• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1462-1466
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• 2013

We demonstrate that ruthenium oxide ($RuO_2$) nanotubes with controlled dimensions can be synthesized using facile electrochemical means and anodic aluminum oxide (AAO) templates. $RuO_2$ nanotubes were formed using a cyclic voltammetric deposition technique and an aqueous plating solution composed of $RuCl_3$. Linear sweep voltammetry (LSV) was used to determine the effective electrochemical oxidation potential of $Ru^{3+}$ to $RuO_2$. The length and wall thickness of $RuO_2$ nanotubes can be adjusted by varying the range and cycles of the electrochemical cyclic voltammetric potentials. Thick-walled $RuO_2$ nanotubes were obtained using a wide electrochemical potential range (-0.2~1 V). In contrast, an electrochemical deposition potential range from 0.8 to 1 V produced thin-walled and longer $RuO_2$ nanotubes in an identical number of cycles. The dependence of wall thickness and length of $RuO_2$ nanotubes on the range of cyclic voltammetric electrochemical potentials was attributed to the distinct ionic diffusion times. This significantly improves the ratio of surface area to mass of materials synthesized using AAO templates. Furthermore, this study is directive to the controlled synthesis of other metal oxide nanotubes using a similar strategy.

• Korean Journal of Materials Research
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• v.20 no.1
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• pp.25-30
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• 2010

Si nanowire/multiwalled carbon nanotube nanocomposite arrays were synthesized. Vertically aligned Si nanowire arrays were fabricated by Ag nanodendrite-assisted wet chemical etching of n-type wafers using $HF/AgNO_3$ solution. The composite structure was synthesized by formation of a sheath of carbon multilayers on a Si nanowire template surface through a thermal CVD process under various conditions. The results of Raman spectroscopy, scanning electron microscopy, and high resolution transmission electron microcopy demonstrate that the obtained nanocomposite has a Si nanowire core/carbon nanotube shell structure. The remarkable feature of the proposed method is that the vertically aligned Si nanowire was encapsulated with a multiwalled carbon nanotube without metal catalysts, which is important for nanodevice fabrication. It can be expected that the introduction of Si nanowires into multiwalled carbon nanotubes may significantly alter their electronic and mechanical properties, and may even result in some unexpected material properties. The proposed method possesses great potential for fabricating other semiconductor/CNT nanocomposites.

• The Korean Journal of Zoology
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• v.22 no.4
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• pp.141-152
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• 1979

Feline leukemia virus DNA polymerase was purified by ion-exchange and nucleic acid affinity chromatographies. The enzyme consists of a single polypeptide chain of approximately 72, 000 molecular weight as determined by both of a glycerol density gradient centrifugation and SDS-polyacrylamide gel electrophoresis. The preferred divalent cation for DNA synthesis is $Mn^2+$ on a variety of template-primers, and its optimum concentration appears to be significantly lower than reported results of other mammalian type-C viral enzymes. The divalent cation requirement for maximum activity of RNase H is similar to those of DNA polymerase. Both DNA polymerase and RNase H activities appear to reside on the same molecule as demonstrated by the copurification of both activities through various purification steps. An additional RNase H without detectible polymerase activity was generated by a limited chymotrypsin digestion. This RNase H activity was inhibited equally effectively as RNase H in the intact reverse transcriptase by antisera prepared against reverse transcriptase of feline leukemia virus. Neutralization and binding test showed that antibody binding to reverse transcriptase molecule did not completely inhibit the polymerase activity.

• Korean Journal of Materials Research
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• v.25 no.3
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• pp.144-148
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• 2015

Cubic mesocrystal $CeO_2$ was synthesized via a hydrothermal method with glutamic acid ($C_5H_9NO_4$) as a template. The XRD pattern of a calcined sample shows the face-centered cubic fluorite structure of ceria. Transmission electron microscopy (TEM) and the selected-area electron diffraction (SAED) pattern revealed that the submicron cubic mesocrystals were composed of many small crystals attached to each other with the same orientation. The UV-visible adsorption spectrum exhibited the red-shift phenomenon of mesocrystal $CeO_2$ compared to commercial $CeO_2$ particles; thus, the prepared materials show tremendous potential to degrade organic dyes under visible light illumination. With a concentration of a rhodamine B solution of 20 mg/L and a catalyst amount of 0.1 g/L, the reaction showed higher photocatalytic performance following irradiation with a xenon lamp (${\geq}380nm$). The decoloring rate can exceed 100% after 300 min.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.270-273
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• 2012

x mol% (x = 0 ~ 20) Na2CO3 excess Bi2.5Na3.5Nb5O18 (BNN) particles were synthesized using molten salt as a flux. The secondary phases were observed at stoichiometric ratio of BNN precursors and their intensity decreased with increasing Na contents. The results of SEM images showed that all particles existed in a platelet shape and the particle increased in size with higher increasing Na contents. Plate-like NaNbO3 particles were developed using BNN precursor obtained by a topochemical microcrystal conversion. XRD analysis of NaNbO3 particles showed that a single perovskite phase and the intensity of (h00) peaks increased with increasing Na contents in BNN precursor. SEM images showed that the size of plate-like NaNbO3 was significantly changed by controlling Na contents in BNN precursors.

• Analytical Science and Technology
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• v.19 no.3
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• pp.218-225
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• 2006

A molecularly imprinted polymer (MIP) was synthesized by radiation-induced polymerization (RIP), where the ferulic acid was used as a template molecule, 4-vinylpyridine as a monomer and ethylene glycoldimethacrylate (EGDMA) as a cross-linking monomer. The MIP was packed in a glass column using a slurry method for use in medium pressure liquid chromatography (MPLC). The MPLC column was tested for separation and purification of ferulic acid from the rice oil. When repeated three times, the MPLC separation/purification yielded the ferulic acid with the purity higher than ~99%. The chemiluminescence of the luminal (5-amino-2,3-dihydro-1,4-phtalazinedione) measured on a potato disc slide (5.0 mm thick) was enhanced in the presence of ferulic acid, while, without the ferulic acid, the chemiluminescence of luminol on the potato slice disc was not observed, which suggests the ferulic acid obtained from the rice oil can be useful for immunoassay.

• Clean Technology
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• v.30 no.2
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• pp.123-133
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• 2024

Zeolite template carbon (ZTC) was synthesized as an adsorbent to remove low-concentration CH₄ from the atmosphere. The synthesis of ZTC was performed using CH₄ and C₂H₂ as carbon precursors and their impact on adsorption was investigated. ZTC was also synthesized using Y zeolite ion-exchanged with CaCl₂ and LiCl as templates to investigate the effect of using metals in ion exchange. The comparison of the carbon precursors revealed that C₂H₂ had a higher carbon yield than CH₄. The synthesized ZTC exhibited developed micropores due to carbon deposition deep inside the micropores of the zeolite template. The kinetic diameter of C₂H₂ (0.33 nm) is smaller than that of CH₄ (0.38 nm), which allowed for its deposition. The study compared metal precursors used for ion exchange and confirmed that the CaCl₂-based ZTC developed more micropores compared to the LiCl-based ZTC. The ion-exchanged Ca inhibited pore blocking by the carbon precursor, allowing it to enter the pores. The ability of synthesized ZTC to adsorb N₂ and CH₄ at 298 K was investigated. The results showed that CH₄ had a higher overall adsorption amount than N₂. The sample synthesized using C₂H₂ and CaY exhibited the highest N₂ and CH₄ adsorption capacity. However, the sample synthesized with CH₄ had the highest CH₄/N₂ gas uptake ratio, which is a crucial factor in designing an adsorption process. The observed difference was likely caused by the underdevelopment of ultrafine pores that are associated with N₂ adsorption. This resulted in a reduction of N₂ adsorption, leading to an increase in CH₄/N₂ separation.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.173-177
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• 2011

In this study, the formation of $AlPO_4$-type porous materials from alum sludge was investigated. The materials were synthesized by the reaction of aluminum hydroxide and phosphoric acid with an organic template. Cationic surfactant, natural humic acid, and amino acids were used for the organic template. The residual organic templates were removed by calcination at $600^{\circ}C$ in the air. Powder X-ray diffraction patterns showed the charicteristic patterns of the $AlPO_4$-type porous materials. The morphology of the material was examined using a scanning electron microscopy. The coordination environment of $Al^{3+}$ ion was investigated by $^{27}Al$ MAS NMR technique. Both tetrahedrally and octahedrally coordinated$Al^{3+}$ ions were found in the as-synthesized samples while all $Al^{3+}$ ions were tetrahedrally coordinated in the calcined products. The development of mesopore in the solid material was confirmed by the measurement of BET specific surface area. Finally, they were used for removal of toxic formaldehyde from the air and the formaldehyde molecules were adsorbed on the surface of pores. In conclusion, $AlPO_4$-type porous materials from alum sludge might be applicable in the removal of toxic volatile organic compounds from the air.

• Polymer(Korea)
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• v.32 no.2
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• pp.138-142
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• 2008

Molecularly imprinting technology is an effective method to prepare a synthetic material with a high selectivity to a target molecule. In this study, a molecularly imprinted polymer (MIP) was synthesized via UV-polymerization using theophylline and UV-curable polyester-acrylate resin as a template molecule and a crosslinker, respectively. To elucidate the effects of functional monomer type on the performance of the MIP, each MIP was synthesized using mathacrylic acid, acrylic acid, and acryl amide as functional monomers. Each MIP showed higher rebinding capacity to theophylline than its corresponding non-imprinted polymer (NIP). The MIP synthesized using mathacrylic acid as a functional monomer showed the highest rebinding capacity to theophylline. The selectivity of the MIP was investigated using a solution with caffeine having a very similar structure to theophylline. The binding performance of the MIP to theophylline decreased when distilled water was used as a solvent, which has more polarity than chloroform.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.31-40
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• 2012

In this paper, we propose a method of synthesizing faces of a user and an animation character using a 3D face model. The suggested method first receives two orthogonal 2D face images and extracts major features of the face through the template snake. It then generates a user-customized 3D face model by adjusting a generalized face model using the extracted facial features and by mapping texture maps obtained from two input images to the 3D face model. Finally, it generates a user-customized animation character by synthesizing the generated 3D model to an animation character reflecting the position, size, facial expressions, and rotational information of the character. Experimental results show some results to verify the performance of the suggested algorithm. We expect that our method will be useful to various applications such as games and animation movies.