• Journal of the Korean Society for Heat Treatment
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• v.37 no.2
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• pp.49-57
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• 2024

We investigated the changes in microstructure and surface roughness of the compound layer of GC250D gray cast iron, commonly used in brake discs, during gas nitriding. The gas atmosphere of the nitriding process was controlled with a hydrogen partial pressure of 49.5%, and the process was conducted at a nitriding temperature of 520℃ with various process times. As the nitriding process time of the GC250D material increased, both the depth of hardening and the thickness of the compound layer increased, with a maximum surface hardness of approximately 1265 HV_0.1 was measured. Additionally, the surface roughness increased with the process time. Phase analysis of the compound layer revealed an increase in the proportion of the γ' phase as the nitriding process time increased. Changes in the formation of the compound layer were observed depending on the orientation of graphite within the material, leading to the formation of wedges. Therefore, the increase in surface roughness appears to be attributed to the uneven compounds, the expansion of the compound layer and wedges formed on the surface during the nitriding process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.37-45
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• 2018

An electric vehicle is an environmentally friendly vehicle because there is no exhaust gas, unlike gasoline automobiles. On the other hand, because the electric vehicle is driven by electric power charged in batteries, the distance to go through a single charge depends on the energy density of the batteries. Therefore, a lithium-ion battery with a high energy density is a good candidate for batteries in electric vehicles. Because the electrode is an essential component that governs the efficiency of a lithium-ion battery, the electrode manufacturing process plays a vital role in the entire production process of lithium-ion batteries. In particular, the drying process during the electrode manufacturing process is a critical process that has a significant influence on the performance. This paper proposes an innovative process for improving the efficiency and productivity of the drying process in electrode manufacturing and describe the equipment design method and development results. In particular, the design procedure and development method for enhancing the electrode adhesion power, atmospheric pressure superheated steam drying technology, and drying furnace slimming technologies are presented. As a result, high-speed drying technology was developed for battery electrodes through the world's first turbo dryer technology for mass production using open/integrated atmospheric pressure superheated steam. Compared to the conventional drying process, the drying furnace improved the productivity (Dry Lead Time $0.7min{\rightarrow}0.5min$).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.74-80
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• 2021

This study investigated the process quality level of a K5 gas mask, which recently acquired its operational capability, through statistical process analysis for the mass production stages and their lots. The tensile adhesion strength was the only operating requirement in the manufacturing process of the K5 gas mask. For this purpose, the results of tensile adhesion strength between the lens and facial rubber during the initial and second mass production stages were analyzed using conventional statistical and statistical process analysis methods. The conventional statistical results indicated that the second mass production stage was better than the initial mass production stage. In cases of a control chart and process capability of tensile adhesion strength, the process quality level was also improved by following the mass production stages. The improvement was caused by process stabilization and work skill elevation. These results and methods are expected to be conducted and utilized in the third mass production stage. Moreover, quality improvement of K5 gas mask mass production can be achieved using the Lean 6 sigma procedure, MDAIC (Define, Measure, Analyze, Improve, Control).

• Journal of the Korean Professional Engineers Association
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• v.18 no.2
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• pp.6-15
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• 1985

A new process disregraded the H$_2$SO$_4$ treatment process heretofore in use, was developed and substituted for mineral base engine used oil of homemade SAE-30 grade H.V.I., which was used covering 4,500km, as samples, and the following results in research, was obtained. (1) A good quality of rerefinded base oil was obtained through roughly a course of developed processes of vacuum distillation process, solvent extraction process, neutralization treatment process and clay treatment process. (2) Through vacuum distillation process, the size of fine grains of insoluble colloid carbon that is, colloid carbon which was produced by burning of internal combustion engine oil and fuel, could be brought up and precipitated (3) The insoluble matters and admixtures could be easily dispersed and dissolved by mixing and extracting solvent disregarded the H$_2$SO$_4$ treatment process heretofore in use (4) waste matter heretofore called acid sludge in consequence of the process, did not appear at all. accordingly, the environmental pollution could be removed. (5) The troubles of corrosion to copper strip which was faults of the usual used oil refined products and peculiar offensive odor of the rerefined oil, could be solved through the neutralization process. (6) The yield of rerefined oil obtained through a course of processes was over 86 percent, and it is of practical use, not to speak of commercial value.

• Transactions of Materials Processing
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• v.31 no.5
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• pp.296-301
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• 2022

In this study, influence of the process parameters of the roller leveling process on the straightness of the steel wire was analyzed using numerical analysis. To construct the numerical analysis model, cross-sectional and longitudinal element sizes, which affect the prediction accuracy of longitudinal stress caused by bending deformation of the steel wire, were optimized, and mass scaling that satisfies prediction accuracy while reducing computational time was confirmed. By using the constructed numerical analysis model, the influence of various process parameters such as input direction of the steel wire, initial diameter of the steel wire, back tension and intermesh on the straightness was confirmed. The simulation result shows that the 3^rd and 4^th roller of vertical straightener had a significant influence on vertical shape of the steel wire.

• Clean Technology
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• v.10 no.4
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• pp.189-194
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• 2004

The review of the present status of Korean industries and the establishment of strategic R&D agenda are necessary to improve the innovative technological capabilities of Korea to the top level of the world. Recently, Korean ministry of science and technology (MOST) has selected specific areas to develop national technological innovation system, and prepared national technology roadmap (NTRM). Korean ministry of environment (ME) also has prepared technology roadmap (TRM) to help efficient development of environmental science and technology. The development of eco-friendly process in NTRM and TRM was introduced and reviewed in this study. In addition, strength, weakness, opportunities, and threats (SWOT) analysis of technological capabilities of Korea was performed. The results propose the core role of industry, university, research institute, and government for the development of Korean environmental process technology.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2005.11a
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• pp.21-21
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• 2005

• Resources Recycling
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• v.12 no.6
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• pp.3-7
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• 2003

For the manufacture of iron oxide, the hydro-process and the pyre-process are conventionally used. Both processes use a huge amount of chemicals in reaction which affect the environment harmfully. This paper introduced the new environment friendly processes; the bio-chemical process and the self propagating high temperature synthesis process.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2012.05a
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• pp.207-225
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• 2012

한국이 탈추격에 진입하였으며 이에 대응한 새로운 기술혁신전략이 필요하다고 제기되고 있는데, 본 연구에서는 이를 산업연관표에 기반한 산업별 생산방식 변화 등의 분석을 통하여 확인하며, 산업별 인력 구성의 변화를 중심으로 새로운 기술혁신전략을 모색하였다. 인력양성과 활용의 측면을 중심으로 한 학습과정(leaning process)이 R&D 등 혁신노력과 성공적으로 조응될 때 기대한 혁신성과가 실현될 수 있음을, 28산업분류 수준에서 대학 전공의 일에서의 유용성과 R&D투입간 조응성을 통하여 분석하고, 이러한 사항이 국가수준의 혁신정책에 통합되어야 함을 제시하였다.

• Clean Technology
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• v.5 no.1
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• pp.62-77
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• 1999

Semiconductor industry has rapidly grown because of the need from electronic and computer industries. However the global environmental regulations for various hazardous chemical compounds, which are indispensably used in semiconductor manufacturing process, are getting stronger. The semiconductor industries should develop the cleaner technologies in order to both lead the future world market and avoid the regulations form environmentally developed countries. In this paper, cleaner technologies for semiconductor cleaning processes are surveyed, such as gas phase process, UV process, and plasma process. Advantages and disadvantages of these processes are discussed.