• Title/Summary/Keyword: PO2

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Study on LiFePO4 Composite Cathode Materials to Enhance Thermal Stability of Hybrid Capacitor (하이브리드 커패시터의 열안정성 개선을 위한 LiFePO4 복합양극 소재에 관한 연구)

  • Kwon, Tae-Soon;Park, Ji-Hyun;Kang, Seok-Won;Jeong, Rag-Gyo;Han, Sang-Jin
    • Korean Chemical Engineering Research
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    • v.55 no.2
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    • pp.242-246
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    • 2017
  • The application of composite cathode materials including $LiFePO_4$ (lithium iron phosphate) of olivine crystal structure, which has high thermal stability, were investigated as alternatives for hybrid battery-capacitors with a $LiMn_2O_4$ (spinel crystal structure) cathode, which exhibits decreased performance at high temperatures due to Mn-dissolution. However, these composite cathode materials have been shown to have a reduction in capacity by conducting life cycle experiments in which a $LiFePO_4$/activated carbon cell was charged and discharged between 1.0 V and 2.3 V at two temperatures, $25^{\circ}C$ and $60^{\circ}C$, which caused a degradation of the anode due to the lowered voltage in the anode. To avoid the degradation of the anode, composite cathodes of $LiFePO_4/LiMn_2O_4$ (50:50 wt%), $LiFePO_4$/activated carbon (50:50 wt%) and $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ (50:50 wt%) were prepared and the life cycle experiments were conducted on these cells. The composite cathode including $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ of layered crystal structure showed stable voltage behavior. The discharge capacity retention ratio of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ was about twice as high as that of a $LiFePO_4/LiMn_2O_4$ cell at thermal stability experiment for a duration of 1,000 hours charged at 2.3 V and a temperature of $80^{\circ}C$.

Gasification Characteristics to $^{14}CO_2\;of\;^{14}C$ Radionuclide Desorbed from Spent Resin by Phosphate Solutions (월성 원전발생 폐수지로부터 제거된 $^{14}C$ 핵종의 인산용액을 이용한 $^{14}CO_2$로의 기체화 특성)

  • Yang, Ho-Yeon;Won, Jang-Sik;Choi, Young-Ku;Park, Geun-Il;Kim, In-Tae;Kim, Kwang-Wook;Song, Kee-Chan;Park, Hwan-Seo
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.4 no.4
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    • pp.311-320
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    • 2006
  • Removal characteristics of $H^{14}CO_3$ ion from IRN-150 mixed resin contaminated with $^{14}C$ radionuclide and a gasification behavior of $^{14}C$ radionuclide to $^{14}CO_2$ were investigated. The stripping solutions used for the removal of $^{14}C$ from spent resin were $NaNO_3,\;Na_3PO_4,\;NH_4H_2PO_4,\;H_3PO_4$. The influence of stripping solution concentration on the desorption characteristics of inactive $HCO_3$ ion into stripping solution from IRN-150 mixed resin and the gasification of this ion to $CO_2$ was analyzed. The gasification behavior to $CO_2$ by using NaOH, $HNO_3$, HCl was also compared to that of phosphate solution. Real spent resin stored in Wolsung nuclear power plant was used to evaluate the gasification characteristics of $^{14}C$ radionuclide to $^{14}CO_2$. Gamma radionuclides such as $^{137}Cs,\;^{60}Co$ in residual striping solutions after desorption experiment were analyzed.

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Reuse and Concentration of Sewage by Forward Osmosis Using Fertilizer as Draw Solution (비료 유도용액의 정삼투를 이용한 하수의 재이용 및 농축)

  • Kim, Seung-Geon;Lee, Ho-Won
    • Applied Chemistry for Engineering
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    • v.30 no.1
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    • pp.122-131
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    • 2019
  • In order to reuse and concentrate the sewage, a forward osmosis using fertilizer as draw solution was applied. Sewage-1, which is the supernatant after settling for 30 minutes for the primary settling basin influent, and Sewage-2, which is the supernatant after settling for 30 minutes for the effluent, and Sewage-3, which is the filtrate filtered through a $1{\mu}m$ cartridge filter for the effluent were tested. Eight draw solutions of $NH_4H_2PO_4$, KCl, $KNO_3$, $NH_4Cl$, $(NH_4)_2HPO_4$, $NH_4NO_3$, $NH_4HCO_3$, and $KHCO_3$ were used in consideration of osmotic pressure, solubility and pH. In the case of Sewage-3, the permeate flux was almost similar to that of the discharge water of the sewage treatment plant, and was larger than that of Sewage-1 and Sewage-2. $NH_4H_2PO_4$ was the smallest, and $NH_4NO_3$ was the largest in the specific reverse solute flux. $NH_4H_2PO_4$ was found to be most useful for the reuse and concentration of sewage because it contains nitrogen and phosphorus, which are the major components of fertilizer, as well as low specific reverse solute flux. When $NH_4H_2PO_4$ was used as the draw solution, the concentration factor after 24 hours for Sewage-3 was 1.72.

Modeling the electric transport of HCl and H3PO4 mixture through anion-exchange membranes

  • Koter, Stanislaw;Kultys, Monika;Gilewicz-Lukasik, Barbara
    • Membrane and Water Treatment
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    • v.2 no.3
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    • pp.187-205
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    • 2011
  • The electric transport of the mixture of hydrochloric and phosphoric acids through strong base (Neosepta ACM) and weak base (Selemion AAV) anion-exchange membranes was investigated. The instantaneous efficiency of HCl removal from the cathode solution, $CE_{Cl}$, with and without $H_3PO_4$ was determined. It was found that $CE_{Cl}$ was 0.8-0.9 if the number of moles of elementary charge passed through the system, $n_F$, did not exceed ca. 80% of the initial number of HCl moles in the cathode solution, $n_{Cl,ca,0}$. The retention efficiency of $H_3PO_4$ in that range was close to one. The transport of acid mixtures was satisfactorily described by a model based on the extended Nernst-Planck and Donnan equations for $n_F$ not exceeding $n_{Cl,ca,0}$. Among the tested model parameters, most important were: concentration of fixed charges, the porosity-tortuosity coefficient, and the partition coefficient of an undissociated form of $H_3PO_4$. For the both membranes, the obtained optimal values of fixed charge concentration, $\bar{c}_m$, were up to 40% lower than the literature values of $\bar{c}_m$ obtained from the equilibrium measurements. Regarding the $H_3PO_4$ equilibria, it was sufficient to consider $H_3PO_4$ as a monoprotic acid.

Improving Electrochemical Properties of LiFePO4 by Doping with Gallium

  • Nguyen, Van Hiep;Park, Ju-Young;Gu, Hal-Bon
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.6
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    • pp.320-323
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    • 2014
  • Ga-doped $LiFePO_4$ cathode materials were synthesized using a hydrothermal method. The microstructural characteristics and electrochemical performances were systematically investigated using field emission scanning electron microscopy, high-resolution X-ray diffraction, energy dispersive X-ray spectroscopy, charge-discharge cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Among the as-prepared samples, $LiFe_{0.96}Ga_{0.04}PO_4$ demonstrates the best electrochemical properties in terms of discharge capacity, electrochemical reversibility, and cycling performance with an initial discharge capacity of $125mAh\;g^{-1}$ and high lithium ion diffusion coefficient of $1.38{\times}10^{-14}cm^2s^{-1}$ (whereas for $LiFePO_4$, these were $113mAh\;g^{-1}$ and $8.09{\times}10^{-15}cm^2\;s^{-1}$, respectively). The improved electrochemical performance can be attributed to the facilitation of Li+ ion effective diffusion induced by $Ga^{3+}$ substitution.

Cloning and characterization of ADP-ribosylation factor 1b from the olive flounder Paralichthys olivaceus

  • Son, So-Hee;Jang, Jin-Hyeon;Jo, Hyeon-Kyeong;Chung, Joon-Ki;Lee, Hyung-Ho
    • Fisheries and Aquatic Sciences
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    • v.20 no.6
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    • pp.10.1-10.7
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    • 2017
  • Small GTPases are well known as one of the signal transduction factors of immune systems. The ADP-ribosylation factors (ARFs) can be classified into three groups based on the peptide sequence, protein molecular weight, gene structure, and phylogenetic analysis. ARF1 recruits coat proteins to the Golgi membranes when it is bound to GTP. The class I duplicated ARF gene was cloned and characterized from the olive flounder (Paralichthys olivaceus) for this study. PoARF1b contains the GTP-binding motif and the switch 1 and 2 regions. PoARF1b and PoARF1b mutants were transfected into a Hirame natural embryo cell to determine the distribution of its GDP/GTP-bound state; consequently, it was confirmed that PoARF1b associates with the Golgi body when it is in a GTP-binding form. The results of the qPCR-described PoARF1b were expressed for all of the P. olivaceus tissues. The authors plan to study the gene expression patterns of PoARF1b in terms of immunity challenges.

Characterization of G9 genotype porcine rotavirus isolated in Korea (국내 양돈장에서 분리한 G9형 돼지로타바이러스의 특성)

  • Wang, Jun-Hui;Lee, Seung-Chul;Kang, Shien-Young
    • Korean Journal of Veterinary Service
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    • v.35 no.2
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    • pp.83-90
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    • 2012
  • Porcine rotaviruses are the most common causes of viral gastroenteritis in piglets around the world. The major G genotypes of porcine rotaviruses causing diarrhea were G4, G5 and G11 genotypes. Recently, G9 genotype rotaviruses were problemed at swine farms and frequently recognized from diarrheic piglets. In this study, a porcine rotavirus (PoRV-1) was isolated from piglet showing diarrhea using MA104 cells and confirmed as rotavirus by electron microscopy, genomic RNA electropherotyping and indirect immunofluorescence antibody tests. The nucleotide sequence of the VP7 gene of PoRV-1 was determined and compared with those of other genotype rotavirus strains from other parts of the world. Also, the nucleotide sequences of VP4, VP6 and NSP4 genes of PoRV-1 were determined and compared with those of other rotavirus strains from other countries. The results showed that the PoRV-1 isolate belonged to the G9 genotype and the P, I and E genotypes of PoRV-1 were P[23], I5 and E1, respectively. The Korean G9 PoRV-1 isolate and its nucleotide sequence data would be usefully used for the development of porcine rotavirus vaccines in near future.

Variation of the Curie Temperature in $BaTiO_3$ Doping $Cd_5(PO_4)_3Cl$ ($BaTiO_3$에서 $Cd_5(PO_4)_3Cl$의 첨가로 인한 Curie 온도변화)

  • Kim, Gwang-Chul
    • Journal of the Semiconductor & Display Technology
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    • v.10 no.1
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    • pp.95-99
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    • 2011
  • $(1-x)BaTiO_3+(x)Cd_5(PO_4)_3Cl$ ceramics were prepared by the conventional ceramic technique, i.e., solid state reaction at high temperature. The concentration of $Cd_5(PO_4)_3C$ was varied from 0.01 to 0.15 mole fraction. In order to study the phase transitions of our ceramics, the Raman scattering spectra were measured as functions of concentration x and temperature. It was found that the soluble limit of $Cd_5(PO_4)_3Cl$ in $BaTiO_3$ was the x=0.05 composition and $BaTiO_3$ phase disappeared above x=0.10. A new phase identified as $Ba_4Ti_3P_2O_{15}$ was detected in all samples of our compositions. The Curie temperature shifts up to $130^{\circ}C$ as the concentration x increases from zero to 0.05 and shift down to $95^{\circ}C$ as further increases to 0.08. For the increase of the Curie temperature, it is suggested that it can result from the inhibition of displacement of $Ti^{4+}$ in the distorted octahedron due to well dispersed $Ba_4Ti_3P_2O_{15}$ and $Cd_5(PO_4)_3Cl$ phase.

Ce3+ sensitize RE3+ (RE=Dy, Tb, Eu, Sm) doped LaPO4 nanophosphor with white emission tunability

  • Phaomei, G.;Yaiphaba, N.
    • Advances in nano research
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    • v.3 no.2
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    • pp.55-66
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    • 2015
  • Crystalline $Ce^{3+}$ co-doped $LaPO_4$:RE ($RE=Dy^{3+}$, $Tb^{3+}$, $Eu^{3+}$, $Sm^{3+}$) and mix doped rare earth ions of $Dy^{3+}$, $Tb^{3+}$ and $Eu^{3+}$ were prepared by the polyol method at $150^{\circ}C$. Strongly enhance luminescence intensity is obtained with the co-doping of $Ce^{3+}$ with $LaPO_4$:$Dy^{3+}$ and $LaPO_4$:$Tb^{3+}$ due to charge transfer (CT) occurring from $Ce^{3+}$ to $Dy^{3+}$ and $Ce^{3+}$ to $Tb^{3+}$, where as there is no significant changes in luminescence intensity of $Ce^{3+}$ co-doped $Eu^{3+}$ and $Sm^{3+}$ doped $LaPO_4$ samples. The luminescence color can be tuned from green to white by varying the excitation wavelength for the mix ions $Ce^{3+}$, $Dy^{3+}$, $Tb^{3+}$ and $Eu^{3+}$ doped with $LaPO_4$.

Yield Increase and Energy Saving Effect on Plastic Greenhouse Covered with Polyolefin Film (PO필름 피복 온실의 수량 증대 및 에너지 절감 효과)

  • Moon, Jong Pil;Park, Seok Ho;Kim, Jin Gu;Lee, Jae Han;Kang, Youn Koo;Lim, Mi Young;Kim, Hye Min
    • Journal of Bio-Environment Control
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    • v.29 no.4
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    • pp.428-439
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    • 2020
  • This study was carried out to investigate the effect of PO film on the increase of crop yield and energy saving through PO and PE film greenhouse application and comparison test. As a experimental greenhouse, two single span greenhouses (1-1 W) and two double span greenhouses (1-2 W) were used. During winter season, PO film (0.15 mm outer layer, 0.10mm inner layer) was used as a covering material of greenhouse in double layers for double-span (B15) and single-span(B21), and PE film used for double-span (B15), and single-span (B23) as a control. The experimental vegetable was tomato(Solanum lycopersicum L.) cultivated in soil and the cultivar of that was 'Happiness'. That was cultivated from December 3, 2019 to April 30, 2020. The temperature at night inside the greenhouse was maintained at 15℃, and the side and roof windows were opened to maintain 23 ~ 24℃ during the day. As a result, this study showed that the yield in single-span greenhouse(B21) covered with a PO film increased 20% and that in double-span greenhouse (B16) increased by 9% compared to the greenhouse covered with a PE film (B23, B15). Fuel consumption of the single-span greenhouse (B21) with the cover of PO film was reduced by 12.4% and that of double-span greenhouse was done by 11.5% compared to that of the PE film greenhouse (B23, B15) without any difference between them in growing state.