• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.2
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• pp.158-164
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• 2004

Steam generator tubes experience widespread degradations such as stress corrosion cracking, wear, tube rupture, denting, fatigue and so on. The resulting damages can cause tube bursting or leak of the primary water which contains radioactivity Therefore the allowable size of the damage is required to be determined on the maintenance purpose. The burst pressure of a tube with a T-type combination crack consisting of longitudinal and circumferential cracks is obtained experimentally and analytically. Fracture parameters such as stress intensity factor and crack opening angle are investigated. Also the burst pressure for a T-type combination crack is compared with that of a single longitudinal crack to develop a length-based criteria.

• Journal of the Korean Society of Radiology
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• v.84 no.3
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• pp.750-756
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• 2023

Spontaneous arterial bleeding is uncommon, and a mediastinal hematoma caused by spontaneous rupture of the internal thoracic artery has not been reported previously. Patients with liver cirrhosis or heavy alcohol consumption have a higher risk of hemorrhage than those without cirrhosis or excessive alcohol consumption. We present the case of a 39-year-old female with a history of alcoholic liver cirrhosis, who presented with a large mediastinal hematoma attributable to spontaneous rupture of the internal thoracic artery.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.6 no.1
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• pp.1-9
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• 2013

Purpose: The purpose is to perform objective evaluation for rotator cuff using ultrasonography and validate factors influencing cuff integrity as well as efficacy of follow-up ultrasonography after unreamed antegrade intramedullary nailing for humerus fracture. Materials and Methods: Seventeen patients with an average age of $55.7{\pm}18.6$ years underwent antegrade intramedullary nailing for humerus fracture and follow-up ultrasonography of shoulder joint. Mean follow-up period was $43.5{\pm}32.2$ months. Intraoperative evaluation for preoperative cuff tear was performed, of which four cuffs were repaired by single row repair technique. Clinical evaluation included visual analogue scale (VAS), range of motion, Korean Shoulder Scoring System (KSS) and American Shoulder and Elbow Society (ASES) score. Ultrasonographic evaluation was performed on cuff integrity and protrusion of proximal nail tip as well. Radiographic evaluation included time to union, protrusion of proximal nail tip and migration of proximal interlocking screw which could affect shoulder joint function. Results: Mean VAS at last follow-up was $1.65{\pm}1.84$ points. Range of motion showed forward flexion of $137.0{\pm}33.5^{\circ}$, external rotation of $43.5{\pm}12.7^{\circ}$ and internal rotation of $16.4{\pm}2.0^{\circ}$ while KSS score and ASES score were $79.6{\pm}20.7$ and $83.7{\pm}17.0$ points, respectively. Bone union was demonstrated in all cases and average time to union was $3.4{\pm}1.3$ months. Migration of proximal interlocking screw was shown in 6 cases (35%). On ultrasonographic evaluation, there were normal in 8 (47%), weaving in 4 (24%), partial tear in 5 cases (29%), but no complete tear. Protrusion of proximal nail tip was demonstrated in 8 cases (47%) on plain radiographs whereas in 11 cases (65%) on ultrasonography and was associated with increasing age (p=0.038). Ultrasonographic weaving and partial tear was associated with protrusion of proximal nail tip (p=006), but not with repair of preoperative tear (p>0.05). Conclusion: Because weaving and partial tear on ultrasonography originated from protrusion of proximal nail tip, careful insertion of nail and meticulous repair of cuff during operation lead to stable fixation with satisfactory recovery of shoulder function follow-up ultrasonography can be a useful tool for evaluating protrusion of nail tip and rotator cuff tear, of which diagnosis is difficult on plain X-ray after antegrade intramedullary nailing for humerus fracture.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.134-143
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• 2002

According to the result of the experiment, except that Oebal Hanji making, which does not consider the fiber orientation, has a smaller difference between its strength of width and length direction than of Ssangbal Hanii making, there is not a significant difference between Oebal Hanji making and Ssangbal Hanji making. In addition, even though Oebal Hanji making produced indigenous technique is generally felt sturdy because its absolute strength is enhanced by applying fine materials and overlaying several sheets of paper, its relative strength, which is expressed in an index, is not far beyond that of Ssangbal Hanji making Study on the effect of Dochim revealed that Dochim improves remarkably folding endurance and enhances breaking length and the burst strength. Especially, Dochim increase tensile strength. It was also revealed that, indigenous Oebal Hanji making, the higher the number of sheets of paper overlaid is, the higher the tear strength is the increase relatively higher than those of other types of strength. Consequently, Dochim treatment greatly reinforces the imperfect strength of indigenous Hanji. We consider that if we apply Dochim treatment to Ssangbal Hanji making it may bring about abnormal imbalance of strength. We can benefit from the characteristic strength of Oebal Hanji making only when performing paper making and Dochim considering fiber orientation.

• Journal of the Korean Wood Science and Technology
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• v.27 no.1
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• pp.88-104
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• 1999

This study was carried out to classify the Hanjis into three groups that were indigenous Hanji, traditional Hanji, and improved Hanji handmade by paper making method according to the physical properties of each paper sheet such as tensile, bursting and tearing strength, folding endurance and fiber orientation in each layer. The results obtained were summarized as follows: 1. The multi-layered Hanjis made by "Oebal" Hanji making method in different direction of fiber orientation have good properties in tearing resistance. 2. The multi-layered Hanji in different direction of fiber orientation has good properties in the tearing resistance, but the burst index and the breaking length results were lower than the single layered Hanjis. 3. The different fiber orientation and multi-layered method didn't increase, the three indexes(burst index, tear index, breaking length). Only, the different direction of fiber orientation decreased the difference of width and length strength (tensile, tear) of the Hanji. 4. "Dochim"(Korean finishing touch process for indigenous Hanji by fulling round sticks) greatly increase folding endurance(double folds, not $log_{10}$) and good effect to tensile strength and burst strength. 5. The today's Oebal Hanji were the maximum of 2 layers and the indigenous Oebal Hanji were 16 layers the maximum. In addition, average of the indigenous Oebal Hanji was 4 layers(all 4-layer Hanji were the different fiber orientation of each layer). 6, The indigenous Hanji(multi-layered, and different fiber orientation) was good condition with "Dochim". Dochim increased tensile strength and burst strength of the indigenous Hanji. So the three-strength indexes were similar level("--"). 7. When the number of layer which were same fiber orientation increase, the increased Hanji became similar strength pattern("V", breaking length and burst index was higher than tear index) with "Ssangbal" Hanji. 8. The single layered papers that made by "Oebal" Hanji making method were similar strength pattern with Ssangbal Hanji. 9. There was no way to find the width and length direction of multi-layered Hanji by comparison between the difference of tensile strength and the difference of tearing resistance. 10. The compared pattern of tensile strength and tearing resistance of indigenous Oebal Hanji was different from today's Oebal Hanji. Especially, the tearing resistance of all indigenous Oebal Hanji(16 samples) was stronger on width of tearing resistance. And in the half of indigenous Oebal Hanji samples, the width of tensile strength and tearing resistance was stronger than length strength (Indigenous Oebal: '$\ulcorner\lrcorner$' 50%, '$\bigcup$' 50% $\leftrightarrow$ Today's Oebal: '$\ulcorner\lrcorner$' 12%, '$\bigcup$'6%, '$\llcorner\urcorner$'17%, '$\bigcap$'65%). In 65% today's Oebal, the length direction of tensile strength and tearing resistance was stronger than the width direction.

• Journal of Chest Surgery
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• v.38 no.10 s.255
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• pp.693-698
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• 2005

Background: Sinus valsalva aneurysm (SVA) is a rare disease, and it is frequently accompanied by ventricular septal defect and aortic valve regurgitaion. For treatment of SVA, several surgical mordalities were applied, but there was no report on the long-term result after surgical repair in Korea. We reviewed our 28 years of experiences and analyzed the long-term results after treatment of sinus valsalva aneurysm with or without rupture. Material and Method: Between March 1974 and February 2002, 81 patients were operated under the impression of sinus valvsalva aneurysm or sinus valsalva aneurym rupture. Retrospectively we reviewed the patients' record. Mean age of patients was $29.2\pm11.5$ and there were 49 males. Accompanyng diseases were as follows: VSD in 50, PDA in 2, Behcet's disease in 2, TOF in 1, RVOTO in 1, AAE in 1. Seventy-seven $(95\%)$ patients had sinus valsalva rupture and in 14 patients, subacute bacterial endocarditis was accompanied. Degree of aortic valve regurgitation was as follows: grade I: 8, II: 10, III: 9, IV: 4. Most common rupture site was right coronary sinus (66 patients, $81\%$) and most common communication site was right ventricle (53 patients). In repair of sinus valsalva rupture, patch was used in 37 patients, and direct suture was done in 38 patients. Result: There was one surgical death $(1.2\%)$. Follow up was done in 78 patients $(97.5\%)$, mean follow up period was $123.3\pm80.9(3\~330\;months)$. During the follow up period, 3 patients died $(3.8\%)$. One patient died of heart failure, another patient died of arrhythmia and the other one died of unknown cause. In two patients, complete atrio-ventricular block was developed during follow up period, and there was no operation related event or complication. Kaplan-Meier survival analysis revealed $92.5\pm3.5\%$ survival at 15 and 27 years and it seems to be satisfactory. Conclusion: Long-term surgical results and survival is satisfactory after repair of sinus valsalva aneurysm with or without rupture.

• Investigative Magnetic Resonance Imaging
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• v.18 no.3
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• pp.219-224
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• 2014

Purpose : To determine the incidence of truncated triangle appearance of anterior horn (AH) to body of medial meniscus (MM) and determine its clinical significance. Materials and Methods: IRB approval was obtained, and informed consent waived for this study. The criteria of "pseudoradial tear" was truncated triangle appearance of the tip of AH to body of MM on one or more coronal images with adjacent fluid signal intensity at the blunted tip. Two musculoskeletal radiologists retrospectively evaluated 485 knee MR images independently for the presence and number of sections with "pseudoradial tear" of AH to body of MM using proton density-weighted coronal MR images. Inter-and intraobserver agreement was calculated using kappa coefficients. Medical records were reviewed for arthroscopic correlation. Results: A pseudoradial tear in the AH to body of MM was present in 381 (78.6%) patients. Locations were 112 in AH (29.4%), 143 in AH to body (37.5%), and 126 in body (33.1%). Number of consecutive sections of pseudoradial tear were 1 in 100 (26.2%), 2 in 164 (43.0%), 3 in 94 (24.7%), 4 in 21 (5.5%), and 5 in 2 (0.5%). Interobserver agreement was 0.99 for presence and 0.43 for number of sections of pseudoradial tear. Arthroscopies were performed in 96 patients and none of the pseudoradial tears were proven as true radial tears on arthroscopy. Conclusion: Pseudoradial tears are frequently seen in AH to body of MM on coronal MR images and may be another pitfall that a radiologist needs to be aware of and be able to differentiate from true radial tear.

• Clinics in Shoulder and Elbow
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• v.4 no.1
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• pp.17-23
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• 2001

There has been considerable controversy concerning the methods for treatment of dislocation of the acromioclavicular joint, especially in grade III injury. The authors have treated 24 cases of the complete dislocation of the acromioclavicular joint from January 1990 to July 2000. We performed 14 cases of coracoclavicular wiring operation, 10 cases of modified Phemister operation and compared the results and complication of wiring operation with modified Phemister. The clinical results in modified phemister operation were excellent in 8 cases(80%), good in 1 case(l0%), fair 1 case(10%). In wiring operation, excellent is 11 case(78%), good is 2 case(14%), fair is 1 case(14%). The complications of modified Phemister operation were breakage and migration of K-wire in 2 cases. In wiring operation, breakage of wire was in 2 cases but migration was not showed. We prefered coracoclavicular wiring operation for dislocation of acromioclavicular joint of active young adults because of the following advantages: 1) violation of acromioclavicular joint can be avoided but rotation of the clavicle was not restricted. 2) The operation is simple to perform. 3) Postoperative immobilization is minimal. 4) Removal of the wire is easy because wire was not migrated when breakage of wire was occured.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.367-375
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• 2014

Recently the use of concrete post-installed set anchors has been increasing because this constructing method is flexible and easy to attach or fix structural members when we repair, reinforce, or remodel a concrete structures. Depending on the shear strength of steel, the strength of concrete, edge distance and anchor interval, etc, the anchor loaded in shearing exhibits various failure modes such as steel failure, concrete failure, concrete pryout. In this study, the objective is to investigate the effects of the variations like anchor embedment depth, anchor interval, edge distance and concrete strength on the shear failure behavior of post-installed concrete set anchor embedded in concrete. The results of embedment depth experiments show that concrete strength has much effection on the shallow embedment depth. Steel failure occur to all results of the anchor interval experiments, but concrete is failed when edge distance experiments that less than the embedment depth. Through the comparision of the same parameters experiments results show that as strong as concrete strength are the displacement results are small.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.3
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• pp.52-62
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• 1994

기계나 구조물 파괴의 대부분은 노치부를 기점으로 하여 발생하기 때문에 첨단복합재료를 노지부 재로서 안전하면서도 경제적으로 사용하기 위해서는 각종 조건하에 있어서 강도특성을 명확히 하는 것은 대단히 중요하다. 본 연구에서는 노치를 갖는 복합재료를 이용하여 각종조건하에서 강도특성평가실험을 행하였으 며, 얻어진 결과를 종합하면 다음과 같다. (1) 첨단복합재료 노치재는 試驗片의 幾可學的 形狀과는 관계없이 노치반경 p만에 의해 결정되는 최대탄성응력 $\sigma_{max}$일정의 條件下에서 破t짧된다. (2) 破斷時 최소단면에서의 공칭응력 $\sigma_{c}$와 응력집중계수 $K_{t}$와의 관계에 있어서,$\sigma_{c}$의 값이 $K_{t}$의 증대와 더불어 떨어지고 있는 부분과, $K_{t}$와 관계없이 거의 일정하게 되고 있는 부분으로 나누어지는 現象은 노치재의 回轉굽힘 또는 인장압축파열에서 보여지는 현상과 外觀上 對應하고 있다. 즉, 정적파괴와 피로파괴는 파괴의 양상이 비슷하다 (3) PEN수지단체의 경우, 피로균열발생은 점발생적 피로균열이 최대탄성응력에 의해 지배되며, 노치에 만감하며,균열전파수명은전수명에 비해 상당히 짧다. (4) 단탄소섬유강화복합재료의 경우, 피로균열은 섬유端에 응력이 집중하기 때문에 일반적으로 섬유端에서 아주 빠른 시기에 발생하지만, 섬유가 피로균열진전에 대해 방해물로 작용하기때문에 아주 천천히 전파한다. (5) 短탄소鐵維는 피로균열발생에 대해서는 負의 강화작용 전수명의 극히 초기단계에 피로균열 발생을, 피로균열전파에 대해서는 正의 강화작용을 한다. (6) 단탄소섬유를 PEN에 강화함으로 인해 정적강도 보다 피로강도에 더 큰 강화효과를 초래했으며, 선형노치역학의 개녀은 첨단 복합재료의 강도평가에 대단히 유효했다.