• Journal of the Korean Arthroscopy Society
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• v.16 no.2
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• pp.128-133
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• 2012

Purpose: This study examined the relationship between graft appearance on follow-up magnetic resonance imaging (MRI) and knee stability after double bundle anterior cruciate ligament (ACL) reconstruction. Materials and Methods: For each patient, 1.5 tesla MRI's were obtained. The signal intensity of grafts was divided into 3 grades by Sononda's classification. The course of grafts was divided into two patterns: straight and curved. We assessed Lachman test, KT 2000 arthrometer and anterior drawer stress radiograph using Telos$^{(R)}$ in $30^{\circ}$ knee flexion for anterior stability and evaluated pivot shift test for rotatory stability. The correlation between graft appearance on MRI and the results of knee stability tests was evaluated. Results: The anteromedial (AM) graft was evaluated as being grade 1 in 66.7%, grade 2 in 26.7%, and grade 3 in 6.7% of the cases and the posterolateal (PL) graft was assessed as being grade 1 in 63.3%, grade 2 in 33.3%, and grade 3 in 3.3% of the cases according to the signal intensity. The AM graft was evaluated as being straight in 83.3% and curved in 16.7% of the cases, and the PL graft was assessed as being straight in 86.7% and curved in 13.3% of the cases according to the course. The course of AM graft was correlated with the results of anterior stability tests and the course of PL graft was correlated with the result of rotatory stability test. However, the signal intensity of grafts was not correlated with the results of anterior stability and rotatory stability tests. Conclusion: The course of AM is correlated with anterior stability and the course of PL is correlated with rotatory stability on follow-up MRI after double bundle ACL reconstruction.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.576-581
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• 2008

High-quality double-walled carbon nanotubes (DWNTs) were synthesized without defects and amorphous carbonaceous particles by catalytic decomposition method at $800^{\circ}C$ in high yield. As-synthesized carbon materials almost consist of DWNT bundles with a diameter 12 - 20 nm.. The DWNTs rope have uniform diameter about 2 - 5 um and length up to several tens micrometer. DWNTs is inner tube diameter 0.9 - 1.5 nm and outer tube 1.6 - 2.2 nm. We investigate the crystallinity of DWNTs by TEM and Raman spectroscopy. We also found that the Fe-Mo bimetallic catalyst was active as a very efficient catalyst for the synthesis of DWNTs with the catalyst decomposition method. Our results also indicate that Tetra Hydro Furan (THF) is a very ideal carbon source for the synthesis of DWNTs.

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.1-13
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• 2021

Considerable progress on anterior cruciate ligament reconstruction surgery has been made over the past 20 years, and the results have improved significantly. An anatomical understanding of the anterior cruciate ligament has also changed, and the surgical technique has also changed accordingly. The double-bundle concept is still valid, but the ribbon-shaped anterior cruciate ligament concept, including direct fiber and indirect fiber, is gradually replacing it. The isometry point theory no longer exists, and various surgical methods, such as single-bundle anatomical reconstruction, double-bundle reconstruction, remnant preservation, and rectangular tunnel technique, are being performed. Regarding the graft, interest in the bone-patellar tendon-bone, patellar tendon, quadriceps tendon, and allogeneic tendon change over time, and this change is ongoing.

• Journal of the Korean Arthroscopy Society
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• v.16 no.1
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• pp.26-33
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• 2012

Purpose: The purpose of this study was to evaluate the clinical outcomes and stability of anatomical single bundle anterior cruciate ligament reconstruction (SBACLR) with quadriceps tendon comparable to double bundle anterior cruciate ligament reconstruction (DBACLR). Materials and Methods: We retrospectively reviewed 28 consecutive patients (16 male, 12 female) who underwent SBACLR using quadriceps tendon from March 2009 (Group 1) and compared its clinical results to whom DBACLR with semitendinosus tendon for 53 patients (51 male, 2 female) from August. 2006 (Group 2). Mean age were 34.9 (range, 16-52) in Group 1 and 21.6 (range, 17-55) in Group 2. Mean follow up periods were 13.9 months (range, 12-20) in Group 1 and 36.2 months (range, 20-52) in Group 2. Lysholm score, International Knee Documentation Committee (IKDC) evaluation form and Tegner score were performed for evaluating the clinical outcome. Lachman test, pivot shift test and KT-1000 arthrometer (MEDmetric Corp., San Diego, CA, USA) were performed for stability. Results: There was no statistical significant difference between the two groups in terms of Lysholm score (Group 1: $85.9{\pm}2.6$, Group 2: $90.9{\pm}1.0$, P=0.226), IKDC score (P=0.345) and Tegner score (Group 1: $6.9{\pm}1.4$, Group 2: $7.1{\pm}1.3$, P=0.523). Nor was there statistical significance between the two groups in terms of KT-1000 arthrometer (Group 1: $1.5{\pm}1.1\;mm$, Group 2: $1.5{\pm}1.6\;mm$, P=0.457), Lachman test (P=0.547) and pivot shift test (P=0.073). Conclusion: Anatomical SBACLR with quadriceps tendon shows similar clinical outcomes and stability comparable to anatomical DBACLR with hamstring tendon.

• 대한관절경학회:학술대회논문집
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• 2006.11a
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• pp.102-103
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• 2006

• 대한관절경학회:학술대회논문집
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• 2007.04a
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• pp.13-13
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• 2007

• 대한정형외과스포츠의학회:학술대회논문집
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• 2007.04a
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• pp.19-23
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• 2007

• Journal of the Korean Arthroscopy Society
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• v.13 no.2
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• pp.105-110
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• 2009

• Journal of the Korean Arthroscopy Society
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• v.10 no.2
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• pp.203-208
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• 2006

Purpose: Previous transtibial double bundle posterior cruciate ligament (PCL) reconstruction methods have several problems in graft length and tibial fixation. We introduce new surgical method that is less restrictive by graft length and is more stable with single tibial fixation. Operative technique: After diagnostic arthroscopy, we prepare the graft, ream the tibial tunnel and perform the procedure for TransFix tibial fixation. Femoral 2 tunnel is made and graft is passed via anteromedial (AM) portal. Tibial fixation is done and femoral 2 graft is fixed sequentially at each knee position. Conclusion: TtransFix tibial single fixation method in double bundle PCL reconstruction provides more stable fixation, more free graft selection and prevents graft damage by passing the graft via AM portal.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.1
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• pp.53-62
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• 2017

The forced convection heat transfer performance of a twist-vane spacer grid for a dual-cooled annular fuel assembly was examined experimentally. The twist-vane spacer grid was uniquely designed to enhance mixing inside subchannels and mixing between adjacent subchannels. For testing, a $4{\times}4$ square-arrayed rod bundle with narrow gaps between rods was prepared as the dual-cooled annular fuel assembly to be simulated. The pitch-to-rod diameter ratio of simulated dual-cooled annular fuel assembly was 1.08. The experiments were performed under the following conditions: axial bulk velocity, 1.5 m/s and heat flux, $26kW/m^2$. With regard to the circumferential temperature distribution, the lowest rod-wall temperatures upstream and downstream were measured at the subchannel center and the position toward the tip of twist-vane, respectively. With regard to the axial temperature distribution, behind the twist-vane spacer grid, the rod-wall temperature decreased drastically, and the Nusselt number was enhanced by up to 56 %. The present measured data indicate that the twist-vane spacer grid can effectively improve the forced convection heat transfer in the dual-cooled annular fuel assembly with narrow gaps.