간행물
한국재료학회지 KCI 등재 SCOPUS Korean Journal of Materials Research
- 발행기관 한국재료학회
- 자료유형 학술지
- 간기 월간
- ISSN 2799-8525 (Print)2799-8681 (Online)
- 수록기간 1991 ~ 2024
- 주제분류 공학 > 재료공학 공학 분류의 다른 간행물
- 십진분류KDC 530DDC 620
권호리스트/논문검색
제27권 제11호 (2017년 11월) 10건
1.
2017.11
구독 인증기관 무료, 개인회원 유료
Self-cleaning and photocatalytic TiO2 thin films were prepared by a facile sol-gel method followed by spin coating using peroxo titanic acid as a precursor. The as-prepared thin films were heated at low temperature(110 °C) and high temperature (400 °C). Thin films were characterized by X-ray diffraction(XRD), Field-emission scanning electron microscopy(FESEM), UVVisible spectroscopy and water contact angle measurement. XRD analysis confirms the low crystallinity of thin films prepared at low temperature, while crystalline anatase phase was found the for high temperature thin film. The photocatalytic activity of thin films was studied by the photocatalytic degradation of methylene blue dye solution. Self-cleaning and photocatalytic performance of both low and high temperature thin films were compared.
4,000원
2.
2017.11
구독 인증기관 무료, 개인회원 유료
Ceramic ink-jet printing has become a widespread technology in ceramic tile and ceramicware industries, due to its capability of manufacturing products on demand with various designs. Generally, thermally stable ceramic inks of digital primary colors(cyan, magenta, yellow, black) are required for ink-jet printing of full color image on ceramic tile. Here, we synthesized an aqueous glass-ceramic ink, which is free of Volatile organic compound(VOC) evolution, and investigated its inkjet printability. CoAl2O4 inorganic pigment and glass frit were dispersed in aqueous solution, and rheological behavior was optimized. The formulated glass-ceramic ink was suitably jetted as single sphere-shaped droplets without satellite drops. After ink-jet printing and firing processes, the printed glass-ceramic ink pattern on glazed ceramic tile was stably maintained without ink spreading phenomena and showed an improved scratch resistance.
4,000원
3.
2017.11
구독 인증기관 무료, 개인회원 유료
We demonstrated a CNT synaptic transistor by integrating 6,6-phenyl-C61 butyric acid methyl ester(PCBM) molecules as charge storage molecules in a polyimide(PI) dielectric layer with carbon nanotubes(CNTs) for the transistor channel. Specifically, we fabricated and compared three different kinds of CNT-based synaptic transistors: a control device with Al2O3/PI, a single PCBM device with Al2O3/PI:PCBM(0.1 wt%), and a double PCBM device with Al2O3/PI:PCBM(0.1 wt%)/PI:PCBM(0.05 wt%). Statistically, essential device parameters such as Off and On currents, On/Off ratio, device yield, and longterm retention stability for the three kinds of transistor devices were extracted and compared. Notably, the double PCBM device exhibited the most excellent memory transistor behavior. Pulse response properties with postsynaptic dynamic current were also evaluated. Among all of the testing devices, double PCBM device consumed such low power for stand-by and its peak current ratio was so large that the postsynaptic current was also reliably and repeatedly generated. Postsynaptic hole currents through the CNT channel can be generated by electrons trapped in the PCBM molecules and last for a relatively short time(~ hundreds of msec). Under one certain testing configuration, the electrons trapped in the PCBM can also be preserved in a nonvolatile manner for a long-term period. Its integrated platform with extremely low stand-by power should pave a promising road toward next-generation neuromorphic systems, which would emulate the brain power of 20W.
4,000원
4.
2017.11
구독 인증기관 무료, 개인회원 유료
In this study, an Al-0.7wt%Fe-0.2wt%Mg-0.2wt%Cu-0.02wt%B alloy was designed to fabricate an aluminum alloy for electrical wire having both high strength and high conductivity. The designed Al alloy was processed by casting, extrusion and drawing processes. Especially, the drawing process was done by severe deformation of a rod with an initial diameter of 12 mm into a wire of 2 mm diameter; process was equivalent to an effective strain of 3.58, and the total reduction in area was 97 %. The drawn Al alloy wire was then annealed at various temperatures of 200 to 400 °C for 30 minutes. The mechanical properties, microstructural changes and electrical properties of the annealed specimens were investigated. As the annealing temperature increased, the tensile strength decreased and the elongation increased. Recovery or/and recrystallization occurred as annealing temperature increased, and complete recrystallization occurred at annealing temperatures over 300 °C. Electric conductivity increased with increasing temperature up to 250 °C, but no significant change was observed above 300 °C. It is concluded that, from the viewpoint of the mechanical and electrical properties, the specimen annealed at 350 oC is the most suitable for the wire drawn Al alloy electrical wire.
4,000원
5.
2017.11
구독 인증기관 무료, 개인회원 유료
Si3N4 is a ceramic material attracting attention in many fields because of its excellent abrasion resistance. In addition, Ti and TiAl alloys are metals used in a variety of high temperature environments, and have attracted much attention because of their high strength and high melting points. Therefore, study of the interface reaction between Si3N4 / Ti and Si3N4 / TiAl can be a useful practice to identify phase selection and diffusion control. In this study, Si3N4 / Ti5Si3 + TiN / TiN / Ti diffusing pairs were formed in the Si3N4 / Ti interfacial reaction and Si3N4 / TiN(Al) / Ti3Al / TiAl diffusion pathway was identified in the Si3N4 / TiAl interfacial reaction. The diffusion layers of the interface reactions were identified and, to investigate the kinetics of the diffusion layer, the integrated diffusion coefficients were estimated.
4,000원
6.
2017.11
구독 인증기관 무료, 개인회원 유료
We investigated a Leidenfrost effect in the growth of ZnO nanostructures on silicon substrates by ultrasonic-assisted spray pyrolysis deposition(SPD). Structural and optical properties of the ZnO nanostructures grown by varying the growth parameters, such as substrate temperature, source concentration, and suction rate of the mist in the chambers, were investigated using field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence spectrum analysis. Structural investigations of the ZnO nanostructures showed abnormal evolution of the morphologies with variation of the substrate temperatures. The shape of the ZnO nanostructures transformed from nanoplate, nanorod, nanopencil, and nanoprism shapes with increasing of the substrate temperature from 250 to 450 °C; these shapes were significantly different from those seen for the conventional growth mechanisms in SPD. The observed growth behavior showed that a Leidenfrost effect dominantly affected the growth mechanism of the ZnO nanostructures.
4,000원
7.
2017.11
구독 인증기관 무료, 개인회원 유료
Mesoporous carbon nanofibers as electrode material for electrical double-layer capacitors(EDLCs) are fabricated using the electrospinning method and carbonization. Their morphologies, structures, chemical bonding states, porous structure, and electrochemical performance are investigated. The optimized mesoporous carbon nanofiber has a high sepecific surface area of 667 m2 g−1, high average pore size of 6.3 nm, and high mesopore volume fraction of 80 %, as well as a unifom network structure consiting of a 1-D nanofiber stucture. The optimized mesoporous carbon nanofiber shows outstanding electrochemical performance with high specific capacitance of 87 F g−1 at a current density of 0.1 A g−1, high-rate performance (72 F g−1 at a current density of 20.0 A g−1), and good cycling stability (92 F g−1 after 100 cycles). The improvement of the electrochemical performance via the combined effects of high specific surface area are due to the high mesopore volume fraction of the carbon nanofibers.
4,000원
8.
2017.11
구독 인증기관 무료, 개인회원 유료
In this study, we investigated the overpotential of precipitation related to the catalytic activity of electrodes on the initial process of electrodeposition of Co and Co-Ni alloys on polycrystalline Cu substrates. In the case of Co electrodeposition, the surface morphology and the magnetic property change depending on the film thickness, and the relationship with the electrode potential fluctuation was shown. Initially, the deposition potential(−170 mV) of the Cu electrode as a substrate was shown, the electrode potential(Edep) at the Ton of electrodeposition and the deposition potential(−600 mV) of the surface of the electrodeposited Co film after Toff and when the pulse current was completed were shown. No significant change in the electrode potential value was observed when the pulse current was energized. However, in a range of number of pulses up to 5, there was a small fluctuation in the values of Edep and Eimm. In addition, in the Co-Ni alloy electrodeposition, the deposition potential(−280 mV) of the Cu electrode as the substrate exhibited the deposition potential(−615 mV) of the electrodeposited Co-Ni alloy after pulsed current application, the Edep of electrodeposition at the Ton of each pulse and the Eimm at the Toff varied greatly each time the pulse current was applied. From 20 % to less than 90% of the Co content of the thin film was continuously changed, and the value was constant at a pulse number of 100 or more. In any case, it was found that the shape of the substrate had a great influence.
4,000원
9.
2017.11
구독 인증기관 무료, 개인회원 유료
Mahesh P. Suryawanshi, Seonghyeop Kim, Uma V. Ghorpade, Umesh P. Suryawanshi, Jun Sung Jang, Myeng Gil Gang, Jin Hyeok Kim, Jong Ha Moon
We report facile solution processing of mesoporous hematite (α-Fe2O3) thin films for high efficiency solar-driven water splitting. Fe2O3 thin films were prepared on fluorine doped tin oxide(FTO) conducting substrates by spin coating of a precursor solution followed by annealing at 550 oC for 30 min. in air ambient. Specifically, the precursor solution was prepared by dissolving non-toxic FeCl3 as an Fe source in highly versatile dimethyl sulfoxide(DMSO) as a solvent. The as-deposited and annealed thin films were characterized for their morphological, structural and optical properties using field-emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and UV-Vis absorption spectroscopy. The photoelectrochemical performance of the precursor (α-FeOOH) and annealed (α-Fe2O3) films were characterized and it was found that the α-Fe2O3 film exhibited an increased photocurrent density of ~0.78 mA/cm2 at 1.23 V vs. RHE, which is about 3.4 times higher than that of the α-FeOOH films (0.23 mA/cm2 at 1.23 V vs. RHE). The improved performance can be attributed to the improved crystallinity and porosity of α-Fe2O3 thin films after annealing treatment at higher temperatures. Detailed electrical characterization was further carried out to elucidate the enhanced PEC performance of α-Fe2O3 thin films.
4,000원
10.
2017.11
구독 인증기관 무료, 개인회원 유료
In the present study the microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes was characterized and identified based on various microstructure analysis methods including optical and scanning electron microscopy, and electron backscatter diffraction(EBSD). Although low-carbon steels are usually composed of α-ferrite and cementite(Fe3C) phases, they can have complex microstructures consisting of ferrites with different size, morphology, and dislocation density, and secondary phases dependent on rolling and accelerated cooling conditions. The microstructure of lowcarbon steels investigated in this study was basically classified into polygonal ferrite, acicular ferrite, granular bainite, and bainitic ferrite based on the inverse pole figure, image quality, grain boundary, kernel average misorientation(KAM), and grain orientation spread(GOS) maps, obtained from EBSD analysis. From these results, it can be said that the EBSD analysis provides a valuable tool to identify and quantify the complex microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes.
4,000원
