• Corrosion Science and Technology
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• v.4 no.4
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• pp.164-170
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• 2005

Pipelines have the highest capacity and are the safest and the least environmentally disruptive means for transmitting gas or oil. Recently, failures due to corrosion defects have become a major concern in maintaining pipeline integrity. A number of solutions have been developed for the assessment of remaining strength of corroded pipelines. In this paper, a Fitness-For-Purpose(FFP) type limit load solution for corroded city gas pipelines is proposed. For this purpose, a series of burst tests with various types of machined defects were performed. Finite element simulations were carried out to derive an appropriate failure criterion. Based on such solution along with existing solutions, an integrity evaluation program for corroded city gas pipeline, COPAP-CITY, has been developed.

• Journal of Korean Port Research
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• v.5 no.2
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• pp.77-84
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• 1991

This paper is compared with fourier series and least square polynomial fit and interpolation to mechanism stated number in electro-optical distance measuring instrument. Systematic instrumental errors occurring in electro-optical systems include uncertainties in the position of the electrical center of the transmitter, uncertainties in the effective center of the reflectors. frequency drift and instrument nonlinearity. Microwave systems are affected by uncertainties in the electrical centers of the master and remote units and by a phenomenon called group swing or reflection. As the result of this study, mechanism stated number will be used as verification of electro0optical measuring instrument to distance measurement.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.173.2-173.2
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• 2003

Vanilloid receptor I (VR1) is a nonselective cation ion channel placed in the plasma membrane of peripheral sensory neurons that is potential target for analgesia A series of N-4-substituted-benzyl-N'-tert-butylbenzyl thioureas were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor in rat DRG. Their structure-activity relationship in reveals that not only the two oxygens and amide hydrogen of sulfonamido group but also the optimal size of methyl in methanesulfonamido group play an integral role for the antagonistic activity on vanilloid receptor.

• Proceedings of the Korean Biophysical Society Conference
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• 1999.06a
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• pp.41-41
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• 1999

The native forms of some proteins such as inhibitory serpins (serine protease inhibitors) and viral membrane fusion proteins are metastable, which is critical to their functions. To understand the mechanism of how native metastability regulates the inhibitory function of serpins, we characterized stabilizing mutations of $\alpha$$_1$-antitrypsin, a prototype serpin, in which Gly 117 was replaced by a series of larger hydrophobic residues.(omitted)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.141-141
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• 2015

In this study, a series of hydroxyaptite (HAp) are produced on Ti dental implant using electrochemical deposition. Based on the preliminary analysis of the coating structure, composition and morphology. In vitro studies were performed with MC3T3-E1 cell to investigate the effect of biological change on different surface conditions.

• Analytical Science and Technology
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• v.30 no.5
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• pp.262-269
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• 2017

The concentration of natural radioactivity in the sediment of the Geum River was investigated. The river and lake sediment samples were collected at 23 points during September to November, 2015 and March to April, 2015, respectively. The gamma-rays emitted from the $^{226}Ra$ and $^{232}Th$ decay series and $^{40}K$ were measured with a high purity germanium (HPGe) gamma detector. The average radioactivity concentrations of the $^{226}Ra$, $^{232}Th$ decay series and $^{40}K$ for the river sediment was found to be $15.6{\pm}0.6$, $33.8{\pm}1.2$, $789.8{\pm}26.0Bq/kg$, respectively, while for the lake sediment, the concentrations were $17.1{\pm}0.5$, $37.8{\pm}1.1$, $269.4{\pm}9.6Bq/kg$, respectively. Spearman's correlation was conducted to compare the radioactivity concentration and properties of the sediment. The radioactivity concentration of the $^{232}Th$ decay series showed a negative correlation with the particle size of the sediment, and was measured to be higher than the $^{226}Ra$ decay series according to mobility of the radionuclides. The radioactivity concentration of $^{40}K$ showed a negative correlation with organic matter content. The concentration of $^{40}K$ in the lake sediment was lower than that in the river sediment.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.136-136
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• 2003

• Proceedings of the Korean Fiber Society Conference
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• 1997.10a
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• pp.71-75
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• 1997

A new series of water-soluble conjugated aromatic polyimines containing sulfonate groups have been synthesized via polycondensation reaction between diamines and dialdehydes at room temperature. Self-assembled multilayer films consisting each polyimine as a polyanion and poly(diallyldimethylammonium hydrochloride) as a polycation were fabricated successfully by alternate deposition in corresponding aqueous solutions.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.604-607
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• 2003

Three ring type LC compounds substituted with isothiocyanato group and fluoro atoms in phenyl ring were synthesized, and blended with KL-series LC mixtures for TV application of TN and IPS-mode. Clearing temperature of new LC mixtures are shown $10{\sim}35{\square}$ higher than commercial mixtures. And response time was also improved $10{\sim}20%$ faster than conventional LC mixtures.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1208-1216
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• 2014

Mismatch between switching frequency and circuit parameters often occurs in industrial applications, which would lead to instability phenomena. The bifurcation behavior of $V^2$ controlled buck converter is investigated as the pulse width modulation period is varied. Nonlinear behavior is analyzed based on the monodromy matrix of the system. We observed that the stable period-1 orbit was first transformed to the period-2 bifurcation, which subsequently changed to chaos. The mechanism of the series of period-2 bifurcations shows that the characteristic eigenvalue of the monodromy matrix passes through the unit circle along the negative real axis. Resonant parametric perturbation technique has been applied to prevent the onset of instability. Meanwhile, the extended stability region of the converter is obtained. Simulation and experimental prototypes are built, and the corresponding results verify the theoretical analysis.