• 제목/요약/키워드: high reflection

검색결과 1,219건 처리시간 0.041초

그라비아 케미칼 프린팅 기술을 이용한 고내구성 재귀반사 코팅 직물 제조연구 (Development of Highly Durable Retroreflective Coating with Gravure Chemical Printing)

  • 양성용;김보민;박혜지;김규환;박재형
    • 한국염색가공학회지
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    • 제35권2호
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    • pp.98-106
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    • 2023
  • The recent surge in night walkers and pedestrian traffic accidents has led to an increased interest in retro-reflection-based products, leading to several studies on retro-reflection. Nonetheless, achieving high durability and dispersibility of retro-reflective glass beads in viscous polyurethane coating resin remains challenging. To address this issue, this study conduct to functionalize the surface of glass beads for covalent conjugation to coating resin to enhance their dispersibility and durability in the coating resin. The study evaluated the dispersibility, chemical composition, and retro-reflection properties of the functionalized glass beads and coating resin. The results showed that the functionalized glass beads conjugated to the polyurethane coating resin and exhibited excellent dispersibility, high durability, and maintained retro-reflection efficiency.

IP Spoofing을 이용한 분산 반사 서비스 거부 공격의 보안 위협과 대응 실태 연구 (A Study of security threats and response of Distribute Reflection Denial of Service Attack using IP spoofing)

  • 홍윤석;한우영
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2022년도 추계학술대회
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    • pp.143-145
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    • 2022
  • 전 세계적인 인터넷의 보급으로 인터넷과 연결된 기기들이 점차 늘어나고 있다. 이에 더불어 DNS, NTP, CLDAP 와 같이 응용 프로토콜의 취약점을 이용하여, 공격자가 피해자인 것처럼 아이피를 속여, 다량의 응답을 악의적으로 요청하는 공격인 분산 반사 서비스 거부 공격(DRDoS)이 급격하게 늘어나는 추세이다. ISP 들이 IP Spoofing에 대한 적절한 대비책을 수립하지 않으면 분산 반사 서비스 공격의 보안 위협은 사라지기 어려울 것으로 사료된다. 따라서 본 논문에서는 IP Spoofing에 기반한 분산 반사 서비스 공격의 보안 위협과 대응 실태에 관해 기술한다.

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INTERACTION OF SURFACE WATER WAVES WITH SMALL BOTTOM UNDULATION ON A SEA-BED

  • Martha, S.C.;Bora, S.N.;Chakrabarti, A.
    • Journal of applied mathematics & informatics
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    • 제27권5_6호
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    • pp.1017-1031
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    • 2009
  • The problem of interaction of surface water waves by small undulation at the bottom of a laterally unbounded sea is treated on the basis of linear water wave theory for both normal and oblique incidences. Perturbation analysis is employed to obtain the first order corrections to the reflection and transmission coefficients in terms of integrals involving the shape function c(x) representing the bottom undulation. Fourier transform method and residue theorem are applied to obtain these coefficients. As an example, a patch of sinusoidal ripples is considered in both the cases as the shape function. The principal conclusion is that the reflection coefficient is oscillatory in the ratio of twice the surface wave number to the wave number of the ripples. In particular, there is a Bragg resonance between the surface waves and the ripples, which is associated with high reflection of incident wave energy. The theoretical observations are validated computationally.

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The Study of N-type Crystalline Silicon Solar Cells by PC1D

  • Yi, Junsin;Jung, Junhee;Lau, Meng How
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.287.2-287.2
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    • 2014
  • PV (photovoltaic) has becoming an important industry to invest due to its high robustness and require very little maintenance which goes a long time. Solar cell fabrication involves a few critical processes such as doping to make the N-type and P-type silicon, contact metallization, surface texturization, and anti-reflection coatings. Anti-reflection coating is a kind of surface passivation which ensures the stability, and efficiency of the solar cell. Thus, I will focus on the changes happen to the solar cell due to the reflectance and anti-reflection coating by PC1D. By using the PC1D (solar cell simulation program), I would analysis the effect of reflectance on the N-type cell. At last I will conclude the result regarding what I learned throughout this experiment.

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STM Investigation of Methanol Adsorption on Al2O3/NiAl(110) Deposited by Pulsed Injection

  • Lee, Youn-Joo;Choi, E.;Lyo, In-Whan
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.318-318
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    • 2011
  • Etching of an ultrathin aluminum oxide film on NiAl(110) substrate by methanol is studied by home-built scanning tunneling microscopy at room-temperature. We deposited liquid methanol on thin alumina film by using a high speed solenoid valve suitable for deposition of thermally unstable molecules. It is found that only the reflection domain boundary between two domains was preferentially etched by methanol. Since the reflection domain boundary has many oxygen vacancies and irregular structures, judging from the fact, we assume that oxygen vacancies cause the chemically reactive phenomena of methanol in reflection domain boundary on an alumina film. The reactivity of the reflection domain boundary is attributed to the oxygen vacancies due to irregular structures. Similar reactivity is found on the oxygen deficient alumina produced on top of the intact alumina.

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결정질 실리콘 태양전지의 반사방지막 비교 분석 (Comparison & Analysis of Anti-Reflection Coatings for Crystalline Si Solar cells)

  • 조경연;이지훈;이수홍;이규상
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.221-222
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    • 2008
  • In Crystalline Si solar cells, Anti-Reflection Coating is contribute to improvement in energy conversion efficiency due to decrease of optical loss and recombination owing to surface passivation. Porous Si is formed electrochemical etching that uses chemical solution and anodization etching. So It gives that advantage in rapid process time and without high cost equipment. In this paper, We compare Porous Si with $SiO_2$/SiNx ARC and analyze that by anti-reflection coating.

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태양전지의 반사방지막을 위한 Silica 코팅의 트라이볼로지 및 광학적 특성 평가 (Tribological and Optical Characteristics of Silica Coating for Anti-reflection Coating of Solar Cell)

  • 김해진;김대은
    • 정보저장시스템학회논문집
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    • 제6권2호
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    • pp.68-73
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    • 2010
  • The interest in acquiring high efficiency solar cells has been steadily increasing due to various advantages such as low-cost installation, pollution free and everlasting energy generation. In order to raise the cell efficiency, there has been a lot of effort to develop effective anti-reflection coatings. In this work, the main objective was to investigate the effects of particle size and annealing temperature of silica anti-reflection coatings to maximize the cell efficiency as well as reliability. It was shown that the light transmittance could be increased by a few percent over a certain range of wavelength using the silica coating. Also, the tribological properties of the coating could be improved through the annealing process, which led to better reliability of the coating.

고성능 비정질실리콘 박막태양전지를 위한 전후면 계면에서의 빛의 효율적 관리 기술 (Light-managing Techniques at Front and Rear Interfaces for High Performance Amorphous Silicon Thin Film Solar Cells)

  • 강동원
    • 전기학회논문지
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    • 제66권2호
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    • pp.354-356
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    • 2017
  • We focused on light management technology in amorphous silicon solar cells to suppress increase in absorber thickness for improving power conversion efficiency (PCE). $MgF_2$ and $TiO_2$ anti-reflection layers were coated on both sides of Asahi VU ($glass/SnO_2:F$) substrates, which contributed to increase in PCE from 9.16% to 9.81% at absorber thickness of only 150 nm. Also, we applied very thin $MgF_2$ as a rear reflector at n-type nanocrystalline silicon oxide/Ag interface to boost photocurrent. By reinforcing rear reflection, we could find the PCE increase from 10.08% up to 10.34% based on thin absorber about 200 nm.

The Application of Machine Vision to IC Surface Inspection

  • Chung, Yi-Chan;Tsai, Chih-Hung;Lin, Yu-Tang
    • International Journal of Quality Innovation
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    • 제4권2호
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    • pp.50-64
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    • 2003
  • During IC inspection, which includes the two parts of Mark and Lead, the deviation of IC on the tape occurring in high speed movements usually generates light reflection effect, which in turn causes errors in IC recognition as measured by machine vision system. This research filters the light reflection effect by developing standard components, identifies the correct position of IC Lead, hence fixes the measurement errors or non-measurability caused by light reflection, avoids the resulting discontinued operation of measuring system, and improves the productivity.

공업계 고등학교 교사가 인식하는 창의적 체험활동 영역의 중요도 및 반영도 분석: 동아리활동을 중심으로 (A Study on Teachers' Recognition of Importance and Reflection on Creative Hands-on Activities at Technical High School: Focused on Club Activities)

  • 고건수;서원석;이창훈;김종승
    • 대한공업교육학회지
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    • 제39권1호
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    • pp.227-246
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    • 2014
  • 이 연구의 목적은 창의적 체험활동의 하위 영역인 동아리활동에 대한 공업계 고등학교 교사들의 인식을 조사하여, 향후 공업계 고등학교의 특성에 맞는 창의적 체험활동을 할 수 있도록 바람직한 방향을 제시하는데 필요한 기초 자료를 제공하는 것이다. 이 연구의 응답자는 전국의 공업계 고등학교에 재직 중인 교사 393명이고, 동아리활동에 대한 5개 영역 32개 분야의 문항(중요도, 반영도)으로 구성된 설문지를 활용하였다. 연구의 결과는 다음과 같다. 첫째, 동아리활동 영역에서 중요도 분석 결과, '학술 활동'은 '발명', '문화 예술 활 동'은 '영상예술', '스포츠 활동'은 '도전활동', '실습 노작 활동'은 '학교 특성화 전공', '청소년 단체 활동'은 '스카우트연맹'과 '청소년적십자'가 가장 높게 나타났다. 둘째, 동아리활동의 영역에서 반영도 분석 결과 '학술 활동', '문화 예술 활동' 및 '스포츠 활동' 영역은 대체적으로 공업계 고등학교 교사들이 생각하는 중요도에 비슷하게 반영되고 있었다. 하지만 '학교 특성화 전공'을 제외한 '실습 노작 활동'과 '청소년 단체 활동'의 경우는 중요도와는 별개로 모든 분야가 잘 반영되지 않고 있는 것으로 나타났다. '실습 노작 활동'은 중요도 분석과 반영도 분석이 비슷하게 나타났지만 '청소년 단체 활동'은 중요도에 비해 반영도 값이 현저히 낮게 나타나 중요도와 반영도에 큰 차이가 있었다.