• Korean Journal of Optics and Photonics
• /
• v.24 no.5
• /
• pp.279-286
• /
• 2013

Brillouin spectroscopy has been widely used for the investigation of acoustic properties of condensed matters in the hypersonic region. A high-pressure Brillouin spectrometer was set up by combining a diamond anvil cell and a tandem multi-pass Fabry-Perot interferometer. It was successfully applied to liquid ethanol, and the pressure dependence of the sound velocity, the refractive index and other acoustic properties were derived based on the measurements. The detailed optical setup and experimental procedure are described.

• Journal of Korean Society of Archives and Records Management
• /
• v.12 no.2
• /
• pp.7-27
• /
• 2012

The purpose of this study is to investigate interdisciplinary changes in the field of Archives and Records Management in Korea. For this purpose, this study analyzed disciplinary attributes of citing and cited references appeared in the Journal of the Korean Society of Archives and Records Management during the period, 2001-2011. One hundred and ninty five research articles and two thousands nine hundreds ninty seven cited references were analyzed to find the degree of interdisciplinarity by using direct citation and Brillouin index. Finally, the interdisciplinary changes of source literature and cited references in Korean archival science during the period were suggested.

• Journal of Information Display
• /
• v.10 no.2
• /
• pp.72-75
• /
• 2009

The Brillouin spectrum of 4'-n-pentyl-4-cyano-biphenyl (5CB) liquid crystals homogeneously confined in a planar liquid crystal (LC) cell was measured using a 6-pass tandem Fabry-Perot interferometer. By adopting a special right-angle scattering geometry, the sound velocity of 5CB was estimated from the Brillouin shift without knowing the refractive index. The sound velocity of the longitudinal wave propagating along the direction of the directors aligned parallel to the glass plates of the LC cell was 1784${\pm}$7 m/s at 300 K. The attenuation coefficient $\alpha$ was estimated to be approximately $1.9{\times}10^6m^{-1}$, which is about twice as large as that of the longitudinal sound wave propagating along the direction perpendicular to the directors. The present method may be very useful in the evaluation of the elastic properties of the materials used in display devices, whose refractive indices are not known.

• Korean Journal of Optics and Photonics
• /
• v.17 no.6
• /
• pp.493-499
• /
• 2006

Arbitrary graded-index HOF(Hollow Optical Fibers) are analyzed using the modified Airy function, and the corresponding eigenvalue equation that renders precise results is derived. For graded index HOF, the gradient of an evanescent field in hollow region could be adjusted more sharply than the conventional step-index HOF and the feasibility of more effective atom-guiding is confirmed.

• Journal of the Korean Society for information Management
• /
• v.13 no.1
• /
• pp.205-226
• /
• 1996

Under the hypothesis that any pair of terms in the sentence is meaningful to present the context of the paper, the Brillouin measure of term relatedness in automatic indexing is proposed. For the experiment, the pair of terms simul-taneously appeared in two or more sentences of the paper are extracted from the title and abstract of the paper. Com-pared with the list of index terms or subject headings suggested by the author, the terms in term relatedness graph are highly matched with the terms in the list. Especially, it is revealed that the rank of terms by synthetic strength is use-ful in the selection of index terms.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.9
• /
• pp.919-925
• /
• 2011

In this paper, we designed and analyzed a 3D isotropic bulk structure consisting of thin wires and SRR's(Split Ring Resonator) with which the permittivity and permeability can be controlled at the same time. For the 3D isotropic bulk structure, first of all, the geometry seen by three main axes must look alike. Thus, we adopted the orthogonal thin wires and symmetrical SRR's. As a result, we constructed metamaterial bulk structures of which effective relative permittivity and permiability are about -0.6 and -1.5, respectively. Its refractive index is about -0.95 in each direction(x, y and z direction). The computed Brillouin dispersion diagram also showed that the proposed structure is almost near isotropic.

• Korean Journal of Optics and Photonics
• /
• v.13 no.6
• /
• pp.473-478
• /
• 2002

Circular slab waveguides are conformally mapped into straight waveguides. In the outer cladding region with monotonically increasing index profile, modified Airy functions (MAF) of traveling-wave form are introduced to express the leaky mode. Field distributions and losses calculated by the proposed method are compared with those obtained by the WKB (Wentzel-Kramers-Brillouin) method. Detailed numerical examples are presented and compared with the conventional WKB methods, demonstrating our method not only allows a converging field at turning points but also guarantees fine accuracy.