간행물
한국응용과학기술학회지 KCI 등재 The Korean Society of Applied Science and Technology
- 발행기관 한국응용과학기술학회(구 한국유화학회)
- 자료유형 학술지
- 간기 격월간
- ISSN 1225-9098 (Print)2288-1069 (Online)
- 수록기간 1984 ~ 2024
- 주제분류 공학 > 화학공학 공학 분류의 다른 간행물
- 십진분류KDC 575DDC 665
권호리스트/논문검색
Vol.24 No.3 (2007년 9월) 13건
1.
2007.09
구독 인증기관 무료, 개인회원 유료
Based on the Benzoflex (Vesicol Chemical Co.) as PVC plasticizer substituents for Di-n-octyl phthalate (DOP), a series of new aromatic carboxylic acid ester compounds were designed as plasticizers, synthesized, and screened for the endocrine disrupting activity. 2-Hydroxybenzoic acid (1) and 2-methoxybenzoic acid (2) as the commercially available starting materials were reacted with diethylene glycol (3) in the presence of p-toluenesulfonic acid using Dean-Stark column to give diethylene glycol di-(2-hydroxy)benzoate (4, KH01) and diethylene glycol di-(2-methoxy)benzoate (5, KH02), respectively. And diethylene glycol di-(3-pyridinyl) ester (7, KH03) and dipropylene glycol di-(3-pyridinyl) ester (9, KH04) were obtained in high yields by treatment of nicotinoyl chloride (6) with diethylene glycol (3) and dipropylene glycol (8) in the presence of triethylamine as a base. To determine the estrogenic disrupting effect of new synthetic phthalate analogues, E-screen assay method was used. Of these compounds, 4 (KH01) was found to be compound without endocrine disrupting effect.
4,000원
2.
2007.09
구독 인증기관 무료, 개인회원 유료
In T-mixer crystallization, supersaturation is generated by mixing of another solvent or non-solvent in order to reduce the solubility of the compound. Also, T-mixer is a type of continuous crystallization. In order to induce micro-mixing, two solutions were mixed rapidly by T-mixer, which formed high supersaturation. As the results, mean size of HMX crystals decreased with increasing de-supersaturation rate (Rs). Eventually, HMX particles ranging from 0.5 to 5μm can be obtained by T-mixer crystallization. Mixing efficiency in T-mixer increased with increasing Rs values. In T-mixer crystallization without surfactants, homogeneous nucleation was formed when S and Rs was over 54 and 1.6×103/sec. In T-mixer crystallization with surfactants, homogeneous nucleation was formed when S and Rs was over 26 and 7.4/sec.
4,600원
3.
2007.09
구독 인증기관 무료, 개인회원 유료
This study is focused on the possibility of copper alloy metal fiber for an antimicrobial activity in the water soluble metal working fluids. Electrochemical potential of Cu/Zn ion is -268mV, and easily makes radicals with molecular oxygen. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper alloy metal fiber is detected in metal working fluid. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.
4,000원
4.
2007.09
구독 인증기관 무료, 개인회원 유료
Eu3+ doped YGdO3 phosphors particles which have fine size and narrow size distribution with non aggregated uniform morphology were prepared by solvent evaporation method for the improvement of emission efficiency. Several parameters have been investigated in this study such as the influences of composition ratio of host materials, calcination temperature, amount of activator, surfactant, pH and flux on the photoluminescence intensity, particle size and dispersion. Eu3+ doped YGdO3 phosphor presented a strong narrow band emission peak at 612nm. The maximum emission intensity ofYGdO3:Eu3+ occurred when Eu3+ concentration is 3wt% under vacuum ultra violet excitation. Prepared phosphors were found to have small round-shaped particles about 150nm in size. The addition of PVA as a surfactant inhibits the grain growth and the agglomeration of particles efficiently by reducing the oxygen bridge bonds. As the pH reduces, PL intensity increase due to reducing the formation of oxygen bridge bonds. The particles prepared from solvent evaporation method with 5wt% LiCl were found to have 120% PL intensity compare to particles prepared without LiCl flux.
4,000원
5.
2007.09
구독 인증기관 무료, 개인회원 유료
BaTiO3 powders were prepared by sol-gel method from different concentration of KOH aqueous solution and Ba/Ti molar ratio. Particle shape, size and crystal structure of prepared BaTiO3 powders were analyzed by SEM, XRD, and FT-IR. As the result of KOH concentration changing, spherical particles were obtained by condition more than 3 M and particle size decreased as concentration increasing. Different appearance showed between dried and sintered powders against changing of Ba/Ti molar ratio. In case of dried powders, the crystallinity decreased as molar ratio increasing. On the other hand, increased as molar ratio increasing in case of sintered powders.
4,000원
6.
2007.09
구독 인증기관 무료, 개인회원 유료
Three different weather-resistant coatings were fabricated with the various weight ratios of a mill-base silicone/acrylic resin to let-down silicone /acrylic resin at 2:8, 3:7, and 4:6 respectively. The prepared coatings were tested to investigate the effect of composition of weather-resistant coatings on the physical properties. The thermal stability, salt spray exposure, and weather-resistance were improved with the increased silicone content. It was concluded that the optimum retio of mill-base silicone/acrylic resin to let-down silicone/acrylic resin would be 2:8 and the coating with 30 wt% of silicone content would have high weather-resistance.
4,200원
7.
2007.09
구독 인증기관 무료, 개인회원 유료
Effect of dispersion methods for Vapor Grown Carbon Fibers (VGCF) in epoxy caused the change in mechanical properties of VGCF/epoxy nanocomposites, such as tensile modulus and tensile strength. The influence of VGCF types - atmospheric plasma treated (APT) VGCF and raw VGCF - and their contents was discussed in detail. Treating VGCF with atmospheric plasma enhanced the surface energy, therefore improved the bonding strength with epoxy matrix. Two different methods used to disperse VGCF were ultrasonic and mechanical homogenizer methods. When using dispersion solutions, the VGCF demonstrated good dispersion in ethanol in both homogenizer and ultrasonic method. The uniform dispersion of VGCF was investigated by scanning electron microscopy (SEM) which showed well-dispersion of VGCF in epoxy matrix. The tensile modulus of raw VGCF/epoxy nanocomposites obtained by ultrasonic method was higher than that of one obtained by homogenizer method. APT VGCF/epoxy nanocomposites showed higher tensile strength than that of raw VGCF/epoxy nanocomposites.
4,000원
8.
2007.09
구독 인증기관 무료, 개인회원 유료
Catalytic activity changes of perovskite catalysts were examined with their A-site substitution. For the preparation of catalysts, Mn was used for B-site component and La, Ce, Sr, Ba, Ca, Ag were used for A-site component of the perovskite catalysts(ABO3) The effect of calcination temperature on methane combustion and perovskite structure was also investigated. The surface area and adsorbed oxygen species were tested with BET apparatus and O2-TPD, respectively. Perovskite catalysts whose A-site was partially substituted needed higher calcination temperature than un-substituted one to form the perovskite structure. From O2-TPD experiment, it was found that methane combustion activity was directly related to the oxygen desorbing ability of the catalysts. The prepared catalyst(LM-7) was stable at 600℃ for 72 hours of reaction.
4,000원
9.
2007.09
구독 인증기관 무료, 개인회원 유료
As a part of enhancing the performance of wood-plastic composites (WPC), polypropylene (PP)/ nanoclay (NC)/ wood flour (WF) nanocomposites were prepared using melt blending and injection molding process to evaluate their thermal stability. Thermogravimetric analysis (TGA) was employed to investigate thermal degradation kinetics of the nanocomposites both dynamic and isothermal conditions. Dynamic scans of the TGA showed an increased thermal stability of the nanocomposites at moderate wood flour concentrations (up to 20 phr, percentage based on hundred percent resin) while it decreased with the addition of 30 phr wood flour. The activation energy (Ea) of thermal degradation of nanocomposites increased when nanoclay was added and the concentration of wood flour increased. Different equations were used to evaluate isothermal degradation kinetics using the rate of thermal degradation of the composites, expressed as weight loss (%) from their isothermal TGA curves. Degradation occurred at faster rate in the initial stages of about 60 min., and then proceeded in a gradual manner. However, nanocomposites with wood flour of 30 phr heated at 300℃ showed a drastic difference in their degradation behavior, and reached almost a complete decomposition after 40 min. of the isothermal heating. The degree of decomposition was greater at higher temperatures, and the residual weight of isothermal degradation of nanocomposites greatly varied from about 10 to 90%, depending on isothermal temperatures. The isothermal degradation of nanocomposites also increased their thermal stability with the addition of 1 phr nanoclay and of wood flour up to 20 phr. But, the degradation of PP100/NC1/MAPP3/WF30 nanocomposites with 30 phr wood flour occurs at a faster rate compared to those of the others, indicating a decrease in their thermal stability.
4,000원
10.
2007.09
구독 인증기관 무료, 개인회원 유료
Three phosphorus functional groups were introduced in one structural unit of polymer backbone to enhance the flame retardancy of PU coatings. In the first step, we synthesized tetramethylene bis(orthophosphate) (TBOP) that contained two phosphorus functional groups in one structural unit. In the next step, we synthesized modified polyesters (ATBTP-10C, -20C, -30C) that contained triphosphorus group using TBOP, 1,4-butanediol, trimethylolpropane, adipic acid, and another functional monomer, phenylphosphonic acid (PPA). The amount of PPA in ATBTPs was adjusted from 10 wt% to 30 wt%. The structure and characteristics of ATBTPs were examined using FT-IR, NMR, GPC, and TGA analysis. From the thermo-behavior test of diphosphorus modified polyester (ATBT) and ATBTPs, the afterglow of ATBT, ATBTP-10C, ATBTP-20C, and ATBTP-30C were 24.7, 27.1, 29.0, and 31.7%, respectively. It was found from this result that the afterglow increased with the amount of PPA component.
4,000원
11.
2007.09
구독 인증기관 무료, 개인회원 유료
This paper presents applicability of photocatalytic decomposition of methyl mercaptan using TiO2. A quartz reactor was used in order to elucidate reaction pathway in photocatalytic decomposition of methyl mercaptan. Experimental results showed that more than 99.9% of methyl mercaptan was decomposed within 30 minutes. It was found that the photocatalytic decomposition of methyl mercaptan followed pseudo first order and its reaction coefficient was 0.05min-1 During 30 minutes in the photocatalytic reaction, the concentration of methyl mercaptan, dimethyl disulfide, SO2, H2SO4, COS, H2S were determined. These results showed that 64% of methyl mercaptan were compensated for the increase in sulfur after 30 minutes through the mineralization. The proposed main photocatalytic decomposition pathway of methyl mercaptan was methyl mercaptan→dimethyl disulfide→SO2→H2SO4.
4,000원
12.
2007.09
구독 인증기관 무료, 개인회원 유료
From the experiment result on pharmacetical characteristics and analysis of Garlic extract, some conclusions were obtained as follows. From the results on extract experiment of Garlic, extraction ratio was about 6.0%, and after dried with dry oven from Garlic extract, it obtained about 50%-Garlic extract of solid state. From results on antimicrobial experiment of Garlic extract, number of staphylococcus and fungus in microbe decreased more and more according to time passage. This phenomenon showed that Garlic extract keeps antimicrobial effect. From results on antioxidation experiment of Garlic extract, DPPH scavenging activity of free radical showed that Garlic extract appears more remarkable reduction ability than reference samples. This phenomenon means that antioxidation of Garlic extract appears higher than Vitamin-C and BHA. From results on instrument analysis, inorganic components of K, Na, Ca, Si, Mg, Zn etcs from Garlic extract were detected with ICP/OES and the fatty and aromatic components of trimethyl sulfide, diallyl disulfide, diallyl trisulfide, 2-mercaptobenzothiazole etcs from Garlic extract were detected with GC/MS.
4,000원
13.
2007.09
구독 인증기관 무료, 개인회원 유료
Novolac is widely used as the primary solid component of most photoresists in semiconductor and microelectronic devices. In this study, novolac resins were prepared by condensation of 35% formaldehyde with phenolic compounds such as m-/p-cresol, 2,5-dimethylphenol and bisphenol A in the presence of oxalic acid as catalyst. The average molecular weight (Mw) of these novolac resins has been varied on the changing of mixing ratio of m-/p-cresol/2,5-dimethylphenol/bisphenol A or formaldehyde/phenolic compound. Also, thermal properties of novolac were observed by TGA.
4,000원
