소수성 모노머들을 포함한 콘택트렌즈의 특성에 관한 연구

예기훈,김태훈,성아영 한국안광학회 2008 한국안광학회지 Vol.13 No.3

목적: 본 연구에서는 HEMA(2-Hydroxyethyl methacrylate)/Silicone 기본 조합에 각각 BMA(Butyl methacrylate)와 MMA(Methyl methacrylate)를 혼합하여 콘택트렌즈의 재료로 사용한 후, 각각의 물리적 특성을 비교하였다. 방법: 캐스트 몰드 법을 이용하여 각각의 렌즈를 제조 하였으며, 각 시료의 물리적 특성에 대한 평균값을 사용하여 분석 하였다. 결과: HEMA/silicone/BMA 조합의 경우, 함수율은 24.69%에서 29.26%, 인장강도는 0.109kgf에서 0.263kgf 의 분포를 나타내었다. HEMA/silicone/MMA 조합의 경우, 팽윤율은 13.56%에서 14.83%, 함수율은 25.61%에서 29.33%, 인장강도는 0.107kgf에서 0.286kgf의 분포를 나타내었다. 결론: 두 조합은 HEMA/silicone(0.20%~11.50%) 의 기본 조합에서 BMA(5.15%)와 MMA(5.15%)를 일정량 첨가한 것으로 두 경우 모두에서 BMA의 양과 MMA의 양이 상대적으로 감소할수록 팽윤율과 함수율이 증가하는 경향을 보였다. HEMA/silicone/MMA 조합의 경우, 인장 강도는 silicone의 비율이 증가할수록 4-MMA 시료까지는 다소 증가하는 경향을, HEMA/silicone/BMA 조합의 경우 , 인장강도는 silicone의 비율이 증가할수록 감소하는 경향을 나타내었다. Purpose: In this study, we compared the physical properties of the compositions that were mixed with basic materials of HEMA (2-Hydroxyethyl methacrylate)/Silicone and BMA (Butyl methacrylate), MMA (Methyl methacrylate) by making the silicone contact lens. Method: Each sample of contact lenses was fabricated by cast mould method. We analyzed results by using average values of physical property of each sample. Results: In the composition of HEMA/Silicone/BMA, water contents of samples showed the value from 24.69% to 29.26%. Ultimate strength of samples showed the value from 0.109 kgf to 0.263 kgf. In the composition of HEMA/ Silicone/MMA, swelling ratio of samples showed the value from 13.56% to 14.83%. Water contents of samples showed the value from 25.61% to 29.33%. Ultimate strength of samples showed the value from 0.107 kgf to 0.286 kgf. Conclusions: The compositions of percents of silicone were ranged from 0.20% to 11.50% and the composition percent of BMA and MMA was 5.15% in total. Swelling ratio and water contents increased with decreasing of BMA (Butyl methacrylate) and MMA (Methyl methacrylate) percent. In the composition of HEMA/Silicone/MMA, the values of ultimate strength increased with increasing of silicone percent to 4-MMA sample. In the composition of HEMA/Silicone/BMA, the values of ultimate strength decreased with increasing of silicone percent.

BMA를 포함한 실리콘 중합체의 특성에 관한 연구

예기훈,김태훈,성아영 대한시과학회 2007 대한시과학회지 Vol.9 No.4

본 연구는 소프트 콘택트렌즈의 주된 재료인 HEMA(2-hydroxyethyl metacrylate)와 유연성을 갖게 하는 BMA(butyl methacrylate), 친수성의 acrylate를 포함한 silicone polyether acrylate등을 사용하여 콘택트렌즈 재료를 중합하였다. 사용된 각각의 단위체들을 다른 비율로 조합하여 열중합하였으며, 제조된 콘택트렌즈 sample은 하루 동안 수화시킨 후 팽윤율 (swelling ratio) 및 함수율(water content), 광투과율(optical transmittance) 과 인장강도(ultimate strength) 등의 평균값을 비교 분석하였다. HEMA 중합의 경우 팽윤율과 함수율은 각각 20.09%와 29.99%로 나타났으며, 광투과율은 90.60%, 인장강도 0.145 kgf로 나타났다. HEMA/Silicone(0.2%~11.5%) 중합에서는 silicone의 비율이 증가할수록 함수율과 팽윤율이 증가하는 경향을 나타내었으며 인장강도는 감소하는 경향을 나타내었다. BMA를 일정하게 첨가한 HEMA/Silicone(0.2%~11.5%)/ BMA 중합에서는 BMA의 양이 감소함에 따라 함수율과 팽윤율이 상대적으로 증가하는 경향을 나타내었다. 인장강도 또한 점차적으로 감소하는 경향을 나타내었다. In this study, we polymerized contact lens materials using monomers HEMA (2-hydroxyethyl methacrylate) which is known as a main material of soft contact lens, BMA(butyl methacrylate) for flexibility, MMA(methyl methacrylate) for stability, the silicone polyether acrylate with acrylate for hydrophilic material. We prepared monomers with different composition percents for our experiment. Contact lens were fabricated by thermal polymerization. And then samples were hydrated for one day. We showed results by using average value of physical property of each sample and analyzed swelling ratio, water content, optical transmittance and ultimate strength of contact lenses which were fabricated. In the composition of HEMA, swelling ratio and water contents of samples showed each 20.09% and 29.99%. Optical transmittance and ultimate strength of samples showed each 90.60% and 0.145 kgf. In the composition of HEMA/Silicone(0.2%~11.5%), swelling ratio and water content of values increased with increase of silicone percent. A ultimate strength values decreased gradually. In the composition of HEMA/Silicone/BMA, the composition percents of silicone were ranged from 0.2% to 11.5% and the composition percent of BMA(butyl methacrylate) was 5.15%. Swelling ratio and water contents increased with decrease of BMA(butyl methacrylate) percent. Also, ultimate strength values decreased gradually.

지역 디지털 콘텐츠산업의 활성화 방안에 관한 연구 : 충북지역 디지털 콘텐츠산업을 중심으로

안종묵 청주대학교사회과학연구소 2006 한국사회과학연구 Vol.28 No.1

본 연구에서는 충북 지역의 디지털 콘텐츠산업의 활성화 방안을 고찰하였다. 집적 단지 형성을 통한 디지털 콘텐츠산업 활성화 방안은 크게 산-학-관의 원활한 네트워킹과 이들의 자기 혁신을 들 수 있다. 종래 산업사회에서 지역 집적은 동일 업종간의 상호 네트워크가 중요하였으나, 디지털 콘텐츠산업과 같은 문화산업 집적단지는 동일 업종이 아닌 멀티미디어, 기술 개발, 창작, 마케팅 등 연관 산업 분야 및 관련 인력 간의 긴밀한 네트워크가 가능한 곳이어야 한다. 또한 집적단지 안에서 정부 조직과 민간 조직이 원활한 네트워킹이 가능할 때, 집적단지 성공은 가능할 것이다. 그리고 집적단지 산업으로 디지털 콘텐츠 산업의 발전을 위해 논의할 수 있는 것은 산-학 연계이다. 이를 위해선 대학과 기업 간에 긴밀한 네트워크가 중요하다. 충북 지역에도 콘텐츠관련 업계와 지역 대학과의 연계가 절실히 필요하며, 가능하면 집적단지 안에 관련학과를 이전함으로써 더욱 긴밀한 산-학 연계가 이루어져야 한다. 기존 산업구조에서 새로운 첨단산업인 디지털 콘텐츠산업으로 전환하는데 혁신성이 요구된다. 충북 지역에도 디지털 콘텐츠산업의 활성화를 위해선 지역 정부와 지역 기업의 혁신이 더욱 요구된다. 특히 이 과정에서 행정 당국의 역할이 중요하다. 실리콘앨리와 CIQ가 성공할 수 있었던 요인 중에 하나는 행정 당국의 유인책이었다. 시 당국은 벤처기업들에게 재산세와 양도소득세를 감면해 주었으며, 창업 자금과 임대료를 지원해 주었다. 충북 지방정부 역시 좀 더 입주업체들이 피부로 느낄 수 있는 지원을 통해 유인책을 줄 필요가 있다. This study analysed the growth scheme to the local firms of digital contents, in particular, Chungchongbuk-do's firms of digital contents. According to Network of firm-academy-government and their Innovation, the growth to the local firms of digital contents through industrial complex are able to materialize. The local industrial complex of the traditional industries value networks among same category of businesses, however, the local industrial complex of the digital contents are interested in the different type of business (i. e. multimedia, development technology, creative, marketing). In addition, the growth to the local firms of digital contents need to network between government and firms in the local industrial complex. And we also need to discuss the network of firm-academy for the purpose of the growth to the local firms. The local firms and universities regrading to digital contents need to keep in close networking in Chungchongbuk-do, if possible, the related department of university need to move into industrial complex. On the other way, the traditional industry transform the ultramodern industry in relation to digital contents need to request Innovation. The growth to the local firms of digital contents in Chungchongbuk-do is closely related to innovation of the local government and firms. In particular, the most important on its process is the role of the government. One of the growth issues is the enticement of government in Silicon Alley and CIQ. Its governments reduced tax on property and income tax to venture firms regrading to digital contents, and also supported origination expense and property rental. We need to discuss about the enticement of Chungchongbuk-do for the purpose of the growth to the local firms of digital contents.

Silicon biostimulant enhances the growth characteristics and fortifies the bioactive compounds in common and Tartary buckwheat plant

Md Obyedul Kalam Azad,박범선,Md. Adnan,Mateja Germ,Ivan Kreft,우선희,박철호 한국작물학회 2021 Journal of crop science and biotechnology Vol.24 No.1

Silicon is a potential biostimulant that has been used to enhance the yield and quality of plant products. Therefore, we aimed to evaluate the eff ect of soluble silicon on the growth characteristics and bioactive compounds content of common and Tartary buckwheat. The silicon was applied with three different doses such as low, medium, and high three times after 3 weeks of buckwheat sowing at 10 days interval. The control was done without the application of silicon. It is observed that silicon has a significant influence on having identical inclination on growth and bioactive compounds accumulation in both buckwheat cultivars. Our study showed an interesting result that lower doses of silicon enhance the growth characteristics, total and single phenolic substances (syringic acid, 4 hydroxy benzoic acid, ferulic acid), total flavonoids, rutin, quercetin content, and antioxidant capacity in common buckwheat, on the other hand, higher doses of silicon favor for Tartary buckwheat. Moreover, further investigation is needed to evaluate the optimal dose and mode of action of silicon for the enhancement of growth and phytochemical content in buckwheat plants.

실리콘의 종류에 대한 콘택트렌즈 함수율의 변화에 관한 연구

예기훈,김태훈,성아영 대한시과학회 2008 대한시과학회지 Vol.10 No.1

함수율은 친수성 하이드로젤 콘택트렌즈의 가장 중요한 물리적 특성 중의 하나이다. 또한 함수율은 콘택트렌즈의 유연성과 내구성 그리고 산소투과성과 착용감 등에 영향을 주는 중요한 요인이다. 목적: 따라서 본 연구는 소프트 콘택트렌즈에 사용되는 기본적인 재질과 실리콘을 사용하여 중합한 후, 각각의 조합에 대한 함수율을 비교 분석하기 위해 두 가지의 다른 실리콘을 사용하여 콘택트렌즈를 제조하였다. 방법: 캐스트몰드 법을 이용하여 각각의 렌즈를 제조하였으며, 각 sample의 물리적 특성에 대한 평균값을 사용하여 분석하였다. 결과: 9.00%의 실리콘을 포함한 sample의 함수율은 각각 55.27%와 64.58%를 나타내었으며, 같은 조합에 1.00% 의 EGDMA를 첨가하였을 때 함수율은 감소하였다. 결론: 실리콘의 함량이 감소할수록 함수율이 증가하는 경향을 보였다. Water content is one of the important physical properties in the hydrophilic hydrogel contact lens. Also, water content is a primary factor which influence on the flexibility, the durability, the oxygen transmissibility and the eye comfort. In this study, we polymerized contact lens materials using basic monomers which is known as the main materials of soft contact lens and silicone. Purpose: And also, we made the contact lens using two types of silicone to analysis the water contents of each composition. Methods: Each sample of contact lenses was fabricated by Cast mould method. We analyzed results by using average value of physical property of each sample. Results: In the composition of silicone(9.00%), water content of sample showed 55.27% and 64.58% each. In case of the composition including EGDMA(1.00%), water content of sample decreased. Conclusion: Water content increased with decrease of silicone percent.

다양한 SiC 섬유를 적용한 실리콘 용융 침투 공정 SiC_f/SiC 복합재료의 제조 및 특성 변화 연구

송종섭 ( Jong Seob Song ),김세영 ( Seyoung Kim ),백경호 ( Kyeong Ho Baik ),우상국 ( Sangkuk Woo ),김수현 ( Soo-hyun Kim ) 한국복합재료학회 2017 Composites research Vol.30 No.2

섬유강화 세라믹 복합재료 제조 방법 중 실리콘 용융 침투 공정법(Liquid Silicon Infiltration-LSI)은 낮은 제조단가 및 짧은 공정 시간 등의 장점을 가진다. 본 연구에서는 고온 내산 특성이 우수한 SiC 섬유를 LSI 공정에 적용하기 위해 결정화도와 산소함량이 다른 세 가지 SiC 섬유(Tyranno SA, LoxM, Tyranno S)를 이용하여 SiC_f/SiC 복합재료를 제작하고 그 적용 가능성을 확인하였다. LSI 공정을 통해 제조된 SiC_f/SiC 복합재료는 모두 2% 미만의 기공률로 치밀화 되었지만, 섬유의 결정화도와 산소함량에 따라 3점 굽힘강도는 큰 차이를 나타냈다. 이는 1450oC이상의 높은 LSI 공정 온도에 SiC 섬유가 노출 될 경우 비정질 SiOC상이 결정화되며 수축하는 현상과 섬유 내 잔존 산소-모재 내 탄소의 반응으로 인한 미세구조 차이에 기인하는 것으로 판단된다. 이는 SEM, XRD 및 TEM 분석을 통해 섬유 종류별 공정온도에서의 특성 변화로 확인하였다. Liquid silicon infiltration, which is one of the methods of producing fiber reinforced ceramic composites, has several advantages such as low fabrication cost and good shape formability. In order to confirm LSI process feasibility of SiC fiber, SiC_f/SiC composites were fabricated using three types of SiC fibers (Tyranno SA, LoxM, Tyranno S) which have different crystallinity and oxygen content. Composites that were fabricated with LSI process were well densified by less than 2% of porosity, but showed an obvious difference in 3-point bending strength according to crystallinity and oxygen content. When composites in LSI process was exposed to a high temperature, crystallization and micro structural changes were occurred in amorphous SiOC phase in SiC fiber. Fiber shrinkage also observed during LSI process that caused from reaction in fiber and between fiber and matrix. These were confirmed with changes of process temperature by SEM, XRD and TEM analysis.

Optimization of Zinc Coating Thickness by Unreplicated Factorial Design of Experiments in Hot‑Dip Galvanization Process

Neha Verma,Vinay Sharma,M. Affan Badar,Niharika Choubey,Rityuj Singh Parihar 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.10

Over-coating of the zinc layer in the hot-dip galvanization process is a common issue. The coating thickness of zinc depends on various factors such as zinc bath temperature, dipping time, silicon percentage in steel, alloy composition in zinc bath, etc. In the current work, three factors: dipping time, silicon percentage in steel, and nickel percentage in zinc bath have been considered in an unreplicated 23 factorial design using secondary data from Bondareva (Materials Science Forum 992:689–694, 2020). Lenth’s method and normal probability plot are utilized to analyze the factorial design. It is identified that dipping time and nickel percentage are the two significant factors impacting the coating thickness. At 0.05% of nickel and 3 min of dipping time, minimum coating thickness is achieved, i.e., the thickness reduces up to 38.96% and 29.57% for 0.18% and 0.28% silicon-containing steels, respectively as compared to no nickel present in the zinc bath at 5 min of dipping time. All the experiments correspond to a bath temperature of 450 °C and phosphorus content of 2.5% in steels. The result is beneficial for industry to achieve better product quality and gain competitive advantage.

Comparison of Physical Properties of Domestic Contact Lenses - Focusing on oxygen transmissibility -

Ki-Sung Kim 한국융합학회 2018 한국융합학회논문지 Vol.9 No.1

산소전달률이 높은 것으로 알려진 실리콘 하이드로젤 콘택트렌즈의 사용이 증가하고 있지만 함수율과 산소전달률 등 물리적 특성이 표시되지 않은채 판매되고 있다.본 연구에서는 국내에서 허가된 실리콘 하이드로젤 콘택트렌즈의 함수율과 산소전달률 등의 물리적 특성을 분석하기 위하여, 식품의약품안전처 웹사이트에 공개된 허가정보를 수집 분석하였다. 본 연구에서 분석된 국산 실리콘 하이드로젤 콘택트렌즈 68건 가운데 61건(89.7%)이 산소투과성에 관한 국제규격을 만족하지 못하였다. 실리콘 하393이드로젤 콘택트렌즈에 대한 국내규격이 부재하여 하이드로젤 콘택트렌즈와 차이가 없는 제품도 실리콘 하이드로젤 콘택트렌즈로 신고되었기 때문으로 판단된다. 앞으로 신고된 정보 뿐만 아니라 유통되고 있는 실리콘 하이드로젤 콘택트렌즈의 물리적 특성에 대한 분석이 요구된다. Although the use of silicone hydrogel contact lenses which are known to have high oxygen transmissibility is increasing, they are being sold without any product labeling of physical properties such as water content and oxygen transmissibility. To analyze the physical properties such as the water content and oxygen transmissibility of approved silicone hydrogel contact lenses, this study collected and analyzed the approval information published on the KFDA website. Of 68 cases of domestic silicone hydrogel contact lenses analyzed in this study, 61 cases (89.7%) did not meet the international standard for oxygen permeability. This is because lenses that are not different from hydrogel contact lenses were submitted for approval as silicone hydrogel contact lenses because there is no domestic standard for silicone hydrogel contact lenses. In future, besides the information published on the website, analysis of the physical properties of a wide variety of actual silicone hydrogel contact lenses on the market is required.

Studies on the Effect of Silicon Nutrition on Plant Growth, Mineral Contents and Endogenous Bioactive Gibberellins of Three Rice Cultivars

Jang, Soo-Won,Hamayun, Muhammad,Sohn, Eun-Young,Shin, Dong-Hyun,Kim, Kil-Ung,Lee, In-Jung The Korean Society of Crop Science 2007 Journal of crop science and biotechnology Vol.10 No.1

Silicon is one of the key elements for healthy growth and development in rice crops. We analyzed the effect of silicon(Si) on some growth parameters, plant mineral contents, and bioactive gibberellins in three rice cultivars. Silicon was applied at the rates of 0 kg/0.1ha(control), 40 kg/0.1ha, and 80 kg/0.1ha throughout the course of experiment. Plant growth parameters were enhanced by the application of elevated Si, though plant height and culm length were more favorably affected than the respective dry weights. The plant mineral contents analyzed also increased in treatments where Si was applied without potassium, demonstrating that Si application promotes the absorption of these minerals in rice crops. The endogenous gibberellins measured in our study showed that $GA_1$ is the only bioactive GA form present in rice seedlings. The endogenous $GA_1$ and its precursor $GA_{20}$ contents increased after Si application. However, this increase in endogenous $GA_1$ and $GA_{20}$ contents, and plant growth parameters were different according to the rice cultivars. Our results indicate that Si is a beneficial element in rice nutrition and that different cultivars of Oryza sativa show differential responses to Si nutrition in terms of their growth and development.

고압절연용 실리콘고무의 전기특성 및 물성에 관한 연구

지원영,이준호 한국고무학회 2002 엘라스토머 및 콤포지트 Vol.37 No.2

고압애자용 실리콘 고무를 제조하기 위해 사용되는 polydimethylsiloxane(PDMS)의 vinyl 기 함량과 실리카의 종류가 전기특성 및 물성에 미치는 영향을 연구하였다. 실리콘 폴리머의 비닐함량이 증가함에 따라 가교밀도와 경도가 높아졌으며 이로 인해 인장강도, 체적저항 및 트래킹 특성이 증가하였다. 건식실리카로 보강된 실리콘 고무가 습식실리카로 보강된 실리콘 고무보다 전기적 특성 및 물성이 우수하였으며 이는 실리카에 존재하는 수분의 함량에 영향을 받는 것을 알 수 있었다. This study was carried out to investigate the influences of the vinyl content of polydimethylsiloxane(PDMS) and type of silica on the electrical and mechanical properties of silicone rubber for high voltage insulation. When the content of vinyl group was increased, cross-linking density and hardness were increased, and tensile strength, volume resistivity and tracking resistance were improved. The mechanical and electrical properties of silicone rubber reinforced with fumed silica were higher than those of silicone rubber reinforced with precipitated silica. It was found that the electrical and mechanical properties of silicone rubber were influenced greatly by the water contents of silica.