실내공간에서 패브릭의 확산효과를 활용한 LED 조명 디자인의 특성 및 경향

양보람 ( Yang Boram ),정강화 ( Chung Kangwha ) 한국디자인트렌드학회 2011 한국디자인포럼 Vol.31 No.-

실내공간에서 빛은 단지 밝기를 제공한다는 의미를 넘어 하나의 소재로 인식되고 있다. 실내공간에서는 빛을 확산이 중요하기 때문에 조명기구에 있어 확산성과 빛의 효과를 고려한 투과면 소재의 선택이 필요하다. LED가 실내공간으로 적용이 확대됨에 따라 LED의 특성에 최적화된 조명기구의 개발이 요구되고 있다. 특히 LED는 소형화된 점광원, 글레어 방지를 이유로 빛의 확산 메커니즘에 대한 연구가 필요하다. 따라서 본 논문에서는 LED 조명 확산소재로써 패브릭의 가능성을 제시하고 패브릭의 확산효과를 활용한 LED 조명 디자인의 특성 및 경향을 연구하기 위해 사례를 선정하여 분석하였다. 분석의 기준은 형태적 특성과 표현 특성으로 분류했다. 사례들을 형태적 특성으로 분석한 결과 패브릭을 활용한 LED 조명이 독립적인 조명기구형태에서 공간에 일체화된 형태로 확장되는 경향이 나타났다. 또한 패브릭의 표현 특성인 드레이프성, 신축성, 촉감에 따라 다른 확산면이 형성되어 빛 확산효과가 나타남을 확인할 수 있었다. 본 연구의 결과는 LED 조명의 확산소재로써 패브릭이 디자인적 측면에서 형태적 자유도와 다양한 빛 확산효과의 장점이 있음을 보여준다. 패브릭 소재의 활용을 통해 스마트 라이팅 테크놀로지를 이질감 없이 자연스럽게 실내 환경에 적용시킬 수 있을 것으로 보인다. The light in interior space is being recognized as a material itself rather than just a thing that provides the brightness. Because of importance of the diffusion of light in interior, the choice of material considering the effects of diffusion and transmission of light is needed in lighting fixtures. In particular, there has to be an urgent research in regard to a mechanism of the diffusion of light on account of minimized light point resource, straightness of the light, and the protection of glare. Accordingly in this study, selected cases were analyzed to present a possibility of the usage of fabric as diffusing material and study characteristics and tendency of LED lighting design utilizing diffusion of fabric. Basis of analysis is classified with morphological characteristic and express characteristics. As a result, the analysis according to morphological characteristics, there was a tendency that the LED lighting utilizing fabric extends from a form of independent lighting fixture to a form unified in a space appeared. Also various diffusion surface formed and diffusing effect of light appeared to express characteristics of fabric such as drape, stretch, and tactile impression. This study shows that the fabric, a diffusing material of LED lighting has an advantage of morphological freedom and various lighting diffusion effects as in design aspect. It is expected to have smart writing technology applied to an interior environment in a natural way without a sense of difference through a utilization of fabric material.

$CeO_2$첨가와 도포물질의 입자크기가 화산공정을 이용한 고온초전도 후막의 특성에 미치는 영향

임성훈,강형곤,홍세은,윤기웅,황종선,한병성 한국전기전자재료학회 2001 전기전자재료학회논문지 Vol.14 No.2

For the fabrication of YBa$_2$Cu$_3$O$_{x}$ thick film using diffusion process between $Y_3$BaCuO$_{5}$ and BaO+CuO, each material was selected as substrate and doping material. In this paper, we investigated the characteristic of YBa$_2$Cu$_3$O$_{x}$ thick film due to both addition of CeO$_2$into substrate and initial particle size of doping material. Through X-ray diffraction patterns and SEM photographs, the variation of composition and thickness of the formed phase was observed. It was from the experiment obtained that the addition of CeO$_2$into $Y_2$BaCuO$_{5}$ substrate and the initial particle size of doping material play important part in promoting the reaction between substrate and doping material.aterial.

개별 마감재의 유효확산계수를 이용한 복층마감 후의 VOCs방출량 예측에 관한 연구

권경우,윤창현,박준석 대한건축학회 2007 대한건축학회논문집 Vol.23 No.7

The purpose of this research is to predict VOCs emission rates from multi-layers materials, which are composed of single-layer materials having various VOCs emission rates, by using effective diffusion coefficients of the single-layer materials. Cup method was used for measuring effective diffusion coefficients of three VOCs, such as toluene, ethylbenzene and decane, in seven single-layer materials and two multi-layer materials. The effective diffusion coefficients of three VOCs are estimated from 0.310-12 to 697.810-12[m2/sec], and they are decreased according to molecular weight of the diffused compounds in the single-layer materials. Resistance values, [sec/m] of mass transfer rate of the multi-layer materials, which are calculated from the analogy of mass transfer rate and electric charge, show good fit for the measured values from the cup method. From the simulation and the measurements, it is found that TVOCs emission rates from multi-layer materials can be predicted using the effective diffusion coefficients and initial concentrations of each single-layer materials through numerical methods.

표면피복재 및 단면수복재로 보수된 콘크리트의 염화물 침투 특성에 관한 연구

신상헌(Shin Sang-Heon),강인석(Kang In-Seok),고재원(Koh Jae-Won),이한승(Lee Han-Seung) 대한건축학회 2009 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.29 No.1(구조계)

Reinforced concrete is one of the most popular material in the construction industry. However, its durability decreased by rebar corrosion which generates crack of structure. To recover durability of structure, it is removed and refilled with finishing material that the area damaged by chloride ion. But, studies are insufficient in spite of necessity of the study about penetration in concrete with finishing material. Therefore, in this study, calculated diffusion coefficient finishing material and patching repaired concrete by RCPT(Rapid Chloride Penetration Test), and predicted about sustenance life from chloride ion penetration after freezing-thawing by Finite Element Method(FEM). Compare with no finishing species, it figured out 42%, 72% diffusion coefficient reduction in case of concrete with finishing species, section repaired species. And freezing and thawing cycle increases, chloride ion diffusion increased. Finite element analysis result, sustenance life of concrete established 48 years, surface finishing established 50 years, than concrete 48 years, section restoration material established more than 100 years.

표면피복재 및 단면수복재로 보수된 콘크리트의 동결융해 저항성과 염화물 침투 특성에 관한 연구

신상헌(Shin Sang-Heon),강인석(Kang In-Seok),고재원(Koh Jae-Won),이한승(Lee Han-Seung) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.8

Reinforced concrete is one of the most popular material in the construction industry. However, its durability decreased by rebar corrosion which generates crack of structure. To recover durability of structure, it is removed and refilled with finishing material that the area damaged by chloride ion. But, studies are insufficient in spite of necessity of the study about penetration in concrete with finishing material. Therefore, in this study, calculated diffusion coefficient finishing material and patching repaired concrete by RCPT(Rapid Chloride Penetration Test), and predicted about sustenance life from chloride ion penetration after freezing-thawing by Finite Element Method(FEM). Compare with no finishing species, it figured out 42%, 72% diffusion coefficient reduction in case of concrete with finishing species, section repaired species. And freezing and thawing cycle increases, chloride ion diffusion increased. Finite element analysis result, sustenance life of concrete established 48 years, surface finishing established 50 years, than concrete 48 years, section restoration material established more than 100 years.

Understanding the Effects of Surface Finish on Diffusion Bonding of AZ31 Alloys

Matthew Criado,Abhijit Roy,John Ohodnicki,Nicholas Tondravi,Hannah Fischer,Alejandro Almarza,Howard A. Kuhn,Prashant N. Kumta 대한용접접합학회 2023 대한용접·접합학회지 Vol.41 No.5

Methods to optimize the diffusion bonding (DB) process while also creating lap joints were investigated using AZ31, the commercial Mg alloy, focusing primarily on studying the effects of varying conventional process parameters and more importantly, exploring the influence of surface roughness on creating an acceptable strong bond. The results indicate that when contact is made between surface areas of roughness (Ra > 0.2 ㎛) diffusion is facilitated at reduced process parameters of time and temperature. Furthermore, this early bond initiation combined with the optimized DB process parameters results in a stronger bond with strengths increasing by ~ 150% in comparison to the DB samples created with a smooth surface finish. Additionally, less than 20% total overall distortion is observed while preserving a uniform microstructure of consistent grain sizes in the material over the entire joining region compared with the parent material.

Two-dimensional sheet of germanium selenide as an anode material for sodium and potassium ion batteries: First-principles simulation study

Sannyal, Arindam,Zhang, Zhengqing,Gao, Xingfa,Jang, Joonkyung Elsevier 2018 Computational materials science Vol.154 No.-

<P><B>Abstract</B></P> <P>Recently, two-dimensional layered materials have come forth as encouraging candidates for advanced electronic and optoelectronic applications. Anode materials with high energy-density and diffusion rate are fundamental features for the development of non-lithium ion batteries. Based on the density functional theory calculations, we propose a two-dimensional (2D) sheet of germanium selenide (GeSe) as a promising anode material for a sodium (Na) or potassium (K) ion battery. The phonon dispersion and formation energy verify the dynamic and thermal stability of the GeSe sheet. A substantial charge transfer from the alkali metal atoms to the GeSe sheet enhances the electrical conductivity of GeSe, favorable for an anode material. The Na or K diffusion on the GeSe sheet has a low energy barrier of 0.10 eV, giving a rapid charge/discharge rate without metal clustering. The GeSe sheet has a high theoretical capacity for both Na (707 mA h g<SUP>−1</SUP>) and K (530 mA h g<SUP>−1</SUP>) ion batteries. The GeSe sheet also gives a low and stable electrode potential comparable to that of a commercial anode material.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Strong adsorption of the metal atoms prevents the metal clustering. </LI> <LI> Significant charge transfer changes the semiconducting GeSe into metallic. </LI> <LI> Alkali metal diffusion on the germanium selenide monolayer is anisotropic. </LI> <LI> The open circuit voltages are in the ranges of other commercial anode materials. </LI> <LI> The 2D germanium selenide gives very high capacity for Na-ion and K-ion batteries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

동해 남동해역 해양투기물질의 확산 특성

홍도웅(DO-UNG HONG),김종규(JONG-KYU KIM),류청로(CHEONG-RO RYU) 한국해양공학회 2002 韓國海洋工學會誌 Vol.16 No.1

The diffusion characteristics of an ocean dumping material in the south-eastern East/Japan Sea related to regulate the physical characteristics with the observation and the hydraulic experiment are investigated. The main results are as follows :<br/> (1) Spying CTD observation result of the area of Jung in the East/Japan Sea, the ocean dumping area had influenced the Tsushima Warm Current of high temperature and salinity. Horizontal turbulent diffusivity is 1.913×10<SUP>7</SUP> ㎠/sec by drogue tracking.<br/> (2) From the experiment of settling, the initial settling velocity of each material is 1.0~2.7 ㎝/sec according to the specific gravity and initial concentration. In the pycnocline, particles didn't settle under the pycnocline any more and accumulated. It is signified that calculation of the sedimentation rate of the ocean dumping material including of vertical diffusion must be regard the pycnocline in the ocean area have well-developed pycnocline.<br/> (3)Vertical turbulent diffusivity were 2.219×10<SUP>-8</SUP>~8.874×10<SUP>-4</SUP> ㎠/sec from the experiment of settling. And, the pycnocline influenced the vertical turbulent diffusivity.

Gas diffusion in an automotive catalyst in an unsteady state

Hiroshi Yamada,Tomohiko Tagawa,Satoru Kato,Naoki Takahashi 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

The influence of gas diffusion is often ignored because the washcoat layer is thin. Therefore, in addition todeveloping new catalytic materials, modifying the washcoat pores is important for improving effectivegas diffusivity. The gas diffusion phenomena in an unsteady state in an experimentally simulated washcoatlayer were evaluated by the pulse injection method. Wicke–Kallenbach diffusion cell was used. Effective diffusion coefficients obtained in an unsteady state were compared to those obtained in a steadystate. The effective diffusion coefficients were similar to the values obtained under a steady state, exceptfor low-molecular-weight gasses, due to the difference in mean molar speed between the evaluating gasand atmospheric gas.

Electrochemical properties of CuO hollow nanopowders prepared from formless Cu–C composite via nanoscale Kirkendall diffusion process

Won, Jong Min,Kim, Jong Hwa,Choi, Yun Ju,Cho, Jung Sang,Kang, Yun Chan Elsevier 2016 Journal of Alloys and Compounds Vol.671 No.-

<P><B>Abstract</B></P> <P>Hollow CuO nanopowders are prepared using a simple spray drying process that relied on nanoscale Kirkendall diffusion; these nanopowders have potential applications in lithium-ion batteries. Citric acid is used as both the carbon source material and chelating agent and plays a key role in the preparation of the hollow nanopowders. The formless Cu–C composite that formed as an intermediate product transforms into slightly aggregated CuO hollow nanopowders after post-treatment at 300 and 400 °C under an air atmosphere. The CuO hollow nanopowders exhibit higher initial discharge capacities and better cycling performances than those of the filled-structured CuO nanopowders, which are prepared at a post-treatment temperature of 500 °C under an air atmosphere. The discharge capacities of the CuO nanopowders post-treated at 300, 400, and 500 °C for the 150<SUP>th</SUP> cycle at a current density of 1 A g<SUP>−1</SUP> are 793, 632, and 464 mA h g<SUP>−1</SUP>, respectively, and their capacity retentions calculated from the maximum discharge capacities are 88, 80, and 73%, respectively. The CuO nanopowders with hollow structures exhibit better structural stability for repeated lithium insertion and desertion processes than those with filled structures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hollow CuO nanopowders are prepared using a simple spray drying process. </LI> <LI> Cu–C composite transforms into CuO hollow nanopowders by Kirkendall diffusion. </LI> <LI> Hollow CuO nanopowders show good electrochemical properties for lithium-ion storage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>