비가간섭광을 이용한 내부전반사 홀로그래픽 리소그라피

이준섭,박우제,이지환,송석호,이성진,Lee, Joon-Sub,Park, Woo-Jae,Lee, Ji-Whan,Song, Seok-Ho,Lee, Sung-Jin 한국광학회 2009 한국광학회지 Vol.20 No.6

Recently, with increasing demand for flat-panel display product, methods for large area patterning are required. TIR (total internal reflection) holographic photo-lithography isstudied as one of the methods of large area lithography. In conventional TIR holography, light sources for hologram recording and image reconstruction are coherent beams such as laser beams. If the image is reconstructed with an incoherent light source such a UV lamp, the image noise from the coherence of light will be reduced and the UV lamp will be a better light source for large area exposure. We analyzed the effect of spectral bandwidth and angular bandwidth of the light source in image reconstruction and verified image blurring with experiments. For large area patterning which has micro-scale line width, it is expected that TIR holographic photo lithography by UV lamp will become a low-noise and low-priced technique. 최근 디스플레이 기기의 수요가 증대되면서 대면적 노광에 대한 요구가 증대되고 있는데, 내부전반사(total internal reflection: TIR)홀로그래픽 리소그라피는 대면적 노광을 위한 효과적인 방법으로 연구가 진행되고 있다. TIR 홀로그래피에서는 일반적으로 레이저를 이용하여 영상을 기록하고 재생한다. 그러나 자외선 램프와 같은 비가간섭광을 이용하여 재생한다면, 가간섭성에 의해 나타나는 영상잡음을 줄일 수 있고, 대면적 노광에도 보다 용이할 것이다. TIR 홀로그램의 재생을 위하여 자외선 램프를 이용할 때, 램프의 유한한 선폭과 확산각이 재생 영상에 미치는 영향을 분석하고, 재생패턴에 나타나는 선폭 확대 결과를 실험을 통하여 검증하였다. ${\mu}m$ 규모의 선폭을 갖는 대면적 패턴을 TIR 홀로그램으로부터 얻기 위한 재생 광원으로, 가간섭성 광원인 레이저 대신 저잡음성과 경제성을 갖춘 일반적인 자외선 램프의 사용이 가능할 것으로 기대된다.

대면적 리소그래피를 위한 홀로그램 영상의 연결과 연결 영역에서의 간섭무늬 제거

이준섭,박우제,이지환,송석호,이성진,김의석,Lee, Joon-Sub,Park, Woo-Jae,Lee, Ji-Whan,Song, Soek-Ho,Lee, Sung-Jin,Kim, Oui-Serg 한국광학회 2009 한국광학회지 Vol.20 No.1

본 논문에서는 대면적 리소그래피를 위하여 홀로그램 영상을 연결하여 기록 물질에 저장하고 이를 마스크로 이용하는 노광 방법을 제안하고 구현하였으며, 홀로그램 영상을 재생하는 과정에서 발생되는 영상 연결 부분에서의 간섭 무늬를 제거하였다. 연결하고자 하는 영상은 DMD(digital micro-mirror device)로 표시하였으며, DMD 영상은 축소 광학계를 통하여 기록 물질에 저장되었다. 기록 물질은 전동 스테이지로 이동되도록 하여, DMD로 표시되는 영상이 기록 물질에 연속적으로 저장되도록 하였다. 이러한 방법으로 저장되는 연결된 영상은 재생광에 의하여 노광에 사용되는데, 재생광의 간섭성에 의하여 연결부분에 간섭무늬가 발생된다. 간섭무늬는 노이즈로 작용하는데, 다중 노광에 의한 홀로그램 영상의 기록과 재생을 이용하여 이를 제거하였다. 본 논문에서는 DMD와 전동 스테이지를 이용하여 영상을 연결하여 기록하고, 다중 노광에 의한 영상 기록 방법을 이용하여, 간섭 무늬가 제거된 연결된 영상을 구현하고 이를 리소그래피에 적용하였다. In this study, we propose an image stitching method for large-area holographic photo lithography. In this method, a hologram medium become a hologram mask for lithography. And the mask has information for stitched images. These images are recorded by signal images which are controlled with DMD (digital micro-mirror device), and serial hologram recording is achieved with a motorized linear stage. Using this method, fringe seams appear on the stitching area. To remove these fringe seams, double exposure holographic lithography is tried. Each stitched image is recorded and reconstructed with a different reference beam. The experiments confirm that fringe seams are removed.

키토산 겔을 이용한 포름알데하이드 차폐 시트 개발

김소연(So-Yeon Kim),김미소(Mi-So Kim),탁상민(Sang Min Tak),이지환(Ji Whan Lee),심소연(So Yeon Sim),주은희(Eun Hee Joo),김성배(Sung Bae Kim),김창준(Chang-Joon Kim) 한국생물공학회 2014 KSBB Journal Vol.29 No.3

Sick-building syndrome occurs when indoor air is polluted with harmful volatile organic compounds such as formaldehyde which are contained in furniture or new building materials. In this study, formaldehyde-shielding chitosangel sheet was developed and its performance was evaluated. Chitosan and agar were dissolved in acetic acid solution. The optimal concentrations of chitosan, acetic acid and agar were 3, 3, and 2.5 %(w/w). Formaldehyde was spreaded on gypsum board and then wall paper was attached on it by using glue. When chitosan-gel sheet was attached on this control board, the amount of formaldehyde released from the board was decreased by 63% than in control board. On the other hand, decrease in formaldehyde releasing was only 32% when liquid solution of chitosan was spreaded on the control board. This result clearly indicates that chitosan-gel sheet removes formaldehyde more effectively than liqud solution of chitosan. Furthermore, this type of sheet is more applicable to new building than spraying type.

남은음식물 퇴비 시용에 따른 토양의 이화학성 변화와 고추생육에 미치는 영향

유영석(Young-Seok Yu),장기운(Ki-Woon Chang),이지환(Ji-Whan Lee) 유기성자원학회 2001 유기물자원화 Vol.9 No.4

본 연구는 유기성 폐자원의 효율적인 처리 방법의 일환인 퇴비화를 이용하여 생산된 남은 음식물 퇴비(이하 음식물 퇴비)를 고추 재배지에 시용량 별로 처리한 후 작물 생육과 토양의 이화학성 변화에 미치는 영향을 평가하기위해 수행되었다. 처리구는 무처리구, 대조구 (20 Mg ha-1의 돈분 퇴비 ) , 음식물퇴비를 20, 40, 60, 80 Mg ha-1을 시용한 처리구 등 모두 6 개를 두었으며 3 반복, 난괴법을 이용하였다. 토양 pH는 음식물 퇴비의 시용량이 많을수록 상승하는 경향이 컸으며 전기 전도도를 비롯한 다른 토양 특성도 비슷한 경향을 보였다. 또한 음식물 퇴비 시용량이 많을수록 용적비중은 낮아지고 공극율은 증가하는 상관관계를 보였다. 작물생육은 퇴비 시용량이 많은 처리구에서 초기 생육이 저조하였으며 1차 생육조사에서 그 차이를 뚜렷하게 확인할 수 있었다. 고추의 생중량은 초기 생육에서 저해를 받은 처리구에서 특히 적었으며 음식물 퇴비의 20 Mg ha-1처리구는 대조구에 비해 낮았지만 큰 차이는 크지 않았다. 음식물 퇴비의 수용성 유기성분과 염류에 의한 초기 생육부진과 고추 수확량 감소를 감안한다면 시용량은 30 Mg ha 1을 초과하지 말아야 할 것으로 판단된다. 음식물 퇴비를 연용 시험을 통해작물 생육과 토양에 미치는 영호t을 평가하여 음식물 퇴비의 시용량을 설정하는 것이 바람직할 것으로 생각된다. This experiment was carried out to evluate the effect of residual food compost appücation on plant growth and physicochemical properries of soil when residual food compost made from the composting process as part of organlc waste recycling was appüed in soil as variable rate. The treatments were composed non-fertilizer treatment, control treatment appüed with pig compost 20 Mg(D.W.) ha and residual food compost treatments each of appüed with 20, 40, 60, 80 Mg(D.W.) ha"' and were randomized complere block design with rhree replicarion. Soil pH after experiment was more increased as more increase application of residual food composr. Other chemical properries of soil including EC were also showed the similar results. The plant growth in treatmenrs applied mucl1 of residuct food composr ar the early growth srage was very damaged and these result rs were proved ar the fìrsr growth measurement Production of the red pepper especially reduced in treatments raken growth demage at the early stage and that of 20 Mg ha" treatment almost same as control trearment. Bulk densiry was reduced but porosiry was increased according to increase of residual food compost application. Considering the reduction of red pepper production and demage of growth ar the early srage by plenry of salt and water soluble application volume of residual food composr was nor permirred over of30 Mg ha-'. Addirively, to setrle the appücation volume of residual food compost and ro evaluare the plant growth and changes of physicochemical properties of soil, the resulrs raken ftom continual applying is concluded more imporranr than single applicarion.

LightGBM을 사용한 LNG 및 HFO 연료 소비 예측 모델링

김현주(Hyun Ju Kim),박민규(Min Gyu Park),이상봉(Sang Bong Lee),이지환(Ji Whan Lee) 한국멀티미디어학회 2024 멀티미디어학회논문지 Vol.27 No.2

SiCp/AZ91 Mg 기 복합재료의 인장특성에 미치는 강화상입도 및 열처리의 영향

이지환,이준서,이두면,김가연,안지환 대한금속재료학회(대한금속학회) 1995 대한금속·재료학회지 Vol.33 No.7

The present study aims at investigating the effect of SiC particulates size and heat-treatment on the tensile properties of SiC_P/AZ91 Mg composites. The AZ91 Mg alloy powders were made by wet attrition milling from AZ91 Mg machined chips and the powders size was below 240㎛. The SiC particulates size used as a reinforcement was 8, 30 and 50㎛, respectively. The Mg powders and SiC particulates (10 vol%) were mixed using a V-blender for 2 hours. Both AZ91 Mg alloy powders and mixtures of AZ91 Mg alloy powders and SiC particulates were hot pressed at 400℃ to make round billets. The billets were hot extruded at extrusion temperature of 300℃ under extrusion ratio of 40:1. The extruded Mg matrix and SiC_P/AZ91 Mg composites were solution treated at 410℃ for 17 hours, quenched into ice water, and then aged at 170℃ for 40 hours. It was found that the ultimate tensile strength of as-extruded composites is much higher than that of the as-extruded Mg matrix. As SiC particulates size decreased, the U.T.S. of as-extruded composites tended to increase. This could be attributed to the matrix grain refinment caused by the present of SiC particulates and the reduction of crack formation by the fracture of SiC particulates during hot extrusion. After T_6 heat treatment, the U.T.S. of heat-treated composites was found to be superior to that of as-extruded composites. Also, the U.T.S. of the composites was considerably increased with decreasing particulates size after T_6 heat-treatment. The reason for this is the restriction of the matrix grain-coarsening by fine SiC particulates during solution treatment.

하지동맥 우회로술 후 당뇨병군과 비당뇨병군간의 이식편 개존율 비교

김영욱,허승,김상걸,이지환 대한혈관외과학회 2000 Vascular Specialist International Vol.16 No.2

Purpose: It is well known that leg amputaions are more common in diabetic than non-diabetic patients with arterial occlusive disease. However, the previous reports comparing the graft patencies following infrainguinal bypasses between diabetic and non-diabetic patients revealed a wide range of variance. We tried to determine whether there is a difference on the graft patency between diabetic and non-diabetic patients with infrainguinal arterial bypasses. Method: During the period from March, 1993 to December, 1999, 271 infrainguinal bypass grafts were implanted to the limbs with chronic atherosclerotic arterial occlusive disease at Kyungpook National University Hospital, Taegu, Korea. Among them, 193 limbs with autogenous reversed vein grafts were included in this study, which comprised of 65 limbs (34%) in diabetic and 128 limbs (66%) in non-diabetic patients. To compare the graft patencies between diabetic and non-diabetic patients, we divided them into 3 groups according to the levels of distal anastomosis. We used life table or Kaplan-Meier methods to calculate the cumulative primary patency rates and log-rank test to compare the graft patencies between the groups. Result: The sites of distal anastomosis were above-knee popliteal artery in 29.2%, below-knee popliteal artery in 40.0%, and infrapopliteal artery in 30.8% of diabetic patients, whereas above-knee popliteal artery in 21.1%, below-knee popliteal artery in 50.0%, and infrapopliteal artery in 28.9% of non-diabetic patients. Vein grafts used in the bypasses were 185 reversed greater saphenous veins, 5 spliced veins, and 3 arm veins. The cumulative primary patency rates at 1, 3 and 5 years were 86% (SE 5.0%), 74% (SE 7.6%) and 74% (SE 7.6%) respectively, in diabetic patients, while 84% (SE 3.7%), 73% (SE 5.2%) and 56% (SE 9.8%) respectively, in non-diabetic patients group. After comparing the patency rates between 2 groups at 3 different levels of distal anastomosis, there was no statistically significant (p$lt;0.05) difference at any level. Conclusion: We found that diabetes did not affect the primary graft patency following the lower extremity arterial bypasses using reversed vein grafts.