• Title/Summary/Keyword: Ag%24_2%24O

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Evaluate the Suitability of MC3T3 Cells to Antibacterial Ag-30CaO·70SiO2 Gel (항균성 Ag-30CaO·70SiO2 Gel의 MC3T3 세포적합성에 관한 연구)

  • Yoon, Geum-Jae;Ryu, Jae-Kyung;An, Eung-Mo;Kim, Yun-Jong;Kim, Taik-Nam;Noh, In-Sup;Cho, Sung-Beck
    • Korean Journal of Materials Research
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    • v.24 no.12
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    • pp.671-676
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    • 2014
  • It is known that bones get damaged by accidents and aging. Since the discovery of Bioglass, various kinds of ceramics have been also found to bond to living bone; some of these ceramics are already being clinically used as bone-repairing materials. In the present study, antibacterial calcium silicate gel ($Ag-30CaO{\cdot}70SiO_2$ gel) was prepared by sol-gel method in order to control the microstructure, which is related to the dissolution rate and induction period of apatite formation in body environment. In addition, biological $Ag-30CaO{\cdot}70SiO_2$ is tested. This was done to impart antimicrobial activity to the $30CaO{\cdot}70SiO_2$. Ag ion was added during sol-gel synthesis to replace the $H_2O$ added during the making of the $30CaO{\cdot}70SiO_2$ gel, which has silver solutions of various concentration. After the sol-gel process, 1N-$HNO_3$ solution was used to wash the gel when synthesizing the gel, in order to maintain the porous structure and remove PEG, water soluble polymers. Then, the apatite forming ability of the sol-gel derived CaO-$SiO_2$ gels was investigated using simulated body fluid (SBF), which had almost the same ion concentration as that of human blood plasma. The gels were analyzed by FT-IR spectroscopy, SEM observation, XRD, and fluorescent microscopy. The apatite was successfully created even after washing the gel; apatite is present in an amorphous state, and was found to affect the concentration of the Ag ion in cells in MC3T3 live & dead assay results. From these results, it is suggested that a good material that can be used to repair defects of nature bone is $Ag-30CaO{\cdot}70SiO_2$ gel.

Preparation of Ag/TiO2 Particle for Aerobic Benzyl Alcohol Oxidation (Aerobic Benzyl Alcohol Oxidation 반응용 Ag/TiO2 제조)

  • Kim, Chang-Soo;Yoo, Kye Sang
    • Applied Chemistry for Engineering
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    • v.24 no.6
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    • pp.663-667
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    • 2013
  • $Ag/TiO_2$ particle was prepared using various ionic liquids by wet impregnation. The properties of the particles were significantly affected by the composition of ionic liquids. This is mainly attributed to different abilities of an ionic liquid to coordinate with the silver particle, leading to various coagulation of silver particles. The catalytic activity of the prepared samples was examined for the aerobic benzyl alcohol oxidation. Among the particles, $Ag/TiO_2$ prepared with 1-octyl-3-methylimidazolium tetrafluoroborate showed the best catalytic performance.

Genotoxicity Studies of the Complex of Acriflavine and Guanosine (Acriflavine과 Guanosine 복합체(AG60)의 유전독성시험)

  • 정영신;홍은경;김상건;안의태;이경영;강종구
    • Environmental Mutagens and Carcinogens
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    • v.22 no.2
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    • pp.106-111
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    • 2002
  • AG6O, the complex of acriflavine and guanosine, has been shown to possess the synergistic antitumorigenic activity in the previous paper (J. Pharm. Pharmacol. 1997, 49:216). In this study, we have investigated the genotoxic properties of AG60 using in vitro and in vivo system such as Ames bacterial reversion test, chromosomal aberration assay and micronucleus assay. In Ames reverse mutation test, AG60 treatment at the dose range up to 250 $\mu\textrm{g}$/plate caused the dose-independent random induction of the mutagenic colony formation in S. typhimurium TA98, TA100, TA1537, and E. coli WP2uvrA, while any mutagenic effect of AG60 wasn't observed in S. typhimurium TA1535. Any significant chromosomal aberration wasn't observed in chinese hamster lung (CHL) fibroblast cells incubated with PBS or AG60 at the concentrations of 2.5, 5, 10 $\mu\textrm{g}$/$m\ell$ for 24 hours without but even with 59 metabolic activation system for 6 hours. In vivo ICR mice, the intramuscular injection of AG60 at the doses of 7.15, 14.3, and 28.6 mg/kg did not induce the frequency of micronucleus formation. However, mitomycin C, as one of the positive controls at the dose of 2 mg/kg caused the 8.4% induction in the frequency of micronucleus and 24% increase in the chromosomal aberration.

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Effect of Nano Particles on Fertilized Egg of Crossostrea gigas (참굴(Crassostrea gigas) 수정란에 미치는 나노입자의 영향)

  • Lee, Byeong-Woo;Park, Chan-Il;Choi, Kwang-Soo;Kim, Mu-Chan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.14 no.1
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    • pp.9-14
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    • 2008
  • A Nano particle is a small particle with at least one dimension less than 100 nm Nanoparticle is currently used in an area cf intense scientific research, due to a wide variety cf potential applications in biomedical, optical, and electronic fields. In order to know the biological effect of the nine Nano particles on fertilized egg of Crassostrea gigas experiments were performed Development rates of control (free Nano particles) C. gigas to a particular larval stage (D-shape) was 78%. Development rate of C gigas to a parcicular larval stage (D-shape) after 24 hours exposure to 0.05ppm of AGZ020, Nano silver, P-25 and SnO were 22%, 52%, 58% and 76%, respectively. However, all fertilized eggs were destructed within 8 hours afters exposure to 20ppm of respective particles. On the other hand, All fertilized eggs were not affected after 24 hours respective exposure to 0.05ppm of In, Sb, Sn, Zn, and Ag-$TiO_2$ particles. However, development rates of C. gigas after 24 hours exposure to 20ppm of In, Sb, Sn, Zn, Ag-$TiO_2$ were 57%, 60%, 50%, 65%, and 64% respectively.

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고온초전도 BSCCO 2223상 형성시 나타나는 여러 가지 이차상들이 선재의 임계전류에 미치는 영향(토요일)

  • 박성창;김철진;유재무;고재웅;김영국
    • Proceedings of the Korea Crystallographic Association Conference
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    • 2003.05a
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    • pp.24-24
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    • 2003
  • 고온초전도 BSCCO 2223 ((Bi, Pb)₂Sr₂Ca₂Cu₃O/sub x/) 선재의 특성을 향상시키기 위해서는 반복적인 인발 및 압연과정을 통한 texturing향상, BSCCO 2223입자의 배향성 증대, 피복재내 초전도체의 충진율(밀도)향상, 이차상의 부피분율 감소등이 이루어져야 한다. 최적 열처리 조건을 통하여 열처리 시에 형성되는 이차상인 (Bi,Pb)₂Sr₂CuO/sub y/ (2201, amorphous phase)를 조절하면서, (Ca,Sr)₂CuO₃ (2/1 AEC), (Ca,Sr)/sub 14/Cu/sub 24/O/sub 41/ (14/24 AEC)와 같은 이차상들의 부피분율 및 크기를 감소시켜야만 한다. 본 실험에서는 BSCCO 2223 선재의 특성을 향상시킬수 있는 최적의 열처리 조건 확립 및 기계적 공정시 나타나는 여러 가지 문제점을 개선하여 높은 임계전류를 가지는 선재의 특성을 분석하고자 하였다. 최종적으로 제조된 선재는 2223상 결정이 피복재(Ag)와 평행하게 길게 성장하며, AEC상의 크기와 부피분율이 감소할수록 더 높은 임계전류특성을 나타내었다(I/sub c/~70A, J/sub c/~42,000 A/㎠). 또한 이 선재에서 나타나는 여러 가지 이차상들을 분석하기 위하여 XRD, SEM, EDS 분석을 행하였다.

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Synthesis of Metal Oxide-Coated Conductive Metal Powders and Their Application to Front Electrodes for Solar Cells (산화물이 코팅된 전도성 금속 분말의 제조 및 태양전지 전면 전극으로의 응용)

  • Park, Jin Gyeong;Lee, Young-In
    • Korean Journal of Materials Research
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    • v.24 no.9
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    • pp.502-507
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    • 2014
  • Recently, improvement in the conversion efficiency of silicon-based solar cells has been achieved by decreasing emitter doping concentration, because the lightly doped emitter can effectively prevent the recombination of electrons and holes generated by solar light irradiation. This type of emitter is very thin due to the low doping concentration, thus conductive materials (i.e., silver) used for front electrodes can easily penetrate the emitter during a firing process because of their large diffusivity in silicon. This results in junction leakage currents which might reduce cell efficiencies. In this study, $Al_2O_3$-coated Ag powders were synthesized by an ultrasonic spray pyrolysis method and applied to the conductive materials of the front electrode to control the junction leakage current. The $Al_2O_3$ shell obstructs the Ag diffusion into the emitter during the firing process. The powder is spherical with a core-shell structure and the thickness of the $Al_2O_3$ shell is tens of nanometers. Solar cells were fabricated using pure Ag powders or the $Al_2O_3$-coated Ag powder as front electrode materials, and the conversion efficiency and junction leakage current were compared to investigate the role of the $Al_2O_3$ shell during the firing processes.

Electrode Properties of Li-ion Batteries using $TiO_2$-based Composite Nanowires ($TiO_2$기반 복합 나노선을 이용한 리튬이온 배터리의 전극 특성 연구)

  • An, Geon-Hyoung;Ahn, Hyo-Jin
    • Journal of the Microelectronics and Packaging Society
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    • v.18 no.3
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    • pp.19-24
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    • 2011
  • we successfully synthesized $TiO_2$-Ag composite nanowires via an electrospinning method and investigated the relationship between their electrochemical properties and structures by means of field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cycler. It is shown that the $TiO_2$-Ag composite nanowires exhibit superior electrochemical properties when compared to the single $TiO_2$ nanowires and $TiO_2$ nanoparticles (P25, Degussa). Therefore, the results indicate that the introduction of Ag nanophases within the electrospun $TiO_2$ nanowires could be improved the capacitance and cycleability of electrodes in Li-ion batteries.

The Study of Glass Crystallization Mechanism Using Femtosecond Laser Pulse (극초단파레이저를 활용한 유리의 결정화 메커니즘 고찰)

  • Moon P.Y.;Yoon D.K.;Lee K.T.;Shin S.B.;Cho S.H.;Ryu B.K.
    • Transactions of Materials Processing
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    • v.15 no.3 s.84
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    • pp.213-219
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    • 2006
  • To improve the strength of glass is being studied in order to contribute to weight saving of flat panel displays. Generally, the strength achieved of glass-ceramics is higher as is the fracture toughness by the formation of a heterogeneous phase inside glass. In this study, Ag-doped $45SiO_2-24CaO-24Na_2O-4P_2O_5\;and\;70SiO_2-10CaO-24Na_2O-10TiO_2$ glasses were irradiated to strengthen by crystallization using femto-second laser pulse. XRD, Nano-indenter and SEM etc., irradiation of laser pulse without heat-treated samples was analyzed. Samples irradiated by laser had higher value($4.4{\sim}4.56^*10-3Pa$) of elastic modulus which related with strength of glass than values heat-treated samples and these are $1.2{\sim}1.5$ times higher values than them of mother glass. This process can be applicable to the strengthening of thinner glass plate, and it has an advantage over traditional heat-treatment and ion-exchange method.

Electrical Conductivity in oxide glasses subjected to a sodium silver ion-exchange treatment (산화물유리에서의 $Na^{+}$이온과 $Ag^{+}$이온 교환에 따른 전기전도도 변화에 관한 연구)

  • 한준수;강원호;이효경
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1995.05a
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    • pp.100-105
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    • 1995
  • Bulk glasses in the system $Na_2O$-CaO-$Al_2O_3$-$B_2O_3$-$SiO_2$ containing 20 to 30 mol% sod-ium hav been subjected to a sodium silver ion-exchange reaction for 0, 24, 36, 48 jr were analysed by electrical characterization Ion-exchanged glasses exhibit resistivity and activation energy values lower than those of the untreated ones. The electrical conductivity increase with sodium content and ion-exchanged time. In this experiment the electrical conductivity exhibit a maximum value of 1.78${\times}$10$^{-4}$S/cm at $200^{\circ}C$ which contains 30 mol% sodium and subjects ion-exchange reaction for 48hr.

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Effect of Nano Particles on the Hathcing rate of Artemia sp. Cyst Zooplankton (나노입자가 알테미아(Artemia sp.) Cyst 부화율에 미치는 영향)

  • Jeong, Yeon-Kyu;Lee, Byeong-Woo;Park, Chan-Il;Choi, Kwang-Soo;Kim, Mu-Chan
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.4
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    • pp.302-306
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    • 2009
  • 9 kinds of nanoparticle used for this study was a particle with the size of less than 100 nm of diameter, and Artemia sp. cyst examined what kind of influence to have upon the process hatched out in nauplius. 82% hatched in nauplius at the opposition ward where a nanoparticle wasn't added after 24 time course. AGZ020, Nano silver, P-25, Sb and SnO nanoparticle showed hatching rate of 18%, 20%, 13%, 50% and 0% respectively by the 20mg/L density, and it became clear that a harmful effect is big, but I had a harmful effect compared with the opposition ward by 75%, 60%, 73% and 73% respectively by Ag-$TiO_2$, In, Sn and Zn nanoparticle, but a feeble thing was known relatively compared with AGZ020, Nano silver, P-25, Sb and SnO nanoparticle. The difference has caused this with the ingredient a nanoparticle has. Ag is included 2 % and AGZ020, Nano silver and P-25 nanoparticle are used widely as anti-fungus agent, and the SnO nanoparticle which became combination is a light catalyst pill, and oxygen is used for a Sn particle. This and others, a possibility that use is generalized and flows into aquatic environment in sequence the home electronics, functionality cosmetics, anti-fungus agent and a light catalyst pill at present becomes high for nanoparticles and others. The anxiety which has an influence on the ecology world in the water with this can be generated, so I'd have to study the potential danger a nanoparticle has continuously.

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