• 제목/요약/키워드: Ni-Substitution

검색결과 145건 처리시간 0.032초

충남탄전, 대동누층군의 셰일과 탄질암에 관한 암석화학 및 환경지구화학적 특성 (Petrochemistry and Environmental Geochemistry of Shale and Coal from the Daedong Supergroup, Chungnam Coal Field, Korea)

  • 이찬희;이현구;김경웅
    • 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.

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중국 Xiquegou 연-아연 광상의 돌로마이트와 녹니석 산상과 화학조성 (Occurrence and Chemical Composition of Dolomite and Chlorite from Xiquegou Pb-Zn Deposit, China)

  • 유봉철
    • 광물과 암석
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    • 제35권2호
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    • pp.125-140
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    • 2022
  • Xiquegou 연-아연 광상은 중국 동북지역에선 가장 규모가 큰 연-아연 광화대 중의 하나인 Qingchengzi orefield에 위치한다. 이 광상의 주변지질은 시생대의 그래뉼라이트(granulite)와 이를 관입한 고원생대의 미그마타이트질 화강암과 고-중원생대의 소딕(sodic) 화강암을 부정합으로 피복한 고원생대의 Liaohe 층군 및 이들을 관입한 중생대의 섬록암과 몬조나이틱 화강암으로 구성된다. 이 광상은 고원생대의 Liaohe 층군내 Dashiqiao 층의 unit 3(돌로마이트질 대리암과 편암)내에 발달된 단층대를 따라 산출되는 맥상 광체로 트라이아스기의 마그마-열수형 광상에 해당된다. Xiquegou 연-아연 광상에서 석영, 인회석, 방해석, 황철석, 유비철석, 자류철석, 백철석, 섬아연석, 황동석, 황석석, 방연석, 사면동석, 에렉트럼, 휘은석, 자연은 및 농홍은석 등이 산출되며 모암변질로는 규화작용, 황철석화작용, 돌로마이트화작용, 녹니석화작용 및 견운모화작용 등이 관찰된다. 이 광상의 산출 광물조합 및 정출순서를 기초로, 돌로마이트는 1)모암인 돌로마이트(D0) 및 2)연-아연 광화작용에 따른 모암변질 산물인 돌로마이트(D1)로 두 유형이 확인된다. 이들 돌로마이트의 화학조성은 각각 Ca1.03-1.01Mg0.95-0.83 Fe0.12-0.02Mn0.02-0.00(CO3)2(D0) 및 Ca1.16-1.00Mg0.79-0.44Fe0.53-0.13Mn0.03-0.00As0.01-0.00(CO3)2(D1)로써 이론적인 돌로마이트의 화학조성보다 미량원소들의 함량이 높다. 특히, FeO, PbO, Sb2O5 및 As2O5 원소들은 모암변질 산물인 돌로마이트(D1)에서 높은 함량을 갖는다. 또한 이 광상의 모암에서 산출되는 돌로마이트(D0)는 Ferroan 돌로마이트에 해당되며 모암변질 산물인 돌로마이트(D1)는 철백운석 및 Ferroan 돌로마이트에 해당된다. 모암변질 산물인 녹니석의 화학조성은 (Mg1.65-1.08Fe2.94-2.50Mn0.01-0.00Zn0.01-0.00Ni0.01-0.00Cr0.02-0.00V0.01-0.00Hf0.01-0.00Pb0.01-0.00Cu0.01-0.00As0.03-0.00Ca0.02-0.01Al1.68-1.61)5.77-5.73(Si2.84-2.76Al1.24-1.16)4.00O10(OH)8로써 이론적인 녹니석과 유사하며 Fe-rich 녹니석에 해당된다. 또한 이 녹니석의 화학조성 변화는 주로 팔면체적 Fe2+ <-> Mg2+ (Mn2+) 치환과 일부 팬자이틱 또는 Tschermark 치환(Al3+,VI+Al3+,IV <-> (Fe2+ 또는 Mg2+)VI+(Si4+)IV)메카니즘에 의해 일어났음을 알 수 있다.

병원의 미래 현금흐름 정보예측 (A Study on the Predictability of Hospital's Future Cash Flow Information)

  • 문영전;양동현
    • 한국병원경영학회지
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    • 제11권3호
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    • pp.19-41
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    • 2006
  • The Objective of this study was to design the model which predict the future cash flow of hospitals and on the basis of designed model to support sound hospital management by the prediction of future cash flow. The five cash flow measurement variables discussed in financial accrual part were used as variables and these variables were defined as NI, NIDPR, CFO, CFAI, CC. To measure the cash flow B/S related variables, P/L related variables and financial ratio related variables were utilized in this study. To measure cash flow models were designed and to estimate the prediction ability of five cash flow models, the martingale model and the market model were utilized. To estimate relative prediction outcome of cash flow prediction model and simple market model, MAE and MER were used to compare and analyze relative prediction ability of the cash flow model and the market model and to prove superiority of the model of the cash flow prediction model, 32 Regional Public Hospital's cross-section data and 4 year time series data were combined and pooled cross-sectional time series regression model was used for GLS-analysis. To analyze this data, Firstly, each cash flow prediction model, martingale model and market model were made and MAE and MER were estimated. Secondly difference-test was conducted to find the difference between MAE and MER of cash flow prediction model. Thirdly after ranking by size the prediction of cash flow model, martingale model and market model, Friedman-test was evaluated to find prediction ability. The results of this study were as follows: when t-test was conducted to find prediction ability among each model, the error of prediction of cash flow model was smaller than that of martingale and market model, and the difference of prediction error cash flow was significant, so cash flow model was analyzed as excellent compare with other models. This research results can be considered conductive in that present the suitable prediction model of future cash flow to the hospital. This research can provide valuable information in policy-making of hospital's policy decision. This research provide effects as follows; (1) the research is useful to estimate the benefit of hospital, solvency and capital supply ability for substitution of fixed equipment. (2) the research is useful to estimate hospital's liqudity, solvency and financial ability. (3) the research is useful to estimate evaluation ability in hospital management. Furthermore, the research should be continued by sampling all hospitals and constructed advanced cash flow model in dimension, established type and continued by studying unified model which is related each cash flow model.

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Thermoplasma acidophilum 유래 ${\alpha}$-glucosidase로 부터 생산된 glycosynthase 돌연변이 단백질의 개선된 당전이 효율 (Improvement of Transglycosylation Efficiency using a Glycosynthase Mutant derived from Thermoplasma acidophilum ${\alpha}$-Glucosidase)

  • 황성민;서성화;박인명;최경화;김도만;차재호
    • 한국미생물·생명공학회지
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    • 제40권2호
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    • pp.104-110
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    • 2012
  • Glycosynthase는 친핵성 아미노산을 비친핵성 아미노산으로 치환하여 당전이 산물의 가수분해를 막아서 당전이 효율을 증가시킬 수 있다. 이전 연구에서 본 실험실은 열에 안정하고 산에 강한 Thermoplasma acidophilum 유래의 ${alpha}$-glucosidase (AglA)가 당전이 활성이 있음을 입증하였으나 시간이 지남에 따라 당전이 산물이 가수분해 되었다. 이러한 AglA의 당전이 효율을 개선하기 위하여 친핵성 아미노산인 아스파라긴산을 글리신으로 치환하였다. 이 치환된 glycosynthase는 니켈 친화력 크로마토그래피를 통하여 정제되었으며, 정제된 돌연변이 단백질의 배당체를 합성하는 능력이 말토오스를 공여체로 그리고 p-nitrophenyl-${alpha}$-D-glucopyranoside($pNP{\alpha}G$)를 수용체로, 그리고 $pNP{\alpha}G$가 당공여체 및 수용체로 이용될 수 있는지 검사하였다. Glycosynthase를 이용한 당전이 산물의 수율은 약 42.5%를 보였으며 시간이 지남에 따라서 가수분해되지 않았다. 박막 크로마토그래피법을 이용한 반응산물의 분석은 수용체의 높은 농도에서 기존의 효소보다 많은 양의 배당체를 합성할 수 있음을 보여주었고, 특히 중성보다 낮은 pH 영역에서 가장 높은 활성을 보여줌을 확인하였다. 이러한 결과는 glycosynthase가 산업적으로 배당체를 합성하는데 유용성이 크다는 것을 나타낸다.

Preparation of AgCl/Ag3PO4/Diatomite Composite by Microemulsion Method for Rapid Photo-Degradation of Rhodamine B with Stability under Visible Light

  • Zhu, Hai-Tao;Ren, Qi-Fang;Jin, Zhen;Ding, Yi;Liu, Xin-Yu;Ni, Xi-Hui;Han, Meng-Li;Ma, Shi-Yu;Ye, Qing;Oh, Won-Chun
    • 한국재료학회지
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    • 제30권8호
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    • pp.383-392
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    • 2020
  • In this paper, AgCl/Ag3PO4/diatomite photocatalyst is successfully synthesized by microemulsion method and anion in situ substitution method. X-ray diffraction (XRD), photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) are used to study the structural and physicochemical characteristics of the AgCl/Ag3PO4/diatomite composite. Using rhodamine B (RhB) as a simulated pollutant, the photocatalytic activity and stability of the AgCl/Ag3PO4/diatomite composite under visible light are evaluated. In the AgCl/Ag3PO4/diatomite visible light system, RhB is nearly 100 % degraded within 15 minutes. And, after five cycles of operation, the photocatalytic activity of AgCl/Ag3PO4/diatomite remains at 95 % of the original level, much higher than that of pure Ag3PO4 (40 %). In addition, the mechanism of enhanced catalytic performance is discussed. The high photocatalytic performance of AgCl/Ag3PO4/diatomite composites can be attributed to the synergistic effect of Ag3PO4, diatomite and AgCl nanoparticles. Free radical trapping experiments are used to show that holes and oxygen are the main active species. This material can quickly react with dye molecules adsorbed on the surface of diatomite to degrade RhB dye to CO2 and H2O. Even more remarkably, AgCl/Ag3PO4/diatomite can maintain above 95 % photo-degradation activity after five cycles.