• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.347-350
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• 2006

The high efficiency full-bridge LLC resonant converter using a contact-less transformer is proposed for the photovoltaic power generation system. For the series resonance with a series capacitor, the LLC resonant converter utilizes the leakage inductance and magnetizing inductance of a contact-less transformer. Unlike the conventional series resonant converter operated to the continuous resonant current at above resonance frequency, the proposed converter operates to the discontinuous resonant current at the narrow frequency control range below resonance frequency. Due to the discontinuous mode resonant current, the proposed converter can be achieved the zero voltage switching (ZVS) in the primary switches and the zero current switching (ZCS) in the secondary rectification diodes without any auxiliary circuit. In this paper, the experimental results of the proposed full-bridge LLC resonant converter using a contact-less transfonner are verified on the simulation based on the theoretical analysis and the 150W experimental prototype.

• Journal of the Korean Magnetic Resonance Society
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• v.14 no.1
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• pp.45-54
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• 2010

HP1423 (Y1423_HELPY) is a conserved hypothetical protein from H. pylori strain 26695. However, Sequence Blast result indicates that HP1423 belongs to S4 (PF01479) superfamily. According to Pfam database, the S4 domain is a small domain consisting of 60-65 amino acid residues, that probably mediates binding to RNA. In this study, we report the sequence-specific backbone resonance assignment of HP1423, which has 84 amino acid residues. We could assign unambiguously about 88% of all $^{1}H_{N}$, $^{15}N$, $^{13}C_{\alpha}$, $^{13}C_{\beta}$ and $^{13}C=O$ resonances. We could not detect the resonances from residues 15-20, and disappearance of these peaks seems to be related with the intermediate-conformational exchange. These assigned NMR peaks of HP1423 can be used for studying the role of protein dynamics in millisecond timescale, and Protein-RNA binding.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.3
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• pp.294-300
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• 2004

The present experimental study was designed to address two issues. The first was to investigate whether oxidation voltage of titanium implants influenced bone tissue responses after an in vivo implantation. The second aim was to investigate secondary stability change after 1 to 3months period. Screw-shaped implants with a wide range of oxide properties were prepared by electrochemical oxidation methods, where the oxide thickness varied in the range of $3-15{\mu}m$. The micro structure revealed pore sizes of $1-3{\mu}m$, the crystal structures of the titanium oxide were amorphous, anatase and a mixture of anatase and rutile type. Bone tissue responses were evaluated by resonance frequency measurements that were undertaken 1 to 3months after insertion in the rabbit tibia. It was concluded that no statistical difference of RFA values was found between the groups, RFA gains after Imonth and 3months were calculated.

• Journal of the Korean Chemical Society
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• v.15 no.4
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• pp.177-181
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• 1971

Free radicals of lysozyme produced by $Ti-H_2O_2$ system were studied in aqueous solution at room temperature using ESR with a continuous flow-mixing. The spectra, each consisting of a doublet with 5.5 G splitting and a broad resonance covering 80 G splitting are closely similar in shape to that for solid irradiated in vacuum at $77^{\circ}K$ and observed at room temperature immediately on warming. The result is assumed to indicate that the secondary protein radical components formed within 0.01 second, dead time of the mixing chamber, and initiated by hydrogen atom abstraction at ${\alpha}$-carbon atom of peptide chain in liquid solution at room temperature are identical to those resulting from the initial formation of a mixture of positive holes and negative ions by ionization processes as well as radical fragments by the rupture of chemical bonds in the solid during similar time at the same temperature. A broad resonance is observed with considerable amplitude on the high field side of the doublet, which is quite dissimilar to the spectra of irradiated solid lysozyme. This resonance was tentatively attributed to the polypeptide free radical in which unpaired electrons are localized on side chain.

• Molecules and Cells
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• v.20 no.3
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• pp.442-445
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• 2005

HP0894 (SwissProt/TrEMBL ID O25554) is an 88-residue conserved hypothetical protein from Helicobacter pylori strain 26695 with a calculated pI of 8.5 and a molecular weight of 10.38 kDa. Proteins with sequence similarity to HP0894 exist in Vibrio choierae, Enterococcus faecalis, Campylobacter jejuni, Streptococcus pneumoniae, Haemophilus influenzae, Escherichia coli O157, etc. Here we report the sequence-specific backbone resonance assignments of HP0894. About 97.5% (418/429) of the HN, N, CO, $C{\alpha}$, $C{\beta}$ resonances of the 88 residues of HP0894 were assigned. On the basis of these assignments, three helical regions and four strand regions were identified using the CSI program. This study is a prerequisite for calculating the solution structure of HP0894, and studying its interaction with its substrates, if any, and/or with other proteins.

• Structural Engineering and Mechanics
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• v.35 no.4
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• pp.387-407
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• 2010

In this paper, using perturbation and Galerkin method, the response of a resonant viscoelastic microbeam to an electric actuation is obtained. The microbeam is under axial load and electrical load. It is assumed that midplane is stretched, when the beam is deflected. The equation of motion is derived using the Newton's second law. The viscoelastic model is taken to be the Kelvin-Voigt model. In the first section, the static deflection is obtained using the Galerkin method. Exact linear symmetric mode shape of a straight beam and its deflection function under constant transverse load are used as admissible functions. So, an analytical expression that describes the static deflection at all points is obtained. Comparing the result with previous research show that using deflection function as admissible function decreases the computation errors and previous calculations volume. In the second section, the response of a microbeam resonator system under primary and secondary resonance excitation has been obtained by analytical multiple scale perturbation method combined with the Galerkin method. It is shown, that a small amount of viscoelastic damping has an important effect and causes to decrease the maximum amplitude of response, and to shift the resonance frequency. Also, it shown, that an increase of the DC voltage, ratio of the air gap to the microbeam thickness, tensile axial load, would increase the effect of viscoelastic damping, and an increase of the compressive axial load would decrease the effect of viscoelastic damping.

• Journal of Breast Cancer
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• v.21 no.4
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• pp.453-462
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• 2018

Purpose: This study aimed to compare the diagnostic performance of contrast-enhanced digital mammography (CEDM) and contrast-enhanced magnetic resonance imaging (CEMRI) in preoperative evaluations, and to evaluate the effect of each modality on the surgical management of women with breast cancer. Methods: This single-center, prospective study was approved by the Institutional Review Board, and informed consent was obtained from all patients. From November 2016 to October 2017, 84 patients who were diagnosed with invasive carcinoma (69/84) and ductal carcinoma in situ (15/84), and underwent both CEDM and CEMRI, were enrolled. Imaging findings and surgical management were correlated with pathological results and compared. The diagnostic performance of both modalities in the detection of index and secondary cancers (multifocality and multicentricity), and occult cancer in the contralateral breast, was compared. The authors also evaluated whether CEDM or CEMRI resulted in changes in the surgical management of the affected breast due to imaging-detected findings. Results: Eighty-four women were included in the analysis. Compared with CEMRI, CEDM demonstrated a similar sensitivity (92.9% [78/84] vs. 95.2% [80/84]) in detecting index cancer (p=0.563). For the detection of secondary cancers in the ipsilateral breast and occult cancer in the contralateral breast, no significant differences were found between CEDM and CEMRI (p=0.999 and p=0.999, respectively). Regarding changes in surgical management, CEDM resulted in similar changes compared with CEMRI (30.9% [26/84] vs. 29.7% [25/84], p=0.610). Regarding changes in surgical management due to false-positive findings, no significant differences were found between CEDM and CEMRI (34.6% [9/26] vs. 44.0% [11/25], p=0.782). Conclusion: CEDM demonstrated a diagnostic performance comparable with CEMRI in depicting index cancers, secondary cancers, and occult cancer in the contralateral breast. CEDM demonstrated similar changes in surgical management compared with CEMRI.

• Journal of Power Electronics
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• v.17 no.1
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• pp.11-19
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• 2017

This paper proposes a dc/dc converter for electric vehicle onboard chargers using a secondary resonant tank. To attain soft switching characteristics, such as zero voltage switching, magnetizing inductance has been used at the primary side of the transformer. The leakage inductance of the transformer is used as a resonant inductor on the secondary side to avoid the use of a separate inductor as resonance. The proposed converter is applicable for a wide load range. A 6.6KW prototype has been implemented for a wide range of load variations (250V, 330V, 360V, and 413V). A maximum efficiency of 97.4% is achieved at 413V.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.4
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• pp.636-642
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• 2017

Recently, new power devices, SiC and GaN FETs, are commercialized. They are expected to change power electronics environments. They will raise operating frequencies of power electronic equipments. Accordingly, design method will be changed greatly. In this paper, an 1 MHz resonant converter with fully compensated coreless isolation transformer is proposed, where the primary voltage is proportional to the secondary current and the primary current to the secondary voltage. 30 W prototype is constructed and tested, and its usefulness is verified.

• Annals of Clinical Neurophysiology
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• v.20 no.1
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• pp.36-40
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• 2018

Lennox-Gastaut syndrome (LGS) is an electro-clinical syndrome composed of the triad of mental retardation, multiple seizure types, and the characteristic generalized slow spike-wave complexes in the electroencephalogram. In this article, we report on two patients with LGS whose brain magnetic resonance imaging showed dysgenesis of corpus callosum (CC). We discuss the role of CC in the genesis of secondary bilateral synchrony.