• Journal of the Optical Society of Korea
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• v.10 no.2
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• pp.57-62
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• 2006

Adaptive optics (AO) has been applied in various fields including astronomy, ophthalmology and high power laser systems. An adaptive optics system for a high power laser is not significantly different from other AO systems in the point of configuration except that high energy absorbed by the deformable mirror distorts the deformable mirror surface and so degrades system performance. Currently we are researching a bimorph deformable mirror for beam cleaning of a high power class laser. The bimorph mirror was considered to have 99% reflective coating and 1% absorption. So this paper first presents the temperature profiles and corresponding thermal distortions of the bimorph mirror faceplate when the mirror is under a high power lasing for 10 seconds. The analysis was accomplished by the use of finite difference and finite element computer programs to generate the element arrays, calculate the temperature profiles, and determine the structural deformations. Then this paper proposes an 'embedded wafer' type water-cooling system with derived cooling parameters.

• Interaction and multiscale mechanics
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• v.5 no.3
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• pp.287-318
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• 2012

We apply a partitioned-solution (iterative-staggered) coupling method based on a fixed Eulerian mesh with the level set function to a large-deformation fluid-structure interaction (FSI) problem where a large-deformable thin structure moves in a high-speed flow field, as an airbag does during deployment. This method combines advanced fluid and structure solvers-specifically, the constrained interpolation profile finite element method (CIP-FEM) for fluid Eulerian mesh and large-deformable structural elements for Lagrangian structural mesh. We express the large-deformable interface as a zero isosurface by the level set function, and introduce virtual nodes with level sets and structural normal velocities to generate the level set function according to the large-deformable interfacial geometry and enforce the kinematic condition at the interface. The virtual nodes are located in the direction normal to the structural mesh. It is confirmed that application of the method to unfolded airbag deployment simulation shows the adequacy of the method.

• Journal of Adhesion and Interface
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• v.24 no.2
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• pp.41-53
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• 2023

The deformable devices refer to the devices that can maintain their initial performance even when stretched or bent. Among the materials used as conductor in deformable devices, Ga-based liquid metal is one of the most promising materials because it can provide not only high conductivity and deformability but also low toxicity. In this paper, we introduce Ga-based liquid metals and then discuss the recent research trend in deformable devices composed of Ga-based liquid metal.

• Journal of the Korean Society for Heat Treatment
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• v.27 no.5
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• pp.235-241
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• 2014

Effects of rolling and cooling conditions on microstructures and mechanical properties of high-deformable pipeline steels were investigated in this study. Six kinds of pipeline steels were fabricated by varying rolling and cooling conditions, and their microstructures were analyzed by scanning electron microscopy, electron back-scattered diffraction, and transmission electron microscopy. Tensile and Charpy impact tests were conducted on the steels in order to examine the mechanical properties. The steels rolled in the two-phase region showed better low-temperature toughness than those in the single-phase region due to the larger amount of ferrites having high-angle boundaries, although they have lower strength and absorbed energy. The steel rolled in single-phase and finish-cooled at higher temperature showed a good combination of high strength and good low-temperature toughness as well as excellent deformability of the lowest yield ratio and the highest uniform elongation because of the presence of fine ferrite and a mixture of various low-temperature transformation phases.

• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.483-489
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• 2004

Fexofenadine HCl is non-sedating histamine H1 receptor antagonist that can be used for the treatment of seasonal allergic rhinitis. The objective of this study was to investigate whether the carriers of deformable liposomes can enhance the transepithelial permeability of fexofenadine HCl across the in vitro ALI human nasal monolayer model. Characterization of this model was achieved by bioelectric measurements and morphological studies. The passage 2 and 3 of cell monolayers exhibited the TEER value of $2852\;{\pm}\;482\;ohm\;{\times}\;cm^2$ on 11 days of seeding and maintained high TEER value for 5 days. The deformable liposome of fexofenadine HCl was prepared with phosphatidylcholine (PC) and cholic acid using extruder method. The mean particle size was about 200 nm and the maximum entrapment efficiency of 33.0% was obtained in the formulation of 1% PC and $100\;{\mu}g/ml$ fexofenadine HCl. The toxicity of the deformable liposome to human nasal monolayers was evaluated by MTT assay and TEER value change. MTT assay showed that it has no toxic effect on the nasal epithelial cells in 2-hour incubation when the PC concentration was below 1%. However, deformable liposome could not enhance the transepithelial permeability $(P_{app})$ and cellular uptake of fexofenadine HCl. In conclusion, the in vitro model could be used in nasal drug transport studies and evaluation of transepithelial permeability of formulations.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.221-224
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• 1996

Since impact phenomenon is highly nonlinear, the analysis and control of the contact motion has been a challenging subject. Various researches have been carried out mostly for the contact of a rigid robotic manipulator with a stiff and elastic environment. This paper is motivated by a new contact task: the in-circuit test of a printed circuit board. In this process, high speed contact occurs between a rigid probing manipulator and a plastically deformable work environment. A new dynamic model of the impact controlled probing task has been proposed, considering contact with the plastically deformable object. Approaching velocity conditions to avoid an excess of the allowable penetration depth and control the generated impact force properly are derived from the proposed model. The results of the simulation studies are made for various probing conditions and show the validity of the proposed model.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.557-562
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• 2004

For constructing virtual environment it is more natural to model object as deformable body than as rigid body. High accuracy of simulation of model and low-latency computational cost for real-time simulation should be guaranteed. We pre-compute Green function through finite element analysis of deformable body and it is possible to simulate deformation of body in real-time environment using Capacitance Matrix Algorithm. Also, the capacitance matrix algorithm enables to construct the haptic rendering which serves the reaction force through a haptic device. The Newmark scheme is used for the more realistic haptic rendering and dynamic simulation in real-time.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.4
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• pp.159-168
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• 2018

In recent, mobile augmented reality game which has been attracting high attention is considered to be an good approach to increase immersion. In conventional augmented reality-based games that recognize target objects using a mobile camera and show the matching game characters, touch-based interaction is mainly used. In this paper, we propose an intuitive interaction method which manipulates a deformable game object by moving a target image of augmented reality in order to enhacne the immersion of the game. In the proposed method, the deformable object is intuitively manipulated by calculating the distance and direction between the target images and by adjusting the external force applied to the deformable object using them. In this paper, we focus on the cloth deformable object which is widely used for natural object animation in game contents and implement natural cloth simulation interacting with game objects represented by wind and rigid objects. In the experiments, we compare the previous commercial cloth model with the proposed method and show the proposed method can represent cloth animation more realistically.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.1
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• pp.47-52
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• 2013

In order to operate a search and rescue robot in hazardous area, the robot requires high mobility and adaptable locomotion for moving in unpredictable environments. In this paper, we propose the deformable soft wheel robot that can produce three kinds of driving modes; caterpillar driving mode, normal wheel driving mode, legged-wheel driving mode. The robot changes its driving mode as it faces the various obstacles such as a small gap, stairs etc. Soft film and composite materials are used for fabrication of deformable wheel structure and Shape Memory Alloy (SMA) coil spring actuators are attached on the structure as an artificial muscle. Film lamination and an composite manufacturing process is introduced and the robot design is required to be modified and compromised to applying the manufacturing process. The prototype is developed and tested for verifying feasibility of the deformable wheel locomotion.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.3
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• pp.149-154
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• 2002

In this paper, we propose a new graphic deformation algorithm for haptic interface system. Our deformable model is based on non-linear elasticity, anisotropy behavior and the finite element method. Also we developed controller for high-speed communication. The proposed controller is based on the PCI/FPGA technology, which could progress the capability of the position calculating and the force data transmitting. The haptic system is composed of the 6DOF force display device, the high-speed controller, HIR library for 3D graphic deformation algorithm and the haptic rendering algorithm. The developed system will be used on constructing the dynamical virtual environment. We demonstrate the relevance of this approach for the real-time simulating deformations of elastic objects. To show the efficiency of our system, we programmed the simulation of force reflecting. As the result of experiment, we found that it has high stability and easy to control for deformable object than some other systems.