Al/Al2O3 composites of different ratios were hot-press sintered at 575～640℃ under a pressure of 30 MPa for 2 h in a vacuum furnace. It was found that the relative density of the Al/Al2O3composites could be increased...
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Al/Al2O3 composites of different ratios were hot-press sintered at 575～640℃ under a pressure of 30 MPa for 2 h in a vacuum furnace. It was found that the relative density of the Al/Al2O3composites could be increased evidently with the rise of sinter temperature. No reaction occurred between Al and Al2O3 at the sinter temperatures. Under 640℃-30 MPa-2 h experimental condition, Al/Al2O3 system FGM was successfully fabricated, and its density range changed quasi-continuously from 2.887x103 kg/m3 to 3.1909x103 kg/m3 within the middle 1.0 mmthickness range.
(PEO)xMoO3·nH2O(x=0～2) nanocomposite films were prepared by ion exchange method and polymer solution direct intercalation in sol-gel route. The synthesis and structure of the films were investigated by XRD, DSC,...
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(PEO)xMoO3·nH2O(x=0～2) nanocomposite films were prepared by ion exchange method and polymer solution direct intercalation in sol-gel route. The synthesis and structure of the films were investigated by XRD, DSC, FTIR, etc. The results show that MoO3 xerogel has a layered structure, which arranges in b-direction. The interlayer distance of MoO3 xerogel increases from 0.690 nm at x=0 to 1.308 nm at x=2 after heat treatment. PEO can be completely intercalated into the interlayer at x=0.5～1 and has strong interaction with MoO3 host.
The dislocation structure in magnetron sputtered c-textured YBCO films deposited on (100)SrTiO3 substrates consists of vertical (//c axis) screw dislocation forests together with layered horizontal (|caxis) edge dislo...
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The dislocation structure in magnetron sputtered c-textured YBCO films deposited on (100)SrTiO3 substrates consists of vertical (//c axis) screw dislocation forests together with layered horizontal (|caxis) edge dislocation net-works. It is found that in the oxygenation process in YBCO films, oxygen diffusion is enhanced greatly by the short circuit paths which we suggest to be the horizontally ( c axis) layered edge dislocation net-works. Diffusion equation for oxygenation was solved with the help of Fishers theory of grain boundary diffusion, and an active energy 1.16 ev.``
Filled skutterudite NaFe/sub 4/P/sub 12/ single crystal nanowires were synthesized by using a hydrothermal-reduction-alloying method. X-ray diffraction (XRD), Electron diffraction (ED), Raman scattering, as well as el...
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Filled skutterudite NaFe/sub 4/P/sub 12/ single crystal nanowires were synthesized by using a hydrothermal-reduction-alloying method. X-ray diffraction (XRD), Electron diffraction (ED), Raman scattering, as well as elemental analysis were used to characterize the product. High-resolution transmission electron microscope (HRTEM) was used to investigate the microstructure of the nanowire. A growth mechanism of NaFe/sub 4/P/sub 12/ nanowire was proposed.
Polyaniline/NaFe/sub 4/P/sub 12/ whiskers and polyaniline/NaFe/sub 4/P/sub 12/ nanowire composites were prepared by an in situ compounding method. X-ray diffraction (XRD), infrared spectra, thermal gravity analysis (T...
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Polyaniline/NaFe/sub 4/P/sub 12/ whiskers and polyaniline/NaFe/sub 4/P/sub 12/ nanowire composites were prepared by an in situ compounding method. X-ray diffraction (XRD), infrared spectra, thermal gravity analysis (TGA) transmission electron microscope (TEM) and electron diffraction (ED) were used to characterize polyaniline and the composites. Polyaniline can grow on the surface of NaFe/sub 4/P/sub 12/ whisker and forms a novel "brush" structure. The mechanism of the forming of the "brush" structure is suggested. The conductivity and Seebeck coefficient of polyaniline and the composites were measured.
Several skutterudite antimonides filled with atoms of different kinds, (Ba, M)/sub y/Co/sub 4/Sb/sub 12/ (M=Ce, La, Sr), have been synthesized by the combination of solid state reaction and melting methods. Thermal co...
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Several skutterudite antimonides filled with atoms of different kinds, (Ba, M)/sub y/Co/sub 4/Sb/sub 12/ (M=Ce, La, Sr), have been synthesized by the combination of solid state reaction and melting methods. Thermal conductivity of (Ba,Sr)/sub y/Co/sub 4/Sb/sub 12/ samples shows a behavior similar to that of Ba/sub y/Co/sub 4/Sb/sub 12/. Adding a small amount of Ce or La to the Ba/sub y/Co/sub 4/Sb/sub 12/ system is effective in further reducing the lattice thermal conductivity. The difference in the ionic radii of the two co-filler atoms is the most sensitive factor for scattering of phonons. The multi-filled (Ba, M)/sub y/Co/sub 4/Sb/sub 12/ (M=Sr, Ce, La) show lower Seebeck coefficients as compared to the single-filled Ba/sub y/Co/sub 4/Sb/sub 12/ having the same total filling fraction. It is expected that higher thermoelectric performance could be realized by further optimization of the composition of filler species.
The synthesis of filled skutterudite compounds (Ce or Y)_y(Fe)_x(Co)_(4x)(Sb)_(12), through a solidstate reaction using chloride of Ce or Y,high purity powder of Co, Fe, and Sb as starting materials,was investigated. ...
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The synthesis of filled skutterudite compounds (Ce or Y)_y(Fe)_x(Co)_(4x)(Sb)_(12), through a solidstate reaction using chloride of Ce or Y,high purity powder of Co, Fe, and Sb as starting materials,was investigated. (Ce or Y)_y(Fe)_x(Co)_(4x)(Sb)_(12) (x=0--1.0, y=0--0.15) compounds were obtained at850--1 123 K. The results of Rietveld analysis demonstrate that (Ce or Y)_y(Fe)_x(Co)_(4x)(Sb)_12synthesized by a solid state reaction possesses a filled skutterudite structure. The filling fraction ofCe or Y obtained by Rietveld analysis agrees well with the composition obtained by chemicalanalysis. The lattice constant of (Ce)_y(Fe)_x(Co)_(4x)(Sb)_(12) increases with increasing substitution of Fe at Cosites, and with an increasing Ce filling fraction in the Sb-dodecahedron voids. The lattice thermalconductivity of (Ce or Y)_y(Fe)_x(Co)_(4x)(Sb)_(12) decreases significantly with an increasing Ce or Y fillingfraction in the voids and with substitution of Fe at Co sites.
W-Mo system functionally graded material with density gradient, which can be applied to dynamic high-pressure technology, was prepared by hot-pressing at 1573K. In order to obtain fully dense body, suitable amount of ...
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W-Mo system functionally graded material with density gradient, which can be applied to dynamic high-pressure technology, was prepared by hot-pressing at 1573K. In order to obtain fully dense body, suitable amount of Ni and Cu was added. The FGM has quasi-continuous density variation in the thickness direction.
A subdynamics theory framework for describing multi coupled quantum computing systems is presented first. A general kinetic equation for the reduced system is given then, enabling a sufficient condition to be formula...
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A subdynamics theory framework for describing multi coupled quantum computing systems is presented first. A general kinetic equation for the reduced system is given then, enabling a sufficient condition to be formulated for constructing a pure coherent quantum computing system. This reveals that using multi coupled systems to perform quantum computing in Rigged Liouville Space opens the door to controlling or eliminating the intrinsic de coherence of quantum computing systems.
Up to 1.5 mol% Nb2O5 was added to 9 mol% Y2O3-stabilized ZrO2. According to an XRD analysis, the addition of Nb2O5 did not change the cubic structure of YSZ. As a result of the repulsion effect of the grain-boundary i...
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Up to 1.5 mol% Nb2O5 was added to 9 mol% Y2O3-stabilized ZrO2. According to an XRD analysis, the addition of Nb2O5 did not change the cubic structure of YSZ. As a result of the repulsion effect of the grain-boundary interface and the preferential segregation of Y2O3, the Nb2O5 segregation at the grain boundaries was not detected by EPMA. The resistances were measured by the complex impedance approach in air, Nb2O5 was found to increase the resistance per unit surface area of the grain boundaries. This result suggested that the most likely mechanism of the dissolution of Nb2O5 in YSZ should be Nb2O5 --> 2Nb(Zr) + 2e' + 4O(o)(x) + 1/2 O-2. Despite the Nb2O5 addition, the Arrhenius equation can still be applied to the resistances.
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