• Archives of Plastic Surgery
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• v.36 no.3
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• pp.318-321
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• 2009

Purpose: The bony mallet finger injury is generally managed by conservative treatments, but operative treatments are needed especially when the fractures involve above 30% of articular surface or distal phalanx is accompanied by subluxation in the volar side. This is the reason they often result in chronic instability, articular subluxation and unsatisfactory cosmetic. In this report, We describe new method using the hook plate as an operative treatment of Mallet finger deformity. Methods: Among 13 patients with Mallet finger deformity who came from February 2006 to February 2008, six patient were included in surgical indication. Under local anesthesia, H or Y type incision was made at the DIP joint area. After the DIP joint extension, the hook plate was put on the fracture line, and one self tapping screw was used for fixation. 2 hole plate which was one of the holes in 1.5 mm diameter was cut in almost half and bended through approximately $100^{\circ}$. Results: In all six cases which applied the hook plate, complications such as loss of reduction or nail deformity were not seen. In only one patient, hook pate was removed due to inflammatory reaction after surgery. At 2 weeks after operation, active motion of DIP joint was performed. The result was satisfactory not only cosmetically but also functionally. At 6 weeks after operation, the range of motion of DIP joint was average $64^{\circ}$. Conclusion: The purpose of the operative treatment for mallet finger deformity using the hook plate is to provide anatomical reduction with rigid fixation and to prevent contracture at the DIP joint. While other operations take 6 weeks, the operation using the hook plate begins an active motion at 2 weeks after operation. Complication rate was low and the method is rather simple. Thus, the operation using the hook plate is recommended as a good alternative method of the mallet finger deformity treatment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.55-60
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• 2002

For the development of a new creep test technique, the availability of SP-Creep test is discussed for 1Cr-0.5Mo boiler header material. And some results are also compared with those of 2.25Cr- 1Mo steel which widely uses as boiler superheater tube. The results can be summarized as follows. The load exponents(n) obtained by SP-Creep test for 1Cr-0.5Mo steel are decreased with increasing creep temperature and the values are 15.67, 13.89, and 17.13 at 550$^{circ}C$ ,575$^{circ}C$ and 600$^{circ}C$, respectively. The temperature dependence of the load exponent is given by n = 107.19 - 0.1108T. This reason that load exponents show the extensive range of 10∼16 is attributed to the fine carbide such as M$_{23}$C$_{6}$ in lath tempered martensitic structures. At the same creep condition, the secondary creep rate of 1Cr-0.5Mo steel is lower than the 2.25Cr-1Mo steel1 due to the strengthening microstructure composed by normalizing and tempering treatments. Through a SEM observation, it can be summarized that the primary, secondary, and tertiary creep regions of SP-Creep specimen are corresponding to plastic bending, plastic membrane stretching, and plastic instability regions among the deformation behavior of four steps in SP test, respectively.y.

• Clinics in Shoulder and Elbow
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• v.21 no.1
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• pp.42-47
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• 2018

A 25-year-old woman presented to the emergency room with a painful and swollen right forearm. She had just sustained an injury from an accident during which her arm was tightly wound by a rope as she was lowering a net from a fishing boat. Before being released, her arm was rigidly trapped in the rope for approximately ten minutes. Radiographs revealed anterior dislocation of the radial head that was accompanied by plastic deformation of the proximal ulna, manifested as a reversal of the proximal dorsal angulation of the ulna (PUDA); suggested a Monteggia equivalent fracture. With the patient under general anesthesia, we reduced the radial head by posterior compression at $90^{\circ}$ of elbow flexion and at neutral rotation of the forearm. However, the reduction was easily lost and the elbow re-dislocated with even slight supination or extension of the arm. After the osteotomy of the ulnar deformity to restore the PUDA to normal, the reduction remained stable even with manipulation of the arm. We found that the patient could exercise a full range of motion without pain at the 3-month follow-up, and neither residual instability nor degenerative changes were observed at the final 3-year follow-up.

• Archives of Plastic Surgery
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• v.32 no.1
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• pp.5-11
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• 2005

Prostaglandin $E_1$($PGE_1$) is known to have various physiological action such as vasodilatation, decrease of blood pressure, angiogenesis, inhibition of platelet aggregation and so forth. $PGE_1$ has been developed in many different formulations in order to overcome its chemical instability and deactivation in the lungs when administered parenterally. Lipo-AS013 is a potent drug with higher chemical stability and greater vascular wall targeting than others. The study was done on $3{\times}10cm$ model flap of dorsal skin of Sprague-Dawley rats and the flap perfusion survival were observed and documented. The flap treated with Lipo-AS013 beforehand was given intravenously Sodium fluorescein 10 minutes later, and then Percent Dye Fluorescence Index(% DFI) was calculated. The results were compared to a control group and the group administered locally epinephrine.. In the control group, the % DFI and flap survival rate increased from $54.1{\pm}6.7$ to $65.0{\pm}2.6$(p<0.01) while in Lipo-AS013 group from $55.3{\pm}2.2$ to $67.4{\pm}1.9$(p<0.01), respectively. In the epinephrine group, the % DFI(p<0.05) and flap survival rate(p<0.001) decreased. In the both epinephrine and Lipo-AS013 group Percent DFI and flap survival rate are comparable with the control group.The result indicates that the potent Lipo-AS013 enhances the blood flow and flap survival. This highly potent Lipo-AS013 may have targeting ability and accumulate $PGE_1$ onto the vascular walls. A quantitative analysis of fluorescence on the skin surface is a reliable tool to measure the blood perfusion into an ischemic flap and its viability. Further comparative study with conventional $PGE_1$ and Lipo-$PGE_1$ is needed in order to clarify the action and efficiency of Lipo-AS013.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.211-218
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• 2000

Hot spot behaviors on the disk-pad contact surface during a braking operation have been analyzed for a ventilated disk brake using the finite element method. Hot spots which were studied using a coupled thermal-mechanical analysis technique are influenced by all of the mechanical, thermal, elastic and plastic processes that are involved in braking cycles, but their temperature gradients are most affected by rubbing speeds, braking forces, and design parameters between the disk and the pad. Undesirable hot spots that are generated by local thermoelastic instabilities are intended to be removed by optimized design parameters and material properties. In this study, a three-dimensional numerical method for the demonstration of hot spot behaviors has been applied to the rubbing surfaces between the disk and the pad.

• Geomechanics and Engineering
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• v.10 no.4
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• pp.437-454
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• 2016

Wellbore instability problem is one of the main problems that met frequently during drilling, particularly in high temperature, high pressure (HPHT) formations. There are large amount of researches about wellbore stability in HPHT formations, which based on the thermo-poroelastic theory and some achievements were obtained; however, few studies have investigated on the fully coupled thermo-poroelastoplasticity analysis of wellbore stability, especially the analysis of wellbore stability while the filter cake formed. Therefore, it is very necessary to do some work. In this paper, the three-dimensional wellbore stability model which overall considering the effects of fully coupled thermo-poroelastoplasticity and filter cake is established based on the finite element method and Drucker-Prager failure criterion. The distribution of pore pressure, wellbore stress and plastic deformation under the conditions of different mud pressures, times and temperatures have been discussed. The results obtained in this paper can offer a great help on understanding the distribution of pore pressure and wellbore stress of wellbore in the HPHT formation for drilling engineers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.195-199
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• 1993

In the analysis of metal forming processes by the finite element method, there are many numerical instabilities such as element locking, hourglass mode, shear locking. These instabilities may have a bad effect upon accuracy and convergence. The present work is concerned with improvement of stability and efficiency in two dimensional rigid-plastic finite element method using various type of elements and numerical integration schemes. AS metal forming examples, upsetting and backward extrusion are taken for comparison among the methods : various element types and numerical integration schemes. comparison is made in terms of stability and efficiency. As a result, it has been shown that the finite element computation is stabilized from the viewpoint of computational time, convergency, and numerical instability.

• Structural Engineering and Mechanics
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• v.2 no.2
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• pp.185-196
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• 1994

In this paper a spline function solution for the ultimate strength of steel members and member structures is derived based on total Lagrangian formulation. The displacements of members along longitudinal and transverse directions are interpolated by one-order B spline functions and three-order hybrid spline functions respectively. Equilibrium equations are established according to the principle of virtual work. All initial imperfections of members and effects of loading, unloading and reloading of material are taken into account. The influence of the instability of members on structural behavior can be included in analyses. Numerical examples show that the method of this paper can satisfactorily analyze the elasto-plastic large deflection problems of planar steel member and member structures.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.235-242
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• 2001

Inelastic seismic response of steel moment frame structures, which are usually quite gravity load and subject to large displacement under severe earthquake, may be severly influenced by the structure P-Δ effects. The P-Δ effect may have an important impact on the dynamic behavior of the structure in the nonlinear seismic analysis. In multi degree of freedom systems P-Δ effects may significantly affect only a subset of stories or a single story alone. Therefore, a story drift amplification of structure is happened by P-Δeffects and such nonlinear dynamic behaviors are very difficult to evaluate in the structures. In this study, two systems having different design methods of steel moment frame structures are investigated to evaluate the P-Δ effects due to gravity load. The plastic hinge formations, maximum rotational ductility demands, and energy distribution will be compared and evaluated following whether the P-Δ effects are considered or not. And design methods are proposed for the prevention of the instability of structures which due to the P-Δ effects.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1346-1351
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• 2003

There is few research about contact problem in SPH because it is primarily suitable to analyze the large deformation problem. However, an elasto-plastic problem with small deformation need to be considered about contact characteristics. The numerical formulating methods for SPH is induced to be able to obtain solutions based on a variational method in contact problem. The contact algorithm presented is applied to the elastic impact problem in 1D and 2D. The results show thai an imaginary tension and a numerical instability which happen in impacting between different materials can be removed and contact forces which could not have been calculated are able to obtain.