• 분석과학
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• 제5권1호
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• pp.111-114
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• 1992

$Ba(Zn_{1/3}Ta_{2/3})O_3$는 고온에서 열처리시 Zn과 Ta 이온이 ordering을 일으키며 이때 격자 비틀림이 일어난다. 본 실험에서는 이러한 격자비틀림을 X-선 분말회절법을 사용하여 1/10,000 이상의 정밀도로 측정하였으며, 그 결과 $Ba(Zn_{1/3}Ta_{2/3})O_3$는 $1350^{\circ}C$ 30분 소결시에도 상당한 정도의 격자 비틀림이 발생하며 이러한 격자비틀림은 소결시간이 길어질수록 증가함을 관찰하였다.

• Current Applied Physics
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• 제18권11호
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• pp.1218-1224
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• 2018

Pressure-dependent structural and morphological changes of two amphibole minerals, tremolite and actinolite, were investigated up to 7.0 GPa using synchrotron X-ray powder diffraction underthree different pressure transmission media (PTM): water (W), $CO_2$ and silicone oil (SI). The elastic response of tremolite and actinolite are found to be dependent on the PTM used. When using water (W) as PTM, tremolite and actinolite show normal volume contractions with bulk moduli of 74(1) and 78(1) GPa, respectively. When using $CO_2$ as PTM, we observe the formation of calcite from tremolite above 3.8(1) GPa, whereas actinolite did not show any carbonation reaction. Under silicone oil PTM, we observe modulated volume contraction behaviors in both samples, compared to water and $CO_2$ PTM, with bulk moduli in the order of 90(1) and 94(4) GPa for tremolite and actinolite, respectively.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
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• pp.149-150
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• 2019

• 한국분말재료학회지
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• 제10권1호
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• pp.46-50
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• 2003

Lee et al. reported that a mixture of Cu and Ta, the combination of which is characterized by a positive heat of mixing, $\{Delta}H_{mix}$ of +2 kJ/㏖, can be amorphized by mechanical alloying(MA). It is our aim to investigate to what extent the MA is capable of producing a non-equilibrium phase with increasing the heat of mixing. The system chosen is the binary $Cu_{30}Mo_{70}$ with $\{Delta}H_{mix}$=+19 kJ/㏖. The mechanical alloying was carried out using a Fritsch P-5 planetary mill under Ar gas atmosphere. The vial and balls are made of Cu containing 1.8-2.0 wt.%Be to avoid contaminations arising mainly from Fe when steel balls and vial are used. The MA powders were characterized by the X-ray diffraction, EXAFS and thermal analysis. We conclude that two phase mixture of nanocrystalline fcc-Cu and bcc-Mo with grain size of 10 nm is formed by the ball-milling for a 3:7 mixture of pure Cu and Mo, the evidence for which has been deduced from the thermodynamic and structural analysis based on the DSC, X-ray diffraction and EXAFS spectra.

• 한국표면공학회지
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• 제33권1호
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• pp.25-33
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• 2000

The synthesis and characterization of intercalated compound of dodecanesulfornate into hydrated metal, [M($H_2$O)\ulcorner](C\ulcornerH\ulcorner$SO_3$)$_2$.$xH_2$O (M=Co, Cu) was presented. The compounds shows a layered structure which was determined by powder X-ray diffraction. Thermal behavior of the layered structure was investigated using thermal analysis, and FT-IR spectroscopy by varying the temperature. The increase in layer spacing of the products by increasing the temperature is also checked by X-ray diffraction. We can suggest three kinds of layered structure by varying the temperature, which is accompanied by changing the intercalated dodecanesulfonate from the monolayer to the bilayer structure or changing the tilt angle.

• 분석과학
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• 제20권6호
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• pp.502-507
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• 2007

X 선 회절법은 물질 내부에 원자의 배열 상태를 연구하는데 널리 사용되는 실험 방법으로써 넓은 응용 범위를 가지고 있다. 특히 분말 X 선 회절법은 비파괴적으로 다양한 형태의 시료에 대한 측정이 가능하기 때문에 결정의 배향성, 결정의 크기, 결정 내부의 응력 측정 등에 널리 이용되고 있다. 분말 X 선 회절 방법을 이용하여 혼합물의 성분을 정량적으로 측정하기 위해서는 시료를 구성하고 있는 source 스펙트럼을 도출하고 혼합된 시료의 XRD 스펙트럼에 회귀식을 적합시켜 혼합물 구성비를 얻는 방법이 제안된 바 있다. 그러나 구성성분의 특성상 스펙트럼의 피이크가 폭이 좁고 민감한 경우에는 노이즈의 영향을 받아 도출된 source 스펙트럼이 원래의 순수성분의 형태와 달리 나타날 수 있다. 특히 순수성분 시료를 구할 수 없거나 측정이 불가능한 경우 혼합물 구성비 측정에 어려움이 있다. 본 연구에서는 노이즈 간섭에 의한 source 스펙트럼 도출의 문제를 해결하는 방안으로 비음독립성분분석을 이용하여 혼합된 미지시료로부터 순수한 성분에 해당하는 스펙트럼을 분리해내는 방법을 제안하고자 한다.

• Advances in nano research
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• 제1권4호
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• pp.211-218
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• 2013

A low-cost, green and reproducible citric acid assisted synthesis of nanocrystalline $Al_{0.5}Ag_{0.5}TiO_3$ (n-AAT) powder is reported. X-ray, FTIR, energy dispersive X-ray, transmission electron microscopy and scanning electron microscopy analyses are performed to ascertain the formation of n-AAT. X-ray diffraction data analysis indicated the formation of monoclinic structure. Spherical shaped particles having the sizes of 3-15 nm are found. The mechanism of nano-transformation for the soft-chemical synthesis of n-AAT has been explained using simple organic chemistry rules and nucleation and growth theory. Dielectric study revealed that AAT ceramic might be a suitable candidate for capacitor applications.

• 한국분말재료학회지
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• 제11권3호
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• pp.217-223
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• 2004

Submicron nickel powders were prepared from aqueous solution under hydrothermal condition. The experimental conditions including the types of protective agents, concentration of the solution and the pH were studied in detail. Starting concentration of nickel ion is a dominant factor affecting particle size. It was shown that the subsequent addition of Poly Vinyl Pyrrolidone(PVP) and Sodium Dodecyle Sulfate(SDS) can help to disperse the nickel powder. X-ray diffraction and SEM were employed to characterize the products.

• 한국결정성장학회지
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• 제9권6호
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• pp.580-584
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• 1999

수화된 니켈에 데칸술폰이 층간 삽입된 화합물을 합성한 후 성질을 확인하였다. 화합물의 층상구조는 고온 X-선 회절 데이터로 확인하였다. 온도가 증가하면 층간 삽입된 니켈화합물의 구조가 변하는 것과 동시에 화합물의 층 거리가 24.7 $\AA$에서 30.5 $\AA$가지 증가하였다. X-선 회절 데이터와 데칸술폰의 크기로부터 니켈 층에 결합된 데칸술폰의 공간배열을 결정하였다. 이중 층 구조를 가진 데칸술폰의 분자 축은 니켈 층에 경사진 각도로 수직하게 배열되어있다.

• Bulletin of the Korean Chemical Society
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• 제9권5호
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• pp.280-282
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• 1988

The structural, electrical and magnetic properties were investigated for the high-Tc superconductor $YBa_2Cu_3O_{7-x}$, where x was 0.13. The results of temperature dependence of the resistivity and the magnetization in $YBa_2Cu_3O_{6.87}$ whose structure and phase are confirmed by arialysis of X-ray powder diffraction pattern have been reported. A very sharp superconductivity transition appears at 92K in the specimen whose chemical composition is determined from redox titration, strongly suggesting that this specimen consists of a single-phase superconductor. From the results of X-ray diffraction analysis, magnetization curves, levitation and resistance measurements, it is suggested that the observed superconductivity is bulk property in nature and that the $YBa_2Cu_3O_{6.87}$ phase is responsible for the superconductivity of the present reproducible specimen.