• Journal of Industrial Technology
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• v.29 no.A
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• pp.3-8
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• 2009

Vibration characteristics of a 6kW stand alone W/T(wind turbine) system are experimentally and theoretically investigated. Vibration resonance of the tower-cable system is monitored and the data are analysed and compared with the analytical results. To predict the resonance speed of the cable supported W/T, Rayleigh-Ritz method is applied to the tower-guy cable coupled system. Parametric study on the relation of the cable tension, cable elasticity and resonance frequency is carried out. Results of the study are utilized to design the stable structure of small size wind turbines which consist of a pivoted tower and guy cables.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.385-389
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• 2019

Schwannoma or neurilemmoma is a benign peripheral nerve sheath tumor that arises from Schwann cells. Approximately 25-45% of all schwannomas occur in the head and neck regions, and the intraoral presentation of these is only 1%. We report a rare case of a patient presenting tongue base schwannoma with characteristic imaging features on computed tomography and magnetic resonance imaging.

• Journal of Magnetics
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• v.21 no.2
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• pp.187-191
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• 2016

Retrieving the equivalent electromagnetic parameters (permittivity and permeability) plays an important role in the research and application of metamaterials. Frequency dispersion of magnetic permeability has been theoretically predicted in a metamaterial composed of cut wire pairs (CWP) separated by dielectric substrate on the basis of circuit theory. Magnetic resonance resulting from antiparallel currents between the CWP is observed at the frequency of minimum reflection loss (corresponding to absorption peak) and effective resonator size can be determined. Having calculated the circuit parameters (inductance L, capacitance C) and resonance frequency from CWP dimension, the frequency dispersion of permeability of Lorentz like magnetic response can be predicted. The simulated resonance frequency and permeability spectra can be explained well on the basis of the circuit theory of an RLC resonator.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.799-807
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• 2013

The proper equivalent circuit is newly presented for electro-magnetic resonance based wireless power transfer. Based on the proposed equivalent circuit of open-ended helical antennas, the parameter identification of helical antennas can be well derived for highly efficient wireless power transfer. The well-established equivalent circuit in high frequency ranges is developed for analyzing a resonance enhanced-electromagnetic coupling helical antennas and the unknown parameters for helical antennas are identified by experiments. The effectiveness based on the proposed equivalent circuit is verified through experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.866-869
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• 2004

Power transformers, air-intakes and stacks in the urban combined power plant are main noisy sources. Because of Inhabitant complaint by abnormal noise transferred from the power plant. the noise was investigated at power plant and uptown area. The result of diagnosis made the acoustic resonance phenomenon by 580Hz's combustion dynamic pressure with the standing wave mode of sound fields in exhaust passageway of gas turbine into main noise source of public complain. The abnormal noise is caused by the resonance exhaust noise transferred through stacks of power plant.

• Interaction and multiscale mechanics
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• v.3 no.2
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• pp.111-121
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• 2010

Dynamic analysis of nano/micro bio-sensors based on a multiscale atomistic/continuum theory is introduced. We use a generalized atomistic finite element method (GAFEM) to analyze a bio-sensor which has $3{\times}N_a{\times}N_p$ degrees of freedom, where $N_p$ is the number of representative unit cells and $N_a$ is the number of atoms per unit cell. The stiffness matrix is derived from interatomic potential between pairs of atoms. This work contains two studies: (1) the resonance analysis of nano bio-sensors with different amount of target analyte and (2) the dependence of resonance frequency on finite element mesh. We also examine the Courant-Friedrichs-Lewy (CFL) condition based on the highest resonance frequency. The CFL condition is the criterion for the time step used in the dynamic analysis by GAFEM. Our studies can be utilized to predict the performance of micro/nano bio-sensors from atomistic perspective.

• Journal of Veterinary Clinics
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• v.38 no.2
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• pp.89-93
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• 2021

2-Month-old, three related Perro de Presa Canario dogs were evaluated for similar neurological symptoms like circling, head pressing, depressed mental status, hypermetria, and vocalization. On magnetic resonance imaging (MRI) of the brain, there were large, bilaterally symmetrical lesions with involvement of thalamus, and brainstem that were T2- and FLAIR-hyperintense and T1-iso/hypointense. There was no inclusion of cerebellum. Single-voxel spectroscopy acquisition was located in the thalamus where abnormalities were found in MR images. The results of magnetic resonance spectroscopy (MRS) showed markedly decreased N-acetylaspartic acid value. Euthanasia was performed and lesions consistent with the canine spongy degeneration. Alteration in metabolites in the brain can be determined by MRS, which helps in diagnosing degeneration/leukodystrophy of the central nervous system in dogs.

• Investigative Magnetic Resonance Imaging
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• v.25 no.2
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• pp.135-140
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• 2021

Breast angiosarcoma is a very rare manifestation. Herein, we report a case of breast angiosarcoma in a 21-year-old woman admitted to our hospital with a one-year history of a palpable mass with fullness and swelling of the right breast. The various imaging findings, including mammography, ultrasound (US), and magnetic resonance imaging (MRI), of this rare disease are described. The imaging findings of US and combined MRI of breast angiosarcoma were specific in this case. The imaging characteristics could be helpful in detecting and diagnosing breast angiosarcoma in young women with a palpable mass with fullness and swelling of the breast.

• Journal of the Korean Magnetic Resonance Society
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• v.27 no.4
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• pp.28-34
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• 2023

We study the linear-nonlinear quantum transport theory of Wannier-Landau transition system in the confinement of electrons by a square well confinement potential. We use the projected Liouville equation method with the ensemble density projection technique. We select the dynamic value under a linearly oscillatory external field. We derive the dynamic value formula and the memory factor functions in three electron phonon coupling systems and electron impurity coupling systems of two transition types, the intra-band transitions and inter-band transitions. We obtain results that can be applied directly to numerical analyses. For simple example of application, we analyze the absorption power and line-widths of ZnO, through the numerical calculation of the theoretical result in the Landau system.

• Journal of the Korean Magnetic Resonance Society
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• v.27 no.2
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• pp.16-16
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• 2023