• 기계와재료
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• v.19 no.3 s.73
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• pp.88-98
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• 2007

• 기계와재료
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• v.16 no.3 s.61
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• pp.10-20
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• 2004

• 기계와재료
• /
• v.16 no.3 s.61
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• pp.37-52
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• 2004

• Journal of Korea Foundry Society
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• v.12 no.1
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• pp.21-24
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• 1992

• 기계와재료
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• v.12 no.1 s.43
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• pp.65-74
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• 2000

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.15-15
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.389-389
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• 2011

최근 생체분자 구조 연구가 의료진단, 생명 현상 규명 및 의약품 개발 등 다양한 분야에 응용되고 있으나 대부분의 분석방법이 제한적이어서 새로운 기술 개발의 필요성이 증대하고 있다. 종래의 DNA 등의 생체분자의 분석은 형광염료를 이용한 방법이 주로 이용되었다. 형광염료는 단백질을 포함한 여러 물질들에 대해 반응하지 않기 때문에 분석에 제한이 있으며, 이와 같은 단점을 보완하는 방법으로 SPR (surface plasmon resonance) 분석법이 연구되었다. SPR은 형광염료 분석에 필수적인 레이블링(labeling) 등의 전처리 과정 없이 높은 민감도로 분석이 가능한 장점이 있다. 한편, 그래핀은 뛰어난 전자기적 성질과 기계적 성질 을 가지는 반금속(semimetal)으로, 실험실 규모에서 안정적인 합성이 실현되면서 그 응용 분야에 대한 연구가 활발히 이루어 지고 있다. 그래핀은 큰 표면적 대 부피비를 가지며, 이는 검출물질과의 반응성이 좋아야 하는 센서기술에 있어서 장점으로 작용한다. 특히, 비금속성을 띠는 단층 그래핀을 여러 장 겹치면 금속성을 갖게 되기 때문에 SPR 센서의 금속 필름으로 응용이 가능하다. 본 연구에서는 SPR 현상을 이용하는 광섬유 센서의 감도와 정확도를 증진시키기 위해 광섬유 표면에 그래핀을 적용하였다. 광섬유는 상부 피복과 클래딩을 제거하여 코어를 노출시킨 후, 다층 그래핀 필름을 코팅함으로써 검출부를 구성한다. 그 후, DNA-biotin 용액, DNA-biotin 용액, 그리고 Streptavidin 단백질 복합 용액에 대한 검출기 신호를 분석하였다. 구성된 센서에 각 용액을 1 ${\mu}{\ell}$ 씩 반응시켜 분광계로 파장에 따른 광강도를 측정하는 실험을 수행했으며, 450 nm에서 460 nm 범위의 푸른빛의 광원을 사용하였다. 그래핀 필름의 유무에 따라 확연히 구분되는 경향을 보이는 결과를 얻었고 그래핀 필름이 기존 SPR 센서의 금속박막을 대체 할 수 있음을 확인하였다.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.3
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• pp.557-565
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• 1997

Screw-shaped implants of commercially pure (c.p.) titanium, c.p. niobium, c.p. zirconium, and stainless steel(Sus 304) were inserted in the rabbit tibial bone over 12 weeks of follow-up. New developed torque gauge instrument was used to evaluate the implant holding power and a image analysis program coupled to a microscope was used for histomorphometry. The three best consecutive threads of each implant were measured. Quantitative analyses at 12 weeks revealed a partial bone contact to the four kinds investigated metals. There were no obvious adverse tissue reactions to any of the biomaterials. At 12 weeks the average removal torques for titanium, niobium and zirconium were better than that needed for Sus 304 screws, on the other hand high score of bony contact ratio of titanium and niobium were showed in comparison to those of zirconium and Sus 304. There was no significant differences in the amount of interfacial bone of zirconium and Sus 304 whereas there was significant difference in the torque forces of niobium and Sus 304. Three months after implant insertion, the average removal torque was 6.64 Ncm for the titanium, 6.57 Ncm for the niobium, 6.38 Ncm for the zirconium, and 4.25 Ncm for the Sus 304. On average bone contacts there were 51.24% in the titanium, 48.19% in the niobium, 31.79% in the zirconium, 23.54% in the Sus 304. Biocompatibility of the titanium, niobium and zirconium was acceptable level in comparison to the Sus 304.

• Korean Journal of Metals and Materials
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• v.46 no.10
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• pp.691-699
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• 2008

Electrochemical characteristics of Ti-30Ta-xZr alloys coated with HA/TiN by using magnetron sputtering method were studied. The Ti-30Ta containing Zr(3, 7, 10 and 15wt%) were 10 times melted to improve chemical homogeneity by using a vacuum furnace and then homogenized for 24hrs at $1000^{\circ}C$. The specimens were cut and polished for corrosion test and coating, and then coated with HA/TiN, respectively, by using DC and RF-magnetron sputtering method. The analyses of coated surface and coated layer were carried out by using optical microscope(OM), field emission scanning electron microscope(FE-SEM) and X-ray diffractometer(XRD). The electrochemical characteristics were examined using potentiodynamic (-1,500 mV~ + 2,000 mV) and A.C. impedance spectroscopy(100 kHz ~ 10 mHz) in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The microstructure of homogenized Ti-30Ta-xZr alloys showed needle-like structure. In case of homogenized Ti-30Ta-xZr alloys, a-peak was increased with increasing Zr content. The thickness of TiN and HA coated layer showed 400 nm and 100 nm, respectively. The corrosion resistance of HA/TiN-coated Ti-30Ta-xZr alloys were higher than that of the non-coated Ti-30TaxZr alloys, whic hindicate better protective effect. The polarization resistance($R_p$) value of HA/TiN coated Ti-30Ta-xZr alloys showed $8.40{\times}10^5{\Omega}cm^2$ which was higher than that of non-coated Ti-30Ta-xZr alloys.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.288-295
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• 2010

Metal exposure experiments using polychaete (Perinereis nuntia) as a bio-indicator of trace metals contamination were conducted to evaluate the bioaccumulation and the biomarkers responses such as metallothionein-like protein (MTLPs) and glutathione S-transferase (GST) which was simultaneously exposed to Cadmium (Cd) and Copper (Cu). Cu and Cd concentrations in polychaete were enhanced with increasing exposure time and their concentrations of aqueous medium. Initial accumulation of Cd was higher than that of Cu. Our results showed that the bioaccumulation of Cu and Cd were prohibited, especially at higher Cu levels, suggesting the different cellular uptake mechanisms when Cu and Cd are co-exist. Net accumulation rate of Cu was declined with exposure time but it did not show any significant change for Cd. Although the highest MTLPs concentration was observed at 6 hr of exposure time, it did not show any significant change related to exposure times and metals concentrations. An increase of GST activity tended to increase as a function of exposure time and metals concentrations. And GST activities in P. nuntia have similar tendency with bioconcentration factors in high concentration of Cu (treatment group IV) at post 24 h of exposure. Our results provide new information of the bioaccumulation and biomarker responses to understand the effects of co-existing contaminants (Cu and Cd) using polychaete. Further studies are required to elucidate the bioaccumulation and biomarkers responses for various contaminants.