The visible light-driven C2 or C3 amination of indoles without any additives was initiated via electron donor-acceptor (EDA) complex formed by indole and N-aminopyridinium salt.This method was compatible with a wide r...The visible light-driven C2 or C3 amination of indoles without any additives was initiated via electron donor-acceptor (EDA) complex formed by indole and N-aminopyridinium salt.This method was compatible with a wide range of substrates and could proceed smoothly without the addition of any photocatalysts,transition-metal catalysts,or bases.A variety of studies were carried out to examine the presence of EDA complex.展开更多
Based on the diversity of the agricultural system, this research calculates the planting structures of rice, maize and soybean considering the optimal economic-social-ecological aspects. Then, based on the uncertainty...Based on the diversity of the agricultural system, this research calculates the planting structures of rice, maize and soybean considering the optimal economic-social-ecological aspects. Then, based on the uncertainty and randomness of the water resources system,the interval two-stage stochastic programming method,which introduces the uncertainty of the interval number, is used to calculate the groundwater exploitation and the use efficiency of surface water. The method considers the minimum cost of water as the objective of the uncertainty model for surface water and groundwater joint scheduling optimization for different planting structures. Finally, by calculating harmonious entropy, the optimal exploitation utilization interval of surface water and groundwater is determined for optimal cultivation in the Sanjiang Plain.The optimal matching of the planting structure under the economic system is suitable when the mining ratio of the surface is in 44.13%–45.45% and the exploitation utilization of groundwater is in 54.82%–66.86%, the optimal planting structure under the social system is suitable when surface water mining ratio is in 47.84%–48.04% and the groundwater exploitation threshold is in 67.07%–72.00%. This article optimizes the economicsocial-ecological-water system, which is important for the development of a water- and food-conserving society and providing a more accurate management environment.展开更多
A light-promoted metal-free protocol for the amination of imidazo[1,2-a]pyridines with N-aminopyridinium salt by the assistance of surfactants in water was reported,charactering mild and environmentally benign conditi...A light-promoted metal-free protocol for the amination of imidazo[1,2-a]pyridines with N-aminopyridinium salt by the assistance of surfactants in water was reported,charactering mild and environmentally benign conditions,as well as great functional group tolerance.Micelles with negatively charged polar surface and hydrophobic core formed from sodium dodecyl sulfate serve as an ideal medium for visible-light mediated radical reaction of cationic pyridine salt and imidazo[1,2-a]pyridine in aqueous phase.The electrostatic interaction between positively charged N-aminopyridinium and negatively charged surface of micelles is of great significance in this method.展开更多
Pore structure reflected from capillary pressure curves plays an important role in low-permeability formation evaluation. It is a common way to construct capillary pressure curves by Nuclear Magnetic Resonance（NMR） ...Pore structure reflected from capillary pressure curves plays an important role in low-permeability formation evaluation. It is a common way to construct capillary pressure curves by Nuclear Magnetic Resonance（NMR） log. However, the method＇s efficiency will be severely affected if there is no NMR log data or it cannot reflect pore structure well. Therefore, on the basis of J function and diagenetic facies classification, a new empirical model for constructing capillary pressure curves from conventional logs is proposed here as a solution to the problem. This model includes porosity and the relative value of natural gamma rays as independent variables and the saturation of mercury injection as a dependent variable. According to the 51 core experimental data sets of three diagenetic facies from the bottom of the Upper Triassic in the western Ordos Basin, China, the model＇s parameters in each diagenetic facies are calibrated. Both self-checking and extrapolation tests show a positive effect, which demonstrates the high reliability of the proposed capillary pressure curve construction model. Based on the constructed capillary pressure curves, NMR T_2 spectra under fully brine-saturated conditions are mapped by a piecewise power function. A field study is then presented. Agreement can be seen between the mapped NMR T_2 spectra and the MRIL-Plog data in the location of the major peak, right boundary, distribution characteristics and T_2 logarithmic mean value. In addition, the capillary pressure curve construction model proposed in this paper is not affected by special log data or formation condition. It is of great importance in evaluating pore structure, predicting oil production and identifying oil layers through NMR log data in low-permeability sandstones.展开更多
The development of autonomous driving has brought with it requirements for intelligence,safety,and stability.One example of this is the need to construct effective forms of interactive cognition between pedestrians an...The development of autonomous driving has brought with it requirements for intelligence,safety,and stability.One example of this is the need to construct effective forms of interactive cognition between pedestrians and vehicles in dynamic,complex,and uncertain environments.Pedestrian action detection is a form of interactive cognition that is fundamental to the success of autonomous driving technologies.Specifically,vehicles need to detect pedestrians,recognize their limb movements,and understand the meaning of their actions before making appropriate decisions in response.In this survey,we present a detailed description of the architecture for pedestrian action recognition in autonomous driving,and compare the existing mainstream pedestrian action recognition techniques.We also introduce several commonly used datasets used in pedestrian motion recognition.Finally,we present several suggestions for future research directions.展开更多
Human action recognition and posture prediction aim to recognize and predict respectively the action and postures of persons in videos.They are both active research topics in computer vision community,which have attra...Human action recognition and posture prediction aim to recognize and predict respectively the action and postures of persons in videos.They are both active research topics in computer vision community,which have attracted considerable attention from academia and industry.They are also the precondition for intelligent interaction and human-computer cooperation,and they help the machine perceive the external environment.In the past decade,tremendous progress has been made in the field,especially after the emergence of deep learning technologies.Hence,it is necessary to make a comprehensive review of recent developments.In this paper,firstly,we attempt to present the background,and then discuss research progresses.Secondly,we introduce datasets,various typical feature representation methods,and explore advanced human action recognition and posture prediction algorithms.Finally,facing the challenges in the field,this paper puts forward the research focus,and introduces the importance of action recognition and posture prediction by taking interactive cognition in self-driving vehicle as an example.展开更多
基金financial support from the National Natural Science Foundation of China(Grant Nos.21901216 and 82074003,82174083)the Funds of Sichuan Science and Technology Program(23NSFSC0862,2021YFSY0041,2021YFH0064 and 2021ZHFP0032)+3 种基金the Opening subject under KF-202204 in the State Key Laboratory of Pharmaceutical Biotechnology,Nanjing University,China,the Fund of Science and Technology Agency of Chengdu(2019-YF09-00049-SN)the research project of the Administration of Traditional Chinese Medicine of Sichuan(2021MS110)the Open Project Program of Irradiation Preservation Technology Key Laboratory of Sichuan Province,Sichuan Institute of Atomic Energy(No.FZBC2020002)the Fundamental Research Funds for the Central Universities(2682020ZT85).
文摘The visible light-driven C2 or C3 amination of indoles without any additives was initiated via electron donor-acceptor (EDA) complex formed by indole and N-aminopyridinium salt.This method was compatible with a wide range of substrates and could proceed smoothly without the addition of any photocatalysts,transition-metal catalysts,or bases.A variety of studies were carried out to examine the presence of EDA complex.
基金supported by funds from National Natural Science Foundation of China (51179032, 51479032, 51579044)Yangtze River Scholars in Universities of Heilongjiang Province and Water Conservancy Science and Technology Project of Heilongjiang Province (201318, 201503)The Outstanding Youth Fund of Heilongjiang Province (JC201402)
文摘Based on the diversity of the agricultural system, this research calculates the planting structures of rice, maize and soybean considering the optimal economic-social-ecological aspects. Then, based on the uncertainty and randomness of the water resources system,the interval two-stage stochastic programming method,which introduces the uncertainty of the interval number, is used to calculate the groundwater exploitation and the use efficiency of surface water. The method considers the minimum cost of water as the objective of the uncertainty model for surface water and groundwater joint scheduling optimization for different planting structures. Finally, by calculating harmonious entropy, the optimal exploitation utilization interval of surface water and groundwater is determined for optimal cultivation in the Sanjiang Plain.The optimal matching of the planting structure under the economic system is suitable when the mining ratio of the surface is in 44.13%–45.45% and the exploitation utilization of groundwater is in 54.82%–66.86%, the optimal planting structure under the social system is suitable when surface water mining ratio is in 47.84%–48.04% and the groundwater exploitation threshold is in 67.07%–72.00%. This article optimizes the economicsocial-ecological-water system, which is important for the development of a water- and food-conserving society and providing a more accurate management environment.
基金We thank the National Natural Science Foundation of China(Grant Nos.21901216 and 21871031)the Fund of Science and Technology Agency of Chengdu(2019-YF09-00049-SN)+1 种基金the Open Project Program of Irradiation Preservation Technology Key Laboratory of Sichuan Province,Sichuan Institute of Atomic Energy(No.FZBC2020002)the Sichuan Science and Technology Program(2020YFH0061,2020YJ0222,2021JDRC0018,2021YFS0092,2021YFSY0041,2021YFH0064).
文摘A light-promoted metal-free protocol for the amination of imidazo[1,2-a]pyridines with N-aminopyridinium salt by the assistance of surfactants in water was reported,charactering mild and environmentally benign conditions,as well as great functional group tolerance.Micelles with negatively charged polar surface and hydrophobic core formed from sodium dodecyl sulfate serve as an ideal medium for visible-light mediated radical reaction of cationic pyridine salt and imidazo[1,2-a]pyridine in aqueous phase.The electrostatic interaction between positively charged N-aminopyridinium and negatively charged surface of micelles is of great significance in this method.
基金supported by the Scientific Research Starting Foundation of China University of Petroleum-Beijing at Karamay(No.RCYJ2016B-01-008)the Major National Oil&Gas Specific Project of China(No.2016ZX05050008)
文摘Pore structure reflected from capillary pressure curves plays an important role in low-permeability formation evaluation. It is a common way to construct capillary pressure curves by Nuclear Magnetic Resonance（NMR） log. However, the method＇s efficiency will be severely affected if there is no NMR log data or it cannot reflect pore structure well. Therefore, on the basis of J function and diagenetic facies classification, a new empirical model for constructing capillary pressure curves from conventional logs is proposed here as a solution to the problem. This model includes porosity and the relative value of natural gamma rays as independent variables and the saturation of mercury injection as a dependent variable. According to the 51 core experimental data sets of three diagenetic facies from the bottom of the Upper Triassic in the western Ordos Basin, China, the model＇s parameters in each diagenetic facies are calibrated. Both self-checking and extrapolation tests show a positive effect, which demonstrates the high reliability of the proposed capillary pressure curve construction model. Based on the constructed capillary pressure curves, NMR T_2 spectra under fully brine-saturated conditions are mapped by a piecewise power function. A field study is then presented. Agreement can be seen between the mapped NMR T_2 spectra and the MRIL-Plog data in the location of the major peak, right boundary, distribution characteristics and T_2 logarithmic mean value. In addition, the capillary pressure curve construction model proposed in this paper is not affected by special log data or formation condition. It is of great importance in evaluating pore structure, predicting oil production and identifying oil layers through NMR log data in low-permeability sandstones.
基金partially funded by the National Natural Science Foundation of China(Nos.61871038,61803034,and 61672178)Beijing Natural Science Foundation(No.4182022)Beijing Union University Graduate Funding Project.
文摘The development of autonomous driving has brought with it requirements for intelligence,safety,and stability.One example of this is the need to construct effective forms of interactive cognition between pedestrians and vehicles in dynamic,complex,and uncertain environments.Pedestrian action detection is a form of interactive cognition that is fundamental to the success of autonomous driving technologies.Specifically,vehicles need to detect pedestrians,recognize their limb movements,and understand the meaning of their actions before making appropriate decisions in response.In this survey,we present a detailed description of the architecture for pedestrian action recognition in autonomous driving,and compare the existing mainstream pedestrian action recognition techniques.We also introduce several commonly used datasets used in pedestrian motion recognition.Finally,we present several suggestions for future research directions.
基金supported by the National Natural Science Foundation of China(Nos.61871038 and 61931012)the Premium Funding Project for Academic Human Resources Development of Beijing Union University(No.BPHR2020AZ02)the Generic Pre-research Program of the Equipment Development Department in Military Commission(No.41412040302).
文摘Human action recognition and posture prediction aim to recognize and predict respectively the action and postures of persons in videos.They are both active research topics in computer vision community,which have attracted considerable attention from academia and industry.They are also the precondition for intelligent interaction and human-computer cooperation,and they help the machine perceive the external environment.In the past decade,tremendous progress has been made in the field,especially after the emergence of deep learning technologies.Hence,it is necessary to make a comprehensive review of recent developments.In this paper,firstly,we attempt to present the background,and then discuss research progresses.Secondly,we introduce datasets,various typical feature representation methods,and explore advanced human action recognition and posture prediction algorithms.Finally,facing the challenges in the field,this paper puts forward the research focus,and introduces the importance of action recognition and posture prediction by taking interactive cognition in self-driving vehicle as an example.
