• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2067-2070
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• 2005

This paper presents an approach to evaluate the appropriate parameters for Piezoelectric ceramic utilization by adopting Impedance Method. Butterworth Van Dyke model (BVD) is considered to use as an equivalent circuit of Piezoelectric ceramic in case of no load. The experimental results from this model will be compared with the results from a circular Piezoelectric ceramic with 4.8 cm. diameter and 3 mm. thickness. The Thickness Mode vibration measured by Impedance Analyzer model 4192A can be analyzed from 1Hz to 13MHz for calculating and analyzing parameters at resonance frequency and anti-resonance frequency. These parameters are evaluated to design the efficient circuit for Piezoelectric ceramic utilization to obtain the optimal efficiency.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.204-209
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• 2001

The finite element model for automotive muffler analysis is improved by modifying the boundary condition of outlet and the mesh of finite element model. The model minimizes the difference between transmission loss from analysis and that from experiment. Four different boundary conditions and the four types of finite element model are tested to find out the best one of those. From the case study it is verified that the bevel of transmission loss can be changed by the variation of radiation impedance value. Also the resonance or anti-resonance frequencies of transmission loss can be shifted by the variation of finite element mesh. An improved finite element model of muffler is proposed in consideration with the accuracy and the computing time of analysis.

• Journal of Korean Neurosurgical Society
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• v.44 no.1
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• pp.36-39
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• 2008

Although tuberculosis of the central nervous system is well known, the incidence of intramedullary tuberculomas is low and a combination of intramedullary with intracranial tuberculomas is extremely rare. We report a case of disseminated tuberculoma involving brain and spine with miliary pulmonary tuberculosis in a 66-year-old woman initially presenting with fever, general weakness, back pain and motor weakness of both lower extremities. Despite medical therapy, she developed progressive motor weakness of both lower extremities with muscle strength 1/5 in both lower extremities. Urgent surgical intervention was followed and her muscle power and motor functions were improved gradually. The anti-tuberculous drugs were continued and the follow-up magnetic resonance imaging (MRI) of brain and spine showed that the lesions had become smaller or disappeared.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.1
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• pp.23-28
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• 2015

Four spiroketal sestertepenoids (1 ~ 4) were isolated from the marine sponge Haliclona species. Their planar structures were completely determined from a combination of extensive 1D and 2D NMR experiments, and also the relative stereochemistry on the chiral centers were established by the ROESY experiment. Compounds 1 ~ 3 were determined as the same planar structures with different stereochemistry on the chiral centers C-11 and C-13. Of these, 1 was identified as a new stereoisomer. Four compounds showed the inhibition effect of nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells (0.7~2.0 g/ml).

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.360-367
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• 2003

This paper presents passive vibration control method to suppress train-induced vibration on a long-span steel arch bridge. According to the train load frequency analysis, undesirable resonance of a bridge will occur when the impact frequency of the train axles are close to the modal frequencies of the bridge. Because the first mode shape of the long-span steel arch bridge may take anti-symmetric shape along the bridge direction, however, the optimal control configuration for resonance suppression should be considered carefully In this study, bridge-vehicle element is used to estimate the bridge-train interaction precisely. From the numerical simulation of a loom steel arch bridge under TGV-K train loading, dynamic magnification influences are evaluated according to vehicle moving speed and efficient control system with passive dampers are presented in order to diminish the vertical displacement and vertical acceleration.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.550-558
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• 2019

The roll motion of a general vessel, which is more influenced by resonance as compared to other motions, adversely affects the passenger and hull. Therefore, reducing the roll motion through an anti-rolling system is critical, and most ships use various devices such as anti-rolling tanks, bilge keels, and fin stabilizers to accomplish this. In this study, a simplified model is developed for the application of an anti-rolling device for unmanned semi-submersible vessels. The applied anti-rolling device is installed on the stern and stem of a ship using a pair of servo motors with added weight, and the motor is controlled through the Arduino. The moment of the motor is designed and implemented based on a mathematical model such that it is calculated through the restoring force according to the heel angle of the ship. The performance of the proposed system was verified by utilizing the roll damping coefficient calculated by the free-roll decay test and logarithmic decrement method and was validated by a towing tank test. The system is expected to be used for unmanned vessels to perform sustainable missions.

• Journal of Korean Neurosurgical Society
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• v.51 no.5
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• pp.316-319
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• 2012

A 24-year-old man presented with mental change, fever, abdominal pain, tenderness and palpable mass on the lower abdomen. He was a non-Korean engineer and did not accompany a legal guardian, so medical history taking was difficult due to his mental status. Brain magnetic resonance imaging showed multiple rim-enhanced lesions of the brain, and abdominal computed tomography showed huge paraspinal abscess. Chest X-ray and computed tomography showed poorly defined nodular opacities. We initially thought that this patient was infected with toxoplasmosis with typical cerebral image finding and immunoglobulin laboratory finding of cerebrospinal fluid and serum study. The abdominal abscess was confirmed as tuberculosis through the pathologic finding of caseous necrosis. We used anti-tuberculosis medication and anti-toxoplasmosis medication for almost 4 months, and then his clinical state and radiological findings were considerably improved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2230-2235
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• 2011

The purpose of this paper is to provide the unbalanced magnetic force and vibration mode comparison between two large interior permanent magnet machines(IPM) with different pole-slot combination considering stator and rotor eccentricity. Due to the punching tolerance, the mixed eccentricity of air-gap is inevitable. It will generate the asymmetric magnetic flux density in air-gap, which makes the unbalanced magnetic pull and vibration. The study is focused on the unbalanced magnetic force and their harmonic components according to eccentricity conditions such as static, dynamic and mixed. When the high vibration is produced especially resonance, the obtained results provide clues what eccentricity condition occurs in the machine.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.474-477
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• 2005

Surface Plasmon Resonance(SPR) sensor system can be applicable for detecting of many biospecific interactions. In this study, the feasibility of the experimental $SPREETA^{TM}$ evaluation kit to analyze human IgG, Pseudomonas aeruginosa, was investigated. The sensor prepared for detecting of anti-human IgG has response on $0.1{\mu}{\ell}$ of the anti-human IgG solution. SPREETA was able to detect P. aeruginosa solution in the range above $10^8\;CFU/mL$ with the chitosan/ alginate multilayers.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.137-139
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• 2003

Transducer for ultrasonic linear motor with the symmetric and anti-symmetric modes was studied. The ultrasonic linear motor consists of two Langevin type piezoelectric vibrators that cross at right angles with each other in tip. In order to excite symmetric and anti-symmetric modes, the transducer must have a phase shift of 90 degree in space and time. Therefore, the tip of transducer moves on an elliptical motion. In this paper, the finite element analysis was used to optimize dimension and displacement of the transducer The ultrasonic motor was fabricated using the simulated result and the driving characteristics were measured. No-load velocity was 0.28[m/s] and the maximum efficiency was 30[%] in resonance frequency.