• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.116-120
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• 2015

Synthesis of butenes through dehydration of 2-butanol was investigated over HY zeolite catalysts. 2-Butanol dehydration reaction was carried out in a fixed bed catalytic reactor. 2-Butanol conversion was increased with increase of $Si/Al_2$ ratio of HY zeolite catalysts, which can be ascribed to increase of acid strength with increase of $Si/Al_2$ ratio. Selectivities to 1-butene, trans-2-butene, and cis-2-butene were not greatly influenced by the change of the $Si/Al_2$ ratio of HY zeolite. As a result, it was advantageous to use a HY zeolite catalyst with 60 $Si/Al_2$ ratio for maximizing the yield of 1-butene in the dehydration of 2-butanol. The optimal reaction temperature for maximizing the yield of 1-butene was $250^{\circ}C$ over HY (60) catalyst.

• Journal of Hydrogen and New Energy
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• v.16 no.2
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• pp.103-110
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• 2005

Proton conducting solid polymer electrolyte (SPE) membranes have been used in many energy technological applications such as water electolysis, fuel cells, redox-flow battery, and other electrochemical devices. The availability of stable membranes with good electrochemical characteristics as proton conductivity at high temperatures above 80 $^{\circ}C$ and low cost are very important for its applications. However, the presently available perfluorinated ionomers are not applicable because of high manufacturing cost and high temperature use to the decrease in the proton conductivity and mechanical strength. In order to make up for the weak points, the block copolymer (BPSf) of polysulfone and poly (phenylene sulfide sulfone) were synthesized and sulfonated. The electrolyte membranes were prepared with phosphotungstic acid (HPA)/sulfonated BPSf via solution blending. This study would be desirable to investigate the interaction between the HPA and sulfonated polysulfone. The results showed that the characteristics of SPSf/HPA blend membrane was a better than Nafion at high temperature, 100 $^{\circ}C$. These membranes proved to have a high proton conductivity, $6.29{\times}10-2$ S/cm, a water content, 23.9%, and a ion exchange capacity, 1.97 meq./g dry membrane. Moreover, some of the membranes kept their high thermal and mechanical stability.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.227-231
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• 2005

We have developed a microsystem with a capillary electrophoresis (CE) and an electrochemical detector (ECD). The microfabricated CE-ECD systems are adequate for a disposable type and the characteristics are optimized for an application to the electrochemical detection. The system was realized with polydimethylsiloxane (PDMS)-glass chip and indium tin oxide electrode. The injection and separation channels (80 um wide$\ast$40 um deep) were produced by moulding a PDMS against a microfabricated master with relatively simple and inexpensive methods. A CE-ECD systems were fabricated on the same substrate with the same fabrication procedure. The surface of PDMS layer and ITO-coated glass layer was treated with UV-Ozone to improve bonding strength and to enhance the effect of electroosmotic flow. For comparing the performance of the ITO electrodes with the gold electrodes, gold electrode microchip was fabricated with the same dimension. The running buffer was prepared by 10 mM 2-(N-morpholino)ethanesulfonic acid (MES) titrated to PH 6.5 using 0.1 N NaOH. We measured olectropherograms for the testing analytes consisted of catechol and dopamine with the different concentrations of 1 mM and 0.1 mM, respectively. The measured current peaks of dopamine and catechol are proportional to their concentrations. For comparing the performance of the ITO electrodes with the gold electrodes, electropherograms was measured for CE-ECD device with gold electrodes under the same conditions. Except for the base current level, the performances including sensitivity, stability, and resolution of CE-ECD microchip with ITO electrode are almost the same compared with gold electrode CE-ECD device. The disposable CE/ECD system showed similar results with the previously reported expensive system in the limit of detection and peak skew. When we are using disposable microchips, it is possible to avoid polishing electrode and reconditioning.

• Journal of the Korea Concrete Institute
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• v.26 no.5
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• pp.607-614
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• 2014

The purpose of this dissertation was to investigate the effect of mineral admixtures, such as fly ash, blast furnace slag powder, meta kaolin and silica fume, on the basic properties and durability of crushed sand shotcrete, selecting a series of shotcrete mixtures with a variable admixture. Compressive strength increased as the content of mineral admixtures increased, specially it was the most effective when using meta kaolin both at sample specimen and core after shotcreting. Rapid chloride ion permeability test and sulfuric acid resistance test showed that both durability increased as the substitute rate of mineral admixture increased. In air void analysis with image analysis, the targeted the spacing factor and specific surface were not satisfied because air-entrained agent was not used.

• Journal of Environmental Science International
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• v.22 no.8
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• pp.1009-1017
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• 2013

Perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS) is a new persistent organic pollutants of substantial environmental concern. This study investigated the potential of magnetic ion exchange resin (MIEX$^{(R)}$) as the adsorbent for the removal of PFOA and PFOS from Nakdong River water. In our batch experiments, we studied the effect of some parameters (pH, temperature, sulfate concentration) on the removal of PFOA and PFOS. The results of sorption kinetics on MIEX$^{(R)}$ show that it takes 90 min to reach equilibrium but the economical contact time and dosage were 30 min and 10 mL/L. An increase in pH (pH 6~10) leads to a decrease in PFOA (2.0%) and PFOS (3.6%) sorption on MIEX$^{(R)}$. The sorption of both PFOA and PFOS decreases with an increase in ionic strength for sulfate ion (${SO_4}^{2-}$), due to the competition phenomenon. An increase in water temperature ($8^{\circ}C{\sim}28^{\circ}C$) in water leads to a increase in PFOA (2.8%) and PFOS (4.3%) sorption on MIEX$^{(R)}$. Based on the sorption behaviors and characteristics of the adsorbents and adsorbates, ion exchange and hydrophobic interaction were deduced to be involved in the sorption, and hemi-micelles possibly formed in the intraparticle pores.

• Journal of the Korean Electrochemical Society
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• v.4 no.2
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• pp.41-46
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• 2001

The effect of organic additives such as PEG ind MPS on throwing power have been studied in the fabrication of porous reticular metal by electrodeposition using the mixture of cupric sulfate and sulfuric acid as electrolyte. Both the polarization test and the electrodeposition on the stacked electrodes, mean pore diameter of which was $250{\mu}m$, were performed to illustrate the behavior of throwing power quantitatively. As far as PEG was concerned, it lowered throwing power of electrodeposition on the porous electrode used in this work while the addition of MPS up to 500 ppm in electrolyte enhanced throwing power monotonously. When both MPS and PEG were added in electrolyte, the effect of MPS on throwing power was superior to that of PEG. However, the excess addition of MPS was found to cause the defect in mechanical strength of deposit layer. From the result of SEM observation, it could be concluded that less than 50 ppm of MPS in electrolyte was appropriate to avoid the breakage of deposit layer.

• BMB Reports
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• v.53 no.3
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• pp.154-159
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• 2020

We investigated the effects of physalin A, B, D, and F on osteoclastogenesis induced by receptor activator of nuclear factor κB ligand (RANKL). The biological functions of different physalins were first predicted using an in silico bioinformatic tool (BATMAN-TCM). Afterwards, we tested cell viability and cell apoptosis rate to analyze the cytotoxicity of different physalins. We analyzed the inhibitory effects of physalins on RANKL-induced osteoclastogenesis from mouse bone-marrow macrophages (BMMs) using a tartrate-resistant acid phosphatase (TRAP) stain. We found that physalin D has the best selectivity index (SI) among all analyzed physalins. We then confirmed the inhibitory effects of physalin D on osteoclast maturation and function by immunostaining of F-actin and a pit-formation assay. On the molecular level, physalin D attenuated RANKL-evoked intracellular calcium ([Ca(2+)](i)) oscillation by inhibiting phosphorylation of phospholipase Cγ2 (PLCγ2) and thus blocked the downstream activation of Ca2+/calmodulin-dependent protein kinases (CaMK)IV and cAMP-responsive element-binding protein (CREB). An animal study showed that physalin D treatment rescues bone microarchitecture, prevents bone loss, and restores bone strength in a model of rapid bone loss induced by soluble RANKL. Taken together, these results suggest that physalin D inhibits RANKL-induced osteoclastogenesis and bone loss via suppressing the PLCγ2-CaMK-CREB pathway.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.3
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• pp.208-212
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• 1987

In order to enrich the nutritional value of instant noodle and diverse utilization of Alaska pollack meat paste(AMP), several quality parameters of instant noodle mixed with AMP as enrichment of protein were investigated. Protein and amino acid contents of instant noodle were increased to $4.7\%\;and\;4,\;006.1mg\%$ by incremental level up to $30\%$ of AMP. Hardness, cooking weight and volume of noodle were also increased by the increments of AMP added, but tensile strength and soup turbidity were decreased. Sensory scores in flavor, color and soup taste of instant noodle mixed with AMP were revealed higher than that of without AMP, but texture scores were decreased with the increase of the AMP over $20\%$.

• Journal of Plant Biotechnology
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• v.5 no.4
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• pp.221-224
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• 2003

Leaf explants of Ixeris sonchifolia produced adventitious shoots at a frequency of 100% when cultured on MS medium supplemented with combinations of various concentrations of 6-benzyladenine (BA) (0.44, 4.44, or 8.87 ${\mu}M$) and 0.54 ${\mu}M$ NAA, or MS medium supplemented with 22.19 ${\mu}M$ BA and 2.69 ${\mu}M\;\alpha$-naphthaleneacetic acid (NAA) after four weeks of culture. Each explants (approximately $3{\times}6mm$) produced greater than 70 shoots at a combination of 0.44 ${\mu}M$ BA and 0.54 ${\mu}M$ NAA. Leaf explants produced shoots at a frequency of greater than 80% even at as low as 0.13 ${\mu}M$ BA as the sole growth regulator. Upon transfer to one-third strength MS with 0.54 ${\mu}M$ NAA, excised adventitious shoots were rooted at a frequency of 100%. Regenerated plantlets were transplanted to potting soil and grown to maturity in a greenhouse. The competence of I. sonchifolia for plant regeneration via organogenesis appears to be greater than the competence of tobacco, currently the best model plant for organogenesis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.603-612
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• 2000

Corrosion characteristics on the 12Cr alloy steel of turbine blade was electro-chemically investigated in 3.5wt% NaCI and 12.7wt% Na2S04 solution, respectively. Electro-chemical polarization test, Huey test and Oxalic acid etching test were previously conducted to estimate corrosion susceptibility of the material. And, using the horizontal corrosion fatigue tester, corrosion fatigue characteristics of 12Cr alloy steel in distilled water, 3.5wt% NaCI solution, and 12.7wt%(1M) Na2S04 solution were also fracture-mechanically estimated and compared their results. Parameter considered was room temperature, 60'C and 90'C. Corrosion fatigue crack length was measured by DC potential difference method.Obtained results are as follows,1) 12Cr alloy steel showed high corrosion rate in 3.5wt% NaCI solution and Na2S04 solution at high tempratue.2) Intergranular corrosion sensitivity of 12 Cr alloy was smaller than austenitic stainless steel.3) Corrosion fatigue crack growth rate in 3.5wt% NaCI and 12.7wt%(IM) Na2S04 solution is entirely higher than in the distilled water, and also increased with the temperature increase.