• Title/Summary/Keyword: $LiCoO_{2}$

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A Molecular Study of Sopungsungi-won(Shufengshunqiyuan) about Regulation of PPARs in Mouse NMu2Li Liver Cells and C2C12 Skeletal Muscle Myogenic Progenital Cells (소풍순기원(疏風順氣元)이 mouse의 NMu2Li 간세포와 C2C12 골격근세포에서 PPARs 조절의 분자기전에 미치는 영향)

  • Oh, Young-Jin;Shin, Soon-Shik;Yoon, Mi-Chung;Kim, Bo-Kyung
    • Journal of Oriental Neuropsychiatry
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    • v.20 no.1
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    • pp.147-164
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    • 2009
  • Objectives : We investigated the effects of Sopungsungi-won(Shu!engshunqiyuan) (SSEx1, SSEx2) to treat the metabolic syndrome by the molecular mechanism of regulation of PPAR and modulation of mitochondrial MCAD, VLCAD mRNA expression. Methods : Mouse NMu2Li liver cells and C2C12 skeletal muscle myogenic progenital cells were transiently transfected with expression plasmids for PPAR(PPAR${\alpha}$, PPAR${\delta}$), a luciferase reporter gene construct containing 3 copies of the PPRE from the rat acyl-CoA oxidase gene and ${\beta}$-galactosidase gene. Cells were treated with several concentrated kinds of SSEx1, SSEx2 at the initial time of culture and analyzed PPAR${\alpha}$, PPAR${\delta}$ reporter gene activity using spectrophotometer (405 nm). Total RNA was extracted from SSEx1, SSEx2 and measured mRNA levels of mitochondrial MCAD, VLCAD. Representative RT-PCR bands are shown. Results : 1. SSEx1 increased the expression of PPAR${\alpha}$ reporter gene activities at 0.1 ${\mu}$g/ml (p${\mu}$g/ml (p<0.05), SSEx2 at 0.1 ${\mu}$g/ml (p${\mu}$g/ml (p<0.05) significantly in NMu2Li liver cell lines. 2. SSEx1 increased the expression of PPAR${\alpha}$ reporter gene activities at 1 ${\mu}$g/ml (p${\mu}$g/ml (p${\alpha}$ reporter gene activities in C2C12 skeletal muscle cells. 4. SSEx1 increased the modulation of mitochondrial MCAD mRNA expression (p<0.05) significantly in NMu2Li liver cell lines. 5. SSEx1, SSEx2 both increased the modulation of mitochondrial MCAD mRNA expression (p<0.05) significantly in C2C12 skeletal muscle cells. Conclusions : These results show the SSEx1, SSEx2 can be used as therapeutic agent for metabolic syndrome and it's molecular mechanisms of PPAR more contribute to the activation of PPAR${\alpha}$ then PPAR${\delta}$ reporter gene activities and it's total RNA more contribute to the modulation of mitochondrial MCAD then VLCAD mRNA expression.

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Membrane contactor and Carbon Dioxide Separation

  • 이규호
    • Proceedings of the Membrane Society of Korea Conference
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    • 2002.07a
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    • pp.59-101
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    • 2002
  • PVDF is good material for a hollow fiber membrane with high porosity and excellent hydrophobicity. Asymmetric PVDF hollow fiber membranes were prepared by the Loeb-Sourirajan phase inversion method. Asymmetric PVDF hollow fiber membranes could be controlled in pore size and porosity using various additives(LiCl, ZnCl$_2$) and internal coagulants (water, EtOH/water, and DMAc/water mixture). $CO_2$removal efficiency of asymmetric PVDF hollow fiber membranes was 1.2 times high than that of commercialized PP hollow fiber membranes at MEA 5wt% solution. $CO_2$flux of asymmetric PVDF hollow fiber membranes was 2.5 times higher than that of commercialized PP hollow fiber membranes. $CO_2$removal efficiency and absorption rate of asymmetric PVDF hollow fiber membranes were 30 times higher than those of packed column at absorbent $H_2O$. $CO_2$flux of asymmetric PVDF hollow fiber membranes at MEA 5wt% solution was 48 times higher than that of pure water. In the case of MEA 5wt% solution used as an absorbent, the $CO_2$absorption rate and removal efficiency of PVDF hollow fiber membrane were 2.3 times higher than that of a packed column.

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Synthesis and Characterization of Cathode Materials for the Lithium Secondary Batteries by Spray Drying Method

  • Oh, Si-Hyoung;Jeong, Woon-Tae;Cho, Won-Il;Cho, Byung-Won
    • Journal of the Korean Electrochemical Society
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    • v.8 no.1
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    • pp.42-46
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    • 2005
  • It has been known that the synthesis of the cathode materials for the lithium rechargeable batteries by the sol-gel process has many advantages over the conventional solid-state method. It has been, however, a continuing issue that new additional steps should be introduced to commercialize this process. In this work, spray drying was introduced to the existing sol-gel process as a continuous mass production method of the pre-heat treatment precursor materials. The precursors of $LiCoO_2$ and $LiNi_{0.8}Co_{0.2}O_2$ were continuously produced through spray drying from the solution containing stoichiometric amount of lithium, cobalt, and nickel sources as well as a chelating agent. The process variables, such as pH of the starting solution, spray drying conditions, and calcination conditions were optimized. The XRD pattern for the synthesized material indicated a good crystallinity with a layered structure.

Fabrication and Characterization of Wavelength Conversion Device with Periodically Poled Ridge-type Waveguide in MgO:LiNbO3 (주기적으로 분극 반전된 MgO:LiNbO3를 이용한 리지형 광도파로 파장가변 소자 제작 및 특성)

  • Lee, H.M.;Yang, W.S.;Kim, W.K.;Lee, H.Y.;Jeong, W.J.;Kwon, S.W.;Koo, K.H.;Song, M.G.
    • Korean Journal of Optics and Photonics
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    • v.19 no.3
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    • pp.199-207
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    • 2008
  • Wavelength converting devices with a ridge-type waveguide in periodically poled $MgO:LiNbO_3$ are made and characterized. The experimental results are compared with theoretical analysis on the effects of waveguide dimension and duty ratio of the periodically poled structure. To show the relationship of the conversion efficiency to those factors, a new measurement system is configured. That experimental results show that the center wavelength, normalized conversion efficiency and full width half maximum of the conversion efficiency curve are 1067.45 nm, 90.7%/$Wcm^2$ and 0.17 nm, respectively. Also, the estimated results of the duty period and full width half maximum of the conversion efficiency from theoretical calculations agreed well with experimental results with the errors of 0.016 ${\mu}m$ and 0.01 nm.

An Electrochemical Study on the Carbon Black Conductor Prepared by Plasma Pyrolysis of Methane (메탄 플라즈마 분해에 의해 제조된 카본블랙 도전재의 전기화학적 특성에 대한 연구)

  • Yoon, Se-Rah;Lee, Joong-Kee;Cho, Won-Ihl;Baek, Young-Soon;Ju, Jae-Beck;Cho, Byung-Won
    • Journal of the Korean Electrochemical Society
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    • v.6 no.1
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    • pp.6-12
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    • 2003
  • Plasma carbon black(PB) which prepared by plasma pyrolysis of methane was treated at 800, 1300 and $2100^{\circ}C$ under $2\times10^{-2}$ torr. Four different samples including raw PB were added to $LiCoO_2$, cathode active material of lithium secondary battery, to investigate effects of properties of plasma black as conductors on electrochemical characteristics. Based on our experimental results, PB conductors with low amount of surface functional groups and high electrical conductivity enhanced the cyclability and the initial discharge capacity. However, deterioration of rate capability and cyclability were observed (or the plasma black treated at $2100^{\circ}C$ For the plasma black conductor prepared from plasma pyrolysis, the effects of properties of carbon black on electrochemical characteristics were combined results of changes in electrical conductivity and structural properties such as agglomeration of plasma black. The conductivity of plasma black increased with treatment temperature, while dispersion of plasma black decreased. As a result, the high cyclability of cell was observed at $800^{\circ}C$ of heat treatment temperature.

Improvement of Electrochemical Properties and Thermal Stability of a Ni-rich Cathode Material by Polypropylene Coating

  • Yoo, Gi-Won;Son, Jong-Tae
    • Journal of Electrochemical Science and Technology
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    • v.7 no.2
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    • pp.179-184
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    • 2016
  • The interface between the surface of a cathode material and the electrolyte gives rise to surface reactions such as solid electrolyte interface (SEI) and chemical side reactions. These reactions lead to increased surface resistance and charge transfer resistance. It is consequently necessary to improve the electrochemical characteristics by suppressing these reactions. In order to suppress unnecessary surface reactions, we coated cathode material using polypropylene (PP). The PP coating layer effectively reduced the SEI film that is generated after a 4.3 V initial charging process. By mitigating the formation of the SEI film, the PP-coated Li[(Ni0.6Co0.1Mn0.3)0.36(Ni0.80Co0.15Al0.05)0.64)]O2(NCS) electrode provided enhanced transport of Li+ ions due to reduced SEI resistance (RSEI) and charge transfer resistance (Rct). The initial charge and discharge efficiency of the PP-coated NCS electrode was 96.2 % at a current density of 17 mA/g in a voltage range of 3.0 ~ 4.3 V, whereas the efficiency of the NCS electrode was only 94.7 %. The presence of the protective PP layer on the cathode improved the thermal stability by reducing the generated heat, and this was confirmed via DSC analysis by an increased exothermic peak.

Effect of ZnO on Low Temperature Sintering of PMN-PNN-PZT Ceramics (ZnO가 PMN-PNN-PZT 세라믹스의 저온소결에 미치는 영향)

  • Lee, Sang-Ho;Yoo, Ju-Hyun;Hong, Jae-Il;Ryu, Sung-Lim
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.32-33
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    • 2006
  • In this study, in order to develop multilayer ceramic actuator for ultrasonic nozzle and ultrasonic vibrator, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3$. $Na_2CO_3$ and ZnO as sintering aids. And then, their piezoelectric and dielectric properties according to the amount of ZnO addition were investigated. The addition of ZnO improved density, dielectric constant, electromechanical coupling factor, mechanical quality factor and piezoelectric d constant of PMN-PNN-PZT ceramics due to the increase of sinterability and accepter doping effect. Electromechanical coupling factor and mechanical quality factor of PMN-PNN-PZT ceramics increased with ZnO amount up to 0.4wt% and then decreased. At the sintering temperature of $900^{\circ}C$ and 0.4wt% ZnO addition, density, dielectric constant, electromechanical coupling factor, mechanical quality factor and piezoelectric d constant showed the optimum value of 7.876g/$cm^2$, 1299, 0.612, 1151 and 369pC/N, respectively.

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Dielectric and Piezoelectric Characteristics of PMN-PNN-PZT Ceramics with the methods of $MnO_2$ additon ($MnO_2$ 첨가방법에 따른 PMN-PNN-PZT 세라믹스의 유전 및 압전특성)

  • Kim, Do-Hyung;Kim, Kook-Jin;Yoo, Ju-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.255-256
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    • 2007
  • In the study, in order to develop low temperature sintering ceramics for multilayer piezoelectric actuator, PMN-PNN-PZT ceramics were fabricated using $Na_2CO_3,\;Li_2CO_3$ as sintering aids and their dielectric and piezoelectric properties were investigated according to the variations of $MnO_2$ as additives and sintering aids. At the sintering temperature of $900^{\circ}C$ and 0.1wt% $MnO_2$ as sintering aids, density, electromechanical coupling factor$(k_p)$, mechanical quality factor$(Q_m)$, piezoelectric constant$(d_{33})$, and dielectric constant $({\varepsilon}_r)$ showed the optimum value of $7.87[g/cm^3]$, 0.61, 1131, 1127 and 376, respectively, for multilayer piezoelectric actuator application.

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Electrochemical Performances of Lithium-ion Polymer Battery with Polyoxyalkylene Glycol Acrylate-based Gel Polymer Electrolyte (Polyoxyalkylene Glycol Acrylate기 Gel Polymer Electrolyte를 적용한 리튬이온폴리머전지의 전기화학적 특성)

  • Kim, Hyun-Soo;Kim, Sung-Il;Na, Seong-Hwan;Moon, Seong-In
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.2
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    • pp.142-147
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    • 2005
  • In this work, a gel polymer electrolyte (GPE) was prepared using polyoxyalkylene glycol acrylate (POAGA) as a macromonomer LiCoO$_2$/GPE/graphite cells were prepared and their electrochemical properties were evaluated at various current densities and temperatures. The ionic conductivity of the GPE was more than 6.2${\times}$10$^{-3}$ S$.$$cm^{-1}$ / at room temperature. The GPE had good electrochemical stability up to 4.5 V vs. Li/Li$^{+}$. POAGA-based cells were showed good electrochemical performances such as rate capability, low-temperature performance, and cycleability. The cells, also, passed a safety test such as the overcharge and nail-penetration test.t.