Y. S. Lee

Soonchunhyang University, Onyang, Chungcheongnam-do, South Korea

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Publications (620)1539.21 Total impact

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    ABSTRACT: A Korean fusion energy development promotion law (FEDPL) was enacted in 2007. As a following step, a conceptual design study for a steady-state Korean fusion demonstration reactor (K-DEMO) was initiated in 2012. After the thorough 0D system analysis, the parameters of the main machine characterized by the major and minor radii of 6.8 and 2.1 m, respectively, were chosen for further study. The analyses of heating and current drives were performed for the development of the plasma operation scenarios. Preliminary results on lower hybrid and neutral beam current drive are included herein. A high performance Nb3Sn-based superconducting conductor is adopted, providing a peak magnetic field approaching 16 T with the magnetic field at the plasma centre above 7 T. Pressurized water is the prominent choice for the main coolant of K-DEMO when the balance of plant development details is considered. The blanket system adopts a ceramic pebble type breeder. Considering plasma performance, a double-null divertor is the reference configuration choice of K-DEMO. For a high availability operation, K-DEMO incorporates a design with vertical maintenance. A design concept for K-DEMO is presented together with the preliminary design parameters.
    Nuclear Fusion 05/2015; 55(5):053027. DOI:10.1088/0029-5515/55/5/053027 · 3.24 Impact Factor
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    ABSTRACT: We have investigated the electronic structure and carrier dynamics of the topological insulator Bi 2−x Sb x Te 3−y Se y , for x = 0.5, y = 1.3 and x = 1, y = 2, using infrared spectroscopy. Our results show that both of these BSTS alloys are highly insulating in the bulk, with analysis of the infrared data indicating an upper limit to the carrier density of 4.4 × 10 17 cm −3. Furthermore, analysis of the interband transitions of Bi 1.5 Sb 0.5 Te 1.7 Se 1.3 revealed distinct band-structure critical points, which suggest high crystallographic order of our crystals. Motivated by the low carrier density and crystallographic order identified in these compounds, we searched for the Landau level transitions associated with the surface states through magneto-optical measurements in the far infrared range. We failed to observe any indications of the Landau level resonances at fields up to 8 T in sharp contrast with our earlier finding for a related Bi 1−x Sb x alloy. We discuss factors that may be responsible for suppressed magneto-optics response of these single crystals.
    Physical Review B 04/2015; 91(16):165202. DOI:10.1103/PhysRevB.91.165202 · 3.66 Impact Factor
  • Journal of Hepatology 04/2015; 62:S452-S453. DOI:10.1016/S0168-8278(15)30588-2 · 10.40 Impact Factor
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    ABSTRACT: We investigated the strain effect on temperature-dependent photoluminescence property in the clamped (with template) and free-standing (without template) PbTiO3 (PTO) nanotubes. The wall-thickness of nanotubes was varied from 25 to 80 nm with the outer diameter fixed to 420 nm. While all nanotubes show sizable green/yellow emission, the temperature dependent shift of the emission energy is significantly suppressed in the clamped PTO nanotubes, which is attributed to the lattice strain driven by the template clamping. This clamping effect is more significant for thinner nanotubes. Even in the free-standing PTO nanotubes the temperature-dependence of emission is affected by the wall-thickness. Our finding is the clear manifestation of the template and geometrical shape effect on the optical property of the nanotubes.
    Current Applied Physics 02/2015; 15(2). DOI:10.1016/j.cap.2014.11.017 · 2.03 Impact Factor
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    ABSTRACT: Reports have been issued recently on single incision laparoscopic hernioplasty, but no large-scale study has been conducted as yet. This study aimed to assess the safety and feasibility of the single incision laparoscopic totally extraperitoneal hernioplasty (SIL-TEP) on a large number of cases. 512 SIL-TEPs in 471 patients were performed from June 2010 to January 2014 at Incheon St. Mary's Hospital, The Catholic University of Korea. SIL-TEP was performed using a glove single port device and standard laparoscopic instruments. Short-term outcomes were reviewed. Of the 512 hernias, 329 (64.3 %) were indirect, 144 (28.1 %) were direct, 9 (1.8 %) were femoral, and 30 (5.9 %) were combined. There were 3 (0.6 %) conversions to single or three-port laparoscopic transabdominal preperitoneal hernioplasty. Mean operative time was 41.6 min for unilateral hernias and 65.3 min for bilateral hernias. Postoperative complications occurred in 45 cases (9.6 %); 21 were wound seromas, 5 were hematomas, and 18 were urinary retentions. All were successfully treated conservatively. Mean hospital stay was 1.8 days. The SIL-TEP is safe and technically feasible. Additional studies on long-term recurrence rates are needed to confirm the safety of SIL-TEP.
    Hernia 12/2014; 19(3). DOI:10.1007/s10029-014-1337-2 · 2.09 Impact Factor
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    ABSTRACT: AimsIn spite of the reported efficacy and safety of antimuscarinics in men with OAB (overactive bladder) and BPO (benign prostatic obstruction), many patients do not persist with the treatment. We aimed to evaluate persistence and the reasons for the discontinuation of solifenacin add-on therapy in men with residual symptoms of OAB after tamsulosin monotherapy for BPO in a real clinical environment.Methods Men aged ≥ 45 years with IPSS ≥ 12 and symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 2/24 h) were prescribed tamsulosin 0.2 mg. After 4 weeks, men who had residual symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 1/24 h) and reported that they were ‘dissatisfied’ or ‘a little satisfied’ with the therapy were enrolled and prescribed solifenacin 5 mg in combination with tamsulosin. After 52 weeks, persistence and the reasons for the discontinuation of solifenacin were evaluated. Factors related to persistence were analysed.ResultsOf the 305 men who had been treated with tamsulosin, 176 were prescribed solifenacin. After 52 weeks, 44 (25%) remained on solifenacin therapy. Of the 132 who discontinued solifenacin, 85 were evaluated on the reason for discontinuation. The three most common reasons for discontinuation were adverse events (AEs) (35%), lack of efficacy (33%), and improvement in symptoms (16%). The aggravation of voiding symptoms was the most common AE leading to discontinuation. Retention was observed in 11 men. None of the demographical or clinical characteristics were significantly related to persistence.Conclusions Only 25% men with OAB and BPO remained on antimuscarinic add-on therapy after 1 year, mostly because of AEs and lack of efficacy. Realistic data should be added to what is already known about antimuscarinic treatment in men by including patients who were excluded or who dropped out of well-designed clinical trials.
    International Journal of Clinical Practice 09/2014; DOI:10.1111/ijcp.12483 · 2.54 Impact Factor
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    ABSTRACT: We investigate near-field infrared spectroscopy and superfluid polariton imaging experiments on conventional and unconventional superconductors. Our modeling shows that near-field spectroscopy can measure the magnitude of the superconducting energy gap in Bardeen-Cooper-Schrieffer-like superconductors with nanoscale spatial resolution. We demonstrate how the same technique can measure the c-axis plasma frequency, and thus the c-axis superfluid density, of layered unconventional superconductors with a similar spatial resolution. Our modeling also shows that near-field techniques can image superfluid surface mode interference patterns near physical and electronic boundaries. We describe how these images can be used to extract the collective mode dispersion of anisotropic superconductors with sub-diffractional spatial resolution.
    Physical Review B 07/2014; 90(1). DOI:10.1103/PhysRevB.90.014502 · 3.66 Impact Factor
  • K.S. Lee, Y.S. Lee, Y.N. Kwon
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    ABSTRACT: We investigated the influence of annealing and secondary warm rolling on the microstructural evolution and mechanical properties of a roll-bonded three-ply Al/Mg/Al sheet. After annealing at 300 °C, the formation of an intermetallic compound (IMC) layer consisting of Mg17Al12 and Mg2Al3 was identified at the interface. Although the thickness of the IMC layer increased with increasing annealing or preheating time, secondary warm rolling after preheating at 300 °C for 10 min significantly reduced the thickness of the IMC layer below 1.5 μm. Also an equiaxed and homogeneous grain morphology of the constituent magnesium alloy was successfully introduced. This resulted in strongly enhanced elongation up to magnesium fracture by 14.5%.
    Materials Science and Engineering A 06/2014; 606:205–213. DOI:10.1016/j.msea.2014.03.082 · 2.41 Impact Factor
  • M. H. Cho, Y. S. Lee
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    ABSTRACT: We investigated the properties of the red emission from Mn-ion-doped SrZrO3 (SZMO) which may be a candidate of a red phosphor for a white light-emitting diode. We assigned optical transitions observed in photoluminescence and photoluminescence excitation spectra according to the Tanabe-Sugano diagram for the d 3 configuration in a perovskite. We estimated the crystal field splitting energy 10Dq and the Racah parameter B to be 19,230 cm−1 and 701 cm−1 for the Mn ion in SZMO, respectively. We found a strong red emission near 650 nm with several sharp peaks related to vibronic modes. The red emission was found to be drastically enhanced at very low temperature and very small doping.
    Journal- Korean Physical Society 06/2014; 64(12):1866-1871. DOI:10.3938/jkps.64.1866 · 0.43 Impact Factor
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    ABSTRACT: We investigate infrared manifestations of the pseudogap in the prototypical cuprate and pnictide superconductors: YBa2Cu3Oy and BaFe2As2 (Ba122) systems. We find remarkable similarities between the spectroscopic features attributable to the pseudogap in these two classes of superconductors. The hallmarks of the pseudogap state in both systems include a weak absorption feature at about 500 cm-1 followed by a featureless continuum between 500 and 1500 cm-1 in the conductivity data and a significant suppression in the scattering rate below 700 - 900 cm-1. The latter result allows us to identify the energy scale associated with the pseudogap $\Delta_{PG}$. We find that in the Ba122-based materials the superconductivity-induced changes of the infrared spectra occur in the frequency region below 100 - 200 cm-1, which is much lower than the energy scale of the pseudogap. We performed theoretical analysis of the scattering rate data of the two compounds using the same model which accounts for the effects of the pseudogap and electron-boson coupling. We find that the scattering rate suppression in Ba122-based compounds below $\Delta_{PG}$ is solely due to the pseudogap formation whereas the impact of the electron-boson coupling effects is limited to lower frequencies. The magnetic resonance modes used as inputs in our modeling are found to evolve with the development of the pseudogap, suggesting an intimate correlation between the pseudogap and magnetism.
    Physical Review B 04/2014; 90(1). DOI:10.1103/PhysRevB.90.014503 · 3.66 Impact Factor
  • Journal of Hepatology 04/2014; 60(1):S431. DOI:10.1016/S0168-8278(14)61224-1 · 10.40 Impact Factor
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    ABSTRACT: We investigate infrared manifestations of the pseudogap in the prototypical cuprate and pnictide superconductors: YBa2Cu3Oy and BaFe2As2 (Ba122) systems. We find remarkable similarities between the spectroscopic features attributable to the pseudogap in these two classes of superconductors. The hallmarks of the pseudogap state in both systems include a weak absorption feature at about 500 cm-1 followed by a featureless continuum between 500 and 1500 cm-1 in the conductivity data and a significant suppression in the scattering rate below 700 - 900 cm-1. The latter result allows us to identify the energy scale associated with the pseudogap $\Delta_{PG}$. We find that in the Ba122-based materials the superconductivity-induced changes of the infrared spectra occur in the frequency region below 100 - 200 cm-1, which is much lower than the energy scale of the pseudogap. We performed theoretical analysis of the scattering rate data of the two compounds using the same model which accounts for the effects of the pseudogap and electron-boson coupling. We find that the scattering rate suppression in Ba122-based compounds below $\Delta_{PG}$ is solely due to the pseudogap formation whereas the impact of the electron-boson coupling effects is limited to lower frequencies. The magnetic resonance modes used as inputs in our modeling are found to evolve with the development of the pseudogap, suggesting an intimate correlation between the pseudogap and magnetism.
  • 02/2014; 29(1):15-20. DOI:10.14346/JKOSOS.2014.29.1.015
  • Y S Lee, S Hur, T-Y Kim
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    ABSTRACT: Mast cells play important roles in allergic inflammatory responses because they produce leukotrienes (LTs), prostaglandins (PGs), and a variety of inflammatory cytokines. Thus, pharmacological interventions for allergies have focused on inhibiting mast cell activation. Homoisoflavanone (HIF), isolated from Cremastra appendiculata Makino, has anti-angiogenic activities; however, its effects on allergic reactions have not been determined. The aim of this study was to assess the inhibitory effects of HIF on mast cell activation, which is critical for anti-allergic reaction and the underlying mechanisms. Enzyme-linked immunosorbent assays, quantitative real-time PCR, western blot analyses, and degranulation assay were performed to measure pro-inflammatory and allergic mediators in PMA/A23187- or IgE/antigen-stimulated mouse bone marrow-derived mast cells (BMMCs), HMC-1, RBL-1, or human PBMC-derived mast cells treated with or without HIF. The anti-allergic effects of HIF were determined in mouse models using dinitrophenol-immunoglobulin E-induced passive cutaneous anaphylaxis (PCA) and compound 48/80-induced ear swelling. Homoisoflavanone down-regulated PGD2 , LTB4 , and LTC4 production and inhibited the production of pro-inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-α in PMA/A23187- or IgE/antigen-stimulated mast cells. The molecular mechanisms by which HIF caused these inhibitory effects were determined to be the inactivation of spleen tyrosine kinase (Syk) signaling and the concurrent suppression of cPLA2 . HIF inhibited IgE-mediated PCA and compound 48/80-induced ear swelling in mouse. Homoisoflavanone inhibited mast cell activation through the suppression of Syk pathway together with the inhibition of cPLA2 . Thus, it might be a good candidate molecule for allergic diseases.
    Allergy 01/2014; DOI:10.1111/all.12356 · 6.00 Impact Factor
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    ABSTRACT: Since 2001, a series of five irradiation test campaigns for atomized U-Mo dispersion fuel rods, KOMO-1, -2, -3, -4, and -5, has been conducted at HANARO (Korea) in order to develop high performance low enriched uranium dispersion fuel for research reactors. The KOMO irradiation tests provided valuable information on the irradiation behavior of U-Mo fuel that results from the distinct fuel design and irradiation conditions of the rod fuel for HANARO. Full size U-Mo dispersion fuel rods of 4-5 were irradiated at a maximum linear power of approximately 105 kW/m up to 85% of the initial U-235 depletion burnup without breakaway swelling or fuel cladding failure. Electron probe microanalyses of the irradiated samples showed localized distribution of the silicon that was added in the matrix during fuel fabrication and confirmed its beneficial effect on interaction layer growth during irradiation. The modifications of U-Mo fuel particles by the addition of a ternary alloying element (Ti or Zr), additional protective coatings (silicide or nitride), and the use of larger fuel particles resulted in significantly reduced interaction layers between fuel particles and Al.
    Nuclear Engineering and Technology 12/2013; 45(7). DOI:10.5516/NET.07.2013.715 · 0.76 Impact Factor
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    ABSTRACT: We investigated the electronic structure of newly-synthesized Cu-ion-doped SrZrO3 by using photoluminescence and optical spectroscopic techniques. We found that the Cu-ion doping gave rise to the formation of a mid-gap state as deep acceptor within the fundamental bandgap of SrZrO3, which was responsible for red and green emissions. The two-peak structure of the visible emission in our samples was compared with the emission spectra of transition-metal ion-doped semiconductors such as group II-VI and ZnO. The mid-gap state of the Cu 3d orbitals was also identified in the absorption spectra. We suggest a schematic picture for the electronic states of Cu-ion-doped SrZrO3.
    Journal- Korean Physical Society 12/2013; 63(11). DOI:10.3938/jkps.63.2185 · 0.43 Impact Factor

Publication Stats

8k Citations
1,539.21 Total Impact Points

Institutions

  • 2013
    • Soonchunhyang University
      Onyang, Chungcheongnam-do, South Korea
  • 2008–2013
    • National Fusion Research Institute
      • Fusion Engineering Center
      Daiden, Daejeon, South Korea
    • University of Nottingham
      • Division of Molecular and Cellular Science
      Nottigham, England, United Kingdom
    • Chung-Ang University
      Sŏul, Seoul, South Korea
    • Samsung Medical Center
      Sŏul, Seoul, South Korea
  • 2006–2013
    • Keimyung University
      Sŏul, Seoul, South Korea
    • Soongsil University
      • Department of Physics
      Sŏul, Seoul, South Korea
    • Korea Electrotechnology Research Institute-KERI
      Tsau-liang-hai, Busan, South Korea
    • Genomictree
      Yangju-gun, Gyeonggi Province, South Korea
    • Korea Centers for Disease Control and Prevention
      Daiden, Daejeon, South Korea
    • Hallym University Medical Center
      Sŏul, Seoul, South Korea
    • Dong-A University
      • Department of Biotechnology
      Tsau-liang-hai, Busan, South Korea
  • 2005–2013
    • Kyungpook National University Hospital
      • Department of Obstetrics and Gynecology
      Sŏul, Seoul, South Korea
  • 2004–2013
    • University of California, San Diego
      • Department of Physics
      San Diego, California, United States
  • 2006–2012
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2003–2012
    • Sungkyunkwan University
      • Samsung Medical Center
      Sŏul, Seoul, South Korea
    • Pohang Accelerator Laboratory
      Urusan, Ulsan, South Korea
  • 1998–2012
    • Massachusetts Institute of Technology
      • • Department of Physics
      • • Department of Materials Science and Engineering
      Cambridge, Massachusetts, United States
    • Freie Universität Berlin
      Berlín, Berlin, Germany
  • 2011
    • Korea Institute of Materials Science
      Sŏngnam, Gyeonggi-do, South Korea
  • 2003–2011
    • Korea Institute of Science and Technology
      Sŏul, Seoul, South Korea
  • 1998–2011
    • Catholic University of Korea
      • • Department of Obstetrics and Gynecology
      • • Department of Internal Medicine
      • • College of Medicine
      • • Department of Radiology
      • • Department of Pathology
      Seoul, Seoul, South Korea
    • Hanyang University
      • • Department of Physics
      • • College of Medicine
      Sŏul, Seoul, South Korea
  • 2010
    • The Seoul Institute
      Sŏul, Seoul, South Korea
    • Inje University
      Kŭmhae, South Gyeongsang, South Korea
    • Seoul National University of Science and Technology
      Sŏul, Seoul, South Korea
    • Sungshin Women's University
      Sŏul, Seoul, South Korea
    • Kwangwoon University
      • Department of Chemistry
      Sŏul, Seoul, South Korea
    • Ewha Womans University
      • College of Pharmacy
      Sŏul, Seoul, South Korea
    • The Chinese University of Hong Kong
      • Department of Clinical Oncology
      Hong Kong, Hong Kong
  • 2008–2010
    • Gyeongsang National University
      • Division of Applied Life Science
      Shinshū, South Gyeongsang, South Korea
  • 2006–2010
    • Hallym University
      Sŏul, Seoul, South Korea
  • 2002–2010
    • Chungnam National University
      • • Department of Mechanical Design Engineering
      • • Department of Applied Biology
      Daiden, Daejeon, South Korea
  • 2000–2010
    • Chonbuk National University
      • • Semiconductor Physics Research Center
      • • Department of Chemical Engineering
      • • Department of Environmental Engineering
      Tsiuentcheou, Jeollabuk-do, South Korea
    • University of Seoul
      • Department of Physics
      Sŏul, Seoul, South Korea
    • Silla University
      Tsau-liang-hai, Busan, South Korea
    • National Veterinary Research Quarantine Service
      Sŏul, Seoul, South Korea
    • Yeungnam University
      • College of Pharmacy
      Asan, South Chungcheong, South Korea
    • Kwandong University
      • College of Medicine
      Kang-neung, Gangwon, South Korea
  • 1999–2010
    • Seoul National University
      • • Department of Physics and Astronomy
      • • Research Institute of Pharmaceutical Sciences
      • • Department of Chemistry
      • • School of Mechanical and Aerospace Engineering
      • • Department of Neurology
      • • Institute of Molecular Biology and Genetics
      Seoul, Seoul, South Korea
    • Korea Basic Science Institute KBSI
      Sŏul, Seoul, South Korea
    • Harvard University
      Cambridge, Massachusetts, United States
    • Seoul Medical Center
      Sŏul, Seoul, South Korea
  • 1998–2010
    • Kyungpook National University
      • • Department of Obstetrics and Gynecology
      • • Department of Physics
      • • College of Natural Sciences
      • • Department of Oral Biochemistry
      Daikyū, Daegu, South Korea
  • 2009
    • Pontificia Universidad Católica de Valparaíso
      Ciudad de Valparaíso, Valparaíso, Chile
    • Kangwon National University
      • Department of Animal Biotechnology
      Shunsen, Gangwon-do, South Korea
  • 2007–2009
    • Korea University
      • • Department of Home Economics Education
      • • Department of Anesthesiology and Pain Medicine
      Sŏul, Seoul, South Korea
    • Pohang University of Science and Technology
      • Pohang Accelerator Laboratory
      Geijitsu, Gyeongsangbuk-do, South Korea
    • Inha University
      • Department of Chemistry
      Chemulpo, Incheon, South Korea
  • 2001–2009
    • Asan Medical Center
      Sŏul, Seoul, South Korea
    • Seoul National University Hospital
      Sŏul, Seoul, South Korea
    • National Institute of Health Sciences, Japan
      • Division of Cellular and Molecular Toxicology
      Edo, Tōkyō, Japan
    • Kobe University
      • Department of Chemistry
      Kōbe, Hyōgo, Japan
  • 1998–2009
    • University of Ulsan
      • • Department of Internal Medicine
      • • College of Medicine
      Urusan, Ulsan, South Korea
  • 2007–2008
    • Seoul Metropolitan Children's Hospital
      Sŏul, Seoul, South Korea
  • 2006–2008
    • Korea Institute of Radiological & Medical Sciences
      Sŏul, Seoul, South Korea
  • 2003–2008
    • Hanbat National University
      • Department of Information and Communication Engineering
      Taiden, Daejeon, South Korea
  • 2000–2008
    • Chonnam National University
      • • School of Applied Chemical Engineering
      • • Division of Applied Bioscience and Biotechnology
      Gwangju, Gwangju, South Korea
  • 2004–2007
    • Korea Institute of Machinery and Materials
      Sŏul, Seoul, South Korea
  • 1998–2006
    • Yonsei University
      • Department of Physics
      Sŏul, Seoul, South Korea
  • 1999–2003
    • National Institute of Standards and Technology
      • NIST Center for Neutron Research
      Gaithersburg, MD, United States
  • 1999–2002
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 1998–2001
    • National Cancer Center Korea
      Kōyō, Gyeonggi Province, South Korea
  • 1998–1999
    • Seoul Women's University
      Sŏul, Seoul, South Korea