• Korea-Australia Rheology Journal
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• v.19 no.1
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• pp.1-5
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• 2007

By combining ultrasonic energy which is essential for the chain scission of polymer molecules and a multifunctional agent (MFA) having double bonds at its ends, we were able to modify the molecular structure of polycarbonate (PC) from linear to a branched structure during melt processing. The three double bonds in chain ends of MFA were expected to act as sites for trapping macroradicals of PC during the course of ultrasound-assisted mixing process. The transformation of molecular structure of PC was confirmed by the measurements of rheological properties of the modified PC. After the ultrasonic irradiation of PC together with MFA, increase in complex viscosities and shear-thinning behavior were observed. The Cole-Cole plot and measurement of extensional viscosities revealed the characteristic features of branched structure with well-defined extensional behavior which is comparable to that of a commercial branched PC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.908-911
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• 2002

This paper investigates the characteristics of deflection for circular plate that has same supporting condition along the width direction of plate according to the area change of supporting end. For two boundary conditions such as simple supporting and clamping on both ends, this study derives maximum deflection formula of circular plate using differential equation of elastic curve, assuming that a circular plate is a beam with different widths along the longitudinal direction. The deflection formula of circular plate is verified by carrying out finite element analysis with regard to the ratio of length of supporting part to radius of circular plate.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1229-1234
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• 2006

This paper is concerned with the dynamic modeling and controller design for a cylindrical shell equipped with MFC actuators. The dynamic model was derived by using Ravleigh-Ritz method based on Donnel-Mushtari shell theory. The boundary conditions at both ends were assumed to be shear diaphragm. To verify the theoretical results, a cylindrical shell structure made of aluminum was built ana tested by using impact hammer. Experimental results show that there are little discrepancies compared to theoretical results because of the boundary conditions at both ends. The MFC actuators were glued to the cylindrical shell in longitudinal and circumferential directions. The PPF controller were designed for lowest two modes and applied to the MFC actuators. The experimental results show that vibrations can be successfully suppressed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.443-450
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• 2001

The Mixed building structures can be divided into three partition, namely, upper wall, lower frame, and transfer system which link two partitions. The purpose of this study is to investigate the nonlinear response characteristics of structures, as the stories of lower frame of mixed building structures changes. The recorded earthquake ground motions of EI Centro 1940 NS is adopted, and the maximum ground accelerations are adjusted to 55ga1, 110ga1, 220ga1, 330ga1. The conclusions of this study are the following. 1) The responses of model that the story of lower frame is one were different from those of other models. 2) The process of ductility hinge occurrence of member was ends of coupling beam of upper wall and ends of beam of lower frame in 55ga1, bases of shear wall on pit floor in 110ga1, and bases of column of 1F in 220ga1.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.11-16
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• 2002

The differential equations governing free vibrations of the elastic, horizontally curved beams with unsymmetric axis are derived in Cartesian coordinates rather than in polar coordinates, in which the effect of torsional inertia is included. Frequencies are computed numerically for the sinusoidal curved beams with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. The convergent efficiency is highly improved under the newly derived differential equations in Cartesian coordinates. The lowest four natural frequency parameters are reported, with and without torsional inertia, as functions of three non-dimensional system parameters: the horizontal rise to chord length ratio, the span length to chord length ratio, and the slenderness ratio.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.105-110
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• 2007

The differential equations governing free, in-plane vibrations of circular curved beams with elastic springs at beth ends, including the effects of axial deformation, rotatory inertia and shear defamation. are solved numerically using the corresponding boundary conditions. The lowest three natural frequencies are calculated over a wide range of non-dimensional system parameters, the radial, tangential and rotational spring parameters, the subtended angle, the slenderness ratio and the shear parameter.

• Journal of Magnetics
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• v.21 no.1
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• pp.72-77
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• 2016

Although the initial cost of permanent-magnet linear synchronous motors is high owing to the installation of armatures over the full length of the transportation lines, linear motors are useful for transportation systems because of their high speed, acceleration, and deceleration. For these reasons, research into reducing the cost of linear motors is necessary, and a stationary distributed-armature system has been suggested for installing armatures in sections where acceleration and deceleration of the mover are required. However, each armature has ends that significantly increase the cogging force, resulting in the increase in the thrust ripple of the mover. Therefore, in order to improve the thrust ripple of the system, the present study aims to provide auxiliary teeth on both ends of the armature to achieve an optimal design through an analysis of the contribution ratio with respect to factors regarding the design of the experiment and the objective function.

• ETRI Journal
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• v.28 no.5
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• pp.607-614
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• 2006

This paper presents a new class of microstrip slow-wave open-loop resonator filters with reduced size and improved stopband characteristics. A comprehensive treatment of both ends loaded with triangular and rectangular ends is described, leading to the invention of a microstrip slow-wave open-loop resonator. Two-resonator and four-resonator bandpass filters are designed at the operating frequency of about 2 GHz, and a bandwidth of 60 MHz. The size of the slow-wave open-loop resonator is optimized from the standpoint of the unloaded Q-factor. The filters are not only compact in size due to the slow-wave effect, but also have a wider upper stopband resulting from the dispersion effect. The filter designs of this type are described in details. The experimental results are demonstrated and discussed.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1972-1974
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• 2000

In this paper, we made an experiment on fault location of underground cables with travelling wave. The 5C2V coaxial cables of 100, 200m length, connected with discharge gap, are used for simplifying model cable lines of power cable. And 100KHz -2MHz CT and HV probe are installed at one side of the ends. We made travelling pulse in discharge gab and then pulse travelled along the cable to the both ends. Therefore, it is detected in CT and HV probe. Measuring the time difference of the pulse start and arrival, we were able to obtain the distance of pulse travelling. Consequently, our experimental results show the possibility to detect fault location of underground cables with travelling wave.

• The Journal of the Acoustical Society of Korea
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• v.29 no.2E
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• pp.100-106
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• 2010

Multiple-model speech recognizer has been shown to be quite successful in noisy speech recognition. However, its performance has usually been tested using the general speech front-ends which do not incorporate any noise adaptive algorithms. For the accurate evaluation of the effectiveness of the multiple-model frame in noisy speech recognition, we used the state-of-the-art front-ends and compared its performance with the well-known multi-style training method. In addition, we improved the multiple-model speech recognizer by employing N-best reference HMMs for interpolation and using multiple SNR levels for training each of the reference HMM.