• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.47-57
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• 2000

Experimental and numerical studies were done to investigate seismic performance of slender shear walls with no boundary confinement that are principal structural members of high0rise bearing wall buildings. 1/3 scale specimens that model the plastic region of long slender shear walls subjected to combined axial load and bending moment were tested to investigate strength, ductility, capacity of energy dissipation, and strain distribution, The experimental results show that the slender shear walls fail due to early crushing in the compressive boundary, and then have very low ductility. The measured maximum compressive strain is 0.0021, much less than 0.004 being commonly used for estimation of ductility. This result indicates that the maximum compressive strain is not a fixed value but is affected by moment gradient along the shear wall height and distance from the neutral axis to the extreme compressive fiber.

• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.48-55
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• 2012

Degradation of performance and life time of a functional material or device thereof is induced, to a great extent, by mass transfer in the material that is driven by various thermodynamic forces imposed intentionally or accidentally during its operation or service. The forces are any gradient of intensive thermodynamic variables, component chemical potentials, electrical potential, temperature, stresses, and the like. This paper reviews electric-field induced degradation phenomena in ionic solid compounds including insulation resistance degradation, crystal shift, microstructural alterations, compositional unmixing, and compound decomposition. Their inner workings are also discussed qualitatively.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.263-269
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• 1986

Membrane proteins of facultatively anaerobic Escherichia coli K12 which was logarithmically grown in aerobiosis and anaerobiosis were compared on 5 to 10% liner gradient gel electrophoresis (Na Dod $SO_4 -PAGE$). Membrane proteins were formed as different patterns between aerobiosis and anaerobiosis. Among them, 91Kdal protein (pbp1a) was not synthesized in aerobiosis and 60Kdal protein (fts cluster), in anaerobiosis. Thereby cells cultured aerobically were differenciated as diversiform cell shape, comparing cells cultured anaerobically and the latter were resistant to penicillin G. Thus it is believed that in facultative anaerobes atmospheric oxygen regulated the synthesis of membrane proteins and even the expression of equivalent genes, and moreover alleviated the resistance to an antibiotic penicillin.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.1-5
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• 2001

A study on the new active type oil-water separation system including the oil-water separation system of magnetic film was carried out. Separation system is composed of several active types of circulating oil separation steps and one magnetic film separation step at final stage. At the magnetic separation step, ferrofluid easily forms a weak magnetic mixture with oil, which is from the water by magnetic field gradient. The vessel has been designed to run at the maximum speed of 25 knots. And two typical forms of SWATH and Catamaran have been studied as a new type of oil recovery vessel.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.459-464
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• 2010

The dynamic propagation of an interface crack between two dissimilar functionally graded layers under anti-plane shear is analyzed using the integral transform method. The properties of the functionally graded layers vary continuously along the thickness. A constant velocity Yoffe-type moving crack is considered. Fourier transform is used to reduce the problem to a dual integral equation, which is then expressed to a Fredholm integral equation of the second kind. Numerical values on the dynamic energy release rate (DERR) are presented. Followings are helpful to increase of the resistance of the interface crack propagation of FGM: a) increase of the gradient of material properties; b) increase of the material properties from the interface to the upper and lower free surface; c) increase of the thickness of FGM layer. The DERR increases or decreases with increase of the crack moving velocity.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.31-42
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• 2012

Urban transit vehicle that uses electrical energy, is faster, safer and energy-efficient public transit than other means. As a Research method, the Matlab/Simulink are used to modeling a regenerative brake-capable train, and actual parameters such as powering and braking characteristics, all kinds of resistance, passenger load, velocity, gradient, radius of curve etc and powering and breaking commands per time or distance are inputted to train's dynamic equation, then a simulation program is made and used to yield train driving pattern and driving time and the amount of driving energy used thereby at auto and manual operation and at all sector.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.155-158
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• 2005

Precipitates, present in most commercial alloys, can have a strong influence on strength and hardening behavior of a single crystal. The effect of thin precipitates on the anisotropy of initial slip resistance and hardening behavior of crystals is modeled in this article. For the convenience of the computational derivation and implementation, the material formulation is given in the unrelated intermediate configuration mapped by the plastic part of the deformation gradient. Material descriptions for the considered two phased aggregates consisting in lattice hardening as well as isotropic hardening and kinematic hardening are suggested. Numerical simulations of various loading cases are presented to discuss and assess the performance of the suggested model.

• Journal of the Korean institute of surface engineering
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• v.36 no.6
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• pp.430-436
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• 2003

The nanoocrystalline Ni-l5W(at.%) coating electrodeposited on the high carbon steel was oxidized at 700 and $800^{\circ}C$ in air, and the resultant oxidation properties were investigated using XRD, EPMA, TGA and TEM. The oxidation resistance of the coating was not so good that most of the coating was oxidized after oxidation at $800^{\circ}C$ for 5 hrs. The oxidation led to the formation of the outer, thin NiO oxide scale and the inner, porous, rather thick ($NiWO_4$＋NiO) mixed layer containing a bit of $WO_2$. During oxidation, substrate elements such as Fe and Cr diffused outwardly toward the coating, according to the concentration gradient.

• Geomechanics and Engineering
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• v.13 no.5
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• pp.793-807
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• 2017

Regularities of temperature variation were determined in points of subgrade of the highway. Measurement of temperature was performed by special sensors, based on the effect of thermal resistance. Regular measurements of temperature were performed for two sections of the highway with asphalt concrete and cement concrete pavements for continuous period from November 2010 to March 2016. Multi-year experimental data, which we obtained, allowed establishing of peculiarities for temperature variation in points of subgrade in time and temperature distribution in the depth for annual cycle. Characteristics were determined for winter period-depth, duration and freezing rate, duration and defreezing rate for pavement and subgrade of the highway.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1156-1166
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• 2004

The shape of plate-fin type heat sink is numerically optimized to acquire the minimum pressure drop under the required temperature rise. In constrained nonlinear optimization problems of thermal/fluid systems, three fundamental difficulties such as high computational cost for function evaluations (i.e., pressure drop and thermal resistance), the absence of design sensitivity information, and the occurrence of numerical noise are commonly confronted. Thus, a sequential approximate optimization (SAO) algorithm has been introduced because it is very hard to obtain the optimal solutions of fluid/thermal systems by means of gradient-based optimization techniques. In this study, the progressive quadratic response surface method (PQRSM) based on the trust region algorithm, which is one of sequential approximate optimization algorithms, is used for optimization and the heat sink is optimized by combining it with the computational fluid dynamics (CFD).