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매입형 합성보의 전단철근 및 스터드 산정방식에 대한 연구
임균택 ( Gyun-taek Lim ),홍원기 ( Won-kee Hong ),박선치 ( Seon-chee Park ),정수영 ( Su-young Jeong ) 한국구조물진단유지관리공학회 2011 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.15 No.2
The encased composite beam suggested in this paper consists of precast concrete, structural tees and cast-in-place concrete. To unify the behaviors of composite members, shear connectors were installed in the web and the flange of structural tees member respectively. There are no clear criteria available yet for estimation of shear connector quantity to be used in enclosed composite beam. To prevent construction costs from increasing for excessive design of shear connector and ensure rigidity of cross-section by unifying member behaviors, appropriate design for shear connector of encased composite beam is required. Therefore, this paper adopted the concept of shear flow and proposed design formula for dowel bar and stud in reference to required shear force.
포스포릴콜린 소재가 첨가된 컨벤셔널 콘택트렌즈의 위험관리 측면에서의 생물학적 안전성 평가
조승권(Seung-Kwon Cho),박지훈(Ji-Hoon Park),임균택(Gyun-Tack Lim) 한국안광학회 2018 한국안광학회지 Vol.23 No.1
Purpose: The aim of this study is to evaluate the degree of cytotoxic response in terms of risk management by conducting in vitro cytotoxicity test as a part of securing the biological safety of soft contact lens containing phosphorylcholine (PC). Methods: A hydrogel-type soft contact lens was prepared from 2-HEMA (2-hydroxyethyl methacrylate) as a representative of the basic skeleton of soft contact lenses, and PC as a derivative of phospholipid. As part of ensuring biological safety, the packaging and sterilization process was performed to evaluate the cytotoxicity test, and the test was conducted in the state of the finished product. The cytotoxicity tests were evaluated by extraction method (direct contact), growth inhibition test and agar diffusion test method. Results: In the extraction test method, The reagent control and negative control did not show cytotoxicity (Grade 0) and the positive control showed cytotoxicity more than medium (>Grade 2). In qualitative analysis, 10% of Confluent monolayer, 10% of Growth inhibition, 10% of Cells without intracellular granulation, 10% of Rounding, 10% of Lysis and Reactivity of Slight were observed with Grade 1. The effluent of the substance may be said to have very weak reactivity to cultured cells. Cell viability was 106.8% for MTT, 100% for blank test, 2.4% for positive control, and 106.5% for negative control. No cell death or morphological changes were observed in the test group treated with the test substance after 24 hours of incubation by microscopic observation. In the agar diffusion test method, no discoloration zone was observed on the middle layer of the cells to which the test substance was administered, and no cell lysis was observed in the lower part of the specimen. Reactivity zone was not observed in the middle layer of the solvent control and negative control, and the positive control group had a reactivity zone of 0.5 cm or more as expected. Conclusions: The biological stability of hydrogel-type soft contact lenses consisting of PC and 2-HEMA was evaluated in terms of risk management in order to achieve the intended performance in the design development process. In addition, no cytotoxic substances have been eluted in the production of corneal epithelium, and no adverse effects due to irritation or immune response on the corneal surface are expected.
포스포러스 그룹 소재를 지닌 안광학 의료기기의 물리화학적 특성 연구
조승권(Seung-Kwon Cho),박지훈(Ji-Hoon Park),임균택(Gyun-Tack Lim) 한국안광학회 2018 한국안광학회지 Vol.23 No.1
Purpose: In this study, the physicochemical properties of hydrogel soft contact lenses were investigated by introducing phosphorous materials, which are known as biocompatible components to improve comfort and wettability. Methods: The homopolymer of PolyHydroxy ethyl methacrylate (PHEMA), methacrylic acid (MA) series (MA and PHEMA) known as ionic groups and copolymers of phosphorus group (PC) and PHEMA were prepared with hydrogel. The applicability of the MP samples composed of PC as the hydrogel contact lens material was evaluated by FT-IR analysis, TGA thermal stability, tensile strength, water content, oxygen Permeability, etc., and the characteristics such as contact angle and protein adsorption amount for evaluating wettability were compared and analyzed. Results: The copolymerization state of the hydrogel samples was confirmed by FT-IR analysis, and thermal decomposition was analyzed with TGA and the thermal stability was confirmed to be high. Water content was measured by hydrophilization property. When the homopolymer POL samples of PHEMA have a water content of 40% and the MA series samples copolymerized with the ionic component increases to 2.50 mol% (50.46%) and 5.00 mol% (66.68%). The MP samples of phosphorus (PC) was increased as the content of phosphorous was increased (51.41%, 61.03%, 70.84%). The Oxygen permeability (Dk) of the POL samples was 8.22 (Dk × 10<SUP>−11</SUP>), and the MA and MP series samples increased in proportion to the water content. The highest oxygen permeability was measured as MP03 sample 27.80 (Dk × 10<SUP>−11</SUP>). In order to evaluate the durability of hydrogel contact lenses, specimens were prepared by the films. The MP series samples with high water content were measured very low (0.117 MPa, 0.086 MPa, 0.041 MPa). In this study, The contact angle and the degree of protein adsorption were measured to evaluate the wettability indirectly. Generally, in the samples containing ionic group and phosphorus component, the contact angle was measured lower than that of the POL samples, and the hydrophilic property was stronger and the wetting property was confirmed to be high. In the measurement of the protein adsorption amount of each sample, it was confirmed that the MP series samples containing the phosphorus materials had a decrease in protein adsorption amount as a whole. Conclusions: When the characteristics of PC material derived from this study are compared with each other by physicochemical analysis, it is considered that it can be applied as an ophthalmic medical device sufficiently. In order to secure more stability after production as a finished product, Biological Evaluation can be added.