김천규석으로부터 질화규소의 합성

이홍림,서원선,조덕호,이종민 한국세라믹학회 1987 한국세라믹학회지 Vol.24 No.2

Silicon nitride powders were prepared by the simultaneous reduction and nitridation from powder mixtures of Kim cheon quartzite and carbon (graphite or carbon black) at1400$^{\circ}C$ for 10 hours in nitrogen atmosphere. The effects of the reaction variables on the yield of products and on the ${\alpha}$/${\beta}$ ratio were examined. The average particle size, density, and the ${\alpha}$/${\beta}$ ratio of the obtained si3N4 were 1.0$\mu\textrm{m}$, 3.10g/㎤ and 90/10, respectively. It was found that the Si3N4 powders obtained in this work were comparable to the foreign commercial products.

공침법으로 제조한 $ZrO_2$+3m/o $Y_2O_3$계 분체의 특성(II) : Y-TZP의 기계적 성질 및 미세구조에 미치는 $Al_2O3$와 $Cr_2O_3$의 첨가영향

이홍림,최동근,홍기곤,신현곤 한국세라믹학회 1990 한국세라믹학회지 Vol.27 No.4

The effects of Al2O3 and Cr2O3 addition on the mechanical properties and microstructures of Y-TZP ceramics obtained by co-precipitation method of ZrO2+3m/o Y2O3, following pressureless sintering at 150$0^{\circ}C$ for 2h were investigated. The addition of Al2O3 and Cr2O3 improved the Y-TZP sinterability and the Al2O3 addition showed the better effect on Y-TZP sintering than that of the Cr2O3 addition. The density and microstructure had the better effect on the bending strength of specimen more than stressinduced phase transformation (SIPT) of ZrO2 from tetragonal to monoclinic phase. The hardness of the specimens was found to be depend on the relative density and the fracture toughness of Y-TZP was found to rely on the amount of SIPT. The grian size of Cr2O3-doped Y-TZP was observed to be relatively smaller and had a narrower distribution than that of Al2O3-doped Y-TZP. If decomposition reaction of Cr2O3 can be controlled at high temperatures, it is anticipated that the mechanical properties of Y-TZP can be much improved by the Cr2O3 addition.

알콕사이드로부터 Mullite분말의 합성 및 그 특성

이홍림,함종근 한국세라믹학회 1989 한국세라믹학회지 Vol.26 No.6

A very fine and pure mullite powder of the stoichiometric composition was prepared from aluminium isopropoxide and tetraethylorthosilicate by an alkoxide hydrolysis method using NH4OH as a catalytic agent. The gel powder obtained from the hydrolysis was calcined at 80$0^{\circ}C$ and 125$0^{\circ}C$. The average particle sizes of the powders calcined at 80$0^{\circ}C$ and 125$0^{\circ}C$ were 0.19${\mu}{\textrm}{m}$ and 0.25${\mu}{\textrm}{m}$, respectively. The specific surface areas of the powders calcined at 80$0^{\circ}C$ and 125$0^{\circ}C$ were 114.7$m^2$/g and 20.6$m^2$/g, respectively. The bending strength and fracture toughness of the mullite ceramics sintered at 1$650^{\circ}C$ were 263.1MPa and 2.30MPa.m1/2 respectively.

알콕사이드로부터 AlN분말의 합성 및 분말 특성

이홍림,박세민,조덕호 한국세라믹학회 1989 한국세라믹학회지 Vol.26 No.1

Aluminum hydroxides were prepared by the alkoxide hydrolysis method using Al-isopropoxide as a starting material and NH4OH as a catalytic agent. When Al-isopropoxide was hydrolyzed in a H2O-NH3 system, only Al(OH)3 was obtained over all pH values. However, AlOOH was formed besides Al(OH)3 when Al-isopropoxide was hydrolyzed in a H2O-NH3-isopropyl alcohol system. The AlOOH/Al(OH)3 ratio was increased as the isopropyl alcohol content was increased. The hydroxides, Al(OH)3 and AlOOH, obtained in this study and the commerical products, $\alpha$-Al2O3 and AlOOH were subjected to the carbothermal reduction and nitridation reaction to product AlN powder, using carbon black as a reducing agent under N2 atmosphere at various temperatures. AlN was synthesized from the obtained Al(OH)3 and the commercial AlOOH at 145$0^{\circ}C$, however, synthesized from the obtained AlOOH and the commercial alpha-alumina at 135$0^{\circ}C$. The temperature difference is assumed to be attributed to the reactivity of those powders. AlN powder prepared from the Al-isopropoxide was observed to have the narrower particle size distribution than that prepared from the commercial $\alpha$-Al2O3 or AlOOH.

Al-isopropoxide로부터 제조한 AlN 세라믹스의 기계적 성질과 미세구조에 미치는 산화물 첨가제의 영향

이홍림,황해진 한국세라믹학회 1990 한국세라믹학회지 Vol.27 No.6

In this study, effects of oxide additives on mechanical properties and microstructure of A1N and A1N polytype ceramics were investigated. Fine A1N powder was synthesized by nitriding alumiuim hydroxide prepared from Al-isopropoxide, at 1350$^{\circ}C$ for 10h in N2 atmosphere. By adding 3w/o Y2O3, 0.56w/o CaO, and 10w/o SiO2 to AlN powder, AlN and AlN polytype ceramics were prepared by hot-pressing under the pressure of 30 MPa at 1800$^{\circ}C$ for 1h. AlN ceramics with no additives formed considerable amount of AlON phase, while AlN ceramics doped with Y2O3 or CaO decreased AlON phase and formed Y-Al or Ca-Al oxide compound. AlN+10w/o SiO2(+3w/o Y2O3) composition produced AlON and AlN polytype compound having 21R as a major phase. Room temperature flexural strength of AlN ceramics with no additive was 246MPa, and room temperature flexural strength and critical temperature difference by thermal shock(ΔTc) of AlN ceramics dooped with Y2O3 or CaO were 532MPa/340$^{\circ}C$ and 423MPa/300$^{\circ}C$, respectively. Y2O3 and CaO used as sintering agent played roles of densification and oxygen removal of AlN ceramics, and affected grain growth/grain morphologies of AlN ceramics.

알콕사이드로부터 Si-Al-O-N계 분말합성 II. 알콕사이드로부터 합성한 Si3N4 및 $\beta$-Sialon의 분말 및 소결체의 특성

이홍림,전명철 한국세라믹학회 1989 한국세라믹학회지 Vol.26 No.2

Fine Si-Al-OH coprecipitate powders were prepared from Si- and Al-alkoxides by the hydrolysis method. $\beta$-Sialon powder was obtained from prepared Si-Al-OH coprecipitate by the simultaneous reduction and nitridation method. The syntehsized Sialon powder was pressureless sintered at 175$0^{\circ}C$ for 90 min in N2 atmosphere. The characterization of the Sialon powder was performed with XRD, BET, SEM, TEM and particle size analysis. The sinterability and mechanical properties of sintered bodies were investigated in terms of relative density, M.O.R., fracture toughness, hardness and the morphology of microstructure. The highest values of their mechanical properties were obtained for the $\beta$-Sialon ceramics at Z=1 and those values are as follows : M.O.R., KIC and HV of $\beta$-Sialon ceramics(Z=1) are 499.1 MPa, 5.9MN/m3/2 and 18.7GPa, respectively.

ITU, Internet 도메인 네임 관리개선을 위한 gTLD-MoU회의 개최

이홍림 한국정보통신기술협회 1997 TTA저널 Vol.51 No.-

현행 Internet 도메인 네임(domain name)에 대한 관리체계를 개선하기 위한 gTLD-MoU회의가 4월 29일부터 5월1일까지 스위스 제네바의 ITU본부에서 개최되었다. 현재 미국 독점으로 관리되고 있는 Internet top level domain name의 등록 및 관리체계를 전면적으로 개선하기 위해 개최된 본 회의는 지난해 11월 발족이후 이에 대한 검토작업을 진행해 온 IAHC(Internet International Ad Hoc Committee)의 주관으로 IANA, ISOC, ITU, WIPO를 포함, 전 세계로부터 101개 기관, 126명의 대표가 참석하였으며, 향후 Internet top level domain name의 등록업무 및 관리체계 개선에 관한 세부내용을 담은 양해각서(gTLD-MoU)에 대한 논의와 함께 80개 기관 대표가 서명에 참가한 가운데 gTLD-MoU에 대한 서명식을 가졌다. 한편, gTLD-MoU가 5월 1일로 정식 발효됨에 따라 ITU는 앞으로 gTLD-MoU의 관리기관(depository) 역할을 수행하게 되며, MoU 및 서명자 관리와 관련정보의 유통업무 등을 담당하게 된다.

Y2K 문제에 대한 ITU의 대응

이홍림 한국컴퓨터통신연구회 1998 OSIA Standards & Technology Review Vol.12 No.3

김천규석으로부터 $\alpha$-Sialon의 합성

이홍림,서원선,조덕호,이경원 한국세라믹학회 1987 한국세라믹학회지 Vol.24 No.5

Silicon nitride powder synthesized from Kimcheon quartzite and commercial reagents, AlN and Y2O3 powders were used to prepare the partially and fully stabilized Y-${\alpha}$-Sialon ceramics by the pressureless sintering at 1800$^{\circ}C$ for 2 hours in N2 atmosphere. Good mechanical properties of the prepared Y-${\alpha}$-Sialon ceramics were found over 0.4∼0.6 of the Yttrium solubility range, X, in the equation Yx(Si12-4.5x, Al4.5x)(O1.5x, N16-1.5x). The properties of these prepared Y-${\alpha}$-Sialon ceramics were compared with those prepared in the same way from a commercial Toshiba Si3N4 powder.

한국판 외상 후 증상 검사: 신뢰도와 타당도 검증

이홍림,곽준규 한국상담학회 2004 상담학연구 Vol.5 No.3

The Child and Parents Reports of Post-traumatic Symptoms(CROPS & PROPS) are brief paper and pencil measures of children's post-traumatic symptoms in English with previously demonstrated content validity, criterion validity, internal consistency, and alternate forms test-retest reliability. The present report details the methodology and findings of a Korean version of these measures along with reliability and validity study with 248 Korean high school students and their parents. The translation involved a bilingual Korean who resides in England, an expert rating, and re-translation. Three brief psychological measures were administered concurrently with the Korean version of CROPS and PROPS. Concurrent and discriminant validity were demonstrated as predicted with three subscales(measuring family communication, family cohesion and adaptation, and self-concept); Internal consistency and reliability were supported but factor analysis shows a little different structure. These findings provide additional support for the validity and reliability of the CROPS and PROPS, and for their utility in a Korean population. 아동·청소년용 및 부모용 외상 후 증상 검사(The Child and Parent Reports of Post-traumatic Symptoms: CROPS & PROPS)는 외상(trauma) 후 증상을 진단하는 비교적 간편한 자기보고식 지필검사로서 이미 내용 및 준거타당도, 내적 합치도, 이형 재검사 신뢰도 등이 검증된 도구이다. 본 연구는 이 척도의 한국어판을 제작하여 서울시 소재 한 고등학교 남녀학생에게 실시하여 이도구의 신뢰도와 타당도를 검증했다. 먼저 도구제작을 위해 영어 원본을 번역 후 심리학과 국어교육학 전문가들의 토의를 거쳐 문항을 수정한 후 영어와 한국어를 자유롭게 구사하는 해외 거주 한국인이 이를 영어로 재번역한 것을 원문과 비교하여 보완 수정했다. 이렇게 제작된 두 도구의 타당도 검증을 위한 준거로 외상증상과 관련된 심리검사(의사소통, 가족의 결속력, 자아개념)의 하위척도를 활용했다. 검증결과 Cronbach’s alpha가 CROPS는 .86, PROPS는 .91로 신뢰도는 상당히 높게 나왔고 타당도 준거로 활용한 심리검사와의 변별 타당도도 예상대로 검증되어 한국에서의 이 두 도구의 사용가능성을 지지해준다.