• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.55-58
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• 2003

IPMSM (Interior Permanent Magnet Synchronous Motor) is widely used in many applications such as an electric vehicle, compressor drives of air conditioner and machine tool spindle drives. In order to maximize the efficiency in such applications, this paper is proposed the optimal control method of the armature current. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal control of the armature current. The minimization of loss is possible to realize efficiency optimization control for the proposed IPMSM The proposed control algorithm is applied to IPMSM drive system, the operating characteristics controlled by efficiency optimization control are examined in detail by simulation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.3
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• pp.206-214
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• 1991

Flow field in a hard disk drive has been predicted numerically. Theoretical model was constructed based on a commercially available hard disk drive with 40 Mega byte capacity. Since the gap between disk tip and shroud is not homogeneous in real hard disk drive, three kinds of gap size have been tested as computational model. The discussion has been made on the circumferential velocity, radial velocity, and pressure fields. As a result, the average shear stress on the disk surface was reduced as the gap size decreased. This means that the shroud should be designed compactly to reduce power consumption of the spindle motor.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.119-123
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• 1996

The demands for robotic and automatic system are continually increasing in manufacturing fields. There were so many studies to monitor and predict system, but it were mainly relied upon measuring of cutting force, current of motor spindle and using acoustic sensor, etc. In this study digital image of time series sequence was acquired taking advantage of optical technique. Then, mean square error was obtained from it and was available for useful observation data. The parameter was estimated using PAA(parameter adaptation algorithm) from observation data. AR model was selected for system model, fifth order was decided according to parameter estimation. Uncorrelation test was also carried out to verify convergence of parameter. Through the proceedings, we found there was a system stability.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.12
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• pp.697-703
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• 2002

Interior permanent magnet synchronous motor(IPMSM) is widely used in many applications such as an electric vehicle, compressor drives of air conditioner and machine tool spindle drives. In order to maximize the efficiency in such applications, this paper is proposed the optimal control method of the armature current. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal control of the armature current. The minimization of loss is possible to realize efficiency optimization control for the proposed IPMSM The optimal current can be decided according to the operating speed and the load conditions. The proposed control algorithm is applied to IPMSM drive system, the operating characteristics controlled by efficiency optimization control are examined in detail by simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04a
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• pp.626-630
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• 1995

최근산업의 발달과 함께 제품의 생산성 및 품질 향상을 위하여 공작기계의 고속화 기술에 대한 연구가 머시닝센터를 중심으로 활발히 진행되고 있다. 공작기계의 고속화에 적합한 주축시스템으로는 모터내장형 주축(Built-in Motor Type Spindle)이 많이 응용되고 있으며, 앞으로더욱 수요가 증대될 것이 예상되어 독일, 일본 등의 선진국에서도 활발히 연구 개발이 이루어지고 있다. 본 연구에서는 모터발열을 억제하기 위한 냉각방법으로 오일자켓 냉각방식을 채택하여 모터부에 자켓을 설치, 운전함으로써 모터내장형 주축에 대한 오일자켓냉각방식의 냉각특성을 알아보고, 또한 모터부의 오일자켓 냉각과 함께 몇가지 방법으로 공기냉각을 추가하였을 때의 냉각특성을 고찰하여 보다 효율적인 냉각방법을 제시하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.791-798
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• 2001

As the form factor of the disk drive is decreased, many mechanical issues that are negligible in larger form factors, should be considered for the design of the miniature drives. This paper deals with basic research on vibration characteristics and design considerations of small disks and actuators. The natural frequencies of micro-sized disks with polycabonate and glass substrates are experimentally measured, being compared to FEM results. In order to investigate the effects of rotating speeds, airflow and disk size on power consumption. we measure power imposed to spindle motor when different optical disks are spins in vacuum chamber. Finally, The vibration characteristics of the micro actuator used in a IBM Microdrive are experimentally studied for the application to the basic design of micro optical disks.

• Journal of Power Electronics
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• v.17 no.4
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• pp.963-971
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• 2017

Torque ripple is one of the major sources inducing vibration and noise in brushless DC motors. This is especially true in applications such as the spindle motors used in hard disk drives. However, the relationship between torque ripple and acoustic noise/vibration is quite complicated. This paper presents a way to investigate this relationship with acoustic noise measurement and analysis. Results obtained with three different drive modes are used in the analysis. The results show that the acoustic noise analysis is very helpful in designing a high-performance drive strategy for BLDC motors.

• Physical Therapy Korea
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• v.8 no.4
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• pp.81-89
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• 2001

There are two independent mechanisms to control the segmental reflex gain in humans during gait. They are presynaptic inhibition and homosynaptic depression. Through the mechanism of the presynaptic inhibition, the muscle spindle afferent feedback can be properly gated during eccentric phase of gait. The modulation of the presynaptic inhibition is reflected in the level of H-reflex at a constant EMG level. During the eccentric muscle activation presynaptic inhibition should increase to account for the lower amplitude level of H-reflex at a constant level of EMG. Homosynaptic depression is another mechanism responsible for regulating the effectiveness of the muscle spindle afferent feedback. Both the presynaptic inhibition and the monosynaptic depression are responsible for modulating reflex gain during gait initiation. Reflex modulation is influenced not only as a passive consequence of the alpha motor neuron excitation level, but also through supraspinal mechanisms. Spastic paretic patients show the impaired soleus H-reflex modulation either during the initial stance phase, or during the swing phase. This abnormal modulatory mechanism can partially and artificially be restored by the application of peripheral stimulus to the sole of the foot, provided that the segmental circuitry remains functional.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.253-260
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• 2005

Mitotic centromere-associated kinesin (MCAK), which is a member of the Kin I (internal motor domain) subfamily of kinesin-related proteins, is known to play a role in mitotic segregation of chromosome during M phase of the cell cycle. In the present study, we have produced a rat polyclonal antibody using human MCAK (HsMCAK) expressed in E. coli as the antigen. The antibody specifically recognized the HsMCAK protein (81 kDa), and could detect its nuclear localization in human Jurkat T cells and 293T cells by Western blot analysis. The specific stage of the cell cycle was obtained through blocking by either hydroxyl urea or nocodazole and subsequent releasing from each blocking for 2, 4, and 7 h. While the protein level of HsMCAK reached a maximum level in the S phase with slight decline in the $G_{2}-M$ phase, the electrophoretic mobility shift from $p81^{MCAK}\;to\;p84^{MCAK}$ began to be induced in the late S phase and reached a maximum level in the $G_{2}/M $ phase, and then it disappeared as the cells enter into the $G_{1}$ phase. Immunocytochemical analysis revealed that HsMCAK protein localized to centrosome and nucleus at the interphase, whereas it appeared to localize to the spindle pole, centromere of the condensed mitotic DNA, spindle fiber, or midbody, depending on the specific stage of the M phase. These results demonstrate that a rat polyclonal antibody raised against recombinant HsMCAK expressed in E. coli specifically detects human MCAK, and indicate that the electrophoretic mobility shift from $p81^{MCAK}\;to\;p84^{MCAK}$, which may be associated with its differential intracellular localization during the cell cycle, fluctuates with a maximum level of the shift at the $G_{2}-M$ phase.

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.109-112
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• 2011

Purpose: Neurofibromas may present as multiple or solitary lesions. Although there is no predilection site for solitary lesions, they are rare on the hand. In addition, solitary intramuscular neurofibromas are a very rare pathological type. Here, we report a rare solitary intramuscular neurofibroma in the hand. This paper examines the clinical characteristics of intramuscular neurofibroma arising from the lumbricalis in order to enable a correct diagnosis and treatment. Methods: A 32-year-old male presented with a painless mass on the palm. The physical examination revealed a $3{\times}2$ cm protruding mass that was non-tender to palpation. The vascular and sensory examinations were unremarkable, while the motor examination showed mild difficulty with flexion and extension. Magnetic resonance imaging demonstrated an enhancing solid mass between the thenar eminence and second metacarpophalangeal joint. The diagnosis of an intramuscular neurofibroma was confirmed following surgical excision and histological evaluation. Results: The pathological examination was consistent with a neurofibroma, with delicate fascicles and loose fusiform cells in a fibrous stroma, with oval or spindle-shaped nuclei and scant cytoplasm. The background matrix was pale staining and had focal myxoid stroma. There was no significant nuclear pleomorphism and no mitoses. Immunohistochemistry with S-100 was slightly positive. At the 6-month follow-up, motor and sensory function were intact and the range of motion was full. Conclusion: A neurofibroma is a rare tumor of the hand, especially the intramuscular type. Hand surgeons should consider the diagnosis of this tumor based on the examination and imaging.