재료는 플라스틱 기판, 금속기판 등이 있다 그러나 기존의 연성기판인 플라스틱의 경우 열과, 내구성, 화학약품에 약하다는 단점이 있으며, 금속기판은 높은 생산원가, 박막화의 어려움 등의 문제를 안고 있다 이러한 문제를 극복하기 위해 전주성형법으로 제조된 철-니켈계 연성기판을 개발하였다. 이 연성기판의 경우 고온의 공정조건에서도 열팽창율이 플라스틱 기판보다 낮으며, 기존의 금속기판 보다 저렴한 생산단가로 쉽게 극박화 할 수 있다는 것이다. 전주성형법을 적용하여 40Ni, 45Ni, 52Ni 연성기관을 제조하였으며, TMA 장비를 사용하여 각 연성기판의 열팽창 계수를 측정한 결과 6.36, 6.78, $10.93{\mu}m/m^{\circ}C$로 기존의 연성기판인 플라스틱, 금속에 비해 낮은 열팽창 계수를 가짐으로서 고온 공정 중에 안정성 요구를 충분히 충족시킬 수 있다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.689-689
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• 2013

Atomic layer deposition (ALD)에 의한 알루미늄 산화 막(Al2O3)은 고효율 결정질 실리콘 태양전지를 위한 우수한 표면 패시베이션 특성을 제공한다. 알루미늄 산화막는 고정적인 음전하를 가지고 있기 때문에 p-형 실리콘 태양 전지 후면은 전계에 의한 우수한 패시베이션 효과를 형성한다. 그러나, ALD 방식으로 증착된 알루미늄 산화막은 매우 긴 공정 시간을 필요로 하기 때문에 기존의 실리콘 태양 전지 공정에 적용하기가 어렵다. 본 논문에서는 알루미늄 산화막 형성에서 공정 시간을 줄이기 위해 Plasma assisted atomic layer deposition (PA-ALD) 방식을 적용했다. PA-ALD 기술은 trimethylaluminum (TMA)과 O2를 사용하여 기판 표면에 알루미늄 산화막을 증착하는 것으로 ALD 방식과 유사하지만, O2 플라즈마를 사용함으로써 증착 속도를 향상시킬 수 있다. 이는 좋은 패시베이션 특성을 가지는 알루미늄 산화막을 실리콘 태양전지양산 공정에 적용할 수 있는 가능성을 제시한다. PA-ALD 방식에 의한 알루미늄 산화막의 패시베이션 특성을 최적화하기 위해서 증착 후 열처리 조건에 대한 연구도 수행하였다. 막증착률이 1.1${\AA}$/cycle인 Al2O3층의 두께 변화에 따른 특성을 최적화하기 위해 공정 온도를 $250^{\circ}C$ 고정하고, 열처리 온도와 시간을 가변하였으며 유효 반송자수명을 측정하여 알루미늄 산화막의 패시베이션 특성을 확인했다.

• Journal of Magnetics
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• v.1 no.2
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• pp.75-81
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• 1996

Study on the HDDr Characteristics of Nd16Fe76-xB8Zrx (x=0-2.0) Alloys and the Magnetic Properties of the HDDR Materials Nd16Fe76-xB8Zrx (where x=0-2.0) have been studied to see the effect of Zr addition on HDDR characteristics. A particular emphasis was place upon the anisotropy of the HDDR material. Anisotropy of the HDDR powder material has been evaluated by comparing the remanence values of the aligned sample measured along the aligning direction and the direction perpendicular to it. The HDDR characteristics of the alloys were investigated by means of DAT and TPA. Magnetic chracterisation of the HDDR processed materials was performed using a VSM and a TMA. The magnetic domain structure of the HDDR materials was examined by means of polarised microscope using a solid HDDR processed material. It has veen found that small addition (0.1 at %) of Zr to Nd-Fe-B-type alloy retards thedisproportionatio kinetics of the hydrogenated material. Desorption characteristic of the disproportionated materials has been found not to be affected significantly by the Zr addition. The Zr addition has been found to facilitate size of the powder. As the particle size decreases, the intrinsic coercivity decreases radically, and this is explained in terms of structural damage and/or oxidation caused during mechanical milling. It has also been found that the degree of alignment representing the anisotropic character of the HDDR powder is enhanced with decreasing particle size. Alloys with compositions based on

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.95-101
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• 1995

Crystallizable glasses with precipitation of celsian, anorthite, wollastonite and gahnite were prepared for the purpose of insulating dielectric layers in devices such as integrated circuit substrates. The starting glasses were prepared by melting the batches for 1 hour at 1450.deg. C and then Quenching to a distilled water. And crystallization behavior of these glasses were studied by DTA, TMA, XRD analysis and by the measurement of dielectric properties. The overall composition of the glass-ceramic consists in weight percent of 30-35% A1$_{2}$O$_{3}$, 13-26% BaO, 5-21% CaO, 10-24% ZnO, 4.5-9.0% TiO$_{2}$ and 4-8% B$_{2}$O$_{3}$. As a result, in barium-rich glasses only celsian phase was developed in the range of 850-900.deg. C. Also, the thermal expansion coefficient, dielectric constant and quality factor of these glass-ceramics were 68*10$^{-7}$ /.deg. C, about 9 and more than 1000, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.242-242
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• 2010

산화 알루미늄($Al_2O_3$) 박막을 p-type Czochralski(CZ) Si 위에 Remote Plasma Atomic Layer Deposition(RPALD)을 이용하여 저온 공정으로 증착하였다. Photolithography 공정으로 grid 패턴을 형성한 후 열 증착기로 알루미늄을 증착하여 MIS-IL (Metal-Insulator-Semiconductor Inversion Layer) solar cell을 제작하였다. 반응소스로는 Trimethylaluminum (TMA)과 $O_2$를 이용하였다. $Al_2O_3$ 박막의 전기적 특성 평가를 위해 MIS capacitor를 제작하여 Capacitance-voltage (C-V), Current-voltage (I-V), Interface state density ($D_{it}$)를 평가하였으며 Solar simulator를 이용하여 MIS-IL Solar cell의 Efficiency을 측정하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.13-14
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• 2008

$Al_2O_3$ thin films were deposited on GaN (0001) by remote plasma atomic layer deposition (RPALD) technique using trimethylaluminum (TMA) precursor and oxygen radicals in the temperature range of 25 ~ $500^{\circ}C$. Growth rate per cycle was varied with substrate temperature from 1.8 $\breve{A}$/ cycle at $25^{\circ}C$ to 0.8 $\breve{A}$/cycle at $500^{\circ}C$. The chemical structure of the $Al_2O_3$ thin films was studied using X-ray photo electron spectroscopy (XPS). Excellent electrical properties of $Al_2O_3$/GaN MIS capacitor were grown at $300^{\circ}C$ process temperature.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.104-107
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• 2004

In this work, the blend of diglycidylether of bisphenol A (DGEBA) and modified polyurethane (PU) was prepared and characterized in the cure behaviors and mechanical interfacial properties. The N-benzylpyrazinium hexafluoroantimonate was used as a cationic initiator for cure, and the content of PU was varied within 0-20 phr. The cure behaviors and mechanical interfacial properties were studied by DSC, near­IR, and the critical stress intensity actor $(K_{IC})$ measurements. Also thermal stabilities were carried out by TMA and TGA analyses. As a result, the cure activation energy $(E_a)$ and the conversion $(\alpha)$ were slightly increased with increasing the PU content, and a maximum value was found at 10 phr PU. The mechanical interfacial properties measured from $K_{IC}$ showed a similar behaviors with the results of conversion. These results were probably due to the increase of the hydrogen bonding between the hydroxyl groups of DGEBA and isocyanate groups in PU.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.169-176
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• 1988

In order to obtain the objective indices which can assess the quality and the shelf-life of dried squid, nonenzymatic browning, carbonyl value, trimethyl amine (TMA) and trimethyl amine oxide (TMAO) decrease and panel test were determined in dried squid at various water activity levels. When the data of nonenzymatic browning fit a zero order equation, $r^2$ value were more than 0.92 except aw 0.52 for 0.8241. Through variance analysis for the data of browning extent and TMAO decrease, the confidence limits of regression equation were $99\%$ and their limit values of shelf-life were shown 0.45390 O. D./g. solid and 190.322 g/g respectively. In case of TMAO, $r^2$ value was calculated more than 0.95. Linear regression equation for the correlation between browning data and average panel score was Y=0.6138-0.053X and its $r^2$ value was 0.9285. Also in TMAO decrease, the equation was InY=2.0314+0.08269x and $r^2$ value was 0.7854. The shelf-life, evaluated by nonenzymatic browning, TMAO decrease and panel test, was 110-170 days at aw 0.45-0.76 except aw 0.15.

• Korean journal of food and cookery science
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• v.6 no.2
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• pp.97-104
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• 1990

건조 수산가공품 및 혼합조미료 각 5종의 위생적 살균 및 저장방법의 개발을 목적으로 현행살균 방법으로 살균효과의 불충분, 제품의 품질저하, 약제성분의 잔유 등 많은 문제점을 내포한 ethylene oxide에 의한훈증처리와 방사선 조사와의 미생물 살균효과, 이화학적 특성 및 관능적 품질에 미치는 영향을 검토한 결과는 다음과 같다. 시료의 미생물 오염은 전 세균이 $10^3~10^7$ CFU/g으로 그중 90%이상이 내열성 세균이었으며, 곰팡이류는 $10^2~10^3$ CFU/g, 대장균도 시료 5종에서 $10^2~10^6$ CFU/g이나 오염되었다. 살균효과 실험에서 대장균군, 곰팡이류는 5~10 kGy 방사선 조사로서 완전 사멸되었으며, 전세균도 오염도가 매우 높았던 혼합조미료 몇종을 제외하고는 제거되었다. 반면, ethylene oxide훈증처리는 전 미생물의 살균이 불충분하였다. 이 화학적 특성 즉, TBA가 TMA-N 함량, 아미노산, 무기질, 색도 등은 적정 선량의 방사선 조사로서는 무처리구 시료와 거의 차이가 없었으나, ethylene oxide 훈증처리구는 심한 품질의 변화를 나타내었다. 또한 관능검사에 의한 전반적 기호성에 있어서도 방사선조사구가 무처리구 및 ethylene oxide 처리구보다 유의적으로 우수함을 나타냈다.