• Journal of the Korea Computer Graphics Society
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• v.25 no.1
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• pp.1-11
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• 2019

More force must be applied when dragging a wet compared with a dry cloth lying on the table. Increased force is needed because the fluid between the cloth and the surface of the table produces an adhesion force. In this paper, we study the adhesion force between a wet cloth and the surface of an object. To compute the adhesion force, we used the adhesion force model used in textile research based on real-world experiments and also considered the effect of wrinkles, which, to our knowledge, has not been investigated in previous work. Furthermore, we studied the phenomenon in which a wet cloth adheres to the surface of an object and that in which a wet cloth adheres to itself when undergoing self-collision.

• Tribology and Lubricants
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• v.17 no.3
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• pp.191-197
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• 2001

Nano adhesion and friction characteristics between SPM(scanning electron microscope) tips and flat plates of different materials were experimentally studied. Tests were performed to measure adhesion and friction in AFM(atomic force microscope) and LFM(lateral force microscope) modes in different conditions of relative humidity. Three different Si$_3$N$_4$ tips (rdaii : 15nm, 22nm and 50 nm) and three different flat plates of Si-wafer(100), W-DLC(tungsten-incorporated diamond-like carbon) and DLC were used. Results generally showed that adhesion and friction increased with the tip radius, and W-DLC and DLC surfaces were superior to Si-wafer. But the adhesion force of Si-wafer showed non linearity with the tip radius while W-DLC and DLC surfaces showed good correlation to the “JKR model”. It was found that high adhesion force between Si-wafer and a large radius of tip was caused by a capillary action due to the condensed water.

• Tribology and Lubricants
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• v.17 no.4
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• pp.276-282
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• 2001

Nano adhesion between SPM (scanning probe microscope) tips and 075 (octadecyltrichlorosilane) SAM (self-assembled monolayer) was experimentally studied. Tests were performed to measure the nano adhesion and friction in both AFM(atomic force microscope) and LFM(lateral force microscope) modes in various conditions of relative humidity. OTS SAM was formed on Si-wafer (100) surfaces, and Si$_3$N$_4$ tips of different radius of curvature were used. When the surface was hydrophobic, the adhesion and friction forces were found lower than those of bare Si-wafer. Results also showed that micro-adhesion force increased as the relative humidity and the tip radius of curvature increased. The main parameter for affecting the micro-adhesion was found absorbed humidity on the contact surface. These results were discussed with the JKR model and a capillary force caused by absorbed water.

• Tribology and Lubricants
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• v.39 no.1
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• pp.8-12
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• 2023

This study presents a molecular simulation of adhesion control between carbon nanotube (CNT) and Ag thin film deposited on silicon substrate. Rough and flat Ag thin film models were prepared to investigate the effect of surface roughness on adhesion force. Heat treatment was applied to the models to modify the adhesion characteristics of the Ag/CNT interface based on thermal wetting. Simulation results showed that the heat treatment altered the Ag thin film morphology by thermal wetting, causing an increase in contact area of Ag/CNT interface and the adhesion force for both the flat and rough models changed. Despite the increase in contact area, the adhesion force of flat Ag/CNT interface decreased after the heat treatment because of plastic deformation of the Ag thin film. The result suggests that internal stress of the CNT induced by the substrate deformation contributes in reduction of adhesion. Contrarily, heat treatment to the rough model increases adhesion force because of the expanded contact area. The contact area is speculated to be more influential to the adhesion force rather than the internal stress of the CNT on the rough Ag thin film, because the CNT on the rough model contains internal stress regardless of the heat treatment. Therefore, as demonstrated by simulation results, the heat treatment can prevent delamination or wear of CNT coating on a rough metallic substrate by thermal wetting phenomena.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.620-622
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• 2004

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and the floor decreases suddenly, the robot has a slip state. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. First of all, this paper shows that conventional PI control can not be applied to a wheeled robot of the light weigh. Secondly, reposed fuzzy logic applied by the Takagi-Sugeno model for the configuration of fuzzy sets. For the design of Takaki-Sugeno model and fuzzy rule, proposed algorithm uses FCM(Fuzzy c-mean clustering method) algorithm. In additionally, this algorithm controls recovered driving torque for the restrain the re-slip. The proposed fuzzy logic controller(FLC) is pretty useful with prevention of the slip phenomena through that compare fuzzy with PI control for the controller performance in the re-adhesion control strategy. These procedures are implemented using a Pioneer 2-DXE wheeled robot parameter.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.1
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• pp.48-55
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• 2005

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and floor decreases suddenly, the robot begins slip. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. First of all, this paper shows that conventional PI control can not be applied to a wheeled robot of the light weight. Secondly, proposed fuzzy logic is applied to the Takagi-Sugeno model for the configuration of fuzzy sets. For the design of Takagi-Sugeno model and fuzzy rule, proposed algorithm uses FCM(Fuzzy c-mean clustering method) algorithm. In additionally, this algorithm adjusts the driving torque for restraining re-slip. The proposed fuzzy logic controller(FLC) is pretty useful with prevention of the slip phenomena for the controller performance in the re-adhesion control strategy, These procedures are implemented using a Pioneer 2-DXE wheeled robot parameter.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.30-32
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• 2005

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and floor decreases suddenly, the robot begins slip. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. First of all, this paper shows that conventional PI control can not be applied to a wheeled robot of the light weight. Secondly, proposed fuzzy logic is applied to the Takagi-Sugeno model for the configuration of fuzzy sets. For the design of Takagi-Sugeno model and fuzzy rule, proposed algorithm uses FCM(Fuzzy c-mean clustering method) algorithm. The proposed fuzzy logic controller(FLC) is pretty useful with prevention of the slip phenomena for the controller performance in the re-adhesion control strategy.

• Smart Media Journal
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• v.5 no.1
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• pp.137-142
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• 2016

In this paper, a multi-scale model is applied to the simulation of thrombus growth. This model includes macroscale model and microscale model. The former is used to model the plasma flow with Navier-Stokes equations, and the latter is used to model the platelets adhesion and aggregation, thrombus motion, and the surface expansion of thrombus. The force acting on platelets and thrombus from plasma is modeled by the drag force, and the forces from biochemical reactions are modeled by the adhesion force and the aggregation force. As more platelets are merged into the thrombus, the thrombus surface expands. We proposed a thrombus growth model for simulating the expansion of thrombus surface and tracking the surface by Level Set Methods. We implemented the computational model. The model performs well, and the experimental results show that the shape of thrombus in level set expansion form is similar with the thrombus in clinical test.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.105-110
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• 2006

Study for toner adhesion is 3non 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 force 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 $1{\sim}3$ nN.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.449-449
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• 2011

We reported the direct effect of intrinsic surface energy of dry adhesive material to the Van der Waals and capillary forces contributions of the total adhesion force in an artificial gecko-inspired adhesion system. To mimic the gecko foot we fabricated tilted nanohairy structures using both lithography and ion beam treatment. The nanohairy structures were replicated from Si wafer mold using UV curable polymeric materials. The control of nanohairs slanting angles was based on the uniform linear argon ion irradiation to the nanohairy polymeric surface. The surface energy was studied utilizing subsequent conventional oxygen ion treatment on the nanohairy structures which resulted in gradient surface energy. Our shear adhesion test results were found in good agreement with the accepted Van der Waals and capillary forces theory in the gecko adhesion system. Surface energy would give a direct impact to the effective Hamaker constant in Van der Waals force and the filling angle (${\varphi}$) of water meniscus in capillary force contributions of gecko inspired adhesion system. With the increasing surface energy, the effective Hamaker constant also increased but the filling angle decreased, resulting in a competition between the two forces. Using a simple mathematical model, we compared our experimental results to show the quantitative contributions of Van der Waals and capillary forces in a single adhesion system on both hydrophobic and hydrophilic surfaces. We found that the Van der Waals force contributes about 82.75% and 89.97% to the total adhesion force on hydrophilic and hydrophobic test surfaces, respectively, while the remaining contribution was occupied by capillary force. We also showed that it is possible to design ultrahigh dry adhesive with adhesion strength of more than 10 times higher than apparent gecko adhesion force by controlling the surface energy and the slanting angle induced-contact line of dry adhesive the materials.