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Zheng L.-G.,Changchun Institute of Technology
Journal of Applied Optics

In order to solve stitching testing of precise optical flat mirror, based on least squares fitting, we established reasonable stitching algorithms and mathematical models. In addition, relative program was written and a Φ120 mm precise flat mirror was tested with stitching method. A marked point was used to accomplish the alignments between subspertures. At the same time, relative stitching accuracy was analyzed based on the full aperture testing result and self-examination subaperture testing result. It is proved from the experiment results that there is no gap in the stitching result. The peak value(PV) and root-mean-square(RMS) errors between stitching results and full aperture testing results are 0.020 λ and 0.002 λ respectively. The stitching result is in consistent with the full aperture testing result and self-examination testing result, respectively, which proves the reliability and accuracy of the stitching. Source

Zhao J.,Jilin University | Zhao J.,Changchun Institute of Technology | Liu L.,Jilin University
Knowledge-Based Systems

The isomorphic relationship between indiscernibility relation in rough set theory and nominal scale in formal concept analysis was studied in this paper, upon which the conceptual elements were constructed as the basic units of internal elements in a knowledge-based complex system. The nature of the association between conceptual elements was studied in this paper, where the definition and properties of association intensity were provided. Furthermore, concept granules were constructed by studying the mapping between conceptual elements. The general forms of expansion and aggregation of concept granules were also given. The theories in the study laid the foundation for evolutionary analysis of knowledge-based complex system, and offered a referential model to the studies on knowledge evolution of ontology engineering. © 2011 Elsevier B.V. All rights reserved. Source

Wang X.-K.,Changchun Institute of Technology
Journal of Applied Optics

On the basis of summing up conventional linearity error testing for guideway, a novel method for testing linearity error of very long guideway by laser tracker is proposed. The basic principle and testing processing of the method are analyzed and researched. A long guideway of 20 m is measured by this method, the linearity error of each direction is 27 μm and 25 μm respectively. This method enlarges the ability of the laser tracker, it can test the linearity error of long guideway precisely and swiftly, and it can separate the linearity error of two directions, the longth of measurement guideway can reach 70 m, and the testing precision is 0.4 μm/m. Source

Wang X.-K.,Changchun Institute of Technology
Journal of Applied Optics

On the basis of summing up conventional testing methods for convex mirror, a novel method for testing convex surfaces by subaperture stitching interferometry (SSI) was proposed. A sphere mirror is used as the reference surface, the phase distribution of each subaperture can be measured by the digital wavefront interferometer, and the full aperture surface map can be calculated by stitching several subapertures. The basic principle and theory of SSI were researched, and the stitching processing and prototype for testing convex spheres were devised and developed. A convex SiC sphere with the aperture of 300 mm was tested by SSI with 9 subapertures. For the validation, the sphere was also tested by large interferometer and beam expander, and the peak-valley(PV) and root-mean-square(RMS) residual errors between them were 0.102 λ and 0.009 λ, respectively (λ=632.8 nm). Source

Li S.,Changchun Institute of Technology
Advanced Materials Research

An efficient near-infrared (NIR) quantum cutting (QC) nanophospors with Ce 3+, Yb 3+ codoped in CaF 2 had been synthesized by hydrothermal method and characterized by X-ray powder diffraction, scanning electron microscope, transmission electron microscopy, photoluminescence spectra and decay dynamics. The nanoparticles were uniform and monodisperse. Under the excitation of 5d level of Ce 3+, an intense NIR emission at 900-1050nm was observed which match to the energy of Si band gap of Si - based solar cells. In the Ce 3+, Yb 3+ codoped CaF 2, the lifetime of Ce 3+ decreases and the quantum efficiency (QE) increases with increasing Yb 3+ concentration. © (2012) Trans Tech Publications. Source

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