• 건축구조
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• v.21 no.6
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• pp.73-75
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• 2014

• 건축구조
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• v.22 no.4
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• pp.61-63
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• 2015

• 건축구조
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• v.21 no.3
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• pp.82-83
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• 2014

• 건축구조
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• v.21 no.4
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• pp.49-51
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• 2014

• 건축구조
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• v.21 no.5
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• pp.83-85
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• 2014

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.877-882
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• 2016

In this paper, a novel CMOS high Q factor 2-port active inductor has been proposed. The proposed circuit is designed by cascading basic gyrator-C structural active inductors and attaching the feedback LC resonance circuit. This LC resonator can compensate parasitic capacitance of transistor and can improve Q factor over wide frequency range. The proposed circuit was fabricated and simulated using 65 nm Samsung RF CMOS process. The fabricated circuit shows inductance of above 2 nH and Q factor higher than 40 in the frequency range of 1~6 GHz.

• Journal of the Korean Geophysical Society
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• v.3 no.3
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• pp.193-200
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• 2000

The attenuation characteristics($Q^{-1}$) are important factors representing the physical properties of the Earth interiors, and are essential for the quantitative prediction of strong ground-motion. Based on 156 earthquakes including 76 single-station record on the seismic station located Deok-jung Ri, southeastern Korea, we made the simultaneous measurement of P and S wave attenuation($Q_P^{-1}\;and\;Q_S^{-1}$) by means of extended coda-normalization method. Estimated $Q_P^{-1}\;and\;Q_S^{-1}$ decreased from $1{\times}10^{-2}\;and\;9{\times}10^{-3}$ at 1.5 Hz to $6{\times}10^{-4}\;and\;5{\times}10^{-4}$ at 24 Hz, respectively. This can be expressed by $Q_P^{-1}=0.01\;f^{-1.07}\;and\;Q_S^{-1}=0.01\;f^{-1.03}$ which indicate strong frequency dependence.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.180-188
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• 2014

This study focused on assessing the solubility and structural characteristics of two types of coenzyme $Q_{10}$ ($CoQ_{10}$) complexes: the $CoQ_{10}$-starch and the $CoQ_{10}$-cyclodextrin complexes. The solubility of $CoQ_{10}$-starch complex increased significantly as the temperature was increased. However, the solubility of $CoQ_{10}$-cyclodextrin complex reached a peak at $37^{\circ}C$, and strong aggregation occurred at $50^{\circ}C$. When the temperature was raised to $80^{\circ}C$, the $CoQ_{10}$-cyclodextrin complex dissociated owing to the weakening of bonds, resulting in $CoQ_{10}$ emerging at the surface of water. Therefore, $CoQ_{10}$-cyclodextrin complexes have lower solubility, due to their reduced heat-stability, than do the $CoQ_{10}$-starch complexes. Structural differences between the two $CoQ_{10}$ complexes were confirmed by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD), and differential scanning calorimeter (DSC). The $CoQ_{10}$-cyclodextrin complex included an isoprenoid chain of $CoQ_{10}$, while the $CoQ_{10}$-starch complex included both the benzoquinone ring and the isoprenoid chain of $CoQ_{10}$. These results suggest that $CoQ_{10}$-starch complexes possess higher heat-stability and solubility than do the $CoQ_{10}$-cyclodextrin complexes.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.14-21
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• 2021

Inner shell material of LNG storage tanks that store ultra-low temperature LNG at -162℃ requires structural integrity assessment of a crack-like defect. From the viewpoint of conventional fracture mechanics, the assessment has mainly performed by single parameter using stress intensity factor K, J-integral and CTOD. However, the stresses in a material of crack tip are not unique caused by constraint loss due to size and geometry of the structure. Various attempts have been made to complement a single parameter fracture mechanics, typically with Q-stress. In this paper, we have performed a two-parameter approach by deriving the Q-stress coupling with J-integral suitable for the evaluation of the crack tip stress field in the non-linear elastic region. A quantitative evaluation of the constraint effect has performed by using the J-Q approach. It was evaluated that the SENB type specimen had a crack ratio of 0.1 to 0.7 and the wide type specimen had a crack ratio of 0.2 to 0.6.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.95-104
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• 2011

In this paper, the metamaterial transmission line (TL) based on the complementary spiral resonators (CSRs) and interdigital structure is presented for reducing the phase noise of the voltage-controlled oscillator (VCO). The metamaterial TL is realized by adopting the array of the CSRs etched on the ground plane and the interdigital transmission line on the signal plane. The interdigital TL on the signal plane has been used to obtain higher Q value than the conventional TL without the interdigital structure. The resonance properties and inherent saturation of Q value of the proposed metamaterial TL have been analyzed by varying the width of the TL on the signal plane, dimensions of the CSRs, current directions between the CSRs, number of the unit cell-pair of the CSRs, and whether or not there is the interdigital structure in this paper. The phase noise and tuning range of the proposed VCO are -127.50~-125.33 dBc/Hz at 100 kHz and 5.744~5.852 GHz.