• 대한화학회지
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• 제65권4호
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• pp.249-253
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• 2021

안동에 있는 한 가축 농가의 우사에서 깔짚과 퇴비를 채취하였다. 이들 시료로부터 질소(N)와 인(P)의 성상의 변화를 조사하고 이들을 유용하고 현실적으로 제거할 수 있는 방안을 제시하고자 하였다. 시료의 조성 및 그 함량은 X-선 형광 분석기(XRF)로 확인하였다. 시료에서 용출되어 나오는 아질산성질소(NO₂^-), 질산성 질소(NO₃^-), 인산이온(PO₄^3-)들은 이온 크로마토그래프로, 암모니아성 질소(NH₄⁺), 총인(T-P), 총질소(T-N)는 자외선/가시광선 분광기를 이용하여 분석하였다. 연구의 결과로서, 소의 배설물 초기 상태에 있는 암모니아성 질소는 pH를 상승시켜 바로 휘발시킬 수 있는 암모니아 가스 상태로 만들 필요성이 있다. 녹조류 증식의 주요 영양원인 질소와 인은 퇴비의 발효를 촉진시킨 후 칼슘(Ca)과 마그네슘(Mg)을 첨가하여 인은 인산칼슘(CaHPO₄·3H₂O), 질소는 스투루바이트(NH₄MgPO₄·6H₂O) 형태의 난용성염을 생성 시킴으로서 제거 할 수 있다.

• 한국세라믹학회지
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• 제35권4호
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• pp.339-346
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• 1998

Active belite cement clinkers were synthsized by using natural raw materials with borax and calcium phosphate ({{{{ {Ca }_{3 }( {PO}_{4}) }}2) In both case {{{{alpha ^、 {C }_{2 }S }} were formed but borax was more efficient. The cement syn-thesized with the addition of borax was hydrated with the addition of anhydrite(5 wt%) and slag(30wt%, 40wt% 50wt%) The addition of 50wt% slag with anhydrite was good for strength development in 7days and the compressive strength was developed to twice than no addition of slag at 28 days strength.

• 한국환경과학회지
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• 제16권6호
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• pp.677-682
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• 2007

This study was performed to provide the basic information on characteristics of groundwater pollution in Gyeongsan city. Forty two groundwater samples were collected, and pH, DO, COD, $NH_3-N,\;NO_3^--N$, T-N, $PO_4^{3-}-P$, Cl, Ca, Mg, hardness, evaporate residues and others were investigated. And, ANOVA analyses were carried out to reveal the differences in water pollution indicator values of by industry, commerce/residence and agriculture areas. The results were as follows. 1. The mean values of pH, DO, COD, $NH_3-N,\;NO_3^--N$, T-N, $PO_4^{3-}-P$, Cl, evaporate residues, Ca and hardness were 6.9, $7.9mg/\ell,\;0.4mg/\ell,\;2.44mg/\ell,\;2.73mg/\ell,\;6.06mg/\ell,\;0.82mg/\ell,\;32.72mg/\ell,\;381.67mg/\ell,\;41.53mg/\ell,\;177.17mg/\ell$, respectively. 2. As groundwater became deeper, the values of Cl, Ca, Mg, Na, hardness and evaporate residues remarkably increased, but those of COD, $NH_3^--N,\;NO_3^--N,\;NO_2^-N$, T-N decreased. 3. The values of COD, Cl, Ca, Mg, Na, hardness and evaporate residues were very high in industrial area, and those of $NH_3-N,\;NO_2^--N$, T-N were very high in commercial/residential area, and those of $NO_3^--N$ were a little high in agricultural area. 4. The correlations between depth and each value of Mg, Na, Fe, hardness and evaporate residues were highly positive, and those between DO and each value of Mg, Cu, Fe, hardness and evaporate residues were highly negative. 5. According to ANOVA analyses, the differences in three area groups (industry, commerce/residence and agriculture) on the values of $NH_3-N$, T-N, evaporate residues, hardness, Ca, Mg, K and Fe were significant at 1% level.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
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• pp.3-26
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• 1999

We have successfully grown <111>-oriented (La,Sr)(Al,Ta)$O_3$(LSAT) mixed-perovskite single crystals and <0001>-oriented $Ca_8La_2(PO_4)_6O_2$(CLPA) single crystals with the apatite structure by the Czochralski method. The compositional and lattice parameter uniformity of the crystals are discussed in relation to the growth conditions. Since LSAT and CLPA single crystals have excellent lattice matching with GaN, they ar promising as new substrates for the growth of high quality GaN epitaxial layers.

• 생물환경조절학회지
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• 제14권3호
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• pp.196-202
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• 2005

본 연구는 상토의 보수성 증가를 위하여 혼합되는 acrylamide 계통 고흡수성 수지인 Stocksorb C(STSB)의 수분 흡수 특성, 수분 흡수에 영향을 미치는 각종 무기염의 종류 및 농도, STSB가 침지된 외부용액속의 무기염 농도 변화를 구명하고자 수행하였다. STSB의 수분 흡수량은 증류수에 침지한 경우 약 180 $mL{\cdot}g^{-1}$였다. 1가의 양이온을 포함한 염인 $KH_2PO_4,\;KNO_3$ 또는 $(NH_4)_2SO_4$를 용해시킨 용액의 농도가 높아질수록 흡수량이 저하되었으나 세 종류 양이온의 종류에 따른 차이는 크지 않았다. $Ca(NO_3)_2{\cdot}4H_2O$ 다양한 농도로 용해시킨 용액 속에 STSB를 침지시킨 경우 수분흡수능 저하가 심하여 20 $meq{\cdot}L^{-1}Ca(NO_3)_2{\cdot}4H_2O$ 용액에서 약 25 $mL{\cdot}g^{-1}$ 수분을 흡수하였다. $Mg(NO_3)_2{\cdot}6H_2O$나 $MgSO_4{\cdot}7H_2O$를 용해시킨 용액의 농도가 높아질수록 수분 흡수량이 심하게 저하하였고, 1가의 양이온이 포함된 염을 용해시킨 용액에서보다 그 정도가 심하였다. 그러나 요소의 농도를 증가시킨 용액에서의 수분 흡수량은 저하되지 않았다. 침지전 Hoagland용액의 농도가 높거나, 침지시간이 길어질수록 STSB를 침지시킨 용액에서의 $K^+$및 $NH_4^+-N$의 농도가 점차 높아졌다. Hoagland 용액의 희석배수와 무관하게 침지시간이 길어질수록 외부용액의 $NO_3^--N,\;H_2PO_4^-$ 및 $SO_4^{-2}$ 농도가 약간 상승하였고, 24시간 경과 후 각각 5,300, 250 및 1,500 $mg{\cdot}L^{-1}$ 농도로 분석되었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.369-373
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• 2004

In order to elucidate the possibility of artificial production of p. ferulae by solid-state culture, the optimization of culture conditions was carried out. When $NH_4H_2PO_4$ and $CaCO_3$ were used in the cultures using test tube with 30 g of Populus sawdust at $25^{\circ}C{\pm}1$ in the dark, the favored mycelial growth was observed with $1\%$ of $NH_4H_2PO_4$ and the production of polysaccharide was 7.85 mg/100 mg of mycelium with $1\%$ of $CaCO_3$. The mixtures of $80\%$ of Populus Sawdust and $20\%$ of rice bran at $60\%$ of water content were determined to be optimal for the production of fruiting bodies in the sawdust culture. When three treatments containing various ratios of garlic powder were conducted, yields of fruiting bodies were drasti[ally higher than those of Synthetic mixture without garlic powder The highest yield (143 g/bag) was obtained with $7\%$ garlic powder. The yield of synthetic mixture containing $7\%$ of garlic powder was $83\%$ higher than that of Sawdust culture. The reason why garlic powder did support growth was not clear but it is possible that garlic powder might contain effective components for the formation of fruiting body. The optimal synthetic mixture composition consisted of cotton seed $77\%$, lime $6.4\%,\;K_2HPO_4\;0.2\%,\;KH_2PO_4\;0.2\%,\;CaHPO_4\;0.2\%$, corn flour $4\%$, wheat flour $5\%$, and garlic pow-der $7\%$.

• 생물환경조절학회지
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• 제9권2호
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• pp.85-93
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• 2000

단고추의 자루재배에 의한 양액재배시 NO3--N과 NH4--N의 비유 (8:2와 10:0), 배지 종류에 따른 생육, 수량 및 무기성분 흡수에 미치는 영향을 조사하였다. 배지의 무기성분 중 P, K, Ca 및 Mg는 배지간에 차이가 나타났는데, P 및 Mg는 버미큘라이트+왕겨에서, K는 펄라이트+버미큘라이트에서, 그리고 Ca은 펄라이트+피트모스에서 각각 그 농도가 높았으며, 펄라이트 단용배지에서 가장 낮았다. 다른 성분에 비하여 Ca의 농도가 가장 높았으며, 10:0 양액에 비하여 8:2 양액에서 배지내 무기성분의 농도가 낮았다. 양액의 pH는 NO3-:NH4+ 비율에 따라 배지간에 다소 차이가 있었으나, 10:0에서 안정적이었으며, 8:2에 비하여 약간 높게 유지되었다. 배지별 EC는 펄라이트+버미큘라이트와 버미큘라이트+왕겨에서 높았다. 8:2에서는 1.83∼2.10ds·m-1 범위였고, 10:0에서는 1.78∼1.97 ds·ms-1 범위로 나타나 모든 배지에서 단고추 생육에 적합한 범위를 유지하였다. 초장고 경경은 8:2와 10:0의 경우 배지에 따른 생육차는 없었으며, 엽면적은 버미큘라이트+왕겨에서, 생체중, 건물중 등은 피트모스+훈탄에서 무거웠고, 펄라이트 단용 배지에서 가장 불량하였다. 생육 등은 배지 종류에 따른 영향도 있었으나, 초장, 경경, 엽면적, 생체중 및 건물중 등은 NH4+를 첨가한 8:2 양액에서 배지종류에 관계없이 10:0에 비하여 높게 나타났다. 주당과수 및 주당수량은 8:2에서 버미큘라이트+왕겨에서 17.53개와 1,588g으로 많거나 무거웠으며, 펄라이트 단용배지에서 가장 적었다. 10:0에서의 주당과수는 버미큘라이트+왕겨에서 16.44개로, 수량은 펄라이트+피트모스에서 1,394g 으로 가장 높게 나타났다. 수량성은 배지 종류에 따른 차이도 일부 인정되었으나, 8:2의 모든 배지에서 과수, 주당수량, 평균과정, 과경, 과장 및 상품과율 등이 모두 10:0 양액보다 높게 나타났다. 식물체내의 무기성분은 8:2의 경우 K+ 및 Mg2+는 잎에서 Ca2+은 뿌리에서 많았으며 PO4-은 과실과 줄기에서 많았다. 10:0에서의 무기성분도 8:2에서와 같은 경향을 나타내었으며, 배지간에 무기성분의 차이는 인정되지 않았다. 양액조성에 따른 무기성분 함량의 차이는 K+, Ca2+ 및 Mg2+는 10:0에서, PO4-은 8:2에서 각각 많았다.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.16-23
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• 2012

Objectives: Present study was undertaken to investigate the crystal growth onto synthetic hydroxyapatite (HA) seeds in pH 4.3 and pH 7.0 supersaturated solutions with different fluoride concentrations. Materials and Methods: 8 groups of pH 4.3 and 7.0 calcium phosphate supersaturated solutions were prepared with different fluoride concentrations (0, 1, 2 and 4 ppm). Calcium phosphate precipitates yield crystal growth onto the HA seed surface while solutions flow. For evaluation of crystallizing process, the changes of $Ca^{2+}$, $PO{_4}^{3-}$, $F^-$ concentrations of the inlet and outlet solutions were determined. The recovered solid samples were weighed to assess the amount of minerals precipitated, and finally determined their composition to deduce characteristics of crystals. Results: During the seeded crystal growth, there were significantly more consumption of $Ca^{2+}$, $PO{_4}^{3-}$, $F^-$ in pH 4.3 solutions than pH 7.0 (p < 0.05). As fluoride concentration increased in pH 4.3 solution, $Ca^{2+}$, $PO{_4}^{3-}$, $F^-$ consumption in experimental solutions, weight increment of HA seed, and fluoride ratio in crystallized samples were increased. There were significant differences among the groups (p < 0.05). But in pH 7.0 solution, these phenomena were not significant. In pH 7.0 solutions, analyses of crystallized samples showed higher Ca/P ratio in higher fluoride concentration. There were significant differences among the groups (p < 0.05). But in pH 4.3 solution, there were not significant differences in Ca/P ratio. Conclusions: Crystal growth in pH 4.3 solutions was superior to that in pH 7.0 solutions. In pH 4.3 solutions, crystal growth increased with showed in higher fluoride concentration up to 4 ppm.

• 한국세라믹학회지
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• 제48권3호
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• pp.217-221
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• 2011

Glass-ceramic materials, which consist of glass matrix phase containing crystalline ${\beta}-Ca_3(PO_4)_2$ and ${\beta}-Ca_2P_2O_7$, have been prepared by heating at $750-900^{\circ}C$ of calcium phosphate invert glasses in the silica-free $CaO-P_2O_5-TiO_2-Na_2O$, system. With increasing heating temperature from 750 to $900^{\circ}C$, the crystallite size of precipitated ${\beta}-Ca_3(PO_4)_2$ in glass with $55CaO{\cdot}35P_2O_5{\cdot}3TiO_2{\cdot}7Na_2O$ (mol%) composition increased from 48 to 91 nm. With the extension of the immersion time in dilute acetic acid solution (pH = 5) to ${\geq}$200 min, the degree of dissolution of $Ca^{2+}$ and $P^{5+}$ ions in the glass-ceramics was linearly increased and the solution was constantly maintained at pH = ~7. Biomimetic nanostructured (62-88 nm in average dia.), sphere-shaped hydroxyapatite was homogeneously formed on the surface of the glass-ceramics when socked for 7-14 days in a Hanks' solution, indicating bioactivity of the prepared glass-ceramics.

• Membrane and Water Treatment
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• 제15권3호
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• pp.117-130
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• 2024

The possibility of using lime/mineral solvent solutions has been investigated to effectively remove T-P from wastewater. The lime solvent solution showed an initial T-P removal efficiency of about 90% compared to the less efficient mineral solvent solution removal. High pH and dissolved Ca2+ can form hydroxyapatite minerals (Ca5(PO4)3(OH) or Ca10(PO4)6(OH)2 and can also remove SS and COD from wastewater. Feldspar dissolution solution can be reused twice because the Ca limited sample content provided, but further research is needed to discover other influencing parameters that control the T-P removal efficiency in real wastewater. Because it plays an important role of alkalinity in T-P removal, the success rate is limited. In practical applications, it is obtained according to the pH value wastewater in the environment. The results obtained in this study can highlight new insights on the use of limestone/dissolved mineral solutions to control T-P in wastewater, instead of directly using commercial chemical agents that can produce large amounts of unreacted chemical sludge.