The texture of interfacial zone between cement paste and quartz in the cement-based composites containing polyvinyl alcohol (PVA), methylcellulose (MC) and their potyblend in an amount of 10 wt % with respect to cemen...
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The texture of interfacial zone between cement paste and quartz in the cement-based composites containing polyvinyl alcohol (PVA), methylcellulose (MC) and their potyblend in an amount of 10 wt % with respect to cement, as well as the texture of dehydrated bodies of PVA, MC, and the potyblend solutions, were investigated with SEM. The network texture of the dehydrated polyblend is confirmed by comparing the texture of dehydrated bodies of PVA and MC. The network texture has restrained the movement of polyblend molecules in the cement mortar but is helpful to forming a coherent interface between cement paste and quartz. The key factor of forming the coherent interface is not the neutralization reaction between H + from hydrolysis of quarts: and OH- from hydration of cement, but the electrostatic attraction and the chemical reaction between polar groups on the polyblend molecule and cations and onions from hydrolysis of quartz and hydration of cement, respectively. The model of the coherent interface formation is that excessive [HSiO3]- and [SiO3]2- onions are bonded with the hydrated cations such as Ca2+ and Al3+ , which is confirmed by the gel containing Ca and Si on the quartz surface.
By using such flier-plate material,quasi-isentropic compression can be *** on it,hypervelocity launching is further *** a result,an extremely high dynamic pressure can be obtained in lab.ratory,offering a practical me...
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By using such flier-plate material,quasi-isentropic compression can be *** on it,hypervelocity launching is further *** a result,an extremely high dynamic pressure can be obtained in lab.ratory,offering a practical method for the comprehensive determination of materials behavior,response,equation-of-state and properties in dynamic loading process.
The solid solutions of Al2(1.x)MgxTi 1+xO5 (x=0,0.01,0.05,0.1) were fabricated by the solid phase reaction method, and they were sintered under normal pressure. The thermal performance of Al2(1-x)MgxTi1+xO 5 was mainl...
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The solid solutions of Al2(1.x)MgxTi 1+xO5 (x=0,0.01,0.05,0.1) were fabricated by the solid phase reaction method, and they were sintered under normal pressure. The thermal performance of Al2(1-x)MgxTi1+xO 5 was mainly investigated. The results show that, the additive MgTi2O5 can not only restrain the decomposition of Al 2TiO5, but also greatly improve the densification of the solid solutions. With increasing mole percent of x, the thermal stability of Al2(1-x)MgxTi1+xO5 increases and the expansion coefficient decreases.
Preparation of a modified (Pb,Ca)TiO3 with (Zn1/2W1.2) (Ni1/2Nb1/2) substitution in B-site had been studied. Adding suitable amounts of MnCO3 in this modified PbTiO3 piezoelectric ceramics, the material performances c...
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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 ...
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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.
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.
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.
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.
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