• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.20-26
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• 2016

The bioelectrical impedance (BI) for the young and the elderly was measured using bioelectrical impedance spectroscopy (BIS). First, while applying a current of $600{\mu}A$ to the foot and hand, BI was measured at 50 frequencies ranging from 5 to 1000 kHz. The BI for young subjects was considerably lower than that for old subjects since young subjects have more lean mass (hydration). The prediction marker was 0.74 for young subjects and 0.78 for old subjects. Second, a Cole-Cole diagram was obtained for young subjects and old subjects, indicating the different characteristic frequencies. At 50 kHz, the average phase angle was $7.8^{\circ}$ for young subjects whereas that was $6.1^{\circ}$ for old subjects. Third, BIVA was analyzed for young subjects and old subjects. The vector length was 210.89 [${\Omega}/m$] for young subjects and 326.12 [${\Omega}/m$] for old subjects. At 50 kHz, the resistance (R/H) and the reactance ($X_C/H$) divided by height were 208.94 [${\Omega}/m$] and 28.68 [${\Omega}/m$] for young subject, and 324.33 [${\Omega}/m$] and 34.09 [${\Omega}/m$] for old subjects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.175-178
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• 1995

Distribution of relaxation time is presented in the Cole-Cole arc diagram with frequency parameter. In the case of estimation of activation energy for main chains, maximum loss frequencies of ${\alpha}$ peaks, f$\sub$m/(${\alpha}$) display curved change according to the WLF type with variations of temperature. Structural change by the filling of filler and degradation by the thermal aging can be estimated from the WLF factors, C$_1$and C$_2$in Log f$\sub$m/-1/T curves which reflect the variations of free volume and thermal expansivity of composites.

• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.227-232
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• 2023

In this study, complex admittance as a function of temperature and frequency was measured to analyze the important relaxation properties of lead scandium niobate, which is physically important, although it is not an environmentally friendly electrical and electronic material, including lead. Lead scandium niobate was synthesized by heat treating the solid oxide, and the conductance, susceptance and capacitance were measured as a function of temperature and frequency from the temperature dependence of the RLC circuit. The relaxation characteristics of lead scandium niobate were found to be affected by contributions such as grain size, grain boundary characteristics, space charge, and dipole arrangement. As the temperature rises, the maximum admittance and susceptance increase in one direction, but the resonance frequency decreases below the transition temperature but increases after the phase transition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.49-54
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• 1978

The cold water mass appeared in offshore of the east coast of Korea in summer season was studied in aspect of chemical oceanography. Such a typical relationship between phosphate and dissolved oxygen as shown in the upwelling regions could not be found in the east coast except around the Kampo coast, southern part of the east coast. It is possible to isolate the North Korean Cold Water from tile proper water of tile Japan Sea by using $\sigma_t-O_2$ diagram. The origin of the cold water mass in offshore of the east coast of Korea in summer is not mainly due to the development of upwelling of the proper water of the Japan Sea but thesouthwardflolvingoftheNorthKoreanCold Water.