Rare earth oxides/hydroxides are important emerging materials owing to their unique properties. Shape-controlled synthesis of elongated hexagonal bipyramid shaped La(OH)3 nanorods with different aspect ratios and trigram-shaped LaCO3OH nanosheets was systematically carried out by controlling the reaction conditions. Hydrazine and polyvinylpyrrolidone (PVP) surfactants used in synthesis are assumed to play a key “dual-template” role in determining the aspect ratio and shape of the resulting nanostructures. Elongated hexagonal bipyramid shaped La(OH)3 nanorods were found to grow along the preferred orientation [0001]. Six equivalent crystallographic facets, \((20\bar 20)\), \((02\bar 20)\), \((2\bar 200)\), \((0\bar 220)\), \((\bar 2200)\), and \((\bar 2020)\) lattice planes, were found to be exposed on the side surfaces on each nanorod as confirmed by combined transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED) analyses. A double-polarization phenomenon was found to occur at the nanorod surfaces by employing off-axis electron holography, implying that the material could be used as an effective dielectric microwave absorber. La(OH)3 nanorods with larger aspect ratios exhibit better absorption properties with respect to the maximum reflection loss and effective absorbing bandwidth. Thus, a novel method towards the reasonable design of bipyramid shaped La(OH)3 nanorods exhibiting tunable microwave absorption properties is proposed based on our synthesis strategy.
In the anodic processes of the iron electrode in both neutral and acidic solutions, general corrosion and pitting dynamical processes in the presence of chloride ions were observed in situ with the in-line digital holography. The dynamic processes such as formation and dissolution of the passive film, initiation and propagation of pitting have been studied. During the general corrosion, not only is the temporal structure in order, evidenced by the regular change of current with time, but also the spatial structure, indicated by the uniform fringes in the holograms at the electrode/electrolyte interface. However, during the pitting processes, the order of the spatial structure is destroyed, which is indicated by the wrinkled fringes in the holograms; the temporal order is broken as well evidenced by the irregular change of current with time. The experimental result shows that there is synergistic effect between H+ and Cl− on both the initiation stage and the propagation stage. With the presence of chloride ions, pitting occurs much more easily in acidic solution than in neutral solution. 相似文献
This paper reports the use of a real-time arithmetic image processor in an electro-optic holography system. A speckle interferometer is used to combine an image of an object, lit by laser light, with a mutually coherent reference beam. A CCD TV camera detects the interference pattern, and the phase of the reference beam is advanced by 90° between frames. An image is generated from each set of four sequential TV frames by subtracting alternate frames, squaring, and adding the two results. The result is improved picture quality compared with the use of binary pixels and compared with electronic speckle pattern interferometry. Experimental results are shown. 相似文献
The goal of the investigations was to measure the dynamics of photoinduced motions in semicrystalline polybutadiene backbone based polymer grafted with various degree of mesogenic thiols. We studied the influence of the grafting degree of the azobenzene-containing side groups and the length of terminal oxyaliphatic substituent in the side groups on the dynamics of the laser holographic volume and surface gratings recording. Measurements were performed in a typical laser degenerate two-wave mixing experiment, in which light self-diffraction efficiency during holographic recording was monitored. Mathematical model for grating formation based on coupling of three gratings has been assumed to elaborate the obtained results. Theoretical estimations and experimental results have shown very good agreement. 相似文献
Electron holography is a very powerful technique for mapping static electric and magnetic potentials down to atomic resolution. While electron holography is commonly considered synonymous with its off-axis variant in the high energy electron microscopy community, inline electron holography is widely applied in low-energy electron microscopy, where the realization of the off-axis setup is still an experimental challenge. This paper demonstrates that both inline and off-axis holography may be used to recover amplitude and phase shift of the very same object, in our example latex spheres of 90 and 200 nm in diameter, producing very similar results, provided the object does not charge under the electron beam. 相似文献
The properties of a photopolymerizable glass modified with high refractive index species incorporated at molecular level,
including a wide range of spatial frequencies and the recording kinetics, are analyzed. Implementation of emerging applications
is proposed.
The article is published in the original. 相似文献