• Title/Summary/Keyword: High reflection

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

  • Sung Yong Yang;Bo Min Kim;Hyeji Park;Gyu Hwan Kim;Jaehyeung Park
    • Textile Coloration and Finishing
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    • v.35 no.2
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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.

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

  • Hong, YunSeok;Han, Wooyoung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.10a
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    • pp.143-145
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    • 2022
  • With the spread of the Internet around the world, devices connected to the Internet are gradually increasing. In addition, the number of distributed reflection service attacks (DrDoS), an attack that maliciously requests large responses by deceiving IPs as if the attacker was a victim, using vulnerabilities in application protocols such as DNS, NTP, and CLDAP, is increasing rapidly. It is believed that the security threat of distributed reflection service attacks will not disappear unless ISPs establish appropriate countermeasures to IP Spoofing. Therefore, this paper describes the security threat and response status of distributed reflection service attacks based on IP Spoofing.

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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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    • v.27 no.5_6
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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
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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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
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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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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Comparison & Analysis of Anti-Reflection Coatings for Crystalline Si Solar cells (결정질 실리콘 태양전지의 반사방지막 비교 분석)

  • Cho, Kyeong-Yeon;Lee, Ji-Hun;Lee, Soo-Hong;Lee, Kyu-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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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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Tribological and Optical Characteristics of Silica Coating for Anti-reflection Coating of Solar Cell (태양전지의 반사방지막을 위한 Silica 코팅의 트라이볼로지 및 광학적 특성 평가)

  • Kim, Hae-Jin;Kim, Dae-Eun
    • Transactions of the Society of Information Storage Systems
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    • v.6 no.2
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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.

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

  • Kang, Dong-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.2
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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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    • v.4 no.2
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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.

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

  • Ko, Kun-Soo;Seo, Won-Seok;Lee, Chang-Hoon;Kim, Jong-Seoung
    • 대한공업교육학회지
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    • v.39 no.1
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    • pp.227-246
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    • 2014
  • The purpose of this study is to suggest the desirable direction toward the creative hand-on activities suitable for the characters of the technical high school students by examining the teachers' recognition of sub-factors of creative activities in technical high school and analysing whether the factors are properly utilized. Respondents of this study were 393 teachers at the Technical high school in South Korea. The questionnaire survey on the recognition of creative hand-on activities consisted of questions, which are importance and reflection, from 32 sections in 5 fields. The summary of the results through this study is as following. First, In the results of importance analysis of teachers in technical high school, in club activity field, 'the invention' of 'academic activity', 'film-art' in 'culture-art activity', 'challenge activity' in 'sports activity', 'school specialized major' in 'work practice activity', 'scout federation', 'Red Cross youth activity' in 'youth group activity' were seemed to be higher. Second, In the results of reflection analysis, it was found that the 'academy, culture-art', 'sports activity' fields were similarly reflected in importance thought by teachers in technical high school. However, for 'the work practice activity' and 'youth group activity', except 'the school specialized major', all fields are not properly reflected, independent of importance. For 'the work practice activity', analyses of importance and reflection seemed to be alike but for 'the youth group activity', there was a significant difference between them.