• Korean Journal of Materials Research
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• v.4 no.5
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• pp.556-565
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• 1994

Effects of Ag addition to 2090 and CP 276 Al-Li alloy systems on the microstructure and mechanical properties have been investigated. The addition of silver up to 0.16wt.% reduced the grain size of the alloys, and was responsible for the formation of finer and more uniform $\delta$'($AI_{3}Li$) and $T_{1}(AI_{2}CuLi$) precipitates in 2090 alloys, even though no variation of precipitates was found in CP 276 alloys. The addition of 0.16wt.% Ag improved the tensile strength of 2090 alloys about 40MPa with the expense of small reduction of percent elongation. However, the small addition of Ag to CP 276 containing Mg did not show any variation of tensile strength and elongation. The aging treatment of these alloys at $150^{\circ}C$ for 70 or 90 hours, depending on alloy systems, showed peak hardness value of about 92 $H_rB$.

• Journal of Powder Materials
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• v.18 no.2
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• pp.159-167
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• 2011

The influence of sulfate on the selective catalytic reduction of $NO_x$ on the Ag/$Al_2O_3$ catalyst was studied when $CH_4$ was used as a reducing agent. Various preparation methods influenced differently on the $deNO_x$ activity. Among the methods, cogelation precipitation gave best activity. When sulfates were formed on the surfaces of samples prepared by impregnated and deposition precipitation, $deNO_x$ activity was enhanced as long as suitable forming condition is satisfied. The major sulfate formed in Ag/$Al_2O_3$ catalyst was the aluminum sulfate and it seems that this sulfate acted as a promoter. When Mg was added to the Ag/$Al_2O_3$ catalyst it promoted $deNO_x$ activity at high temperature. Intentionally added sulfate also enhanced $deNO_x$ activity, when their amount was confined less than 3 wt%.

• Carbon letters
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• v.2 no.3_4
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• pp.159-164
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• 2001

In this study, the effects of carbon black (CB) content and anodic oxidation treatment with $AgNO_3$ on positive temperature coefficient (PTC) behavior of CB/HDPE nanocomposites were investigated. Also, the addition of elastomer as a toughing agent was studied. The 20~50 wt% of CB, 0~5 wtt% of elastomer, and 1 wt% of $AgNO_3$-filled HDPE nanocomposites were prepared using the internal mixer in 60 rpm at $160{\circ}C$ and the compression-molded at $180{\circ}C$ for 10 min. As a result, the room temperature resistivity and PTC intensity of the composites were dependent, to a large extent, on the content of CB, addition of elastomer, and surface chemical properties that were controlled in the relative arrangements of the carbon black aggregates in a polymeric matrix. Moreover, the composites with relatively low room temperature resistivity and suitable PTC intensity could be achieved by treatment of $AgNO_3$. Consequently, it was noted that PTC effect was due to the deagglomeration or the breakage of the conductive networks caused by thermal expansion or crystalline melting of the polymeric matrix.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.253-262
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• 1981

The AgI/ PV${\cdot}$THF membrane electrode could be used as an indicator electrode in the potentiometric titration of single halide and mixture halide solutions with the standard solution of silver nitrate. The errors in the stepwise titrations of mixture halide solutions were considerably large, but by addition of flocculating agent, such as $NaNO_3$ or $Ba(NO_3)_2$, in the sample solution, the errors were greatly reduced. Also, the effects of gelatin, filter paper and temperature on the titration errors were examined.

• Journal of Plant Biotechnology
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• v.36 no.2
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• pp.137-143
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• 2009

An efficient system for high frequency plant regeneration was established through investigating various factors such as plant growth regulator combinations, explant types and ages, and addition of $AgNO_3$ influenced on shoot regeneration in Brassica juncea L. cv. BARI sarisha-10. Murashige and Skoog (MS) medium supplemented with 0.1 mg/L NAA (1-naphthaleneacetic acid) and 1 mg/L BA (6-benzyladenine) showed the maximum shoot regeneration frequency (56.67%) among the different combinations of NAA and BA. Explant type, explant age, and addition of $AgNO_3$ also significantly affected shoot regeneration. Of the four type of explants (cotyledon, hypocotyl, root, and leaf explants)- cotyledon explants produced the highest shoot regeneration frequency and hypocotyls explants produced the highest number of shoots per explant, whereas root explants did not produce any shoot. The cotyledonary explants from Four-day-old seedlings showed the maximum shoot regeneration frequency and number of shoots per explant. Shoot regeneration frequency increased significantly by adding $AgNO_3$ to the medium. Two mg/L $AgNO_3$ appeared to be the best for shoot regeneration with the highest shoot regeneration frequency (86.67%) and number of shoots per explant (7.5 shoots). Considerable variation in shoot regeneration from cotyledonay explants was observed within the B. juncea L. genotypes. The shoot regeneration frequency ranged from 47.78% for cv. Shambol to 91.11% for cv. Rai-5. In terms of the number of shoots produced per explant, B. juncea L. cv. Daulot showed the maximum efficiency. MS medium supplemented with 0.1 mg/L NAA showed the highest frequency of rooting. The regenerated plantlets were transferred to pot soil and grown to maturity in the greenhouse. All plants were fertile and morphologically identical with the source plants.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2592-2596
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• 2012

Cysteine capped silver nanoparticles (Cys-AgNPs) have been synthesized by employing electrochemically active biofilm (EAB), $AgNO_3$ as precursor and sodium acetate as electron donor in aqueous solution at $30^{\circ}C$. Cys-AgNPs of 5-10 nm were synthesized and characterized by UV-Vis, FT-IR, XRD and TEM. Capping of the silver nanoparticles with cysteine provides stability to nanoparticles by a thiolate bond between the amino acid and the nanoparticle surface and hydrogen bonding among the Cys-AgNPs. In addition, the antibacterial effects of as-synthesized Cys-AgNPs have been tested against two pathogenic bacteria Escherichia coli (O157:H7) and Pseudomonas aeruginosa (PAO1). The results demonstrate that the as-synthesized Cys-AgNPs can proficiently inhibit the growth and multiplication of E. coli and P. aeruginosa.

• Biomedical Science Letters
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• v.24 no.1
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• pp.30-34
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• 2018

Silver (Ag) has been widely used in commercial products and medical fields since ancient times because of its antibacterial effect. It is harmless and non-toxic to the human body. For this reason, recent research has actively evaluated antimicrobial activity using silver (Ag). In this study, we investigated the inhibitory effect of a silver-based compound, silver phosphate ($Ag_3PO_4$) on the growth of Staphylococcus aureus and the activation of human immunity. First, the inhibitory effect of $Ag_3PO_4$ on the growth of Staphylococcus aureus was confirmed by a growth curve and a colonyounting method. As a result, the growth inhibitory effect increased as the concentration of $Ag_3PO_4$ increased. Specifically, treatment with $5{\mu}g/mL$ of $Ag_3PO_4$ resulted in no bacteria growth, and the colony-counting method showed a remarkable inhibition. In addition, the expression of cytokine IL-8 by $Ag_3PO_4$ was examined to investigate the cellular immune system activation by $Ag_3PO_4$. After pretreatment of Staphylococcus aureus for 1 hour with $50{\mu}g/mL$ $Ag_3PO_4$, an increased IL-8 mRNA expression resulted. In cells treated with $Ag_3PO_4$, we found that the expression of IL-8 was enhanced in a time-dependent fashion compared to non-treated cells. These results indicate that $Ag_3PO_4$ induces antimicrobial activity against Staphylococcus aureus and activates human immunity. These results are expected to contribute to the future study of the mechanism of silver (Ag) and silver-based compounds in relation to antibacterial activity.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.140-140
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• 2000

The initial growth mode of Nb on Ag(11) in sub-monolayer regime and the influence of subsequent 520K annealing are studied using UHV Scanning Tunneling Microscopy. E-beam evaporated Nb is deposited onto the substrate at RT, and STM measurements are carried out at RT and 78 K. With Nb being immiscible in bulk Ag, 3D islands formation begins at early stage and no particular ordered structure is found. After annealing to 520K, most of islands are disappeared from terrace. There exist 2 possibilities. : (1) Diffusion of Nb into the 2nd or 3rd layer of Ag substrate or (2) agglomeration of Nb on Ag at higher temperature. A model will be given to explain the evidence. In addition, we investigated the change of STM image according to bias voltage depending on island size. Possible physical mechanism responsible for such behavior together with interaction between Nb islands and reactive gases will be also discussed.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.49-52
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• 1997

The effects of several additives on plant regeneration were investigated from leaf disc culture of S. tuberosum cv. Atlantic which is known as poor in regeneration ability. The presence of 2 g/L casein hydrolysate significantly enhanced shoot regeneration. Addition of 10~20 $\mu$M $AgNO_3$, not only increased the frequency of shoot regeneration but also maintained the leaf disc green presumably by the inhibitory action of ethylene accumulation in vitro. Decrease of sucrose levels to below 3% significantly increased the degree of regeneration. The addition of CuSO$_4$had no effect on shoot regeneration.

• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1074-1082
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• 2002

Nanocomposite PMN-PT-BT/Ag/MgO was prepared by sintering at $950{\circ}C$ with addition of $AgNO_3$ and MgO sol to the PMN-PT-BT powder sinterable at $1200{\circ}C$. The low-temperature-sinterable PMN-PT-BT/Ag powder prepared by the modified mixed oxide method was calcined at $600{\circ}C$ for 1h and surface modified with the MgO sol of 0-10 wt% and then subjected to consolidation at $850-950{\circ}C$ for 4h under a flowing oxygen. The nanocomposite PMN-PT-BT/Ag/MgO(0.5wt%) sintered at $950{\circ}C$ showed the microstructure with grains of $1-3{\mu}m$, the second phase of MgO of $0.1-0.3{\mu}m$ by SEM and Ag of << $1{\mu}m$ qualitatively by SIMS. It showed the sintered relative density of 99%, the room temperature dielectric constant of 17200, the dielectric loss of 2.1% and the specific resistivity of $5.46{\times}10^{12}{\Omega}{\cdot}cm$. But the PMN-PT-BT/Ag/MgO(0 wt%) nanocomposite sintered at $950{\circ}C$ showed a little better properties : the sintered relative density of 99.5%, the room temperature dielectric constant of 19500, the dielectric loss of 2.1% and the specific resistivity of $7.30{\times}10^{12}{\Omega}{\cdot}cm$.