도로터널 방재팬 운전효율과 자연환기력 관계연구

박홍채(Park, Hong-Chae),조홍률(Cho, Hong-Ryool),이창우(Lee, Chang-Woo) 한국화재소방학회 2007 한국화재소방학회 학술대회 논문집 Vol.2007 No.춘계

지르콘의 탄소열환원에 의한 ZrC / SiC 의 합성

박홍채,이윤복,이철규,오기동 ( Hong Chae Park,Yoon Bok Lee,Cheol Gyu Lee,Ki Dong Oh ) 한국공업화학회 1994 공업화학 Vol.5 No.6

Ar 또는 Ar/H₂, 가스유통(100∼500㎖/min)하에서 ZrSiO₄/C계 및 ZrSiO₄/Al/C계로부터 ZrC/SiC 복합분체의 합성을 1600℃ 온도범위 내에서 시도하고, 이의 생성기구, 생성속도 및 분체특성을 검토하였다. ZrSiO₄/C계에서는 1400℃ 이상에서 ZrO₂(s)와 SiO(g)가 각각 탄소와 경쟁반응하여 ZrC 및 SiC를 생성하였다. ZrC생성을 위한 겉보기활성화에너지는 약 18.5㎉/㏖(1400-1600℃)이었다. 한편 ZrSiO₄/Al/C계에서는 1200℃ 이상에서 ZrO(g)가 Al(l, g) 및 탄소와 반응하여 ZrC를 생성하였으며, 1300℃ 이상에서는 SiO(g)가 Al(l,g) 및 탄소와 환원-탄화반응하여 SiC를 생성하였다. 1600℃, 5시간 반응으로 얻은 생성물은 평균입경 21.8㎛을 갖는 분말로서 ZrC의 격자정수는 4.679Å, 결정자크기는 640Å이었으며 SiC의 격자정수는 4.135Å, 결정자크기는 540Å 정도이었다. The preparation of ZrC/SiC mixed powders from ZrSiO₄/C and ZrSiO₄/Al/C systems was attempted in the temperature range below 1600℃ under Ar or Ar/H₂ gas flow(100-500㎖/min). The formation mechanism and kinetics of ZrC/SiC were suggested and the resultant powders were characterized. In ZrSiO₄/C system, ZrC and SiC were formed by competitive reaction of ZrO₂(s) and SiO(g) with carbon at temperature higher than 1400℃. The apparent activation energy for the formation of ZrC was approximately 18.5㎉/㏖(1400-1600℃). In ZrSiO₄/Al/C system, ZrC was formed by reaction of ZrO(g) with Al(l, g) and carbon at temperature higher than 1200℃, and SiC was formed by reduction-carbonization of SiO(g) with Al(l, g) and carbon at temperature higher than 1300℃. The products obtained at 1600℃ for 5h consisted of ZrC with lattice constant of 4.679Å and crystallite size of 640Å, and SiC with lattice constant of 4.135Å and crystallite size of 500Å. And also, the mean particle size was about 21.8㎛.

굴패각으로부터 제조된 $\textrm{Al}_2\textrm{O}_3$-CaO내화물의 특성

류수착,박홍채,Ryu, Su-Chak,Park, Hong-Chae 한국재료학회 1998 한국재료학회지 Vol.8 No.1

알루미나와 하소된 귤껍질의 소결반응에 의해 A $I_{2}$ $O_{3}$-CaO내화물이 제조되었다. 치밀화과정에서의 CaO의 영향과 A $I_{2}$ $O_{3}$-CaO 소결체의 특성을 고찰하였다. 소결체의 미세구조와 EDS 결과로 A $I_{2}$ $O_{3}$-CaO화합물을 확인하였다. 145$0^{\circ}C$에서 열처리한 소결체는 2.87/㎤의 부피비중과 12.03%의 겉보기 기공율을 가지며 압축강도는 312kg/$\textrm{cm}^2$이였다. 140$0^{\circ}C$에서 서결체의 열팽창 계수는 6.55Kx10$_{-6}$ $K_{-1}$이였다.

카올린으로부터 알루미나 졸의 형성에 미치는 반응인자의 영향

강효경,박홍채,박희찬 ( Hyo Kyoung Kang,Hong Chae Park,Hee Chan Park ) 한국공업화학회 1997 공업화학 Vol.8 No.4

카올린에서 추출된 황산알루미늄 용액을 이용하여 정밀화학 분야에서 많은 이용이 기대되고있는 알루미나 졸의 제조에 대하여 연구하였다. 교반을 하면서 황산알루미늄용액에 암모니아수를 첨가하여 비정질의 일수산화알루미늄(AlO(OH))를 제조하고, 제조된 입자의 표면에 전기이중층을 형성하기 위해서 초산(CH₃COOH)을 투입하여 안정한 알루미나 졸을 제조하였다. 안정한 알루미나 졸의 제조에 미치는 반응온도, 반응시간, 초산의 농도 등의 영향을 조사하였다. 반응온도 50∼90℃, A/C(건조된 알루미나 량/첨가된 초산의 량) 1.6 (몰비)에서 안정한 졸의 합성이 가능하였으며, 반응시간에는 거의 영향을 받지않았다. 또한, 알루미나의 함량이 1-5vol%까지의 범위에서 안정한 졸이 제조되었고, 이때 졸의 입자크기는 약 5-l0nm 정도이었다. The preparation of alumina sol for fine chemical field from kaolin-derived aluminum sulfate solution is performed. Noncrystalline Al0(OH) was prepared by dropping ammonia water into aluminum sufate solution with stirring. Acetetic acid was added to form the electrical double layers on the particle surface of the slurry, which resulted in a stable sol. The influence of the reaction temperature, reaction time, acetetic acid concentration on the preparation of alumina sol were investigated. Dispersed colloid particles of AlO(OH) were prepared at the reaction temperature of 50-90℃ and 1.6 A / C =1.6 (molar ratio), regardless of the reaction time. Stable alumina sol having a particle size of about 5∼10nm was prepared in the range 1∼5vol% alumina content.

마이크로파에 의한 생분해성 β-TCP/PLGA 복합체의 제조시 β-TCP 첨가량에 따른 영향

진형호,민상호,박홍채,윤석영,Jin, Hyeong-Ho,Min, Sang-Ho,Park, Hong-Chae,Yoon, Seog-Young 한국재료학회 2006 한국재료학회지 Vol.16 No.1

Biodegradable $\beta$-tricalcium phosphate ( $\beta$-TCP)/poly(lactide-co-glycolide) (PLGA) composites were synthesized by in-situ polymerization with microwave energy. The influence of the $\beta$-TCP content in $\beta$-TCP/PLGA composites on the molecular weight, crystallinity, microstructure and mechanical properties was investigated. As the molecular weight of composites decreased, the $\beta$-TCP content increased up to 10 wt.%, while the excess addition of the $\beta$-TCP content above 10 wt.% the molecular weight increased with increasing of the $\beta$-TCP content. This behavior would be due to the superheating effect or nonthermal effect induced by microwave energy. It was found that the bending strength and Young's modulus of the $\beta$-TCP/PLGA composites was proportional to the molecular weight of PLGA. The bending strength of the $\beta$-TCP/PLGA composites ranged from 18 to 38 MPa, while Young's modulus was in the range from 2 to 6 GPa.

$HfO_2$와 $CeO_2$가 첨가된 3Y-TZP 치과용 블록의 제조 및 특성 평가

지상용,지형빈,박홍채,윤석영,Ji, Sang-Yong,Ji, Hyung-Bin,Park, Hong-Chae,Yoon, Seog-Young 한국결정성장학회 2009 韓國結晶成長學會誌 Vol.19 No.6

CAD/CAM 가공이 가능한 치과용 3Y-TZP블록을 제조하였다. 블록 제조를 위하여 3Y-TZP분말에 $HfO_2$와 $CeO_2$ 분말을 첨가하여 $800{\sim}1100^{\circ}C$에서 열처리 한 후 $1450^{\circ}C$에서 소결하였으며, 이때 $HfO_2$와 $CeO_2$ 분말의 첨가량 및 열처리 조건에 따른 블록의 기계적 특성 및 화학적 특성을 조사하였다. EDS mapping 이미지를 통하여 $HfO_2$와 $CeO_2$ 분말이 3Y-TZP에 비교적 분산이 잘되어 있음을 확인하였다. 본 실험에서는 3 wt% $HfO_2$가 첨가된 블록이 가장 높은 굽힘 강도(1 GPa)를 나타내었으며, 3 wt% $CeO_2$가 첨가된 블록은 수열분위기하에서의 $t-ZrO_2$의 안정성을 향상 시키는 것으로 확인되었다. 3Y-TZP block doped with $HfO_2$ and $CeO_2$ for dental ceramic block to the proliferation of CAD/CAM systems was prepared by heating at $800{\sim}1100^{\circ}C$ and then sintering at $1450^{\circ}C$. The influences of heating temperature and addition of $HfO_2$ and $CeO_2$ on the mechanical and chemical properties of 3Y-TZP block were investigated. Using the EDS mapping images, $HfO_2$ and $CeO_2$ was well dispersed in the 3Y-TZP matrix. 3 wt% $HfO_2$ doped block showed the optimum biaxial strength (1 GPa), while 3 wt% $CeO_2$ doped block enhanced the stability of $t-ZrO_2$ under hydrothermal atmosphere.

Synthesis of Aluminum Sulfate from Kaolin and Its Thermal Decomposition

박성수,강효경,박홍채,박희찬,Park, Seong-Su,Gang, Hyo-Gyeong,Park, Hong-Chae,Park, Hui-Chan Materials Research Society of Korea 1998 한국재료학회지 Vol.8 No.2

카올린을 용해시킨 황산용액을 에탄올에 주입함으로써 알루미늄황산염의 침전물, $AI_{2}(SO_{4})_{3}\cdot18H_{2}O$을 제조하고, 그것의 열분해거동을 검토하였다. 합성된 고순도의 침전물은 약 $2\mu\textrm{m}$크기의 판상형태의 입자들로 구성되어져 있었다. 에탄올속으로 카올린을 용해시킨 황산용액의 주입속도를 증가시킴에 따라서 생성된 침전물의 결정사 크기는 감소하였다. 침전물의 탄수 및 탄황산에 대한 겉보기 활성화에너지는 각각 $11.9Kcal mol^{-1}$ 과 $48.2kcal mol^{-1}$ 이었다. Aluminum sulfate, $AI_{2}(SO_4)_3\cdot18H_2O$ was prepared by adding of kaolin-dissolved sulphuric acid into ethanol and its thermal decomposition behavior was discussed. As-synthesized high purity precipitate particles were platelike shapes of $2\mu\textrm{m}$ size. With increasing drop rate of leach liquor into ethanol, the crystallite sizes of the precipitate decreased. The apparent activation energies for dehydration and sulfate decomposition of the precipitate were $11.9Kcal mol^{-1}$ and $48.2kcal mol^{-1}$ respectively.

동결주조 다공질 뮬라이트 세라믹스의 제조와 석탄회의 재활용

김규헌,윤석영,박홍채,Kim, Kyu Heon,Yoon, Seog Young,Park, Hong Chae 한국재료학회 2016 한국재료학회지 Vol.26 No.2

In order to fabricate porous mullite ceramics with controlled pore structure and improved mechanical strength, a freeze casting route has been processed using camphene mixed with tertiary-butyl alcohol (TBA) and coal fly ash/alumina as the solvent and the ceramic material, respectively. After sintering, the solidification characteristics of camphene and TBA solvent were evident in the pore morphology, i.e., dendritic and straight pore channels formed along the solidification directions of camphene and TBA ice, respectively, after sublimation. Also, the presence of microcracks was observed in the bodies sintered at $1500^{\circ}C$, mainly due to the difference in solidification volume change between camphene and TBA. The compressive strength of the sintered bodies was found generally to be dependent, in an inverse manner, on the porosity, which was mainly determined by the processing conditions. After sintering at $1300{\sim}1500^{\circ}C$ with 30~50 wt% solid loading, the resulting mullite ceramics showed porosity and compressive strength values in ranges of 83.8~43.1% and 3.7~206.8 MPa, respectively.

액상-환원법으로 합성된 Cu 분말의 특성에 미치는 분산제의 영향

김용이,김태완,박홍채,윤석영,Kim, Yong-Yee,Kim, Tea-Wan,Park, Hong-Chae,Yoon, Seog-Young 한국재료학회 2007 한국재료학회지 Vol.17 No.1

Ultra-fine Copper powder for a conductive paste in electric-electronic field have been synthesized by chemical reduction of aqueous $CuSO_4$ with hydrazine hydrate $(N_2H_4{\cdot}H_2O)$ as a reductor. The effect of reaction conditions such as dispersant and reaction temperature on the particle size and shape for the prepared Cu powders was investigated by means of XRD, SEM, TEM and TGA. Experiments showed that type of dispersant and reaction temperature were affected on the particle size and morphology of the copper powder. When the carboxymethyl cellulose (CMC) was added as a dispersant the relative mono-dispersed and spherical Cu powder was obtained. Cu powders with particle size of approximately 140nm and narrow particle size distribution were obtained from 0.3M $CuSO_4$ with adding of 0.03M CMC and 40ml $N_2H_4{\cdot}H_2O$ at a reaction temperature of $70^{\circ}C$.

생체유사액 침적에 따른 표면 처리된 titanium plate에 아파타이트 형성

이창훈,진형호,박홍채,윤석영,Lee, Chang-Hoon,Jin, Hyeng-Ho,Park, Hong-Chae,Yoon, Seog-Young 한국결정성장학회 2009 한국결정성장학회지 Vol.19 No.1

생체모방법을 이용하여 표면 처리된 titanium plates 표면에 아파타이트 형성에 관하여 조사하였다. 표면 처리방법으로는 우선, titanium plate 표면에 titanium oxide층을 형성시키기 위하여 열처리온도를 $400^{\circ}C$, $600^{\circ}C$, 그리고 $800^{\circ}C$에서 전기로에서 5시간 유지하였으며, 열처리된 titanium plates 1 M를 수산화나트늄 용액에 침전시켜 표면을 화학적으로 처리하였다. 생체모방법으로 titanium plates 표면에 아파타이트를 형성시키기 위하여 표면처리된 titanium plates 를 Kokubo's recipe에 의하여 제조된 생체유사액(SBF)에 침적시켰다. SBF 용액에 1주와 3주기간 동안 침적시킨 후, 표면처리를 달리한 titanium plates 표면에 형성된 코팅층을 서로 비교 분석하였다. The purpose of this study was to investigate the formation of apatite layer on two different titanium substrate treated with biomimetic method, Titanium plates were heat-treated at different temperatures of $400^{\circ}C$, $600^{\circ}C$, and $800^{\circ}C$ for 5 h in air atmosphere, And then, that plates were chemically treated with an alkali solution of 1 M sodium hydroxide (NaOH), The pre-treated titanium plates were soaked in the simulated body fluid (SBF) of Kokubo's recipe, After soaking for 7 days and 21 days in SBF, the coated layers formed on the titanium plates were characterized and compared with the morphology and chemical composition, The apatite formation was more activated on the titanium plates chemically treated with NaOH compared with the only heat-treated titanium plates.