• Bulletin of the Korean Chemical Society
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• 제13권4호
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• pp.425-428
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• 1992

Sodium substituted samples of $Y_{1-x}Na_xBa_2Cu_3O_{7-y}$ for $0.00{\leq}x{\leq}0.16$ were prepared and characterized by X-ray powder pattern, electrical resistivity and magnetic susceptibility measurements, Raman spectroscopy, and idometric titration. The Na substituted compounds have narrow solid solution limits where $0.00{\leq}x{\leq}0.16.$ As the Na concentration increases, the parent orthorhombic structure tends to gradually change to tetragonal. Small changes in the superconducting transition temperature, Tc, are observed in this solid solution region. Raman spectra for the Na phases are virtually identical with that of $YBa_2Cu_3O_7$ except that the Cu(1)-O(4) stretching mode at 504 $cm^{-1}$ and the Cu(2)-O(2,3) bending mode at 340 $cm^{-1}$ for x = 0.16 are slightly shifted. The hole concentrations of the sodium substituted compounds ranged from 0.31 to 0.33 per Cu site are increased with Na content. The substitution of $Na^+$ for $Y^{3+}$ site appears to create oxygen vacancies in the Cu-O chains, causes structural change from orthorhombic to tetragonal, and increases hole concentration in the substituted system.

• 자원환경지질
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• 제30권5호
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• pp.417-431
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• 1997

Characteristics of sedimentary rocks and enrichment of toxic elements in shale and coal from the Chungnam coal field were investigated based upon geochemistry of major, trace and rare earth elements. Shale and coal of the area are interbedded along the Traissic to the Jurassic Daedong Supergroup, which can be subdivided into grey shale, black shale and coal. The coal had been mined, however all the mines are abandonded due to the economic problems. The shale and coal are characterized by relatively low contents of $SiO_2$, and $Al_2O_3$ and high levels of loss-on-ignition (LOI), CaO and $Na_2O$ in comparison with the North American Shale Composite (NASC). Light rare earth elements (La, Ce, Yb and Lu) are highly enriched with the coal. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in shale and coal range from 30.0 to 351.8 and from 4.2 to 106.8, which have partly negative correlations against $SiO_2/Al_2O_3$ (1.24 to 6.06), respectively. Those are suggested that controls of mineral compositions in shale and coal can be due to substitution and migration of those elements by diagenesis and metamorphism. Shale and coal of the area may be deposited in terrestrial basin deduced from high C/S (39 to 895) and variable composition of organic carbon (0.39 to 18.40 wt.%) and low contents of reduced sulfur (0.01 to 0.05 wt.%). These shale and coal were originated from the high grade metamorphic and/or igneous rocks, and the rare earth elements of those rocks are slightly influenced with diagenesis and metamorphism on the basis of $Al_2O_3$ versus La, La against Ce, Zr versus Yb, the ratios of La/Ce (0.38 to 0.85) and Th/U (3.6 to 14.6). Characteristics of trace and rare earth elements as Co/Th (0.07 to 0.86), La/Sc (0.31 to 11.05), Se/Th (0.28 to 1.06), V/Ni (1.14 to 3.97), Cr/V (1.4 to 28.3), Ni/Co (2.12 to 8.00) and Zr/Hf (22.6~45.1) in the shale and coal argue for inefficient mixing of the simple source lithologies during sedimentation. These rocks also show much variation in $La_N/Yb_N$ (1.36 to 21.68), Th/Yb (3.5 to 20.0) and La/Th (0.31 to 7.89), and their origin is explained by derivation from a mixture of mainly acidic igneous and metamorphic rocks. Average concentrations in the shale and coal are As=7.2 and 7.5, Ba=913 and 974, Cr=500 and 145, Cu=20 and 26, Ni=38 and 35, Pb=30 and 36, and Zn=77 and 92 ppm, respectively, which are similar to those in the NASC. Average enrichment indices for major elements in the shale (0.79) and coal (0.77) are lower than those in the NASC. In addition, average enrichment index for rare earth elements in coal (2.39) is enriched rather than the shale (1.55). On the basis of the NASC, concentrations of minor and/or environmental toxic elements in the shale and coal were depleted of all the elements examined, excepting Cr, Pb, Rb and Th. Average enrichment indices of trace and/or potentially toxic elements (As, Cr, Cu, Ni, Pb, U and Zn) are 1.23 to 1.24 for shale and 1.06 to 1.22 for coal, respectively.

• 자원환경지질
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• 제39권6호
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• pp.675-687
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• 2006

이 연구에서는 청풍지역 하상퇴적물에 대한 지구화학적 특성 규명을 통해, 주성분원소 및 미량원소에 대한 청풍지역의 자연배경치를 제시하고, 지구화학적 재해에 대해 예견하고자 한다. 이를 위해 물이 흐르고 있는 1차 수계를 대상으로 하상퇴적물시료를 채취하였고, 실험실에서 자연건조 시켰으며, 화학적 분석을 위해 알루미나 몰타르를 이용하여 200메쉬 이하로 분쇄하였다. 주성분원소 및 미량성분원소는 XRD, XRF, ICP-AES, NAA를 이용하여 분석하였다. 청풍지역 하상퇴적물의 기반암에 따른 지질집단별 지구화학적 특성 비교를 위해, 화강암질편마암지역, 메타텍틱편마암지역, 다도응회암지역, 유치역암 지역, 능주용암지역으로 분류하였다. 청풍지역 하상퇴적물 전체에 대한 주성분원소 함량은 $SiO_2\;47.31{\sim}72.81\;wt.%,\;Al_2O_3 \;11.26{\sim}21.88\;wt.%,\;Fe_2O_3\;2.83{\sim}8.39\;wt.%,\;CaO\;0.34{\sim}7.54\;wt.%,\;MgO\; 0.55{\sim}3.59\;wt.%,\;K_2O\;1.71{\sim}4.31\;wt.%,\;Na_2O\;0.56{\sim}2.28\;wt.%,\;TiO_2\;0.46{\sim}1.24\;wt.%,\;MnO\;0.04{\sim}0.27\;wt.%,\;P_2O_5\;0.02{\sim}0.45\;wt.%$이다. 청풍지역 하상퇴적물 전체에 대한 미량성분원소 및 희토류원소 함량은 $Ba\;700ppm{\sim}8990ppm,\;Be\;1.0{\sim}3.50ppm,\;Cu\;6.20{\sim}60ppm,\;Nb\;12{\sim}28ppm,\;Ni\;4.4{\sim}61ppm,\;Pb\;13{\sim}34ppm,\;Sr\;65{\sim}787ppm,\;V\;4{\sim}98ppm,\;Zr\;32{\sim}164ppm,\;Li\;21{\sim}827ppm,\;Co\;3.68{\sim}65ppm,\;Cr\;16.7{\sim}409ppm,\;Cs\;72{\sim}37.1ppm,\;Hf\;4.99{\sim}49.2ppm,\;Rb\;71.9{\sim}649ppm,\;Sb\;0.16{\sim}5.03ppm,\;Sc\;4.97{\sim}5ppm,\;Zn\;26.3{\sim}375ppm,\;Ce\;60.6{\sim}373ppm,\;Eu\;0.82{\sim}6ppm,\;Yb\;0.71{\sim}10ppm$의 범위를 보였다.

• 자원환경지질
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• 제38권4호
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• pp.481-492
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• 2005

이 연구에서는 광주지역 하상퇴적물에 대한 지질집단별 지구화학적 특성에 대해 규명 하고자 한다. 이를 위해 물이 흐르고 있는 1차 수계를 대상으로 하상퇴적물시료 104개를 채취하였고, 실험실에서 자연건조 시켰다. 화학분석을 위한 시료는 알루미나 몰타르를 이용하여 200메쉬 이하로 분쇄하였고, XRF ICP-AES, NAA분석을 실시하였다. 연구지역 하상퇴적물에 대해, 지질집단별 지구화학적 특성 비교와 기존 암석에 대한 연구에서 얻어진 암석화학적인 특성과의 비교를 위해, 선캠브리아기 화강편마암 지역, 쥬라기 화강암 지역, 백악기 화순안산암 지역으로 분리하였다 광주지역 하상퇴적물의 주성분원소 함량은 $SiO_2\;51.89\~70.63\;wt.\%,\;Al_2O-3\;12.91\~21.95\;wt.\%,\;Fe_2O_3\;3.22\~9.89\;wt.\%,\;K_2O\;1.85\~4.49\;wt.\%,\;MgO\;0.68\~2.90\;wt.\%,\;Na_2O\;0.48\~2.34\;wt.\%,\;CaO\;0.42\~6.72\;wt.\%,\;TiO_2\;0.53\~l.32\;wt.\%,\;P_2O_5\;0.06~0.51\;wt.\%\;and\;MnO\;0.05\~0.69\;wt.\%.$이다. 하상퇴적물과 암석에 대한 AMF 삼각도에서, 암석은 칼크-알칼리계열에 도시되는데 비하여, 하상퇴적물은 솔레아이트 계열과 칼크-알칼리계열의 경계부위에 도시된다. 이는 $Fe_2O_3$ 함량이 암석에서보다 하상퇴적물에 더 많이 함유되어 있는 것과 관련이 있는 것으로 보인다. $SiO_2$에 대한 $K_2O+Na_2O$의 비교그림에서, 하상퇴적물은 암석에서와 같이 subalkaline 계열에 점시된다. 하상퇴적물의 미량성분원소 및 희토류 원소 함량은 $Ba 590\~2170ppm$, Be$1\~2.4$ppm, Cu $13\~179ppm$, Nb $20\~34ppm$, Ni$10\~50ppm$, Pb $17\~30$ppm, Sr $70\~1025$ ppm, V$42\~135$ ppm, Zr$45\~171$ ppm, Li$19\~77$ppm, Co$4.3\~19.3$ppm, Cr$28\~131$ppm, Cs$3.1\~17.6$ ppm, Hf $5\~27.6$ ppm, Rb $388\~202$ ppm, Sb$0.2\~l.2$ ppm, Sc$6.4\~17$ ppm, Zn $47\~389$ ppm, Pa $8.8\~68.8$ ppm, Ce$62\~272$ppm, Eu$1\~2.7$ppm and Yb$0.9\~6$ppm의 범위를 보인다.