In the present paper, magnesium dititanate (MgTi2O5, M2T) was introduced into aluminum titanate (Al2TiO5, AT) to form AT-M2T solid solution so that the thermal shock resistance of Al 2TiO5 could be kept still good whi...
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In the present paper, magnesium dititanate (MgTi2O5, M2T) was introduced into aluminum titanate (Al2TiO5, AT) to form AT-M2T solid solution so that the thermal shock resistance of Al 2TiO5 could be kept still good while without any decomposition. The effect of MgTi2O5 addition on thermal shock resistance of Al2TiO5 was investigated. The experimental results showed that the thermal shock resistance of Al 2TiO5 began to decrease when a little amount of MgTi 2O5 was added and then rose with the continuous addition of MgTi2O5, even overrunning that of pure Al 2TiO5 when 30mol% MgTi2O5 was contained. It was found that fine solid solution was formed between Al 2TiO5 and MgTi2O5, which enhanced the thermal shock resistance of Al2TiO5.
Highly oriented plate-like rod/tube arrays of ZnO arc synthesized by a solution-based approach at low temperature. The ZnO rod/tube arrays grow oriented vertically on silicon substrate and the intersectant ZnO nanoshe...
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Calcium carbonate particles with different morphologies were fabricated by the precipitation reaction of sodium carbonate with calcium chloride in the absence and presence of the copolymer poly (styrene-alt-maleic aci...
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Calcium carbonate particles with different morphologies were fabricated by the precipitation reaction of sodium carbonate with calcium chloride in the absence and presence of the copolymer poly (styrene-alt-maleic acid) (PSMA) at 80°C, respectively. The as-prepared products were characterized with SEM, XRD, Infrared and BET surface areas. The results showed that the pH of solution and the concentration of PSMA and CaCO3 significantly influenced the morphologies of CaCO3 particles. Various crystal morphologies of calcium carbonate, such as plates, rhombohedras, rods, ellipsoids, dumbbells, peanuts, spheres etc., could be obtained depending on the experimental conditions.
As has been discussed, research on the electronic structure between organic and inorganic atoms in hybrid compounds has become important. In our study, DV—Xα method was employed to calculate the electronic structure...
As has been discussed, research on the electronic structure between organic and inorganic atoms in hybrid compounds has become important. In our study, DV—Xα method was employed to calculate the electronic structure of the hybrid compound. The information obtained from the calculation included orbit charge, bonding order, Fermi energy, density of the state, etc. The influence of organic and inorganic parts on the energy band structure of the hybrid compound was discussed based on the calculation results of Fermi energy and density of state. The chemical bonding between organic and inorganic parts in the hybrid compound was also analyzed in detail according to the orbital charges and bond orders.
A hydrocarbon proton exchange membrane, the sulfonated styrene/butylene-ethylene/styrene (s-SEBS) three blocks copolymer membrane was prepared. The performance and microstructure of membranes were investigated. The su...
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A hydrocarbon proton exchange membrane, the sulfonated styrene/butylene-ethylene/styrene (s-SEBS) three blocks copolymer membrane was prepared. The performance and microstructure of membranes were investigated. The sulfonic groups determined by a FT-IR were on the parapositions of phenyls of PS blocks. The conductivity, water uptake, swelling and hydration coefficient all increase drastically when sulfonation degree came to 15 percent, which exhibited the percolation threshold. Then the first three kept slow increasing with the sulfonation degree growing, but the hydration coefficient came to the peak when the sulfonation degree was about 20. AFM showed that suffocated PS phases were the cylinder structure with 20-30 nm.
With the preparation of organic-inorganic layered perovskite-type compounds (C4H9NH3)2MCl4 (M = Mn, Cu) in solutions, X-ray diffraction (XRD), scanning electron microscopy (SEM),thermal gravimetry (TG) and differentia...
With the preparation of organic-inorganic layered perovskite-type compounds (C4H9NH3)2MCl4 (M = Mn, Cu) in solutions, X-ray diffraction (XRD), scanning electron microscopy (SEM),thermal gravimetry (TG) and differential scanning calorimetry (DSC) have been used to characterize the obtained powders. XRD patterns demonstrate that the two compounds have obvious layered structures and SEM pictures reveal that both (C4H9NH3)2MCl4 and (C4H9NH3)2CuCl4 take on obvious sheet-like microstructure. TG&DSC curves indicate that (C4H9NH3)2CuCl4 decomposes at much lower temperature than (C4H9NH3)*** is ascribed to weakening interactions between its organic and inorganic components, which is presumably due to the Jahn-Teller distortion of [CuCl6] octahedra.
The Small Punch Creep Tests (SP-C tests) are simulated by a Finite Element Method (FEM). The objective of the present study is to establish a foundation for the SP-C test method by investigating the deformation and st...
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The Small Punch Creep Tests (SP-C tests) are simulated by a Finite Element Method (FEM). The objective of the present study is to establish a foundation for the SP-C test method by investigating the deformation and stress state of the SP-C test specimen. The emphasis is placed on the dependence relation of the creep strain and the stress on the measurable quantities, such as applied loads and the central deflections. Simulation works are conducted for two different materials, one is the tungsten-alloyed 9% Cr ferritic steel and the other is 12Cr1MoV steel. The numerical results for the central deflection versus time curves are quantitatively similar to the experimental results obtained on tungsten-alloyed 9% Cr ferritic steels. From the numerical results, the relationship between the central deflection and the equivalent creep strain is approximately independent of load, temperature, and material properties. The magnitude of the equivalent stress in the central region of the SP-C specimen shows no significant change with respect to time at the secondary creep stage, an approximate equation is proposed for the assessment of the equivalent stress in the SP-C specimen. As a farther result, the high temperature creep properties of the 12Cr1MoV steel and tungsten-alloyed 9% Cr ferritic steel are appraised by numerical simulation. The results are in good agreement with the results from the standard test method. The results indicate that the small punch test technique is an effective method for the evaluation of the high-temperature creep properties of materials.
The numerical simulation for the Small Punch creep (SP-C) tests is conducted using a Finite Element method. The objective of the present study is to obtain the deformation states of the SP-C specimen and to estimate t...
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ISBN:
(纸本)0878499709
The numerical simulation for the Small Punch creep (SP-C) tests is conducted using a Finite Element method. The objective of the present study is to obtain the deformation states of the SP-C specimen and to estimate the feasibility of SP-C test method for high-temperature creep properties. The emphasis is put on the relationship between the equivalent creep strain and the central deflection of the SP-C specimen. The time history of central deflection and equivalent creep strain is obtained by finite element method and the effects of the load, temperature and material properties on the relationship of central deflection and equivalent creep strain are discussed. From the numerical results, the relationship between the central deflection and the equivalent creep strain is approximately independent of load, temperature, and material properties. As a farther result, the high temperature creep properties of the 12CrlMoV steel are appraised by numerical simulation. The results are in good agreement with the results from the standard test method. The results indicate that the small punch test technique is an effective method for the evaluation of the high-temperature creep properties of materials.
TiO2 thin films were prepared on soda lime glass, fused quartz and stainless steel substrates by liquid phase deposition (LPD) method from a (NH4)2TiF6 aqueous solution upon the addition of boric acid (H3BO3), and the...
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TiO2 thin films were prepared on soda lime glass, fused quartz and stainless steel substrates by liquid phase deposition (LPD) method from a (NH4)2TiF6 aqueous solution upon the addition of boric acid (H3BO3), and then calcined at 500°C for 2 h. The prepared films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It was found that the substrates obviously influenced the element composition and microstructure of TiO2 thin films. Except Ti, O and a small amount of F and N elements, which came from the precursor solution, some Si (or Fe) element in the thin films deposited on soda lime glass and quartz substrates (or on stainless steel substrate) was confirmed. The Si (or Fe) element in the thin films could be attributed to two sources. One was from the SiF 62- ions (or FeF62- ions) formed by a reaction between the treatment solution and soda lime glass or quartz (or stainless steel) substrates. The other was attributed to the diffusion of Si (or Fe) from the surface of substrates into the TiO2 thin films after calcination at 500°C. The Si (or Fe) element in the TiO2 thin films could behave as a dopant and resulted in the formation of composite SiO2/TiO2 (or Fe2O3/TiO2) thin films on the substrates.
In liquid composites molding (LCM) processes,a gap between the perform and the mold edge can create a preferential flow path for the resin, which is the so-called edge effect. The resin flow behaviors in different gap...
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In liquid composites molding (LCM) processes,a gap between the perform and the mold edge can create a preferential flow path for the resin, which is the so-called edge effect. The resin flow behaviors in different gaps were studied by the unidirectional flow method together with the equivalent permeability tensor of flow path computed by two geometric models. In addition, the filling process was simulated to predict the influences of edge effects on the flow pattern. It is found out that even small gaps would disturb the edge flow. The simulation shows good agreement with the experiments.
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