• Proceedings of the Ginseng society Conference
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• 2004.12a
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• pp.7-11
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• 2004

We previously reported that ginseng inhibited NMDA receptors in cultured hippocampal neurons. Here, we further examined the detailed mechanism of ginseng-mediated inhibition using its main active ingredient, ginsenoside Rg$_3$. Co-application of ginsenoside Rg$_3$ with increasing concentrations of NMDA did not change the EC$_{50}$ of NMDA to the receptor, suggesting ginsenoside Rg$_3$ inhibits NMDA receptors without competing with the NMDA-binding site. Ginsenoside Rg$_3$-mediated inhibition also occurred in a distinctive manner from the well-characterized NMDA receptor open channel blocker, MK-801, However, ginsenoside Rg$_3$ produced its effect in a glycine concentration-dependent manner and shifted the glycine concentration-response curve to the right without changing the maximal response, suggesting the role of ginsenoside Rg$_3$ as a competitive NMDA receptor antagonist. We also demonstrated that ginsenoside Rg$_3$ significantly protected neurons against NMDA insults. Therefore, these results suggest that ginsenoside Rg$_3$ protects NMDA-induced neuronal death via a competitive interaction with the glycine-binding site of NMDA receptors in cultured hippocampal neurons.

• International Journal of High-Rise Buildings
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• v.5 no.3
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• pp.155-165
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• 2016

A much higher level of seismic performance is needed for supertall buildings due to increased demands for their functional continuities and the recognized needs for their continuing emergence in metropolitan areas. This paper analyzes, compares, and contrasts responses recorded during the 2011 Tohoku-oki Earthquake of different supertall buildings featuring conventional and vibration-controlled engineering systems. The superior performance and advantage of the latter are pointed out, and the typical dynamic properties, response characteristics, and effects on the secondary system are discussed. Ongoing efforts to enhance vibration control performance are described, covering the development of specifications, use of performance curves and targeted displacement design, and methods to find appropriate locations of damper installation resulting in a minimized amount of dampers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.676-679
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• 1997

The present paper is concerned with the optimal deslgn that the static spring rate of the fiber-reinforcement composite spring is fitted to that of the steel leaf spring. The thickness and w~dth of springs were selected as deslgn variables. And object functions of the regression model were obtained through the analysis with a common analytic program. After regression coefficients were calculated to get functions of the regression model, optimal solutions were calculated with DOT. E-GlassIEpoxy and CarbonIEpoxy were used as fiber reinforcement materials in the design, which were compared and analyzed with the steel leaf spring. It was found that the static spring rate of the optimal model was almost similar to that of the existing spring.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.715-718
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• 2000

The character of a recombinant bioluminescent bacteria's light emission enables us to monitor toxicity in water, soil and air. In this study, various bioluminescent responses to water samples containing toxic chemicals, such as phenol and mitomycin C, were obtained and analysed through the use of a multi-channel two-stage minibioreactor system. The bioluminescent pattern from each channel can be used as a standard for identifying the degree of toxicity in field samples. When various concentrations of toxic chemicals were injected in a step manner, different bioluminescent patterns were obtained. Also this system showed variation in its bioluminescent pattern as the injection manner was changed, i.e. using a modified version of the bell-curve type injection. In conclusion, the toxicity was shown to be related with the bioluminescent response when using these standard bioluminescent patterns. Comparing this standard with a bioluminescent response from a field sample, we can estimate the degree of which the sample is toxic.

• The KSFM Journal of Fluid Machinery
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• v.17 no.3
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• pp.5-12
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• 2014

This paper presents a design optimization for meridional profile and blade angle ${\theta}$ of a centrifugal compressor with DOE (design of experiments) and RSM (response surface method). Control points of the $3^{rd}$ order Bezier curve are used for design parameters and specific overall efficiency is used as object function. The response surface function shows good agreement with the 3D computational results. Three different optimized designs are proposed and compared with reference design at design point and off-design point. Contours of relative Mach number, static entropy, and total pressure are analyzed for improvement of performance by optimization. Off-design performance analysis is conducted by total pressure and efficiency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.8
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• pp.731-735
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• 2002

Electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure on the poly［4- (fluorocinnamate) phenylmaleimide](PFCPMI) surfaces using a new photodimerization method were investigated. For a new UVLPH (UV linearly polarized during heating) photodimerization method, the photopolymer layers were exposed by linearly polarized UV dichroic polarizer without a specific UV filter during heating at $150^{\circ}C$. The Voltage-transmittance (V-T) curve without backflow bounce in the photoaligned TN-LCD with UV exposure on the PFCPMI surface for 10 min using the UVLPH photodimerization method was observed. For response time measurement, the transmittance characteristics of the photoaligned TN-LCD using the UVLPH photodimerization method on the photopolymer surface was better than that of the photoaligned TN-LCD using the UVLP photodimerization method under a room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.210-213
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• 2004

We synthesized photoalignment material of high thermal resistance with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the photopolymer surface can be obtained. However, the low pretilt angles were obtained below $1^{\circ}$. The Voltage-transmittance (V-T) curve without backflow bounce in the photoaligned TN cell with UV exposure was observed. The response time of photoaligned TN cell was measured about 24 ms. Finally, The photoaligned TN cell has few hysteresis, and shows the residual DC voltage that is less.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.162.6-162
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• 2001

Confocal scanning microscopy (CSM) is an important instrument in a wide variety of imaging applications because of its ability to provide three-dimensional images of thick, volume specimens. The mechanism for two-dimensional beam scanning and optical sectioning has an important roe in CSM as the three-dimensional profiler. This optical sectioning property arises from the use of a point detector, which serves to attenuate the signals from out-of-focus. The intensity profile for the open loop scanning should be matched with its response for the standard. The non-linearity can be minimized with the optical sectioning or the optical probe of the closed loop control. This paper shows the mathematical expression of the light such as the extinction curve in the optical fields of system using AO deflector, the axial/lateral response experimentally when the error sources change, and the methods of optical sectioning. Thorough design of optical sectioner is crucial to the success of CSM in the field ...

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.449-454
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• 2000

A three-parameter model of viscoelastic damper, which has a non-linear spring as an element is incorporated into an oscillator. The behavior of the damper model shows non-linear hysteresis curves which is qualitatively similar to those of real viscoelastic materials. The motion is governed by three-dimensional non-linear dynamical system of equations. The harmonic balance method is applied to get analytic solutions of the system. The frequency-response curves show that multiple solutions co-exist and that the jump phenomena can occur. In addition, it is shown that separate solution branch exists and that it can merge with the primary response curve. Saddle-node bifurcation sets explain the occurences of such non-linear phenomena. A direct time integration of the original equation of motion validifies the use of the harmonic balance method to this sort of problem.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1753-1762
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• 2000

An inverse method is presented to obtain material's flow properties by using small punch test. This procedure employs, as the objective function of inverse analysis, the balance of measured load-di splacement response and calculated one during deformation. In order to guarantee convergence to global minimum, simulated annealing method was adopted to optimize the current objective function. In addition, artificial neural network was used to predict the load-displacement response under given material parameters which is the most time consuming and limits applications of global optimization methods to these kinds of problems. By implementing the simulated annealing for optimization along with calculating load-displacement curve by neural network, material parameters were identified irrespective of initial values within very short time for simulated test data. We also tested the present method for error-containing experimental data and showed that the flow properties of material were well predicted.