Vortex beam with fractional orbital angular momentum (FOAM) is the excellent candidate for improving the capacity of free-space optical (FSO) communication system due to its infinite modes. Therefore, the recognition ...Vortex beam with fractional orbital angular momentum (FOAM) is the excellent candidate for improving the capacity of free-space optical (FSO) communication system due to its infinite modes. Therefore, the recognition of FOAM modes with higher resolution is always of great concern. In this work, through an improved EfficientNetV2 based convolutional neural network (CNN), we experimentally achieve the implementation of the recognition of FOAM modes with a resolution as high as 0.001. To the best of our knowledge, it is the first time this high resolution has been achieved. Under the strong atmospheric turbulence (AT) (C_(n)^(2)=10^(-15)m^(-2/3)), the recognition accuracy of FOAM modes at 0.1 and 0.01 resolution with our model is up to 99.12% and 92.24% for a long transmission distance of 2000 m. Even for the resolution at 0.001, the recognition accuracy can still remain at 78.77%. This work provides an effective method for the recognition of FOAM modes, which may largely improve the channel capacity of the free-space optical communication.展开更多
Rod-like ZnO particles were synthesized via a sol-gel method by adding ethylene diarnine （EDA） to the reaction system of Zn（Ac）2.2H2O and H2C2O4.2H2O. The crystal phase and morphology of the products were characte...Rod-like ZnO particles were synthesized via a sol-gel method by adding ethylene diarnine （EDA） to the reaction system of Zn（Ac）2.2H2O and H2C2O4.2H2O. The crystal phase and morphology of the products were characterized by XRD （X-ray powder diffractometer） and TEM （transmission electron microscope） Rod-like ZnO belongs to the hexagonal Wurtzite system, with diameters and lengths of about 20-200 nm and 0.2-1.5μm, respectively. Experimental results showed that the morphology of nano-ZnO can be controlled by modulating the quantities of EDA added into the reaction system and that EDA plays ar important role in the formation of rod-like ZnO particles. The growth mechanism of the rod-like nano- ZnO was briefly discussed. The proposed facile, reproducible, effective and low-cost synthesis promises future large-scale preparation of nanostructured ZnO for application in nanotechnology.展开更多
The evaluation of rock damage behaviour is an important requirement for ensuring stability control and safety prediction in rock engineering.However,they have not been able to obtain sufficiently accurate and dynamic ...The evaluation of rock damage behaviour is an important requirement for ensuring stability control and safety prediction in rock engineering.However,they have not been able to obtain sufficiently accurate and dynamic results due to the insufficient evaluation method.In this study,by means of fractals and unit series division,a unit series-parallel conductive model of damaged rock is derived,and a new evaluation method of rock damage under uniaxial compression was proposed.Rock was damaged by uniaxial compression,while electrical measurements and X-ray microscopy tests were performed to obtain the damaged rock resistivity,porosity,and fractal dimension variation.By establishing the relationship between defined meso-damage factor and resistivity,rock damage evolution law under axial compression was obtained.The results indicate that the growth trend was agree with the classical statistical damage model,which verified the accuracy of the results obtained by the proposed method.Moreover,as the strain increased,the damage factor determined by resistivity gradually decreased to0.06 firstly and then increased rapidly to 0.79.Different from previous damage evolution law,brittle failure was observed and the cracks development in each stage was considered,including the closure(negative damage)and expansion(positive damage)of cracks.展开更多
Plant AT-rich sequence and zinc binding(PLATZ)transcription factors are a class of plant specific zincdependent DNA-binding proteins that function in abiotic stress response and plant development.In this study,31 GmPL...Plant AT-rich sequence and zinc binding(PLATZ)transcription factors are a class of plant specific zincdependent DNA-binding proteins that function in abiotic stress response and plant development.In this study,31 GmPLATZ genes were identified in soybean.GmPLATZ17 was down-regulated by drought and exogenous abscisic acid.Transgenic Arabidopsis and soybean hairy roots overexpressing GmPLATZ17 showed drought sensitivity and inhibition of stress-associated gene transcription.In contrast,suppressed expression of GmPLATZ17 led to increased drought tolerance in transgenic soybean hairy roots.The GmPLATZ17 protein was verified to interact physically with the GmDREB5 transcription factor,and overexpression of GmDREB5 increased drought tolerance in soybean hairy roots.Interaction of GmPLATZ17 with GmDREB5 was shown to interfere with the DRE-binding activity of GmDREB5,suppressing downstream stress-associated gene expression.These results show that GmPLATZ17 inhibits drought tolerance by interacting with GmDREB5.This study sheds light on PLATZ transcription factors and the function of GmPLATZ17 in regulating drought sensitivity.展开更多
The Normalized Difference Vegetation Index （NDVI） is an important vegetation greenness indicator. Compared to the AVHRR GIMMS NDVI data, the availability of two datasets with 1 km spatial resolution, i.e., Terra MOD...The Normalized Difference Vegetation Index （NDVI） is an important vegetation greenness indicator. Compared to the AVHRR GIMMS NDVI data, the availability of two datasets with 1 km spatial resolution, i.e., Terra MODIS （MODI3A3） monthly composite and SPOT Vegetation （VGT） 10-day composite NDVI, extends the application dimensions at spatial and temporal scales. An overlapping period of 12 years between the datasets now makes it possible to investigate the consistency of the two datasets. Linear regression trend analysis was performed to compare the two datasets in this study. The results show greater consistency in regression slopes in the semi-arid regions of northern China. Alternatively, the results show only slight changes in the Terra MODIS NDVI regression slope in most areas of southern China whereas the SPOT VGT NDVI shows positive changes over a large area. The corresponding regression slope values between Terra MODIS and SPOT VGT NDVI datasets from the linear fit had a fair agreement in the spatial dimension. However, larger positive and negative differences were observed at the junction of the three regions （East China, Central China, and North China）. These differences can be partially explained by the positive standard deviation differences distributed over a large area at the junction of these three regions. This study demonstrated that Terra MODIS and SPOT VGT NDVI have a relatively robust basis for characterizing vegetation changes in annual NDVI in most of the semi-arid and arid regions in northern China.展开更多
基金the National Natural Science Foundation of China(Grant Nos.62271332,12374273,and 62275162)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030152)+1 种基金the Shenzhen Government’s Plan of Science and Technology(Nos.JCYJ20180305124927623 and JCYJ20190808150205481)the Training Program for Excellent Young innovators of Changsha(No.kq2107013).
文摘Vortex beam with fractional orbital angular momentum (FOAM) is the excellent candidate for improving the capacity of free-space optical (FSO) communication system due to its infinite modes. Therefore, the recognition of FOAM modes with higher resolution is always of great concern. In this work, through an improved EfficientNetV2 based convolutional neural network (CNN), we experimentally achieve the implementation of the recognition of FOAM modes with a resolution as high as 0.001. To the best of our knowledge, it is the first time this high resolution has been achieved. Under the strong atmospheric turbulence (AT) (C_(n)^(2)=10^(-15)m^(-2/3)), the recognition accuracy of FOAM modes at 0.1 and 0.01 resolution with our model is up to 99.12% and 92.24% for a long transmission distance of 2000 m. Even for the resolution at 0.001, the recognition accuracy can still remain at 78.77%. This work provides an effective method for the recognition of FOAM modes, which may largely improve the channel capacity of the free-space optical communication.
文摘Rod-like ZnO particles were synthesized via a sol-gel method by adding ethylene diarnine （EDA） to the reaction system of Zn（Ac）2.2H2O and H2C2O4.2H2O. The crystal phase and morphology of the products were characterized by XRD （X-ray powder diffractometer） and TEM （transmission electron microscope） Rod-like ZnO belongs to the hexagonal Wurtzite system, with diameters and lengths of about 20-200 nm and 0.2-1.5μm, respectively. Experimental results showed that the morphology of nano-ZnO can be controlled by modulating the quantities of EDA added into the reaction system and that EDA plays ar important role in the formation of rod-like ZnO particles. The growth mechanism of the rod-like nano- ZnO was briefly discussed. The proposed facile, reproducible, effective and low-cost synthesis promises future large-scale preparation of nanostructured ZnO for application in nanotechnology.
基金supported by Open Fund of State Key Laboratory of Frozen Soil Engineering (SKLFSE202115)the National Key R&D Program of China (2018YFC1504504).
文摘The evaluation of rock damage behaviour is an important requirement for ensuring stability control and safety prediction in rock engineering.However,they have not been able to obtain sufficiently accurate and dynamic results due to the insufficient evaluation method.In this study,by means of fractals and unit series division,a unit series-parallel conductive model of damaged rock is derived,and a new evaluation method of rock damage under uniaxial compression was proposed.Rock was damaged by uniaxial compression,while electrical measurements and X-ray microscopy tests were performed to obtain the damaged rock resistivity,porosity,and fractal dimension variation.By establishing the relationship between defined meso-damage factor and resistivity,rock damage evolution law under axial compression was obtained.The results indicate that the growth trend was agree with the classical statistical damage model,which verified the accuracy of the results obtained by the proposed method.Moreover,as the strain increased,the damage factor determined by resistivity gradually decreased to0.06 firstly and then increased rapidly to 0.79.Different from previous damage evolution law,brittle failure was observed and the cracks development in each stage was considered,including the closure(negative damage)and expansion(positive damage)of cracks.
基金supported by the National Natural Science Foundation of China(31871624)the Agricultural Science and Technology Innovation Program(CAAS-ZDRW202109 and CAAS-ZDRW202002)the Central Public-interest Scientific Institution Basal Research Fund.
文摘Plant AT-rich sequence and zinc binding(PLATZ)transcription factors are a class of plant specific zincdependent DNA-binding proteins that function in abiotic stress response and plant development.In this study,31 GmPLATZ genes were identified in soybean.GmPLATZ17 was down-regulated by drought and exogenous abscisic acid.Transgenic Arabidopsis and soybean hairy roots overexpressing GmPLATZ17 showed drought sensitivity and inhibition of stress-associated gene transcription.In contrast,suppressed expression of GmPLATZ17 led to increased drought tolerance in transgenic soybean hairy roots.The GmPLATZ17 protein was verified to interact physically with the GmDREB5 transcription factor,and overexpression of GmDREB5 increased drought tolerance in soybean hairy roots.Interaction of GmPLATZ17 with GmDREB5 was shown to interfere with the DRE-binding activity of GmDREB5,suppressing downstream stress-associated gene expression.These results show that GmPLATZ17 inhibits drought tolerance by interacting with GmDREB5.This study sheds light on PLATZ transcription factors and the function of GmPLATZ17 in regulating drought sensitivity.
文摘The Normalized Difference Vegetation Index （NDVI） is an important vegetation greenness indicator. Compared to the AVHRR GIMMS NDVI data, the availability of two datasets with 1 km spatial resolution, i.e., Terra MODIS （MODI3A3） monthly composite and SPOT Vegetation （VGT） 10-day composite NDVI, extends the application dimensions at spatial and temporal scales. An overlapping period of 12 years between the datasets now makes it possible to investigate the consistency of the two datasets. Linear regression trend analysis was performed to compare the two datasets in this study. The results show greater consistency in regression slopes in the semi-arid regions of northern China. Alternatively, the results show only slight changes in the Terra MODIS NDVI regression slope in most areas of southern China whereas the SPOT VGT NDVI shows positive changes over a large area. The corresponding regression slope values between Terra MODIS and SPOT VGT NDVI datasets from the linear fit had a fair agreement in the spatial dimension. However, larger positive and negative differences were observed at the junction of the three regions （East China, Central China, and North China）. These differences can be partially explained by the positive standard deviation differences distributed over a large area at the junction of these three regions. This study demonstrated that Terra MODIS and SPOT VGT NDVI have a relatively robust basis for characterizing vegetation changes in annual NDVI in most of the semi-arid and arid regions in northern China.
