• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.470-473
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• 2000

Since the biosynthetic production of indigo and indirubin normally reflects a difficult process including the toxicity of indole to microorganisms, only several bacterial strains have been exploited to produce indigo and indirubin from indole or its derivatives. P. savastanoi BCNU 106, which was a gram negative bacterium, was isolated and tolerant to 10% (v/v) toluene. The indole tolerance level of P. savastanoi BCNU 106 was as high as 160 mg/ml when toluene or p-xylene was added to the medium to 20% by volume. P. savastanoi BCNU 106 grown in a two-phase culture system containing indole(100 mg/ml) and P-xylene (0.2 ml/ml) produced P-xylene-soluble pigments, blue indigo and purple indirubin. Of the conditious tried, the production of indigo and indirubin was found only when P. savastanoi BCNU 106 was grown in the two-phase system overlaid with the organic solvents with appropriate polarity. This study may illustrate that the isolated extremophile P. savastanoi could be used in the microbial conversion process of the industrial potentials.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.290-296
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• 1999

We have studied the phase separation and ordering phenomeon of InAlAs epilayers grown on InP substrate by LP-MOCVD with DCXRD, PL, and TEM. From the intensity and FWHM of DCXRD and PL, we observed that the structural and optical quality of InAlAs epilayers were improved as growth temperature increased. The band-gap reduction due to phase separation and ordering is 291, 246, and 28 meV in the InAlAs epilayers grown at $565^{\circ}C$, $615^{\circ}C$, and $700^{\circ}C$, respectively, and shows the same from the InAlAs epilayer town at 5$65^{\circ}C$ in which the HRTEM micrograph showed the lattice fringe between InAs-rich and AlAs-rich regions was tilted by $2^{\circ}$ due to composition difference. However the maximum degree of ordering by intensity of extra spots was obtained at medium growth temperature. The annealing experiment by RTA of sample grown at $565^{\circ}$ shows a maximum band-gap shift of 78eV at $880^{\circ}$ for 3 min, and TEM shows that the origin of the blue shift of band-gap is the complete disappearance of ordering. Through annealing we can conclude that short time annealing affects only ordering and that most of the total band-gap reduction (~3/4) occurs by phase separation.

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.343-352
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• 2010

A zirconia gel/polymer hybrid nanofiber was produced in a nonwoven fabric mode by electrospinning a sol derived from hydrolysis of zirconium butoxide with a polyvinyl butyral. Results indicated that the hydroxyl groups on the vinyl alcohol units in the backbone of the polymer were involved in the hydrolysis as well as grafting the hydrolyzed zirconium butoxide. In addition, use of acetic acid as a catalyst resulted in further hydrolysis and condensation in the sol, which led to the growth of -Zr-O-Zr- networks among the polymer chains. These networks gradually transformed into a crystalline zirconia structure upon heating. The as-spun fiber was smooth but partially wrinkled on the surface. The average fiber diameter was $690{\pm}110\;nm$. The fiber exhibited a strong but broad blue photoluminescence with its maximum intensity at a wavelength of ~410 nm at room temperature. When the fiber was heat-treated at $400^{\circ}C$, the fiber diameter shrunk to $250{\pm}60\;nm$. Nanocrystals which belonged to a tetragonal zirconia phase and were ~5 nm in size appeared. A strong white photoluminescence was observed in this fiber. This suggests that oxygen or carbon defects associated with the formation of the nanocrystals play a role in generating the photoluminescence. Further heating to $800^{\circ}C$ resulted in a monoclinic phase beginning to form In the heat-treated fibers, coloring occurred but varied depending on the heating temperature. Crystallization, coloring, and phase transition to the monoclinic structure influenced the photoluminescence. At $600^{\circ}C$, the fiber appeared to be fully crystallized to a tetragonal zirconia phase.

• Journal of Life Science
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• v.29 no.6
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• pp.679-687
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• 2019

Litsea populifolia, a plant species of the Lauraceae family, is widely distributed in the tropical and subtropical areas of Asia. The phylogenetic relationships and botanical characteristics of L. populifolia have been reported; however, its anti-oxidative and anti-cancer activities remain unclear. In this study, we evaluated the anti-oxidative and anti-cancer effects of ethanol extracts of L. populifolia (EELP) together with the molecular mechanism of its anti-cancer activity in human lung adenocarcinoma A549 cells. EELP showed significant anti-oxidative effects with a 50% inhibitory concentration at $11.71{\mu}g/ml$, which was measured by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. EELP exhibited cytotoxic activity and induced cell cycle arrest at the G1 phase in A549 cells in a dose-dependent manner, whereas EELP did not have the cytotoxic effect on the normal human lung cell line IMR90. Treatment with EELP also resulted in a decreased expression of G1/S transition-related molecules-including cyclin-dependent kinase (CDK) 2, CDK6, cyclin D1, and cyclin E-both for the transcription and translation levels. EELP-induced G1 arrest was associated with the phosphorylation of checkpoint kinase 2 (CHK2), p53, cell division cycle 25 homolog A (CDC25A), and the reduction of CDC25A expression in A549 cells. Collectively, these results suggest that EELP may exert an anti-cancer effect by cell cycle arrest at the G1 phase through both p53-dependent and p53-independent (ATM/CHK2/CDC25A/CDK2) pathways in A549 cells.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.73-83
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• 2014

CFD(computational fluid dynamics) model is developed to simulate direct injection of ammonia gas phase from ammonia transporting materials into the SCR catalyst in the exhaust pipe of the engine with solid SCR. Configurations of one-hole and four-hole nozzle, circumferential type, porous tube type, and the effect of mixer configurations which commonly used in liquid injection of AdBlue are considered for complex geometries. Mal-distribution index related to concentration of ammonia gas, flow uniformity index related to velocity distribution, and pressure drop related to flow resistance are compared for different configurations of complex geometries at the front section of SCR catalyst. These results are used to design the injection system of ammonia gas phase for solid SCR of target vehicle.

• BMB Reports
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• v.32 no.6
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• pp.521-528
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• 1999

The folding of recombinant hepatitis B virus X-protein (rHBx) solubilized from Escherichia coli inclusion bodies was investigated. By sequential dialysis of urea, rHBx was folded into its native structure, which was demonstrated by the efficacy of its transcriptional activation of the adenovirus major late promoter (MLP), fluorescence spectroscopy, and circular dichroism (CD) analysis. The decrease in CD values at 220 nm and a corresponding blue shift of the intrinsic fluorescence emission confirmed the ability of rHBx to refold in lower concentrations of urea, yielding the active protein. Equilibrium and kinetic studies of the refolding of rHBx were carried out by tryptophan fluorescence measurements. From the biphasic nature of the fluorescence curves, the existence of stable intermediate states in the renaturation process was inferred. Reverse phase-high performance liquid chromatography (RP-HPLC) analysis further demonstrated the existence of these intermediates and their apparent compactness.

• Journal of the Korean Ceramic Society
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• v.54 no.1
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• pp.70-74
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• 2017

Up-conversion (UC) and down-conversion (DC) luminescence of $LuNbO_4:0.18Yb^{3+}$, $xEr^{3+}$ (x = 0.01-0.07) powders were investigated. Post-annealed powders were composed of a single $LuNbO_4$ phase with a monoclinic fergusonite structure, whereas as-calcined powders contained a small amount of the $Li_3NbO_4$ impurity phase. Under near infrared radiation, the UC spectra of the post-annealed powders exhibited the strong green and weak red emission peaks assigned to the transition of $^2H_{11/2}/^4S_{3/2}$ and $^4F_{9/2}$ to the ground state ($^4I_{15/2}$) of $Er^{3+}$ ions, respectively; the green and red emission intensities were approximately 330 and 270% stronger, respectively, than those of the as-calcined powders. A two-photon UC process was involved in the emission as a result of an energy transfer from $Yb^{3+}$ to $Er^{3+}$. Under ultraviolet radiation, the DC spectra exhibited broad blue and sharp green emission bands. The DC mechanism was explained using self-activated $[NbO_4]^{3-}$ niobates and an energy transfer from $[NbO_4]^{3-}$ to $Er^{3+}$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.2
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• pp.94-99
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• 1995

Potassium lithium niobate (KLN) crystals, grown by the micro pulling down $({\mu}-PD)$ method, have been considered on the interchange between incongruent melt composition and second harmonic generation (SHG) properties because of the sensitive interaction. Correlation between the composition of crystals and the wavelength of SHG applications from ultra - violet to green region was found. Also, the ${\mu}-PD KLN$ KLN crystals showed a homogeneity of noncritical phase matching and an excellent SHG property which is converted to blue laser light with half wavelength by the red irradiation.

• Current Optics and Photonics
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• v.4 no.5
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• pp.428-433
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• 2020

Recently, the on-chip autofocus (AF) function has become essential to the CMOS image sensor. An auto-focus usually operates using phase detection of the photocurrent difference from a pair of AF pixels that have focused or defocused. However, the phase-detection method requires a pair of AF pixels for comparison of readout. Therefore, the pixel variation may reduce AF performance. In this paper, we propose a color-selective AF pixel with a plasmonic nanostructure in a 0.9 μ㎡ pixel. The suggested AF pixel requires one pixel for AF function. The plasmonic nanostructure uses metal-insulator-metal (MIM) stack arrays instead of a color filter (CF). The color filters are formed at the subwavelength, and they transmit the specific wavelength of light according to the stack period and incident angles. For the optical analysis of the pixel, a finite-difference time-domain (FDTD) simulation was conducted. The analysis showed that the MIM stack arrays in the pixels perform as an AF pixel. As the primary metric of AF performance, the resulting AF contrasts are 1.8 for the red pixels, 1.6 for green, and 1.5 blue. Based on the simulation results, we confirmed the autofocusing performance of the MIM stack arrays.

• Journal of the Korean Ceramic Society
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• v.54 no.5
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• pp.422-428
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• 2017

Single-phase yellow phosphor, $CaGd_{2-x}ZrSc(AlO_4)_3:xCe^{3+}$ ($CGZSA:Ce^{3+}$), possessing cubic symmetry with varied $Ce^{3+}$ concentrations, was synthesized using the solid-state reaction method. The samples were characterized using X-ray diffraction (XRD), excitation spectra, emission spectra, thermal quenching, and decay curves. The cubic phase of $CGZSA:Ce^{3+}$ phosphor was confirmed via XRD analysis. The photoluminescence spectra of $CGZSA:Ce^{3+}$ phosphor demonstrated that the phosphor could be excited at the wavelength of 440 nm; a broad yellow emission band was centered at 541 nm. These results indicate that the phosphors are adequately excited by blue light and have the potential to function as yellow-emitting phosphors for applications in white light-emitting diodes.