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A Study on the Characteristics of Oil-water Separation in Non-point Source Control Facility by Coalescence Mechanism of Spiral Buoyant Media (나선형 부유 고분자 여재의 Coalescence 특성을 이용한 비점오염원 저감시설의 유수분리특성 연구)

  • Kang, Sung-Won;Kim, Seog-Ku;Kim, Young-Im;Yun, Sang-Leen;Kim, Soo-Hae;Kim, Mee-Kyung
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.8
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    • pp.950-955
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    • 2007
  • Non-point source control system which had been designed only for oil-water separation in the fields of oil refinery and garage was upgraded in this research for the removal of runoff pollutants in impervious urban area. Pollutants including oil from driveway and bridge were eliminated by two types of pathway in the system. One is the coalescence mechanism that the oil droplets in the runoff come into contact with each other in the spiral buoyant media surface and form larger coalesced droplets of oil that are carried upstream to the oil layer. The other is the precipitation that solids in runoff were settled by gravity in the system. In this research, coalescing characteristics of oil and water separation were investigated through image analyses, and efficiencies of the non-point source control system were evaluated using dust in driveway and waste engine oil. Media made of high density and high molecular weight polyethylene was indeterminate helical shape and had sleek surface by analysing SEM photographs and BET. Surface area and specific gravity of media which were measured directly were 1,428 $mm^2$ and 45.3 $kg/m^3$ respectively. From the image analyses of the oil droplets photographs which were taken by using microscope, it was proved clearly that the coalescence was the main pathway in the removal of oil from the runoff. Finally, the performances of the non-point source control system filled up with the media were suspended solid $86.6\sim95.2%$, $COD_{Cr}$, $87.3\sim95.4%$, n-Hexane extractable materials $71.8\sim94.8%$ respectively.

The necessary number of profile lines for the analysis of concrete fracture surfaces

  • Konkol, Janusz;Prokopski, Grzegorz
    • Structural Engineering and Mechanics
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    • v.25 no.5
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    • pp.565-576
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    • 2007
  • The article describes a technique for the measurement of the level of complexity of fracture surfaces by the method of vertical sections, and a performed statistical analysis of the effect of profile lines on the fractographic and fractal parameters of fractures, i.e. the profile line development factor, $R_L$, and the fracture surface development factor, $R_S$, (as defined by the cycloid method), as well as the fractal dimension, $D_C$, (as determined by the chord method), and the fractal dimension, $D_{BC}$, (as determined by the box method). The above-mentioned parameters were determined for fracture surfaces of basalt and gravel concretes, respectively, which had previously been subjected to fracture toughness tests. The concretes were made from mixtures of a water/cement ratio ranging from 0.41 to 0.61 and with a variable fraction of coarse aggregate to fine aggregate, $C_{agg.}/F_{agg.}$, in the range from 1.5 to 3.5. Basalt and gravel aggregate of a fraction to maximum 16 mm were used to the tests. Based on the performed analysis it has been established that the necessary number of concrete fracture profile lines, which assures the reliability of obtained testing results, should amount to 12.

Light Scattering Amplification on Dye Sensitized Solar Cells Assembled by Hollyhock-shaped CdS-TiO2 Composites

  • Lee, Ga-Young;Lee, Hu-Ryul;Um, Myeong-Heon;Kang, Mi-Sook
    • Bulletin of the Korean Chemical Society
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    • v.33 no.9
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    • pp.3043-3047
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    • 2012
  • To investigate the scattering layer effect of a $TiO_2$ multilayer in dye-sensitized solar cells (DSSCs), we designed a new DSSC system, assembled with a CdS-$TiO_2$ scattering layer electrode. A high-magnification SEM image exhibited hollyhock-like particles with a width of 1.5-2.0 ${\mu}m$ that were aggregated into 10-nm clumps in a hexagonal petal shape. The efficiency was higher in the DSSC assembled with a CdS-$TiO_2$ scattering layer than in the DSSC assembled with $TiO_2$-only layers, due to the decreased resistance in electrochemical impedance spectroscopy (EIS). The short-circuit current density ($J_{sc}$) was increased by approximately 7.26% and the open-circuit voltage ($V_{oc}$) by 2.44% over the 1.0 wt % CdS-$TiO_2$ composite scattering layer and the incident photon-to-current conversion efficiency (IPCE) in the maximum peak was also enhanced by about 5.0%, compared to the DSSC assembled without the CdS-$TiO_2$scattering layer.

Analyzing the Effect of Si Surface Morphology on Front Electrode Formation (전면 전극 형성 시 표면 형상이 미치는 영향 분석)

  • Han, Hyebin;Choi, Dongjin;Kang, Dongkyun;Park, HyunJung;Bae, Suhyun;Kang, Yoonmook;Lee, Hae-Seok
    • Current Photovoltaic Research
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    • v.7 no.4
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    • pp.130-133
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    • 2019
  • The Ag crystallite formed during the formation of the front electrode forms a contact between the metal of the electrode and the emitter of the cell. Contact between the electrode and emitter plays an important role in collecting electrons generated by the solar cell. Therefore, Ag crystallite formation is an important factor. In order for solar cells to have good characteristics, it is important to understand the factors influencing the Ag crystallite formation. Factors affecting the formation of Ag crystallites include Si emitter, morphology, Si defect and firing temperature. The influence of surface morphology on Ag crystallite formation was confirmed throughout this study. In the case of fine texturing, the Ag crystallites were formed at the pointed parts. The finer the texturing, the sharper areas and more Ag crystallites were formed. This was confirmed by SEM image and FF calculation.

Development of Thermal Sensor Devices in the $BaTiO_3$ Systems ($BaTiO_3$계 박막형 열전센서소자 개발)

  • Song, Min-Jong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05d
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    • pp.100-104
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    • 2003
  • $BaTiO_3$ ceramic thin films were manufactured by rf/dc magnetron sputter technique. We have investigated crystal structure, surface morphology and PTCR(positive-temperature coefficient of resistance) characteristics of the specimen depending on second heat-treatment temperatures. Second heat treatments of the specimen were performed in the temperature range of 400 to $1350^{\circ}C$. X-ray diffraction patterns of $BaTiO_3$ thin films show that the specimen heat treated below $600^{\circ}C$ is an amorphous phase and the one heat treated above $1100^{\circ}C$ forms a poly-crystallization. In the specimen heat-treated at $1300^{\circ}C$, a lattice constant ratio (c/a) was 1.188. Scanning electron microscope(SEM) image of $BaTiO_3$ thin films of the specimen heat treated in between 900 and $1100^{\circ}C$ shows a grain growth. At $1100^{\circ}C$, the specimen stops grain-growing and becomes a poly-crystallization.

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The Study of WET Cleaning Effect on Deep Trench Structure for Trench MOSFET Technology (Trench MOSFET Technology의 Deep Trench 구조에서 WET Cleaning 영향에 대한 연구)

  • Kim, Sang-Yong;Jeong, Woo-Yang;Yi, Keun-Man;Kim, Chang-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.88-89
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    • 2009
  • In this paper, we investigated about wet cleaning effect as deep trench formation methods for Power chip devices. Deep trench structure was classified by two methods, PSU (Poly Stick Up) and Non-PSU structure. In this paper, we could remove residue defect during wet. cleaning after deep trench etch process for non-PSU structure device as to change wet cleaning process condition. V-SEM result showed void image at the trench bottom site due to residue defect and residue component was oxide by EDS analysis. In order to find the reason of happening residue defect, we experimented about various process conditions. So, defect source was that oxide film was re-deposited at trench bottom by changed to hydrophobic property at substrate during hard mask removal process. Therefore, in order to removal residue defect, we added in-situ SCI during hard mask removal process, and defect was removed perfectly. And WLR (Wafer Level Reliability) test result was no difference between normal and optimized process condition.

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Composite Effect of Ag and Au in the $Bi_{1.84}\;Pb_{0.34}\;Sr_{1.91}\;Ca_{2.03}\;Cu_{3.06}\;O_{10+\delta}$(110K Phase) High-Tc Superconductor (Ag와 Au가 혼합된 $Bi_{1.84}\;Pb_{0.34}\;Sr_{1.91}\;Ca_{2.03}\;Cu_{3.06}\;O_{10+\delta}$ 산화물 고온초전도체의 초전도특성)

  • 이민수
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.6
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    • pp.241-248
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    • 2003
  • $Bi_{1.84}Pb_{0.34}Sr_{1.91}Ca_{2.03}Cu_{3.06}O_{10+\delta}$ high $T_{c}$ superconductors containing Ag as an additive were fabricated by a solid-state reaction method. The superconducting properties, such as the structural characteristics, the critical temperatures, the grain size and the image of mapping on the surface were investigated. Samples with Ag and Au of 50 wt% each were sintered at various temperature(820~$850^{\circ}C$). The structural characteristics, the microstructure of surface and the critical temperature with respect to the each samples were analyzed by XRD and SEM, EDS and four-prove methode respectively. The critical temperature showed the result which the Ag additive samples are higher than Au additive samples. The microstructure of the surface showed the tendency which the Ag additive samples become more minuteness than Au additive samples.

CSR Expectation from Fashion Firms and its Impact on Brand Equity (패션기업에 대한 CSR기대와 브랜드 자산에 미치는 영향)

  • Ahn, Soo-Kyoung;Ryou, Eunjeong
    • Fashion & Textile Research Journal
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    • v.15 no.1
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    • pp.73-83
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    • 2013
  • This study explores the ideal corporate social responsibility(CSR) that fashion consumers expect from a fashion firm in the identification of dimensions and levels of consumer expectations as well as examines the impact of CSR expectations on customer-base brand equity. The data of 315 adults were collected through a nationwide online survey. In order to analyze the data, this study employed Confirmatory factor analysis (CFA), paired t-test, structural equation modeling(SEM), and descriptive analysis. This study first identified seven fashion CSR expectations (environmental, ethical, social, internal management, philanthropic, economic, and legal expectations). Internal management and environmental activities were highly expected from fashion firms; however, economic activity was low in expectations. Five models separately tested the relationship between CSR expectations and brand equity (trustworthiness, attachment, performance, social image, and value). Economic, environmental, internal management, social and ethical CSR expectations influenced customer-based brand equity; however, philanthropic and legal expectations did not influence any dimension of customer-based brand equity. This study provides a framework of ideal CSR from a consumer perspective and suggests that fashion marketers should focus on economic, environmental, internal management, social and ethical CSR activities to meet the expect Haitians of fashion consumers and build stronger brand equity.

The Studies on the Fabrication and Properties of Friction Materials toy Aluminium Alloy Disk (알루미늄 합금 디스크용 마찰재의 제조 및 그 특성에 관한 연구)

  • 손태관;장상희;제갈영순
    • Composites Research
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    • v.16 no.4
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    • pp.22-28
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    • 2003
  • This article deals with the manufacture and test results of asbestos-free friction material for Aluminium at toy disk. In order to obtain optimum formulation, various formulations of fibres, matrix, modifiers, fillers, etc were designed and evaluated. The constant friction and brake dynamometer tests were performed to know weak and strong point for each friction material. The C21 formulation of various tested formulations exhibited superior friction constant(0.38∼38), fade rate (18%) by JASO C406 test mode and maximum wear 1.6 mm. disc wear 0.08 mm by JASO C427 test mode. The surface morphology of AL alloy disk(before and after test) was observed by Scanning Electron Microscope(SEM) and Image Analyzer.

Hydrogen production by catalytic decomposition of methane over carbon black catalyst in a fluidized bed (카본블랙 촉매를 이용한 유동층 반응기에서 메탄의 직접 열 분해에 의한 수소생산 연구)

  • Jung, Jae-Uk;Nam, Woo-Seok;Yun, Ki-Jun;Lee, Dong-Hyun;Han, Gui-Young
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.284-287
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    • 2005
  • A fluidized bed reactor made of quartz with 0.055 m I.D. and 1.0 m in height was employed for the thermocatalytic decomposition of methane to produce $CO_2 - free$ hydrogen. The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. The methane decomposition rate with the carbon black N330 catalyst was quickly reached a quasi-steady state rate and remained for several hour. The methane decomposition reaction was carried out at the temperature range of $850-925^{\circ}C$, methane gas velocity of $1.0U_{mf}\;3.0U_{mf}$ and the operating pressure of 1.0 atm. Effect of operating parameters such as reaction temperature, gas velocity on the reaction rates was investigated. The produced carbon by the methane decomposition was deposited on the surfaces of carbon catalysts and the morphology was observed by SEM image.

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