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노즐 이송 방식 딥코팅 시스템을 활용한 장형 다공성 인조혈관 제작
이승문(Seung-Mun Lee),김영서(Yeong-Seo Kim),박석희(Suk-Hee Park) 한국기계가공학회 2023 한국기계가공학회지 Vol.22 No.7
Dip-coating methods, in conjunction with 3D printing and particle leaching, provide a promising approach for fabricating artificial vascular grafts with enhanced mechanical and biocompatible properties through the incorporation of porous structures. However, the current limitations of the dip-coating process hinder the fabrication of long vascular grafts suitable for femoral artery treatment. These limitations include the requirement of a solution tank deeper than the length of template and an excessive amount of coating solution. Moreover, the extended exposure time of the pre-formed porous structure to the coating solution during the multi-coating process often leads to significant damage. To address these challenges, we developed a novel coating system that utilized a moving nozzle containing coating solution, thereby significantly reducing the amount of solution required. Furthermore, the developed system minimized the exposure time of the porous structure to the coating solution. We employed the appropriately sized nozzle to prevent the leakage of coating solution through the gap between the template and the nozzle during the process. Additionally, we determined the optimal nozzle transfer rate to achieve uniform coating thickness. Consequently, this approach enabled the fabrication of long porous artificial vascular grafts, specifically exceeding 30cm in length, with internal porous structures that potentially improved biocompatibility while maintaining coating uniformity.
하악 구치부에서 ITI SLA (Sand-blasted, Large-grit, Acid-etched) 임플란트를 이용한 단일 치아 수복의 후향적 임상 연구
이승문,채경준,정의원,김창성,최성호,조규성,김종관,채중규,Lee, Seung-Mun,Chae, Gyung-Joon,Jung, Ui-Won,Kim, Chang-Sung,Choi, Seong-Ho,Cho, Kyoo-Sung,Kim, Chong-Kwan,Chai, Jung-Kyu 대한치주과학회 2006 Journal of Periodontal & Implant Science Vol.36 No.3
The purpose of this study was to evaluate cumulative survival rate (CSR, %) of mandibular posterior single tooth implants replaced with ITI SLA (sand-blasted, large-grit, acid-etched) implant system and compare the CSR between first and second molar. The findings from the results were as follows; 1. Total of 158 implants were inserted into 147 patients. 68 patients were males, 79 patients were females and their mean age was 47.8 years. 98 implants were placed in first molar area and 60 implants were placed in second molar area. In terms of diameter, implants with wide diameter over 4.8mm dominated (91.1%). Implants with length over lOmm were used (96.2%). 2, In the two cases, there was a slight transient numbness which recovered within 1-2 months. Nine SynOcta screw type abutments demonstrated screw loosening, There were ten cases of crown fallen-out from decementation. 3. Only one failed out of 158 implants. The CSR was 99.4%. The CSRs for first molar and second molar were 99% and 100%, respectively. From the results, it was concluded that single tooth replacement implant in the mandibular posterior area, might be considered as the effective treatment modality comparable to the conventional crown and bridge.
이승정,윤영철,조우연,유성문,지광습,Lee, Seung-Jung,Yoon, Young-Cheol,Cho, Woo-Yeon,Yu, Seong-Mun,Zi,, Goang-Seup 한국전산구조공학회 2009 한국전산구조공학회논문집 Vol.22 No.4
본 논문에서는 비선형 유한요소해석 기법을 이용하여 API-X80 강재 라인파이프의 대변형 비선형 거동을 모사하였다. 강재의 구성방정식을 작성하기 위해 GTN(Gurson-Tvergaard-Needleman) 모델을 사용하였다. 대변형 해석을 위해 범용 유한요소해석 프로그램인 ABAQUS과 연계해서 사용할 수 있는 사용자 서브루틴(User Subroutine)의 사용자 재료모델(UMAT)을 개발하였다. 유한요소해석 결과와 일축인장실험의 결과와의 비교를 통해 GTN 모델에서 사용되는 재료모델상수를 도출하였다. 도출된 모델상수를 이용해 API-X80 강재 라인파이프의 소성 좌굴변형해석을 실시하여 실험결과와 비교하였고 소성 좌굴변형에서 발생하는 거동 특성을 성공적으로 모사하였다. We simulated large deformation and inelastic behavior of API-X80 steel linepipes using nonlinear finite element method. Gurson-Tvergaard-Needleman(GTN) model is employed for the development of the constitutive model of the steel. The GTN model is implemented in the form of the user-supplied material subroutine(UMAT) for the commercial software of ABAQUS. To calibrate the model parameters, we simulated the behavior of the uniaxial tension test using ABAQUS equipped with the developed GTN model. Using the set of the model parameters, we were able to capture the characteristics of the plastic buckling of API-X80 steel linepipes.
이승범 ( Lee Seung Beom ),이승문 ( Lee Seung Mun ),홍인권 ( Hong In Gwon ) 한국공업화학회 2003 공업화학 Vol.14 No.7
유지종의 추출공정에는 여러 가지 용매추출법이 사용되고 있다. 본 연구에서는 초음파 에너지가 도입된 추출공정과 증류나 용매추출을 이용한 공정의 최적 추출조건에서 추출특성과 초음파 에너지 밀도 영향에 따른 추출특성을 분석하였다. 초음파의 조사시간은 1, 3, 5, 10, 20, 30 min이고, 추출공정에서 온도변수로 293.15, 303.15, 313.15 K가 적용되었으며, 초음파의 세기는 390 W부터 520 W로 65 W의 간격으로 변화를 주었다. 또, 초음파 세기에 따른 초음파 에너지 밀도는 측정하였으며, 온도와 시간에 따른 초음파 에너지 영향에 대해서도 해석하였다. 초음파의 조사시간과 초음파 세기 증가에 따라 유지의 추출량도 증가하는 경향을 보였으며, 유지 추출공정을 도입하므로써 단순 용매추출공정에 비해 추출조작시간이 크게 단축 되었다. 초음파의 세기가 증가됨에 따라 초음파 에너지 밀도는 증가하는 경향을 나타내었으며, 온도증가에 따라 초음파 에너지 밀도는 감소하는 경향을 보였다. Most of the oils were extracted through distillation and solvent extraction processes. In this study, the characteristics of oil extraction process from rice bran were evaluated in an optimum operating condition by comparing the ultrasound assisted solvent extraction(UASE) process to the distillation and the solvent extraction processes. And UASE process was studied in terms of the ultrasonic energy density effects and the extraction yield. Then, the ultrasonic irradiation time was varied as 1,3,5,10,20 and 30 min and the extraction temperature was set at 293.15, 303.15, and 313.15 K. The ultrasonic power was varied in the range of 390 to 520 W. The energy density was evaluated in terms of the ultrasonic intensity, the ultrasonic irradation effects with the temperature and irradiation time were analyzed. The extraction amount of rice bran oil was increased with ultrasonic irradiation time and ultrasonic power. The irradiation time ultrasonic extraction process was very shorter than the previous extraction processes. The ultrasonic energy density was proportional to the irradiation power, but the energy density was inversely proportional to the operating temperature.