On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni?Yb binary system was carried out using the CALPHAD (calculation of p...On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni?Yb binary system was carried out using the CALPHAD (calculation of phase diagrams) method. The liquid phase is modeled as the associate model with the constituent species Ni, Yb and YbNi3, owing to the sharp change of the enthalpy of mixing of liquid phase at the composition of around 25% Yb (mole fraction). The terminal solid solutions FCC_A1 (Ni/Yb) and BCC_A2 (Yb) are described by the substitutional solution model with the Redlich?Kister polynomial. The intermetallic compounds, Yb2Ni17, YbNi5, YbNi3, YbNi2, α-YbNi and β-YbNi, are treated as strict stoichiometric compounds, since there are no noticeable homogeneity ranges reported for these compounds. A set of self-consistent thermodynamic parameters for the Ni?Yb binary system are obtained. According to the presently assessed results, the thermochemical properties and the phase boundary data can be well reproduced.展开更多
To evaluate the homogeneity of asphalt mixtures,the images of sections obtained by cutting the asphalt mixtures specimen horizontally or vertically were analyzed with digital image processing techniques,and the partic...To evaluate the homogeneity of asphalt mixtures,the images of sections obtained by cutting the asphalt mixtures specimen horizontally or vertically were analyzed with digital image processing techniques,and the particle area ratio was achieved by applying sector scan for horizontal specimen and vertical scan for vertical one.The research result indicates that the influence of random distribution of aggregates in cutting the specimen can be eliminated by using colored aggregates to distinguish coarse and fine aggregates and using color threshold to segment the images.Choosing three typical gradations,proving particle area ratio obeying normal distribution and using the variability of particle area ratio as an index,it is feasible to quantitatively evaluate the homogeneity of asphalt mixtures.展开更多
Intravascular ultrasound( IVUS) is an important imaging technique that is used to study vascular wall architecture for diagnosis and assessment of the vascular diseases. Segmentation of lumen and media-adventitia boun...Intravascular ultrasound( IVUS) is an important imaging technique that is used to study vascular wall architecture for diagnosis and assessment of the vascular diseases. Segmentation of lumen and media-adventitia boundaries from IVUS images is a basic and necessary step for quantitative assessment of the vascular walls.Due to ultrasound speckles, artifacts and individual differences,automated segmentation of IVUS images represents a challenging task. In this paper,a random walk based method is proposed for fully automated segmentation of IVUS images. Robust and accurate determination of the seed points for different regions is the key to successful use of the random walk algorithm in segmentation of IVUS images and is the focus of the present work. Performance of the proposed algorithm was evaluated over an image database with 900 IVUS image frames of nine patient cases. The preliminary experimental results show the potential of the proposed IVUS image segmentation approach.展开更多
基金Project(51271027)supported by the National Natural Science Foundation of ChinaProject(T201308)supported by Shenzhen Key Laboratory of Special Functional Materials of Shenzhen University,China
文摘On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni?Yb binary system was carried out using the CALPHAD (calculation of phase diagrams) method. The liquid phase is modeled as the associate model with the constituent species Ni, Yb and YbNi3, owing to the sharp change of the enthalpy of mixing of liquid phase at the composition of around 25% Yb (mole fraction). The terminal solid solutions FCC_A1 (Ni/Yb) and BCC_A2 (Yb) are described by the substitutional solution model with the Redlich?Kister polynomial. The intermetallic compounds, Yb2Ni17, YbNi5, YbNi3, YbNi2, α-YbNi and β-YbNi, are treated as strict stoichiometric compounds, since there are no noticeable homogeneity ranges reported for these compounds. A set of self-consistent thermodynamic parameters for the Ni?Yb binary system are obtained. According to the presently assessed results, the thermochemical properties and the phase boundary data can be well reproduced.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50808087)
文摘To evaluate the homogeneity of asphalt mixtures,the images of sections obtained by cutting the asphalt mixtures specimen horizontally or vertically were analyzed with digital image processing techniques,and the particle area ratio was achieved by applying sector scan for horizontal specimen and vertical scan for vertical one.The research result indicates that the influence of random distribution of aggregates in cutting the specimen can be eliminated by using colored aggregates to distinguish coarse and fine aggregates and using color threshold to segment the images.Choosing three typical gradations,proving particle area ratio obeying normal distribution and using the variability of particle area ratio as an index,it is feasible to quantitatively evaluate the homogeneity of asphalt mixtures.
基金Innovation Program of Shanghai Municipal Education Commission,China(No.13YZ136)National Science&Technology Support Program during the 12th Five-Year Plan Period of China(No.2012BAI13B02)
文摘Intravascular ultrasound( IVUS) is an important imaging technique that is used to study vascular wall architecture for diagnosis and assessment of the vascular diseases. Segmentation of lumen and media-adventitia boundaries from IVUS images is a basic and necessary step for quantitative assessment of the vascular walls.Due to ultrasound speckles, artifacts and individual differences,automated segmentation of IVUS images represents a challenging task. In this paper,a random walk based method is proposed for fully automated segmentation of IVUS images. Robust and accurate determination of the seed points for different regions is the key to successful use of the random walk algorithm in segmentation of IVUS images and is the focus of the present work. Performance of the proposed algorithm was evaluated over an image database with 900 IVUS image frames of nine patient cases. The preliminary experimental results show the potential of the proposed IVUS image segmentation approach.
