Hsien-Chie Cheng¹, Chun-Hung Wu², Yang-Lun Liu², Wen-Hwa Chen²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.3, pp. 65-66, 2009, DOI:10.3970/icces.2009.011.065

Abstract This study attempts to explore the thermal effect on the vibrational behaviors of single-walled carbon nanotube (SWCNT) using both a constant temperature molecular dynamics (MD) simulation that incorporates a Nosé-Hoover thermostat and a modified molecular structure mechanics (MMSM) model. The MD simulation is combined with a Nosé-Hoover thermostat, which controls the temperature of the system by an additional thermal reservoir. On the other hand, the MMSM model adopts equivalent beam elements and spring elements to simulate the bonding and non-bonding interactions between atoms, respectively, where the effect of temperatures can be also taken into account… More >

Tei-Chen Chen^1,2, Heng-Chieh Wang¹, Shu-Fan Wu¹, Yen-Hung Lin¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.4, pp. 247-262, 2009, DOI:10.3970/icces.2009.009.247

Abstract Mechanical properties of materials in the micro- and nano-meter scale have been successfully obtained by using the indentation technique. Up to now, large-scale atomistic models to simulate the experimental condition, however, still remain computationally demanding. In this article, a simple and accurate method is proposed to derive the intermolecular potential functions of coarse-grained molecular dynamics (CGMD) suitable for various single crystalline materials. This CGMD technique is then provided to simulate nano-indentation process to verify its accuracy and reliability. Simulation results evaluated by CGMD approach are obtained and compared to those predicted by MD. It is More >

Youngmin Lee, Jae Shin Park, Seyoung Im

The International Conference on Computational & Experimental Engineering and Sciences, Vol.10, No.2, pp. 51-52, 2009, DOI:10.3970/icces.2009.010.051

Abstract We study energetics and mobility of dislocations in silicon crystal in atomistic scale. The electronic structure of silicon affects its dynamics, so that it is analyzed with tight-binding method for high accuracy, emerged as a useful method for studying structural and dynamical properties of covalent systems. The tight biding potential used for silicon crystalline is the one of GSP known as a transferable potential. Due to the nature of rare events, the analysis is executed by action-derived molecular dynamics (ADMD) calculations. The changes of the system energy due to dislocation glide are explored with a More >

Chun-Lang Yeh¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.2, pp. 81-94, 2009, DOI:10.3970/icces.2009.009.081

Abstract In this study, the vaporization process of a nanojet is investigated by molecular dynamics simulation. Liquid argon nanojet made of 44000 Lennard-Jones molecules is investigated under various simulation parameters to examine their influence on the nanojet vaporization process. Snapshots of the molecules, evolution of the density field, and evolution of the intermolecular force are analyzed. The present simulation results can provide insight into the fundamental mechanism of the atomization process and will be helpful for the design of nanojet devices such as nano-printer or nano-sprayer. More >

Chun-Lang Yeh ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.3, pp. 253-284, 2009, DOI:10.3970/cmes.2009.050.253

Abstract This paper investigates the instability of a liquid thread by molecular dynamics (MD) simulation. The influences of liquid thread radius, fundamental cell length, and temperature are discussed. Snapshots of molecules, number of liquid particles formed, and density field are analyzed. Two linear stability criteria, namely Rayleigh's stability criterion and Kim's stability criterion, are accessed for their validity in molecular scale. It is found that a liquid thread is more unstable and produces more liquid particles in the fundamental cell when it is thinner or at a higher temperature. In addition, a liquid thread with a More >

Tai-Ming Chang¹, Chien-Chou Weng¹, Mei-Jiau Huang^1,2, Chun-KaiLiu², Chih-Kuang Yu²

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.1, pp. 47-66, 2009, DOI:10.3970/cmes.2009.050.047

Abstract We employ the non-equilibrium molecular dynamics (NEMD) simulation to calculate the in-plane thermal conductivity of silicon thin films of thickness 2.2nm and 11nm. To eliminate the finite-size effect, samples of various lengths are simulated and an extrapolation technique is applied. To perform the quantum correction which is necessary as the MD simulation temperature is lower than Debye temperature, the confined phonon spectra are obtained in advance via the EMD simulations. The investigation shows the thermal conductivities corrected based on the bulk and thin-film phonon densities of states are very close and they agree excellently with More >

Itsuo Hanasaki, Hirofumi Shintaku, Satoshi Matsunami, Satoyuki Kawano¹

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.2, pp. 191-208, 2009, DOI:10.3970/cmes.2009.046.191

Abstract Self-assembly is one of the physical phenomena that are promising for the manufacturing process of the devices on which DNA molecules are mounted as the components. We have conducted a structural study of self-assembled poly(dA)\discretionary poly(dT) DNA networks on mica surface to discuss the design requirements. The results indicate that the network formation process consists of the adsorption and the subsequent coarsening. The final form of the component filaments are roughly straight. These characteristics imply the possible tensile loads during the network formation. Therefore, we have conducted molecular dynamics simulations of tensile tests of a More >

Chun-Lang Yeh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.2, pp. 179-200, 2009, DOI:10.3970/cmes.2009.039.179

Abstract In this research, the atomization process of a nanojet is investigated by molecular dynamics simulation. Liquid argon nanojet made of 44000 Lennard-Jones molecules is examined under various simulation parameters to study their influence on the nanojet atomization process. Snapshots of the molecules, evolution of the density field, and evolution of the intermolecular force are analyzed. The present simulation results can provide insight into the fundamental mechanism of the atomization process and will be helpful for the design of nanojet devices such as nano-printer or nano-sprayer. More >

D. S. Liu¹, C.Y. Tsai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.1, pp. 29-48, 2009, DOI:10.3970/cmes.2009.039.029

Abstract Utilizing a thin copper substrate for illustration purposes, this study presents a novel numerical method for extracting the thermo-mechanical properties of a thin-film. In the proposed approach, molecular dynamics (MD) simulations are performed to establish the load-displacement response of a thin copper substrate nanoindented at temperatures ranging from 300~1400 K. The load data are then input to an artificial neural network (ANN), trained using a finite element model (FEM), in order to extract the material constants of the copper substrate. The material constants are then used to construct the corresponding stress-strain curve, from which the… More >

Shu-Feng Lee¹, Che-Wun Hong^1,2

CMC-Computers, Materials & Continua, Vol.12, No.3, pp. 223-236, 2009, DOI:10.3970/cmc.2009.012.223

Abstract Solid oxides, such as ceria (CeO₂) doped with cations of lower valance, are potential electrolytes for future solid oxide fuel cells. This is due to the theoretically high ionic conductivity at low operation temperature. This paper investigates the feasibility of two potential electrolytes which are samarium-doped ceria (SDC) and gadolinium-doped ceria (GDC) to replace the traditional yttria-stablized zirconia (YSZ). Molecular simulation techniques were employed to study the influence of different dopant concentrations at different operation temperatures on the ionic conductivity from the atomistic perspective. Simulation results show that the optimized ionic conductivity occurs at 11.11mol% concentration More >