In this paper,a CFD/CSD model coupling N-S equations and structural equations of motion in the time domain is described for aeroelastic analysis of large wind turbines.The structural modes of blades are analyzed with ...In this paper,a CFD/CSD model coupling N-S equations and structural equations of motion in the time domain is described for aeroelastic analysis of large wind turbines.The structural modes of blades are analyzed with one-dimensional beam models.By combining point matched sliding grid for wind turbine rotation and deforming grid for structural vibrations,a hybrid dynamic grid strategy is designed for the multi-block structured grid system of a wind turbine.The dual time-stepping approach and finite volume scheme are applied to the three-dimensional unsteady preconditioned N-S equations,and DES approach is employed to simulate the unsteady massively separated flows.A modal approach is adopted to calculate the structural response,and a predictor-corrector scheme is used to solve the structural equations of motion.CFD and CSD solvers are tightly coupled via successive iterations within each physical time step.As a result,a time-domain CFD/CSD model for aeroelastic analysis of a large wind turbine is achieved.The presented method is applied to the NH1500 large wind turbine under the rated condition,and the calculated aeroelastic characteristics agree well with those of the prescribed vortex wake method.展开更多
In this paper, a novel space domain watermarking scheme based on image content is presented. The proposed method can use the human visual system(HVS) to adaptively embed a watermark in an image by decomposing the host...In this paper, a novel space domain watermarking scheme based on image content is presented. The proposed method can use the human visual system(HVS) to adaptively embed a watermark in an image by decomposing the host image, selecting streak blocks, modifying the intensities of the block. Experimental results show that the watermarking scheme proposed in this paper is invisible and robust to cropping, and also has good robustness to compression, filtering, noise adding, image enhancement, and mosaic.展开更多
The Nansha Block(NB)is one of the blocks separated from the southern margin of the South China Craton(SCC)by the western Pacific subduction,which contains rich information of geodynamic and tectonic transformation.To ...The Nansha Block(NB)is one of the blocks separated from the southern margin of the South China Craton(SCC)by the western Pacific subduction,which contains rich information of geodynamic and tectonic transformation.To reveal the essence of western Paleo-Pacific subduction during the Triassic period,Well NK-1 in this block was selected for petrographic study,and published research data from other cooperative teams were compared.A double-cycle pattern of basic to neutral magmatic volcanism was established,and 36 lithological rhythmic layers and representative cryptoexplosive breccia facies and welded tuff bands were identified.Combined with a reanalysis of published geochronological data,geochemical elements,and isotope geochemistry,we found that the rock assemblages could be divided into an intermediate-acid dacite(DA)series(SiO_(2)>65%)and basaltic(BA)series(Co<40μg/g),which was formed during the early Late Triassic((218.6±3.2)–(217.9±3.5)Ma).BA exhibits obvious calc-alkaline island-arc magmatic properties:(^(87)Sr/^(86)Sr)_i ratio ranging 0.70377–0.71118(average:0.70645),^(147)Sm/^(144)Nd ratio ranging 0.119–0.193(average:0.168),and chondrite-normalized rare earth element(REE)curves being flat,while DA exhibits remarkable characteristics of subducted island-arc andesitic magma:(^(87)Sr/^(86)Sr)_i ratio(0.70939–0.71129;average:0.71035),εNd(t)value(-6.2–-4.8;average:-5.6)andε_(Hf)(t)value(-2.9–-1.7,average:-2.2)show obvious crust-mantle mixing characteristics.BA and DA reveal typical characteristics of island-arc magma systems and typeⅡenriched mantle(EM-Ⅱ)magma.BA magma was likely resulted from the process whereby the continental crust frontal accretionary wedge was driven by the Paleo-Pacific slab subduction into the deep and began to melt,resulting in a large amount of melt(fluid)joined the asthenosphere on the side of the continental margin.In contrast,DA magma was likely resulted from the process whereby the plate front was forced to bend with increasing subduction distance,which triggered展开更多
Abstract We first consider the group inverses of the block matrices（AB0C）over a weakly finite ring. Then we study the sufficient and necessary conditions for the existence and the representations of the group invers...Abstract We first consider the group inverses of the block matrices（AB0C）over a weakly finite ring. Then we study the sufficient and necessary conditions for the existence and the representations of the group inverses of the block matrices（ABCD）over a ring with unity 1 under the following conditions respectively： （i） B = C, D = 0,B#and（BπA0#both exist; （ii） B is invertible and m = n;（iii）A#and （D - CA#B）# both exist, C = CAA#, where A and D are m × m and n × n matrices, respectively.展开更多
Fast algorithms for reducing encoding complexity of fractal image coding have recently been an important research topic. Search of the best matched domain block is the most computation intensive part of the fractal en...Fast algorithms for reducing encoding complexity of fractal image coding have recently been an important research topic. Search of the best matched domain block is the most computation intensive part of the fractal encoding process. In this paper, a fast fractal approximation coding scheme implemented on a personal computer based on matching in range block's neighbours is presented.Experimental results show that the proposed algorithm is very simple in implementation, fast in encoding time and high in compression ratio while PSNR is almost the same as compared with Barnsley's fractal block coding .展开更多
Ceramic tiles are one of the most indispensable materials for interior decoration.The ceramic patterns can’t match the design requirements in terms of diversity and interactivity due to their natural textures.In this...Ceramic tiles are one of the most indispensable materials for interior decoration.The ceramic patterns can’t match the design requirements in terms of diversity and interactivity due to their natural textures.In this paper,we propose a sketch-based generation method for generating diverse ceramic tile images based on a hand-drawn sketches using Generative Adversarial Network(GAN).The generated tile images can be tailored to meet the specific needs of the user for the tile textures.The proposed method consists of four steps.Firstly,a dataset of ceramic tile images with diverse distributions is created and then pre-trained based on GAN.Secondly,for each ceramic tile image in the dataset,the corresponding sketch image is generated and then the mapping relationship between the images is trained based on a sketch extraction network using ResNet Block and jump connection to improve the quality of the generated sketches.Thirdly,the sketch style is redefined according to the characteristics of the ceramic tile images and then double cross-domain adversarial loss functions are employed to guide the ceramic tile generation network for fitting in the direction of the sketch style and to improve the training speed.Finally,we apply hidden space perturbation and interpolation for further enriching the output textures style and satisfying the concept of“one style with multiple faces”.We conduct the training process of the proposed generation network on 2583 ceramic tile images dataset.To measure the generative diversity and quality,we use Frechet Inception Distance(FID)and Blind/Referenceless Image Spatial Quality Evaluator(BRISQUE)metrics.The experimental results prove that the proposed model greatly enhances the generation results of the ceramic tile images,with FID of 32.47 and BRISQUE of 28.44.展开更多
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2007CB714600)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘In this paper,a CFD/CSD model coupling N-S equations and structural equations of motion in the time domain is described for aeroelastic analysis of large wind turbines.The structural modes of blades are analyzed with one-dimensional beam models.By combining point matched sliding grid for wind turbine rotation and deforming grid for structural vibrations,a hybrid dynamic grid strategy is designed for the multi-block structured grid system of a wind turbine.The dual time-stepping approach and finite volume scheme are applied to the three-dimensional unsteady preconditioned N-S equations,and DES approach is employed to simulate the unsteady massively separated flows.A modal approach is adopted to calculate the structural response,and a predictor-corrector scheme is used to solve the structural equations of motion.CFD and CSD solvers are tightly coupled via successive iterations within each physical time step.As a result,a time-domain CFD/CSD model for aeroelastic analysis of a large wind turbine is achieved.The presented method is applied to the NH1500 large wind turbine under the rated condition,and the calculated aeroelastic characteristics agree well with those of the prescribed vortex wake method.
文摘In this paper, a novel space domain watermarking scheme based on image content is presented. The proposed method can use the human visual system(HVS) to adaptively embed a watermark in an image by decomposing the host image, selecting streak blocks, modifying the intensities of the block. Experimental results show that the watermarking scheme proposed in this paper is invisible and robust to cropping, and also has good robustness to compression, filtering, noise adding, image enhancement, and mosaic.
基金the National Natural Science Foundation of China(No.42206073)the National Key R&D Program of China(No.2021YFC3100600)+5 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110782)the China Post-doctoral Science Foundation(No.2021M703296)the Open Fund of the Key Laboratory of Tectonic Controlled Mineralization and Oil Reservoir of the Ministry of Natural Resources(No.gzck202101)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0206)the K.C.Wong Education Foundation(No.GJTD-2018-13)。
文摘The Nansha Block(NB)is one of the blocks separated from the southern margin of the South China Craton(SCC)by the western Pacific subduction,which contains rich information of geodynamic and tectonic transformation.To reveal the essence of western Paleo-Pacific subduction during the Triassic period,Well NK-1 in this block was selected for petrographic study,and published research data from other cooperative teams were compared.A double-cycle pattern of basic to neutral magmatic volcanism was established,and 36 lithological rhythmic layers and representative cryptoexplosive breccia facies and welded tuff bands were identified.Combined with a reanalysis of published geochronological data,geochemical elements,and isotope geochemistry,we found that the rock assemblages could be divided into an intermediate-acid dacite(DA)series(SiO_(2)>65%)and basaltic(BA)series(Co<40μg/g),which was formed during the early Late Triassic((218.6±3.2)–(217.9±3.5)Ma).BA exhibits obvious calc-alkaline island-arc magmatic properties:(^(87)Sr/^(86)Sr)_i ratio ranging 0.70377–0.71118(average:0.70645),^(147)Sm/^(144)Nd ratio ranging 0.119–0.193(average:0.168),and chondrite-normalized rare earth element(REE)curves being flat,while DA exhibits remarkable characteristics of subducted island-arc andesitic magma:(^(87)Sr/^(86)Sr)_i ratio(0.70939–0.71129;average:0.71035),εNd(t)value(-6.2–-4.8;average:-5.6)andε_(Hf)(t)value(-2.9–-1.7,average:-2.2)show obvious crust-mantle mixing characteristics.BA and DA reveal typical characteristics of island-arc magma systems and typeⅡenriched mantle(EM-Ⅱ)magma.BA magma was likely resulted from the process whereby the continental crust frontal accretionary wedge was driven by the Paleo-Pacific slab subduction into the deep and began to melt,resulting in a large amount of melt(fluid)joined the asthenosphere on the side of the continental margin.In contrast,DA magma was likely resulted from the process whereby the plate front was forced to bend with increasing subduction distance,which triggered
基金Acknowledgements The authors were grateful to the referees for their constructive comments and suggestions. This work was supported by the National Natural Science Foundation of China （Grant No. 11371109） and the Education Department of Heilongjiang Province of China （No. 12541605）.
文摘Abstract We first consider the group inverses of the block matrices（AB0C）over a weakly finite ring. Then we study the sufficient and necessary conditions for the existence and the representations of the group inverses of the block matrices（ABCD）over a ring with unity 1 under the following conditions respectively： （i） B = C, D = 0,B#and（BπA0#both exist; （ii） B is invertible and m = n;（iii）A#and （D - CA#B）# both exist, C = CAA#, where A and D are m × m and n × n matrices, respectively.
文摘Fast algorithms for reducing encoding complexity of fractal image coding have recently been an important research topic. Search of the best matched domain block is the most computation intensive part of the fractal encoding process. In this paper, a fast fractal approximation coding scheme implemented on a personal computer based on matching in range block's neighbours is presented.Experimental results show that the proposed algorithm is very simple in implementation, fast in encoding time and high in compression ratio while PSNR is almost the same as compared with Barnsley's fractal block coding .
基金funded by the Public Welfare Technology Research Project of Zhejiang Province(Grant No.LGF21F020014)the Opening Project ofKey Laboratory of Public Security Information Application Based on Big-Data Architecture,Ministry of Public Security of Zhejiang Police College(Grant No.2021DSJSYS002).
文摘Ceramic tiles are one of the most indispensable materials for interior decoration.The ceramic patterns can’t match the design requirements in terms of diversity and interactivity due to their natural textures.In this paper,we propose a sketch-based generation method for generating diverse ceramic tile images based on a hand-drawn sketches using Generative Adversarial Network(GAN).The generated tile images can be tailored to meet the specific needs of the user for the tile textures.The proposed method consists of four steps.Firstly,a dataset of ceramic tile images with diverse distributions is created and then pre-trained based on GAN.Secondly,for each ceramic tile image in the dataset,the corresponding sketch image is generated and then the mapping relationship between the images is trained based on a sketch extraction network using ResNet Block and jump connection to improve the quality of the generated sketches.Thirdly,the sketch style is redefined according to the characteristics of the ceramic tile images and then double cross-domain adversarial loss functions are employed to guide the ceramic tile generation network for fitting in the direction of the sketch style and to improve the training speed.Finally,we apply hidden space perturbation and interpolation for further enriching the output textures style and satisfying the concept of“one style with multiple faces”.We conduct the training process of the proposed generation network on 2583 ceramic tile images dataset.To measure the generative diversity and quality,we use Frechet Inception Distance(FID)and Blind/Referenceless Image Spatial Quality Evaluator(BRISQUE)metrics.The experimental results prove that the proposed model greatly enhances the generation results of the ceramic tile images,with FID of 32.47 and BRISQUE of 28.44.
