• Archives of Reconstructive Microsurgery
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• v.4 no.1
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• pp.16-22
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• 1995

We analyzed 11 children who underwent epiphyseal transplantation to the forearm for manage growing deformity ranged from 2 years 6 months to years(average 5 years 10 months) follow-up period. Etiologies of the functional impairment of the eleven were five traumatic, three congenital and three tumorous conditions. Lesions of epiphysis were distal radius in eight patients and distal ulna in three patients. Operation was performed with removal of non-functioning or deformed epiphysis followed by transplantation of free vascularized proximal fibular epiphysis with microvascular anastomesis. Evaluation was performed radiologically and functionally. The 9(81.8%) patients showed growth of transplanted epiphysis by radiological examination during follow up. At the last follow up, average growth rate was 0.86cm per year excepts 2 cases of no growth. Active wrist motion near normal to contralateral joint was achieved in 7 patients. In other 2 patients, active joint motion was improved but weaker than contralateral joint. Complications on donor site were two transient peroneal nerve palsy which have been resolved after 2 and 5 months post operation and one valgus ankle deformity. The ankle deformity was corrected with $Langenski\"{o}ld$ operation of the dital tibiofibular fusion. At recipient site, there was one superficial infection and it was easily controlled by systemic antibiotics. Many subsequent reports have described successful nonvascularized epiphyseal transplante, but overall results have been inconsistent and unsatisfactory. Other experimental and clinical studies in the transfer of vascularized epiphyses has encourage its clinical application. We also could gel successful growth in several cases with free vascularized epiphyseal transplantation.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.2
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• pp.48-59
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• 1992

In this paper, the effects of a skirt deformation on the responses of an Air Cushion Vehicle in waves are investigated. The air in the bag and in the plenum chamber is assumed to be compressible and to have a uniform instantaneous pressure distribution in each volume. The free surface deformation is determined in the framework of linear potential theory by replacing the cushion pressure with the pressure patch moving uniformly with an oscillating strength. And the bag-finger skirt is assumed to be deformed due to the pressure disturbance while its surface area remained constant. The restoring force and moment due to the deformation of bag-finger skirt from the equilibrium shape is included in the equations of hearse and pitch motions. The numerical results of motion responses due to various ratios of the bag and cushion pressure or bag-to-finger depth ratios are shown.

• Korea-Australia Rheology Journal
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• v.18 no.2
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• pp.109-118
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• 2006

A finite-element method was employed to analyze axisymmetric unsteady motion of a deformable bubble near the wall. In the present study a deformable bubble in a Newtonian medium near the wall was considered. In solving the governing equations a structured mesh generator was used to describe the collapse of highly deformed bubbles with the Arbitrary Lagrangian Eulerian (ALE) method being employed in order to capture the transient bubble boundary effectively. In order to check the accuracy of the present FE analysis we compared the results of our FE solutions with the result of the collapse of spherical bubbles in a large body of fluid in which solutions can be obtained using a 1D FE analysis. It has been found that 1D and 2D bubble deformations are in good agreement for spherically symmetric problems confirming the validity of the numerical code. Non-spherically symmetric problems were also solved for the collapse of bubble located near a plane solid wall. We have shown that a microjet develops at the bubble boundary away from the wall as already observed experimentally. We have discussed the effect of Reynolds number and distance of the bubble center from the wall on the transient collapse pattern of bubble.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1352-1358
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• 2004

The mechanical spring is one of widely used machine elements. Among various kinds, flat-type spring loaded by a rotating pin was studied. A flat spring was simplified to a cantilever beam, and numerical analysis was attempted. Since the loading pin rotates about a separate axis from the fixed spring or vice versa, the location, direction, and magnitude of the contact force including normal contact and friction loads vary accordingly. Meanwhile, the spring is deformed substantially as the relative motion progresses. Therefore, this problem needs to be formulated taking the follower loading characteristics and geometrical non-linearity into account. Derived nonlinear differential equation was solved to yield the spring deflection, contact force and the torque to rotate the pin, and the result was compared with a finite element solution. Also, the influences of principal design parameters were studied. The proposed methodology is expected to be useful for the design of pin-loaded flat spring and the prevention of mechanical failures in the form of yielding or fatigue failure of spring or severe wear of the components.

• Journal of ILASS-Korea
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• v.11 no.2
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• pp.89-97
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• 2006

An inviscid axisymmetric model capable of predicting droplet bouncing and the detailed pre-impact motion, influenced by the ambient pressure, has been developed using boundary element method (BEM). Because most droplet impact simulations of previous studies assumed that a droplet was already in contact with the impacting substrate at the simulation start, the previous simulations could not accurately describe the effect of the gas compressed between a failing droplet and the impacting substrate. To properly account for the surrounding gas effect, an effect is made to release a droplet from a certain height. High gas pressures are computationally observed in the region between the droplet and the impact surface at instances just prior to impact. The current simulation shows that the droplet retains its spherical shape when the surface tension energy is dominant over the dissipative energy. When increasing the Weber number, the droplet surface structure is highly deformed due to the appearance of the capillary waves and, consequently, a pyramidal surface structure is formed; this phenomenon was verified with our experiment. Parametric studies using our model include the pre-impact behavior which varies as a function of the Weber number and the surrounding gas pressure.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.77-81
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• 2002

A new method of optimal blank shape design using the initial nodal velocity (INOV) has been proposed for the drawings of arbitrary shaped cups. With the given information of tool shape and the final product shape, corresponding initial blank shape has been found from the motion of boundary nodes. Although the sensitivity method, the past work of Hynbo Shim and Kichan Son, has been proved to be excellent method to find optimal blank shapes, the method has a problem that a couple of deformation analysis is required at each design step and it also exhibits an abnormal behaviors in the rigid body rotation prevailing region. In the present method INOV, only a single deformation analysis per each design stage is required. Drawings of practical products as well as oil-pan have been chosen as the examples. At every case the optimal blank shapes have been obtained only after a few times of modification without predetermined deformation path. The deformed shape with predicted optimal blank almost coincides with the target shape at every case. Through the investigation the INOV is found to be very effective in the arbitrary shaped drawing process design.

• 한국해양학회지
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• v.28 no.1
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• pp.17-23
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• 1993

A right cylindrical tank with sloping bottom and top (${\beta}-effect$) is filled with two-layered fluid and is put on the rotating table. External fluid of same density as the lower-layer fluid is continuously injected to drive the lower-layer current. By minimizing the interfacial stress between two layers the motion in the lower-layer deformed the shape of interface such that the upper-layer adjust itself to the variations of the interface in terms of its direction of flow patterns .The most significant parameter is the internal Froude Number($F_1$) and when $F_1$ is greater than 6 two-cellular circulation of the upper-layer changes its direction, there by creates a separation of Western boundary current. The separation position moves to the most northward when $F_1$ equals to 6.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.200-205
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• 2006

Abstract This paper presents a personal identification method based on BMME and LDA for images acquired at anterior and posterior occlusion expression of teeth. The method consists of teeth region extraction, BMME, and pattern recognition forthe images acquired at the anterior and posterior occlusion state of teeth. Two occlusions can provide consistent teeth appearance in images and BMME can reduce matching error in pattern recognition. Using teeth images can be beneficial in recognition because teeth, rigid objects, cannot be deformed at the moment of image acquisition. In the experiments, the algorithm was successful in teeth recognition for personal identification for 20 people, which encouraged our method to be able to contribute to multi-modal authentication systems.

• Transactions of Materials Processing
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• v.11 no.6
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• pp.487-494
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• 2002

A new method of optimal blank shape design using the initial nodal velocity (INOV) has been proposed for the drawings of arbitrary shaped cups. With the given information of tool shape and the final product shape, corresponding initial blank shape has been found from the motion of boundary nodes. Although the sensitivity method, the past work of the present authors, has been proved to be excellent method to find optimal blank shapes, the method has a problem that a couple of deformation analysis is required at each design step and it also exhibits an abnormal behaviors in the rigid body rotation prevailing region. In the present method INOV, only a single deformation analysis per each design stage is required. Drawings of practical products as well as oil-pan, have been chosen as the examples. At every case the optimal blank shapes have been obtained only after a few times of modification without predetermined deformation path. The deformed shape with predicted optimal blank almost coincides with the target shape at every case. Through the investigation the INOV is found to be very effective in the arbitrary shaped drawing process design.

• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.3450-3462
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• 2024

This paper presents a computational framework for drop time assessment of a control element assembly (CEA) under fuel assembly (FA) deformations. The proposed framework consists of three key components: 1) finite element modeling of CEA, 2) fluid-structure interaction to compute drag force, and 3) modeling of frictional contact between CEA and FA. Specially, to accommodate the large motion of CEA, beam elements based on absolute nodal coordinate formulation (ANCF) are adopted. The continuity equation is utilized to calculate the drag force, considering flow changes in the cross-sectional area during the CEA drop. Lastly, beam-inside-beam frictional contact model is employed to capture practical contact conditions between CEA and FA. The proposed framework is validated through experiments under two scenarios: free falls of CEA within FA, encompassing undeformed and deformed scenarios. The experimental validation of the framework demonstrated that the drop time of CEA can be accurately predicted under the complex coupling effects of fluid and frictional contact. The drop times of the S-shaped deformation case is longer than those of the C-shaped deformation case, affirming the time delay due to frictional force. The validation confirms the potential applicability to access the safety and reliability of nuclear power plants under extreme conditions.