• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.51-51
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• 2002

나노기공물질은 특정 기반물질(matrix) 내부에 대략 나노미터크기의 기공을 함유하고 있는 물질이며 나노기공물질의 특성은 기반물질의 특성과 더불어 기공의 형태, 크기, 분포에 의해서 결정된다. 나노기공물질의 기공에 대한 정보를 측정하는 방법으로는 TEM, 흡착법, FE-SEM과 더불어 중성자 또는 X-ray 빔의 산란을 이용하는 소각중성자산란 (Small-Angle Neutron Scatering, SANS), 소각 X-ray 산란 (Small-Angle X-ray Scattering, SAXS), 중성자반사율측정 (Neutron Relfectimetry, NR), X-ray 반사율측정 (X-Ray Reflectometry, XRR) 등이 사용되고 있다. 본 발표는 대략 1 nm - 100 nm 영역의 bulk 구조와 층상구조를 측정할 수 있는 소각 중성자 산란과 중성자 반사율 측정기법을 이용한 나노기공 측정기술을 다룬다.

• Current Optics and Photonics
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• v.5 no.6
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• pp.597-605
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• 2021

An extended Fourier modal method (FMM) for optical dipole radiation in three-dimensional photonic structures is proposed. The core elements of the proposed FMM are the stable bidirectional scattering-matrix algorithm for modeling internal optical emission, and a novel optical-dipole-source model that prevents numerical errors induced by the Gibbs phenomenon. Through the proposed scheme, the FMM is extended to model a wide range of source-embedded photonic structures.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.89-114
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• 1996

Liquid crystal-polymer composite(LCPC) films consisting of a continuous LC phase embedded in a three-dimensional network of polymer matrix are formed by photopolymerization-induced phase separ on. The LCPC films are switched from a light-scattering stats to a highly transparent stats on the application of electric fields. Since the alignment of LC molecular determines the electro-optical properties of films, the requirement for good contrast is to generate the nematic phase at high concentration. On the other hand, the concentration of UV-curable monomer must be increased above some critical value to from the flexible matrix of unbounded polymer. The mixing ratio of LC and UV-curable monomer affects the electro-optical and viscoelastic properties of LCPD films in two opposing ways. By controlling the phase separation process, at an LC fraction of 0.7, the maximum performance of LCPC films has been achieved, the response time of which is 2ms on the application of electric fields.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.5
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• pp.16-22
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• 1983

Liquid crystal matrix display is fabricated. ITO transparent electrode and silver paste metal electrode are coated on glad substrate using silk screen printing technique, and SiO is coated on the transparent electrode by evaporation. Liquid crystal molecules are aligled by rubbing technique and displays of Alphanumeric and Hangul are tried using the dynamic scattering effect and the 3: 1 selection method.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.79-83
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• 2003

Multi-port($2{\times}2$port, 1port) rectangular waveguide discontinuity problem has been analyzed by use of $TE^x_{mn}$ (mono)mode matching method. Matrix size can be reduced significantly in comparison with $TE_{mn}&TM_{mn}$(full-wave)mode matching method. the present results is compared with those by CST MicroWave Studio to validate the presint method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.270-277
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• 2006

Inverse radiation problems were solved for estimating boundary temperature distribution in a way of function estimation approach in an axisymmetric absorbing, emitting and scattering medium, given the measured radiative data. In order to reduce the computational time fur the calculation of sensitivity matrix, automatic differentiation and Broyden combined method were adopted, and their computational precision and efficiency were compared with the result obtained by finite difference approximation.. In inverse analysis, the effects of the precision of sensitivity matrix, the number of measurement points and measurement error on the estimation accuracy had been inspected using quasi-Newton method as an inverse method. Inverse solutions were validated with the result acquired by additional inverse methods of conjugate-gradient method or Levenberg-Marquardt method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.3
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• pp.273-288
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• 1997

In this work, the electromagnetic waves scattered from 2-dimensional random rough surfaces are characterized by the $4\times4$ Mueller matrix elements. The full wave solutions are used to compute these elements. The results of the full wave solutions for 1-dimensional random rough surfaces were shown to agree well with those of the experiment and the method of moments. The Mueller matrix elements are related to the like and cross polarized radar cross sections as well as to the relative phase of the vertically and horizontally polarized waves. The $4\times4$ Mueller matrix elements completely characterize electromagnetic scattering from target. The computed results of this paper can be useful to the field of active remote sensing or RCS.

• Archives of Pharmacal Research
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• v.26 no.2
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• pp.173-181
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• 2003

A polymeric micelle drug delivery system was developed to enhance the solubility of poorly-water soluble drug, biphenyl dimethyl dicarboxylate, DDB. The block copolymers consisting of poly(D,L-lactide) (PLA) as the hydrophobic segment and methoxy poly(ethylene glycol) (mPEG) as the hydrophilic segment were synthesized and characterized by NMR, DSC and MALDI-TOF mass spectroscopy. The size of the polymeric micelles measured by dynamic light scattering showed a narrow monodisperse size distribution with the average diameter less than 50 nm. The MW of mPEG-PLA, 3000 (MW of mPEG, 2 K; MW of PLA, 1K), and the presence of hydrophilic and hydrophobic segments on the polymeric micelles were confirmed by MALDI-TOF mass spectroscopy and NMR, respectively. Polymeric micelle solutions of DDB were prepared by three different methods, i.e. the matrix method, emulsion method and dialysis method. In the matrix method, DDB solubility was reached to 13.29 mg/mL. The mPEG-PLA 2K-1K micelle system was compared with the poloxamer 407 micelle system for their critical micelle concentration, micelle size, solubilizing capacity, stability in dilution and physical state. DDB loaded-polymeric micelles prepared by the matrix method showed a significantly increased aqueous solubility (＞5000 fold over intrinsic solubility) and were found to be superior to the poloxamer 407 micelles as a drug carrier.

• Polymer(Korea)
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• v.34 no.5
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• pp.415-423
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• 2010

Poly(vinyl alcohol)(PVA) with high degree of hydrolysis of above 98% was dissolved in dimethyl sulfoxide(DMSO), and the shear viscosity was measured up to $C{\simeq}0.14\;g/mL$ in the semi-dilute solution regime. Next, as probe particle, polystyrene(PS) latex was introduced into this matrix system and its delayed diffusion due to polymer concentration was investigated by means of dynamic light scattering. When the solution viscosity of PVA/DMSO was plotted against the reduced concentration $C[{\eta}]$, which is scaled by the intrinsic viscosity, the molecular weight dependence was strongly appeared at C$[{\eta}]$ >2. Some heterogeneties in polymer solution were considered as its source. Contrary, the diffusion of probe particle in the matrix solution was observed as a single mode motion at whole concentration range but its ratio of its diffusion coefficient at solution to that at solvent, D/Do did not show any molecular weight dependence at all. However, the application limit of the stretched exponential function was disclosed at C$[{\eta}]$ >2.5.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.156-163
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• 2013

In this paper, we propose an algorithm for estimating media characteristics of sea water and subbottom multi-layers. The proposed algorithm for estimating reflection coefficients, uses a transmitted signal and reflected signal obtained from multiple layers of various shape and structure, and the algorithm is called Schur algorithm. The algorithm is efficient in estimating the reflection coefficients since it finds solution by converting the given inverse scattering problem into matrix factorization. To verify the proposed algorithm, we generate a transmit signal and reflected signal obtained from lattice filter model for sea water and subbottom of multi-level non-homogeneous layers, and then find that the proposed algorithm can estimate reflection coefficients efficiently.