• Journal of the Korean institute of surface engineering
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• v.39 no.2
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• pp.64-69
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• 2006

Nanoscale task such as nanolithography and nanoindenting is a challenging work that is beyond the capabilities of human sensing and precision. Since surface forces and intermolecular forces dominate over gravitational and other more intuitive forces of the macro world at the nanoscale, a user is not familiar with these novel nanoforce effects. In order to overcome this scaling barrier, haptic interfaces that consist of visual and force feedback at the macro world have been used with an Atomic Force Microscope (AFM) as a manipulator at the nanoscale. In this paper, a nanoscale virtual coupling (NSVC) concept is introduced and the relationship between performance and impedance scaling factors of velocity (or position) and force are explicitly represented. Experiments have been performed for nanoindenting and nanolithography with different materials in the nanoscale virtual surface. The interaction forces (non contact and contact nanoforces) between the AFM tip and the nano sample are transmitted to the operator through the haptic interface.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.1-9
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• 2002

Where the track is continuously welded over the bridge, the longitudinal forces will be distributed interactively between the track and the sub-structure by the rail-bridge interaction mechanism. The ratio between the longitudinal forces transmitted in each elements depends on the magnitude of the ballast resistance and the stiffness of the sub-structures. In this paper, the main factors affect on the longitudinal rail force are discussed and the parametric study for the behavior of CWR(Continuous Welded Rail) track was executed. It is concluded that the horizontal ballast resistance and the stiffness of the bridge sub-structure are the significant parameters affecting the stability of the continuous welded rail track.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.144-147
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• 2001

The planar tracked vehicle model used in this investigation consists of two kinematically decoupled subsystem, i.e., the chassis subsystem and the track subsystem. The chassis subsystem include the chassis frame, sprocket, idler and rollers, while the track subsystem is represented as a closed kinematic chain consisting of rigid links interconnected by revolute joints, In this paper, the recursive kinematic and dynamic formulation of the tracked vehicle is used to find the vertical forces and the distances of the certain track moved in the driving direction along the track. These distances and vertical forces obtained are used to calculate the sinkage of a terrain. The FEM is adopted to analyze the interaction between the tracked vehicle and terrain. The terrain is represented by a system of elements with specified constitutive relationships and considered as a piecewise linear elastic, plastic and isotropic material. When the tracked vehicle is moving with different speeds on the terrain, the elastic and plastic deformations and the maximum sinkage for the four different types of a isotropic soil are simulated.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1-5
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• 2010

The Hyundai Rotem company is due to be conducted the main line Speed Qualification Test as regulated by CFR for SEPTA EMU and SCRRA Bi-level coach project. The regulated test items per 49CFR213.345 are wheel/rail interaction forces and carbody/truck accelerations during running on main line. Therefore the special two sets of instrumented wheelset (IWS) per each project have been made for measuring the interaction forces between wheel and rail at four wheels of one truck during running on main line. In this paper, regarding Speed Qualification Test, the required test items and data analysis method per 49CFR213.345 and the preparation status of instrumented wheelsets (IWS) are introduced.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.249-255
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• 2010

Ballasted track is under the circumstance of repetition of deterioration and recovery. Track deterioration is presented as track irregularity or settlement, and dynamic force subjected to track is one of major cause of the deterioration. The dynamic force is determined from the dynamic interaction between track and vehicle. Rail-pad stiffness is one of the factor affects track dynamic property. In this study, the relationship between rail-pad stiffness and track settlement was investigated. Dynamic forces according to various rail-pad stiffness was obtained from the dynamic vehicle-track interaction analysis using DARTS-NL. Track settlement was calculated by substitution the dynamic forces into various formulas for track settlement. From the result of analysis, it was known that the track settlement is increased about 6% when the rail-pad stiffness rise about twice. And this result leads that there is only a little relationship between rail-pad stiffness and track settlement.

• Macromolecular Research
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• v.14 no.6
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• pp.654-658
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• 2006

Recent developments in equations of state for molecular fluids have demonstrated the feasibility of using the hard-sphere equation to describe the effects of repulsive forces in simple fluids. By including a suitable term for attractive forces, most conveniently a uniform background potential, the properties of bio-macromolecular interaction can be roughly calculated. However, the choice of the potential used in perturbed hard-sphere chain (PHSC) theory for describing the attractions between macromolecules is rather complicated. For hard-sphere chains, the prediction accuracy from each model strongly depends on the choice of potential function.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.2
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• pp.209-218
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• 2017

Sea ice is the main factor affecting the safety of the Arctic engineering. However, traditional numerical methods derived from classical continuum mechanics have difficulties in resolving discontinuous problems like ice damage. In this paper, a non-local, meshfree numerical method called "peridynamics", which is based on integral form, was applied to simulate the interaction between level ice and a cylindrical, vertical, rigid structure at different velocities. Ice in the simulation was freshwater ice and simplified as elastic-brittle material with a linear elastic constitutive model and critical equivalent strain criterion for material failure in state-based peridynamics. The ice forces obtained from peridynamic simulation are in the same order as experimental data. Numerical visualization shows advantages of applying peridynamics on ice damage. To study the repetitive nature of ice force, damage zone lengths of crushing failure were computed and conclude that damage zone lengths are 0.15-0.2 times as ice thickness.

• Earthquakes and Structures
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• v.20 no.3
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• pp.261-278
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• 2021

In the current work, a series of seismic analyses of one-storey asymmetrical reinforced concrete (R/C) framed buildings is accomplished while the effect of soil deformability on the structural response is investigated. A comparison is performed between the simplified elastic behavior of R/C elements according to the structural regulations' instructions to the possible non-linear behavior of R/C elements under actual circumstances. The target of the time history analyses is the elucidation of the Soil-Structure Interaction (SSI) effect in the seismic behavior of common R/C structures by examining the possible elastic or elastoplastic behavior of R/C sections because of the redistribution of the internal forces by employing a realistic damage index. The conclusions acquired from the presented elastic and elastoplastic analyses supply practical guidelines towards the safer design of structures.

• Journal of the Korean Geotechnical Society
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• v.36 no.1
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• pp.5-15
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• 2020

Dynamic behavior of pile foundation is significantly influenced by the dynamic interaction between soil and pile. Especially, in the sloping ground, the soil-pile interaction becomes very complex due to different resistance according to loading direction, soil residual displacement and so on. In this study, dynamic centrifuge tests were performed on the piles in the sloping ground. The model structures consisted of a single pile and 2×2 group pile. The soil-pile interaction has been investigated considering various conditions such as slope, single and group piles, and amplitude of input motions. The phase differences between soil and pile displacement and dynamic p-y curves were evaluated. The analysis results showed that the pile behavior was largely influenced by the kinematic forces between soil and pile. In addition, the dynamic p-y curve showed the complex hysteresis loop due to the effect of slope, residual displacement, and kinematic forces.

• Journal of Photoscience
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• v.11 no.32
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• pp.65-69
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• 2004

The mechanism of interaction of four coumarin derivatives (CDS) with bovine serum albumin (BSA) was studied using spectrofluorometric technique. It was found that the coumarin ring common to all CDS makes major contribution to interaction. Binding affinities could be related to parachor values of CDS. Stem-Volmer plots indicated the presence of static component in the quenching mechanism. Results also showed that both tryptophan residues of protein are accessible to CDS. The high magnitude of rate constant of quenching indicated that the process of energy transfer occurs by intermolecular interaction forces and thus CDS binding site is in close proximity to tryptophan residues of BSA. Binding studies in the presence of the hydrophobic probe, 8-anilino-l-naphthalein-sulfonic acid showed that there is hydrophobic interaction between CDS and the probe and they do not share common sites in BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CDS to BSA involve hydrophobic bonds predominantly. The effects of various metal ions on the binding of CDS with BSA were also investigated.