• Title/Summary/Keyword: Photo spot

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Active Alignment and Performance Evaluation of Micro Hybrid Lens for Small Form Factor Optical Pickup (초소형 광 픽업용 하이브리드 렌즈의 능동 정렬 및 성능평가)

  • Kang Sung-Mook;Lee Jin-Eui;Cho Eun-Hyoung;Sohn Jin-Seung;Park No-Cheol;Park Young-Pil
    • 정보저장시스템학회:학술대회논문집
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    • 2005.10a
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    • pp.154-159
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    • 2005
  • The next generation of optical storage systems requires higher numerical aperture (NA) objective lenses and shorter wavelength laser in order to improve the unit areal density. A blu-ray technology satisfies a miniaturization and a high capacity which are the requirements of the portable device. In this paper, we analyze the optical performance of hybrid micro lens and do active alignment. The hybrid micro lens is manufactured by using a wafer based fabrication technology. Optical components of hybrid micro lens are evaluated. The measurement of the optical power, the spot size and the wavefront error awe performed to evaluate the hybrid micro lens with NA 0.85. Using the measured data, we estimate if the performance of hybrid micro lens corresponds to the designed performance. After the performance of hybrid micro lens is evaluated, the integrated optical pickup and the hybrid micro lens are assembled by active alignment using UV curing and the optical performance of SFFOP is satisfied with BD specifications.

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Active Alignment and Performance Evaluation of Micro Hybrid Lens for Small Form Factor Optical Pickup (초소형 광 픽업용 하이브리드 렌즈의 능동 정렬 및 성능평가)

  • Kang, Sung-Mook;Lee, Jin-Eui;Cho, Eun-Hyoung;Sohn, Jin-Seung;Park, No-Cheol;Park, Young-Pil
    • Transactions of the Society of Information Storage Systems
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    • v.2 no.1
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    • pp.79-84
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    • 2006
  • The next generation of optical storage systems requires higher numerical aperture(NA) objective lenses and shorter wavelength laser in order to improve the unit areal density. A blu-ray technology satisfies a miniaturization and a high capacity which are the requirements of the portable device. In this paper, we analyze the optical performance of hybrid micro lens and do active alignment. The hybrid micro lens is manufactured by using a wafer based fabrication technology. Optical components of hybrid micro lens are evaluated. The measurement of the optical power, the spot size and the wavefront error are performed to evaluate the hybrid micro lens with NA 0.85. Using the measured data, we estimate if the performance of hybrid micro lens corresponds to the designed performance. After the performance of hybrid micro lens is evaluated. the integrated optical pickup and the hybrid micro lens are assembled by active alignment using UV curing and the optical performance of SFFOP is satisfied with BD specifications.

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An Analysis Study of Landscape View Point on Urban Histo-Cultural Area - Focused on Bukchon Hanok Village - (도시 내 역사문화미관지구 경관조망지점 분석에 관한 연구 - 북촌한옥마을을 대상으로 -)

  • Choi, Yoo;Son, Seung-Woo;Lee, Kang-Hyun;Im, Seung-Bin
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.3
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    • pp.80-86
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    • 2012
  • This study is about selecting Landscape Viewpoint on Bukchon Hanok Village, Jongno-Gu, Seoul. The process on selecting photo spots was focused on visualizing elements, and it was hard to find an objective standard for selecting landscape viewpoint. Therefore, by literature review and site study, this study selects more objective and empirical Landscape View Point on Bukchon. Landscape Viewpoint Standards are Traditional Hanok Landscape, Historical Heritage Landscape, Alley Street Landscape, City Architecture Landscape, and Natural Forest Landscape. By Landscape Preference and Character of Place survey, this study finds out another Landscape Viewpoint and correlation of those variables. A coefficient of correlation is 0.846, and its correlation is considerably high. Through this result, it could provide a concrete standard for selecting Landscape View Point and a preliminary information for finding Landscape View Point on Histo-Cultural area.

The study of optimal reduced-graphene oxide line patterning by using femtosecond laser pulse (펨토초 레이저 펄스를 이용한 환원된 그래핀의 최소 선폭 패턴 구현에 관한 연구)

  • Jeong, Tae-In;Kim, Seung-Chul
    • Journal of the Korea Convergence Society
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    • v.11 no.7
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    • pp.157-162
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    • 2020
  • In recent years, laser induced graphene process have been intensively studied for eco-friendly electronic device such as flexible electronics or thin film based energy storage devices because of its simple and effective process. In order to increase the performance and efficiency of an electronic device using such a graphene patterned structure, it is essential to study an optimized laser patterning condition as small as possible linewidth while maintaining the graphene-specific 2-dimensional characteristics. In this study, we analyzed to find the optimal line pattern by using a Ti:sapphire femtosecond laser based photo-thermal reduction process. we tuned intensity and scanning speed of laser spot for generating effective graphene characteristic and minimum thermal effect. As a result, we demonstrated the reduced graphene pattern of 30㎛ in linewidth by using a focused laser beam of 18㎛ in diameter.

New Whitening agent: Kojyl-APPA

  • Hwang, Jae-Sung;Kim, Duck-Hee;Soomi Anh;Baek, Heung-Soo;Park, Hyunjung -Jin;Lee, Jin-Young;Lee, Byeong-Gon;Ihseop Chang;Kang, Hak-Kee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.27 no.1
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    • pp.119-131
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    • 2001
  • Exposure of the human skin to UV-light can cause sun-tanning, photoaging and even photo-carcinogenesis. Melanin is important in protecting the skin against UV damage, but excessive or uneven melanin production can lead to the formation of freckles and aged spot. Control of hyperpigmentation is becoming even more important as aged population continues to grow. These needs led us to develop effective and safe depigmenting-agent, kojyl 3-aminopropyl phosphate (kojyl-APPA), called Whitegen. The development of whitegen was based on the fact that phosphate group of 3-aminopropyl phosphate can make kojic acid more compatible to the skin membrane and more stable. Instability of kojic acid has been a problem in cosmetic use. The insertion of phosphoester group has been recognized as a powerful tool to improve such physical properties as solubility and stability, because the phosphodiester residue is well characterized as a non-toxic moiety, having a high affinity for cell membranes. Kojyl-APPA showed no tyrosinase inhibition effect compared to kojic acid in vitro, but showed tyrosinase inhibition effect in situ. It means that kojyl-APPA is converted to kojic acid enzymatically in cells. Kojyl-APPA showed the inhibitory activity on melanin synthesis in mouse melanoma and normal humal melnaocytes and also showed long-lasting stability in comparison with its original form (kojic acid). Kojyl-APPA showed depigmenting effects when applied to UVB-induced hyperpigmentated region of guinea pig skin. Based on these results, kojyl 3-aminopropyl phosphate can be used as a safe and effective ingredient for the brightness and cleanness of skin.

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Where to spot: individual identification of leopard cats (Prionailurus bengalensis euptilurus) in South Korea

  • Park, Heebok;Lim, Anya;Choi, Tae-Young;Baek, Seung-Yoon;Song, Eui-Geun;Park, Yung Chul
    • Journal of Ecology and Environment
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    • v.43 no.4
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    • pp.385-389
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    • 2019
  • Knowledge of abundance, or population size, is fundamental in wildlife conservation and management. Camera-trapping, in combination with capture-recapture methods, has been extensively applied to estimate abundance and density of individually identifiable animals due to the advantages of being non-invasive, effective to survey wide-ranging, elusive, or nocturnal species, operating in inhospitable environment, and taking low labor. We assessed the possibility of using coat patterns from images to identify an individual leopard cat (Prionailurus bengalensis), a Class II endangered species in South Korea. We analyzed leopard cat images taken from Digital Single-Lense Relfex camera (high resolution, 18Mpxl) and camera traps (low resolution, 3.1Mpxl) using HotSpotter, an image matching algorithm. HotSpotter accurately top-ranked an image of the same individual leopard cat with the reference leopard cat image 100% by matching facial and ventral parts. This confirms that facial and ventral fur patterns of the Amur leopard cat are good matching points to be used reliably to identify an individual. We anticipate that the study results will be useful to researchers interested in studying behavior or population parameter estimates of Amur leopard cats based on capture-recapture models.

An Analysis of Photoacoustic Signals Excited by Excimer Pulsed Laser (엑시며 레이저 펄스에 의해 여기된 광음향신호 분석)

  • Yi, Chong-Ho;Jun, Kye-Suk
    • The Journal of the Acoustical Society of Korea
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    • v.16 no.1
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    • pp.39-46
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    • 1997
  • In this paper, the PA(PhotoAcoustic) signals excited in metals by Xef, KrF excimer laser pulse were detected by a PZT transducer, and its transforming machanism and directivity patterns were analysed. The laser energy density in irradiation spot divides the PA trasnsorming machanism to be classified into thermoelastic and plasma regime, and the transforming machanisms in two regimes are different from each other. Based on theoretical model, it is predicted that shear wave is greater than longitudinal in the thermoelastic regime and longitudinal is greater than shear wave by reaction force in plasma regime. These predictions were verified through experiments by using of the XeF excimer pulsed laser of 480nm center-wavelength and the KrF excimer pulsed laser of 248nm. Also, for its directivity pattern, an arrival angle of the maximum longitudinal energy was around $60^{\circ}$ and maximum shear energy was around $30^{\circ}$ in the thermoelastic regime, and an arrival angle of maximum longitudinal energy was shown on nomal to the surface and maximum shear energy was represented in about $30^{\circ}$ in plasma regime.

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Improving Curing Rate and Physical Properties of Korean Dendropanax Lacquer with Thermal and Photo Initiator by Dual Curing (이중경화법을 이용한 열개시제 및 광개시제가 배합된 황칠도료의 경화속도 촉진 및 물성향상 연구)

  • Hwang, Hyeon-Deuk;Moon, Je-Ik;Park, Cho-Hee;Kim, Hyun-Joong;Hwang, Baik
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.4
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    • pp.333-340
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    • 2010
  • The Korean Dendropanax lacquer, made from a natural resinous sap from Dendropanax orbifera Lev., was used as a golden and transparent varnish for the traditional artifacts (armor uits, helmets, arrowheads, etc.) to make them be brilliant golden color. The cured film of the acquer has excellent protective properties such as weatherability, water resistance, and nticorrosive. But, one of disadvantages is that takes a long time and much energy to fulfill curing the lacquer. The chemical constituents of the lacquer contained conjugated diene compounds s the photopolymerizable monomers. These monomers easily polymerized in sunlight to form olden-colored, hard-coating films in a short time. Photooxidation may be one of the most mportant reactions in the chemistry of the lacquer. Although the Korean Dendropanax Lacquer hould be dried to a thoroughly dry stage to achieve optimal film properties, curing with elevated emperatures may be required for the protracted curing time at atmospheric temperature. So we ntended to accelerate the curing rate of the lacquer by dual curing of thermal and radiation uring. The effect of thermal initiator on the thermal curing reaction was evaluated by monitoring he changes in double bond peak with FT-IR. Then the curing rate of the lacquer blended with hermal initiator and photoinitiator together was measured during dual curing using a RPT with V spot curing machine. Thermal initiator not only accelerated the curing rate but also improved he physical property. And the curing rate of the Korean Dendropanax lacquer was improved by ual curing method of thermal and UV curing. According to these results, the application area of he Korean Dendropanax lacquer could be expanded to surface coatings for electronic devices uch as mobile phones or electronics.

Environmental Interpretation on soil mass movement spot and disaster dangerous site for precautionary measures -in Peong Chang Area- (산사태발생지(山沙汰發生地)와 피해위험지(被害危險地)의 환경학적(環境學的) 해석(解析)과 예방대책(豫防對策) -평창지구(平昌地區)를 중심(中心)으로-)

  • Ma, Sang Kyu
    • Journal of Korean Society of Forest Science
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    • v.45 no.1
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    • pp.11-25
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    • 1979
  • There was much mass movement at many different mountain side of Peong Chang area in Kwangwon province by the influence of heavy rainfall through August/4 5, 1979. This study have done with the fact observed through the field survey and the information of the former researchers. The results are as follows; 1. Heavy rainfall area with more than 200mm per day and more than 60mm per hour as maximum rainfall during past 6 years, are distributed in the western side of the connecting line through Hoeng Seong, Weonju, Yeongdong, Muju, Namweon and Suncheon, and of the southern sea side of KeongsangNam-do. The heavy rain fan reason in the above area seems to be influenced by the mouktam range and moving direction of depression. 2. Peak point of heavy rainfall distribution always happen during the night time and seems to cause directly mass movement and serious damage. 3. Soil mass movement in Peongchang break out from the course sandy loam soil of granite group and the clay soil of lime stone and shale. Earth have moved along the surface of both bedrock or also the hardpan in case of the lime stone area. 4. Infiltration seems to be rapid on the both bedrock soil, the former is by the soil texture and the latter is by the crumb structure, high humus content and dense root system in surface soil. 5. Topographic pattern of mass movement spot is mostly the concave slope at the valley head or at the upper part of middle slope which run-off can easily come together from the surrounding slope. Soil profile of mass movement spot has wet soil in the lime stone area and loose or deep soil in the granite area. 6. Dominant slope degree of the soil mass movement site has steep slope, mostly, more than 25 degree and slope position that start mass movement is mostly in the range of the middle slope line to ridge line. 7. Vegetation status of soil mass movement area are mostly fire field agriculture area, it's abandoned grass land, young plantation made on the fire field poor forest of the erosion control site and non forest land composed mainly grass and shrubs. Very rare earth sliding can be found in the big tree stands but mostly from the thin soil site on the un-weatherd bed rock. 8. Dangerous condition of soil mass movement and land sliding seems to be estimated by the several environmental factors, namely, vegetation cover, slope degree, slope shape and position, bed rock and soil profile characteristics etc. 9. House break down are mostly happen on the following site, namely, colluvial cone and fan, talus, foot area of concave slope and small terrace or colluvial soil between valley and at the small river side Dangerous house from mass movement could be interpreted by the aerial photo with reference of the surrounding site condition of house and village in the mountain area 10. As a counter plan for the prevention of mass movement damage the technics of it's risk diagnosis and the field survey should be done, and the mass movement control of prevention should be started with the goverment support as soon as possible. The precautionary measures of house and village protection from mass movement damage should be made and executed and considered the protecting forest making around the house and village. 11. Dangerous or safety of house and village from mass movement and flood damage will be indentified and informed to the village people of mountain area through the forest extension work. 12. Clear cutting activity on the steep granite site, fire field making on the steep slope, house or village construction on the dangerous site and fuel collection in the eroded forest or the steep forest land should be surely prohibited When making the management plan the mass movement, soil erosion and flood problem will be concidered and also included the prevention method of disaster.

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Reading Deviations of Glass Rod Dosimeters Using Different Pre-processing Methods for Radiotherapeutic in-vivo Dosimetry (유리선량계의 전처리 방법이 방사선 치료 선량 측정에 미치는 영향)

  • Jeon, Hosang;Nam, Jiho;Park, Dahl;Kim, Yong Ho;Kim, Wontaek;Kim, Dongwon;Ki, Yongkan;Kim, Donghyun;Lee, Ju Hye
    • Progress in Medical Physics
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    • v.24 no.2
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    • pp.92-98
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    • 2013
  • The experimental verification of treatment planning on the treatment spot is the ultimate method to assure quality of radiotherapy, so in-vivo skin dose measurement is the essential procedure to confirm treatment dose. In this study, glass rod dosimeter (GRD), which is a kind of photo-luminescent based dosimeters, was studied to produce a guideline to use GRDs in vivo dosimetry for quality assurance of radiotherapy. The pre-processing procedure is essential to use GRDs. This is a heating operation for stabilization. Two kinds of pre-processing methods are recommended by manufacturer: a heating method (70 degree, 30 minutes) and a waiting method (room temperature, 24 hours). We equally irradiated 1.0 Gy to 20 GRD elements, and then different preprocessing were performed to 10 GRDs each. In heating method, reading deviation of GRDs at same time were relatively high, but the deviation was very low as time went on. In waiting method, the deviation among GRDs was low, but the deviation was relatively high as time went on. The meaningful difference was found between mean reading values of two pre-processing methods. Both methods present mean dose deviation under 5%, but the relatively high effect by reading time was observed in waiting method. Finally, GRD is best to perform in-vivo dosimetry in the viewpoint of accuracy and efficiency, and the understanding of how pre-processing affect the accuracy is asked to perform most accurate in-vivo dosimetry. The further study is asked to acquire more stable accuracy in spite of different irradiation conditions for GRD usage.