• Clinics in Shoulder and Elbow
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• 제1권2호
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• pp.154-159
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• 1998

Medial dislocation of the long head of the biceps brachii is a rare condition that usually occurs in association with tears of the subscapularis, chronic impingement, capsular defects or a fracture of the lesser tuberosity. Less commonly, a biceps tendon dislocation may occur after an acute traumatic event. Following a dislocation, the biceps tendon will assume either an intra- or extra-articular position depending on whether or not the subscapularis tendon detaches from its humeral insertion. Magnetic resonance imaging has been found to provide valuable information concerning the location of the biceps tendon and the integrity of the subscapularis tendon. We present a patient with a traumatic dislocation of the biceps brachii tendon in which the diagnosis remained elusive for an extended period of time. In this case, he was evaluated using MRI and reconstruction was performed by restoring the tendon to its anatomical position.

• Clinics in Shoulder and Elbow
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• 제18권2호
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• pp.61-67
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• 2015

Background: The purposes of the study were to examine rotator cuff tendon degeneration with respect to harvesting location, to determine a rationale for debridement of the torn end, and thus, to determine adequate debridement extent. Methods: Twenty-four patients with a full-thickness rotator cuff tear were included in the study. Tendon specimens were harvested during arthroscopic rotator cuff repair from three locations; from torn ends after minimal regularization of fraying (native end group, NE group), from torn ends after complete freshening of the frayed end (freshened end group, FE group), and from the macroscopically intact portion just distal to the musculotendinous junction (musculotendinous junction group, MTJ group). Control samples were harvested from patients admitted for surgery for proximal humerus fracture. Harvested samples were evaluated using a semi-quantitative grading scale. Results: Mean total degeneration scores in the NE group ($13.3{\pm}3.21$), the FE group ($12.5{\pm}2.30$), and in the MTJ group ($10.8{\pm}3.10$) were significantly higher than those in the normal control group ($5.0{\pm}2.87$; all p<0.001). Mean total degeneration score in the NE group was significantly higher than that in the MTJ group (p=0.012), but was not from that of the FE group. Mean total degeneration score in the FE group was not significantly different from that of the MTJ group. Conclusions: Tendon degeneration exists throughout the entire tendon to the macroscopically intact portion of full-thickness rotator cuff tear. Therefore, aggressive debridement to grossly normal appearing, bleeding tendon is unnecessary for enhancing healing after repair.

• 대한두경부종양학회지
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• 제14권2호
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• pp.206-213
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• 1998

Primary hyperparathyroidism is still uncommomn disease in Korea. However the frequency of this disease has been slowly increased with routine measurement of serum calcium and increasing awareness of hyperparathyroidism in recent years. The diagnosis is established by a persistent elevation of serum calcium and parathyroid hormone and by clinical evaluation. This is a report of eleven patients with primary hyperparathyroidism treated with surgical operation during a period from 1983 to 1997 at Department of Hospital. Authors analyzed the cases to evaluate clinical characteristics and outcome of surgical treatment retrospectively. The result was as follows. 1) In sex distribution, female patients were eight and three were male, the age distribution ranged from 18 to 67 years. 2) The presenting clinical manifestations were renal and urinary stone in eight, bone pain or fracture in six, muscle weakness in four, neurologic symptoms in four, neck mass in three, hypertension in two, and G-I symptoms in one. 3) All patients showed hypercalcemia and elevated serum parathyroid hormone level. 4) Preoperative localization study was performed with computerized tomography, ultrasonography, MRI, arteriography and thyroid scaning. 5) The tumor locations were left lower in eight, left upper in one, right lower in one, and right upper location was one case. 6) Histopathologic findings disclosed adenoma in all cases. 7) All patients were treated by surgical excision and postoperatively transient hypocalcemia occurred in six patients, but no other complication was developed.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.1-9
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• 2005

An end beam is one of the most important structural members supporting uncovered freight under in-service loading. In general, it needs to endure over 25 years. However fatigue fracture has occurred at dynamic stress concentration location of the end beam because user's specifications demanded high speed and vehicle manufacturer made the uncovered freight car with comparatively low strength and stiffness. For durability analysis, finite element analysis is performed to evaluate the problem of uncovered freight structure and local strain. The uncovered freight car was operated on actual problematic railroad line to measure dynamic stress versus time history on the critical part from which a crack is initiated often. Rainflow cycle counting method was used to estimate fatigue damage at dangerous area under operating condition. Therefore, this study shows that analytical fatigue life at the end beam can be predicted on the basis of S-N curve and structure analysis and has a fairly good correlation with experimental fatigue life.

• 대한조선학회지
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• 제9권2호
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• pp.43-48
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• 1972

Inertia friction welding, a relatively recent innovation in the art of joining materials, is a forge-welding process that releases kinetic energy stored in the flywheel as frictional heat when two parts are rubbed together under the right conditions. In a comparatively short time, the process has become a reliable method for joining ferrous, and dissimilar metals. The process is based on thrusting one part, attached to a flywheel and rotating at a relatively high speed, against a stationary part. The contacting surfaces, heated to plastic temperatures, are forged together to produce a reliable, high-strength weld. Welds are made with little or no workpiece preparation and without filler metal or fluxes. However, In order to obtain a good weld, the determination of the optimum weld parameters is an important problem. Especially, because the amount of the flywheel mass will be determined according to the initial rotating velocity values at the constant thrust load, the initial rotating velocity is an important factor to affect a weld character of the inertia-welded IN713C-SAE8630, which is used for the wheel-shafts of turbine rotors or turbochargers, exhausting valves, etc. In this paper, the effects of initial rotational velocity on a weld character of inertia-welded IN713C-SAE8630 was studied through considerations of weld parameters determination, micro-structural observations and tensile tests. The results are as the following: 1) As initial rotating velocity was reduced to 267 FPM, cracks and carbide stringers were completely eliminated in the micro-structure of welded zone. 2) As initial rotating velocity was reduced and flywheel mass was increased correspondingly, the maximum welding temperatures were decreased and the plastic working in the weld zone was increased. 3) As initial rotating velocity was progressively decreased and carbides were decreased, the tensile strengths were increased. 4) And also the fracture location moved out of the weld zone and the tensile tests produced, the failures only in the cast superalloy IN713C which do not extend into the weld area. 5) The proper initial rotating velocity could be determined as about 250 thru 350 FPM for the better weld character.

• 대한조선학회논문집
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• 제45권6호
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• pp.679-687
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• 2008

The fatigue life of ship structure under cyclic loading condition is made up of crack initiation and propagation stages. For a welding member in ship structure, the fatigue crack propagation life is more important than the fatigue crack initiation life. To calculate precisely the fatigue crack propagation life at the critical welding location, the knowledge of the residual stress sensitivity on the fatigue strength is necessary. In this study, thermo elastic-plastic analysis was conducted in order to examine the effect of residual stress on the fatigue crack propagation life. Also the fatigue crack propagation lives considering residual stress were calculated using fatigue crack growth code, AFGROW, on the basis of fracture mechanics. AFGROW is widely used for fatigue crack growth predictions under constant and variable amplitude loading. The reliability of AFGROW on the fatigue of ship structure was confirmed by the comparison of the estimated results with the fatigue propagation test results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권5호
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• pp.567-571
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• 2007

Lateral pharyngeal space is one of potential fascial planes of head and neck, that may become involved by various pathological processes, such as infection, inflammation and neoplasm. The calcified stylohyoid ligament with styloid process is also located in this space, so this space is more acquainted with Eagle's syndrome in oral and maxillofacial field. During the mandibular transbuccal fixation procedures of 29-year old female patient who had right condylar neck and left parasymphysis fracture, we had lost one 10.0 mm miniscrew. After confirming the location of the lost miniscrew from different angled plain skull radiographies, we tried to find it in the lateral pharyngeal space via transtonsillar approach at the time of plate removal operation. This case report is aimed to share our valuable experience of the effective approach way to the lateral pharyngeal space, which has many advantages, such as short operative time, minimal bleeding, fast post-operative recovery, and less morbidity. The related literature is also reviewed.

• 한국해안·해양공학회논문집
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• 제23권4호
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• pp.285-291
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• 2011

이 연구에서는 신형소파블록을 대상으로 실험 및 수치해석을 수행하여 역학적 성능을 평가하고 적절한 보강재의 배근에 따른 구조성능 향상 효과를 검토하였다. 수치해석을 통하여 신형소파블록에 인장응력이 발생하는 위치와 크기를 예측하여 보강재를 설계하였다. 보강재로는 일반 철근 및 해양환경에 적합하도록 부식과 피로에 장점을 지닌 섬유보강재(FRP)를 사용하였다. 실험을 통하여 보강재가 없는 무근 신형소파블록의 파괴하중은 350 kN으로 소파블록의 자중에 비하여 6.2배로 나타났으며, 철근이나 FRP보로 보강한 실험체는 모두 실험의 최고하중인 900 kN 이상의 강도를 보였다. 위험단면을 통과하는 보강재의 개수는 시공의 편의를 위해서는 굵은 지름의 단일 보강재를 사용하는 것이 유리하지만 가는 지름의 보강재 여러 개를 사용하여 균열 폭을 감소시키는 것이 바람직하다는 결과를 얻었다.

• Structural Engineering and Mechanics
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• 제35권5호
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• pp.571-592
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• 2010

An energy-based fatigue life prediction framework was previously developed by the authors for prediction of axial, bending and shear fatigue life at various stress ratios. The framework for the prediction of fatigue life via energy analysis was based on a new constitutive law, which states the following: the amount of energy required to fracture a material is constant. In the first part of this study, energy expressions that construct the constitutive law are equated in the form of total strain energy and the distortion energy dissipated in a fatigue cycle. The resulting equation is further evaluated to acquire the equivalent stress per cycle using energy based methodologies. The equivalent stress expressions are developed both for biaxial and multiaxial fatigue loads and are used to predict the number of cycles to failure based on previously developed prediction criterion. The equivalent stress expressions developed in this study are further used in a new finite element procedure to predict the fatigue life for two and three dimensional structures. In the second part of this study, a new Quadrilateral fatigue finite element is developed through integration of constitutive law into minimum potential energy formulation. This new QUAD-4 element is capable of simulating biaxial fatigue problems. The final output of this finite element analysis both using equivalent stress approach and using the new QUAD-4 fatigue element, is in the form of number of cycles to failure for each element on a scale in ascending or descending order. Therefore, the new finite element framework can provide the number of cycles to failure at each location in gas turbine engine structural components. In order to obtain experimental data for comparison, an Al6061-T6 plate is tested using a previously developed vibration based testing framework. The finite element analysis is performed for Al6061-T6 aluminum and the results are compared with experimental results.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.11-12
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• 2008

Micron-sized Co-alloy T800 powder was coated on Inconel718 (IN718) using high velocity oxygen fuel (HVOF) thermal spraying by the optimal coating process (OCP) determined from the best surface hardness of 16 coatings prepared by Taguchi program. The surface hardness improved 140-160 % from 399 Hv of IN718 to 560-630 Hv by the coating. Porosity of the coating was 1.0-2.7 %, strongly depending on spray parameters. Both friction coefficients (FC) and wear traces (WT) of the coating were smaller than those of IN718 substrate at both $25^{\circ}C$ and $538^{\circ}C$. FC and WT of IN718 and coating decreased with increasing the surface temperature. Tensile bond strength (TBS) and fracture location (FL) of Ti64/T800 were 8,770 psi and near middle of T800 coating respectively. TBS and FL of Ti64/NiCr/T800 were 8,740 psi and near middle of T800 coating respectively. This showed that cohesion of T800 coating was 8,740-8,770 psi, and adhesion of T800 on Ti64 and NiCr was stronger than the cohesion of T800.