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1.
The main aim of this work is dual computer analysis of probabilistic coefficients for the homogenized tensor of the polymer filled with the rubber particles having randomized Poisson ratios of both constituents. The major issue is to verify an influence of a randomness in rubber Poisson ratio close to the compressibility limit on the uncertainty of the effective tensor probabilistic characteristics. Probabilistic analysis presented here is carried out using mainly the stochastic perturbation technique provided by the common application of the traditional FEM commercial code ABAQUS and the symbolic computations package MAPLE. This FEM-based technique employs polynomial response function of the optimum order recovered from the weighted least squares method and following a set of deterministic solutions obtained for various values of the randomized input parameter. Optimization procedure is released entirely into a symbolic environment, where maximization of the correlation factor together with minimization of the fitting variance and approximation error are applied. Homogenization technique consists in equating of deformation energies for the real composite and the artificial one characterized by the effective elasticity tensor with uncertainty. 相似文献
2.
We compare the current density–voltage (J–V) and magnetoconductance (MC) response of a poly(3-hexyl-thiophene) (P3HT) device (Au/P3HT(350 nm)/Al) before and after annealing above the glass transition temperature of 150 °C under vacuum. There is a decrease of more than 3 orders of magnitude in current density due to an increase of the charge injection barriers after de-doping through annealing. An increase, approaching 1 order of magnitude, in the negative MC response after annealing can be explained by a shift in the Fermi level due to de-doping, according to the bipolaron mechanism. We successfully tune the charge injection barrier through re-doping by photo-oxidation. This leads to the charge injection and transport transitioning from unipolar to ambipolar, as the bias increases, and we model the MC response using a combination of bipolaron and triplet-polaron interaction mechanisms. 相似文献
3.
《Journal of the European Ceramic Society》2005,25(2-3):271-276
Ceramers were prepared by using commercially available polymethyl- and polymethylphenylsiloxanes as starting materials and converting them by pyrolysis in a nitrogen atmosphere to a hybrid state called ceramer. The microstructures were modified by adding prepyrolized polymethylsiloxanes as filler or by using a blowing agent to fabricate foamed ceramers. The porosity characteristics were quantitatively evaluated using nitrogen adsorption whereas the hydrocarbon sorption behaviour was investigated by adsorption and desorption processes via thermogravimetry. For comparison commercial activated carbons, which are especially designed for hydrocarbon adsorption, were characterized in the same way. It turns out that the new ceramer adsorbents can be used as alternative material for activated carbon. Moreover, they show a significant advantage against activated carbon as the adsorbed species can be easily released, e.g. by heating. Therefore, the ceramers are especially suitable for cyclic ad- and desorption processes as it is necessary for storage or purification applications. 相似文献
4.
《Materials Letters》2007,61(11-12):2164-2166
By radiating a linear polyethylenimine–HAuCl4 aqueous solution with natural sunlight, we obtained polyelectrolyte-protected gold nanoparticles, and the size of such gold nanoparticles can be controlled by varying the molar ratio of polyelectrolyte to gold. 相似文献
5.
《Materials Letters》2007,61(11-12):2191-2194
Porous TiO2 films with both mesoporosity and macroporosity were fabricated by a templated sol–gel method for applications, such as dye-sensitized solar cells (DSC), photocatalysis and catalysis. With the incorporation of differently sized pores, the resultant structures exhibit high surface areas and possess interpenetrating aligned pore channels, which are believed to be beneficial for applications where diffusion of reactants to interior surface can be rate limiting. Both liquid and solid TiO2 precursors can be applied for large area coating in this process. Almost crack-free films were produced by templated coating of pre-synthesized TiO2 nanoparticles. The measured specific surface area and porosity of synthesized films were in the range of 33–137 m2/g and 61–80%, respectively, depending on the size of the selected template. 相似文献
6.
《Materials Letters》2006,60(25-26):3088-3090
In this paper, we doped p-type conductivity dehydrated nanotubed titanic acid (DNTA) into insulator polymer poly(methyl methacrylate) (PMMA). The electric properties of this nanocomposite were investigated. The photoluminescence efficiency of fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) in PMMA matrix was enhanced by doping with DNTA. Moreover, screen effect by DNTA with high permittivity caused the emission from DCJTB to be blue-shifted. 相似文献
7.
《Sensors and actuators. B, Chemical》2006,113(1):94-99
Cross-linked polymers made of methyl methacrylate (MMA) as a monomer and divinylbenzene (DVB) as a cross-linking agent were prepared in the presence of toluene or p-xylene as a solvent. The cross-linked polymer prepared in toluene tended to sorb toluene vapor preferably, while the cross-linked polymer prepared in p-xylene sorbed p-xylene vapor preferably. The observed molecular recognition ability can be explained on the bases of an imprinting effect by solvent molecules. Molecularly imprinted polymer (MIP) powders were blended with PMMA, and the blended films were coated on a piezoelectric quartz crystal with a view to preparing QCM-based VOC sensors. The imprint effect was clearly observed, even in these blended films. The response of the sensor towards toluene or p-xylene vapor was reversible; however, the response time was slow due to the existence of the matrix polymer around the MIP particles. 相似文献
8.
V. Geros M. Santamouris S. Amourgis S. Medved E. Milford G. Robinson K. Steemers S. Karatasou 《Renewable Energy》2006,31(15):2447-2459
The present paper aims to present a distant-learning training module that concerns the environmental design of urban buildings. The whole approach attempts to integrate topics that concern the design of urban buildings from various points of views, e.g. active and passive systems, automation systems, indoor air quality, economic aspects, energy and resources management. The package offers both printed and electronic material that gives the possibility to the students to study the various topics by using different educational methods. Additionally, the present package contains software tools that permit the students to examine real or hypothetical situations and to study further the influence of various parameters that concern the environmental building design. 相似文献
9.
《Materials Letters》2007,61(14-15):3059-3063
In order to explore the tribological potential of the dual phase (DP) steel as a wear resistant material, the wear characteristics of the dual phase (DP) steel have been investigated with varying amounts of martensite from 43 to 81 vol pct, developed by varying holding time at the intercritical annealing temperature of 780 °C. Dry sliding wear tests have been conducted on DP steels using a pin-on-disk machine under different normal loads of 61.3, 68.5, 75.7 and 82.6 N and at a constant sliding speed of 1.20 m/s. At these loads, the mechanism of wear is mainly delamination, which has been confirmed by SEM micrographs of the subsurface and wear debris of the samples. Wear and friction properties have been found to be improved with increasing martensite volume fraction in dual phase steels. 相似文献
10.
《Organic Electronics》2007,8(4):311-316
We report the electrical characterization of hybrid permeable-base transistors with tris(8-hydroxyquinoline) aluminum as emitter layer. These transistors were constructed presenting an Al/n-Si/Au/Alq3/V2O5/Al structure. We investigate the influence of the V2O5 layer thickness and demonstrate that these devices present high common-base and common-emitter current gain, and can be operated at very low driving voltages, lower than 1 V, in both, common-base and common-emitter modes. 相似文献