• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.77-81
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• 2008

The goal of rotator cuff repairs is to achieve high initial fixation strength, minimize gap formation, maintain mechanical stability under cyclic loading and optimize the biology of the tendon-bone interface until the cuff heals biologically to the bone. Single row repairs are least successful in restoring the footprint of the rotator cuff and are most susceptible to gap formation. Double row repairs have an improved load to failure and minimal gap formation. Transosseous equivalent repairs (suture bridge technique) have the highest ultimate load and resistance to shear and rotational forces and the lowest gap formation. Even though the superior advantages of double row and transosseous equivalent repairs, those techniques take longer surgical time and are more expensive than single row repairs. Therefore single row repairs can be useful in bursal side partial thickness or small size full thickess rotator cuff tear.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.461-462
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• 2011

하천에 침입한 식생이 흐름에 미치는 영향은 현장조사와 수리모형실험을 통해 다양한 연구가 진행되고 있지만 하천의 흐름이 식생에 미치는 영향이나 상호작용에 대해서는 아직 초보적인 수준에 머물러 있다. 국내의 하천에서 버드나무는 일열로 흐름방향에 평행하게 이입되어 활착되는 현상이 두드러지게 나타나고 있고 있으며, 이 연구는 실험실 개수로에 모형 나무를 일렬로 배열하여 식생이 완전히 잠긴 경우와 부분적으로 잠긴 경우에 대하여 수리모형실험을 수행하였다. 수리모형 실험결과 나무의 개수에 따라 수위의 변화가 나타남을 확인할 수 있으며, 빈 공간의 존재를 나타내는 나무의 간격에 따라서도 영향을 받음을 알 수 있었다. 이 연구는 수리모형실험을 통하여 식생의 개수, 잠긴 정도, 흐름 상태에 따른 유속과 수위 분포의 변화를 분석하고자 연구를 수행하였으며 이 결과는 식생저항모형 개발과 이차원 흐름모형의 검보정에 활용할 수 있다.

• Clinics in Shoulder and Elbow
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• v.10 no.2
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• pp.155-159
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• 2007

Arthroscopic single-row rotator cuff repair is a well established surgical technique for the treatment of rotator cuff tears. However, the problem of postoperative retear remains a concern. Various avenues are being explored to address this problem. Some studies have suggested that restoring the anatomical footprint may improve the healing and initial strength of the repaired rotator cuff tendon. The double-row technique was introduced as a method of reconstructing the anatomical footprint. According to biomechanical studies on cadavers, this technique improved mechanical strength and reduced gap formation. However, the biological properties of reattached tendon such as tension, and vascularity have not been proved yet. Furthermore, the apparent mechanical superiority of the double-row over the single-row construction has not resulted in better functional outcomes. Therefore, the less complicated and less costly single-row technique is still the recommended treatment for rotator cuff repairs.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.77-86
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• 2016

A numerical analysis is performed to investigate the effect of a supply channel and jet hole arrangement on the heat flow characteristics of impingement jet. The jet holes in a supply channel are composed of a single or staggered array from the center of a leading edge channel. The software ICEMCFD is used to generate the structured grids for calculation domain and a CFD code CFX 15.0 to perform the simulation. The present solutions are validated by comparison with the experimental and numerical ones of others. A comparison of mass flow rates of impingement jets and Nusselt numbers on the impingement surface for the single or staggered arrays is made.

• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.38-45
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• 2020

Purpose: To examine the clinical and structural outcomes of an at least two-year follow-up of arthroscopic full-thickness rotator cuff repairs with a single-row or suture-bridge technique in patients more than 65 years of age. Materials and Methods: Patients diagnosed with a full-thickness rotator cuff tear who were more than 65 years of age, underwent arthroscopic rotator cuff repair after at least six months of conservative treatment, agreed to take a follow-up magnetic resonance imaging (MRI) six months postoperatively, and visited outpatient for at least two years were enrolled in this study. Clinical evaluations were done using The University of California Los Angeles score, Constant Shoulder Score, and visual analogue scale evaluated two years after the surgery. The structural integrity was analyzed using follow-up MRI. During surgery, a suture-bridge technique was used if the rotator cuff tendon could cover half of the footprint under constant tension. Otherwise, single-row repair was performed. Results: The samples were 158 cases, consisting of 93 single-repairs and 65 suture-bridge repairs. A preoperative comparison of the age distribution, fatty degeneration of supraspinatus and infraspinatus muscle, medial retraction of torn cuff tendon, and tear size between the two groups were not significant. The clinical scores were improved significantly in all cases. The distribution of the structural integrity by Sugaya classification were 49 cases in type 1 (31.0%), 62 cases in type 2 (39.2%), 30 cases in type 3 (19.0%), 11 cases in type 4 (7.0%), and six cases in type 5 (3.8%). The re-tear rate of the single-row group was 9.7% (nine out of 93 cases) and 12.3% (eight out of 65 cases) for the suture-bridge group. Conclusion: Satisfactory clinical and radiological outcomes were achieved after arthroscopic full-thickness rotator cuff repair in patients more than 65 years of age. Both single-row and suture-bridge techniques would be beneficial for the elderly.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2006.03a
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• pp.33-33
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• 2006

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2006.03a
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• pp.31-31
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• 2006

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2009.03a
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• pp.81-81
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• 2009

• Journal of the KSME
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• v.19 no.3
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• pp.190-196
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• 1979

본 강좌에서는 강도와 밀접한 관계를 가지고 있는 파양문제에 대하여, 특히 파괴된 파단면을 중심으로 기초적인 일반사항을 기술해 보고져한다. 그 내용으로는 파괴와 Fractograph, 전자현 미경과 Peplica 법, Shadowing의 유효성, 파괴의 종류와 Fractograph의 일열 및 파단면형성에 관한 기구등이다. 물체가 파괴된다고 하는 것은 외력을 가하면 물체가 2개로 나누어진다는 단 순한 현상이라고 생각되기 쉽지만, 실제로는 물체가 왜, 이렇게 파괴되는가에 대해서는 알 수 없는 것이 대단히 많다. 고체가 2개로 분리되는 macro 현상은 원자배열이나 응집력등과 같은 micro적인 것에 기인하는 복잡한 것들이 있다. 이미 여러분들이 아는 바와같이, 구조물이나 기 계의 파괴는 돌이킬 수 없는 사고에 이르기 쉽다. 작은 부품 1개의 파괴라던지, 강판의 흠이 원 인이 되어 항공기나 선박등의 사고가 생기는 경우가 있다. 금후에는 원자로나 핵융합반응장치 등이 인류의 에너지원으로서 많이 이용될 가능성이 있지만, 파괴사고가 허용되어서는 안된다. 과학기술의 진보와 더불어, 기계 및 구조물에는 보다 가한 재료가 요구되고, 개발되어가고 있다. 따라서 충분히 안전하게 설계되어 있다고 생각할 수 있는 구조라 하더라도 재료내부의 결함을 기점으로 하여 가끔 파괴가 일어남은 부인하지 못할 사실이다.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1442-1446
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• 2004

The heat (mass) transfer characteristics on the blade surface of a first-stage turbine rotor cascade has been investigated by employing the naphthalene sublimation technique. A four-axis profile measurement system is employed for the measurements of the local heat (mass) transfer coefficient on the curved blade surface. The experiments are carried out for two free-stream turbulence intensities of 1.2% and 14.7%. The high free-stream turbulence results in more uniform distributions of heat load on the both pressure and suction surfaces and in an early boundary-layer separation on the suction surface. The heat (mass) transfer enhancement on the suction surface due to the endwall vortices is found to be relatively small under the high free-stream turbulence.