• Macromolecular Research
• /
• v.16 no.2
• /
• pp.108-112
• /
• 2008

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of nonpolar polymeric materials is affected by the sample preparation as well as the matrix and cationizing agent. This study examined the influence of silver salt types on the MALDI analysis of polybutadiene (PB). Silver trifluoroacetate (AgTFA), silver benzoate (AgBz), silver nitrate ($AgNO_3$), and silver p-toluenesulfonate (AgTS) were used as the silver salts to compare the MALDI mass spectra of PB. The mixture solution of PB and 2,5-dihydroxybenzoic acid (DHB), as a matrix dissolved in THF, was spotted on the sample plate and dried. A droplet of the aqueous silver salt solution was placed onto the mixture. The mass spectrum with AgBz showed the clear $[M+Ag]^+$ ion distribution of PB while the mass spectrum with AgTFA did not show $[M+Ag]^+$ ions but only silver cluster ions. The mass spectra with $AgNO_3$ and AgTS did not show a clear $[M+Ag]^+$ ion distribution. The difference in the formation of $[M+Ag]^+$ ions of PB depending on the silver salts was attributed to the silver cation transfer reaction between the silver salt and the matrix (DHB). The mass spectrum showed a clear $[M+Ag]^+$ ion distribution of PB when the conjugate acid of the silver salt was less acidic than the matrix.

• Journal of Powder Materials
• /
• v.15 no.5
• /
• pp.386-392
• /
• 2008

Silver particles were synthesized from silver nitrate by homogeneous precipitation and chemical reduction methods involving the intermediate silver cyanate. The obtained silver particles were characterized by XRD, SEM, TEM, and BET. Urea which could prevent the agglomeration of the reduced silver particles was used as a homogeneous precipitator. The spherical silver particles with average particle diameter of 100 nm were obtained under the optimum reaction conditions. The optimum synthetic conditions were found as follows: reaction temperature $100^{\circ}C$, reaction time 60 min, concentration of silver nitrate $1{\times}10^{-2}$ mol, urea $5{\times}10^{-3}$ mol, and sodium citrate $8.5{\times}10^{-4}$ mol. The phase of obtained silver particles was crystalline state and the silver particles were relatively dense, which had the surface area of $0.7571\;m^{2}/g$.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.2
• /
• pp.505-509
• /
• 2013

A low temperature ($65^{\circ}C$) thermal deposition process was developed for depositing a silver coating on thermally sensitive polymeric substrates. This low temperature deposition was achieved by chemical reduction of a silver alkylcarbamate complex with latent reducing agent. The effects of acetol as a latent reducing agent for the silver 2-ethylhexylcarbamate (Ag-EHCB) complex and their blend solutions were investigated in terms of reducing mechanism, and the size and shape of silver nanoparticles (Ag-NPs) as a function of reduced temperature and time, and PVP stabilizer concentration were determined. Low temperature deposition was achieved by combining chemical reduction with thermal heating at $65^{\circ}C$. A range of polymer film, sheet and molding product was coated with silver at thicknesses of 100 nm. The effect of process parameters and heat treatment on the properties of silver coatings was investigated.

• Toxicological Research
• /
• v.30 no.3
• /
• pp.169-178
• /
• 2014

This review covers general information regarding the green synthesis of antibacterial silver nanoparticles. Owing to their antibacterial properties, silver nanoparticles are widely used in many areas, especially biomedical applications. In green synthesis practices, the chemical reducing agents are eliminated, and biological entities are utilized to convert silver ions to silver nanoparticles. Among the various biological entities, natural plant extracts have emerged as green reducing agents, providing eco-friendly routes for the preparation of silver nanomaterials. The most obvious merits of green synthesis are the increased biocompatibility of the resulting silver nanoparticles and the ease with which the reaction can be carried out. This review summarizes some of the plant extracts that are used to produce antibacterial silver nanoparticles. Additionally, background information regarding the green synthesis and antibacterial activity of silver nanoparticles is provided. Finally, the toxicological aspects of silver nanoparticles are briefly mentioned.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.145.2-145.2
• /
• 2003

We have developed a silver staining method using a dye as a silver sensitizer. Dye staining is performed in combination with silver nitrate staining. Dye-silver staining shortens the time of silver staining (~1 hr) and improves the sensitivity better than that of silver diamine stain (1-10 ng) or comparable to that of silver nitrate stain with glutaraldehyde as a silver sensitizer. In dye staining (silver sensitizing step), it has been proven that the sensitivity is at least 4 times comparing with that of CBBR stain and staining time is about 45 min. (omitted)

• Honam Mathematical Journal
• /
• v.43 no.4
• /
• pp.701-715
• /
• 2021

In this paper, we study almost complex Norden Silver manifolds and Kaehler-Norden Silver manifolds. We define adapted connections of first, second and third type to an almost complex Norden Silver manifold and establish the necessary and sufficient conditions for the integrability of almost complex Norden Silver structure. Moreover, we investigate that a complex Norden Silver map is a harmonic map between Kaehler-Norden Silver manifolds.

• Macromolecular Research
• /
• v.10 no.2
• /
• pp.80-84
• /
• 2002

Silver species other than the silver ion were formed by UV irradiation on polymer electrolyte membranes containing silver salts and their effect on complexation behavior between the silver and olefin was investigated through the separation performance of olefin/paraffin mixtures. The ideal propylene/propane separation factor reached 350 and the separation coefficient was ca.15 due to the high loading amount of silver ions into poly(2-ethyl-2-oxazoline) (POZ) without UV irradiation. On UV irradiation either in air or under nitrogen, the silver-POZ membranes became yellow-brown initially due to the formation of colloidal silver particles, and finally black and metal-like luster. Even when Ag$^{+}$ was converted, to some extent, to Ag$^{\circ}$ by UV irradiation in air at the early stage, the separation coefficient of olefin/paraffin mixtures was maintained. This suggests that silver species other than the silver ion is active for olefin carrier for facilitated transport. Meanwhile the steady decrease of the separation coefficient was observed in the silver/POZ membranes irradiated under $N_2$. It is suggested that the reduction of silver ions in POZ goes through a different photoreduction mechanism with UV irradiation depending on the environment.t.

• KSBB Journal
• /
• v.28 no.4
• /
• pp.249-253
• /
• 2013

In this study, we analyzed the attachment amount and the surface properties, such as shape and attachment aspect of silver nanoparticles on the surface of salt and sucrose. In addition, we investigated the antimicrobial activity of silver nanoparticles by measuring total colony counts and total coliforms in sewage according to the time and the amount of silver nanoparticles. As a result, it is found that silver nanoparticles are attached on the surface of salt and sucrose from the SEM images and there is no microorganisms on the surface of salt and sucrose. Silver nanoparticles on salt were rod shape but silver nanoparticles on sucrose were round shape. Also, the content of silver was 0.735 mg/g on salt and 0.885 mg/g on sucrose. In all experiments, total colony counts and total coliforms sharply declined initially, and it decreased gradually as change the time. When injection amount of nano silver sucrose and salt increased, the width of decline was greater. The amount of total colony counts and total coliforms of nano silver salt was much lower and the disinfection efficiency was higher comparing with nano silver sucrose. That means the case of nano silver salt is much better at the antimicrobial activity.

• Carbon letters
• /
• v.4 no.4
• /
• pp.168-174
• /
• 2003

Silver nitrate ($AgNO_3$) powder was mixed into a reformed pitch precursor. Then, the silver-containing pitch was melt spun to form round and "C" shape fibers. A wire mesh was inserted prior to the nozzle to improve the spinnability of the silvercontaining precursor pitch. Silver particles in the carbon fibers (CFs) were detected by XRD and TEM. These tests showed that silver particles were uniformly distributed and the total amount of silver remained constant during stabilization and carbonization. Next, the silver-containing CFs were activated by steam diluted in nitrogen gas. Silver particles accelerated the activation rate, but the specific surface areas of the silver-containing ACFs were similar to those of non-silver containing ACFs at the same burn-off levels. The specific surface area of the C-shaped activated carbon fibers was larger than that of the round activated carbon fibers. The likely reason is that the surface area of a C-shaped CF is about two times larger than that of a round CF when equivalent cross-sectional areas are compared. A small amount of silver particles in the periphery of the CFs was removed during the activation, but the remainder of silver was stayed within the ACFs.

• Archives of design research
• /
• v.15 no.2
• /
• pp.101-114
• /
• 2002

On the threshold of year 2000, the elderly account for more than 7% of the whole population in Korea, which means that the nation is greeting welcoming an aging society. Accordingly, it is expected that silver businesses and services targeted at the silver generation will prosper with "silver advertising design" becoming active. Under such circumstances, this study was aimed at reviewing the recent silver marketing advertisements in terms of their cultural and moral implications, and thereby, redefining and reestablishing the status of silver consumers to help them find their identity, aware of marketing activities and therewith, establish their "consumer sovereignty". This study consists in large of 5 chapters. The introduction parr describes background, purpose, method and scope of the study. The first chapter reviews the silver marketing theories. The second chapter classifies the silver marketing advertisement positioning of four style - upper classes style, effloresce progress style, self- sufficiency style, dependent style - and reviews the expression strategy of each positioning. The third chapter examines the domestic conditions of silver marketing advertisements for each positioning type classified. The fourth chapter designs the ′creative′of silver marketing advertisements and suggests the methods thereof. The analysis of ′creative′was tested in terms of graphic gestaltung, and how the sliver marketing advertisement positioning should be discerned depending on silver generation consumer′s characteristics was discussed. The fifth chapter puts forwards the suggestions for the ′creative′ strategies to enhance the effects of the silver marketing advertisements, based on the preceding discussions. In addition, the Perspective into the keyword of 21 st century or "silver design" is discussed, together with the limitations of this study. It is hoped that this stuffy will be conducive to our efforts to face the upcoming′age\ulcorner society′more effectively. To this end, this study discusses the "silver advertising design" in light of ′societal concepts′and ′customer-oriented value′, and thus, explores some creative presentation strategies whereby individual companies interests and social or public interests can be compromised through ′creative activities′ and ′equal-value consumerism′ for an ultimately effective management strategies for silver businesses and services.