• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.208-215
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• 2009

As a fundamental study to develop absorbing materials on harmful volatile organic compounds (VOC) such as formaldehyde, structural and crystalline characteristics of MDF carbonized at different temperatures were examined by a scanning electron microscope and an X-ray diffraction method. Fibers in surface layer of MDFs showed more compressed morphology than those in middle layer of MDFs, but the porosity of MDFs increased with increasing the carbonized temperature. The wrinkle shape was frequently surfaces of cell walls was more severe than that at the lumina of cells. The shape of pits in the fibers of carbonized MDFs were hardly changed. The cell walls of MDFs carbonized at $400^{\circ}C$ and over showed an amorphous-like structure without cell layering. X-ray diffratograms from the MDFs carbonized at $400^{\circ}C$ showed a trace of crystalline cellulose. On the other hand, an amorphous diffraction pattern from carbons was obtained with the MDFs carbonized at $1,000^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.30 no.1
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• pp.40-47
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• 2002

This study was carried out to investigate the dimensional stability of three softwoods (Pinus densiflora S. et Z., Pinus koraiensis S. et Z., Larix kaempferi C_ARR.) and two hardwoods(Quercus mongolica F., Quercus variabilis B_L.) treated with polyethylene glycol(PEG). Existence of PEG in wood was examined by an X-ray diffraction method. Shrinkage of the sample woods decreased with increasing concentration of PEG. The dimensional stability of five species had improved highly in thirty percent solutions of PEG with molecular weight 1000~4000, and the dimension of PEG-treated softwoods was more stable than that of PEG-treated hardwoods. Weight gain and bulking effect of the woods treated with PEG increased with increasing concentration of PEG. X-ray diffractograms of Pinus koraiensis wood treated with PEG showed two peaks derived from PEG crystal at 2𝜃 = 19° and 2𝜃 = 23°. However, the diffractograms of Quercus mongolica wood did not present any peaks caused by PEG crystal. From the result of X-ray diffraction, it was revealed that the content of PEG in Pinus koraiensis wood was higher than that in Quercus mongolica wood.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.5
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• pp.431-438
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• 2022

In functional materials, in situ experimental techniques as a function of external stimulus (e.g., electric field, magnetic field, light, etc.) or changes in ambient environments (e.g., temperature, humidity, pressure, etc.) are highly essential for analyzing how the physical properties of target materials are activated/evolved by the given stimulation. In particular, in situ electric-field-dependent X-ray diffraction (XRD) measurements have been extensively utilized for understanding the underlying mechanisms of the emerging electromechanical responses to external electric field in various ferroelectric, piezoelectric, and electrostrictive materials. This tutorial article briefly introduces basic principles/key concepts of in situ electric-field-dependent XRD analysis using a lab-scale XRD machine. We anticipate that the in situ XRD method provides a practical tool to systematically identify/monitor a structural modification of various electromechanical materials driven by applying an external electric field.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.144-148
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• 1997

the molecular and crystal 3-dimensional structure of bentazone, C10H12N2O3S, has been determined from single crystal x-ray diffraction study. Crystal system is monoclinic: a=8.7817(9)Å, b=9.6059(9) Å, c=13.574(9) Å, β=97.269(1)', V=1136.1(6)Å, space group : P21/c, z=4. The molecular structure model was solved by direct method and refined by full matrix least squares. The final reliable factor, R, is 0.045 for 1396 independent reflections(Fo2>4σFo2). A molecule has a staggered conformation with thiocarbazin ring and isopropyl functional group and the molecules by hydrogen bonds are cross stacked along the c-axis.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.258-265
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• 2001

Turbine blade is subject to force of three type ; torsional force by torsion-mount, centrifugal force by rotation of rotor and cyclic bending force by steam pressure. Cyclic bending force of them is main factor on fatigue fracture. In the X-ray diffraction method, the change in the values related to plastic deformation and residual stress near the fracture surface mat be determined, and information of internal structure of material can be obtained. Therefore, to find a fracture mechanism of torsion-mounted blade in nuclear plant, based on the information from the fracture surface obtained by fatigue test, the correlation of X-ray parameter and fracture mechanics parameter was determined, and then the load applied to actual broken turbine blade parts was predicted. Failure analysis is performed by finite element method and Goodman diagram on torsion-mounted blade.

• Journal of the Korean Vacuum Society
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• v.2 no.2
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• pp.171-180
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• 1993

X-ray photoelectron diffraction (XPD) is used to characterize the crystallographically cleaved GaAs(110) surface. By using polar and azimuthal scans of the usual angle-resolved x-ray photoelectron spectroscopy, we get the reconstruction geometry of the clean GaAs(110) surface from the intensity ratio of Ga 3d core-level peaks. The reconstruction parameters are determined by fitting the diffraction pattern with the single scattering cluster (SSC) model, and the results show similar tendencies to those obtained by other techniques.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.72-79
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• 1996

Cellulose I에서 Cellulose II로의 결정변태기구를 X선 및 전자선 회절법과 현미경적 방법을 이용하여 구명하였다. X선 회절 결과, Na-cellulose I을 고온에서 수세할 경우 Cellulose I과 Cellulose II의 혼합형 회절도가, 저온에서 수세할 경우 Na-cellulose IV의 회절도가 얻어졌다. 전자선회절 결과, 고온수세의 시료는 Cellulose I과 Cellulose II의 혼합형이 저온수세의 시료는 Cellulose II의 회절도가 얻어졌다. 또한 고온수세 시료의 전자선회절도로부터 섬유벽의 내측부가 외측부보다 재생 Cellulose I의 양이 많은 것이 확인되었다. 따라서 알칼리 팽윤시 섬유벽내에는 불완전한 팽윤이 발생하는데 그 정도는 내측부가 더욱 심한 것으로 생각된다. 이때 형성되는 불완전한 Na-cellulose I 은 고온 수세의 경우는 탈수에 의해 Cellulose I로, 저온수세의 경우는 수화에 의해 Cellulose II로 변태되지만 완전히 팽윤된 Na-cellulose I은 Cellulose I로 재생될 수 없는 것으로 생각된다. 현미경적 실험결과, mercerization과정에서 cellulose 분자쇄의 packing이나 conformation의 변화와 관련하여 microfibril 의 흐트러짐은 발생하지 않는 것으로 생각되었다.

• Journal of the Korean Magnetics Society
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• v.10 no.4
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• pp.183-190
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• 2000

This study aims at making a research into the physical and chemical properties of the neolithic era potterys, which are unearthed from Gosanli, Sagaeli, Bukchonli, Samyangdong and Gonaili districts in Cheju Island, by using X-ray diffraction, X-ray fluorescence spectrometer and Mossbauer spectroscopy. This results are as follows. The principal component of five plain coarse pottery sherds by X-ray fluorescence spectrometer and X-ray diffraction spectrum at the room temperature is silicate mineral which is equal to SiO$_2$, and they also have a little magetite, hematite and goethite. The most existent Fe is Fe$\^$+3/ through Mossbauer spectroscopy analysis of plain coarse pottery sherds and it is presumed that the magnetic hyperfine splitting caused this result. The ratio of Fe$\^$2+//(Fe$\^$2+/+Fe$\^$3+/) is mostly zero by Mossbauer spectrum at the room temperature of plain coarse pottery sherds and it is thought because they were fired in the atmosphere.

• Korean Journal of Crystallography
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• v.4 no.1
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• pp.25-35
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• 1993

Tetra-tert-butyl-tetrapropionycalix (4) arena (C56H7208) is Triclinic, space group Pl, with a=13.664(5), b=17.585(5), c=12.863(2)A, a=109.33(2), B=111.97(2), γ=76.45(3) ˚, Z=2, V=2684.08A3, D, =1.152g/cm3, Dm=1.15g/cm3. The intensity data were collected on an Enraf-Nonius CAD-4 Diffractometer with a graphite monochromated Mo-Ka radiation. The structure was solved by direct methods and refined by leastsquares methods. The final R factor was 0.084 for 2561 observed reflections. The configuration of the molecule from the X-ray crystallographic investigation has the partial cone conformation, three tort-butylphenyls are down and a tort-butylphenyl is up. Three propionyloxy groups direct toward the exterior of the macrocycle cavity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.2
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• pp.167-175
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• 1993

Lithium-Carbon Intercalation Compounds(Li-CICs) have been synthesized from various carbon ma-terials by use of the modified stainless steel two-bulbs methods. These compounds had various colours by structural character of starting materials. The synthesized Li-CICs were identified to stage formation process by X-ray diffraction data. At these results, well-oriented natural graphite and graphite fiber are formed lower stages(Stage 1, Stage 2), but poor-oriented carbon fiber and petroleum cokes are also formed higher stages(Stage 3, Stage 4, Stage 5). And when we compared with measured d value and calculated d value, these values agreed with each other. But poor-oriented carbon materials are some difference from them. The stage stability and energy stage of Li-CICs were obtained by UV/VIS Spectrophotometric data. X-ray diffraction and UV/VIS Spectrophotometric data suggested that well-oriented carbon materials has distingushible curve between energy and reflectance. In these results, we know that many charge carriers between carbon layers are related to concentration of intercalants. And then, this paper also provides information on high efficiency energy storing materials at intercalation process of Li-CICs.