• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.491-496
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• 2017

The hydrogen($H_2$) is promising energy carrier of renewable energy in the microgrid system such as small village and military base due to its high energy density, pure emission and convenient transportation. $H_2$ can be generated by photocatalytic water splitting, gasification of biomass and water electrolysis driven by solar cell or wind turbine. Solid oxide electrolysis cells(SOECs) are the most efficient way to mass production due to high operating temperature improving the electrode kinetics and reducing the electrolyte resistance. The SOECs are consist of nickel-yttria stabilized zirconia(NiO-YSZ) fuel electrode / YSZ electrolyte / lanthanum strontium manganite-YSZ(LSM-YSZ) air electrode due to similarity to Solid Oxide Fuel Cells(SOFCs). The Ni-YSZ most widely used fuel electrode shows several problems at SOEC mode such as degradation of the fuel electrode because of Ni particle's redox reaction and agglomeration. Therefore Ni-YSZ need to be replaced to an alternative fuel electrode material. In this study, We studied on the Double perovskite $PrBrMnO_{5+{\delta}}$(PBMO) due to its high electric conductivity, catalytic activity and electrochemical stability. PBMO was impregnated into the scaffold electrolyte $La_{0.8}Sr_{0.2}Ga_{0.85}Mg_{0.15}O_{3-{\delta}}$(LSGM) to be synthesized at low temperature for avoiding secondary phase generated when it exposed to high temperature. The Half cell test was conducted at SOECs and SOFCs modes.

• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1203-1207
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• 2018

In this study, silica nanowires were formed using silicon oxide films with different oxygen contents, and their microstructure and physical properties were compared with those of silica nanowires formed using Si wafers. The silicon oxide films were fabricated by using a plasma-enhanced chemical vapor deposition method. Silica nanowires were formed by thermally annealing silicon oxide films coated with nickel films as a catalyst. In the case of silicon oxide films having an oxygen content of approximately 50 at.% or less, the formation mechanism, microstructure, and physical properties of the nanowires were not substantially different from those of the silicon wafer. In particular, the uniformity of the thickness showed better behavior in the silicon oxide films. These results imply that silicon oxide films can be used as an alternative for fabricating high-quality silica nanowires at low cost.

• Membrane Journal
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• v.31 no.6
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• pp.393-403
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• 2021

Enzymes are important class of catalyst for biotransformation. Stability and reusability of enzymes during the catalysis process is a key issue. Activity of enzyme can be enhanced by its immobilization on a suitable substrate by creation of specific microenvironment. A variety of membranes has been used as substrate due to the biocompatibility and simpler method to tune hydrophilicity/hydrophobicity property of the membrane surface. In this review, polymer membranes including cellulose, polyacrylonitrile (PAN), polydimethylsiloxane (PDMS), polyvinylidene fluoride (PVDF), polyethersulfone (PES) are introduced and discussed in detail. Biodegradation of organic contaminants by immobilized enzyme is an environmental friendly process to reduce the contamination of environment in pharmaceutical company and textile industries. The controlled hydrolysis of oil can be performed in enzyme immobilized membrane bioreactor (EMBR), resulting in reducing carbon emission and reduced environmental pollution. Bioethanol and biodiesel are considered alternative fossil fuels that can be prepared in EMBR.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.226-233
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• 2023

To create an environmentally sustainable fuel with a low sulfur concentration, requires alternative sulfur removal methods. During the course of this study, a high surface gamma alumina-supported ZnO nanocatalyst with a ZnO/-Al₂O₃ ratio of 12% was developed and tested for its ability to improve the activity of the oxidative desulfurization (ODS) process for the desulfurization of kerosene fuel. Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) were used to characterize the produced nanocatalyst. In a digital batch baffled reactor (20~80 min), the effectiveness of the synthesized nanocatalyst was tested at different initial concentrations of dibenzothiophene (DBT) of 300~600 ppm, oxidation temperatures (25~70 ℃), and oxidation periods (0.5, 1, and 2 hours). The baffles included in the digital baffled batch reactor resist the swirling of the reaction mixture, thus facilitating mixing. The ODS procedure yielded the maximum DBT conversion (95.5%) at 70 ℃ with an 80-minute reaction time and an initial DBT level of 600 ppm. The most precise values of kinetic variables were subsequently determined using a mathematical modelling procedure for the ODS procedure. The average absolute error of the simulation findings was less than 5%, demonstrating a good degree of agreement with the experimental results acquired from all runs. The optimization of the operating conditions revealed that 99.1% of the DBT can be removed in 140 minutes.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.1 no.1
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• pp.23-52
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• 2006

Industry-academy Collaboration alms to produce synergy-empowerment through co-opt between university and business within R&D and human resource management. The lack of indigenous R&D capabilities makes Korean small businesses not have sustainable competitive advantages. While the Korean government has increased the budgetary supports on small businesses since the late 1990s to enhance technological capabilities of small businesses, the competitiveness gap between large and small firms has been widened. The alternative for the government support is considered as active industry-academy collaboration. After exploring various policy measures for the collaboration with classifying them and pointing out their problems from a technological innovation perspective, this study shows the more expected roles of the collaboration to be a catalyst coordinating the R&D activities among the local small businesses, local universities, and public research institutes. Based upon the analyses, this study suggests several policy alternatives to facilitate the technological innovations of small businesses in the regional innovation clusters.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.574-581
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• 2008

The optimum regeneration conditions for the regeneration of three way spent catalysts (TWCs), which were taken from automobiles with different driving conditions, were investigated to evaluate the suitability as alternative catalysts for removing VOCs. The spent catalysts were washed with five different acids ($HNO_3$, $H_2SO_4$, $C_2H_2O_4$, $C_6H_8O_7$, and $H_3PO_4$) to remove contaminants and examine the optimum conditions for recovering the catalytic activity. The physicochemical properties of spent and its regenerated TWCs were evaluated by using nitrogen adsorption-desorption isotherms, XRD, and ICP. The relative atomic ratios of contaminants and platinum group metals (PGMs) of the spent TWCs were greatly dependent on the placed positions. The main contaminants formed were lubricant oil additives and metallic components. Also, the regeneration treatment increased the PGMs ratio, BET surface area, and average pore diameter of TWCs. The catalytic activity results indicated that the spent TWCs have the possibility for removing VOCs. Moreover, the employed acid treatments greatly enhanced the catalytic activity of the spent TWCs. Especially, nitric and oxalic acids provided the most improvement in the catalytic behavior. The catalytic activities of the regenerated TWCs were significantly influenced by the containing platinum ratios rather than the removal ratios of contaminants and the changes in the structural properties offered by the acid treatments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5728-5735
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• 2015

This study attempts to verify the applicability of ceramic membrane as a separator by comparing the power generation characteristics in single-chamber MFCs using ceramic membranes to those in the MFCs using nafion membrane. The generated power in MFCs by using acetate as a substrate was more stable than that by using formate, propionate and butyrate, respectively. It was shown that the generated power by using formate substrate in MFCs was unstable and a little higher than that by using acetate, and the power generated by using propionate and butyrate were lower than that by using acetate. In order to find out the Pt catalyst effect, it was compared the power generated in MFCs using Pt-coated carbon cloth as electrode to that power using normal carbon cloth. The power generated in MFCs using Pt-coated carbon cloth as electrode was 1.2 times higher than that using normal carbon cloth. The Pt-coated carbon cloth was about 5 times more expensive than normal carbon cloth. It is suggested that both power generation efficiency and cost together should be considered in selecting electrodes of MFCs. It was found that the ceramic membrane was superior to nafion membrane by comparing to the power generation characteristics obtained. It was shown that average voltage values were $523.67mV{\pm}49.41mV$ by using synthetic wastewater, in MFCs of ceramic membrane as a separator. While average voltage values were $424.09mV{\pm}79.95mV$ by using synthetic wastewater, in MFCs of nafion membrane as a separator. The organic removal efficiency, 41.7% by using ceramic membrane was a little bit higher than 40.8% by using nafion membrane. This research implies ceramic membrane can be a valid alternative to nafion membrane as a separator when considering the power generation and the efficiency of organics removal.

• Journal of the Korean Magnetics Society
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• v.24 no.6
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• pp.197-201
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• 2014

As the importance of rare metal is increasing globally, Japan introduced the concept of Strategic Elements in 2004, and started Strategic Elements Project in 2007. The Goal of this project run by MEXT (Ministry of Education, Culture, Sports, Science and Technology) is to develop high-function materials and components that do not use rare or harmful elements by studying the role and characteristics of the elements that compose materials and components and decide their functions and characteristics. In September 2010, Japanese coast guard arrested a Chinese fishing boat near Senkaku Islands (Diaoyudao Islands by China), which escalated to the territory issue and eventually a big diplomatic and economic conflict. In order to put pressure on Japanese Government, China used an economic option, which is the ban of rare earth export to Japan. This incident doubled Japan's motivation to develop Strategic Elements and put more efforts into this Project. MEXT set the following three research areas in February 2012: Study of alternative materials using sufficient and harmless elements, Study of applications for the high-functions of Strategic Elements, Study of practical design for components using Strategic Elements. Through a course of gathering the opinion of professionals, MEXT settled down with the following 4 research and study areas for the Strategic Elements Project in June 2012. 1. Magnetic materials to replace Dy, Nd. 2. Catalyst/Battery materials to replace Pt, Rh/Li, Co. 3. Electronic materials to replace In, Ta. 4. Structural materials to replace Nb, Mo. This paper deals with the first area and reviews the results of the research and study as of now.

• Clean Technology
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• v.11 no.4
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• pp.195-204
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• 2005

A new condensation process for manufacturing N-acyl taurates which generates less pollutant and produces more than 60 % yield in comparison with the conventional process has been developed in this work. Its optimum process conditions are at $210{\sim}230^{\circ}C$ of reaction temperature and 6 ~ 9 hour of reaction time when Parasol 123 of petroleum refired oil is employed as process solvent and mixed catalysts of sulfonic acid and phosphoric acid are utilized as process catalyst. And the qualities of N-acyl taurates produced by this new process are similar to or better than those of imported product judging from their acid value, amine value and color. Thus, it can be said that the newly developed process for manufacturing N-acyl taurates in this work is better than the conventional process. The physical properties of N-acyl taurates produced in this work such as surface tension, foaming power, foaming stability, hard water stability, and emulsifying power etc. were compared with those of commercially available anionic surfactants. And the experimental results show that N-acyl taurates shows good physical properties and that they can be alternative to conventional anionic surfactants.

• Clean Technology
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• v.26 no.2
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• pp.131-136
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• 2020

Biomass bamboo charcoal is utilized as anode for lithium-ion battery in an effort to find an alternative to conventional resources such as cokes and petroleum pitches. The amorphous phase of the bamboo charcoal is partially converted to graphite through a low temperature graphitization process with iron oxide nanoparticle catalyst impregnated into the bamboo charcoal. An optimum catalysis amount for the graphitization is determined based on the characterization results of TEM, Raman spectroscopy, and XRD. It is found that the graphitization occurs surrounding the surface of the catalysis, and large pores are formed after the removal of the catalysis. The formation of the large pores increases the pore volume and, as a result, reduces the surface area of the graphitized bamboo charcoal. The partial graphitization of the pristine bamboo charcoal improves the discharge capacity and coulombic efficiency compared to the pristine counterpart. However, the discharge capacity of the graphitized charcoal at elevated current density is decreased due to the reduced surface area. These results indicate that the size of the catalysis formed in in-situ graphitization is a critical parameter to determine the battery performance and thus should be tuned as small as one of the pristine charcoal to retain the surface area and eventually improve the discharge capacity at high current density.