The quality of maize seeds affects the outcome of planting and harvesting,so seed quality inspection has become very important.Traditional seed quality detection methods are labor-intensive and time-consuming,whereas ...The quality of maize seeds affects the outcome of planting and harvesting,so seed quality inspection has become very important.Traditional seed quality detection methods are labor-intensive and time-consuming,whereas seed quality detection using computer vision techniques is efficient and accurate.In this study,we conducted migration learning training in AlexNet,VGG11 and ShuffleNetV2 network models respectively,and found that ShuffleNetV2 has a high accuracy rate for maize seed classification and recognition by comparing various metrics.In this study,the features of the seed images were extracted through image pre-processing methods,and then the AlexNet,VGG11 and ShuffleNetV2 models were used for training and classification respectively.A total of 2081 seed images containing four varieties were used for training and testing.The experimental results showed that ShuffleNetV2 could efficiently distinguish different varieties of maize seeds with the highest classification accuracy of 100%,where the parameter size of the model was at 20.65 MB and the response time for a single image was at 0.45 s.Therefore,the method is of high practicality and extension value.展开更多
The self-focusing phenomenon of partially coherent beams(PCBs)was simulated using the complex screen method combined with the split-step Fourier method to solve the nonlinear Schrödinger equation.Considering the ...The self-focusing phenomenon of partially coherent beams(PCBs)was simulated using the complex screen method combined with the split-step Fourier method to solve the nonlinear Schrödinger equation.Considering the propagation of Gaussian Schell-model beams in a nonlinear medium as an example,the suppression effects of intensity,propagation distance,and spatial coherence on small-scale self-focusing were demonstrated.Simulations of overall and small-scale self-focusing using this method were compared with the existing literature to demonstrate the validity of the method.This method can numerically analyze the degree of self-focusing in PCBs and advance the study of their nonlinearity.展开更多
In this paper, we review the status of the multifunctional experimental platform at the National Laboratory of High Power Laser and Physics(NLHPLP). The platform, including the SG-II laser facility, SG-II 9th beam, SG...In this paper, we review the status of the multifunctional experimental platform at the National Laboratory of High Power Laser and Physics(NLHPLP). The platform, including the SG-II laser facility, SG-II 9th beam, SG-II upgrade(SG-II UP) facility, and SG-II 5 PW facility, is operational and available for interested scientists studying inertial confinement fusion(ICF) and a broad range of high-energy-density physics. These facilities can provide important experimental capabilities by combining different pulse widths of nanosecond, picosecond, and femtosecond scales. In addition, the SG-II UP facility, consisting of a single petawatt system and an eight-beam nanosecond system, is introduced including several laser technologies that have been developed to ensure the performance of the facility. Recent developments of the SG-II 5 PW facility are also presented.展开更多
Understanding the role of agriculture in the development of human societies around the world is an important field of study with many unanswered questions.As a step toward that greater understanding,we have studied th...Understanding the role of agriculture in the development of human societies around the world is an important field of study with many unanswered questions.As a step toward that greater understanding,we have studied the archeobotanical remains at the Jingshuidun site in the mountainous areas of the lower reaches of the Yangtze River in southern Anhui Province which are part of the core area of rice cultivation today.Our analyses of macrobotanical remains and phytoliths formed the basis for the reconstruction of the subsistence economy of ancient humans at the Jingshuidun site from the late Neolithic to early historical times.When our data are combined with that of previous archeobotanical work,we obtain a clearer picture of the development of rice and millet agriculture in the southern Anhui Province region,as well as the spread of millet cultivation.Macrobotanical remains and phytoliths of domesticated rice are present in layers at the Jingshuidun site dated to 4874–4820 cal.yr B.P.(middle-late Liangzhu Period)and 2667–2568 cal.yr B.P.(late Western Zhou Dynasty to the early Spring and Autumn Period).Moreover,macrobotanical remains and phytoliths from the site document the earliest remains of foxtail millet(Setaria italica)in southern Anhui Province,from a layer dating to the late Western Zhou Dynasty and the early Spring and Autumn Period(2667–2568 cal.yr B.P.).These results suggest that the people occupying the Jingshuidun site used single rice farming as far back as 4874–4820 cal.yr B.P.,and they began to plant millet by at least 2667–2568 cal.yr B.P.,documenting the spread of millet agriculture to the southern area by that time.展开更多
The intensity distributions of a high-power broadband laser beam passing through a nonlinear optical medium with defects and then propagating in free space are investigated based on the general nonlinear Schr¨odi...The intensity distributions of a high-power broadband laser beam passing through a nonlinear optical medium with defects and then propagating in free space are investigated based on the general nonlinear Schr¨odinger equation and the split-step Fourier numerical method. The influences of the bandwidth of the laser beam, the thickness of the medium,and the defects on the light intensity distribution are revealed. We find that the nonlinear optical effect can be suppressed and that the uniformity of the beam can be improved for a high-power broadband laser beam with appropriate wide bandwidth. It is also found that, under the same incident light intensity, a thicker medium will lead to a stronger self-focusing intensity, and that the influence of defects in the optical elements on the intensity is stronger for a narrowband beam than for a broadband beam.展开更多
文摘The quality of maize seeds affects the outcome of planting and harvesting,so seed quality inspection has become very important.Traditional seed quality detection methods are labor-intensive and time-consuming,whereas seed quality detection using computer vision techniques is efficient and accurate.In this study,we conducted migration learning training in AlexNet,VGG11 and ShuffleNetV2 network models respectively,and found that ShuffleNetV2 has a high accuracy rate for maize seed classification and recognition by comparing various metrics.In this study,the features of the seed images were extracted through image pre-processing methods,and then the AlexNet,VGG11 and ShuffleNetV2 models were used for training and classification respectively.A total of 2081 seed images containing four varieties were used for training and testing.The experimental results showed that ShuffleNetV2 could efficiently distinguish different varieties of maize seeds with the highest classification accuracy of 100%,where the parameter size of the model was at 20.65 MB and the response time for a single image was at 0.45 s.Therefore,the method is of high practicality and extension value.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA25020203 and 25020301)the Innovation Fund of the Key Laboratory of the Chinese Academy of Sciences(No.CXJJ-21S015)。
文摘The self-focusing phenomenon of partially coherent beams(PCBs)was simulated using the complex screen method combined with the split-step Fourier method to solve the nonlinear Schrödinger equation.Considering the propagation of Gaussian Schell-model beams in a nonlinear medium as an example,the suppression effects of intensity,propagation distance,and spatial coherence on small-scale self-focusing were demonstrated.Simulations of overall and small-scale self-focusing using this method were compared with the existing literature to demonstrate the validity of the method.This method can numerically analyze the degree of self-focusing in PCBs and advance the study of their nonlinearity.
基金supported by International Partnership Program of Chinese Academy of Sciences(No.181231KYSB20170022)the Key Projects of International Cooperation in Chinese Academy of Sciences
文摘In this paper, we review the status of the multifunctional experimental platform at the National Laboratory of High Power Laser and Physics(NLHPLP). The platform, including the SG-II laser facility, SG-II 9th beam, SG-II upgrade(SG-II UP) facility, and SG-II 5 PW facility, is operational and available for interested scientists studying inertial confinement fusion(ICF) and a broad range of high-energy-density physics. These facilities can provide important experimental capabilities by combining different pulse widths of nanosecond, picosecond, and femtosecond scales. In addition, the SG-II UP facility, consisting of a single petawatt system and an eight-beam nanosecond system, is introduced including several laser technologies that have been developed to ensure the performance of the facility. Recent developments of the SG-II 5 PW facility are also presented.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB26000000)the National Natural Science Foundation of China(Grant No.41877427)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2018099)。
文摘Understanding the role of agriculture in the development of human societies around the world is an important field of study with many unanswered questions.As a step toward that greater understanding,we have studied the archeobotanical remains at the Jingshuidun site in the mountainous areas of the lower reaches of the Yangtze River in southern Anhui Province which are part of the core area of rice cultivation today.Our analyses of macrobotanical remains and phytoliths formed the basis for the reconstruction of the subsistence economy of ancient humans at the Jingshuidun site from the late Neolithic to early historical times.When our data are combined with that of previous archeobotanical work,we obtain a clearer picture of the development of rice and millet agriculture in the southern Anhui Province region,as well as the spread of millet cultivation.Macrobotanical remains and phytoliths of domesticated rice are present in layers at the Jingshuidun site dated to 4874–4820 cal.yr B.P.(middle-late Liangzhu Period)and 2667–2568 cal.yr B.P.(late Western Zhou Dynasty to the early Spring and Autumn Period).Moreover,macrobotanical remains and phytoliths from the site document the earliest remains of foxtail millet(Setaria italica)in southern Anhui Province,from a layer dating to the late Western Zhou Dynasty and the early Spring and Autumn Period(2667–2568 cal.yr B.P.).These results suggest that the people occupying the Jingshuidun site used single rice farming as far back as 4874–4820 cal.yr B.P.,and they began to plant millet by at least 2667–2568 cal.yr B.P.,documenting the spread of millet agriculture to the southern area by that time.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.61178015 and 11304104the Open Research Fund of the National Laboratory on High Power Laser and Physics under Grant No.SG-001102
文摘The intensity distributions of a high-power broadband laser beam passing through a nonlinear optical medium with defects and then propagating in free space are investigated based on the general nonlinear Schr¨odinger equation and the split-step Fourier numerical method. The influences of the bandwidth of the laser beam, the thickness of the medium,and the defects on the light intensity distribution are revealed. We find that the nonlinear optical effect can be suppressed and that the uniformity of the beam can be improved for a high-power broadband laser beam with appropriate wide bandwidth. It is also found that, under the same incident light intensity, a thicker medium will lead to a stronger self-focusing intensity, and that the influence of defects in the optical elements on the intensity is stronger for a narrowband beam than for a broadband beam.
