• Tribology and Lubricants
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• v.39 no.5
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• pp.216-219
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• 2023

This study employs molecular dynamics simulations to investigate the material behavior of workpieces in waterjet machining processes. To gain fundamental insights into waterjet machining, simulations were conducted using pure water, excluding abrasive particles. The simulation model comprised thousands of water molecules interacting with a single crystal metal workpiece. Water molecule clusters were imparted with various velocities to initiate collisions with the metal workpiece. The material behavior of the metal surface was analyzed with respect to the applied velocity conditions, considering the intricate interplay between water molecules and the workpiece at the atomic scale. The results demonstrated that the machining of the metal workpiece occurred only when water molecules were endowed with velocities above a certain threshold. In cases where energy was insufficient, the metal workpiece exhibited a slight increase in surface roughness due to mild plastic deformation, without undergoing substantial material removal. When machining occurred, the ejection of material revealed a 3-fold symmetric pattern, confirming that material removal in waterjet machining of the metal workpiece is primarily driven by plastic deformation-induced material ejection. This research provides crucial insights into the mechanisms underlying waterjet machining and enhances our understanding of material behavior during the process. The findings can be valuable in optimizing waterjet machining techniques.

• Membrane Journal
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• v.27 no.2
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• pp.121-128
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• 2017

Mesoscale simulation is a type of molecular simulation techniques where groups of atoms are defined as a single bead for calculations, and accordingly, is possible to simulate longer time ($ns{\sim}{\mu}s$) and bigger size ($nm{\sim}{\mu}m$). There are two types of mesoscale simulations : (1) particle-based mesoscale which simulates the system by calculating the movement of the particles themselves and (2) field theory which simulates the system by calculating changes in the chemical potential filed or density field. Mesoscale simulations are powerful tools to study the macroscopic properties of polymers for various applications of energy and environment. In this review, we report the trends and useful information in mesoscale simulation and provide an opportunity for membrane researchers working in the energy-environment field to understand mesoscale simulation techniques.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.71.2-71.2
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• 2010

We present the results of FUV dust scattering simulation, which is based on the Monte-Carlo method. In this simulation, we focus on the multiple scattering in the Ophiuchus complex region because the single scattering case in the region already reported by Lee et al. 2008. We compare the simulation result to the FUV intensity with FIMS and the single scattering result. We also discuss the parameters related to the results of this simulation, such as asymmetry factor, albedo and other different setting-ups.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.236.1-236.1
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• 2005

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.237.2-237.2
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• 2005

• Proceedings of the Korean Society of Rheology Conference
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• 2001.09a
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• pp.156.1-156
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• 2001

(No abstract, see full-text)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.597-598
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• 2011

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3039-3042
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• 2012

Pressure tensors at the planar surface of liquid-vapor argon are evaluated from the virial theorem, Irving-Kirkwood, and Harasima versions using a test-area molecular dynamics simulation method through a Lennard-Jones intermolecular potential at two temperatures. We found that the normal and transverse components of the pressure tensor, $p_N(z)$ and $p_T(z)$, obtained from the virial theorem and Harasima version are essentially the same. The normal component of the pressure tensor from Irving-Kirkwood version, $p_N^{IK}(z)$, is shown to be a nearly constant at the lower temperature, independent of z, as agreed in a previous study, but not for $p_N^H$(z), while the transverse components, $p_T^{IK}(z)$ and $p_T^H(z)$, are almost the same. The values of surface tension for both versions computed from $p_N(z)-p_T(z)$ are also the same and are fully consistent with the experimental data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1394-1405
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• 2002

The performance of micro-actuators utilizing radiometric forces are studied numerically. The Knudsen number based on gas density and characteristic dimension is varied from near-continuum to highly rarefied conditions. Direct simulation Monte Carlo(DSMC) calculations have been performed to estimate the performance of the micro-actuators. In the present DSMC method, the variable hard sphere molecular model and no time counter technique are used to simulate the molecular collision kinetics. For simulation of diatomic gas flows, the Borgnakke-Larsen phenomenological model is adopted to redistribute the translational and internal energies.

• CELLMED
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• v.3 no.2
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• pp.12.1-12.4
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• 2013

Identification of target protein is an important procedure in the course of drug discovery. Because of complexity, action mechanisms of herbal medicine are rather obscure, unlike small-molecular drugs. Inverse docking simulation is a reverse use of molecular docking involving multiple target searches for known chemical structure. This methodology can be applied in the field of target fishing and toxicity prediction for herbal compounds as well as known drug molecules. The aim of this review is to introduce a series of in silico works for predicting potential drug targets and side-effects based on inverse docking simulations.