Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.Th...Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.This study introduces a composite denoising approach to address this challenge.This method is based on the ameliorated ellipse fitting algorithm(AEFA)and adaptive successive variational mode decomposition(ASVMD).This algorithm employs AEFA to eliminate system noise tightly coupled with direct-current and alternating-current components in the interference signal,thereby obtaining a phase signal containing only environmental noise.The ASVMD technique adaptively extracts environmental noise components predominantly present in the phase signal.To achieve optimal decomposition results automatically,the permutation entropy criterion is employed to refine decomposition parameters.The correlation coefficient is utilized to differentiate effective components from noise components in the decomposition results.Experimental results indicate that the combined AEFA and ASVMD algorithm effectively suppresses both system and environmental noises.When applied to 50 Hz vibration signal processing,the proposed approach achieves a noise reduction of 17.81 dB and a phase resolution of 35.14μrad/√Hz.Given the excellent performance of the noise suppression,the proposed approach holds great application potential in high-performance interferometric sensing systems.展开更多
With the integration of large-scale renewable energy sources(RESs),the line commutated converter(LCC)based high-voltage direct-current(HVDC)inverter side suffers from degraded grid strength and escalating commutation ...With the integration of large-scale renewable energy sources(RESs),the line commutated converter(LCC)based high-voltage direct-current(HVDC)inverter side suffers from degraded grid strength and escalating commutation failure(CF)risks.In comparison with the widely used grid-following(GFL)RESs,grid-forming(GFM)RESs exhibit the favorable characteristics of voltage sources.Therefore,the hybrid operation of GFL-/GFM-RESs holds great potential in voltage support and may help CF suppression.This paper first analyzes the impacts of RESs on the first and subsequent CFs,respectively.It reveals that GFM-RESs alleviate the deterioration of grid voltage induced by GFL-RESs,thereby suppressing the first CF.However,current fault ride-through controls of RESs cannot fulfill the reactive power dynamic demand during the CF recovery process and rarely help mitigate subsequent CFs.Moreover,the limited overcurrent capability of GFM-RES hinders its ability to ride through CF.Based on the mechanism analysis,a CF suppression strategy based on the hybrid GFL/GFM operation is proposed.The proposed strategy optimized the controls of RESs to fulfill reactive power dynamics and offer voltage support during the CF process.Case studies are undertaken on the studied system and the CIGRE benchmark,respectively.The simulation results confirm the effectiveness of the proposed strategy for suppressing CF.展开更多
Zn-I_(2) batteries have emerged as promising next-generation energy storage systems owing to their inherent safety,environmental compatibility,rapid reaction kinetics,and small voltage hysteresis.Nevertheless,two crit...Zn-I_(2) batteries have emerged as promising next-generation energy storage systems owing to their inherent safety,environmental compatibility,rapid reaction kinetics,and small voltage hysteresis.Nevertheless,two critical challenges,i.e.,zinc dendrite growth and polyiodide shuttle effect,severely impede their commercial viability.To conquer these limitations,this study develops a multifunctional separator fabricated from straw-derived carboxylated nanocellulose,with its negative charge density further reinforced by anionic polyacrylamide incorporation.This modification simultaneously improves the separator’s mechanical properties,ionic conductivity,and Zn^(2+)ion transfer number.Remarkably,despite its ultrathin 20μm profile,the engineered separator demonstrates exceptional dendrite suppression and parasitic reaction inhibition,enabling Zn//Zn symmetric cells to achieve impressive cycle life(>1800 h at 2 m A cm^(-2)/2 m Ah cm^(-2))while maintaining robust performance even at ultrahigh areal capacities(25 m Ah cm^(-2)).Additionally,the separator’s anionic characteristic effectively blocks polyiodide migration through electrostatic repulsion,yielding Zn-I_(2) batteries with outstanding rate capability(120.7 m Ah g^(-1)at 5 A g^(-1))and excellent cyclability(94.2%capacity retention after 10,000 cycles).And superior cycling stability can still be achieved under zinc-deficient condition and pouch cell configuration.This work establishes a new paradigm for designing high-performance zinc-based energy storage systems through rational separator engineering.展开更多
Fires and human casualties caused by single phase-to-ground faults in distribution networks are frequent.However,existing ground fault suppression methods are affected by ground fault resistance.Thus,an adaptive suppr...Fires and human casualties caused by single phase-to-ground faults in distribution networks are frequent.However,existing ground fault suppression methods are affected by ground fault resistance.Thus,an adaptive suppression method that seamlessly combines principles of current and voltage suppression is proposed,which has good adaptability to different ground fault resistance.Meanwhile,a multi-criteria ground fault suppression exit strategy matched to adaptive suppression method is proposed to avoid damage of device caused by power backflow,which provides the possibility for reliable and fast exit of the fault suppression device.Experimental results demonstrate effectiveness and advantages of the adaptive suppression method and its exit strategy.展开更多
Prelaunch rolling of maritime rockets threatens the reliability of launch in rough sea conditions.In order to suppress the prelaunch rolling,this study introduces advanced smart prediction designed especially for mari...Prelaunch rolling of maritime rockets threatens the reliability of launch in rough sea conditions.In order to suppress the prelaunch rolling,this study introduces advanced smart prediction designed especially for maritime rockets.The suggested approach introduces a hybrid model that combines random forest(RF)and Adaptive boosting(Ada Boost)methods to describe the coupling mechanism of factors affecting rocket rolling and to suppress the rolling.This combination improves forecast accuracy.Thereafter,the dimensionality reduced response surfaces are used to visually present the coupling between rocket rolling and influencing factors,which reveals the prelaunch rolling mechanism.When angle between the launch device and the ship's bow is within 80°-100°,the dynamic friction coefficient between adapters and guideways is 0.4,and the dynamic friction coefficient between the rocket and launchpad is within 0-0.15 or0.5-0.7,the prelaunch rolling of rocket during one motion cycle of the ship is less than 0.065°,originally 0.27°,reduced by 75.93%,effectively suppressing the prelaunch rolling.This study improves the prelaunch stability of maritime rockets in rough sea conditions and establishes a mapping relationship between the factors affecting rocket rolling and the structure of the sea launch system,guiding the optimization of future sea launch systems.展开更多
Optical coherence tomography(OCT),particularly Swept-Source OCT,is widely employed in medical diagnostics and industrial inspections owing to its high-resolution imaging capabilities.However,Swept-Source OCT 3D imagin...Optical coherence tomography(OCT),particularly Swept-Source OCT,is widely employed in medical diagnostics and industrial inspections owing to its high-resolution imaging capabilities.However,Swept-Source OCT 3D imaging often suffers from stripe artifacts caused by unstable light sources,system noise,and environmental interference,posing challenges to real-time processing of large-scale datasets.To address this issue,this study introduces a real-time reconstruction system that integrates stripe-artifact suppression and parallel computing using a graphics processing unit.This approach employs a frequency-domain filtering algorithm with adaptive anti-suppression parameters,dynamically adjusted through an image quality evaluation function and optimized using a convolutional neural network for complex frequency-domain feature learning.Additionally,a graphics processing unit integrated 3D reconstruction framework is developed,enhancing data processing throughput and real-time performance via a dual-queue decoupling mechanism.Experimental results demonstrate significant improvements in structural similarity(0.92),peak signal-to-noise ratio(31.62 dB),and stripe suppression ratio(15.73 dB)compared with existing methods.On the RTX 4090 platform,the proposed system achieved an end-to-end delay of 94.36 milliseconds,a frame rate of 10.3 frames per second,and a throughput of 121.5 million voxels per second,effectively suppressing artifacts while preserving image details and enhancing real-time 3D reconstruction performance.展开更多
Lithium-oxygen(Li-O2)batteries are perceived as a promising breakthrough in sustainable electrochemical energy storage,utilizing ambient air as an energy source,eliminating the need for costly cathode materials,and of...Lithium-oxygen(Li-O2)batteries are perceived as a promising breakthrough in sustainable electrochemical energy storage,utilizing ambient air as an energy source,eliminating the need for costly cathode materials,and offering the highest theoretical energy density(~3.5 k Wh kg^(-1))among discussed candidates.Contributing to the poor cycle life of currently reported Li-O_(2)cells is singlet oxygen(1O_(2))formation,inducing parasitic reactions,degrading key components,and severely deteriorating cell performance.Here,we harness the chirality-induced spin selectivity effect of chiral cobalt oxide nanosheets(Co_(3)O_(4)NSs)as cathode materials to suppress 1O_(2)in Li-O_(2)batteries for the first time.Operando photoluminescence spectroscopy reveals a 3.7-fold and 3.23-fold reduction in 1O_(2)during discharge and charge,respectively,compared to conventional carbon paperbased cells,consistent with differential electrochemical mass spectrometry results,which indicate a near-theoretical charge-to-O_(2)ratio(2.04 e-/O_(2)).Density functional theory calculations demonstrate that chirality induces a peak shift near the Fermi level,enhancing Co 3d-O 2p hybridization,stabilizing reaction intermediates,and lowering activation barriers for Li_(2)O_(2)formation and decomposition.These findings establish a new strategy for improving the stability and energy efficiency of sustainable Li-O_(2)batteries,abridging the current gap to commercialization.展开更多
The electrolyte additive,lithium nitrate(LiNO_(3)),is widely recognized for suppressing dendritic lithium growth in anode-free lithium metal batteries,yet its stabilizing effect is transient,and the mechanistic origin...The electrolyte additive,lithium nitrate(LiNO_(3)),is widely recognized for suppressing dendritic lithium growth in anode-free lithium metal batteries,yet its stabilizing effect is transient,and the mechanistic origin of this limitation has remained unresolved.Here,we uncover the origin of this behavior through a comprehensive analysis driven by artifact/damage-free direct cryogenic transmission electron microscopy,which enabled one of the most chemically specific and morphologically intuitive visualizations to date of intact solid-electrolyte interphases(SEIs)and lithium growth.Contrary to conventional interpretations centered on nitrogen-rich or single-component SEIs,we reveal that LiNO_(3) rapidly generates lithium hydroxide(LiOH)and lithium oxide(Li_(2)O)rich interphases,whose complementary functions—ionic transport through LiOH and mechanical robustness from Li_(2)O—synergistically suppress whisker nucleation and favor compact,particle-like growth.Over the extended plating,however,depletion of these species in combination with crystallographically favored orientations drives the particle-towhisker transition,explaining why the effectiveness of LiNO_(3) is inherently limited.This direct mechanistic visualization resolves a long-standing ambiguity regarding the transient efficacy of LiNO_(3) and reframes its function from a nitrogen-driven mechanism to a synergistic dual oxygen-interphase framework.Beyond mechanistic clarification,these findings establish that continuous regeneration of LiOH and Li_(2)O is essential for stable lithium deposition,offering a design principle for the development of durable electrolytes in high-performance anode-free lithium metal batteries.展开更多
As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness.To address thes...As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness.To address these challenges,we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA),which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror milling.This system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling process.Additionally,the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator,which alters the distance between magnets.This resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool interference.The frequency shift characteristics and vibration absorption performance are comprehensively investigated.Theoretical and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool,resulting in a vibration suppression rate of approximately 47.57%.Moreover,the roughness of the machined surface decreases by18.95%,significantly enhancing the surface quality.The results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.展开更多
The active sound absorption technique excels in mitigating low-frequency sound waves,yet it falls short when dealing with medium and high-frequency sound waves.To enhance the sound-absorbing effect of medium and high-...The active sound absorption technique excels in mitigating low-frequency sound waves,yet it falls short when dealing with medium and high-frequency sound waves.To enhance the sound-absorbing effect of medium and high-frequency sound waves,a novel semi-active sound absorption method has been introduced.This method modulates the surface impedance of a loudspeaker positioned behind the sound-absorbing material,thereby altering the sound absorption coefficient.The theoretical sound absorption coefficient is calculated using MATLAB and compared with the experimental one.Results show that the method can effectively modulates the absorption coefficient in response to varying incident sound wave frequencies,ensuring that it remains at its peak value.展开更多
The large amount of harmful particles in coal dust not only pollutes the production environment,affects the production efficiency and resource utilization of enterprises,but also poses a risk to human health.Effective...The large amount of harmful particles in coal dust not only pollutes the production environment,affects the production efficiency and resource utilization of enterprises,but also poses a risk to human health.Effectively controlling coal dust is of great significance to clean production.Water-based dust suppressants are extensively employed to mitigate coal dust.This paper provides a comprehensive review of the water-based dust suppression materials for coal dust control.Accord-ing to the difference of mechanism,the dust suppressants are divided into wetting type,hygroscopic coalescence type,cohesive agglomeration type,and composite type.The evaluation methods for dust suppressants key properties such as wettability,permeability,moisture absorption and water retention,and consolidation are summarized.The review results show that coal dust suppressants are no longer limited to a single dust suppression function.For example,it is necessary to develop multi-functional coal suppressants to meet the needs for synergistic suppression both coal dust and coal spon-taneous combustion.Driven by the concept of green,low-carbon and sustainable development,attention should be paid to the development of bio-based environmentally friendly coal dust suppressants.In addition,the evaluation method system for the key performance of water-based dust suppressants should also be improved,and further research is necessary.展开更多
A numerical simulation analysis is conducted to examine the unsteady hydrodynamic characteristics of vortex-induced vibration(VIV)and the suppression effect of helical strakes on VIV in subsea pipelines.The analysis u...A numerical simulation analysis is conducted to examine the unsteady hydrodynamic characteristics of vortex-induced vibration(VIV)and the suppression effect of helical strakes on VIV in subsea pipelines.The analysis uses the standard k−εturbulence model for 4.5-and 12.75-inch pipes,and its accuracy is verified by comparing the results with large-scale hydrodynamic experiments.These experiments are designed to evaluate the suppression efficiency of VIV with and without helical strakes,focusing on displacement and drag coefficients under different flow conditions.Furthermore,the influence of important geometric parameters of the helical strakes on drag coefficients and VIV suppression efficiency at different flow rates is compared and discussed.Numerical results agree well with experimental data for drag coefficient and vortex shedding frequency.Spring-pipe self-excited vibration experimental tests reveal that the installation of helical strakes substantially reduces the drag coefficient of VIV within a certain flow rate range,achieving suppression efficiencies exceeding 90%with strake heights larger than 0.15D.Notably,the optimized parameter combination of helical strakes,with a pitch of 15D,a fin height of 0.2D,and 45°edge slopes,maintains high suppression efficiency,thereby exhibiting superior performance.This study provides a valuable reference for the design and application of helical strakes and VIV suppression in subsea engineering.展开更多
The unavoidable dendrite growth and shuttle effect have long been stranglehold challenges limiting the safety and practicality of lithium-sulfur batteries.Herein,we propose a dual-action strategy to address the lithiu...The unavoidable dendrite growth and shuttle effect have long been stranglehold challenges limiting the safety and practicality of lithium-sulfur batteries.Herein,we propose a dual-action strategy to address the lithium dendrite issue in stages by constructing a multifunctional surface-negatively-charged nanodiamond layer with high ductility and robust puncture resistance on polypropylene (PP) separator.The uniformly loaded compact negative layer can not only significantly enhance electron transmission efficiency and promote uniform lithium deposition,but also reduce the formation of dendrite during early deposition stage.Most importantly,under the strong puncture stress encountered during the deterioration of lithium dendrite growth under limiting current,the high ductility and robust puncture resistance(145.88 MPa) of as-obtained nanodiamond layer can effectively prevent short circuits caused by unavoidable lithium dendrite.The Li||Li symmetrical cells assembled with nanodiamond layer modified PP demonstrated a stable cycle of over 1000 h at 2 mA cm^(-2)with a polarization voltage of only 29.3 mV.Additionally,the negative charged layer serves as a physical barrier blocking lithium polysulfide ions,effectively mitigating capacity attenuation.The improved cells achieved a capacity decay of only 0.042%per cycle after 700 cycles at 3 C,demonstrating effective suppression of dendrite growth and capacity attenuation,showing promising prospect.展开更多
Li metal is widely recognized as the desired anode for next-generation energy storage,Li metal batteries,due to its highest theoretical capacity and lowest potential.Nonetheless,it suffers from unstable electrochemica...Li metal is widely recognized as the desired anode for next-generation energy storage,Li metal batteries,due to its highest theoretical capacity and lowest potential.Nonetheless,it suffers from unstable electrochemical behaviors like dendrite growth and side reactions in practical application.Herein,we report a highly stable anode with collector,Li_(5)Mg@Cu,realized by the melting-rolling process.The Li_(5)Mg@Cu anode delivers ultrahigh cycle stability for 2000 and 1000 h at the current densities of 1 and 2 mA cm^(-2),respectively in symmetric cells.Meanwhile,the Li_(5)Mg@Cu|LFP cell exhibits a high-capacity retention of 91.8% for 1000 cycles and 78.8% for 2000 cycles at 1 C.Moreover,we investigate the suppression effects of Mg on the dendrite growth by studying the performance of Li_(x)Mg@Cu electrodes with different Mg contents(2.0-16.7 at%).The exchange current density,surface energy,Li^(+)diffusion coefficient,and chemical stability of Li_(x)Mg@Cu concretely reveal this improving suppression effect when Mg content becomes higher.In addition,a Mg-rich phase with“hollow brick”morphology forming in the high Mg content Li_(x)Mg@Cu guides the uniform deposition of Li.This study reveals the suppression effects of Mg on Li dendrites growth and offers a perspective for finding the optimal component of Li-Mg alloys.展开更多
A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the s...A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the spatial spectrum and the directions of arrival(DOA)of interferences to overcome the drawbacks associated with conventional adaptive beamforming(ABF)methods.The mainlobe interferences are identified by calculating the correlation coefficients between direction steering vectors(SVs)and rejected by the BMP pretreatment.Then,IAA is subsequently employed to reconstruct a sidelobe interference-plus-noise covariance matrix for the preferable ABF and residual interference suppression.Simulation results demonstrate the excellence of the proposed method over normal methods based on BMP and eigen-projection matrix perprocessing(EMP)under both uncorrelated and coherent circumstances.展开更多
High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking...High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking suppression mechanism and phase formation in these composites are not clarified.In this work,microstructure evolution and mechanical performance of the LPBF-fabricated Ti/Ce co-modified 2195 are investigated to reveal their cracking suppression and strengthening mechanisms.The results show that apparent grain refinement of the composites is ascribed to high supercooling from rapid formation of constitutional supercooling zone in front of solid–liquid interfaces by high-Q-value Ti solute,and heterogeneous nucleation of in situ formed Al3Ti and Al11Ce3precipitates.Their synergistic interactions promote formation of fine equiaxed grains and thus inhibit crack initiation.The composites exhibit high microhardness of 100±5HV0.2,nano-hardness of 1.6±0.1 GPa and elastic modulus of 97±3 GPa,where the elastic modulus increases by 27%and 31%compared to those of LPBF-processed and conventionally manufactured 2195 alloys,respectively.A tensile strength of 336 MPa and an elongation of 3%are obtained from in-situ synchrotron X-ray diffraction measurement.The improved properties are derived from grain refinement and Orowan strengthening.Based on the optimal processing parameter and composition,a bracket component filled with lattice structures is designed and manufactured with good manufacturing quality and processing accuracy.展开更多
In recent years,gait-based emotion recognition has been widely applied in the field of computer vision.However,existing gait emotion recognition methods typically rely on complete human skeleton data,and their accurac...In recent years,gait-based emotion recognition has been widely applied in the field of computer vision.However,existing gait emotion recognition methods typically rely on complete human skeleton data,and their accuracy significantly declines when the data is occluded.To enhance the accuracy of gait emotion recognition under occlusion,this paper proposes a Multi-scale Suppression Graph ConvolutionalNetwork(MS-GCN).TheMS-GCN consists of three main components:Joint Interpolation Module(JI Moudle),Multi-scale Temporal Convolution Network(MS-TCN),and Suppression Graph Convolutional Network(SGCN).The JI Module completes the spatially occluded skeletal joints using the(K-Nearest Neighbors)KNN interpolation method.The MS-TCN employs convolutional kernels of various sizes to comprehensively capture the emotional information embedded in the gait,compensating for the temporal occlusion of gait information.The SGCN extracts more non-prominent human gait features by suppressing the extraction of key body part features,thereby reducing the negative impact of occlusion on emotion recognition results.The proposed method is evaluated on two comprehensive datasets:Emotion-Gait,containing 4227 real gaits from sources like BML,ICT-Pollick,and ELMD,and 1000 synthetic gaits generated using STEP-Gen technology,and ELMB,consisting of 3924 gaits,with 1835 labeled with emotions such as“Happy,”“Sad,”“Angry,”and“Neutral.”On the standard datasets Emotion-Gait and ELMB,the proposed method achieved accuracies of 0.900 and 0.896,respectively,attaining performance comparable to other state-ofthe-artmethods.Furthermore,on occlusion datasets,the proposedmethod significantly mitigates the performance degradation caused by occlusion compared to other methods,the accuracy is significantly higher than that of other methods.展开更多
Nonperiodic interrupted sampling repeater jamming(ISRJ)against inverse synthetic aperture radar(ISAR)can obtain two-dimensional blanket jamming performance by joint fast and slow time domain interrupted modulation,whi...Nonperiodic interrupted sampling repeater jamming(ISRJ)against inverse synthetic aperture radar(ISAR)can obtain two-dimensional blanket jamming performance by joint fast and slow time domain interrupted modulation,which is obviously dif-ferent from the conventional multi-false-target deception jam-ming.In this paper,a suppression method against this kind of novel jamming is proposed based on inter-pulse energy function and compressed sensing theory.By utilizing the discontinuous property of the jamming in slow time domain,the unjammed pulse is separated using the intra-pulse energy function diffe-rence.Based on this,the two-dimensional orthogonal matching pursuit(2D-OMP)algorithm is proposed.Further,it is proposed to reconstruct the ISAR image with the obtained unjammed pulse sequence.The validity of the proposed method is demon-strated via the Yake-42 plane data simulations.展开更多
BACKGROUND To prevent mother to child transmission(MTCT)of human immunodeficiency virus(HIV),sustained maternal viral load suppression(VLS)and early HIV testing among HIV exposed infants(HEI)is critical.AIM To investi...BACKGROUND To prevent mother to child transmission(MTCT)of human immunodeficiency virus(HIV),sustained maternal viral load suppression(VLS)and early HIV testing among HIV exposed infants(HEI)is critical.AIM To investigate maternal viral load results and infant HIV testing uptake at 6-weeks,and 9-months and 18-months in Rwanda.METHODS Between 2015 and 2022,VLS(<200 copies/mL)was measured among pregnant women living with HIV(WLHIV)from 38-healthcare facilities.Viral loads(VL)were measured at 6-months,12-months and 24-months,respectively.For maternal VL,the unit of analysis was visit-pair,and the pairs were created to define those with VL<200 copies/mL at two consecutive visits as having sustained VLS,persistent viremia(VL≥200 copies/mL at two consecutive visits),viral rebound(VL<200 copies/mL at prior visit only)and newly suppressed(VL<200 copies/mL at subsequent visit only).HEI were considered to have persistent HIV testing if they had all three HIV tests.Poisson regression models with generalized estimating equations were used to estimate the adjusted incidence rate ratio(aIRR)and 95%CI for factors associated with sustained VLS and persistent HIV testing.RESULTS A total of 1145 mother-infant pairs were analyzed.Infant HIV testing uptake at 6-weeks,9-months and 18-months was 1145(100.0%),1089(95.1%),1006(87.9%)respectively.Nine hundred ninety-nine HEI(87.3%)tested for HIV persistently.At 18-months,the incidence of HIV among HEI was 8(0.7%).Of 1145 mothers,1076(94.0%)had≥2 VL results making a total of 2010 visit-pairs(142-single;934-double visit-pairs).The incidence rate of sustained VLS,persistent viremia,viral rebound and new suppression were 91.0%,1.3%,3.6%and 4.0%respectively.Maternal disclosure of HIV status(aIRR=1.08,95%CI:1.02-1.14)was associated with increased likelihood of sustained VLS.Having peer support(aIRR=1.0595%CI:1.01-1.10)was associated with persistent HIV testing among HEI.CONCLUSION Sustained VLS is high among pregnant WLHIV in Rwanda.The low incidence of HIV among HEI may be attributed to high VLS levels.Targeted interventions,including enhanced HIV disclosure and peer support,are crucial for improving sustained VLS and increasing infant HIV testing uptake to reduce MTCT.展开更多
BACKGROUND Sustained viral load(VL)suppression is an important indicator of successful treatment among people living with human immunodeficiency virus(HIV).AIM To assess trends of different VL outcomes before and afte...BACKGROUND Sustained viral load(VL)suppression is an important indicator of successful treatment among people living with human immunodeficiency virus(HIV).AIM To assess trends of different VL outcomes before and after adoption of the Treat All policy among people living with HIV in Rwanda.METHODS Between 2014 and 2017,VL suppression[VL suppression(VLS)<200 copies/mL]was measured among people living with HIV from 28 healthcare facilities in Rwanda.Participant VL was measured at 6 months,18 months,and 30 months.The unit of analysis was visit-pair,with subjects across four visit-pair categories:(1)Sustained VL suppression(VL<200 copies/mL at two consecutive visits);(2)Persistent viremia(VL≥200 copies/mL at two consecutive visits);(3)Viral rebound(VL<200 copies/mL at prior visit only);and(4)Newly suppressed(VL<200 copies/mL at subsequent visit only).Poisson regression models with generalized estimating equations were used to estimate adjusted incidence risk ratio(aIRR)and 95%confidence intervals(CIs)for factors associated with sustained VLS.To handle missing data,multiple imputations was performed.RESULTS A total of 634 participants contributed 973 visit-pairs(295 single pairs and 339 double pairs).The median age was 37 years(interquartile range:32-43 years).The incidence rates of sustained VLS,persistent viremia,viral rebound,and new suppression were 85.2%,4.3%,4.6%,and 5.7%,respectively.Young individuals aged 18-24 years had higher incidence of viral rebound compared to those 25 years or older(14.8%vs 4.3%;P=0.011).Of the visit-pairs that had sustained VLS during the first two visits(49.8%;n=485),56.7%exhibited sustained VLS throughout follow-up.Compared to having no education,having at least primary education was associated with an increased likelihood of sustained VLS(aIRR=1.09;95%CI:1.01-1.17).Those who presented with advanced HIV disease at baseline had a 12%reduced likelihood of sustained VLS(aIRR=0.88;95%CI:0.79-0.99).Achieving sustained VLS did not differ before or after adoption of the Treat All policy.When the analysis was repeated on imputed datasets,similar results were found.CONCLUSION Although most people living with HIV have sustained VLS in Rwanda,individuals without formal education,those presenting with advanced HIV,and younger individuals were lagging on multiple outcomes.Interventions tailored to these individuals would improve treatment outcomes to achieve epidemic control.展开更多
文摘Noise interference critically impairs the stability and data accuracy of sensing systems.However,current suppression strategies fail to concurrently mitigate intrinsic system noise and extrinsic environmental noise.This study introduces a composite denoising approach to address this challenge.This method is based on the ameliorated ellipse fitting algorithm(AEFA)and adaptive successive variational mode decomposition(ASVMD).This algorithm employs AEFA to eliminate system noise tightly coupled with direct-current and alternating-current components in the interference signal,thereby obtaining a phase signal containing only environmental noise.The ASVMD technique adaptively extracts environmental noise components predominantly present in the phase signal.To achieve optimal decomposition results automatically,the permutation entropy criterion is employed to refine decomposition parameters.The correlation coefficient is utilized to differentiate effective components from noise components in the decomposition results.Experimental results indicate that the combined AEFA and ASVMD algorithm effectively suppresses both system and environmental noises.When applied to 50 Hz vibration signal processing,the proposed approach achieves a noise reduction of 17.81 dB and a phase resolution of 35.14μrad/√Hz.Given the excellent performance of the noise suppression,the proposed approach holds great application potential in high-performance interferometric sensing systems.
基金supported by the National Natural Science Foundation of China under Grant 52225704 and Grant U23B20120.
文摘With the integration of large-scale renewable energy sources(RESs),the line commutated converter(LCC)based high-voltage direct-current(HVDC)inverter side suffers from degraded grid strength and escalating commutation failure(CF)risks.In comparison with the widely used grid-following(GFL)RESs,grid-forming(GFM)RESs exhibit the favorable characteristics of voltage sources.Therefore,the hybrid operation of GFL-/GFM-RESs holds great potential in voltage support and may help CF suppression.This paper first analyzes the impacts of RESs on the first and subsequent CFs,respectively.It reveals that GFM-RESs alleviate the deterioration of grid voltage induced by GFL-RESs,thereby suppressing the first CF.However,current fault ride-through controls of RESs cannot fulfill the reactive power dynamic demand during the CF recovery process and rarely help mitigate subsequent CFs.Moreover,the limited overcurrent capability of GFM-RES hinders its ability to ride through CF.Based on the mechanism analysis,a CF suppression strategy based on the hybrid GFL/GFM operation is proposed.The proposed strategy optimized the controls of RESs to fulfill reactive power dynamics and offer voltage support during the CF process.Case studies are undertaken on the studied system and the CIGRE benchmark,respectively.The simulation results confirm the effectiveness of the proposed strategy for suppressing CF.
基金the financial support from the Natural Science Foundation of Jiangsu Province(BK20231292)the Jiangsu Agricultural Science and Technology Innovation Fund(CX(24)3091)+6 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX25_1429)the National Key R&D Program of China(2024YFE0109200)the Fundamental Research Funds for the Central Universities(No.2024300440)Guangdong Basic and Applied Basic Research Foundation(2025A1515011098)the National Natural Science Foundation of China(12464032)the Natural Science Foundation of Jiangxi Province(20232BAB201032)Ji'an Science and Technology Plan Project(2024H-100301)。
文摘Zn-I_(2) batteries have emerged as promising next-generation energy storage systems owing to their inherent safety,environmental compatibility,rapid reaction kinetics,and small voltage hysteresis.Nevertheless,two critical challenges,i.e.,zinc dendrite growth and polyiodide shuttle effect,severely impede their commercial viability.To conquer these limitations,this study develops a multifunctional separator fabricated from straw-derived carboxylated nanocellulose,with its negative charge density further reinforced by anionic polyacrylamide incorporation.This modification simultaneously improves the separator’s mechanical properties,ionic conductivity,and Zn^(2+)ion transfer number.Remarkably,despite its ultrathin 20μm profile,the engineered separator demonstrates exceptional dendrite suppression and parasitic reaction inhibition,enabling Zn//Zn symmetric cells to achieve impressive cycle life(>1800 h at 2 m A cm^(-2)/2 m Ah cm^(-2))while maintaining robust performance even at ultrahigh areal capacities(25 m Ah cm^(-2)).Additionally,the separator’s anionic characteristic effectively blocks polyiodide migration through electrostatic repulsion,yielding Zn-I_(2) batteries with outstanding rate capability(120.7 m Ah g^(-1)at 5 A g^(-1))and excellent cyclability(94.2%capacity retention after 10,000 cycles).And superior cycling stability can still be achieved under zinc-deficient condition and pouch cell configuration.This work establishes a new paradigm for designing high-performance zinc-based energy storage systems through rational separator engineering.
基金supported by the National Natural Science Foundation of China(51677030).
文摘Fires and human casualties caused by single phase-to-ground faults in distribution networks are frequent.However,existing ground fault suppression methods are affected by ground fault resistance.Thus,an adaptive suppression method that seamlessly combines principles of current and voltage suppression is proposed,which has good adaptability to different ground fault resistance.Meanwhile,a multi-criteria ground fault suppression exit strategy matched to adaptive suppression method is proposed to avoid damage of device caused by power backflow,which provides the possibility for reliable and fast exit of the fault suppression device.Experimental results demonstrate effectiveness and advantages of the adaptive suppression method and its exit strategy.
文摘Prelaunch rolling of maritime rockets threatens the reliability of launch in rough sea conditions.In order to suppress the prelaunch rolling,this study introduces advanced smart prediction designed especially for maritime rockets.The suggested approach introduces a hybrid model that combines random forest(RF)and Adaptive boosting(Ada Boost)methods to describe the coupling mechanism of factors affecting rocket rolling and to suppress the rolling.This combination improves forecast accuracy.Thereafter,the dimensionality reduced response surfaces are used to visually present the coupling between rocket rolling and influencing factors,which reveals the prelaunch rolling mechanism.When angle between the launch device and the ship's bow is within 80°-100°,the dynamic friction coefficient between adapters and guideways is 0.4,and the dynamic friction coefficient between the rocket and launchpad is within 0-0.15 or0.5-0.7,the prelaunch rolling of rocket during one motion cycle of the ship is less than 0.065°,originally 0.27°,reduced by 75.93%,effectively suppressing the prelaunch rolling.This study improves the prelaunch stability of maritime rockets in rough sea conditions and establishes a mapping relationship between the factors affecting rocket rolling and the structure of the sea launch system,guiding the optimization of future sea launch systems.
文摘Optical coherence tomography(OCT),particularly Swept-Source OCT,is widely employed in medical diagnostics and industrial inspections owing to its high-resolution imaging capabilities.However,Swept-Source OCT 3D imaging often suffers from stripe artifacts caused by unstable light sources,system noise,and environmental interference,posing challenges to real-time processing of large-scale datasets.To address this issue,this study introduces a real-time reconstruction system that integrates stripe-artifact suppression and parallel computing using a graphics processing unit.This approach employs a frequency-domain filtering algorithm with adaptive anti-suppression parameters,dynamically adjusted through an image quality evaluation function and optimized using a convolutional neural network for complex frequency-domain feature learning.Additionally,a graphics processing unit integrated 3D reconstruction framework is developed,enhancing data processing throughput and real-time performance via a dual-queue decoupling mechanism.Experimental results demonstrate significant improvements in structural similarity(0.92),peak signal-to-noise ratio(31.62 dB),and stripe suppression ratio(15.73 dB)compared with existing methods.On the RTX 4090 platform,the proposed system achieved an end-to-end delay of 94.36 milliseconds,a frame rate of 10.3 frames per second,and a throughput of 121.5 million voxels per second,effectively suppressing artifacts while preserving image details and enhancing real-time 3D reconstruction performance.
基金supported by Basic Science Research Program(Priority Research Institute)through the NRF of Korea funded by the Ministry of Education(2021R1A6A1A10039823)by the Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Education(2020R1A6C101B194)。
文摘Lithium-oxygen(Li-O2)batteries are perceived as a promising breakthrough in sustainable electrochemical energy storage,utilizing ambient air as an energy source,eliminating the need for costly cathode materials,and offering the highest theoretical energy density(~3.5 k Wh kg^(-1))among discussed candidates.Contributing to the poor cycle life of currently reported Li-O_(2)cells is singlet oxygen(1O_(2))formation,inducing parasitic reactions,degrading key components,and severely deteriorating cell performance.Here,we harness the chirality-induced spin selectivity effect of chiral cobalt oxide nanosheets(Co_(3)O_(4)NSs)as cathode materials to suppress 1O_(2)in Li-O_(2)batteries for the first time.Operando photoluminescence spectroscopy reveals a 3.7-fold and 3.23-fold reduction in 1O_(2)during discharge and charge,respectively,compared to conventional carbon paperbased cells,consistent with differential electrochemical mass spectrometry results,which indicate a near-theoretical charge-to-O_(2)ratio(2.04 e-/O_(2)).Density functional theory calculations demonstrate that chirality induces a peak shift near the Fermi level,enhancing Co 3d-O 2p hybridization,stabilizing reaction intermediates,and lowering activation barriers for Li_(2)O_(2)formation and decomposition.These findings establish a new strategy for improving the stability and energy efficiency of sustainable Li-O_(2)batteries,abridging the current gap to commercialization.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2024-00406724(50%)RS-2023-00222411,RS-2025-24533073)+2 种基金the Korea Basic Science Institute(National research Facilities and Equipment Center)grant funded by the Korea government(MOE)(RS-2024-00436346)the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea government(MOTIE)(RS-2024-00417730,HRD Program for Industrial Innovation)the research fund of Hanyang University(HY-202100000003295)。
文摘The electrolyte additive,lithium nitrate(LiNO_(3)),is widely recognized for suppressing dendritic lithium growth in anode-free lithium metal batteries,yet its stabilizing effect is transient,and the mechanistic origin of this limitation has remained unresolved.Here,we uncover the origin of this behavior through a comprehensive analysis driven by artifact/damage-free direct cryogenic transmission electron microscopy,which enabled one of the most chemically specific and morphologically intuitive visualizations to date of intact solid-electrolyte interphases(SEIs)and lithium growth.Contrary to conventional interpretations centered on nitrogen-rich or single-component SEIs,we reveal that LiNO_(3) rapidly generates lithium hydroxide(LiOH)and lithium oxide(Li_(2)O)rich interphases,whose complementary functions—ionic transport through LiOH and mechanical robustness from Li_(2)O—synergistically suppress whisker nucleation and favor compact,particle-like growth.Over the extended plating,however,depletion of these species in combination with crystallographically favored orientations drives the particle-towhisker transition,explaining why the effectiveness of LiNO_(3) is inherently limited.This direct mechanistic visualization resolves a long-standing ambiguity regarding the transient efficacy of LiNO_(3) and reframes its function from a nitrogen-driven mechanism to a synergistic dual oxygen-interphase framework.Beyond mechanistic clarification,these findings establish that continuous regeneration of LiOH and Li_(2)O is essential for stable lithium deposition,offering a design principle for the development of durable electrolytes in high-performance anode-free lithium metal batteries.
基金Project supported by the National Natural Science Foundation of China(Nos.12172248,12021002,12302022,and 12132010)the Tianjin Research Program of Application Foundation and Advanced Technology of China(No.22JCQNJC00780)IoT Standards and Application Key Laboratory of the Ministry of Industry and Information Technology of China(No.202306)。
文摘As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness.To address these challenges,we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA),which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror milling.This system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling process.Additionally,the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator,which alters the distance between magnets.This resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool interference.The frequency shift characteristics and vibration absorption performance are comprehensively investigated.Theoretical and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool,resulting in a vibration suppression rate of approximately 47.57%.Moreover,the roughness of the machined surface decreases by18.95%,significantly enhancing the surface quality.The results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.
基金National Natural Science Foundation of China(No.51705545)。
文摘The active sound absorption technique excels in mitigating low-frequency sound waves,yet it falls short when dealing with medium and high-frequency sound waves.To enhance the sound-absorbing effect of medium and high-frequency sound waves,a novel semi-active sound absorption method has been introduced.This method modulates the surface impedance of a loudspeaker positioned behind the sound-absorbing material,thereby altering the sound absorption coefficient.The theoretical sound absorption coefficient is calculated using MATLAB and compared with the experimental one.Results show that the method can effectively modulates the absorption coefficient in response to varying incident sound wave frequencies,ensuring that it remains at its peak value.
基金supported by the National Natural Science Foundation of China(52474226,52322404)Basic scientific research projects in higher education institutions of Liaoning Province(JYTZD2023079)。
文摘The large amount of harmful particles in coal dust not only pollutes the production environment,affects the production efficiency and resource utilization of enterprises,but also poses a risk to human health.Effectively controlling coal dust is of great significance to clean production.Water-based dust suppressants are extensively employed to mitigate coal dust.This paper provides a comprehensive review of the water-based dust suppression materials for coal dust control.Accord-ing to the difference of mechanism,the dust suppressants are divided into wetting type,hygroscopic coalescence type,cohesive agglomeration type,and composite type.The evaluation methods for dust suppressants key properties such as wettability,permeability,moisture absorption and water retention,and consolidation are summarized.The review results show that coal dust suppressants are no longer limited to a single dust suppression function.For example,it is necessary to develop multi-functional coal suppressants to meet the needs for synergistic suppression both coal dust and coal spon-taneous combustion.Driven by the concept of green,low-carbon and sustainable development,attention should be paid to the development of bio-based environmentally friendly coal dust suppressants.In addition,the evaluation method system for the key performance of water-based dust suppressants should also be improved,and further research is necessary.
基金Supported by the National Natural Science Foundation of China (Grant No. 52222111)the National Science and Technology Major Project of China “Key Technologies and Equipment for Deepwater Dry Oil and Gas Production and Processing Platforms”(No. 2024ZD1403300)+1 种基金Subproject 5 “Research on Safety Risk Assessment Technology System for Deepwater Dry Oil and Gas Production and Processing Platforms”(No. 2024ZD1403305)the China Scholarship Council (202306440019)。
文摘A numerical simulation analysis is conducted to examine the unsteady hydrodynamic characteristics of vortex-induced vibration(VIV)and the suppression effect of helical strakes on VIV in subsea pipelines.The analysis uses the standard k−εturbulence model for 4.5-and 12.75-inch pipes,and its accuracy is verified by comparing the results with large-scale hydrodynamic experiments.These experiments are designed to evaluate the suppression efficiency of VIV with and without helical strakes,focusing on displacement and drag coefficients under different flow conditions.Furthermore,the influence of important geometric parameters of the helical strakes on drag coefficients and VIV suppression efficiency at different flow rates is compared and discussed.Numerical results agree well with experimental data for drag coefficient and vortex shedding frequency.Spring-pipe self-excited vibration experimental tests reveal that the installation of helical strakes substantially reduces the drag coefficient of VIV within a certain flow rate range,achieving suppression efficiencies exceeding 90%with strake heights larger than 0.15D.Notably,the optimized parameter combination of helical strakes,with a pitch of 15D,a fin height of 0.2D,and 45°edge slopes,maintains high suppression efficiency,thereby exhibiting superior performance.This study provides a valuable reference for the design and application of helical strakes and VIV suppression in subsea engineering.
基金National Natural Science Foundation of China (Grant 52372083, 52173255)Opening Project of the Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials (JSKC24025)+1 种基金Special Funds for the Trans-formation of Scientific and Technological Achievements in Jiangsu Province(BA2023003)Collaborative Innovation Center for Advanced Micro/nanomaterials and Equipment (Co-constructed by Jiangsu Province and Ministry of Education)。
文摘The unavoidable dendrite growth and shuttle effect have long been stranglehold challenges limiting the safety and practicality of lithium-sulfur batteries.Herein,we propose a dual-action strategy to address the lithium dendrite issue in stages by constructing a multifunctional surface-negatively-charged nanodiamond layer with high ductility and robust puncture resistance on polypropylene (PP) separator.The uniformly loaded compact negative layer can not only significantly enhance electron transmission efficiency and promote uniform lithium deposition,but also reduce the formation of dendrite during early deposition stage.Most importantly,under the strong puncture stress encountered during the deterioration of lithium dendrite growth under limiting current,the high ductility and robust puncture resistance(145.88 MPa) of as-obtained nanodiamond layer can effectively prevent short circuits caused by unavoidable lithium dendrite.The Li||Li symmetrical cells assembled with nanodiamond layer modified PP demonstrated a stable cycle of over 1000 h at 2 mA cm^(-2)with a polarization voltage of only 29.3 mV.Additionally,the negative charged layer serves as a physical barrier blocking lithium polysulfide ions,effectively mitigating capacity attenuation.The improved cells achieved a capacity decay of only 0.042%per cycle after 700 cycles at 3 C,demonstrating effective suppression of dendrite growth and capacity attenuation,showing promising prospect.
基金supported by the Qingdao Jiuhuanxinyue New Energy Technology Co.,Ltd.the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021B1515120071)+2 种基金the 21C Innovation Laboratory,Contemporary Amperex Technology Ltd.(Grant No.21C-OP-202112)the financial support from the Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515011873)the Shenzhen Science and Technology Program(Grant No.JCYJ20220531095212027).
文摘Li metal is widely recognized as the desired anode for next-generation energy storage,Li metal batteries,due to its highest theoretical capacity and lowest potential.Nonetheless,it suffers from unstable electrochemical behaviors like dendrite growth and side reactions in practical application.Herein,we report a highly stable anode with collector,Li_(5)Mg@Cu,realized by the melting-rolling process.The Li_(5)Mg@Cu anode delivers ultrahigh cycle stability for 2000 and 1000 h at the current densities of 1 and 2 mA cm^(-2),respectively in symmetric cells.Meanwhile,the Li_(5)Mg@Cu|LFP cell exhibits a high-capacity retention of 91.8% for 1000 cycles and 78.8% for 2000 cycles at 1 C.Moreover,we investigate the suppression effects of Mg on the dendrite growth by studying the performance of Li_(x)Mg@Cu electrodes with different Mg contents(2.0-16.7 at%).The exchange current density,surface energy,Li^(+)diffusion coefficient,and chemical stability of Li_(x)Mg@Cu concretely reveal this improving suppression effect when Mg content becomes higher.In addition,a Mg-rich phase with“hollow brick”morphology forming in the high Mg content Li_(x)Mg@Cu guides the uniform deposition of Li.This study reveals the suppression effects of Mg on Li dendrites growth and offers a perspective for finding the optimal component of Li-Mg alloys.
基金The National Natural Science Foundation of China(No.U19B2031).
文摘A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the spatial spectrum and the directions of arrival(DOA)of interferences to overcome the drawbacks associated with conventional adaptive beamforming(ABF)methods.The mainlobe interferences are identified by calculating the correlation coefficients between direction steering vectors(SVs)and rejected by the BMP pretreatment.Then,IAA is subsequently employed to reconstruct a sidelobe interference-plus-noise covariance matrix for the preferable ABF and residual interference suppression.Simulation results demonstrate the excellence of the proposed method over normal methods based on BMP and eigen-projection matrix perprocessing(EMP)under both uncorrelated and coherent circumstances.
基金supported by the National Natural Science Foundation of China(Nos.52205382,52225503)National Key Research and Development Program(No.2023YFB4603300)+3 种基金Key Research and Development Program of Jiangsu Province(Nos.BE2022069,BZ2024019)National Natural Science Foundation of China for Creative Research Groups(No.51921003)International Joint Laboratory of Sustainable Manufacturing,Ministry of Education and the Fundamental Research Funds for the Central Universities(NG2024014)Postgraduate Research&Practice Innovation Program of NUAA(xcxjh20230616)。
文摘High cracking susceptibility of Al-Li alloys with Ti/Ce B6addition is thoroughly suppressed in laser powder bed fusion(LPBF)processing of Ti/Ce co-modified 2195 alloys at relatively high scan speeds,while the cracking suppression mechanism and phase formation in these composites are not clarified.In this work,microstructure evolution and mechanical performance of the LPBF-fabricated Ti/Ce co-modified 2195 are investigated to reveal their cracking suppression and strengthening mechanisms.The results show that apparent grain refinement of the composites is ascribed to high supercooling from rapid formation of constitutional supercooling zone in front of solid–liquid interfaces by high-Q-value Ti solute,and heterogeneous nucleation of in situ formed Al3Ti and Al11Ce3precipitates.Their synergistic interactions promote formation of fine equiaxed grains and thus inhibit crack initiation.The composites exhibit high microhardness of 100±5HV0.2,nano-hardness of 1.6±0.1 GPa and elastic modulus of 97±3 GPa,where the elastic modulus increases by 27%and 31%compared to those of LPBF-processed and conventionally manufactured 2195 alloys,respectively.A tensile strength of 336 MPa and an elongation of 3%are obtained from in-situ synchrotron X-ray diffraction measurement.The improved properties are derived from grain refinement and Orowan strengthening.Based on the optimal processing parameter and composition,a bracket component filled with lattice structures is designed and manufactured with good manufacturing quality and processing accuracy.
基金supported by the National Natural Science Foundation of China(62272049,62236006,62172045)the Key Projects of Beijing Union University(ZKZD202301).
文摘In recent years,gait-based emotion recognition has been widely applied in the field of computer vision.However,existing gait emotion recognition methods typically rely on complete human skeleton data,and their accuracy significantly declines when the data is occluded.To enhance the accuracy of gait emotion recognition under occlusion,this paper proposes a Multi-scale Suppression Graph ConvolutionalNetwork(MS-GCN).TheMS-GCN consists of three main components:Joint Interpolation Module(JI Moudle),Multi-scale Temporal Convolution Network(MS-TCN),and Suppression Graph Convolutional Network(SGCN).The JI Module completes the spatially occluded skeletal joints using the(K-Nearest Neighbors)KNN interpolation method.The MS-TCN employs convolutional kernels of various sizes to comprehensively capture the emotional information embedded in the gait,compensating for the temporal occlusion of gait information.The SGCN extracts more non-prominent human gait features by suppressing the extraction of key body part features,thereby reducing the negative impact of occlusion on emotion recognition results.The proposed method is evaluated on two comprehensive datasets:Emotion-Gait,containing 4227 real gaits from sources like BML,ICT-Pollick,and ELMD,and 1000 synthetic gaits generated using STEP-Gen technology,and ELMB,consisting of 3924 gaits,with 1835 labeled with emotions such as“Happy,”“Sad,”“Angry,”and“Neutral.”On the standard datasets Emotion-Gait and ELMB,the proposed method achieved accuracies of 0.900 and 0.896,respectively,attaining performance comparable to other state-ofthe-artmethods.Furthermore,on occlusion datasets,the proposedmethod significantly mitigates the performance degradation caused by occlusion compared to other methods,the accuracy is significantly higher than that of other methods.
基金supported by the National Natural Science Foundation of China(62001481,61890542,62071475)the Natural Science Foundation of Hunan Province(2022JJ40561)the Research Program of National University of Defense Technology(ZK22-46).
文摘Nonperiodic interrupted sampling repeater jamming(ISRJ)against inverse synthetic aperture radar(ISAR)can obtain two-dimensional blanket jamming performance by joint fast and slow time domain interrupted modulation,which is obviously dif-ferent from the conventional multi-false-target deception jam-ming.In this paper,a suppression method against this kind of novel jamming is proposed based on inter-pulse energy function and compressed sensing theory.By utilizing the discontinuous property of the jamming in slow time domain,the unjammed pulse is separated using the intra-pulse energy function diffe-rence.Based on this,the two-dimensional orthogonal matching pursuit(2D-OMP)algorithm is proposed.Further,it is proposed to reconstruct the ISAR image with the obtained unjammed pulse sequence.The validity of the proposed method is demon-strated via the Yake-42 plane data simulations.
文摘BACKGROUND To prevent mother to child transmission(MTCT)of human immunodeficiency virus(HIV),sustained maternal viral load suppression(VLS)and early HIV testing among HIV exposed infants(HEI)is critical.AIM To investigate maternal viral load results and infant HIV testing uptake at 6-weeks,and 9-months and 18-months in Rwanda.METHODS Between 2015 and 2022,VLS(<200 copies/mL)was measured among pregnant women living with HIV(WLHIV)from 38-healthcare facilities.Viral loads(VL)were measured at 6-months,12-months and 24-months,respectively.For maternal VL,the unit of analysis was visit-pair,and the pairs were created to define those with VL<200 copies/mL at two consecutive visits as having sustained VLS,persistent viremia(VL≥200 copies/mL at two consecutive visits),viral rebound(VL<200 copies/mL at prior visit only)and newly suppressed(VL<200 copies/mL at subsequent visit only).HEI were considered to have persistent HIV testing if they had all three HIV tests.Poisson regression models with generalized estimating equations were used to estimate the adjusted incidence rate ratio(aIRR)and 95%CI for factors associated with sustained VLS and persistent HIV testing.RESULTS A total of 1145 mother-infant pairs were analyzed.Infant HIV testing uptake at 6-weeks,9-months and 18-months was 1145(100.0%),1089(95.1%),1006(87.9%)respectively.Nine hundred ninety-nine HEI(87.3%)tested for HIV persistently.At 18-months,the incidence of HIV among HEI was 8(0.7%).Of 1145 mothers,1076(94.0%)had≥2 VL results making a total of 2010 visit-pairs(142-single;934-double visit-pairs).The incidence rate of sustained VLS,persistent viremia,viral rebound and new suppression were 91.0%,1.3%,3.6%and 4.0%respectively.Maternal disclosure of HIV status(aIRR=1.08,95%CI:1.02-1.14)was associated with increased likelihood of sustained VLS.Having peer support(aIRR=1.0595%CI:1.01-1.10)was associated with persistent HIV testing among HEI.CONCLUSION Sustained VLS is high among pregnant WLHIV in Rwanda.The low incidence of HIV among HEI may be attributed to high VLS levels.Targeted interventions,including enhanced HIV disclosure and peer support,are crucial for improving sustained VLS and increasing infant HIV testing uptake to reduce MTCT.
文摘BACKGROUND Sustained viral load(VL)suppression is an important indicator of successful treatment among people living with human immunodeficiency virus(HIV).AIM To assess trends of different VL outcomes before and after adoption of the Treat All policy among people living with HIV in Rwanda.METHODS Between 2014 and 2017,VL suppression[VL suppression(VLS)<200 copies/mL]was measured among people living with HIV from 28 healthcare facilities in Rwanda.Participant VL was measured at 6 months,18 months,and 30 months.The unit of analysis was visit-pair,with subjects across four visit-pair categories:(1)Sustained VL suppression(VL<200 copies/mL at two consecutive visits);(2)Persistent viremia(VL≥200 copies/mL at two consecutive visits);(3)Viral rebound(VL<200 copies/mL at prior visit only);and(4)Newly suppressed(VL<200 copies/mL at subsequent visit only).Poisson regression models with generalized estimating equations were used to estimate adjusted incidence risk ratio(aIRR)and 95%confidence intervals(CIs)for factors associated with sustained VLS.To handle missing data,multiple imputations was performed.RESULTS A total of 634 participants contributed 973 visit-pairs(295 single pairs and 339 double pairs).The median age was 37 years(interquartile range:32-43 years).The incidence rates of sustained VLS,persistent viremia,viral rebound,and new suppression were 85.2%,4.3%,4.6%,and 5.7%,respectively.Young individuals aged 18-24 years had higher incidence of viral rebound compared to those 25 years or older(14.8%vs 4.3%;P=0.011).Of the visit-pairs that had sustained VLS during the first two visits(49.8%;n=485),56.7%exhibited sustained VLS throughout follow-up.Compared to having no education,having at least primary education was associated with an increased likelihood of sustained VLS(aIRR=1.09;95%CI:1.01-1.17).Those who presented with advanced HIV disease at baseline had a 12%reduced likelihood of sustained VLS(aIRR=0.88;95%CI:0.79-0.99).Achieving sustained VLS did not differ before or after adoption of the Treat All policy.When the analysis was repeated on imputed datasets,similar results were found.CONCLUSION Although most people living with HIV have sustained VLS in Rwanda,individuals without formal education,those presenting with advanced HIV,and younger individuals were lagging on multiple outcomes.Interventions tailored to these individuals would improve treatment outcomes to achieve epidemic control.
