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Kim S.S.,Yeungnam University | Lee J.,Korean Intellectual Property Office
Carbohydrate Polymers | Year: 2014

Polyacrylonitrile (PAN)-chitosan double-face films and nanofibers were manufactured. PAN and a chitosan salt were dissolved in dimethyl sulfoxide, and then thin-layered on a glass plate or electro-spun followed by coagulation in sodium hydroxide solution. The morphology of the PAN-chitosan double-face films and nanofibers was analyzed by scanning electron microscopy. The thermal behavior and the glass transition temperature of PAN-chitosan blends were assessed by differential scanning calorimetry and dynamic mechanical analysis, respectively. The antibacterial efficacy was measured by a swatch test with bacterial suspensions. The PAN-chitosan nanofibers produced a 5-log reduction against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus. © 2013 Elsevier Ltd. All rights reserved. Source


Kim S.S.,Yeungnam University | Lee J.,Korean Intellectual Property Office
Industrial and Engineering Chemistry Research | Year: 2013

Antimicrobial polyacrylonitrile (PAN)/m-aramid hybrid film was prepared. PAN and m-aramid were dissolved in dimethyl sulfoxide, thin-layered on a glass plate, and then coagulated in distilled water. The morphology of the PAN/m-aramid hybrid film was analyzed by scanning electron microscopy. The molecular interaction between PAN and m-aramid was assessed by dynamic mechanical analysis. The antimicrobial efficacy was measured by a swatch test using bacterial suspensions. The PAN/m-aramid hybrid film produced a 7-log reduction against Escherichia coli and Staphylococcus aureus within 5-min contact time. © 2013 American Chemical Society. Source


Kim S.S.,Yeungnam University | Lee J.,Korean Intellectual Property Office
Industrial and Engineering Chemistry Research | Year: 2013

m-Aramid/chitosan hybrid films and nanosized webs were produced. The m-aramid and chitosan salt were dissolved in dimethyl sulfoxide followed by coagulation in a sodium hydroxide solution to produce the m-aramid/chitosan film. An electro-spinning process was used to prepare the nanosized web to increase the surface area of the m-aramid/chitosan hybrid composite for antimicrobial properties. The morphology of the m-aramid/chitosan hybrid composite was analyzed by scanning electron microscopy. The miscibility of the hybrid composite was determined by Fourier transform infrared spectroscopy and X-ray diffraction. The antimicrobial efficacy was measured by a swatch test with bacterial suspensions. The nanosized webs, which had enhanced surface area, produced a 7-log reduction against Escherichia coli and Staphylococcus aureus. © 2013 American Chemical Society. Source


Park Y.,Chonnam National University | Kang D.-H.,Korean Intellectual Property Office
Journal of Vibroengineering | Year: 2013

In this paper, we present a technique for fatigue reliability evaluation of a steel welding member. The probabilistic stress-life method is an important one for the fatigue reliability evaluation of a steel welding member. In this method, the stress range frequency distribution of the stress history of a steel welding member defined as a loading block is obtained from the stress frequency analysis and the parameters of the probability distribution for the stress range frequency distribution are used for numerical simulation. The probability of failure of the steel welding member under loading block is obtained from the Monte Carlo Simulation in conjunction with the Miner's Rule, the Modified Miner's Rule, and the Haibach's Rule for fatigue damage evaluation. Through this procedure, a fatigue reliability evaluation that can predict the number of loading block of failure and the residual fatigue life is possible. Source


Sul I.H.,Korean Intellectual Property Office | Youn J.R.,Seoul National University | Song Y.S.,Dankook University
Carbon | Year: 2011

A new protocol is proposed for quantitatively characterizing the dispersion state of carbon nanotubes (CNTs) embedded in a composite. Such characterization will allow CNT-filled composites to be designed and tailored in more systematic manner. CNTs/polymer composites with different dispersions and distribution states were prepared and their structure was examined. Quantitative image analysis was performed to obtain a "positional randomness index" that involves the contributions from the dispersion and distribution of nanoparticles. © 2010 Elsevier Ltd. All rights reserved. Source

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