• Title/Summary/Keyword: Scattering Analysis

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Recent Developments in High-performance Liquid Chromatography of Lipids

  • Christie, William W.
    • Journal of the Korean Applied Science and Technology
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    • v.10 no.1
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    • pp.1-8
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    • 1993
  • The possibilities for HPLC analysis of lipids have been revolutionised by the availability of evaporative light-scattering detectors, with which the response is independent of the nature of the mobile phase and does not depend On the presence of specific chromophores in the lipids. It was thus possible to develop an HPLC procedure, involving ternary gradient elution, for separating all the lipid classes in animal tissues in a single step. Although reversed-phase HPLC has been widely used for the analysis of molecular species of lipids, sliver ion chromatography can be a valuable alternative. For example, a stable silver ion column for HPLC was developed which permitted resolution of molecular species of triacylglycerols, even from such complex samples as fish oils, again With light-scattering detection and gradient elution. The capacity for HPLC resolution of diastereomeric diacyl-sn-glycerol derivatives, prepared from triacylglycerols. has lead to a new simple method for stereospecific analysis of the latter.

Electromagnetic Interference Analysis of an Inhomogeneous Electromagnetic Bandgap Power Bus for High-Speed Circuits

  • Cho, Jonghyun;Kim, Myunghoi
    • Journal of information and communication convergence engineering
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    • v.15 no.4
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    • pp.237-243
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    • 2017
  • This paper presents an analysis of the electromagnetic interference of a heterogeneous power bus where electromagnetic bandgap (EBG) cells are irregularly arranged. To mitigate electrical-noise coupling between high-speed circuits, the EBG structure is placed between parallel plate waveguide (PPW)-based power buses on which the noise source and victim circuits are mounted. We examine a noise suppression characteristic of the heterogeneous power bus in terms of scattering parameters. The characteristics of the dispersion and scattering parameters are compared in the sensitivity analysis of the EBG structure. Electric field distributions at significant frequencies are thoroughly examined using electromagnetic simulation based on a finite element method (FEM). The noise suppression characteristics of the heterogeneous power bus are demonstrated experimentally. The heterogeneous power bus achieves significant reduction of electrical-noise coupling compared to the homogeneous power buses that are adopted in conventional high-speed circuit design. In addition, the measurements show good agreement with the FEM simulation results.

An Investigation of Methanol and Methanol Blended Sprays Using Laser Scattering Images

  • Park, Wook;Park, Byung-Chul
    • Journal of Mechanical Science and Technology
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    • v.15 no.12
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    • pp.1699-1710
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    • 2001
  • The characteristics of methanol and methanol blended (M85) sprays were investigated under atmospheric conditions at various temperature, ranging from on-vaporizing to vaporizing ambient conditions (298∼353 K). From laser scattering images, the macroscopic characteristics of the spray, such as the spray tip penetration and the spray angle, were determined. Entropy concept was introduced to represent homogeneity and PIV analysis was adopted to determine the fluid dynamic information at each location of the spray. The correlation between entropy and vorticity strength enabled us to find their relations. The effect of ambient composition, mainly of viscous effect as affected by CO$_2$levels, was investigated using PIV and entropy analysis. Spray width and entropy value were found to tend to decrease at increased CO$_2$levels.

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Label-free NanoBio Imaging for New Biology and Medical Science

  • Moon, Dae Won
    • Applied Science and Convergence Technology
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    • v.24 no.6
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    • pp.203-214
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    • 2015
  • We have been developing a new label-free nanobio imaging platform using non-linear optics such as Coherent Anti-Stokes Raman Spectroscopy (CARS) and ion beam techniques based on sputtering and scattering such as Secondary Ion Mass Spectrometry (SIMS) and Medium Energy Ion Scattering Spectroscopy (MEIS), which have been widely used for atomic and molecular level analysis of semiconductors and nanomaterials. To apply techniques developed for semiconductors and nanomaterials for biomedical applications, the convergence of nano-analysis and biology were tried. Our activities on label-free nanobio imaging during the last decade are summarized in this review about non-linear optical 3D imaging, ellipsometric interface imaging, SIMS imaging, and TOF-MEIS nano analysis for cardiovascular tissues, collagen thin films, peptides on microarray, nanoparticles, and cell adhesion studies and finally the present snapshot of nanobio imaging and the future prospect are described.

Chemical Composition of Fine Aerosol Associated with Visibility Degradation in Seoul Metropolitan Area in 1994 (1994년 수도권 지역에서의 시정과 미세 입자상물질 화학조성과의 관계해석)

  • 한진석;김병곤;김신도
    • Journal of Korean Society for Atmospheric Environment
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    • v.12 no.4
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    • pp.377-387
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    • 1996
  • This study was carried out to monitor the visibility including measurement and analysis of the various parameters such as particle size distribution, chemical composition, and meteorotical conditions to understand the characteristics and causes of this phenomenon. According to the analysis of intensive sampling, $SO_4^{2-}, NO-3^-, Cl^-, NH_4^+$ ion concentration increased together with the mass concentration around 1 $\mu$m in the case of low visibility. $(NH_4)_2SO_4, NH_4NO_3$, and $NH_4Cl$ were thought to be the major components of fine particles. The statistical analysis showed that the scattering effect of particle was 81.2%, the absorption effect was 14.9%. Therefore, these effects were the major factors to reduce the visibility. In conclusion, the visibility was reduced by the fine particle of sulfate (18.6%), nitrate (14.2%), organic carbon (10.8%), element carbon (25.8%), and residual (24.8%) during this study.

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Analysis of E-polarized Electromagnetic Scattering by a Conductive Strip Grating Between a Double Dielectric Layer Using FGMM (FGMM을 이용한 2중 유전체층 사이의 완전도체띠 격자구조에 의한 E-분극 전자파 산란 해석)

  • Yoon, Uei-Joong
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.1
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    • pp.77-82
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    • 2020
  • In this paper, E-polarized electromagnetic scattering problems by a conductive strip grating between a double dielectric layer are analyzed by applying the FGMM(Fourier-Galerkin moment method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, and the conductive boundary condition is applied to analysis of the conductive strip. The numerical results for the normalized reflected and transmitted power are analyzed by according as the width and spacing of conductive strip, the relative permittivity and thickness of the double dielectric layers, and incident angles. Generally, as the value of the dielectric constant of the double dielectric layer increases, the reflected power increases and the transmitted power decreases, respectively. As the dielectric constant of the double dielectric layer increases, the current density induced in the strip center increases. The numerical results for the presented structure of this paper are shown in good agreement compared to those of the existing papers.