High-speed ophthalmic optical coherence tomography(OCT)systems are of interest because they allow rapid,motion-free,and wide-field retinal imaging.Space-division multiplexing optical coherence tomography(SDMOCT)is a h...High-speed ophthalmic optical coherence tomography(OCT)systems are of interest because they allow rapid,motion-free,and wide-field retinal imaging.Space-division multiplexing optical coherence tomography(SDMOCT)is a high-speed imaging technology that takes advantage of the long coherence length of micro electro mechanical vertical cavity surface emitting laser sources to multiplex multiple images along a single imaging depth.We demonstrate wide-field retinal OCT imaging,acquired at an effective A-scan rate of 800,000 A-scans/s with volumetric images covering up to 12.5 mm×7.4 mm on the retina and captured in less than 1 s.A clinical feasibility study was conducted to compare the ophthalmic SDM-OCT with commercial OCT systems,illustrating the high-speed capability of SDM-OCT in a clinical setting.展开更多
This paper develops a wide-band multi-spectral space for color representationwith Aitken PCA algorithm. This novel mathematical space using the broad-band spectra matchingmethod aims at improving the accuracy of color...This paper develops a wide-band multi-spectral space for color representationwith Aitken PCA algorithm. This novel mathematical space using the broad-band spectra matchingmethod aims at improving the accuracy of color representation as well as reducing costs forprocessing and storing multi-spectral images. The results show that the space can present ourexperimental original spectral spaces (i. e. Munsell color matt and DIN-6164 color chips) with highefficiency, and that the spanning space with three eigenvectors can present the original space atmore than 98% CSCR, and when 5 eigenvectors are used it can cover almost the whole o-riginal spaces.展开更多
High Resolution Wide Swath (HRWS) Synthetic Aperture Radar (SAR) often suffers from low Signal-to-Noise Ratio (SNR) due to small transmitting antenna, especially in phased array antenna systems. Digital Beam Forming (...High Resolution Wide Swath (HRWS) Synthetic Aperture Radar (SAR) often suffers from low Signal-to-Noise Ratio (SNR) due to small transmitting antenna, especially in phased array antenna systems. Digital Beam Forming (DBF) based on Single Input and Multiple Output (SIMO) achieves receiving array gain at the cost of increasing data rate. This letter proposes a new HRWS SAR method, which employs intra-pulse null steering to get receiving gain in elevation and decrease the data rate, and Multiple Input and Multiple Output (MIMO) using Space-Time Block Coding (STBC) in azimuth to get transmitting gain and receiving array gain simultaneously. The feasibility is verified by deduction and simulations.展开更多
In this paper, an asymmetric array structure of space laser communication receiver is proposed. This structure can greatly reduce alignment requirement, and lighten the signal strength jitter caused by atmospheric tur...In this paper, an asymmetric array structure of space laser communication receiver is proposed. This structure can greatly reduce alignment requirement, and lighten the signal strength jitter caused by atmospheric turbulence. A prototype of the proposed structure is fabricated and a 2.5 Mbit/s on-off keying(OOK) modulated demonstration link over 40 m free space is built. This asymmetric array structure can effectively collect optical signal while rotating in a window angle of ±17°, and the bit error ratio(BER) keeps zero.展开更多
In order to explore the interaction effects of line spacing and seedling belt width on wheat yield formation and improve the cultivation techniques of broadwidth and fine seeding of wheat,a high-yielding winter wheat ...In order to explore the interaction effects of line spacing and seedling belt width on wheat yield formation and improve the cultivation techniques of broadwidth and fine seeding of wheat,a high-yielding winter wheat cultivar Shannong 28 was selected as material. Using the split plot design,the main plot was set with line spacing as 20,25 and 30 cm,respectively,and the sub-plot was set with seedling belt width as 3,5,7,9 and 11 cm,respectively. Then,the population dynamics,dry matter accumulation and translocation and yield of wheat were studied under the experimental conditions. The results showed that under the line spacing of 20 cm,the dry matter accumulation and yield of winter wheat were higher with the seedling belt width of 5 cm. When the line spacing was 25 cm,the dry matter accumulation and yield under the seedling belt width of 9 cm reached a high level. Under the line spacing of 30 cm,Shannong 28 achieved higher dry matter accumulation and yield with the seedling belt width of 11 cm. Comprehensive analysis revealed that the suitable treatment for Shannong 28 was 25 cm of line spacing with 9 cm of seedling belt width,which could realize the coordination of the three factors of yield composition and get higher yield. Therefore,the reasonable line spacing and seedling belt width were the important technical ways to realize high yield of wheat.展开更多
基金National Science Foundation(DBI-1455613,IIP-1623823,IIP-1640707)National Institutes of Health(R01-EB025209)。
文摘High-speed ophthalmic optical coherence tomography(OCT)systems are of interest because they allow rapid,motion-free,and wide-field retinal imaging.Space-division multiplexing optical coherence tomography(SDMOCT)is a high-speed imaging technology that takes advantage of the long coherence length of micro electro mechanical vertical cavity surface emitting laser sources to multiplex multiple images along a single imaging depth.We demonstrate wide-field retinal OCT imaging,acquired at an effective A-scan rate of 800,000 A-scans/s with volumetric images covering up to 12.5 mm×7.4 mm on the retina and captured in less than 1 s.A clinical feasibility study was conducted to compare the ophthalmic SDM-OCT with commercial OCT systems,illustrating the high-speed capability of SDM-OCT in a clinical setting.
基金rojectsupportedbytheNationalNaturalScienceFoundationofChina (No .60 1 770 0 5) .
文摘This paper develops a wide-band multi-spectral space for color representationwith Aitken PCA algorithm. This novel mathematical space using the broad-band spectra matchingmethod aims at improving the accuracy of color representation as well as reducing costs forprocessing and storing multi-spectral images. The results show that the space can present ourexperimental original spectral spaces (i. e. Munsell color matt and DIN-6164 color chips) with highefficiency, and that the spanning space with three eigenvectors can present the original space atmore than 98% CSCR, and when 5 eigenvectors are used it can cover almost the whole o-riginal spaces.
文摘High Resolution Wide Swath (HRWS) Synthetic Aperture Radar (SAR) often suffers from low Signal-to-Noise Ratio (SNR) due to small transmitting antenna, especially in phased array antenna systems. Digital Beam Forming (DBF) based on Single Input and Multiple Output (SIMO) achieves receiving array gain at the cost of increasing data rate. This letter proposes a new HRWS SAR method, which employs intra-pulse null steering to get receiving gain in elevation and decrease the data rate, and Multiple Input and Multiple Output (MIMO) using Space-Time Block Coding (STBC) in azimuth to get transmitting gain and receiving array gain simultaneously. The feasibility is verified by deduction and simulations.
基金supported by the National Natural Science Foundation of China (Nos.61674142 and 62041502)。
文摘In this paper, an asymmetric array structure of space laser communication receiver is proposed. This structure can greatly reduce alignment requirement, and lighten the signal strength jitter caused by atmospheric turbulence. A prototype of the proposed structure is fabricated and a 2.5 Mbit/s on-off keying(OOK) modulated demonstration link over 40 m free space is built. This asymmetric array structure can effectively collect optical signal while rotating in a window angle of ±17°, and the bit error ratio(BER) keeps zero.
基金Supported by National Key R&D Program of China (2017YFD0301001)Shandong Province Modern Agricultural Technology Wheat Innovation Team (SDAIT-04-022+1 种基金SDAIT-01-08)Agricultural Scientific and Technological Innovation project of Shandong Academy of Agricultural Sciences (CXGC2016B01)。
文摘In order to explore the interaction effects of line spacing and seedling belt width on wheat yield formation and improve the cultivation techniques of broadwidth and fine seeding of wheat,a high-yielding winter wheat cultivar Shannong 28 was selected as material. Using the split plot design,the main plot was set with line spacing as 20,25 and 30 cm,respectively,and the sub-plot was set with seedling belt width as 3,5,7,9 and 11 cm,respectively. Then,the population dynamics,dry matter accumulation and translocation and yield of wheat were studied under the experimental conditions. The results showed that under the line spacing of 20 cm,the dry matter accumulation and yield of winter wheat were higher with the seedling belt width of 5 cm. When the line spacing was 25 cm,the dry matter accumulation and yield under the seedling belt width of 9 cm reached a high level. Under the line spacing of 30 cm,Shannong 28 achieved higher dry matter accumulation and yield with the seedling belt width of 11 cm. Comprehensive analysis revealed that the suitable treatment for Shannong 28 was 25 cm of line spacing with 9 cm of seedling belt width,which could realize the coordination of the three factors of yield composition and get higher yield. Therefore,the reasonable line spacing and seedling belt width were the important technical ways to realize high yield of wheat.
