• Journal of the Optical Society of Korea
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• v.14 no.3
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• pp.282-285
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• 2010

We printed a one-dimensional array of metallic wires and a two-dimensional array of metallic split ring resonators on a photo-paper by using a high-dots-per-inch resolution printer and an ink with silver nano-particles. The printed sample sizes are $1.0{\times}1.0cm^2$. The transmission measured by a terahertz time domain spectroscopy system shows that the arrays of wires and split ring resonators could act as polarizers and band-stop filters, respectively, in a terahertz frequency region.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.102-102
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• 2010

One or two-dimensional nanostructures such as nanowires or nanomats have been widely uses as building blocks for nanoscale electronic devices. Nanofiber is one of sub-category of nano structures, it is easy to make nano-sized fiber by electrospinning technique. Nanofiber has large surface area as compared with their volume, it could be widely applied to many areas easily. Electrospinning technique is easy to control their structures and morphology safely and cost-effectively. We made nano-rings as a model of one dimensional nanostructures by electrospinning technique. To our knowledge, there were no reports on the preparation and investigation of alumina nano-rings by electrospinning technique. In this study, aluminum oxide nano-rings were produced after electospinning and calcination. The synthesized aluminum oxide nano-rings were characterized by scanning electron microscopy (SEM) to identify the morphology and the diameter of the ring, X-ray diffraction (XRD) to verify the crystallinity of the aluminum oxide, and X-ray photoelectron spectroscopy (XPS) for investigation of the chemical nature of the synthesized nano-rings.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.321-326
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• 2016

Two new polymeric complexes, [Zn(dpa)(pyz)_0.5]_n (1; dpa = diphenate and pyz = pyrazine) and [Mn₃(bpdc)₃(py)₄]_n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa²⁻ (1) and bpdc²⁻(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

• Journal of Powder Materials
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• v.18 no.6
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• pp.538-545
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• 2011

This study shows that catalytic activity of bimetallic RhPt nanoparticle arrays under CO oxidation can be tuned by varying the size and composition of nanoparticles. The tuning of size of RhPt nanoparticles was achieved by changing concentration of rhodium and platinum precursors in one-step polyol synthesis. Two-dimensional RhPt bimetallic nanoparticle arrays in different size and composition were prepared through Langmuir-Blodgett thin film technique. CO oxidation was carried out on these two-dimensional nanoparticle arrays, revealing higher activity on the smaller nanoparticles compared to the bigger nanoparticles. X-ray photoelectron spectroscopy (XPS) results indicate the preferential surface segregation of Rh compared to Pt on the smaller nanoparticles, which is consistent with the thermodynamic analysis. Because the catalytic activity is associated with differences in the rates of $O_2$ dissociative adsorption between Pt and Rh, this paper suppose that the surface segregation of Rh on the smaller bimetallic nanoparticles is responsible for the higher catalytic activity in CO oxidation. This result suggests a control mechanism of catalytic activity via synthetic approaches of colloid nanoparticles, with possible application in rational design of nanocatalysts.

• Macromolecular Research
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• v.14 no.2
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• pp.166-172
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• 2006

This is a short review article of our recent studies on the ATP-induced, allosteric conformational transition of the chaperonin GroEL complex by solution X-ray scattering. We used synchrotron X-ray scattering with a two-dimensional, charge-coupled, device-based X-ray detector to study (1) the specificity of the chaperonin GroEL for its ligand that induced the allosteric transition, and (2) the identification of the allosteric transition of GroEL in its complicated kinetics induced by ATP. Due to the dramatically increased sensitivity of the X-ray scattering technique based on the use of the two dimensional X-ray detector and synchrotron radiation, different allosteric conformational states of GroEL populated under different conditions were clearly distinguished from each other. It was concluded that solution X-ray scattering is an extremely powerful tool for investigating the equilibrium and kinetics of cooperative conformational transitions of oligomeric protein complex, especially when combined with other spectroscopic techniques such as fluorescence spectroscopy.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.302-302
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• 2011

Fabrications of metal-organic hybrid networks attracted much attention due to possible applications in gas storages, heterogeneous catalyses, information storages, and opto-electronic devices. One way to construct three-dimensional hybrid structures is to make the arrays of planar or linear metal-organic hybrid structures which are linked through electrostatic interactions. As a model study, we fabricated the arrays of one-dimensional hybrid chains and investigated inter-chain interactions between adjacent hybrid chains using scanning tunneling microscopy (STM) and spectroscopy (STS) on Ag(111). Brominated anthracene molecules were used to grow the arrays of hybrid chains on Ag(111). We proposed atomic models for the observed structures. Linear chains are made of repetition of Ag-anthracene units. Br atoms are attached to anthracene molecules through Br-H structures which mediate inter-chain interactions. Two different apparent heights were observed in anthracene molecules. Molecules having a Br-H connection look brighter than those with two connections due to electronic effect. When a chain is laterally manipulated with STM tip, Br atoms move together with the chain implying that Br-H inter-chain interactions are quite strong.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.98-99
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• 2012

Deposition of thin films using magnetron sputtering plasmas is a well-developed, classical technology. However, detailed investigations using advanced diagnostics are insufficient in magnetron sputtering, in comparison with plasma-aided dry etching and plasma-enhanced chemical vapor deposition. In this talk, we will show examples of diagnostic works on magnetron sputtering employing metal targets. Diagnostic methods which have fine spatial resolutions are suitable for magnetron sputtering plasmas since they have significant spatial distributions. We are using two-dimensional laser-induced fluorescence spectroscopy, in which the plasma space is illuminated by a tunable laser beam with a planer shape. A charge-coupled device camera with a gated image intensifier is used for taking the picture of the image of laser-induced fluorescence formed on the planer laser beam. The picture of laser-induced fluorescence directly represents the two-dimensional distribution of the atom density probed by the tunable laser beam, when an intense laser with a relatively wide line-width is used. When a weak laser beam with a relatively narrow linewidth is used, the laser-induced fluorescence represents the density distribution of atoms which feel the laser wavelength to be resonant via the Doppler shift corresponding to their velocities. In this case, we can obtain the velocity distribution function of atoms by scanning the wavelength of the laser beam around the line center.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1150-1154
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• 2003

The reactions of [Ni(L)(H₂O)₂]Cl₂ (L = 2,5,9,12-tetramethyl-1,4,8,11-tetraazacyclotetradecane) with terephtalate (tp) and 2,5-pyridinedicarboxylate (pdc) generate one-dimensional nickel(II) complexes, [Ni(L)(H₂O)₂](tp) · ₄H₂O (1) and [Ni(L)(H₂O)₂](pdc)·₄H₂O (2). The structures have been characterized by X-ray crystallography, magnetic susceptibility and spectroscopy. The crystal structures of 1 and 2 show a distorted octahedral coordination geometry around the Ni(II) ion, with secondary amines of the macrocycle and two water molecules at the trans position. Complexes 1 and 2 display the one-dimensional hydrogen-bonded infinite chains. The magnetic behavior of all compounds exhibits weak interchain antiferromagnetic interactions with J values of -1.09(3) for 1 and -1.14(2) cm-1 for 2.

• Journal of Powder Materials
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• v.23 no.4
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• pp.270-275
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• 2016

We report on an all-solution-processed hydrothermal method to control the morphology of ZnO nanostructures on Si substrates from three-dimensional hemispherical structures to two-dimensional thin film layers, by controlling the seed layer and the molar contents of surfactants during their primary growth. The size and the density of the seed layer, which is composed of ZnO nanodots, change with variation in the solute concentration. The ZnO nanodots act as heterogeneous nucleation sites for the main ZnO nanostructures. When the seed layer concentration is increased, the ZnO nanostructures change from a hemispherical shape to a thin film structure, formed by densely packed ZnO hemispheres. In addition, the morphology of the ZnO layer is systematically controlled by using trisodium citrate, which acts as a surfactant to enhance the lateral growth of ZnO crystals rather than a preferential one-dimensional growth along the c-direction. X-ray diffraction and energy dispersive X-ray spectroscopy results reveal that the ZnO structure is wurtzite and did not incorporate any impurities from the surfactants used in this study.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1294-1298
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• 2007

Two new compounds lanast-5,8-dien-3β-ol-27-oic acid-3β-D-glucopyranosyl (4'-1'')-10'',11''-dimethoxy anthracene (1), 2-methoxy-6-(n-nonacontan-5'',6''-dionyl)-11-hydroxy-13-methyl-11β-D-rhamnopyranoside anthracene (2) have been isolated from the hairy root cultures of Catharanthus roseus. Their structures have been elucidated with the help of 500 MHz NMR using one- and two-dimensional NMR in combination with IR, EI/MS, FAB/MS and HRFABMS spectroscopy.