• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.24-25
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• 2016

In this study, the thermal strain of high strength concrete with the compressive strength of 80, 130, 180MPa were measured under 25% of compressive strength loading condition. As results, it is considered that decline of the elastic modulus and shrinkage strain of high strength concrete become grater at the elevated temperatures.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.143-148
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• 1996

Thousand actinomycetes and 50 soil samples were used for the isolation of microorganisms producing yeast cell wall lytic enzymes. Among 493 strains producing large clear zones on autolysed washed yeast (AWY), 117 strains were selected on living yeast cell agar plates. With the method of lytic activity, one strain (St-1702) was selected, which was temporarily identified as Streptomyces eurythermus. The optimal condition for enzyme production of this strain was partially determined as follows: incubation of the strain for 3 days at 30$\circ$C in the medium containing 2% freeze dried yeast cell, 1% glucose, 1% K$_{2}$HPO$_{4}$, 0.01% MgSO$_{4}$'7H$_{2}$O, 0.5% peptone, and 0.2% (NH$_{4}$)$_{2}$CO$_{3}$ with pH 7.0. The protoplast formation of yeast by using the enzyme produced by this strain was compared with commercial enzymes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.10a
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• pp.38-47
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• 1996

Sectional analysis program for plane strain or axisymmetric geometry of aluminum alloy sheet metals was developed. For modeling the anomalous behavior of aluminum alloy, Barlat's strain rate potential and Hill's 1990 non-quadratic yield theory arranged under the plane stress assumption were employed. 2-D rigid-viscoplastic FEM formulation based on the bending-augmented membrane theory was derived, solving simultaneously force equilibrium as well as non-penetration condition. Isotropic hardening law was also assumed for yielding behavior. To verify the validity and availability of the developed program, 2-D stretch/draw forming process for plane strain geometry and cylindrical cup deep drawing process for axisymmetric geometry were simulated.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.294-305
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• 1999

A vision-based surface-strain measurement system has been still improved since the authors devel-oped the first version of it. New algorithms for the subpixel measurement and surface smoothing are introduced to improve the accuracy and precision in the present study. The effects of these algorithms are investigated by error analysis. And the equations required to calculate 3D surface-strain of a shell element are derived from the shape function of a linear solid finite-element. The influences of external factors on the measurement error are also examined, and several trials are made to obtain possible optimal condition which may minimize the error.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.612-617
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• 2014

It is generally known that the automotive road wheel involves the non-proportional multiaxial loading condition, therefore the measuring dynamic stress and strain in driving state is very important to predict an endurance characteristic of the automotive road wheel. In this study, the ultimate driving test using F1 circuit with respect to 2 kinds of velocity conditions have been carried out in order to measure dynamic stress, strain of the wheel and acceleration of a vehicle. Based on the measured results, the characteristics of dynamic stress generation have been analyzed, and factors which have effect on the dynamic stress generation have been studied.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.199-205
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• 2018

Petroleum energy is the major source of the world energy market, and its massive usage, and the corresponding extreme environmental pollution, imposes a serious threat on the ecological cycles. By screening oil-contaminated soil, we isolated, identified, and characterized a novel strain that represents a considerable diesel-degrading potentiality; the Bacillus aryabhattai DA2 strain is registered in the NCBI with the accession number MG571630, and it possesses an efficient tributyrin-degrading capacity. The optimal condition for diesel degradation by DA2 strain was observed at pH between 7-8 and at the temperature of $30^{\circ}C$. The strain is resistant to salt as well as the antibiotics like ampicillin and streptomycin. These results indicate B. aryabhattai is one of the potential candidates for the remediation of the diesel-contaminated sites.

• Journal of Life Science
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• v.6 no.2
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• pp.120-128
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• 1996

In the screening of actinomycetes culture filtrate for inhibitor of adenosine deaminase, a novel inhibitor was found in a cultured broth of strain J-144K. The optimum conditions for the adenosine deaminase inhibitor production from the isolated strain J-144K were evaluated. This strain showed the maximum yield of adenosine deaminase inhibitor when grown at pH 7.0 and 30$\circ$C for 60 hours in the medium of 1.0% dextrose, 0.5% yeast extract, 0.5% peptone and 0.1% KH$_{2}$PO$_{4}$ under the aerobic condition. Through the activated charcoal extraction, methanol fractionation, Dowex 50 H$^{+}$ X-8 ion exchange column chromatography, Dowex CI$^{-}$ X-8 ion exchange column chromatography, and Sephadex G-15 gel filtration procedures, this inhibitor was purified with three materials.

• Fibers and Polymers
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• v.3 no.3
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• pp.120-127
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• 2002

Ever since the ideal forming theory has been developed for process design purposes, application has been limited to sheet forming and, for bulk forming, to two-dimensional steady flow. Here, application for the non-steady case was made under the plane-strain condition. In the ideal flow, material elements deform fellowing the minimum plastic work path (or mostly proportional true strain path) so that the ideal plane-strain flow can be effectively described using the two-dimensional orthogonal convective coordinate system. Besides kinematics, schemes to optimize preform shapes for a prescribed final part shape and also to define the evolution of shapes and frictionless boundary tractions were developed. Discussions include numerical calculations made for a real automotive part under forging.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2871-2882
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• 1994

Two kinds of 4-node plane stress/strain finite elements are presented in this work. They are derived from the modified Hellinger-Reissner variational principle so as to employ the internal incompatible displacement and independent stress fields, or the incompatible displacement and strain fields. The introduced incompatible functions are selected to satisfy the constant strain condition. The elements are evaluated on several problems of bending and material incompressibility with regular and distorted elements. The results show that the new elements perform excellently in the calculation of deformation and stresses.

• Asian Journal of Turfgrass Science
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• v.13 no.4
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• pp.213-222
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• 1999

The toxic effects of four pesticides on the entomopathogenic nematodes. Heterorhabditis bacteriophora NC strain, Steinernema glaseri NC and Dongrae strain were tested by checking the mortality of infective juveniles(Ijs) in aqueous solution of pesticide. Mortality of Ijs was influenced by pesticide and concentration and soaking time. The herbicide alachlor and insecticide fenitrothion were toxic to Ijc of three entomopathogenic nematodes. But, the fungicides mepronil and tolclofos-methyl were nontoxic to Ijs. Tolclofos-methyl showed significantly very week toxicity at 28 days after soaking for S. glaseri NC strain. H. bacteriophora NC strain was more highly sensitive to high temperature condition then were the other nematodes.