• 한국공작기계학회논문집
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• 제16권6호
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• pp.133-139
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• 2007

In this paper, optics polishing technology using adaptive tool and eccentric motion mechanism was suggested. Optics polishing can make high reflective and accurate surface. The optics polishing process based on the eccentric motion mechanism has been used to manufacture the ophthalmic lens mold. Also ophthalmic lens mold factory hold conventionally a lot of the curved polishing tools for the versatile mold curves of eye diopters and want to reduce tool numbers. Therefore, a polishing machine with adaptive airbag tool was developed and experimentally verified in view of surface roughness and form accuracy.

• 한국안광학회지
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• 제16권1호
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• pp.31-40
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• 2011

목적: 본 연구는 안경원에서의 안경용 초음파세척기를 이용한 소프트렌즈 세척 실태를 조사하고 세척용기를 달리하였을 때의 단백질 제거 효과를 비교하기 위하여 수행되었다. 방법: 서울시 소재 75개 안경원을 대상으로 소프트렌즈 세척 실태에 관한 설문조사를 실시하였다. 또한 인공누액을 사용하여 소프트렌즈에 인위적으로 단백질을 침착시킨 후 세척용기를 달리하여 안경용 초음파세척기로 세척한 후 단백질 잔존량을 측정함으로써 세척효율을 비교하였다. 또한 반복적인 초음파 세척으로 인한 소프트렌즈의 표면과 습윤성 변화를 분석하였다. 결과: 안경원에서 콘택트렌즈 세척에 안경용 초음파세척기를 이용하는 주목적은 신속함 때문임을 확인하였다. 세척용기로 플라스틱 렌즈 용기와 유리병 렌즈용기를 사용하고 안경용 초음파세척기로 소프트렌즈를 세척한 경우 유리병 렌즈용기를 사용하였을 때 세척효율이 높은 경향을 보였으나 유의성 있는 차이는 아니었다. 한편 반복적인 초음파 처리로 인하여 소프트렌즈의 표면과 습윤성의 변화가 나타남을 관찰할 수 있었다. 결론: 안경용 초음파세척기 이용 시 세척용기로 플라스틱 렌즈용기와 유리병 렌즈용기의 사용이 모두 효과적이었지만 반복적인 초음파 세척 시에는 세척용기를 사용하였다 하더라도 초음파로 인한 소프트렌즈의 변성이 우려되므로 주의를 기울여 사용하여야 것이다.

• 지역사회간호학회지
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• 제25권4호
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• pp.259-269
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• 2014

Purpose: The purpose of this study was to examine dry eye syndrome and ocular fatigue according to the status of contact lens wearing and management among female university students. Methods: The subjects were 195 female university students wearing contact lenses. Ocular Surface Disease Index (OSDI) and Virtual Reality Symptom Questionnaire (VRSQ) were used to determine the level of dry eye syndrome and ocular fatigue. The SPSS/WIN 21.0 program was used for analysis of data. Results: Significant differences in the level of dry eye syndrome were observed according to the period of case solution change (F=3.36, p=.037) and the reasons for the change of lens (F=4.56, p=.004). In ocular fatigue, significant differences were observed according to the price of lens (F=3.53, p=.031), rinse in storing lens in a case (t=-2.57, p=.011), and learning about contact lens (t=-2.01, p=.046). A significant positive correlation was observed between dry eye syndrome and ocular fatigue in the subjects. Conclusion: The results of this study show that some subjects have problems in wearing and management of contact lenses. Therefore, an education program related to contact lenses should be provided to contact lens wearers to improve the status of wearing and management of contact lenses.

• 한국기계가공학회지
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• 제15권5호
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• pp.109-116
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• 2016

Polymethyl methacrylate is commonly used in the outer lens of automotive rear lamps. However, if the lens warps above the allowable limit, it may lead to faulty connection with the housing, and failure of the assembly. This study investigated the effects of gate diameter and cooling line distance in the mold design for automotive outer lens. The optimal gate diameter and cooling line distance to minimize the warp of the outer lens were derived as 3.0 mm and 50-60 mm respectively, and the cooling temperature to minimize warp was shown to be $60-80^{\circ}C$ (mold surface temperature $48-67^{\circ}C$). A higher cooling temperature may somewhat mitigate the warp, but is undesirable because it may cause injection molding problems, such as sinks. A mold was constructed matching the optimal design and the produced lens properties, particularly the degree of warp, were comparable with the CAE predictions.

• 한국정밀공학회지
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• 제22권6호
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• pp.55-60
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• 2005

This paper has been focused in developing of plastic lens with ultra-precision and low birefringence ability using by injection molding simulation tools. The simulation tools, $3D-Timon^{TM}\;and\;Asu-Mold^{TM}$ were applied to visualize indirectly the flow pattern of melted polymer enter the mould and the simulation results are verified as compared with the experimental results. Birefringence and polarized light generated in injection molding process was also calculated for each injection conditions and compared with .the pictures of experimented optical lens go through the polarized light plates device. A spherical radius of plastic optical lens transcribed from profile of mould core surface was measured to estimate the geometrical accuracy fer the each injection conditions. It is confirmed that the simulation results about flow pattern and polarized light area coincided in experimental results. It is known that increasing in thickness shrinkage at center of lens, the spherical radius is larger from comparing the graph measured spherical radius and the thickness shrinkage at center of lens

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.145-145
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• 2019

Groundwater and rainwater are the only sources of freshwater in small islands as many islands lack surface water sources. Groundwater occurring in the form of freshwater lens floating on denser seawater is highly dependent on natural recharge from rainfall. A sharp interface numerical model for regional and well scale modeling is selected to assess the sustainability of freshwater lens in the island of Tongatapu. In this study, 29 downscaled General Circulation Model(GCM) predictions are input to the recharge model based on water balance modelling. Three GCM predictions which represent wet, dry and medium conditions are selected for use in the groundwater flow model. Total freshwater volume and number of saltwater intruded wells are simulated under various climate scenarios with GCM predicted rainfall pattern, sea level rise and pumping. Simulations indicate that the sustainability of the freshwater lens is threatened by the frequent droughts which are predicted under all scenarios of recharge. The natural depletion of the lens during droughts and increase in water demands, leads to saltwater upconing under the pumping wells. Implementation of drought management measures is of utmost importance to ensure sustainability of freshwater lens in future.

• Journal of the Optical Society of Korea
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• 제14권2호
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• pp.163-169
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• 2010

Novel wafer-level fabrication of a glass ball-lens is realized for optoelectronic applications. A Pyrex wafer is bonded to a silicon wafer and cross-cut into a square-tile pattern, followed by wet-etching of the underlying silicon. Cubes of Pyrex on the undercut silicon are then turned into ball shapes by thermal reflow, and separated from the wafer by further etching of the silicon support. Radial variation and surface roughness are measured to be less than ${\pm}3\;{\mu}m$ and ${\pm}1\;nm$, respectively, for ball diameter of about $500\;{\mu}m$. A surface defect on the ball that is due to the silicon support is shown to be healed by using a silicon-optical-bench. Optical power-relay of the ball lens showed the maximum efficiency of 65% between two single-mode fibers on the silicon-optical-bench.

• 소성∙가공
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• 제14권3호
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• pp.245-250
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• 2005

Recently, micro machining technology for high precision mold becomes more interested for mass production of high performance optical parts micro-grooved on the surface, which is under very active development due to its effectiveness in the view point of optical performance. Mechanical micro machining technology now has more competitiveness on lithography, MEMS or LIGA processes which have some problems to fabricate especially cylinder type of groove in such as lenticular lens for illumination angle modulation system. In this study. a lenticular lens mold with U-type micro groove is fabricated making utilizing of the benefit of the mechanical micro machining technology. A shaping machining process is adapted using 3 axis degree of freedom micro machining system and single crystal natural diamond tool. A brass and a electroless nickel materials are used for mold fabrication. Machining force, chip shape and machined surface are investigated from the experiment and an optimal machining condition is found based on the examined problems from the micro cutting process.

• 폴리머
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• 제38권2호
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• pp.220-224
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• 2014

콘택트렌즈용 하이드로젤로의 단백질 흡착량을 시간에 따라 분석하여 계면으로 확산되는 단백질 흡착 반응속도를 연구하였다. HEMA(hydroxyethylmethacrylate)계열 하이드로젤과 silicone계열 하이드로젤을 단백질(알부민 또는 IgG)용액에 침지시킨 후 단백질 흡착량을 시간에 따라 측정하였다. 모든 하이드로젤로의 단백질 흡착량은 단시간(10분)에 급격히 증가한 후 90분 동안 변화 없이 일정하였다. 빠른 단백질 분자의 확산에도 불구하고 계면에너지 감소는 한 시간 이상 진행되는데 이는 계면 탈수 현상이 한 시간 이상 진행되기 때문으로 이해된다. 계면에너지와 단백질 흡착량의 상관관계를 이해하여 콘택트렌즈 재질로의 단백질 흡착 반응 속도의 메커니즘을 분석하였다.

• 한국레이저가공학회지
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• 제14권2호
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• pp.24-29
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• 2011

The design of a telecentric f-${\theta}$ lens with a field of view (FOV) $30^{\circ}$ and an effective focal length of 1000mm is presented. The optical stop is placed at the front plane and the design is based on a geometric ray tracing technique, and the designed system consists of a series of convex and concave lenses. The designed f-${\theta}$ lens showed a considerable reduction in weight with a simplified structure and resulted in a good performance in the designated FOV. Detail analysis of rays is also presented. 653nm (red laser), 586nm (green laser), and 468nm (blue laser) were simulated as a light source and image illuminating source. The developed optical design requires 7 pieces of lenses made of SF1, N-FK56, N-LAK33, and BK7 glass materials. With optimal parametric design, the effective focal length was calculated to be 974.839mm which is very close to the initial design target. For the manufacturing purpose, the dimensions of lens curvature and thickness were truncated with error ranging 0.1% to 3.2%. As a result, the overall error was calculated to be 3.2% which can be still tolerable for display, laser material, and machining processing.