• Ceramist
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• v.23 no.2
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• pp.132-144
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• 2020

Solid oxide fuel cell (SOFC) have attracted much attention due to clean, efficient and environmental-friendly generation of electricity for next-generation energy conversion devices. Recently, many studies have been reported on improving the performance of SOFC electrodes and electrolytes by applying atomic layer deposition (ALD) process, which has advantages of excellent film quality and conformality, and precise control of film thickness by utilizing its unique self-limiting surface reaction. ALD process with these advantages has been shown to provide functional ceramic interfaces for SOFC electrodes and electrolytes. In this article, recent examples of successful functionalization and stabilization on SOFC electrodes and electrolytes by the application of ALD process for realizing high performance SOFC cells are reported.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.236-237
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• 2007

A single-wall carbon nanotube (SWNT) transparent conductive film (TCF) was fabricated using a simple inkjet printing method. The TCF could be selectively patterned by controlling the dot size to diameters as small as 34${\mu}m$. In thisrepeatable and scalable process, we achieved 71% film transmittance and a resistance of 900 ohm/sq sheet with an excellent uniformity, about $\pm$5% deviation overall. Inkjet printing of SWNT is substrate friendly and the TCF is printed on a flexible substrate. This method of fabrication using direct printing permits mass production of TCF in a large area process, reducing processing steps and yielding low-cost TCF fabrications on a designated area using simple printing.

• Elastomers and Composites
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• v.54 no.1
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• pp.35-39
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• 2019

Four different polymer compounds were prepared from four kinds of plasticizers, viz. di-2-ethylhexyl azelate (DOZ), di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl sebacate (DOS), and di-2-butyl sebacate (DBS), for making cable sheaths for ships. Ethylene-vinyl acetate and ethylene-propylene-diene-copolymer as matrix polymers and ethylene-vinyl acetate grafted maleic anhydride as a coupling agent were compounded with a flame retardant, crosslinking agent, filler, and other additives, besides the plasticizer to obtain the polymer compounds. The polymer containing DOZ showed the highest MH and ${\Delta}T$ in the rheology test, while that containing DBS was found to have the lowest tensile strength and highest elongation because of low ${\Delta}T$. The four polymers showed similar values (31.7-31.9) for flame resistance, while the polymer containing DOZ showed the highest value for cold resistance.

• Composites Research
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• v.19 no.6
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• pp.38-42
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• 2006

Wood Plastic Composite(WPC) has been introduced as a new constructional material in Europe and North America. The maintenance-free durability against weather was accepted by customers and the environment-friendly merits ignited the abrupt increase of market size. Domestic major companies have kicked off the WPC business at the market of outdoor constructional materials. Due to the high contents of natural wood fiber, the production equipments should be modified to remove the moisture, to prevent thermal degradation and to promote output rates. Materials including functional fillers play a critical role in rheological properties, which affects the physical and mechanical properties of the last products. More research might be performed for synergy effects combined by various academic fields from mechanical and chemical engineering to polymer process and material science.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.535-548
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• 2022

Recently, the construction industry has focused on eco-friendly materials instead of traditional materials due to their harmful effects on the environment. To this end, biopolymers are among proper choices to improve the geotechnical behavior of problematic soils. In the current study, serish biopolymer is introduced as a new binder for the purpose of sand improvement. Serish is a natural polysaccharide extracted from the roots of Eremurus plant, which mainly contains inulins. The effect of serish biopolymer on sand treatment has been investigated through performing unconfined compressive strength (UCS), California bearing ratio (CBR), as well as wind erosion tests. The results demonstrated that serish increased the compressive strength of dune sand in both terms of UCS and CBR. Also, wind erosion resistance of the sand was considerably improved as a result of treatment with serish biopolymer. A microstructural study was also conducted via SEM images; it can be seen that serish coated the sand particles and formed a strong network.

• Journal of Engineering Education Research
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• v.13 no.5
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• pp.8-14
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• 2010

This study intends to study about the blade performance loss occurred due to the variation in the shape of an airfoil from attachment/non-attachment of an erosion shield for the hovercraft. The model in this study has used NACA44XXseries, has designed NACA44XX-series by using the Auto CAD, and it designed the shape that has attached an erosion shield to this model according to the thickness and length. By using these models, a grid was generated by GAMBIT and the lift coefficient ($C_l$) and the drag coefficient ($C_d$) were calculated FLUENT code for flow analysis. Through this, the $C_l$ and $C_d$ have calculated and compared the lift-to-drag ratio that an indicator of airfoil performance according to the shape and attachment/non-attachment of erosion shield.

• International Journal of Concrete Structures and Materials
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• v.18 no.3E
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• pp.165-171
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• 2006

Environment-friendly materials are increasingly used as building construction materials nowadays, and the market share of those is growing. Accordingly, the research and developments in terms of environmental value are progressing steadily now. The main characteristics of environmental products are far-infrared radiation, negative-ion emission, electromagnetic wave shielding, and antimicrobial property. These products are often used in mortar and as spray on the finishing material. Nevertheless, there are hardly any research on the functional properties of concrete, the main material in construction field. Thus, we evaluated such basic properties of concrete as slump, compressive strength and air content while using such functional materials as sericite, wood-pattern sandstone, carbon black and nano-metric silver solution to focus on their functional properties like far-infrared radiation, negative ion emission, electro magnetic wave shielding, and antimicrobial activity in this research. The results indicated that the most useful material in the functional materials was carbon black. Sericite and nano-metric silver solution had a little effect on the functional property. Moreover, although wood-pattern sandstone had very high functional property, it exhibited too low compressive strength to be applied, to concrete as a factory product. Antimicrobial property of nano-metric silver solution in the concrete was not clear demonstrated, but if these specimens were to be aged in $CO_2$ gas for a long time, it might be apparent.

• Journal of the Korea Furniture Society
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• v.22 no.3
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• pp.219-229
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• 2011

Sick building syndrome symptoms that are experienced by building occupants may be caused by toxic substances such as formaldehyde and VOCs, which are known to be emitted from building materials and wood composite products such as wood-based panel, furniture, engineered flooring and construction adhesive. In Korea, the use of wood composite products for indoor environments has increased over the last decade. Recently, wood composite products have been installed in approximately 95% of newly constructed residential buildings. The use of these products has resulted in problems related to human health, and consequently a realization about the importance of indoor air quality. In addition, consumer demand is increasing for natural materials because conventional building materials and wood composite products are made by adding urea-formaldehyde resin or they contain formaldehyde-based resin. More recently, many efforts have been made to reduce formaldehyde emission from building materials that laid in the indoor environment. Especially, if conventional formaldehyde-based adhesives are replaced with green adhesives for residential spaces, it is possible to reduce most of the emission amounts of formaldehyde in indoor environments. In line with this expectation, many researches are being conducted using natural materials such as tannin and cashew nut shell liquid (CNSL). This study discussed the affects and possibilities of green adhesives to reduce formaldehyde emission in indoor environments.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.51-51
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• 2012

There is a growing interest in innovative chemical synthesis in microreactors owing to high efficiency, selectivity, and yield. In microfluidic systems, the low-volume spatial and temporal control of reactants and products offers a novel method for chemical manipulation and product generation. Glass, silicon, poly(dimethylsiloxane) (PDMS), and plastics have been used for the fabrication of miniaturized devices. However, these materials are not the best due to either of low chemical durability or expensive fabrication costs. In our group, we have recently addressed the demand for economical resistant materials that can be used for easy fabrication of microfluidic systems with reliable durability. We have suggested the use of various specialty polymers such as silicon-based inorganic polymers and fluoropolymer, flexible polyimide (PI) films that have not been used for microfluidic devices, although they have been used for other areas. And inexpensive lithography techniques were used to fabricate Lab-on-a-Chip type of microreactors with differently devised microchannel design. These microreactors were demonstrated for various synthetic reactions: liquid, liquid-gas organic chemical reactions in heterogeneous catalytic processes, syntheses of polymer and non-trivial inorganic materials. The microreactors were inert, and withstand even harsh conditions, including hydrothermal reaction. In addition, various built-in microstructures inside the microchannels, for example Pd decorated peptide nanowires, definitely enhance the uniqueness and performance of microreactors. These user-friendly Lab-on-a-Chip devices are useful alternatives for chemist and chemical engineer to conventional chemical tools such as glass.

• Korean Journal of Health Education and Promotion
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• v.3 no.1
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• pp.55-70
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• 2001

Background: Alcohol and tobacco use are two major behavioral risk factors implicated in increased morbidity and mortality. Since both substances are widely used in Korea, a concerted effort is currently underway to reduce the use of tobacco and alcohol in Korea. Objectives: Efforts directed toward preparing health promotion planners and health educators from local health departments to organize and implement community-wide interventions to reduce the proportion of people smoking and reduce the average level of alcohol consumption in the community. Methods: Comprehensive multi-media health promotion materials were developed based on health behavior theories and strategies. The materials were developed to introduce a user-oriented developmental approach by making messages more persuasive and organizing content in a user-friendly manner. Health educators from all local health departments in the country were trained in the use of the materials, to enable them to develop community interventions to reduce smoking and drinking. Implications for Practitioners: The process followed in developing the health intervention materials is described in detail to assist practitioners who need to develop effective programs to reduce the use of tobacco and alcohol. Sections of the report explain health intervention theories, specific program activities to include in an intervention, development, organization, evaluation, choosing a target audience, choosing goals of an intervention, and methods of making program content vivid and persuasive.