• Structural Engineering and Mechanics
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• 제6권7호
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• pp.817-826
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• 1998

A finite element model based on the incremental endochronic theory for flexible pavement materials was developed in this study. Three grid systems with eight-node cubic isoparametric elements, and different loading steps were used to perform the calculations for a specimen of circular cylinder. The uniaxial stress experimental results on an asphalt mixture at $60^{\circ}C$ in SHRP conducted by University of California at Berkeley were used to check the ability of the derived numerical model. Then, the numerical results showed isotropic response and deviatoric response on the specimen in a three dimensional manner, which provided a better understanding for a deformed flexible material under the specified loading conditions.

• 산업기술연구
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• 제22권A호
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• pp.83-87
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• 2002

Many industrial products such as paints, ink and adhesives are composed of the ingredients of a mixture. In mixture experiments, the characteristics of quality(response) depends only on the proportions of the ingredients and does not depend on the total amount of the mixture. This article discusses the constrained mixture experimental design, the data analysis, and the optimum formulation of ingredients based on the two quality characteristics - taste and flavor. It IS shown that efficient designs can be constructed from D-optimal criterion. Special cubic models were selected as the final mixture response surfaces for both reponses. The desirability function was used for the optimization of the two responses.

• 수산해양기술연구
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• 제42권1호
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• pp.44-53
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• 2006

The expansion of near shore aquaculture is feasibility of moving aquaculture facilities into the open ocean. Numerical modeling technique using finite element method was used to enable the optimum design and evaluation of submersible aquaculture cage system. The characteristics of mooring loads response in mooring lines under waves and current and their response amplitude operators were calculated for single and three point mooring configuration at the surface condition and submerged one. The static mooring loads without wave and current loading were similar for both the surface and submerged configuration. It was calculated that three point mooring was more adequate than single point mooring for the mooring configuration of submersible aquaculture cage system. The wave induced response amplitude operators for the single point mooring configuration with the influence of currents were identical to those without the influence of currents.

• 대한의생명과학회지
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• 제13권2호
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• pp.157-160
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• 2007

Endoplasmic reticulum (ER) plays formation of disulfide bonds and proper folding of secretory proteins. Cellular responses to ER stress enhances the stress-activated kinase pathway and the induces a lot of immediate-early genes. Among of them, the early growth response-1 (Egr-1), a transcription factor, which plays an important role in cell growth, development, differentiation, apoptosis and various types of injury. For that reason, we have tested the expression of Egr-1 against ER stress inducible drugs (tunicamycin, DTT, A23187 and BFA) to understand what kind of aspect occurred by ER stresses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.160-162
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• 2008

This paper present a practical method for long-term voltage stability simulation based on a governor-response power flow. Governor-response power flow (GPF) is to model the long-term system response in the interval from 3 to 30 seconds after disturbance. In this paper, it is assumed that the GPF model ran capture the system state before load restoration starts in contingent conditions. This paper discusses the applicability of GPF to long-term simulation for voltage stability analysis and then explains the GPF formulation and the procedure of the proposed simulation. In addition the paper includes the simulation results with the modified New England 39-bus system.

• 한국군사과학기술학회지
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• 제12권4호
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• pp.491-499
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• 2009

The determination of response characteristics for pressure sensors is routinely limited to static calibration against a deadweight pressure standard. The strength of this method is that the deadweight device is a primary standard used to generate precise pressure. Its weakness lies in the assumption that the static and dynamic responses of the sensor in question are equivalent. Differences in sensor response to static and dynamic events, however, can lead to serious measurement errors. Dynamic techniques are required to calibrate pressure sensors measuring dynamic events in milliseconds. In this paper, a dynamic calibration using negative going dynamic pressure is proposed to determine dynamic pressure response for piezoelectric sensors. Sensitivity and linearity of sensor by the dynamic calibration were compared with those by the static calibration. The uncertainty of calibration results and the goodness of fit test of linear regression analysis were presented. The results show that the dynamic calibration is applicable to determine dynamic pressure response for piezoelectric sensors.

• Journal of Mechanical Science and Technology
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• 제19권2호
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• pp.625-633
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• 2005

A finite element vibration analysis of thin-walled cylindrical shells conveying fluid with uniform velocity is presented. The dynamic behavior of thin-walled shell is based on the Sanders' theory and the fluid in cylindrical shell is considered as inviscid and incompressible so that it satisfies the Laplace's equation. A beam-like shell element is used to reduce the number of degrees-of-freedom by restricting to the circumferential modes of cylindrical shell. An estimation of frequency response function of the pipe considering of the coupled effects of the internal fluid is presented. A dynamic coupling condition of the interface between the fluid and the structure is used. The effective thickness of fluid according to circumferential modes is also discussed. The influence of fluid velocity on the frequency response function is illustrated and discussed. The results by this method are compared with published results and those by commercial tools.

• Structural Engineering and Mechanics
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• 제16권2호
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• pp.115-126
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• 2003

A novel finite element model based on the incremental endochronic theory with the effect of temperature was developed in this study to explore the deformed behaviors of a flexible pavement material. Three mesh systems and two loading steps were used in the calculation process for a specimen of three-dimensional circular cylinder. Computational results in the case of an uni-axial compression test for temperatures at $20^{\circ}C$ and at $40^{\circ}C$ were compared with available experimental measurements to verify the ability of developing numerical scheme. The isotropic response and the deviatoric response due to the thermal effect were presented from deformations in different profiles and displacement plots for the entire specimen. The characteristics of changing asphalt concrete material under a specified loading condition might be seen clearly from the numerical results, and might provide an useful information in the field of road engineering.

• 산업기술연구
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• 제34권
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• pp.39-43
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• 2014

This paper represents a highly porous MWCNT film electrode with interconnected open pores and demonstrated the possibility of using an MWCNT network film as the top electrode for polyimide capacitive humidity sensors. Polyimide humidity sensors with MWCNT electrodes exhibited about 6 times faster response than equivalent Cr electrode sensors. This result may be due to their percolated pore structures, which make water molecules accessible to all polyimide surfaces. The much faster response times of MWCNT electrode sensors is attributed to the percolated pore network, which allows more water molecules to be accessible to polyimide surfaces.

• Macromolecular Research
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• 제10권4호
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• pp.215-220
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• 2002

The electrorheological (ER) and dielectric behaviors of the polypyrrole(PPy)-coated poly(ethyl methacrylate)(PEMA) suspensions in mineral oil were investigated. PPy was coated on PEMA particles to enhance the particle polarization, which would lead to the enhanced ER response. Various PPy-coated PEMA particles were synthesized by controlling the oxidant amount during the pyrrole polymerization, and the ER responses of their suspensions were investigated. The ER response initially increases with the oxidant amount, passes through a maximum, and then decreases with the oxidant amount. The initial increase in the ER response with oxidant amounts is due to the enhanced particle polarization with the increased particle surface conductivity. The dielectric properties of the corresponding suspensions support that the ER enhancement arises from the enhanced particle polarization. The decrease in the ER response at large oxidant amounts seems to arise from the increased conduction between the PPy-coated PEMA particles.