• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.427-427
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• 2013

잉크젯 프린팅 방법은 전도성 고분자 물질을 잉크 재료로 사용하여 전자 소자의 전극 패턴을 형성할 수 있으며 비접촉, drop-on-demand 공정으로 현재 많은 관심을 받고 있는 연구 분야이다. Ag는 $1.59{\mu}m{\cdot}cm$의 저항을 나타내는 가장 낮은 저항을 가지고 있는 물질 중의 하나이며, Ag 전도성 잉크는 고전도 패턴의 형성을 위해 현재 많이 사용되고 있는 물질이다. 본 연구에서는 a-IGZO 박막을 채널층으로 사용하여 Ag S/D 전극을 잉크젯 프린팅 방법으로 형성하여 산화물 트랜지스터를 제작하였다. a-IGZO 채널층은 $SiO_2$가 증착된 Si 기판위에 스퍼터링 방식으로 80 nm의 두께로 형성하였다. Ag S/D 전극은 10 pl의 카트리지가 장착된 Fujifilm Dimatix DMP 2800 장비를 사용하여 형성하였으며, 프린팅 후 $130^{\circ}C$로 20분간 열처리를 하였다. Fig. 1은 잉크젯 프린팅된 Ag S/D을 가진 a-IGZO의 트랜지스터 특성을 보여준다. 채널 W/L가 90/$50{\mu}m$ 구간에서 드레인 전압이 50 V 일때, 전계효과이동도 $0.27cm^2$/Vs, 문턱전압 6.03 V, 문턱전압 아래의 기울기 값은 2.06 V/dec를 얻었다. 이와 같은 특성은 잉크젯 프린팅 방법으로 Ag S/D 전극을 형성함으로써 산화물 TFT에서 잉크젯 프린팅 방식의 다양한 응용 가능성을 확인할 수 있었다.

• Journal of Oral Medicine and Pain
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• v.7 no.1
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• pp.66-70
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• 1982

Medical personnek are one of several groups that have been reported to have a high incidence of hepatiris B. It is also thought that the occurrence rate of hepatitis B surface antigen(HBsAg), aserologic marker for hepatitis B virus(HBV), is expected to be high in the dental personnel who are frequently exposed to the blood and saliva of the patients. Although many studies have been done to determine the HBsAg status of virus groups, limited investigations have been performed on dental personnel, especially in this country. The main purpose of this study was to identify HBsAg positivity among dental students, interns, and residents who would be expected to be a high risk group of hepatitis B infection. Screening test for HBsAg of a dental school population was performed by indirect hemagglutination(IHA)in 1982. The results were as follows : 1. Thirty four out of a total 362 persons(9.4%)tested in the study had positive response for HBsAg in their serum samples. 2. Twenty seven out of 320 dental students(8.4%)had positive for HBsAg, and in Senior class 12 out of 82 dental students (14.6%)had positive response that was the highest incidence among dental students group. 3. Seven out of 42 interns and residents(16.7%)had positive for HBsAg, and it was the highest incidence in this dental school population.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.133-136
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• 2009

A newly designed Ag/$Ag^+$ reference electrode in a quartz tube with a tungsten tip junction (W-tip-Quartz- REF) was fabricated and its electrochemical performance was compared with a conventional Pyrex tube-based Ag/$Ag^+$ reference electrode (Py-REF). The results of the electrochemical potential measurements with the W-tip-Quartz- REF and the Py-REF in the LiCl-KCl eutectic melts for a wide temperature range proved that the oxide layer on the surface of the tungsten metal tip provided a high ionic conduction. Stability of our newly designed W-tip- Quartz-REF was tested by measuring a junction potential for 12 hours at 700${^{\circ}C}$. The results of the cyclic voltammetric measurement indicated that the Ag/$Ag^+$ reference electrode in the quartz tube with a tungsten tip junction can provide a good performance for a wide temperature range.

• Bulletin of the Korean Chemical Society
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• v.10 no.3
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• pp.230-234
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• 1989

The crystal structure of $Ag^+$-exchanged zeolite A vacuum-dehydrated at $370^{\circ}C$ and then treated with carbon monoxide at $$23^{\circ}C$ has been determined by single crystal x-ray diffraction methods in the cubic space group Pm3m at $23^(1){\circ}C$ ; a = 12.116 (2)${\AA}$. The structure was refined to the final error indices $R_1\;=\;0.061\;and\;R_2$(weighted) = 0.068 using 349 independent reflections for which I > 3${\sigma}(I).\;3.6\;Ag_+-CO$ complexes, where -CO may represent -CHO or -$CH_2OH$, were found in each large cavity. By coordination to silver atoms followed by reaction with $Ag^{\circ}and\;H^+$ within the zeolite, carbon monoxide has been partially reduced. In about 28% of the sodalite units, a $Ag_6(Ag^+)_2$ cluster may be present. In about 37% of the sodalite units, three $Ag^+$ ions are found on threefold axes where they may be bridged by three water molecules. The remaining 35% of the sodalite units are empty of silver species. Two $Ag^+$ ions per unit cell are associated with 8-ring oxygens. The remaining ca $$3Ag^+$ ions per unit cell have been reduced during the synthesis and have migrated to form small silver crystallities on the surface of the zeolite single crystal.

• Advances in nano research
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• v.10 no.2
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• pp.139-150
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• 2021

In this study, phytochemicals present in Propolis Extract (PE) were employed as reducing and stabilizing reagents to synthesize silver nanoparticles. Three propolis-reduced silver nanoparticles (P-AgNPs1-3) were synthesized using increasing amounts of PE. P-AgNPs were treated with different cancer cells-lung (A549), cervix (HeLa) and colon (WiDr) - for 24, 48 and 72 h to evaluate their anti-proliferative activities. A non-cancerous cell type (L929) was also used to test whether suppressive effects of P-AgNPs on cancer cell proliferation were due to a general cytotoxic effect. The characterization results showed that the bioactive contents in propolis successfully induced particle formation. As the amount of PE increased, the particle size decreased; however, the size distribution range expanded. The antioxidant capacity of the particles increased with increased propolis amounts. P-AgNP1 exhibited almost equal inhibitory effects across all cancer cell types; however, P-AgNP2 was more effective on HeLa cells. P-AgNPs3 showed greater inhibitory effects in almost all cancer cells compared to other NPs and pure propolis. Consequently, the biological effects of P-AgNPs were highly dependent on PE amount, NP concentration, and cell type. These results suggest that AgNPs synthesized utilizing propolis phytochemicals might serve as anti-cancer agents, providing greater efficacy against cancer cells.

• Korean Journal of Materials Research
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• v.32 no.1
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• pp.51-55
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• 2022

Generally, Au electrodes are the preferred top metal electrodes in most perovskite solar cells (PSCs) because of their appropriate work function for hole transportation and their resistance to metal-halide formation. However, for the commercialization of PSCs, the development of alternative metal electrodes for Au is essential to decrease their fabrication cost. Ag electrodes are considered one of the most suitable alternatives for Au electrodes because they are relatively cheaper and can provide the necessary stability for oxidation. However, Ag electrodes require an aging-induced recovery process and react with halides from perovskite layers. Herein, we propose a bilayer Au/Ag electrode to overcome the limitations of single Au and Ag metal electrodes. The performance of PSCs based on bilayer electrodes is comparable to that of PSCs with Au electrodes. Furthermore, by using the bilayer electrode, we can eliminate the aging process, normally an essential process for Ag electrodes. This study not only demonstrates an effective method to substitute for expensive Au electrodes but also provides a possibility to overcome the limitations of Ag electrodes.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.60-64
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• 2012

Silver(I) [bis(alkylthio)methylene]malonates were synthesized from the reaction of silver nitrate and potassium [bis(alkylthio)methylene]malonates. The structures of the Ag complexes were characterized with nuclear magnetic resonance (NMR), inductively coupled plasma atomic emission spectrometry (ICP-AES) and elemental analysis. Ag nanoparticles (NPs) were obtained from the decomposition of the Ag complexes in 1,2-dichlorobenzene at $110^{\circ}C$ without an additional surfactant. The average sizes of the Ag NPs are in the range of 5.1-6.3 nm and could be controlled by varying the length of the alkyl chain. The optical properties, crystalline structure and surface composition of Ag NPs were characterized with ultraviolet-visible (UV-visible) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), gas chromatography-mass spectrometry (GC-MS), X-ray Photoelectron Spectroscopy (XPS) and thermal gravimetric analysis (TGA).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.120-122
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• 1994

We examined the magnetic properties as a function of annealing temperature of the as-quenched $Fe_{87}Zr_{7}B_{5}Ag_{1}$ amorphous alloy. The values of $H_{c}$=30m0e, $B_{a}$=0.44T and ${\mu}$i=146000 at $300^{\circ}C$ annealing treatment are obtained. The excel lent soft magnetic properties seem to result from the annihilation of quenching-Induced internal stress by the heat treatment and the change of microstructure due to the different relaxation behavior owing to adding insoluble element such as Ag. Therefore, the $Fe_{87}Zr_{7}B_{5}Ag_{1}$ amorphous alloy is quite promising for practical use as a core material in various transformers of high transformers of high frequency.

• The Korea Journal of Herbology
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• v.28 no.5
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• pp.113-119
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• 2013

Objectives : The purpose of this study was to investigate the effects of Angelicae Gigantis Radix Water Extract(AG) on the production of proinflammatory mediators in RAW 264.7 cells stimulated with lipopolysaccharide(LPS). Method : RAW 264.7 cells were cotreated with AG(50 and 100 ug/mL) and lipopolysaccharide(LPS; 1 ug/mL) for 24 hours. After 24 hour treatment, using Bead-based multiplex cytokine assay, concentrations of various cytokines such as interleukin(IL)-6, IL-$1{\beta}$, IL-10, tumor necrosis factor-alpha(TNF-${\alpha}$), granulocyte colony-stimulating factor(G-CSF), granulocyte macrophage colony-stimulating factor(GM-CSF), interferon inducible protein-10(IP-10), leukemia inhibitory factor(LIF), lipopolysaccharide-induced chemokine(LIX), monocyte chemoattractant protein-1(MCP-1), macrophage colony-stimulating factor(M-CSF), macrophage inflammatory protein(MIP)-$1{\alpha}$, MIP-$1{\beta}$, MIP-2, Regulated on Activation, Normal T cell Expressed and Secreted(RANTES) and vascular endothelial growth factor(VEGF) were measured. Result : AG significantly inhibited LPS-induced production of TNF-${\alpha}$, MIP-$1{\alpha}$, G-CSF, RANTES, IL-10, and M-CSF from LPS-stimulated RAW 264.7 cells at the concentrations of 50 and 100 ug/mL. AG significantly inhibited LPS-induced production of MIP-$1{\beta}$, MIP-2, GM-CSF, and IL-6 from LPS-stimulated RAW 264.7 cells at the concentrations of 50 ug/mL. AG significantly inhibited LPS-induced production of VEGF from LPS-stimulated RAW 264.7 cells at the concentrations of 100 ug/mL. But AG did not show any significant effect on the production of MCP-1, LIF, LIX, IP-10 and IL-$1{\beta}$ from LPS-induced RAW 264.7 cells. Conclusion : These results suggest that AG has anti-inflammatory effect related with its inhibition of proinflammatory mediators such as TNF-${\alpha}$, MIP-$1{\alpha}$, G-CSF, RANTES, IL-10, MIP-$1{\beta}$, MIP-2, GM-CSF, IL-6, VEGF and M-CSF in LPS-induced macrophages.

• Transactions on Electrical and Electronic Materials
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• v.14 no.1
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• pp.9-11
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• 2013

The AZO/Ag/AZO multilayer films were deposited on polyethersulfone (PES) substrate by using facing target sputtering methods at room temperature. The AZO/Ag/AZO multilayer films with polymer substrate had advantages, such as low sheet resistance, high optical transmittance in visible range and stable mechanical properties. From the results, the AZO/Ag/AZO multilayer films (50/12/50 nm) demonstrated a sheet resistance of 11 ${\Omega}/{\square}$ and average transmittance of 87% in visible range (wavelength of 380-770 nm). Moreover, the multilayer showed stable mechanical properties compared to the single-layered AZO sample during the bending test due to the existence of the ductile Ag metal layer.