Atomistic Simulation of Hypothetical Silicon Nanotubes under Tension

Ki Ryang Byun,Jeong Won Kang,Ho Jung Hwang 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.5

The responses of hypothetical silicon nanotubes under axial tensile forces have been investigated using an atomistic simulation based on the Terso potential. A tension, proportional to the deformation within Hooke's law, eventually led to a breaking of the silicon nanotubes. As the diameter of silicon nanotubes increased, the ultimate strength linearly increased. However, the force per atom at the breaking of silicon nanotubes was almost constant irrespective of the diameter of the silicon nanotubes. The behaviors of the elastic energy of silicon nanotubes with strain were similar with those of carbon nanotubes and the responses of silicon nanotubes under axial tension were similar with those of carbon nanotubes under axial tension, except for quantitative values, because the structure of silicon nanotubes used in this study was identical with that of carbon nanotubes. The eective strain energy constant of the silicon nanotubes was less than half of that of carbon nanotubes, and the stiness of the silicon nanotubes was much lower than that of carbon nanotubes, and these implied diculty with the formation and application of silicon nanotubes. When the parameters of silicon nanotubes are properly chosen (Young's modulus, eective strain constant, diameter, lattice constant, and strains), the maximum strains, ultimate strengths, and elastic energy at which the breaking events of silicon nanotubes occur could be estimated by using the equations in this work.? ?

질화붕소 나노피포드에 기반한 나노분자 메모리 시스템에 관한 연구

변기량(Ki Ryang Byun),강정원(Jeong Won Kang),최원영(Won Young Choi),황호정(Ho Jung Hwang) 한국진공학회(ASCT) 2005 Applied Science and Convergence Technology Vol.14 No.1

분자 위치제어 메모리 시스템에 대하여 고전적인 분자동역학을 이용하여 결합에너지 및 다양한 외부전기장의 형태에 따른 셔틀 풀러렌 동작에 관하여 연구하였다. 단일 나노피포드 형(single-nanopeapod type)은 질화붕소 나노튜브(boron-nitride nanotube) 속에 세 개의 엔도풀러렌(endo-fullerene)과 양쪽 끝에 구리 전극이 채워져 있는 구조를 갖고 있는 구조를 갖고 있다. 결론적으로, 분자동역학 시뮬레이션 결과로부터 이 나노메모리 시스템은 비휘발성임을 알 수 있었다. 안정적인 bit 변화를 위해서는 단일 나노피포드 형은 0.1eV/Å 외부전기장이 필요로 함을 알 수 있었다. Bucky shuttle memory systems were investigated by the classical molecular dynamics(MD) simulations. Energetics and operating response of the shuttle-memory-elements were examined by MD simulations of the C_(60) shuttle in the nanomemory systems under various external force fields. Single-nanopeapod type was consisting of three fullerenes encapsulated in (l0, 10) boron-nitride nanotube and filled Cu electrode. Studied systems could be applied to nonvolatile memory. MD simulation results showed that the stable bit flops could be achieved from the external force fields of 0.1 eV/Å for single-nanopeapod type.

經濟成長과 社會 및 意識構造의 變化

邊禹亮 단국대학교 법정대학 지역개발학과 1982 地域開發論叢 Vol.3-4 No.-

대학수학능력시험 도입후의 고교교육 변화에 관한 연구

박병량,변영계,한대동,성병창 교육연구소 1994 敎育硏究 Vol.4 No.1

Under the current school system in which secondary schools aim at the preparation for college entrance, the college entrance examination has a crucial impact on high school education. The former college entrance examination has been accused of causing many problems in high school education such as training students, in a recital mode, by giving fragmentary knowledges and skills picked up by teachers largely for the college entrance emanination. Under the examination system students were not recommended either in school or at home to pursue their own interests and concerns which are supposed to enhance higher order thinking including creativity. In order to reform this change-resisting high school education a new type of college entrance examination called College Scholastic Aptitude Test (CSAT, hereafter) replaced the former one in 1990 in the worldwide tide of educational reform toward the quality education. This study is to examine whether and/or to what extent the newly introduced CSAT has brougght changes to high school education. This study began with two concrete research problems. First, to what degree did the CSAT affect high school students particularly in the areas of attitudes toward school, classroom learning and instruction, and study habits? This refers to personal effects separated from school education. Second, to what extent did the CSAT make changes in high school education? This refers to institutional effects. As a survey, this study collected questionnaire data from 1,600 male and female high school third graders from 33 high schools locatedin Pusan City and its surrounding KyungNam-Do province. The CSAT was firstly introduced in 1990 when the survey respondents were then high school freshmen. The sample method is a systematic cluster random sample. After schools had been randomly selected about 60 students(2 classes) were sampled from each school. The questionnaire consisted of questions asking largely whether any changes were made in the areas such as individual student's studying strategies and their perceptions of schooling. The students' responses were analyzed according to concrete research problems using appropriate statistical methods. The research results are summarized as follows. First, according to students' responses they evaluated that CSAT was somewhat successful in measuring higher order thinking and somewhat conducive to lessening social problems cuased by excessively competitive high-cost private lessons. The new exam, however, unexpectedly did not have affirmative effects on such areas as: undesirable operation of high school; measurement of learning ability; selection of college qualifiers; and test item difficulty and discrimination. Second, the effects of CSAT on school-based tests were found to be both slightly positive and negative. For the positive side of the effects, the test content was not confined to textbooks but taken either from other non-text sources or from what was taught in classrooms beside textbooks; in solving the test questions not only correct answers were not required but also the problem-solving processess were also emphasized in schools. In following areas, however, there were almost no changes made: the dominance of multiple-choice test items; anxiety of testers; the utilization of test results for own learning improvement; and the frequent school testing. Third, since the introduction of CSAT there have been almost no improvements in school organizational practices, management, and climates such as; extracurricular activities, communications with teachers, guidance and discipline, teachers' expectations of students, grouping of students according to ability and talent, and friendship among classmates. One exception was that classroom climate has become somewhat open and democratic than before. Fourth, with regard to classroom activities some improvements have been detected. The classroom instruction has been somewhat changed into one emphasizing higher order thinking. It was revealed through teachers' efforts to employ new teaching methods and to carry out curriculum in a regular basis, to try to upgrade expectations of students, and to make classroom learning more explorative. On the other hand, in other areas of classroom activities it was hard to find any noticeable improvements. Finally, it was the area of individual student's studying methods and attitudes that the most noticeable changes were found since the introduction of CSAT. To mention some of them, the dependency on private lessons and private academic institutes was much lessened; the learning materials were varied beside school textbooks; the students' autonomy has been increased in the area of learning need and motivations, studying strategy from memorizing to understanding, and selecting educational or occupational careers based on one's own character and talent. As a result, the introduction of CSAT seems to give student more confidence in studying and learning. Compared to these changes in individual-based studying attitudes, perceptions and learning methods connected to schooling did not change noticeably. This contrasting finding is in a sense a main point of this study. All in all, and in short, the introduction of the new College Scholastic Aptitude Test (CSAT) were somewhat effective in changing individual students' studying or learning attitudes, methods, and strategies in preparation for college entrance, but it was found to be unexpectedly ineffective in improving institutionally school organizational practices, instructional methods, guidance and disciplines, curricular implementation, and other school management and operations. This result reminds us a fact that and educational policy could not be easily rooted in the practical soil.

Nanomechanical Properties of a Suspended Ultrathin Carbon Nanoribbon

강정원,Ki Ryang Byun,황호정,이준하,Hoong Joo Lee,Oh-Keun Kwon 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1

A carbon nanoribbon was investigated using atomistic simulations based on the Tersoff-Brenner potential function. The nanoribbon obtained from a compressed (5, 5) carbon nanotube had a cross-sectional binocular telescope structure composed of both sp2 and sp3 bonds. One carbon atom per ten carbon atoms had an sp3 bond. For the optimized structures, the residual forces on the nanoribbon were three-orders of magnitude higher than that on the nanotube, and the lattice constant of the nanoribbon was 0.0624 °A higher than that of the nanotube along the tube axis. The Young’s modulus of the nanoribbon was the same as that of the nanotube whereas the critical strain of the nanoribbon was significantly lower than that of the nanotube because the residual stresses on the nanoribbon were much higher than those on the nanotube. The tensile force curve vs. the strain of the nanotube was slightly higher than that of the nanoribbon.

A nanoscale field effect data storage of bipolar endo-fullerenesshuttle device

황호정,Ki Ryang Byun,Ju Yul Lee,Jeong Won Kang 한국물리학회 2005 Current Applied Physics Vol.5 No.6

We investigated the internal dynamics of an electro-uid shuttle memory element, consisting of K+@C 60 and F. @C 60 encapsu-lated in a C640 nanocapsule. Energetics and operating responses of bipolarendo-fullerenes shuttle memory device, (K+@C 60F. @C 60)@C 640, were examined by classical molecular dynamics simulations under the external force flelds..

2종의 임플란트 내부결합구조체에 따른 치조골상 유한요소응력 분석

변욱(Ook Byun),정다운(Da-Un Jung),한인혜(In-Hae Han),김성량(Seong-Ryang Kim),이창희(Chang-Hee Lee) 대한턱관절교합학회 2013 구강회복응용과학지 Vol.29 No.3

탄소 나노튜브의 길이변화에 따른 물리적 특성에 관한 이론적 연구

문원하,변기량,황호정 중앙대학교 기술과학연구소 2001 기술과학연구소 논문집 Vol.31 No.-

본 연구에서는 나노 단위의 소자개발을 위하여 (6, 6) 탄소 나노튜브의 유한길이에 따른 물리적 특성에 관해 알아보았다. 먼저 브레너 전위식을 이용하여 모자가 씌워진 탄소 나노튜브의 최적화된 구조를 얻어내었다. 그후 탄소 나노튜브의 최적화된 구조를 가지고 TBMD 시뮬레이션을 수행하였다. TBMD 결과, 에너지 밴드갭은 길이에 따라 반비례하는 것을 알 수 있으며 특히 길이가 20 이하인 경우 탄소와 탄소간의 나타나는 π 결합의 영향으로 인하여 길이에 따라 에너지 밴드갭이 민감한 변화를 보이며 진동함을 알 수 있다. 여기서 (6, 6) 탄소 나노튜브의 에너지 배드갭은 0.3∼2.5 eV 정도임을 알 수 있다. The electronic properties of Carbon Nanotube(CNT) are currently the focus of considerable interest. In this paper, the electronic properties of finite length effect in CNT for carbon nano-scale device is presented. To Calculate the electronic properties of CNT, Empirical potential method (the extended Brenner potential for C-Si-H) for carbon and Tight Binding molecular dynamic (TBMD) simulation are used. As a result of study, we have known that the value of the band gap decreases with increasing the length of the tube. The energy band gap of (6,6) armchair CNT have the ranges between 0.3 eV and 2.5 eV. Also, our result are in agreements with the result of the other computational techniques.

노인의 지혜가 성공적 노화와 삶의 만족도에 미치는 영향

김은량 ( Kim Eun Ryang ),변애경 ( Byun Ae Kyoung ) 아시아문화학술원 2017 인문사회 21 Vol.8 No.3

본 연구의 목적은 노인의 지혜가 성공적 노화와 삶의 만족도와의 관련성을 파악하고, 노인의 지혜가 성공적 노화와 삶의 만족도를 어느 정도 설명하는지를 파악하여, 노인상담의 치료적 개입에 도움을 주고자 한다. 이를 위해 2015년 10월 5일부터 2주간 경기, 인천 지역에 위치한 3곳의 노인 복지관과 종교단체를 중심으로 배부하여 최종 305부의 설문지를 최종분석에 사용하였다. SPSS 18.0 프로그램을 사용하여 노인의 개인변인에 따라 지혜, 성공적 노화, 삶의 만족도의 차이를 알아보기 위해 t검증을 실시하였고, 노인의 지혜가 성공적 노화, 삶의 만족도에 유의미한 영향을 미치는지를 알기 위해 단순회귀분석과 단계적 중다회귀분석을 실시하였다. 그 결과는 다음과 같다. 첫째, 지혜의 차이를 보이는 인구학적 개인 변인은 여성이, 종교가 있을수록, 경제적 수준이 높을수록, 직업이 있을수록 노인의 지혜점수가 높게 나타났다. 둘째, 노인의 지혜가 높을수록 성공적으로 노화를 인식하였고, 삶의 만족도도 높게 나타났다. 셋째, 노인의 지혜는 성공적 노화를 68%를 설명해 주었고, 삶의 만족도는 17.2%를 설명하였다. 따라서 본 연구에서는 지혜가 노화 과정에 지대한 영향을 미친다는 것을 경험적으로 밝힘으로써, 자신의 삶을 통합적으로 보게 하는데 필요한 지혜를 상담과 교육장면에서 활용할 수 있도록 하는 근거를 마련했다는데 의의가 있다. The purpose of this research is to figure out how wisdom of the elderly relates to successful aging and life satisfaction, and to identify how much the wisdom of the elderly explain its successful aging and life satisfaction, so therefore, therapeutic interventions can be put in to action to help the elderly counselling. For the reason that, from October, 5th 2015, for about two weeks, this research used the total of 320 surveys that were distributed mainly to region like Gyeonggi, and Incheon`s elderly welfare and religious organizations towards our final analysis. This research used the SPSS 18.0 program and to find out the differences between the successful aging and life satisfaction depending on the individual factors of the elderly`s wisdom, we conducted the t verification. In addition, to know what kind of significant effect on life satisfaction and successful that is carried out by the wisdom of the elderly, this research used a simple regression analysis and stepwise multiple regression analysis to come out with these results. Firstly, personal demographic variables shown the difference between wisdom of a women, as with religion, as with a job, the higher the economic level it showed the higher wisdom scores for the elderly. Secondly, the higher the wisdom of the elderly was, they were more aware of their aging successfully, meaning higher life satisfaction. Lastly, the wisdom of the elderly explained 68% of their successful aging and 17.2% of their life satisfaction. According to these results, its proves that wisdom of the elderly do impact their successful aging and their life satisfaction and lays the basis for their wisdom to integrated look into their own lives to take advantage in consulting and training scenes

Monte Carlo 시뮬레이션을 이용한 이온 주입시의 점결함 분포의 계산

손명식,이준하,변기량,황호정 중앙대학교 기술과학연구소 1995 기술과학연구소 논문집 Vol.25 No.-

이온 주입시의 점결함 분포를 간접적으로 계산하기 위해 단결정 실리콘에서의 3차원 이온 주입 시뮬레이터인 TRICSI (TRansport Ions in Crystal Slilicon) Monte Carlo 코드를 확장하여 Boron 이온 주입시의 에너지와 dose에 따른 불순물(particle) 및 점결함 분포(point defect)를 계산하였다. 결함 분포는 Modified Kinchin-Pease equation을 단결정 실리콘에 적용하여 displacement damage에 의해 발생한 Frenkel Pair(vacancy-interstitial)분포를 계산하였으며 이온 주입시의 웨이퍼 온도에 의한 Frenkel Pair 소멸 효과는 고려하지 않았다. 계산 결과는 3차원 각면으로의 2차원 투영 불순물 농도로 표현하고 주입된 dose와 에너지에 다른 마스크 주입시의 에너지 및 dose 의존성 도펀트 분포와 이에 따른 damage 분포를 이해하는 데 중요한 정보가 될 것으로 기대된다. We extended our ion implantation simulator, TRICSI (TRansport lons in Crystal Slilicon) Monte Carlo(MC) code, and indirectly calculated particle and its generating point defect distributions depending on energy and dose during boron implantation into <100> single0crystal silicon. The point defect distribution of Frenkel Pair(vacancy-interstitial) was abtained by applying the modified Kinchin-Pease equation, which usually uses in MC simulation in amorphous target, to MC simulation in crystalline silicon. We did not considered the annihilation of Frenkel Pairs due to wafer temperature. The calculated results were projected onto each free-dimensional plane, presented as two-dimensional concentration profile on it. The particle concentration profile was presented with typical open mask structure. We expect that these results help understand the dopant and its generating damage distributions depending on energy and dose during boron implantation.