• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.92-95
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• 2004

Power transformer is an important apparatus in transforming and delivering the power in a power system. It shows less accident ratio than other system apparatus, but once the accident occurs, it causes long-term operation stoppage and economic loss. It brings high bad spillover effects. Therefore, the role of protective relaying, which is to prevent internal fault a power transformer is highly important. This study proposed advanced algorithm that can clearly determine internal fault of the power transformer and magnetizing inrush, through numerical analysis by using the terminal voltage and input output current.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.6
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• pp.339-349
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• 1988

The simplified simulation technique for the best generation mix is developed and the studied results are described. The best generation mix over study time from the economic point of view can be easily constructed by this technique. Generator maintenance, the operation of pumpgenerator and LNG thermal generator with limited energy are simulated variously, so a role of each generator is also easily evaluated. Through parametric analysis, useful planning guide points are obtained for the best generation mix transition, nuclear power plant construction cost, ruanium cost , oil cost, coal cost and midnight factor in the study case corresponding to real power system size model.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.2
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• pp.75-83
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• 2006

• 대한생식의학회:학술대회논문집
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• 2002.11a
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• pp.87.1-87.1
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• 2002

• 전기의세계
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• v.30 no.8
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• pp.517-524
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• 1981

Thermally stimulated currents have been obtained from five kinds of polymer electrets. The peak current (I$_{m}$) and the peak temperature (T$_{m}$) of the TSC, particularly at PET thermoelectret, were found to depend on the forming field and the forming temperature. From these experimental results, the TSC spectra can be easily explained by the consideration of the disorientation of dipoles related with glass transition temperature. The obtained results can suggest that the forming field and the forming temperature plays an essential role for charge stability in PET thermoelectrets.ets.

• Macromolecular Research
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• v.8 no.2
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• pp.89-94
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• 2000

A semi-interpenetrating network (IPN) was prepared for a temperature-sensitive polymer system composed of sodium alginate and poly (N, N-dimethylaminoethyl methacrylate (DMAEMA)-co-ethyl acrylamide (EAAm)). The role of sodium alginate is to provide crosslinked network and that of poly(DMAEMA-co-EAAm) is to provide temperature responsiveness to the polymer system. Semi-IPN gel shows temperature-induced swelling transition at the same temperature of the lower critical solution temperature of poly(DMAEMA-co-EAAm) and its swelling kinetics is manipulated by the control of crosslinking densitv.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.554-559
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• 1989

The electronic structure, conformational preferences, and rotational barriers have been studied for transition metal indenyl allyl complexes by means of extended Huckel calculations. After geometrical optimization the exo conformation of allyl moiety is favored over the endo. The rotational barrier of indenyl ring in (Indenyl)Mo(CO)_2(Allyl)$ is computed to be 3.8 kcal/mol. Population analysis is applied to account for the conformational preferences and rotational barriers. A series of substituted allyl complexes has been also optimized. It shows steric hindrance plays a crucial role in setting the allyl orientation.

• Bulletin of the Korean Chemical Society
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• v.16 no.7
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• pp.574-577
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• 1995

Solvatochromic effect and hydrogen bonding interaction of NPNOH, NPNO- and NPNOR were investigated. Electronic transition energies of the dyes were plotted against empirical solvent polarity parameters, Taft's π* and Reichardt's ET(30). Good correlations were observed when the excitation energies were plotted against the energy calculated by multiple linear regression method which was developed by Taft. There is an intrinsic difference between betaine for ET(30) polarity scale and the azoderivative, which is derived from the specific hydrogen bond incurred with probe molecules and solvents. The hydrogen bonding plays a very important role for stabilization of an excited state molecule by solvents especially when a solute possesses a negative charge as with NPNO-.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.351-353
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• 1995

The physical origins of anomalous volume effect (Invar effect) and elastic effect (Elinvar effect) are critically examined. We found that, unlike the volume effect, the shear elastic properties are not much influenced by the ferromagnetic transition. This finding shows that the two anomalies originate from different physical origins, thus contradicting the conventional wisdom. We discuss the consequences of this finding in the light of recent experiments.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.397-402
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• 2022

In this short review, we explore the recent progress in metal-based gas-sensing techniques. The strong interaction between the metal films and hydrogen gas can be considered to play a considerably important role in the gas-sensing technique. The physical and chemical reactions in Pd-Pd hydride systems were studied in terms of the phase transition and lattice expansion of the metals. Two types of represented detection, electrical and optical, were introduced and discussed along with their advantages.