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58 results on '"Xu, Xiaodong"'

27. Laser Operation of Tm: LuAG Single-Crystal Fiber Grown by the Micro-Pulling down Method

Author

Liu, Jian, primary, Dong, Jifei, additional, Wang, Yinyin, additional, Yuan, Hangqi, additional, Song, Qingsong, additional, Xue, Yanyan, additional, Xu, Jie, additional, Liu, Peng, additional, Li, Dongzhen, additional, Lebbou, Kheirreddine, additional, Wang, Zhanxin, additional, Zhao, Yongguang, additional, Xu, Xiaodong, additional, and Xu, Jun, additional

Published
2021
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34. Strain Rate of Metal Deformation in the Machining Process from a Fluid Flow Perspective

Author

Xu Xiaodong, Zhang Keguo, Zhanqiang Liu, and Wang Keyi

Subjects
0209 industrial biotechnology, fluid flow, Materials science, Flow (psychology), Mechanical engineering, 02 engineering and technology, strain rates, lcsh:Technology, lcsh:Chemistry, 020901 industrial engineering & automation, 0203 mechanical engineering, Machining, Fluid dynamics, General Materials Science, Instrumentation, lcsh:QH301-705.5, Fluid Flow and Transfer Processes, dislocation, deformation mechanism, lcsh:T, Process Chemistry and Technology, Rake, General Engineering, Strain rate, lcsh:QC1-999, Computer Science Applications, Shear (sheet metal), 020303 mechanical engineering & transports, Deformation mechanism, lcsh:Biology (General), lcsh:QD1-999, lcsh:TA1-2040, Deformation (engineering), lcsh:Engineering (General). Civil engineering (General), lcsh:Physics, machining
Abstract

Metal cutting speeds are getting faster with the development of high-speed cutting technology, and with the increase in cutting speed, the strain rate will become larger, which makes the study of the metal cutting process more inconvenient. At the same time, with the increase in strain rate, the dislocation movement controlling the plastic deformation mechanism of metal will change from thermal activation to a damping mechanism, which makes the metal deformation behave more like a fluid. Therefore, it is necessary to explore new ways of studying machining from the perspective of fluid flow. Based on this, a fluid model of the metal cutting process is established, and a method for calculating the strain rate is proposed from the point of view of flow. The results of the simulation and measurements are compared and analyzed. The results show that the strain rate on the rake face will be affected by the friction between the chip and tool, the nearer the distance between the chip layer and tool rake face, the bigger the strain rate will be. The strain rate in the central shear plane is much larger than in other areas along the shear plane direction, and in which two ends are the biggest. It can achieve rougher, quantitative research. This shows it is feasible to study machining from the viewpoint of fluid flow, though it still needs a lot of theoretical support and experimental confirmation.

Published
2020

35. A Deep-Learning-based 3D Defect Quantitative Inspection System in CC Products Surface

Author

Xiao Hong, Xu Xiaodong, Yi Zhang, Fangfang Li, Yang Feng, and Liming Zhao

Subjects
Surface (mathematics), Computer science, neural network, defect detection, 0211 other engineering and technologies, 02 engineering and technology, lcsh:Chemical technology, 01 natural sciences, Biochemistry, Article, surface defects, Analytical Chemistry, Image (mathematics), Computer vision, lcsh:TP1-1185, Electrical and Electronic Engineering, Instrumentation, 021102 mining & metallurgy, 3d imaging, business.industry, Deep learning, 010401 analytical chemistry, Inspection method, Process (computing), deep learning, continuous casting, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Continuous casting, Artificial intelligence, business
Abstract

To create an intelligent surface region of interests (ROI) 3D quantitative inspection strategy a reality in the continuous casting (CC) production line, an improved 3D laser image scanning system (3D-LDS) was established based on binocular imaging and deep-learning techniques. In 3D-LDS, firstly, to meet the requirements of the industrial application, the CCD laser image scanning method was optimized in high-temperature experiments and secondly, we proposed a novel region proposal method based on 3D ROI initial depth location for effectively suppressing redundant candidate bounding boxes generated by pseudo-defects in a real-time inspection process. Thirdly, a novel two-step defects inspection strategy was presented by devising a fusion deep CNN model which combined fully connected networks (for defects classification/recognition) and fully convolutional networks (for defects delineation). The 3D-LDS&rsquo, dichotomous inspection method of defects classification and delineation processes are helpful in understanding and addressing challenges for defects inspection in CC product surfaces. The applicability of the presented methods is mainly tied to the surface quality inspection for slab, strip and billet products.

Published
2020

36. Mid-IR Optical Property of Dy:CaF2-SrF2 Crystal Fabricated by Multicrucible Temperature Gradient Technology

Author

Jianbin Zhao, Xu Xiaodong, Hui Lin, Liangbi Su, Ruiqin Yang, Haifeng Lu, Yang Liu, Jian Liu, Fang-fang Ruan, Lihe Zheng, Yangxiao Wang, Weichao Chen, and Yan-yan Xue

Subjects
Diffraction, Materials science, General Chemical Engineering, Analytical chemistry, Crystal growth, 02 engineering and technology, 01 natural sciences, 010309 optics, Inorganic Chemistry, Crystal, 0103 physical sciences, Dispersion (optics), midinfrared crystal, Sellmeier dispersion formula, General Materials Science, temperature gradient technology, Crystallography, Dopant, crystal growth, Dy:CaF2-SrF2, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Full width at half maximum, Wavelength, QD901-999, 0210 nano-technology, Refractive index
Abstract

Dy3+-doped CaF2-SrF2 crystals with various Dy3+ dopant concentrations were synthesized by multicrucible temperature gradient technology (MC-TGT). Dy:CaF2-SrF2 crystals were fluorite structured and crystallized in cubic Fm3¯m space group, as characterized by X-ray diffraction. The crystallographic site concentration was calculated from the measured density by Archimedes’ hydrostatic weighing principle. The optical transmission reached over 90% with a sample thickness of 1.0 mm. The Sellmeier dispersion formula was obtained following the measured refractive index in a mid-IR range of 1.7–11 μm. Absorption coefficients of 6.06 cm−1 and 12.71 cm−1 were obtained at 804 nm and 1094 nm in 15% Dy:CaF2-SrF2 crystal. The fluorescence spectra of 15 at.% Dy:CaF2-SrF2 showed the strongest wavelength peak at 2919 nm with a full width at half maximum (FWHM) of 267 nm under an excitation wavelength of 808 nm. The fluorescence lifetimes were illustrated for different Dy3+ dopant levels of 5%, 10% and 15%. The results indicate that the Dy:CaF2-SrF2 crystal is a promising candidate for compact mid-IR lasers.

Published
2021

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