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        검색결과 4,564

        174.
        2023.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, a new type of composite material combined with carbonyl iron, a relatively strong ferromagnetic material, was prepared to overcome the current application limitations of Prussian blue, which is effective in removing radioactive cesium. The surface of the prepared composite was analyzed using SEM and XRD, and it was confirmed that nano-sized Prussian Blue was synthesized on the particle surface. In order to evaluate the cesium removal ability, 0.2 g of the composite prepared for raw cesium aquatic solution at a concentration of 5 μg was added and reacted, resulting in a cesium removal rate of 99.5 %. The complex follows Langmuir’s adsorption model and has a maximum adsorption amount (qe) of 79.3 mg/g. The Central Composite Design (CCD) of the Response Surface Method (RSM) was used to derive the optimal application conditions of the prepared composite. The optimal application conditions achieved using Response optimization appeared at a stirring speed of pH 7, 17.6 RPM. The composite manufactured through this research is a material that overcomes the Prussian Blue limit in powder form and is considered to be excellent economically and environmentally when applied to a cesium removal site.
        4,000원
        175.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Ti-6Al-4V lattice structure is widely used in the aerospace industry owing to its high specific strength, specific stiffness, and energy absorption. The quality, performance, and surface roughness of the additively manufactured parts are significantly dependent on various process parameters. Therefore, it is important to study process parameter optimization for relative density and surface roughness control. Here, the part density and surface roughness are examined according to the hatching space, laser power, and scan rotation during laser-powder bed fusion (LPBF), and the optimal process parameters for LPBF are investigated. It has high density and low surface roughness in the specific process parameter ranges of hatching space (0.06–0.12 mm), laser power (225–325 W), and scan rotation (15°). In addition, to investigate the compressive behavior of the lattice structure, a finite element analysis is performed based on the homogenization method. Finite element analysis using the homogenization method indicates that the number of elements decreases from 437,710 to 27 and the analysis time decreases from 3,360 to 9 s. In addition, to verify the reliability of this method, stress–strain data from the compression test and analysis are compared.
        4,000원
        176.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although the Ti–6Al–4V alloy has been used in the aircraft industry owing to its excellent mechanical properties and low density, the low formability of the alloy hinders broadening its applications. Recently, laser-powder bed fusion (L-PBF) has become a novel process for overcoming the limitations of the alloy (i.e., low formability), owing to the high degree of design freedom for the geometry of products having outstanding performance used in hightech applications. In this study, to investigate the effect of bulk shape on the microstructure and mechanical properties of L-PBFed Ti-6Al-4V alloys, two types of samples are fabricated using L-PBF: thick and thin samples. The thick sample exhibits lower strength and higher ductility than the thin sample owing to the larger grain size and lower residual dislocation density of the thick sample because of the heat input during the L-PBF process.
        4,000원
        177.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because magnets fabricated using Nd-Fe-B exhibit excellent magnetic properties, this novel material is used in various high-tech industries. However, because of the brittleness and low formability of Nd-Fe-B magnets, the design freedom of shapes for improving the performance is limited based on conventional tooling and postprocessing. Laserpowder bed fusion (L-PBF), the most famous additive manufacturing (AM) technique, has recently emerged as a novel process for producing geometrically complex shapes of Nd-Fe-B parts owing to its high precision and good spatial resolution. However, because of the repeated thermal shock applied to the materials during L-PBF, it is difficult to fabricate a dense Nd-Fe-B magnet. In this study, a high-density (>96%) Nd-Fe-B magnet is successfully fabricated by minimizing the thermal residual stress caused by substrate heating during L-PBF.
        4,000원
        178.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To analyze the status and needs of the small- and medium-sized garment manufacturing industry in Busan, this study comprised an online survey of companies and interviews with 14 representatives of the 98 companies. The results are as follows: Approximately 34.7% of the garment manufacturers were located in Geumjeong-gu, Busan. The most common type of work was the contracting factory type. Daily production output was between 100pcs and 300pcs. Production materials comprised 42.9% woven and 24.8% knitted fabrics. Main products were menswear, uniforms, womenswear, casual wear, sports and leisure wear, protective clothes, and children’s clothing. The main clients were uniform companies, main factories, wholesale markets, online shopping malls and promotion companies, exporters, and department stores. As a result of a survey on industrial needs with company representatives, their satisfaction with company employees was 57.2%, and the most important factor when hiring employees was job-related competencies, among which the ability to understand the sewing process was the most necessary. In terms of computer software literacy, illustrations and pattern CAD/CAM are required. They thought industry-university cooperation is crucial for advantage for advantage research and product development, as it allows for the sharing knowledge, resources, and especially human resources. The greatest administrative issue were human resources and funding.
        4,800원