Surface currents from hourly variations of suspended particulate matter from Geostationary Ocean Color Imager data

Park, Kyung-Ae,Lee, Min-Sun,Park, Ji-Eun,Ullman, David,Cornillon, Peter C.,Park, Young-Je TaylorFrancis 2018 International journal of remote sensing Vol.39 No.6

<P>Surface currents in Korean coastal regions were obtained using the maximum cross-correlation method applied to hourly suspended particulate matter images from the Geostationary Ocean Color Imager. Preliminary current vectors were filtered out by applying a series of quality-control procedures. The current vectors resulting from the tests were compared with the currents from a numerical model with tide and wind field. It was found that the estimated currents were more similarly to the currents caused by both tide and wind. A high degree of discrepancy was detected in regions of strong tidal currents, where the fundamental assumption of horizontal movement was limited due to the dominant vertical tidal mixing in the shallow region. The hourly rotations of the current vectors within a day were clarified by a comparison of the time-varying orientation angles of tidal ellipses. This study emphasized how to understand the short-term surface flows from hourly high-resolution geostationary satellite images.</P>

Synthesis and Electro-Optic Properties of Novel Polyester Containing Dioxybenzylidenecyanoacetate as a NLO-Chromophore

Lee, Ga-Young,Won, Dong-Seon,Lee, Ju-Yeon TaylorFrancis 2009 Molecular Crystals and Liquid Crystals Vol.504 No.1

<P> A novel polyester (4) containing dioxybenzylidenecyanoacetate group as a NLO-chromophore was prepared and characterized. Polyester 4 was soluble in common organic solvents such as acetone and DMSO. Polymer 4 showed thermal stability up to 280°C in TGA thermogram with Tg value measured from DSC thermogram near 108°C. The SHG coefficient (d33) of poled polymer film at the 1064 nm fundamental wavelength was around 3.54 × 10-9 esu. The dipole alignment exhibited a thermal stability up to near Tg and no significant SHG decay was observed below 95°C due to the partial main-chain character of polymer structure, which was acceptable for NLO device applications.</P>

Artificial control maturation of porcine oocyte by dibutyryl cyclicAMP

Zhao, Ming-Hui,Jin, Yong-Xun,Lee, Seul-Ki,Kim, Nam-Hyung,Cui, Xiang-Shun TaylorFrancis 2014 Animal cells and systems Vol.18 No.1

<P>In this study, we investigated the effects of various durations of dibutyryl cyclic AMP (dbcAMP) treatment on the in vitro maturation (IVM) and subsequent development of parthenogenetically activated embryos. Immature porcine oocytes were cultured with or without 1 mM dbcAMP during the first 20, 28, or 36 h of culture, and then incubated for an additional 24 h without dbcAMP. The expression of <I>Wee1B, Myt</I>, and <I>Cdc25B</I> and the level of maturation promoting factor (MPF) in metaphase II oocytes were analyzed by real-time PCR (qRT-PCR) and enzyme linked immunosorbent assay (ELISA), respectively. The distribution of actin microfilaments in oocytes was also assessed. Subsequently, apoptotic cells in blastocysts from each group were visualized by transferase-mediated dUTP nick-end labeling staining. Results showed that oocytes extruded the first polar body between 12 and 18 h after being released from dbcAMP. MPF activity in oocytes at 28 + 24 h and 36 + 24 h after dbcAMP treatment was higher than that in the control group. Significantly more blastocysts were present among embryos in 28 + 24 h (54.28% vs. 39.11%, <I>P</I> < 0.05) and 36 + 24 h (47.24% vs. 32.94%, <I>P</I> < 0.05) groups than among embryos cultured in the absence of dbcAMP. However, the number of total and apoptotic cells was not significantly different between groups. The distribution of actin microfilaments was abnormal in oocytes cultured for 60 h without dbcAMP. In addition, the expression of <I>Wee1B, Myt</I>, and <I>Cdc25B</I> was higher in the control group at 44 h than in the dbcAMP group, but there were no differences in expression at the other time points. In conclusion, dbcAMP treatment delays oocyte maturation and maintains oocyte quality.</P>

Synthesis and Nonlinear Optical Properties of Novel Polyester Containing Tricyanovinylthiophene with Enhanced Thermal Stability of Second Harmonic Generation

Lee, Ga-Young,No, Hyo Jin,Lee, Ju-Yeon TaylorFrancis 2009 Molecular Crystals and Liquid Crystals Vol.504 No.1

<P> A novel Y-type polyester (7) containing 1-(2,4-dioxyethoxy)phenyl-2-{5-(1,2,2-tricyanovinyl)-2-thiophenyl)}ethenyl groups as NLO-chromophores was synthesized and characterized. Polymer 7 was soluble in common organic solvents such as DMF and DMSO. It showed thermal stability up to 300°C in TGA with Tg value obtained from DSC near 134°C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at the 1,560 nm fundamental wavelength was around 6.74 × 10-9 esu. The dipole alignment exhibited high thermal stability and there was no SHG decay below Tg due to the partial main-chain character of polymer structure, which was acceptable for NLO device applications.</P>

Photovoltaic Properties of Dye-Sensitized Solar Cells using Metallophthalocyanines with Poly(ethylene glycol) Electrolytes

Lee, Jin-Kook,Jang, Sung-Il,Kim, Young-Geun,Jang, Young-Wook,Jeong, Bo-Hwa,Kim, Ji-Un,Jung, Ki-Suck,Kim, Mi-Ra TaylorFrancis 2008 MOLECULAR CRYSTALS AND LIQUID CRYSTALS - Vol.491 No.1

<P> Dye-sensitized solar cells (DSSCs) were prepared with a poly(ethylene glycol) (PEG) electrolyte using various metallophthalocyanines (MPcs) as an additive. The DSSC device using MPcs has higher power conversion efficiency than that without MPcs, due to decrease of electron transfer distance by the interface adsorption between TiO2 film and PEG electrolyte. The best result on power conversion efficiency was 4.18% in DSSC device using InOHPc. The open-circuit voltage (Voc) was 0.70 V, the short-circuit current density (Jsc) was 10.20 mA/cm2, and the Fill Factor (FF) was 0.58. The addition of MPcs as an additive is useful to improve the performances of DSSC devices such as Voc, Jsc, and power conversion efficiency.</P>

Synthesis and Photophysical Properties of Luminescent Lanthanide Complexes Based on Dansyl- N -Methyl-Aminobenzoic Acid for Advanced Photonics Applications

Roh, Soo-Gyun,Kim, Yong Hee,Beak, Nam Seob,Hong, Kyong-Soo,Kim, Hwan Kyu TaylorFrancis 2006 MOLECULAR CRYSTALS AND LIQUID CRYSTALS - Vol.446 No.1

<P>Novel luminescent Ln(III)-chelated complexes based on dansyl-N-methyl-aminobenzoic acid exhibited the strong near IR emission bands of the characteristic 4 I 13/2 ? 4 I 15/2 transition of Er(III) ion around 1530 nm and the characteristic 4 F 3/2 ? 4 F 9/2 , 4 F 3/2 ? 4 F 11/2 and 4 F 3/2 ? 4 F 13/2 transitions of Nd(III) ion around 880, 1060 and 1330 nm. Their photoluminescence intensity depends on the degree of the spectral overlap between the emission band of the ligand and the absorption band of lanthanide(III) ion. The radiative life times of Er(III) and Nd(III) ions in the lanthanide(III) complex films were estimated to be 1.6 and 1.2 µs, respectively.</P>

Effects of epigallocatechin-3-gallate on thermogenesis and mitochondrial biogenesis in brown adipose tissues of diet-induced obese mice

Lee, Mak-Soon,Shin, Yoonjin,Jung, Sunyoon,Kim, Yangha TaylorFrancis 2017 Food & nutrition research Vol.61 No.-

<P><B>ABSTRACT</B></P><P><B>Background</B>: Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea and has been considered a natural agent that can help to reduce the risk of obesity.</P><P><B>Objective</B>: The aim of this study was to investigate the effects of EGCG on thermogenesis and mitochondrial biogenesis in brown adipose tissue (BAT) of diet-induced obese mice.</P><P><B>Methods</B>: Male C57BL/6J mice were provided a high-fat diet for 8 weeks to induce obesity, following which they were divided into two groups: one on a high-fat control diet and the other on a 0.2% EGCG (w/w)-supplemented high-fat diet for another 8 weeks.</P><P><B>Results</B>: The EGCG-supplemented group showed decreased body weight gain, and plasma and liver lipids. EGCG-fed mice exhibited higher body temperature and mitochondrial DNA (mtDNA) content in BAT. The messenger RNA levels of genes related to thermogenesis and mitochondrial biogenesis in BAT were increased by EGCG. Moreover, adenosine monophosphate-activated protein kinase (AMPK) activity in BAT was stimulated by EGCG.</P><P><B>Conclusions</B>: The results suggest that EGCG may have anti-obesity properties through BAT thermogenesis and mitochondria biogenesis, which are partially associated with the regulation of genes related to thermogenesis and mitochondria biogenesis, and the increase in mtDNA replication and AMPK activation in BAT of diet-induced obese mice.</P>

Synthesis of Polythiophenes with Electron-Donating Side-Chain and their Application to Organic Thin-Film Transistors

Paek, Sunhee,Lee, Jaemin,Ko, Jung Min,Lim, Hyun Seok,Lim, Jongsun,Cho, Seung Hyun,Lee, Jun Young,Lee, Changjin TaylorFrancis 2009 Molecular Crystals and Liquid Crystals Vol.504 No.1

<P> Thiophene-based π-conjugated polymers have been widely used in p-channel OTFTs due to their high charge carrier mobility. SPQT-12 which has dodecylsulfanyl side-chain was synthesized by Stille polymerization. The polymer was characterized by 1H NMR, GPC, UV-Vis spectroscopy, and cyclic voltammetry. Molecular weight (Mn) of SPQT-12 was 10,000 (PDI = 1.7), and SPQT-12 were readily soluble in common organic solvents. In the film state, SPQT-12 showed absorption with &lgr;max at 553 nm and optical band gap of 1.87 eV. A mobility of 1.0 × 10-3 cm2/Vs, an on/off ratio of 5.8 × 103 and threshold voltage of -11 V have been obtained with OTFTs using SPQT-12.</P>

Optimization of Liquid Crystal Concentration in the Dye-Sensitized Solar Cell for High Efficiency

Kim, H. K.,Lee, M. J.,Jin, S. -H.,Lee, G. -D. TaylorFrancis 2009 Molecular Crystals and Liquid Crystals Vol.510 No.1

<P> In this paper we optimize the liquid crystal (LC) concentration in the polymer electrolyte for high power conversion efficiency (PCE) of the DSSC. We measured the PCE of the dye-sensitized solar cell (DSSC) as a function of the concentration rate of the liquid crystal, E7. The concentration of the LC has been mixed with 0, 5, 10, 15, and 20 wt% in the polymer electrolyte, respectively. In addition, we also measured current-voltage curve for measuring the fill factor of the DSSC in each concentration of the LC material. As a result, we found that the DSSC with 10 wt% of the LC concentration in polymer electrolyte can provide maximum PCE value for high photovoltaic performance in the experiment.</P>

Anomalous transport phenomena in Weyl metal beyond the Drude model for Landauʼs Fermi liquids

Kim, Ki-Seok,Kim, Heon-Jung,Sasaki, M,Wang, j-f,Li, L TaylorFrancis 2014 SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS Vol.15 No.6

<P>Landauʼs Fermi-liquid theory is the standard model for metals, characterized by the existence of electron quasiparticles near a Fermi surface as long as Landauʼs interaction parameters lie below critical values for instabilities. Recently this fundamental paradigm has been challenged by the physics of strong spin–orbit coupling, although the concept of electron quasiparticles remains valid near the Fermi surface, where Landauʼs Fermi-liquid theory fails to describe the electromagnetic properties of this novel metallic state, referred to as Weyl metal. A novel ingredient is that such a Fermi surface encloses a Weyl point with definite chirality, referred to as a chiral Fermi surface, which can arise from breaking of either time reversal or inversion symmetry in systems with strong spin–orbit coupling, responsible for both the Berry curvature and the chiral anomaly. As a result, electromagnetic properties of the Weyl metallic state are described not by conventional Maxwell equations but by axion electrodynamics, where Maxwell equations are modified with a topological-in-origin spatially modulated [FORMULA OMISSION] term.</P><P>This novel metallic state was realized recently in Bi[FORMULA OMISSION]Sb<SUB><I>x</I></SUB> around [FORMULA OMISSION] under magnetic fields, where the Dirac spectrum appears around the critical point between the normal semiconducting ([FORMULA OMISSION]) and topological semiconducting phases ([FORMULA OMISSION]) and the time reversal symmetry breaking perturbation causes the Dirac point to split into a pair of Weyl points along the direction of the applied magnetic field for a very strong spin–orbit coupled system.</P><P>In this review article, we discuss how the topological structure of both the Berry curvature and the chiral anomaly (axion electrodynamics) gives rise to anomalous transport phenomena in [FORMULA OMISSION]Sb<SUB><I>x</I></SUB> around [FORMULA OMISSION] under magnetic fields, thus modifying the Drude model of Landauʼs Fermi liquids.</P>