• Fire Science and Engineering
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• v.17 no.4
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• pp.124-130
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• 2003

This research focuses on analysis of a interaction fracture of various glasses due to contact of water sprayed curtain on hot glass surface with high temperature produced from convective heat source near glass wall. A large scaled experimental test was done in order to find the range of the glass surface temperature to be able to cause the breakage of the glasses when water droplets reach on the hot surface. This paper shows the allowable temperature of the glass surface for prevention of the cooling down breakage before water curtain droplets contact the surface. Allowable Temperature if $250^{\circ}C$ for the tempered glass but general glass is very relatively low. Therefore if the water curtain spray system was adequately activated by a thermal detector installed below ceiling adjacent glass wall with water curtain nozzle system, all hot glass would not break out by cooling water droplet's contact on the hot surface due to convective heat released by adjacent fire source near the glass wall.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.607-612
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• 1997

Between March 1963, and December 1994, fifty-three patients with a ruptured aneurysm of sinus of Vasalva(RSV) were operated. The RSV originated from the right coronary sinus in 43 patients(81%), from the non coronary sinus in 7 patients(13%), and from combined sinuses in 2 patients. The RSV from the right coronary sinus mainly drained to the right ventricle(81.4%), and the RSV from the non coronary sinus mainly drained to the right atrium(71.4%). Recently, we are using patch to repair the RSV through a double approach. During the operation, concomitant . procedures were performed; 32 Patch repairs of VSD, 14 aortic valvuloplasty, 10 aortic valve replacement, 2 tricuspid valvuloplasty, and one Bentall's procedure. During the follow up period between 1 and 31 years(mean 8 years, 94% follow up), there were 2 late deaths and 14 late complications. Actuarial 10-year survival rate .was 95%, and 10-year actuarial freedom from late event was 53 %. Factor analysis revealed that the combined SBE is a risk factor of late event. Actuarial freedom from failure of aortic valvuloplasty was 55% at 9 years. Although surgical repair of RSV achieved excellent long term survival, aortic regurgitation and endocarditis revealed significant risk factor in long-term results. Therefore, more attention should be required in patients of RSV associated with aortic regurgitation or endocarditis.

• 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.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.254-261
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• 2018

Purpose: Favorable results have been reported after the direct repair of chronic ulnar collateral ligament ruptures of the thumb metacarpophalangeal (MP) joint, but the results for radial ligament seem rather controversial. The purpose of this study is to compare the results of ligament reattachment between chronic rupture of the ulnar and the radial collateral ligament (RCL) of the joint. Methods: We reviewed retrospectively the radiologic and clinical results of ligament reattachment with suture anchors for chronic (more than 6 weeks) rupture of the collateral ligament of the thumb MP joint with averaged 22-month follow-up. The data between 6 radial and 8 ulnar ligament repairs were compared statistically. Results: The average of postoperative ulnar deviation angle was $13.3^{\circ}$ in radial ligament and $2.0^{\circ}$ in ulnar ligament (p=0.020) in the last follow-up plain X-ray. Postoperative ligament instability was positive in 4 out of the 6 radial repairs and no case with instability was observed in ulnar ligament. In postoperative follow-up, sustained joint subluxation was observed only in 2 out of the 6 radial repairs. Conclusion: The delayed repair of the RCL of the thumb MP joint resulted in less favorable outcomes and ligament instability was observed postoperatively in more than half of the cases.

• 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.

• Composites Research
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• v.36 no.2
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• pp.132-139
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• 2023

A linerless composite propellant tank was designed and manufactured by using the carbon fiber-reinforced composite materials which have superior strength-to-weight ratio in order to reduce weight of the tank. In this research, we designed a sub-scale composite propellant tank with a diameter of 800 mm to withstand an MEOP of 1.7 MPa. We manufactured the boss of the tank by using the same composite materials to reduce the thermal expansion difference between the boss and the secondary-bonded composite layers of the barrel in the cryogenic environment. We used the collapsible mandrel to manufacture the tank without any liner. The mandrel was made from epoxy-based composite tooling prepregs to reduce weight of the mandrel. We manufactured the test tanks by laying up the carbon fiber fabric prepregs manually on the mandrel and then applying the autoclave cure process. We performed a proof test, a helium tightness test, a repeated pressurization test, and a burst test in room temperature. The test results demonstrate that the proposed design and manufacture process satisfies all strength requirements as well as an anti-leakage requirement.

• Clinics in Shoulder and Elbow
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• v.14 no.2
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• pp.229-235
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• 2011

Purpose: To compare the clinical and radiological result of arthroscopic Mattress Locking suture repair to that of a Simple suture repair with small and medium-sized rotator cuff tears. Materials and Methods: Among 92 patients who were followed up after arthroscopic repair in patients with small and medium-sized rotator cuff tear from April 2007 to October 2010, 27 patients who took Arthroscopic Mattress Locking suture were set as group I and 65 patients who took Simple suture were set as Group II. The average age of patients were 58 years old and average follow-up period was 30 months. For analysis, VAS, ASES and KSS were used to analyze the range of joint movement and pain. And, for the image result, MRI performed after operation were evaluated. Results: The average VAS, KSS, UCLA score and ASES prior to surgery improved in the last follow-up (p<0.001), while was no difference in two groups (p>0.001). In MRI follow-up examination, the 2 cases (7.41%) of group 1 showed increased rupture lesions with improved symptoms. And the 12 cases (18.47%) of group 2 showed increased rupture lesions with improved symptoms. Retears in the group I were significant less than the group II (p<0.001). Conclusion: Comparing patients with small and medium-sized rotator cuff tear who took arthroscopic mattress locking suture repair to those who took simple suture repair after over one year follow up period, the clinical result showed no significant difference between two groups. However, Mattress Locking suture repair showed excellent radiological result compared to simple suture repair when comparing rerupture.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.3
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• pp.344-352
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• 1983

격납 용기 내에 비응축성 가스(공기)가 존재하는 경우에 증기의 응축 열전달 계수를 평가하는 방 법을 연구하였다. 유일한 대규모 격납 용기 실험인 CVTR자료를 이용하여 응축 열전달 계수를 계산하여, 현재 원자력 발전소의 냉각재 상실 사고(LOCA) 및 주 증기 배관 파열사고(MSLB)시에 격납 용기의 안전 해석에서 공식적으로 사용되고 있는 Tagami와 Uchida열전달 계수 관계식과 비교해 본 결과 좋은 일치를 보여 주었다.

• Journal of the Korean Arthroscopy Society
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• v.14 no.1
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• pp.49-52
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• 2010

Purpose: We introduce arthroscopically assisted mini-open rotator cuff repair using anterolateral approach. Operative Technique: Placing lateral decubitus position on general anesthesia, a standard arthroscopic glenohumeral examination is performed to evaluate lesions of shoulder joint through posterior and anterior portal. And then arthroscope is placed in the subacromial space and we evaluate the size of the torn tendon and perform arthroscopic acromioplasty through lateral portal. A 3 to 4 cm skin incision is performed from anterolateral edge of acromion to distal and dissected along to raphe between anterior and middle deltoid. A deltoid retractor is then placed, allowing direct visualization of the rotator cuff and humeral head. As torn tendon is tagged by traction suture, we try to anatomical reduction on the footprint and then perform single row or double row repair of the rotator cuff using suture anchors. To prevent avulsion of the deltoid from the acromion, additional sutures by bone tunnel with acromion and deltoid is performed. Conclusion: This technique is useful procedure to get direct approach to anterior portion of supraspinatus tendon and to need lesser deltoid retraction than portal extension approach due to dividing along to raphe between anterior and middle deltoid. Also it provide better visualization of the superior portion of subscapularis and infraspinatus.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.439-442
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• 2009

In this study, the residual strength of CFRP filament winding pressure vessel after low velocity impact was evaluated quantitatively. After impact test, the pressure vessel was sectioned to produce 25 mm-wide ring specimen and the bursting pressure of this specimen was measured. A finite element model was also fabricated to investigate the deformation and stress distribution characteristics of the impacted CFRP vessel. The degradation of the residual strength along with the increase of impact energy was successfully measured and reviewed.