Energy exchange between vibration modes of a graphene nanoflake oscillator: Molecular dynamics study

권오근,김학원,강정원 한국물리학회 2014 Current Applied Physics Vol.14 No.3

We investigated the oscillatory behaviors of a square graphene-nanoflake (GNF) on a rectangular GNF via classical molecular dynamics simulations, and analyzed the energy exchange and the oscillation frequencies for three different modes. The simulation results using a model structure show that the GNF oscillator can be considered as a high frequency oscillator. As its initial velocity increases, its telescoping region increases, then its structural asymmetry along the axis due to own small rotation exerted asymmetric van der Waals (vdW) force on it, and finally, this asymmetric vdW force enhances its rotational motions during its axial translational motions. So the initial kinetic energy of the axial translational motion is changed into the energy of the orthogonal vibrational and the rotational motions. Its resonance frequencies are dependent on the aspect ratio of the bottom rectangular GNF, the difference between the lengths of the GNF oscillator and the bottom rectangular GNF, and the initial velocity.

해외시찰 보고서 - 미국ㆍ일본 신문사의 옴부즈맨제도를 중심으로 -

권오근 언론중재위원회 2003 言論仲裁 Vol.89 No.-

선거보도 심의 사례 분석

권오근 언론중재위원회 2008 言論仲裁 Vol.107 No.-

목단피로부터 항균활성 성분의 분리

권오근,김성환,천병열,박채규,손건호,Kwon, Oh-Geun,Kim, Sung-Hwan,Chun, Byung-Yeol,Park, Chae-Kyu,Son, Kun-Ho 한국생약학회 1999 생약학회지 Vol.30 No.3

To evaluate antimicrobial activity of Moutan cortex the compounds isolated from $CHCl_3$ and EtOAc fractions of Moutan cortex were subjected to eight pathogenic strains. Benzoic acid, witch was identified from the $CHCl_3$ fraction, had MICs with $625{\sim}1,250\;{\mu}g/ml$ against all of the strains tested. Methyl gallate, p-hydroxy benzoic acid, gallic acid and $1,2,3,4,6-penta-O-gallyol-{\beta}-D-glucose$, which were identified from the EtOAc fraction, showed the antimicrobial activity, and the methyl gallate had the widest antimicrobial activity with MICs of $625{\sim}5,000\;{\mu}g/ml$ against all strains tested. p-Hydroxy benzoic acid showed MICs of $1,250{\sim}2,500\;{\mu}g/ml$ against all of the strains tested except C.albicans. Gallic acid had the best antimicrobial activities with MICs against the Shigella dysenteriae and Streptococcus mutans-strains of 78.1 and $312.5\;{\mu}g/ml$, respectively, but not against the C. albicans. And $1,2,3,4,6-penta-O-gallyol-{\beta}-D-glucose$ had the best antimicrobial activitie with MICs against the B. cereus, Staph. epidermidis and C. albicans strains of 39.1, 39.1 and $156.3\;{\mu}g/ml$, respectively, but not against the E. coli and Shig. Dysenteriae.

고농도 불순물 확산 공정을 위한 3차원 시뮬레이션

권오근,이규성,이준하,황호정 대한전자공학회 1995 대한전자공학회 학술대회 Vol.1995 No.1

CMP 공정에서 연마패드 경도에 따른 연마 특성 변화 분자동력학 연구

권오근,최태호,이준하 한국반도체디스플레이기술학회 2013 반도체디스플레이기술학회지 Vol.12 No.1

We investigated the wearable dynamics of diamond spherical abrasive during the substrate surface polishing under the pad compression via classical molecular dynamics modeling. We performed three-dimensional molecular dynamics simulations using the Morse potential functions for the copper substrate and the Tersoff potential function for the diamond abrasive. The pad hardness had a big impact on the wearable dynamics of the abrasive. The moving speed of the abrasive decreased with increasing hardness of the pad. As the hardness decreased, the abrasive was indented into the pad and then the sliding motion of the abrasive was increased. So the pad hardness was greatly influenced on the slide-to-roll ratio as well as the wearable rate.

HEALING for the MENTALLY ILL in the KOREAN CHURCH

권오근 한국복음주의실천신학회 2003 복음과 실천신학 Vol.5 No.-

삽입 가스의 부피 팽창을 이용한 탄소나노튜브 진동기

권오근,Kwon, Oh-Keun 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.12

We investigated a carbon nanotube (CNT) oscillator controlled by the thermal gas expansion using classical molecular dynamics simulations. When the temperature rapidly increased, the force on the CNT oscillator induced by the thermal gas expansion rapidly increased and pushed out the CNT oscillator. As the CNT oscillator extruded from the outer nanotube, the suction force on the CNT oscillator increased by the excess van der Waals(vdW) energy. When the CNT oscillator reached at the maximum extrusion point, the CNT oscillator was encapsulated into the outer nanotube by the suction force. Therefore, the CNT oscillator could be oscillated by both the gas expansion and the excess vdW interaction. As the temperature increased, the amplitude of the CNT oscillator increased. At the high temperatures, the CNT oscillator escaped from the outer nanotube, because the force on the CNT oscillator due to the thermal gas expansion was higher than the suction force due to the excess vdW energy. By the appropriate temperature controls, such as the maximum temperature, the heating rate, and the cooling rate, the CNT oscillator could be operated.

국부 셀 격자 결함 모델을 사용한 극 저 에너지 이온 주입에 관한 연구

권오근,강정원,황호정,Kwon, Oh-Keun,Kang, Jeong-Won,Hwang, Ho-Jung 대한전자공학회 1999 電子工學會論文誌, D Vol.d36 No.7

We have investigated effects of local damage accumulation for ultra-low energy As and B ion implant using highly efficient molecular dynamics(MD) scheme. We simulated ion implantation by MD simulation using recoil ion approximation (RIA) method and local cell damage accumulation (LCDA) model proposed in the paper. Local damage accumulation probability function consisted of deposited energy in a unit cell, implant dose rate, target material, projectile atom, and recoil event number. The simulated results were good agreement with the experimental and other simulated results. The MDRANGE results without damage accumulation were different from SIMS data in the tail region. We also simulated 2 dimensional dopant and damage profiles using the local damage accumulation model and recoil ion approximation method. 본 논문은 극 저 에너지 이온 주입의 원자단위 연구를 위하여 국부 셀 격자결함 축적 모델(local cell damage accumulation model)을 제안하고, 분자 역학 방법(molecular dynamics method)을 사용한 이온 주입 시뮬레이션 결과를 보여주고 있다. 국부 격자 결함 확률 축적 함수는 각 단위 셀에 축적된 에너지, 이온빔 전류, 기판 물질, 주입 이온과 이온 발생 순서 등으로 구성되어 있다. 시뮬레이션 결과는 SIMS 측정치 및 다른 분자 역학 시뮬레이션과 잘 일치한다. 격자결함을 고려하지 않는 MDRANGE는 격자결함으로 인한 채널링 억제 효과가 나타나지 않기 때문에 불순물 분포의 꼬리 부분에서 많은 차이를 보였다. 또한 국부 격자결함 축적 모델을 사용한 경우와 이를 고려하지 않는 경우의 불순물과 격자결함에 관한 2차원 분포를 계산하여 국부적으로 축적된 격자결함이 이온의 진행에 큰 영향을 미치는 것으로 나타났다.

풀러렌 셔틀 소자로 그래핀 나노리본 트렌치 응용에 관한 분자동력학 시뮬레이션 연구

권오근,강정원 사단법인 인문사회과학기술융합학회 2018 예술인문사회융합멀티미디어논문지 Vol.8 No.1

We investigated the position controlling C60 fullerene encapsulated into a graphene-nanoribbon trench via classical molecular dynamics simulations. The graphene-nanoribbon trench can provide nanoscale empty spaces, and a C60 encapsulated therein can be considered as media for a nanoelectromechanical shuttle device. The classical molecular dynamics simulations presented here provide information on the potential application of a graphene-nanoribbon trench in a C60 shuttle device. Driving forces applied to C60 resulted in its motion toward the edges of the graphene-nanoribbon trench, the suction forces induced at both edges were balanced with the driving forces, and finally, the C60 fullerene gradually settled on the edges of the graphene-nanoribbon trench after several oscillations. The results of the present simulation suggest the importance of graphene-nanoribbon trenches encapsulating fullerenes in a wide range of applications in the field of nanotechnology. 최근 그래핀을 이용한 나노전자소자에 대한 많은 연구들이 다양한 분야에서 활발하게 이루어지고 있다. 본 연구에서는 분자동력학 시뮬레이션 방법을 사용하여 그래핀 나노리본 트렌치 구조를 이용한 풀러렌 분자 셔틀 소자로의 활용 가능성에 대하여 연구하였다. 그래핀 나노리본 트렌치 구조는 그 나노미터 규모의 분자 저장이 가능한 공간을 만들 수 있어, 이 공간을 활용하여 나노전기전자소자를 제작할 수 있는 가능성을 열어준다. 그래핀 나노리본 트렌치로 흡수된 풀러렌 분자는 외부 작용력의 방향에 따라서 그 위치를 그래핀 나노리본 트렌치 내부에서 조정할 수 있게 되기 때문에, 이를 이용하여 그래핀 나노리본 트랜체 내부에서 플러렌의 위치 조정으로 디지털 정보를 저장할 수 있다. 풀러렌 분자가 그래핀 나노리본 트렌치 내부에서 고랑을 따라서 이동과정에서 다양한 운동에너지 역학이 작용되는 것을 살펴보았다. 본 연구에서는 그래핀 나노리본 트렌치에 흡수된 풀러렌 분자는 나노전지전자소자의 오실레이터, 정보저장소자, 센서 등 다양한 첨단 분야에서 활용가능하다는 것을 연구하였다.