• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.78-82
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• 2021

The Ga₂O₃ single crystal was grown through a floating zone method, and its structural and optical properties were instigated. It has a monoclinic crystal structure with a (100) crystal orientation and an optical band gap energy of 4.6 eV. It showed an average transmittance of 70% in the visible region. At room temperature, its photoluminescent spectrum showed three different peaks: the ultraviolet at 360 nm, the blue-green at 500 nm, and the red peaks at 700 nm. Especially, at liquid nitrogen temperature, the ultraviolet peak was optically active while the others were quenched.

• Proceedings of the Korea Crystallographic Association Conference
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• 2000.11a
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• pp.10-10
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• 2000

• Bulletin of the Korean Chemical Society
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• v.14 no.2
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• pp.200-206
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• 1993

Structures of two polymorphs of ${\alpha},{\alpha}$-trehalose octaacetate monohydrate, $C_{28}H_{38}O_{19}\;{\cdot}\;H_2O$, have been studied by X-ray diffraction method. ${\alpha},{\alpha}$-trehalose (${\alpha}$-D-glucopyranosyl ${\alpha}$-D-glucopyranoside) is a nonreducing disaccharide. The polymorph I belongs to the monoclinic $P2_1$, and has unit cell parameters of a=10.725(l), b=15.110(4), c=11.199(5) ${\AA}$, ${\beta}=108.16(2)^{\circ}$ and Z=2. The polymorph II is orthorhombic $P2_12_12_1$, with a=13.684(4), b=15.802(4), c=17.990(9) ${\AA}$ and Z=4. The final R and R$_w$ values for monoclinic polymorph I are 0.043 and 0.048 and for orthorhombic polymorph II are 0.116 and 0.118, respectively. Those R values of polymorph II are high because the large thermal motions of acetyl groups and the poor quality of the crystal. The molecular conformations in the two polymorphs are similar. Both D-glucopyranosyl rings have chair $^4C_1$ conformations and atoms of glycosidic chain ${\alpha}(1{\rightarrow}1)$ linkage are coplanar. The primary acetate groups of the pyranose residues assume both gauche-trans conformations. The molecules of two polymorphs have pseudo-C$_2$ symmetry at glycosidic O(1) atom. The bond lengths and angles are normal compared with those in other acetylated sugar compounds. The molecules in the monoclinic crystal are held by the hydrogen bonds with the water molecules and by van der Waals forces.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.117-125
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• 1997

Ferroelastic $CsPbCl_3$ crystals were grown by the Czochralski method and Bridgman method. From XRD, DTA and the dielectric measurements, we investigated the structure and confirmed the phase transition temperatures of it. Using the polarizing microscope, we observed the ferroelastic domains and the temperature dependence of the domains. For the orientation states, we obtained the consistent result with the theoretical investigation by the crystallographical consideration. For Aizu species m3mF2/m(p) 12 orientation states are represented crystallographically.

• Archives of Pharmacal Research
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• v.14 no.1
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• pp.1-6
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• 1991

The crystal structure of licarin-B, a component of Myristicae Semen was determined by single crystal X-ray diffraction analysis. Crystal of the compound, which was recrystallized from the mixture of hexane and ether, is monoclinic with a=12.740(1), b=7.219(1), c=9.284(1) ${\AA}$, ${\beta}=94.75(1)^{\circ}$, $D_x=1.26$, $D_m=1.27\;g/cm^3$, space group P21, and Z=2. The structure was solved by direct method and refined by least-squares procedure to the final R value of 0.040 for 1532 independent reflections ${F{\ge}3{\sigma}(F)}$. The compound is a dimeric phenylpropanoid, and belongs to the neolignan analogues. The molecules are arranged along with the screw axis. The intermolecular contacts appear to be the normal van der Waals' forces.

• Archives of Pharmacal Research
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• v.25 no.1
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• pp.25-27
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• 2002

The crystal structure of KR-21042, N-(3-Phenylpropyl )-4-hydroxy-3-methoxyphenylacetamide, was determined by single crystal X-ray diffraction analysis. The compound was recrystallized from a mixture of ethylacetate and n-hexane in monoclinic, space group $P2_1/c$, with a = 16.622(1), b = 6.215(1), c = 15.802(1) ${\AA},{\;}{\beta}=104.97(1)$, and Z = 4 The calculated density is $1.261{\;}g/cm^3$The structure was solved by the direct method and refined by full matrix least-squares procedure to the fecal R value of 0.068 for 2332 observed reflections.

• Bulletin of the Korean Chemical Society
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• v.5 no.1
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• pp.23-26
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• 1984

The crystal structure of phthalylsulfacetamide, one of the long-acting 'sulfa' drugs, has been determined by the X-ray diffraction methods. The crystal is monoclinic with cell dimensions of a = 7.980(3), b = 12.784(2), c = 18.064(7) ${\AA}$ and ${\beta}$= $112.94(2)^{\circ}$, space group $P2_1$/c and Z = 4. The structure was solved by the direct methods and refined to R = 0.048. The sulfonylacetamide moiety is folded with respect to the central phenyl ring and the benzamide and benzoyl planes are nearly perpendicular to each other. This conformation is consistent with those of the relevant molecules containing the corresponding moieties. All of the molecules in the crystal lattice are connected by a three-dimensional hydrogen bonding network.

• Journal of Ocean Engineering and Technology
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• v.11 no.1
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• pp.49-54
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• 1997

On the precipitatiopn and ripening reaction of the precipitates from a lead nitrate and an oxalic acid dissolved in ethanol, a new crystalline phase was obtained, whose X-ray diffraction data have not previously been reported. The crystal system was determined to be monoclinic. The unit-cell parameters were refined to a =10.613(2)$\AA$, b =7.947(2))$\AA$, c =6.189(1)$\AA$, and $\beta$=104.48(2)$^{\circ}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.71-71
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• 2010

Copper oxide thin films were deposited on the p-type Si(100) by r.f. magnetron sputtering as a function of different substrate temperature. The deposited copper oxide thin films were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), spectroscopic ellipsometry (SE), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The SEM and SE data show that the thickness of the copper oxide films was about 170 nm. AFM images show that the surface roughness of copper oxide films was increased with increasing substrate temperature. As the substrate temperature increased, monoclinic CuO (111) peak appeared and the crystal size decreased while the monoclinic CuO (-111) peak was independent on the substrate temperature. The oxidation states of Cu 2p and O 1s resulted from XPS were not affected on the substrate temperature. The contact angle measurement was also studied and indicated that the surface of copper oxide thin films deposited high temperature has more hydrophobic surface than that of deposited at low temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.272-279
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• 2003

In this work Zn$_4$GeSe$_{6}$ :CO$^{2+}$ single crystals were grown by the chemical transport reaction method in which the iodine was used as the transporting agent. The Zn$_4$GeSe$_{6}$ :CO$^{2+}$ single crystal was found to have a monoclinic structure. The optical absorption spectra of grown crystals were investigated using a temperature-controlled UV-VIS -NIR spectrophotometer. The temperature dependence of band-edge absorption was in a good agreement with the Varshni equation. The observed impurity absorption peaks could be explained as arising from the electron transition between energy levels of Co$^{2+}$ ion sited at the T$_{d}$ symmetry point.