Hydrogels have been widely applied in agricultural drought-resistance,pollution regulation,drug delivery and so on.Acrylamide(AM)is usually used as raw material to synthesize acrylamide hydrogels.However,inherently lo...Hydrogels have been widely applied in agricultural drought-resistance,pollution regulation,drug delivery and so on.Acrylamide(AM)is usually used as raw material to synthesize acrylamide hydrogels.However,inherently low mechanical strength greatly limits their applications in some special areas.Therefore,it is necessary to choose suitable functional monomers to optimize acrylamide hydrogels and improve their mechanical performances.In this paper,a novel acrylamide monomer modified by rosin was synthesized,and then polyacrylamide/rosinbased acrylamide(RAM)composite hydrogels were prepared via free radical polymerization using potassium persulfate as initiator,N,N′-methylene-bisacrylamide(MBA)as a crosslinker.The influence of RAM monomer was investigated in detail.The chemical structure,pore structure,swelling properties,thermal performances and mechanical properties of composite hydrogels were characterized by Fourier Transform Infrared spectrometer(FT-IR),thermogravimetric analysis(TG),scanning electron microscope(SEM),and universal testing,respectively.The results showed that the thermal stability and mechanical property of RAM hydrogels were improved significantly.The compressive strength of RAM hydrogels was increased to 3.5 times than that of AM hydrogels,and the tensile strength was 5.1 times compared with AM hydrogels as well.Moreover,RAM hydrogels exhibited a faster initial swelling rate due to the new pore structure formed after introducing the RAM monomer.展开更多
As fixed compression ratio is used in traditional deep space exploration image transmission application,the same compression code rate is allocated to each image.However,since the information of each image in a space ...As fixed compression ratio is used in traditional deep space exploration image transmission application,the same compression code rate is allocated to each image.However,since the information of each image in a space observation mission is nonuniform,the image with more information will inevitably lead to more compression distortion than the image with less information.Obviously,it’s not an efficient way to transmit information in terms of data importance or overall distortion.Therefore,we proposed a combinatorial optimal bit rate allocation algorithm to improve the efficiency of image transmission in space application.Different from traditional method,the rate-distortion model of wavelet coefficients for each image in a transmission task was built,and under the overall maximum transmission rate constraint,an bit-rate optimal allocation was applied for each image to minimize the overall distortion of a batch of images.The proposed algorithm can be widely used in image compression algorithm with embedded code stream characteristics,such as JPEG2000 and SPIHT.Experimental results shows that in the range of 2.6 to 10 compression ratio,the algorithm can reduce image distortion MSB by 40%~64%at the same overall transmission code rate,which equivalent to improvement of PSNR 3 dB to 5.4 dB.展开更多
Learning-based approaches have made substantial progress in capturing spatially-varying bidirectional reflectance distribution functions(SVBRDFs)from a single image with unknown lighting and geometry.However,most exis...Learning-based approaches have made substantial progress in capturing spatially-varying bidirectional reflectance distribution functions(SVBRDFs)from a single image with unknown lighting and geometry.However,most existing networks only consider per-pixel losses which limit their capability to recover local features such as smooth glossy regions.A few generative adversarial networks use multiple discriminators for different parameter maps,increasing network complexity.We present a novel end-to-end generative adversarial network(GAN)to recover appearance from a single picture of a nearly-flat surface lit by flash.We use a single unified adversarial framework for each parameter map.An attention module guides the network to focus on details of the maps.Furthermore,the SVBRDF map loss is combined to prevent paying excess attention to specular highlights.We demonstrate and evaluate our method on both public datasets and real data.Quantitative analysis and visual comparisons indicate that our method achieves better results than the state-of-the-art in most cases.展开更多
基金supported by National Natural Science Foundation of China(32171722,31470597,31600462).
文摘Hydrogels have been widely applied in agricultural drought-resistance,pollution regulation,drug delivery and so on.Acrylamide(AM)is usually used as raw material to synthesize acrylamide hydrogels.However,inherently low mechanical strength greatly limits their applications in some special areas.Therefore,it is necessary to choose suitable functional monomers to optimize acrylamide hydrogels and improve their mechanical performances.In this paper,a novel acrylamide monomer modified by rosin was synthesized,and then polyacrylamide/rosinbased acrylamide(RAM)composite hydrogels were prepared via free radical polymerization using potassium persulfate as initiator,N,N′-methylene-bisacrylamide(MBA)as a crosslinker.The influence of RAM monomer was investigated in detail.The chemical structure,pore structure,swelling properties,thermal performances and mechanical properties of composite hydrogels were characterized by Fourier Transform Infrared spectrometer(FT-IR),thermogravimetric analysis(TG),scanning electron microscope(SEM),and universal testing,respectively.The results showed that the thermal stability and mechanical property of RAM hydrogels were improved significantly.The compressive strength of RAM hydrogels was increased to 3.5 times than that of AM hydrogels,and the tensile strength was 5.1 times compared with AM hydrogels as well.Moreover,RAM hydrogels exhibited a faster initial swelling rate due to the new pore structure formed after introducing the RAM monomer.
文摘As fixed compression ratio is used in traditional deep space exploration image transmission application,the same compression code rate is allocated to each image.However,since the information of each image in a space observation mission is nonuniform,the image with more information will inevitably lead to more compression distortion than the image with less information.Obviously,it’s not an efficient way to transmit information in terms of data importance or overall distortion.Therefore,we proposed a combinatorial optimal bit rate allocation algorithm to improve the efficiency of image transmission in space application.Different from traditional method,the rate-distortion model of wavelet coefficients for each image in a transmission task was built,and under the overall maximum transmission rate constraint,an bit-rate optimal allocation was applied for each image to minimize the overall distortion of a batch of images.The proposed algorithm can be widely used in image compression algorithm with embedded code stream characteristics,such as JPEG2000 and SPIHT.Experimental results shows that in the range of 2.6 to 10 compression ratio,the algorithm can reduce image distortion MSB by 40%~64%at the same overall transmission code rate,which equivalent to improvement of PSNR 3 dB to 5.4 dB.
基金supported by the National Natural Science Foundation of China(No.61602416)Shaoxing Science and Technology Plan Project(No.2020B41006).
文摘Learning-based approaches have made substantial progress in capturing spatially-varying bidirectional reflectance distribution functions(SVBRDFs)from a single image with unknown lighting and geometry.However,most existing networks only consider per-pixel losses which limit their capability to recover local features such as smooth glossy regions.A few generative adversarial networks use multiple discriminators for different parameter maps,increasing network complexity.We present a novel end-to-end generative adversarial network(GAN)to recover appearance from a single picture of a nearly-flat surface lit by flash.We use a single unified adversarial framework for each parameter map.An attention module guides the network to focus on details of the maps.Furthermore,the SVBRDF map loss is combined to prevent paying excess attention to specular highlights.We demonstrate and evaluate our method on both public datasets and real data.Quantitative analysis and visual comparisons indicate that our method achieves better results than the state-of-the-art in most cases.