• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.279-282
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• 2010

스티로폼샌드위치패널은 건식공법의 시공편리성, 경제적인 공사비용, 뛰어난 단열성능으로 공장이나 창고건축물을 중심으로 많이 사용되고 있다. 그러나 스티로폼의 여러 가지 장점에도 불구하고 화재에 취약한 단점이 있어 최근 난연성능이 보완된 난연스티로폼패널의 사용이 증가하고 있다. 최근 건축현장에서, 가짜 난연스티로폼패널 사용이 문제되고 있으나 난연성능의 현장 확인에 어려움이 있고 콘칼로리미터 등의 난연성능평가에 시간과 비용이 소요된다. 본 연구에서는 콘칼로리미터를 통해 난연성능이 확보된 난연 스티로폼패널의 심재와 일반스티로폼패널 심재를 대상으로 근-적외선 분광분석을 수행하여 난연성능의 유무에 따라 상이하게 나타나는 고유스펙트럼 흡수를 측정하였다. 각 제품마다 측정된 고유스펙트럼은 통계처리를 통하여 난연스티로폼의 진위여부를 현장에서 구별할 수 있음을 확인하였으며, 비용효율이 높은 현장평가방법으로의 적용이 가능함을 실험을 통해 입증하였다.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.109-116
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• 2018

$Eu_2(SO_4)_3$ was synthesized by chemical precipitation method and the crystal structure was determined by Rietveld analysis. The compound crystallizes in monoclinic space group C2/c. In the air environment, $Eu_2(SO_4)_3$ is stable up to $670^{\circ}C$. The sample of $Eu_2(SO_4)_3$ was examined by Raman, Fourier-transform infrared absorption and luminescence spectroscopy methods. The low site symmetry of $SO_4$ tetrahedra results in the appearance of the IR inactive ${\nu}_1$ mode around $1000cm^{-1}$ and ${\nu}_2$ modes below $500cm^{-1}$. The band intensities redistribution in the luminescent spectra of $Eu^{3+}$ ions is analyzed in terms of the peculiarities of its local environment.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.703-708
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• 2001

K2NiF4-type organic-based perovskites of the (C4H9NH3)2FexPb1-xCl4 (x=0.00, 0.25, 0.50, and 0.75) system have been synthesized using a low-temperatu re solution method under a flowing argon gas. When stoichiometric butylamine, iron chloride, and lead chloride are mixed, a yellow solution are obtained from slow cooling of 90 to -10 $^{\circ}C.$ The final product is a plate-like yellow crystal. The X-ray crystallographic analysis has been carried out using XRD in the range of $5^{\circ}{\leq}$ 2${\theta}$ ${\leq}80^{\circ}.$ The local symmetry around the absorbing Pb atom of the samples has been determined by the EXAFS spectroscopic study. The crystals assign to orthorhombic system by the XRD analysis. The FT-IR spectra are analyzed in the range of 600 to 3300 cm-1 . DSC and TGA are measured to detect thermal stability between 30 and 300 $^{\circ}C.$ Two endothermic peaks are detected in all samples. The electrical conductivity has been measured using the four-probes technique for the (C4H9NH3)2FexPb1-xCl4 system in 300-460 K. Photoluminescence phenomenon was also investigated at room-temperature.

• Bulletin of the Korean Chemical Society
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• v.21 no.7
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• pp.679-684
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• 2000

The Sr2Co0.5Nb(Ta)0.5O4 and Sr3CoNb(Ta)O7 compounds, both with Ruddlesden-Popper structures, have been synthesized by the ceramic method at $1150^{\circ}C$ under atmospheric pressure. The crystallographic structure of the compounds was assigned to the tetr agonal system with space group 14/mmm by X-ray diffraction(XRD) Rietveld refinement. The reduced lattice volume and lattice parameters increased as the Ta with 5d substitutes for the Nb with 4d in the compounds. The Co/Nb(Ta)O bond length has been determined by X-ray absorption spectroscopic(EXAFS/XANES) analysis and the XRD refinement. The CoO6,octahedra were tetragonally distorted by elongation of Co-O bond along the c-axis. The magnetic measurement shows the compounds Sr2Co0.5Nb(Ta)0.5O4 and Sr3CoNb(Ta)O7 have paramagnetic properties and the Co ions with intermediate spin sates between high and low spins in D4h symmetry. All the compounds showed semiconducting behavior whose electrical conductivity increased with temperature up to 1000 K. The electrical conductiviy increased and the activation energy for the conduction decreased as the number of perovskite layers increased in the compounds with chemical formula An+1BnO3n+1.

• Polymer(Korea)
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• v.38 no.1
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• pp.49-53
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• 2014

A novel monomeric UV-absorber was prepared by the reaction of 2,4-dihydroxybenzophenone with N-4-chlorocarbonylphenylmaleimide in the presence of triethylamine. This reactive maleimide was grafted onto polypropylene (PP) by the thermal melt-processing in a mini-max-moulder. IR spectroscopic method was used for the quantitative determination of the extent of grafting of monomeric maleimide. To find the optimal reaction conditions, the dependence of reaction temperature and time and the concentration of monomeric UV-absorber was investigated on the grafting yields. The photooxidative effect of the grafted PP was evaluated in the weatherometer comparing to the PP mixed with UV-absorbers using the carbonyl index of IR spectrum. The grafted PP showed an excellent anti-photooxidative effect.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.527-531
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• 2001

Two triterpenoids, 24-methylene-3,4-seco-cycloart-4(28)-en-3-oic acid (1) and 3-oxo-$9{\beta}$-lanosta-7,22Z,24-trien-26,23-olive (6) were isolated from Abies koreana, together with $\beta$-sitosterol (2), maltol (3), ${\beta}-sitosterol-O-{$\beta}-D-glucoside$ (4), and hexacosylferulate (5). The structures of the compounds were established based on the spectroscopic data. The cytotoxic activities of triterpenoids have been evaluated using the sulforhodamine B (SRB) method. Compound 1 showed moderate cytotoxicities against human lung carcinoma (A549), ovarian carcinoma (SK-OV-3), malignant melanoma (SK-MEL-2), and colon carcinoma (HCT-15) cell lines.

• Natural Product Sciences
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• v.25 no.3
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• pp.233-237
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• 2019

Three Diels-Alder type adducts, guangsangon E (1), chalcomoracin (2) and sorocein I (3) were isolated from hairy root cultures of Morus macroura. The structures of the isolated compounds (1-3) were determined by spectroscopic method (NMR and MS), and spectral comparison to literature. Cytotoxic activities of the isolated compounds (1 - 3) were investigated against P-388 murine leukemia cell line. Guangsangon E (1) showed the most potent cytotoxicity against P-388 murine leukemia cell line with $IC_{50}$ value of $2.75{\pm}0.32{\mu}g/mL$. To the best of our knowledge, guangsangon E (1) and sorocein I (3) were reported for the first time from the tissue cultures of M. macroura.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.37.2-37.2
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• 2018

We present the results from a spectroscopic survey of the nearby galaxy cluster Abell 2107 at z=0.04 that has been known as a rotating cluster. By combining 978 new redshifts from the MMT/Hectospec observations with the data in the literature, we construct a large sample of 1968 galaxies with measured redshifts at R<60', which results in high (80%) and spatially uniform completeness at $m_{r,Petro,0}<19.1$. We use this sample to study the global rotation of the cluster and its connection to the large-scale structures in the universe. We first apply the caustic method to the sample and identify 285 member galaxies in Abell 2107 at R<60'. We then measure the rotation amplitude and the position angle of rotation axis. The member galaxies show strong global rotation at R<20' ($V/{\sigma}{\sim}0.60-0.70$) with a significance of >3.8 ${\sigma}$, which is confirmed by two independent methods. The rotation becomes weaker in outer regions. We find at least four filamentary structures at $R<30h^{-1}Mpc$ smoothly connected to the cluster galaxies, which can suggest that the global rotation of the cluster is induced by the inflow of galaxies from the surrounding large-scale structures in the universe.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.33.2-33.2
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• 2018

Fossil galaxy cluster has a dominant central elliptical galaxy (${\Delta}M12$ >2 in 0.5Rvir) embedded in highly relaxed X-ray halo, which indicates dynamically stable and passively evolved system. These features are expected as a final stage of the cluster evolution in the hierarchical structure formation paradigm. It is known that Abell 2261(A2261 hereafter) is classified as a fossil cluster, but has unusual features such as a high central X-ray entropy (i.e., non-cool core system), which is not expected in normal fossil clusters. We perform a kinematic study with a spectroscopic data of 589 galaxies in the A2261 field. We define cluster member galaxies using the caustic method and discover a new second bright galaxy at ~1.5 Rvir (nearly the splash-back region). It implies the current fossil state of the cluster can break in the near future. In addition, with three independent substructure finding methods, we find that A2261 has many substructures within 3 Mpc from the center of the cluster. These findings support that A2261 is not in a dynamically stable state. We argue that A2261 is in a transitional phase of dynamical evolution of the galaxy cluster and maybe previously defined fossil cluster does not mean the final stage of the evolution of galaxy clusters.

• Journal of the Korean Chemical Society
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• v.65 no.3
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• pp.203-208
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• 2021

As part of our attempt to discover novel active compounds against multi-drug resistant pathogens, we hereby report two new complexes of iron(III) with formulae: [Fe(L₁)₂(H₂O)₂]Cl₃ and [Fe(L₁)₂(L₂)(H₂O)]Cl₂ where L₁ = 1,10-phenanthroline (C₁₂H₈N₂) and L₂ = guanide (C₅H₄N₅O^-). The synthesized complexes were characterized using spectroscopic analysis (ESI-MS, ICP-OES, FT-IR, and UV-Vis), cyclic voltammetry, CHN analysis, gravimetric chloride determination, melting point determination, and conductance measurement. Octahedral geometries are assigned to both complexes. In vitro antibacterial activity was tested on two Gram-positive (Staphylococcus aureus, Streptococcus epidermidis) and two Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria using the disc diffusion method. The complexes demonstrated appreciable activity against these pathogens. Interestingly, the [Fe(L₁)₂(L₂)(H₂O)]Cl₂ complex manifested a higher degree of inhibition against the drug-resistant Gram-negative bacteria than the commercially available drug, namely erythromycin.