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.18 No.3 (2001년 9월) 10건
1.
2001.09
구독 인증기관 무료, 개인회원 유료
While the equilibrium behaviour of surfactant solution is well studied, the understanding of the kinetics and pathways of structural transition under nonequilibrium conditions is only begining to develop. Attention has recently been directed mainly towards micellar kinectics, transitions between micellar and lamellar phases, vesicle fusion, and phases separation in microemulsions. This progress has profited greatly from developments that have taken place in various techniques and instruments.
4,000원
2.
2001.09
구독 인증기관 무료, 개인회원 유료
The spinel LiMn2O4 powders were synthesized at 480℃ for 12 h in air by a sol-gel method using manganese acetate and lithium hydroxide as starting material and the Fe3O4 powders were synthesized by the precipitation method using 0.2M-FeSO4·H2O and 0.5M-NaOH. The synthesized Fe3O4 powders were mixed at portion of 5, 10, 15 and 20 wt% about LiMn2O4 powders through ball-milling followed by drying at room temperature for 48 h in air. The mixed catalysts were reduced at 350℃ for 3 h by hydrogen and the decomposition rate of carbon dioxide was measured at 350℃ using the reduced catalysts. As the results of CO2 decomposition experiments, the decomposition rates of carbon dioxide were 85% in all catalysts but the initial decomposition rates of CO2 were slightly high in the case of the 5%-Fe3O4 added catalyst.
4,000원
3.
2001.09
구독 인증기관 무료, 개인회원 유료
The spinel Fe3O4 powders were synthesized using 0.2 M-FeSO4·7H2O and 0.5 M-NaOH by oxidation in air and the spinel LiMn2O4 powders were synthesized at 480 ℃ for 12 h in air by a sol-gel method using manganese acetate and lithium hydroxide as starting materials. The synthesized LiMn2O4 powders were mixed at portion of 5, 10, 15 and 20 wt% of Fe3O4 powders using a ball-mill. The mixed catalysts were dried at room temperature for 24 hrs. The mixed catalysts were reduced by hydrogen gas at 350 ℃ for 2 h. The carbon dioxide decomposition rates of the mixed catalysts were 90% in all the mixed catalysts but the decomposition rate of carbon dioxide was increased with adding LiMn2O4 powders to Fe3O4 powders.
4,000원
4.
2001.09
구독 인증기관 무료, 개인회원 유료
Antibiotics polymer prepared by chemical bonding and simple blending of antibacterial into polymers have attracted much interest because of their long-lasting and antibacterial activity. Antibiotics polymer can significantly reduce losses associated with dissolution, photolytic decomposition and volatillization. Further more, increased efficiency safety and selectivity are additional benefits which may be realized. In this study, Antibiotics polymer was synthesized by chemical reaction of polyacrylic acid with sulfamethazine by N,N'-dicyclohexylcarbodiimide(DCC) method. Antibacterial susceptibility was determined against Streptococcus pyrogenes[gram(+)] and Esherichia coli.[gram(-)] using a standardized disc test. As a result, the synthetic antibiotics polymer exhibited the broad susceptibilty against Streptococcus pyrogenes and Esherichia coli. Especially, the antibiotic effect of antibacterial polymer against Gram negative(Esherichia coli) was much stronger than that against Gram positive(Streptococcus pyrogenes).
4,000원
5.
2001.09
구독 인증기관 무료, 개인회원 유료
By fabricating the organic light-emitting devices (OLEDs) based on phosphorescent material, the internal quantum efficiency can reach 100%, compared to 25% in the case of the fluorescent material. Thus, the phosphorescent OLEDs have recently been extensively studied and showed higher internal quantum efficiencies then the conventional OLEDs. In this study, we investigated the characteristics of the phosphorescent OLEDs, with the green emitting phosphor, Ir(ppy)3, (tris(2-phenylpyridine)iridium). The devices with a structure of ITO/TPD/Ir(ppy)3 doped in the host material /BCP/Alq3/Li:Al/Al were fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of Ir(ppy)3, we fabricated several devices and investigated the device characteristics. OLEDs doped into BCP by 10% showed the best characteristics. For 10% doped OLEDs, the maximum luminance of was over 10000 cd/m2, and the maximum power efficiency was 7.14 lm/W.
4,000원
6.
2001.09
구독 인증기관 무료, 개인회원 유료
Organic semiconductors based on vacuum-deposited films of fused-ring polycyclic aromatic hydrocarbon have great potential to be utilized as an active layer for electronic and optoelectronic devices. In this study, pentacene thin films and electrode materials were deposited by Organic Molecular Beam Deposition (OMBD) and vacuum evaporation respectively. For the gate dielectric layer, photoacryl (OPTMER PC403 from JSR Co.) was spin-coated and cured at 220℃. Electrical characteristics of the device were investigated, where the channel length and width was 50 μm and 5 mm. It was found that field effect mobility was 0.039 cm2V-1s-1, threshold voltage was -8 V, and on/off current ratio was 106. Further details will be discussed.
4,000원
7.
2001.09
구독 인증기관 무료, 개인회원 유료
Conjugate trienoic acids (CTA) occurred in triacylglycerols (TGs) of the seed oils of Trichosanthes kirilowii, Momordica charantia and Aleurites fordii, and they were easily converted to their methyl esters in a mixture of sodium methoxide-methanol without any structural destruction. The main fatty acids in triacylglycerol (TG) fraction of the seed oils of Trichosanthes kirilowii are C18:2Ω6 (32.2 mol %), C18:3 9c.11t,13c (38.0 mol %) and C18:1Ω9 (11.8 mol %), followed with C16:0 (4.8 mol %) and C18:0 (3.1 mol %). The TG fraction was resolved into 20 TG molecular species according to the partition number (PN) by reversed-phase (RP)-HPLC. The main TG species were DTc2, MDTc and D2Tc, of which amounts reached 63 mol % of total TG molecular species. The TG sample was fractionated into 11 fractions according to the number of double bond in the molecule by Ag+-HPLC and the species of DTc2, MDTc and D2Tc were also eluted as main components. The TG species containing CTA showed unusual behaviours in the order of elution by HPLC ; first, TG moleular species of DTc2 (D; dienoic acid, Tc; punicic acid, Tci; α-eleostearic acid, M ; monoenoic acid, St; stearic acid) was eluted earlier than Mtc2, although they have the same PN number of 40, and, secondly, the species of DTci2 with eight double bonds was eluted earlier than that of D2Tci with seven double bonds. Intact TG of the seed oils of Momordica charantia contained mainly fatty acids such as C18:3Ω9c,11t,13t (57.7 mol %), C18:1Ω9 (17.4 mol %), C18:0 (12.3 mol %) and C18:2Ω6 (10.6 mol %), and was classified into 13 fractions by RP-HPLC. The main TG species were as follows ; MTci2 [(C18:1Ω9)(C18:3 9c,11t,13t)2, 39.1 mol %] and StTci2 [(C18:0)(C18:3 9c,11t,13t)2, 33.9 mol %] comprising about 73 mol % of total TG species, accompanied by DTci2 [(C18:2Ω6)(C18:3 9c,11t,13t)2, 7.3 mol %], D2Tci [ (C18:2Ω6)2(C18:3 9c,11t,13t), 3.6 mol %] and MDTci [(C18:1Ω9)(C18:2Ω6)(C18:3 9c,11t,13t), 3.5 mol %]. Simple TG species of Tci3 [(C18:3 9c,11t,13t)3] was present in a small amount of 1.4 mol %, but other simple TG species were not detected. The TG was also resolved into 11 fractions according to the number of double bond by Ag+-HPLC, and the species were mainly occupied by MTci2 [(C18:1Ω9)(C18:3 9c,11t,13t)2, 39.4 mol %] and StT-ci2 [(C18:0)(C18:3 9c,11t,13t)2, 35.4 mol %] DTci2 species with eight double bonds was also developed faster than D2Tci one with seven double bonds as indicated in the analysis of TG of the seed oils of T. kirilowii, and MTci2 species with cis, trans, trans-configurated double bond was eluted earlier than MTc2 species with cis, trans, cis-configurated double bond. The main components of fatty acid in total TG fraction isolated from the seed oils of of Aleurites fordii were in the following order ; C18:3 9c,11t,13t (81.2 mol %)〉 C18:2Ω6 (8.5 mol %)〉 C18:1Ω9 (5.4 mol %). With resolution of the TG by RP-HPLC, eight fractions such as Tci3, Dtci2, D2Tci, MTci2, PTci2 (P; palmi..
5,100원
8.
2001.09
구독 인증기관 무료, 개인회원 유료
CTA ester bonds in TG molecules were not attacked by pancreatic lipase and lipases produced by microbes such as Candida cylindracea, Chromobacterium viscosum, Geotricum candidium, Pseudomonas fluorescens, Rhizophus delemar, R. arrhizus and Mucor miehei. An aliquot of total TG of all the seed oils and each TG fraction of the oils collected from HPLC runs were deuterated prior to partial hydrolysis with Grignard reagent, because CTA molecule was destroyed with treatment of Grignard reagent. Deuterated TG (dTG) was hydrolyzed partially to a mixture of deuterated diacylglycerols (dDG), which were subsequently reacted with (S)-(+)-1-(1-naphthyl)ethyl isocyanate to derivatize into dDG-NEUs. Purified dDG-NEUs were resolved into 1, 3-, 1, 2- and 2, 3-dDG-NEU on silica columns in tandem of HPLC using a solvent of 0.4% propan-1-o1 (containing 2% water)-hexane. An aliquot of each dDG-NEU fraction was hydrolyzed and (fatty acid-PFB ester). These derivatives showed a diagnostic carboxylate ion, (M-1)-, as parent peak and a minor peak at m/z 196 (PFB-CH3)- on NICI mass spectra. In the mass spectra of the fatty acid-PFB esters of dTGs derived from the seed oils of T. kilirowii and M. charantia, peaks at m/z 285, 287, 289 and 317 were observed, which corresponded to (M-1)- of deuterized oleic acid (d2-C18:0), linoleic acid (d4-C18:0), punicic acid (d6-C18:0) and eicosamonoenoic acid (d2-C20:0), respectively. Fatty acid compositions of deuterized total TG of each oil measured by relative intensities of (M-1)- ion peaks were similar with those of intact TG of the oils by GLC. The composition of fatty acid-PFB esters of total dTG derived from the seed oils of T. kilirowii are as follows; C16:0, 4.6 mole % (4.8 mole %, intact TG by GLC), C18:0, 3.0 mole % (3.1 mole %), d2C18:0, 11.9 mole % (12.5 mole %, sum of C18:1Ω9 and C18:1Ω7), d4-C18:0, 39.3 mole % (38.9 mole %, sum of C18:2Ω6 and its isomer), d6-C18:0, 41.1 mole % (40.5 mole %, sum of C18:3 9c,11t,13c, C18:3 9c,11t,13r and C18:3 9t,11t,13c), d2-C20:0, 0.1 mole % (0.2 mole % of C20:1Ω9). In total dTG derived from the seed oils of M. charantia, the fatty acid components are C16:0, 1.5 mole % (1.8 mole %, intact TG by GLC), C18:0, 12.0 mole % (12.3 mole %), d2-C18:0, 16.9 mole % (17.4 mole %, sum of C18:1Ω9), d4-C18:0, 11.0 mole % (10.6 mole %, sum of C18:2Ω6), d6-C18:0, 58.6 mole % (57.5 mole %, sum of C18:3 9c,11t,13t and C18:3 9c,11t,13c). In the case of Aleurites fordii, C16:0; 2.2 mole % (2.4 mole %, intact TG by GLC), C18:0; 1.7 mole % (1.7 mole %), d2-C18:0; 5.5 mole % (5.4 mole %, sum of C18:1Ω9), d4-C18:0 ; 8.3 mole % (8.5 mole %, sum of C18:2Ω6), d6-C18:0; 82.0 mole % (81.2 mole %, sum of C18:3 9c,11t,13t and C18:3 9c,11t,13c). In the stereospecific analysis of fatty acid distribution in the TG species of the seed oils of T. kilirowii, C18:3 9c,11t,13r and C18:2Ω6 were mainly located at sn-2 and sn-3 position, while saturated acids were usually present at sn-1 position. And the major molecular species of (C18:2Ω6)(C18:3 9c,11t,13c)2 and (C18:1Ω9)(C18:2Ω6)(C18:3 9c,11t,13c) were predominantly composed of the stereoisomer of sn-1-C18:2Ω6, <..
5,400원
9.
2001.09
구독 인증기관 무료, 개인회원 유료
The transparent organic-inorganic hybrid films were prepared by the Sol-Gel process. PVP(polyvinylpyrrolidone) was used in organic component and TEOS(tetraethoxysilane) was used in inorganic component. HCI, CH3COOH, and NH4OH were used as the Sol-Gel catalyst. The characteristics according to not only the variation of organic and inorganic contents but also the variation of catalyst species and contents were investigated. On the whole, the compatibility was remained between organic and inorganic components, and also as the TEOS contents were increased, mostly the transparency and the mechanical, thermal properties were improved. In addition, as content of catalysts was increased, the films showed characteristics that were closer to PVP than silica. Although the transparency of films was preserved in HCI and CH3COOH, only the film containing more than 40wt% TEOS in NH4OH showed different phenomena.
4,000원
10.
2001.09
구독 인증기관 무료, 개인회원 유료
Aqueous urethane dispersion resin begins to assume commercial importance due to increasing environmental awareness of VOC in coating industry. Moreover there have been strong industrial needs for the development of reactive-type polyurethane flame retardant coatings. In this study, chlorinated polyester polyols were synthesized by two step polycondensation reaction using mono chloroacetic acid, adipic acid, trimethylol propane, and 1,4-butanediol. In the next step polyurethane dispersion was prepared using these chlorinated polyester polyols and isophorone diisocyanate with dimethylol propionic acid(DMPA) and trimethylamine. The structure of chlorinated polyol was characterized by GPC, FT-IR and NMR. Particle size and its distribution were examined in terms of various dispersion parameters including molecular weight and composition of polyol, amount of DMPA, and NCO/OH ratio, etc. The effect of chlorinated polyols on flammability was also evaluated.
4,000원
