• Membrane Journal
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• v.32 no.6
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• pp.427-441
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• 2022

Polymer electrolyte membrane (PEM) serving as a separator that can prevent the permeation of unreacted fuels as well as an electrolyte that selectively transports protons from the anode to the cathode has been considered a key component of polymer electrolyte membrane fuel cell (PEMFC). The perfluorinated sulfonic acid-based PEMs, represented by Nafion®, have been commercialized in PEMFC systems due to their high proton conductivity and chemical stability. Nevertheless, these PEMs have several inherent drawbacks including high manufacturing costs by the complex synthetic processes and environmental problems caused by producing the toxic gases. Although numerous studies are underway to address these drawbacks including the development of sulfonated hydrocarbon polymer-based PEMs (SHP-PEMs), which can easily control the polymer structures, further improvement of PEM performances and durability is necessary for practical PEMFC applications. Therefore, this study focused on the various strategies for the development of SHP-PEMs with outstanding performance and durability by 1) introducing cross-linked structures, 2) incorporating organic/inorganic composites, and 3) fabricating reinforced-composite membranes using porous substrates.

• Membrane Journal
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• v.32 no.6
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• pp.442-455
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• 2022

High-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) has been studied as an alternative to low-temperature PEMFC due to its fast activation of electrodes and high resistance to electrode poisoning by carbon monoxide. It is highly required to develop stable PEMs operating at high temperatures even doped by ion-conducting materials for the development of high-performance and durable HT-PEMFC systems. A number of studies have been conducted to develop polybenzimidazole (PBI)-based PEMs for applications in HT-PEMFC due to their high interaction with doped ion-conducting materials and outstanding thermomechanical stability under high-temperature operation. This review focused on the development of PBI-based PEMs showing high performance and durability. Firstly, the characteristic behavior of PBI-based PEMs doped with various ion-conducting materials including phosphoric acid was systematically investigated. And then, a comparison of the physicochemical properties of the PEMs according to the different membrane manufacturing processes was conducted. Secondly, the incorporation of porous polytetrafluoroethylene substrate and/or inorganic composites to PBI matrix to improve the membrane performances was studied. Finally, the construction of cross-linked structures into PBI-based PEM systems by polymer blending method was introduced to improve the PEM properties.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.228-236
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• 2008

Validation of viral safety is essential in ensuring the safety of mammalian cell culture-derived biopharmaceuticals, because numerous adventitious viruses have been contaminated during the manufacture of the products. Mammalian cells are highly susceptible to Reovirus type 3 (Reo-3), and there are several reports of Reo-3 contamination during the manufacture of biopharmaceuticals. In order to establish the validation system for the Reo-3 safety, a real-time RT-PCR method was developed for quantitative detection of Reo-3 in cell lines, raw materials, manufacturing processes, and final products as well as Reo-3 clearance validation. Specific primers for amplification of Reo-3 RNA was selected, and Reo-3 RNA was quantified by use of SYBR Green I. The sensitivity of the assay was calculated to be $3.2{\times}10^0\;TCID_{50}/ml$. The real-time RT-PCR method was proven to be reproducible and very specific to Reo-3. The established real-time RT-PCR assay was successfully applied to the validation of Chinese hamster ovary (CHO) cell artificially infected with Reo-3. Reo-3 RNA could be quantified in CHO cell as well as culture supernatant. When the real-time RT-PCR assay was applied to the validation of virus removal during a virus filtration process, the result was similar to that of virus infectivity assay. Therefore, it was concluded that this rapid, specific, sensitive, and robust assay could replace infectivity assay for detection and clearance validation of Reo-3.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.89.1-89.1
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• 2010

Since Gratzel and co-workers developed a new type of solar cell based on the nanocrystalline $TiO_2$ electrode, dye-sensitized solar cells (DSSCs) have attracted considerable attention on account of their high solar energy-to-conversion efficiencies (11%), their easy manufacturing process with low cost production compared to conventional p-n junction solar cells. The mechanism of DSSC is based on the injection of electrons from the photoexcited dye into the conduction band of nanocrystalline $TiO_2$. The oxidized dye is reduced by the hole injection process from either the hole counter or electrolyte. Thus, the electronic structures, such as HOMO, LUMO, and HOMO-LUMO gap, of dye molecule in DSSC are deeply related to the electron transfer by photoexcitation and redox potential. To date, high performance and good stability of DSSC based on Ru-dyes as a photosensitizer had been widely addressed in the literatures. DSSC with Ru-bipyridyl complexes (N3 and N719), and the black ruthenium dye have achieved power conversion efficiencies up to 11.2% and 10.4%, respectively. However, the Ru-dyes are facing the problem of manufacturing costs and environmental issues. In order to obtain even cheaper photosensitizers for DSSC, metal-free organic photosensitizers are strongly desired. Metal-free organic dyes offer superior molar extinction coefficients, low cost, and a diversity of molecular structures, compared to conventional Ru-dyes. Recently, novel photosensitizers such as coumarin, merocyanine, cyanine, indoline, hemicyanine, triphenylamine, dialkylaniline, bis(dimethylfluorenyl)-aminophenyl, phenothiazine, tetrahydroquinoline, and carbazole based dyes have achieved solar-to-electrical power conversion efficiencies up to 5-9%. On the other hand, organic dye molecules have large ${\pi}$-conjugated planner structures which would bring out strong molecular stacking in their solid-state and poor solubility in their media. It was well known that the molecular stacking of organic dyes could reduce the electron transfer pathway in opto-electronic devices, significantly. In this paper, we have studied on synthesis and characterization of dendritic organic dyes with different number of electron acceptor/anchoring moieties in the end of dendrimer. The photovoltaic performances and the incident photon-to-current (IPCE) of these dyes were measured to evaluate the effects of the dendritic strucuture on the open-circuit voltage and the short-circuit current.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.54-54
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• 2010

In this study, the correlation between temperature and the gel-content of the module were analyzed through experiments. Amorphous thin-film solar cell used in this experiment has a visible light transmission performance of 10%. In addition, ethylene vinyl acetate(EVA) film and the clear glass have been used for the modulation. The most important process is to laminate the module in the manufacturing process of BIPV(Building integrated photovoltaic) module. Setting parameters of laminator in the lamination process are temperature, pressure and time. Setting conditions significantly affect the durability, watertightness and airtightness of module. The most important factor in the setting parameters is temperature to satisfy the gel-contents. The bottom and top surface temperature of module are measured according to setting temperature of laminator. The results showed $145^{\circ}C$ of max temperature of the bottom surface and $128^{\circ}C$ of max temperature of top surface on the module at the temperature condition of $160^{\circ}C$. And at the another temperature condition of laminator with $150^{\circ}C$, the max temperature do bottom and top are $117^{\circ}C$ and $134^{\circ}C$ respectively. The temperature difference between bottom and top of the module occurred, that is because heat has been blocked by the clear glass and the bottom of the cells absorb the heat from the laminator. In this particular, the temperature difference between setting temperature of the laminator and the surface temperature of the module showed $15^{\circ}C$, because the heat of laminator plate is transferred to the surface of the module and heat is lost at this time. As a results, gel-content showed 94.8%, 88.7% and 81.7% respectively according to the setting temperature $155^{\circ}C$, $150^{\circ}C$ and $145^{\circ}C$ of the laminator. In conclusion, the surface temperature of module increases, the gel-contents is relatively increased. But if the laminator plate temperature is too high, the gel-content shows rather decline in performance. Furthermore, the temperature difference between setting temperature and the surface temperature of the module is affected by laminating machine itself and the temperature of module should be considered when setting the laminator.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.2
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• pp.114-118
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• 2001

In manufacturing process of Changran-Jeotgal, agitation with 10 rpm for 10 min/4 hrs of Changran-Jeotgal without released extract was carried out during the fermented process at $0\pm2^{\circ}C$ to shorten the fermentation period and uniform product quality, This step was called Improved process, while the step with release extract and standing fermentation was Conventional process. During 60 days of fermentation period, chemical, microbiological changes and sensory evaluation were examined, Brix, VBN and $NH_2-N$ were 27.4, $54.3\;mg\%\;and\;87.9 mg\%$ on 30th day in Improved process, respectively, but they were 27.1, $57.8\;mg\%\;and\;96.6\;mg\%$ on 50th day in Conventional process. The pH value was decreased from 7.0 to $\6.3\~6.5$ in both of them, The viable cell counts in Improved process was increased from $6.6\times10^3CFU/g\;to\;2.6\times10^6CFU/g$ during 30 days, in Conventional process, slowly increased from $5.8\times10^3CFU/g\;to\;1.9\times10^6CFU/g$ during 50 days. Sensory evaluation showed that products on 30th day in Improved process and products on 50th day in Conventional process were best favorable. From above results, we found that the fermentation with agitation shortened the fermentation period by 20 days compare to standing fermentation.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.117.2-117.2
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• 2011

Since Gratzel and co-workers developed a new type of solar cell based on the nanocrystalline TiO2 electrode, dye-sensitized solar cells (DSSCs) have attracted considerable attention on account of their high solar energy-to-conversion efficiencies (11%), their easy manufacturing process with low cost production compared to conventional p-n junction solar cells. The mechanism of DSSC is based on the injection of electrons from the photoexcited dye into the conduction band of nanocrystalline TiO2. The oxidized dye is reduced by the hole injection process from either the hole counter or electrolyte. Thus, the electronic structures, such as HOMO, LUMO, and HOMO-LUMO gap, of dye molecule in DSSC are deeply related to the electron transfer by photoexcitation and redox potential. To date, high performance and good stability of DSSC based on Ru-dyes as a photosensitizer had been widely addressed in the literatures. DSSC with Ru-bipyridyl complexes (N3 and N719), and the black ruthenium dye have achieved power conversion efficiencies up to 11.2% and 10.4%, respectively. However, the Ru-dyes are facing the problem of manufacturing costs and environmental issues. In order to obtain even cheaper photosensitizers for DSSC, metal-free organic photosensitizers are strongly desired. Metal-free organic dyes offer superior molar extinction coefficients, low cost, and a diversity of molecular structures, compared to conventional Ru-dyes. Recently, novel photosensitizers such as coumarin, merocyanine, cyanine, indoline, hemicyanine, triphenylamine, dialkylaniline, bis(dimethylfluorenyl)-aminophenyl, phenothiazine, tetrahydroquinoline, and carbazole based dyes have achieved solar-to-electrical power conversion efficiencies up to 5-9%. On the other hand, organic dye molecules have large ${\pi}$-conjugated planner structures which would bring out strong molecular stacking in their solid-state and poor solubility in their media. It was well known that the molecular stacking of organic dyes could reduce the electron transfer pathway in opto-electronic devices, significantly. In this paper, we have studied on synthesis and characterization of dendritic organic dyes with different number of electron acceptor/anchoring moieties in the end of dendrimer. The photovoltaic performances and the incident photon-to-current (IPCE) of these dyes were measured to evaluate the effects of the dendritic strucuture on the open-circuit voltage and the short-circuit current.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.386-390
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• 1993

Addition of starch syrup, table sugar, potato powder, skim milk powder an parched soybean powder to melon flesh was suitable as fermented melon base. The manufacturing process of fermented melon was as follows: Pasteurization for 10 min at $95^{\circ}C$, use of 1% starter culture, fermentation for 12 hours at $35^{\circ}C$ and ripening for 3 days at $8^{\circ}C$. The growth and acid production of Pediococcus acidilactici among several starter cultures were most active for the first 12 hours, but such activities were disappeared during ripening. In the case of Lactobacillus plantarum, the activities were not high during fermentation, which, however, increased during ripening. Throughout the whole manufacturing process, the fermented melon with a mixed culture of P. acidilactici and L. plantarum showed more cell number of each bacterium and higher titratable acidity than that with single cultures. Also P. acidilactici surpressed the growth of L. plantarum during ripening.

• Journal of Distribution Science
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• v.11 no.10
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• pp.17-25
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• 2013

Purpose - This study analyzes the effect of customers' perceived service innovativeness of service centers for electronic goods, on repurchase intentions of customers, using behavior intentions of service centers as a mediator variable. In customer management and customer relationship marketing, service centers can be the most representative customer relationship management departments because they are most closely placed at the interface with customers. In addition, this study intends to investigate if continuous relationship with customers during one-time product-selling can affect their repurchase intentions. Specifically, this research aims to investigate if the expansion of the saturated physical market of the manufacturing business, to intangible service markets, can be competitive enough to satisfy customer needs. Research design, data, and methodology - This study targets college students, and especially those who have computers, digital cameras, or cell-phones, and often use electronic products and services. In order to investigate our hypothesis, we analyzed dates through SEM (structural equation modeling) using SPSS for Windows 18.0 and AMOS 18.0. In addition, we measured Cronbach's α coefficient using SPSS for Windows 18.0 in order to measure reliability. Further, using AMOS 18.0, this research statistically measured convergent validity as well as discriminant validity, and examined mediation models and path models in which service innovativeness leads to customers' repurchase intentions of electronic products. Results - As a result, this research shows that customers' perceived service innovativeness of service centers for electronic goods has significant positive influence on customers' behavior intentions of service centers. In addition, service innovativeness of electronic goods' service centers also has significant positive influence on repurchase intentions of customers. Conclusion - This study investigates the effect of customers' positive relation with the innovativeness of electronic service center on their behavior intention and product repurchase. The more concrete, important results of the study are as follows. Through the mediating effect, the findings of the study suggest that customers' behavior intentions of service centers partially mediate the effect of customers'perceived service innovativeness of service centers for electronic goods on customers' repurchase intentions. This research also provides an insight that the importance of service innovativeness and innovative approaches in managing customers should be recognized in the process of repurchase and service roles of manufacturing business as a way for customer management. As a result, the relationship between customer satisfaction and service quality of service centers for the electronic products is very sensitive. Although previous studies focus on certain aspects of the case for enhancing service innovation (Kim, 2012), this research recommends that the service centers need to understand the customers'desire first and try to adapt to achieve customer satisfaction by being innovative. This innovativeness of service centers would make customers visit them consistently, which in the long run, will also influence their repurchase decisions.

• Journal of Life Science
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• v.25 no.2
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• pp.206-213
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• 2015

Sunsik has been popular as well-being and healthy food to some Asian people, but it still has a limit to other foreigners because of its taste and appearance. This study tried to modify Sunsik into smoothie type for foreigners and investigate its physicochemical characteristics. Germinated black and brown rice was prepared. The germination condition of two cereals was steeping for 24 hr at room temperature, and then germinating for 24 hr at $30^{\circ}C$. After germination, the ${\alpha}$-amylase activity of germinated grains was 13~15 times higher than before germination. The enzyme activity of brown rice was 9.16 CU/g, but germinated brown rice was 152.63 CU/g. In case of black rice, enzyme activity before germination was 7.47 CU/g, and enzyme activity after germination was 97.96 CU/g. The lactic acid bacteria was grown in 50 g germinated brown rice powder with 100 ml malt solution, 30 g tomato juice, and 1.5 g rice bran. After manufacturing beverage using milk and Sunsik and the cell count of lactic acid bacteria was $1.3{\times}10^5CFU/ml$ enough to use starter. According to sensory test, the optimal concentration of Sunsik smoothie was 30 g Sunsik in 200 ml of milk. The viscosity was $5.97{\pm}1.2$ centipoise. The color of Sunsik beverage was evaluated as L value : $63.50{\pm}0.41$, a value: $-0.35{\pm}0.06$, and b value: $8.85{\pm}0.19$.