• Title/Summary/Keyword: X-Ray Diffraction

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Semi-quantitative Analysis of Manganese Oxide Mineral in Manganese Nodule From the East Siberian Sea (동시베리아해 망가니즈단괴의 산화망가니즈광물 반정량 분석)

  • Yu, Hye Jin;Shin, Eun Ju;Koo, Hyo Jin;Cho, Hyen Goo
    • Korean Journal of Mineralogy and Petrology
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    • v.33 no.4
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    • pp.427-437
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    • 2020
  • Manganese nodules, which are evaluated as potential metal resources, have been found in the Arctic Ocean as well as in the abyssal plains of the Pacific and Indian Oceans. Manganese nodules exhibit strong variations in the morphology, internal texture, chemical composition and mineralogy as they grow. The relationship between the texture and chemical elemental composition during the growth process is well documented, but the mineral composition variation during the growth process is not. Because the manganese oxide minerals in nodules are fine-grained and poorly crystalline, quantitative analysis for the mineral composition is challenging for the bulk nodule sample. This study investigated the internal texture and Mn-oxide mineral composition of manganese nodules obtained from the East Siberian Sea. Semi-quantitative analysis was attempted for three main Mn-oxide minerals constituting the manganese nodules (i.e., todorokite, buserite and birnessite) using the peak area ratio of X-ray diffraction analysis graphs. In the East Siberian Sea manganese nodules, birnessite is more abundant than buserite or todorokite, and no correlation is found between the mineral composition and the internal texture. Instead a correlation is found between the relative content of todorokite and the lamellae depth. The todorokite content tends to increase from the surface to the core of the nodules, which can be attributed to a recrystallization process or difference in the growth rate within the nodule. This study shows that semi-quantitative analysis of manganese oxide minerals using the peak area ratio is useful in the mineralogical study of manganese nodules.

Solvothermal Preparation of Nanocrystalline TiO2 Using Alcohol-water Mixed Solvent (알코올-물 혼합용액을 이용하는 Solvothermal 법에 의한 나노크기의 TiO2 제조)

  • Lee, Sang Geun;Park, Seong Soo;Hong, Seong Soo;Park, Jong Myung;Lee, Seung Ho;Kim, Dae Sung;Lee, Gun Dae
    • Applied Chemistry for Engineering
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    • v.22 no.6
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    • pp.685-690
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    • 2011
  • In this study, a solvothermal reaction to prepare nanocrystalline titania was carried out using $TiCl_4$ and mixed solvents of alcohol and water. The effects of the type and the composition of alcohol on the crystal structure and agglomeration of final $TiO_2$ products were investigated. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscopy (SEM). In the solvothermal reaction using the n-butanol solutions with different volume ratios of n-butanol/water (100/0, 75/25, 50/50, 25/75, 0/100), the extent of agglomeration of obtained rutile $TiO_2$ was found to change with the volume ratio of n-butanol/water, and the n-butanol/water ratio of 75/25 revealed the best result for the preparation of well-dispersed nanocrystalline $TiO_2$ powders. The crystal phase of $TiO_2$ prepared through the solvothermal reaction changed with the type of alcohol in solvent (alcohol/water = 75/25). $TiO_2$ products obtained with the aqueous solutions of methanol, ethanol and isopropanol have an anatase phase, while that with n-butanol has a rutile phase. The results showed that, in the solvothermal reaction using both $TiCl_4$ as a starting material and the alcohol-water mixed solvents without any other additive, the enhancement of dispersion and control of crystal structure of $TiO_2$ products can be feasible by simply varying the composition and type of alcohol in the mixed solvents.

Crystallographic Study on the Selectivity and Distribution of Sr2+ Ions Within Zeolite A In the Presence of Competing Na+ Ions in Aqueous Exchange Solution (Na+ 경쟁이온이 존재하는 수용액에서 Zeolite A 내 Sr2+ 이온의 선택성 및 분포에 관한 결정학적 연구)

  • kim, Hu Sik;Park, Jong Sam;Lim, Woo Taik
    • Korean Journal of Mineralogy and Petrology
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    • v.35 no.1
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    • pp.41-50
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    • 2022
  • To study the properties of Sr2+ exchange into zeolite A with increasing the molar concentration of Na+ in given exchange solution, four single crystals of fully dehydrated Sr2+- and Na+- exchanged zeolite A were prepared by the bath method using mixed ion-exchange solutions. The Sr(NO3)2:NaNO3 molar rations of the ion exchange solution were 1:1(crystal 1), 1:100(crystal 2), 1:250(crystal 3), and 1:500 (crystal 4), respectively, with a total concentration of 0.05 M. The single-crystals were then vacuum dehydration at 623 K and 1×10-4 Pa for 2 days. Their single-crystal structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Pm3-m, at 100(1) K, and were then refined to the final error indices of R1/wR2=0.047/0.146, 0.048/0.142, 0.036/0.128, and 0.040/0.156 for crystals 1, 2, 3, and 4, respectively. In crystals 1 and 2, the 6 Sr2+ ions are found at three different crystallographic sites. In crystal 3, 1 Sr2+ and 10 Na+ ions are found in large cavity and sodalite unit. In crystal 4, only 12 Na+ ions occupy three equipoints. The degree of Sr2+ ion-exchange decreased sharply from 100 to 16.7 to 0% as the initial Na+ concentration increase and the Sr2+ concentration decrease. In addition, the unit cell constant of the zeolite framework decreased with this lower level of Sr2+ exchange.

Changes in the Linear Compressibility and Bulk Modulus of Natural Stilbite Under Pressure with Varying Pressure-Transmitting Media (천연 스틸바이트의 압력전달매개체에 따른 선형압축률 및 체적탄성률 비교 연구)

  • Hwang, Huijeong;Lee, Hyunseung;Lee, Soojin;Jung, Jaewoo;Lee, Yongmoon
    • Korean Journal of Mineralogy and Petrology
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    • v.35 no.3
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    • pp.367-376
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    • 2022
  • This study is a preliminary step to understand the reaction between various liquids and zeolite in the subduction zone environment. Stilbite, NaCa4(Al9Si27)O72·28(H2O), was selected and high pressure study was conducted on compressional behavior by the pressure-transmitting medium (PTM). Water and NaHCO3 solution that can exist in the subduction zone was used as PTM, and samples were pressurized from ambient to a maximum of 2.5 GPa. Below 1.0 GPa, both experiments show a low linear compressibility in the range of 0.001 to 0.004 GPa-1 and a high bulk modulus of 220(1) GPa. This is presumably because the structure of the stilbite becomes very dense due to insertion of water molecules or cations into the channel. On the other hand, at 1.0 GPa or higher, the trends of the two experiments are different. In the water run, the linear compressibility of the c-axis is increased to 0.006(1) GPa-1. In the NaHCO3 run, the linear compressibility of the b- and c-axis is increased to 0.006(1) GPa-1. The bulk modulus after 1.0 GPa shows values of 40(1) and 52(7) GPa in water and NaHCO3 run, respectively, confirming that stilbite becomes more compressible than that before 1.0 GPa. It is caused by the migration of cations and water molecules inside the channel, as the water molecules in the PTM start to freeze and stop to insert toward the channel at 1.0 GPa or more. In the NaHCO3 run, it is assumed that the distribution of extra-framework species inside the structure is changed by substitution of the Na+ cation. It can be expected from tendency of the relative intensity ratio of the (001) and (020) peaks which show a different from that of the water run.

Characteristics of Non-Spherical Manganese Nodule from the East Siberian Sea (동시베리아해 비구형 망가니즈단괴의 특성)

  • Koo, HyoJin;Park, MuSeong;Seo, ChoongMan;Cho, HyenGoo
    • Korean Journal of Mineralogy and Petrology
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    • v.34 no.4
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    • pp.241-253
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    • 2021
  • Manganese nodules have been found in the shallow water depth of the Arctic Ocean as well as in the abyssal plains of the Pacific and Indian Oceans, but detailed study for them were rarely investigated. Manganese nodules, collected from the East Siberian Sea through the Arctic Expedition using Araon ice braking vessel, have a high potential for Mn mineral resources because they have high Mn content with high Mn/Fe ratio. This study investigated the external form, size and weight, internal texture for the non-spherical manganese nodule, which has about 7 % of total nodule from the East Siberian Sea. This study also researched the relative Mn-oxide mineral composition using the peak area ratio of X-ray diffraction pattern and their chemical composition. All data obtained from non-spherical nodules were compared with the spherical ones. Ellipsoidal, platy and irregular types are common among 5 groups of non-spherical manganese nodule based on the external form, and major axis and weight have positive relationship. All non-spherical manganese nodules have core mainly composed of mud sediments. The average Mn oxide mineral contents in nodules are birnessite, buserite and todorokite in descending order. Although mineral composition does not show any correlation with the external form, kind of core or internal structure, todorokite and buserite contents tend to increase and birnessite content decrease from the surface to the core in the nodule. Non-spherical manganese nodules have higher Mn content and Mn/Fe ratio than those from the shallow water depth of the Arctic Sea and even in the deep-sea of the Pacific and Indian Ocean. Although non-spherical nodule is larger and heavier, and has lower Mn content and Mn/Fe ratio than spherical nodule, there are not any differences in mineral composition and internal structure between them. Almost all manganese nodules collected from the East Siberian Sea are attributed to diagenetic process, because they are higher than 5 in Mn/Fe ratio.

The Investigation and Conservation of Central Asia Wall Painting (No. 4074 and 4096) (중앙(中央) 아세아(亞細亞) 벽화(壁畵) 보존처리(保存處理)(I) - 벽화(壁畵)(본(本)4074, 본(本)4096)의 상웅조사(狀熊調査) -)

  • Kang, Hyung-tae;Yi, Yong-hee;Yu, Hei-sun;Kim, Yeon-mi;Jo, Yeon-tae;Aoki, Shigo;Yamamoto, Noriko;Ohbayashi, Kentaro
    • Conservation Science in Museum
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    • v.3
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    • pp.43-50
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    • 2001
  • This article is about a joint project carried out by the National Museum of Korea and the Tokyo Cultural Properties Research Institute for the conservation of central Asia Wall painting that has been selected for the exhibition at the new Seoul National Museum of Korea at Yongsan. The investigation of the wall painting revealed very useful information. This includes the condition of the object, and the identification of evident damage, such as cracks, loss of pigment, plus materials and methods employed during the object's creation, as well as previous conservation treatment. The object was mainly made by applying plaster to the body (wall) that consisted of a mixture of soils and rice straws. Then, on the surface of the wall-painting, pigments were used to draw and to colour it. As a part of the investigation, radiocarbon dating was conducted using straw samples taken from the object. The result indicates that the object is probably dated form between the end of the 10th Century and the beginning of the 13th Century. The result of X-ray diffraction also revealed the composition of the pigments used on the surface. These are 1. gypsom [Ca(SO4)·2H2O], CaSO4 and Calcite (CaCO3) and Calcite (CaCO3) that were used for the white background. 2. Pb3O4 and led Arsenate [Pb(As2O6) that were used for the red colouring. 3. Cuprite (Cu2O), Arsenolite (As2O3) and Arsenic Oxide (As2O4) that were used for the green colouring.

Non-Destructive Material Analysis of Whetstones Discovered in Grain Transport Ship of the Early Joseon Period (조선 초기 조운선(마도4호선)에서 출수된 숫돌의 비파괴 재질 분석 연구)

  • Dal-Yong Kong;Jae Hwan Kim;Eun Young Park;Yong Cheol Cho;Ki Hong Yang
    • Economic and Environmental Geology
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    • v.56 no.6
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    • pp.661-674
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    • 2023
  • From the seafloor of Taean, Chungcheongnamdo Province, a ship of the Joseon Dynasty was discovered for the first time in the history of underwater excavations in Korea in 2014 and was named Mado Shipwreck No. 4. A total of 27 unused whetstones loaded as tribute were discovered on the hull of Mado No. 4, which revealed that Mado Shipwreck No. 4 was a Grain transport ship that sank while carrying tribute from Naju to Hanyang between 1417 and 1425 (King Taejong to King Sejong). All of the 27 whetstones are in the shape of narrow and long sticks. The average values of length, width, thickness, and weight are 161.5 mm, 36.1 mm, 22.7 mm, and 253.2 g, respectively. The result of X-ray diffraction analysis shows that the constituent minerals are quartz, alkali feldspar, and plagioclase, which is similar to that of the high-resolution digital stereomicroscope analysis. The average porosity of Mado-2672 and 2673 is 2.69% and 1.78%, respectively, and the average surface hardness is 807.2HLD and 834.5HLD, respectively. It is interpreted that if the porosity increases beyond a certain level, it affects the decrease in surface hardness. All of these are made of feldspathic sandstones with an average SiO2 content of 74.51% and were confirmed to be suitable as grindstones. They are all medium whetstones when classified based on the SiO2 content. These whetstones are small in size and weight and are convenient to carry, so they are presumed to be a type of non-stationary whetstone, and are estimated to have been mainly used in the fields such as weapon polishing and craft production during the Joseon Dynasty.

Fabrication and characteristics of modified PZT System doped With $La_2O_3$ ($La_2O_3$가 첨가된 modified PZT계의 제조 및 특성)

  • 황학인;박준식;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.3
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    • pp.418-427
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    • 1997
  • The effect of $La_2O_3$ as a dopant on the microstructure structure, crystal structure and electrical properties was studied. $0.05Pb(Sn_{0.5}Sb_{0.5})O_3+0.11PbTiO_3+0.84PbZroO_3+0.4Wt%MnO_2$ (=0.05PSS +0.11PT+0.84PZ+0.4wt%$MnO_2$) systems doped with 0, 0.1, 0.3, 0.5, 0.7, 1, 3, 5 mole% $La_2O_3$ were fabricated and investigated sintering density, crystal structure and micro-structure. The sintered 0.05PSS+0.11PT+0.84PZ+0.4wt%$MnO_2$ system doped with $La_2O_3$showed sintering density of the range of 7.683 g/㎤ of 0 mole% doping to 7.815 g/㎤ of 0 mole% doping. The average grain sizes in the range of 0 to 5 mole% $La_2O_3$were decreased from 9.0 $\mu\textrm{m}$ to 1.3 $\mu\textrm{m}$. X-ray diffraction investigation of sintered bodies showed that solid solutions were formed between 0.05PSS+0.11PT+0.84PZ+0.4wt%$MnO_2$ system and $La_2O_3$ in the range of 0 to 1 mole% but second phases were formed in case of 3, 5 mole%. Dielectric constants at 1 kHz were increased with 0 to 3 mlole% $La_2O_3$ before and after poling at the condition of 5 $KV_{DC}$/mm at $120^{\circ}C$ or $140^{\circ}C$ during 20 minutes. All Dielectric losses at 1 kHz were less than 1%, Curie temperatures were $208^{\circ}C$, $183^{\circ}C$, $152^{\circ}C$ and $127^{\circ}C$ at 0, 0.5, 1, 3 mole% $La_2O_3$ respectively. The values of $K_p$ were increased from 0 to 3 mole% $La_2O_3$ after poling at condition of 5 $KV_{DC}$mm at the condition of $120^{\circ}C$ or $140^{\circ}C$. The case of 0.7 mole% $La_2O_3$doped 0.05PSS+0.11PT+0.84PZ+0.4wt%$MnO_2$ system showed $K_p$ of 14.5% by poling at $140^{\circ}C$ during 20 minutes.

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Temperature-Programmed Reduction of Copper Oxide Supported on ${\gamma}-Al_2O_3$ and $SiO_2$ (${\gamma}-Al_2O_3$$SiO_2$에 입혀진 산화 구리의 승온 환원)

  • Hwa-Gyung Lee;Chong-Soo Han;Min-Soo Cho;Kae-Soo Lee;Hakze Chon
    • Journal of the Korean Chemical Society
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    • v.30 no.5
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    • pp.415-422
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    • 1986
  • The metal-support interaction of copper oxide supported on ${\gamma}$-alumina and silica was studied by X-ray diffraction (XRD) and temperature-programmed reduction(TPR). It was found that XRD pattern of CuO can not be observed up to 5.0wt % copper content for CuO/${\gamma}-Al_2O_3$ while CuO/$SiO_2$ sample shows the CuO pattern even at 2.5wt% copper content. $H_2-$TPR of CuO/${\gamma}-Al_2O_3$ system shows four major peaks at 145${\circ}C$, 185${\circ}C$, 210${\circ}C$, and 250${\circ}C$. In the case of CuO/$SiO_2$, a large peak at 250${\circ}C$ was appeared accompanying a small peak at 425${\circ}C$. Comparing the TPR peaks with that of copper aluminate which was prepared from the calcination of CuO/${\gamma}-Al_2O_3$ at 1000${\circ}C$, the peaks at around 145${\circ}C$, 200${\circ}C$ (185${\circ}C$ and 210${\circ}C$), and 250${\circ}C$ were corresponded to $Cu^+$ ion in CuO interacting ${\gamma}-Al_2O_3$, $Cu^+$ ions in defect sites of ${\gamma}-Al_2O_3$ and $Cu^{2+}$ ion in the bulk CuO layer, respectively. From the results, it was concluded that there is considerable metal-support interaction in CuO on ${\gamma}-Al_2O_3$ and the interaction results in a stabilization of $Cu^+$ ion in the system.

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Heat Shield Property of Nanostructural-regulated Fe2O3/TiO2 Composites Filled with Polyacrylate Paint (나노구조 변화에 의한 Fe2O3/TiO2 복합재료를 충전한 Poly Acrylate 도료의 열차단 특성)

  • Kim, Dae Won;Ma, Young Kil;Kim, Jong Seok
    • Applied Chemistry for Engineering
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    • v.31 no.1
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    • pp.43-48
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    • 2020
  • Fe2O3 nanoparticles with the mixed structure of cubic and nanorod were synthesized by precipitation, hydrothermal, sol-gel method, etching process and heat treatment. Fe2O3/TiO2 core-shell (CS) of type Fe2O3@TiO2 composite was fabricated on a 20 nm nanolayer of TiO2 coated on the surface of Fe2O3 nanoparticles. Fe2O3/TiO2 yolk-shell (YS) composite was prepared by chemical etching and heat treatment of Fe2O3/TiO2 CS nanoparticles. Physical properties of Fe2O3, Fe2O3@TiO2 CS and Fe2O3@TiO2 YS nanoparticles were characterized by FE-SEM, HR-TEM and X-ray diffraction. The solar reflectance, commission internationale de l'Elcairage (CIE) color coordinate and heat shield temperatures of Fe2O3, CS and YS type Fe2O3@TiO2 pigments filled with poly acrylate (PA) paints were investigated by UV-Vis-NIR spectrometer and homemade heat shield temperature measuring device. The Fe2O3@TiO2 YS red pigment filled PA composite exhibited excellent near infrared light reflecting performance and also reduced the heat shield temperature of 13 ℃ than that of Fe2O3 filled counterparts.