• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.139-142
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• 2004

본 논문은 광산산성배수(AMD)에서 철 및 알루미늄 제거 효과가 입증된 인회석을 이용하여 ARD (Acid Rock Drainage)에서의 비소저감 능력을 알아보고 고품위 석회석과 정화효율을 비교하기 위하여 실내실험을 실시하고 그 결과를 이용 인회석 배수로를 설계하는 것을 연구목적으로 하고 있다. 실험결과, pH, 비소제거율 및 석회석/인회석의 용해량은 유속이 증가함에 따라 감소하는 것으로 나타났으며 유속이 0.6 ml/min/kg 정도에서 인회석은 침출수 중 비소를 100% 제거하는 것으로 확인되었다. 유속에 따른 용해율은 인회석이 석회석보다 10배 정도 높은 것으로 나타났다.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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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.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.05a
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• pp.173-175
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• 2001

흡착에 필요한 최적의 세라믹 볼의 소성온도는 93$0^{\circ}C$가 가장 적당하다. 공업용수 중에 용존되어 있는 유기물 및 유해성분이 제거(COD나 $BOD_{5}$)가 가능하다. Fe와 Pb의 중 금속 제거의 경우 Pb의 경우가 제거 효율이 더 크며, 이에 따른 mechanism으로 이온교환이온이 Pb의 경우 2가 양이온이기에 더욱 효율이 크고 Fe의 경우는 수화하여 구조적인 붕괴를 일으키며, 2가와 3가의 공존하므로 Pb보다 제거율이 낮다. Fe와 Pb 중금속수를 1시간 동안 제거하여 Freundlich형 등온식에 따른 계산 결과 5,10ppm에서 1/n의 수치가 2 이상을 넘지 않고 있고, 500, 1000ppm의 경우는 등온이온교환으로 할 때 1/n의 수치가 2에 근접하므로 분말의 경우에 비해 제거율이 낮지는 않다. 그러므로 경제적 이점과 재활용면에서 볼의 사용이 우수하다는 것을 알 수 있다. 장치의 용기에 비례하여 볼 때 볼의 양은 600g이 가장 적당한 양이다. 등온교환의 경우 Apatite(HAp)를 이용한 분말의 제거율 보다 약간 낮으나 분말의 경우 사용 후 취급이 용이하지 않고 2차적 오염이 예상되므로 세라믹 볼의 경우 환경친화성재료로 여러 가지의 수처라 공정에 적용이 가능할 것으로 판단된다.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.355-362
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• 1987

본 실험의 목적은 치아 회분이 입자 크기에 따라 골형성에 어떠한 영향을 주며 순수 합성수산화 apatite인 calcitite와는 어떠한 차이가 있는가를 평가하기 위하여 수행하였다. 이를 위하여 200mesh와 40mesh의 치아 회분말과 40mesh calcitite를 잡종견의 신선한 발치와에 매식후 1주, 2주, 3주, 4주에 각각 희생하여 임상, X-선상 및 현미경적으로 관찰한 바 다음과 같은 결론을 얻었다. 1. 모든 경우에 조직의 거부반응이 없었다. 2. 40mesh치아 회분의 경우가 200mesh의 치아회분의 경우 보다 골 형성 능력이 현저히 높았다. 3. 40 mesh 치아회분과 calcitite 모두 비교군에 비하여 골 형성이 지연되었다. 4. 40 mesh 치아 회분과 calcitite의 골 형성 능력은 유사하였다.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.81-86
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• 2007

This paper describes a study on the role of limestone which might affect the dissolution of phosphates when phosphate containing sediments are put under anaerobic conditions. A small quantity of calcium hydroxy-apatite, alone or mixed with limestone powder, was put in contact with aqueous solution of acetic acid or carbonic acid, and variations of phosphate concentration were determined time dependantly. The results showed that the concentration was remarkably low in the presence of limestone, signifying that the coexistence of limestone suppresses the dissolution of phosphate by organic acid and/or carbonic acid. Separate experiments conducted by developing an anaerobic condition, after mixing lake sediments with dried leaves and limestone, showed that the existence of limestone suppressed the dissolution of phosphate. These results show that the application of limestone might be a useful measure to prevent deterioration of water quality originated from eutrophication by inhibiting the internal loading of P in eutrophic water-bodies.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.102.2-102.2
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• 2012

Different layers of zirconium nitride (ZrN) and hydroxyapatite (HA) coatings were prepared on cp Ti substrate for biomedical applications. The main idea is to improve the mechanical strength as well as the biocompatibility of the coating. ZrN is known for its high mechanical strength, corrosion resistance. HA is well known for its biocompatibility properties. Hence, in this study, both materials were coated on a cp Ti substrate with bottom layer with ZrN for good bonding with substrate and the top layer with HA for induce bioactivity. Middle layer was formed by a composite of HA and ZrN. Detail analyses of the layered coatings for its structural, morphological, topographical properties were carried out. Then the mechanical property of the layered coatings was analyzed by nanoindentation. Biomimetic growths of apatite on the functionally graded coatings were determined by simulated body fluid method. This study provides promising results to use this kind of coatings in biomedical field.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.770-776
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• 2005

Hardening and hydroxyapatite(HAp) formation behavior of the bioactive cements in the system of $CaO-SiO_{2}-P_{2}O_{5}$ glasses and the corresponding glass-ceramics were studied. DCPD (Dicalcium Phosphate Dihydrate: $CaHPO_4{\cdot}2H_2O$) and DCPA (Dicalcium Phosphate Anhydrous: $CaHPO_4$) were developed when the prepared glass and glass-ceramic powders were mixed with three different solutions. The DCPD and DCPA transformed to HAp when the cement was soaked in Simulated Body Fluid (SBF), and this HAp formation strongly depended on the releasing capacity of $Ca^{2+}$ ions from the cements. The glass-ceramic containing apatite showed fast setting, but no HAp formation was observed because no $Ca^{2+}$ ions were released from this glass-ceramics. The compressive strength of the cements increased with reaction time in SBF until all DCPD and DCPA transformed to HAp.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.652-656
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• 2007

Hydroxyapatite [Ca10(PO4)6(OH)2, HAp] and titanium(Ti) metal are known to be excellent materials with high affinities for natural bone through the apatite. Tricalcium phosphate [Ca3(PO4)2, TCP] is a promising alternative material because it is similar to HAp in its physical properties and biocompatibility. To examine the influence of hydroxyapatite, tricalcium phosphate, pure titanium and pre-treated titanium on osteopontin expression in osteoblasts, RNA was extracted from proliferated and cultured osteoblast cells and OPN mRNA expression was observed by RT-PCR.

• Korean Journal of Materials Research
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• v.14 no.4
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• pp.287-292
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• 2004

A bio-composites were prepared by mechanical mixing with bioactive sol-gel derived $CaO-SiO_2$ and organic PEEK for bone repairing hybrid materials. The composites were characterized by in-vitro test. A bonelike apatite was formed on the surface of all bio-composites in SBF test. The cell morphology and adhesion on the surface of the composites having below 30% PEEK were clearly observed in L929 cell experiment.

• Journal of the Korean Chemical Society
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• v.13 no.1
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• pp.62-67
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• 1969

The adaptabilities of various nitrohumates (-K, -Na and $-NH_4$ salt) as a soil conditioner and a raw material for soluble phosphatic fertilizer were studied. 1. Nitrohumates (especially $-NH_4$ salt) protect the soil from fissures and control the phosphoric acid adsorptive functions of soils considerably. 2. Most effective nitrohumic acids as a soil conditioner were prepared with 15% $HNO_3$ solution composed of five times of original humic acids (by weight) at $80^{\circ}C$ for 2 hrs under continuous stirring. 3. When 50% (by weight) of $NH_4$-nitrohumate were added to apatites in water and boiled for 2 hrs, maximum 26% of $P_2O_5$(apatite contains 37% of $P_2O_5$) were changed into water soluble forms.