Two-dimensional(2D)magnetic materials have been demonstrated to have excellent chemical,optical,electrical,and magnetic properties,particularly in the development of multifunctional electronic and spin electronic devi...Two-dimensional(2D)magnetic materials have been demonstrated to have excellent chemical,optical,electrical,and magnetic properties,particularly in the development of multifunctional electronic and spin electronic devices,showcasing tremendous potential.Therefore,corresponding synthesis techniques for 2D magnetic materials that offer high quality,high yield,low cost,time-saving,and simplicity are highly desired.This review provides a comprehensive overview of recent research advances in preparation of magnetic 2D materials,with a particular focus on the preparation methods employed.Moreover,the characteristics and applications of these magnetic materials are also discussed.Finally,the challenges and prospects of synthesis methods for magnetic 2D materials are briefly addressed.This review serves as a guiding reference for the controlled synthesis of 2D magnetic materials.展开更多
The deformation and failure mechanism of cylindrical shells and square plate with pre-formed holes under blast loading were investigated numerically by employing the Ansys 17.0 and Ls-Dyna 971.To calibrate the numeric...The deformation and failure mechanism of cylindrical shells and square plate with pre-formed holes under blast loading were investigated numerically by employing the Ansys 17.0 and Ls-Dyna 971.To calibrate the numerical model,the experiments of square plates with pre-formed circle holes were modeled and the numerical results have a good agreement with the experiment data.The calibrated numerical model was used to study the deformation and failure mechanism of cylindrical shells with pre-formed circle holes subjected to blast loading.The structure response and stress field changing process has been divided into four specific stages and the deformation mechanism has been discussed systematically.The local and global deformation curves,degree of damage,change of stress status and failure modes of cylindrical shell and square plate with pre-formed circular holes are obtained,compared and analyzed,it can be concluded as:(1)The transition of tensile stress fields is due to the geometrical characteristic of pre-formed holes and cylindrical shell with arch configuration;(2)The existence of preformed holes not only lead to the increasing of stress concentration around the holes,but also release the stress concentration during whole response process;(3)There are three and two kinds of failure modes for square plate and cylindrical shell with pre-formed holes,respectively.and the standoff distance has a key influence on the forming location of the crack initiating point and the locus of crack propagation;(4)The square plate with pre-formed holes has a better performance than cylindrical shell on blast-resistant capability at a smaller standoff distance,while the influence of pre-formed holes on the reduction of blast-resistant capability of square plate is bigger than that of cylindrical shell.展开更多
In recent years,two-dimensional(2D)materials have attracted extensive attention from researchers for their unique structures and electrical properties.2D materials have been widely applied in field effect transistors,...In recent years,two-dimensional(2D)materials have attracted extensive attention from researchers for their unique structures and electrical properties.2D materials have been widely applied in field effect transistors,sensors,and photodetectors.Integration is extremely important for practical applications in devices,which requires both minimal crosstalk and high performance.The fabrication of patterned arrays of 2D materials can realize high-density fabrication.In addition,the properties of 2D materials can be also adjusted by the patterned nanostructures.In this review,we summarize the emerging researches related to 2D materials and arrays.Firstly,the preparation strategies of different arrays have been introduced.Then,the applications of arrays have been investigated,such as physical unclonable functions,sensors,energy consumption,photoluminescence enhancement,quantum emitters and photodetectors.Finally,the prospects and existing challenges have been proposed.展开更多
The machining accuracy of computer numerical control machine tools has always been a focus of the manufacturing industry.Among all errors,thermal error affects the machining accuracy considerably.Because of the signif...The machining accuracy of computer numerical control machine tools has always been a focus of the manufacturing industry.Among all errors,thermal error affects the machining accuracy considerably.Because of the significant impact of Industry 4.0 on machine tools,existing thermal error modeling methods have encountered unprecedented challenges in terms of model complexity and capability of dealing with a large number of time series data.A thermal error modeling method is proposed based on bidirectional long short-term memory(BiLSTM)deep learning,which has good learning ability and a strong capability to handle a large group of dynamic data.A four-layer model framework that includes BiLSTM,a feedforward neural network,and the max pooling is constructed.An elaborately designed algorithm is proposed for better and faster model training.The window length of the input sequence is selected based on the phase space reconstruction of the time series.The model prediction accuracy and model robustness were verified experimentally by three validation tests in which thermal errors predicted by the proposed model were compensated for real workpiece cutting.The average depth variation of the workpiece was reduced from approximately 50μm to less than 2μm after compensation.The reduction in maximum depth variation was more than 85%.The proposed model was proved to be feasible and effective for improving machining accuracy significantly.展开更多
Background:A One Health approach has been increasingly mainstreamed by the international community, as it provides for holistic thinking in recognizing the close links and inter-dependence of the health of humans, ani...Background:A One Health approach has been increasingly mainstreamed by the international community, as it provides for holistic thinking in recognizing the close links and inter-dependence of the health of humans, animals and the environment. However, the dearth of real-world evidence has hampered application of a One Health approach in shaping policies and practice. This study proposes the development of a potential evaluation tool for One Health performance, in order to contribute to the scientific measurement of One Health approach and the identification of gaps where One Health capacity building is most urgently needed.Methods:We describe five steps towards a global One Health index (GOHI), including (i) framework formulation;(ii) indicator selection;(iii) database building;(iv) weight determination;and (v) GOHI scores calculation. A cell-like framework for GOHI is proposed, which comprises an external drivers index (EDI), an intrinsic drivers index (IDI) and a core drivers index (CDI). We construct the indicator scheme for GOHI based on this framework after multiple rounds of panel discussions with our expert advisory committee. A fuzzy analytical hierarchy process is adopted to determine the weights for each of the indicators.Results:The weighted indicator scheme of GOHI comprises three first-level indicators, 13 second-level indicators, and 57 third-level indicators. According to the pilot analysis based on the data from more than 200 countries/territories the GOHI scores overall are far from ideal (the highest score of 65.0 out of a maximum score of 100), and we found considerable variations among different countries/territories (31.8–65.0). The results from the pilot analysis are consistent with the results from a literature review, which suggests that a GOHI as a potential tool for the assessment of One Health performance might be feasible.Conclusions:GOHI—subject to rigorous validation—would represent the world’s first evaluation tool that constructs the conceptual framework from a holistic perspective of One Health. Future application of GOHI might promote a common understanding of a strong One Health approach and provide reference for promoting effective measures to strengthen One Health capacity building. With further adaptations under various scenarios, GOHI, along with its technical protocols and databases, will be updated regularly to address current technical limitations, and capture new knowledge.展开更多
The medicinal part of Aucklandia lappa(Asteraceae) is its dried root,which is one of the commonly used Chinese medicinal materials.Here we reviewed sesquiterpene lactones isolated from A.lappa over the past ten years ...The medicinal part of Aucklandia lappa(Asteraceae) is its dried root,which is one of the commonly used Chinese medicinal materials.Here we reviewed sesquiterpene lactones isolated from A.lappa over the past ten years in the following aspects of pharmacological activities,pharmacokinetics,toxicology,structure-activity relationship.Pharmacological activities consist of anti-cancer,anti-inflammatory activity,anti-immunity activity,anti-oxidant activity,antimicrobial activity,spasmolytic activity and so on.The extractive,showing similar pharmacokinetics parameters,may exert their various biological activities by the interaction of their α-methylene-γ-butyrolactone moiety with the thiol groups of biomacromolecules through Michael-addition.However,the poor aqueous solubility,non-selective binding as a Michael acceptor at undesired targets limited clinical translation of this class.In order to evaluate the potential effect of the extractive applied in clinical trial,the present review outlines information on pharmacological activities,pharmacokinetics,toxicology,and structure-activity relationship,as well as the future research directions of the extractive for further development and utilization of A.lappa.展开更多
The complete mitochondrial genome of Ampittia dioscorides （Lepidoptera： Hesperiidae） was determined. The sequenced genome is a circular molecule of 15313 bp, containing 13 protein-coding genes （PCGs）, 22 tRNA gen...The complete mitochondrial genome of Ampittia dioscorides （Lepidoptera： Hesperiidae） was determined. The sequenced genome is a circular molecule of 15313 bp, containing 13 protein-coding genes （PCGs）, 22 tRNA genes, two rRNA genes, and an A ＋ T-rich region. The gene arrangements and transcribing directions are identical to those in most of the reported lepidopteran mitogenomes. The base composition of the whole genome and genes or regions are also similar to those in other lepidopteran species. All the PCGs are initiated by typical ATN codons; the exception being CO1, which begins with a CGA codon. Eight genes （ND2, ATPase8, ATPase6, COIII, ND5, ND4L, ND6, and Cytb） end with a TAA stop codon, and two genes （ND1 and ND3） end with TAG. The remaining three genes （CO1 and COIl, which end with TA-, and ND4, which ends with T-） have incomplete stop codons. All tRNAs have the typical clover-leaf structure of mitochondrial tRNAs, with the exception of tRNAser（AGY）. On the basis of the concatenated nucleotide and amino acid sequences of the 13 PCGs and wingless gene of 22 butterfly species, maximum parsimony （MP） and Bayesian inference （BI） trees were constructed, respectively. Both MP and BI trees had the same topological structure： （（（（Nymphalidae ＋ Danaidae） ＋ Lycaenidae） ＋ Pieridae） ＋ Papilionidae） ＋ Hesperiidae）. The results provide support for Hesperiidae as a superfamily-level taxon.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.22175060 and 21975067)the Natural Science Foundation of Hunan Province of China(Grant Nos.2021JJ10014 and 2021JJ30092).
文摘Two-dimensional(2D)magnetic materials have been demonstrated to have excellent chemical,optical,electrical,and magnetic properties,particularly in the development of multifunctional electronic and spin electronic devices,showcasing tremendous potential.Therefore,corresponding synthesis techniques for 2D magnetic materials that offer high quality,high yield,low cost,time-saving,and simplicity are highly desired.This review provides a comprehensive overview of recent research advances in preparation of magnetic 2D materials,with a particular focus on the preparation methods employed.Moreover,the characteristics and applications of these magnetic materials are also discussed.Finally,the challenges and prospects of synthesis methods for magnetic 2D materials are briefly addressed.This review serves as a guiding reference for the controlled synthesis of 2D magnetic materials.
基金The reported research is financially supported by The National Natural Science Foundation of China under Grant No.11902310 and No.11802292.
文摘The deformation and failure mechanism of cylindrical shells and square plate with pre-formed holes under blast loading were investigated numerically by employing the Ansys 17.0 and Ls-Dyna 971.To calibrate the numerical model,the experiments of square plates with pre-formed circle holes were modeled and the numerical results have a good agreement with the experiment data.The calibrated numerical model was used to study the deformation and failure mechanism of cylindrical shells with pre-formed circle holes subjected to blast loading.The structure response and stress field changing process has been divided into four specific stages and the deformation mechanism has been discussed systematically.The local and global deformation curves,degree of damage,change of stress status and failure modes of cylindrical shell and square plate with pre-formed circular holes are obtained,compared and analyzed,it can be concluded as:(1)The transition of tensile stress fields is due to the geometrical characteristic of pre-formed holes and cylindrical shell with arch configuration;(2)The existence of preformed holes not only lead to the increasing of stress concentration around the holes,but also release the stress concentration during whole response process;(3)There are three and two kinds of failure modes for square plate and cylindrical shell with pre-formed holes,respectively.and the standoff distance has a key influence on the forming location of the crack initiating point and the locus of crack propagation;(4)The square plate with pre-formed holes has a better performance than cylindrical shell on blast-resistant capability at a smaller standoff distance,while the influence of pre-formed holes on the reduction of blast-resistant capability of square plate is bigger than that of cylindrical shell.
基金This work was financially supported by the National Natural Science Foundation of China(No.21975067)the Fundamental Research Funds for the Central Universities from Hunan University.
文摘In recent years,two-dimensional(2D)materials have attracted extensive attention from researchers for their unique structures and electrical properties.2D materials have been widely applied in field effect transistors,sensors,and photodetectors.Integration is extremely important for practical applications in devices,which requires both minimal crosstalk and high performance.The fabrication of patterned arrays of 2D materials can realize high-density fabrication.In addition,the properties of 2D materials can be also adjusted by the patterned nanostructures.In this review,we summarize the emerging researches related to 2D materials and arrays.Firstly,the preparation strategies of different arrays have been introduced.Then,the applications of arrays have been investigated,such as physical unclonable functions,sensors,energy consumption,photoluminescence enhancement,quantum emitters and photodetectors.Finally,the prospects and existing challenges have been proposed.
基金sponsored by the National Natural Science Foundation of Major Special Instruments(Grant No.51527806)the National Natural Science Foundation Projects of the People’s Republic of China(Grant No.51975372).
文摘The machining accuracy of computer numerical control machine tools has always been a focus of the manufacturing industry.Among all errors,thermal error affects the machining accuracy considerably.Because of the significant impact of Industry 4.0 on machine tools,existing thermal error modeling methods have encountered unprecedented challenges in terms of model complexity and capability of dealing with a large number of time series data.A thermal error modeling method is proposed based on bidirectional long short-term memory(BiLSTM)deep learning,which has good learning ability and a strong capability to handle a large group of dynamic data.A four-layer model framework that includes BiLSTM,a feedforward neural network,and the max pooling is constructed.An elaborately designed algorithm is proposed for better and faster model training.The window length of the input sequence is selected based on the phase space reconstruction of the time series.The model prediction accuracy and model robustness were verified experimentally by three validation tests in which thermal errors predicted by the proposed model were compensated for real workpiece cutting.The average depth variation of the workpiece was reduced from approximately 50μm to less than 2μm after compensation.The reduction in maximum depth variation was more than 85%.The proposed model was proved to be feasible and effective for improving machining accuracy significantly.
基金The project was supported by China Medical Board(no.20-365)Shanghai Jiao Tong University Integrated Innovation Fund(no.2020-01).
文摘Background:A One Health approach has been increasingly mainstreamed by the international community, as it provides for holistic thinking in recognizing the close links and inter-dependence of the health of humans, animals and the environment. However, the dearth of real-world evidence has hampered application of a One Health approach in shaping policies and practice. This study proposes the development of a potential evaluation tool for One Health performance, in order to contribute to the scientific measurement of One Health approach and the identification of gaps where One Health capacity building is most urgently needed.Methods:We describe five steps towards a global One Health index (GOHI), including (i) framework formulation;(ii) indicator selection;(iii) database building;(iv) weight determination;and (v) GOHI scores calculation. A cell-like framework for GOHI is proposed, which comprises an external drivers index (EDI), an intrinsic drivers index (IDI) and a core drivers index (CDI). We construct the indicator scheme for GOHI based on this framework after multiple rounds of panel discussions with our expert advisory committee. A fuzzy analytical hierarchy process is adopted to determine the weights for each of the indicators.Results:The weighted indicator scheme of GOHI comprises three first-level indicators, 13 second-level indicators, and 57 third-level indicators. According to the pilot analysis based on the data from more than 200 countries/territories the GOHI scores overall are far from ideal (the highest score of 65.0 out of a maximum score of 100), and we found considerable variations among different countries/territories (31.8–65.0). The results from the pilot analysis are consistent with the results from a literature review, which suggests that a GOHI as a potential tool for the assessment of One Health performance might be feasible.Conclusions:GOHI—subject to rigorous validation—would represent the world’s first evaluation tool that constructs the conceptual framework from a holistic perspective of One Health. Future application of GOHI might promote a common understanding of a strong One Health approach and provide reference for promoting effective measures to strengthen One Health capacity building. With further adaptations under various scenarios, GOHI, along with its technical protocols and databases, will be updated regularly to address current technical limitations, and capture new knowledge.
基金supported by Special Financial Grant from the China Postdoctoral Science Foundation (No.2015T81140)National Natural Science Foundation of China Youth Fund Project (No.81503467)。
文摘The medicinal part of Aucklandia lappa(Asteraceae) is its dried root,which is one of the commonly used Chinese medicinal materials.Here we reviewed sesquiterpene lactones isolated from A.lappa over the past ten years in the following aspects of pharmacological activities,pharmacokinetics,toxicology,structure-activity relationship.Pharmacological activities consist of anti-cancer,anti-inflammatory activity,anti-immunity activity,anti-oxidant activity,antimicrobial activity,spasmolytic activity and so on.The extractive,showing similar pharmacokinetics parameters,may exert their various biological activities by the interaction of their α-methylene-γ-butyrolactone moiety with the thiol groups of biomacromolecules through Michael-addition.However,the poor aqueous solubility,non-selective binding as a Michael acceptor at undesired targets limited clinical translation of this class.In order to evaluate the potential effect of the extractive applied in clinical trial,the present review outlines information on pharmacological activities,pharmacokinetics,toxicology,and structure-activity relationship,as well as the future research directions of the extractive for further development and utilization of A.lappa.
文摘The complete mitochondrial genome of Ampittia dioscorides （Lepidoptera： Hesperiidae） was determined. The sequenced genome is a circular molecule of 15313 bp, containing 13 protein-coding genes （PCGs）, 22 tRNA genes, two rRNA genes, and an A ＋ T-rich region. The gene arrangements and transcribing directions are identical to those in most of the reported lepidopteran mitogenomes. The base composition of the whole genome and genes or regions are also similar to those in other lepidopteran species. All the PCGs are initiated by typical ATN codons; the exception being CO1, which begins with a CGA codon. Eight genes （ND2, ATPase8, ATPase6, COIII, ND5, ND4L, ND6, and Cytb） end with a TAA stop codon, and two genes （ND1 and ND3） end with TAG. The remaining three genes （CO1 and COIl, which end with TA-, and ND4, which ends with T-） have incomplete stop codons. All tRNAs have the typical clover-leaf structure of mitochondrial tRNAs, with the exception of tRNAser（AGY）. On the basis of the concatenated nucleotide and amino acid sequences of the 13 PCGs and wingless gene of 22 butterfly species, maximum parsimony （MP） and Bayesian inference （BI） trees were constructed, respectively. Both MP and BI trees had the same topological structure： （（（（Nymphalidae ＋ Danaidae） ＋ Lycaenidae） ＋ Pieridae） ＋ Papilionidae） ＋ Hesperiidae）. The results provide support for Hesperiidae as a superfamily-level taxon.
