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        검색결과 4,563

        2861.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, various model composite latexes were synthesized using n-butyl acrylate and methyl methacrylate as comonomers by seeded multi-staged emulsion polymerization. Monodispersed model composite latex particles with size of 190 nm and polydispersity index of 1.05, which have various morphology including random copolymer particle, soft-core/hard-shell particle, hard-core/soft shell particle, and gradient-type copolymer particle, homopolymers particles were prepared. The designed morphology of model composite particles were confirmed.
        4,000원
        2862.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PU flame-retardant coatings (APHD) containing phosphorous were prepared by blending of hexamethylene diisocyanate-trimer, white pigment, dispersing agent, flowing agent, and previously prepared benzoic acid modified polyester (APTB) that contains phosphorous. Physical properties of the prepared APHD were examined. With the introduction of BZA (contained in APTB), 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, and in a 45˚ Meckel burner method, shows 1.3~4.0cm2 of char length, 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.
        4,000원
        2863.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        2864.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        2865.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The processes of manufacturing FRP sewage disposal tanks are very dangerous and hazardous jobs for workers because of large size and heavy weight of the tank, toxic fiberglass dust, nasty smell, and dangerous tools such as hand-grinders. This paper introduces an automatic manufacturing system of the FRP sewage disposal tank to enhance the safety of workers. The system consists of 3 components: the FRP body rotation jig, the automatic manhole cutting machine, the automatic sanding processing machine. The safety of workers and working environment are greatly improved, because the dangerous jobs are automatized and the toxic fiberglass dust is automatically collected. Also, the productivity is greatly improved and the cost is reduced.
        4,200원
        2866.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Liquid crystalline phases were formed from acylglutamate; polyglyceryl-10 myristate and glycerine mixture and they were used as a base material for preparing an O/W emulsion. When an oil phase is added into the liquid crystalline phases, it was inserted into the dispersed liquid crystal droplets rather than stayed outside the liquid crystals, which can be known by the fact that the size of liquid crystal droplets increases with the increasing oil phase content. Along with the increase in the droplet size, the complex modulus increases from 100 to 350 pascals and the loss angle decreases from 60 to 24 degrees, from which it can be known that the increase in the internal phase volume results in the increase in the elastic property of oil in liquid crystalline-phases (O/LC). When the water phase was lastly added into the O/LC phase, the emulsification occurred to form a O/W emulsion and the averaged particle size of the O/W emulsion changes from 22.5nm to 538nm with the addition of water phase. The results from the droplet size measurements and stability tests under accelerated conditions such as high temperature show that the obtained O/W emulsion is very consistent with time.
        4,000원
        2867.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        양송이의 관행적 재배방법인 볏짚배지를 방울솜으로 대체하여 고품질 다수확을 하는 몇가지 배지 배합비율에 관한 연구의 결과는 다음과 같다. 1. 하절기에 방울솜을 4,000, 4,500kg, 동절기에는 5,000, 5,500kg을 주재료로 처리하고 첨가재료는 주재료에 대한 비율로 왕겨 4.5%, 계분 50%, 석회 1.5%, 요소 2%, 담배가루 2.5%, 깻묵 5%, 석고 5%를 혼합한 결과, 하절기에는 64.33kg, 동절기에는 65.21kg으로 대조구에 비해 57.2%가 증수되었다 2. 면실피 1.25%, 왕겨 4.5%, 계분 50%, 석회 1.5%, 요소 2%, 담배가루 2.5%, 깻묵 5%, 석고 5%를 혼합한 결과, 하절기에는 61.0kg, 동절기에는 62.3kg으로 대조구에 비해 49.6%가 증수되었다 3. 면실피를 1.25% 혼합한 시험구와 왕겨 대신 볏짚(세단) 2.5%와 면실피 1.25% 혼합여 처리한 결과, 하절기에는 59.0kg, 동절기에는 61.3kg으로 대조구에 비해 49.6%가 증수되었다 4. 하절기에 방울솜과 면실피를 각각 2000kg, 동절기에 방울솜과 면실피를 각각 2500kg으로 처리하고 첨가재료는 주재료에 대한 비율로 왕겨 2.5%, 계분 37.5%, 석회 1.5%, 요소 2%, 담배가루 1.25%, 깻묵 2.5%, 석고 3%를 혼합한 결과, 하절기에는 57.33kg, 동절기에는 58.34kg으로 대조구에 비해 40.4%가 증수되었다.
        4,000원
        2868.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Silver bromide particles from 50 to 200a in diameter are prepared by mixing two microemulsions contaning the precursor salts AgNO3 and KBr. The microemulsions are composed of AOT(bis(2-ethylhexyl) sodium sulfosuccinate), n-heptane and water. The particle diameters are measured on photomicrographs obtained by transmission electron microscopy. The size of the particles is generally larger than that of the water cores. The influence of both the concentration of precursor salts in the water cores of the microemulsoin and the size of these water cores on the size of the particles has been studied.
        4,000원
        2869.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        More than three years have passed since Korean companies introduced Six-Sigma. Each company used a lot of quality improvement tools for years. However, the tools have been taught to the companies with a little understanding of Six sigma tools. Therefore,
        4,000원
        2872.
        2004.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pulsed wire evaporation (PWE) method is known as the promising production-technique for nanopowders. In this study, we developed and modified the previous single wire explosion equipment to the simultaneous two-wire explosion one for the fabrication of alloy or mixture of nano metallic powder. First of all, both the theoretical and empirical background of pulsed wire explosion of single wire were summarized, and compared with our experimental results for Cu and Al single wlre explosion. After then, the simultaneous wire evaporation equipment was designed, constructed, and tested. The current and voltage behavior were well matched between the calculated ones from the circuit equations, and the experimental results from simultaneous explosion of Cu and Al wire.
        4,000원
        2873.
        2004.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanoparticles of iron oxides have been prepared by the levitational gas condensation (LGC) method, and their structural and magnetic properties were studied by XRD, TEM and Mossbauer spectroscopy. Fe clusters were evaporated from a surface of the levitated liquid Fe droplet and then condensed into nanoparticles of iron oxide with particle size of 14 to 30 nm in a chamber filled with mixtures of Ar and gases. It was found that the phase transition from both - and -Fe to , which was evaluated from the results of Mossbauer spectra, strongly depended on the flow rate. As a result, - was synthesized under the flow rate of 0.1(Vmin)0.15, whereas was synthesized under the , flow rate of 0.15(Vmin)0.2.
        4,000원
        2874.
        2004.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, the focus is on the analysis of carbothermal reduction of the titanium-cobalt-oxygen based oxide powder by solid carbon for the optimizing synthesis process of ultra fined TiC/Co composite powder. The titanium-cobalt-oxygen based oxide powder was prepared by the combination of the spray drying and desalting processes using the titanium dioxide powder and cobalt nitrate as the raw materials. The titanium-cobalt-oxygen based oxide powder was mixed with carbon black, and then this mixture was carbothermally reduced under a flowing argon atmosphere. The changes in the phase structure and thermal gravity of the mixture during carbothermal reduction were analysed using XRD and TGA. The synthesized titanium-cobalt-oxygen based oxide powder has a mixture of and . This oxide powder was transformed to a mixed state of titanium car-bide and cobalt by solid carbon through four steps of carbothermal reduction steps with increasing temperature; reduction of to and Co, reduction of , to the magneli phase(, n>3), reduction of the mag-neli phase(, n>3) to the (2n3) phases, and reduction and carburization of the (2n3) phases to titanium carbide.
        4,000원
        2875.
        2004.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The nano-sized Co particles were successfully synthesized by chemical vapor condensation (CVC) process using the precursor of cobalt carbonyl (). The influence of carrier gases on the microstructure and magnetic properties of nanoparticles was investigated by means of XRD, TEM, XPS and VSM. The Co nano-particles with different phases and shapes were synthesized with a change of carrier gas : long string morphologies with coexistence of fcc and hcp structure in Ar carrier gas condition; finer Co core in a mass of cobalt oxide with only fcc structure in He; rod type cobalt oxide phase in Ar+6vol%. The saturation magnetization and coercivity was lower in Co nanoparticles synthesized in He carrier gas, due to their finer size.
        4,000원
        2880.
        2003.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to study the removal efficiency of residual organophosphorus pesticides with process for making Perilla Jangachi. Two organophosphorus pesticides(chlorpyrifos-methyl and fenitrothion) were artificially attached to Perilla leaves. Then Perilla leaves were washed with detergent solution for 1minute and rinsed 2 times each for 1 minutes. After washing with neutral detergent solution, Perilla Jangachi was made with 2 steps of optimal condition. As a pretreatment, when soaked with 2% salt concentration solution for 42hours, the removal rate of residual pesticides was 81.75% of chlorpyrifos-methyl and 76.82% of fenitrothion. When Perilla leaves were steamed for 72 seconds after soaking, it became 88.94% and 82.19%, respectively. Finally, after making optimal Perilla Jangachi with 27% onion contents, removal rate was 89.12% of chlorpyrifos-methyl and 82.76% of fenitrothion. Consequently, it appeared that the process for making Perilla Jangachi effectively removed the residual pesticides of Perilla leaves.
        4,000원