• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.152-153
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• 2006

The new approach to buffer layer design for CIGS solar cells that permitted to reduce the buffer absorption losses in the short wavelength range and to overcome the disadvantages inherent to Cd-free CIGS solar cells was proposed. A chemical bath deposition method has been used to produce a high duality buffer layer that comprises thin film of CdS and Zn-based film. The double layer was grown on either ITO or CIGS substrates and its morphological, structural and optical properties were characterized. The Zn-based film was described as the ternary compound $ZnS_x(OH)_y$. The composition of the $ZnS_x(OH)_y$ layer was not uniform throughout its thickness. $ZnS_x(OH)_y$/CdS/substrate region was a highly intermixed region with gradually changing composition. The short wavelength cut-off of double layer was shifted to shorter wavelength (400nm) compared to that (520 nm) for the standard CdS by optimization of the double buffer design. The results show the way to improve the light energy collection efficiency of the nearly cadmium-free CIGS-based solar cells.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.874-878
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• 2012

In the submerged fermentation of fungi, it was known pH had significant effect on the citric acid production. Various growth conditions were applied with different buffer on citric acid production by Aspergillus niger NRRL 567 grown on peat moss to find the optimum pH and most effective buffer solution. The initial pHs of different buffer solutions significantly influenced on the citric acid production and A. niger NRRL 567 produced citric acid more efficiently at high pHs. A phosphate buffer and a carbonate buffer with pH 8.6 and pH 10.0 were identified as suitable buffer solutions for citric acid production. The maximal citric acid production of 564.3 g/kg solid substrate was achieved employing carbonate buffer at pH 10.0.

• Bulletin of the Korean Chemical Society
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• v.24 no.7
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• pp.943-947
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• 2003

We have studied the migration behavior of single-stranded DNA using capillary gel electrophoresis under various conditions. It was found that optimum electric fields should be less than 150 V/cm for the good tradeoff between the separation time and the resolution. It seems that the gel matrix with the combination of different polymer average molecular weights is important to extend the maximum readable DNA bases. The total gel concentration less than 3.1% in the mixed gel system showed good separation efficiency up to 600 bases. The best result was obtained with the poy(ethylene)oxide (PEO) gel concentration of 1.2% of Mr 8,000,000 and 1.8% of Mr 600,000. We observed that the capillary length between 50 cm to 100 cm (effective length) should be employed for the optimization between the total DNA migration time and the maximum readable length. A trizma base-boric acid-ethlyenediaminetetraacetic acid (EDTA) (TBE) buffer was commonly used for DNA sequencing, but we found that 3-[tris(hydroxymethyl)methyl amino]-1-propane sulfonic acid (TAPS) buffer worked as well for the single-stranded DNA separation. Especially, TAPS buffer showed a good resolution for very short DNA bases (1 to 30 bases).

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.122-127
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• 2005

A size exclusion chromatography (SEC) process, in the presence of denaturant in the refolding buffer was developed to refold recombinant human $interferon-\gamma$ ($rhIFN-\gamma$) at a high concentration. The $rhlFN-\gamma$ was overexpressed in E. coli resulting in the formation of inactive inclusion bodies (IBs). The IBs were first solubilized in 8 M urea as the denaturant, and then the refolding process performed by decreasing the urea concentration on the SEC column to suppress protein aggregation. The effects of the urea concentration, protein loading mode and column height during the refolding step were investigated. The combination of the buffer-exchange effect of SEC and a moderate urea concentration in the refolding buffer resulted in an efficient route for producing correctly folded $rhIFN-\gamma$, with protein recovery of $67.1\%$ and specific activity up to $1.2\times10^7\;IU/mg$.

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.381-385
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• 1975

Calcinated alunite powder (surface area 5100 $cm^2/g$) was found to react with well stirred ammonium buffer solution (pH 8.0) following Jander's equation. The rate constants increase with the amount of solid and temperature of reaction system. The energy of activation for the reactions (at $30{\sim}60^{\circ}C$) was 15.7 kcal/mole. The rate-determining step appears to involve ionization of alunite.

• Journal of the Korean Ceramic Society
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• v.52 no.4
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• pp.290-293
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• 2015

The properties of the IZTO thin films on the glass were studied with a variation of the $SiO_2$ buffer layer thickness. $SiO_2$ buffer layers were deposited by plasma-enhanced chemical vapor deposition (PECVD) on the glass, and the In-Zn-Tin-Oxide (IZTO) thin films were deposited on the buffer layer by RF magnetron sputtering. All the IZTO thin films with the $SiO_2$ buffer layer are shown to be amorphous. Optimum $SiO_2$ buffer layer thickness was obtained through analyzing the structural, morphological, electrical, and optical properties of the IZTO thin films. As a result, the IZTO surface roughness is 0.273 nm with a sheet resistance of $25.32{\Omega}/sq$ and the average transmittance is 82.51% in the visible region, at a $SiO_2$ buffer layer thickness of 40 nm. The result indicates that the uniformity of surface and the properties of the IZTO thin film on the glass were improved by employing the $SiO_2$ buffer layer and the IZTO thin film can be applied well to the transparent conductive oxide for display devices.

• Korean Journal of Materials Research
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• v.21 no.8
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• pp.432-438
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• 2011

In this study, chemical bath deposited (CBD) indium sulfide buffer layers were investigated as a possible substitution for the cadmium sulfide buffer layer in CIGS thin film solar cells. The performance of the $In_2S_3$/CIGS solar cell dramatically improved when the films were annealed at $300^{\circ}C$ in inert gas after the buffer layer was grown on the CIGS film. The thickness of the indium sulfide buffer layer was 80 nm, but decreased to 60 nm after annealing. From the X-ray photoelectron spectroscopy it was found that the chemical composition of the layer changed to indium oxide and indium sulfide from the as-deposited indium hydroxide and sulfate states. Furthermore, the overall atomic concentration of the oxygen in the buffer layer decreased because deoxidation occurred during annealing. In addition, an In-thin layer was inserted between the indium sulfide buffer and CIGS in order to modify the $In_2S_3$/CIGS interface. The $In_2S_3$/CIGS solar cell with the In interlayer showed improved photovoltaic properties in the $J_{sc}$ and FF values. Furthermore, the $In_2S_3$/CIGS solar cells showed higher quantum efficiency in the short wavelength region. However, the quantum efficiency in the long wavelength region was still poor due to the thick buffer layer.

• 한국초전도학회:학술대회논문집
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• 2008.08a
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• pp.56-56
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• 2008

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.500-504
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• 2005

Fusion ferritin (heavy chain ferritin, $F_H+$ light chain ferritin, $F_L$), an iron-binding protein, was primarily purified from recombinant Escherichia coli by two-step sonications with urea [1]. Unfolded ferritin was refolded by gel filtration chromatography (GFC) with refolding enhancer, where 50 mM Na-phosphate (pH 7.4) buffer containing additives such as Tween 20, PEG, and L-arginine was used. Ferritin is a multimeric protein that contains approximately 20 monomeric units for full activity. Fusion ferritin was expressed in the form of inclusion bodies (IBs). The IBs were initially solubilized in 4 M urea denaturant. The refolding process was then performed by decreasing the urea concentration on the GFC column to form protein multimers. The combination of the buffer-exchange effect of GFC and the refolding enhancers in refolding buffer resulted in an efficient route for producing properly folded fusion ferritin.

• Progress in Superconductivity
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• v.3 no.1
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• pp.125-129
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• 2001

NiO buffer layers were deposited on texture Ni tapes fur YBCO coated conductors by MOCVD(metal organic chemical vapor deposition) method, using a single solution source. Variables were deposition temperature and flow rate of $0_2$carrier gas. At higher temperatures, The NiO(111) texture was well developed, but the NiO(200) texture was developed at low temperatures. The best result was obtained at the deposition temperature of$ 470^{\circ}C$ and the gas flow rate of 200 sccm. FWHM value of $\omega$-scan fur NiO(200) of the film and $\Phi$-scan for NiO(111) of the film was $4.2^{\circ}$ and $7^{\circ}$, respectively.