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Li X.-Z.,Henan University of Science and Technology | Li X.-Z.,Luoyang Key Laboratory of Photoelectric Functional Materials | Tai Y.-P.,Henan University of Science and Technology | Nie Z.-G.,Nanyang Technological University | And 2 more authors.
Optik | Year: 2013

Dynamic speckle method was employed to characterize the profile quality of the aluminum plate in process of laser cutting. Speckle contrast as an indicator was used to study the relation of the distance between the focusing lens and the sample and the focus length. Experimental results show that this method is effective to characterize the laser cutting profile quality. © 2012 Elsevier GmbH.


Li X.-Z.,Henan University of Science and Technology | Li X.-Z.,Luoyang Key Laboratory of Photoelectric Functional Materials | Tai Y.-P.,Henan University of Science and Technology | Nie Z.-G.,Nanyang Technological University
Optik | Year: 2013

In this paper, the DSCM based on multi-scale wavelet transform (WT) was proposed. Firstly, the speckle pattern sequences generated by the sample were recorded before and after displacement. And then, these speckle patterns were multi-level decomposed used by sym8 and db4 wavelet family, respectively. Next step, correlation searching was conducted using their approximate profiles and obtained the displacement. Finally, we got a high precision results quickly. In comparison with the traditional DSCM, the correlation calculation efficiency of this new method is improved dramatically, at the same time, it could keep higher resolution. © 2013 Elsevier GmbH.


Li X.,Henan University of Science and Technology | Li X.,Luoyang Key Laboratory of Photoelectric Functional Materials | Tai Y.,Henan University of Science and Technology | Nie Z.,Nanyang Technological University | And 4 more authors.
Optics Communications | Year: 2013

We illustrated the propagation properties of optical vortices in random field based on Fresnel diffraction scheme using computer simulations. Vortex distribution, phase distribution and the zero-crossing lines of the real and imaginary parts of the optical field were analyzed comparatively in two dimensional space perpendicular to z direction. Then, the evolution of optical vortices was studied along propagation direction. And the relation between vortex density and the distance was analyzed. Moreover, the vortex lines were visualized and discussed in a cube of 256×256×256 μm 3 with speckle patterns and phase maps of different sections superposed. © 2012 Elsevier B.V.


Tai Y.P.,Henan University of Science and Technology | Li X.Z.,Henan University of Science and Technology | Li X.Z.,Luoyang Key Laboratory of Photoelectric Functional Materials | Nie Z.G.,Nanyang Technological University
Materials Technology | Year: 2013

Single crystal α-Fe2O3 nanotube was synthesised via refluxing in the organic solvent of nbutylalcohol that employed Fe(OH) 3 sol as precursor without any surfactant and dispersant. Then the final products were characterised by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM) and UV-Vis absorption spectroscopy. The XRD analysis confirmed trigonal crystal system α-Fe2O3 with high purity and good crystallinity, which were confirmed further by EDAX pattern. The TEM images displayed the morphology of α-Fe2O3 which was mainly nanotubes with outer diameters of 10-15 nm, inner diameters of 6-10 nm and length of 100-120 nm. The poly vinyl alcohol (PVA)-α-Fe2O3 nanocomposite obtained by doping the product in PVA showed a strong absorption both in UV and visible regions. Furthermore, the possible formation mechanism was proposed based on the experimental results, which revealed that the nanotubes were easily obtained in the interface of collide and n-butyl alcohol by the surface tension. © 2013 W. S. Maney & Son Ltd.

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