• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1885-1891
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• 2023

The present work aims to fabricate Na_1+xZr₂Si_xP_3-xO₁₂ compound at various calcination temperatures based on the zircon mineral. The fabricated compound was calcinated at 250, 500, and 1000℃. The effect of calcination temperature on the structure, crystal phase, and radiation shielding properties was studied for the fabricated compound. The X-ray diffraction diffractometer demonstrates that, the monoclinic crystal phase appeared at a calcination temperature of 250℃ and 500℃ is totally transformed to a high-symmetry hexagonal crystal phase under a calcination temperature of 1000℃. The radiation shielding capacity was also qualified for the fabricated compounds using the Monte Carlo N-Particle transport code in the g-photons energy interval between 15keV and 122keV. The impacts of calcination temperature on the g-ray shielding behavior were clarified in the present study, where the linear attenuation coefficient was enhanced by 218% at energy of 122keV, when the calcination temperature increased from 250 to 1000℃, respectively.

• 한국결정성장학회지
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• 제18권1호
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• pp.38-44
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• 2008

c-축 배향을 갖는 MFI 제올라이트 필름$(<35{\mu}m)$을 종자결정 성장법을 이용하여 실리카라이트-1 종자결정이 도포된 알루미나와 실리콘 지지체 위에 성장시켰다. 지지체 표변에서 성장된 필름은 전자현미경과 X- 회절 분석을 이용하여 조사하였다. 지지체 표면의 거친 정도에 따른 필름의 성장에 미치는 영향에 대해서 조사하였으며 c- 축 배향을 갖는 필름과 종자결정 성장법에서 나타나는 특징적인 돔 형태의 결함구조의 생성과 반응기구에 대해서 설명하였다. 지지체 표면의 거친 정도가 c- 축 배향에 중요한 역할을 하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.124-127
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• 2003

The stochiometric $AgGaSe_2$ polycrystalline mixture of evaporating materials for the $AgGaSe_2$ single crystal thin film was prepared from horizontal furnance. To obtain the single crystal thin films, $AgGaSe_2$ mixed crystal and semi-insulating GaAs(100) wafer were used as source material and substrate for the Hot Wall Epitaxy (HWE) system, respectively. The source and substrate temperature were fixed at $630^{\circ}C$ and $420^{\circ}C$, respectively. The thickness of grown single crystal thin films is $2.1{\mu}m$. The single crystal thin films were investigated by photoluminescence and double crystal X-ray diffraction(DCXD) measurement. From the photoluminescence measurement of $AgGaSe_2$ single crystal thin film, we observed free excition ($E_x$) observable only in high quality crystal and neutral bound excition ($D^{\circ}$,X) having very strong peak intensity. And, the full width at half maximum and binding energy of neutral donor bound excition were 8 meV and 14.1 meV, respectively. By Haynes rule, an activation energy of impurity was 141 meV.

• 센서학회지
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• 제7권6호
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• pp.386-393
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• 1998

비선형광학 단결정 KTP에 대해 고온 분말 X-선 회절실험과 복소 유전상수 측정실험 등을 수행하였다. 고온분말 X-선 회절 실험 결과를 Lipson과 Cohen의 해석적 방법을 사용하여 분석하였으며, 그 결과 $900^{\circ}C$ 이하의 온도에서는 어떠한 구조상전이도 없음을 확인하였다. 그리고 KTP는 $900^{\circ}C$ 이상에서 구조상전이가 있으며, 상전이 온도 이상의 온도영역에서도 직방정계(orthorhombic)에 속함을 확인하였다. 한편, 복소 유전상수 측정결과를 현상론적인 유전완화식에 적용하였으며, 이로부터 $K^+$ 이온의 hopping에 의한 KTP의 유전완화 mechanism은 $-78^{\circ}C$부터 $200^{\circ}C$까지 단일모드로 Cole-Cole relation을 만족함을 알았다. 이때 완화시간은 Vogel-Fulcher relation을 따르고 있으며, $200^{\circ}C$ 이상의 온도영역에서는 hopping mechanism과 더불어 열적으로 활성화된 확산 mechanism이 KTP의 전도특성을 지배하는 것으로 보인다.

• 한국결정성장학회지
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• 제32권6호
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• pp.225-230
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• 2022

p-XBP4 (N,N'-p-phenylenedimethylenbis(pyridin-4-one)), Cs₃[W(CN)₈]와 Tb(NO₃)₃·6H₂O를 사용하여 2차원의 이중 상호 침투 구조를 갖는 새로운 Tb-MOF인 [Tb(p-XBP4)_2.5(H₂O)₂]·W(CN)₈를 합성하였다. 단결정 X선 회절 분석법으로 얻어진 구조 정보를 통해 Tb-MOF는 이중 상호 침투된 독특한 2차원 구조임을 확인하였다. 또한, 적외선 분광 분석법, 단결정 및 분말 X-선 회절 분석법을 활용하여 추가적인 특성 분석을 수행하였다. Tb-MOF가 갖는 자성 특성과 분자 자석으로서의 거동 가능성을 조사하기 위해, 직류 자화율 및 교류 자화율을 측정하고 이를 분석하였다.

• Archives of Pharmacal Research
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• 제2권2호
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• pp.99-110
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• 1979

The crystal structure of sulfapyridine, $C_{11}H_{11}N_{3}O_{2}S$, has been determined by X-ray diffraction method. The compound crystallizees in the monoclinic space group C2/c with a = 12, 80(4), b= 11.72(4), $c= 15.36(5){\AA}, {\beta}= 94(3)^{\circ}$and Z = 8. A total of 1133 observed reflections were collected by the Weissenberg method with CuKaradiation. Structure was solved by the heavy atom method and refined by isostropic block-diagonal least-squares method to the R value of 0.14. The nitrogen in the pyridine ring of sulfapyridine is associated with an extra-annular hydrogen. The C (benzene ring) S-N-C (pyridine ring) group adopts the gauche form with a fonformational angle of $71^{\circ}$. The benzene ring are inclined at angle of $84^{\circ}.to the pyridine ring plane. Sulfapyridine shows three different hydrogen bonding in the crystal. They are two N-H...O hydrogen bonds with the distance of 2.90 and 2.98${\AA}$ respectively, and on N-H...N with the distance of 3.06 ${\AA}$.

• 대한화학회지
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• 제63권1호
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• pp.29-36
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• 2019

A potentially tetradentate Schiff base ligand, 2-((2-((pyridin-2-ylmethylene)amino)ethyl)amino)ethan-1-ol (PMAE), and its cadmium(II) complex, [$Cd(PMAE)I_2$] (1), were prepared and characterized by elemental analysis, FT-IR, Raman, $^1H$ and $^{13}C$ NMR spectroscopies and single-crystal X-ray diffraction. In the crystal structure of 1, the cadmium atom has a slightly distorted square-pyramidal geometry and a $CdN_3I_2$ environment in which the PMAE acts as an $N_3$-donor. In the crystal packing of the complex, the alcohol and amine groups of the coordinated ligands participate in hydrogen bonding with iodide ions and form $R^2{_2}(14)$ and $R^2{_2}(8)$ hydrogen bond motifs, respectively. In addition to the hydrogen bonds, the crystal network is stabilized by ${\pi}-{\pi}$ stacking interactions between pyridine rings. The thermodynamic stability of the isolated ligand and its cadmium complex along with their charge distribution patterns were studied by DFT and NBO analysis.

• 분석과학
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• 제11권1호
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• pp.42-46
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• 1998

고리화펜타디엔이 ${\pi}$-결합된 최초의 비스무트 화합물$({\eta}^5-C_5Me_5)_2BiCl$이 에데르 용매하에서 칼륨펜타메틸고리화펜타다이엔과 삼염화비스무트의 반응결과 짙은 보라색의 결정이 30%의 수율로 얻어졌다. 이 화합물의 분해 생성물로서 pentamethylcyclopentadienylbismuth chloride($PCpBiCl_2$)가 얻어졌으며 $({\eta}^5-C_5Me_5)_2BiCl$은 칼륨펜타메틸고리화펜타다이엔과 $-78^{\circ}C$에서 반응하지 않음을 확인하였다. $({\eta}^5-C_5Me_5)_2BiCl$의 구조가 192K에서 X선 단결정 구조분석 방법에 의해 밝혀졌다: triclinic crystal, space group p1, Z=2. $C_{20}H_{30}$의 이탈반응이 확인되었으며 고리화펜타다이엔의 두 고리가 C-C ${\sigma}$-단일 결합으로 이루어져 있다는 것이 X선 단결정 구조분석 방법에 의해 밝혀졌다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 가을 학술발표회 논문집
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• pp.1-4
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• 1992

This paper deals with the effect of siliceous slurry coating on concrete microstructure under damp environment. This material is mixed inorganic powder consisted of silica, cement and fine sand and water. Water pressure was given on the coated surface of concrete. for estimation on effect of siliceous slurry coating, microstructure of coated concrete was observed through SEM, and chemical components of crystals were analyzed with X-ray diffraction and EDX. A number of needle and fibrous crystals were produced in microstructure. And based on X-ray diffraction and EDX, needle crystal mainly consist of Al, Si, and Ca, and it is concluded to be ettringite. Fibrous crystals consist of Ca and Si, and it to be calcium silicate hydrate.

• Journal of Pharmaceutical Investigation
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• 제20권1호
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• pp.35-42
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• 1990

A new form of sulfabenzamide was characterized using X-ray diffraction patterns and differential scanning calorimetry. Solubility studies demonstrated that, of the sulfabenzamide polymorphs, the new form was more soluble than form I. Compression of the new form at compression force of 1000 $kg/cm{^2}$ didn't induce polymorphic change in the crystal. Similar patterns were also produced through grinding. The effects of some diluents on the polymorphic transformation from the new form into form I by grinding and compression were also studied. Three diluents, $Avicel^{\circledR}$, lactose and starch showed no influence on the polymorphic transformation. The new form seemed to be more suitable for the pharmaceutical preparation.