• 한국재료학회지
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• 제12권8호
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• pp.595-599
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• 2002

A homogeneous and stable, amorphous-type, anorthite (CaO $Al_2$$O_3$ $2SiO_2$)powder was synthesized by an organic-inorganic steric entrapment route. Polyvinyl alcohol ( PVA) was used as an organic carrier for the precursor ceramic gel. The PVA content, its degree of polymerization and type of silica sol had a significant influence on the calcination and crystallization behavior of the precursors. For densifiction and crystallization at low temperature, porous and soft, amorphous-type anorthite powder was planetary milled for 20h. The milled powder crystallized to stable anorthite phase and densified to a relative density of 94% below $1000^{\circ}C$. In the development of crystalline phases of the planetary milled powder, omisteinbergite phase was unusually observed at $900^{\circ}C$, and then anorthite was observed at $950^{\circ}C$. The sintered anorthite had a thermal expansion coefficient of $4.6$\times$10^{-6}$ /$^{\circ}C$ and a dielectric constant of 7.5 at 1 MHz. Finally, the anorthite synthesized by the new process is expected to be an useful material for low-firing ceramic substrate.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.396.2-396.2
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• 2014

백색 유기발광소자는 전색 디스플레이, 조명으로서의 잠재적인 특성으로 차세대 디스플레이 소자 기술로 많은 주목을 받고 있다. 백색 유기발광소자는 주로 R-G-B 영역의 다양한 발광층을 적층하여 제작한다. 하지만 여러 발광층을 적층해야하기 때문에 제작할 때 공정 과정이 복잡해지고, 높은 생산단가를 가지게 된다. 이런 문제를 해결하기 위해 형광체를 이용한 백색 유기발광소자의 연구가 진행되고 있지만, 아직 색순도와 색좌표에 대한 많은 연구가 미흡한 상태이다. 본 연구에서는 무기물 형광체를 활용하여 백색 유기발광소자의 전기적 특성과 광학적 특성을 관찰하였고, 광원으로 사용된 청색 유기발광소자에 녹색과 적색의 무기물 형광체를 결합하는 방법으로 백색 유기발광소자를 제작하였다. 광원으로 사용한 청색 유기발광 소자는 투명전극으로 ITO를 사용하였고, 정공 수송층으로 N,N'-bis-(1-naphthyl)-N,N'-diphenylbenzidine, 발광층으로 4,4-bis(2,2-diphenylethen-1-yl)biphenyl, 정공 저지 층과 전자 수송 층은 각각 bathocuproine 과 4,7-diphenyl-1,10-phenanthroline 을 사용 하였다. 전자 주입 층으로는 lithium quinolate를 사용하였으며 음극으로는 Al을 사용하였다. 색 변환 층으로 사용된 유기물 형광체는 sol-gel 방법으로 제작된 녹색 형광체 Y3Al5O12:Ce, 적색 형광체 Ca2AiO19:Mn 을 사용하였다. Sol-gel 방법으로 제작된 형광체는 X선 회절 분석기를 통해 JCPDS cards를 확인하였고, 형광체의 녹색과 적색의 혼합비율에 따른 색좌표를 확인하여 백색 유기발광소자를 제작 하였다.

• 대한환경공학회지
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• 제36권12호
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• pp.843-850
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• 2014

본 연구는 국내 하수처리장에서 발생하는 감량화/안정화된 소각재를 무기바인더로 재이용하기 위하여 수행하였다. 실험은 무소성 공정으로 진행하였으며, Sewage Sludge Ash를 시멘트, Geobond 등의 바인더와 모래를 혼합하여 페이스트 시편과 몰탈 시편으로 성형하였다. 성형 후 양생과정을 거친 시편을 압축강도를 측정한 결과 KS 기준치 22.54 Mpa ($229.7kg/cm^2$)을 상회하고, 하수슬러지 소각재(SSA) 첨가율은 약 10~40%까지 가능한 것으로 나타나 개발하고자 한 하수슬러지 소각재를 무기바인더인 시멘트, Geobond의 대체 물질로 재활용이 가능함을 입증하였다.

• 한국광물학회지
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• 제9권1호
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• pp.26-34
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• 1996

The white leather-like playgorskite occurs as a vein in the Cretaceous sedimentary rocks in the Yeongsan area, Kyeongnam, Korea. It has been investigate by means of XRD, TEM, DTA-TG, IR and chemical analysis. The palygorskite vein is composed mostly of well-crystallized palygorskite. The wall rock of the vein is altered to smectite along both sides of the vein. According to TEM observation the palygorskite shows a fibrous habit. The sizes offibers are quite variable, ranging from 0.1 to 3.0 micron in length. From XRD data, the palygorskite has orthorhombic unit cell with a=12.726$\AA$, b=17.796$\AA$, c=5.1666$\AA$. The chemical formula of the palygorskite was calculated as [Si7.93Al0.07](Al1.91Fe+30.11Mg1.96)Ca0.01O20(OH)4(OH2)2.

• 한국세라믹학회지
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• 제18권3호
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• pp.171-181
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• 1981

Alkaline-earth porcelains have been prepared from mixture of kaolin, quartz, and synthetic calcines obtained by calcining a mixture of kaolin and more than two different kinds of alkaline-earth carbonates. They were magnesium, calcium and barium carbonates which are inexpensive and readily available. The vitrification behavior of the batch mixes was investigated in the firing range of 1240$^{\circ}$to 1380$^{\circ}$, in relation to the body compositions. It appeared that the density and the firing temperature depended largely on the content of alkaline-earth oxides in the body. These porcelains posses excellant dielectric properties, and are especially valuable as bases for deposited carbon resistors for which they were developed. An illustrative composition is 50% Dong Hwa kaolin, 22.4% Chang Shin quartz, 27.6% calcine. The composition of the calcine is 70% Dong Hwa kaolin, 10.7% BaCO3, 13.5% CaCO3, 5.8% MgCO3. The specific resistance of this body is $1.2{\times}10^{15}$ ohm-cm at 5$0^{\circ}C$, $2.5{\times}10^{14}$ ohm-cm 10$0^{\circ}C$, $2.5{\times}10^{13}$ ohm-cm at 15$0^{\circ}C$, $1.8{\times}10^{12}$ohm-cm at 20$0^{\circ}C$.

• 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.

• 한국건설순환자원학회논문집
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• 제1권2호
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• pp.101-106
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• 2013

본 연구에서는 CA계 슬래그와 무수석고를 사용하여 수축저감제를 제조하였으며, 모르타르의 압축강도와 건조수축 특성을 향상시키기 위해서 상기 수축저감제를 첨가하였다. 모르타르의 응결시간, 길이변화율 및 압축강도는 수축저감제의 배합비율에 따라 변화하였다. 슬래그가 0~7%까지 첨가된 모르타르는 슬래그 첨가량 증가에 따라 응결시간이 짧아졌으며, 7일까지의 길이변화율은 유사하였다. 7일 양생조건의 압축강도는 $C_{12}A_7$계 슬래그 첨가량 증가에 따라 증가되었다. $C_{12}A_7$계 슬래그가 6% 첨가된 모르타르의 28일 강도는 약 36 MPa이었으며, 35일에서의 건조수축율은 가장 낮은 값을 나타내었다. 그러므로 $C_{12}A_7$계 슬래그가 6% 첨가된 모르타르에서 우수한 물리적 특성을 발현하는 것으로 판단할 수 있었다.

• 한국광물학회지
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• 제9권2호
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• pp.55-63
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• 1996

Epidote occurs as veinlets in the propylitic alteration zone of the Bobae clay deposit, Pusan, Korea. Its cell parameters apparently decrease with the contents of Al, Fe, and Ca. Fourier transform infrared (FTIR) spectra show one hydrosyl environment related to AlM2 at 3357-3358 cm-1. In the mid-infrared region, the peaks at 950 and 1030 cm-1 sharper with increasing Al shifting to higher energy region. The peak at 885 cm-1 shifts slightly to a lower energy region with a decreasing intensity as the Fe content increases. In the far-IR region, epidote exhibits absorption bands at 120 and 140 cm-1, which are related to the Ca-O bonds in A-sites.M ssbauer spectra of epidote show that the isomer shifts of Fe3+ range from 0.36-0.37 at the M3 site and from 0.35-0.44 at M1 site. Fe2+ shows the isomer shift ranging from 1.11 to 1.13. Quadrupole splitting is 2.04 for Fe3+M3, 0.52-0.70 for Fe3+M1, and 2.61-2.70 for Fe2+M3. Calculation shows Fe3+M386-90.7%, Fe3+M12.5-3.6%, and Fe2+M35.8-11.4% of total iron, showing preferential distribution of Fe3+ in the M3 site. The Fe3+M3 content is between 0.486 and 0.513 per formula unit. in the Fe-rich epidote, less Fe3+ and more Fe2+ are accommodated in the M1 and M3 sites. Hence, the overall disorder increases as total Fe content increase. The ordering parameter of the Bobae epidote is 0.93-0.95, suggesting a disequilibrium state below 200$^{\circ}C$. The constant temperature over a long period may be essential for the transition from disordered state to equilibrium state, despite the possible variation in flux and composition of the hydrothermal fluid.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1090-1096
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• 2005

$Ag_4Br_4$ nanoclusters have been synthesized in about 75% of the sodalite cavities of fully $K^+$-exchanged zeolite A (LTA). An additional KBr molecule is retained in each large cavity as part of a near square-planar $K_4Br^{3+}$ cation. A single crystal of $Ag_{12}$-A, prepared by the dynamic ion-exchange of $Na_{12}$-A with aqueous 0.05 M $AgNO_3$ and washed with $CH_3OH$, was placed in a stream of flowing 0.05 M KBr in $CH_3OH$ for two days. The crystal structure of the product ($K_9(K_4Br)Si_{12}Al_{12}O_{48}{\cdot}0.75Ag_4Br_4$, a = 12.186(1) $\AA$) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm m. It was refined with all measured reflections to the final error index $R_1$ = 0.080 for the 99 reflections for which $F_o\;{\gt}\;4_{\sigma}\;(F_o)$. The thirteen $K^+$ ions per unit cell are found at three crystallographically distinct positions: eight $K^+$ ions in the large cavity fill the six-ring site, three $K^+$ ions fill the eight-rings, and two $K^+$ ions are opposite four-rings in the large cavity. One bromide ion per unit cell lies opposite a four-ring in the large cavity, held there by two eight-ring and two six-ring $K^+$ ions ($K_4Br^{3+}$). Three $Ag^+$ and three $Br^-$ions per unit cell are found on 3-fold axes in the sodalite unit, indicating the formation of nano-sized $Ag_4Br_4$ clusters (interpenetrating tetrahedra; symmetry $T_d$; diameter ca. 7.9 $\AA$) in 75% of the sodalite units. Each cluster (Ag-Br = 2.93(3) $\AA$) is held in place by the coordination of its four $Ag^+$ ions to the zeolite framework (each $Ag^+$ cation is 2.52(3) $\AA$ from three six-ring oxygens) and by the coordination of its four $Br^-$ ions to $K^+$ ions through six-rings (Br-K = 3.00(4) $\AA$).

• 자원환경지질
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• 제46권2호
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• pp.179-198
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• 2013

신장 위구르 자치구 바이청현 보즈구얼 지역의 A형 화강암체는 타림지대의 북쪽 끝과 동서쪽 방향의 알칼리 관입암대에 접하여 위치해 있다. 이 화강암체는 추휘석(aegrine)이나 아페소나이트(arfvedsonite)-석영-알칼리장석 섬장암, 또는 아페소나이트-알칼리장석 화강암, 흑운모-알칼리장석 섬장암으로 구성되며, 주요광물로는 알바이트(albite), K-장석, 석영, 아페소나이트(arfvedsonite), 추휘석, 시데로필라이트(siderophyllite) 등이 있으며 부성분 광물로는 지르콘(zircon), 파이로클로르(pyrochlore), 토라이트(thorite), 형석, 모나자이트(monazite), 바스네사이트(bastnaesite), 제노타임(xenotime), 아스트로필라이트(astrophyllite) 등이 있다. 이 알칼리 화강암체는 67.32%의 평균값을 갖는 $SiO_2$를 포함하고 평균 11.14%의 높은 $Na_2O+K_2O$(9.85~11.87%) 조성을 보이며 이 중 $K_2O$는 평균 4.73%의 조성을 보인다. $K_2O/Na_2O$의 비는 0.31~0.96 사이이며 $Al_2O_3$는12.58%부터 15.44%사이로 포함되고 총 $FeO^T$함량은 2.35~5.65%이내이다. CaO, MgO, MnO, $TiO_2$의 함량은 낮은 것으로 관찰된다. 희토류원소의 총량은 평균 $77{\times}10^{-6}$으로 비교적 높게 나타나고 경희토원소는 농축되어 있지만 중희토원소는 Eu원소의 부(-)의 이상과 함께 상대적으로 결핍되는 특징을 가진다. 또한 알칼리 화강암체의 chondrite-normalized 희토류원소의 패턴은 오른쪽으로 기울어진 갈매기형태를 보인다. Zr는 평균 $594{\times}10^{-6}$의 함량을 보이며 Zr+Nb+Ce+Y는 평균 $1362{\times}10^{-6}$의 함량을 나타낸다. 또한 이 알칼리 화강암체는 높은 HFSE(Ga, Nb, Ta, Zr, Hf)함량과 낮은 LILE(Ba, K, Sr)함량을 보인다. Nb/Ta의 비는 평균 16.5이며 Zr/Hf의 비는 평균 36.80이다. 지르콘은 경희토원소에서 결핍되고 중희토원소에서 농축되어있다. 지르콘의 chondrite-normalized 희토류원소는 Eu원소의 강한 부(-)의 이상과 함께 왼쪽으로 기울어진 갈매기형태를 보인다. 보즈구얼지역의 A타입 화강암체는 A1타입의 화강암과 유사한 특징을 나타낸다. 화강암질 마그마의 평균온도는 $832{\sim}839^{\circ}C$이며 보즈구얼 지역의 A타입 화강암체는 지각과 맨틀의 혼합양상을 보이며 고온, 무수, 낮은 산소의 퓨개시티(fugacity) 환경을 가진 판 내부의 비조산대에서 생성되었을 가능성이 있다.