• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1424-1430
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• 2013

This paper presents design procedure of the magnetic bearings used for high-speed electric machines and flywheel energy storage systems. Magnetic bearing can be categorized by inner-rotor type and outer-rotor type according to the position of the rotary disc. These two types are applicable based on application environments such as application space, required attraction force, and controllability. Magnetic bearing is generally designed based on the ratio (geometrical coefficient or geometrical efficiency) of pole width to rotor journal radius but proper ratio is only decided by the analysis. This is the difficulty of the magnetic bearing design. In this paper, proper design technology of the inner-rotor type and outer-rotor-type eight pole magnetic bearings is introduced and compared with the FEM analysis results, which verifies the proposed design procedure is suitable to be applied to the design of the magnetic bearings for the industrial applications and flywheel energy storage system.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.530-538
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• 2007

Magnetocardiography (MCG) is a device to measure the magnetic field from the heart. It is a noninvasive device and takes only few minutes to record magnetocardiogram from a subject. In this study, we compared the difference of MCG data recorded from 56 normal subjects in early twenties (28 males and 28 females, mean $age=21.0{\pm}1.6$ years) and 36 elderly subjects (20 males and 16 females, mean $age=61.9{\pm}6.9$ years) for the analysis of the age and gender difference. A total of 24 parameters used in the analysis were derived from QRS complex, R-wave, T-wave, and ST-T period. As a result, seven parameters including maximum current angle and map angle showed the significant difference (p<0.01 and p<0.05, respectively) between young males and young females. Significant difference (p<0.05) between elderly males and elderly females was found from a parameter, pole distance at T-wave peak. In the comparison of age difference, seven parameters regarding current moment, pole distance, and dynamics showed the significant difference between young and elderly males. Eight parameters also showed significant difference (p<0.05) between two younger and elderly female groups. Results showed that parameters regarding current moment, pole distance, and dynamics might be changed when people get older. In conclusion, gender and age difference should be considered when MCG data are analyzed for certain parameters.

• Journal of Power System Engineering
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• v.13 no.3
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• pp.33-39
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• 2009

The aim of this study is to analyze the welds characteristics of the 205 stainless steel pipe for application of street pole material. The welds corrosion behavior of STS 205 pipe in 0.1 N sulphuric acid solution and 5% NaCl solution at room temperature was studied using both salt spray test and potentiodynamic polarization experiment. The morphology and components of corrosion products on surface of STS 205 pipe welds were investigated using SEM/EDX. The tensile strength and yield strength values of STS 205 plate were 715 MPa and 369 MPa respectively. The microvickers hardness values of STS 205 pipe welds were slightly increased than that of STS 304 pipe welds. Corrosion current density($I_{corr.}$) and critical current density($I_{crit.}$) values of STS 205 pipe welds in 3.5% NaCl solution were $1.89{\times}10^{-6}$ $A/cm^2$ and $15.8{\times}10 ^{-6}$ $A/cm^2$. The corrosion resistance of SIS 205 pipe welds was similar to its STS 304 pipe welds. The STS 205 and 304 pipe welds passive films were chromium oxide. Especially, the STS 205 pipe welds showed good corrosion resistance in 0.1 N sulphuric acid. This is attributed to the forming of protective chromium oxide on the surface of STS 205 pipe welds.

• Journal of the Korean Geotechnical Society
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• v.28 no.6
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• pp.5-17
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• 2012

The moment responses of electric pole foundations for a railway were investigated using real-scale load tests. Large overturning moments were applied to two circular rigid piles with a 0.75 m diameter and a 2.5 m embedded depth; the circular rigid piles were installed in an actual railway embankment fill. Two different loading directions-toward the fill slope and toward the track -were applied to evaluate the influence of the fill slope on the moment capacities of the foundations. It was found that the failure of the foundations that were constructed according to Korean railway practices exhibited a sudden overturning pattern without any significant pre-failure displacement. The moment capacity toward the fill slope was less than the moment capacity toward the track by 30%. From the test results, the geometry factor (K), which accounted for the reduction of the moment capacity, due to the fill slope, was 0.7. Moment capacities determined from the load tests were compared with those predicted from three existing design methods, and their applicability was discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.52-58
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• 2008

Ths paper describes the Dual-band switch which was proposed new structure that could improved the specification of broadband and designed by the optimized structure through simulation. The Dual-band switch with 2.4[GHz]/5.8[GHz] that can apply to 802.11a/b/g system that is commercialized present was studied to get a new structure with higher power, high isolation. The transmitter of switch was designed to operate a parallel switching element with stack structure of two FET. The receiver designed to have asymmetry structure that insert series FET in addition to basic serial/parallel FET. SPDT(Single Pole Double Throw) Tx/Rx FET switch is a device that can do switching from a port of input to two port of output. The fabricated SPDT switch has the characteristic of insertion loss of a below -3[dB] form DC to 6[GHz] and the isolation of a below -30D[dB](Rx mode).

• Parasites, Hosts and Diseases
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• v.33 no.3
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• pp.231-234
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• 1995

Anisakid larvae were found from the liver and stomach of the codfish (Notothenia negzecta) caught from the Antarctic Ocean, South Pole, where the Polar Research Center of The Korea Ocean Research and Development Institute is operating- Through observations by scanning electron (SEM) and light microscopy (LM), they were identified as the third stage larvae of Pseunotewnnovo necipiens, a potential agent of human codworm anisakiasis. They measured 25.0-28.5 mm in length, and 0.6-0.8 mm in width. The SEM revealed a prominent boring tooth, three lips, and excretory pore at the anterior end, and a small but prominent mucron at the posterior end. From whole mounts and cross sections of the larvae the ventriculus, intestinal cecum and a Renette cell were found characteristically at the same plane. Raw eating of the codfish caught from the Antarctic Ocean near the South Pole should be avoided so as to prevent human codworm anisakiasis in this area.

• Journal of the Korean GEO-environmental Society
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• v.12 no.4
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• pp.43-51
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• 2011

Many electric poles in the softground have been collapsed due to external load. In this study, 10 types of tests were performed with variation of location, numbers and depths of anchor blocks as well as depth of poles to find horizontal earth pressure through full scale pull-out tests. The horizontal earth pressure increased with embedded depth of electric pole, and earth pressure of lower passive zone decreased. The deeper of anchor block, earth pressure of passive zone becomes less. lateral displacements showed differences depending on location, numbers and depth of poles. The bending is generated in the upper part at the initial load, but it moved to central part as load increased. The maximum horizontal displacement decreased to 1/1.6 at -0.5m depth of anchor block and 1.3m additional laying depth of poles into ground.

• Journal of Veterinary Clinics
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• v.38 no.6
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• pp.285-289
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• 2021

An eight-year-old, 3.4 kg, spayed female poodle dog was referred to Gyeongsang National University Animal Medical Center with obstinate bilateral retroperitoneal subcutaneous abscess. The medical history revealed ovariohysterectomy (OHE), lipoma, and mammary gland tumor excision performed two years ago. The dog presented with left retroperitoneal subcutaneous abscess discharge five months back and was treated by abscess drainage and antibiotics in a local veterinary hospital, but a relapse was reported on discontinuing antibiotics. On physical examination, the dog was febrile (40℃) and both retroperitoneal masses showed typical inflammatory reaction and purulent discharge. On serum chemistry analysis, hyperproteinemia, hyperglobulinemia, and elevated levels of C-reactive protein were observed. Cytologic examination showed degenerative neutrophils and phagocytic macrophages. Radiological examination revealed encapsulated hypoechoic subcutaneous masses in bilateral abdominal flank and the left flank mass was connected with the caudal pole of left kidney through fistula. Based on the diagnostic examination, exploratory celiotomy was recommended and left nephrectomy, and resection of bilateral masses were performed. During procedure, fistula between caudal pole of left kidney and left subcutaneous abscess was detected and suture material was identified. Resected tissue was histologically examined and diagnosed as suppurative abscess caused by the suture material. This case report describes chronic suppurative foreign body reaction including caudal pole of left kidney and bilateral retroperitoneal subcutaneous masses induced by the suture material used in OHE two years ago and the necessity of computed tomography examination to identify character of mass and extent of surgical resection.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.601-603
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• 2002

This paper describes the design optimization of a 8:6 Switched Reluctance Motor(SRM) with the rotor pole inserted barrier. The design is focussed on the minimization of the static torque ripple as maintaining the average torque and the efficiency of the demanded value. The finite element analysis method (FEM) and the optimization algorithm are used to optimize the shape of the rotor pole. By comparing the FEM results of barrier type SRM with these of prototype, it is verified that the barrier type SRM improves the static torque characteristics.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.1
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• pp.1-6
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• 2002

Cogging torque is often a principal source of vibration and acoustic noise in high precision spindle motor applications. In this paper, cogging torque is analytically calculated using energy method to show that Fourier spectra of airgap permeance function and airgap MMF function are the most important design parameters to control cogging torque. To control these functions, stator pole shoe pairing and magnet arc design are proposed to minimize cogging torque. As for optimization technique, genetic algorithm is applied to handle trade-off effects of design parameters. Results show that the proposed method can reduce the cogging torque effectively.