Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.展开更多
The effects of the structure and concentration of impurities on the alkylation of naphthalene with 1-octene catalyzed by chloroaluminate ionic liquid(IL)were investigated.The presence of impurities containing oxygen a...The effects of the structure and concentration of impurities on the alkylation of naphthalene with 1-octene catalyzed by chloroaluminate ionic liquid(IL)were investigated.The presence of impurities containing oxygen and nitrogen led to a decrease in the catalytic performance of chloroaluminate IL.As the water concentration increased to 65 mg·g^(-1),the total selectivity of multi-octylnaphthalene gradually decreased to 42.33%,and the average friction coefficient of the multi-octylnaphthalene base oil gradually increased to 0.201.When the concentration of impurities increased to a critical value,the chloroaluminate IL began to deactivate,leading to a decrease in naphthalene conversion.The critical concentrations for ethanolamine,water,methanol,ether,and diisopentyl sulfide were 33 mg·g^(-1),65 mg·g^(-1),67mg·g^(-1),87 mg·g^(-1),and 123 mg·g^(-1),respectively.Impurities with higher basicity resulted in an earlier onset of chloroaluminate IL deactivation.The changes of Lewis and Brønsted acids in chloroaluminate IL under the influence of impurities were investigated using in situ IR and 27Al NMR spectroscopy.2,6-dimethylpyridine as an indicator could detect the changes of Brønsted acid in chloroaluminate IL better,but the changes of Lewis acid were not obvious because of the overlap between the characteristic peaks.2,6-dichloropyridine as an indicator could exclusively detect the changes of Lewis acid in chloroaluminate IL.With the increase inwater concentration,the Lewis acid in chloroaluminate IL was continuously consumed and converted into Brønsted acid,and the Lewis acid gradually decreased,while the Brønsted acid showed a change of increasing first and then decreasing.展开更多
Triboelectric nanogenerators(TENGs)offer a selfsustaining power solution for marine regions abundant in resources but constrained by energy availability.Since their pioneering use in wave energy harvesting in 2014,nea...Triboelectric nanogenerators(TENGs)offer a selfsustaining power solution for marine regions abundant in resources but constrained by energy availability.Since their pioneering use in wave energy harvesting in 2014,nearly a decade of advancements has yielded nearly thousands of research articles in this domain.Researchers have developed various TENG device structures with diverse functionalities to facilitate their commercial deployment.Nonetheless,there is a gap in comprehensive summaries and performance evaluations of TENG structural designs.This paper delineates six innovative structural designs,focusing on enhancing internal device output and adapting to external environments:high space utilization,hybrid generator,mechanical gain,broadband response,multi-directional operation,and hybrid energy-harvesting systems.We summarize the prevailing trends in device structure design identified by the research community.Furthermore,we conduct a meticulous comparison of the electrical performance of these devices under motorized,simulated wave,and real marine conditions,while also assessing their sustainability in terms of device durability and mechanical robustness.In conclusion,the paper outlines future research avenues and discusses the obstacles encountered in the TENG field.This review aims to offer valuable perspectives for ongoing research and to advance the progress and application of TENG technology.展开更多
We highly commend Dr Souza et al.1for their systematic review research.The authors conducted a detailed investigation into the effects of ischemic preconditioning(IPC)on athletic performance,comparing it with placebo ...We highly commend Dr Souza et al.1for their systematic review research.The authors conducted a detailed investigation into the effects of ischemic preconditioning(IPC)on athletic performance,comparing it with placebo and no-intervention conditions.The study found that while IPC demonstrated superior effects over the no-intervention group in certain metrics(e.g.,time to exhaustion),its performance did not significantly surpass that of the placebo group.This suggests that the potential benefits of IPC may partially stem from participants’psychological expectations,or placebo effects.The study also highlighted the significant impact of placebo interventions on athletic performance,emphasizing the importance of distinguishing between placebo and no-intervention conditions in experimental designs.展开更多
In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the i...In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the interference signal determines interference cancellation performance,while the auxiliary antenna array affects the correlation by influencing the amplitude and phase of the reference signals.This paper analyzes the effect of auxiliary antenna array on multiple performances of wideband noncooperative interference cancellation.Firstly,the array received signal model of wideband interference is established,and the weight vector coupled with the auxiliary antennas array manifold is solved by spectral analysis and eigen-subspace decomposition.Then,multiple performances which include cancellation resolution,grating null,wideband interference cancellation ratio(ICR),and convergence rate are quantitatively characterized with the auxiliary antenna array.It is obtained through analysis that the performances mutually restrict the auxiliary antenna array.Higher cancellation resolution requires larger array aperture,but when the number of auxiliary antennas is fixed,larger array aperture results in more grating nulls.When the auxiliary antennas are closer to the main antenna,the wideband ICR is improved,but the convergence rate is reduced.The conclusions are verified through simulation of one-dimensional uniform array and two-dimensional nonuniform array.The experiments of three arrays are compared,and the results conform well with simulation and support the theoretical analysis.展开更多
Background:In China,the policy of rotating teachers between urban and rural schools has been implemented to reduce educational disparities and ensure equitable access to quality education.These teachers face unique pr...Background:In China,the policy of rotating teachers between urban and rural schools has been implemented to reduce educational disparities and ensure equitable access to quality education.These teachers face unique professional and emotional challenges during the rotation process,making their emotional labor a critical factor influencing their job performance.This study aimed to explore the relationship between rotating teachers’emotional labor strategies and job performance.Methods:This study conducted a cross-sectional survey among 577 rotating teachers selected through stratified random sampling from primary and secondary schools in Chinese mainland.Date were collected using the Teacher Emotional Labor Scale and the Teacher Job Performance Scale.Latent profile analysis(LPA)was employed to identify distinct categories of emotional labor strategies:indifferent,moderately engaged,naturally invested,proactively adjusted,and emotionally elevated.Results:Teachers in the naturally invested and proactively adjusted types demonstrated relatively higher job performance scores,followed by those in the emotionally elevated type.In contrast,teachers in the indifferent and moderate engagement types exhibited comparatively lower scores(F=25.858,p<0.001,η^(2)=0.153).These findings indicate a practical significance,suggestion that flexible and adaptive use emotional labor strategies is strongly associated with enhanced job performance.Conclusion:This study demonstrates that rotating teachers’job performance differs significantly across distinct emotional labor profiles,with balanced and adaptive emotional regulation emerging as a key determinant of higher performance.By identifying and characterizing individual-centered emotional labor profiles,the study advances understanding of how emotional regulation contributes to teachers’professional effectiveness.These results underscore the importance of providing systematic and personalized support to help rotating teachers develop adaptive emotional regulation skills.Targeted guidance should enable teachers to appropriately express and adjust their emotions,thereby avoiding both excessive and insufficient emotional labor and promoting sustainable professional development.展开更多
We sincerely thank the authors of the commentary1 for their thoughtful analysis and constructive critique of our systematic review on ischemic preconditioning(IPC)and placebo effects in exercise capacity and athletic ...We sincerely thank the authors of the commentary1 for their thoughtful analysis and constructive critique of our systematic review on ischemic preconditioning(IPC)and placebo effects in exercise capacity and athletic performance.2Their attention to methodological details,particularly concerning the inclusion and timing of warm-up protocols across studies,is commendable and contributes meaningfully to the ongoing refinement of IPC research in sports science.展开更多
A novel porous shock absorption layer is put forward in this study, and the shock absorption performance of the porous shock absorption layer is evaluated based on three-dimensional pseudo-static analysis. The modifie...A novel porous shock absorption layer is put forward in this study, and the shock absorption performance of the porous shock absorption layer is evaluated based on three-dimensional pseudo-static analysis. The modified reaction acceleration method is adopted and validated in the three-dimensional model. Seven ground motions are selected and the peak ground acceleration is adjusted to 0.2 g, 0.4 g and 0.6 g. The impact of the void ratio and thickness of the porous shock absorption layer is studied, while the surrounding rock grade and tunnel depth are also investigated. The numerical results show that the porous shock absorption layer has good shock absorption performance and can effectively reduce the maximum internal force of the secondary lining, but it cannot reduce the maximum horizontal relative displacement of the secondary lining. The circumferential rubber strip in the porous shock absorption layer will reduce shock absorption performance. The results of parameter analysis indicate that the shock absorption performance of the porous shock absorption layer increases with the increase of the void ratio and thickness, and it has good shock absorption performance under different surrounding rock grades and tunnel depths.展开更多
Due to uncertainties in seismic pipeline damage and post-earthquake recovery processes,probabilistic characteristics such as mean value,standard deviation,probability density function,and cumulative distribution funct...Due to uncertainties in seismic pipeline damage and post-earthquake recovery processes,probabilistic characteristics such as mean value,standard deviation,probability density function,and cumulative distribution function provide valuable information.In this study,a simulation-based framework to evaluate these probabilistic characteristics in water distribution systems(WDSs)during post-earthquake recovery is developed.The framework first calculates pipeline failure probabilities using seismic fragility models and then generates damage samples through quasi-Monte Carlo simulations with Sobol’s sequence for faster convergence.System performance is assessed using a hydraulic model,and recovery simulations produce time-varying performance curves,where the dynamic importance of unrepaired damage determines repair sequences.Finally,the probabilistic characteristics of seismic performance indicators,resilience index,resilience loss,and recovery time are evaluated.The framework is applied in two benchmark WDSs with different layouts to investigate the probabilistic characteristics of their seismic performance and resilience.Application results show that the cumulative distribution function reveals the variations in resilience indicators for different exceedance probabilities,and there are dramatic differences among the recovery times corresponding to the system performance recovery targets of 80%,90%,and 100%.展开更多
This paper studies the sensing base station(SBS)that has great potential to improve the safety of vehicles and pedestrians on roads.SBS can detect the targets on the road with communication signals using the integrate...This paper studies the sensing base station(SBS)that has great potential to improve the safety of vehicles and pedestrians on roads.SBS can detect the targets on the road with communication signals using the integrated sensing and communication(ISAC)technique.Compared with vehicle-mounted radar,SBS has a better sensing field due to its higher deployment position,which can help solve the problem of sensing blind areas.In this paper,key technologies of SBS are studied,including the beamforming algorithm,beam scanning scheme,and interference cancellation algorithm.To transmit and receive ISAC signals simultaneously,a double-coupling antenna array is applied.The free detection beam and directional communication beam are proposed for joint communication and sensing to meet the requirements of beamwidth and pointing directions.The joint timespace-frequency domain division multiple access algorithm is proposed to cancel the interference of SBS,including multiuser interference and duplex interference between sensing and communication.Finally,the sensing and communication performance of SBS under the industrial scientific medical power limitation is analyzed and simulated.Simulation results show that the communication rate of SBS can reach over 100 Mbps and the range of sensing and communication can reach about 500 m.展开更多
A novel precipitate-free Mg-0.1Sn anode with a homogeneous equal-axis grain structure was developed and rolled successfully at 573 K.Electrochemical test results indicate that the Mg-0.1Sn alloy exhibits enhanced anod...A novel precipitate-free Mg-0.1Sn anode with a homogeneous equal-axis grain structure was developed and rolled successfully at 573 K.Electrochemical test results indicate that the Mg-0.1Sn alloy exhibits enhanced anode dissolution kinetics.A Mg-air battery prepared using this anode exhibits a cell voltage of 1.626 V at 0.5 mA/cm^(2),reasonable anodic efficiency of 58.17%,and good specific energy of 1730.96 mW·h/g at 10 mA/cm^(2).This performance is attributed to the effective reactive anode surface,the suppressed chunk effect,and weak self-corrosion owing to the homogeneous basal texture.展开更多
In this commentary,we respond to Zhao et al’s recent paper which focuses on mechanisms underlying insomnia sufferers’engagement with acupuncture.Insomnia,a prevalent condition characterized by difficulty falling asl...In this commentary,we respond to Zhao et al’s recent paper which focuses on mechanisms underlying insomnia sufferers’engagement with acupuncture.Insomnia,a prevalent condition characterized by difficulty falling asleep and poor sleep quality,is associated with increased risk of cardiovascular disease,diabetes,and psychiatric illness.Acupuncture,a method involving the therapeutic placement of needles,has been widely accepted as a treatment for insomnia with minimal side effects.In fact,clinical trials suggest auricular acupuncture may improve sleep duration more than cognitive behavioral therapy.However,responses to acupuncture vary.Some patients find it extremely beneficial,while others view it as a routine treatment—or avoid it altogether due to needle phobia.Patient engagement is influenced by cultural beliefs,encouragement,motivation,prior experiences,and recommendations from peers or clinicians.Trust in the physician and testimonials from recovered patients are particularly important facilitators.Looking ahead,a holistic approach-integrating acupuncture with meditation,pranayama,yoga,and other restorative practices-may enhance treatment effectiveness and help patients achieve restorative sleep.展开更多
Ransomware is malware that encrypts data without permission,demanding payment for access.Detecting ransomware on Android platforms is challenging due to evolving malicious techniques and diverse application behaviors....Ransomware is malware that encrypts data without permission,demanding payment for access.Detecting ransomware on Android platforms is challenging due to evolving malicious techniques and diverse application behaviors.Traditional methods,such as static and dynamic analysis,suffer from polymorphism,code obfuscation,and high resource demands.This paper introduces a multi-stage approach to enhance behavioral analysis for Android ransomware detection,focusing on a reduced set of distinguishing features.The approach includes ransomware app collection,behavioral profile generation,dataset creation,feature identification,reduction,and classification.Experiments were conducted on∼3300 Android-based ransomware samples,despite the challenges posed by their evolving nature and complexity.The feature reduction strategy successfully reduced features by 80%,with only a marginal loss of detection accuracy(0.59%).Different machine learning algorithms are employed for classification and achieve 96.71%detection accuracy.Additionally,10-fold cross-validation demonstrated robustness,yielding an AUC-ROC of 99.3%.Importantly,latency and memory evaluations revealed that models using the reduced feature set achieved up to a 99%reduction in inference time and significant memory savings across classifiers.The proposed approach outperforms existing techniques by achieving high detection accuracy with a minimal feature set,also suitable for deployment in resource-constrained environments.Future work may extend datasets and include iOS-based ransomware applications.展开更多
The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of var...The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of varied pre-aging states of NiTi particles into the 5052Al matrix using a rolling composite technique.The aim is to enhance the application scope of aluminum alloy for vibration and noise reduction.The results demonstrated a distinct and integrated interface between the particle layer and the 5052Al alloy,with numerous interparticle interfaces within the particle layer.Increasing the aging temperature of the NiTi particles from 450 to 550℃ shifted the phase transition peaks of the composites to lower temperatures.The damping capacity of the laminated NiTip/5052Al composites notably surpasses that of the 5052Al alloy.At 28 and 66℃,the phase transformation damping peaks of the pre-aged NiTi particle layer reinforced 5052Al matrix composites are 1.93 and 2 times those of the 5052Al alloy at the corresponding temperatures,respectively.The collaborative impact of interparticle interface damping mechanism and the phase transformation damping mechanism of NiTi-reinforced particles significantly amplify the low-temperature damping performance of the laminated NiTip/5052Al composites.展开更多
We explored the relationship between Internet altruistic behavior(IAB)and subjective well-being(SWB)to estimate the effects and directionality of that predictive relationship between the two.Employing cross-lagged mod...We explored the relationship between Internet altruistic behavior(IAB)and subjective well-being(SWB)to estimate the effects and directionality of that predictive relationship between the two.Employing cross-lagged models we examined the interaction between IAB and SWB,among 339 college students(females=53.10%,mean age=19.02 years,SD=1.56 years).The students were tracked twice in a period of 5 months.Results showed that college students’IAB increased significantly,while their SWB remained relatively stable during the two measurement periods.IAB and SWB had significant simultaneous and sequential correlations.SWB at Time 1 positively predicted IAB at Time 2,however,IAB at Time 1 did not significantly predict SWB at Time 2.Moreover,there was cross-gender invariance in the cross-lagged effect between IAB and SWB.Research topics in the current environment exhibit remarkable practical significance.展开更多
With the rapid development of the Internet and e-commerce,e-commerce platforms have accumulated huge amounts of user behavior data.The emergence of big data technology provides a powerful means for in-depth analysis o...With the rapid development of the Internet and e-commerce,e-commerce platforms have accumulated huge amounts of user behavior data.The emergence of big data technology provides a powerful means for in-depth analysis of these data and insight into user behavior patterns and preferences.This paper elaborates on the application of big data technology in the analysis of user behavior on e-commerce platforms,including the technical methods of data collection,storage,processing and analysis,as well as the specific applications in the construction of user profiles,precision marketing,personalized recommendation,user retention and churn analysis,etc.,and discusses the challenges and countermeasures faced in the application.Through the study of actual cases,it demonstrates the remarkable effectiveness of big data technology in enhancing the competitiveness of e-commerce platforms and user experience.展开更多
Employees’innovative performance determines an organization’s innovation,which critically impacts its structural optimization and sustainability.Applying expectancy theory,we examined how and when the Pygmalion effe...Employees’innovative performance determines an organization’s innovation,which critically impacts its structural optimization and sustainability.Applying expectancy theory,we examined how and when the Pygmalion effect occurs in the relationship between leaders’expectations of innovation and employee innovative behavior.Our sample comprised 201 frontline employees(female=31.84%;mean age=41.48 years,SD=7.97 years)in a Chinese coal enterprise,who completed surveys on innovation expectations of leaders,expected positive performance outcomes,innovative self-efficacy and innovative behavior.The results revealed that employees’expected positive performance outcomes mediated the positive relationship between leaders’innovation expectations and their innovative behavior.Employees’innovative self-efficacy positively moderated the relationship between their expected positive performance outcomes and innovative behavior,with this relationship being stronger for employees with high innovative self-efficacy.Moreover,we validated the moderated mediation model.Findings suggest that leaders can stimulate employee innovative behavior through expressing expectations and they also need to consider the boundary conditions.展开更多
Advancements in animal behavior quantification methods have driven the development of computational ethology,enabling fully automated behavior analysis.Existing multianimal pose estimation workflows rely on tracking-b...Advancements in animal behavior quantification methods have driven the development of computational ethology,enabling fully automated behavior analysis.Existing multianimal pose estimation workflows rely on tracking-bydetection frameworks for either bottom-up or top-down approaches,requiring retraining to accommodate diverse animal appearances.This study introduces InteBOMB,an integrated workflow that enhances top-down approaches by incorporating generic object tracking,eliminating the need for prior knowledge of target animals while maintaining broad generalizability.InteBOMB includes two key strategies for tracking and segmentation in laboratory environments and two techniques for pose estimation in natural settings.The“background enhancement”strategy optimizesforeground-backgroundcontrastiveloss,generating more discriminative correlation maps.The“online proofreading”strategy stores human-in-the-loop long-term memory and dynamic short-term memory,enabling adaptive updates to object visual features.The“automated labeling suggestion”technique reuses the visual features saved during tracking to identify representative frames for training set labeling.Additionally,the“joint behavior analysis”technique integrates these features with multimodal data,expanding the latent space for behavior classification and clustering.To evaluate the framework,six datasets of mice and six datasets of nonhuman primates were compiled,covering laboratory and natural scenes.Benchmarking results demonstrated a24%improvement in zero-shot generic tracking and a 21%enhancement in joint latent space performance across datasets,highlighting the effectiveness of this approach in robust,generalizable behavior analysis.展开更多
This paper presents a novel suspension support tailored for wind tunnel tests of spinning projectiles based on Wire-Driven Parallel Robot(WDPR),uniquely characterized by an SPM(Spinning Projectile Model)-centered mobi...This paper presents a novel suspension support tailored for wind tunnel tests of spinning projectiles based on Wire-Driven Parallel Robot(WDPR),uniquely characterized by an SPM(Spinning Projectile Model)-centered mobile platform.First,an SPM-centered mobile platform,featuring two redundant and another unconstrained Degree of Freedom(DOF),and its suspension support mechanism are designed together,collectively constructing a WDPR endowed with kinematic redundancy.Afterward,the kinematics of the mechanism,boundary equations for the redundant DOFs,and relevant kinematic performance indices are then proposed and formulated.The results from both prototype experiments and numerical assessments are presented.The capability of the support mechanism to replicate the complex coupled motions of the SPM is verified by the experimental results,while the proposed kinematics and boundary equations are also validated.Furthermore,it is revealed by numerical assessments that the redundant DOFs of the mobile platform exert a minimal impact on the kinematic performance of the suspension support.Finally,the optimal global attitude performance is obtained when these DOFs are set to zero if they are restricted to constants.However,local attitude performance can be further improved by the variable values.展开更多
Integrated data and energy transfer(IDET)enables the electromagnetic waves to transmit wireless energy at the same time of data delivery for lowpower devices.In this paper,an energy harvesting modulation(EHM)assisted ...Integrated data and energy transfer(IDET)enables the electromagnetic waves to transmit wireless energy at the same time of data delivery for lowpower devices.In this paper,an energy harvesting modulation(EHM)assisted multi-user IDET system is studied,where all the received signals at the users are exploited for energy harvesting without the degradation of wireless data transfer(WDT)performance.The joint IDET performance is then analysed theoretically by conceiving a practical time-dependent wireless channel.With the aid of the AO based algorithm,the average effective data rate among users are maximized by ensuring the BER and the wireless energy transfer(WET)performance.Simulation results validate and evaluate the IDET performance of the EHM assisted system,which also demonstrates that the optimal number of user clusters and IDET time slots should be allocated,in order to improve the WET and WDT performance.展开更多
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
基金financial support of the Scientific Research Funds of Huaqiao University (605-50Y17073)
文摘The effects of the structure and concentration of impurities on the alkylation of naphthalene with 1-octene catalyzed by chloroaluminate ionic liquid(IL)were investigated.The presence of impurities containing oxygen and nitrogen led to a decrease in the catalytic performance of chloroaluminate IL.As the water concentration increased to 65 mg·g^(-1),the total selectivity of multi-octylnaphthalene gradually decreased to 42.33%,and the average friction coefficient of the multi-octylnaphthalene base oil gradually increased to 0.201.When the concentration of impurities increased to a critical value,the chloroaluminate IL began to deactivate,leading to a decrease in naphthalene conversion.The critical concentrations for ethanolamine,water,methanol,ether,and diisopentyl sulfide were 33 mg·g^(-1),65 mg·g^(-1),67mg·g^(-1),87 mg·g^(-1),and 123 mg·g^(-1),respectively.Impurities with higher basicity resulted in an earlier onset of chloroaluminate IL deactivation.The changes of Lewis and Brønsted acids in chloroaluminate IL under the influence of impurities were investigated using in situ IR and 27Al NMR spectroscopy.2,6-dimethylpyridine as an indicator could detect the changes of Brønsted acid in chloroaluminate IL better,but the changes of Lewis acid were not obvious because of the overlap between the characteristic peaks.2,6-dichloropyridine as an indicator could exclusively detect the changes of Lewis acid in chloroaluminate IL.With the increase inwater concentration,the Lewis acid in chloroaluminate IL was continuously consumed and converted into Brønsted acid,and the Lewis acid gradually decreased,while the Brønsted acid showed a change of increasing first and then decreasing.
基金supported by the National Key R&D Project from Ministry of Science and Technology,China(2021YFA1201603)National Natural Science Foundation of China(52073032 and 52192611)the Fundamental Research Funds for the Central Universities.
文摘Triboelectric nanogenerators(TENGs)offer a selfsustaining power solution for marine regions abundant in resources but constrained by energy availability.Since their pioneering use in wave energy harvesting in 2014,nearly a decade of advancements has yielded nearly thousands of research articles in this domain.Researchers have developed various TENG device structures with diverse functionalities to facilitate their commercial deployment.Nonetheless,there is a gap in comprehensive summaries and performance evaluations of TENG structural designs.This paper delineates six innovative structural designs,focusing on enhancing internal device output and adapting to external environments:high space utilization,hybrid generator,mechanical gain,broadband response,multi-directional operation,and hybrid energy-harvesting systems.We summarize the prevailing trends in device structure design identified by the research community.Furthermore,we conduct a meticulous comparison of the electrical performance of these devices under motorized,simulated wave,and real marine conditions,while also assessing their sustainability in terms of device durability and mechanical robustness.In conclusion,the paper outlines future research avenues and discusses the obstacles encountered in the TENG field.This review aims to offer valuable perspectives for ongoing research and to advance the progress and application of TENG technology.
文摘We highly commend Dr Souza et al.1for their systematic review research.The authors conducted a detailed investigation into the effects of ischemic preconditioning(IPC)on athletic performance,comparing it with placebo and no-intervention conditions.The study found that while IPC demonstrated superior effects over the no-intervention group in certain metrics(e.g.,time to exhaustion),its performance did not significantly surpass that of the placebo group.This suggests that the potential benefits of IPC may partially stem from participants’psychological expectations,or placebo effects.The study also highlighted the significant impact of placebo interventions on athletic performance,emphasizing the importance of distinguishing between placebo and no-intervention conditions in experimental designs.
基金supported by the National Fund for Distinguished Young Scholars(52025072)the National Natural Science Foundation of China(52177012)the Foundation of National Key Laboratory of Science and Technology(614221722051301).
文摘In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the interference signal determines interference cancellation performance,while the auxiliary antenna array affects the correlation by influencing the amplitude and phase of the reference signals.This paper analyzes the effect of auxiliary antenna array on multiple performances of wideband noncooperative interference cancellation.Firstly,the array received signal model of wideband interference is established,and the weight vector coupled with the auxiliary antennas array manifold is solved by spectral analysis and eigen-subspace decomposition.Then,multiple performances which include cancellation resolution,grating null,wideband interference cancellation ratio(ICR),and convergence rate are quantitatively characterized with the auxiliary antenna array.It is obtained through analysis that the performances mutually restrict the auxiliary antenna array.Higher cancellation resolution requires larger array aperture,but when the number of auxiliary antennas is fixed,larger array aperture results in more grating nulls.When the auxiliary antennas are closer to the main antenna,the wideband ICR is improved,but the convergence rate is reduced.The conclusions are verified through simulation of one-dimensional uniform array and two-dimensional nonuniform array.The experiments of three arrays are compared,and the results conform well with simulation and support the theoretical analysis.
基金funded by the Postdoctoral Fellowship Program of CPSF(China),grant number GZ20232369.No part of the study(design,data collection,and curation analysis,manuscript preparation or publication)was influenced by the funder.
文摘Background:In China,the policy of rotating teachers between urban and rural schools has been implemented to reduce educational disparities and ensure equitable access to quality education.These teachers face unique professional and emotional challenges during the rotation process,making their emotional labor a critical factor influencing their job performance.This study aimed to explore the relationship between rotating teachers’emotional labor strategies and job performance.Methods:This study conducted a cross-sectional survey among 577 rotating teachers selected through stratified random sampling from primary and secondary schools in Chinese mainland.Date were collected using the Teacher Emotional Labor Scale and the Teacher Job Performance Scale.Latent profile analysis(LPA)was employed to identify distinct categories of emotional labor strategies:indifferent,moderately engaged,naturally invested,proactively adjusted,and emotionally elevated.Results:Teachers in the naturally invested and proactively adjusted types demonstrated relatively higher job performance scores,followed by those in the emotionally elevated type.In contrast,teachers in the indifferent and moderate engagement types exhibited comparatively lower scores(F=25.858,p<0.001,η^(2)=0.153).These findings indicate a practical significance,suggestion that flexible and adaptive use emotional labor strategies is strongly associated with enhanced job performance.Conclusion:This study demonstrates that rotating teachers’job performance differs significantly across distinct emotional labor profiles,with balanced and adaptive emotional regulation emerging as a key determinant of higher performance.By identifying and characterizing individual-centered emotional labor profiles,the study advances understanding of how emotional regulation contributes to teachers’professional effectiveness.These results underscore the importance of providing systematic and personalized support to help rotating teachers develop adaptive emotional regulation skills.Targeted guidance should enable teachers to appropriately express and adjust their emotions,thereby avoiding both excessive and insufficient emotional labor and promoting sustainable professional development.
文摘We sincerely thank the authors of the commentary1 for their thoughtful analysis and constructive critique of our systematic review on ischemic preconditioning(IPC)and placebo effects in exercise capacity and athletic performance.2Their attention to methodological details,particularly concerning the inclusion and timing of warm-up protocols across studies,is commendable and contributes meaningfully to the ongoing refinement of IPC research in sports science.
基金Science and Technology Plan Project of Xizang Autonomous Region,China under Grant No.XZ202501YD0007。
文摘A novel porous shock absorption layer is put forward in this study, and the shock absorption performance of the porous shock absorption layer is evaluated based on three-dimensional pseudo-static analysis. The modified reaction acceleration method is adopted and validated in the three-dimensional model. Seven ground motions are selected and the peak ground acceleration is adjusted to 0.2 g, 0.4 g and 0.6 g. The impact of the void ratio and thickness of the porous shock absorption layer is studied, while the surrounding rock grade and tunnel depth are also investigated. The numerical results show that the porous shock absorption layer has good shock absorption performance and can effectively reduce the maximum internal force of the secondary lining, but it cannot reduce the maximum horizontal relative displacement of the secondary lining. The circumferential rubber strip in the porous shock absorption layer will reduce shock absorption performance. The results of parameter analysis indicate that the shock absorption performance of the porous shock absorption layer increases with the increase of the void ratio and thickness, and it has good shock absorption performance under different surrounding rock grades and tunnel depths.
基金National Key R&D Program of China under Grant No.2022YFC3003600National Natural Science Foundation of China(NSFC)under Grant No.51978023。
文摘Due to uncertainties in seismic pipeline damage and post-earthquake recovery processes,probabilistic characteristics such as mean value,standard deviation,probability density function,and cumulative distribution function provide valuable information.In this study,a simulation-based framework to evaluate these probabilistic characteristics in water distribution systems(WDSs)during post-earthquake recovery is developed.The framework first calculates pipeline failure probabilities using seismic fragility models and then generates damage samples through quasi-Monte Carlo simulations with Sobol’s sequence for faster convergence.System performance is assessed using a hydraulic model,and recovery simulations produce time-varying performance curves,where the dynamic importance of unrepaired damage determines repair sequences.Finally,the probabilistic characteristics of seismic performance indicators,resilience index,resilience loss,and recovery time are evaluated.The framework is applied in two benchmark WDSs with different layouts to investigate the probabilistic characteristics of their seismic performance and resilience.Application results show that the cumulative distribution function reveals the variations in resilience indicators for different exceedance probabilities,and there are dramatic differences among the recovery times corresponding to the system performance recovery targets of 80%,90%,and 100%.
基金supported in part by the National Natural Science Foundation of China under Grant U21B2014,Grant 92267202,and Grant 62271081.
文摘This paper studies the sensing base station(SBS)that has great potential to improve the safety of vehicles and pedestrians on roads.SBS can detect the targets on the road with communication signals using the integrated sensing and communication(ISAC)technique.Compared with vehicle-mounted radar,SBS has a better sensing field due to its higher deployment position,which can help solve the problem of sensing blind areas.In this paper,key technologies of SBS are studied,including the beamforming algorithm,beam scanning scheme,and interference cancellation algorithm.To transmit and receive ISAC signals simultaneously,a double-coupling antenna array is applied.The free detection beam and directional communication beam are proposed for joint communication and sensing to meet the requirements of beamwidth and pointing directions.The joint timespace-frequency domain division multiple access algorithm is proposed to cancel the interference of SBS,including multiuser interference and duplex interference between sensing and communication.Finally,the sensing and communication performance of SBS under the industrial scientific medical power limitation is analyzed and simulated.Simulation results show that the communication rate of SBS can reach over 100 Mbps and the range of sensing and communication can reach about 500 m.
基金partially supported by the National Natural Science Foundation of China(No.51901153)Shanxi Scholarship Council of China(No.2019032)+1 种基金the Natural Science Foundation of Shanxi,China(No.202103021224049)the Shanxi Zhejiang University New Materials and Chemical Research Institute Scientific Research Project,China(No.2022SX-TD025)。
文摘A novel precipitate-free Mg-0.1Sn anode with a homogeneous equal-axis grain structure was developed and rolled successfully at 573 K.Electrochemical test results indicate that the Mg-0.1Sn alloy exhibits enhanced anode dissolution kinetics.A Mg-air battery prepared using this anode exhibits a cell voltage of 1.626 V at 0.5 mA/cm^(2),reasonable anodic efficiency of 58.17%,and good specific energy of 1730.96 mW·h/g at 10 mA/cm^(2).This performance is attributed to the effective reactive anode surface,the suppressed chunk effect,and weak self-corrosion owing to the homogeneous basal texture.
文摘In this commentary,we respond to Zhao et al’s recent paper which focuses on mechanisms underlying insomnia sufferers’engagement with acupuncture.Insomnia,a prevalent condition characterized by difficulty falling asleep and poor sleep quality,is associated with increased risk of cardiovascular disease,diabetes,and psychiatric illness.Acupuncture,a method involving the therapeutic placement of needles,has been widely accepted as a treatment for insomnia with minimal side effects.In fact,clinical trials suggest auricular acupuncture may improve sleep duration more than cognitive behavioral therapy.However,responses to acupuncture vary.Some patients find it extremely beneficial,while others view it as a routine treatment—or avoid it altogether due to needle phobia.Patient engagement is influenced by cultural beliefs,encouragement,motivation,prior experiences,and recommendations from peers or clinicians.Trust in the physician and testimonials from recovered patients are particularly important facilitators.Looking ahead,a holistic approach-integrating acupuncture with meditation,pranayama,yoga,and other restorative practices-may enhance treatment effectiveness and help patients achieve restorative sleep.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2021R1I1A3049788).
文摘Ransomware is malware that encrypts data without permission,demanding payment for access.Detecting ransomware on Android platforms is challenging due to evolving malicious techniques and diverse application behaviors.Traditional methods,such as static and dynamic analysis,suffer from polymorphism,code obfuscation,and high resource demands.This paper introduces a multi-stage approach to enhance behavioral analysis for Android ransomware detection,focusing on a reduced set of distinguishing features.The approach includes ransomware app collection,behavioral profile generation,dataset creation,feature identification,reduction,and classification.Experiments were conducted on∼3300 Android-based ransomware samples,despite the challenges posed by their evolving nature and complexity.The feature reduction strategy successfully reduced features by 80%,with only a marginal loss of detection accuracy(0.59%).Different machine learning algorithms are employed for classification and achieve 96.71%detection accuracy.Additionally,10-fold cross-validation demonstrated robustness,yielding an AUC-ROC of 99.3%.Importantly,latency and memory evaluations revealed that models using the reduced feature set achieved up to a 99%reduction in inference time and significant memory savings across classifiers.The proposed approach outperforms existing techniques by achieving high detection accuracy with a minimal feature set,also suitable for deployment in resource-constrained environments.Future work may extend datasets and include iOS-based ransomware applications.
基金National Natural Science Foundation of China (No. 52061011)Guangxi Natural Science Foundation,China (No. 2022GXNSFAA035574)Innovation Project of Guangxi Graduate Education,China (No. YCSW2023361)。
文摘The insufficient damping capabilities of aluminum alloy under low temperatures(<120℃)were addressed by developing high-damping laminated composites of NiTip/5052Al.This is achieved through the incorporation of varied pre-aging states of NiTi particles into the 5052Al matrix using a rolling composite technique.The aim is to enhance the application scope of aluminum alloy for vibration and noise reduction.The results demonstrated a distinct and integrated interface between the particle layer and the 5052Al alloy,with numerous interparticle interfaces within the particle layer.Increasing the aging temperature of the NiTi particles from 450 to 550℃ shifted the phase transition peaks of the composites to lower temperatures.The damping capacity of the laminated NiTip/5052Al composites notably surpasses that of the 5052Al alloy.At 28 and 66℃,the phase transformation damping peaks of the pre-aged NiTi particle layer reinforced 5052Al matrix composites are 1.93 and 2 times those of the 5052Al alloy at the corresponding temperatures,respectively.The collaborative impact of interparticle interface damping mechanism and the phase transformation damping mechanism of NiTi-reinforced particles significantly amplify the low-temperature damping performance of the laminated NiTip/5052Al composites.
基金supported by the Yizhou Organization Management Research Fund and the Hainan Province Graduate Student Innovation Research Project(grant no.Qhyb2024-135).
文摘We explored the relationship between Internet altruistic behavior(IAB)and subjective well-being(SWB)to estimate the effects and directionality of that predictive relationship between the two.Employing cross-lagged models we examined the interaction between IAB and SWB,among 339 college students(females=53.10%,mean age=19.02 years,SD=1.56 years).The students were tracked twice in a period of 5 months.Results showed that college students’IAB increased significantly,while their SWB remained relatively stable during the two measurement periods.IAB and SWB had significant simultaneous and sequential correlations.SWB at Time 1 positively predicted IAB at Time 2,however,IAB at Time 1 did not significantly predict SWB at Time 2.Moreover,there was cross-gender invariance in the cross-lagged effect between IAB and SWB.Research topics in the current environment exhibit remarkable practical significance.
文摘With the rapid development of the Internet and e-commerce,e-commerce platforms have accumulated huge amounts of user behavior data.The emergence of big data technology provides a powerful means for in-depth analysis of these data and insight into user behavior patterns and preferences.This paper elaborates on the application of big data technology in the analysis of user behavior on e-commerce platforms,including the technical methods of data collection,storage,processing and analysis,as well as the specific applications in the construction of user profiles,precision marketing,personalized recommendation,user retention and churn analysis,etc.,and discusses the challenges and countermeasures faced in the application.Through the study of actual cases,it demonstrates the remarkable effectiveness of big data technology in enhancing the competitiveness of e-commerce platforms and user experience.
基金funded by“National Natural Science Foundation of China”grant number[71872119]“Shanxi Provincial Government Major Decision-making Consulting Project”grant number[ZB20240114]The APC was funded by“Shanxi Provincial Government Major Decision-making Consulting Project”grant number[ZB20240114].
文摘Employees’innovative performance determines an organization’s innovation,which critically impacts its structural optimization and sustainability.Applying expectancy theory,we examined how and when the Pygmalion effect occurs in the relationship between leaders’expectations of innovation and employee innovative behavior.Our sample comprised 201 frontline employees(female=31.84%;mean age=41.48 years,SD=7.97 years)in a Chinese coal enterprise,who completed surveys on innovation expectations of leaders,expected positive performance outcomes,innovative self-efficacy and innovative behavior.The results revealed that employees’expected positive performance outcomes mediated the positive relationship between leaders’innovation expectations and their innovative behavior.Employees’innovative self-efficacy positively moderated the relationship between their expected positive performance outcomes and innovative behavior,with this relationship being stronger for employees with high innovative self-efficacy.Moreover,we validated the moderated mediation model.Findings suggest that leaders can stimulate employee innovative behavior through expressing expectations and they also need to consider the boundary conditions.
基金supported by the STI 2030-Major Projects(2022ZD0211900,2022ZD0211902)STI 2030-Major Projects(2021ZD0204500,2021ZD0204503)+1 种基金National Natural Science Foundation of China(32171461)National Key Research and Development Program of China(2023YFC3208303)。
文摘Advancements in animal behavior quantification methods have driven the development of computational ethology,enabling fully automated behavior analysis.Existing multianimal pose estimation workflows rely on tracking-bydetection frameworks for either bottom-up or top-down approaches,requiring retraining to accommodate diverse animal appearances.This study introduces InteBOMB,an integrated workflow that enhances top-down approaches by incorporating generic object tracking,eliminating the need for prior knowledge of target animals while maintaining broad generalizability.InteBOMB includes two key strategies for tracking and segmentation in laboratory environments and two techniques for pose estimation in natural settings.The“background enhancement”strategy optimizesforeground-backgroundcontrastiveloss,generating more discriminative correlation maps.The“online proofreading”strategy stores human-in-the-loop long-term memory and dynamic short-term memory,enabling adaptive updates to object visual features.The“automated labeling suggestion”technique reuses the visual features saved during tracking to identify representative frames for training set labeling.Additionally,the“joint behavior analysis”technique integrates these features with multimodal data,expanding the latent space for behavior classification and clustering.To evaluate the framework,six datasets of mice and six datasets of nonhuman primates were compiled,covering laboratory and natural scenes.Benchmarking results demonstrated a24%improvement in zero-shot generic tracking and a 21%enhancement in joint latent space performance across datasets,highlighting the effectiveness of this approach in robust,generalizable behavior analysis.
基金supported by the National Natural Science Foundation of China(No.12072304).
文摘This paper presents a novel suspension support tailored for wind tunnel tests of spinning projectiles based on Wire-Driven Parallel Robot(WDPR),uniquely characterized by an SPM(Spinning Projectile Model)-centered mobile platform.First,an SPM-centered mobile platform,featuring two redundant and another unconstrained Degree of Freedom(DOF),and its suspension support mechanism are designed together,collectively constructing a WDPR endowed with kinematic redundancy.Afterward,the kinematics of the mechanism,boundary equations for the redundant DOFs,and relevant kinematic performance indices are then proposed and formulated.The results from both prototype experiments and numerical assessments are presented.The capability of the support mechanism to replicate the complex coupled motions of the SPM is verified by the experimental results,while the proposed kinematics and boundary equations are also validated.Furthermore,it is revealed by numerical assessments that the redundant DOFs of the mobile platform exert a minimal impact on the kinematic performance of the suspension support.Finally,the optimal global attitude performance is obtained when these DOFs are set to zero if they are restricted to constants.However,local attitude performance can be further improved by the variable values.
基金supported in part by the MOST Major Research and Development Project(Grant No.2021YFB2900204)the National Natural Science Foundation of China(NSFC)(Grant No.62201123,No.62132004,No.61971102)+3 种基金China Postdoctoral Science Foundation(Grant No.2022TQ0056)in part by the financial support of the Sichuan Science and Technology Program(Grant No.2022YFH0022)Sichuan Major R&D Project(Grant No.22QYCX0168)the Municipal Government of Quzhou(Grant No.2022D031)。
文摘Integrated data and energy transfer(IDET)enables the electromagnetic waves to transmit wireless energy at the same time of data delivery for lowpower devices.In this paper,an energy harvesting modulation(EHM)assisted multi-user IDET system is studied,where all the received signals at the users are exploited for energy harvesting without the degradation of wireless data transfer(WDT)performance.The joint IDET performance is then analysed theoretically by conceiving a practical time-dependent wireless channel.With the aid of the AO based algorithm,the average effective data rate among users are maximized by ensuring the BER and the wireless energy transfer(WET)performance.Simulation results validate and evaluate the IDET performance of the EHM assisted system,which also demonstrates that the optimal number of user clusters and IDET time slots should be allocated,in order to improve the WET and WDT performance.
