• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.52.2-52.2
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• 2011

The correlation between black hole mass and galaxy stellar velocity dispersion gives an important clue on the black hole growth and galaxy evolution. In the case of AGN, however, it is extremely difficult to measure stellar velocity dispersions in the optical spectra since AGN continuum dilutes stellar absorption features. In contrast, stellar velocity dispersions of active galaxies can be measured in the near-IR, where AGN-to-star flux ratio is much smaller, particularly with the laser-guide-star adaptive optics. However, it is crucial to test whether the stellar velocity dispersion measured from the near-IR spectra is consistent with that measured from the optical spectra. Using the TripleSpec at the Palomar 5-m Telescope, we obtained high quality spectra ranging from 1 to 2.4 micron for a sample of 35 nearby galaxies, for which dynamical black hole masses and optical stellar velocity dispersion measurements are available, in order to calibrate the stellar velocity dispersion in the near-IR. In this poster, we present the initial results based on 10 galaxies, with the stellar velocity dispersion measured in the H-band.

• The Korean Journal of Rheology
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• v.10 no.1
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• pp.1-6
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• 1998

액체와 액체를 교반할 경우 혹은 두가지 이상의 상이 함께 반응하는 화학공정의 경 우에서는 비상용성인 액체들을 난류조건하에 분산시켜 섞이게 한다. 부산계로 구성된 중합 반응기의 경우 분산입자의 크기는 최종제품의 생산성 및 품질에 큰 영향을 미치게 되므로 분산입자의 크기를 예측하는 것은 대단히 중요하다. 이러한 분산계에서 분산입자의 크기는 분산입자가 겪는 유동장에 의해 결정된다. 오일/오일 분산계로 이루어진 고분자 유탁액의 난류교반시 유동장은 종종 점성전단 부영역에 속하게 되는데 이경우의 분산입자의 크기를 예측하는 모델에 대한 연구는 별로 이루어지지않았다. 본연구에서는 오일/오일 분산계의 고 분자 유탁액에 대한 분산입자의 크기를 예측하는 모델식을 유체동력학적인 이론을 배경으로 하여 개발하였다. 개발한 모델식을 난류교반을 겪은 오일/오일 분산계를 거쳐 생산된 제품 인 내충격성 폴리스티렌으로 검증하여 모델식의 타당성을 입증하였다.

• Journal of the Optical Society of Korea
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• v.7 no.1
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• pp.38-41
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• 2003

We present an analysis of highly-dispersive guided modes of two-dimensional photonic crystal waveguides. By the plane ave expansion method, band structures and mode profiles of two-dimensional photonic crystal waveguides are obtained. It is found that guided modes have very small group velocities and very large group velocity dispersions in the region near the f-point and in the region near the Brillouin zone edge. Especially, the group velocity dispersions are found to be millions of times larger than that of a conventional optical fiber. The contributions of the transverse resonance formed by two photonic band gap reflectors and the standing wave mode formed by periodic structures are discussed. We conclude that the highly-dispersive characteristics originate from the resonator-like aspect of the photonic crystal waveguide.

• Structural Engineering and Mechanics
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• v.86 no.2
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• pp.157-165
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• 2023

In the present work, the vibration characteristics of sandwich nanocomposite shells, fortified with graphene platelets (GPLs) have been researched. The shell has been considered as the stadium roof shape with double curvatures under vibration due to earthquake. The nanocomposite has the matrix of concrete which is fortified with uniform or linear dispersions of GPLs. Also, the core possesses cellular type square architecture for which the effective elastic modulus has been defined in the context of relative density based relations. Based upon the classic shell strains containing two identical curvatures, the governing equations have been established and solved through differential quadrature approach. It will be seen that the vibrational frequencies rely on the core relative density, height of layers, the amount and dispersions of GPLs and even shell geometric parameters.

• The Bulletin of The Korean Astronomical Society
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• v.12
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• pp.7.2-7.2
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• 1987

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.05a
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• pp.35-35
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• 2001

• Proceedings of the Korean Society of Rheology Conference
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• 2002.05a
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• pp.117-120
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• 2002

• Journal of Pharmaceutical Investigation
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• v.40 no.1
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• pp.9-14
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• 2010

Lacidipine used for the treatment of hypertension has low water solubility and is classified as BCS Class II category. Gelucire-based solid dispersions (SD) containing lacidipine were prepared by solvent evaporation method to enhance drug dissolution. The powdered forms of SD showed irregularly spherical shape. Thermal behaviors of SD from differential scanning calorimetry indicated that distinct endothermic peak of lacidipine ($184^{\circ}C$) was shifted to lower region ($150.1^{\circ}C$). Drug was present in a crystalline form. NMR spectra also showed some molecular interaction between drug and Gelucire. There was no significant difference in DSC and NMR behaviors between Gelucire 44/14 and Gelucire 50/13. The initial dissolution rate of SD-loaded tablet linearly increased both in water and in water containing 1% tween 20, and much higher than the commercial tablet, $Vaxar^{(R)}$. When the amount of SD was increased, the release rate was greater. The Gelucire 50/13 showed higher dissolution than the Gelucire 44/14. The produced solid dispersion with various kinds of excipients and making tablets, it was found that solid dispersions can increase the solubility in artificial gastric juice and finally increases dissolution rate.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.207-213
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• 2006

The effects of gellan gum (from S. paucimobilis), EPS-CB (exopolysaccharide from S. chungbukensis), and a series of commercial gums (arabic gum, xanthan gum, guar gum, deacyl gellan gum), on the swelling, rheological, and pasting properties of non-waxy rice flour dispersions were investigated. The swelling properties of rice flours in gellan or guar gum dispersion after heating were found to have increased with increasing gum concentrations, but the swelling properties of rice flour/other gum systems decreased with increasing concentrations. The rice flour/gum mixtures showed high shear-thinning flow behavior (n=0.14-0.32), and consistency index (K) was higher in guar gum than other gum dispersions. The initial pasting temperatures and peak times increased along with increasing gum concentration. The peak viscosity of rice flour increased in guar gum and deacyl gellan dispersions, and the breakdown and setback viscosity of the rice flour paste was lowest in the xanthan gum system, but remained higher than those of the control. The apparent viscosities of the rice flour/gellan gum mixture pastes were the highest among the tested combinations.

• YAKHAK HOEJI
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• v.37 no.3
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• pp.216-227
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• 1993

Complex formations of practically insoluble antelmintic drugs such as mebendazole (MBZ), albendazole (ABZ) and flubendazole (FBZ) with dimethyl-$\beta$-cyclodextrin (DM-$\beta$-CyD) and 2-hydroxypropyl-$\beta$-cyclodextrin (HP-$\beta$-CyD) together with $\alpha$-, $\beta$- and $\gamma$-cyclodextrins(CyDs) in duffered solutions were investigated by solubility method. $A_{L}$ type phase solubility diagrams were obtained in all cases except for the complexation (B$_{s}$, type) of FBZ with $\gamma$-CyD. The highest stability constants were obtained with DM-$\beta$-CyD, followed by $\alpha$-CyD > $\beta$-CyD > HP-$\beta$-CyD > $\gamma$-CyD for ABZ, and HP-$\beta$-CyD > $\gamma$-CyD > $\beta$-CyD > $\alpha$-CyD for FBZ at pH 1.2. On the other hand, solid dispersion systems of ABZ and FBZ with $\beta$- and DM-$\beta$-CyDs were prepared by solvent evaporation method and evaluated by dissolution, differential thermal analysis and powder x-ray diffractometry. The dissolution rates of ABZ- and FBZ-DM-$\beta$-CyD solid dispersions were much faster than those of drugs alone, corresponding physical mixtures and tablets on market both at pH 1.2 and 6.8. Although dissolution rates of all samples at pH 6.8 were by far lower than those obtained at pH 1.2, as explained by pH-solubility profiles for ABZ and FBZ, the dissolution rates at pH 6.8 of ABZ from $\beta$- and DM-$\beta$-CyD solid dispersions exceeded the respective equilibrium solubility (23.9 $\mu\textrm{g}$/ml). Fast dissolution of ABZ from solid dispersions with CyDs was attributed to the reduction of drug crystallinity and particle size which was supported by DTA and powder x-ray diffractometry. Consequently these results suggest that solid dispersion systems with CyDs may provide useful means to markedly enhance the solubility and dissolution of benzimidazole antelmintic drugs.