Functional superhydrophobic coatings have attracted considerable attention because of their potential for a wide range of applications.In this study,a novel cyclotetrasiloxane-based hybrid superhydrophobic modifier(F-...Functional superhydrophobic coatings have attracted considerable attention because of their potential for a wide range of applications.In this study,a novel cyclotetrasiloxane-based hybrid superhydrophobic modifier(F-D_(4))was prepared for the first time using a mild thiolene click reaction of 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane(Vi-D_(4))with perfluorohexylethanethiol(PFOT)and mercaptopropyltrimethoxysilane(MPTMS)as the raw materials.Then,F-D_(4) was introduced into the fabric via a sol-gel process,resulting in a superhydrophobic fabric(F-D_(4)-Fabric).The surface characteristics of the modified fabric were determined using scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and water contact angle(WCA).The coated fabrics have outstanding mechanical,physical,and chemical stability,and exhibit excellent self-cleaning and anti-fouling properties.Owing to its superhydrophobicity,FD_(4)-Fabric could efficiently separate a range of oil/water mixtures with a separation efficiency of up to 99.99%.The study showed that the modification strategy used in the dip-coating process greatly affected the superhydrophobicity of the cotton fabric,which is useful for oil/water separation and self-cleaning applications.展开更多
Metasurfaces offer innovative approaches for manipulating electromagnetic waves at subwavelength scales.Recent advancements have focused on toroidal dipole(TD) and quasi-bound state in the continuum(quasi-BIC) modes,w...Metasurfaces offer innovative approaches for manipulating electromagnetic waves at subwavelength scales.Recent advancements have focused on toroidal dipole(TD) and quasi-bound state in the continuum(quasi-BIC) modes,which are particularly attractive due to their capacity to enhance light-matter interaction.However,most metasurfaces with TD and quasi-BIC modes exhibit passive electromagnetic responses after fabrication,limiting their practical applications.This study presents both numerical and experimental investigations that demonstrate the active control of TD and quasi-BIC modes through the integration of symmetric and asymmetric aluminum dumbbell aperture arrays with the phase-change material Ge2Sb2Te5(GST).The symmetric hybrid dumbbell aperture array shows a pronounced TD response within the terahertz frequency range.In contrast,modifying the geometric parameters to disrupt the structural symmetry induces a quasi-BIC mode in the asymmetric hybrid dumbbell aperture array.Furthermore,as GST undergoes a phase transition from its amorphous to crystalline state,both TD and quasi-BIC modes become dynamically tunable,driven by changes in the conductivity of GST.Notably,significant modulation of the transmitted terahertz wave occurs around the frequencies corresponding to the TD and quasi-BIC modes during the GST phase transition.Symmetric and asymmetric hybrid dumbbell aperture arrays provide a versatile platform for generating tunable TD and quasi-BIC modes,with promising applications in terahertz modulators and filters.展开更多
We propose an automatic video segmentation method based on an optimized SaliencyCut equipped with information centroid(IC)detection according to level balance principle in physical theory.Unlike the existing methods,t...We propose an automatic video segmentation method based on an optimized SaliencyCut equipped with information centroid(IC)detection according to level balance principle in physical theory.Unlike the existing methods,the image information of another dimension is provided by the IC to enhance the video segmentation accuracy.Specifically,our IC is implemented based on the information-level balance principle in the image,and denoted as the information pivot by aggregating all the image information to a point.To effectively enhance the saliency value of the target object and suppress the background area,we also combine the color and the coordinate information of the image in calculating the local IC and the global IC in the image.Then saliency maps for all frames in the video are calculated based on the detected IC.By applying IC smoothing to enhance the optimized saliency detection,we can further correct the unsatisfied saliency maps,where sharp variations of colors or motions may exist in complex videos.Finally,we obtain the segmentation results based on IC-based saliency maps and optimized SaliencyCut.Our method is evaluated on the DAVIS dataset,consisting of different kinds of challenging videos.Comparisons with the state-of-the-art methods are also conducted to evaluate our method.Convincing visual results and statistical comparisons demonstrate its advantages and robustness for automatic video segmentation.展开更多
基金financially supported by the National Key R&D Program of China(No.2022YFE0197000)。
文摘Functional superhydrophobic coatings have attracted considerable attention because of their potential for a wide range of applications.In this study,a novel cyclotetrasiloxane-based hybrid superhydrophobic modifier(F-D_(4))was prepared for the first time using a mild thiolene click reaction of 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane(Vi-D_(4))with perfluorohexylethanethiol(PFOT)and mercaptopropyltrimethoxysilane(MPTMS)as the raw materials.Then,F-D_(4) was introduced into the fabric via a sol-gel process,resulting in a superhydrophobic fabric(F-D_(4)-Fabric).The surface characteristics of the modified fabric were determined using scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and water contact angle(WCA).The coated fabrics have outstanding mechanical,physical,and chemical stability,and exhibit excellent self-cleaning and anti-fouling properties.Owing to its superhydrophobicity,FD_(4)-Fabric could efficiently separate a range of oil/water mixtures with a separation efficiency of up to 99.99%.The study showed that the modification strategy used in the dip-coating process greatly affected the superhydrophobicity of the cotton fabric,which is useful for oil/water separation and self-cleaning applications.
基金National Natural Science Foundation of China(12304434, 12304433, 12204446, 12004361, 12004362)Natural Science Foundation of Zhejiang Province(LY22A040006)+1 种基金Fundamental Research Funds for the Provincial Universities of Zhejiang (2023YW06,2023YW01)State Key Laboratory of Millimeter Waves(K202429)
文摘Metasurfaces offer innovative approaches for manipulating electromagnetic waves at subwavelength scales.Recent advancements have focused on toroidal dipole(TD) and quasi-bound state in the continuum(quasi-BIC) modes,which are particularly attractive due to their capacity to enhance light-matter interaction.However,most metasurfaces with TD and quasi-BIC modes exhibit passive electromagnetic responses after fabrication,limiting their practical applications.This study presents both numerical and experimental investigations that demonstrate the active control of TD and quasi-BIC modes through the integration of symmetric and asymmetric aluminum dumbbell aperture arrays with the phase-change material Ge2Sb2Te5(GST).The symmetric hybrid dumbbell aperture array shows a pronounced TD response within the terahertz frequency range.In contrast,modifying the geometric parameters to disrupt the structural symmetry induces a quasi-BIC mode in the asymmetric hybrid dumbbell aperture array.Furthermore,as GST undergoes a phase transition from its amorphous to crystalline state,both TD and quasi-BIC modes become dynamically tunable,driven by changes in the conductivity of GST.Notably,significant modulation of the transmitted terahertz wave occurs around the frequencies corresponding to the TD and quasi-BIC modes during the GST phase transition.Symmetric and asymmetric hybrid dumbbell aperture arrays provide a versatile platform for generating tunable TD and quasi-BIC modes,with promising applications in terahertz modulators and filters.
基金This work was supported in part by the Major Project of the New Generation of Artificial Intelligence of National Key Research and Development Project,Ministry of Science and Technology of China under Grant No.2018AAA0102900the National Natural Science Foundation of China under Grant Nos.61572328 and 61973221+1 种基金the Natural Science Foundation of Guangdong Province of China under Grant Nos.2018A030313381 and 2019A1515011165The Hong Kong Polytechnic University under Grant Nos.P0030419 and P0030929.
文摘We propose an automatic video segmentation method based on an optimized SaliencyCut equipped with information centroid(IC)detection according to level balance principle in physical theory.Unlike the existing methods,the image information of another dimension is provided by the IC to enhance the video segmentation accuracy.Specifically,our IC is implemented based on the information-level balance principle in the image,and denoted as the information pivot by aggregating all the image information to a point.To effectively enhance the saliency value of the target object and suppress the background area,we also combine the color and the coordinate information of the image in calculating the local IC and the global IC in the image.Then saliency maps for all frames in the video are calculated based on the detected IC.By applying IC smoothing to enhance the optimized saliency detection,we can further correct the unsatisfied saliency maps,where sharp variations of colors or motions may exist in complex videos.Finally,we obtain the segmentation results based on IC-based saliency maps and optimized SaliencyCut.Our method is evaluated on the DAVIS dataset,consisting of different kinds of challenging videos.Comparisons with the state-of-the-art methods are also conducted to evaluate our method.Convincing visual results and statistical comparisons demonstrate its advantages and robustness for automatic video segmentation.
