• Title/Summary/Keyword: X-ray 회절법

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Crystal Structure Analysis of $LiN(D_xH_{1-x}){_4}SO_4$ by X-ray and Neutron Diffraction (X-선과 중성자 회절을 이용한 강유전체 단결정 $LiN(D_xH_{1-x}){_4}SO_4$의 결정구조 연구)

  • Kim, Shin-Ae;Kim, Seong-Hoon;So, Ji-Yong;Lee, Jeong-Soo;Lee, Chana-Hee
    • Journal of the Mineralogical Society of Korea
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    • v.20 no.4
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    • pp.351-356
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    • 2007
  • The crystal structure of $Li(ND_4)SO_4$ was analyzed by X-ray and neutron diffraction methods. The crystal is a deuterated $Li(NH_4)SO_4$ and one of the ferroelectric materials with hydrogen atoms. The crystal is orthorhombic at room temperature, $P2_1nb$, with lattice parameters of $a=5.2773(5)\;{\AA},\;b=9.1244(23)\;{\AA},\;c=8.7719(11)\;{\AA}$ and Z=4. Neutron intensity data were collected on the Four-Circle diffractometer (FCD) at HANARO in Korea Atomic Energy Research Institute and X-ray date were given by Prof. Y. Noda of Tohoku University Japan. The structure was refined by full-matrix least-square to final R value of 0.070 for 1450 observed reflections by X-ray diffraction and to final R=0.049 for 745 observed reflections by neutron diffraction. With X-ray data we obtained only one hydrogen atomic position. However, not only all atomic positions of four hydrogen atoms at $NH_4$ but also the occupation factors of D and H were refined with neutron data. From this results we obtained the average chemical structure of this sample, $LiND_{3.05}H_{0.95}SO_4$.

The X-Ray Study on Macrostress and Microstress for Two-Phase Stainless Steel (二相스테인리스鋼의 X線에 의한 巨視的.微視的 應力에 關한 硏究)

  • ;;廣賴幸雄
    • Journal of Welding and Joining
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    • v.12 no.4
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    • pp.141-150
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    • 1994
  • The residual stress is inevitably introduced into composites because of the mismatch of the coefficient of thermal expansion, and it is different in each phase. The X-ray technique can detect separately the stress in each phase, so will wield useful information for analyzing the toughening mechanisms of composites. In order to apply the law of mixture to alloy steels with composite microstructures, two phase stainless steel, consisted of ferrite (.alpha.-Fe) and austenite (.gamma.-Fe) structures, was selected. The tensile elastic deformation was loaded, and then the X-ray diffraction technique was used to measure the X-ray elastic constants, the X-ray stress constants and the phase stresses. The law of mixture was investigated and the separation of macrostress and microstress was carried out. The phase stresses (the residual stresses of phase) in each phase, which were measured by X-ray technique, was directly proportional to the applied stress. The macrostress calculated from the phase stresses by using the law of mixture was nearly equal to the applied stress.

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Elastic Moduli Determination of MgO Using Ultrasonic Interferometry (초음파 간섭법을 이용한 MgO 단결정의 체적탄성률 측정)

  • Kim, Young-Ho
    • Journal of the Mineralogical Society of Korea
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    • v.13 no.3
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    • pp.138-146
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    • 2000
  • Using the ultrasonic interferometry on the single crystal MgO-periclase, adiabatic bulk moduli were determined to be 163.2 GPa and 162.6 GPa from (100) and (110) lattice plane measurements, respectively. Density was measured on polycrystalline MgO by the X-ray diffraction technique. Results from this study were compared with the previously reported values. Further, the present results were converted to the isothermal bulk moduli and, then compared with the published data available including the energy dispersive X-ray diffraction result which was performed on the same single crystal MgO. The principle and techniques ultrasonic interferometry were introduced too.

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Correction Method of the Hydrogen Bond-Distance from X-ray Diffraction: Use of Neutron Data and Bond Valence Method (X-선 회절로 얻은 수소결합의 결합거리 보정 방법: 중성자 회절결과와 결합원자가 방법 이용)

    • Journal of the Mineralogical Society of Korea
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    • v.16 no.1
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    • pp.65-73
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    • 2003
  • In this study we have derived the two correction methods of hydrogen bonding distance. In case of the intermediate or long hydrogen bond(>2.5 $\AA$), hydrogen bonding distances can be corrected by using the function d(O-H)=exp((2.173-d(O…O))/0.138)+0.958 obtained by least- squares fit to the data from the neutron diffraction at low temperatures. The valence-least-squares method is effective for the distance correction of very short hydrogen bond(<2.5 $\AA$). The distance correction is necessary for the long intermolecular hydrogen bond obtained from X-ray diffraction analysis.

Phase identification and degree of orientation measurements far fine-grained rock forming minerals using micro-area X-ray diffractometer -$Al_{2}SiO_{5}$ Polymorphs- (미소부 X-선 회절분석기를 이용한 미립조암광물의 상동정 및 배향도 측정 -$Al_{2}SiO_{5}$ 3상다형-)

  • 박찬수;김형식
    • The Journal of the Petrological Society of Korea
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    • v.9 no.4
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    • pp.205-210
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    • 2000
  • Measurements of phase identification and degree of orientation for fine-grained (about 0.3 mm in diameter) minerals in rock samples performed by micro-area X-ray diffractometer.$Al_{2}SiO_{5}$ polymorphs (andalusite, kyanite and sillimanite) were chosen for the measurements and target minerals were existed on thin sections. Micro-area X-ray diffractometer is composed of 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillating goniometer and position sensitive proportional counter (PSPC). $CuK_{\alpha}$ radiation was used as X-ray source and a pin hole ($50\;\mu\textrm{m}$$ in diameter) collimator was selected to focus radiation X-ray onto the target minerals. Phase identification and diffracted X-ray peak indexing were carried out by 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillation measurement. Then, 2(${\omega}\;{\phi}$)-circle oscillation measurement was made for the purpose of searching the prevailing lattice plane of the minerals on thin section surface. Finally, for a selected peak by 2-circle oscillation measurement, X-ray pole figure measurement was executed for the purpose of check the degree of orientation of the single lattice direction and examine its pole distribution. As a result of 3-circle oscillation measurement, it was possible that phase identification among $Al_{2}SiO_{5}$ polymorphs. And from the results of 2-circle oscillation measurement and X-ray pole figure measurement, we recognized that poles of andalusite (122), kyanite (200) and sillimanite (310) lattice plances were well developed with direction normal to each mineral surface plane respectively. Therfore, the measurements used with micro-area X-ray diffractometer in this study will be a useful tool of phase identification and degree of orientation measurement for fine-grained rock forming minerals.

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Microscopic analysis of gas hydrates using X-ray diffraction method (X-ray diffraction을 이용한 가스 하이드레이트 미세구조 분석)

  • Lee, Jong-Won;Seol, Ji-Woong;Koh, Dong-Yeun;Lee, Huen
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.10a
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    • pp.178-181
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    • 2008
  • 다양한 조성을 갖는 $CH_4+CO_2$ 혼합 기체 하이드레이트 샘플의 미세 구조 분석을 위하여 X-ray 회절 방법을 이용하였다. X-ray 회절 분석을 이용할 경우, 하이드레이트로의 전환율과 같은 정성적인 분석뿐 아니라 각 객체별 cage occupancy와 같은 정량적인 분석까지도 가능한 것으로 나타났다. 또한 이렇게 얻어진 X-ray 회절 분석 결과 및 refinement 결과를 $^{13}C$ 고체 NMR 방법과 교차 비교함으로써 측정 결과의 신뢰도를 높이려 하였다. 얻어진 분석 결과는 이후 가스 하이드레이트를 이용한 다양한 연구 분야에서 저장용량 평가 및 객체 점유율과 같은 미세 구조 정보를 얻는 데에 유용하게 사용될 것으로 전망된다.

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A Study on the Measurement of Residual Stress in Rolled Steel for Automobile using X-ray Diffraction (X선 회절을 이용한 자동차 압연강의 잔류응력 측정에 관한 연구)

  • 홍순혁;이동우;조석수;주원식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.6
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    • pp.150-157
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    • 2002
  • In textured material, diffraction angle $2{\theta}$ usually shows a nonlinear relation against $sin^2{\psi}$ due to elastic anisotropy of crystals. SPHD and SPCD steel is cold-rolled carbon steel for automobile. The characteristics X-ray for stress measurement is Cr $K_{\alpha}\;and\;Mo\;K_{\alpha}$ characteristic X-ray. The $2{\theta}-sin^2{\psi}$ diagram under elastic strain seems to have a linear behavior using regression line of data but has a nonlinear behavior in distribution of data by Cr $K_{\alpha}$ characteristic X-ray. As the plastic strain of specimen increases, the nonlinearity of $2{\theta}$ with respect to $sin^2{\psi}$ increases remarkably. On the other hand, the diffraction angle $2{\theta}$ by Mo $K_{\alpha}$ characteristic X-ray shows a good linearity on $2{\theta}-sin^2{\psi}$ diagram under plastic strain as well as elastic strain. Therefore, this paper presents the measurement of residual stress in cold-rolled carbon steel for automobile using penetration depth of Mo $K_{\alpha1}$ characteristic X-ray and multiplicity factor of crystal diffraction plane.

X-Ray Diffraction Study on the Cellulose Structures in Wood Cell Wall (X선 회절법을 이용한 목재세포벽중의 셀룰로오스의 구조해석)

  • 김남훈;이선호
    • Journal of Korea Foresty Energy
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    • v.18 no.2
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    • pp.62-69
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    • 1999
  • Lignin in wood cell walls influeced the transformation of the cellulose crystal structure during mercerization. Samples of sound and decayed woods by white rot fungus of Quercus mongolica were treated with 20% aquous NaOH solution, followed by washing and drying, and delignified. The effect of delignification on cellulose structure was investigated by a series of an X-ray diffraction analysis and ultraviolet(UV) microscopy. Delignification of alkali-treated woods did not influence their cellulose crystal structures. It may be concluded that lignin prevents the swelling of wood cellulose during mercerization and restrain the intermingling of cellulose chains.

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Determination of mixing ratios in a mixture via non-negative independent component analysis using XRD spectrum (XRD 스펙트럼의 비음독립성분분석을 통한 혼합물 구성비 결정)

  • You, Hanmin;Jun, Chi-Hyuck;Lee, Hyeseon;Hong, Jae-Hwa
    • Analytical Science and Technology
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    • v.20 no.6
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    • pp.502-507
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    • 2007
  • X-ray diffraction method has been widely used for qualitative and quantitative analysis of a mixture of materials since every crystalline material gives a unique X-ray diffraction pattern independently of others, with the intensity of each pattern proportional to that material's concentration in a mixture. For determination of mixing ratios, extracting source spectra correctly is important and crucial. Based on the source spectra extracted, a regression model with non-negativity constraint is applied for determining mixing ratios. In some mixtures, however, X-ray diffraction spectrum has sharp and narrow peaks, which may result in partial negative source spectrum from independent component analysis. We propose several procedures of extracting non-negative source spectra and determining mixing ratios. The proposed method is validated with experimental data on powder mixtures.

Phase Analysis of Mechanically Alloyed $\sigma$-VFe Alloy Powders by Neutron and X-ray Diffraction (기계적 합금화한 $\sigma$-VFe합금의 중성자 및 X선 회절에 의한 상분석)

  • 이충효;조재문;이상진;심해섭;이창희
    • Korean Journal of Materials Research
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    • v.11 no.8
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    • pp.664-664
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    • 2001
  • The mechanical alloying (MA) effect in $\sigma$-VFe intermetallic compound was studied by neutron and X-ray diffraction. The structure of MA $\sigma$-VFe powders were characterized by the X- ray diffraction with Cu- $K\alpha$ radiation and neutron diffraction with monochromatic neutrons of $1.835\AA$ using a high resolution powder diffractometer (HRPD). Mechanical alloying of $\sigma$-VFe compound gives rise to a dramatic structural change. After 60 hours of MA, the Fe-Fe distribution of the $\sigma$- phase VFe tetragonal structure with 30 atoms in a unit cell is found to change into that of the $\sigma$-(V,Fe) solid solution with bcc structure, which is a stable phase at elevated temperature above $1200^{\circ}C$. A comparison of X-ray diffraction data for the $\alpha$-phase has been also made with the corresponding neutron diffraction data. The (101) and (111) diffraction peaks of the $\sigma$-phase was clearly observed only in neutron diffraction pattern, which is believed to be a characteristic feature due to the chemical atomic ordering of $\sigma$- VFe phase.