• 한국토양비료학회지
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• 제16권4호
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• pp.333-342
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• 1983

1. 식물체(植物體) 중(中) 전생육기간(全生育期間)동안 검출(檢出)된 지방산(脂肪酸)의 종류(種類)는 $C_{12:0}$, $C_{14:0}$, $C_{16:0}$, $C_{16:1}$, $C_{16:2}$, $C_{18:0}$, $C_{18:1}$, $C_{18:2}$, $C_{18:3}$, $C_{20:2}$와 몇종(種)의 미동정(未同定)된 지방산(脂肪酸)으로 구성(構成)되어 있었다. 2. 규산흡수양(珪酸吸收量), 건물중(乾物重) 및 수량(收量)은 unsaturated fatty acid/saturated fatty acid와 최고분얼기(最高分蘖期) 및 출수기(出穗期)에는 유의적(有意的)인 정(正)(+)의 상관(相關)이 있었으며 수확기(收穫期)에는 유의적(有意的)인 상관(相關)은 없었으나 전반적(全般的)으로 역(逆)(-)의 관계(關係)가 있었다. 3. 식물체중(植物體中) UFA/SFA 비(比)의 평균치(平均値)는 최고분얼기(最高分蘖期) 및 출수기(出穗期)에서는 토양중(土壤中) 규산함량(珪酸含量)이 180ppm까지는 규산함량(珪酸含量)이 높을수록 증가(增加)하였고, 규산자원(珪酸資源) 200kg/10a 시비구(施肥區)(약(約) 410ppm)에서는 감소(減少)하였다. 4. 최고분얼기(最高分蘖期)의 sitosterol/stigmasterol 비(比)는 토양중(土壤中) 규산농도(珪酸濃度)가 높을수록 계속 증가(增加하였으나, 출수기(出穗期)에 있어서는 그 비(比)가 토양중(土壤中) 규산농도(珪酸濃度)를 180ppm 조절시(調節時)까지는 증가(增加)하다가 200kg/10a 시용(施用)(410ppm)에서는 감소(減少)하였다.

• Macromolecular Research
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• 제17권10호
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• pp.776-784
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• 2009

N,N-dimethyldodecylamine (tertiary amine)-modified MMT (DDA-MMT) was prepared as an organically modified layered silicate (OLS), after which styrene-butadiene rubber (SBR) nanocomposites reinforced with the OLS were manufactured via the latex method. The layer distance of the OLS and the morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). By increasing the amount of N,N-dimethyldodecylamine (DDA) up to 2.5 g, the maximum values of torque, tensile strength and wear resistance of the SBR nanocomposites were increased due to the increased dispersion of the silicate layers in the rubber matrix and the increased crosslinking of the SBR nanocomposites by DDA itself. When SBR nanocomposites were manufactured by using the ternary filler system (carbon black/silica/OLS) to improve their dynamic properties as a tire tread compound, the tan $\delta$(at $0^{\circ}C$ and $60^{\circ}C$) property of the compounds was improved by using metal stearates instead of stearic acid. The mechanical properties and wear resistance were increased by direct substitution of calcium stearate for stearic acid because the filler-rubber interaction was increased by the strong ionic effect between the calcium cation and silicates with anionic surface. However, as the amount of calcium stearate was further increased above 0.5 phr, the mechanical properties and wear resistance were degraded due to the lubrication effect of the excessive amount of calcium stearate. Consequently, the SBR/organoclay nanocomposites that used carbon black, silica, and organoclay as their ternary filler system showed excellent dynamic properties, mechanical properties and wear resistance as a tire tread compound for passenger cars when 0.5 phr of calcium stearate was substituted for the conventionally used stearic acid.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.292-295
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• 2004

Recently, polymer-clay hybrid materials have received considerable attention from both a fundamental research and application point of view. This organ-inorganic hybrid, which contains a nanoscale dispersion of the layered silicates, is a material with greatly improved thermal and mechanical characteristics. Two classes of nanocomposites were synthesized using an unsaturated polyester resin as the matrix and sodium montmorillonite as well as an organically modified montmorillonite as the reinforcing agents. X -ray diffraction pattern of the composites showed that the interlayer spacing of the modified montmorillonite were exfoliated in polymer matrix. The mechanical properties also supported these findings, since in general, tensile strength, modulus with modified montmorillonite were higher than the corresponding properties of the composites with unmodified montmorillonite. Adding organically modified clay improved the tensile strength of unsaturated polyester by $22\%$ and the tensile modulus of unsaturated polyester was also improved by $34\%$.

• Corrosion Science and Technology
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• 제7권4호
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• pp.212-218
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• 2008

Inorganic ion exchange compounds (IECs) including hydrotalcites and bentonite clays are a well known classes of layered mixed metal hydroxides or silicates that demonstrate ion exchange properties. These compounds have a range of applications from water purification to catalyst supports. The use of synthetic versions of these compounds as environmentally friendly additives to paints for storage and release of inhibitors is a new and emerging application. In this paper, the general concept of storage and release of inhibiting ions from IEC-based particulate pigments added to organic coatings is presented. The unique aspects of the IEC structure and the ion exchange phenomenon that form the basis of the storage and release characteristic are illustrated in two examples comprising an anion exchanging hydrotalcite compound and a cation exchanging bentonite compound. Examples of the levels of corrosion protection imparted by use of these types of pigments in organic coatings applied to aluminum alloy substrates is shown. How corrosion inhibition translates to corrosion protection during accelerated exposure testing by organic coatings containing these compounds is also presented.

• 한국분말재료학회지
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• 제12권2호
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• pp.122-130
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• 2005

Layered silicate was synthesized at hydrothermal condition from silica adding to various materials. Nano-clay was synthesized by intercaltion of various amine compounds into synthetic layered silicate. The products were analysed by XRD, SEM, and FT-IR in order to examine the condition of synthesis and intercalation. From the results, it was confirmed that kaolinite was synthesized from precipitated silica and gibbsite at $220^{\circ}C$ during 10 days, and hetorite was synthesized from silica sol at $100^{\circ}C$ during 48 h. Na-Magadiite was synthesized from silica gel at $150^{\circ}C$ during 72 h, and Na-kenyaite was synthesized from silica gel at $160^{\circ}C$ during 84 h. Nano-clay was prepared using synthetic layered silicate intercalated with various amine compounds. Kenyaite was easily intercalated by various organic compounds, and has the highest basal-spacing value among other layered silicates. Basal-spacing was changed according to the length of alkyl chain of amine comopounds. Polymer can be easily intercalated by dispersion with large space of interlayer. Finally, epoxy/nano-clay nanocomposite can be easily prepared.

• 한국작물학회지
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• 제42권6호
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• pp.800-804
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• 1997

규산시용 유무에 따라 생산된 미질을 평가하기 위하여 평택통 미사질양토(배수가 약간 불량한 보통답) 조건인 영남농업시험장 동일비료 장기 연용 시험구(29년차)의 비료 3요소구, 3요소＋규산시용구, 3요소＋퇴비시용구에서 1995년도 생산된 화남벼의 미립에 대한 등숙색택, 미립의 외관 및 미질 관련 특성을 분석 한 결과를 요약하면 다음과 같다. 1. 규산시용구에서는 정조의 백도치가 높고 선황색으로 색도가 높아 등숙색택이 좋아졌으며 반점립과 그을름립비율이 낮아졌다. 2. 규산시용으로 현미 중 피해립, 청미 및 변색립율이 떨어져 완전미율이 6.1∼7.5％ 증가되었고 백미 중 완전미율도 1.8∼3.5％ 증가되었으며 심ㆍ복백미율도 낮았다. 3. 규산시용으로 아밀로스 함량, 단백질 함량 및 요드정색도는 낮아졌고 아밀로그램의 최고점도, Breakdown및 식미품질분석계에 의한 식미치는 높아져서 식미를 향상시키는 요인으로 작용되었다.

• 공업화학
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• 제10권4호
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• pp.568-575
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• 1999

백금족 금소과 규산염을 포함하는 자동차 폐촉매 내의 백금족 금속과 주요 성분들을 ICP-AES로 동시에 분석하기 위한 두 종류의 전처리 방법이 비교되었다. HF, $HNO_3$, HCl, $HClO_4$, $H_2O_2$, 및 $H_3BO_3$ 등의 혼합산의 다양한 조합을 사용하여 열판(hot plate) 용해법과 밀폐용기를 사용하는 극초단파(microwave) 가압-가열법을 비교 검토하였다. 전통적인 열판 용해법보다 밀폐용기를 사용한 극초단파 가압-가열법이 화수율, 분석시간 및 사용하는 양 등의 측면에서 상대적으로 우수한 결과를 나타내었고, 0.25 g의 폐촉매 시료에 대하여 HF 2 mL, $HNO_3$2 mL, 그리고 HCl 6 mL를 사용하여 200 psi(13.79 bar), $180^{\circ}C$ 조건에서 1시간 동안 가열한 후, 5% (w/v) $H_3BO_3$ 16 mL를 사용하여 20 psi(1.38 bar), $100^{\circ}C$ 조건에서 10분간 가열한 다음, 왕수 10 mL로 열판에서 두 번 반복하여 처리하는 것이 백금족 금속의 회수율 측면에서 가장 좋은 결과를 가져왔고(XRF 분석 대비 85~110%), 이 방법은 2% 이내의 상대 표준 편차를 보임으로써, 자동차 폐촉매의 일상적인 분석기법으로서의 충분한 가능성을 보였다.

• 광물과 암석
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• 제34권2호
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• pp.121-131
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• 2021

마그네슘(magnesium; Mg)은 탄산염 광물이 침전된 과거의 환경 조건을 유추하기 위한 지화학 지시자로 활용되어오고 있다. Mg를 신뢰도 높은 지화학 지시자로 활용하기 위해서는 Mg의 화학종을 근거로 한 Mg의 광물 함유 기작이 반드시 규명되어야만 하며, 관련 실험 연구들은 주로 고해상도(high resolution)의 방사광가속기(synchrotron) X-선 흡수 분광(X-ray absorption spectroscopy; XAS) 기법을 통해 Mg의 화학종을 유추한다. 그러나, Mg가 미량 함유된 광물의 XAS 스펙트럼 해석의 높은 불확실성 때문에 화학종 유추가 어려운 경우가 많다. 양자역학 밀도범함수이론(density functional theory; DFT)은 결정구조에 대한 흡수 스펙트럼을 예측할 수 있기 때문에, XAS 스펙트럼 해석의 불확실성을 줄일 수 있다. 이번 논문에서는 DFT 기반의 제일원리 내각 준위 분광법(ab initio core-level spectroscopy method)을 통해 Mg 규산염 및 (수)산화광물에 대한 Mg K-edge 흡수 스펙트럼을 계산하여 Mg의 배위 결합 환경을 나타내는 구조 인자와의 상관관계를 분석하였다. 계산 결과, DFT 계산으로 얻은 Mg 규산염 및 (수)산화물의 이론 Mg K-edge 흡수 스펙트럼은 기존 XAS 실험으로 얻어진 스펙트럼의 주요 형태를 상당 부분 재현해낼 수 있었다. 계산으로 얻은 광물의 제일원리 Mg K-edge 흡수 스펙트럼의 흡수-끝(absorption edge)과 평균 Mg-O 결합거리 및 Mg 유효배위수를 비교 분석한 결과, 약한 양의 상관관계를 보여주었다. 이번 연구 결과는 DFT 계산이 다양한 광물 내 Mg의 화학종에 대한 표준 스펙트럼 세트를 제공할 수 있는 강력한 도구임을 보여주며, 추후 탄산염 광물에 함유된 정확한 Mg의 화학종을 동정하는데 DFT 계산이 큰 역할을 할 수 있음을 제시한다.

• 한국전기전자재료학회논문지
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• 제28권5호
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• pp.295-299
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• 2015

In this paper to improve the ionic conduction properties, lanthanum silicate apatite $La_{9.33}(SiO_4)_6O_2$ ceramic, which substituted by V ions at Si-site, were fabricated by the mixed-oxide method. And we investigated the structural and electrical properties of $La_{9.33}(Si_{6-x}V_x)O_{26}$ specimens with variation of dopants for the application of solid oxide fuel cells. The sintering temperature of $La_{9.33}(Si_{6-x}V_x)O_{26}$ specimens decreased from $1,600^{\circ}C$ to $1,400^{\circ}C$. As results of X-ray diffraction patterns, all $La_{9.33}(Si_{6-x}V_x)O_{26}$ specimens showed the formation of a complete solid solution in a apatite polycrystallin structure. But the specimens doped with more than 1.5mol% showed the second phase, $La_2SiO_5$ and $SiO_2$. The specimen dopants with 1.0 mol% showed the maximum ion conductivity. Ion conducting and activation energy of the $La_{9.33}(Si_5V_1)O_26$ specimens were about $7.8{\times}10^{-4}S/cm$ 1.62 eV at $600^{\circ}C$, respectively.

• 자원환경지질
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• 제20권3호
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• pp.169-177
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• 1987

The Manjang copper magnetite-fluorite orebodies are imbedded within the limestone beds of the Hwajonri Formation. The ore deposits are characterized by magnetite-fluorite bearing skarn orebody in the west orebody and copper sulfide veins of the central and main orebodies. This study includes fluid inclusion geothermometry, salinity analysis, stable isotope analysis, and application of phase rule to mineral associations in skarn ore. Ore minerals are closely associated with the skarn silicates such as garnet, wollastonite and epidote. Magnetite and fluorite are remarkable in the west orebody whereas chalcopyrite is dominate in the central and main orebodies where pyrite and pyrrhotite also appear as sulfide gangues. Homogenization temperature and salinity of fluid inclusions are measured ranging between $240^{\circ}C$ and $350^{\circ}C$, 6.3~12.9 wt. percent in quartz and $220^{\circ}C$ and $350^{\circ}C$, 8.5~9.9wt. percent in fluorite, respectively. This indicates that the filling temperature and salinity are higher in quartz than in fluorite with the tendency of both to be linearly decreased suggesting an attribution of meteoric water to the mineralization. $T-fo_2$ diagram in the Ca-Fe-Si system at 1 kb and $Xco_2$=0.02 shows that the mineral assemblages with decreasing temperature are andradite-hedenbergite-calcite, hedenbergite-andradite-quartz, magnetite-andradite-quartz, and magnetite-quartz-calcite, indicating that magnetite crystallizes mostly late skarn stage at lower temperature. According to the carbon and oxygen isotopic values of the host limestone and calcite in ores, the sourec of carbon might be mixture of host limestone and deep seated carbons. Sulfur isotope data imply that ore fluids be relatively homogeneous in sulfur isotopic composition, mainly derived from igneous source.