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        검색결과 4,563

        2961.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This studies were performed to develop a Korean traditional folk liquor namely Gangha-ju has been prepared at Bosung district in Korea, and manufacturing conditions and anti-oxidation activity and anti-microbial activity of Gangha-ju were investigated. Ethyl-alcohol 20% and 30% Gangha-ju were brewed with glutinous rice wine, distilled liquor and 6 herbs of ginger, cinnamon, etc. Chemical and physical properties of 30% Gangha-ju were acidity 0.22, pH 4.31, amino acidity 3.26, transmittance 59 and conductivity 911 μs/m, and 20% Gangha-ju were 0.43, 4.20, 6.26, 62 and 924 μs/m. Volatile flavor compounds of ethyl alcohol, acetic acid, butanol, n-amyl alcohol, iso-pentyl alcohol, ethyl acetate, butyl acetate, acetaldehyde and furfural were detected, and main aroma compounds of Gangha-ju were isopentyl alcohol and ethyl acetate. Anti-oxidation activity by DPPH method was evaluated 31.32%, and nitrite scavenging effect was 31.79%. Anti-microbial activity against several microorganisms was pronounced strong activity over a wide range of test organisms, and Leuconostoc mesenteroids and Salmonella Ttyphimurium, Staphylococcus epidermidis were found to be more sensitive to Gangha-ju than Escherichia coli and Aspergillus flavus.
        4,300원
        2962.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, imbedded copper matrix powders have been successfully prepared from the () composite salt solution. The composite powders were formed by drying the solution at 200~40 in the hydrogen atmosphere. Photocatalytic characteristics was evaluated by detecting TOC (total organic carbon) amount with TOC analyzer (model 5000A Shimadzu Co). Phase analysis of composite powders was carried out by XRD, DSC and powder size was measured with TEM. The mean particle size of composite powders was about 100 nm and a few zinc and copper oxide phases was included. The reduction ratio of TOC amount was 60% by the composite powders under the UV irradiation for 8 hours
        4,000원
        2963.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        nanopowder was synthesized by chemical vapor condensation (CVC) process and its photocatalytic property depending on microstructure was considered in terns of decomposition rate of organic compound. In order to control microstructure of nanopowder such as particle size and degree of agglomeration, precursor flow rate representing number concentration was changed as a process variable. In TEM observation, spherical nanoparticles with average size of 20 nm showed gradual increases in particle size and degree of agglomeration with increase of precursor flow rate. Also decomposition rate of organic compound increased with decreasing precursor flow rate. Thus, it was concluded that photocatalytic property was enhanced by targe surface area of disperse nanoparticles synthesized at lower precursor flow rate condition in CVC process
        4,000원
        2964.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        WC and dense WC-10 vol%Co materials with grain size of~1 were synthesized by high-frequency induction heated combustion synthesis (HFIHCS) method in one step from elemental powders of W, C and Co within several minutes. Simultaneous combustion synthesis and densification were accomplished under the combined effects of an induced current and mechanical pressure. In the absence of cobalt additive, WC can be formed, but its relative density was low (about 73%) under simultaneous application of a 60 MPa pressure and the induced current. However, in the presence of 10 vol.%Co, the relative density increased to 99% under the same experimental condition. The percentages of the total shrinkage occurring before and during the synthesis reaction of WC-10 vol.%Co were 5% and 51%, respectively. The fracture toughness and hardness values of WC-10 vol.%Co were 10 MPa . m and 1840 kg/, respectively.
        4,000원
        2965.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Aluminum-based composites were fabricated by a powder-in sheath rolling method. A stainless steel tube with outer diameter of 12 mm and wall thickness of 1 mm was used as a sheath. A mixture of aluminum powder and particles of which volume content was varied from 5 to 20%, was filled in the tube by tap filling and then rolled by 75% reduction in thickness at ambient temperature. The rolled specimen was then sintered at 56 for 0.5 h. The mixture of Al powders and particles was successfully consolidated by the sheath rolling. The composite fabricated by the sheath rolling showed a recrystallized structure, while unreinforced Al powder compact fabricated by the same procedure showed a deformed structure. The unreinforced Al powder compact was characterized by a deformation (rolling) texture of which main component is {112}<111>, while the composite showed a mixed texture oi deformation and recrystallization. The sintering resulted in recrystallization in Al powder compact and grain growth in the composite.
        4,000원
        2966.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The powder-in sheath rolling was applied to the fabrication of composite. A stainless steel tube with outer diameter of 12 mm and wall thickness of 1 mm was used as a sheath. Mixture of aluminum powder and particles of which volume content was varied from 5 to 20 vol.% was filled in the tube by tap filling and then rolled to 75% reduction at ambient temperature. The re]]ed specimen was sintered at 56 for 0.5 hr. The composite fabricated by the sheath rolling and subsequent sintering showed the relative density higher than 0.96. The tensile strength of the composite increased with the volume content of particles, and it reached a maximum of 90 MPa which is 1.5 times higher than unreinforced material. The elongation decreased with the volume content of particles. It is concluded that the powder-in sheath rolling is an effective method for fabrication of composite.
        4,000원
        2967.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanocrystalline materials of Ni and Ni-Cu alloy have been synthesized by the pulsed wire evaporation (PWE) method and these abnormal magnetic properties in the magnetic ordered state have been characterized using both VSM and SQUID in the range of high and low magnetic fields. Ni and Ni-Cu particles with an average size of 20 to 80 nm were found to influence magnetic hysterisis behavior and the results of powder neutron diffraction patterns and saturation magnetization curves are shown to indicate the absence of the NiO phase. The shifted hysterisis loop and irreversibility of the magnetization curve in the high field region were observed in the magnetic-ordered state of both Ni and Ni-Cu. The virgin magnetization curve for Ni slightly spillover on the limited hysterisis loop (20kOe). This irreversibility in the high field of 50 kOe can be explained by non-col-linear behavior and the existence of the metastable states of the magnetization at the surface layer (or core) of the particle in the applied magnetic field. Immiscible alloy of Cu-Ni was also found to show irreversibility having two different magnetic phases.
        4,000원
        2972.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is an investigation of comparative and contrasting characteristics of service in manufacturing sector - especially quality aspects. A review of both service and manufacturing industries'' systems literature revealed conflicting views on definin
        4,000원
        2973.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An intermediate, tetramethylene bis (orthophosphate), was prepared by the esterification of pyrophosphoric acid and l,4-butanediol. Then pyrophosphoric-containing modified polyesters (ATTBs) were synthesized by polycondensation of tetramethylene bis(orthophosphate), trimethylolpropane, adipic acid, and l,4-butanediol. The content of l,4-butanediol was varied from 10 to 20wt% for the reaction. The increase of the amount of l,4-butanediol in the synthesis of ATTBs resulted in increase in average molecular weight and decrease in kinematic viscosity owing to the excellent flowability and reactivity of l,4-butanediol.
        4,000원
        2974.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, we investigate the countermeasure of Product Liability through existing research or books for reference about PL and ISO 9001:2000 quality management system. And we analyze relation between PL system and ISO 9001:2000 Quality Management
        4,000원
        2975.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        피리디니움 (pyridunium) 그룹을 포함한 음이온교환막의 제조 및 전기화학적 특성 평가를 수행하였다. 실험 결과, 제조된 피리디니움 음이온교환막은 상용막과 대등한 전기저항 (3.0 Xicm2>, in 0.5 mol dm-3 NaCl) 및 높은 이온선택도 (Cl- 이온수송수 약 0.97)의 우수한 전기화학적 특성을 나타내었다. 또한 피리니디움 그룹을 함유한 음이온교환막에서의 물분해는 상용막 (AM-1, Tokuyama Corp., Japan)에 비해 동일한 전류밀도 하에서 약 100배 내지 1000배 가량 낮게 측정되었는데 이는 4차 아로마틱 피리디니움 그룹의 공명효과 (resonance effect)가 이온교환기의 분자구조적 안정성에 영향을 미쳤기 때문으로 사료되었다. 또한 피리디니움 음이온교환막의 전기투석 특성이 semi-pilot 스케일에서 평가되었다.
        4,000원
        2976.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Poly(ether ether ketone)(PEEK)를 황산을 사용하여 설폰화시킨 후 폴리설폰과 다양한 조성으로 혼합하여 블렌드 고분자 전해질 막을 제조하였고 조성의 변화에 따른 메탄을 투과도, 수소이온전도도, 그리고 이온교환용량의 변화를 측정하였다. 폴리설폰의 경우 이온전도도는 낮은 반면에 메탄올에 대한 저항은 우수하였다. 그러나, 설폰화된 PEEK의 양이 증가함에 따라 메탄을 투과도와 수소이온전도도가 함께 증가하였다. 이온전도도와 메탄을 투과도의 비로부터 폴리설폰의 양이 20%일 때 가장 좋은 선택성을 가지는 것을 알 수 있었다.
        4,000원
        2977.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        건강 기능성과 기호성, 간편성을 갖는 건강차를 개발하기 위하여 4년생 인삼엽을 7월과 8월에 각각 채엽하고 이를 재료로 하여 건조법 (DRT), 숙성법(AGT), 열처리법 (HPT)등의 3가지 방법으로 인삼엽차를 제조하고 인삼제품의 품질 지표인 조사포닌 함량과 조성을 조사한 결과는 다음과 같다. 1. 인삼엽차의 조사포닌 함량은 제조 방법 중 HPT 가 18.72 ~ 18.82%로 가장 높았으며 AGT는 18.24 ~ 18.29%, DRT는 17.02 ~ 17.17%순이었고 채엽시기별 함량 차이는 거의 나타나지 않았다. 2. 인삼엽차의 protopanaxadiol(PD), protopanaxatriol (PT)계 사포닌의 함량비 (PD/PT)는 제조 방법 중 DRT가 1.11 ~ 1.13, HPT 1.09 ~ 1.12 이었고, AGT는 0.92 ~ 1.02ft 다소 낮은 결과를 나타내었다. 또한 채엽시기별 함량비는 유사하였다. 4. 인삼엽차의 5분간 열탕침출액의 조사포닌 함량은 7월엽 제품, HPT가 각각 15.88%, 16.88%로 가장 높았고 ginsenoside 함량은 -Re, -Rd, -Rg_1, -Rb_2, -Rc순이었다. 알콜로 8시간 환류 추출한 총 사포닌과 5분간 열탕 침출액 중 조사포닌 함량을 비교한 조사포닌 침출율은 81.74 ~ 84.38%로서 7월엽 제품, HPT가 84.38%로 가장 높았고 ginsenoside 침출율은 다소 낮은 78.00 ~ 88.13%를 나타내었다. 또한 30분간 침출액의 침출율은 88.01 ~ 92.31%로 5분간 침출율보다 7월엽 제품은 10 ~ 135, 8월엽 제품은 약 20% 증가하였고, ginsenoside 침출율은 유사한 경향을 나타내었다.
        4,000원
        2978.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We studied on the preparation and evaluation of O/W type microemulsion containing "wax, liquid paraffine and quaternary ammonium salt". And also it was obtained to stability of microemulsions by mono ethylene glycol(MEG) addition. The microemulsions were generally prepared at 96~97℃ by the phase inversion method. We used polyoxyethylene(20) sorbitan monooleate(POE(20)SMO) and distearyl dimethyl ammonium chloride(D.D.A.C.) as the emulsifiers at microemulsion preparation. From the results, we could get best condition for microemulsion preparation, in case of oil phase, montanic ester wax ; 1.1wt%, paraffine wax ; 1.1wt%, liquid paraffine ; 3.1wt%, propylene glycol ; 0.6wt% and ethylene glycol monobutyl ether ; 0.6wt%, when the ratio(wt%) of D.D.A.C. and POE(20)SMO were 2 : 3. And also we could obtained that the distributed particle size of the final microemulsions were about 8±1.5nm and the mean particle size was 7±0.5nm. We got following results from final microemulsions that the percent of transmittance; 96~98% at 700nm. And the microemulsion blended with MEG of 5~15wt% showed smaller particle size and more stable distribution than non-containing MEG.
        4,000원
        2979.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The core-shell latex particles were prepared by sequential emulsion polymerization of alkyl methacrylate and styrene(ST) by using an water-soluble initiator(APS) after preparing monomer pre-emulsion in the presence of an anionic surfactant(SDBS). In organic/organic core-shell polymerization, the pre-emulsion method, which minimized required quantity of sulfactant, has been used to increase the conversion rate and the stability of core-shell latex particles as well as to reduce the formation of secondary particle that cause problems of soap-free emulsion during shell polymerization. We used several methods to observe the core-shell structure. The core-shell structure was studied by measuring pH change during hydrolysis by NaOH, glass transition temperature(Tg) by differential scanning calorimeter(DSC), morphology of latex by transmission electron microscope(TEM) and change of particle size and distribution by a particle analyzer.
        4,000원
        2980.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acidic degreasing agent(AADA) was prepared by blending sorbitol, Newpol PE-68, Na-dioctyl sulfosuccinate, Tetronix T-70l, MJU-100A, n-octanoic acid, and phosphoric acid, The physical properties of AADA tested with aluminum specimen showed the following results ; when 3wt% AADA-5 was performed at 70℃, the degreasing rate was 95% which is comparitively good, and the percentage of etching was 0.277% which was found to be less than that of commercialized product. when 20wt% of AADA-5 was added at 65℃, the percentage of derusting was 91% and the good defoaming effect proved by following low foaming power tests respectively : Ross and Miles, and Ross and Clark methods.
        4,000원