• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.394-399
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• 1999

As the prosthetic application of natural mineral substituted for chemical reagent, composites and a glass-ceramics containing hydro-xyapatite isolated from tuna bone were prepared by solid state reaction. On x-ray examinations, the major phases of composites were identified as pseudowollastonite(${\alpha}-CaSiO_3$) and ${\beta}$-tricalcium phosphate($\beta$-TCP) and the phase of a glass-ceramics was observed as $\beta$-TCP and fluoroapatite caused by $CaF_2$ respectively. SEM images depict that the microstructures of grain at the composites were a function of temperature. The measured strength of a glass-ceramics prepared at $900^{\circ}C$ for 4 hr in air was 90 MPa as a 4-point bending method and this value was similar to the cortical bone, as 50~150 MPa but it was lower than its maximum strength.

• Archives of Pharmacal Research
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• v.25 no.3
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• pp.275-279
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• 2002

The crystal structure of byakangelicin, one of furanocoumarin aldose reductase inhibitors, was determined by X-ray diffraction method. The crystal is triclinic, with a=8.114(1), b=10.194(1), $c=11.428(1)\AA,{\;}{\alpha}=111.50(1),{\}{\beta}=95.57(1),{\}{\gamma}=112.52(1)^{circ},{\;}D_x=1.41,{\;}D_m=1.39{\;}g/cm^3$, space group P1 and Z=2. The intensity data were collected by ${\omega}-2{\theta}$ scan method with $CuK_{a}$ radiations. The structure was solved by direct method and refined by full matrix least-squares procedure to the final R-value of 0.056. There are two molecules with different conformations in an asymmetric unit. The molecules are kept by two intermolecular O-HO type hydrogen bonds and van der Waal's forces in the crystal. The absolute configuration of the molecules was estimated to S-form by the 'Eta refinement' procedure.

• Korean Journal of Crystallography
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• v.14 no.1
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• pp.16-23
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• 2003

The electronic structure and chemical bonding of β-MnO₂ were theoretically investigated by DV-X/sub α/ (the discrete variation X/sub α/) method. which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The calculations on several cluster models having different sizes were carried out for the determination of a model suited for analyzing bulk state. The Mn/sub 15/O/sub 56/ model was selected as a sufficiently suitable model for the calculation of electronic state and chemical bonding by the comparison of the calculated XPS (X-ray photo-electron spectrum) and experimentally measured XPS. By using this model, the electron energy level, the density of state, the bond overlap population, the charge density distribution, and the net ionic transfer between cations and anions were calculated and discussed.

• Journal of Integrative Natural Science
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• v.9 no.2
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• pp.94-102
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• 2016

The crystal structure of the potential active 6-ethoxy-3-phenyl-5a,9a-dihydro-3H-chromen[4,3-c][1,2]oxazole-3a(4H)-carbonitrile ($C_{19}H_{15}N_2O_3$) has been determined from single crystal X-ray diffraction technique. The title compound crystallizes in the monoclinic space group C2/c with unit cell dimension a= 29.3026(9) ${\AA}$, b= 6.7695(2) ${\AA}$ and c= 19.7597(6) ${\AA}$ [${\alpha}= 90^{\circ}$, ${\beta}= 125.709(10)^{\circ}$ and ${\gamma}= 90^{\circ}$]. Single crystals suitable for X-ray diffraction were obtained by slow evaporation method, the isoxazole and six membered pyran rings adopts envelope conformation. The crystal packing of the molecules is stabilized by the weak $C-H{\ldots}N$ hydrogen bond interaction.

• Journal of Integrative Natural Science
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• v.9 no.2
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• pp.103-112
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• 2016

The crystal structure of the potential active Methyl 8-bromo-3-phenyl-5a,9a-dihydro-3H-chromen [4,3-c][1,2] isoxazole-3a(4H)-carboxylate ($C_{18}H_{15}BrNO_4$) has been determined from single crystal X-ray diffraction technique. The title compound crystallizes in the triclinic space group Pī with unit cell dimension a=8.3129 (3) ${\AA}$, b=9.5847 (4) ${\AA}$ and c=11.1463(4) ${\AA}$ [${\alpha}=98.457(3)^{\circ}$, ${\beta}=102.806(2)^{\circ}$ and ${\gamma}=105.033(5)^{\circ}$]. Single crystals suitable for X-ray diffraction were obtained by slow evaporation method, the isoxazole and six membered pyran rings adopts envelope conformation. In the crystal, molecules are linked via pairs of inter molecular $C-H{\ldots}O$ hydrogen bonds to form dimmers.

• Molecules and Cells
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• v.20 no.3
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• pp.361-363
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• 2005

Plasmid Achromobacter secretion (PAS) factor is a putative secretion factor that induces the secretion of periplasmic proteins. PAS factor from Vibrio vulnificus was crystallized at 294 K by the hanging drop vapor-diffusion method. It was isolated as a monomer during the purification procedures. The native crystal belongs to the F222 space group with unit cell parameters a = 56.1, b = 74.4, $c=80.0{\AA}$, ${\alpha}={\beta}={\gamma}=90^{\circ}$. The crystal was soaked in cryoprotectant containing 1 M NaBr for 1 h for MAD phasing. The diffraction limit of the Br-MAD data set was $1.9{\AA}$ using synchrotron X-ray irradiation at beam line BL-18B at the Photon Factory, Japan.

• Progress in Medical Physics
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• v.2 no.2
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• pp.149-154
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• 1991

We have designed and applied the calibrationmethod of $\^$90/Sr Ophthalmic Applicaton by measuring the electron currents. We considered the number of electrons which is emitted from the source, the area of the source, and the electron stopping power in the water, and those data were used for calculation. Film was used for evaluating the accurate source area. Average electron stopping power was obtained by analyzing ${\beta}$-ray energy spectrum. We compared between the result from our method and that from the TLD measurements. The calibration result from our method shows 63.3 ${\pm}$5.1 cGy/sec, while 50.7${\pm}$7.3 cGy/sec from TLD measurement. But the supplier's specification tells 46.89.4cGy/sec.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1108-1112
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• 1994

25-Acetoxy-26,27,28-trimethoxycalix[4]arene was synthesized by the treatment of calix[4]arene trimethyl ether with acetyl chloride in the presence of NaH. The solution conformation was inferred as a partial cone conformation based on the $^1H$-and $^{13}C$ NMR spectra. The crystal structure has been determined by X-ray diffraction method. The crystals are monoclinic, space group $P2_1$/n, a=8.186 (1), b=17.137 (2), c=19.878 (3) ${\AA}$, ${\beta}$=95.67 (1)$^{\circ}$, Z=4, V=2774.90 ${\AA}^3$, $D_c$= 1.22 g $cm^{-3}$, $D_m$=1.23 g $cm^{-3}$. The intensity data were collected on an Enraf-Noninus CAD-4 Diffractometer with a graphite monochromated $Cu-K{\alpha}$ radiation. The structure was solved by direct method and refined by full-matrix least-squares methods to a final R value of 0.054 for 3675 observed reflections. The molecule possesses a partial cone conformation with one flattened phenyl unit, in which one anisol ring, distal to the ester ring, is inverted. The acetoxyphenyl ring is flattened.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.209-214
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• 2007

In Korean geology that crystalline rock is dominant, the properties of subsurface including the anisotropy are distributed complexly and changed abruptly. Because of such geological environments, cross-hole seismic traveltime tomography is widely used to obtain the high resolution image of the subsurface for the engineering purposes in the geotechnical sites. However, because the cross-hole tomography has a wide propagation angle coverage relatively, its data tend to include the seismic velocity anisotropy comparing with the surface seismic methods. It can cause the misinterpretation that the cross-hole seismic data including the anisotropic effects are analyzed and treated with the general processing techniques assuming the isotropy. Therefore, we need to consider the seismic anisotropy in cross-hole seismic traveltime tomography. The seismic anisotropic tomography algorithm, which is developed for evaluation of the velocity anisotropy, includes several inversion schemes in order to make the inversion process stable and robust. First of all, the set of the inversion parameters is limited to one slowness, two ratios of slowness and one direction of the anisotropy symmetric axis. The ranges of the inversion parameters are localized by the pseudo-beta transform to obtain the reasonable inversion results and the inversion constraints are controlled efficiently by ACB(Active Constraint Balancing) method. Especially, the inversion using the Fresnel volume is applied to the anisotropic tomography and it can make the anisotropic tomography more stable than ray tomography as it widens the propagation angle coverage.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.189-195
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• 2009

$\beta-Ga_{2}O_{3}$ nanorods were synthesized by chemical vapor deposition method using nickel-oxide nanoparticle as a catalyst and gallium metal powder as a source material. The average diameter of nanorods was around 160 nm and the average length was $4{\mu}m$. Also, we confirmed that the synthesis of nanorods follows the vapor-solid growth mechanism. From the results of X-ray diffraction and HR-TEM observation, it can be found that the synthesized nanorods consisted of a typical core-shell structure with single-crystalline $\beta-Ga_{2}O_{3}$ core with a monoclinic crystal structure and an outer amorphous gallium oxide layer. Li/$\beta-Ga_{2}O_{3}$ nanorods cell delivered capacity of 867 mAh/g-$\beta-Ga_{2}O_{3}$ at first discharge. Although the Li/$\beta-Ga_{2}O_{3}$ nanorods cell showed low coulombic efficiency at first cycle, the cell exhibited stable cycle life property after fifth cycle.