• Title/Summary/Keyword: Fraunhofer

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Laser Illuminated Multi-viewer 3D Displays

  • Sexton, Ian;Bates, Richard;Lee, Wing;Surman, Phil;Hopf, Klaus;Neumann, Frank;Corbett, Alex;Buckley, Edward
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1423-1426
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    • 2008
  • This paper describes current work regarding two EC funded projects, MUTED and HELIUM3D whose objective is to produce an autostereoscopic display system which is well suited to domestic television applications. Both of these projects have common roots in a previous EC funded project (ATTEST) and both employ laser illumination and viewer head tracking.

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Measuring System of Surface Roughness for On-The-Machine using Diffraction Light (회절광을 이용한 기상계측용 표면거칠기의 측정시스템)

  • 김성훈;이기용;강명창;김정석;김남경
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.803-807
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    • 2000
  • This paper deals wi th the establishment of the method of non-contact surface roughness measurement by developed system. One of the most Important factor of determinating quality of a produced manufacture is surface roughness The tendency of manufacturing method is changing from small amount manufactures / high-volume production to large amount manufactures / low volume production, and the study of reducing time for surface roughness measurement has been actively investigated The non-contact surface roughness method by using laser which is different from contact method has been only used to the polished surface, so new surface roughness measurement method was adopted by virtue of Fraunhofer diffraction in the periodic surface for on-the-machine. in this paper, we establish the method of non-contact surface roughness measurement which can reduce measuring time in the periodic surface

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A Diffraction Transfer Function Approach to the Calculation of the Transient Field of Acoustic Radiators

  • Lee, Chan-Kil
    • ETRI Journal
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    • v.16 no.1
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    • pp.1-15
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    • 1994
  • A computationally-efficient approach to the calculation of the transient field of an acoustic radiator was developed. With this approach, a planar or curved source, radiating either continuous or pulsed waves, is divided into a finite number of shifted and/or rotated versions of an incremental source such that the Fraunhofer approximation holds at each field point. The acoustic field from the incremental source is given by a 2-D spatial Fourier transform. The diffraction transfer function of the entire source can be expressed as a sum of Fraunhofer diffraction pattern of the incremental sources with the appropriate coordinate transformations for the particular geometry of the radiator. For a given spectrum of radiator velocity, the transient field can be computed directly in the frequency domain using the diffraction transfer function. To determine the accuracy of the proposed approach, the impulse response was derived using the inverse Fourier transform. The results obtained agree well with published data obtained using the impulse response approach. The computational efficiency of the proposed method compares favorably to those of the point source method and the impulse response approach.

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Optical Design of Cemented Doublets by Using Equivalent Lens System (등가렌즈를 이용한 2매 접합렌즈계의 설계)

  • 전영세;김형수;이종웅;박성찬
    • Korean Journal of Optics and Photonics
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    • v.9 no.5
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    • pp.282-290
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    • 1998
  • The equivalent lens conversion technique is applied to design achromatic doublet and aplanatic doublet. A thin doublet which has zero axial thicknesses, are corrected for the third order aberrations at first, and the thin doublet is converted into thick lens system by using the equivalent lens conversion. Two types of cemented doublets, the Fraunhofer type and the Steinheil type, are designed by using a crown glass BaK-2 and a flint glass SF-2. In the thin doublet design, there are two achromatic solutions and a aplanatic solution for the both types.

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Carbon-Nanofiber Reinforced Cu Composites Prepared by Powder Metallurgy

  • Weidmueller, H.;Weissgaerber, T.;Hutsch, T.;Huenert, R.;Schmitt, T.;Mauthner, K.;Schulz-Harder, S.
    • Journal of Powder Materials
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    • v.13 no.5 s.58
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    • pp.321-326
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    • 2006
  • Electronic packaging involves interconnecting, powering, protecting, and cooling of semiconductor circuits fur the use in a variety of microelectronic applications. For microelectronic circuits, the main type of failure is thermal fatigue, owing to the different thermal expansion coefficients of semiconductor chips and packaging materials. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers. The advantages of carbon nanofibers, especially the good thermal conductivity, are utlized to obtain a composite material having a thermal conductivity higher than 400 W/mK. The main challenge is to obtain a homogeneous dispersion of carbon nanofibers in copper. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed. In order to improve the bonding strength between copper and nanofibers, different alloying elements were added. The microstructure and the properties will be presented and the influence of interface modification will be discussed.

Effects of Dietary Protein and Threonine Supply on In vitro Liver Threonine Dehydrogenase Activity and Threonine Efficiency in Rat and Chicken

  • Lee, C.W.;Oh, Y.J.;Son, Y.S.;An, W.G.
    • Asian-Australasian Journal of Animal Sciences
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    • v.24 no.10
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    • pp.1417-1424
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    • 2011
  • This study was conducted to assess the relation between threonine (Thr) oxidation rate and threonine efficiency on rat and chicken fed with graded levels of protein and threonine. The increase in threonine content from 0.28 to 0.72% in a diet containing 12.0% crude protein (CP) caused a gradual increase in threonine dehydrogenase (TDG) activity in rat liver. Similar, but more pronounced results were observed after 18.0% CP in the diet. Both protein levels in combination with the highest level of threonine supplementation increased liver TDG activity significantly, indicating enhanced threonine catabolism. Parameters of efficiency of threonine utilization calculated from parallel nitrogen balance studies decreased significantly and indicated threonine oversupply after a maximum of threonine supplementation. At the lower levels of threonine addition the efficiency of threonine utilization was not significantly changed. In the chicken liver up to 0.60% true digestible threonine (dThr) in the 18.5% CP diet produced no effect on the TDG activity. However, TDG activity in the liver was elevated by the diet containing 22.5% CP (0.60% dThr) and the efficiency of threonine utilization decreased, indicating the end of threonine limiting range. In conclusion, the in vitro TDG activity in the liver of rat and growing chicken has an indicator function for the dietary supply of threonine.

Novel Anti-Angiogenic Activity in Rubus coreanus Miquel Water Extract Suppresses VEGF-Induced Angiogenesis

  • Kim, Eok-Cheon;Kim, Hye Jin;Kim, Tack-Joong
    • Biomedical Science Letters
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    • v.20 no.4
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    • pp.209-220
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    • 2014
  • Vascular endothelial growth factor (VEGF) is a key factor involved in the induction of angiogenesis and has become an attractive target for anti-angiogenesis therapies. The purpose of this study was to elucidate the anti-angiogenic activity of Rubus coreanus Miquel water extract (RCME). Rubus coreanus Miquel has long been employed as a traditional medicine, and recent studies have demonstrated that it has measureable biological activities. Thus, we investigated for the first time the effect of RCME on angiogenesis and its underlying signaling pathways. The effects of RCME were tested on in vitro models of angiogenesis, namely, proliferation, migration, invasion and tube formation of human umbilical vein endothelial cells as well as an ex vivo model of vessel sprouting from the rat aorta in response to VEGF. We observed that VEGF-induced angiogenesis was strongly suppressed by RCME treatment compared to that of the control group. Moreover, we found that RCME inhibited VEGF-induced activation of matrix metalloproteinases and phosphorylation of extracellular signal-regulated kinase and p38, and also effectively inhibited phosphorylation of VEGF receptor 2. These results indicated that RCME inhibits angiogenesis by suppressing phosphorylation of the VEGF receptor and may be useful for the treatment of angiogenesis-dependent diseases such as cancer and diabetic retinopathy.