• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.479-486
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• 2023

In this study, we investigated the effect of the Ce_xZr_1-xO₂ (CZ) addition onto Ni/Al₂O₃ catalysts on the catalytic performance in methane steam reforming. In the reaction results, the CZ-added Ni/Al₂O₃ catalyst showed higher CH₄ conversion and H₂ yield under the same reaction conditions than Ni/Al₂O₃. From the characterization data, the two catalysts had similar support porosity and Ni dispersion, confirming that the two properties could not determine the catalytic performance. However, the oxygen vacancy over the CZ-added Ni/Al₂O₃ catalyst induced an efficient steam activation at low reaction temperatures, resulting in an increase in the catalytic activity and H₂ yield.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.200-210
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• 2015

The modeling for fast pyrolysis of biomass in fluidized bed reactor has been developed for accurate prediction of bio-oil and gas products and for yield improvement. The purpose of this study is to analyze and to compare the CFD(Computational Fluid Dynamics) simulation results with the experimental data from the CFD simulation results with the experimental data from the reference(Mellin et al., 2014) for gas products generated during fast pyrolysis of biomass in fluidized bed reactor. CFD(ANSYS FLUENT v.15.0) was used for the simulation. Complex pyrolysis reaction scheme of biomass subcomponents was applied for the simulation of pyrolysis reaction. This pyrolysis reaction scheme was included reaction of cellulose, hemicellulose, lignin in detail, gas products obtained from pyrolysis were mainly $CO_2$, CO, $CH_4$, $H_2$, $C_2H_4$. The deviation between the simulation results from this study and experimental data from the reference was calculated about 3.7%p, 4.6%p, 3.9%p for $CH_4$, $H_2$, $C_2H_4$ respectively, whereas 9.6%p and 6.7%p for $CO_2$ and CO which are relatively high. Through this study, it is possible to predict gas products accurately by using CFD simulation approach. Moreover, this modeling approach should be developed to predict fluidized bed reactor performance and other gas product yields.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.57-65
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• 2000

Objective of research is obtain fundamental data of carbonized wood wastes for soil condition, de-ordorization, absorption of water, carrier for microbial activity, and purifying agent for water quality of river. The carbonization technique and the properties of carbonized wood wastes(wood-based materials) were analyzed. Proximate analysis showed the wood-based materials contains 0.37~2.27% ash, 70~74% volatile matter, and 17~20% fixed carbon. As carbonization temperature was increased, the charcoal yield was decreased. However, no difference in charcoal yield was found due to time increase. The specific gravity after the carbonization decreased about 30~40% comparing to green wood. The charcoal had 1.08~4.18% ash, 5.88~13.79% volatile matter, and 80.15~90.94% fixed carbon. The pH of plywood and particleboard(pH 9 at $400^{\circ}C$, pH 10 at $600^{\circ}C$ and $800^{\circ}C$) made charcoals was higher than that of fiberboard. The water-retention capacity was not affected by the carbonization temperature and time. The water-retention capacity within 24h was about 2~2.5 times of sample weight, and the Equilibrium moisture content(EMC) became 2~10% after 24h. EMC of charcoal from the thinned trees were 9.40~11.82%($20^{\circ}C$, RH 90%), 6.87~7.61%($20^{\circ}C$, RH 65%), and 1.69~2.81%($20^{\circ}C$, RH 25%). EMC of charcoal from the wood-based materials under $20^{\circ}C$, relative humidity(RH) 90% was similar to EMC of charcoal from the thinned trees(9~11 %). However, under $20^{\circ}C$, RH 25.65%, EMC of charcoal from the wood-based materials were higher(2~3%) than EMC of charcoal from the thinned trees. Every charcoal from the wood-based materials fulfilled the criteria in JWWA K 113-1947.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.378-384
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• 2018

$C_9H_7NHCrO_3Cl$ was synthesized by reacting $C_9H_7NH$ with chromium (VI) trioxide. The structure of the product was characterized by FT-IR (Fourier transform infrared) spectroscopy and elemental analysis. The oxidation of benzyl alcohol by $C_9H_7NHCrO_3Cl$ in various solvents showed that the reactivity increased with increasing dielectric constant(${\varepsilon}$) in the following order: DMF (N,N'-dimethylformamide) > acetone > chloroform > cyclohexane. The oxidation of alcohols was examined by $C_9H_7NHCrO_3Cl$ in DMF. As a result, $C_9H_7NHCrO_3Cl$ was found to be an efficient oxidizing agent that converts benzyl alcohol, allyl alcohol, primary alcohols, and secondary alcohols to the corresponding aldehydes or ketones (75%-95%). The selective oxidation of alcohols was also examined by $C_9H_7NHCrO_3Cl$ in DMF. $C_9H_7NHCrO_3Cl$ was the selective oxidizing agent of benzyl, allyl and primary alcohol in the presence of secondary ones. In the presence of DMF with an acidic catalyst, such as $H_2SO_4$, $C_9H_7NHCrO_3Cl$ oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, and $m-NO_2$). Electron donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. The Hammett reaction constant (${\rho}$) was -0.69 (308K). The observed experimental data were used to rationalize hydride ion transfer in the rate-determining step.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.4
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• pp.326-334
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• 2007

Purpose: The estrogen receptor (ER), which is over-expressed in ER-positive breast tumors, has been imaged by positron emission tomography (PET) using $[^{18}F]$ labeled estrogen ligands, especially $[^{18}F]FES$. However, $[^{18}F]$ has relatively short-lived half-life ($t_{1/2}$ =1.8 h) and the labeling yield of radio-fluorination is usually low compared with $^{64}Cu\;(t_{1/2}=12.7\;h)$. 1,4,7,10-tetraazacyclododecane (cyclen) is used to form stable metal complexes with copper, indium, gallium, and gadolinium. With these in mind, we prepared cyclen-based Cu complexes which mimic estradiol in aspect of two hydroxyl groups. Materials and Methods: 1.7-Protected cyclen, 1.7-bis (benzyloxycarbonyl)-cyclen was synthesized according to the reported procedure. After introducing two 4-benzyloxybenzyl groups at 4,10-positions, the benzyloxycarbonyl and benzyl groups were removed at the same time by hydrogenation on Pd/C to give 1,7-bis(4-hydroxybenzyl)-1,4,7,10-tetraazacyclododecane (1). Results: The prepared ligand 1 was fully characterized by $^1H,\;^{13}C$ NMR, and mass spectrometer. The synthesized ligand was reacted with copper chloride and copper perchlorate to give copper complexes $[Cu(1)]^{2+}2(CIO_4^-)\;and\;[Cu(1)Cl]^+Cl^-$ which were confirmed by high-resolution mass (FAB). Conclusion: We successfully synthesized a cyclen derivative of which two phenol groups are located on trans position of N-atoms. And, two Cu(ll) complexes of +2 and +1 overall charge, were prepared as a potential PET tracers for ER imaging.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.258-267
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• 2013

This study was conducted to determine the antioxidative and neuroprotective effect of pig skin extracts (PS) and pig skin gelatin hydrolysates (LPS) using a human neuroblastoma cell line (SH-SY5Y). The extraction yield of PS was 3 fold higher than that of LPS. The protein content of PS was about 10 fold higher than that of LPS (p<0.05). Also LPS increased antioxidative activity dose dependently, and the activity was significantly higher than PS at all concentration (p<0.05). DPPH radical scavenging activity of LPS at 50 mg/mL was 92.97%, which was similar to $1{\mu}M$ vitamin C as a positive control. ABTS radical scavenging activity of LPS (20 mg/mL) was 89.83% and oxygen radical absorbance capacity of LPS at 1 mg/mL was $141.39{\mu}M$ Trolox Equvalent/g. No significant change of human neuroblastoma cells was determined by MTT test. Cell death by oxidative stress induced by $H_2O_2$ and amyloid beta 1-42 ($A{\beta}_{1-42}$) was protected by LPS rather than PS. Acetylcholine esterase was significantly inhibited, by up to 33.62% by LPS at 10 mg/mL. Therefore, these results suggest that pig skin gelatin hydrolysates below 3 kDa have potential to be used as anti-oxidative and neuroprotective functional additives in the food industry, while further animal test should be determined in the future.