• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.6
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• pp.279-283
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• 2003

In this study, ZnTe : S single crystal thin films substituted by sulfur were grown on GaAs (100) substrates by hot-wall epitaxy. The photoluminescence (PL) characteristics of ZnTe : S single crystal thin films was measured to investigate the effects due to sulfur atoms in the ZnTe layer. The Peak of 2.339 eV identified as the isoelectronic center was observed in low temperature PL spectrum, but PL spectra which the origin had not been well-explained were not observed. Temperature dependence of PL intensities of the light hole free exciton was explained by extrinsic self-trapping. Besides it is reported that the emission lines near absorption edge at room temperature were observed.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.494-498
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• 2003

The transition from aromatics to heteroaromatics is very attractive since it provides an extremely large structural variety, the chemical functionality as well as the possibilities for electronic tuning of the fullerene properties. A synthesis of heterofullerenes in macroscopic quantities is unknown however the spectrometric detection of $C_{59}B$ has been reported. The electronic structures of $C_{(60-2x)}(BN)_x$ systems, isoelectronic with $C_{60}$ have been explored by Extended Hukel, AM1 and ab initio methods. The polyhedral assembly energy are 7.7 kcal greater than $C_{60}$ when one B-N unit is substituted with C-C unit. The assembly energies are getting bigger if more B-N unit is introduced. We focus on HOMO-LUMO energy gap and the stability effects in $C_{(60-2x)}(BN)_x$ with different compositions of $(BN)_x$ moiety. The bonding properties of the substituent atoms were investigated in detail.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.1
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• pp.214-224
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• 2002

High concentrated $TiO_2$ nano colloids were synthesized by sol-gel method. Reactions were performed in $TiCl_4$/HCl/$H_2O$ aqueous solution and the conditions of particles such as shape, size and aggregation, etc. were controlled by polymerization and adsorption of acrylamide in surface of $TiO_2$ nano particles. And also, aminopropyltriethoxysilane was added instead of acrylamide and compared each other. The prepared colloids were well dispersed and showed the strong absorption peaks at 350nm-370nm which is blue shifted to 20-30nm, compared to macro particles. The obtained techniques from $TiO_2$ nato colloids synthesis were utilized in coating on boron nitride powders which are nonpolar and isoelectronic materials of carbon. Their surface morphology, structure, thermal stability and U. V absorption chracteristics were examined by SEM(Scanning Electron Microscopy), XRD(X-ray diffraction), TG/DTA(Thermogravimetric and Differential Thermal Analysis), UV-VIS(Ultraviolet-Visible Spectroscopy).

• Journal of Microbiology and Biotechnology
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• v.24 no.6
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• pp.748-755
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• 2014

In the genome annotation of Escherichia coli MG1655, the orf382 (1,149 bp) is designated as a gene encoding an alcohol dehydrogenase that may be Fe-dependent. In this study, the gene was amplified from the genome by PCR and overexpressed in Escherichia coli BL21(DE3). The recombinant $6{\times}$His-tag protein was then purified and characterized. In an enzymatic assay using different hydroxyl-containing substrates (n-butanol, $\small{L}$-threonine, ethanol, isopropanol, glucose, glycerol, $\small{L}$-serine, lactic acid, citric acid, methanol, or $\small{D}$-threonine), the enzyme showed the highest activity on $\small{L}$-threonine. Characterization of the mutant constructed using gene knockout of the orf382 also implied the function of the enzyme in the metabolism of $\small{L}$-threonine into glycine. Considering the presence of tested substrates in living E. coli cel ls and previous literature, we believed that the suitable nomenclature for the enzyme should be an $\small{L}$-threonine dehydrogenase (LTDH). When using $\small{L}$-threonine as the substrate, the enzyme exhibited the best catalytic performance at $39^{\circ}C$ and pH 9.8 with $NAD^+$ as the cofactor. The determination of the Km values towards $\small{L}$-threonine (Km = $11.29{\mu}M$), ethanol ($222.5{\mu}M$), and n-butanol ($8.02{\mu}M$) also confirmed the enzyme as an LTDH. Furthermore, the LTDH was shown to be an ion-containing protein based on inductively coupled plasma-atomic emission spectrometry with an isoelectronic point of pH 5.4. Moreover, a circular dichroism analysis revealed that the metal ion was structurally and enzymatically essential, as its deprivation remarkably changed the ${\alpha}$-helix percentage (from 12.6% to 6.3%).