• International Journal of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.148-155
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• 2020

This study investigated learners' perceptions of using self-generated listening materials based on Text to Speech. After taking an online training session to learn how to make listening materials for extensive listening practice outside the classroom, the learners were engaged in practice with self-generated listening materials for 10 weeks in a self-directed way. The results show that a majority of the learners found the TTS-based listening materials helpful to reduce anxiety toward listening and enhance self-confidence and motivation, with a positive effect on improving their listening ability. The learners' general satisfaction can be attributed to some beneficial features of TTS-based listening material, including freedom to choose what they want to learn, convenient accessibility to the material, availability of various native speakers' voices, and novelty of digital tools. This suggests that TTS-based digital listening materials can be a useful educational tool to support learners' self-directed listening practice outside the classroom in EFL settings.

• Korean Institute of Interior Design Journal
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• v.14 no.6 s.53
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• pp.228-235
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• 2005

This study analyzes the new possibility of design through the research for the expression of cladding design architectural materials, and applies to connection with creative design concept. In these modern days, architectural materials became the subject of expression as itself thanks to the development of new technology and materials. The physical properties of materials and their beauty value made possible the variety and possibility of expression in space design. The expressional properties of materials can lead mutual communication between commodity and brand by association, presenting brand image and the distinction of its value. Therefore, the trends of designed material expression in space design according to modern aspect can offer the possibility of material space design for ahead. This study suggest an alternative idea for revitalizing design by materials.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.279-282
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• 2002

With the development of industrial society, the interest of new material is growing even in machining center. Composite materials in the new materials are superior to the metals In measure stability of strength, modulus and heat, moreover when mould is prepared, it can be done net shape manufacturing so it can be used widely in all sorts of machine parts, interior materials of car structural construct ions, the space aerial industry, ship materials, sports goods and so on. Therefore in this study, the property of processing drill on CFRP in composite materials by experimental study and some problems were examined.

• Transactions on Electrical and Electronic Materials
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• v.5 no.5
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• pp.185-188
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• 2004

Phase transitions from the amorphous to crystalline states, and vice versa, of GST(GeSbTe) and AST(AsSbTe) thin films by applying electrical pulses have been studied. These materials can be used as nonvolatile memory devices. The thickness of ternary chalcogenide thin films is approximately 100 nm. Upper and lower electrodes were made of AI. I-V characteristics after impressing the variable pulses to GST and AST films. Tc(crystallization temperature) of AST system is lower than that of the GST system, so that the current pulse width of crystallization process can be decreased.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.758-760
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• 2008

Nanoporous AAO (Anodic Aluminum Oxide) membranes have many advantages as a template for variety of magnetic materials. Materials can be embedded into the pores by electrodeposition, sputtering or magnetic-field-assisted infiltration of magnetic nanoparticles. This work focuses on the fabrication of the magnetic structures in the AAO templates by electrodeposition. Our method allows the controlled growth of Co nanostructures within the porous alumina membrane in the form of dots, rods and long wires. The shape of Co nanostructures has been investigated by field emission scanning electron microscope (FESEM). The magnetic hysteresis loops of Co nanostructures were measured using SQUID at 5 K and 300 K. The magnetic properties of the Co nanostructures are proportional to their aspect ratios and can be controlled by changing the aspect ratios.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.258-258
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• 2001

Fiber-reinforced materials have highly favorable mechanical properties. and their strength-to-weight ratios are superior to those of most alloys. When compared to metals they offer many other advantages as well. including non-corrosiveness. translucency. good bonding properties. and ease ofrepair. Fiber-reinforced materials can be categorized to pre-impregnated. impregnation required. dental laboratory products. chairside products and prefabricated posts. so it is not suprising that fiber-reinforced composites have potential for use in many applications in dentistry. Fiber-reinforced materials can be utilized in frameworks for crowns. anterior or posterior fixed prostheses. chairs ide tooth replacements. periodontal splints. customized posts. prefabricated posts. orthodontic retention. denture reinforcements and in implants dentistry. To realize the full potential of using fiber-reinforced composite restorations. it is essential that the clinician and laboratory technician understand concepts of tooth preparation and framework design. Also practitioner may appreciate the background information and other details about the materials themselves so that identify the rationale for their use in various clinical situations. select well-suited materials. and carry out related procedures. Understanding the material properties and take many attentions. fiber-reinforced materials will give more esthetic. more easy. more strong and more reliable restorations.ations.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.346-347
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• 2006

New manufacturing processes, such as thermochemical, mechanochemical and chemical vapor condensation processes have been developed to obtain nanostructured WC/Co materials. Nanoscale size WC/Co composite powders of near 100-150nm can be synthesizes by thermochemical and mechanochemical processes using water soluble precursors. Non-agglomerated and nano sized WC powder can be synthesized by the chemical vapor condensation process using metallorganic precursors as starting materials. In this paper, the scientific and technical issues on synthesis and consolidation of nanostructured WC/Co alloys produced by new chemical processes are introduced.

• Journal of Sensor Science and Technology
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• v.29 no.6
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• pp.374-381
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• 2020

Hydrogen gas has attracted considerable attention as a promising candidate for future energy resources because of its eco-friendly characteristics; however, its highly combustible characteristics should be thoroughly examined to preclude potential disasters. In this regard, a highly sensitive method for the selective detection of H₂ is extremely important. To achieve excellent H₂ selectivity, the utilization of a metal-organic framework (MOF) membrane can physically screen interfering gas molecules by restricting the size of kinetic diameters that can penetrate its nanopores. This paper summarizes the various endeavors of researchers to utilize the MOF molecular sieving layer for the development of highly selective H₂ sensors. Further, the review affords useful insights into the development of highly reliable H₂ sensors.

• Elastomers and Composites
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• v.59 no.1
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• pp.22-33
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• 2024

Passive radiative cooling is a promising technology for cooling objects without energy input. Passive radiative cooling works by radiating heat from the surface, which then passes through the atmosphere and into space. Achieving efficient passive radiative cooling is mainly accomplished by using materials with high emissivity in the atmospheric window (8-13 ㎛). Research has shown that polymers tend to exhibit high emissivity in this spectral range. In addition to elastomers, other materials with potential for passive radiative cooling include metal oxides, carbon-based materials, and polymers. The structure of a passive radiative cooling device can affect its cooling performance. For example, a device with a large surface area will have a greater amount of surface area exposed to the sky, which increases the amount of thermal radiation emitted. Passive radiative cooling has a wide range of potential applications, including building cooling, electronics cooling, healthcare, and transportation. Current research has focused on improving the efficiency of passive radiative cooling materials and devices. With further development, passive radiative cooling can significantly affect a wide range of sectors.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.330-337
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• 2021

3D printing is not only at the fundamental study and small-scale level, but has recently been producing buildings that can be inhabited by people. Buildings require a lot of cost and labor to work on the form work, but if 3D printing is applied to the building, the construction industry is received attention from technologies using 3D printing as it can reduce the construction period and cost. 3D printing technology for buildings can be divided into structural and non-structural materials, of which 3D printing is applied to non-structural materials. Because 3D printing needs to be additive manufacturing, control such as curing speed and workability is needed. Since cement mortar has a large shrinkage due to evaporation of water, cement polymer dispersion is used to improve the hardening speed, workability, and adhesion strength. The addition of polymer dispersion to cement mortar improves the tensile strength and brittleness between the cement hydrate and the polymer film. Cement mortar using polymer materials can be additive manufacturing but it has limited height that can be additive manufacturing due to its high density. When light-weight materials are mixed with polymer cement mortar, the density of polymer cement mortar is lowered and the height of additive manufacturing, so it is essential to use light-weight materials. However, the use of EVA redispersible polymer powder and light-weight materials, additional damage such as cracks in cement mortar can occur at high temperatures such as fires. This study produced a test specimen incorporating light-weight materials and EVA redispersible polymer powder to produce exterior building materials using 3D printing, and examined flame resistance performance through water absorption rate, length change rate, and cone calorimeter test and non-flammable test. From the test result, the test specimen using silica sand and light-weight aggregate showed good flame resistance performance, and if the EVA redispersible polymer powder is applied below 5%, it shows good flame resistance performance.