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排序方式: 共有113条查询结果,搜索用时 31 毫秒
1.
T. Peprnicek A. Kalendova J. Simonik J.F. Gerard 《Polymer Degradation and Stability》2006,91(12):3322-3329
The paper concentrates on poly(vinyl chloride) - PVC - from the point of nanocomposite characterisation through thermal degradation of samples, evolution of the changes caused by elevating temperature using TGA, FTIR and Congo Red methods combined with morphological characterisation by XRD and TEM analyses. A novel method of PVC-paste/nanocomposite preparation while processing was used. During preparation, PVC plasticizer was mixed with clay, both natural and organophilic, and the suspension was then compounded with the other components. Two factors were followed: effect of shearing alone, and in combination with temperature. As is presented, the type of nano-filler and its chemical modifier have obvious influence on final properties either thermal or morphological. Presented contribution follows previous part of investigation and brings further information from PVC-paste/nanocomposite field. 相似文献
2.
Koichi Kikuta Koji Noda Shin Okumura Toshiaki Yamaguchi Shin-ichi Hirano 《Journal of Sol-Gel Science and Technology》2007,42(3):381-387
Orientation control of perovskite compounds was investigated by the application of a seed layer prepared from oxide nanosheets.
An aqueous suspension of oxide nanosheets was prepared by the exfoliation of a layered compound of KCa2Nb3O10 oxide grains. A seed layer composed of (TBA)Ca2Nb3O10 nanosheets (TBA = tetrabutylammonium) was formed on a glass substrate by simply dip coating it in the suspension. Two kinds
of perovskite compounds, LaNiO3 (LNO) and Pb(Zr,Ti)O3 (PZT) with a preferred orientation of (00l) were successfully grown on this seeded glass substrate. In this study, the relation between lattice mismatch and electrical
properties is investigated. A large, oriented PZT film with a size of 5 ×4 cm shows an improved P-E hysteresis behavior by
use of this orientation control. 相似文献
3.
4.
Liping Kang Gaini Zhang Yunlong Bai Huanjing Wang Zhibin Lei Zonghuai Liu 《物理化学学报》2020,36(2):1905032-0
功率密度高、倍率性能优异和循环性能好等特性使得超级电容器在储能领域显示了巨大的应用前景。尽管二维层状材料剥离形成的纳米片层不仅可为电化学反应提供独特的纳米级反应空间,而且由其组装的层状纳米电极材料具有化学和结构上的氧化还原可逆性及纳米片层水平方向上离子或电子快速传输通道。但是,纳米片层组装电极材料在纳米片层垂直方向上离子或电子传输存在障碍,对于超级电容器功率密度和能量密度的提高及实现快速能量储存非常不利。因此,如何通过改善离子或电子的快速传输,实现超级电容器大功率密度下的高能量密度是超级电容器电极材料发展的方向之一。本文主要综述了二维层状材料剥离成纳米片层,纳米片层孔洞化策略及组装孔洞化材料在超级电容器电极材料中的应用。纳米层孔洞化技术是改善层状电极材料在纳米片层垂直方向离子或电子传输的有效手段,为实现高比电容下的高倍率性能超级电容器电极材料制备提供了方法学。最后,对开发大功率密度下的高能量密度超级电容器电极材料提出了展望。 相似文献
5.
Textile reinforce cements (TRC) are innovative materials that are used for repair of existing structures or recently as stand-alone lightweight structural members. Fracture and thermal behavior of these materials are very complicated due to multiple failure modes. The undergoing processes cannot be described by the simple constitutive equation. In this perspective the contribution of monitoring techniques is crucial. Acoustic emission (AE) is used to check the behavior of TRC beams and plates in different states of structural health: intact, thermally pre-cracked and self-healed by polymer powder. This is the first time that the AE behaviors of intact, cracked and self-healed TRC laminates are compared in literature. 相似文献
6.
Herein, a new 2-dimensional coordination polymer based on copper (II), {Cu2(L)(DMF)2}n, where L stands for 1,2,4,5-benzenetetracarboxylate (complex 1) is synthesized. Interestingly, we demonstrate that both solvent and sonication are relevant in the top-down fabrication of nanostructures. Water molecules are intercalated in suspended crystals of complex 1 modifying not only the coordination sphere of Cu(II) ions but also the final chemical formula and crystalline structure obtaining {[Cu(L)(H2O)3]·H2O}n (complex 2). On the other hand, ultrasound is required to induce the nanostructuration. Remarkably, different morphologies are obtained using different solvents and interconversion from one morphology to another seems to occur upon solvent exchange. Both complexes 1 and 2, as well as the corresponding nanostructures, have been fully characterized by different means such as infrared spectroscopy, x-ray diffraction and microscopy. 相似文献
7.
Friction and wear behaviors of graphite-like carbon (GLC) films in aqueous environment were investigated by a reciprocating sliding tribo-meter with ball-on-disc contact. Film structures and wear scars were studied by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and a non-contact 3D surface profiler. A comprehensive wear model of the GLC film in aqueous environment was established, and two feasible approaches to control critical factor to the corresponding wear failure were discussed. Results showed that wear loss of GLC films in aqueous environment was characterized by micro-plough and local delamination. Due to the significant material loss, local delamination of films was critical to wear failure of GLC film in aqueous environment if the film was not prepared properly. The initiation and propagation of micro-cracks within whole films closely related to the occurrence of the films delamination from the interface between interlayer and substrate. The increase of film density by adjusting the deposition condition would significantly reduce the film delamination from substrate, meanwhile, fabricating a proper interlayer between substrate and GLC films to prevent the penetration of water molecules into the interface between interlayer and substrate could effectively eliminate the delamination. 相似文献
8.
Real-time visualisation of deformation fields using speckle interferometry and temporal phase unwrapping 总被引:1,自引:0,他引:1
A real-time system for analysing data from speckle interferometers, and speckle shearing interferometers, has been developed. Interferograms are continuously recorded by a digital camera at a rate of 60 frames s−1 with temporal phase shifting carried out at the same rate. The images are analysed using a pipeline image processor. With a standard 4-frame phase-shifting algorithm (phase steps of π/2), wrapped phase maps are calculated and displayed at 15 frames s−1. These are unwrapped using a temporal phase unwrapping algorithm to provide a real-time colour-coded display of the relevant displacement component. Each camera pixel (or cluster of pixels) behaves in effect as an independent displacement sensor. The reference speckle interferogram is updated automatically at regular user-defined intervals, allowing arbitrarily large deformations to be measured and errors due to speckle decorrelation to be minimised. The system has been applied to the problem of detecting sub-surface delamination cracks in carbon fibre composite panels. 相似文献
9.
The effect of transverse shear on delamination in layered, isotropic, linear-elastic materials has been determined. In contrast to the effects of an axial load or a bending moment on the energy-release rate for delamination, the effects of shear depend on the details of the deformation in the crack-tip region. It therefore does not appear to be possible to deduce rigorous expressions for the shear component of the energy-release rate based on steady-state energy arguments or on any type of modified beam theory. The expressions for the shear component of the energy-release rate presented in this work have been obtained using finite-element approaches. By combining these results with earlier expressions for the bending-moment and axial-force components of the energy-release rates, the framework for analyzing delamination in this type of geometry has been extended to the completely general case of any arbitrary loading. The relationship between the effects of shear and other fracture phenomena such as crack-tip rotations, elastic foundations and cohesive zones are discussed in the final sections of this paper. 相似文献
10.
Nikolaos A. Chrysochoidis Dimitris A. Saravanos 《International Journal of Solids and Structures》2007,44(25-26):8751-8768
A coupled linear layerwise laminate theory and a beam FE are formulated for analyzing delaminated composite beams with piezoactuators and sensors. The model assumes zig-zag fields for the axial displacements and the electric potential and it treats the discontinuities in the displacement fields due to the delaminations as additional degrees of freedom. The formulation naturally includes the excitation of piezoelectric actuators, their interactions with the composite laminate, and the effect of delamination on the predicted sensory voltage. The quasistatic and modal response of laminated composite Gr/Epoxy beams with active or sensory layers having various delamination sizes is predicted. The numerical results illustrate the strong effect of delamination on the sensor voltage, on through the thickness displacement and on the stress fields. Finally, the effect of delamination on modal frequencies and shapes are predicted and compared with previously obtained experimental results. 相似文献