With the human space exploration activities,space life science is an emerging interdisciplinary and it covers a wide range of research.Based on our country's manned space station and recoverable satellite science ...With the human space exploration activities,space life science is an emerging interdisciplinary and it covers a wide range of research.Based on our country's manned space station and recoverable satellite science experimental platform,the development of space life science research is very important to acquire new knowledge or new innovation in technology,to give further services to the human space exploration activities,to improve the national economic and social development.Based on present situation,both theoretical and applied researches were continuously performed in2015.Here,we review and summarize the researches on space life sciences which were contributed by Chinese scientists.展开更多
Reliable and selective sensing of dopamine(DA)is essential for early diagnosis of mental diseases.Among the various potential methods,nanozyme-based sensing systems have demonstrated promising sensitivity and reliabil...Reliable and selective sensing of dopamine(DA)is essential for early diagnosis of mental diseases.Among the various potential methods,nanozyme-based sensing systems have demonstrated promising sensitivity and reliability.However,owing to the lack of substrate specificity,it is challenging to selectively detect DA using nanozymes.Herein,based on the reactivity of the DA oxidation intermediates,we report a cascade colorimetric sensing system for the selective detection of DA using only a single nanozyme.It was disclosed that the oxidation product of DA catalyzed by Co-N-doped carbon sheets(Co-N-C,a common oxidase-like nanozyme),dopamine quinone(DAQ),showed significant biocatalytic electron-donating activity in the reduction of O_(2)to generate O_(2)·-.Further using O_(2)·-to oxidize3,3,5,5-tetramethylbenzidine(TMB),a colorimetric sensing platform for DA was constructed with a linear detection range of 50 nmol/L to 50μmol/L and a low limit of detection of 4 nmol/L.Thanks to the reactivity of the oxidation product,without any biometric units(such as nucleic acids,enzymes,and antibodies/antigens),the reaction selectivity of DA against other interferences(e.g.,ascorbic acid,adrenaline,5-hydroxytryptamine,and glutathione)was enhanced up to 71-fold.Beyond complicated cascade systems requiring at least two nanozymes,sophisticated artificial recognition via multiple interactions was simplified by exploiting the oxidative properties of product intermediates;thus,only a single common oxidase-like nanozyme was needed.This work offers a new strategy to enhance the selectivity of nanozymes for bioanalytical applications.展开更多
Fourier integral operators play an important role in Fourier analysis and partial differential equations. In this paper, we deal with the boundedness of the bilinear and bi-parameter Fourier integral operators, which ...Fourier integral operators play an important role in Fourier analysis and partial differential equations. In this paper, we deal with the boundedness of the bilinear and bi-parameter Fourier integral operators, which are motivated by the study of one-parameter FIOs and bilinear and bi-parameter Fourier multipliers and pseudo-differential operators. We consider such FIOs when they have compact support in spatial variables. If they contain a real-valued phase φ（x, ξ, η） which is jointly homogeneous in the frequency variables ξ, η, and amplitudes of order zero supported away from the axes and the anti- diagonal, we can show that the boundedness holds in the local-L2 case. Some stronger boundedness results are also obtained under more restricted conditions on the phase functions. Thus our results extend the boundedness results for bilinear and one-parameter FIOs and bilinear and bi-parameter pseudo-differential operators to the case of bilinear and bi-parameter FIOs.展开更多
Emerging as cost-effective potential alternatives to natural enzymes,nanozymes have attracted increasing interest in broad fields.To exploit the in-depth potential of nanozymes,rational structural engineering and expl...Emerging as cost-effective potential alternatives to natural enzymes,nanozymes have attracted increasing interest in broad fields.To exploit the in-depth potential of nanozymes,rational structural engineering and explicit catalytic mechanisms at the molecular scale are required.Recently,impressive progress has been made in mimicking the characteristics of natural enzymes by constructing metal active sites,binding pockets,scaffolds,and delicate allosteric regulation.Ingenious in-depth studies have been conducted with advances in structural characterization and theoretical calculations,unveiling the“black box”of nanozymecatalytic mechanisms.This review introduces the state-of-art synthesis strategies by learning from the natural enzyme counterparts and summarizes the general overview of the nanozyme mechanism with a particular emphasis on the adsorbed intermediates and descriptors that predict the nanozyme activity.The emerging activity assessment methodology that illustrates the relationship between electrochemical oxygen reduction and enzymatic oxygen reduction is discussed with up-to-date advances.Future opportunities and challenges are presented in the end to spark more profound work and attract more researchers from various backgrounds to the flourishing field of nanozymes.展开更多
Background:Intelligent monitoring of human action in production is an important step to help standardize production processes and construct a digital twin shop-floor rapidly.Human action has a significant impact on th...Background:Intelligent monitoring of human action in production is an important step to help standardize production processes and construct a digital twin shop-floor rapidly.Human action has a significant impact on the production safety and efficiency of a shop-floor,however,because of the high individual initiative of humans,it is difficult to realize real-time action detection in a digital twin shop-floor.Methods:We proposed a real-time detection approach for shop-floor production action.This approach used the sequence data of continuous human skeleton joints sequences as the input.We then reconstructed the Joint Classification-Regression Recurrent Neural Networks(JCR-RNN)based on Temporal Convolution Network(TCN)and Graph Convolution Network(GCN).We called this approach the Temporal Action Detection Net(TAD-Net),which realized real-time shop-floor production action detection.Results:The results of the verification experiment showed that our approach has achieved a high temporal positioning score,recognition speed,and accuracy when applied to the existing Online Action Detection(OAD)dataset and the Nanjing University of Science and Technology 3 Dimensions(NJUST3D)dataset.TAD-Net can meet the actual needs of the digital twin shop-floor.Conclusions:Our method has higher recognition accuracy,temporal positioning accuracy,and faster running speed than other mainstream network models,it can better meet actual application requirements,and has important research value and practical significance for standardizing shop-floor production processes,reducing production security risks,and contributing to the understanding of real-time production action.展开更多
The digital twin shop-floor has received much attention from the manufacturing industry as it is an important way to upgrade the shop-floor digitally and intelligently.As a key part of the shop-floor,humans'high a...The digital twin shop-floor has received much attention from the manufacturing industry as it is an important way to upgrade the shop-floor digitally and intelligently.As a key part of the shop-floor,humans'high autonomy and uncertainty leads to the difficulty in digital twin modeling of human behavior.Therefore,the modeling system for cross-scale human behavior in digital twin shop-floors was developed,powered by the data fusion of macro-behavior and micro-behavior virtual models.Shop-floor human macro-behavior mainly refers to the role of the human and their real-time position.Shop-floor micro-behavior mainly refers to real-time human limb posture and production behavior at their workstation.In this study,we reviewed and summarized a set of theoretical systems for cross-scale human behavior modeling in digital twin shop-floors.Based on this theoretical system,we then reviewed modeling theory and technology from macro-behavior and micro-behavior aspects to analyze the research status of shop-floor human behavior modeling.Lastly,we discuss and offer opinion on the application of cross-scale human behavior modeling in digital twin shop-floors.Cross-scale human behavior modeling is the key for realizing closed-loop interactive drive of human behavior in digital twin shop-floors.展开更多
文摘With the human space exploration activities,space life science is an emerging interdisciplinary and it covers a wide range of research.Based on our country's manned space station and recoverable satellite science experimental platform,the development of space life science research is very important to acquire new knowledge or new innovation in technology,to give further services to the human space exploration activities,to improve the national economic and social development.Based on present situation,both theoretical and applied researches were continuously performed in2015.Here,we review and summarize the researches on space life sciences which were contributed by Chinese scientists.
基金supported by the National Natural Science Foundation of China(Nos.22174014 and 22074015)。
文摘Reliable and selective sensing of dopamine(DA)is essential for early diagnosis of mental diseases.Among the various potential methods,nanozyme-based sensing systems have demonstrated promising sensitivity and reliability.However,owing to the lack of substrate specificity,it is challenging to selectively detect DA using nanozymes.Herein,based on the reactivity of the DA oxidation intermediates,we report a cascade colorimetric sensing system for the selective detection of DA using only a single nanozyme.It was disclosed that the oxidation product of DA catalyzed by Co-N-doped carbon sheets(Co-N-C,a common oxidase-like nanozyme),dopamine quinone(DAQ),showed significant biocatalytic electron-donating activity in the reduction of O_(2)to generate O_(2)·-.Further using O_(2)·-to oxidize3,3,5,5-tetramethylbenzidine(TMB),a colorimetric sensing platform for DA was constructed with a linear detection range of 50 nmol/L to 50μmol/L and a low limit of detection of 4 nmol/L.Thanks to the reactivity of the oxidation product,without any biometric units(such as nucleic acids,enzymes,and antibodies/antigens),the reaction selectivity of DA against other interferences(e.g.,ascorbic acid,adrenaline,5-hydroxytryptamine,and glutathione)was enhanced up to 71-fold.Beyond complicated cascade systems requiring at least two nanozymes,sophisticated artificial recognition via multiple interactions was simplified by exploiting the oxidative properties of product intermediates;thus,only a single common oxidase-like nanozyme was needed.This work offers a new strategy to enhance the selectivity of nanozymes for bioanalytical applications.
基金supported by NNSF of China(Grant No.11371056)supported by NSF grant
文摘Fourier integral operators play an important role in Fourier analysis and partial differential equations. In this paper, we deal with the boundedness of the bilinear and bi-parameter Fourier integral operators, which are motivated by the study of one-parameter FIOs and bilinear and bi-parameter Fourier multipliers and pseudo-differential operators. We consider such FIOs when they have compact support in spatial variables. If they contain a real-valued phase φ（x, ξ, η） which is jointly homogeneous in the frequency variables ξ, η, and amplitudes of order zero supported away from the axes and the anti- diagonal, we can show that the boundedness holds in the local-L2 case. Some stronger boundedness results are also obtained under more restricted conditions on the phase functions. Thus our results extend the boundedness results for bilinear and one-parameter FIOs and bilinear and bi-parameter pseudo-differential operators to the case of bilinear and bi-parameter FIOs.
基金supported by the National Natural Science Foundation of China(22174014 and 22074015)Natural Science Foundation of Jiangsu Province(BK20220802)。
文摘Emerging as cost-effective potential alternatives to natural enzymes,nanozymes have attracted increasing interest in broad fields.To exploit the in-depth potential of nanozymes,rational structural engineering and explicit catalytic mechanisms at the molecular scale are required.Recently,impressive progress has been made in mimicking the characteristics of natural enzymes by constructing metal active sites,binding pockets,scaffolds,and delicate allosteric regulation.Ingenious in-depth studies have been conducted with advances in structural characterization and theoretical calculations,unveiling the“black box”of nanozymecatalytic mechanisms.This review introduces the state-of-art synthesis strategies by learning from the natural enzyme counterparts and summarizes the general overview of the nanozyme mechanism with a particular emphasis on the adsorbed intermediates and descriptors that predict the nanozyme activity.The emerging activity assessment methodology that illustrates the relationship between electrochemical oxygen reduction and enzymatic oxygen reduction is discussed with up-to-date advances.Future opportunities and challenges are presented in the end to spark more profound work and attract more researchers from various backgrounds to the flourishing field of nanozymes.
基金This work was supported by the National Key Research and Development Program,China(2020YFB1708400)the National Defense Fundamental Research Program,China(JCKY2020210B006,JCKY2017204B053)awarded to TL.
文摘Background:Intelligent monitoring of human action in production is an important step to help standardize production processes and construct a digital twin shop-floor rapidly.Human action has a significant impact on the production safety and efficiency of a shop-floor,however,because of the high individual initiative of humans,it is difficult to realize real-time action detection in a digital twin shop-floor.Methods:We proposed a real-time detection approach for shop-floor production action.This approach used the sequence data of continuous human skeleton joints sequences as the input.We then reconstructed the Joint Classification-Regression Recurrent Neural Networks(JCR-RNN)based on Temporal Convolution Network(TCN)and Graph Convolution Network(GCN).We called this approach the Temporal Action Detection Net(TAD-Net),which realized real-time shop-floor production action detection.Results:The results of the verification experiment showed that our approach has achieved a high temporal positioning score,recognition speed,and accuracy when applied to the existing Online Action Detection(OAD)dataset and the Nanjing University of Science and Technology 3 Dimensions(NJUST3D)dataset.TAD-Net can meet the actual needs of the digital twin shop-floor.Conclusions:Our method has higher recognition accuracy,temporal positioning accuracy,and faster running speed than other mainstream network models,it can better meet actual application requirements,and has important research value and practical significance for standardizing shop-floor production processes,reducing production security risks,and contributing to the understanding of real-time production action.
基金This work was supported by the National Key Research and Development Program,China[2020YFB1708400]the National Defense Fundamental Research Program,China[JCKY2020210B006,JCKY2017204B053].
文摘The digital twin shop-floor has received much attention from the manufacturing industry as it is an important way to upgrade the shop-floor digitally and intelligently.As a key part of the shop-floor,humans'high autonomy and uncertainty leads to the difficulty in digital twin modeling of human behavior.Therefore,the modeling system for cross-scale human behavior in digital twin shop-floors was developed,powered by the data fusion of macro-behavior and micro-behavior virtual models.Shop-floor human macro-behavior mainly refers to the role of the human and their real-time position.Shop-floor micro-behavior mainly refers to real-time human limb posture and production behavior at their workstation.In this study,we reviewed and summarized a set of theoretical systems for cross-scale human behavior modeling in digital twin shop-floors.Based on this theoretical system,we then reviewed modeling theory and technology from macro-behavior and micro-behavior aspects to analyze the research status of shop-floor human behavior modeling.Lastly,we discuss and offer opinion on the application of cross-scale human behavior modeling in digital twin shop-floors.Cross-scale human behavior modeling is the key for realizing closed-loop interactive drive of human behavior in digital twin shop-floors.
