The correct rate of detection for fabric defect is affected by low contrast of images. Aiming at the problem,frequencytuned salient map is used to detect the fabric defect. Firstly,the images of fabric defect are divi...The correct rate of detection for fabric defect is affected by low contrast of images. Aiming at the problem,frequencytuned salient map is used to detect the fabric defect. Firstly,the images of fabric defect are divided into blocks. Then,the blocks are highlighted by frequency-tuned salient algorithm. Simultaneously,gray-level co-occurrence matrix is used to extract the characteristic value of each rectangular patch. Finally,PNN is used to detect the defect on the fabric image. The performance of proposed algorithm is estimated off-line by two sets of fabric defect images. The theoretical argument is supported by experimental results.展开更多
We report a method to tune the second harmonic generation(SHG) frequency of a metallic octamer by employing cylindrical vector beams as the excitation. Our method exploits the ability to spatially match the polarizati...We report a method to tune the second harmonic generation(SHG) frequency of a metallic octamer by employing cylindrical vector beams as the excitation. Our method exploits the ability to spatially match the polarization state of excitations with the fundamental target plasmonic modes, enabling flexible control of the SHG resonant frequency.It is found that SHG of the octamer is enhanced over a broad band(400 nm) by changing the excitation from the linearly polarized Gaussian beam to radially and azimuthally polarized beams. More strikingly, when subjected to an azimuthally polarized beam, the SHG intensity of the octamer becomes 30 times stronger than that for the linearly polarized beam even in the presence of Fano resonance.展开更多
Since the discovery of high temperature superconducting(HTS)materials in 1987,the performance of microwave filters such as insertion loss,selectivity,and out-band rejection has been significantly improved by utilizing...Since the discovery of high temperature superconducting(HTS)materials in 1987,the performance of microwave filters such as insertion loss,selectivity,and out-band rejection has been significantly improved by utilizing HTS films.Nowadays,HTS filters have been widely used in wireless communications,space exploration,satellite communications,and several other fields.HTS filters with a special performance,such as wideband,dual-band or multiband,frequency tunable,and high power-handling capability have been designed and fabricated in recent years to meet the increasing requirements of practical applications and to further extend the application areas.This paper reviews the various types of above-mentioned HTS filters as well as the developments of novel design methodologies.展开更多
文摘The correct rate of detection for fabric defect is affected by low contrast of images. Aiming at the problem,frequencytuned salient map is used to detect the fabric defect. Firstly,the images of fabric defect are divided into blocks. Then,the blocks are highlighted by frequency-tuned salient algorithm. Simultaneously,gray-level co-occurrence matrix is used to extract the characteristic value of each rectangular patch. Finally,PNN is used to detect the defect on the fabric image. The performance of proposed algorithm is estimated off-line by two sets of fabric defect images. The theoretical argument is supported by experimental results.
基金National Key R&D Program of China(2017YFA0303800)National Natural Science Foundation of China(NSFC)(11634010,51777168,61377035,61675170,61675171,61701303)+4 种基金Australian Research Council(ARC)(DP140100883)Natural Science Basic Research Plan in Shaanxi Province,China(2017JM6022)Fundamental Research Funds for the Central Universities,China(3102017zy017)Natural Science Foundation of Shanghai,China(17ZR1414300)Shanghai Pujiang Program,China(17PJ1404100)
文摘We report a method to tune the second harmonic generation(SHG) frequency of a metallic octamer by employing cylindrical vector beams as the excitation. Our method exploits the ability to spatially match the polarization state of excitations with the fundamental target plasmonic modes, enabling flexible control of the SHG resonant frequency.It is found that SHG of the octamer is enhanced over a broad band(400 nm) by changing the excitation from the linearly polarized Gaussian beam to radially and azimuthally polarized beams. More strikingly, when subjected to an azimuthally polarized beam, the SHG intensity of the octamer becomes 30 times stronger than that for the linearly polarized beam even in the presence of Fano resonance.
基金supported in part by the Key-Area Research and Development Program of Guangdong Province under Grant 2020B0101340002in part by the National Nature Science Foundation of China under Grants 61971415 and 61601456supported by the Youth Innovation Promotion Association of CAS under Grants Y2021004 and 2017009.
文摘Since the discovery of high temperature superconducting(HTS)materials in 1987,the performance of microwave filters such as insertion loss,selectivity,and out-band rejection has been significantly improved by utilizing HTS films.Nowadays,HTS filters have been widely used in wireless communications,space exploration,satellite communications,and several other fields.HTS filters with a special performance,such as wideband,dual-band or multiband,frequency tunable,and high power-handling capability have been designed and fabricated in recent years to meet the increasing requirements of practical applications and to further extend the application areas.This paper reviews the various types of above-mentioned HTS filters as well as the developments of novel design methodologies.
