• Polymer(Korea)
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• v.25 no.3
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• pp.421-426
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• 2001

11-Aminododecanoic acid, to insert the functional group of -COOH reacted with the end group of poly($\varepsilon$-caprolactone) diol, and cetyltrimethylammonium bromide (CTMA), to increase the d-spacing of Montmorillonite (MMT), were intercalated into $Na^+;_-$MMT. The modified MMT was reacted with poly(${varepsilon}-caprolactone$) diol ($M_n{=2000$) in THF solution at $80^{\circ}C$ for 4 hrs. After reaction, poly(${varepsilon}-caprolactone$) ($M_n{=80000$) was mixed into the solution for 12 hrs. To prepare the PCL/clay nanocomposite film this solution was cast into the silicon mold at $60^{\circ}C$ in vacuum oven for 6 hrs. From the results of XRD and TEM, it was found that the exfoliated PCL/clay nanocomposite were prepared. The effects of the amount of MMT on the mechanical properties and thermal properties of PCL/clay nanocomposites have been investigated by tensile tester and DSC. Because the MMT was dispersed homogeneously in PCL matrix, the Young's modulus of the nanocomposite were found to be excellent. However, MMT dispersed in PCL matrix had almost no effect on the tensile strength of the composites. The crystallization temperature of PCL increased in proportion to 3 wt% MMT in the PCL matrix.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.537-542
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• 2005

It was proposed that Ru(II)[(1,10-phenanthroline)$_2$dipyrido[3,2-a:2',3'-c]phenazine ([Ru(phen)$_2$DPPZ]$^{2+}$)complexes and 4',6-diamidino-2-phenylindole (DAPI) simultaneously bind to poly[d(A-T)$_2$] (Biophysics. J. 2003, 85, 3865). Förster type resonance energy transfer from excited DAPI to [Ru(phen)2DPPZ]$^{2+}$ complexes was observed. In this study, we synthesized $\Delta$- and $\wedge$-[Ru(phenanthroline)$_2$dipyrido[3,2-a:2’3’c]6-azaphenazine] ([Ru(phen)$_2$DPAPZ]$^{2+}$) at which the DNA intercalating ligand DPPZ was replaced and we studied its binding properties to poly[d(A-T)$_2$] in the presence and absence of DAPI using polarized spectroscopy and fluorescence techniques. All the spectroscopic properties of the [Ru(phen)$_2$DPAPZ]$^{2+}$-poly[d(A-T)$_2$] complex were the same in the presence and absence of DAPI that blocks the minor groove of polynucleotide, suggesting both $\Delta$- and $\wedge$-[Ru(phen)$_2$DPAPZ]$^{2+}$ complexes are located at the major groove of poly[d(A-T)2]. On the other hand, in contrast with [Ru(phen)$_2$DPPZ]$^{2+}$, both $\Delta$- and $\wedge$-[Ru(phen)$_2$DPAPZ]$^{2+}$ exhibited almost twice the efficiency in the fluorescence quenching of DAPI that binds at the minor groove of poly[d(A-T)$_2$]. This observation indicates that the efficiency of the Förster type resonance energy transfer can be controlled by a small change in the chemical structure of the intercalated ligand.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.822-827
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• 2017

Mg/Al layered double hydroxide with two-dimensional (2D) nanostructures was synthesized by a hydrothermal technique. The morphology and aspect ratio of $Mg_4Al_2(OH)_{14}3H_2O$ were controlled by the concentration and kinds of the hydrolysis agent, and temperature. The aspect ratio of $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides with the 2D hexagonal crystal structure was tailored from about 12.6 to about 45.7. The intercalated $CO{_3}^{2-}$ anions of the synthesized 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides were exchanged to $NO_3{^-}$ anions. The bulk 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides with the increased space between two layers due to the anion exchange were exfoliated in a formamide solution. The aspect ratio of the exfoliated 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides increased to 570.3.

• BMB Reports
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• v.35 no.4
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• pp.389-394
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• 2002

$[Ru(bpy)_2(dppz)]^2+$ (bpy=2,2'-bipyfidine, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuBD), a long-lifetime metal-ligand complex, displays favorable photophysical properties. These include long lifetime, polarized emission, but no significant fluorescence from the complex that is not bound to DNA. To show the usefulness of this luminophore (RuBD) for probing the bending and torsional dynamics of nucleic acids, its intensity and anisotropy decays when intercalated into supercoiled and relaxed pTZ18U plasmids were examined using frequency-domain fluorometry with a blue light-emitting diode (LED) as the modulated light source. The mean lifetimes for the supercoiled plasmids (< $\tau$ >=148 ns) were somewhat shorter than those for the relaxed plasmids (< $\tau$ >=160 ns). This suggests that the relaxed plasmids were shielded more efficiently from water. The anisotropy decay data also showed somewhat shorter slow rotational correlation times for supercoiled plasmids (288 ns) than for the relaxed plasmids (355 ns). The presence of two rotational correlation times suggests that RuBD reveals both the bending and torsional motions of the plasmids. These results indicate that RuBD can be useful for studying both the bending and torsional dynamics of mucleic acids.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.489-493
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• 2013

The most common carbonaceous anode materials of lithium ion batteries (natural graphite, artificial graphite, hard carbon, and mesocarbon microbeads) were utilized as an electrode in lithium ion capacitors. It could be able to enhance the energy density of capacitors due to the intercalation of lithium ion. In this work, the properties of capacitors using the symmetric electrode were measured by organizing coin cell typed capacitors. Also, we made other capacitors having pre-intercalated lithium ions at one side of the electrode. The results of electrochemical measurements for these capacitors show that the storage capacitance was appeared. In other words, if the migration of lithium ions is supplied continuously in the electrolytes, lithium ions can be diffused into the carbonaceous materials. And it results in the improvement of capacitance compared to only using symmetric carbonaceous electrodes. Also, we conducted the same measurement with graphene oxide having a the large specific area in the same condition. Herein, we recognized that the large specific area is extremely important for supercapacitors.

• The Journal of the Petrological Society of Korea
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• v.5 no.1
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• pp.84-88
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• 1996

Pb isotope composition is analyzed from the rock chips of marbles intercalated between gneisses of Muju area and it shows very large variation ($^{206}Pb/^{204}Pb$=23.74~4142, $^{207}Pb/^{204}Pb$=16.32~18.43, $^{208}Pb/^{204}Pb$=36.42~39.75). The data points form well defined positive relationship on $^{206}Pb/^{204}Pb$ vs $^{207}Pb/^{204}Pb$ plot, which corresponds to $1.99{\pm}0.10$($2{\sigma}$) Ga. This age is very similar to the formation ages of the granitic gneisses from Buncheon and Cheondongri (Tanyang), and suggests that the fairly large volume of Sobaeksan Massif suffered regional metamorphism at this time. It is suggested that the most parts of Korean peninsula including Kyeonggi and Sobaeksan Massifs were very close each other and experienced a regional metamorphism together about 2.0 Ga ago from the fact that galenas from whole Korean Peninsula except Kyeongsang Basin and metamorphic rocks from Kyeonggi Massif also reveal a similar slope corresponding 2.0 Ga on Pb-Pb isotope plot.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.497-507
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• 1998

The localizations and morphological characteristics of immunoreactive cells for prolactin(PRL) and growth hormone(GH) antisera were studied with double immunohistochemistry in the adenohypophysis of the Korean native goat. PRL immunoreactive cells(mammotropes) and GH immunoreactive cells(somatotropes) were present in the pars distalis and pars tuberalis, but not in the pars intermedia. A few cells were stained with both PRL and GH antisera (somatomammotropes). The possessional percentages of mammotropes, somatotropes and somatomammotropes were 37.0%, 32.6%, 1.0% in females and 35.6%, 32.6%, 1.1% in males, respectively. Mammotropes were oval or round in shape, and $10{\sim}20{\mu}m{\times}17{\sim}25{\mu}m$ in size. These cells were distributed throughout the pars distalis, but were more abundant on the dorsal part adjacent to the hypophyseal cavity and along the lateral and ventral peripheral regions. Somatotropes were elliptical, triangular or polygonal in shape, and $8{\sim}17{\mu}m{\times}17{\sim}18{\mu}m$ in size. The distribution pattern of somatotropes was similar to that of mammotropes. Some somatomammotropes were intercalated between clusters of mammotropes while the others were dispersed independently among the secretory cells.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.715-725
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• 1994

The ultrastructural investigations of the parotid gland of Korean native goat were carried out by transmission electron microscopy. The results were as follows; 1. The acini of parotid gland were composed of light and dark acinar cells. 2. In the light acinar cells, the secretory granules were classified into three types according to their electron densities and dense bodies. One type of granules was low electron density and had no dense bodies. Another type was low electron density and had dense bodies, and the other type was low electron density and had granular dense bodies. 3. The secretory granules of dark acinar cells showed high electron density and were also calssified into three types by dense bodies as the same way as in the light acinar cells. 4. The intercalated ducts consisted of simple cuboidal epithelium. The nuclei of epithelial cells were oval or round form, located at the central part, and had infolding nuclear membranes and one or two nucleoli. 5. The cells of both of the striated and excretory ducts were composed of light cells, dark cells, specific light cells and basal cells. 6. The nerve terminals were distinguished into two types. One had large granular synaptic vesicles, and another had small agranular synaptic vesicles.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.620-624
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• 2003

LiCo$_{y}$Mn$_{2-y}$O$_4$ samples were synthesized by calcining a mixture of LiOH.$H_2O$, MnO$_2$ (CMD) and CoCO$_3$ calcining at 40$0^{\circ}C$ for 10 h and then calcining twice at 75$0^{\circ}C$ for 24 h in air with intermediate grinding. All the synthesized samples exhibited XRD patterns for the cubic spinel phase with a space group Fd(equation omitted)m. The electrochemical cells were charged and discharged for 30 cycles at a current density 600 $mutextrm{A}$/$\textrm{cm}^2$ between 3.5 and 4.3 V. As the value of y increases, the size of particles becomes more homogeneous. The first discharge capacity decreases as the value of y increases, its value for y=0.00 being 92.8 mAh/g. The LiMn$_2$O$_4$ exhibits much better cycling performance than that reported earlier. The cycling performance increases as the value of y increases. The efficiency of discharge capacity is 98.9％ for y=0.30. The larger lattice parameter for the smaller value of y is related to the larger discharge capacity. The more quantity of the intercalated and the deintercalated Li in the sample with the larger discharge capacity brings about the larger capacity fading rate.ate.

• Journal of the Korean earth science society
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• v.30 no.1
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• pp.33-39
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• 2009

This paper presents the occurrence and characteristics of the basaltic andesite-siltstone peperite in the lower part of the Gyehwari Formation (Cretaceous), Buan-gun, Jeonbuk province, SW Korea. The peperite is associated with tabular basaltic andesite body, concordantly intercalated with red siltstone and silty sandstone interbeds of floodplain facies. Development of the peperite along the upper margin of the andesite and its textural transition from a dispersed blocky type inward into a closely packed type collectively indicate an intrusive origin (?sill) of the andesite. Magma intrusion and subsequent peperite formation suggest an active syndepositional volcanism since the early stage of evolution of the Gyehwa Basin. The andesite is dated at Late Cretaceous (Santonian) by K-Ar whole-rock radiometric method.