• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2508-2512
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• 2012

Cold shock proteins (CSPs) are a family of proteins induced at low temperatures. CSPs bind to single-stranded nucleic acids through the ribonucleoprotein 1 and 2 (RNP 1 and 2) binding motifs. CSPs play an essential role in cold adaptation by regulating transcription and translation via molecular chaperones. The solution nuclear magnetic resonance (NMR) or X-ray crystal structures of several CSPs from various microorganisms have been determined, but structural characteristics of psychrophilic CSPs have not been studied. Therefore, we optimized the purification process to obtain highly pure Lm-Csp and determined the three-dimensional structure model of Lm-Csp by comparative homology modeling using MODELLER on the basis of the solution NMR structure of Bs-CspB. Lm-Csp consists of a ${\beta}$-barrel structure, which includes antiparallel ${\beta}$ strands (G4-N10, F15-I18, V26-H29, A46-D50, and P58-Q64). The template protein, Bs-CspB, shares a similar ${\beta}$ sheet structure and an identical chain fold to Lm-Csp. However, the sheets in Lm-Csp were much shorter than those of Bs-CspB. The Lm-Csp side chains, E2 and R20 form a salt bridge, thus, stabilizing the Lm-Csp structure. To evaluate the contribution of this ionic interaction as well as that of the hydrophobic patch on protein stability, we investigated the secondary structures of wild type and mutant protein (W8, F15, and R20) of Lm-Csp using circular dichroism (CD) spectroscopy. The results showed that solvent-exposed aromatic side chains as well as residues participating in ionic interactions are very important for structural stability. Further studies on the three-dimensional structure and dynamics of Lm-Csp using NMR spectroscopy are required.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.250-253
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• 2007

Since Mg alloy has many attractive advantages among the practically used metals, many researchers have been studied to develop useful process and material. The crystal structure of Magnesium was hexagonal close-packed, so its formability was poor at room temperature. But formability was improved in high temperature with increasing of slip planes, twins, dynamic recrystallization. In this study The formability of AZ31B magnesium sheet is estimated according to the variable temperatures, forming speed, thickness, blank holding force. The results of deep drawing experiences show that the formability is well at the range from 200 to $250^{\circ}C$, 20 to 60 mm/min forming speed and 2.5 to 3KN blank holding force.

• Korean Journal of Crystallography
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• v.11 no.1
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• pp.22-27
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• 2000

The structure of cis-(malonato)[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) with a potent anticancer activity has been determined by the X-ray crystallographic method. Crystal data are as follows: Pt(C/sub 11/H/sub 20/N₂O/sub 6/), M/sub 4/=471.38, monoclinic, P2₁, a=7.112(1), b=33.615(3), c=7.135(1)Å, β=116.80(1)°, V=1522.6(3)Å, and Z=4. The two independent molecules with very similar structures are approximately related by pseudo two-fold screw axis symmetry, which makes the monolinic cell look like the orthorhombic cell with one molecule in the asymmetric unit and space group C222₁. The crystal packing mode is similar to that of the analogue with the dimethyl substituents instead of the isopropyl group. The Pt atom is coordinate to two O and two N atoms in a square planar structure. The six-membered chelate ring in the leaving ligand assumes a conformation intermediate between the half chair and the boat forms. The seven-membered ring in the carrier ligand assumes a twist-chair conformation and the oxolane ring assumes an envelope conformation. Crystal packing consists of the extensive hydrogen-bonding network in the two-dimensional molecular layers and weak van der Waals interactions between these layers.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1809-1814
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• 2006

The L-Valinate anion coordinating zinc complex, [$Zn(val)_2(H-2O)$], was isolated and structurally characterized by single crystal X-ray crystallography. The crystal possess orthorhombic symmetry with a space group $P2_12_12_1$, Z = 4, and a = 7.4279(2)$\AA$, b = 9.4342(2)$\AA$, c =20.5862(7)$\AA$ respectively. The compound features a penta-coordinate zinc ion in which the two valine anion molecules are directly coordinating the central zinc metal ion via their N (amine) and O (carboxylate) atoms, and an additional coordination to zinc is made by water molecule (solvent) to form a distorted square pyramidal structure. In addition, further synthesis of the valine capped ZnS:Mn nanocrystal from the reaction of [$Zn(val)_2(H-2O)$] precursor with $Na_2S$ and 1.95 weight % of $Mn^{2+}$ dopant is described. Obtained valine capped nanocrystal was water dispersible and was optically characterized by UV-vis and solution PL spectroscopy. The solution PL spectrum for the valine capped ZnS:Mn nanocrystal showed an excitation peak at 280 nm and a very narrow emission peak at 558 nm respectively. The measured and calculated PL efficiency of the nanocrystal in water was 15.8%. The obtained powders were characterized by XRD, HR-TEM, and EDXS analyses. The particle size of the nanocrystal was also measured via a TEM image. The measured average particle size was 3.3 nm.

• Journal of the Korean Chemical Society
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• v.39 no.5
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• pp.344-349
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• 1995

The crystal and molecular structure of the title compound has been determined from 2568 reflections collected on an automatic CAD4 diffractometer using graphite-monochromated $Mo-K\alpha$ radiation. The crystal is monoclinic system, space group $P2_1$ with unit cell dimensions $a=8.756(8)\AA$, $b=25.757(2)\AA$, $c=8.628(1)\AA$, $\beta=99.15(4)^{\circ}$, V= 1,921(2) ${\AA}^3$, Z=4, $D_C=1.336\;g/cm^3$, ${\mu}=1.54\;cm^{-1}\;and\;T=298^{\circ}K$. The final R factor was 0.051 for 2049 reflections over $3{\sigma}(Fο).$ The crystal has two asymmetric molecules in the unit cell. The arrangement of sulfon group was shown a distorted tetrahedron structure and N(6), N(6') atoms were deviated from the least-squares planes of the thiadiazine rings, respectively. The molecular packings in the unit cell are linked by the two intermolecular hydrogen bonds of N-H---O type and van der Waals forces.

• Journal of the Korean Chemical Society
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• v.38 no.11
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• pp.827-832
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• 1994

The crystal structure of bis(N-methylphenazinium) bis(oxalato)palladate(II) has been determined by X-ray crystallography. Crystal data: ((C_{13}H_{11}N_2)_2[Pd(C_2O_4)_2]) $M_w$ = 672.93, Triclinic, Space Group P1 (No = 2), a = 7.616(8), b = 9.842(3), c = $20.335(7)\AA$, $\alpha$ = 103.53(3), $\beta$ = 90.00(5), $\gamma$ = $112.38(5)^{\circ}$, Z = 2, $V = 1363(2){\AA}^3\;D_c = 1.639\;gcm^{-3},\;{\mu} = 7.3\;cm^{-1},\;F(000) = 680.0$. The intensity data were collected with $Mo-K\alpha$ radiation (${\lambda}$= 0.7107\;\AA)$ on an automatic four-circle diffractometer with a graphite monochromater. The structure was solved by Patterson method and refined by full matrix least-square methods using Killean & Lawrence weights. The final R and S values were $R = 0.069,\;R_w = 0.050,\;R_{all} = 0.069$ and S = 5.45 for 3120 observed reflections. Both cation and anion complexes are essentially planar and have dihedral angles of 6.3(6) and $57.06(6)^{\circ}$ between their planes. The planar complex anions are sandwiched between slightly bent cations. The interplanar separations of two triads are 3.328 and 3.463 $\AA$, respectively. The triads are stacked along b-axis, but their orientations are different based on dihedral angle $59.08(9)^{\circ}$ of two complex anions.

• Korean Journal of Crystallography
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• v.16 no.2
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• pp.138-140
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• 2005

A new crystal of helminth glutathione S-transferase, 28 kDa isozyme from Clonorchis sinensis has been grown from a 20% PEG MME 550 solution containing 50 mM $CaCl_{2}$ in 0.1 M bis-Tris buffer (pH 6.5) in $2{\sim}3$ days. The crystals diffract to $3.0{\AA}$ resolution and belong to the orthorhombic space group $P2_{1}2_{1}2_{1}$ with cell parameters $a=62.58{\AA},\;b=69.92{\AA},\;and\;c=339.67{\AA}$.

• Analytical Science and Technology
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• v.20 no.1
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• pp.61-69
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• 2007

The geometrical parameters, total and relative energies, vibrational frequencies, the HOMO-LUMO energy gap, and reorganization energies for the neutral molecule, anion, and cation of $C_{16}H_{16}O_3$ have been determined using density functional method (DFT). The highest level of theory employed in this study is $B3LYP/6-311G^{**}$. Harmonic vibrational frequencies were determined at the $B3LYP/6-311G^{**}$ level of theory. All positive vibrational frequencies were obtained to confirm minimum structures. The HOMO-LUMO energy gap and reorganization energies were calculated to predict the charge transport property of liquid-crystal.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.321-322
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• 2007

In this thesis, the sintering properties and piezoelectric properties of $Pb[(Co_{0.5}W_{0.5})_{0.03}(Ni_{1/3}Nb_{2/3})_{0.07}(Zr_{0.52}Ti_{0.48})_{0.9}]O_3+0.5[wt%]MnO_2$ ceramics has been systematically investigated as a function of the sintering temperature after manufacturing the specimens with a general method. The lattice constant from the analysis of crystal structure showed that the pychlore structure was decreased with the increase of the sintering temperature. Density was decreased by increasing $B_2O_3$. TCFr was showed its minimum variation rate of 0.35~-0.52[%] in the sintered temperature 950[$^{\circ}C$], $B_2O_3$ 3[wt%]. The electromechanical coupling coefficient (Kp) showed its maximum of 31.116[%] in the sintered temperature 1050[$^{\circ}C$], and its minimum of 20.220[%] in the sintered temperature 1150[$^{\circ}C$].

• Journal of the Korean Chemical Society
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• v.37 no.6
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• pp.599-603
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• 1993

Crystal structure of bis(1,2-diaminopropane)palladium(II) bis(oxalato)palladate(II) has been determined by X-ray crystallography. Crystal data: $Pd_2C_{10}H_{10}N_{4}O_{8}$, $M_W$ = 573.09, orthorhombic, space group $P_{ccn}$ (No = 56), a = 16.178(5), b = 16.381(6), c = 6.685(2)$\{AA}$, V = 1771.6 $\{AA}^3$, $M_W$W = 573.09, $D_c$ = 2.014 g${\cdot}c\;m^{-3}$, Z = 4, T = 294K, F(000) = 1056.0 and $\mu$ = 20.466 c$m^{-1}$. The intensity data were collected with $Mo-K\alpha$ radiation (${\lambda}$ = 0.7107 $\AA)$ on an automatic four-circle diffractometer with a graphite monochromater. The structure was solved by Patterson method and refined by full matrix least-squares methods using Pivot weights. The final R and S values were R = 0.065, $R_W = 0.059, R_{all}$ = 0.065 and S = 4.315 for 605 observed reflections. Both cation and anion complexes are essentially planar and have dihedral angle of $18(l)^{\circ}$ between thier planes. In the crystal structure, they do not have the Magnus's salt type mixed stacks; instead, the complex anions form regular stacks along the c-axis with the M-M bond length of $3.343(5)\AA$ and their stacks are surrounded by the complex cations through hydrogen bonds with the nitrogen-oxygen distances of 2.94(3) and $3.31(4)\AA.$