Mean shift is a widely used clustering algorithm in image segmentation. However, the segmenting results are not so good as expected when dealing with the texture surface due to the influence of the textures. Therefore...Mean shift is a widely used clustering algorithm in image segmentation. However, the segmenting results are not so good as expected when dealing with the texture surface due to the influence of the textures. Therefore, an approach based on wavelet transform (WT), co-occurrence matrix (COM) and mean shift is proposed in this paper. First, WT and COM are employed to extract the optimal resolution approximation of the original image as feature image. Then, mean shift is successfully used to obtain better detection results. Finally, experiments are done to show this approach is effective.展开更多
Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) ...Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) and TR(∞), where TR(t) denotes the time spent by X in BR up to time t and TR(∞) the total time of X spent in BR. Explicit formulas for the Laplace transform of TR(∞) and the double Laplace transform of TR(t) are obtained.展开更多
In this work, the nature, location and evolution of Cu+ ions in Cu-SAPO-34 are investigated by diffuse reflectance infrared Fourier transform spectrum(DRIFTS) of CO adsorption and density functional theory(DFT) calcul...In this work, the nature, location and evolution of Cu+ ions in Cu-SAPO-34 are investigated by diffuse reflectance infrared Fourier transform spectrum(DRIFTS) of CO adsorption and density functional theory(DFT) calculation. By combination with DFT results, characteristic Cu+–CO bands located at 2154 and 2136 cm.1 are attributed to CO adsorbed on Cu+ ions located at sites I(in the plane of six-membered ring connected to the large cages) and site II(in the eight-membered ring cages near the tilted four membered ring) in the framework of H-SAPO-34 zeolite. Subsequently, both the influences of Cu loading and preparation method are considered and discussed. By varying the Cu loading, the site-occupation preference of Cu+ ions on site I is confirmed,especially at low Cu loadings. Through elevating the desorption temperature, migration of Cu+ ions is revealed because of the adsorption-induced effect. Furthermore, a facile and more efficient approach to introduce Cu+ ions into CHA zeolite, compared with solid-state ion exchange with CuCl and conventional ion exchange in aqueous solution, and the different preparation methods also result in different occupations of Cu+ ions.展开更多
基金Project (No. 035115039) supported by the Scientific Committee of Shanghai, China
文摘Mean shift is a widely used clustering algorithm in image segmentation. However, the segmenting results are not so good as expected when dealing with the texture surface due to the influence of the textures. Therefore, an approach based on wavelet transform (WT), co-occurrence matrix (COM) and mean shift is proposed in this paper. First, WT and COM are employed to extract the optimal resolution approximation of the original image as feature image. Then, mean shift is successfully used to obtain better detection results. Finally, experiments are done to show this approach is effective.
基金Project supported by the National Natural Science Foundation of China (No.19801020) and the grant from the Research Grants Coun
文摘Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) and TR(∞), where TR(t) denotes the time spent by X in BR up to time t and TR(∞) the total time of X spent in BR. Explicit formulas for the Laplace transform of TR(∞) and the double Laplace transform of TR(t) are obtained.
基金supported by the National Natural Science Foundation of China(21325626,21406120)
文摘In this work, the nature, location and evolution of Cu+ ions in Cu-SAPO-34 are investigated by diffuse reflectance infrared Fourier transform spectrum(DRIFTS) of CO adsorption and density functional theory(DFT) calculation. By combination with DFT results, characteristic Cu+–CO bands located at 2154 and 2136 cm.1 are attributed to CO adsorbed on Cu+ ions located at sites I(in the plane of six-membered ring connected to the large cages) and site II(in the eight-membered ring cages near the tilted four membered ring) in the framework of H-SAPO-34 zeolite. Subsequently, both the influences of Cu loading and preparation method are considered and discussed. By varying the Cu loading, the site-occupation preference of Cu+ ions on site I is confirmed,especially at low Cu loadings. Through elevating the desorption temperature, migration of Cu+ ions is revealed because of the adsorption-induced effect. Furthermore, a facile and more efficient approach to introduce Cu+ ions into CHA zeolite, compared with solid-state ion exchange with CuCl and conventional ion exchange in aqueous solution, and the different preparation methods also result in different occupations of Cu+ ions.
