• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3093-3097
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• 2013

The synthesis, X-ray crystallography, spectroscopic (IR, UV-vis), and electrochemical properties of the title compound, $[H_3O][Cr(dipic)_2][H_3O^+.Cl^-]$ (1), ($H_2dipic$ = 2,6-pyridinedicarboxylic acid), are reported. This complex crystallizes in the monoclinic space group Cc with a = 14.9006(10) ${\AA}$, b = 12.2114(8) ${\AA}$, c = 8.6337(6) ${\AA}$, ${\alpha}=90.00^{\circ}$, ${\beta}=92.7460(10)^{\circ}$, ${\gamma}=90.00^{\circ}$, and V = 1569.16(18) ${\AA}^3$ with Z = 4. The hydrogen bonding and noncovalent interactions play roles in the stabilization of the structure. In order to gain a better understanding of the most important geometrical parameters in the structure of the complex, atoms in molecules (AIM) method at B3LYP/6-31G level of theory has been employed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.353-354
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• 2009

Tensile deformation behavior with different strain rate was investigated. $Zr_{56.2}Ti_{13.8}Nb_{5.0}Cu_{6.9}Ni_{5.6}Be_{12.5}$ (bulk metallic glass alloy possessed crystal phase which was called $\beta$-phase of dendrite shape, mean size of $20{\sim}30{\mu}m$ and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74Gpa at strain rate of $10^2/s$ and minimum strength was found to be 1.6GPa at $10^{-1}/s$. And then, maximum plastic deformation occurred at the strain rate of $5{\times}10^{-2}/s$ and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.70-70
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• 2003

Active sites and substrate bindings of 1-aminoxyclopropane-1-carboxylate oxidase (MD-ACO1) catalyzing the oxidative conversion of ACC to ethylene have been determined based on site-directed mutagenesis and comparative modeling methods. Molecular modeling based on the crystal structure of Isopenicillin N synthase (IPNS) provided MD-ACO1 structure. MD-ACO1 protein folds into a compact jelly roll shape, consisting of 9 ${\alpha}$-helices, 10 ${\beta}$-strands and several long loops. The MD-ACO1/ACC/Fe(II)/Ascorbate complex conformation was determined from automated docking program, AUTODOCK. The MD-ACO1/Fell complex model was consistent with well known binding motif information (HIS177-ASP179-HIS234). The cosubstrate, ascorbate is placed between iron binding pocket and Arg244 of MD-ACO1 enzyme, supporting the critical role of Arg244 for generating reaction product. These findings are strongly supported by previous biochemical data as well as site-directed mutagenesis data. The structure of enzyme/substrate suggests the structural mechanism for the biochemical role as well as substrate specificity of MD-ACO1 enzyme.

• 한국전기전자재료학회논문지
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• 제26권8호
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• pp.620-623
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• 2013

The carbon nanotube / poly-vinylidene fluoride (CNT/PVDF) composite films for the nano-generator devices were fabricated by spray coating method using the CNT/PVDF solution, which was prepared by adding PVDF pellets into the CNT dispersed N-Methyl-2-pyrroli-done (NMP) solution. The flexible CNT/PVDF composite films were investigated by the scanning electron microscopy, which revealed that the CNTs were uniformly dispersed in the PVDF matrix and thickness of the films was approximately $20{\mu}m$. Fourier transform infra-red spectra were used to investigate crystal structure of the as-spray-coated CNT/PVDF films, and we found that they revealed extremely large portion of the ${\beta}$ phase PVDF. The capacitance of the CNT/PVDF films increased by adding CNTs into the PVDF matrix, and finally saturated. However, the resistance didn't show any saturation effect in the CNT concentration range of 0~4 wt%. Finally, the resulting nano-generator devices revealed reasonable current output after given mechanical stress.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2006년도 International Meeting of the Microbiological Society of Korea
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• pp.66-68
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• 2006

SUF machinery in Echerichia coli, responsible for the biosynthesis of iron-sulfur clusters, is composed of six protein components (SufABCDSE), among which SufB, SufC, and SufD associate in a complex. We have determined the structures of SufA, SufC, and SufD by X-ray crystallography. SufA is a dimer, in which C-terminal segments containing essential cysteine residues (Cys-Gly-Cys) are positioned to allow coordination of an Fe-S cluster and/or an Fe atom. SufC has the overall structure similar to that of ABC-ATPase but takes an inactive form. SufD has a ${\beta}-helix$ flanked with a-helical domains. We also studied the functional roles of the residues in SufD by mutagenesis and determined the crystal structure of SufCD complex. Molecular mechanism of Fe-S cluster biosynthesis is discussed on the basis of the structural and functional evidence.

• 한국세라믹학회지
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• 제26권3호
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• pp.315-322
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• 1989

Li2O-Al2O3-SiO2 system glasses contained P2O5, TiO2 and ZrO2as the nucleating agents were melted and formed. The glass was subsequently heated first to nucleate and then to grow the crystals. At constant nucleating agent content the base glass compositions were varied and the influences of these variations on the crystallization behaviour were investigated. The study was made by measurement of thermal expansion coefficient, differential thermal analysis, X-ray diffraction analysis, scanning electron microscope observation and transmission measurement of crystallized glass specimen in visible region. It was shown that the content of crystalline phase decreased with increasing SiO2 content as well as decresing Li2O in the base glass compositions. As the result of X-ray diffrection analysis, the major crystal was $\beta$-quartz solid solution. The degree of crystallinity which was calculated using the noncrystalline scattering methods increased in S-shape with increasing heat treatment time. This change was similar to that in thermal expansion coefficient. The transmissions of 5mm thick samples were 80-90% in visible ray region.

• 한국전기전자재료학회논문지
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• 제17권6호
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• pp.641-646
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• 2004

We report the changes of the microwave reflection coefficients S$_{11}$ of copper(II)-phthalocyanine (CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand the phase transition of CuPc. For a NSMM system, a high-quality microstrip resonator coupled with a dielectric resonator was used. CuPc thin films were prepared on the pre-heated glass substrates using a thermal evaporation method. The reflection coefficients S$_{11}$ of CuPc thin films were changed by the dependence on the substrate pre-heating temperatures. By comparing reflection coefficient S$_{11}$ and crystal structures, we found the phase transition of CuPc thin films from $\alpha$-phase to $\beta$-phase at the substrate heating temperature 200 $^{\circ}C$./TEX>.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.191-193
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• 2004

The composites were fabricated, respectively, using 61vol.% SiC-39vol.% $TiB_2$ and using 61vol.% SiC-39vol.% $ZrB_2$ powders with the liquid forming additives of 12wt% $Al_2O_3+Y_2O_3$ by hot pressing annealing at $1650^{\circ}C$ for 4 hours. Reactions between SiC and transition metal $TiB_2$, $ZrB_2$ were not observed in this microstructure. The result of phase analysis of composites by XRD revealed SiC(6H, 3C), $TiB_2$, $ZrB_2$ and $YAG(Al_5Y_3O_{12})$ crystal phase on the SiC-$TiB_2$, and SiC-$ZrB_2$ composites. The ${\beta}\;{\alpha}$-SiC phase transformation was occurred on the $SiC-TiB_2$, $SiC-ZrB_2$ composites. The relative density, the flexural strength and Young's modulus showed respectively value of 98.57%, 226.06Mpa and $86.37{\times}10^3Mpa$ in SiC-$ZrB_2$ composites.

• Journal of Pharmaceutical Investigation
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• 제18권4호
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• pp.209-215
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• 1988

The three-dimensional structures of piroxicam crystallized from two different solvents, toluene and toluene/hexane mixture respectively, are proved identical: $C_{15}H_{13}N_3O_4S,\;M\;=\;331.35$, monoclinic, a = 7.128(1), b = 15.146(2), c = 13.956(2) ${\AA},\;{\beta}=\;97.33(1)^{\circ},\;V\;=\;1494.37{\AA}^{3},\;Dx\;=\;1.472\;g/cm^{3},\;Z\;=\;4,\;space\;group\;P2_{1}/c,\;Mo\;K{\alpha}(\lambda=\;0.71073\;{\AA})$, F(000) = 688, T = 295 K, R = 0.0611 for 1993 unique observed reflections. The thiazine ring exhibits a half chair conformation. An amide group is involved in an intramolecular hydrogen bond to the hydroxy group, O(17)-H(17)${\cdots}O(15){\AA}$. The molecule is planar within 2 ${\AA}$ with the interplanar angle $127.9(4)^{\circ}$ between pyridine and benzene rings. A molecular chain parallel to [011] is formed by two intermolecular hydrogen bonds N(16)-H(6)${\cdots}O(11)$ and C(6)-H(6)${\cdots}O(11)$, and the molecular chains are held together by van der Waals forces.

• Applied Microscopy
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• 제36권spc1호
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• pp.57-61
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• 2006

High-resolution microscopy was applied for surveying hydride stability in Vanadium alloys, which are candidate for hydrogen storage materials of advanced hydrogen energy systems. $V_2H$ hydride in V alloys was stable at room temperature under the vacuum condition, but it was decomposed during heating up to $100^{\circ}C$. It was confirmed from HRTEM image and FFT that $V_2H$ has a BCT structure, where hydrogen atoms locate at octahedral sites. Crystal orientation was <110> beta// <110> mat., and lattice strain is about 10%. After the decomposition of the hydride, relatively large lattice expansion was observed in the matrix, which suggests that hydrogen atoms should be trapped by lattice defects and included in the matrix. Intensive electron beam also enhanced the decomposition.