• 제목/요약/키워드: $MgO-P_2O_5$

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Na2O-MgO-P2O5 생체 유리의 탄성계수와 용해도 (Elastic Moduli and Dissolution Rates of Resorbable Na2O-MgO-P2O5 Bioglasses)

  • 한동빈
    • 한국세라믹학회지
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    • 제26권6호
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    • pp.850-854
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    • 1989
  • The elastic moduli and dissolution rates of 15 glasses with different mole ratios of sodium-magnasium-phosphate as potential non-toxic biomaterials were investigated. In this study, a 3-pint bending test, sonic resonance technique, and theoretical calculation were used to evaluate the modulus of elasticity. The dissolution rates at 37$^{\circ}C$(human body temperature) were determined by the measurement of mass changes in each sample for 24 weeks.

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미생물비료 생물자원인 불용성인산 가용화 세균의 분리, 동정 및 생리적 특성 (Isolation, Identification and Physiological Characteristics of Biofertilizer Resources, Insoluble Phosphate-Solubilizing Bacteria)

  • 손홍주
    • 미생물학회지
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    • 제39권1호
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    • pp.51-55
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    • 2003
  • 환경친화적인 미생물인산비료를 개발하기 위하여 불용성 인산을 가용화 시킬 수 있는 세균을 콩의 근권 토양으로부터 분리하였다. 분리균주의 분류학적 위치를 검토한 결과, Pantoea agglomerans로 동정되었다. 불용성 인산인 $Ca_{3}(PO_{4})_{2}$)로부터 가용성 인산을 생성하기 위한 최적 배지 및 배양조건은 glucose 3%, $NH_{4}NO_{3}$ 0.1%, $MgSO_{4}\cdot\7H_{2}O$ 0.02%, $CaCl_{2}\cdot\2H_{2}O$, 0.06%,초기 pH 7.5, 배양온도 $30^{\circ}C$이었으며, 최적조건에서 배양 5 일 후,898 mg/L의 인산이 생성되었다. 불용성 인산 가용화 기작은 유기산 생성에 의한 배양액의 pH감소와 밀접한 관계가 있었다. 분리균주는 $CaHPO_{4}$, hydroxyapatite로부터 각각 698,912 mg/L의 가용성 인산을 생성하였으나 $FePO_{4}\cdot\4H_{2}O$, $AIPO_{4}$로부터는 각각 28,19 mg/L.의 가용성 인산을 생성하였다.

AlF3-(Mg+Sr+Ba)F2-P2O5계 유리에 관한 연구 제2보 : MgF2의 영향 (Studies on AlF3-(Mg+Sr+Ba)F2-P2O5 Glasses II. Effect of MgF2 Contents)

  • 김정은;이종근
    • 한국세라믹학회지
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    • 제24권3호
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    • pp.277-281
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    • 1987
  • The various contents of MgF2 from 0 to 12.5wt% are studied in the AlF3-(Mg+Sr+Ba)F2-P2O5 system for the effects of various properties in glasses and the atmosphere of melting was controlled by N2 and Ar gas respectively. Density, refractive index, infrared transmission, thermal conductivity and thermal expansion coefficient of glasses are determined. Density, refractive index and thermal conductivity are decreased, micro-hardness and thermal expansion coefficient are increased according to the increasing of MgF2 contents. Infrared transmittance decreases with increasing the MgF2 contents and it slightly dropped by air than N2 and Ar atmosphere. Other properties are not influenced by atmosphere control.

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$CaO-MgO-Al_{2}O_{3}-SiO_{2}-P_{2}O_{5}$계 Bioglass-Ceramic의 결정화 조건에 따른 기계적 성질 및 생체적합성에 관한 연구 (MECHANICAL PROPERTIES AND BIOCOMPATIBILITY WITH CRYSTALLIZATION CONDITIONS OF $CaO-MgO-Al_{2}O_{3}-SiO_{2}-P_{2}O_{5}$ BIOGLASS-CERAMIC SYSTEM)

  • 최현미;이민호;배태성;박찬운
    • 대한치과보철학회지
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    • 제34권1호
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    • pp.169-186
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    • 1996
  • The purpose of this study was to investigate the mechanical properities and biocompatibility with crystallization temperature and time of a bioactive glass-ceramic system $41.4wt%SiO_{2}-35.0wt%CaO-3.0wt%MgO-12.0wt%P_{2}O_{5}-8.6wt%Al_{2}O_{3}$ with same molar percent of $Al_{2}O_{3}\;and\;P_{2}O_{5}$. The crystallization behaviors were investigated with DTA, XRD and SEM. Fracture toughness with the change of crystallization temperature and time was measured by indentation fracture method. Also, biocompatibility was evaluated by culture of mouse fibroblast cell line L929. The results obtained were as follows ; 1. The major crystalline phases were apatite and anorthite, and relative intensity of anorthite phase was increased at $1004^{\circ}C$. 2. The hardness and fracture toughness were gradually increased with the increase in ceraming temperature to $1004^{\circ}C$. 3. When the glass ceramic was heat-treated for 4 hours at ceraming temperature of $1004^{\circ}C$, hardness and fracture toughness showed the maximum values $578.84k/mm^2\;and\;2.07MPa\;m^{1/2}$, respectively. 4. The growth rate and cytotoxic of L929 fibroblast cells for bioactive glass ceramic were better than those of stainless steel and titanium.

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입도분포에 따른 하상퇴적물의 지구화학적 분산 및 부화 (Geochemical Dispersion and Enrichment of Fluvial Sediments Depending on the Particla Size Distribution)

  • 이현구
    • 자원환경지질
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    • 제32권3호
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    • pp.247-260
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    • 1999
  • Geochermical characteristics of the fluvial sediments deprnding on particle size distribution size were investigated in the respect of majir, minor and rare eath element chemisitry. Ratios of $Al_{2}O_{3}/Na_{2}O$ and $K_{2}O/Na_{2}O$ of the sediments show the homogeneous valus, and partly positive correlation with $SiO_{2}/Al_{2}O_{3}$, respecively. Characteristics of minor element ratios (V/Ni, Cr/V, Ni/Co and Zr/Hf)are within the lower and narrow range. Thesesuggested that sediment sources may be acidic to intermediate granitic rock, and may be explained by simple weathering and sedimentation. With increasing SiO2 contents, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO and MgO decreased, but those of $K_{2}O$ and $Na_{2}O$ increased, Concentrations of Ba, Be, Cs, Cu, Li, Ni, Sr, V and Zr show comparatively normal negative and some positive trends. Compared with the mean composition of granite, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, MnO, CaO and MgO in the sediments of the study area were highly enriced. Among some minor and rare earth elements, concentrations of As, Cd, Cu, and V were enriched, but those of Be, Ce, Rb, Sc, Sr and Zn were depleted when compared with average composition of granite. By decreasing of particle size fractions, SiO2, Rb and Sr conterts decreased, but concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO, MgO, $TiO_{2}$, MgO, $P_{2}O_{5}$, Be, Cu, Hf, Pb, V and Zr increased. From the correlations between particle size fractions and element concenreations, some elements of $Fe_{2}O_{3}$, CaO, MgO, $P_{2}O_{5}$, Cu, Ni, Zn and Zr showed typical trends in the secondary contramination sediments. These trends are typically shown under 100 mesh fractions. It indicates that the fraction of minus 100 mesh is the optimum size fraction for geochemical and environmental survey.

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X-선 형광분석법에 의한 포틀란드 시멘트의 정량분석 (X-ray Fluorescence Analysis of Chemical Ingredients for Portland Cement)

  • 임헌진;백연봉;김도생;윤준수;이경원
    • 한국세라믹학회지
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    • 제33권8호
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    • pp.928-934
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    • 1996
  • X-선 형광분석법을 사용하여 표준검정곡선법으로 시멘트 중의 주, 부성분들을 정량하고 습식법과 분석결과를 비교하였다. 이때, 표준시료 및 미지시료는 용융 케스트 비드법으로 준비하였다. 표준시멘트(227A372)의 오차분석결과 주성분인 CaO, SiO2, Al2O3, Fe2O3 및 부성분중의 MgO, SrO는 상대오차가 1% 이내이었으며, 부성분중 So3, K2O, TiO2, Na2O P2O5 및 Mn2O3는 5% 이하의 상대오차를 가졌다. 부성분의 상대오차는 시료준비오차가 가장 큰 부분을 차지하였다. X-선 형광분석과 습식분석을 비교한 결과 시멘트 분석의 측정값간의 최대혀용범위를 만족하므로, X-선 형광분석법을 시멘트 화학분석에 적용할 수 있을 것으로 판단된다. 그리고, 기존의 습식법으로 분석하기 어려운 시멘트내에 존재하는 미량성분인 P2O5, SrO 및 Mn2O3 의 정밀정확한 분석 또한 가능하였다.

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MgO.$P_2O_5$ 유리의 수분 측정 (Determination of Water in Magnesium Metaphosphate Glasses)

  • 강은태;박용완
    • 한국세라믹학회지
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    • 제23권3호
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    • pp.94-98
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    • 1986
  • Infrared has been used in determination of water in magnesium metaphosphate glasses. The method consisted of measuring the weight loss and the variation in absorption coefficient at 3, 200$cm^{-1}$. The molar absorptivity of water in magnesium metaphophate glasses was found to 76.9ι$mol^{-1} cm^{-1}$ Using the value for $\varepsilon$, A and Δ$\upsilon$H of the hydroxyl band in the spectra of magnesium metaphosphate. The molar absorptivity of the hydroxyl absorption band at 3, 3130-2, $925cm^{-1}$ in the spectra of MgO.$P_2O_5$ system glasses could be computed. And a variation of molar absorptivity against the MgO/P2O5 ratio has not been shown regulation.

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FeO-MnO-CaO-SiO2-MgOsatd. 슬래그에서의 P의 열역학적 거동 (Thermodynamic of Phosphorus in FeO-MnO-CaO-SiO2-MgOsatd. Slag Systems)

  • 조문경;박경호;민동준
    • 대한금속재료학회지
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    • 제47권3호
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    • pp.188-194
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    • 2009
  • Recently, new extraction technology for manganese nodule has been developed as alternative noble metallic resources. It is important to understand thermodynamic behaviors of phosphorus in low basic slag system from the viewpoint of the refining processing optimization. Thermodynamic behaviors of phosphorus in the $FeO-MnO-CaO-SiO_2-MgO_{satd.}$ slag system were investigated at 1723 K with various oxygen potential and slag composition of low basicity. The experimental results for dependence of phosphorus on oxygen potential and slag basicity indicated that the dissolution mechanism of phosphorus into slag of low basicity could be derived as follows; $[P]+5/4O_2+(O^{2-})=({PO_{3.5}}^{2-})$ Present experimental results implied that stability of phosphorus in slag would be depended on both of $O^{2-}$ (basicity) and content of $Ca^{2+}$ in molten slag. The thermodynamic effect of FeO, MnO and $Na_2O$ on low basicity on phosphate capacity was discussed.

라만과 적외선 분광기를 이용한 P2O5-Na2O-MgO 유리의 이상성에 관한 연구 (Abnormality of P2O5-Na2O-MgO Glasses by Raman and Infrared Spectroscopy)

  • 이병철;권용준;류봉기
    • 한국세라믹학회지
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    • 제39권3호
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    • pp.265-271
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    • 2002
  • 용융법으로 제작된 인산염 유리시편의 조성변화에 따른 밀도와 물에 대한 안정성 및 각각의 구조변화를 조사하기 위해 Raman과 적외선 흡수 스펙트럼이 측정되었다. 그 결과 $P_2O_5$가 60mol% 부근에서 밀도와 물에 대한 안정성이 급격히 증가하는 구조적인 이상성을 나타내었다. 이러한 변화는 $Mg^{2+}$ 이온을 중심으로 DBO(Double-Bonded Oxygen)이 배위하면서 유리구조의 강한 수축을 유발시켜 나타난 구조변화에 기인하는 것으로, $Mg^{2+}$ 이온을 배위하고 있는 DBO은 이중결합의 성격을 잃어버리고, 다른 하나의 NBO(Non-Bonding Oxygen)과 함께 공명구조를 이룬다고 생각된다.