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
제18권 제8호 (2008년 8월) 10건
1.
2008.08
구독 인증기관 무료, 개인회원 유료
Pt-loaded carbon black for the catalyst of a PEM fuel cell was synthesized with different molar ratios of polyvinylpyrrolidone and H2PtCl6 solution to improve the dispersion of Pt nanoparticles on carbon black and decrease the size of Pt nanoparticles. From transmission electron microscopy results, Pt nanoparticles of a size of approximately 2 nm were highly dispersed when the polyvinylpyrrolidone concentration was 10mM. The electrochemical activity of the synthesized Pt/C catalysts was investigated by cyclic voltammetry, showing that the as-synthesized Pt-loaded carbon black catalyst had the best activity at a polyvinylpyrrolidone concentration of 10 mM.
4,000원
2.
2008.08
구독 인증기관 무료, 개인회원 유료
The properties of pyrolytic carbon (PyC) deposited from C2H2 and a mixture of C2H2/C3H6 on ZrO2 particles in a fluidized bed reactor were studied by adjusting the deposition temperature, reactant concentration, and the total gas flow rate. The effect of the deposition parameters on the properties of PyC was investigated by analyzing the microstructure and density change. The density could be varied from 1.0 g/cm3 to 2.2 g/cm3 by controlling the deposition parameters. The density decreased and the deposition rate increased as the deposition temperature and reactant concentration increased. The PyC density was largely dependent on the deposition rate irrespective of the type of the reactant gas used.
4,000원
3.
2008.08
구독 인증기관 무료, 개인회원 유료
In this research, fine-structure TiO2 bulks were fabricated in a combined application of magnetic pulsed compaction (MPC) and subsequent sintering and their densification behavior was investigated. The obtained density of TiO2 bulk prepared via the combined processes increased as the MPC pressure increased from 0.3 to 0.7 GPa. Relatively higher density (88%) in the MPCed specimen at 0.7 GPa was attributed to the decrease of the inter-particle distance of the pre-compacted component. High pressure and rapid compaction using magnetic pulsed compaction reduced the shrinkage rate (about 10% in this case) of the sintered bulks compared to general processing (about 20%). The mixing conditions of PVA, water, and TiO2 nano powder for the compaction of TiO2 nano powder did not affect the density and shrinkage of the sintered bulks due to the high pressure of the MPC.
4,000원
4.
2008.08
구독 인증기관 무료, 개인회원 유료
Al2O3 sol with long-term stability was prepared by mechanical milling. Thin films were evaluated and created for use as coating materials. The particle size of the manufactured sol was 98 nm when 2 wt% of nitric acid was added. This indicates that the viscosity of the sol is 12 cps and that it has long-term stability. The thickness of the thin films, which varied from 100 nm to 500 nm, could be managed by adjusting the draw rate and the amount of an organic additive. A thin film heated to 500˚C indicated a hydrophilic property against water and excellent permeability against a visible ray.
4,000원
5.
2008.08
구독 인증기관 무료, 개인회원 유료
The effects of an addition of ZrO2 on the microstructure and electrical properties of MgO films as a protective layer for AC plasma display panels were investigated. MgO + a 200 ppm ZrO2 protective layer prepared by e-beam evaporation exhibited a secondary electron emission coefficient (γ) that was improved by 21% compared to that of a pure MgO protective layer. The relative density and Vickers hardness increased with a further addition of ZrO2. These results suggest that the discharge properties and optical properties of MgO protective layers are closely related to the relative density and Vickers hardness. The good optical and electrical properties of γ, at 0.080, a grain size of 19 μm and an optical transmittance of 91.93 % were obtained for the MgO + 200 ppm ZrO2 protective layer sintered at 1700˚C for 5 hrs.
4,000원
6.
2008.08
구독 인증기관 무료, 개인회원 유료
The mechanical property of a phosphore layer was investigated by measuring the resolution (LP/mm) and by positron annihilation spectroscopy and SEM. Image plate samples containing the phosphore layer were irradiated by X-rays in a hospital numerous times over a course of several years. The LP/mm values of a (Ba,Sr)FBr : Eu image plate irradiated by X-rays varied between 2.2 and 2.0 over a period of four years. Coincidence Doppler Broadening (CDB) positron annihilation spectroscopy was used to analyze defect structures. The S parameters of the samples from hospital use varied from 0.6219 to 0.6232. There was a positive relationship between the time of exposure to the X-rays and the S parameters. Most of the defects were found to have been generated by X-rays.
4,000원
7.
2008.08
구독 인증기관 무료, 개인회원 유료
Titanium oxide films and powders are attached onto carbon cloths via RF reactive sputtering and an epoxy resin mixture, respectively. TiO2/carbon composite materials were used to investigate the photoelectrochemical degradation of perchlorate ions in water. The energy band gaps of the RF-sputtered TiO2 thin films ranged from 3.35-3.44 eV. A photocurrent of the powdered TiO2 as illuminated by ultra-violet light for 30 min. was 2.79 mA/cm2. Perchlorate ions in water were shown to be degradable by a UV-illuminated TiO2 powder/carbon/Nafion/carbon composite.
4,000원
8.
2008.08
구독 인증기관 무료, 개인회원 유료
SnO nanosheets were prepared at room temperature through a reaction between an aqueous solution of SnCl2, N2F4, and NaOH and were converted into SnO2 nanosheets without a morphological change. The SnO nanosheets were formed through a dissolution-recrystallization mechanism. Uniform and well-dispersed SnO nanosheets with the round-shape morphology were attained when the solution was treated by ultrasonic sound immediately after the addition of NaOH. The SnO2 nanosheets prepared by means of solution reduction under the ultrasonic treatment, and subsequent oxidation at 600˚C showed a high level of gas sensitivity to C2H5OH and CH3COCH3.
4,000원
9.
2008.08
구독 인증기관 무료, 개인회원 유료
Yu, Fucheng, Gao, Cunxu, Parchinskiy, P.B., Chandra, Sekar.P.V., Kim, Do-Jin, Kim, Chang-Soo, Kim, Hyo-Jin, Ihm, Young-Eon
Samples of GaMnAs, GaMnAs codoped with Be, and GaMnAs simultaneously codoped with Be and Mg were grown via low-temperature molecular beam epitaxy (LT-MBE). Be codoping is shown to take the Ga sites into the lattice efficiently and to increase the conductivity of GaMnAs. Additionally, it shifts the semiconducting behavior of GaMnAs to metallic while the Mn concentration in the GaMnAs solid solution is reduced. However, with simultaneous codoping of GaMnAs with Be and Mg, the Mn concentration increases dramatically several times over that in a GaMnAs sample alone. Mg and Be are shown to eject Mn from the Ga sites to form MnAs and MnGa precipitates.
4,000원
10.
2008.08
구독 인증기관 무료, 개인회원 유료
Mg-doped and In-Mg co-doped p-type GaN epilayers were grown in a low-pressure metal organic chemical vapor deposition technique. The effect of In doping on the p-GaN layer was studied through photoluminescence (PL), persistent photoconductivity (PPC), and transmission electron microscopy (TEM) at room temperature. For the In-doped p-GaN layer, the PL intensity increases significantly and the peak position shifts to 3.2 eV from 2.95 eV of conventional p-GaN. Additionally, In doping greatly reduces the PPC, which was very strong in conventional p-GaN. A reduction in the dislocation density is also evidenced upon In doping in p-GaN according to TEM images. The improved optical properties of the In-doped p-GaN layer are attributed to the high crystalline quality and to the active participation of incorporated Mg atoms.
3,000원
