• Current Photovoltaic Research
• /
• v.1 no.2
• /
• pp.73-81
• /
• 2013

Heterojunction with Intrinsic Thin-layer (HIT) solar cells are currently an important subject in industrial trends for thinner solar cell wafers due to the low-temperature of production processes, which is around $200^{\circ}C$, and due to their high-efficiency of 24.7%, as reported by the Panasonic (Sanyo) group. The use of thinner wafers and the enhancement of cell performance with fabrication at low temperature have been special interests of the researchers. The fundamental understanding of the band bending structures, choice of materials, fabrication process, and nano-scale characterization methods to provide necessary understanding of the interface passivation mechanisms, emitter properties, and requirements for transparent oxide conductive layers is presented in this review. This information should be used for the performance characterization of the developing technologies for HIT solar cells.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.11
• /
• pp.3272-3278
• /
• 2010

Synthesis and structural characterization of peripherally ferrocene-substituted zinc phthalocyanine (ZnPc-Fc) were carried out for efficient far-red/near-IR performance in dye-sensitized nanostructured $TiO_2$ solar cells. Incorporating ferrocene into phthalocyanine strongly improved the dye solubility in polar organic solvents, and reduced surface aggregation due to the steric effect of bulky ferrocene substituents. The involvement of electron transfer reaction pathways between ferrocene and phthalocyanine in ZnPc-Fc was evidenced by completely quenched fluorescence from S1 state (< 0.08% vs ZnPc). Strong absorption bands at 542 and 682 nm were observed in the transient absorption spectroscopy of ZnPc-Fc in DMSO, which was excited at a 670 nm laser pulse with a 15 ps full width at half maximum. Also, the excited state absorption signals at 450 - 600 and 750 - 850 nm appeared from the formation of charge separated state of phthalocyanine's anion. The lifetime of the charge separate state in ZnPc-Fc was determined to be $170{\pm}8$ ps, which was almost 17 times shorter than that of the ZnPc.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1985.08b
• /
• pp.35-48
• /
• 1985

Plastids, which are organelles unique to plant cells, bear their own genome that is organized into DNA-protein complexes (nucleoids). Regulation of gene expression in the plastid has been extensively investigated because this organelle plays an important role in photosynthesis. Few attempts, however, have been made to characterize the regulation of plastid gene expression at the chromosomal structure, using plastid nucleoids. In this report, we summarize the recent progress in the characterization of DNA-binding proteins in plastids, with special emphasis on CND41, a DNA binding protein, which we recently identified in the choloroplast nucleoids from photomixotrophically cultured tobacco cells. CND41 is a protein of 502 amino acids which consisted of a transit peptide of 120 amino acids and a mature protein of 382 amino acids. The N-terminal of the 'mature' protein has lysine-rich region which is essential for DNA-binding. CNA41 also showed significant identities to some aspartyl proteases. Protease activity of purified CND41 has been recently confirmed and characterized. On the other hand, characterization of accumulation of CND41 both in wild type and transgenic tobacco with reduced amount of CND41 suggests that CND41 is a negative regulator in chloroplast gene expression. Further investigation indicated that gene expression of CND41 is cell-specifically and developmentally regulated as well as sugar-induced expression. The reduction of CND41 expression in transgenic tobacco also brought the stunted plant growth due to the reduced cell length in stem. GA3 treatment on apical meristem reversed the dwarf phenotype in the transformants. Effects of CND41 expression on GA biosynthesis will be discussed

• Bulletin of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.1120-1126
• /
• 2013

The syndecan family consists of four transmembrane heparan sulfate proteoglycans present in most cell types and each syndecan shares a common structure containing a heparan sulfate modified extracellular domain, a single transmembrane domain and a C-terminal cytoplasmic domain. To get a better understanding of the mechanism and function of syndecan-4 which is one of the syndecan family, it is crucial to investigate its three-dimensional structure. Unfortunately, it is difficult to prepare the peptide because it is membrane-bound protein that transverses the lipid bilayer of the cell membrane. Here, we optimize the expression, purification, and characterization of transmembrane, cytoplasmic and short extracellular domains of syndecan4 (syndecan-4 eTC). Syndecan-4 eTC was successfully obtained with high purity and yield from the M9 medium. The structural information of syndecan-4 eTC was investigated by MALDI-TOF mass (MS) spectrometry, circular dichroism (CD) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. It was confirmed that syndecan-4 eTC had an ${\alpha}$-helical multimeric structure like transmembrane domain of syndecan-4 (syndecan-4 TM) in membrane environments.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.1
• /
• pp.172-176
• /
• 2009

The nature and morphology of titanium dioxide films play a significant role in determining the overall efficiency of dye-sensitized solar cell (DSSCs). In this work, the preparation of nanostructured titania particles by sol-gel method (SG-$TiO_2$) and its characterization were investigated for the application of DSSCs. The samples were characterized by XRD, XPS, FE-SEM, BET and FT-IR analysis. The energy conversion efficiency of SG-$TiO_2$ was approximately 8.3 % under illumination with AM 1.5 (100 mW/$cm^2$) simulated sunlight. DSSCs made of SG-$TiO_2$ nanocrystalline films as photoanodes achieved better energy conversion efficiency compared to those prepared using commercially available Degussa P25.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.1
• /
• pp.63-67
• /
• 1998

The synthesis and characterization of the monomeric group 13 heterocyclic thiosemicarbazone complexes $Me_2M[SC_4H_3CHNNC(S)SCH_3]$ (M=Al (2), Ga (3)) are described. Compounds 2-3 were prepared using $MMe_3$ (M=Al, Ga) in toluene with 2-thiophenecarboxaldehyde-S-methyldithiocarbazat e under anaerobic conditions. These complexes have been characterized by $^1H\;NMR,\; ^{13}C\; NMR$, elemental analyses, and single-crystal X-ray diffraction. 2 crystallizes in the monoclinic space group $P2_1/c$ with unit cell parameters a=10.2930(5) Å, b=18.564 (1) Å, c=7.3812(6) Å, V=1347.9(2) Å3, $D_{calc}=1.342\; gcm^{-3}$ for Z=4, 9281 reflections with $I_o<3{\sigma}\;(I_o),$ R1=0.0500 and wR2=0.0526. 3 crystalizes in the orthorhombic space group $P_{bca}$ with unit cell parameters a=13.340(3) Å, b=19.9070(5) Å, c=11.3690(2) Å, $V=2673.88(9)\;{\AA}^3$, $D_{calc}=1.511\; gcm^{-3}$ for Z=8, 17004 reflections with $I_o>3{\sigma}\;(I_o),$, R1=0.0480 and wR2=0.0524. Compound 3 is a monomeric gallium compound with a weak interaction between the pendant thiophene and the gallium center.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.235-238
• /
• 2005

Sulfonated poly(ether sulfone) copolymers (PESs) were synthesized using hydroquinone 2-potassium sulfonate (HPS) with other monomers (bisphenol A and 4-fluorophenyl sulfone). PESs with different $mole\%$ of hydrophilic group were prepared by changing the mole ratio of HPS in the polymerization reaction. The chemical structure and the thermal stability of these polymers were characterized by using $^1H-NMR$, FT-IR and TGA techniques. The PES 60 membrane, which has $60 mole\%$ of HPS unit in the polymer backbone, has a proton conductivity of 0.091 S/cm and good insolubility in boiling water. The TGA showed that PES 60 was stable up to $272^{\circ}C$ with a char yield of about $29\%\;at\;900^{\circ}C\;under\;N_2$ atmosphere. To investigate the single cell performance, the catalyst coated PES 60 membrane was used and a single cell test was carried out using $H_2/O_2$ gases as fuel and oxidant at various temperatures. We observed that the cell performance was enhanced by increasing the cell temperature. A current density of $1400 mA/cm^2$ at 0.60 V was obtained at $70^{\circ}C$.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.4
• /
• pp.732-736
• /
• 2010

Five strains of tannic acid degrading bacteria were isolated and identified by phenotypic characterization. All the five isolates showed cell-associated activity, whereas only three showed extracellular activity. Serratia ficaria DTC, showing the highest cell-associated activity (0.29 U/l), was selected for further shake-flask studies. Tannase synthesis was growth associated and reached the peak in the late stationary phase of growth. Organic nitrogen sources enhanced the tannase production. Peak tannase production of 0.56 U/l was recorded in the medium having the initial pH of 6. The pH and temperature optima of the enzyme were found to be 8.9 and $35^{\circ}C$, respectively. This is the first report of cell-associated activity in the case of bacterial tannase. Cell-associated tannase of Serratia ficaria DTC could be industrially important from the perspective of its activity at broad temperature and pH ranges, and its unusually high activity at pH 8.9.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.6
• /
• pp.631-638
• /
• 1998

Studies were made to elucidate the cell growth and the production of camptothecin and its derivatives in cell cultures of Camptotheca acuminata. High resolution HPLC chromatograms to analyze camptothecin and 10-hydroxycamptothecin in lactone and carboxylate forms were obtained with a fluorescence detector. Calli inductions were optimized with the young stem of explant on Schenk and Hildebrandt (SH) medium supplemented with 5 mg/l $\alpha$-naphthaleneacetic acid (NAA), 0.2 mg/l 6-benzylamino purine (BAP), 2.0% sucrose, and 0.5% agar. The hybrid medium, a mixture of SH and Murashige and Skoog (MS) salts, was developed for homogeneous suspension cultures without large cell aggregates. The optimum phytohormone concentrations for successful suspension cultures were 1.0mg/l of 2,4-D and 0.5 mg/l of kinetin. The highest growth in suspension cultures was observed when 49.7% (w/w) of the cells was composed of small aggregates which were below 0.1 mm in diameter. Time course changes of cell growth and camptothecin production showed that camptothecin accumulation was started at the end of the growth phase and the maximum content was obtained 10 days after inoculation. Yeast extract elicitor increased camptothecin accumulation 4 times. Methyl jasmonate and jasmonic acid also increased camptothecin production 6 and 11 times, respectively.

• Journal of fish pathology
• /
• v.16 no.3
• /
• pp.165-173
• /
• 2003

A stable cell line, BSBS (black seabream spleen), was established from the cells in spleen of black seabream, Acanthopagrus schlegeli, and characterized. Subculture maintained more than 60 passages and mophologically, BSBS cell was epithelioid cell. The cells grew optimally at 20℃ in Leibovitz's L-15 medium supplemented with 10% fetal bovine serum with incubation temperature of 20℃. BSBS cells supported the growth of marine birnavirus (MABV Y-6), chum salmon reovirus (CSV), spring viremia of carp virus (SVCV) and hirame rhabdovirus (HIRRV). Thus, the new cell line may be useful for studying wide range of fish viruses.