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.
Polycrystalline PbTe samples have been implanted by Sn+ ion at 200KeV with doses of 6×1016 and 1×1017 ions/cm2 in order to create a modified Pb1-xSnxTe layers with gradation of carrier concentration. The ele...
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Polycrystalline PbTe samples have been implanted by Sn+ ion at 200KeV with doses of 6×1016 and 1×1017 ions/cm2 in order to create a modified Pb1-xSnxTe layers with gradation of carrier concentration. The electrical conductivity, Hall coefficient and thermoelectric power measurements have been carried out at 300K on the implanted samples. The effect of Sn+ ion implantation on structure of PbTe has been investigated using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS). The results indicate the possible presence of Pb1-xSnxTe(x=0.2 approx. 0.25) phase during the ion-implantation processes.
PbTe is a useful thermoelectric material for the design of functionally graded materials (FGM) thermoelectric device. Since the maximum figure of merit shifts in a wide temperature range depending upon carrier concent...
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PbTe is a useful thermoelectric material for the design of functionally graded materials (FGM) thermoelectric device. Since the maximum figure of merit shifts in a wide temperature range depending upon carrier concentration, the stepwise carrier concentration FGM of PbTe is expected to attain high efficiency of thermoelectric energy conversion. In order to improve the carrier concentration profile, 110 KeV Zn+ ions were implanted into n-type PbTe samples. X-ray diffraction (XRD) has been used to examine the effect of ions implantation on the structure of PbTe. By varying the ion dose it is possible to investigate the Zn-PbTe phase relationship, and the effect of forming a joint boundary on the thermoelectric properties of PbTe. Electrical resistance and Hall coefficient measurements have also been carried out as a function of implantation dose at room temperature.
Sn+ ions were implanted into n-type lead telluride with doses of 6×1016 and 1×1017 ions/cm2 at an energy of 200 KeV. The thermoelectric properties of temperature dependence of the implanted and the unimplant...
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Sn+ ions were implanted into n-type lead telluride with doses of 6×1016 and 1×1017 ions/cm2 at an energy of 200 KeV. The thermoelectric properties of temperature dependence of the implanted and the unimplanted samples after annealing were investigated. Thermoelectric figure of merit was calculated using the measured data. It has been found that Sn+ ion implantation can form a two layered FGM with stepwise carrier concentration, and modify the thermoelectric properties of n-type PbTe.
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.
The grain-boundary resistance of ZrO2 mainly consists of the contribution from the space-charge layers Rsc and that from the grain-boundary phase Rgbp The reduction of Rsc can be realized by the segregations of solute...
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The grain-boundary resistance of ZrO2 mainly consists of the contribution from the space-charge layers Rsc and that from the grain-boundary phase Rgbp The reduction of Rsc can be realized by the segregations of solutes with positive effective charge in the space-charge layers,while the reduction of Rgbp can be achieved by decreasing the amount of the grain-boundary phase,changing the morphology of the phase and forming grain-boundary phase with high *** best grain-boundary design effect can only be achieved by the joint design of the space-charge layers and the grain-boundary phase.
Solid-state sintering of oxides involves a diffusion process of point defects. Some sintering models based on diffusion have been proposed. However, the application of these models needs a knowledge of the defect stru...
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Solid-state sintering of oxides involves a diffusion process of point defects. Some sintering models based on diffusion have been proposed. However, the application of these models needs a knowledge of the defect structure of oxides. The positron annihilation technique (PAT) is a suitable tool to study the solid-state sintering processes of oxides. The PAT study of the solid-state sintering of YS7 indicates that the cation interstitial diffusion plays an important role in the sintering.
According to a space-charge theory analysis, the space-charge potential of YSZ is negative, which corresponds to a V-0(..) depletion in the space-charge layer. An extremely low grain-boundary conductivity of the high-...
According to a space-charge theory analysis, the space-charge potential of YSZ is negative, which corresponds to a V-0(..) depletion in the space-charge layer. An extremely low grain-boundary conductivity of the high-purity YSZ is thus explained. Under the condition that the bulk property is ensured by the optimal dopant additions, an idea of increasing the grain-boundary conductivity by the segregations of solutes with positive effective charge is put forward. The most likely driving force for the segregations is the elastic strain energy. And the feasibility of this idea has been proved by some experimental and theoretical results.
A new destabilization phenomenon of fully-stabilized ZrO2 (FSZ) is studied by x-ray diffraction. The study has proved that H3BO3 can produce very severe destabilization in FSZ when heated at temperature higher than 80...
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A new destabilization phenomenon of fully-stabilized ZrO2 (FSZ) is studied by x-ray diffraction. The study has proved that H3BO3 can produce very severe destabilization in FSZ when heated at temperature higher than 800°C. The destabilization is summarized by two reactions.
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