PRAM을 위한 (GeTe)_x(Sb₂Te₃) (x=0.5, 1, 2, 8) 박막의 물성 및 상변환 특성 연구

김성원,송기호,이현용,Kim, Sung-Won,Song, Ki-Ho,Lee, Hyun-Yong 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.7

In this work, we report several experimental data capable of evaluating the phase transformation characteristics of GeSbTe pseudobinary thin films comprehensively utilized as phase change materials. The phase transformation of the GeSbTe thin films was confirmed by XRD measurement from amorphous to hexagonal structure via fee structure except for $Ge_8Sb_2Te_{11}$. In addition, X-ray photoelectron spectra analysis revealed to weaken Ge-Te bond for $Ge_2Sb_2Te_5$ and to strengthen the bonds of all elements for $Ge_8Sb_2Te_{11}$ during the amorphous to crystalline transition. The values of optical energy gap $(E_{OP})$ were around 0.71 and 0.50 eV and the slopes of absorption in extended region (B) were ${\sim}5.1{\times}10^5$ and ${\sim}10{\times}10^5cm^{-1}{\cdot}V^{-1}$ for the amorphous and fcc-crystalline structures, respectively. Finally, the kinetics of amorphous-to-crystalline phase change on the GeSbTe films was characterized using a nano-pulse scanner with 658-nm laser diode (power; $1{\sim}17$ mW, pulse duration; $10{\sim}460$ ns).

Ag-첨가 Ge₂Sb₂Te₅ 박막의 물성 및 고속 결정화

김성원,송기호,이현용,Kim, Sung-Won,Song, Ki-Ho,Lee, Hyun-Yong 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.7

We report several experimental data capable of evaluating the amorphous-to-crystalline (a-c) phase transformation in $(Ag)_x(Ge_2Sb_2Te_5)_{1-x}$ (x = 0, 0.05, 0.1) thin films prepared by a thermal evaporation. The isothermal a-c structural phase changes were evaluated by XRD, and the optical transmittance was measured in the wavelength range of $800{\sim}3000$ nm using a UV-vis-IR spectrophotometer. A speed of the a-c transition was evaluated by detecting the reflection response signals using a nano-pulse scanner with 658 nm laser diode (power P = $1{\sim}17$ mW, pulse duration t = $10{\sim}460$ ns). The surface morphology and roughness of the films were imaged by AFM. It was found that the crystallization speed was so enhanced with an increase of Ag content. While the sheet resistance of c-phase $(Ag)_x(Ge_2Sb_2Te_5)_{1-x}$ was similar to that of c-phase $Ge_2Sb_2Te_5$ (i.e., $R_c{\sim}10{\Omega}/{\square}$), the sheet resistance of a-phase $(Ag)_x(Ge_2Sb_2Te_5)_{1-x}$ was found to be lager than that of a-phase $Ge_2Sb_2Te_5$, $R_a{\sim}5{\times}10^6{\Omega}{/\square}$. For example, the ratios of $R_a/R_c$ for $Ge_2Sb_2Te_5$ and $(Ag)_{0.1}(Ge_2Sb_2Te_5)_{0.9}$ were approximately $5{\times}10^5$ and $5{\times}10^6$, respectively.

비금속 포스트 코어가 전부도재관에 미치는 광학적인 영향

김성원,조인호,임주환,임헌송,Kim Sung-Won,Cho In-Ho,Lim Ju-Hwan,Lim Heon-Song 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.5

Recently as the esthetic concerns about dental prosthesis have been increased, the nonmetallic post and core systems have been introduced clinically to improve the color and the low optical transmittance of conventional casting metal post and core systems. The purpose of this study was to compare and analyze the optical transmittance and the shade changes of all-ceramic crowns with two nonmetallic post and core systems. The experimental groups were classified as follows : Total 27 specimens(9 samples in each group) were evaluated. Group I : Natural teeth as a control group Group II : CosmoPost and $Empress^{(R)}$ core (Ivoclar-Vivadent, Liechtenstein) Group III : $LIGHT-POST^{TM}$ and $LIGHT-CORE^{TM}$ (Bisco, U.S.A.) In all group, all-ceramic crowns were fabricated with the same shade of IPS $Empress^{(R)}$ II (Ivoclar-Vivadent, Liechtenstein) after abutment preparation, and then two kinds of spectrophotometers, UV 3101 PC (Shimadzu, Japan) and CM 503i (Minolta Co. Ltd. Japan), were used to measure the optical transmittance and the color value. The following results were obtained : 1. The optical transmittance of each group without all-ceramic crowns, was siginificantly decreased in order of Group III, I and II (p<0.05). 2. The optical transmittance of each group with all-ceramic crowns cemented, were siginificantly decreased in order of Group I, II and III (p<0.05). 3. In comparison with the shade of all-ceramic crowns, there were no significant differences between groups regardless of the cementation. 4. In comparison with the shade changes in each group after the cementation of all-ceramic crowns, there were no significant differences between groups. From the above results, it is thought that the selection among materials used in this study doesn't influence greatly the esthetic restoration, because the differences of optical transmittance were so small that those were clinically insignificant.

다중 이동객체 기법을 이용한 효율적인 USN 통합시스템 개발

김성원 ( Sung-won Kim ),백성진 ( Sung-jin Baek ),박선미 ( Sun-mi Park ),송은하 ( Eun-ha Song ),정영식 ( Young-sik Jeong ) 한국정보처리학회 2009 한국정보처리학회 학술대회논문집 Vol.16 No.2

USN 은 저전력 무선 네트워크와 마이크로 센서를 결합하여 환경이나 상황을 인지하고 모니터링을 통해 수집된 정보를 사람에게 전달 하는 기술로, 연구를 위해 다양한 시뮬레이터가 개발되었다. 그러나 기존의 시뮬레이터는 패킷 검증을 위해 설계되고 개발되어 센서의 탐지 동작이 터미널 노드에서 임의로 발생 시키는 한계점을 가지고 있었다. 본 논문에서 제안하는 CROWD 는 이동 객체 기법을 이용하여, 센서의 동적 동작을 보장하고, 노드의 수명 예측, 에너지 소모 효율의 통계, 노드 배치의 변화에 따른 에너지 소모량 변화를 측정한다.

철도 노반 구축물의 광섬유 센서를 활용한 보안시스템에 관한 연구

김성원(Kim Sung Won),송억영(Song Oak Young),배윤(Bae Yoon),황성만(Hwang Sung Man) 한국철도학회 2004 한국철도학회 학술발표대회논문집 Vol.- No.-

The security system using optical fiber is a system, circulating infrared rays laser pulse on the optical fiber which is attached on the security fence to prevent invasion, which can show invasion position with visible and audible signal on the situation monitor if an invader cut or pull the security fence with minuteness of 10m. The optical fiber can be also applied for the bed structure stability monitoring system of high speed train as well as security system. To apply this system for high speed railroad bed structures, this system will give an alarm if it detect excessive tension, shrinkage, deflection which is beyond the limit of structure, that will prevent serious railroad accident. In this paper, we like to propose that applying this system for security and structure stability can improve confidence and stability on operation of railways.

수변완충지대의 효율적 조성을 위한 연구

김성원 ( Sung Won Kim ),최이송 ( I Song Choi ),우효섭 ( Hyo Seop Woo ),오종민 ( Jong Min Oh ) 한국물환경학회 2007 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2007 No.-

비점오염저감을 위한 수변완충지대의 적정 설계

김성원 ( Sung Won Kim ),최이송 ( I Song Choi ),오종민 ( Jong Min Oh ) 한국환경영향평가학회 2008 환경영향평가 Vol.17 No.1

중학생의 과학 상상글쓰기 활동을 통한 상상물 제시 특성

김영실(Kim Young sil),정지현(Jeong Ji hyeon),허송이(Heo Song yi),이지선(Lee Ji sun),김성원(Kim Sung Won) 학습자중심교과교육학회 2015 학습자중심교과교육연구 Vol.15 No.7

본 연구에서는 중학교 2학년 학생 14명을 연구 대상자로 하여 과학 상상글쓰기 활동을 수행하였다. 학생들은 ‘반대로 상상하기’, ‘확대축소 상상하기’, ‘법칙 바꿔 상상하기’, ‘있고 없게 상상하기’의 네 가지의 상상글쓰기 활동을 통해 과학적 상상 력을 발현하도록 하였다. 이 활동을 통해 학생들은 다양하게 상상하여 여러 사물이 나 현상을 제시하였는데 몇 가지 특성들을 보여주고 있다. 학생들은 상상 글쓰기 활 동 수행 중 여러 상상물을 제시하면서, 의미 없는 순서로 상상을 나열하거나(단순 나열), 의미 있는 순서로 확장시키기도 하고(의미 확장), 상상을 제시한 순서가 비약 적이거나 직관적인 형태로 제시하기도 하는(직관적 상상) 세 가지의 특성을 보여주 었다. 먼저 ‘단순 나열형’은 상상물을 제시한 순서가 의미가 없으며 보통 과학적 개 념의 특징과 역할을 상기한 후 각각의 역할이나 특성을 조금씩 변화시키며 상상하 였으며, 키워드로 나열하거나 번호를 매겨 적는 등 특징을 보였다. ‘의미 확장형’은 단순히 상상물을 나열하는 것에서 더 나아가 각각의 상상물을 제시하는 순서가 의 미가 있다. 마지막으로 ‘직관적 상상형’은 흐름과 순서에 상관없이 비약적이거나 직 관적으로 상상하여 상상물을 제시한다. This study has a purpose to analyze scientific imaginations of middle school students through their writing skills. Scientific imagination means the ability to create new troubleshooting solution, which is un-experienced situation or phenomenon through their logical basis of scientific knowledge and experiences. In order to find out the characteristics in writing imaginative matters or phenomena, 14 members of 8th grade students are selected as subjects of the study, and activity models are developed to analyze for those activities. There are four types of activities; Imagine something conversely, imagine enlargement and reduction, imagine changed law, and imagine of with or without. Results of the study are analyzed for both each student and each activity. Only ten students are selected to observe whether their scientific imaginations are expressed or not. There are three types of imagining in science context writing: Simple listing, Meaning expanding, and Intuitive imagining. ‘Simple listing’ type of the students tends to present their imaginations in random orders, and they usually imagine scientific characteristics and role with gradual change after observing original scientific roles and characteristics. Moreover, they tend to list by keywords or numbers. It is one of the required conditions to list an amount of imagination for superb imagination. ‘Meaning expanding’ type of the students tends to not only list their imagination but also list that in order. It means that students imagine something in a variety of enlarged range and they could expand scope from self-centered. ‘Intuitive imagining’ type of the students tends to imagine intuitively and rapidly in any order.

호흡기질환 환자로부터 분리된 Mycoplasma pneumoniae의 tetracycline과 erythromycin에 대한 저항성 변이

장명웅,박인달,김광혁,송갑영,김성원,Chang Myung-Woong,Park In-Dal,Kim Kwang-Hyuk,Song Gap-Young,Kim Sung-Won 한국생명과학회 2005 생명과학회지 Vol.15 No.6

2002년 2월부터 2005년 4월까지 호흡기질환 환자로부터 분리된 M. pneumeniae 123 균주의 tetracycline과 erythromycin에 대한 MIC 범위는 각각 $0.5\~1.0$, and $0.5\~512{\mu}/ml$ 이었다. 분리된 M. pneumoniae 123 균주에서 plasmid DNA는 확인되지 않았다. 분리된 M. pneumoniae 123 균주 중에서 57($46.3\%$) 균주가 tetracycline에 저항성인 tetM유전자를 가지고 있었으며, 235 rRNA domain V에 erythromycin에 저항성 변이를 일으킨 균주가 60($48.8\%$)이었다. erythromycin에 저항성 변이를 일으키지 않은 63균주 중에서 tetM 유전자를 가지고 있는 균주는 36($57.1\%$)이었으며, erythromycin에 저항성 변이를 일으킨 60균주 중에서 21($35.0\%$ 균주가 tetM 유전자를 가지고 있었다. 본 연구로써 국내에서 tetracycline과 erythromycin에 대한 저항성 M. pneumoniae 균주의 분리율이 외국에 비하여 높으며, M. pneumoniae 감염의 치료에 erythromycin이 일차 선택제가 될 수 없으므로 이에 대한 범국가적 조사가 필요하다고 생각된다. One hundred and twenty three strains of Mycoplasma pneumoniae were isolated from patients with respiratory diseases from February 2002 to April 2005 in Busan, Korea. The MICs of tetracycline and erythromycin up to $90\%$ of the 123 M. pneumoniae isolates tested were $0.5\~1.0$, and $0.5\~512{\mu}/ml$, respectively. Plasmid DNA was not isolated from all of the M. pneumoniae isolates. Out of 323 strains of M. pneumoniae, 57 ($46.3\%$) stains contain tetM gene on their chromosomal DNA, and 60 ($48.8\%$) strains were mutated in domain V of 23S rRNA for erythromycin resistance. Out of 63 strains of M. pneumoniae which were not mutated in domain V of 235 rRNA for erythromycin resistance, 36 ($57.1\%$) strains contained tetM gene, and out of 60 strains of M. pneumoniae which were mutated in domain V of 23S rRNA for erythromycin resistance, 21 ($35.0\%$) strains contained tetM gene. These results suggest that the isolation rate of erythromycin and tetracycline resistant M. pneumoniae is higher than those of other countries, and erythromycin and tetracycline are not first choice drug for M. pneumoniae infection in Korea, and it need confirm by a nationwide surveilance of antimicrobial resistance.

2000년 이후 원전 증기발생기 전열관의 누설사건 분석

송명호(Myung Ho Song),김성원(Sung Won Kim),김대근(Dae Geun Kim) 한국비파괴검사학회 2023 한국비파괴검사학회 춘계학술대회 초록집 Vol.2023 No.5