• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.511-516
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• 2001

Recently small punch creep testing (or miniature disc bend creep test) has received much attention through European collaborative research projects. This method was considered as a substitute for the conventional creep rupture testing by which the residual creep life is measured from the specimen taken out from serviced components of high temperature plants. It would be beneficial if the material creep properties such as power law creep constants as well as the creep rupture life can be measured from the small punch creep test. In this paper a method of assessing creep constants from the small punch creep testing is proposed. Finite element analyses were performed to investigate evolution of stress and strain rate at the weakest locations of the small punch creep specimen. Elastic-plastic-secondary creep analyses were carried out. The estimation equations for creep constants by the small punch creep testing are proposed based on the finite analysis results. Small punch creep tests were also performed with 9Cr steel and the accuracy of the proposed equation was verified by the experimental results.

• 대한기계학회논문집A
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• 제25권9호
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• pp.1493-1500
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• 2001

Recently small punch creep testing (or miniature disc bend creep test) has received much attention through European collaborative research projects. This method was considered as a substitute for the conventional creep rupture testing by which the residual creep life is measured from the specimen taken out from serviced components of high temperature plants. It would be beneficial if the material creep properties such as power law creep constants as well as the creep rupture life can be measured from the small punch creep test. In this paper a method of assessing creep constants from the small punch creep testing is proposed. Finite element analyses were performed to investigate evolution of stress and strain rate at the weakest locations of the small punch creep specimen. Elastic-plastic-secondary creep analyses were carried out. The estimation equations for creep constants by the small punch creep testing are proposed based on the finite analysis results. Small punch creep tests were also performed with 9Cr steel and the accuracy of the proposed equation was verified by the experimental results.

• Neonatal Medicine
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• 제15권1호
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• pp.100-104
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• 2008

난소 낭종은 신생아기 여아의 가장 흔한 복강 내 낭성 종괴로, 대부분은 자연 소멸되지만 일부는 난소 염전, 낭종 내 출혈, 난소 파열 등의 합병증으로 인해 수술적 치료를 필요로 한다. 난소 낭종의 파열은 매우 드물게 발생하는 것으로 알려져 있으며, 심한 혈성 복수나 복막염 등으로 인해 사망을 초래하기도 한다. 저자들은 산전 초음파를 통해 복강내 종괴가 발견되었고 출생 후 경도의 복부 팽만 및 두 차례의 혈뇨를 주소로 내원한 2일된 신생아에서 탐색 개복술을 통해 우측 난소 낭종의 염전 및 파열을 진단하고, 우측 난관-난소절제술을 통해 성공적으로 치료하였기에 문헌고찰과 함께 보고하는 바이다.

• Journal of Chest Surgery
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• 제11권2호
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• pp.232-236
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• 1978

Twenty-two years old male was operated for spontaneous rupture of the esophagus. In the event of perforation, there is nothing to prevent wide spread dissemination, and a devastating necrotizing chemical insult occurrs which is rapidly complicated by anaerobic and aerobic infection which quickly jeopardizes the patient`s life, often with a fatal result. For these reasons and despite modern diagnostic aids, anesthetic and operative technics, and antibiotics, perforation of the esophagus is still an alarming accident. In this case, thoracotomy and surgical closure of the perforation resulted in satisfactory outcome except postoperative fistula, which healed spontaneously.

• Journal of Chest Surgery
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• 제48권5호
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• pp.364-367
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• 2015

Cardiovascular involvement in cases of Behcet's disease is a rare but life-threatening condition, and prosthetic valve detachment is a frequent and serious complication attributable to Behcet's disease following the surgical repair of aortic regurgitation. We report the case of a patient with Behcet's disease presenting with contained aortic rupture around the aortic root. The patient had previously undergone aortic valve surgery three times due to recurrent prosthetic valve detachment. An emergency operation was performed, consisting of aortic root replacement (ARR) using a composite valved conduit and the replacement of the hemiarch. ARR may be an appropriate surgical option for patients with Behcet's disease in order to prevent recurrence of the disease.

• Journal of Chest Surgery
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• 제38권5호
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• pp.400-402
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• 2005

외상으로 인한 횡격막 파열과 그로 인한 신장 이탈은 드문 현상이며, 더욱이 신장 이탈시 신장 다리(renal pedicle)가 완전히 찢어지는 현상은 매우 드물게 발생하며 응급 수술을 시행하지 않으면 생명이 위험할 수 있다. 이에 저자들은 외상성 횡격막 파열과 함께 흉강 내 혈관과 요관이 완전히 찢어진 상태로 신장이 탈출한 1예를 경험하였기에 간단한 문헌 고찰과 증례를 보고하는 바이다.

• Journal of Chest Surgery
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• 제19권4호
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• pp.722-725
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• 1986

Rupture of the main bronchus following closed injury to the chest is a comparatively rare accident. The late recognition of this injury is attended by difficulties in management which may endanger life or expose the patient to distressing months and years of arduous therapy. This case was a 17 year old female who was a high school student. The patient had sustained a crushing injury to her right hemithorax and had been taken to an emergency hospital where right closed thoracostomy had been performed for a tension pneumothorax. She improved following this procedure but massive atelectasis of the right lung developed on the 13th day after trauma and transferred to our hospital. Bronchoscopy disclosed granulation tissue in the right main stem bronchus and end to end anastomosis of the bronchus was performed. Postoperative course was uneventful.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.228-233
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• 2004

The characteristics of the probability distribution for mechanical properties, e.g. tensile strength, reduction of area ana elongation, for STS304 stainless steel in elevated temperature were investigated from tensile test performed by constant cross head speea controls with 1mm/min, Recently, in order to clarify the strengthening mechanisms at high temperature, a new scheme to improve high temperature mechanical properties is desired. Therefore, the test ,technique development of high temperature creep behaviors for this material is very important. In this paper, the creep praperties and creep life prediction by Larson-Miller parameter method for STS304 stainless steel to be used for other high temperature components were presented at the elevated temperatures of 600, 650 and $700^{\circ}C$.

• 한국기계기술학회지
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• 제13권4호
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• pp.125-130
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• 2011

Technological mode progress demands the use of materials at high temperature and pressure. Constant load creep tests have been carried out over the range of stresses at high temperatures. One of the most critical factors in considering such applications as the most critical one is the creep behavior. In order to investigate the creep behavior in this study, the stress exponents during creep were determined over the temperature range of $275^{\circ}C$ to $325^{\circ}C$ and the stress range of 36MPa to 72MPa. The applicability of modified Monkman-Grant relationship was also discussed.

• 한국운동역학회지
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• 제31권4호
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• pp.241-248
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• 2021

Objective: The purpose of this study was to investigate the difference in muscle strength, kinematics, and kinetics between injured and non-injured sides of the leg after Achilles Tendon Rupture surgery during walking and running. Method: The subjects (n=11; age = 30.63 ± 5.69 yrs; height = 172.00 ± 4.47 cm; mass = 77.00 ± 11.34 kg; time lapse from surgery = 29.81 ± 10.27 months) who experienced Achilles Tendon Rupture (ATR) surgery participated in this study. The walking and running trials were collected using infrared cameras (Oqus 300, Qualisys, Sweden, 100 Hz) on instrumented treadmill (Bertec, U.S.A., 1,000 Hz) and analyzed by using QTM (Qualisys Track Manager Ver. 2.15; Qualisys, U.S.A). The measured data were processed using Visual 3D (C-motion Inc., U.S.A.). The cutoff frequencies were set as 6 Hz and 12 Hz for walking and running kinematics respectively, while 100 Hz was used for force plate data. Results: In ATR group, muscle strength there were no difference between affected and unaffected sides (p> .05). In kinematic analysis, subjects showed greater ROM of knee joint flexion-extension in affected side compared to that of unaffected side during walking while smaller ROM of ankle dorsi-plantar and peak knee flexion were observed during running (p< .05). In kinetic analysis, subjects showed lower knee extension moment (running at 2.2 m/s) and positive ankle plantar-flexion power (running at 2.2 m/s, 3.3 m/s) in affected side compared to that of unaffected side (p< .05). This lower positive ankle joint power during a propulsive phase of running is related to slower ankle joint velocity in affected side of the subjects (p< .05). Conclusion: This study aimed to investigate the functional evaluation of the individuals after Achilles tendon rupture surgery through biomechanical analysis during walking and running trials. Based on the findings, greater reduction in dynamic joint function (i.e. lower positive ankle joint power) was found in the affected side of the leg compared to the unaffected side during running while there were no meaningful differences in ankle muscle strength and walking biomechanics. Therefore, before returning to daily life and sports activities, biomechanical analysis using more dynamic movements such as running and jumping trials followed by current clinical evaluations would be helpful in preventing Achilles tendon re-rupture or secondary injury.