• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.92-96
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• 2009

A new precursor [$Zr(acac)_{3}(H_{2}O)_{2}$] was synthesized by Sonochemical technique and used to deposit thin $ZrO_{2}$ film on quartz and ceramic substrate via ultrasonic aerosol assisted chemical vapour deposition (UAACVD) at 300 ${^{\circ}C}$ in oxygen environment followed by annealing of the sample for 2-3 minutes at 500 ${^{\circ}C}$ in nitrogen ambient. The molecular structure of the precursor determined by single crystal X-ray analysis revealed that the molecules are linked through intermolecular hydrogen bonds forming pseudo six and eight membered rings. DSC and TGA/FTIR techniques were used to determine thermal behavior and decomposition temperature of the precursor and nature of evolved gas products. The optical measurement of annealed $ZrO_{2}$ film with tetragonal phase shows optical energy band gap of 5.01 eV. The particle size, morphology, surface structure and composition of deposited films were investigated by XRD, SEM and EDX.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.1
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• pp.49-52
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• 2016

The effect of process parameters such as the growth pressure and temperature on the AlN crystal growth has been investigated. AlN crystal was grown onto 6H-SiC seed crystal using PVT (Physical Vapor Transport) method. Crystal properties and morphology of AlN crystal was changed with growth pressure and temperature. Raman analysis confirmed that AlN crystals with different orientation were successfully grown on SiC seed crystal.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.2
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• pp.87-90
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• 2002

$LiCoO_{2}$ powders were synthesized at various temperatures using lithium hydroxide and cobalt hydroxide as precursors prepared by precipitation process and freeze-drying. In this study, the$LiCoO_{2}$ samples were synthesized via a solid state reaction with various LiOH concentration between 10 % and 30 % excess. And $LiCoO_{2}$powders were calcined at 600~$800^{\circ}C$ in a short time. Measurements of XRD and SEM were performed to characterize the properties of the prepared materials. The effect of amount of Li ions on the structural change in powder has been examined using the XRD analysis. For the not added excess of LiOH, CoOOH phase presented in the XRD pattern of $LiCoO_{2}$ due to loss of Li ions during firing. The morphology and particle size of the powders were examined using SEM. The obtained powders are high temperature-$LiCoO_{2}$HT-LiCoO$_{2}$) and homogeneous with the range of grain size in the order of hundreds of nanometers. The effects of variation of LiOH concentration on the structural change in powder were investigated using the Rietveld analysis. As an analysis result, c/a is constant by 4.99 on all occasions. Finally, the structure of HT-$LiCoO_{2}$ was simulated by the commercial software $Creius^{2}$(Molecular Simulations, Inc.) from the results of Rietveld analysis.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.374-378
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• 2013

Two novel binuclear metal-organic coordination complexes [$Cd_2(Hdpa)_4(bpy)_2$] (1), [$Dy_2(dpa)_2(bpy)_2(NO_3)_2-(H_2O)_2$](bpy) (2) (where $H_2dpa$ = biphenyl-2,2'-dicarboxylic acid, bpy = 2,2'-bipyridine) have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, spectral method (IR), elemental analysis (EA), powder X-ray diffraction (XRD), electronic spectra (UV-vis), fluorescent in the solid state and thermogravimetric analysis (TGA). Complexes 1-2 crystallizes isomorphously in the Triclinic space group P-1. The ${\pi}-{\pi}$ stacking interactions and hydrogen-bonds play a vital role in determining the crystal packing and construction of the extended 3-D supramolecular network.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.5-12
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• 2006

This study was conducted to investigate the effect of operational parameters such as dosage of magnesium and phosphate, pH, reaction time and existence crystal core for the removal of nitrogen and phosphorus in anaerobic fermentation supernatant by struvite crystallization. Optimal mole ratio of $Mg^{2+}:NH_4{^+}:PO_4{^{3-}}$ was 1.2:1.0:1.2. Under the optimal molar ratio, removal ratio and reaction rate constant of $NH_4{^+}-N$ and $PO_4{^{3-}}-P$ were 79.2, 96.8%, 0.157 and $0.344min^{-1}$, respectively. Optimal pH and reaction time were 11 and 10 minutes, respectively, in the optimal molar ratio. Residual concentration of $NH_4{^+}-N$ and $PO_4{^{3-}}-P$ showed lowest value with 1 g/L of crystal core addition. SEM analysis of struvite crystallization with crystal core showed higher crystal core growth than that of without crystal core. Struvite precipitate proved to be orthorhomic crystal structure by XRD analysis.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2086-2092
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• 2013

Two new high-nitrogen energetic compounds $ZTO{\cdot}2H_2O$ and $ZTO(phen){\cdot}H_2O$ have been synthesized (where ZTO = 4,4-azo-1,2,4-triazol-5-one and phen = 1,10-phenanthroline). The crystal structure, elemental analysis and IR spectroscopy are presented. Compound 1 $ZTO{\cdot}2H_2O$ crystallizes in the orthorhombic crystal system with space group Pnna and compound 2 $ZTO(phen){\cdot}H_2O$ in the triclinic crystal system with space group P-1. In $ZTO(phen){\cdot}H_2O$, there is intermolecular hydrogen bonds between the -NH group of ZTO molecule (as donor) and N atom of phen molecule (as acceptor). Thermal decomposition process is studied by applying the differential scanning calorimetry (DSC) and thermo thermogravimetric differential analysis (TG-DTG). The DSC curve shows that there is one exothermic peak in $ZTO{\cdot}2H_2O$ and $ZTO(phen){\cdot}H_2O$, respectively. The critical temperature of thermal explosion ($T_b$) for $ZTO{\cdot}2H_2O$ and $ZTO(phen){\cdot}H_2O$ is $282.21^{\circ}C$ and $195.94^{\circ}C$, respectively.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1697-1702
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• 2014

A novel complex [$Zn(phen)(o-AB)_2$] [phen: 1,10-phenanthroline o-AB: o-aminobenzoic acid] was synthesized and characterized by elemental analysis and X-ray diffraction single-crystal analysis. The crystal crystallizes in monoclinic, space group P2(1)/c with $a=7.6397(6){\AA}$, $b=16.8761(18){\AA}$, $c=17.7713(19){\AA}$, ${\alpha}=90^{\circ}$, ${\beta}=98.9570(10)^{\circ}$, ${\gamma}=90^{\circ}$, $V=2.2633(4)nm^3$, Z = 4, F(000) = 1064, S = 1.058, $Dc=1.520g{\cdot}cm^{-3}$, $R_1=0.0412$, $wR_2=0.0948$, ${\mu}=1.128mm^{-1}$. The Zn(II) is six coordinated by two nitrogen and four oxygen atoms from the 1,10-phenanthroline and o-aminobenzoic acid to furnish a distorted octahedron geometry. The complex exhibits intense fluorescence at room temperature. Theoretical studies of the title complex were carried out by density functional theory (DFT) B3LYP method. CCDC: 898291.

• Analytical Science and Technology
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• v.18 no.4
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• pp.278-286
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• 2005

The crystal structure of ($Tl_{71}$-Y ($Tl_{71}Si_{121}Al_{71}O_{384}$), ${\alpha}=24.706(3){\AA}$, dehydrated at 653 K and $8{\times}10^{-6}$ torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group $Fd\bar{3}m$ at 294(1) K. The structure was refined using all intensities to the final error indices (using only the 302 reflection for which $F_{\circ}$ > $4{\sigma}(F_0)$) $R_1=0.0602$ (based on F) and $R_w=0.1744$ (based on $F_2$). The 71 $Tl^+$ ions per unit cell are found at four crystallographically distinct positions. Site I' position in the sodalite cavity opposite D6Rs are each occupied by eighteen $Tl^+$ ions per unit cell; these $Tl^+$ ions are recessed ca. $1.45{\AA}$ into the sodalite cavity from their O(3) plane (Tl-O=2.701(15), $3.163(16){\AA}$ and O-Tl-O=$92.1(4)^{\circ}$). The 23 $T1^+$ ions fill site II in the supercage; these $T1^+$ ions are recessed ca. $1.58{\AA}$ into the supercage from their O(2) plane (Tl-O = 2.850(16), $3.156(16){\AA}$ and O-T1-O = $85.1(5)^{\circ}$). The 19 $Tl^+$ ions lie at site III' in the supercage near a triple 4-ring (Tl-O = 3.10(7), $3.39(5){\AA}$ and O-Tl-O = 47.8(9), $95.3(18)^{\circ}$) and the remaining II ions occupy another site III' near a triple 4-ring in the supercage (Tl-O = 2.81(4), $2.71(4){\AA}$ and O-Tl-O = $57.3(8)^{\circ}$).

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.687-693
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• 2006

Chromium(III) complexes, cis-[Cr([14]-decane)$(HOC _6H _4COO) _2$]$ClO _4$ I and cis-[Cr([14]-decane)(OH) $(OC _6H _4NO _2)$]$ClO _4{\cdot}H _2O$ II ([14]-decane = rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-teraazacyclotetradecane) are synthesized and structurally characterized by a combination of elemental analysis, conductivity, IR and VIS spectroscopy, and X-ray crystallography. The complexes crystallizes in the monoclinic space groups, $C2 _1$/a in I and $P2 _1$/n in II. Analysis of the crystal structure of complex I reveals that central chromium(III) ion has a distorted octahedral coordination environment and two hydrogensalicylato ligands are unidentate to the chromium(III) ion via the carboxyl groups in the cis-position. For monomeric complex I the hydrogensalicylato coordination geometry is as follows: Cr-O(average) = 1.984(3) $\AA$;Cr-N range = 2.105(3)-2.141(4) $\AA$;C(24)-O(4) = 1.286(5) $\AA$;N(2)-Cr-N(4) (equatorial position) = 96.97(15)${^{\circ}}$; N(1)-Cr-N(3) (axial position) = 168.27(15)${^{\circ}}$; O(1)-Cr-O(4) = 85.70(13)${^{\circ}}$. The crystal structure of II has indicated that chromium(III) ion is six-coordinated by four secondary amines of the macrocycle, hydroxide anion and nitrophenolate anion.

• Korean Journal of Heritage: History & Science
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• v.45 no.4
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• pp.114-125
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• 2012

The purpose of this study is to analysis chromaticity, granulometry, main chemical composition and mineral crystal structure of wall soils excavated from Poongnatoseong Earthen Castle using color reader, XRD, particla size analyzer. The analysed soils of Poongnatoseong Earthen Castle were yellowish brown and isabella. All samples were sands or sands including silty soil(SW~SC) and showed similar granulometry, chemical composition and mineral crystal structure, which were characteristics of construction materials suitable for modern road or airstrip. As resulting in comparison with 4 factors from chromaticity, granulometry, main chemical composition and mineral crystal structure, we decided that the control soils(PNS) near by Poongnatoseong Earthen Castle were not to be used for the castle wall construction We presumed that there was a huge soil distribution area for the wall construction around Poongnatoseong Earthen Castle. For further study, we will make a comparison analysis all kinds of soil characteristics. And then we can understand correctly about wall soils producing area, construction method, repair method and time of Poongnatoseong Earthen Castle.