• Journal of Magnetics
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• v.16 no.4
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• pp.417-422
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• 2011

This paper presents the characteristics of PM eddy current loss and harmonic iron loss for PM step-skewed Interior Permanent Magnet Synchronous Motor (IPMSM) with concentrated windings and multi-layered PM under the running condition of maximum torque per ampere (MTPA) and flux-weakening control. In particular, PM eddy current loss and harmonic iron loss in IPMSM have been numerically computed with three-dimensional Finite Element Analysis (3D FEA), whereby IPMSM with concentrated windings and multi-layered PM has been designed to identify the optimized skew angle contributing to the reduced PM eddy current loss and torque ripples, while maintaining the required average torque. Furthermore, numerical investigation on PM eddy current loss and iron loss at MTPA and flux-weakening control has been carried-out in terms of PM step-skew.

• Journal of Magnetics
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• v.18 no.2
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• pp.216-219
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• 2013

In this paper, the influence of inverter switching harmonics on iron loss and PM loss of Permanent Magnet Synchronous Motor (PMSM) is numerically investigated by Finite Element Method (FEM). In particular, nonlinear FEM is applied for a multi-layered PM Synchronous Motors (PMSMs), Interior buried PMSM (IPMSM) and PM assisted Synchronous Reluctance Motor (PMa-SynRM), which are adoptively designed and compared for Electric Vehicle (EV) propulsion. In particular, iron loss and PM eddy-current loss under the real current waveform including the carrier harmonics from inverter switching are numerically analyzed with nonlinear FEM by considering the skewed stator structure employed for minimizing spatial harmonics.

• Korean Journal of Community Nutrition
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• v.3 no.1
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• pp.12-20
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• 1998

In this study, the food intake, feces and urine of 14 primary school age boys and girls were collected and intake and excretion of iron and zinc were measured. The boys and girls were 8-12 years old and measurement continued for four weeks during which they maintained their normal living pattern. Each boy's and girl's daily intake and excretion of iron and zinc were measured and apparent digestibility and balance were also calculated. The results are as follows. Mean daily intake of iron was $14.9\pm{0.6mg}$ for the boys and $12.4\pm{0.5mg}$ for the girls. Mean daily intake of zinc was $11.8\pm{1.2mg}$ for the boys and $11.5\pm{0.4mg}$ for the girls. Mean daily fecal loss and apparent digestibility of iron was $6.1\pm{0.3mg}$ and $58.8\pm{2.0%}$ for the boys and $6.8\pm{0.1mg}$ and $44.1\pm{2.0%}$ for the girls. Mean daily fecal loss and apparent digestibility of zinc was $9.3\pm{0.2mg}$ and $14.4\pm{5.1%}$ for the boys and $9.7\pm{0.4mg}$ and $14.3\pm{4.3%}$ for the girls. Mean daily urinary loss of iron was $1.1\pm{0.1mg}$ and showed the positive balance of $7.86\pm{0.6mg}$ for the boys and $0.5\pm{0.1mg}$ and showed the positive balance of $5.14\pm{0.4mg}$ for the girls. Mean daily urinary loss of zinc was $0.5\pm{0.1mg}$ and showed the positive balance of $1.03\pm{0.6mg}$ for the girls.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.10
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• pp.511-520
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• 2006

Recently, more attention has been paid to the development of high-speed permanent magnet (PM) synchronous motors, since they are conductive to high efficiency, high power density, small size, and low weight. In high-speed PM machines, core loss and windage loss form a larger proportion of the total losses than usual in conventional mid- or low speed machines. This article deals with the analysis on the core loss and windage loss in PM synchronous motor for high-speed application. Using the data information from a manufacturer and non-linear curve fitting, this paper investigates the magnetic behavior and its core losses in the stator core using the electrical steels. And, the windage loss is calculated according to the variation of the rotational speed, motor inner pressure and temperature.

• Journal of Magnetics
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• v.18 no.3
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• pp.268-275
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• 2013

This paper shows the characteristics of performance for interior permanent magnet machine (IPM) considering driving conditions such as maximum torque per ampere (MTPA) and flux-weakening control especially in terms of harmonic loss. In particular, based on finite element analysis (FEA), permanent magnet (PM) eddycurrent loss and the harmonic iron loss have been computed where the models have been intentionally designed to identify the effects of pole-slot combinations on the loss while maintaining the required power for electric vehicle. From the analysis results, it was shown that the rotor iron loss and PM eddy-current loss of machine employing fractional slot winding are extremely large at load condition. Furthermore, it was revealed that the harmonic iron loss at high-speed operation is mainly distributed over stator teeth and rotor surface, which may aggravate cooling system of the rotor structure in the vehicle.

• Journal of Nutrition and Health
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• v.28 no.8
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• pp.749-758
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• 1995

In this study, the food intake, feces and urine of 16 primary school age boys and girls were collected and intake and excretion of sodium and calcium were measured. The boys and girls were 8-12 years old and measurement continued for four weeks during which they maintained their normal living pattern and body weight. Each boy's and girl's daily intake and excretion of sodium and calcium were measured and apparent digestibility and balance were also studied. The results were as follows. 1) Mean daily intake of sodium was 8.52$\pm$0.38g for the boys and 7.31$\pm$0.44g for the girls. The mean value in males was significantly higher than that in females(p<0.05). Mean daily in take of calcium was 411.0$\pm$16.0mg for the boys and 356.5$\pm$15.4mg for the girls. The mean value in males was significantly higher than that in females(p<0.01). 2) Mean daily fecal loss and apparent digestibility of sodium was 0.32$\pm$0.04g and 96% for the boys and 0.52$\pm$0.07g and 93% for the girls. The fecal loss mean value in males was significantly lower than that in females(p<0.05). Mean daily fecal loss and apparent digestibility of calcium was 299.8$\pm$8.3mg and 29% for the boys and 194.1$\pm$14.3mg and 46% for the girls. The fecal loss mean value in males was significantly higer than that in females(p<0.01). 3) Mean daily urinary loss of sodium was 6.55$\pm$0.50g and showed the positive balance of 1.65g for the boys and 5.67$\pm$0.20g and showed the positive balance of 1.12g for the girls. The urinary loss mean values of the two groups were not significantly different. Mean daily urinary loss of calcium was 42.8$\pm$5.1mg and showed the positive balance of 79.4mg for the boys and 25.0$\pm$1.64mg and showed the positive balance of 137.4mg for the girls. The urinary loss mean value in males was significantly higer than that in females(p<0.01).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.571-577
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• 2008

Introduction: Possible etiologic factors associated with bone loss around implants after implantation are surgical trauma, occlusal overload, periimplantitis, presence of micro gap and the formation of biologic distances. Tarnow et al. observed that the crestal bone loss was greater when the distance between the implants was <3mm than when the implants were ${\geq}\;3mm$ apart. The aim of this study was to evaluate the influence of different interimplant distance on marginal bone and crestal bone resorption in the beagle dogs. Materials and methods: The mandibular premolars of 5 dogs were extracted bilaterally. After 12 weeks of healing, each dog received 7 implants. On each side, implants were separated by 2mm (Group 1) and by 5mm (Group 2). After 16 weeks of healing, the dogs were sacrificed. Marginal bone loss was determined through linear measurements made between the implant-abutment junctions and the most coronal portions of the bone in contact with the implant surface. A line was drawn uniting the implant-abutment junctions of the adjacent implants, and a linear measurement was made at the midpoint in the direction of the most coronal peak of the interimplant bone crest to determine the crestal bone loss. Both of them was measured radiologically and histologically. Result and conclusion: In radiological analysis, the mean of marginal bone loss was $1.26{\pm}0.14mm$ for group 1 and $1.23{\pm}0.34mm$ for group 2, the mean of crestal bone loss was $1.10{\pm}0.14mm$ for group 1 and $1.02{\pm}0.30mm$ for group 2. The results were not statistically significant between 2 groups. In histological analysis, the mean of marginal bone loss was $1.63{\pm}0.48mm$ for group 1 and $1.62{\pm}0.50mm$ for group 2, the mean of crestal bone loss was $1.23{\pm}0.35mm$ for group 1 and $1.15{\pm}0.39mm$ for group 2. The differences were also not statistically significant. The clinical significance of this result is that the increase in the crestal bone loss results in the increase in the distance between the base of the interproximal contact of the crowns and the bone crest, and this determines if papilla will be present or absent between implants. Considering this fact, keeping up sufficient interimplant distance is important to minimize crestal bone loss.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.9
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• pp.792-797
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• 2013

This paper has derived the conversion loss according to the synchronized condition between the transmitted and locally generated spreading signals for the civil global positioning system (GPS) receiver in the heavy wideband Gaussian noise environments. From this, the outputs of the 2-bit nonuniform quantizer, which has the minimum conversion loss, is set to ${\pm}1$ and ${\pm}2$, while the quantization step size is approximated to the jamming-to-signal power ratio.

• The Korean Journal of Physiology
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• v.7 no.1
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• pp.41-47
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• 1973

$Na^{+}$ balance was studied in Rana temporaria, which hibenates in fresh water in the winter time. $Na^{+}$ uptake rate, skin $Na^{+}$ loss rate, urinary $Na^{+}$ loss rate and $Na^{+}-K^{+}$ adenosine triphosphatase(ATPase) were measured at two different temperatures $1{\sim}2^{\circ}C\;and\;20{\sim}24^{\circ}C$ respectively. The results obtained were as follows: 1. $Na^{+}$ uptake rates in the frog in an artificial Pond water (APW) were found to be $8.28{\pm}0.73\;and\;2.19{\pm}0.37\;{\mu}Eq/g/day\;at\;20{\sim}24^{\circ}C\;and\;1.0{\sim}2.5^{\circ}$ respectively. 2. $Na^{+}$ loss rate through the frog skin to APW were found to be $4.26{\pm}0.72\;and\;0.93{\pm}0.21\;{\mu}Eq/g/day$ at the same temperatures. 3. Mean rates of urinary $Na^{+}$ loss at $20{\sim}24^{\circ}C\;and\;3{\sim}4^{\circ}C$ were found to be $3.02{\pm}0.73\;and\;0.78{\pm}0.13\;{\mu}Eq/g/day$ respectively. 4. The activities of $Na^{+}-K^{+}$ activated ATPase of frog skin fragments were found to be $258{\pm}39.4\;and\;49.6{\pm}7.1\;{\mu}M\;Pi/g$ protein/hr at $24^{\circ}C\;and\;2^{\circ}C$ respectively. From the above results, it may be concluded that frogs can take up enough $Na^{+}$ through the skin from APW exceeding skin loss Plus urinary loss at $1{\sim}2^{\circ}C$. It is suggested that $Na^{+}$ transport across frog skin is closely related with $Na^+-K^+$ ATPase since $Q_{10}\;of\;Na^{+}$ uptake is much similar to that of the activities of $Na^{+}-K^{+}$ ATPase.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.93-95
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• 2008

Nowadays more attention is paid to the developing high efficiency electrical machines for energy saving and protection of natural resources. In general, the electromagnetic losses appearing in electrical machines are widely classified into copper loss, core loss and rotor loss. Particularly, in permanent magnet (PM) machines, core loss forms a larger portion of the total losses than in another machine. So, satisfactory prediction of core loss at the design or analysis stage of PM machines is essential to active high efficiency and high performance. This paper deals with analysis of magnetic field distribution due to geometry of stator core for magnetic core loss calculation of multi-pole PM synchronous machine.