• Title/Summary/Keyword: Layer Thickness

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Optical properties of top-emission organic light-emitting diodes due to a change of cathode electrode (음전극 변화에 따른 전면 유기 발광 소자의 광학적 특성)

  • Joo, Hyun-Woo;An, Hui-Chul;Na, Su-Hwan;Kim, Tae-Wan;Jang, Kyung-Wook;Oh, Hyun-Suk;Oh, Yong-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.345-346
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    • 2008
  • We have studied an emission spectra of top-emssion organic light-emitting diodes(TEOLED) due to a change of cathode and organic layer thickness. Device structure is Al(100nm)/TPD(xnm)/Alq3(ynm)/LiF(0.5nm)/cathode. And two different types of cathode were used; one is LiF(0.5nm)/Al(25nm) and the other is LiF(0.5nm)/Al(2nm)/Ag(30nm). While a thickness of hole-transport layer of TPD was varied from 35 to 65nm, an emissive layer thickness of Alq3 was varied from 50 to 100nm for two devices. A ratio of those two layer was kept to be about 2:3. Al and Al/Ag double layer cathode devices show that the emission spectra were changed from 490nm to 560nm and from 490nm to 560nm, respectively, when the total organic layer increase. Full width at half maximum was changed from 67nm to 49nm and from 90nm to 35nm as the organic layer thickness increases. All devices show that view angle dependent emission spectra show a blue shift. Blue shift is strong when the organic layer thickness is more than 140nm. Devece with Al/Ag double layer cathode is more vivid.

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The Quantification of TiO2 Thickness Using Color Values by Spectrophotometer and Chromameter (분광측색계, 색차계의 색 수치 값을 이용한 타이타늄 산화막의 두께 정량화)

  • Lee, Dayoung;Han, Ayoung;Ha, Dongheun;Yoo, Hyeonseok;Kim, Hunsik;Jung, Nagyeom;Jang, Kwanseop;Choi, Jinsub
    • Journal of Surface Science and Engineering
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    • v.51 no.3
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    • pp.157-163
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    • 2018
  • The anodic TiO2 layers which are prepared in various anodization conditions exhibit their specific color depending on the thickness of TiO2. In this study, the relationship between the color of TiO2 layer, which is grown by PEO (Plasma electrolytic oxidation), and the thickness of the TiO2 layer is investigated. To evaluate the color change of the TiO2 layer, the value of color (dEab) is measured and calculated by spectrophotometer and chromameter. As a result, it is found that dEab values and thickness of TiO2 layers form a linear relationship with meaningful formular. This formula can be helpful to quantify the thickness of the TiO2 layer by the numerical dEab values. In this process, the spectrophotometer shows more precise results than the chromameter dose. If fluoride ions (F) are included in the electrolyte, it will affect the dEab values of the TiO2. layer. This is against the propensity, which is analyzed by XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy). It is important that the formular suggested in this study provides other metals which can be also anodized with the possibility of quantifying the thickness of the TiO2 layer by the dEab values.

Estimation of Reinforced Railway Roadbed by Geosynthetics on Frost and Bearing Capacity (토목섬유로 보강된 철도노반의 동상 및 지지력 평가)

  • 심재범;채영수
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.11c
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    • pp.117-128
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    • 1999
  • Geosynthetics have been studied especially Korean Railway earth works from the outset and have proved successful in both technical and economic terms. Hitherto Geosynthetics have been given consideration chiefly in dimensioning the requisite track subbase thickness, but have not been considered when calculating the thickness of the frost protection layer. this often made it impossible to reduce the thickness of the subbase. The article therefore puts forward a proposal for considering the German Geosynthetics in dimensioning the requisite thickness of the frost protection layer.

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Reinforcement of Soft Soil Subgrade for High-Speed Railroad Using Geocell (연약지반상 고속철도 노반 축조시 지오셀 시스템의 효과)

  • 김진만;조삼덕;윤수호;정문경;김영윤
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.11c
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    • pp.129-141
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    • 1999
  • This paper presents the results of plate load test and dynamic load test performed to evaluate the performance of geocell where it is used to reinforce soft subgrade for high-speed railroad. Efficacy of geocell was observed in increase in bearing capacity of subgrade and reduction of thickness of reinforced sub-ballast. Plate load tests were carried out at four different places with varying foundation soil strength as a function of number of geocell layer, type of filler material, thickness of cover soil, and the presence of non-woven geotextile. Dynamic load tests were performed in a laboratory. The test soil chamber consists of, from the bottom, 50 cm thick clayey soil, one layer of geocell filled with crushed stone, 10 cm thick crushed stone cover, reinforced sub-ballast of varying thickness, 35 cm thick ballast. This configuration was determined based on the results of numerical analysis and plate load tests. For each set of the dynamic load tests, loads were applied more than 80,000 times. One layer of geocell underlying a 10 cm thick cover soil led to an increase in bearing capacity three to four times compared to a crushed stone layer of the same thickness substituted for the geocell and cover soil layer. Given the test conditions, the thickness of reinforced sub-ballast can be reduced by approximately 35 cm with the presence of geocell.

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Thin Film Growth and Evaluation Method for Conventional Co-Cr Based Perpendicular Magnetic Recording Media: Problems and New Solutions

  • Saito, Shin;Hoshi, Fumikazu;Hasegawa, Daiji;Takahashi, Migaku
    • Journal of Magnetics
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    • v.7 no.3
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    • pp.115-125
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    • 2002
  • We proposed a novel method to evaluate the magnetic properties of the initial layer and the columnar structure separately for CoCr-based perpendicular recording media. We show that the thickness of the initial layer and the intrinsic magnetocrystalline anisotropy of columnar structure can be quantitatively evaluated using the plotted product of perpendicular anisotropy to magnetic film thickness versus magnetic film thickness (Kuexp. × dmag. vs. dmag. plot). Based on the analyses, it is found that: (1) compared with CoCrPtTa media, CoCrPtB media have relatively thin initial layer, and have fine grains with homogeneous columnar structure with c-plane crystallographic orientation; (2) CoCrPtB media can be grown epitaxially on Ru or CoCr/C intermediate layer, and as the result, the magnetic properties of the media within thin thickness region of dmag. 20 nm is significantly improved; (3) the key issue of material investigation for CoCr-based perpendicular recording media will be focused on how to fabricate c-plane-oriented columnar grains well isolated with nonmagnetic substance in epitaxial-growth media, while maintaining the thermal stability of the media.

The Effect of Oxide Layer Thickness to the Scale Defects Generation during Hot finish Rolling (열연사상 압연시 스케일 결함발생에 미치는 산화피막 두께의 영향)

  • 민경준
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.08a
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    • pp.412-422
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    • 1999
  • Scale defects generated on the strip surface in a tandem finishing mill line are collected from the strip trapped among the production mills by freezing the growing scale on the strip by the melt glass coating and shutting down the line simultaneously. The samples observed of its cross sectional figure showed the process of scale defect formation where the defects are formed at the base metal surface by thicker oxidized scale during each rolling passes. The properties of the oxidized layer growth both at rolling and inter-rolling are detected down sized rolling test simulating carefully the rolling condition of the production line. The thickness of the oxidized layer at each rolling pass are simulated numerically. The critical scale thickness to avoid the defect formation is determined through the expression of mutual relation between oxidized layer thickness and the lanks of the strip called quality for the scale defects. The scale growth of scale less than the critical thickness and also to keep the bulk temperature tuning the water flow rate and cooling time appropriately. Two units of Inerstand Cooler are designed and settled among the first three stands in the production line. Two units of scale defect is counted from the recoiled strip and the results showed distinct decrease of the defects comparing to the conventionaly rolled products.

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Superconducting critical temperature in FeN-based superconductor/ferromagnet bilayers

  • Hwang, T.J.;Kim, D.H.
    • Progress in Superconductivity and Cryogenics
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    • v.18 no.2
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    • pp.5-7
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    • 2016
  • We present an experimental investigation of the superconducting transition temperatures, Tc, of superconductor/ferromagnet bilayers with varying the thickness of ferromagnetic layer. FeN was used for the ferromagnetic (F) layer, and NbN and Nb were used for the superconducting (S) layer. The results were obtained using three different-thickness series of the S layer of the S/F bilayers: NbN/FeN with NbN thickness, dNbN9.3nm and dNbN10nm, and Nb/FeN with Nb thickness dNb15nm. Tc drops sharply with increasing thickness of the ferromagnetic layer, dFeN, before maximal suppression of superconductivity at dFeN6.3nm for dNbN10nm and at dFeN2.5nm for dNb15nm, respectively. After shallow minimum of Tc, a weak Tc oscillation was observed in NbN/FeN bilayers, but it was hardly observable in Nb/FeN bilayers.

Evaluation of extension in service life and layer thickness reduction of stabilized flexible pavement

  • Nagrale, Prashant P.;Patil, Atulya
    • Advances in Computational Design
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    • v.3 no.2
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    • pp.201-212
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    • 2018
  • Decrease in availability of suitable subbase and base course materials for highway construction leads to a search for economic method of converting locally available troublesome soil to suitable one for highway construction. Present study insights on evaluation of benefits of stabilization of subgrade soils in term of extension in service life (TBR) and layer thickness reduction (LTR). Laboratory investigation consisting of Atterberg limit, Compaction, California Bearing Ratio, unconfined compressive strength and triaxial shear strength tests were carried out on two types of soil for varying percentages of stabilizers. Vertical compressive strains at the top of unstabilized and stabilized subgrade soils were found out by elastoplastic finite element analysis using commercial software ANSYS. The values of vertical compressive strains at the top of unstabilized and stabilized subgrade, were further used to estimate layer thickness reduction or extension in service life of the pavement due to stabilization. Finite element modeling of the flexible pavement layered structure provides modern technology and sophisticated characterization of materials that can be accommodated in the analysis and enhances the reliability for the prediction of pavement response for improved design methodology. If the pavement section is kept same for unstabilized and stabilized subgrade soils, pavement resting on lime, fly ash and fiber stabilized subgrade soil B will have service life 2.84, 1.84 and 1.67 times than that of unstabilized pavement respectively. The flexible pavement resting on stabilized subgrade is beneficial in reducing the construction material. Actual savings would depend on the option exercised by the designer for reducing the thickness of an individual layer.

Numerical Analysis of Effects of Velocity Inlet and Residual Layer Thickness of Resist on Bubble Defect Formation (레지스트 잔류층 두께와 몰드 유입속도가 기포결함에 미치는 영향에 대한 수치해석)

  • Lee, Woo Young;Kim, Nam Woong;Kim, Dong Hyun;Kim, Kug Weon
    • Journal of the Semiconductor & Display Technology
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    • v.14 no.3
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    • pp.61-66
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    • 2015
  • Recently, the major trends of NIL are high throughput and large area patterning. For UV NIL, if it can be proceeded in the non-vacuum environment, which greatly simplifies tool construction and greatly shorten process times. However, one key issue in non-vacuum environment is air bubble formation problem. In this paper, numerical analysis of bubble defect of UV NIL is performed. Fluent, flow analysis focused program was utilized and VOF (Volume of Fluid) skill was applied. For various resist-substrate and resist-mold angles, effects of velocity inlet and residual layer thickness of resist on bubble defect formation were investigated. The numerical analyses show that the increases of velocity inlet and residual layer thickness can cause the bubble defect formation, however the decreases of velocity inlet and residual layer thickness take no difference in the bubble defect formation.

Accuracy Enhancement in Direct & Adaptive Slicing of a Rotational Surface (회전곡면의 직접ㆍ적응 단면화에 있어서 정밀도 향상)

  • 박정환;신양호
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.1
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    • pp.185-191
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    • 2000
  • Direct & adaptive slicing of sculptured surfaces in RP improves, quality & accuracy of the final product, compared to the slicing with uniform layer thickness or the slicing of facets (ie, STL). Present D&A slicing procedures adaptively compute the next layer thickness based on the surface information of current sliced contour, which assumes constant normal curvature values. In some cases, however. such assumption leads to intolerable slicing result which cannot correctly consider the entire local feature shape. We propose improved adaptive slicing algorithms which can determine near-optimal layer thickness, including illustrated examples.

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