| 1. |
- Xia, Lixin, et al.
(författare)
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Selective reduction of nitroaromatic compounds on silver nanoparticles by visible light
- 2012
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Ingår i: Journal of Raman Spectroscopy. - : Wiley. - 1097-4555 .- 0377-0486. ; 43:8, s. 1024-1028
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, we report experimentally and theoretically that nitroaromatic compounds, 2,4-dinitrobenzenethiol and 4-chloro-2-nitrobenzenethiol, on silver sols can be selectively reduced to 2-amino-4-nitrobenzenethiol and 2-amino-4-chlorobenzenethiol simply by irradiating with a visible light in ambient conditions, and the selective photoreduction is a very facile process. The results of quantum chemical calculations are in good agreement with our experimental data. Copyright (c) 2012 John Wiley & Sons, Ltd.
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| 2. |
- Zhang, Yinlong, et al.
(författare)
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3D-SWiM : 3D vision based seam width measurement for industrial composite fiber layup in-situ inspection
- 2023
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845 .- 1879-2537. ; 82
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Tidskriftsartikel (refereegranskat)abstract
- Industrial composite fiber has been widely used in the high-end manufacturing because of its superior stiffness and strength. To ensure the quality of composite fiber placement in making high-end and lightweight aerospace products, it needs reliable composite fiber layup in-situ inspection. An accurate seam width measurement is an indispensable procedure during the layup inspection. However, the traditional seam measurements may fail in presence of surface curvature variance, curved edges between sheets, to name a few. This paper intentionally designs a novel 3D vision based Seam Width Measurement for Industrial Composite Fiber Layup In-situ Inspection (called 3D-SWiM). It aims to address three major challenges in measuring the seam width between the composite fiber sheets, namely, seam region over-segmentation, failures on region of interests (ROI) seam detection, seam width measurement inconsistency. Firstly, the region growing with semantic refinement is designed for 3D point cloud clustering, to overcome over-segmentation on seam regions. Afterwards, the gridding model with edge discrimination is applied to extract the 3D potential candidates in the edge areas. Eventually, we use the cubic B-spline fitting model to describe the seam region curves and the improved particle swarm optimization model to estimate the minimum and maximum distance between the seam edges. 3D-SWiM has been evaluated extensively on the developed composite fiber layup platform. The comparisons with the state-of-the-art methods (such as HT and GFM) on the region-of-interest segmentation, seam extraction and seam width measurement have been performed and the experimental results prove the competitive performance in composite fiber layup in-situ inspections.
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| 3. |
- Zhang, Yinlong, et al.
(författare)
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GCMVF-AGV : Globally Consistent Multiview Visual-Inertial Fusion for AGV Navigation in Digital Workshops
- 2023
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 72
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Tidskriftsartikel (refereegranskat)abstract
- An accurate and globally consistent navigation system is crucial for estimating the positions and attitudes of automated guided vehicles (AGVs) in digital workshops. A promising navigation technology for this purpose is tightly coupled visual-inertial fusion, which offers advantages such as quick response (QR), absolute scale, and accuracy. However, existing visual-inertial fusion systems have limitations, including long-term drift, tracking failures in textureless or poorly illuminated environments, and a lack of absolute references. To create a reliable and consistent AGV navigation framework and correct for long-term drift, we have designed a novel framework, globally consistent multiview visual-inertial fusion for AGV navigation (GCMVF-AGV). This framework uses a downward-looking QR vision sensor and a forward-looking visual-inertial sensor together to estimate AGV poses in real time. The downward camera provides absolute AGV positions and attitudes with reference to the global workshop frame. Furthermore, long-term visual-inertial drift, inertial biases, and velocities are periodically compensated between spatial intervals of QR codes by minimizing visual-inertial residuals with the rigid constraints of absolute poses estimated from the downward visual measurements. We have evaluated the proposed method on the developed AGV navigation platform, and experimental results demonstrate the position and attitude errors of less than 0.05 m and 2 degrees, respectively.
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