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Su Q.,Henan University of Urban Construction | Li L.,Fujian Engineering College | Li S.,Henan University of Urban Construction | Zhao H.,Henan University of Urban Construction
Materials Letters

Single-crystal nitrogen (N) doped p-type ZnSe nanobelts (NBs) with zinc blende structure were synthesized in ammonia atmosphere via a thermal evaporation method. The p-type conductivity of ZnSe:N NBs was confirmed by field-effect transistors (FETs) based on individual NBs. High-performance photodetectors were constructed based on ZnSe:N NBs, which show high sensitivity and relatively fast response speed to the incident light with a sharp cut-off at 460 nm, corresponding to the band-gap of ZnSe. The high photosensitivity and relatively fast response speed are attributable to the high crystal quality of the ZnTe nanowires. These results reveal that such single-crystalline ZnSe NBs are excellent candidates for optoelectronic applications. © 2012 Elsevier B.V. Source

Hydrothermal method synthesis of α-MnO2 nanowires has been achieved at different temperatures in this work. X-ray diffraction and transmission electron microscopy confirmed the pure phase of the α-MnO2 nanowires. All of the samples crystallized in a single-phase nanowires shape. The α-MnO2 nanowires diameter increased from 11 nm to 21 nm with the increase in hydrothermal temperature from 120 C to 200 C. The α-MnO2 catalytic activity on the decomposition of ammonium perchlorate (AP) was characterized through thermogravimetric analysis. The decomposition rate of AP with the addition of α-MnO2 was size relative. The 11 nm MnO2 nanowires exhibited the best catalytic activity, which lowered the high-temperature peak of AP by 130°C. © 2013 Elsevier Ltd. All rights reserved. Source

Wu Z.,Fujian Engineering College
Guangxue Xuebao/Acta Optica Sinica

A novel optical system is proposed, and it is composed of two biprisms with different bottom corners and one cylindrical lens. The technical problem that the striped regional of grating structure light generating by single biprism is so small that it cannot be applied to wide range measurement is solved. Physical processes of generating grating structure light is analyzed by geometrical optics, and relevant parameters are also calculated. The intensity distribution in different positions after system is simulated by Zemax software, and the intensity distribution with the change of system parameters, e.g. structure parameters of optical elements and relative position between optical elements, are also analyzed. The conclusion of simulation is consistent with that of geometrical optics theory. The result shows that when a plane wave illuminates on the novel optical system, the grating structure light with wide measurement area, low divergence degree and adjustment flexibulity is formed. Source

Lin Z.-H.,Fujian Engineering College
Guangzi Xuebao/Acta Photonica Sinica

Fringe center method is an important demodulation method for electronic speckle pattern interferometry fringe. The precondition of this method is to obtain fringe skeletons with high precision. Based on the analysis of carrier-wave electronic interferometry fringe characteristics, a fringe skeletons extracting method based on modulation direction was proposed. Firstly, a homomorphic filtering was used to filter the high frequency multiplicative speckle pattern noise effectively and pick out carrier-wave fringes. Then a fringe skeletons extracting algorithm based on modulation direction was applied to confirm the dots of gray scale extremum and make binarization processing. In order to get whole fringe skeletons map, the mending methods based on skeletons curve fitting or based on the fringe separation were adopted to compensate the edge fringe skeletons. Experimental results show that this method is simple and reliable. It can extract the consecutive fringe skeletons quickly and accurately. Source

Wu Z.-W.,Fujian Engineering College
Guangzi Xuebao/Acta Photonica Sinica

A novel optical element is presented for solving the problems that energy of non-diffracting-like linear structured beam generated by normal triangular-section prism is evenly distributed and not suitable to be used to three-dimensional surface measurement directly and energy efficiency of central spot is lower. This element is designed by gluing a platform with isosceles trapezoid section on the bottom of triangular-section prism. The beam transformation property of this element is analyzed with geometrical optics theory, and the conclusion shows that its property is the same as the combination of two normal triangular-section prisms with different bottom corner. When a plane wave illuminates on the novel optical element, non-diffracting-like linear structured beam which has higher intensity in the central spot is formed. Finally the intensity distribution is simulated by diffraction and interference theory. The results show that the conclusion of diffraction and interference theory is consistent with the conclusion of geometrical optics theory, and a better non-diffracting-like linear structured beam is generated by this novel optical element. Parameters that the central spot size of beam, non-diffracting range and so on can be adjusted easily through changing the structural parameters of the prism. Source

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