• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.164-171
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• 2003

The side impact behavior has been investigated when the high strength steel 60TRIP(Transformation Induced Plasticity) is replaced for the conventional low-carbon steel for weight reduction of an auto-body. The side impact analysis was carried out as specified in US-SINCAP with the center pillar and the side sill of the conventional steel or 60TRIP. For accurate impact analyses, the dynamic material properties are adopted with the Johnson-Cook model. The analysis results demonstrate that the penetration of the side members is remarkably reduced when 60TRIP is employed for the center pillar and the side sill replacing the conventional steel. The crashworthiness in the side impact is considerably improved with less penetration of the side members and less acceleration of the opposite floor.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.188-195
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• 1993

Polyelectrolyte complexes and graft copolymers as biomaterials were synthesized from the water soluble cellulose derivatives. Polyelectrolyte complexes have been prepared from carboxymethyl cellulose (CMC) and gelatin. Graft copolymers(Mc-g-AA) were synthesized by grafting acrylic acid (AA) onto methyl cellulose(MC). (Mc-g-AA) and gelatin polyelectrolyte complexes were also prepared. The optimum conditions of each sample were investigated after chemical crosslinking or heat treatment. The preliminary results show that these materials might be interesting for biomedical applications.

• Biomolecules & Therapeutics
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• v.4 no.3
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• pp.291-295
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• 1996

For the screening of antidiabetic effect, this study was carried out to some natural products by measurements of glucose level. MeOH and $CH_2Cl_2$ extracts of natural products were investigated for the effect on glucose level of $N_2$-STZ diabeted Rat. Among the natural products, Dioscorea Rhizoma, Trichosanthes Radix, Nelumbis Semem and Lycii Fructus were shown a remarkable antidiabetic effect.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.147-162
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• 1994

Generally, the forming process of sheet metal is very complex and difficult process because of many variables such as tool geometry, material properties and lubrication. In this view point, the numerical analysis of sheet metal forming process is very difficult. High speed computer is used to model complex sheet metal forming process on a reasonable time scale. The design and development of sheet metal parts in the automotive industry and the need for improved sheet forming process and reduced part development cost have led to the use of computer simulation in tool/die design of sheet metal pressing. HMC(Hyundai Mator Company) has invested to develop programs for analysis of sheet metal forming process with connection of Universities. As a result, several programs were developed. Recently, the commercial software, PAM-STAMP of ESI was installed and is being tried to application of it to the real automotive panels. This article reviews the ongoing activities on development and application of analytical modeling of sheet metal forming at HMC.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.353-354
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• 2009

Tensile deformation behavior with different strain rate was investigated. $Zr_{56.2}Ti_{13.8}Nb_{5.0}Cu_{6.9}Ni_{5.6}Be_{12.5}$ (bulk metallic glass alloy possessed crystal phase which was called $\beta$-phase of dendrite shape, mean size of $20{\sim}30{\mu}m$ and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74Gpa at strain rate of $10^2/s$ and minimum strength was found to be 1.6GPa at $10^{-1}/s$. And then, maximum plastic deformation occurred at the strain rate of $5{\times}10^{-2}/s$ and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.238-241
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• 2007

A roller straightening process is a metal forming technique to improve the geometric quality of products such as straightness and flatness. The geometrical quality can be enhanced by eliminating unnecessary deformations produced during upstream manufacturing processes and minimizing any detrimental internal stress during the roller straightening process. The quality of steel cords can be achieved by the roller straightening depends the process parameters. Such process parameters are the roll intermesh, the roll pitch, the diameter of rolls, the number of rolls and the applied tension. This paper is concerned with the design optimization of the roller straightening process for steel cords with the aid of elasto-plastic finite element analysis. Effects of the process parameters on the straightness of the steel cord are investigated by the finite element analysis. Based on the analysis results, the optimization of the roller straightening process is performed by the response surface method. The roller straightening process using optimum design parameters is carried out in order to confirm the quality of the final products.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.360-363
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• 2007

This paper deals with the dynamic tensile characteristics of the steel sheets for structural members of a train. Train accidents occurs rarely but lead to many casualties and economical loss. Therefore the safety of the train becomes important during the train crash. The dynamic tensile characteristics of the steel sheets are indispensable to analyze the structural crashworthiness. Current research reports the stress-strain curves, fracture elongation and strain rate sensitivities evaluated at the various strain rates especially for SUS304L-ST and SUS304L-LT steel sheets. The results include the difference in the dynamic tensile characteristics of both rolling and transverse directions. Dynamic tensile tests were performed at the strain rates ranging from 0.003/sec to 200/sec using High Speed Material Testing Machine. The materials tested in this research shows interesting behavior at the low strain rates. The strain hardening exponent decreases remarkably while the yield strength increases.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.2
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• pp.12-21
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• 2001

For the purpose of determining characteristics of widely used commercial medical x-ray films, which are used for obtaining the Linac-grams for radiational treatment of cancers, we placed several commercial x-ray films at a fixed distance form the linear accelerator. After varying the exposed amount of radiation step by step, we could obtain a continually increasing density image for each film whose densities were determined by microdensitometer readings. The characteristic curves of the films were obtained by plotting the densities vs. the exposed radiation amounts, and their ${\gamma}$ values were determined. These values can be used to suggest a minimum necessary amount of exposed radiation to get a useful Linac-gram. The measured ${\gamma}$ values of the characteristic curves of the Kodak-DVP/RA-1 film were 1.73 when used 6MV x-ray, 1.70 when used 15MV of intensity. For the Konica-AX film, ${\gamma}$ values were 1.29 and 1.18 respectively. The result suggests that the effective conditions for high resolution of a L-gram be 6 MV of x-ray intensity and about 3 rad of exposed dose on a Kodak-DVP/RA-1 film.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.22-27
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• 2006

As the regulation and assessment program for safety of passengers become stringent, automakers are required to develop lighter and safer vehicles. In order to fulfill both requirements which conflict with each other, automobile and steel companies have proposed the application of AHSS(Advance High Strength Steel) such as DP, TRIP and martensite steel. ULSAB-AVC model is one of the most remarkable reactions to offer solutions with the use of steel for the challenge to improve simultaneously the fuel efficiency, passenger safety, vehicle performance and affordability. This paper is concerned with the crash analysis of ULSAB-AVC model according to the US-SINCAP in order to compare the effectiveness between the model with AHSS and that with conventional steels. The crashworthiness is investigated by comparing the deformed shape of the cabin room, the energy absorption characteristics and the intrusion velocity of a car.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.819-822
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• 2016

This paper proposes an algorithm recognizing finger using a distance graph of a detected finger's contour in a depth image. The distance graph shows angles and Euclidean distances between the center of palm and the hand contour as x and y axis respectively. We can obtain hand gestures from the graph using the fact that the graph has local maximum at the positions of finger tips. After we find the center of mass of the wrist using the fingers is thinner than the palm, we make its angle the orienting angle $0^{\circ}$. The simulation results show that the proposed algorithm can detect hand gestures well regardless of the hand direction.