• Economic and Environmental Geology
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• v.29 no.1
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• pp.11-21
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• 1996

The first Mg-skarn minerals are found from magnetite ore deposits of the Janggun mine, Korea. The skarn minerals are composed of mostly chondrodite, olivine， chlorite, serpentine, phlogophite, talc, apatite, magnesite， dolomite, siderite and trace amount of clinopyroxene, amphibole, garnet, wollastonite associated with magnetite, pyrrhotite and pyrite. The skarn zone is developed in the magnetite deposits at the contact of the Mg-rich Janggun Limestone Formation and the Chunyang granite. The chondrodites are columnar and radial shapes and some of them show twins. The chemical compositions of twinning-type chondrodites have high FeO (4.63 to 5.6 wt%), MnO (0.26 to 0.46 wt%) and low MgO (55.02 to 56.18 wt%) relative to the radial-type chondrodites. Twinning in chondrodite has been formed in close relation to substitution between Mg and Fe + Mn in humite solid solution. Temperature, $-logfo_2$ and $X_{CO2}$ during the skarn stage of magnetite deposits from the Janggun mine range from 395 to $430^{\circ}C$, from 30.5 to 31.2 atm and from 0.06 to 0.09, respectively.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.485-490
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• 1994

A restriction endonuclease, PsyI, has been isolated from Pseudomonas syringae pv. pha- seolicola, and its catalytic properties have been studied. This enzyme was purified through strepto- mycin sulfate and ammonium sulfate fractionation, phosphocellulose Pll, DEAE-cellulose, hydroxy- apatite and Sephadex G-100 column chromatography. It's molecular weight was about 50,000 dalton as determined by 7.5% polyacrylamide gel electrophoresis containing 0.1% SDS. In catalytic proper- ties, PsyI shows stable at wide ranges of pH between 7.0 and 10.0, of temperature between 30$\circ$C and 37$\circ$C, and its thermal stability is between 25$\circ$C, and 45$\circ$C, at the presence Of 10 mM MgCl$_{2}$-PsyI essentially require Na salt for enzyme reaction, is rather inhibited in the high Na salt concent- ration. The presence of 2-mercaptoethanol is absolutely required for the enzyme activity. This endonuclease, PsyI was determined to be an isoschizomer of SalI from the results of the restriction mapping and DNA sequencing.

• Transactions on Electrical and Electronic Materials
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• v.16 no.4
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• pp.194-197
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• 2015

La_9.33(Si₅V₁)O₂₆ ceramics were fabricated by the mixed oxide method for solid oxide electrolytes. La_9.33(Si₅V₁)O₂₆ specimens showed the hexagonal, space group P63 or P63/m, and the unit cell volume increased when the sintering temperature increased. The specimen sintered at 1,400℃ showed the X-ray patterns of the homogeneous apatite single phase without the second phase, such as La₂SiO₅ and SiO₂. The specimen sintered at 1,400℃ showed the maximum sintered density of 4.93 g/cm³. When the sintering temperature increased, the electrical conductivities increased, the activation energy decreased and the values were 7.83×10⁻⁴ S/cm, 1.61 eV at 600℃, respectively.

• Korean Journal of Materials Research
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• v.17 no.8
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• pp.408-413
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• 2007

Process of the hydroxyapapite(HA) precipitation on bioactive titanium metal prepared by NaOH in a modified-simulated body fluid(mSBF) was investigated by high resolution transmission electron microscope (HRTEM) attached with energy dispersive X-ray spectrometer(EDX). The amorphous titanate phase on titanium surface is form by NaOH treatment and an amorphous titanate incorporated calcium and phosphate ions in the liquid to form an amorphous calcium phosphate. With increasing of soaking time in the liquid, the HA particles are observed in amorphous calcium phosphate phase with a Ca/P atomic ratio of I.30. The octacalcium phosphate (OCP) structure is not detected in HRTEM image and electron diffraction pattern. After a long soaking time, the HA particles grow as needle-like shape on titanium surface and a large particle-like aggregates of needle-like substance were observed to form on titanium surface within needle-like shape. A long axis of needle parallels to c-direction of the hexagonal HA structure.

• Corrosion Science and Technology
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• v.19 no.2
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• pp.51-56
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• 2020

The objective of this study was to improve properties of plasma sprayed HAp layer to titanium substrate by introducing an intermediate layer with two different methods. Before applying Zn doped HAp coating on titanium substrate, an intermediate layer was introduced by titanium plasma spray or titanium anodization. Heat treatments were conducted for some samples after titanium intermediate layer was formed. Zn doped HAp top layer was applied by plasma spraying. Three-point bending test and pull-off adhesion test were performed to determine the adhesion of Zn doped HAp coatings to substrates. Long-term credibility of Zn doped HAp plasma sprayed coatings on titanium was assessed by electrochemical impedance measurements in Hanks' solution. It was found that both titanium plasma sprayed and titanium anodized intermediate layer had excellent credibility. Strong adhesion to the titanium substrate was confirmed after 12 weeks of immersion for coating samples with titanium plasma sprayed intermediate layer. Samples with titanium anodized intermediate layer showed good bending strength. However, they showed relatively poor resistance against pulling off. The thickness of titanium anodized intermediate layer can be controlled much more precisely than that of plasma sprayed one, which is important for practical application.

• Ocean and Polar Research
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• v.23 no.1
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• pp.51-62
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• 2001

The Arctic consists of numerous sedimentary basins containing voluminous natural resources and two of the world's major oil and gas producing areas. The western Siberia Basin in the Arctic region has the largest petroliferous province with an area of 800 ${\times}$ 1,200 km and produces more than 60% of total Russian oil production. The North Slope of Alaska produces about 20% of the U.S. output, i.e., 11% of the total U.S. consumption. Being small compared to those regions, the Canadian Northwest Territories and the Pechora Basin in Russia produce only fair amount of oil and natural gas. There are also many promising areas in the northern continental shelf of Russia. In addition to Russia, Svalbard and Greenland have been investigated for oil and gas. Gas hydrates are widespread in both permafrost regions and arctic continental shelf areas. The reserves of gas hydrates in the Arctic Ocean are about 20${\sim}$32% of total estimated amounts of gas hydrates in the world ocean. Mineral mining is well developed, especially in Russia. The major centers are located around the Kuznetsk Basin and Noril'sk. They are major suppliers of gold, tin, nickel, copper, platinum, cobalt, iron ore, coal as well as apatite. There are also some minings of lead-zinc in Alaska and Arctic Canada.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.44.1-44.1
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• 2009

최근 경조직 재생 (hard tissue regeneration) 에 대한 연구가 활발히 진행되고 있다. 그러나 이와같은 연구는 결손도입의 어려움 및 이차적인 골절의 위험성 때문에 대형동물을 중심으로 진행되고 있으며, 그 결과 동물실험에 있어서 시간적 경제적으로 큰 리스크를 수반한다. 그러나 유전자 변형동물의 대부분은 마우스이며, 분자생물학적 관점에서 골재생의 과정을 이해하기 위해서는 마우스를 이용한 골재생 모델의 확립이 필요하다. 따라서 본 연구에서는 마우스를 통해 경조직 재생모델의 제작방법을 검토함과 동시에, 골재생부위에 대한 골질 (bone quality) 및 골양 (bone quantity) 평가의 방법을 수립하는 것을 목적으로 하였다. 골결손은 생후 8주의 마우스에 시술하였다. 치과용 드릴을 이용하여 경골 (tibia) 길이의 30 % 부근의 내측(medial) 면에서 골수강 (marrow cavity) 방향으로 $500\;{\mu}m\varphi$의 원주형 결손을 도입하였다. 시술 후의 골재생과정을 관찰하기 위해 ${\mu}CT$ (SMX-100CT: Simazu) 를 이용하여 주기적으로 촬영하였으며, 골양 (BV/TV) 의 회복과정은3D-bon (RATOC) 을 이용하여 정량적인 해석을 수행하였다. 그리고 재생부의 골질 (아파타이트 배행성; BAp orientation) 평가는 투과형micro-beam XRD (R-AXIS BQ: Rigaku)를 이용하여 수행하였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.45.1-45.1
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• 2009

In this study, we investigated a calcium phosphate-calcium sulfate injectable bone substitute (IBS) with organic reinforcement of chitosan, citric acid and hydroxypropyl-methyl-cellulose (HPMC). The powder component of IBS consisted of tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dihydrate (CSD). The liquid component was a solution of citric acid and chitosan. The effect of HPMC in terms of setting time, compressive strength and apatite forming ability on this IBS was investigated. The mass content of HPMC in liquid phase was varied in array of 0%, 2%, 3% and 4%. The setting times obtained between 20 and 45 minutes. Compressive strength was achieved over 20 MPa after incubation at 370C and in 100% humidity for 28 days. Porosities were evaluated in relation with compressive strength. Elastic moduli of the 28 days after-incubation IBS were obtained around 4GPa

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1105-1113
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• 2000

Bioglass 조성 중 45S5 (46.1SiO$_2$.24.4$Na_2$O.26.9CaO.2.6P$_2$O$_{5}$ : 몰비)를 기본 조성으로 하여 46P4 (46.2SiO$_2$.49.5CaO.4.3P$_2$O$_{5}$ : 몰비), 46SF (46.1SiO$_2$24.4$Na_2$O.16.1CaO.2.6P$_2$O$_{5}$.10.8CaF : 몰비) 그리고 55SF (55.1SiO$_2$.9.2$Na_2$O.27.8CaO.3.4P$_2$O$_{5}$.4.5CaF : 몰비)를 제조하여 tris-완충용액 및 유사 생체용액(simulated body fluid)에서 반응시킨 후 생체활성유리의 표면에 생성되는 아파타이트 결정형에 관하여 연구하였다. 45S5 유리를 tris-완충용액에 반응시켰을 경우 6시간 반응시부터 수산화 아파타이트가 생성되었으나 유사 생체용액에 반응시켰을 경우에는 24시간까지도 수산화 아파타이트 결정이 생성되지 못하고 비정질 상태의 칼슘 인산염만 형성되었다. tris-완충용액에 각 조성의 유리를 200시간 반응시킨 경우 불소를 함유하지 않은 유리에서는 잎사귀 모양의 수산화 아파타이트가, 불소를 함유한 유리에서는 구상의 플루오르 아파타이트가 형성되었다. 그러나 유사 생체용액에 각 조성의 유리를 200시간 반응시켰을 경우 불소를 함유하지 않은 유리에서는 누에고치형의 수산화 아파타이트가 형성되었고 불소를 함유한 유리에서는 무정형의 칼슘 인산염이 생성되었다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.14-14
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• 2011

폴리우레탄 필름을 이용하여 등산복, 스포츠 웨어, 보호복 등 많은 의복이 제조되고 있으며, 현재 폴리우레탄 필름에 항균성을 부여하여 메디컬 소재에 적용되고 있다. 항균성을 부여하는 물질은 제올라이트. 수산화아파타이트, 실리카 겔을 이용한 많은 무기 항균제가 사용되고 있다. 이들중 특히 수산화아파타이트는 생체친화력 및 이온교환 능력이 우수하여 인공뼈 또는 인공치아로 사용되고, 환경분야에서는 이온교환수지로 중금속 제거를 위하여 사용되기도 한다. 본 연구에서는 폴리우레탄 필름 내부의 비드 간극 및 크기를 제어하여 비드콘 구조를 가지는 폴리우레탄 필름을 제조하였고 수산화아파타이트에 다양한 조건으로 은이온을 흡착시켜 은의 최적 흡착 조건을 설정하고 은이 흡착된 수산화아파타이트의 입자를 제어하여 다양한 종류의 입자를 제조하고 입자별 항균성을 평가하였다. 최종적으로 개발된 비드콘 폴리우레탄 필름과 은담지 수산화아파타이트를 여러가지 조건으로 복합화하여 항균성을 가지는 아파타이트복합 폴리우레탄필름을 제조하고 개발된 필름의 항균성 및 그 특성을 분석하여 보았다.