The global textile supply chain is rapidly reshaping.China's textile industry faces unprecedented challenges and op-portunities in its high-end transformation.Breaking through hinges on independent innovation in c...The global textile supply chain is rapidly reshaping.China's textile industry faces unprecedented challenges and op-portunities in its high-end transformation.Breaking through hinges on independent innovation in core technologies and do-mestic substitution for textile machinery.News that Wanzhou Group,a leading textile company in Lanxi,Zhejiang,is replacing imported air jet looms with domestic ones has drawn significant industry attention.Driving this pivotal shift is Qingdao Haijia Machinery Co.,Ltd.(hereinafter referred to Haijia),a previously little-known domestic player in the air jet loom sector.展开更多
Second language(L2)motivation has been a topic which receives intensive attention.However,the peer effect on L2 motivation is insufficiently researched,although it is considered a crucial factor which may significantl...Second language(L2)motivation has been a topic which receives intensive attention.However,the peer effect on L2 motivation is insufficiently researched,although it is considered a crucial factor which may significantly mediate learners’L2 motivation.Hence,the current study adopted Dörnyei’s L2 Motivational Self System(L2MSS)as a theoretical framework and investigated in which specific aspects peers might affect the learners’L2 motivation and whether such effect was long-lasting.The research was designed as a small-scale qualitative study which was located in a language-focused experimental class project in China.Ten participants were recruited and individual interviews were conducted.The results demonstrated that,first,peers could remarkably influence the L2 motivation possessed by the students in the experimental class since they tended to create a clearer ideal L2 self and a more powerful ought-to L2 self.Second,although they had both positive and negative views towards the curriculum,a motivated peer climate could alleviate the pressure caused by the curriculum and reinforce positive attitudes.Third,such peer effect was not long-lasting.Based on the research results,pedagogical implications were proposed in terms of establishing a positive peer group and adjusting the emphasis of the curriculum.展开更多
Everyone is busy.But it's easy to be too busy.Then you may feel anxious or stressed.You need to take care of yourself.How can you do that?First,make time to text or call your family and friends.They care about you...Everyone is busy.But it's easy to be too busy.Then you may feel anxious or stressed.You need to take care of yourself.How can you do that?First,make time to text or call your family and friends.They care about you and can support you.Get regular exercise.展开更多
Are you tred of regular selfies?Try a self-photo studio!The lights and camera are ready for you.At the studio,you can fix your hair.There are clothes and props.You can use those and take fun photos.Bring your friends ...Are you tred of regular selfies?Try a self-photo studio!The lights and camera are ready for you.At the studio,you can fix your hair.There are clothes and props.You can use those and take fun photos.Bring your friends with you.Then you can take photos together.Pose in silly ways and have fun!You can take the photos home and remember your good time.展开更多
Yongtao Yu,Yuelin Yu et al.Solvent-Resistant Wearable Triboelectric Nanogenerator for Energy-Harvesting and Self-Powered Sensors.Energy Environ.Mater.2024,7,e12700.On page 4 of this article,the first paragraph of 2.4,...Yongtao Yu,Yuelin Yu et al.Solvent-Resistant Wearable Triboelectric Nanogenerator for Energy-Harvesting and Self-Powered Sensors.Energy Environ.Mater.2024,7,e12700.On page 4 of this article,the first paragraph of 2.4,line 14(PDF version,same below),there is a spelling mistake of“sui,”.It should be changed to“suitable”.The denominator“dt”in the Equation(3)should be changed to“dt”.展开更多
Water quality is a critical global issue,especially in urban and semi-urban regions where natural and anthropogenic factors significantly influence surface water systems.This study evaluates the hydrochemical characte...Water quality is a critical global issue,especially in urban and semi-urban regions where natural and anthropogenic factors significantly influence surface water systems.This study evaluates the hydrochemical characteristics of surface water in the North of Tehran Rivers(NTRs),an essential water resource in a rapidly urbanizing region,using advanced clustering techniques,including Hierarchical Clustering Analysis(HCA),Fuzzy CMeans(FCM),Genetic Algorithm Fuzzy C-Means(GAFCM),and Self-Organizing Map(SOM).The research aims to address the scientific challenge of understanding spatial and temporal variability in water quality,focusing on physicochemical parameters,hydrochemical facies,and contamination sources.Water samples from six rivers collected over four seasons in 2020 were analyzed and classified into distinct clusters based on their chemical composition,revealing significant seasonal and spatial differences.Results showed that FCM and GAFCM consistently categorized the NTRs into two clusters during winter and spring and three in summer and autumn.These findings were supported by HCA and SOM,which identified clusters corresponding to specific river segments and contamination levels.The primary hydrochemical processes identified were mineral dissolution and weathering,with calcite,dolomite,and aragonite significantly influencing water chemistry.Additionally,human activities,such as wastewater discharge,were shown to contribute to elevated sulfate,nitrate,and phosphate concentrations,further corroborated by microbial analyses.By integrating HCA,FCM,and GAFCM with an artificial neural network(ANN)-based clustering method(SOM),this study provides a robust framework for evaluating surface water quality.The findings,supported by Gibbs diagrams,Hounslow ion ratio,and saturation indices,highlight the dominance of rock weathering and human impacts in shaping the hydrochemical dynamics of the NTRs.These insights contribute to the scientific understanding of water quality dynamics and offer practical guidance for sustainable water resource management and environmental protection in developing urban areas.展开更多
In energy constrained application scenarios, self‐powered systems (SPSs) are gradually emerging as a core technological pathway for enabling distributed intelligent sensing. High‐entropy energy, such as micro‐wind,...In energy constrained application scenarios, self‐powered systems (SPSs) are gradually emerging as a core technological pathway for enabling distributed intelligent sensing. High‐entropy energy, such as micro‐wind, vibrations, water motion, and human activity, is widely available but difficult to harness due to its low density, randomness, and spatiotemporal fragmentation. Triboelectric nanogenerators (TENGs), with high efficiency to low‐frequency and irregular mechanical stimuli, offer a promising solution for efficient energy harvesting, driving the advancement of SPSs with high‐entropy distribution. This review outlines the basic concepts and recent developments of TENG‐driven SPSs, focusing on strategies for energy harvesting, power management, and system integration. It highlights structural optimization and performance enhancement under typical highentropy scenarios and analyzes key challenges in energy conversion, power regulation, and load management. Finally, the potential applications of TENG‐driven SPSs are discussed in emerging smart fields such as infrastructure monitoring, lowaltitude economy, mobile intelligent devices, and ocean sensing networks.展开更多
Flexible and wearable electronics are attracting surging attention due to their potential applications in human health monitoring and precision therapies.Safety hazards including strong magnetic field and electric lea...Flexible and wearable electronics are attracting surging attention due to their potential applications in human health monitoring and precision therapies.Safety hazards including strong magnetic field and electric leakage are big risk factors for human health.It remains challenging to develop self‐powered and wearable safety hazard sensors that could not only be able to monitor human motions but also have functions for detecting potential hazards.In this work,we fabricated a self‐powered,shapeable,and wearable magnetic triboelectric nanogenerator(MTENG)based on ferrofluid,Ecoflex,and carbonized silk fabric that possessed effective hazard prevention and biomechanical motion sensing ability.A peak open‐circuit voltage of 0.7 V and short‐circuit current of 10μA m^(−2)can be achieved when magnetic field is changed between 3.5 and 37.1 mT.As a component of triboelectric layer of the MTENG,ferrofluid can substantially extend the range of its sensing capabilities to many hazardous cues such as dangerous magnetic field.Furtherly,the developed multifunctional and self‐powered sensor can be used to monitor human activities such as drinking water and bending finger.This effort opens up a new design opportunity for hazard avoidance wearable electronics and self‐powered sensors.展开更多
On April 2,U.S.President Trump slapped“reciprocal tariffs”on over 100 global trading partners,hitting nine ASEAN member states hard.Alarmingly,even the UN-designated Least Developed Countries(LDCs)were not spared.Th...On April 2,U.S.President Trump slapped“reciprocal tariffs”on over 100 global trading partners,hitting nine ASEAN member states hard.Alarmingly,even the UN-designated Least Developed Countries(LDCs)were not spared.These included Cambodia,where nearly 20 percent of the population lives below the poverty line,facing a 49 percent tariff;Laos,with a poverty rate near 20 percent,facing 48 percent;and Myanmar,which recently suffered a devastating earthquake,facing 44 percent.展开更多
Convolutional neural network(CNN)with the encoder-decoder structure is popular in medical image segmentation due to its excellent local feature extraction ability but it faces limitations in capturing the global featu...Convolutional neural network(CNN)with the encoder-decoder structure is popular in medical image segmentation due to its excellent local feature extraction ability but it faces limitations in capturing the global feature.The transformer can extract the global information well but adapting it to small medical datasets is challenging and its computational complexity can be heavy.In this work,a serial and parallel network is proposed for the accurate 3D medical image segmentation by combining CNN and transformer and promoting feature interactions across various semantic levels.The core components of the proposed method include the cross window self-attention based transformer(CWST)and multi-scale local enhanced(MLE)modules.The CWST module enhances the global context understanding by partitioning 3D images into non-overlapping windows and calculating sparse global attention between windows.The MLE module selectively fuses features by computing the voxel attention between different branch features,and uses convolution to strengthen the dense local information.The experiments on the prostate,atrium,and pancreas MR/CT image datasets consistently demonstrate the advantage of the proposed method over six popular segmentation models in both qualitative evaluation and quantitative indexes such as dice similarity coefficient,Intersection over Union,95%Hausdorff distance and average symmetric surface distance.展开更多
The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based t...The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.展开更多
We present a minimal theoretical model for self-sustained oscillations of a thin elastic sheet on a hot plate,induced by thermomechanical coupling.As the plate temperature increases,the sheet’s static deflection beco...We present a minimal theoretical model for self-sustained oscillations of a thin elastic sheet on a hot plate,induced by thermomechanical coupling.As the plate temperature increases,the sheet’s static deflection becomes unstable via a Hopf bifurcation at a critical temperature TC,giving rise to spontaneous periodic motion.Linear stability analysis yields analytical expressions for the critical oscillation temperature TC and the oscillation period at onset.Numerical simulations of the nonlinear equations confirm the bifurcation and reveal how key parameters(stiffness,thermal softening,thermal coupling,etc.)govern the oscillation amplitude and waveform.Finally,we demonstrate that the self-oscillating sheet can perform mechanical work as a heat engine,and we compare its performance to the Carnot efficiency limit.This work provides design principles for thermally driven selfoscillators with potential applications in soft robotics,adaptive structures,and thermal energy harvesting.展开更多
Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is s...Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is still needed.Here,the storage mechanism of Li^(+)in the tunnel structure of MnO_(2) as well as the dissolution and migration of Mn-ions were investigated based on multi-scale approaches.The Li/Mn ratio(at%)is determined at about 0.82 when the discharge voltage decreases to 2 V.The limited Li-ions transport rate in the bulk MnO_(2) restrains the reduction reaction,resulting in a low practical specific capacity.Moreover,utilizing spherical aberration-corrected transmission electron microscopy(TEM)coupled with electron energy loss spectroscopy(EELS),the presence of a mixed valence state layer of Mn^(2+)/Mn^(3+)/Mn^(4+)on the surface of the original 20 nm MnO_(2) particles was identified,which could contribute to the initial dissolution of Mn-ions.The battery separator exhibited channels for Mn-ions migration and diffusion and aggregated Mn particles.We put forward the discharge and degradation route in the ways of Mn-ions trajectories,and our findings provide a deep understanding of the high self-discharge rates and the capacity decay of Li-Mn primary batteries.展开更多
Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous sta...Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous state monitoring. In contrast to the existing self-triggered control method, novel self-triggered mechanism(STM) is proposed by incorporating a waiting time for stabilizing impulses. This allows for direct prediction of the next impulsive instant.展开更多
There is limited amount of research on surface plasmon resonance(SPR)sensors with self-referencing capabilities which are based on dielectric gratings.In the short-wavelength range,a metal grating sensor is capable of...There is limited amount of research on surface plasmon resonance(SPR)sensors with self-referencing capabilities which are based on dielectric gratings.In the short-wavelength range,a metal grating sensor is capable of simultaneously measuring liquid refractive index under proposed temperature.A fabricated gold grating is placed on one side of a thin gold film for refractive index measurement,while the other with polydimethylsiloxane(PDMS)is deposited on the other side for temperature measurement.We use finite element analysis to research its sensing characteristics.Due to the high refractive index sensitivity of SPR sensors and thermo-optic coefficient of PDMS,we discovered the maximum spectral sensitivity of the sensor is 564 nm/RIU and-50 pm/℃when the liquid refractive index ranges from 1.30 to 1.40 with temperature ranging from 0℃ to 100℃.Numerical results indicate that there may not be mutual interference between two channels for measuring refractive index and temperature,which reduces the complexity of sensor measurements.展开更多
To the editor:Non-suicidal self-injury(NSSI)is an array of directly prepense or repetitive self-harm behaviours without suicidal intent.Individuals engage in self-injurious behaviours to reduce negative mental and cog...To the editor:Non-suicidal self-injury(NSSI)is an array of directly prepense or repetitive self-harm behaviours without suicidal intent.Individuals engage in self-injurious behaviours to reduce negative mental and cognitive states or evoke positive emotions.展开更多
Background Non-suicidal self-injury(NSSI)is a significant health concern among adolescents and young adults,often resulting from adverse childhood experiences(ACEs).Dissociation,post-traumatic symptoms and attachment ...Background Non-suicidal self-injury(NSSI)is a significant health concern among adolescents and young adults,often resulting from adverse childhood experiences(ACEs).Dissociation,post-traumatic symptoms and attachment style may have a role in shaping such associations.Aims This study aims to provide a unified model of the impact of ACEs on NSSI,exploring complex post-traumatic stress disorder(cPTSD)symptoms and dissociation as potential mediators and the role of the predominant attachment style in affecting such associations.Methods 1010 young individuals attending the last year of high school participated in this cross-sectional study.ACEs,cPTSD,dissociation and NSSI were evaluated using self-report questionnaires.We fitted a path model of NSSI,with ACEs as exogenous variables and cPTSD and dissociation as sequential mediators.Secure,fearful and preoccupied attachment styles were modelled as grouping variables.Results Our findings showed that dissociation mediated the impact of ACEs on NSSI in subjects with a fearful attachment style,as opposed to those with a preoccupied attachment for whom cPTSD symptoms mediated the ACEs-NSSI association.Conclusions Attachment styles moderate the relationship between ACEs and NSSI,with either dissociation or post-traumatic symptomatology mediating the impact of ACEs on NSSI,depending on the predominant attachment style.Our results highlight the importance of attachment as a pathway modifier in the relationships between different psychopathology dimensions,providing a useful framework to better conceptualise the ACEs-NSSI association.展开更多
文摘The global textile supply chain is rapidly reshaping.China's textile industry faces unprecedented challenges and op-portunities in its high-end transformation.Breaking through hinges on independent innovation in core technologies and do-mestic substitution for textile machinery.News that Wanzhou Group,a leading textile company in Lanxi,Zhejiang,is replacing imported air jet looms with domestic ones has drawn significant industry attention.Driving this pivotal shift is Qingdao Haijia Machinery Co.,Ltd.(hereinafter referred to Haijia),a previously little-known domestic player in the air jet loom sector.
文摘Second language(L2)motivation has been a topic which receives intensive attention.However,the peer effect on L2 motivation is insufficiently researched,although it is considered a crucial factor which may significantly mediate learners’L2 motivation.Hence,the current study adopted Dörnyei’s L2 Motivational Self System(L2MSS)as a theoretical framework and investigated in which specific aspects peers might affect the learners’L2 motivation and whether such effect was long-lasting.The research was designed as a small-scale qualitative study which was located in a language-focused experimental class project in China.Ten participants were recruited and individual interviews were conducted.The results demonstrated that,first,peers could remarkably influence the L2 motivation possessed by the students in the experimental class since they tended to create a clearer ideal L2 self and a more powerful ought-to L2 self.Second,although they had both positive and negative views towards the curriculum,a motivated peer climate could alleviate the pressure caused by the curriculum and reinforce positive attitudes.Third,such peer effect was not long-lasting.Based on the research results,pedagogical implications were proposed in terms of establishing a positive peer group and adjusting the emphasis of the curriculum.
文摘Everyone is busy.But it's easy to be too busy.Then you may feel anxious or stressed.You need to take care of yourself.How can you do that?First,make time to text or call your family and friends.They care about you and can support you.Get regular exercise.
文摘Are you tred of regular selfies?Try a self-photo studio!The lights and camera are ready for you.At the studio,you can fix your hair.There are clothes and props.You can use those and take fun photos.Bring your friends with you.Then you can take photos together.Pose in silly ways and have fun!You can take the photos home and remember your good time.
文摘Yongtao Yu,Yuelin Yu et al.Solvent-Resistant Wearable Triboelectric Nanogenerator for Energy-Harvesting and Self-Powered Sensors.Energy Environ.Mater.2024,7,e12700.On page 4 of this article,the first paragraph of 2.4,line 14(PDF version,same below),there is a spelling mistake of“sui,”.It should be changed to“suitable”.The denominator“dt”in the Equation(3)should be changed to“dt”.
文摘Water quality is a critical global issue,especially in urban and semi-urban regions where natural and anthropogenic factors significantly influence surface water systems.This study evaluates the hydrochemical characteristics of surface water in the North of Tehran Rivers(NTRs),an essential water resource in a rapidly urbanizing region,using advanced clustering techniques,including Hierarchical Clustering Analysis(HCA),Fuzzy CMeans(FCM),Genetic Algorithm Fuzzy C-Means(GAFCM),and Self-Organizing Map(SOM).The research aims to address the scientific challenge of understanding spatial and temporal variability in water quality,focusing on physicochemical parameters,hydrochemical facies,and contamination sources.Water samples from six rivers collected over four seasons in 2020 were analyzed and classified into distinct clusters based on their chemical composition,revealing significant seasonal and spatial differences.Results showed that FCM and GAFCM consistently categorized the NTRs into two clusters during winter and spring and three in summer and autumn.These findings were supported by HCA and SOM,which identified clusters corresponding to specific river segments and contamination levels.The primary hydrochemical processes identified were mineral dissolution and weathering,with calcite,dolomite,and aragonite significantly influencing water chemistry.Additionally,human activities,such as wastewater discharge,were shown to contribute to elevated sulfate,nitrate,and phosphate concentrations,further corroborated by microbial analyses.By integrating HCA,FCM,and GAFCM with an artificial neural network(ANN)-based clustering method(SOM),this study provides a robust framework for evaluating surface water quality.The findings,supported by Gibbs diagrams,Hounslow ion ratio,and saturation indices,highlight the dominance of rock weathering and human impacts in shaping the hydrochemical dynamics of the NTRs.These insights contribute to the scientific understanding of water quality dynamics and offer practical guidance for sustainable water resource management and environmental protection in developing urban areas.
基金supported by The National Key Research and Development Program of China(Grant No.2023YFB2604600).
文摘In energy constrained application scenarios, self‐powered systems (SPSs) are gradually emerging as a core technological pathway for enabling distributed intelligent sensing. High‐entropy energy, such as micro‐wind, vibrations, water motion, and human activity, is widely available but difficult to harness due to its low density, randomness, and spatiotemporal fragmentation. Triboelectric nanogenerators (TENGs), with high efficiency to low‐frequency and irregular mechanical stimuli, offer a promising solution for efficient energy harvesting, driving the advancement of SPSs with high‐entropy distribution. This review outlines the basic concepts and recent developments of TENG‐driven SPSs, focusing on strategies for energy harvesting, power management, and system integration. It highlights structural optimization and performance enhancement under typical highentropy scenarios and analyzes key challenges in energy conversion, power regulation, and load management. Finally, the potential applications of TENG‐driven SPSs are discussed in emerging smart fields such as infrastructure monitoring, lowaltitude economy, mobile intelligent devices, and ocean sensing networks.
基金financially supported by the National Natural Science Foundation of China(No.52125201)Beijing Natural Science Foundation(No.Z240025)and the Beijing Municipal Science and Technology(No.Z221100002722015).
文摘Flexible and wearable electronics are attracting surging attention due to their potential applications in human health monitoring and precision therapies.Safety hazards including strong magnetic field and electric leakage are big risk factors for human health.It remains challenging to develop self‐powered and wearable safety hazard sensors that could not only be able to monitor human motions but also have functions for detecting potential hazards.In this work,we fabricated a self‐powered,shapeable,and wearable magnetic triboelectric nanogenerator(MTENG)based on ferrofluid,Ecoflex,and carbonized silk fabric that possessed effective hazard prevention and biomechanical motion sensing ability.A peak open‐circuit voltage of 0.7 V and short‐circuit current of 10μA m^(−2)can be achieved when magnetic field is changed between 3.5 and 37.1 mT.As a component of triboelectric layer of the MTENG,ferrofluid can substantially extend the range of its sensing capabilities to many hazardous cues such as dangerous magnetic field.Furtherly,the developed multifunctional and self‐powered sensor can be used to monitor human activities such as drinking water and bending finger.This effort opens up a new design opportunity for hazard avoidance wearable electronics and self‐powered sensors.
文摘On April 2,U.S.President Trump slapped“reciprocal tariffs”on over 100 global trading partners,hitting nine ASEAN member states hard.Alarmingly,even the UN-designated Least Developed Countries(LDCs)were not spared.These included Cambodia,where nearly 20 percent of the population lives below the poverty line,facing a 49 percent tariff;Laos,with a poverty rate near 20 percent,facing 48 percent;and Myanmar,which recently suffered a devastating earthquake,facing 44 percent.
基金National Key Research and Development Program of China,Grant/Award Number:2018YFE0206900China Postdoctoral Science Foundation,Grant/Award Number:2023M731204+2 种基金The Open Project of Key Laboratory for Quality Evaluation of Ultrasound Surgical Equipment of National Medical Products Administration,Grant/Award Number:SMDTKL-2023-1-01The Hubei Province Key Research and Development Project,Grant/Award Number:2023BCB007CAAI-Huawei MindSpore Open Fund。
文摘Convolutional neural network(CNN)with the encoder-decoder structure is popular in medical image segmentation due to its excellent local feature extraction ability but it faces limitations in capturing the global feature.The transformer can extract the global information well but adapting it to small medical datasets is challenging and its computational complexity can be heavy.In this work,a serial and parallel network is proposed for the accurate 3D medical image segmentation by combining CNN and transformer and promoting feature interactions across various semantic levels.The core components of the proposed method include the cross window self-attention based transformer(CWST)and multi-scale local enhanced(MLE)modules.The CWST module enhances the global context understanding by partitioning 3D images into non-overlapping windows and calculating sparse global attention between windows.The MLE module selectively fuses features by computing the voxel attention between different branch features,and uses convolution to strengthen the dense local information.The experiments on the prostate,atrium,and pancreas MR/CT image datasets consistently demonstrate the advantage of the proposed method over six popular segmentation models in both qualitative evaluation and quantitative indexes such as dice similarity coefficient,Intersection over Union,95%Hausdorff distance and average symmetric surface distance.
文摘The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2025B1515020077 and 2024A15150301-39)the National Natural Science Foundation of China(Grant No.12205138)the Shenzhen Science and Technology Innovation Committee(Grant No.JCYJ2022-0530113206015).
文摘We present a minimal theoretical model for self-sustained oscillations of a thin elastic sheet on a hot plate,induced by thermomechanical coupling.As the plate temperature increases,the sheet’s static deflection becomes unstable via a Hopf bifurcation at a critical temperature TC,giving rise to spontaneous periodic motion.Linear stability analysis yields analytical expressions for the critical oscillation temperature TC and the oscillation period at onset.Numerical simulations of the nonlinear equations confirm the bifurcation and reveal how key parameters(stiffness,thermal softening,thermal coupling,etc.)govern the oscillation amplitude and waveform.Finally,we demonstrate that the self-oscillating sheet can perform mechanical work as a heat engine,and we compare its performance to the Carnot efficiency limit.This work provides design principles for thermally driven selfoscillators with potential applications in soft robotics,adaptive structures,and thermal energy harvesting.
基金supported by the National Natural Science Foundation of China(Nos.U2030206,12104022,52271014 and 22075003)the Presidential Foundation of CAEP(No.YZJJZL2023173)Sichuan Science and Technology Program(No.2021YFH0092).
文摘Li/MnO_(2) primary batteries are widely used in industry for their high specific capacity and safety.However,a deep comprehension of the Li^(+)insertion mechanism and the high self-discharge rate of the batteries is still needed.Here,the storage mechanism of Li^(+)in the tunnel structure of MnO_(2) as well as the dissolution and migration of Mn-ions were investigated based on multi-scale approaches.The Li/Mn ratio(at%)is determined at about 0.82 when the discharge voltage decreases to 2 V.The limited Li-ions transport rate in the bulk MnO_(2) restrains the reduction reaction,resulting in a low practical specific capacity.Moreover,utilizing spherical aberration-corrected transmission electron microscopy(TEM)coupled with electron energy loss spectroscopy(EELS),the presence of a mixed valence state layer of Mn^(2+)/Mn^(3+)/Mn^(4+)on the surface of the original 20 nm MnO_(2) particles was identified,which could contribute to the initial dissolution of Mn-ions.The battery separator exhibited channels for Mn-ions migration and diffusion and aggregated Mn particles.We put forward the discharge and degradation route in the ways of Mn-ions trajectories,and our findings provide a deep understanding of the high self-discharge rates and the capacity decay of Li-Mn primary batteries.
基金supported by the National Natural Science Foundation of China(62403393,12202058,62103118)the China Postdoctoral Science Foundation(2021T140160,2023 T160051)the Natural Science Foundation of Chongqing(CSTB 2023NSCQ-MSX0152)
文摘Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous state monitoring. In contrast to the existing self-triggered control method, novel self-triggered mechanism(STM) is proposed by incorporating a waiting time for stabilizing impulses. This allows for direct prediction of the next impulsive instant.
基金supported by the National Natural Science Foundation of China(No.52276094)the Education Project of Hunan Provincial Department(Nos.20B602 and 22C0112)+2 种基金the Industry University Education Cooperation Project(No.230803117185211)the Research Project on Teaching Reform in Ordinary Undergraduate Universities in Hunan Province(No.202401000142)the Natural Science Foundation of Hunan Province(No.2020JJ4935)。
文摘There is limited amount of research on surface plasmon resonance(SPR)sensors with self-referencing capabilities which are based on dielectric gratings.In the short-wavelength range,a metal grating sensor is capable of simultaneously measuring liquid refractive index under proposed temperature.A fabricated gold grating is placed on one side of a thin gold film for refractive index measurement,while the other with polydimethylsiloxane(PDMS)is deposited on the other side for temperature measurement.We use finite element analysis to research its sensing characteristics.Due to the high refractive index sensitivity of SPR sensors and thermo-optic coefficient of PDMS,we discovered the maximum spectral sensitivity of the sensor is 564 nm/RIU and-50 pm/℃when the liquid refractive index ranges from 1.30 to 1.40 with temperature ranging from 0℃ to 100℃.Numerical results indicate that there may not be mutual interference between two channels for measuring refractive index and temperature,which reduces the complexity of sensor measurements.
基金the Innovation 2030-Major Project of Brain Science and Brain-lnspired Intelligence Technology(2021ZD0200600)Shanghai Science and Technology Committee(22YF1439100,YDZX20213100001003)National Natural Science Foundation of China(82201678).
文摘To the editor:Non-suicidal self-injury(NSSI)is an array of directly prepense or repetitive self-harm behaviours without suicidal intent.Individuals engage in self-injurious behaviours to reduce negative mental and cognitive states or evoke positive emotions.
基金supported by #NEXTGENERATIONEU(NGEU)and funded by the Ministry of University and Research(MUR),National Recovery and Resilience Plan(NRRP),project MNESYS(PE0000006)-(DN.155311.10.2022)supported by Sapienza Grant 2021(RM12117A60BDF685).
文摘Background Non-suicidal self-injury(NSSI)is a significant health concern among adolescents and young adults,often resulting from adverse childhood experiences(ACEs).Dissociation,post-traumatic symptoms and attachment style may have a role in shaping such associations.Aims This study aims to provide a unified model of the impact of ACEs on NSSI,exploring complex post-traumatic stress disorder(cPTSD)symptoms and dissociation as potential mediators and the role of the predominant attachment style in affecting such associations.Methods 1010 young individuals attending the last year of high school participated in this cross-sectional study.ACEs,cPTSD,dissociation and NSSI were evaluated using self-report questionnaires.We fitted a path model of NSSI,with ACEs as exogenous variables and cPTSD and dissociation as sequential mediators.Secure,fearful and preoccupied attachment styles were modelled as grouping variables.Results Our findings showed that dissociation mediated the impact of ACEs on NSSI in subjects with a fearful attachment style,as opposed to those with a preoccupied attachment for whom cPTSD symptoms mediated the ACEs-NSSI association.Conclusions Attachment styles moderate the relationship between ACEs and NSSI,with either dissociation or post-traumatic symptomatology mediating the impact of ACEs on NSSI,depending on the predominant attachment style.Our results highlight the importance of attachment as a pathway modifier in the relationships between different psychopathology dimensions,providing a useful framework to better conceptualise the ACEs-NSSI association.
