• Journal of Energy Engineering
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• v.25 no.1
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• pp.76-85
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• 2016

This study introduces the system layout and control strategy necessary to start and operate a fuel processor in a wide range of temperatures where a gasoline was selected as the fuel of fuel processor considering logistic support of Korea Army. The autothermal reformig(ATR) catalyst is heated to light-off temperature by combustion method in the initial stage. In order to ignite the gasoline and air mixture stably, the glow plug is installed after ATR catalyst. When the catalyst is increased to light-off temperature, the reformer is operated from initiation to steady state conditions as follows: Partial oxidation(POX) mode, partial ATR mode, full ATR mode. Finally the start-up and control strategy is validated by the operational test of gasoline fuel processor at low and room temperature. As a result the gasoline fuel processor is able to start-up within 40 min and to produce the reformate gas which has 37 ~ 42 vol.%(dry basis) of $H_2$ and 0.3 vol.% of CO.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.70-73
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• 2002

Thin films of vanadium oxide($VO_{x}$) have been deposited by r.f. magnetron sputtering from $V_{2}O_{5}$ target in gas mixture of argon and oxygen. The oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% is adopted. Crystal structure, chemical composition, molecular structure and optical properties of films sputter-deposited under different oxygen gas pressures and in-situ annealed in vacuum at $400^{\circ}C$ for 1h and 4h are characterized through XRD. RBS, FTlR and optical absorption measurements. The films as-deposited are amorphous and those annealed for time longer than 4h are polycrystalline. $V_{2}O_{5}$ and lower oxides co-exist in sputter-deposited films and as the oxygen partial pressure is increased the films become more stoichiometric $V_{2}O_{5}$. When annealed at $400^{\circ}C$, the as-deposited films are reduced to a lower oxide. It is observed that the oxygen atoms located on the V-O plane of $V_{2}O_{5}$ layer participate more readily in the oxidation and reduction process. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly between 400 and 550nm.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.82-87
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• 2013

In this work, the 1L grade integrated metal DOC/DPF filter that can install in engine manifold position was developed to investigate the effect of platinum-coating amount of filter on the improvement of filter activation temperature and reduction of particulate matter (PM). This filter was installed in 2.9L CI engine which meets the EURO-4 emission regulation. Tests for PM reduction efficiency of filter were conducted under ND-13 mode with full-load test condition. It was revealed that the time to reach the activation temperature of metal filter ($280^{\circ}C$) was shorter as the amount of platinum-coating increased. This short activation time can be helpful for the reduction of CO and HC emissions during cold start condition. At the same time, PM reduced as the coating amount increased. The reduction percentage of $DOC_{40}$, $DOC_{20}$, and $DOC_0$ were 96.7% (2.34 mg/kW'h), 95.1% (3.47 mg/kW'h), and 94.5% (3.69 mg/kW'h) compared to previous result (71.4 mg/kW'h), respectively.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.567-573
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• 2008

This study investigated the effects of sodium chloride, potassium chloride, potassium lactate and calcium ascorbate on the physico-chemical and sensory characteristics of sodium-reduced pork patties. Pork patties were prepared in 4 ways: T1 (control, 1.0% NaCl), T2 (0.6% NaCl, 0.4% KCl), T3 (0.7% NaCl, 0.3% potassium lactate) and T4 (0.7% NaCl, 0.3% calcium ascorbate). The pH, cooking loss, total plate counts, TBARS (2-thiobarbituric acid reactive substances), surface color (L, a, b) and sensory characteristics were evaluated. The partial substitution of NaCl with KCl and calcium ascorbate decreased the cooking loss and TBARS values, and enhanced microbial stability. The partial substitution of NaCl with potassium lactate significantly decreased TBARS values and enhanced microbial stability, but significantly increased cooking loss compared to the control after 1 and 4 days of storage. However, the surface color and sensory characteristics were not affected by any of the treatments.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.922-929
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• 2007

The complete oxidation of ammonia to nitrate is a distinctive two-step process divided into the oxidation of ammonia to nitrite(nitritation) by Nitrosomonas and the oxidation of nitrite to nitrate(nitratation) by Nitrobacter. The nitrogen removal via nitrite accumulation offers several advantages such as saving costs for aeration, saving carbon source and finally reduction of sludge discharge. In this work a suspended bioreactor coupled with membrane filtration(MBR) was used to find the process conditions of nitrite build-up. The MBR enables to reach sufficient nitrifying bacteria in the bioreactor, although the autotrophic bacteria can be easily washed out due to their lower growth rate. The dissolved oxygen concentration $c'_{O2}$ and ammonia concentration $c_{NH3}$ in the reactor were varied and investigated as parameters for nitrite accumulation. As a result the higher ammonia concentration in the reactor is very effective for starting nitrite build-up and the effect was strengthened in combination with lower dissolved oxygen concentration. With lower $c'_{O2}<0.3$ $mgL^{-1}$ $O_2$ and high $c_{NH3}=6.3\sim14.9$ $mgL^{-1}$ $NH_3N$ the 74% of the nitrite accumulation was achieved. Specially, it was found that the nitrite accumulation could occur not only in biofilm reactor as many references showed but also in the membrane bioreactor carried out in this study.

• Transactions of the Korean hydrogen and new energy society
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• v.7 no.1
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• pp.45-54
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• 1996

Electrochemical oxidation of hydrogen on PdOx and Pd electrodes were investigated in aqueous 30% KOH solution at different temperatures and hydrogen concentrations(partial pressures). Anodic reaction by hydrogen on PdOx electrode was mainly due to the oxidation of adsorbed hydrogen at -0.8V~-0.5V(vs. Hg/HgO). For Pd electrode, the anodic reaction was participated by the adsorbed hydrogen on surface, as well as by the metal hydride formed from direct reaction between Pd and hydrogen at -0.5V~0.0V(vs. Hg/HgO). With the increase of hydrogen concentration the charge transfer resistance decreased and the exchange current increased. The transfer coefficient of PdOx and Pd electrodes were found to be 0.78 and 0.72 respectively, which shows the superior reactivity of Pd electrode. The activation energies of PdOx and Pd electrodes decreased with the increase of overpotential and were found to be 23.9~20.3 kJ/mole and 7.2~3.0kJ/mole, respectively.

• Korean Journal of Microbiology
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• v.43 no.2
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• pp.130-136
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• 2007

Natural 6-dodecen-4-olide (Butte lactone) was produced from plant oils containing high unsaturated fatty acids via two-stage microbial hiotransformation. After unsaturated fatty acids were liberated from plant oil by microbial lipase, these were converted to optically active hydroxyl fatty acid (HFA) by hydroxylation reaction of Pseudomonas sp. NRRLB-2994. When safflower oil containing >75% unsaturated fatty acid, linoleoic acid wasused, Pseudomonas sp. produced 8g/L of 10-hydroxy-12(z)-octadecanoicacid with average of 39.2% bioconversion efficiency during 48 hr biotransformation period. The recovered 10-hydroxy-12-octadecanoic acid was further bioconverted to 4-hydroxy-6-dodecenoic acid via partial ${\beta}-oxidation$ by Yarriowia lipolytica ATCC34088. 4-hydroxy-6-dodecenoic acid in culture was lactonized by lowering pH to 4.0 using $4N\;H_{2}SO_{4}$ and heating for 5 min to 6-dodecen-4-olide (Butter lactone). Natural 6-dodecen-4-olide had characteristic aroma properties when compared to 6-dodecan-4-oilde (dodecalactone) and 4-decen-4-olide (decalactone).

• Applied Chemistry for Engineering
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• v.2 no.2
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• pp.165-174
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• 1991

The kinetics and the mechanism for the selective oxidation of ethylene on the supported monolithic silver catalyst were experimentally investigated in a fixed bed tubular reactor. The formation rates of ethylene oxide and carbon dioxide were measured at the atmospheric pressure with various combinations of partial pressures of ethylene and oxygen at temperature range of $225-300^{\circ}C$, conversion with 1.2-7.5 %, and then the mechanism of the selective oxidation of ethylene was verified. Their formation rates fitted with the Langmuir-Hinshelwood mechnism. The ethylene oxide and carbon dioxide are produced by reation of adsorbed ethylene with monoatomic oxygen adsorbed on the active sites of Ag-surface, and their formation rate equation are expressed as : $R_{EO}={\frac{k_1K_0{^{1/2}}K_EK_SP_{02}{^{3/2}}P_E}{(1+{\sqrt{K_0P_{02}}}+K_EP_E+K_PP_P)^2(1+{\sqrt{K_SP_{02}})^2}}$ $R_C={\frac{k_2K_0{^3}K_EK_S{^{7/2}}P_{02}{^{13/2}}P_E}{(1+{\sqrt{K_0P_{02}}}+K_EP_E+K_PP_P)^7(1+{\sqrt{K_SP_{02}})^7}}$ The activation energies of ethylene oxide and dioxide and carbon dioxide formations can be estimated to be 12.25 and 17.85 Kcal/mol, respectively.

• Food Science and Preservation
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• v.21 no.5
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• pp.727-734
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• 2014

To investigate anti-thrombosis and anti-oxidation activities of the root of Arctium lappa L (RALL), which has been used as foodstuff and oriental medicine in Korea, the ethanol extract and its subsequent organic solvent fractions of the RALL were prepared. The yield of ethanol extraction was 10.94%, and the content of total polyphenol and total sugar of ethanol extract were 5.01 and 694.53 mg/g, respectively. The fraction yields of n-hexane, ethylacetate (EA), butanol and water residue were 1.62, 0.42, 5.98 and 85.38%, respectively. In anticoagulation activity assay, the ethanol extract of RALL did not show significant changes in thrombin time (TT), prothrombin time (PT) and activated partial thromboplastin time (aPTT), whereas the EA fractions showed 13 folds extended TT, PT, and aPTT respectively. Interestingly, the water residue showed strong activation effect against blood clotting factors with shortened aPTT, which might provide the evidence of coagulation agent of RALL in folk remedy. In anti-platelet aggregation assay, the activity of the ethanol extract and its fractions were comparable to that of aspirin. Especially the EA fraction showed 2-folds higher inhibitory activity than aspirin. In anti-oxidation activity assay, the EA fraction also showed strong in DPPH, ABTS and nitrite scavenging activity, and reducing power activity. The extract and fractions of RALL have ignorable hemolytic activity against human RBC up to 0.5 mg/mL concentration. Our results suggest that the EA fraction of RALL have potentials as safe and novel anti-thrombosis agent.

• Food Science and Preservation
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• v.24 no.5
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• pp.658-665
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• 2017

The current study was performed to investigate the changes of bio-activities of Salicornia europaea (SE) depending on the different dry methods. The ethanol extracts were prepared from the freeze-drying SE (FD), hot-air drying SE (HD), and shade drying SE (SD). Their anti-oxidant and anti-thrombosis activities were compared. The yields of ethanol extraction in FD, HD, and SD were 14.4, 13.2 and 11.9%, respectively. The highest contents of total polyphenol (4.6 mg/g) and total sugar (23.4 mg/g) were shown in FD, whereas, the highest content of reducing sugar (14.6 mg/g) was observed in HD. In anti-oxidation activity assay, the FD and HD showed similar radical scavenging activities and reducing power. However, in SD, nitrite scavenging activity and reducing power were severely decreased. In anti-coagulation activity assay, the thrombin time (TT), prothrombin time (PT) and activated partial thromboplastin time (aPTT) of FD, HD and SD did not show significant changes at 5 mg/mL concentration. But the HD at 7 mg/mL had strong inhibitions against thrombin and blood coagulation factors. The platelet aggregation and hemolysis activities were not affected by dry methods. Our results suggest that both FD and HD are effective to maintain the functional ingredient of SE, and HD is economic and efficient dry process for production of functional food.