• Transactions of Materials Processing
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• v.7 no.3
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• pp.282-290
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• 1998

In bulk metal forming processes prediction of tool life is very important for saving production cost and achieving good material properties. Generally the service life of tools in metal forming process is limited to a large extent by wear, fracture and plastic deformation of tools. In case of hot and warm forging processes tool life depends on wear over 70%. In this study finite element analyses are con-ducted to warm and hot forging by adopting suggested wear model. By comparison of simulation and eal profile of die suggested wear model. By comparison of simulation and real profile of die suggested model is verified.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.16 no.2
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• pp.121-133
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• 2005

We live seeing, touching, or throwing on considerable textile in our life consciously and unconsciously. Since a Korean-style house is a dwelling space in life style of sitting on the floor with ondol(Korean floor heater), use of textile is limited to bedding goods. However, as western life style takes firm root, use of textile for interior design is increasing. As well, as apartments and foreign style houses have gotten lodgment since 1980, life style is being changed rapidly. So, textile became required factors in dining space where little textile existed. Through literature, history of textile is considered and design image concept is created based on the consideration. In addition, the created concept can be applied to various textile design, which can be a good tool to express eating culture of the country as well as the country's image.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.2
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• pp.54-60
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• 1988

This paper presents a study of tool-life equation on cut-off test by the statistical approach, referred to as response surface methodology instead of a conventional one-variable at a time method. It is the merit of response surface methodology that the test time is reduced to minimize the size and accurate analysis can be done. The reliability of such an equation can also be estimated. Two independent variables, cutting speed and feed rate, were investigated. A first order modeling equation is presented in this project. The results of this study are as follows that tool-life in cut-off operation is affected by cutting speed more than feed, and first order tool-life predicting equations are in good agreement with experimental results.

• Proceedings of the Korea Hospitality Industry Research Society Conference
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• 2005.11a
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• pp.123-133
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• 2005

We live seeing, touching, or throwing on considerable textile in our life consciously and unconsciously. Since a Korean-style house is a dwelling space in life style of sitting on the floor with ondol(Korean floor heater), use of textile is limited to bedding goods. However, as western life style takes firm root, use of textile for interior design is increasing. As well, as apartments and foreign style houses have gotten lodgment since 1980, life style is being changed rapidly. So, textile became required factors in dining space where little textile existed. Through literature, history of textile is considered and design image concept is created based on the consideration. In addition, the created concept can be applied to various textile design, which can be a good tool to express eating culture of the country as well as the country's image.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.243-245
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• 2004

Failure mechanisms of weldments under fatigue loads are interpreted that multiple collinear surface cracks initiating along weld toe propagate under the mutual interaction and coalescence of adjacent two cracks. To estimate fatigue crack propagation life for these weldments, the stress intensity factors of the multiple surface cracks have to be calculated which are influenced strongly by the geometrical complexity of weld toes and attachments. The Ak-factors derived by a parametric study can be introduced for the effective calculation of the stress intensity factors taking into account the geometrical complexity. The fatigue life was estimated by using the Ak-factors and the method considering the propagation mechanisms of the multiple surface cracks. The estimated values showed a good agreement with the measured fatigue life experimentally.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2353-2360
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• 2000

Statistical fatigue properties of metallic materials are increasingly required for reliability design purpose. In this study, static and fatigue tests were conducted and the normal, log-normal, two -parameter Weibull distributions at the 5% significance level are compared using the Kolmogorov-Smirnov goodness-of-fit test. Parameter estimation were compared with experimental results using the maximum likelihood method and least square method. It is found that two-parameter Weibull distribution and maximum likelihood method provide a good fit for static and fatigue life data. Therefore, it is applicable to the static and fatigue life analysis of the spheroidal graphite cast iron. The P-S-N curves were evaluated using log-normal distribution, which showed fatigue life behavior very well.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1668-1677
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• 1993

The objective of this paper is to develop a computational model for predicting the fatigue propagation of collinear multiple surface cracks under constant amplitude and variable amplitude loadings. After examining fatigue crack growth behavior for CT specimens and single surface crack specimens, empirical equations of(11) and(12) are proposed for the prediction of fatigue life in a multiple surface crack geometry. The accuracy of the proposed model is verified using a life prediction computer program. Several case studies were performed to check the accuracy of the proposed model and to verify the usefulness of the developed program. Good agreement is observed between the numerical results based on the proposed model and the published experimental data.

• Korean Medical Education Review
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• v.22 no.3
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• pp.153-162
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• 2020

The aim of modern medicine is to prolong life by fighting death. Doctors have traditionally believed that this was an ethical good deed. The negative connotation surrounding death has led to the avoidance of terminally ill patients. But in a modern society where death is medicalized, doctors have to see dying patients every day and are in a state of guilt from implementing meaningless life-sustaining treatments. Therefore, medical schools should allow medical students to embrace a new perspective through death education. Yonsei University Medical College has implemented death education since 2017 as an optional class for first and second year medical students. Students watch videos related to death once a week for 6 weeks and submit their reflections by e-mail. The professor reads the students' reflections and gives them weekly feedback. Through this coursework, students realize that death is not a medical event, but rather a part of life and completion. The ultimate purpose of death education is to transform blind life-absolutist identity into narrative identity.

• Journal of Embryo Transfer
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• v.23 no.2
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• pp.127-131
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• 2008

Bone marrow (BM) cell harvesting is a crucial element in the isolation of mesenchymal stem cells (MSCs). A simple method for harvesting cat BM cells is described. The results show that a large number of BM cells can rapidly be harvested from the cat by this simple procedure. MSCs prepared by density-gradient method were spindle-shaped morphology with bipolar or polygonal cell bodies and strongly positive for CD9 and CD44 and negative for CD18 and CD45-like. They were capable of differentiation to adipocytic and osteocytic phenotypes when exposed to appropriate induction media. The advantages of this method are its rapidity, simplicity, low invasiveness, and low donor attrition and good outcome.

• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.41-47
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• 2008

This study was conducted to made a grid alloy (Pb-Ca-Sn-Al) which has a temporary composition ratio in order to improve the efficiency of lead acid batteries. The positive activity material made a 3BS(tri-basic lead sulfate; $3PbO{\cdot}PbSO_4{\cdot}H_2O$) by a low temperature curing and it evaluates the plate efficiency through the life cycle testing. The initial current capacity of low temperature curing plate was excellent but the life cycle was not good (S1). As for the S2 plate, however, the initial current capacity and the life cycle were superior.