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        검색결과 10

        2.
        2015.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The possibility of using the chemical precipitation method of up-cycled ammonium paratungstate (APT) was studied and compared with the thermal decomposition method. WO3 particles were synthesized by chemical precipitation method using a 1: 2 weight ratio of APT: Di-water. For thermal decomposition, APT powder was heated for 4h at 600 oC in air atmosphere. The reaction products were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), particle size analyzer (PSA), and field emission-scanning electron microscopy (FE-SEM). Thermogravimetric analysis (TGA) of the upcycled APT allowed for the identification of the sequence of decomposition and reduction reactions that occurred during the heat treatment. TGA data indicated a total weight loss of 10.78% with the reactions completed in 658 oC. The XRD results showed that APT completely decomposed to WO3 by thermal decomposition and chemical precipitation. The particle size of the synthesized WO3 powders by thermal decomposition with 2 h of planetary milling was around 2 μm. During the chemical precipitation process, the particle size of the synthesized WO3 powders showed a round-shape with ~0.6 μm size.
        4,000원
        3.
        2012.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The efficiency tests of automatic positioning transmitter (APT) using satellite on life jacket were carried out to minimize casualties of fishermen and to make system optimization for effective SAR (Search and Rescue) operation. As the result of the tests, average position was equaled on the comparison between SPOT using low earth orbit satellite and DGPS (Differential Global Positining System), but standard deviation of DGPS for latitude and longitude were 66.4% and 46.3% smaller than those of SPOT. The position precision of SPOT was almost two times lower than LGT using geostationary satellite to compare 95% circular error probability. However, the success rate of receiver for SPOT was revealed as 86.5~94.1% on the experiments in the South Sea and the West Sea and it was 4.5 times higher than LGT. Therefore, SPOT is expected to contribute greatly to the rapid rescue of victim.
        4,000원
        6.
        2005.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To maximize a synergy effect in flame-retardancy of flame-retardant coatings, phosphorus and chlorine were introduced in polymer chains. Two-components PU flame-retardant modified polyesters (ABTTC-10C, -20C, -30C) were prepared by curing, at room temperature, of isocyanate (allophanate-trimer) and prepared modified polyesters which contain phosphorus and chlorine. To examine the film properties of the prepared flame-retardant coatings, film specimens were prepared with the prepared coatings. The film properties of ABTTC, ABTTC-10C and ABTTC-20C, which contain 0, 10 and 20wt%, 2,4-dichlorobenzoic acid (2,4-DCBA), respectively, were proved to be good, whereas the film properties of ABTTC-30C, which contains 30wt% 2,4-DCBA, were proved to be a little bit poor. Two kinds of flame retardancy tests, 45˚Meckel burner method and LOI method, were performed. With the 45˚Meckel burner method, three flame-retardant coatings except ABTTC showed less than 3.4 cm of char length, and showed less than 2 seconds of afterflaming and afterglow. From this result, the prepared flame-retardant coatings were proved to have the 1st grade flame retardancy. With the LOI method, the LOI values of the coatings containing more than 10wt% 2,4-DCBA were higher than 30wt%, which means that the coatings possess good flame-retardancy. From these results, it was found that synergistic effect in flame-retardancy was taken place by the introduced phosphorus and chlorine.
        4,200원
        7.
        1994.12 구독 인증기관 무료, 개인회원 유료
        The Purpose of this study was to establish the belter residential environment in Apt. complex. In this study, the management consciousness of exterior space and the degree of satisfaction were investigated and analyzed on the GI-SAN Apt. complex in Taegu city. The data were obtained through the questionnaire survey about the exterior space of Apt. complex and analyzed by the SPSS/PC. The results of this analysis are as follow; The result of the image analysis were the cleanness factor and the arrangement factor, which have great influenced in residents image of exterior space. The dissatisfaction source of the management conditions were owing to the lake of management techniques and the discord of residents. The subject of management in the residents consciousness was the management office. In additionally, the management form by the residents were highly showed the cleaning and weeding. The main issues of their dissatisfaction about the exterior space was the lake of size, quantity of plants and rest space. The place of the most demand on management was investigated the children playground which was regarded to be the most damaged.
        4,800원
        9.
        2013.04 서비스 종료(열람 제한)
        For pile construction of underground extension in the remodeling, existing piling method have limitations. These method can't access the restricted area and construction period must be delayed by many piling steps. To overcome these defects of existing method, SAP method is developed and gained the NET(No.684). Also, SAP method applied in remodeling site of Chung-Dam Dong 00 APT.