• Macromolecular Research
• /
• v.17 no.6
• /
• pp.411-416
• /
• 2009

The color stabilization of antimicrobial blends was studied by using poly(hexamethylene guanidine) phosphate (PHMG) as a highly efficient biocidal and nontoxic agent. The Taguchi method was used to determine the optimum conditions for the blending of PHMG in polypropylene (PP) matrix. To improve the yellowing phenomena, two kinds of stabilizer were used together: tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)](IN1010) from phenol and tris(2,4-di-t-butylphenylphosphite) (IF168) from phosphorus. According to blend composition and mixing condition, six factors were chosen, with five levels being set for each factor. The orthogonal array was selected as the most suitable for fabricating the experimental design, L25, with 6 columns and 25 variations. The-smaller-the-better was used as an optimization criterion. The optimum conditions for these parameters were 10 phr for PHMG, 2 phr for IN1010, 1 phr for IF168, 10 min for mixing time, $210^{\circ}C$ for mixing temperature, and 30 rpm for rotation speed. Under these conditions, the yellowness index of the blend was 1.52. The processibility of the blends was investigated by Advanced Rheometric Expansion System (ARES). The blend with 0.5 w% PHMG content, diluted with PP, exhibited an antimicrobial characteristic in the shake flask method.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2002.11a
• /
• pp.67-76
• /
• 2002

Self-leveling material(SLM) is one of the floor finishing materials which make flat surface like as water level by itself in a short time. So it is possible to increase construction speed and enhance economical efficiency. In this study, author intended to develop SLM for the industrial warehouse and factory loading heavy weight machinery and vehicles. The demanded properties for this type of SLM are above 20mm of flow value and above 300kgf/cm2 of 28-days compressive strength. To possess demended strength and fluidity, SLM have to be composed of many types of binders and chemical additives. So it is difficult to decide suitable mixing proportion of composition materials. In this study, author investigated the weight percentage effect of main composition materials for high-strength self-leveling material, by experimental design such as tables of orthogonal arrays and simplex design, and by statistical analysis such as analysis of variance and analysis of response surface. Variables of experiments were ordinary portland cement(OPC), alumina cement(AC), anhydrous gypsum(AG), lime stone(LS) and sand, and properties of tests were fluidity of fresh state and strength of hardened state. Results of this study are showed that suitable mix proportions of binders for the high strength self-leveling materials are two groups. One is 78~85.5% OPC, 7.5~9.5% AC, 9~12.5% AG and the other is 72.5~78% OPC, 9~12.5% AC, 13~l5% AG.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.326-329
• /
• 2007

$CuInS_{2}$ thin films were synthesized by sulpurization of Cu/In Stacked elemental layer deposited onto glass Substrates by vacuum furnace annealing at temperature 200[$^{\circ}C$]. And structural and electrical properties were measured in order to certify optimum conditions for growth of the ternary compound semiconductor $CuInS_{2}$ thin films with non-stoichiometry composition. $CuInS_{2}$ thin film was well made at the heat treatment 200[$^{\circ}C$] of SLG/Cu/ln/S stacked elemental layer which was prepared by thermal evaporator, and chemical composition of the thin film was analyzed nearly as the proportion of 1 : 1 : 2. Physical properties of the thin film were investigated at various fabrication conditions substrate temperature, annealing and temperature, annealing time by XRD, FE-SEM and Hall measurement system. At the same time, carrier concentration, hall mobility and resistivity of the thin films was $9.10568{\times}10^{17}$ [$cm^{-3}$], 312.502 [$cm^{2}/V{\cdot}s$] and $2.36{\times}10^{-2}$ [${\Omega}{\cdot}cm$], respectively.

• Journal of the Korean Ceramic Society
• /
• v.43 no.1 s.284
• /
• pp.16-21
• /
• 2006

The preparation of $TiB_2$ by SHS in $B_2O_3-Mg-TiO_2$ system was investigated in this study. In the preparation of $TiB_2$, the effect on reactivity and reaction products of the initial pressure of inert gas in reactor, the content of Mg and $TiO_2$ in mixture was investigated. The minimum initial pressure of inert gas in reactor for SHS reaction in this system was 5atm, and as the pressure increased, the concentration of unreacted Mg decreased and combustion temperature increased. At the initial inert gas pressure in reactor of 50atm, the optimum composition for the preparation of pure $TiB_2$ was $B_2O_3+5Mg+TiO_2$. The $TiB_2$ synthesized in this condition had an irregular shape and the particle size of $1\~3{\mu}m$.

• Journal of the Korean Ceramic Society
• /
• v.16 no.2
• /
• pp.83-88
• /
• 1979

The Anorthite is useful compound for some ceramic industries but it is difficult to produce Anorthite because of its high melting point (1553$^{\circ}C$) and narrow firing range. On this study, glass frit was added to Anorthite batch composition to widen firing range and lower melting point. After mixing a glass frit $(Na_2O-CaO-6SiO_2)$ with Anorthite, it was melted and quenched. Ratio of Anorthite vs. glass frit was 9 : 1, 8.5 : 1.5, 8 : 2, 7.5 : 2.5, 7 : 3. In those batch composition added amount of $No_2O$ were between 1.3wt.% and 3.9wt.%. To find the thermal change of the quenched, D.T.A. was surveyed. The quenched were fired at various vitrification temperature and detected by X-Raydiffraction analysis. With addition of glass frit, firing range and vitrification temperature of Anorthite was 100~15$0^{\circ}C$ and 1050~115$0^{\circ}C$ respectively. Optimum amount of glass frit was 20wt.% for the upper mentioned.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.279-280
• /
• 2008

For the manufacture of the $CuGaS_2$, Cu, Ga and S were vapor-deposited in the named order. Among them, Cu and Ga were vapor-deposited by using the Evaporation method in consideration of their adhesive force to the substrate so that the composition of Cu and Ga might be 1 : 1, while the surface temperature having an effect on the quality of the thin film was changed from R.T.[$^{\circ}C$] to 150$[^{\circ}C]$ at intervals of 50$[^{\circ}C]$. As a result, at 400$[^{\circ}C]$ of the Annealing temperature, their chemical composition was measured in the proportion of 1 : 1 : 2. It could be known from this experimental result that it is the optimum condition to conduct Annealing on the $CuGaS_2$ thin film under a vacuum when the $CuGaS_2$ thin film as an optical absorption layer material for a solar cell is manufactured.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.11
• /
• pp.1638-1644
• /
• 2001

The objective of this research was to evaluate alternative treatments for the best extraction condition for collagen from chicken feet. Various properties such as chemical composition, amino acid, pH, swelling percentage, yield and pure collagen, collagen loss, color (Hunter L, a and b) and electrophoresis of collagen from chicken feet treated by 5% acids (acetic acid, citric acid. hydrochloric acid and lactic acid) and soaking times (12, 24, 36 and 48 h) were evaluated. The crude protein, fat, ash and moisture contents of chicken feet was 17.42, 12.04, 5.98 and 62.05%, respectively. Amino acid composition of collagen from chicken feet indicated that the protein of collagen was markedly hydrolized by the hydrochloric acid treatment. The result of electrophoresis also supported this phenomenon. Both the swelling percentage of lactic acid and citric acid treatments were significantly higher than that of acetic acid and HC1 treatment. The pH of the acid treatments ranged from 2.43-3.62. According to the result of yield, pure collagen and loss of collagen, the best condition of extracting collagen from chicken feet was soaked in 5% lactic acid for 36 h. However, a brighter yellow color of collagen from all treatments was observed with a longer soaking time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.11a
• /
• pp.258-259
• /
• 2005

[ $CuInSe_2$ ] thin films were fabricated at various fabrication conditions (substrate temperature, sputtering pressure, BC/RF power, vapor deposition, heat treatment). And structural and electrical properties were measured in order to certify optimum conditions for growth of the ternary compound semiconductor $CuInSe_2$ thin films with stoichiometric composition. $CuInSe_2$ thin film was well made at the heat treatment of 500[$^{\circ}C$] of SLG/Cu/In/Se stacked elemental layer which was prepared by sputter and thermal evaporator, and chemical composition of the thin film was analyzed nearly as the proportion of 1 : 1 : 2. At the same time, carrier concentration, hall mobility and resistivity of the thin films was $1.27\sim9.88\times10^{17}[cm^{-3}]$, $49.95\sim185[cm^2/V{\cdot}s]$ and $10^{-1}\sim10^{-2}[\Omega{\cdot}cm]$, respectively

• Elastomers and Composites
• /
• v.34 no.3
• /
• pp.253-261
• /
• 1999

The cure properties of rubber compounds containing different adhesive compositions were examined. As the amounts of tannin were increased in the adhesive composition, the scorch time was increased and cure rate was decreased due to the size and shape of tannin molecules. Also, the effect of adhesive composition on the adhesion between rubber and fiber was examined by TCAT(Tire Cord Adhesion Test), The reinforcing cords used in this study were mon ofilaments of nylon 610 and nylon 66. According to the results, the optimum adhesion strength between rubber and fiber could be obtained with adhesives whose molar ratios of formaldehyde/resorcinol were above 5/1 in the recipes. Although the level of dip pick-up(DPU) on the reinforcing cord affects the adhesion strength, the DPU of nylon 610 monofilament did not affect the adhesion strength because the level of DPU was constant regardless of the adhesive compositions. In this case, the adhesion strength with the adhesive composition could be explained with the behavior of tannin in the adhesive.

• The Korean Journal of Food And Nutrition
• /
• v.28 no.5
• /
• pp.766-773
• /
• 2015

This study analyzes the chemical composition of green tea, white tea, yellow tea, oolong tea and black tea with respect to extraction temperature and time. The optimum extraction conditions for these teas were determined by assessing the chemical composition of tea brewed at different temperature (50, 60, 70, $80^{\circ}C$) and extraction times (1, 3, 5, 10 minute). Catechins contents were the largest at 5 minutes and generally declined by 10 minutes. Green tea catechins contents were highest when brewed at $70^{\circ}C$ and besides other teas a change of the trend variation at 70 and $80^{\circ}C$. These temperatures did not extract theaflavins in green tea. Extract temperature and time did not significantly affect theaflavins content of white tea, yellow tea, and oolong tea. Black tea, however, was noticeably dependent on extract conditions, which were most effective at $70^{\circ}C$, brewed for 5 minutes. Caffeine content of green tea, yellow tea, and oolong tea was highest at 5 minutes, but temperature did not appear to affect the content. White tea and black tea caffeine content was highest when brewed at $70^{\circ}C$ for 5 minutes. Theobromine content of green tea, yellow tea, oolong tea, and black tea did not show major differences between the study times or temperature, though the content in white tea increased with higher temperatures when brewed for 5 minutes. The extraction of phenolic compounds increased until 5 minutes, and showed not further increase at 10 minutes. Antioxidant capacity of green tea, white tea, and yellow tea were maximized at $70^{\circ}C$ for 5 minutes or $80^{\circ}C$ for 3 minutes, while oolong and black tea were reached maximum antioxidants at $70^{\circ}C$ for 5 minutes. In general, to optimize the beneficial chemical content of brewed tea, a water temperature of $70^{\circ}C$ for 5 minutes is recommended.