• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.75-80
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• 2005

Study for toner adhesion is known as an important role in electrophotography. In this research, a centrifugal detachment method was used to measure the adhesion force of several hundred particles simultaneously and to determine its sensitivity to particle size. For uncharged toner particles, we estimated the van der Waals force based on the centrifugal farce experiments. Then for charged toner particles, the centrifugal force experiments were carried out. The difference between the results for charged toner particles and the results for uncharged toner particles was compared with the image force calculated from a model which assumed that the toner charge was located at the center of the particle. In the calculations, experimental data obtained by E-SPART (Electrical- Single Particle Aerodynamic Relaxation Time) analyzer were used. The adhesion force of micro-sized toner particles deposited on the DR surface was found to be approximately 1${\~}$3 nN.

• Tribology and Lubricants
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• v.19 no.4
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• pp.230-236
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• 2003

In applications such as MEMS and NEMS devices, the adhesion force and contact load may be of the same order of magnitude and the static friction coefficient can be very large. Such large coefficient may result in unacceptable and possibly catastrophic adhesion, stiction, friction and wear. To obtain the static friction coefficient of contacting real surfaces without the assumption of an empirical coefficient value, numerical simulations of the contact load, tangential force, and adhesion force are preformed. The surfaces in dry contact are statistically modeled by a collection of spherical asperities with Gaussian height distribution. The asperity micro-contact model utilized in calculation (the ZMC model), considers the transition from elastic deformation to fully plastic flow of the contacting asperity. The force approach of the modified DMT model using the Lennard-Jones attractive potential is applied to characterize the intermolecular forces. The effect of the surface topography on the static friction coefficient is investigated for cases rough, intermediate, smooth, and very smooth, respectively. Results of the static friction coefficient versus the external force are presented for a wide range of plasticity index and surface energy, respectively. Compared with those obtained by the GW and CEB models, the ZMC model is more complete in calculating the static friction coefficient of rough surfaces.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1005-1011
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• 2007

The brake system of train must posses the large braking effort in order to stop the train safely within the limited traveling distance. But, the excessive braking effort has been deteriorated the ride comfort due to high level of deceleration and jerk, and sometimes occurred the skid, because the applied braking force exceeds the allowable adhesive force. This skid causes not only to increase the stopping distance but also to deteriorate the safety of train and damage the rail surface by wheel flat. In the present paper, the braking force for disc brake of Korea High Speed Train (HSR350x) was measured through on-line test and the adhesion force was estimated by using the analytic model in the skid condition. Also, we have discussed the relationship between the actual disc brake force and the adhesion force in real skid condition.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.2-5
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• 2011

This paper presents a numerical study on multiphase flows induced by wall adhesion The CSF(Continuum Surface Force} model is used for the calculation of the surface tension force and implemented in an in-house solution code(PowerCFD). The present method(code) employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with volume capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing As an application of the present method, the effects of wall adhesion are numerically simulated with the CSF model for a shallow pool of water located at the bottom of a cylindrical tank. Two different cases are computed, one in which the water wets the wall and one in which the water does not wet the wall. It is found that the present method simulates efficiently and accurately surface tension-dominant multiphase flows induced by wall adhesion.

• Journal of the Semiconductor & Display Technology
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• v.9 no.4
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• pp.87-91
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• 2010

Charged micro-particles are widely used as the key components for many electrical applications such as an e-paper, a touch panel, a printer toner and an electronic ink. Among them, the e-paper is an emerging reflective type display using the charged particles that has the advantages of the extremely low power consumption and sunlight readability. To create images on the e-paper, we confine black positively-charged and white negatively-charged particles between bottom and top electrodes and selectively apply the electric field. When the Coulomb force by an applied electric field is greater than the adhesion force between the charged particle and the electrode, the particles' transition happens resulting in the change of color between black and white. Therefore, the adhesion force is a very important factor for designing and estimating e-paper's operation. In this study, we constructed a basic model for particle's transition and an adhesion force equation describing particle's transition with three different forces: electrostatic image force, Van der Waals force and gravitational force. The simulation results showed that the gravitational force is negligible for the interesting range for the charge and the radius, and the adhesion force can be strongly dependent on the particle's charge and radius.

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.12-18
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• 2024

A Electrostatic chuck is a device that fixes the substrate, using the force between charges applied between two parallel plates to attract substrates such as wafers or OLED panels. Unlike mechanical suction methods, which rely on physical fixation, this method utilizes the force of electrostatics for fixation, making it important to verify the adhesion force. As the size of the substrate increases, deformations due to gravity or chucking force also increase, and the adhesion force decreases rapidly as the distance between the chuck and the substrate increases. The outlook for displays is shifting from small to large OLEDs, necessitating consideration of substrate deformations. In this paper, to confirm the deformation of the substrate through various patterns, a simplified 2D model using Ansys' electromagnetic field analysis program, Maxwell, and the static structural analysis program, Mechanical, was utilized to observe changes in adhesion force according to the variation in the air gap between the substrate and the chuck. Additionally, the chucking force was analyzed for the size of the substrate, and the deformation of the substrate was confirmed when gravity and chucking force act simultaneously.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.721-730
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• 2012

The present paper presents a numerical study on multiphase flows induced by wall adhesion. The continuum surface force (CSF) model with the wall adhesion boundary condition model is used for calculating the surface tension force; this model is implemented in an in-house solution code (PowerCFD). The present method (code) employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with a volume capturing method (CICSAM) in a volume of fluid (VOF) scheme for phase interface capturing. The effects of wall adhesion are then numerically simulated by using the present method for a shallow pool of water located at the bottom of a cylindrical tank with no external forces such as gravity. Two different cases are computed, one in which the water wets the wall and one in which the water does not wet the wall. It is found that the present method efficiently simulates the surface tension-dominant multiphase flows induced by wall adhesion.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.97-106
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• 2011

Purpose: This review article was written to theoretically compare the depressing force (pressure, adhesion) to the cornea between when the spherical lenses were being tightly and flat fitted. Methods: Mathematical equations and their numerical solution programs (model) were formulated to calculate the depressing (adhesion) force to the cornea by both the tightly and flat fitted contact lenses. Based on this proposed model the effects of parameters characterizing a contact lens such as BCs, diameters, edge shape and corneal shape (ratio of long and short corneal axis, p) on the depressing force to the cornea were predicted/analyzed in both tightly and flat fitting regimes. Results: Corneal adhesion increased as the corneal p-value increased. Adhesion increase caused by the increased p-value was much larger in flat fitted case than in tight fitted one. Corneal adhesion reduced abruptly as the BC increased in flat fitting regimes while the adhesion rise was insignificant in tight fitting ones. Reduction in corneal adhesion due to lens-size increase was predicted to be insignificant in both tight and flat fitting regimes. Both the lens edge shape (edge angle) and thickness were relevant only in tight fitting regime. Corneal adhesion increased as the increased with tight-fitted lenses. As the thickness of tight fitted lenses increased, corneal adhesion inversely decreased. Conclusions: The two most significantly affecting the depressing force to cornea were found to be the degree of corneal bending toward the periphery and the BCs of lenses.

• Journal of Practical Engineering Education
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• v.15 no.2
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• pp.419-427
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• 2023

In this study, optimal adhesion conditions to alleviate defects caused by heat shrinkage with FDM type 3D printers with machine learning are researched. Machine learning is one of the "statistical methods of extracting the law from data" and can be classified as supervised learning, unsupervised learning and reinforcement learning. Among them, a function model for adhesion between the bed and the output is presented using supervised learning specialized for optimization, which can be expected to reduce output defects with FDM type 3D printers by deriving conditions for optimum adhesion between the bed and the output. Machine learning codes prepared using Python generate a function model that predicts the effect of operating variables on adhesion using data obtained through adhesion testing. The adhesion prediction data and verification data have been shown to be very consistent, and the potential of this method is explained by conclusions.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1765_1766
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• 2009

In this paper, we propose the mathematical model for the vehicle system and the observer for adhesion force. To model the dynamic properties of vehicle system, we have considered two fundamental parts. The first part is the motion equations for vehicle based on Newton's second law. The second part is the torque dynamics of the traction motor. These parts are affected by outer conditions such as adhesive coefficient, running resistance and gradient resistance. The each parts are presented by the numerical formula. From two equations, we get the observer on adhesion force. Simulation results show that the proposed observer have the good performance compared with the normal observer.