• 한국포장학회지
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• 제27권3호
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• pp.169-174
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• 2021

우리나라가 1인당 플라스틱 년간 소비량이 132 kg(2019)으로 세계1위로 나타났고, 지구온난화와 탄소중립을 위한 국제적 협약이 진해되고 있으며 소비자들도 바이오플라스틱에 대한 관심과 니즈가 증가하고 있어, 바이오플라스틱 소재에 복합 사용화 첨가제를 농도별로 첨가하여 필름을 생산 시 토출량, 용융지수, 인장강도 변화를 조사하였다. 석유계 수지인 LLDPE와 LDPE보다 PLA와 PBAT에서 용융지수가 현저히 높은 것으로 나타났으며 동일 수지나 동일 처리구에서는 heating temperature가 증가함에 따라 용융지수가 증가한 것으로 나타났다. 상용화제 4%를 첨가한 BDP-2 처리구에서 토출양도 비중도 우수한 것으로 조사되었으며, MD 및 TD 방향의 인장강도도 높게 나타나 BDP-2가 복합화 생분해 필름 제조용 제조 방법으로 가장 적합한 것으로 사료되었다.

• Archives of Plastic Surgery
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• 제45권3호
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• pp.246-252
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• 2018

Background Slim patients or those with large breasts may be ineligible for breast reconstruction with an abdominal flap, as the volume of the flap may be insufficient. This study aimed to establish that abdominal tissue-based breast reconstruction can be well suited for Korean patients, despite their thin body habitus. Methods A total of 252 patients who underwent postmastectomy breast reconstruction with an abdominal flap from October 2006 to May 2013 were retrospectively reviewed. The patients' age and body mass index were analyzed, and a correlation analysis was performed between the weight of the mastectomy specimen and that of the initial abdominal flap. Results The average weights of the mastectomy specimen and initial abdominal flap were 451.03 g and 644.95 g, respectively. The ratio of the weight of the mastectomy specimen to that of the initial flap was $0.71{\pm}0.23$. There was a strong positive linear relationship between the weight of the mastectomy specimen and that of the initial flap (Pearson correlation coefficient, 0.728). Thirty nulliparous patients had a final-to-initial flap weight ratio of $0.66{\pm}0.11$. The 25 patients who underwent a contralateral procedure had a ratio of $0.96{\pm}0.30$. The adjusted ratio of the final flap weight to the initial flap weight was $0.66{\pm}0.12$. Conclusions Breast weight had a strong positive relationship with abdominal flap weight in Koreans. Abdominal flaps provided sufficient soft tissue for breast reconstruction in most Korean patients, including nulliparous patients. However, when the mastectomy weight is estimated to be >700 g, a contralateral reduction procedure may be considered.

• Archives of Plastic Surgery
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• 제39권1호
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• pp.46-50
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• 2012

Background : The purpose of our study was to analyze scientific papers published by South Korean plastic surgeons in journals included in the Science Citation Index Expanded (SCIE), and to evaluate the publication and research activities of Korean plastic surgeon. Methods : We conducted a survey of SCIE papers in the field of plastic surgery published by South Korean authors between 2001 and 2010 using Web of Science software. We further analyzed these results according to the number of publications per year, journals, institution, and type of papers. We also compared the total number of citations to published scientific papers. We analyzed the rank of South Korea among other countries in representative journals. Results : Overall, 667 papers were published by South Korean authors between 2001 and 2010. The number of publications increased dramatically from 2003 (n=31) to 2010 (n=139). Subsequently, the ten most productive Korean medical colleges were identified. All published papers received 2,311 citations and the citation to paper ratio was 3.49. The rank of Korea among other countries in terms of the number of published papers remained in the top 10 during the recent 10 years. Conclusions : Publication output of Korean plastic surgeon over the last 10 years showed a remarkable growth in terms of quantity and quality. Currently, Korea is among the top six countries in representative plastic surgery journals. Korean plastic surgeons have played a central role in this progress, and it is anticipated that they will continue to do so in the future.

• 한국안광학회지
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• 제9권2호
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• pp.313-322
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• 2004

유리에는 크게 무기유리와 유기유리로 크게 나눈다. 보통 무기유리를 단순히 유리라 부르고 유기유리는 합성수지 또는 플라스틱이라 부른다. 광학용 플라스틱이라고 불리는 안경용 플라스틱 인 유기렌즈 중 polycarbonate resin이 개발되었는데 이것은 기존 플라스틱렌즈보다도 굴절률이 크고 충격에 강한 우수한 특성을 가지고 있으며 오늘날 널리 이용되고 있는 플라스틱렌즈 소재이다. 본 논문은 polycarbonate resin 안경렌즈 소재에 대해서 자세히 고찰하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.639-644
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• 2000

Prestressing steels are susceptible to corrosion, which is considered the major reason in the deterioration of prestressed concrete structures. To solve this problem, many research have been made to utilize new type of tendons. FRP tendons have many advantages compared to steel tendons. However, FRP tendons have some disadvantages, such as no plastic behavior. This study focused on the flexural behavior of prestresssed concrete beams which is fabricated by post-tensioning method with CFRP (Carbon Fiber Reinforced Plastic) tendons. Th results drawn from the study, prestressed concrete beams with CFRP tendons have higher flexural cracking load, flexural yielding load, and flexural fracture load. While displacement at the fracture stage is lower compared to prestressed concrete beams with steel tendon. Excessive steel reinforcement lead lower ductility index. So, appropriate reinforcement guideline is needed. Further more, prestressed concrete beams with CFRP tendons can have sufficient ductility index when ruptured by crushing of concrete or used unbonded tendon. Therefore, the best design method for prestressed concrete beams with CFRP tendons is over-reinforcement, and use of unbonded tendon.

• 한국강구조학회 논문집
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• 제15권4호통권65호
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• pp.369-378
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• 2003

본 연구에서는 강부재에서의 손상지수를 제시하여 반복하중재하를 받는 각형강관 기둥의 파괴에 이르는 과정을 손상지수를 이용하여 규명하였다. 이를 위해 유한요소 프로그램을 이용하여 비선형 해석을 수행하였고 이에 대한 손상과정을 비교 분석하였다. 재료시험을 실시하여 재료물성치와 강종별 변형률특성을 구하였으며 이를 바탕으로 강종과 하중재하조건의 변수를 주어 이 인자들이 부재의 손상에 미치는 영향을 비교하였다. 각 변수에 따른 변형률 특성과 누적소성변형률 이력곡선을 바탕으로 하는 하중조건과 강종이 손상에 미치는 영향을 정량적으로 파악할 수 있었다.

• 한국산학기술학회논문지
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• 제12권12호
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• pp.5957-5962
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• 2011

본 연구에서는, 시화지구 북동지역 지반에 대하여 네 가지 종류의 콘계수 값들($N_{kt}$, $N_{ke}$, $N_{{\Delta}u}$, 최근 제안된 $N_e$)과 지반의 특성치들과의 관계를 고찰하였다. 다양한 실험결과를 활용하여 계산한 비배수강도와 실제 측정된 비배수강도를 비교하였으며, 이들 값들과 소성지수와의 관계를 분석하였다. $N_{{\Delta}u}$를 활용하여 구한 비배수강도는 의외로 좋은 결과를 보여주지 못했으며, 소성지수 값이 커질수록 콘계수 값이 커지는 현상이 고찰되었다.

• Journal of Welding and Joining
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• 제26권1호
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• pp.56-62
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• 2008

In this paper, elastic and plastic adhesion index was very important in deciding adhesive characteristics and varying elastic and plastic index, dimensionless load and pull-off force were analyzed and simulated. Finally, using AFM, experimental surface roughness parameters of substrates and pull-off force between tip and substrates were produced. Using these values, pull-off forces were calculated and were compared with experimental pull-off forces. Through simulation and experiment, it was found that interaction of asperity also had very important influence on adhesive contact.

• 한국결정성장학회지
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• 제4권1호
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• pp.71-75
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• 1994

본 연구에서는 (100) 배향된 단결정 실리콘 웨이퍼의 열탄성응력지수, 열응력과 임계소성변형 온도와의 관계를 모사하였다. 열탄성웅력지수는 <110> 방향에서 최대값을, <100> 방향에서 최소값을 보여주었다. 그리고, 열탄성응력지수로 부터 유도된 열응력과 임계 소성변형 온도의 모사로 부터, 실리콘 웨이퍼가 1000K 이상에서 소성변형될 수 있음을 예측할 수 있었다.

• 소성∙가공
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• 제20권7호
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• pp.498-503
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• 2011

The strain rate sensitivity index, m, plays an important role in plastic deformation at elevated temperatures. It is affected by strain rate, temperature, and the microstructure of the material. The strain rate sensitivity index has been used as a constant in numerical analysis of plastic forming at a specified strain rate and temperature. However, the value of m varies as deformation proceeds at an elevated temperature and a certain strain rate. Thus, in this present study, the value of m has been characterized as a function of strain by multiple tensile jump tests for AZ31 magnesium alloy sheet, and the variation of m has been discussed in conjunction with the microstructural observations before and after deformation. The experimental results show that the variation of m is dependent on the temperature and strain rate. Grain growth with dynamic recrystallization also affects the variation of m.