• Journal of Sensor Science and Technology
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• v.15 no.3
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• pp.168-172
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• 2006

Potentiometric $CO_{2}$ sensors were fabricated using a NASICON ($Na_{1+x}Zr_{2}Si_{X}P_{3-X}O_{12}$, 1.8 < x < 2.4) thick film and auxiliary layers. The powder of a precursor of NASICON with high purity was synthesized by a sol-gel method. By using the NASICON paste, an electrolyte was prepared on the alumina substrate by screen printing and then sintered at $1000^{\circ}C$ for 4 h. A series of $Na_{2}CO_{3}-CaCO_{3}$ auxiliary phases were deposited on the Pt sensing electrode. The electromotive force (emf) values were linearly dependent on the logarithm of $CO_{2}$ concentration in the range between 1,000 and 10,000 ppm. The device attached with $Na_{2}CO_{3}-CaCO_{3}$ (1:2 in mol.%) showed good sensing properties in the low temperatures.

• Analytical Science and Technology
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• v.8 no.1
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• pp.55-62
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• 1995

Tetradentate Schiff base cobalt(II) complexes such as $Co(II)_2-N$, N-bis(salicylidene)-m-phenylendiimine; [$Co(II)_2(SMPD)_2(H_2O)_4$] and $Co(II)_2-N$, N-bis(salicylidene)-p-phenylendiimine: [$Co(II)_2(SPPD)_2(H_2O)_4$], and oxygen adducted cobalt (III) complexes such as [$Co(III)_2O_2(SMPD)_2(Py)_2$] and [$Co(III)_2O_2(SPPD)_2(Py)_2$] in pyridine solutions were synthesized. It was identified that the oxygen adducted cobalt(III) complexes have hexacoordinated octahedral configuration with pyridine and oxygen from the measurement of elemental analysis, AA, IR spectra, and TGA. The redox processes were investigated for the oxygen adducted complexes in 0.1M TEAP-pyridine solution, using cyclic voltammetry on the glassy carbon electrode. The redox processes of oxygen adducted Co(III) complexes result in $$[Co(III)_2-O_2-CO(III)]\rightarrow^{e^-}[Co(III)-O_2-Co(II)]\rightarrow^{e^-}[Co(II)-O_2-Co(II)]\rightleftarrows^{e^-}[Co(II)+Co(II)+O_2{\cdot}^-]\rightleftarrows^{e^-}[Co(II)+Co(I)+O_2{\cdot}^-]\rightleftarrows^{e^-}[Co(I)+Co(I)+O_2{\cdot}^-]$$.

• Membrane Journal
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• v.27 no.2
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• pp.147-153
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• 2017

In this study, we investigated permeation properties of single gas ($N_2$, $O_2$, $CO_2$) through membranes composed of poly(ethylene oxide) (PEO) and poly(ethylene-co-vinyl acetate) (EVA) blend. The prepared membranes showed no new absorbance peaks, which indicate the physical blending of PEO and EVA by FT-IR analysis. SEM observation showed that the crystalline phase of PEO decreased with increasing EVA content in the PEO/EVA mixed matrix. DSC analysis showed that the crystallinity of the PEO/EVA blend membrane decreased with increasing EVA content. Gas permeation experiment was performed with various feed pressure (4~8 bar). The permeability increased in the following order: $N_2$ < $O_2$ < $CO_2$. The permeability of $CO_2$ in PEO/EVA blend membranes were increased with increasing feed pressure, However, the permeability of $N_2$ and $O_2$ were independent of feed pressure. On the other hand, the permeability of all the gases in PEO/EVA blend membranes increased with increasing amorphous EVA content in semi-crystalline PEO. In particular, the blend membrane with 40 wt% EVA showed $CO_2$ permeability of 64 Barrer and $CO_2/N_2$ ideal selectivity of 61.5. The high $CO_2$ permeability and $CO_2/N_2$ ideal selectivity are attributed to strong affinity between the polar ether groups of PEO or the polar ester groups of EVA and polar $CO_2$.

• KSBB Journal
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• v.25 no.6
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• pp.559-564
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• 2010

A new hydrogen-oxidizing bacterium, Aeromonas sp. strain JS-1, that can fix $CO_2$ via the reductive pentose phosphate cycle (Calvin-Benson cycle) under chemoautotrophic conditions but not photoautotrophic conditions was isolated from fresh water. Strain JS-1 showed considerable $CO_2$ fixation ability during continuous cultivation even at high $CO_2$ concentration. Strain JS-1 used $H_2$ and $CO_2$ fixation as energy and carbon sources, respectively. Carbon dioxide fixation is carried out through the Calvin-Benson cycle, in which ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is the key enzyme. Hydrogen-oxidizing chemoautotrophic Aeromonas sp. strain JS-1 exhibited remarkedly strong RubisCO [EC 4.1.1.39] activity. RubisCO was purified as an $L_8S_8$-type hexadecamer with molecular mass of 560 kDa by gel filtration. The enzyme consisted of two different subunits eight large (56 kDa) and eight small (15 kDa), as demonstrated by SDS-PAGE. The specific activity of the purified enzyme was about 3.31 unit/mg and stable up to $45^{\circ}C$. The $K_m$ values for RuBP, $CO_2$, and $Mg^{2+}$ were estimated to be 0.25 mM, 5.2 mM and 0.91 mM, respectively.

• Membrane Journal
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• v.29 no.1
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• pp.44-50
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• 2019

In this paper, we developed mixed matrix membranes (MMMs) consisting of SBS-g-POEM block-graft copolymer, ionic liquid (EMIMTFSI) and ZIF-8 nanoparticles to separate a $CO_2/N_2$ gas pair. The SBS-g-POEM is a rubbery block-graft copolymer synthesized through low-cost free-radical polymerization. The EMIMTFSI was dissolved into the SBS-g-POEM matrix and solution synthesized ZIF-8 nanoparticles were also dispersed into the copolymer matrix. The physico-chemical properties of manufactured membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD), which showed that the components were compatible with each other. The gas separation performance was confirmed by time-lag measurements showing $CO_2$ permeability of 537.0 barrer and $CO_2/N_2$ selectivity of 15.2. The result represents the EMIMTFSI and ZIF-8 nanoparticles improves the gas permeability more than two-times, without significantly sacrificing the $CO_2/N_2$ selectivity.

• Membrane Journal
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• v.21 no.2
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• pp.155-162
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• 2011

Dense tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) membranes were prepared by extrusion technique. The phase structure of the $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membranes was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Relative density of $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ tubular membrane was 94.10%. Oxygen permeation was measured at difference operating condition of feed side and permeate side in the temperature range from 700 to $950^{\circ}C$. The oxygen permeation flux of dense tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membrane reached maximum 1.37 mL/$min{\cdot}cm^2$ at $900^{\circ}C$ exposed to ambient air (feed side) and vacuum pump (permeate side).

• Nutrition Research and Practice
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• v.17 no.5
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• pp.1028-1041
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• 2023

BACKGROUND/OBJECTIVES: This study aimed to analyze the potential of school meals in South Korea as a sustainable tool to reduce carbon emissions by focusing on animal- vs. plant-based protein foods. MATERIALS/METHODS: By using a stratified proportional allocation method, 536 out of the 11,082 schools nationwide were selected including 21 kindergartens, 287 elementary-, 120 middle- and 108 high schools. A total of 2,680 meals served for 5 consecutive days (June 21-25, 2021) were collected. We analyzed the average serving amounts of protein foods (animal- vs. plant-based) per meal and then, calculated the estimated average amounts of carbon emission equivalents per meal by applying the conversion coefficients. The t-test and analysis of variance were used for statistical analyses (α = 0.05). RESULTS: The average serving amount of animal-based protein foods per meal was 12.5 g, which was approximately 3 times higher than that of plant-based ones (3.8 g) (P < 0.001); the Meat-group had the highest average amount of 17.0 g, followed by Egg-group (9.6 g), Fish-group (7.6 g), and Beans-and-Nuts-group (3.8 g) (P < 0.05). Specifically, pork (25.1 g) was ranked first, followed by poultry (19.6 g), processed meat products (18.0 g). The estimated average amount of carbon emission equivalents of animal-based protein foods per meal was 80.1 g CO₂e, which was approximately 31 times higher than that of plant-based ones (2.6 g CO₂e) (P < 0.001); the Meat-group had the highest average amount of 120.3 g CO₂e, followed by Fish-group (44.5 g CO₂e), Egg-group (25.9 g CO₂e), and Beans-and-Nuts-group (2.6 g CO₂e) (P < 0.05). Specifically, processed meat products (270.8 g CO₂e) were ranked first, followed by pork (91.7 g CO₂e), and processed fish products (86.6 g CO₂e). CONCLUSIONS: The results implied that school meals with plant-based alternatives could be a sustainable tool to improve carbon footprint.

• Journal of Nutrition and Health
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• v.27 no.5
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• pp.442-450
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• 1994

The purpose of this study was to determine the effects of 2-AAF injection time on hepatic lipid peroxide metabolism and cytochrome P450 content in Sprague-Dawley rats fed diets containing high amounts of vegetable oils or animal fats(15%, w/w). Fifty mg of 2-AAF/kg of body weight/day was injected in PEG 300 intraperitonially for 3 consecutive days after 4 or 8 weeks to rats fed corn oil(CO) or lard(LA) diet. The contents of lipid peroxide and cytochrome P450, and the activities of superoxide dismutase(SOD), glutathione peroxidase(GSH-peroxidase) and glutathione S-transferase(GSH-S-transferase) were determined in hepatic microsomal or cytosolic fraction. Microsomal thiobarbituric acid reactive substances(TBARS) and cytochrome P450 contents increased in Co group injected 2-AAF after 4weeks. Cytosolic SOD activity increased in CO group injected 2-AAF after 4 weeks and in LA group injected 2-AAF after 4 or 8 weeks. Cytosolic GSH-S-transferase activity increased in LA group compared to CO group without 2-AAF injection. GSH-S-transferase activity increased in CO group injected 2-AAF after 4 or 8 weeks and in LA group injected 2-AAF after 4 weeks. Therefore, it may be suggested that 2-AAF injection increase the contents of lipid peroxide or cytochrome P450, and detoxifying enzyme activities in rats fed CO diet for short period and in rats fed LA diet for longer period.

• Korean Chemical Engineering Research
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• v.45 no.6
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• pp.633-637
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• 2007

Electroless plating of Co-alloy thin films as capping layers for Cu interconnection has been investigated using alkali-free precursors such as $(NH_4)_2Co(SO_4)_2{\cdot}6H_2O$, $(NH_4)_2WO_4$, $(NH_4)H_2PO_4$, etc. The characteristics of the Co-alloy thin films were discussed by analyses of the effects of pH, Co-precursor concentration, and deposition temperature on the thickness and surface morphology of the films. The thickness of the Co-alloy thin films increased with increasing pH, Co-precursor concentration, and deposition temperature, similarly to the results of electroless plating of Co-alloy thin films using alkali-containing chemicals. The SEM images of the surface of the Co-alloy thin films showed that the proper ranges of pH and deposition temperature were 8.5~9.5 and $75{\sim}85^{\circ}C$, respectively. This work found a feasibility that Co-alloy thin films as capping layers for Cu interconnection could be electroless plated using alkali-free chemicals.

• Journal of the Korean Magnetics Society
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• v.19 no.2
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• pp.52-56
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• 2009

Interlayer coupling field, coercivity, magnetoresitance ratio, and magnetic sensitivity depending on the thickness of free CoFe layer for the CoFe/Cu/CoFe/IrMn multilayer are investigated. In case of CoFe layer of $30\;{\AA}$ thickness for the CoFe(t)/Cu($25\;{\AA}$)/CoFe($60\;{\AA}$)/IrMn($80\;{\AA}$) multilayer with ferromagnet/non-magnet/ferromagnet structure induced by IrMn layer, the lowest coercivity and the highest magnetic sensitivity, which is contained soft magnetic property, are observed. On the other side, in case of CoFe layer of $90\;{\AA}$ thickness, there are the highest coercivity and the lowest magnetic sensitivity. The fabricated CoFe($30\;{\AA}$)/Cu($25\;{\AA}$)/CoFe($60\;{\AA}$)]/IrMn($80\;{\AA}$) spin valve device with $2{\times}8{\mu}m^2$ patterning size are measured by two probe method, which is selected the sensing current as the longitudinal direction and the easy axis as the transversal direction. The measuring magntoresistance ratio and magnetic sensitivity of GMR-SV device having the soft magnetic property are 3.0% and 0.3%/Oe, respectively.