• Journal of Korean Foot and Ankle Society
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• v.12 no.1
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• pp.9-13
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• 2008

Purpose: Medial capsulorrhaphy is additional hallux reduction method following various hallux reduction procedures and we are going to report author's opinion about several methods of medial capsulorrhaphy. Materials and Methods: We performed three kinds of medial capsulotomy and imbricatory capsulorrhaphy in hallux valgus surgery. Through 8 cadavar study, we compared the easiness of sesamoid reduction and hallux valgus angle reduction. Also, we measured thickness of capsule in various portions. Results: Longitudinal capsule incision and imbrication was useful in sesamoid reduction and vertical procedures was useful in hallux valgus angle reduction. The capsule thickness was measured thickest in dorsal and distal portioin. Conclusion: The methods of medial capsulorrhaphy should be planned preoperatively considering individual hallux deformities. These selected medial capsulorrhaphy can help the reduction of hallux valgus deformity correction and its maintenance.

• Journal of the Korean Magnetic Resonance Society
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• v.7 no.2
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• pp.68-73
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• 2003

Proton magic angle spinning spectra and thermogravimetric analysis data of poly(vinyl butylal) with water in it indicate water contents in the poly(vinyl butylal) samples were reduced during magic angle spinning. Our observation implies that the centrifugal force on the samples due to magic angle spinning cannot be neglected, especially on inhomogeneous and soft samples like poly(vinyl butylal) we tested in this work.

• Journal of Korean Foot and Ankle Society
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• v.21 no.1
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• pp.27-32
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• 2017

Purpose: Bone grafting is often necessary to maintain a reduction and prevent delayed collapse of reduced fracture in a treatment of severely displaced comminuted intra-articular calcaneal fractures. Herein, we analyzed the usefulness and necessary conditions to perform tricortical-allobone grafting in open reduction of calcaneal fracture via the Ollier approach. Materials and Methods: We performed a retrospective review of 57 intra-articular calcaneal fractures that underwent an operation via the Ollier approach between April 2009 and April 2015. They were divided into two groups: Group 1 (n=17) included those with tricortical-allobone grafts underneath the posterior facet fragment, and group 2 (n=40) included cases without a bone graft. We measured the $B{\ddot{o}}hler$ angle, Gissane angle, height, and width of the calcaneus at preoperative, postoperative, and final follow-up radiograph. We measured the sagittal rotational angle of the posterior facet fragment of preoperative computed tomography to analyze the effect and necessary conditions for bone grafting. We also reviewed the clinical results by the American Orthopaedic Foot and Ankle Society (AOFAS) scale, visual analogue scale (VAS), and any complications. Results: According to the Sanders classification, there were 3 type-II fractures, 12 type-III fractures, and 2 type-IV fractures in Group 1; whereas in Group 2, there were 26 type-II fractures, 13 type-III fractures, and 1 type-IV fracture (p=0.002). Regarding the preoperative radiologic parameters, there were significant differences in the $B{\ddot{o}}hler$ angle (p=0.006), Gissane angle (p=0.043), and rotational angle of the posterior facet fragment (p=0.001). No significant difference was observed in the preoperative calcaneal height and width, as well as postoperative radiologic parameters. There was no significant clinical difference between the two groups (p=0.546). Conclusion: We suggest that a tricortical-allobone graft may be useful in open reduction and screw fixation via the Ollier approach for displaced intra-articular calcaneal fracture with a bony defect after reduction of collapsed posterior facet fragment. This graft can contribute to the stable reduction via a small approach, even without a plate.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.213-216
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• 2006

This paper was a study about noise reduction through flow stabilization in duct using experimental method and numerical analysis at the same time. To determine the fan's type three kinds of fans(axial fan, centrifugal fan, and axial fan with centrifugal type blades) was examined to investigate the suitability for in-line duct. As a result, under the equal number of rotation 2000 RPM, performance of an axial fan with centrifugal type blades was the most superior by 55dBA at 4.3CMM among other fans. After this, analyzed the results of the numerical analysis to find out the optimum design of pitch angle such as $0^{\circ}$, $10^{\circ}$, $15^{\circ}$ and $20^{\circ}$. The intensity of turbulence was low when pitch angle was $15^{\circ}$ and air volume became peak by 5.08 CMM. It was observed that axis component of velocity increased gradually when pitch angle increased from $0^{\circ}$ to $20^{\circ}$, and embodied noise reduction and improvement of air flow rate through flow stabilization.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.1
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• pp.35-40
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• 2000

Teflon-like fluorocarbon thin film was deposited on various substrates by vapor deposition using PFDA (perfluorodecanoic acid). The fluorocarbon films were characterized by static/dynamic contact angle analysis, VASE (Variable-angle Spectroscopic Ellipsometry) and AFM/LFM (Atomic/Lateral Force Microscopy). Based on Lewis Acid/Base theory, the surface energy ($S_{E}$) of the films was calculated by the static contact angle measurement. The work of adhesion (WA) between de-ionized water and substrates was calculated by using the static contact data. The fluorocarbon films showed very similar values of the surface energy and work of adhesion to Teflon. All films showed larger hysteresis than that of Teflon. The roughness and relative friction force of films were measured by AFM and LFM. Even though the small reduction of surface roughness was found on film on $SiO_2$surface, the large reduction of relative friction farce was observed on all films. Especially the relative friction force on TEOS was decreased a quarter after film deposition. LFM images showed the formation of "strand-like"spheres on films that might be the reason far the large contact angle hysteresis.

• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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• pp.60-67
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• 2009

Purpose: This study was designed to investigate the usefulness of extensile lateral approach for accurate reduction and rigid internal fixation in comminuted intraarticular fractures of calcaneus. Materials and Methods: From October 2002 to May 2007, we managed 55 patients (62 cases) with open reduction and internal fixation using extensile lateral approach. Among these, 38 patients (43 cases) who underwent preoperative and postoperative CT scan were enrolled. All patients were evaluated over 24 months after surgery. Bohler angle and Gissane angle on plain X-ray, displacement and step-off of articular surface of calcaneus on CT scan were measured and we compared the difference between preoperative and postoperative value of them. Clinical results were assessed by using AOFAS Ankle-Hindfoot Scale. Results: The average Bohler angle was restored from $6.8^{\circ}$ to $23.5^{\circ}$ and Gissane angle was improved from $116.4^{\circ}$ to $113.5^{\circ}$ after operation. The average distance of displacement was restored from 4.2 mm to 1.4 mm and step-off of articular surface was recovered from 5.1 mm to 1.3 mm. Clinical results were excellent in 17 cases, good in 18 cases, fair in 3 cases, and poor in 5 cases. 10 cases developed postoperative complications such as skin necrosis, heel pain, limitation of motion of ankle and subtalar arthritis. Conclusion: The extensile lateral approach is valuable for the comminuted intraarticular fractures of calcaneus that enables accurate anatomical reduction and rigid internal fixation by providing direct exposure of subtalar joint.

• Journal of Korean Foot and Ankle Society
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• v.14 no.2
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• pp.157-160
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• 2010

Purpose: The purpose of this study is to find out the correlation factors for prognosis of calcaneal fractures. Materials and Methods: 120 cases (feet) of calcaneal fractures, all of them followed up for more than 1 year after surgical procedures, consisted of 101 men (105 feet) and 13 women (15 feet) were reviewed retrospectively. The collected clinical data were as follows : injury mechanism, surgical procedures, time to procedure, time to work and the radiologic data: Bohler angle, heel width, displacement of posterior facet. AOFAS hindfoot score and VAS score were checked. With ANOVA test and multiple regression analysis, the data processed statistically. Results: According Sanders classification, type II was 37 cases (31%), type III 66 cases (55%), and type IV 17 cases (14%). On plane radiography, the Bohler angle improved to average 28.4 degree from 5.6 degree, and the displacement of posterior facet was corrected to average 1.2 mm. AOFAS hindfoot score was checked average 81.7 points postoperatively, and the meaningful difference existed between types of Sanders classification. The Bohler angle represented the outline of the calcaneus had the better correlation with the clinical outcome of calcaneal fractures rather than the anatomical reduction of the posterior facet did. And the width of calcaneus had good correlation with the clinical score. Conclusion: We should also concern about the outline of calcaneus, the width of calcaneus and the Bohler angle representing anatomical reduction, not only the acute reduction of the posterior facet.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.501-508
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• 2002

The percentage of a mountainous district in our country is comparatively high but the concern for rock mass has been disregarded for a long time. Especially for rock slope, the most important factors are geometric characteristics and their shear strength parameter. In this paper, parametric studies are performed using the distinct element computer program UDEC-BB for rock slopes. Parameters adopted in this paper are joint angle, spacing, persistence, aperture and shear strength parameters (JRC, JCS, basic friction angle). To estimate slope stability, shear strength reduction method is used. The most important factors affecting rock slope stability are joint angle and spacing. The relationship between average displacement calculated by UDEC-BB and safe factor by shear strength reduction method is researched.

• Journal of International Society for Simulation Surgery
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• v.1 no.2
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• pp.71-74
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• 2014

Purpose The prominent mandible angle, otherwise known as "square face", has been recognized as an aesthetic problem that needs correction by many in the Asian community. Many surgeons considered that mandible angle ostectomy alone, brings about hypotrophy of the masseter muscle. However, it was only proven indirectly (by clinical experience and histological animal experiments) and not objectively. In this study, we evaluated the volume of masseter muscle to prove the effect, objectively. Materials and method Computed tomography (CT) images were used to measure the masseter muscle volume of normal female group (n=6), and of female patient group n=8, preoperative and early & late postoperative volumes) presenting the symptom of prominent mandible angle. The data was analyzed statistically by two-sample t-test and paired t-test using SAS (version 8.2). Results In normal female group, volume average was $16,142{\pm}2,829.8mm^3$. In patient group, preoperative volume averaged $24,447{\pm}4,544.5mm^3$ (p<0.0001), early postoperative volume measured average of $31,966{\pm}50,421mm^3$ which is a 30% increase from the preoperative volume (p<0.0001). Late postoperative measurement was $20,202{\pm}4,092.3mm^3$, which is a 20% decrease from the preoperative volume (p<0.0006). Conclusion The bone reduction of prominent mandible angle induce the hypotrophic effect of masseter muscle after long term follow up (5 more months). This result mean that the result of mandible angle contouring surgery can be considered as combined effect of bony angle reduction and subsequent masseter muscle hypotrophy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.648-656
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• 2015

Active SAR satellite's main maneuver is roll axis maneuver to change SAR antenna direction. In addition, yaw steering is required to minimize the doppler centroid variation. Thus, it is resonable to assign the torque/momentum capacity mostly to roll axis and then yaw axis. In this case, the pitch axis shows low agility performance. However, due to orbit maintenance, large angle maneuver about pitch axis is sometimes required. In this paper, we study the pitch axis maneuver time reduction through sequential rotation about roll and yaw axis. Since these two axes have high agility performance than pitch axis, maneuver time reduction is possible when large angle rotation about pitch axis is required.