• Laser Solutions
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• v.8 no.3
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• pp.5-10
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• 2005

[ $InxGa_{1-x}P/GaAs$ ] structures were grown by chemical beam epitaxy(CBE), Pure phosphine($PH_3$) gases were used as group V sources. for the group III sources, TEGa, TmIn were used. $InxGa_{1-x}P$ epilayer was grown on SI-GaAs substrate and has a 1-${\mu}m$ thick. We have investigated the characteristics of $InxGa_{1-x}P$ by the photoreflectance(PR) spectroscopy, The PR spectrum of $InxGa_{1-x}P$ shows third-derivative feature whose Peaks Provide energy gap. The energy gap of $InxGa_{1-x}P$ has deduced composition x. From temperature dependance of PR spectra, temperature coefficient is $dEg/dT=-3.773{\times}10^{-4}$ eV/K, and Varshni coefficients $\alpha$ and $\beta$ values obtained $4{\times}10^4$ eV/K and 267 K respectively. Also, interaction $\alpha$B was 19.4 meV using the Bose-Einstein temperature relation, and $\Theta$ value related the average phonon frequency were 101.4 K. In particular, shoulder peak related to defects observed in PR signal that measured in temperature 82 K.

• BMB Reports
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• v.42 no.12
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• pp.817-822
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• 2009

Type-1 phosphatase (PP-1) was assessed in foot muscle (FM) and hepatopancreas (HP) of estivating (EST) Otala lactea. Snail PP-1 displayed several conserved traits, including sensitivity to inhibitors, substrate affinity, and reduction in size to a 39 kDa catalytic subunit (PP-1c). During EST, PP-1 activity in FM and HP crude extracts was reduced, though kinetics and protein levels of purified PP-1c isoforms were not altered. PP-1c protein levels increased and decreased in nuclear and glycogen-associated fractions, respectively, during EST. Gel filtration determined that a 257 kDa low $K_m$ PP-1$\alpha$ complex decreased during estivation whereas a 76 kDa high $K_m$ complex increased in EST. Western blotting confirmed that the 76 kDa protein consisted of PP-1$\alpha$ and nuclear inhibitor of PP-1 (NIPP-1). A suppression of PP-1 activity factors in the overall metabolic rate depression in estivating snails and the mechanism is mediated through altered cellular localization and interaction with binding partners.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.237-242
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• 1998

A transparent and colorless $80SiO_2-20TiO_2$(mol%) thin films on soda-lime-silica slide glass and sapphire substrate were obtained by spin-coating technique using tetraethyl orthosilicate and titanium trichloride as starting materials. The prepared film annealed at $750^{\circ}C$ showed a high transmittance and a low reflectance. For the $SiO_2-TiO_2$ films on slide glasses, a strong interaction between the sodium ion and oxygens is properbly the origin of the good stability to the high temperature and the high humidity.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.215-220
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• 2004

Molecular Dynamics(MD) method was used to investigate the change of friction force due to interaction between dislocations and a grain boundary when a Ni tip was scratched on a Cu bicrystal. The substrate comprised a Cu bicrystal containing a vertical$\Sigma=5(210)$ grain boundary. The moving tip for scratching simulation was consisted of fixed Ni atoms emulating a rigid tip. The indentation depth was $3.6\AA$ and the scratching was performed along <110>direction in the first grain. As the scratching was continued, nucleation and propagation of dislocations were observed. In the early stage, the grain boundary played as a barrier to moving dislocations and interrupting further dislocation movement with no dislocation resulting in no propagation across the grain boundary. As the Ni tip approached the grain boundary, dislocations were nucleated at the grain boundary and propagated to the second grain. However, stick-slip phenomena that were observed on a single crystal scratching were not observed in the bicrystal. And, instead, irregular oscillation of friction force was observed during the scratching due to the presence of a grain boundary.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1047-1052
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• 2006

A bile salt hydrolase (BSH) was purified from Lactobacillus plantarum CK 102 and its enzymatic properties were characterized. This enzyme was successfully purified using ion-exchange chromatography with Q-Excellose and hydrophobic interaction chromatography with Butyl-Excellose. The purified enzyme showed a single protein band of 37 kDa by SDS-polyacrylamide gel electrophoresis, which was similar to the molecular weight of known BSHs. The amino acid sequence of GLGLPGDLSSMSR, determined by MALDI-TOF, was identical to that of BSH of L. plantarum WCFS1. Although this BSH hydrolyzed all of the six major human bile salts, glycine-conjugated bile acid was the best substrate, based on its specificity and $K_{m}$ value. Among the various substrates, the purified enzyme maximally hydrolyzed glycocholate with apparent $K_{m}$ and $V_{max}$ values of 0.5 mM and 94 nmol/min/mg, respectively. The optimal pH of the enzyme ranged from 5.8 to 6.3. This enzyme was strongly inhibited by thiol enzyme inhibitors such as iodoacetate and periodic acid.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.4
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• pp.347-351
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• 2008

In this paper, a new co-planar waveguide ultra-wideband aperture is designed as wireless application in ships. The designed antenna consists of a rectangular aperture on a determined ground plane and a mushroom shaped stub. The mushroom-shaped stub, which is simple, convenient to analyze and optimise, has less parameters. This antenna has compact aperture size $21.1{\times}8.1mm^2$, designed on FR-4 substrate with dielectric constant of 4.3, thickness of 1.5mm. CPW fed planar antenna has the advantages of wide-bandwidth, low-cost and easy interaction with the radio frequency front end circuitry.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1113-1119
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• 2007

Human bone marrow-derived mesenchymal stem cells (hBMMSCs) must differentiate into osteogenic cells to allow for successful bone regeneration. In this study, we investigated the effects of different combinations of three soluble osteogenic differentiation-inducing factors [L-ascorbic acid (AC), ${\beta}$-glycerophosphate (${\beta}G$), and bone morphogenic protein-2 (BMP-2)] and the presence of a hydroxyapatite (HA) substrate on hBMMSC osteogenic differentiation in vitro. hBMMSCs were cultured in medium containing various combinations of the soluble factors on culture plates with or without HA coating. After 7 days of culture, alkaline phosphatase (ALP) activity, calcium deposition, and osteoprotegerin (OPG) and osteopontin (OPN) expression were measured. The effects of individual and combined factors were evaluated using a factorial analysis method. BMP-2 predominantly affected expression of early markers of osteogenic differentiation (ALP and OPG). HA had the highest positive effect on OPN expression and calcium deposition. The interaction between AC, ${\beta}G$, and HA had the second highest positive effect on ALP activity.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.1
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• pp.91-99
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• 2018

Protein phosphatase 1 (PP1) is involved in various signal transduction mechanisms as an extensive regulator. The PP1 catalytic subunit (PP1c) recognizes and binds to PP1-binding consensus residues (FxxR/KxR/K) in NBCe1-B. Consequently, we focused on identifying the function of the PP1-binding consensus residue, $^{922}FMDRLK^{927}$, in NBCe1-B. Using site-directed mutagenesis and co-immunoprecipitation assays, we revealed that in cases where the residues were substituted (F922A, R925A, and K927A) or deleted (deletion of amino acids 922-927), NBCe1-B mutants inhibited PP1 binding to NBCe1-B. Additionally, by recording the intracellular pH, we found that PP1-binding consensus residues in NBCe1-B were not only critical for NBCe1-B activity, but also relevant to its surface expression level. Therefore, we reported that NBCe1-B, as a substrate of PP1, contains these residues in the C-terminal region and that the direct interaction between NBCe1-B and PP1 is functionally critical in controlling the regulation of the ${HCO_3}^-$ transport. These results suggested that like IRBIT, PP1 was another novel regulator of ${HCO_3}^-$ secretion in several types of epithelia.

• Macromolecular Research
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• v.15 no.4
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• pp.343-347
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• 2007

Novel composite membranes, which delivered high separation performance for propylene/propane mixtures, were developed by coating inert poly(ethylene-co-propylene) rubber (EPR) onto a porous polyester substrate, followed by the physical distribution of $AgBF_4$. Scanning electron microscopy-wavelength dispersive spectrometer (SEM-WDS) revealed that silver salts were uniformly distributed in the EPR layer. The physical dispersion of the silver salts in the inert polymer matrix, without specific interaction, was characterized by FT-IR and FT-Raman spectroscopy. The high separation performance was presumed to stem from the in-situ dissolution of crystalline silver ionic aggregates into free silver ions, which acted as an active propylene carrier within a propylene environment, leading to facilitated propylene transport through the membranes. The membranes were functional at all silver loading levels, exhibiting an unusually low threshold carrier concentration (less than 0.06 of silver weight fraction). The separation properties of these membranes, i.e. the mixed gas selectivity of propylene/propane ${\sim}55$ and mixed gas permeance ${\sim}7$ GPU, were stable for several days.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.191-196
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• 2008

Kinetic studies of the reactions of a-bromoacetanilides [YC6H4NHC(=O)CH2Br] with substituted benzylamines (XC6H4CH2NH2) have been carried out in dimethyl sulfoxide at 35.0 oC. The Hammett plots for substituent (Y) variations in the substrate (log kN vs. sY) are biphasic concave upwards/downwards with breaks at Y = 4-Cl (sY = 0.23). The Hammett coefficients rY and the cross-interaction constant rXY (= +0.16) are positive for sY 0.23, while the rY values are positive/negative [rY > 0 for X = (4-MeO and 4-Me) and rY < 0 for X = (H, 4-Cl and 3-Cl)] and the rXY (= -1.51) value is negative for sY ³ 0.23. Based on these and other results, the benzylaminolyses of a-bromoacetanilides are proposed to proceed through rate-limiting expulsion of the bromide leaving group from a zwitterionic tetrahedral intermediate, T, with a bridged transition state for s Y 0.23, while the reaction proceeds through concerted mechanism with an enolate-like TS in which the nucleophile attacks the a-carbon for s Y ³ 0.23.