• Title/Summary/Keyword: Layer Thickness

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Prediction of Residual Layer Thickness of Large-area UV Imprinting Process (대면적 UV 임프린팅 공정에서 잔류층 두께 예측)

  • Kim, Kug Weon
    • Journal of the Semiconductor & Display Technology
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    • v.12 no.2
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    • pp.79-84
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    • 2013
  • Nanoimprint lithography (NIL) is the next generation photolithography process in which the photoresist is dispensed onto the substrate in its liquid form and then imprinted and cured into a desired pattern instead of using traditional optical system. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. Although one of the current major research trends of NIL is large-area patterning, the technical difficulties to keep the uniformity of the residual layer become severer as the imprinting area increases more and more. In this paper, with the rolling type imprinting process, a mold, placed upon the 2nd generation TFT-LCD glass sized substrate(370×470mm2), is rolled by a rubber roller to achieve a uniform residual layer. The prediction of residual layer thickness of the photoresist by rolling of the rubber roller is crucial to design the rolling type imprinting process, determine the rubber roller operation conditions-mpressing force & feeding speed, operate smoothly the following etching process, and so forth. First, using the elasticity theory of contact problem and the empirical equation of rubber hardness, the contact length between rubber roller and mold is calculated with consideration of the shape and hardness of rubber roller and the pressing force to rubber roller. Next, using the squeeze flow theory to photoresist flow, the residual layer thickness of the photoresist is calculated with information of the viscosity and initial layer thickness of photoresist, the shape of mold pattern, feeding speed of rubber roller, and the contact length between rubber roller and mold previously calculated. Last, the effects of rubber roller operation conditions, impressing force & feeding speed, on the residual layer thickness are analyzed with consideration of the shape and hardness of rubber roller.

Effects of turbulent boundary layer thickness on flow around a low-rise rectangular prism

  • Kim, Kyung Chun;Ji, Ho Seong;Seong, Seung Hak
    • Wind and Structures
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    • v.8 no.6
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    • pp.455-467
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    • 2005
  • The effects of upstream velocity profiles on the flow around a low-rise rectangular prism submerged in a turbulent boundary layer have been investigated. Three different boundary layer profiles are generated, which are characterized by boundary layer height, displacement thickness, and momentum thickness. Flow characteristics variations caused by the different layers such as those in turbulent kinetic energy distribution and locations of re-circulating cavities and reattachment points have been precisely measured by using a PIV (Particle Image Velocimetry) technique. Observations were made in a boundary layer wind tunnel at ReH=7900, based on a model height of 40 mm and a free stream velocity of 3 m/s with 15 - 20% turbulence intensity.

The Microscopic Surface Properties of Rhodamine Derivatives in EL System (EL시스템의 Rhodamine 유도체화합물의 표면특성)

  • 박수길;조성렬;손원근;조병호;임기조;이주성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.265-268
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    • 1997
  • Electroluminescent(EL) devices are constructed using multilayer organic thin film. A cell structure of glass substrate/Indium-Tinoxide/TPD as a hole transporting layer/Alq3+Rhodamine 101 perchrolate(Red3) as an emitting layer/Alq3 as an electrron transporting layer/Al as an electrode was employed. Optimal thickness of emitting layer in EL cell was performed from the viewpoint of the electronics properties of emitting layers. The general vapor-deposition method was used to control the thickness of omitting layer in EL devices and electro-optical characteristics were measured. It is clarified that controlling thickness of emitting layer in vapor-deposition film had an effect on the change of carrier injection and EL spectrum. The intensity of red omission with luminance of 81cd/m2 was achived at 11V driving voltage. The surface morphology of emitting layer in EL devices was investigated.

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Influence of Ambient Gas Composition on the Microstructure of Plasma Nitrocarburised SCM435 steel (플라즈마 질탄화처리된 SCM435강의 미세조직에 미치는 가스 조성의 영향)

  • Lee, In-Seop
    • Korean Journal of Materials Research
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    • v.12 no.6
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    • pp.427-430
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    • 2002
  • Plasma nitrocarburizing treatment was performed for SCM 435 steel by using a plasma ion nitriding system. The effects of the variation of nitrogen and methan contents upon the hardened layer was investigated. Both the thickness of the compound layer and the amount of ε phase in the compound layer increased with increasing nitrogen content. However, the thickness of the compound layer decreased due to unstable plasma for an atmosphere containing 90% N2 gas content in the gas mixture. The amount of εphase in the compound layer increased with increasing CH4 gas content. For CH4 gas content more than 2% in the gas mixture, the thickness of the compound layer decreased due to the formation of θ phase.

Analysis of the OLEDs Characteristics using Simulation (시뮬레이션을 이용한 유기발광다이오드 특성 해석)

  • Park, Young-Ha;Kim, Weon-Jong;Sin, Hyun-Taek;Cho, Kyung-Soon;Kim, Gwi-Yeol;Hong, Jin-Woong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.46-47
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    • 2008
  • Organic light-emitting diode is quick response speed, low power consumption and the self-interest has many advantages, such as insanity. So, organic light-emitting diode mechanism of light-emitting diode in order to more clearly understand the changes in the thickness of emitting materials for OLED characteristics of the simulation. emitting layer to a thickness of 10 [nm] ~ 100 [nm] changed the experiment, and hole transport layer 190 [nm] as a fixed. and emitting layer 10 [nm] ~ 100 [nm] to change the simulation results. Changes in the thickness of emitting layer gradually increased. depending on the emitting was 20 [nm] in the high 441 [lm / W] shows. and was gradually reduced. emitting layer 190 [nm] when fixed, hole transport layer, depending on changes in the thickness of 70 [nm] in the efficiency maximum value of 477 [lm / W], and was gradually reduced.

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Potential use of waste rubber shreds in drainage layer of landfills - An experimental study

  • Praveen, V.;Sunil, B.M.
    • Advances in environmental research
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    • v.5 no.3
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    • pp.201-211
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    • 2016
  • Laboratory tests were conducted to evaluate the performance of waste rubber shreds in leachate collection layer of engineered landfills. The study found that waste rubber shreds layer in combination with a gravel layer can be of potential use in landfill drainage system. To study the performance, conventional gravel along with waste rubber shreds were used in different combinations (with total layer thickness = 500 mm) as leachate collection media. For the laboratory study poly vinyl chloride (PVC) pipes were used. The size range of waste rubber shreds used were 25 mm to 75 mm in length and width = 10 to 20 mm. The gravel size used in the leachate collection media is 10 mm to 20 mm size. Performance study of 7 Test Cols. with different combinations of waste rubber shreds and gravel bed thickness were studied to find out the best combination. The study found that the Test Col.-3 having waste rubber shreds thickness = 200 mm and gravel layer thickness = 300 mm gave the best results in terms of percentage removal in various physicochemical parameters present in the leachate. Further to find the best size rubber shreds three more Test Cols - 8, 9 and 10 were constructed having the rubber shreds and gravel layer ratio same as that of Test Col.-3 but having rubber shreds width = 10 mm, 15 mm and 20 mm respectively. Based on the results obtained using Test Cols. 8, 9 and 10 the study found that smaller size rubber shreds gave bests results in terms of improvement in various leachate parameters.

Gas Tank Microleakage Reception Characteristics According to Thickness of the First Matching Layer of Ultrasonic Sensor (초음파 센서의 1차 정합층 두께에 따른 가스탱크 미세누설 수신특성)

  • Seo, Wonjun;Son, Seongjin;Im, Seokyeon
    • Tribology and Lubricants
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    • v.37 no.5
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    • pp.164-171
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    • 2021
  • Ultrasonic sensors show various reception characteristics based on the density of the measurement medium; hence, they are used in various fields to benefit from the characteristics of ultrasonic signals. In this study, the reception characteristics according to the thickness of the first matching layer are compared and analyzed for application to gas tank microleak detection. Accordingly, three types of sensors are manufactured with varying thicknesses of the first matching layer, namely 4.8 mm, 5.1 mm, and 5.5 mm; further, a direct measurement method is used wherein the sensor is attached to the inside of the chamber. Experiments are conducted to observe the phase change due to microleakage, which is the most linear in the sensor with the 4.8 mm thick first matching layer. This is assumed to be the result of stable signal transmission and reception with little phase deviations over time because the first matching layer is closest to the ultrasonic wavelength. The other sensors show nonlinear results with increasing thickness of the first matching layer. Through this study, it is found that appropriately selecting the thickness of the first matching layer of the ultrasonic sensor can greatly influence sensor reliability.

The Analysis of Wear Phenomena on Added Carbon Content Gas Atmosphere in Ion-Nitriding (이온질화에 있어서 가스중 첨가탄소량에 대한 마모현상 분석)

  • 조규식
    • Tribology and Lubricants
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    • v.13 no.2
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    • pp.96-104
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    • 1997
  • This paper was focused on the wear characteristics of ion-nitrided metal and with ion-nitride processing, which is basically concerned with the effects of carbon content in workpiece and added carbon content gas atmosphere on the best wear performance. Increased carbon content in workpiece increases compound layer thickness, but decreases diffusion layer thickness. On the other hand, a small optimal amount of carbon content in gas atmosphere increase compound layer thickness as well as diffusion layer thickness and hardness. Wear tests show that the compound layer of ion-nitrided metal reduces wear rate when the applied wear load is small. However, as the load becomes large, the existence of compound layer tends to increase wear rate. Compressive residual stress at the compound layer is the largest at the compound layer, and decreases as the depth from the surface increases. It is found in the analysis that under small applied load, the critical depth where voids and cracks may be created and propagated is located at the compound layer, so that the adhesive wear is created and the existence of compound layer reduces the amount of wear. When the load becomes large, the critical depth is located below the compound layer and delamination, which may explained by surface deformation, crack nucleation and propagation, is created and the existence of compound layer increases wear rate. For the compound layer, at added carbon contents of 0 percent and 0.5 at. percent, the ε monophase is predominant. But at 0.7 at. percent added carbon, the ε monophase formation tends to be severely inhibited and r' and Fe3C polyphase formation becomes dominant. This increased hard ε phase layer was observed to be more beneficial in reducing friction and wear.

Numerical simulation of the effect of bedding layer on the tensile failure mechanism of rock using PFC2D

  • Sarfarazi, Vahab;Haeri, Hadi;Marji, Mohammad Fatehi
    • Structural Engineering and Mechanics
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    • v.69 no.1
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    • pp.43-50
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    • 2019
  • In this research, the effect of bedding layer on the tensile failure mechanism of rocks has been investigated using PFC2D. For this purpose, firstly calibration of PFC2d was performed using Brazilian tensile strength. Secondly Brazilian test was performed on the bedding layer. Thickness of layers were 5 mm, 10 mm and 20 mm. in each thickness layer, layer angles changes from 0 to 90 with increment of 15. Totally, 21 model were simulated and tested by loading rate of 0.016 mm/s. The results show that when layer angle is less than 15, tensile cracks initiates between the layers and propagate till coalesce with model boundary. Its trace is too high. With increasing the layer angle, less layer mobilizes in failure process. Also, the failure trace is very short. It's to be noted that number of cracks decrease with increasing the layer thickness. Also, Brazilian tensile strength is minimum when bedding layer angle is between 45 and 75. The maximum one is related to layer angle of 90.

Secondary Phase and Defects in Cu2ZnSnSe4 Solar Cells with Decreasing Absorber Layer Thickness

  • Kim, Young-Ill;Son, Dae-Ho;Lee, Jaebaek;Sung, Shi-Joon;Kang, Jin-Kyu;Kim, Dae-Hwan;Yang, Kee-Jeong
    • Current Photovoltaic Research
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    • v.9 no.3
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    • pp.84-95
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    • 2021
  • The power conversion efficiency of Cu2ZnSnSe4 (CZTSe) solar cells depends on the absorber layer thickness; however, changes in the characteristics of the cells with varying absorber layer thickness are unclear. In this study, we investigated the changes in the characteristics of CZTSe solar cells for varying absorber layer thickness. Five absorber thicknesses were employed: CZTSe1 2.78 ㎛, CZTSe2 1.01 ㎛, CZTSe3 0.55 ㎛, CZTSe4 0.29 ㎛, and CZTSe5 0.15-0.23 ㎛. The efficiency of the CZTSe solar cells decreased as the absorber thickness decreased, resulting in power conversion efficiencies of 10.45% (CZTSe1), 8.67% (CZTSe2), 7.14% (CZTSe3), 3.44% (CZTSe4), and 1.54% (CZTSe5). As the thickness of the CZTSe absorber layer decreased, the electron-hole recombination at the grain boundaries and the absorber-back-contact interface increased. This caused an increase in the current loss, owing to light loss in the long-wavelength region. In addition, as the thickness of the CZTSe absorber layer decreased, more ZnSe was produced, and the resulting defects and defect clusters led to an open-circuit voltage loss.