• Bulletin of the Korean Chemical Society
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• 제30권1호
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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.

• 한국결정성장학회지
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• 제26권1호
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• pp.49-52
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• 2016

본 연구에서는 AlN 결정 성장시 중요한 공정변수 중의 하나인 성장 압력과 온도 조건에 따라 다르게 성장되는 AlN 결정상의 결과에 대하여 고찰하였다. AlN 결정 성장은 6H-SiC 종자 결정을 사용하여 PVT(Physical Vapor Transport)법을 적용하여 성장시켰다. 성장 압력과 온도에 따라 AlN 결정의 특성이 변화하였고, Raman 분석을 통해 다양한 방향을 갖는 AlN 결정이 SiC 종자 결정 위에 성장되는 것을 확인하였다.

• 한국결정성장학회지
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• 제12권2호
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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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• 제34권2호
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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.

• 한국지반환경공학회 논문집
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• 제7권6호
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• pp.5-12
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• 2006

본 연구는 struvite 결정화 적용시 $Mg^{2+}$과 $PO_4{^{3-}}$의 주입량, pH, 반응시간 그리고 결정핵 주입과 같은 실험인자가 혐기성 발효액의 질소 및 인 제거에 미치는 영향을 실험적으로 검토하였다. $Mg^{2+}:NH_4{^+}:PO_4{^{3-}}$의 적정 주입 몰비는 1.2:1.0:1.2 였다. 최적 주입 몰비에서 $NH_4{^+}-N$와 $PO_4{^{3-}}-P$의 평균제거율 및 반응속도상수는 각각 79.2, 96.8%, 0.157 그리고 $0.344min^{-1}$였다. 최적 pH는 11이었으며 반응시간 10분 이내에 충분히 struvite 결정화가 이루어 졌다. 결정핵 주입 유 무에서 결정핵 주입량 1g/L에서 가장 낮은 영양염류 잔류농도 값을 보여주었으며, SEM 사진 분석 결과 결정핵의 성장을 관찰할 수 있었다. 또한 struvite 침전물의 XRD 분석 결과 사방정계 결정구조를 가지는 것으로 확인되었다.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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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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• 제35권6호
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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.

• 분석과학
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• 제18권4호
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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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• 제27권5호
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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.

• 헤리티지:역사와 과학
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• 제45권4호
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• pp.114-125
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• 2012

본 연구에서는 풍납토성 동성벽 내부토양을 대상으로 색도색차계, XRD, 입도분석기 등을 이용하여 색도, 입도, 주요화학조성, 광물결정구조 등을 분석하였다. 성벽토양은 황갈색, 회황색의 모래 또는 실트질 모래(SW~SC)로 분류되고, 입도와 화학 광물학적 특성이 유사하며, 도로나 활주로 등의 성토재료로 적합한 특성임이 확인되었다. 색도, 입도, 화학조성, 강열감량의 4인자를 기준으로 비교분석한 결과, 풍납토성이 위치한 지역의 대조군 토양(PNS)은 성벽축조에 사용되지 않았던 것으로 판단한다. 모든 토양은 풍납토성이 위치한 지역과 지질학적으로 유사한 곳에서 채굴되었던 것으로 추정되지만, 성벽 축조 이전에 분포했던 구지표면의 토양과는 다른 특성을 나타내기 때문에, 유적 주변에 대량채굴이 가능했던 토양분포지가 존재할 것으로 추정된다. 향후 성벽 축조재료의 여러 특성들을 비교 분석하면, 성벽 내부토양의 산지, 축조방법, 보수방법 및 시기 등을 보다 종합적으로 이해할 수 있는 계기가 마련될 것으로 기대한다.