• Title, Summary, Keyword: Thickness

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Fast Analysis of Film Thickness in Spectroscopic Reflectometry using Direct Phase Extraction

  • Kim, Kwangrak;Kwon, Soonyang;Pahk, Heui Jae
    • Current Optics and Photonics
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    • v.1 no.1
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    • pp.29-33
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    • 2017
  • A method for analysis of thin film thickness in spectroscopic reflectometry is proposed. In spectroscopic reflectometry, there has been a trade-off between accuracy and computation speed using the conventional analysis algorithms. The trade-off originated from the nonlinearity of spectral reflectance with respect to film thickness. In this paper, the spectral phase is extracted from spectral reflectance, and the thickness of the film can be calculated by linear equations. By using the proposed method, film thickness can be measured very fast with high accuracy. The simulation result shows that the film thickness can be acquired with high accuracy. In the simulation, analysis error is lower than 0.01% in the thickness range from 100 nm to 4 um. The experiments also show good accuracy. Maximum error is under $40{\AA}$ in the thickness range $3,000-20,000{\AA}$. The experiments present that the proposed method is very fast. It takes only 2.6 s for volumetric thickness analysis of 640*480 pixels. The study suggests that the method can be a useful tool for the volumetric thickness measurement in display and semiconductor industries.

Diagnosis of Thickness Quality Using Multivariate Statistical Analysis in Hot Finishing Mill

  • Kim, Heung-Mook
    • 제어로봇시스템학회:학술대회논문집
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    • pp.116.3-116
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    • 2001
  • A diagnosis methodology for thickness quality in hot finishing mill is proposed based on multivariate statistical analysis. The thickness of hot strip is a key quality factor that is measured by x-ray thickness gauge. Currently, the thickness quality is guaranteed by upper and lower limit of thickness deviation from target thickness. But if any over-limit is occurred, there is no in-line method to identify the causes. In this paper, many parameters are extracted from the thickness deviation signal such as mean deviation(top, middle, tail), rms deviation(top, middle, tail) and peak deviation(top, middle, tail) as time domain parameters ...

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Color soft contact lens and corneal thickness

  • Kim, Douk-Hoon
    • Journal of Korean Clinical Health Science
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    • v.7 no.1
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    • pp.1205-1214
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    • 2019
  • Purpose: To investigate the effect of color soft contact lenses on the corneal thickness in young Korean population. Methods: The subjects consisted of 112 eyes (7 males, 49 females) with the mean age of $20.987{\pm}1.093years$ (range 20-25 years) in young Korean population during 2018. Test was compared the corneal thickness before and after wearing color soft contact lenses. The thinnest cornea thickness(TCT), central cornea thickness(CCT), pupil centre thickness(PCT), superior corneal thickness(SCT),inferior corneal thickness(ICT), medial corneal thickness(MCT), lateral corneal thickness(LCT) of the cornea was measured using the Pentacam pachymetry. The statistically analysis was perform the Shaparo-Wilk test. Results: The right eye was a statistically significant among the CCT,LCT, MCT and TCT values(p<0.001) in the compared the corneal thickness before and after wearing soft colour contact lenses. Also the left eye was a statistically significant among the LCT and MCT values(p<0.001) in the compared the corneal thickness before and after wearing soft colour contact lenses. However, there was no statistical difference (p>0.5) in the mean PCT between before and after wearing color soft contact lenses. Conclusion: These results suggested that the color soft contact lens wear can the effect the regional thickness of cornea. Therefore, the analysis of corneal topography with Pentacam can provide correct and useful diagnostic information of the morphology of the RGP contact lens fitting and diagnosis of corneal refraction surgery.

Prediction of Laminar Burning Velocity and Flame Thickness in Methane-Air Pre-Mixture (메탄-공기 예혼합기에서의 층류 화염속도 및 화염두께 예측)

  • Kwon, Soon-Ik;Bowen, Philip J.
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.9
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    • pp.1201-1208
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    • 2003
  • The thickness of flame and preheat zone from burning velocity which was computed by using Premix code of Chemkin program for methane-air mixture. Also the thickness was evaluated from temperature profile which is also obtained from Premix code for the equivalence ratio of 0.5 to 1.6. The computations were carried out for the laminar flame thickness and burning velocity under the unburned gas temperature 0.5bat-30bar and temperature of 300K-700K at ${\Phi}=l.0$. Comparison of the results showed no difference between these two methods. The flame thickness was decreased by increasing the pressure and temperature, but, the affect of pressure is more significant than the effect of temperature on the flame thickness. The thickness of preheat zone was about 66.5% of the flame thickness, and flame thickness and burning velocity were also predicted by using empirical equation.

Study on Thin Sea Ice Thickness using Passive Microwave Brightness Temperature

  • Naoki, Kazuhiro;Ukita, Jinro;Nishio, Fumihiko
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.1015-1018
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    • 2006
  • The use of passive microwave data for estimating sea-ice thickness is limited by strong dependence of emissivity on near-surface brine. However, this particular characteristic becomes a basis for an algorithm to estimate thickness of thin sea-ice if a thickness-salinity-emissivity relationship is established. This study aims at developing an algorithm to estimate sea ice thickness on the basis of this relationship. In order to establish a thickness-salinity-emissivity relationship, we have conducted multi-platform synchronous observations in the Sea of Okhotsk. We note a positive relationship between thickness and brightness temperature. From observations, we also establish an empirical relationship between salinity and emissivity, thus between thickness and brightness temperature. The derived relationship is qualitatively similar to the one based on Hoekstra and Cappillino's formulation. Our results suggest that for thin sea-ice in the winter period there is potential to develop an algorithm to estimate sea-ice thickness.

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Studies on Thickness of Eggshell and Eggshell Membrane of Korean Native Chicken (한국 재래닭의 난각 및 난각막의 두께에 관한 연구)

  • 하정기;박준규;이정규
    • Korean Journal of Poultry Science
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    • v.24 no.1
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    • pp.29-37
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    • 1997
  • An experiment was conducted for 20 days( from July 21 to August 10, 1996) to investigate the differences in thickness of eggshell and eggshell membrane in Korean native chicken. All the eggs were purchased from a farm located in Chinju area. All eggs were categorized into Treatment I (34.89~51.39 g), H (53.32~60.70 g), and III (34.89~60.70 g) according to their weights. Eleven items were measured in all three treatments, i.e., egg weight, egg length, egg width, breaking strength, eggshell thickness of large end(STLE), eggshell membrane thickness of large end(SMTL), eggshell thickness of small end (STSE), eggshell membrane thickness of small end(SMTS), eggshell thickness of middle part(STMP), and eggshell membrane thickness of middle part(SMTM). Correlation coefficients between egg weight and eggshell weight, among eggshell thickness of large end, small end and middle end and eggshell weight were significant (P<0.01). Correlation coefficients between egg weight and large eggshell membrane were nega-tively significant(P<0.01). Breaking strengths were higher in Treatment I than in Treatment H. Correlation coefficients among thickness of eggshell and eggshell membrane at each point at 3 parts of large end, small end and middle end were not significant.

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Reaction Zone Thickness of Turbulent Premixed Flame

  • Yamamoto, Kazuhiro;Nishizawa, Yasuki;Onuma, Yoshiaki
    • Journal of the Korean Society of Combustion
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    • v.6 no.2
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    • pp.36-42
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    • 2001
  • Usually, we use the flame thickness and turbulence scale to classify the flame structure on a phase diagram of turbulent combustion. The flame structure in turbulence is still in debate, and many studies have been done. Since the flame motion is rapid and its reaction zone thickness is very thin, it is difficult to estimate the flame thickness. Here, we propose a new approach to determine the reaction zone thickness based on ion current signals obtained by an electrostatic probe, which has enough time and space resolution to detect flame fluctuation. Since the signal depends on the flow condition and flame curvature, it may be difficult to analyze directly these signals and examine the flame characteristics. However, ion concentration is high only in the region where hydrocarbon-oxygen reactions occur, and we can specify the reaction zone. Based on the reaction zone existing, we estimate the reaction zone thickness. We obtain the thickness of flames both in the cyclone-jet combustor and on a Bunsen burner, compared with theoretically predicted value, the Zeldovich thickness. Results show that the experimentally obtained thickness is almost the same as the Zeldovich thickness. It is concluded that this approach can be used to obtain the local flame structure for modeling turbulent combustion.

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Voxel-Based Thickness Analysis of Intricate Objects

  • Subburaj, K.;Patil, Sandeep;Ravi, B.
    • International Journal of CAD/CAM
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    • v.6 no.1
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    • pp.105-115
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    • 2006
  • Thickness is a commonly used parameter in product design and manufacture. Its intuitive definition as the smallest dimension of a cross-section or the minimum distance between two opposite surfaces is ambiguous for intricate solids, and there is very little reported work in automatic computation of thickness. We present three generic definitions of thickness: interior thickness of points inside an object, exterior thickness for points on the object surface, and radiographic thickness along a view direction. Methods for computing and displaying the respective thickness values are also presented. The internal thickness distribution is obtained by peeling or successive skin removal, eventually revealing the object skeleton (similar to medial axis transformation). Another method involves radiographic scanning along a viewing direction, with minimum, maximum and total thickness options, displayed on the surface of the object. The algorithms have been implemented using an efficient voxel based representation that can handle up to one billion voxels (1000 per axis), coupled with a near-real time display scheme that uses a look-up table based on voxel neighborhood configurations. Three different types of intricate objects: industrial (press cylinder casting), sculpture (Ganesha idol), and medical (pelvic bone) were used for successfully testing the algorithms. The results are found to be useful for early evaluation of manufacturability and other lifecycle considerations.

Experimental Identification of the Thickness Dynamics in Friction Spinning (마찰 정방에서 굵기 동역학의 실험적 확인)

  • Lim, Jung-H.;Kim, Jong-S.;Huh, You
    • Textile Science and Engineering
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    • v.48 no.5
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    • pp.322-329
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    • 2011
  • Dynamics of the bundle thickness in a friction yarn formation process was ascertained experimentally from the view point of the thickness of in-process bundle and output bundle. By changing the thickness of input fleece the thickness distribution of the in-process bundle on the friction drum and the irregularity of the output bundle in a steady state were measured. The experimental results were then compared with the simulation results derived on the basis of the dynamic model, while a step signal and a sinusoidal signal were applied. Experimental results turned out to be in a good agreement with the simulation result, which indicates that the theoretical model describes the dynamics of the frictional bundling process very good. The cross-sectional area of the in-process bundle increased linearly to the drum position in response to a step change in the input fleece thickness, which indicates that the friction bundling process can be though of as an integrating system with an interval. The periodic change in the input fleece thickness yielded also a good correspondence of the experimental results with those from the simulation. However, the thickness behavior of the output friction yarn for the periodic change in input fleece thickness demonstrated the dependency on the take-up speed of the output bundle.

An Experimental Study on the Properties of Porous Concrete according to Correction Factor and Specimen Thickness (보정계수 및 시험체두께가 포러스콘크리트의 기초물성에 미치는 영향에 관한 실험적 연구)

  • 김재환;이성일;장종호;오시덕;박정호;김무한
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.55-58
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    • 2002
  • This study is to analyze the influence of correction factor and specimen thickness on the fundamental properties of porous concrete. Results of this study were shown as follows; 1) As correction factor decrease, compaction time according to correction factor and specimen thickness decrease. Also, though correction factor is same, as specimen thickness increase, compaction time increase. So It mutt be considered that the influence of compaction time according to correction factor and specimen thickness. 2) As correction factor decrease, difference of measured thickness and designed thickness according to correction factor and specimen thickness decrease. Also, correction factor of aggregate of 10~l5mm is smaller than that of 5~l0mm. So It must be considered that the influence of correction factor according to size of aggregate.

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