• Journal of the Mineralogical Society of Korea
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• v.25 no.2
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• pp.77-84
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• 2012

Anatase, one of the $TiO_2$ polymorphs, is known to show different phase transition paths depending on its crystalline and shape. Particle size of 15~25 nm anatase has been subjected to high-pressure Raman spectroscopy and X-ray diffraction studies using a diamond anvil cell. We observe that the starting sample transforms to an amorphous phase above approx. 20 GPa, which is retained upon pressure release to ambient condition. This is in contrast to previously established transition to baddeleyite phase and we suspect difference in the particle distribution state trigger phase instability of nanoparticles and hence amorphization.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.1 s.24
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• pp.47-52
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• 2006

Recently, ship collision accidents account for $20%{\sim}34%$ of domestic marine accidents, also have increased continually. In this paper, therefore we propose the development of Ship Collision A voidance Support program for decreasing ship collision accidents. This program has been developed on the basis of CCAS-Model. A CCAS-Model has ship's maneuvering performance and has been studied for the propose of supporting to avoid ship collision in close quarters. Besides. the program will effectively support maneuvering for collision avoidance through display of the feasible area and the method of collision avoidance using own ship's turning characteristic about action of target ship's keeping course and velocity in various encounter.

• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.365-370
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• 2005

Many sea accidents such as collisions and groundings of vessels were occurred due to the lack of sufficient manoeuvring capability of vessels. Therefore IMO adopted 'The interim standards of ship manoeuvrability by Resolution A.751(18)' and the standards have been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless qf the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standards are divided into three kinds as bellows; (1) Turning capability standards : Estimated values in design stage are to be certified by turning circle test of the actual vessel. (2) Course keeping quality standards : Estimated values in design stage are to be certified by $10^{\circ}\;and\;20^{\circ}$ Zig-Zag tests of the actual vessel. (3) Shortest stopping distance standards : Estimated values in design stage are to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors computed the values of the manoeuvring standards of several vessels from their original design and compared them with those results from experiments of the model ships and also examined the values and concluded about the validity of IMO manoeuvrability standards.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.373-373
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• 2010

광촉매능을 갖는 $TiO_2$는 국내외적으로 많은 연구가 진행되고 있다. 빛의 조사로 발생하는 다양한 물리 화학적 촉매특성이 환경정화 뿐만 아니라 및 에너지 흡수차단 기능도 갖고 있어 최근 주목을 받고 있다. 응용분야로 초친수성 유리제품, 필터, 살균기능의 의료용 부품소재, 고효율 수소생산 및 태양전지 등에 활용성이 커서 친환경에너지 소재로 각광을 받고 있다. 본 연구에서는 초친수성 자동차의 사이드미러 개발을 위해 유리표면에 초친수성 $TiO_2$를 코팅하 고 그의 특성을 평가하였다. 특히, 이종밴드갭을 갖는 복합구조 $TiO_2/Cr_2O_3$/Cr 박막을 스퍼터링법으로 증착하여 중간층인 $Cr_2O_3$의 역할을 고찰하였다. 제조된 박막의 결정구조는 thin film형 X-선회절기(XRD)를 사용하여 분석하였으며, 박막의 표면 미세구조는 FE-SEM(Field Emission Scanning Electron Microscope)와 AFM(Atomic Force Microscope)으로, 화학구조는 XPS(X-ray Photoelectron Spectroscope)로 분석하였다. 친수성 평가는 실온 분위기에서 접촉각 측정기(Topcon-UVR2)를 사용하여 평가 하였으며 이때 조사되는 UV는 파장이 365nm이다. $Cr_2O_3$(비정질)/Cr박막위에 제조된 $TiO_2$ 박막은 균일한 anatase-$TiO_2$가 성장했으나, Cr, $Cr_2O_3$(결정질)박막위에 제조 된 $TiO_2$ 박막은 anatase상과 rulile상이 혼합된 형태로 성장하였다. $TiO_2$/Cr, $TiO_2/Cr_2O_3$(비정질)/Cr, $TiO_2/Cr_2O_3$(결정질)/Cr박막은 UV조사 1시간 만에 $10^{\circ}$ 이하의 초친수성을 나타내었다. 이종 밴드갭을 갖는 $TiO_2/Cr_2O_3$(비정질)/Cr박막은 40시간까지 친수성을 유지하는 결과를 나타냈다.

• Journal of the Mineralogical Society of Korea
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• v.30 no.4
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• pp.187-194
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• 2017

In this study, marble that consist mainly of calcite were used for applicability evaluation after treated with consolidant such as alkoxysilane series of 0.8T0.2E1G_3wt0.08% and 1T1G_7wt0.08%. The position and intensity of X-ray diffraction peaks are no change and increasing trend after treated with two consolidants. The results of scanning electron microscopic analysis, morphology of rope type and homogeneous surface of platy or leaflike form observed on the marble after treated with 0.8T0.2E1G_3wt0.08% and 1T1G_7wt0.08%, respectively. Brightness of surface after treated with consolidant are changing slightly dark. Shore hardness and ultrasonic velocity values show increasing after treated on the marble surface with two consolidants.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.337-343
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• 2023

Olivine is a complete solid solution of fayalite and forsterite that is abundant in Earth and extraterrestrial materials such as rocky planets, meteorites, asteroids, and interplanetary dust. Due to the wide range of olivine compositions, diverse olivine standards are required for quantitative mineralogical analysis of olivine-bearing materials. Olivine standards were synthesized using an electric furnace and stainless steel tubes at temperatures ranging from 1000~1100 ℃. Overall, olivine was synthesized covering the full range of composition, with some synthetic impurities and unreacted material. The synthesized olivine showed a linear increase in the unit cell dimension in proportion to the molar ratio of fayalite in the starting materials, and the diffraction intensity was consistent with that of natural olivine. However, iron-rich synthetic olivine samples tend to have a higher content of impurity, suggesting that not all synthetic olivine can be used as a standard material yet, and improvements in the synthesis process, such as using high purity starting materials and control of reaction time and temperature, are required.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.3
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• pp.193-198
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• 2013

This study proposed a map registration method of a building construction plan drawing with shape matching of cadastral parcel polygon. In general, the drawing contains information about a building boundary and a cadastral parcel boundary. The shape of this cadastral parcel boundary should be same as that of the corresponding parcel polygon object in the KLIS continuous cadastral map. Thus, shape matching between two parcel boundary polygons from the drawing and cadastral map could present transformation parameters. Translation and scaling amounts could be obtained by difference of centroid coordinates and area ratio of the polygons, respectively. Rotation amount could be obtained by the rotation that presents the minimum Turning function dissimilarity of the polygons. The proposed method was applied for building construction plan drawings in eAIS for an urban area in Suwon. To assess positional accuracy of map registration, building polygons in registered drawings and aerial photos were compared. According to the accuracy of the cadastral map which is the reference dataset of the proposed method, the RMSE of corresponding buildings' corners was 0.95m and 2.37m in new and old urban areas, respectively.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.377-393
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• 2010

Pumiceous tuffs occurring in the Beomgockri Group are examined applied-mineralogical characteristics and their controling factors to evaluate their potentials as the adsorption-functional mineral resources. The pumiceous tuffs are diagenetically altered to low-grade zeolitcs and bentonites in the Janggi area. Compositional specialty due to the presence of pumice fragments induces the altered tuffs to exhibit the characteristic adsorption property combined with cation exchange capacity, specific surface area, and acidic pH. Unusual lower pH in the adsorption-functional mineral substances is turned out to be originated from the presence of H-smectite having $H^+$ in the interlayer site of the sheet structure. On account of disordered crystallinity resulting from the exchanged $H^+$ in the interlayer site, the smectite commonly forms crenulated edges in the planar crystal form and exhibits characteristic X-ray diffraction patterns showing comparatively lower intensities of basal spacings including (001) peak than conventional Ca-smectite. Based on the interpretation of paragenetic relations and precursor of the H-smectite, a genetic model of the peculiar clay mineral was proposed. The smectite formation may be facilitated resulting from the precipitation of opal-CT at decreasing pH condition caused by the release of H+ during diagenetic alteration of pumice fragments. Because of the acidic smectite, the low-grade mineral resources from the Beomgockri Group may be applicable to the adsorption industry as the raw materials of acid clays and bed-soil.

• Journal of the Mineralogical Society of Korea
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• v.22 no.1
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• pp.23-34
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• 2009

The adsorption of iodide on untreated bentonite and bentonites modified with organic cation (i.e., hexadecylpyridinium chloride monohydrate ($HDP^+$)) was investigated, and the organobentonites were characterized using uptake measurements, ${\mu}$-XRD, and electrophoretic mobilities measurement. Uptake measurements indicate that bentonite has a high affinity for $HDP^+$. Our ${\mu}$-XRD study indicates that organobentonites significantly expanded in basal spacing and organic cations were substantially intercalated into the interlayer spaces of bentonite. The electrophoretic mobility indicates that organobentonite tht is modified with organic cations in excess of the CEC of bentonite is completely different from untreated bentonite in the surface charge distribution. We found significant differences in adsorption capacities of iodide depending on the bentonite properties as follows: iodide adsorption capacities were 439 mmol/kg for the bentonite modified with $HDP^+$ at an equivalent amount corresponding to 200% of the CEC of bentonite whereas no adsorption of iodide was observed for the untreated bentonite. The molecular environments of iodine adsorbed on organobentonites were further studied using I K-edge and $L_{III}$-edge x-ray absorption spectroscopy (XAS). The X-ray absorption near-edge structure (XANES) of iodine spectra from organobentonites was similar to that of KI reference solution. Linear combination fitting of EXAFS data suggests the fraction of iodine reacted with the organic compound increased with increasing loading of the organic compound on organobentonites. In this study, we observed significant differences in the adsorption environments of iodide depending on the modified property of bentonite and suggest that an organobentonite has potential as reactive barrier material around a nuclear waste repository containing anionic radioactive iodide.

• Journal of the Korean Ceramic Society
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• v.34 no.2
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• pp.145-156
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• 1997

ZrO2 phase transformations depending on the type and amount of dopants and the sintering temperatures were studied for the 2 components (CaO-, Y2O3-, MgO-ZrO2) and the 3 components(MgO-ZrO2-Al2O3)ZrO2 powder by X-ray diffraction and Raman spectroscopy. In the CaO- and Y2O3-ZrO2 systems, as the CaO and Y2O3 contents increased to 6~15mol% and 3~15mol% respectively, we were not able to identify between tetragonal and cubic in the X-ray diffraction patterns. On the other hand, all Raman modes shifted to lower wavenumbers, decreasing in intensity and the number of bands, markedly. These phenomena were caused by tetragonallongrightarrowcubic phase transformation and interpreted by the breakdown of the wave vector selection rule(k=0) and the structural disorder associated with the formation of oxygen sublattice which was caused by the substitution between Zr4+ ion and Ca2+ or Y3+ ion in ZrO2 matrix. The monoclinic to cubic phase transformation occurred in 10mol% MgO-ZrO2 system. As the Al2O3 content increased from 0 to 20mol% in the MgO-ZrO2-Al2O3 systems, cubic phase transformed to monoclinic phase, this is because the MgO didn't play a role in a stabilizer because of the formation of the spinel(MgAl2O4) by the reaction between MgO and Al2O3, Also, the ZrO2 phase transformation was explained by the change of it's lattice parameters depending on the type and amount of dopants. Namely, as the amount of dopant increased to 10~13mol%, the axial ra-tio c/a came close to unity with increasing the lattice parameter a and decreasing the lattice parameter c. At that time, the tetragonallongrightarrowcubic phase transformation occurred.