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.22 No.2 (2005년 6월) 13건
1.
2005.06
구독 인증기관 무료, 개인회원 유료
Carbon composites were prepared with pitch-based round, C, hollow-type carbon fibers and pitch matrix. The thermal conductivities parallel and perpendicular to the fiber axis were measured by steady-state method. It was found that the thermal conductivities depended on the cross-sectional forms of the reinforcing fibers as well as the reinforcing orientation and carbon fiber precusors. Especially, mesophase pitch-based hollow carbon fiber-carbon composites had the most excellent thermal anisotropy, which was above 100.
4,000원
2.
2005.06
구독 인증기관 무료, 개인회원 유료
Core-shell polymers of methyl methacrylate-styrene system were prepared by sequential emulsion polymerization in the presence of sodium dodecyl benzene sulfonate(SDBS) as an emulsifier using ammonium persulfate(APS) in an initiator and the characteristics of these core-shell polymers were evaluated. Core-shell composite latex has the both properties of core and shell components in a particle, whereas polymer blends or copolymers show a combined physical properties of two homopolymers. This unique behavior of core-shell composite latex can be used in various industrial fields. However, in preparation of core-shell composite latex, several unexpected matters are observed, for examples, particle coagulation, low degree of polymerization, and formation of new particles during shell polymerization. To solve this matters, we study the effects of surfactant concentrations, initiator concentrations, and reaction temperature on the core-shell structure of PMMA-PSt and PSt-PMMA. Particle size and particles distribution were measured by using particle size analyzer, and the morphology of the core-shell composite latex was observed by using transmission electron microscope. Glass temperature was also measured by using differential scanning calorimeter. To identify the core-shell structure, pH of the composite latex solutions was measured.
4,000원
3.
2005.06
구독 인증기관 무료, 개인회원 유료
Bio-diesel as fatty acid methyl ester was derived from such oils as soybean, peanut and canola oil by lipase catalyzed continuous trans-esterification. So the activation of lipase(Novozym - 435) was kept to be up to 4:1, the limiting molar ratio of methanol to oil under one-step addition of methanol due to the miscibility of oil and methanol through the static mixer for 4hrs and the elimination of glycerol on the surface of lipase by 7wt% silica gel. Therefore the overall yield of fatty acid methyl ester from soybean oil appeared to be 98% at 50·C of reaction temperature under two-steps addition of methanol with 2×2:1 of methanol to oil molar ratio at an interval of 5.5hrs, 7wt% of lipase, 24 number of mixer elements, 0.2ml/min of flow rate and 7wt% of silica gel.
4,000원
4.
2005.06
구독 인증기관 무료, 개인회원 유료
Room temperature cure type of acryl-urethane coatings with high solid content were prepared in this study. Acrylic resins with 80% solid content were cured with hexamethylene diisocyanate (Desmodure N-3600). The cure time of prepared coatings BEHCC-84 (BEHC-84 : Tg=0℃) and BEHCC-87 (BEHC-87 : Tg=30℃), measured by rigid-body pendulum method, was recorded 8.3 hours and 3.8 hours, respectively. Dynamic viscoelastic experiment also revealed the glass transition temperature of BEHCC-84 and BEHCC-87 to be Tg=40.3℃ and Tg=43.3℃, respectively. It was found that the adhesion and flexural properties among various propeties of coatings were enhanced by the incorporation of caprolactone acrylate monomer into the acrylic resins.
4,000원
5.
2005.06
구독 인증기관 무료, 개인회원 유료
Reaction intermediates PCP/BZA (PBI) and tetramethylene bis(orthophosphate)(TBOP) were synthesized from polycaprolactone (PCP) and benzoic acid (BZA) and from pyrophosphoric acid and 1,4-butanediol, respectively. Benzoic acid modified polyesters containing phosphorus (APTB-S, -10, -15) were synthesized by polycondensation of the prepared PBI (containing 5, 10, 15wt% of benzoic acid), TBOP, adipic acid, and 1,4-butanediol. Network structured PU flame-retardant coatings (APHD) were prepared by curing the synthesized benzoic acid modified polyesters containing phosphorus (APT B - 5 , -10, -15) with hexamethylene diisocyanate (HDI)-timer. From the TGA analysis of APTBs, it was found that the afterglow decreased with the amount of BZA content at the high temperatures. With the introduction of BZA, the film viscosity and film hardness of APHD decreased. With the introduction of caprolactone group, the flexibility, impact resistance, accelerated weathering resistance of APTBs increased. Flame retardancy of the coatings was tested. In a vertical burning method, APHD shows 210~313 seconds, which indicates that the coatings are good flame-retardant coatings. Moreover, the amount of afterglow and flame retardancy of the coatings are decreased with increasing BZA content.
4,500원
6.
2005.06
구독 인증기관 무료, 개인회원 유료
This paper presents applicability of Fenton oxidation to perchloroethylene(PCE) contaminated soil. The initial concentration of PCE was 187mg/kg and Fenton oxidation conditions were 1.0M H2O2 and 0.5M Fe2+. More than 97% of PCE decomposition and 98% of dechlorination were obtained within 5 hrs. It was found that the decomposition of PCE by Fenton oxidation was followed pseudo first order and its reaction coefficient was 0.78 hr-1. GC-MS and GC-ECD analysis of reaction intermediates confirmed only the presence of trichloroacetic acid(i.e., 1.0% of initial PCE concentration). Under Fenton oxidation conditions, it was proposed that PCE was decomposed not simultaneously but one by one.
4,000원
7.
2005.06
구독 인증기관 무료, 개인회원 유료
The natural graphite particles A and heat-treated graphite particles B at 1800 ℃ after pitch-coating were used as the anode base materials for lithium ion secondary battery. In order to improve the performance of anode materials, the base anode materials were treated with various acids. With the acid treatments of 62% HNO3 and 95% H2SO4 aqueous solution, the specific surface area and electrical conductivity of base anode materials were increased, and the initial charge-discharge capacity and cycle performance were improved due to the elimination of structural defects.
4,000원
8.
2005.06
구독 인증기관 무료, 개인회원 유료
Many researchers have been focused on polymer electrolyte membrane (PEM) to improve performance of a fuel cell. Sulfonpolyimide with hydrocarbon was synthesized from ODA (4,4-diaminodiphenyl ether), ODADS (4,4-diaminodiphenyl ether-2,2-disulfonic acid), NTDA (1,4,5,8-naphthalenetetracarboxylicdianhydride) and CSA (chlorosulfonic acid). In order to estimate the feasibility as a fuel cell, the performance of sulfonpolyimide was analyzed through a swelling degree, IEC (ion exchange capacity), ion conductivity and TEM (transmission electron microscope). As the results of this performance test, swelling degree, IEC and ion conductivity were 37%, 0.06 meq/g and 0.08 S/cm respectively, when the CSA concentration was 0.4 M. It was thought that sulfonpolyimide could be used as a fuel cell through improvement of electrolyte membrane.
4,000원
9.
2005.06
구독 인증기관 무료, 개인회원 유료
The extraction yield of Corni fructus was about 47.5% by extract apparatus. This study was done to investigate the antidiabetic and antioxidative effects of Corni fructus in Streptozotocin (STZ)-induced diabetic rats. The contents of serum glucose, total cholesterol and hepatic lipid peroxide, glutathione were significantly decreaed (p<0.05) in Corni fructus treated group compared to the those of STZ-control group, also content of triglyceride (TG), atherogenic index (AI) and activity of catalase were decreased, but not statistically significant. High density lipoprotein (HDL)-cholesterol and HDL-cholesterol/total cholesterol ratio (HTR) were increased in Corni fructus treated group compared to the those of STZ-control group. The activities of glutathione-S-transferase (GST) and superoxide dismutase (SOD) were significantly decreaed (p<0.05) in Corni fructus treated group compared to the those of STZ-control group. The content of hepatic glycogen and activities of glucose-phosphate dehydrogenase (G-6 PDH), glucokin-ase were significantly increased, but activity of glucose-Grphosphatase (G-6 Pase)was decreased in Corni fructus treated group compared to the those of STZ-control group. Therefore, these results indicated that ethanol extract of Corni fructus would have antidiabetic and antioxidative effects in STZ-induced diabetic rats.
4,200원
10.
2005.06
구독 인증기관 무료, 개인회원 유료
Aluminum tri-butoxide was mixed with the water/ethanol solution and then chloroplatinic acid was added to the solution. The solution was dried at 100℃ for 15hrs to remove the solvent and water then it was calcined at 500℃. The catalyst was activated with a gas mixture. During the activation, the temperature was increased from 150℃ to 500℃. The necessary amount of urea was dissolved in 50mL water and injected. Aqueous urea solution was then mixed with the feed gas stream. At low temperatures, nitrogen containing compounds of urea decomposition are used as reductants in the reducton of NOX. However at high temperatures the nitrogen containing compounds are oxidized to NO and NO2 by oxygen instead of being used in the reduction. The activity of the catalyst was dependent on urea concentration in the feed stream when there was not adequate water vapor in the feed. The maximum conversion was shifted from 250℃ to 150℃ when water concentration was increased from 2 to 17%. It seems that the maximum temperature shifts to lower temperatures because the hydrolysis rate of HNCO increases with water, resulting in higher amounts of NH3.
4,000원
11.
2005.06
구독 인증기관 무료, 개인회원 유료
The spherical particles of CeO2/SiO2 composite powder with narrow-size distribution and pure phase particles were synthesized by ultrasonic spray pyrolysis method from aqueous cerium sulfate solution. The resulting composite powder was characterized by X-ray diffraction, scanning electron microscopy, transmittance electron microscopy, in-vitro sun protect factor, and BET surface area analysis. The concentration of cerium sulfate was tested to vary the particle size from 3.40×10-3 to 1.02×10-2mol/cm3 to study concentration effect of starting material. The average particle size from the 3.40×10-3mol/cm3 concentration was found to be slightly smaller than that from the 1.02×10-2mol/cm3 concentration, because of the relation between the droplet size and the concentration of the starting material solution
4,000원
12.
2005.06
구독 인증기관 무료, 개인회원 유료
The propagation of light radiation within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is important. To obtain the results of scattering coefficients(μs) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of (I /Io)wavelength vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements.
4,000원
13.
2005.06
구독 인증기관 무료, 개인회원 유료
Removable protective adhesives for automobiles were synthesized by an emulsion polymerization of monomers such as n-butyl acrylate (BA), n-butyl methacrylate (BMA), acrylonitrile (AN), acrylic acid (AA) and 2-hydroxyethyl methacrylate (2-HEMA), in which AA and 2-HEMA were functional monomers. Potassium persulfate (KPS) was used as an initiator and sodium lauryl sulfate (SLS) was used as an emulsifier, and polyvinyl alcohol (PVA) was used as a stabilizer. Emulsion polymerization was carried out in a semi-batch type reactor. Tensile strength, extension, peel strength, viscosity and solid content of the synthesized adhesives were tested. The optimum physical properties of the removable protective adhesives for automobiles were obtained with the composition of 0.43 mole BA, 0.57 mole AN, 0.21 mole BMA, 0.03 mole AA, and 0.03 mole 2-HEMA.
4,000원
