The relation among electronic structure, chemical bond and thermoelectric property of Ca3Co2O6 and Cu-doped is studied by first-principle theory. The results indicate that the highest valence band(HVB) and the lowest ...
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Bulk heterojunction polymer solar cells, based on thin films of polymer/fullerene blends, have progressed rapidly during the past few years. Efficiencies over 6% have been achieved in research lab.. In this chapter, a...
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Silver nanoparticles were prepared by pulsed wire discharge (PWD) using silver wire in deionized water at various relative energy (K) from 10 to 98, which is ratio of the charged energy of the capacitor in the electri...
Silver nanoparticles were prepared by pulsed wire discharge (PWD) using silver wire in deionized water at various relative energy (K) from 10 to 98, which is ratio of the charged energy of the capacitor in the electrical circuit to the vaporization energy of the wire. From energy deposition calculated by the measured voltage and current waveforms, deposited energy of the wire was increased with increasing K. From X-ray diffraction (XRD) analysis, prepared nanoparticles were phase identified as silver. From transmission electron microscopy observations, the shape of prepared silver nanoparticles were spherical and the median particle diameter (D50) and the geometric standard deviation (σg) were calculated from the particle distribution. D50 was decreased from 34 to 19 nm with increasing K. The particle size in prepared by PWD in liquid media can be controlled by K.
A novel method based on radio frequency magnetron sputtering tailored to the deposition of low residual stress and adherent c-BN thin films on silicon substrates was developed. In this study, the effect of noble gas (...
A novel method based on radio frequency magnetron sputtering tailored to the deposition of low residual stress and adherent c-BN thin films on silicon substrates was developed. In this study, the effect of noble gas (Kr, Ar, Ne and He) added in Ar gas during sputtering on the residual stress and the c-BN content has been investigated. As a result, it was found that the residual stress of c-BN thin film decreased with increasing the helium gas flow rate within argon gas.
The small punch creep (SP-C) test technique is a new method which is applied to evaluate the high temperature creep properties of materials by using miniature specimen. In the present paper, the Finite Element Method ...
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Polypyrrole-coated V 2 O 5 nanotubes hybrid materials have been synthesized through an in situ polymerization of pyrrole monomers in the presence of prepared V 2 O 5 nanotubes. The hybrids were characterized by scan...
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ISBN:
(纸本)9781424435432;9781424435449
Polypyrrole-coated V 2 O 5 nanotubes hybrid materials have been synthesized through an in situ polymerization of pyrrole monomers in the presence of prepared V 2 O 5 nanotubes. The hybrids were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Experimental data showed that polypyrrole was uniformly coated on the surface of the V 2 O 5 nanotubes, and the polypyrrole coating is 30 nm thick. Gas sensing tests showed that the hybrids possessed very high sensitivity to ethanol gas at room temperature, implying its potential application for gas sensors.
Optical transparency was achieved at infrared region and overall translucent silicon nitride was fabricated using hot press sintering (HPS). The increase in h-BN content decreased the optical transparency. Microstruct...
Optical transparency was achieved at infrared region and overall translucent silicon nitride was fabricated using hot press sintering (HPS). The increase in h-BN content decreased the optical transparency. Microstructral observations shows that the optical, mechanical and tribological properties of BN dispersed polycrystalline Si3N4 ceramics were affected by the density, α:β-phase ratio and content of h-BN in sintered ceramics. The hot pressed samples were prepared from the mixture of α-Si3N4, AlN, MgO and h-BN at 1850°C. The composite contained from 0.25 to 2 mass % BN powder with sintering aids (9% AlN + 3% MgO). Maximum transmittance of 57% was achieved for 0.25 mass % BN doped Si3N4 ceramics. Fracture toughness was increased and wear volume and friction coefficient were decreased with increase in BN content.
Y2O3, Er2O3 and Nd2O3 doped polycrystalline silicon nitride ceramics were prepared by hot press sintering method at 1850°C and 30 MPa pressure. 1 wt.% of each rare earth oxides (REO) were sintered with 3 wt.% MgO...
Y2O3, Er2O3 and Nd2O3 doped polycrystalline silicon nitride ceramics were prepared by hot press sintering method at 1850°C and 30 MPa pressure. 1 wt.% of each rare earth oxides (REO) were sintered with 3 wt.% MgO, 9 wt.% AlN and 87 wt.% α-*** optical, mechanical and tribological properties of REO doped polycrystalline silicon nitride ceramics were investigated. Optical transmittance was measured in visible and near infrared region and found to be 54% transmittance for Y2O3 doped Si3N4 ceramics. β- phase transformation was suppressed with REO addition. High hardness and high fracture toughness were achieved by addition of REO. Adding REO shows good mechanical properties as high strength and toughness. Coefficient of friction of the REO doped silicon nitride ceramics was lower than that of without REO doped silicon nitride ceramics.
The MoxV3−xO7/MWNTs nanocomposites were fabricated via a hydrothermal reaction followed by self-assembling process. The nanocomposites were characterized in terms of surface morphology and structure by FESEM, TEM, XRD...
The MoxV3−xO7/MWNTs nanocomposites were fabricated via a hydrothermal reaction followed by self-assembling process. The nanocomposites were characterized in terms of surface morphology and structure by FESEM, TEM, XRD and XPS analysis, respectively. The electrochemical behaviors of the nanocomposites were investigated by galvanostatic charge-discharge test and cyclic voltammetry. The results showed that MoxV3−xO7/MWNTs nanocomposites had great cycleability as well as capacity characteristics, which was 277.4 mAh/g in the first discharge process and remained 207.9 mAh/g after fiftieth discharge cycle. In the rapid charge-discharge test, the capacity rate still remained 88.6 % after twentieth cycles at 1.2 C discharge.
Novel CoCrFeNiTiAlx(x:molar ratio, other elements are equimolar) high-entropy alloys were prepared by vacuum arc melting and these alloys were subsequently annealed at 1000 °C for 2 h. The annealing effects on st...
Novel CoCrFeNiTiAlx(x:molar ratio, other elements are equimolar) high-entropy alloys were prepared by vacuum arc melting and these alloys were subsequently annealed at 1000 °C for 2 h. The annealing effects on structure and mechanical properties were investigated. Compared with the as-cast alloys, there are many complex intermetallic phases precipitated from the solid solution matrix in the as-annealed alloys with Al content lower than Al1.0. Only simple BCC solid solution structure appears in the as-annealed Al1.5 and Al2.0 alloys. This kind of alloys exhibit high resistance to anneal softening. Most as-annealed alloys possess even higher Visker hardness than the as-cast ones. The as-annealed Al0.5 alloys shows the highest compressive strength while the Al0 alloy exhibits the best ductility, which is about 2.6 GPa and 13%, respectively. The CoCrFeNiTiAlx high-entropy alloys possess integrated high temperature mechanical property as well.
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