• Archives of Metallurgy and Materials
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• 제64권2호
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• pp.613-616
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• 2019

The objective of the present research is to develop the novel multi-compaction technology to produce hybrid structure in powder metallurgy (P/M) components using dissimilar Fe-based alloys. Two distinct powder alloys with different compositions were are used in this study: Fe-Cr-Mo-C pre-alloyed powder for high strength and Fe-Cu-C mixed powder for enhanced machinability and lower material cost. Initially, Fe-Cu-C was pre-compacted using a bar-shaped die with lower compaction pressure. The green compact of Fe-Cu-C alloy was inserted into a die residing a half of the die, and another half of the die was filled with the Fe-Cr-Mo-C powder. Then they subsequently underwent re-compaction with higher pressure. The final compact was sintered at 1120℃ for 60 min. In order to determine the mechanical behavior, transverse rupture strength (TRS) and Vickers hardness of sintered materials were measured and correlated with density variations. The microstructure was characterized using optical microscope and scanning electron microscope to investigate the interfacial characteristics between dissimilar P/M alloys.

• Archives of Plastic Surgery
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• 제37권5호
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• pp.650-658
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• 2010

Purpose: In the case of repair for far distal parts of FDP (Flexor digitorum profundus) division, the method of either pull-out suture or fixation of tendon to the distal phalanx is preferred. In this paper, the results of a modified loop suture technique used for the complete division of FDP from both zone 1a and distal parts of zone 1b in Moiemen classification are presented. Methods: From July 2006 to July 2009, the modified loop suture technique was used for the 10 cases of FDP in complete division from zone 1a and distal parts of zone 1b, especially where insertion sites were less than 1 cm apart from a tendon of a stump. In a suture technique, a loop is applied to each distal and proximal parts of tendon respectively. Core suture of 2-strand and epitendinous suture are done with PDS 4-0. Out of 10 patients, the study was done on 6 patients who were available for the followup. The average age of the patients was 49.1 years (in the range from 26 to 67). 5 males and 1 female patients were involved in this study. There were 3 cases with zone 1a and distal parts of zone 1b. The average distance to the distal tendon end was 0.6 cm. There were 5 cases underwent microsurgical repair where both artery and nerve divided. One case of only tendon displacement was presented. The dorsal protective splint was kept for 5 weeks on average. The results of the following tests were measured: active & passive range of motion, grip strength test, key pinch and pulp pinch test. Results: The follow-up period on average was 11 months, in the range from 2 to 20 months. There was no case of re-rupture, but tenolysis was performed in 1 cases. In all 6 cases, the average active range of motion of distal interphalangeal joint was 50.8 degree. The grip strength (ipsilateral/contralateral) was measured as 88.7% and the pulp pinch test was 79.2% as those of contralateral side. Flexion contracture was presented in 2 cases (15 degree on average) and there was no quadrigia effect found. Conclusion: Despite short length of tendon from the insertion site in FDS rupture in zone 1a and distal parts of zone 1b, sufficient functional recovery could be expected with the tendon to tendon repair using the modified loop suture technique.

• 보존과학회지
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• 제34권3호
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• pp.157-166
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• 2018

본 연구에서는 아교의 접착 특성 향상을 위해 가교제(Cross-linking Agent)를 첨가하는 방법으로 젤라틴 결합력을 증대하였다. 제니핀 첨가 아교는 물성 측정, 구조 분석, 색잔류도, 용출도, 파단강도를 측정하였으며, 수분과 자외선에 대한 내수성과 내광성을 비교하였다. 연구 결과 겔강도와 점도는 제니핀 첨가량에 따라 증가하였다. 구조분석 결과, 젤라틴에서는 구조적으로 안정된 콜라겐의 3중 구조의 흡수 피크가 관찰되었다. 색잔류도 결과, 명도가 낮아지기 때문에 피막이 관찰되는 것으로 판단된다. 용출량은 $50^{\circ}C$ 증류수에서 제니핀 첨가량이 증가할수록 용출된 아교 양이 증가하였고 파단강도는 제니핀 첨가량에 따라 증가하였다. 내수성과 내광성은 제니핀 첨가에 따른 열화 전 후 양상이 나타나지 않았다. 본 연구 결과를 바탕으로 제니핀 첨가 아교의 접착 특성을 확인할 수 있었으며 아교에 적용 가능한 실험 방법을 고찰하였다. 제니핀을 첨가한 후에도 아교 고유의 특성인 유연성, 재용해성, 접착력, 경화속도가 사라지지 않고 향상되기 때문에 균질한 아교가 확보된다면 문화재 보존 및 아교 제작에 적용이 가능할 것으로 기대한다.

• 한국가스학회지
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• 제22권3호
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• pp.1-6
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• 2018

신뢰도기반 설계 및 평가(RBDA) 방법론은 천연가스 배관을 설계하는 최신의 방법 중 하나이다. 신뢰도 목표는 설계와 유지관리 단계에 걸쳐 관계된 한계상태을 충족하는 안전수준을 가지는 지 확인하기 위해 사용된다. 목표 신뢰도는 대누출과 파단과 같은 극한한계상태에 대한 개인적 위험과 사회적 위험에서 사용하는 허용 가능한 위험수준을 적용하여 개발되었다. 본 논문에서 신뢰도 목표는 배관의 생애주기 동안 주기적인 유지관리를 적용함으로써 충족할 수 있음을 보여준다. 사례분석은 국내 천연가스 수송배관에 대한 굴착공사에 따른 손상확률 계산, 부식에 따른 손상확률의 계산, 그리고 재검사 주기의 추정을 포함한다.

• Journal of Chest Surgery
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• 제9권2호
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• pp.251-264
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• 1976

Forty three patients with disease of the aorta were admitted in this department during the period from beginning of 1956 to the end of 1976. They consisted of eighteen cases of aortic aneurysms, eight cases of Takayasu's arteritis, eight Leriche syndromes, six dissecting aneurysms, two aortic coarctations and one case of vascular ring. Of eighteen aortic aneurysms, twelve were operated resulting in eight survivors. Three of four mortalities were in shock preoperatively because of aneurysmal rupture. Among six dissecting aortic aneurysms, four were type III and two were type I according to DeBakey's classification. For the purpose of relief of acute arterial insufficiency in the lower extremities, a re-entry operation grafting a Y-shaped dacron vessel between abdominal aorta and common iliac arteries was performed. The patient regained consciousness soon after the operation and was well until postoperative second day, when severe convulsion developed abruptly and died. And in a chronic case of type III dissecting aneurysm, a dacron graft bypass shunt between ascending aorta and lower descending thoracic aorta with resection of the aneurysm was performed, but acute severe aortic insufficiency developed soon after the operation and fell into intractable heart failure resulting in death. The cause of the aortic insufficiency seems to be retrograde dissection from the proximal anastomosis site in the ascending aorta. Three cases were treated medically with Wheat's regimen. Two of them survived with relief of symptoms. Eight patients of Takayasu's arteritis were all females and aged between twenty and forty-four averaging twenty nine. Bypass graft operation between aortic arch and carotid arteries using Y-shaped nylon prostheses were performed in three patients resulting in death in two cases postoperatively due to severe cerebral arterial insufficiency during the procedure. All the patients with Leriche syndrome were males and over forty. In two cases, bypass graft with Y-shaped dacron vessel between terminal aorta and common iliac or femoral arteries were performed with good result. Thromboembolectomy or thromboendarterectomy was employed in three patients, of whom one was aggravated in sexual problem postoperatively. One out of two aortic coarctations and a vascular ring were treated surgically with excellent results.

• Clinics in Shoulder and Elbow
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• 제9권2호
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• pp.181-188
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• 2006

Purpose: To evaluate the integrity of repair & technical tip in use of Massive Cuff Stitch at arthroscopic repair of rotator cuff tear. Materials and Methods: Twenthy-nine cases of arthroscopically repaired full thickness tear of rotator cuffs which are medium sized were evaluated. Between December 2004 to September 2005 we have studied, the average age 53($42{\sim}69$) years old, mean follow-up was 15($12{\sim}21$) months. We analyzed the results statistically by paired t-test. The integrity of repair were verified by follow up MRI which were checked 11 cases and ultrasound which were checked 10 cases. Results: VAS of pain improved preoperative average 7.1 to postoperative 0.9, ADL improved 11.2 to 25.6 respectively, UCLA improved 13.7 to 32.9(all, P<0.05). 89.7% showed excellent & good results at the final follow-up. The satisfied rate was 93.1%(27 cases). There was re-rupture of the repaired rotator cuff in one case out of 11 cases which were checked by MRI, and in one case out of 10 cases which were checked by ultrasound, and there was one case of thinning of cuff which were checked by ultrasound. Conclusion: The use of Massive Cuff Stitch in arthroscopic repair of rotator cuff tear have been reduced technical failure. It will be good surgical technique which maintain the integrity of repairs.

• 한국경제지리학회지
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• 제22권4호
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• pp.381-404
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• 2019

본 논문은 북한 이탈주민을 대상으로 한 설문조사와 심층 면담 결과를 활용하여 북한 내 여러 경제주체들이 경제위기에 어떻게 대응해왔고 이를 통해 나타나는 다양한 경제관행들이 공간성과 어떻게 얽혀 있는지를 규명하는데 목적이 있다. 본 논문은 북한의 시장화를 경제지리학에서 최근 논의되고 있는 '길들이기' 관점에서 바라볼 필요가 있음을 주장하고자 한다. 이와 같은 관점에서 북한의 시장화를 이해할 때 우리는 시장화를 헤게모니 권력을 갖는 거대 프로젝트로서 '저편에 놓여 있는' 무엇이 아니라 공간 내 다양한 경제주체들이 일상생활의 관행을 통해 끊임없이 (재)구성하고 있는 것으로 설명할 수 있다. 경제적 위기와 파열, 경제적 주변화에 대한 경제주체의 대응전략은 경제와 비경제가 절합되어 있는 관점에서 파악할 수 있다. 구체적으로 본 논문은 일상생활의 다양한 대응전략이 경제적, 비경제적 요인들에 의해 중층결정되어 있으며 관행의 효과성은 권력관계에 따라 차별적으로 나타나고 있음을 강조한다.

• Archives of Plastic Surgery
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• 제40권1호
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• pp.28-35
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• 2013

Background If a chronically infected abdominal wound develops, complications such as peritonitis and an abdominal wall defect could occur. This could prolong the patient's hospital stay and increase the possibility of re-operation or another infection as well. For this reason, a solution for infection control is necessary. In this study, surgery using a rectus abdominis muscle myofascial splitting flap was performed on an abdominal wall defect. Methods From 2009 to 2012, 5 patients who underwent surgery due to ovarian rupture, cesarean section, or uterine myoma were chosen. In each case, during the first week after operation, the wound showed signs of infection. Surgery was chosen because the wounds did not resolve with dressing. Debridement was performed along the previous operation wound and dissection of the skin was performed to separate the skin and subcutaneous tissue from the attenuated rectus muscle and Scarpa's fascial layers. Once the anterior rectus sheath and muscle were adequately mobilized, the fascia and muscle flap were advanced medially so that the skin defect could be covered for reconstruction. Results Upon 3-week follow-up after a rectus abdominis myofascial splitting flap operation, no major complication occurred. In addition, all of the patients showed satisfaction in terms of function and esthetics at 3 to 6 months post-surgery. Conclusions Using a rectus abdominis myofascial splitting flap has many esthetic and functional benefits over previous methods of abdominal defect treatment, and notably, it enabled infection control by reconstruction using muscle.

• Journal of Chest Surgery
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• 제22권6호
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• pp.1001-1012
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• 1989

In 1968, Carpentier and his associates introduced glutaraldehyde as a compound for preparing cardiac tissue valve, and this technique has provided a considerably more suitable and durable tissue valve substitute. To increase further durability of valve tissue, Reis and his colleagues designed a flexible stent to reduce the stress on the heterogeneous tissue valve mounted. However with the advent of more innovative mechanical valve currently, many bioprosthetic valves are being substituted by mechanical valves at our department of cardiothoracic surgery because of bioprosthetic valve failure. Main cause of bioprosthetic valves failure were calcification or/and tear of tissue valves. The purpose of this retrospective study is to clarify the relationship between the patients clinical profile during implantation of tissue valves and pathologic features of the failed bioprosthetic valve. From March, 1982 through June, 1988, 53 bioprosthetic heart valves that had been ex-planted from 45 patients at the department of cardiac surgery of Yonsei University Hospital were subjected to this study. The patients were 10 to 65 year-old [mean age: 30.3 yr] with 17 males and 28 females. Re-replacements of prosthetic valves were carried out twenty nine in mitral position, eight in aortic position and eight in both aortic and mitral position simultaneously. The grading and location for calcification of valves were verified by radiograms. The calcification of the explanted valves leaflets was graded from 0 to 4 plus according to Cipriano and associates method. The types of tear and perforation of leaflet were classified into four types as Ishihara has adopted initially in 1981. In younger age group under thirty three years, explanted tissue valves were significantly more affected in terms of grades of severity of valve calcification as compared with older age group [p < 0.035]. Valve calcification appeared more severe in male as compared to female [p< 0.002]. Ionescu-Shiley bovine pericardial bioprosthetic valves showed more severe calcification than Hancock porcine tissue valves [p< 0.035]. Calcium deposit was found very prevalent at the area of commissural attachment [86 % of all]. Type I of valve rupture was shown to be related with simultaneous calcification. However, the relation of explanted valve position, duration of implanted prosthetic valve, atrial fibrillation and anticoagulant therapy to the severity of bioprosthetic valve calcification were not significantly clear statistically [p > 0.05].

• Journal of Chest Surgery
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• 제30권11호
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• pp.1149-1153
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• 1997

재팽창성 폐부종은 만성적으로 허탈된 폐를 흉강 삽관술이나 늑막 천자술에 의해 급속히 재팽창시킬 때 발생하는 드문 합병증이다. 이는 또한 폐허탈 기간이 참거나 흉강내 흡인술의 적용없이도 발생할 수 있다. 저자들은 거대 종격동 흉선낭종의 절제술후 동반되어 발생한 재팽창 폐부종을 경험하였다. 환자는 26세 여자로 결핵성 흡수로 오인된 거대 종격동 낭종에 의해 장기간 폐허탈이 동반되어 있었다. 흉수배액을 위한 폐쇄식 흉강삽관술로 유발된 낭종의 파열로 농흉이 합병되었다. 저자들은 파열된 흉선낭종과 농홍을 성공적으로 수술 치험하였고, 낭종 절제술후 병발된 재팽창성 폐부종에대해 약물요법과 호기말 양압법을 이용한 기계호흡으로 치료하였다. 환자는 이후 특별한 합병증없이 건강히 퇴원하였다.