• EDISON SW 활용 경진대회 논문집
• /
• 제2회(2013년)
• /
• pp.1-12
• /
• 2013

그래핀에 대한 이론 연구는 주로 계산이 용이한 코스그레인 (Coarse-grained) 모델을 이용한 분자동역학 시뮬레이션을 토대로 이루어져 왔다. 하지만 그래핀 고분자 복합체, 표면이 개질된 그래핀의 구조 등에 대한 원자 수준의 총체적인 정보는 거시적인 (Macroscopic) 코스그레인 모델을 바탕으로 한 분자동역학 시뮬레이션으로는 얻을 수 없다. 따라서 본 연구에서는 전자구조 계산 및 원자 수준 모델의 Born Oppenheimer Molecular Dynamics를 이용하여 작은 그래핀 분자의 구조 (Structure)와 형태동역학 (Conformational Dynamics)에 대한 정보를 얻고, 이를 바탕으로 한 코스그레인 모델을 구축하였다. 더 나아가 이 코스그레인 모델을 이용하여 전기전도성 네트워크와 고분자-그래핀 복합체의 구조 등에 대해 살펴보고자 한다.

• 한국시스템다이내믹스연구
• /
• 제3권2호
• /
• pp.49-68
• /
• 2002

The intent of this study is to develop system dynamics model for assessment of organizational and human factors in nuclear power plant which can contribute to secure the nuclear safety. Previous studies are classified into two major approaches. One is engineering approach such as ergonomics and probability safety assessment(PSA). The other is social science approach such like sociology, organization theory and psychology. Both have contributed to find organization and human factors and to present guideline to lessen human error in NPP. But, since these methodologies assume that relationship among factors is independent they don't explain the interactions among factors or variables in NPP. To overcome these limits, we have developed system dynamics model which can show cause and effect among factors and quantify organizational and human factors. The model we developed is composed of 16 functions of job process in nuclear power, and shows interactions among various factors which affects employees' productivity and job quality. Handling variables such like degree of leadership, adjustment of number of employee, and workload in each department, users can simulate various situations in nuclear power plant in the organization side. Through simulation, user can get insight to improve safety in plants and to find managerial tools in the organization and human side. Analyzing pattern of variables, users can get knowledge of their organization structure, and understand stands of other departments or employees. Ultimately they can build learning organization to secure optimal safety in nuclear power plant.

• 한국자기공명학회논문지
• /
• 제22권4호
• /
• pp.139-143
• /
• 2018

Short antimicrobial peptide, A4W, have been studied by molecular dynamics (MD) simulation in an explicit dodecylphosphocholine (DPC) micelle. Peptide was aligned with DPC micelle and transferred new peptide-micelle coordinates within the same solvent box using specific micelle topology parameters. After initial energy minimization and equilibration, the conformation and orientation of the peptide were analyzed from trajectories obtained from the RMD (restrained molecular dynamics) or the subsequent free MD. Also, the information of solvation in the backbone and the side chain of the peptide, hydrogen bonding, and the properties of the dynamics were obtained. The results showed that the backbone residues of peptide are either solvated using water or in other case, they relate to hydrogen bonding. These properties could be a critical factor against the insertion mode of interaction. Most of the peptide-micelle interactions come from the hydrophobic interaction between the side chains of peptide and the structural interior of micelle system. The interaction of peptide-micelle, electrostatic potential and hydrogen bonding, between the terminal residues of peptide and the headgroups in micelle were observed. These interactions could be effect on the structure and flexibility of the peptide terminus.

• International Journal of Aeronautical and Space Sciences
• /
• 제8권2호
• /
• pp.89-97
• /
• 2007

COMS(Communication, Oceanography, and Meteorology Satellite) is the first Korean multi-purpose satellite which is planned to be deployed at the altitude of geosynchronous orbit above the Korean peninsular. Noting that COMS is composed of the main BUS structure, two deployable solar panels, one yoke, five reactions wheels, COMS is treated as a collection of 9 bodies and its nonlinear equations of motion are obtained using the multi-body dynamics approach. Also, a computer program is developed to analyze the COMS motion during the various mission phase. Quite often, the equations of motion have to be derived repeatedly to reflect the fact that the spacecraft dynamics change as its configuration, and therefore its degree of freedom varies. However, the equations of motion and simulation software presented in this paper are general enough to represent the COMS dynamics of various configurations with a minimum change in input files. There is no need to derive the equations of motion repeatedly. To show the capability of the simulation program, the spacecraft motion during the solar array partial and full deployment has been simulated and the results are summarized in this paper.

• 한국시스템다이내믹스연구
• /
• 제4권1호
• /
• pp.69-91
• /
• 2003

Using qualitative methods hinged on urban dynamics models, the paper addresses major issues concerned with new administrative capital construction. It tries to summarize the existing debates on new administrative capital construction and reinterpret diverse interacting factors in terms of reinforcing or balancing feedback structure. The paper suggests that understanding up on the dynamic mechanism imbedded in circular causal loop diagrams is the key to set up appropriate proposals and action plans for the new administrative capital, as they would reveal complicated linkages between the Capital Region and the rest, in addition to the urban dynamic of new administrative capital. In the same context, the paper can confirm similar features reflected in the relocation of capital functions at Canberra, Australia and Berlin, Germany. It has paid special attention to the fact that both Australian and German governments altogether stress the positive feedback loops as they have overcome unprecedented political confrontation among rival cities: Basically, they have encouraged gives-and-takes among major stake-holders. These research findings indicate that the future of new administrative capital construction depends on consensus buildings that can accommodate socio-economic and territorial changes between pros and cons. Although further researches and validations are needed, the system approach presented in this paper could assist Korean decision-makers in developing robust and responsive policy initiatives under uncertainties.

• 한국재료학회지
• /
• 제16권2호
• /
• pp.92-98
• /
• 2006

Molecular dynamics simulations were performed to study interface structures between an $Al_2O_3$ crystalline phase and a interface phase of $CaAl_2Si_2O_8$. We calculated atomic structures and excess interface energies in systems with different thicknesses of the interface film. It was found that excess interface energies at first readily decreased with increasing film thickness, but increased for larger thicknesses of more than 2 nm. The excess energies of $Al_2O_3/CaAl_2Si_2O_8$ interfaces exhibit a minimum at a thickness around 1 nm. In this range of film thicknesses, the atoms in the interface film show a short-range ordered structure and slow diffusion rather than the random structure and rapid diffusion expected to an observation of an equilibrium thickness for interface films in ceramics.

• 한국군사과학기술학회지
• /
• 제4권1호
• /
• pp.13-19
• /
• 2001

It is known that displacements, velocities and accelerations of the tractor- trailer type vehicle system in shock & vibration analysis by the flexible-multi-body dynamics including the flexibility of structure are bigger and more repetitive than them by the rigid-multi-body dynamics, and it is necessary to prove above results by the experimental field test. Therefore, in this paper, theoretical analysis by the flexible-multi-body dynamics and experimental field test for a tractor-trailer type vehicle system are conducted and their results are compared with each other. Because of unexpected metal contact and impact in the air coupler part in the field test, some accelerations measured from the experimental field test are bigger than them analyzed from the theoretical analysis, but most accelerations are well coincide with each other in the amplitudes and trends. Thus more refined dynamic analytical models for some special type vehicle systems will be possible in the future.

• Advances in aircraft and spacecraft science
• /
• 제2권3호
• /
• pp.303-328
• /
• 2015

A design methodology is presented to develop the hingeless control surfaces for MAV using adhesively bonded Macro Fiber Composite (MFC) actuators. These actuators have got the capability to deflect the trailing edge surfaces of the wing to attain the required maneuverability, besides achieving the set aerodynamic trim condition. A scheme involving design, analysis, fabrication and testing procedure has been adopted to realize the trailing edge morphing mechanism. The stiffness distribution of the composite MAV wing is tailored such that the induced deflection by piezoelectric actuation is approximately optimized. Through ground testing, the proposed concept has been demonstrated on a typical MAV structure. Electromechanical analysis is performed to evaluate the actuator performance and subsequently aeroelastic and 2D CFD analyses are carried out to see the functional requirements of wing trailing edge surfaces to behave as elevons. Efforts have been made to obtain the performance comparison of conventional control surfaces (elevons) with morphing wing trailing edge surfaces. A significant improvement in lift to drag ratio is noticed with morphed wing configuration in comparison to conventional wing. Further, it has been shown that the morphed wing trailing edge surfaces can be deployed as elevons for aerodynamic trim applications.

• International Journal of Aeronautical and Space Sciences
• /
• 제5권1호
• /
• pp.19-29
• /
• 2004

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 1996년도 정기총회 및 학술발표회
• /
• pp.21-21
• /
• 1996

The hyperthermostable protein, rubredoxin from Pyrococcus furiosus is 53-residue protein with a three-stranded anti-parallel $\beta$-sheet and several loops. To investigate the effect of changes of electrostatic and hydrophobic interactions on the structure and dynamic property of P. furiosus rubredoxin, molecular dynamics simulations in water were performed on three mesophilic rubredoxins, P, furiosus rubresoxin, and 5 mutants of P. furiosus rubredoxin. (omitted)