• Korean Journal of Materials Research
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• v.34 no.4
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• pp.208-214
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• 2024

To fabricate intermetallic nanoparticles with high oxygen reduction reaction activity, a high-temperature heat treatment of 700 to 1,000 ℃ is required. This heat treatment provides energy sufficient to induce an atomic rearrangement inside the alloy nanoparticles, increasing the mobility of particles, making them structurally unstable and causing a sintering phenomenon where they agglomerate together naturally. These problems cannot be avoided using a typical heat treatment process that only controls the gas atmosphere and temperature. In this study, as a strategy to overcome the limitations of the existing heat treatment process for the fabrication of intermetallic nanoparticles, we propose an interesting approach, to design a catalyst material structure for heat treatment rather than the process itself. In particular, we introduce a technology that first creates an intermetallic compound structure through a primary high-temperature heat treatment using random alloy particles coated with a carbon shell, and then establishes catalytic active sites by etching the carbon shell using a secondary heat treatment process. By using a carbon shell as a template, nanoparticles with an intermetallic structure can be kept very small while effectively controlling the catalytically active area, thereby creating an optimal alloy catalyst structure for fuel cells.

• Membrane Journal
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• v.14 no.3
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• pp.185-191
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• 2004

It summarized about the properties of thermochemical water-splitting iodine-sulfur process that was hydrogen production using the waste heat from the High Temperature Gas-Cooled Reactor (HTGR) recycling the heat of nuclear power. It was mainly explained about the application of membrane separation technique in IS process. Thermochemical water-splitting hydrogen production method using the high temperature nuclear thermal energy could be realized and remained to be solved the investigation subject. And, it is possible for mass-production of hydrogen such as one of the clean energy in future.

• Textile Coloration and Finishing
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• v.28 no.4
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• pp.299-307
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• 2016

In order to clarify the availability of heat treatment for catechu dyeing, effect of color developing by heating process on cotton fabrics dyed with catechu extract was investigated. Dyed fabrics were heated various time(min) at $150^{\circ}C$. The cases of non-mordanting and mordanting were compared, and examined the effect of sodium acetate as an agent to promote the color developing to fabrics. Experiments with after-mordanting method showed that various colors can be obtained using catechu. K/S values of dyed fabrics with Al, Cu, Fe mordant were higher than the case of no mordant. The fabric by Cu mordanting showed 3 times to the case of no mordant. Fabrics dyed with catechu by mordanting lowered $L^*$ value while there was little change in $a^*$, $b^*$ value as the heating process progressed. Therefore, K/S values were increased due to heating process. The effects of adding sodium acetate in dyeing bath on dyed fabrics were shown higher K/S values, and the $L^*$ values were lower than those without sodium acetate according to heating time increase. The result show sodium acetate had a promoting effect on the color developing to the fabrics by heating process, it was very effective.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.104-110
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• 1998

In automotive industries, various processes for the cost reduction have been investigated lively. As one of them, powder metallurgy becomes influential. Compared to other methods used for he manufacture of steel components the Powder metallurgy process is competitive primarily due to the small number of production steps to reach the final geometry and thereby also the energy-efficiency. In this paper, to alter present forging process into powder metallurgy process by which the automotive clutch disc spline hub is manufactured machining process, the mechanical properties of sintered materials is investigated by specimen test. Selecting the 3 kinds of materials-SMF 4040, SMF 9060 and DHP-1, their properties according to heat treatment such as carburizing -tempering and plasma-nitrodizing are compared. By result of specimen test - tensile test, compression ring test, Impacting test, measurment of hardness, and microstructure analysis - we concluded that SMF 9060 and carburizing-tempering heat treatment is an optimal material and heat treatment method for the spline hub. It will be able to reduce manufacturing cost and weight.

• Journal of Oriental Neuropsychiatry
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• v.16 no.2
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• pp.125-133
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• 2005

Object : This paper is designed to inquire into the influence of eating habits on the emotion of modem people. Method : The methodology is used that searches for materials such as books and treatises on the relationship between eating habits and emotion. Result : Meat used for fast food comes from cows that are fed the feed containing growth hormone and antibiotic. Growth hormone extremely supplements fire or yang within the body while antibiotics undermines the process of yin, leading to an accumulation of damp-heat and inflammation of ministerial fire. Additives contained in instant foods also impinge on the process of yin, leading to poor digestion, damp-heat toxins and ministerial fire. Excessive consumption of meat results in incomplete combustion of fat and hinders the formation of essence. Subsequently, ministerial fire becomes hyperactive as a result of the lack of yin energy. Increased meat consumption in the human diet is coupled with unhealthy eating pattern in which people eat too much for dinner and too quickly. Eating too much disturbs digestion, making it slow and incomplete, leading to excess damp-heat conditions, insufficient amount of vital essence and eventually hyperactive ministerial fire. Milk is considered a catalyst of faster growth, making it suitable for calves. Milk intake rapidly increases the balance of yang and eventually cause hyperactivity of ministerial fire. Conclusion : It is estimated that the eating habits of modern people cause the process of yang, making them feel restless, impatient and aggressive.

• International Journal of Contents
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• v.13 no.2
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• pp.21-28
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• 2017

Abnormal data in the manufacturing process makes it difficult to find useful information that can be applied in data management for the manufacturing industry. It causes various problems in the daily process of production. An issue from the abnormal data can be handled by our method that uses big data and visualization. Visualization is a new technology that transforms data representation into a two-dimensional representation. Nowadays, many newly developed technologies provide data analysis, algorithm, optimization, and high efficiency, and they meet user requirements. We propose combined production of the data visualization approach that uses integrative visualization of sources of abnormal pattern analysis results. The perceived idea of the proposed approach can solve the problem as it also works for big data. It can also improve the performance and understanding by using visualization and solving issues that occur in the manufacturing process with a calendar heat map.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.5
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• pp.303-308
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• 2000

The ring gears of automobile parts are manufactured generally process chart of which is as follows : forging ${\rightarrow}$ annealing or normalizing ${\rightarrow}$ rough machining ${\rightarrow}$ hardening(Quenching-Tempering or carburizing process) ${\rightarrow}$ finish machining. Isothermal annealing process after forging is most effective in the side of improvment of machinability. On this study we selected two kinds of steel;SCM415, SCM435 of most universal and investigated microstructures to find out most suitable condition of heat treatment in proportion continuous cooling and isothermal annealing. As the cooling rate is $5^{\circ}C$ per minute in continuous cooling process, martensite and bainite are coexisted with ferrite and pearlite in SCM435 steel. If the cooling rate is slower than $5^{\circ}C$ per minute, microstructure were only ferrite and pearlite but formation of band structure can't be avoid. On the other hand, microstructure is only ferrite and pearlite regardless of cooling rate because carbon content of SCM415 steel is low. Moreover formation of band structure isn't exposed by faster cooling rate. Most optimal temperature of the isothermal annealing is from $650^{\circ}C$ to $680^{\circ}C$ in SCM435 steel. When holding time is 60 minute with $650^{\circ}C$, the identical ferrite and pearlite microstructures can be obtained.

• Journal of the Korean Society for Heat Treatment
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• v.9 no.2
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• pp.147-158
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• 1996

Generally, analytical consideration on the behaviour of metallic structures during quenching process, and analysis on the thermal stress and deformation after heat treatment are very important in presumption of crack and distorsion of quenched material. In this study a set of constitute equations relevant to the analysis of thermo elasto-viscoplastic materials with strain hysteresis during quenching process way presented on the basis of contimuum thermo-dynamics mechanics. The thermal stresses were numerically calculated by finite element technique of weighted residual method and the principle of virtual work. In the calculation process, the temperature depandency of physical and mechaniclal properties of the material in consideration. On the distribution of elasto-viscoplastic thermal stresses according to radial direction, axial and tangential stress are tensile stress(50MPa, 1.5GPa and 300MPa) in surface and compressive stress(-1.2GPa, -1.14GPa and -750MPa) in the inner part on the other hand, radial stress is tensile stress(900MPa) in area of analysis. According to axial direction, tangential stress gradients are average 60MPa/mm on the whole. The reversion of stress takes place at 11.5 to 16.8mm from the center in area of analysing.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.2
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• pp.100-108
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• 1995

Heat transfer plays a critical role in determining interface location and shape in ZMR process, which is used for the fabrication of silicon - on - insulator structure. In this work, the two - dimensional pseudo - steady - state ZMR model has been developed that can simulate the heat transfer process during ZMR process. It contains the radiation, convection and conduction heat transfer and determines the interface shapes. Numerical solutions from the model include flow field in the molten zone, temperature field in the full SOl structure and the location of solid/liquid interface in the silicon thin film and silicon substrate. We examined the effects of the various system parameters on the temperature profiles and the interface shape.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.60-66
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• 2020

In order to improve fatigue life of transmission gear carburizing is normally used. Carburizing is a very good process to achieve low cost and high performance. The machined gears are heated up to carburizing temperature and then cooled rapidly in an oil bath to produce high surface hardness. The gears may undergo excessive thermal distortion during heating and rapid cooling. In order to predict the distortion during heating and rapid cooling, a coupled thermo-mechanical simulation is needed. In the current research, the simulation of heating and cooling was performed. The results show that the thermal distortion and the residual stresses are well predicted by the coupled simulation. In addition, induction heating and rapid cooling simulation is carried out to predict the thermal distortion. The amount of distortion is compared. It is shown that induction heating is very effective to reduce thermal distortion.