• Korean Journal of Plant Resources
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• v.7 no.2
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• pp.133-135
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• 1994

Germination rate of encapsulated somatic embryos shelved significant differences under different concentrations of AgN03. The highest germination rate of 81.2% was found on MS medium withouthormones mixed with 10 mg/1 of AgN03. In vitro vermiculite planted with encapsulated embryostreated with 10 mg/1 of AgN03 induced 24.7% germination rate, and vermiculite planted with encap-sulated embryos treated with 40 mg/1 or 80 mg/1 of AgNO, induced no germination at all.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.97-97
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• 2017

This study investigated the corrosion protection by electrodeposited copper layer on AZ31 Mg alloy with and without additional silver layer by immersion test, salt spray test, OCP transient and potentiodynamic polarization experiment. The single electrodeposited Cu layer on AZ31 Mg alloy showed a nodular structure with many imperfections of crevices between the nodules, which resulted in the fast initiation of pitting corrosion within first few hours of immersion. Double-layer coating of Cu and outer Ag layer slightly increased the initiation time for pitting corrosion. Triple-layer coatings of Cu/Ag/Cu exhibited the most efficient corrosion protection of AZ31 Mg alloy, compared to the single- and double-layer coatings. Surface morphology of the outer Cu layer in the triple-layer was changed from the nodular structure to fine particle structure with no crevices due to the presence of an additional Ag layer. Thus, the improved corrosion resistance of AZ31 Mg alloy by electrodeposited Cu/Ag or Cu/Ag/Cu layers is readily ascribed to the decreased number of imperfections in the electrodeposited layers due to the additional silver layer. It is concluded that the additional silver layer provides many nucleation sites for the second Cu plating, resulting in the formation of finer and denser structure than the first Cu electrodeposit.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1429-1431
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• 2005

Organic molecular-beam deposition of Mg:Ag thin films with a low Mg concentration on tris (8-hydroxyquinolino) aluminum $(Alq_3)$ layers at room temperature was performed to investigate the feasibility of using Mg:Ag thin films as cathode electrodes in organic light-emitting devices (OLEDs). The effective barrier height of the $Mg:Ag/Alq_3$ heterointerface, determined from current-voltage measurements, was as low as 0.23 eV. These results help improve understanding the electrical properties of the $Mg:Ag/Alq_3$ heterointerfaces in OLEDs.

• Korean Journal of Materials Research
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• v.22 no.7
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• pp.329-334
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• 2012

Two types of nanoclusters, termed Cluster (1) and Cluster (2) here, both play an important role in the age-hardening behavior in Al-Mg-Si alloys. Small amounts of additions of Cu and Ag affect the formation of nanoclusters. Two exothermic peaks were clearly detected in differential scanning calorimetry(DSC) curves by means of peak separation by the Gaussian method in the base, Cu-added, Ag-added and Cu-Ag-added Al-Mg-Si alloys. The formation of nanoclusters in the initial stage of natural aging was suppressed in the Ag-added and Cu-Ag-added alloys, while the formation of nanoclusters was enhanced at an aging time longer than 259.2 ks(3 days) of natural aging with the addition Cu and Ag. The formation of nanoclusters while aging at $100^{\circ}C$ was accelerated in the Cu-added, Ag-added and Cu-Ag-added alloys due to the attractive interaction between the Cu and Ag atoms and the Mg atoms. The influence of additions of Cu and Ag on the clustering behavior during low-temperature aging was well characterized based on the interaction energies among solute atoms and on vacancies derived from the first-principle calculation of the full-potential Korrinaga-Kohn-Rostoker(FPKKR)-Green function method. The effects of low Cu and Ag additions on the formation of nanoclusters were also discussed based on the age-hardening phenomena.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.42-48
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• 2011

This experiment was conducted to improve postharvest quality and extended vase life of Korean native Aster koraiensis Nakai for use as cut flowers. Aster koraiensis Nakai cut flowers were treated with various pretreatment and holding solution. Postharvest pretreatment with 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3$ + $50mg{\cdot}L^{-1}$ BA and 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3$ + $150mg{\cdot}L^{-1}$ citric acid for 16 hours extended vase life of cut Aster koraiensis Nakai flowers by 1.4 times as compared with the control (distilled water). Holding solution of 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3$ + $50mg{\cdot}L^{-1}$ BA and 3% sucrose + $200mg{\cdot}L^{-1}$ HQC + $50mg{\cdot}L^{-1}\;AgNO_3$ + $150mg{\cdot}L^{-1}\;GA_3$ extended vase life of cut Aster koraiensis Nakai flowers by1.6 and 1.7 times as compared with control (distilled water). Aster koraiensis Nakai.flowers held in this preservative solution increased fresh weight and were maintained positive water balance for a long vase period. It was suggested that the vase life of cut Aster koraiensis Nakai flowers was closely related to fresh weight and water balance of the cut flower.

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.846-850
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• 2002

A PMN-PT-BT/Ag composite was prepared by surface modification with MgO sol with hoping to suppress silver's migration during sintering. The mixture of PbO, $N_2O_5,\;TiO_2\;with\;Mg(NO_3)_2$ instead of MgO was ball milled, the solvent was removed and then the dried powders were calcined at 950$^{\circ}C$/1h. The calcined powder were treated with 3.0 mol% $Ag_2O$ and 1.0 wt% MgO sol and calcined at 550$^{\circ}C$/1h. The dielectrics sintered at 1000$^{\circ}C$/4h under a flowing oxygen showed the density of 7.84g/$cm^3$, the room temperature dielectric constant of 18400, the dielectric loss of 2.4%, the specific resistivity of $0.24{\times}10^{12}{\Omega}{\cdot}cm$. It also showed the bending strength of $120.7{\pm}11.26$ MPa and the fracture toughness of $0.87{\pm}0.002\;MPam^{1/2}$ which were comparable to commercial PZT. The microstructure sonsisted of grains of ∼4${\mu}m$. SEM and SIMS analysis showed that Ag grew as ∼1${\mu}m$ and excess MgO as ∼0.5${\mu}m$.

• Journal of Life Science
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• v.29 no.10
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• pp.1086-1095
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• 2019

This research was performed to develop a new material consisting of a mixture of Red Allium cepa (RA) Cucurbita moschata duch (CM), and Angelica gigas Nakai (AG). RA and CM have low storage stability because of their high moisture content. Therefore, their major components were extracted and used for the research after a content analysis. In order to overcome these limitations, the quercetin from RA, ${\beta}-carotene$ from CM, and decursin/decursinol angelate (D/DA) from AG were separately extracted, and the biochemical activity of each extract and mixture was compared. RA was bioconverted by the Bacillus subtillis KJ-3 (BS3) after ethanol extraction. After bioconversion, the quercetin content of RA was increased by 128.9%. ${\beta}-carotene$ was detected in the CM ethanol extract and its content was very low concentrations at 0.2 mg/g. The AG ethanol extract (1 mg) contained 0.4146 mg and 0.3659 mg of D/DA, respectively. The purity of the D/DA was found to be about 78%. The flavonoid and polyphenol content of each extract and their mixtures (mixture 1 (RA:CM:AG = 5:2:3), mixture 2 (RA:CM: AG = 3:5:2), and mixture 3 (RA:CM:AG = 3:2:5)) were measured. In addition, the cell survival rate, anti-inflammatory activity, and antioxidant ability were also evaluated. In all the results, the antioxidant activity of mixture 3 was most effective. Therefore, these findings provide basic data for future food development using a 3:2:5 mixture of RA, CM, and AG.

• Environmental Mutagens and Carcinogens
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• v.18 no.2
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• pp.104-108
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• 1998

In the present study, we have evaluated cytotoxic effects of Taraxaci Herba extract in human oral epitheloid carcinoma cells. An antitumor activity was measured by colorimetric assays using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and sulforhodamine protein B (SRB). The light microscopic study showed morphological changes, Ag-NOR (argyrophylic nucleolar organizer region) number and PAS positive reaction or the treated cells. These results obtained are as follows : MTT and SRB quantities were significantly decreased in cultured KB cells treated with 10$^{-2}$ /mg/ml and 10$^{-3}$ /mg/ml concentrations. The number of Ag-NORs were significantly decreased in cultured KB cells treated with 10$^{-2}$ /mg/ml and 10$^{-3}$ /mg/ml concentrations and the rate of Ag-NORs was shifted to left side (one Ag-Nounucleus was increased and five Ag-NORs/nucleus were decreased) by the high concentration. PAS reaction of cultured KB cells treated with 10$^{-2}$ /mg/ml and 10$^{-3}$ /mg/ml concentrations was negative. These results suggest that Taraxaci Herba retains a potential antitumor activity.

• Korean Journal of Materials Research
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• v.15 no.12
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• pp.791-795
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• 2005

In this study, aluminum borate whisker reinforced Mg-3Al-2Ag-1Zn matrix composites were fabricated by the squeeze infiltration technique. The purpose is to develop materials for elevated temperature applications. Microstructure observation revealed successful fabrication of the metal matrix composites, namely no cast defects such as porosity and matrix/reinforcement interface delamination etc. High temperature hardness and creep rupture properties were improved significantly with addition of Ag to the Al borate whisker reinforced Mg alloy composite. $Mg_3Ag$ phase formed during aging heat treatment could improve creep properties of the Mg matrix composites.

• Korean Journal of Materials Research
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• v.27 no.12
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• pp.695-698
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• 2017

ZnMgBeGaO/Ag/ZnMgBeGaO multilayer structures were sputter grown and characterized in detail. Results indicated that the electrical properties of the ZnMgBeGaO films were significantly improved by inserting an Ag layer with proper thickness (~ 10 nm). Structures with thicker Ag films showed much lower optical transmission, although the electrical conductivity was further improved. It was also observed that the electrical properties of the multilayer structure were sizably improved by annealing in vacuum (~35 % at $300^{\circ}C$). The optimum ZnMgBeGaO(20nm)/Ag(10nm)/ZnMgBeGaO(20nm) structure exhibited an electrical resistivity of ${\sim}2.6{\times}10^{-5}{\Omega}cm$ (after annealing), energy bandgap of ~3.75 eV, and optical transmittance of 65 % ~ 95 % over the visible wavelength range, representing a significant improvement in characteristics versus previously reported transparent conductive materials.