An increase in crop intensity could improve crop yield but may also lead to a series of environmental problems, such as depletion of ground water and increased soil salinity. The generation of high resolution(30 m) cr...An increase in crop intensity could improve crop yield but may also lead to a series of environmental problems, such as depletion of ground water and increased soil salinity. The generation of high resolution(30 m) crop intensity maps is an important method used to monitor these changes, but this is challenging because the temporal resolution of the 30-m image time series is low due to the long satellite revisit period and high cloud coverage. The recently launched Sentinel-2 satellite could provide optical images at 10–60 m resolution and thus improve the temporal resolution of the 30-m image time series. This study used harmonized Landsat Sentinel-2(HLS) data to identify crop intensity. The sixth polynomial function was used to fit the normalized difference vegetation index(NDVI) and enhanced vegetation index(EVI) curves. Then, 15-day NDVI and EVI time series were then generated from the fitted curves and used to generate the extent of croplands. Lastly, the first derivative of the fitted VI curves were used to calculate the VI peaks;spurious peaks were removed using artificially defined thresholds and crop intensity was generated by counting the number of remaining VI peaks. The proposed methods were tested in four study regions, with results showing that 15-day time series generated from the fitted curves could accurately identify cropland extent. Overall accuracy of cropland identification was higher than 95%. In addition, both the harmonized NDVI and EVI time series identified crop intensity accurately as the overall accuracies, producer’s accuracies and user’s accuracies of non-cropland, single crop cycle and double crop cycle were higher than 85%. NDVI outperformed EVI as identifying double crop cycle fields more accurately.展开更多
In recent years,primary energy consumption in China’s urban areas has increased rapidly,facing the problems of extensive use of energy,high energy consumption and insufficient intensified use of energy resources.Impr...In recent years,primary energy consumption in China’s urban areas has increased rapidly,facing the problems of extensive use of energy,high energy consumption and insufficient intensified use of energy resources.Improving multienergy supply,increasing the proportion of clean energy and integrated energy efficiency are the main goals of urban development.The integrated energy system with multi-functional synergy and open trading will become one of the new directions for the development of new urban energy systems.This paper summarizes the main problems faced by the current towns and the characteristics of the new urban energy system,analyzes the development of new urban energy system from three aspects including energy interconnection hub infrastructure construction,energy management platform construction and energy value sharing,and forecasts the future development direction of new urban energy systems.展开更多
In this experiment,male and female of the ICRstrain were used and were injected intraperitoneallywith different dose of iodine-125.The percentage ofabnormal sperm of male mice,the rate of primaryoocyte survival of fem...In this experiment,male and female of the ICRstrain were used and were injected intraperitoneallywith different dose of iodine-125.The percentage ofabnormal sperm of male mice,the rate of primaryoocyte survival of female mice,and the change ofradioactive intensity in testicle and ovary afterinjection of iodine-125 were studied.Our展开更多
To evaluate the effects of left ventricular contractility on the changes of aver age image intensity (AII) of the myocardial integrated backscatter (IB) and cyclic variation in IB (CVIB), 7 adult mongrel dogs were stu...To evaluate the effects of left ventricular contractility on the changes of aver age image intensity (AII) of the myocardial integrated backscatter (IB) and cyclic variation in IB (CVIB), 7 adult mongrel dogs were studied. The magnitude of AII and CVIB were measured from myocardial IB carves before and after dobuta mine or propranolol infusion. Dobutamine or propranolol did not affect the magnitude of AII (13.8±0.7 vs 14.7±0.5, P >0.05 or 14.3±0.5 vs 14.2±0.4, P >0.05). However, dobutamine produced a significant increase in the magnitude of CVIB (6.8±0.3 vs 9.5±0.6, P <0.001) and propranolol induced significant decrease in the magnitude of CVIB (7.1±0.2 vs 5.2±0.3, P <0.001). The changes of the magnitude of AII and CVIB in the myocardium have been demonstrated to reflect different myocardial physiological and pathological changes respectively. The alteration of contractility did not affect the magnitude of AII but induced significant change in CVIB. The increase of left ventricular contractility res ulted in a significant rise of the magnitude of CVIB and the decrease of left ventricular contractility resulted in a significant fall of the magnitude of CVIB.展开更多
The possible existence of neutrino astronomical objects (NAO) arouses great interests in the transparent gravitational lenses. The basic equations of gravitational lenses have already been obtained. In this note we sh...The possible existence of neutrino astronomical objects (NAO) arouses great interests in the transparent gravitational lenses. The basic equations of gravitational lenses have already been obtained. In this note we shall deduce the location and the number of the images of a star produced by a spherically展开更多
Nuclear magnetic resonance (NMR) spectra are usually measured either by continuous wave (CW) method or by pulse Fouries transform (PFT) method.Total or part spectra measured by CW method are undistorted, but the sensi...Nuclear magnetic resonance (NMR) spectra are usually measured either by continuous wave (CW) method or by pulse Fouries transform (PFT) method.Total or part spectra measured by CW method are undistorted, but the sensitivity is lower.展开更多
According to the No. 14 proclamation issued by Customs Service, as from April 1st 2007, the importation of galena and the lead ore concentrate will enjoy the favorable policy intended for associated gold deposits, i.e...According to the No. 14 proclamation issued by Customs Service, as from April 1st 2007, the importation of galena and the lead ore concentrate will enjoy the favorable policy intended for associated gold deposits, i.e. the value-added tax for gold component in the imported galena and lead ore concentrate is exempted,展开更多
On June 8th,Liaoning Chengda Co.,Ltd.(SH: 600739) announced todevelop oil shale resources in Xinjiang region.The company has signeda letter of intend with Xinjiang Baoming Mine Co.,Ltd.Xinjiang Baoming Mine has four l...On June 8th,Liaoning Chengda Co.,Ltd.(SH: 600739) announced todevelop oil shale resources in Xinjiang region.The company has signeda letter of intend with Xinjiang Baoming Mine Co.,Ltd.Xinjiang Baoming Mine has four licenses for oil shale explorationwith a total exploration area of 70.24 square kilometers.Under the initial agreement,Liaoning Chengda will purchase a 60%stake of Xinjiang Baoming,making it a joint venture.展开更多
With the ever intense competition in sports,higher requirements are placed not only on athletes but also on professional sports equip-ments as well.Carbon fiber with
基金supported by the China Postdoctoral Science Foundation (2017M620075 and BX201700286)the National Natural Science Foundation of China (NSFC-61661136006)
文摘An increase in crop intensity could improve crop yield but may also lead to a series of environmental problems, such as depletion of ground water and increased soil salinity. The generation of high resolution(30 m) crop intensity maps is an important method used to monitor these changes, but this is challenging because the temporal resolution of the 30-m image time series is low due to the long satellite revisit period and high cloud coverage. The recently launched Sentinel-2 satellite could provide optical images at 10–60 m resolution and thus improve the temporal resolution of the 30-m image time series. This study used harmonized Landsat Sentinel-2(HLS) data to identify crop intensity. The sixth polynomial function was used to fit the normalized difference vegetation index(NDVI) and enhanced vegetation index(EVI) curves. Then, 15-day NDVI and EVI time series were then generated from the fitted curves and used to generate the extent of croplands. Lastly, the first derivative of the fitted VI curves were used to calculate the VI peaks;spurious peaks were removed using artificially defined thresholds and crop intensity was generated by counting the number of remaining VI peaks. The proposed methods were tested in four study regions, with results showing that 15-day time series generated from the fitted curves could accurately identify cropland extent. Overall accuracy of cropland identification was higher than 95%. In addition, both the harmonized NDVI and EVI time series identified crop intensity accurately as the overall accuracies, producer’s accuracies and user’s accuracies of non-cropland, single crop cycle and double crop cycle were higher than 85%. NDVI outperformed EVI as identifying double crop cycle fields more accurately.
基金supported by National Key R&D Program of China (No. 2018YFB0905000)Science and Technology Project of SGCC (SGTJDK00DWJS1800232)+1 种基金National Natural Science Foundation of China (51977141)State Grid Corporation of China project: “Research on Construction Technology of Integrated Energy System for Urban Multifunctional Groups” (SGTJJY00GHJS1900040)
文摘In recent years,primary energy consumption in China’s urban areas has increased rapidly,facing the problems of extensive use of energy,high energy consumption and insufficient intensified use of energy resources.Improving multienergy supply,increasing the proportion of clean energy and integrated energy efficiency are the main goals of urban development.The integrated energy system with multi-functional synergy and open trading will become one of the new directions for the development of new urban energy systems.This paper summarizes the main problems faced by the current towns and the characteristics of the new urban energy system,analyzes the development of new urban energy system from three aspects including energy interconnection hub infrastructure construction,energy management platform construction and energy value sharing,and forecasts the future development direction of new urban energy systems.
文摘In this experiment,male and female of the ICRstrain were used and were injected intraperitoneallywith different dose of iodine-125.The percentage ofabnormal sperm of male mice,the rate of primaryoocyte survival of female mice,and the change ofradioactive intensity in testicle and ovary afterinjection of iodine-125 were studied.Our
文摘To evaluate the effects of left ventricular contractility on the changes of aver age image intensity (AII) of the myocardial integrated backscatter (IB) and cyclic variation in IB (CVIB), 7 adult mongrel dogs were studied. The magnitude of AII and CVIB were measured from myocardial IB carves before and after dobuta mine or propranolol infusion. Dobutamine or propranolol did not affect the magnitude of AII (13.8±0.7 vs 14.7±0.5, P >0.05 or 14.3±0.5 vs 14.2±0.4, P >0.05). However, dobutamine produced a significant increase in the magnitude of CVIB (6.8±0.3 vs 9.5±0.6, P <0.001) and propranolol induced significant decrease in the magnitude of CVIB (7.1±0.2 vs 5.2±0.3, P <0.001). The changes of the magnitude of AII and CVIB in the myocardium have been demonstrated to reflect different myocardial physiological and pathological changes respectively. The alteration of contractility did not affect the magnitude of AII but induced significant change in CVIB. The increase of left ventricular contractility res ulted in a significant rise of the magnitude of CVIB and the decrease of left ventricular contractility resulted in a significant fall of the magnitude of CVIB.
文摘The possible existence of neutrino astronomical objects (NAO) arouses great interests in the transparent gravitational lenses. The basic equations of gravitational lenses have already been obtained. In this note we shall deduce the location and the number of the images of a star produced by a spherically
文摘Nuclear magnetic resonance (NMR) spectra are usually measured either by continuous wave (CW) method or by pulse Fouries transform (PFT) method.Total or part spectra measured by CW method are undistorted, but the sensitivity is lower.
文摘According to the No. 14 proclamation issued by Customs Service, as from April 1st 2007, the importation of galena and the lead ore concentrate will enjoy the favorable policy intended for associated gold deposits, i.e. the value-added tax for gold component in the imported galena and lead ore concentrate is exempted,
文摘On June 8th,Liaoning Chengda Co.,Ltd.(SH: 600739) announced todevelop oil shale resources in Xinjiang region.The company has signeda letter of intend with Xinjiang Baoming Mine Co.,Ltd.Xinjiang Baoming Mine has four licenses for oil shale explorationwith a total exploration area of 70.24 square kilometers.Under the initial agreement,Liaoning Chengda will purchase a 60%stake of Xinjiang Baoming,making it a joint venture.
文摘With the ever intense competition in sports,higher requirements are placed not only on athletes but also on professional sports equip-ments as well.Carbon fiber with
