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Metal Organic Chemical Vapor Deposition법을 이용한 Germanium 전구체의 증착 특성 연구
김선희,김봉준,김도형,이준기,Kim, Sun-Hee,Kim, Bong-June,Kim, Do-Heyoung,Lee, June-Key 한국재료학회 2008 한국재료학회지 Vol.18 No.6
Polycrystalline germanium (Ge) thin films were grown by metal organic chemical vapor deposition (MOCVD) using tetra-allyl germanium [$Ge(allyl)_4$], and germane ($GeH_4$) as precursors. Ge thin films were grown on a $TiN(50nm)/SiO_2/Si$ substrate by varying the growth conditions of the reactive gas ($H_2$), temperature ($300-700^{\circ}C$) and pressure (1-760Torr). $H_2$ gas helps to remove carbon from Ge film for a $Ge(allyl)_4$ precursor but not for a $GeH_4$ precursor. $Ge(allyl)_4$ exhibits island growth (VW mode) characteristics under conditions of 760Torr at $400-700^{\circ}C$, whereas $GeH_4$ shows a layer growth pattern (FM mode) under conditions of 5Torr at $400-700^{\circ}C$. The activation energies of the two precursors under optimized deposition conditions were 13.4 KJ/mol and 31.0 KJ/mol, respectively.
테르펜 개질 페놀 수지 구조에 따른 배합고무 물성 변화
김건옥 ( Kun Ok Kim ),김도형 ( Do-heyoung Kim ),송요순 ( Yo Soon Song ) 한국공업화학회 2020 공업화학 Vol.31 No.3
테르펜 개질 페놀 수지는 타이어의 주행 안전성과 관련 있는 웨트 트랙션과 연비와 관련된 구름저항을 개선하기 위해 사용한다. 이 시험은 테르펜 개질 페놀 수지의 기본 구조가 각각 알파 피넨, 베타 피넨, 델타 리모넨으로 달리한 수지를 타이어 트레드 배합물에 첨가하여 알킬 페놀 수지의 배합물과 물성 차이를 비교하였다. 알킬 페놀 수지는 웨트 트랙션과 관련 있는 0 ℃에서 탄젠트 델타가 테르펜 개질 페놀 수지와 큰 차이가 없지만 구름저항과 관련 있는 80 ℃에서 탄젠트 델타가 높게 나타나 연비 개선 효과가 적었다. 테르펜 개질 페놀 수지 중 베타 피넨은 웨트 트랙션과 연비 개선 효과가 다른 수지에 비해 고르게 나타났으며, 델타 리모넨 수지는 웨트 트랙션 개선효과가 가장 좋았고, 인장강도 및 마모 성능은 알킬 페놀 수지가 비교적 높게 나왔다. 모든 테르펜 개질 수지는 구름저항에서 알킬 페놀 수지보다 우수하여 연비 개선효과 좋다고 할 수 있으며, 블랭크에 비해 다른 특성도 나아지는 효과를 보였다. 이 시험에서 사용된 페놀 수지의 특성을 참고하여 타이어 컴파운드를 배합할 때 개질된 테르펜 페놀 수지를 선택하면 웨트 트랙션, 구름저항 등의 특성을 효과적으로 개선한 컴파운드를 만들 수 있다. Terpene-modified phenolic resins were used to improve the tires wet traction related to the driving safety and also rolling resistance related to fuel efficiency. In this work, alpha-pinene, beta pinene, and delta limonene resins, which constitute different basic structures of terpene-modified phenolic resins, were individually added to the tread compounds of tires and their physical properties were compared with those of the alkyl phenol resin compounds. Alkyl phenolic resins showed no significant difference in tangent delta from terpene-modified phenolic resins at 0 ℃, which is related to wet traction, but showed higher tangent delta at 80 ℃, which is related to rolling resistance, indicating smaller fuel efficiency improvement effects. Among the terpene-modified phenolic resins, beta pinene one showed improved wet traction and fuel efficiency compared to those of other resins. Delta limonene resin showed the best wet traction improvement effect, and alkyl phenolic resins showed relatively high tensile strength and abrasion property. All terpene-modified resins exhibited better rolling resistance than those of alkyl phenolic ones so that they can be said to have better fuel efficiency improvement effects and also to improve other properties compared to those of blanks. Terpene-modified phenolic resins could be used when mixing tire compounds referring to the properties of the phenolic resins revealed in this work, which could result in preparing compounds with improved wet traction and rolling resistance.
화학기상 증착법을 이용하여 제조된 텅스텐 산화막의 전기변색 소자 응용 연구
정훈 ( Hun Jung ),선우창신 ( Chang Shin Sunwoo ),김도형 ( Do Heyoung Kim ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.4
A study on chemical vapor deposition(CVD) of WO3 and the electrochromic properties of the CVD WO3 films have been carried out. The crystalinity, purity, and growth rate of the films depending on substrate temperatures are investigated. The highest growth rate is 8μm/min at the substrate temperatures above 300℃ and the estimated activation energy for overall film growth is about 45.9 kJ/mol at the temperatures of 225~275℃, where the CVD process is controlled by a surface reaction kinetics. The films grown below 275℃ are amorphous, while those deposited above 300℃ are crystalline. The effects of thickness and deposition temperature of the WO3 films on electrochromic activity are also investigated. The coloration efficiency of the films increases with increase in film thickness and decrease in deposition temperature.
Compositional Quenching 으로 제조한 PP / PU 블렌드의 모플로지 및 물성
임경택(Gyeong Taek Lim),주민혁(Min Hyuk Ju),김도형(Do Heyoung Kim),송기찬(Ki Chan Song),김수경(Su Kyung Kim) 한국고무학회 2001 엘라스토머 및 콤포지트 Vol.36 No.3
N/A Polypropylene(PP)/Polyurethane(PU) blends with reactive compatibilizers were prepared by the compositional quenching process. Malefic anhydride grafted PP(MPP) and hydroxyethyl maleimide grafted PP(HPP) were introduced as reactive compatibilizers. The formation of HPP and the reactions of compatibilizers with the PU components were confirmed by FT-IR spectroscopy. The morphology, tensile properties, thermal stability, and surface property were studied. The blends prepared by the compositional quenching showed better dispersed domain morphology than the melt blends. The PU domain size became more uniform and reduced in size with increasing the amount of compatibilizers. The blends with HPP showed slightly smaller domain size than the blends with MPP. The blends with compatibilizers all showed improved tensile properties, surface property, and thermal stability due to the interfacial adhesion effect. The blends with MPP showed higher surface energy than the blends with HPP, but the latter showed better thermal stability compared to the former.
송요순,김도형 전남대학교 촉매연구소 2001 觸媒硏究 論文集 Vol.22 No.-
Heterogeneous nucleation rate of water vapor on smooth surfaces, e. g. an immiscible liquid surface was investigated. The nucleation and growth of condensate nuclei could occur both by the direct addition of molecules from the vapor and from those adsorbed on the substrate. The vapor-condensate-substrate interfacial force, the critical supersaturation, number of adsorbed molecules were different ways of expressing the affinity between vapor molecules and substrate surface. We found that adsorbed molecules were usually far more important to the nucleation process than those in the vapor phase. The heterogeneous nucleation rate of water vapor on some liquid surfaces was studied also. The critical supersaturation was measured differently with interfacial tension. There were a little bit differences between Volmer theory and experimental values.