• Design & Manufacturing
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• v.16 no.1
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• pp.43-49
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• 2022

As technologies in various industrial fields develop, high-quality parts are required. In the past, precision parts were produced by the contact machining method, but the contact machining method has clear limitations. In order to solve this problem, research on a non-contact processing method has been conducted, and laser processing and electric discharge processing are representative. However, the non-contact method has a problem in that productivity is insufficient, and there is a problem that it takes a lot of time to continuously process microholes. Researchers have developed an electron beam drilling equipment for continuous processing of fine holes, and a vaporization amplification sheet to increase the processing efficiency of the equipment. In this study, a cylindrical vaporization amplification sheet using room temperature curing type silicon was fabricated, and the metal distribution and thickness uniformity of the produced sheet were analyzed. In order to manufacture a cylindrical vaporization amplification sheet, an equipment capable of using centrifugal force was developed, and a sample in which metal powder was evenly distributed and a constant thickness was produced.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.741-746
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• 2022

In this paper, structural analysis was conducted on the base frame for materials of the conveyor system that automatically produces nurungji. The materials of the base frame were selected as SS400, STS304, Al6063-5. Structural analysis performed Von-Mises stress and maximum displacement for 38 hot plates in real situation, and performed weight of distribution force for yield strength, and calculated safety factor. SS400 and STS304 have little displacement, but Al6063-5 is deformed to 0.149mm, which is 2.6 times greater than other materials. However, since the safety factor was calculated as 8.5, it can be applied to the applicable food processing equipment. The weight of the distributed force for the yield strength of the materials was 17.7kN for SS400, 14.7kN for STS304, and 10.2kN for Al6063-T5. When manufacturing other processed foods with a base frame of the same size, a material suitable for the corresponding weight should be selected.

• Steel and Composite Structures
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• v.43 no.1
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• pp.117-127
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• 2022

This study investigates the wave propagation in porous functionally graded (FG) sandwich plates subjected to hygrothermal environments. A new simple three-unknown first-ordershear deformation theory (FSDT) incorporating an integral term is utilized in this paper. Only three unknowns are used to formulate the governing differential equation by applying the Hamilton principle. The FG layer of the sandwich plate is modeled using the power-law function with evenly distributed porosities to represent the defects of the manufacturing process. The plate is subjected to nonlinear hygrothermal changes across the thickness. The effects of the power-law exponent, core to thickness ratios, porosity volume, and the relations between volume fraction and wave properties of porous FG plate under the hygrothermal environment are investigated. The results showed that the waves' phase velocities increase linearly with the waves number in the FGM plate. The porosity of the FG materials plate has a noticeable impact on the phase velocity when considering the high ratios of the core layer. It has a negligible effect on small core layers. Finally, it is observed that changing temperatures and moistures do not influence the relationship between the power law and the phase velocity.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.1037-1045
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• 2022

In this study, nanoscale Al₂O3 ceramic particles were used due its exceptionally high hardness characteristics, chemical stability, and wear resistance properties. These nanoparticles will be used to investigate the optimal process conditions for the electro co-deposition of the Ni-Al₂O₃ composite coatings. A Watts bath electrolytic solution of a controlled composition along with a fixed agitation speed was used for this study. Whereas the current density, the pH value, temperature and concentration of the nano Al₂O₃ particles of the electrolyte were designated as the manipulative variables. The experimental design method was based on the orthogonal array to find the optimum processing parameters for the electro co-deposition of Ni-Al₂O₃ composite coatings. The result of confirmation experimental based on the optimal processing condition through the analysis of variance ; EDX analysis found that the ratio of alumina increased to 8.65 wt.% and subsequently the overall hardness increased to 983 Hv. Specially, alumina were evenly distributed on Nickel matrix and particles were embedded more firmly and finely in Nickel matrix.

• Progress in Superconductivity and Cryogenics
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• v.8 no.2
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• pp.43-45
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• 2006

Recently, the resistive Fault Current Limiter (SFCL) made with Coated Conductor (CC) has been researched with an advanced capability in CC. Current limiting elements must be connected in series in order to fabricate the resistive SFCL having large capacity. By the way, unless the applied voltage in the SFCL is distributed to the elements when the fault occurred, those elements will be critically damaged. Thus simultaneous quench of the elements is an important factor to design the resistive SFCL. In this paper, simultaneous quench characteristics of current limiting module by using BSCCO 2223 were researched before manufacturing the resistive SFCL by using CC. At the first fault stage, the elements generated the resistance at the same time. However, the unequal voltage is applied to the each element in process of time. The method is suggested to solve the problem of the unequal distribution. These experimental results will play an important part in developing for the resistive SFCL by using CC.

• Transactions of Materials Processing
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• v.32 no.3
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• pp.107-113
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• 2023

The importance of dual-fuel engines has increased for reducing CO₂ emissions. However, the low operating temperature of this engine may induce low-temperature corrosion at combustion parts, which reduces the engine service life. To overcome this problem, NiCr38Al4 alloy was developed for valve spindle, but the cost of this alloy is expensive due to its high Cr content. For reducing the manufacturing cost of valve spindle, in the present work, NiCr38Al4 alloy was welded with Nimonic80A alloy by conducting friction welding. The tensile test results show that the strength of friction-welded specimens follows the properties of the lower-strength parent materials, without severe cracks at the interface. The large shear strain and frictional heat from friction welding not only reduce grain size but also induce solute element diffusion at the interfacial region. Because of the low Cr diffusivity compared with Ti, Cr carbides were not observed in the Nimonic80A matrix, while Ti carbides were distributed in both the Nimonic80A and SNCrW matrices.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.987-1001
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• 2021

One of the most critical issues in the dairy industry, alongside the low birth rate and the aging population, is the decrease in demand for milk. In this study, the consumption trends of 12 major dairy products distributed in Korea were predicted using a logistic model, the Gompertz model, and the Bass diffusion model, which are representative S-shaped growth models. The 12 dairy products are fermented milk (liquid type, cream type), butter, milk powder (modified, whole, skim), liquid milk (market, flavored), condensed milk, cheese (natural, processed), and cream. As a result of the analysis, the growth potential of butter, condensed milk, natural cheese, processed cheese, and cream consumption among the 12 dairy products is relatively high, whereas the growth of the remaining dairy product consumption is expected to stagnate or decrease. However, butter and cream are by-products of the skim milk powder manufacturing process. Therefore, even if the consumption of butter and cream grows, it is difficult to increase the demand of domestic milk unless the production of skim milk powder produced from domestic milk is also increased. Therefore, in order to support the domestic dairy industry, policy support should be focused on increasing domestic milk usage for the production of condensed milk, natural cheese, and processed cheese.

• The Journal of Economics, Marketing and Management
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• v.3 no.2
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• pp.9-20
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• 2015

Could blood type provide a key to wellness and even affect our personality? The theory that blood type is linked to personality (and other mental and physical qualities) is popular mainly in Japan, though it has carried over to Taiwan and South Korea. The present study is the result of a scientific research in which the relationship between two important variables, namely blood group a nd group participation, are determined in the research framework. Based on some collected data from manufacturing firms which are accepted firms in Tehran Stock Exchange, and through cluster sampling a sample was selected. 380 questionnaires were distributed to the personnel of production line, of the firms then the reliability and validity of the questionnaires through independence test and average ratio comparison of the two population were examined, and through Pearson's chi-square formula, the relationship between blood group (independent variable) and group participation (dependent variable) were tested, then through Schuprow coefficient, the prioritization of blood groups over group participation was identified and the following results were obtained: people group participation is affected by their personality features which is derived from their temperament, mood, and characteristics. The study also showed that people blood groups has an effect on their group cooperation, and among blood groups, blood group A has the greatest tendency to group participation and then blood group O, AB, B are prioritized respectively.

• Korea Trade Review
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• v.46 no.5
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• pp.153-171
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• 2021

The purpose of this study is to compare and derive the importance of motivating factors for start-up when deciding to start a business in the logistics and trading industries, and to compare, derive, and identify which motivating factors have an important influence on the start-up decision. In this study, 4 high-level factors such as career factors, policy/institutional factors, environmental factors, and economic factors and 12 low-level factors were derived from those four factors. Based on this, a questionnaire was distributed to established and prospective entrepreneurs, and the results were analyzed using the AHP (Analytic Hierarchy Process) technique. Manufacturing companies recognized the individual's capabilities and government support for them as important. Beside, service companies recognized the industrial environment that could generate economic benefits as important. Although there are differences in perception by group, it can be seen that factors that are recognized as important within each group have connectivity and show the same directivity.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.6
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• pp.47-59
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• 2017

Korean Economy has been developed by the Korean Government's Support for the Large-sized Firms. This Government Policy causes the Polarization between Large-sized and Micro-sized Firms Aggravated. Micro-sized Firms are distributed over the Whole Industry Area, and can also cause the Economic Crisis If They are crashed down. Therefore Government Policy for the Micro-sized Manufacturing Industry is very Important Issue. This Paper Focused on the Analysis of Current Status for the Shoes Micro Manufacturing Industry. For the Effective Analysis, This Paper uses the Statistical Data Open to the Public and also conducts the Survey for the Micro-sized Firms in Busan. Statistical Program is used for Analyzing the Collected Data and the Major Findings are as Follows. First, Shoes Industry is led by the Micro and Small & Medium sized Firms rather than the Large-sized. And the Micro-sized Firms are getting the High Rate among the Whole Shoes Industry. Busan is heavily populated Area as the Origin of Shoes Industry. Second, even though Most of the Owner of the Micro-sized Firms have the High Technology Skill Level, Worker's Aging Phenomenon gets Worse and causes the Technology Handing down to the Next Generation Difficult. Third, Because the Factory Facility of the Micro-sized Firms is Dirt and Unstable, the Modernized Manufacturing Infrastructure such as the Apartment Factory Facility is Necessary. Forth, as the Micro-sized Firms which have the Intangible Asset such as Patent is Few, the Government Policy for Encouraging the Patent Application is strongly Needed. Fifth, Entrepreneurship and Collaboration Mind between Micro-sized Firms are Lacked, so Establishment of the Cooperative Union is required. Finally, the Effort for the Systemic Planning for the Management is lacked, and the Introduction of the Management Innovation is strongly needed. The Limitation and Future Research Direction is also discussed.