The reflected coefficient of functionally graded layer to waves is very important as the design of impact-resistant FGMs. In the paper, the Optimization problem of propagation characteristic of elastic wave in FGM has...
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ISBN:
(纸本)0878499709
The reflected coefficient of functionally graded layer to waves is very important as the design of impact-resistant FGMs. In the paper, the Optimization problem of propagation characteristic of elastic wave in FGM has been investigated. The relation between the top layer's stress and displacement and the bottom layer's is deduced from elastic propagation equation as the incident wave is a plane and harmonic elastic stress wave, then the reflected coefficient of gradient layer is obtained, and the reflected coefficient is selected as object function of optimization. The thickness of each layer is selected as optimization design parameter. The conjugate gradient method is used to get the optimal results about gradient layers' thickness.
In the paper, firstly self-consistent model (SCM) is used for establishing the predicted formula which can predict the effective permittivity of the composite materials with core-shell type inclusions. Then the factor...
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ISBN:
(纸本)0878499709
In the paper, firstly self-consistent model (SCM) is used for establishing the predicted formula which can predict the effective permittivity of the composite materials with core-shell type inclusions. Then the factors on the effective permittivity of this kind of composite are investigated on the base of this predicted formula. The researching results indicate the effective permittivity of composite depends on not only the volume fraction of inclusions, but also the permittivity of matrix and inclusions (core and shell). According to our works, the optimal design of composite with core-shell type inclusion must be done if we want to make this composite get better effect of absorbing wave.
In the present study, Fe-Si sheets were formed by powder rolling of Fe-6.5wt%Si mixture powders, then were sintered in flowing Ar+5vol%H2 atmosphere. The changes in microstructure and density during the formation proc...
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In the present study, Fe-Si sheets were formed by powder rolling of Fe-6.5wt%Si mixture powders, then were sintered in flowing Ar+5vol%H2 atmosphere. The changes in microstructure and density during the formation process were mainly discussed. The results show that Fe-Si mixture powders can be rolled into comparatively compact sheets. During subsequent sintering and re-rolling, the density of the sheet gradually increased and Si diffused into Fe lattice step by step with the increasing of temperature.
In the paper, propagation of two-dimensional viscous-plastic waves in graded layer media is investigated by numerical method. Firstly, an infinite model is used to analysis wave's propagation in FGMs, this model h...
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ISBN:
(纸本)0878499709
In the paper, propagation of two-dimensional viscous-plastic waves in graded layer media is investigated by numerical method. Firstly, an infinite model is used to analysis wave's propagation in FGMs, this model has a finite gradient layer and non-reflecting boundary condition is used to simplify the model to be finite. Then the characteristic of viscous-plastic wave's propagation in graded media is investigated on the base of this model. The following contents is researched by this model: (1) The refracted effect of functionally gradient layers on incident wave;(2) the effect of incident angle on the bottom layer's stress;(3) the effect of gradient layer's thickness on the bottom layer's stress. Finally, some interesting, reasonable and important results are obtained by our researching work.
Among the preparing methods of ceramic particles reinforced metal matrix composites, the in-situ reaction synthesistechnology has many technical and economical advantages over other traditional methods obviously. Sev...
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Among the preparing methods of ceramic particles reinforced metal matrix composites, the in-situ reaction synthesistechnology has many technical and economical advantages over other traditional methods obviously. Several principal techniques to prepare metal matrix composites by in-situ reactive synthesis method were analyzed in this paper. Based on the analysis, a kind of preparing by using SHS and HP technique which was combustion and in-situ reaction synthesis of dual-phase ceramic reinforced copper-based composites was given. The impact of preparing condition on the structure and the behavior of the material were also researched. At last, some fundamental characteristics of the copper-based composite were studied, compared with the pure copper this kind of copper-based composite kept the electric conductivity and thermal conductivity above 80 percent, at the same time the wear resistance improved 6 times.
A new organic-inorganic hybrid compound （dienHs）2（P2Mo5O23） （1） [dien=NH（CH2CH2NH2）2] has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, thermogravimetric analysis, and t...
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A new organic-inorganic hybrid compound （dienHs）2（P2Mo5O23） （1） [dien=NH（CH2CH2NH2）2] has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, thermogravimetric analysis, and the single crystal X-ray diffraction technique. Compound 1 crystallizes in the triclinic system with space group P1 and a=0.9790（2） nm, b=0.9922（2） nm, c= 1.4644（3） nm, α=95.510（10）°, β=98.860（10）°, γ=95.700（10）°, V=1.3895（5） nm^3, Z=2, R=0.0465. The results show that the compound consists of dienH3^3＋＋ and P2Mo5O23^6-, and the heteropoly anion P2Mo5O23^6- is connected to a 1-D chain structure with the protonated dien by hydrogen bonds.
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.
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.
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.
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