• 전기의세계
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• v.29 no.1
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• pp.58-64
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• 1980

In this paper, this objective is to obtain the mathematical model which describes the dynamic characteristics of variable reluctance(VR) step motor, the most important and most widely used motor in practice. In the development of the mathematical model for VR step motor, first the general nonlinear dynamic equations which describe the N-phase VR step motor are derived. These general equations are then applied to the multiple-step type of VR step motor in case, for simplicity, maynetic saturation and core lossess in the iron are neglected. These nonlinear dynamic equations are numerically analysed by the computer simulation, through which the performance characteristics of a step motor undertest are investigated under the various operating conditions.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.1
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• pp.97-104
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• 2015

An electric-motor which uses electric energy to dry laundry in a dryer generates wind by rotating a fan. The roles of electric motor and fan are crucial for drying. To reduce the noises or vibration, their performances should be improved. However, it requires a relatively high cost to redesign them. In this case, redesigning the fan case rather than the motor or the fan would be easier and cheaper. This paper is to apply Taguchi dynamic characteristic concept with the ideal function of energy conversion to redesign the fan case. Not only the increase of the wind power but also the decrease of noise, vibration and the other side effects are resulted.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.1
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• pp.81-87
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• 2017

In order to reduce the weight of the blow motor case and to maintain the strength of the motor joint, the mechanical joining strength is to be predicted. The true stress - true strain curves for finite element analysis were obtained through tensile tests of HGI and DP 780 steel. The mechanical joining strength was predicted through an explicit finite element analysis and the accuracy of the predicted results was verified by actual sample test. The regression equation for predicting the mechanical joining strength to the thickness of the DP 780 steel was derived. The minimum thickness of DP 780(1.2mm), which is equivalent to the joining strength of HGI(2.6mm), was derived from the equation.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.6
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• pp.525-529
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• 2016

In the case of a motor system that converts electrical energy into mechanical energy, the region of the motor and that of the generator coexists. In the case of an escalator, the ascending escalator is operated by the motor, whereas the descending escalator is operated by the generator according to the load. To evaluate the proposed method, this study reduces the power of the ascending escalator up to approximately 35% by sharing the regeneration power of the descending escalator. The loss of transfer power nearly exists in the case of the proposed method. Furthermore, the lifetime of the DC link condenser can be extended because it is connected in parallel, thus leading to a twofold increase in capacity.

• Journal of Pharmacopuncture
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• v.3 no.1
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• pp.89-99
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• 2000

This report was done to observe the effect of Hominis placenta herbal acupuncture on Bell's palsy. The study group comprised 16 patients who arrived at Woo-suk university oriental hospital from January, 1999 till January, 2000 for Bell's palsy. All patients were divided into two group. One was herbal acupunture group, and the other was control group. Acupunture group was done herbal acupuncture therapy on the facial acupuncture points. Followings are achievement and a term of each group. In herbal acupuncture group, 100% motor recovery was 7 case, 75% was 1 case, and 25% motor recovery term was $7.38{\pm}5.21$ days, 50% was $11.00{\pm}6.16$ days, 75% was $15.13{\pm}9.55$ days, 100% was $23.14{\pm}7.97$ days. In control group, 100% motor recovery was 4 case, 75% was 2 case, 25% below was 2 case and 25% motor recovery term was $11.17{\pm}4.96$days, 50% was $18.17{\pm}6.82$ days, 75% was $29.50{\pm}6.95$ days, 100% was $44.00{\pm}11.49$ days. The above results indicate that Hominis placenta herbal acupuncture is a useful effect on Bell's palsy. thus, continuous herbal acupunture study will be needed for more clinical application on Bell' palsy.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.419-427
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• 2018

In case high strength steels are applied for press-formed automotive parts, it is very difficult to secure forming accuracy due to large springback compared to moderate strength steels. In this study, a repetitive step-wise forming analyses based on secant method was proposed as the die design method for mandrel(bending tool) for the 2-axis bending equipments. A bending die with circular mandrel was designed for the DP780 blow motor case of which diameter and thickness are 70.8mm and 2.0mm respectively. Forming tests were performed to verify the validity of established die design and the results were compared with that of conventional HGI(Hot galvanized iron steel) blow motor case. For additional improvement in forming accuracy, an elliptical mandrel was proposed and its validity was verified using forming analyses based on secant method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.8
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• pp.539-546
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• 1987

In case of operating at Variable speed the induction motor by a frequency transformer, it will cause ripples in motor torque and considerably bad effects on the machines because the output side of the frequency transformer involves a great number of harmonics. This paper Presents the methods of decreasing torque ripples in induction motor and of improving current waveform, by means of forming the waveforms of output current into multi-step waveforms similiar to sinusoid, and also by means of eliminating the harmonic components maximally, in case of operating a 18-phase multi-inverter combining 3-step current source inverter.

• Annals of Clinical Neurophysiology
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• v.14 no.1
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• pp.41-44
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• 2012

Thenar motor neuropathy (TMN) is a compressive mononeuropathy of recurrent motor branch of median nerve. It is infrequent and may have different pathogenesis. It may be a unique entity of disease or considered a variant of carpal tunnel syndrome involving the motor branch only. We report a case of TMN induced by vigorous massage that applied strong digital pressure in the region of the base of palm and thenar muscles.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.203-205
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• 2006

This paper presents a study on the winding method and structure of core of single phase induction motor in order to design the high efficiency motor. In case of single phase induction motor, winding fill factor and the number of turns in each slot are not uniform in general. Moreover, these can be the critical parameters for high efficiency design in case the size of motor should be restricted within certain volume. Therefore, we should analyze the effects of these parameters related to efficiency parameter. The characteristic analysis was performed by using FEM.

• Annals of Clinical Neurophysiology
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• v.7 no.1
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• pp.31-33
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• 2005

Segmental zoster paresis (SZP) is a clinically rare complication of herpes zoster. But it has not been reported that acute cerebral motor cortical infarction coincidentally occurred in SZP. A 86-year-old woman was admitted due to pain, tingling sensation, and weakness of left arm. She had an acute onset of pain and tingling sensation in left arm at first day, shoulder weakness at second day, and multifocal vesicles at fourth day. Deep tendon reflexes of left arm were decreased than right. Electromyography showed an axonal polyneuropathy at superior trunk level of left brachial plexus. Median and ulnar sensory evoked potential tests were normal. Brain MRI showed a high signal in right primary motor cortex on diffusion weighted image. We report a case of acute cerebral motor cortical infarction coincidentally occurred in SZP.