In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asy...In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting.展开更多
Knee osteoarthritis(OA)is a debilitating condition with limited long-term treatment options.The therapeutic potential of mesenchymal stem cells(MSCs),particularly those derived from bone marrow aspirate concentrate,ha...Knee osteoarthritis(OA)is a debilitating condition with limited long-term treatment options.The therapeutic potential of mesenchymal stem cells(MSCs),particularly those derived from bone marrow aspirate concentrate,has garnered attention for cartilage repair in OA.While the iliac crest is the traditional site for bone marrow harvesting(BMH),associated morbidity has prompted the exploration of alternative sites such as the proximal tibia,distal femur,and proximal humerus.This paper reviews the impact of different harvesting sites on mesenchymal stem cell(MSC)yield,viability,and regenerative potential,emphasizing their relevance in knee OA treatment.The iliac crest consistently offers the highest MSC yield,but alternative sites within the surgical field of knee procedures offer comparable MSC characteristics with reduced morbidity.The integration of harvesting techniques into existing knee surgeries,such as total knee arthroplasty,provides a less invasive approach while maintaining thera-peutic efficacy.However,variability in MSC yield from these alternative sites underscores the need for further research to standardize techniques and optimize clinical outcomes.Future directions include large-scale comparative studies,advanced characterization of MSCs,and the development of personalized harvesting strategies.Ultimately,the findings suggest that optimizing the site of BMH can significantly influence the quality of MSC-based therapies for knee OA,enhancing their clinical utility and patient outcomes.展开更多
Recently,one of the main challenges facing the smart grid is insufficient computing resources and intermittent energy supply for various distributed components(such as monitoring systems for renewable energy power sta...Recently,one of the main challenges facing the smart grid is insufficient computing resources and intermittent energy supply for various distributed components(such as monitoring systems for renewable energy power stations).To solve the problem,we propose an energy harvesting based task scheduling and resource management framework to provide robust and low-cost edge computing services for smart grid.First,we formulate an energy consumption minimization problem with regard to task offloading,time switching,and resource allocation for mobile devices,which can be decoupled and transformed into a typical knapsack problem.Then,solutions are derived by two different algorithms.Furthermore,we deploy renewable energy and energy storage units at edge servers to tackle intermittency and instability problems.Finally,we design an energy management algorithm based on sampling average approximation for edge computing servers to derive the optimal charging/discharging strategies,number of energy storage units,and renewable energy utilization.The simulation results show the efficiency and superiority of our proposed framework.展开更多
Polymeric microwave actuators combining tissue-like softness with programmablemicrowave-responsive deformation hold great promise for mobile intelligentdevices and bionic soft robots. However, their application is cha...Polymeric microwave actuators combining tissue-like softness with programmablemicrowave-responsive deformation hold great promise for mobile intelligentdevices and bionic soft robots. However, their application is challenged by restricted electromagneticsensitivity and intricate sensing coupling. In this study, a sensitized polymericmicrowave actuator is fabricated by hybridizing a liquid crystal polymer with Ti3C2Tx(MXene). Compared to the initial counterpart, the hybrid polymer exhibits unique spacechargepolarization and interfacial polarization, resulting in significant improvements of230% in the dielectric loss factor and 830% in the apparent efficiency of electromagneticenergy harvest. The sensitized microwave actuation demonstrates as the shortenedresponse time of nearly 10 s, which is merely 13% of that for the initial shape memory polymer. Moreover, the ultra-low content of MXene (upto 0.15 wt%) benefits for maintaining the actuation potential of the hybrid polymer. An innovative self-powered sensing prototype that combinesdriving and piezoelectric polymers is developed, which generates real-time electric potential feedback (open-circuit potential of ~ 3 mV) duringactuation. The polarization-dominant energy conversion mechanism observed in the MXene-polymer hybrid structure furnishes a new approachfor developing efficient electromagnetic dissipative structures and shows potential for advancing polymeric electromagnetic intelligent devices.展开更多
High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,inclu...High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.展开更多
To further understand the performance of the energy harvesters under the influence of the wind force and the random excitation,this paper investigates the stochastic response of the bio-inspired energy harvesters subj...To further understand the performance of the energy harvesters under the influence of the wind force and the random excitation,this paper investigates the stochastic response of the bio-inspired energy harvesters subjected to Gaussian white noise and galloping excitation,simulating the flapping pattern of a seagull and its interaction with wind force.The equivalent linearization method is utilized to convert the original nonlinear model into the Itôstochastic differential equation by minimizing the mean squared error.Then,the second-order steady-state moments about the displacement,velocity,and voltage are derived by combining the moment analysis theory.The theoretical results are simulated numerically to analyze the stochastic response performance under different noise intensities,wind speeds,stiffness coefficients,and electromechanical coupling coefficients,time domain analysis is also conducted to study the performance of the harvester with different parameters.The results reveal that the mean square displacement and voltage increase with increasing the noise intensity and wind speed,larger absolute values of stiffness coefficient correspond to smaller mean square displacement and voltage,and larger electromechanical coupling coefficients can enhance the mean square voltage.Finally,the influence of wind speed and electromechanical coupling coefficient on the stationary probability density function(SPDF)is investigated,revealing the existence of a bimodal distribution under varying environmental conditions.展开更多
[Objective] This study aimed to explore agronomical measures to reduce the mechanical harvesting loss of rapeseed. [Method] Two rapeseed cultivars, Ningza 19 and Ningza 21, with certain pod-cracking resistance, were e...[Objective] This study aimed to explore agronomical measures to reduce the mechanical harvesting loss of rapeseed. [Method] Two rapeseed cultivars, Ningza 19 and Ningza 21, with certain pod-cracking resistance, were employed in field experiments. The two-factor split plot design and randomized complete block design were adopted. The rapeseed seeds were directly sowed with four different seeding rates （1.50, 2.25, 3.00 and 3.75 kg/hm2）. A total of four treatments were designed （112 500, 225 000, 337 500 and 450 000 plants/hm2）. After ripe, the rapeseed was harvested with harvester. Then the yield and harvesting loss rate were determined. [Result] When the planting density ranged from 112 500 to 450 000 plants/hm2, the mechanical harvesting loss rate was decreased with the increase of planting density （Ningza 19, 7.54%-4.01%; Ningza 21, 7.19%-3.81%）. The total loss rates were all below 5% for the high plant densities, 337 500 and 450 000 plants/hm2. High planting density had certain regulating effects on plant type of rapeseed, including reducing plant height, reducing biomass per plant, reducing branch pod numbers per plant, weakening crossing and tangling among stems and improving ripening uniformity of pods. All the changes above were all conducive to reducing mechanical harvesting loss. In addition, the test results showed after the pods grew to maturity, especially when pods were yellow and the moisture content in grains was reduced to 11%, the mechanical harvesting loss only accounted for about 1% of the total field loss. In addition, the shattering loss, caused by mild col- lision, represented more than 90%, and the cleaning loss, occurred during the threshing and cleaning process, represented 4%-8% of the total field loss. The un- harvesting loss accounted for approximately 1% of the total loss. The shattering loss is closely related to cultivar characteristics, planting density, production level and other agronomic factors. The cleaning loss is determined by properties of harvesting machines. The unharvesting loss depends on mechanical properties ad skills of workers or farmers who drive harvesting machines. [Conclusion] In order to reduce mechanical harvesting loss, the rapeseed production should be improved from the perspectives of agricultural machinery and agronomic measures.展开更多
Nowadays, we are witnessing an era marked by the autonomy of wireless devices and sensor networks without the aid of batteries. RF energy harvesting therefore becomes a promising alternative for battery dependence. Th...Nowadays, we are witnessing an era marked by the autonomy of wireless devices and sensor networks without the aid of batteries. RF energy harvesting therefore becomes a promising alternative for battery dependence. This work presents the design of an RF energy harvesting system consisting mainly of a rectenna (antenna and rectification circuit) and an adaptation circuit. First of all, we designed two dipole type antennas. One operates in the GSM 900 MHz band and the other in the GSM 1800 MHz band. The performances of the proposed antennas are provided by the ANSYS HFSS software. Secondly, we proposed two rectification circuits in order to obtain conversion efficiencies at 0 dBm of 64% for the system operating at the frequency of 900 MHz and 37% for the system at the frequency of 1800 MHz RF-DC. The rectifiers used are based on Schottky diodes. For maximum transfer of power between the antenna and the rectification circuit, L-type matching circuits have been proposed. This rectifier offers DC voltage values of 806 mV for the circuit at the frequency of 900 MHz and 616 mV for the circuit at the frequency of 1800 MHz. The adaptation circuits are obtained by carrying out simulations on the ADS (Advanced Design System) software.展开更多
This study focuses on wave energy harvesting by leveraging the impact-induced frequency of sea waves.It introduces a novel double-buoyed model based on the existing single-buoyed system to address the shortcomings of ...This study focuses on wave energy harvesting by leveraging the impact-induced frequency of sea waves.It introduces a novel double-buoyed model based on the existing single-buoyed system to address the shortcomings of previous systems.Notably,the traditional single-buoyed system,which is characterized by a long beam extending to the sea floor,proves impractical in deep-sea environments,especially in distant offshore regions.The proposed double-buoyed model replaces the long beam with a second buoy to increase energy harvesting efficiency.A parametric analysis that included the density and height of the first buoy and wave period was conducted to enhance the proposed model further.Results indicated that with the selection of optimal parameters,the power output of the double-buoyed system increased by approximately 13-fold,thereby enhancing the viability and efficiency of wave energy harvesting.展开更多
Unmanned Aerial Vehicles(UAVs)have been considered to have great potential in supporting reliable and timely data harvesting for Sensor Nodes(SNs)from an Internet of Things(IoT)perspective.However,due to physical limi...Unmanned Aerial Vehicles(UAVs)have been considered to have great potential in supporting reliable and timely data harvesting for Sensor Nodes(SNs)from an Internet of Things(IoT)perspective.However,due to physical limitations,UAVs are unable to further process the harvested data and have to rely on terrestrial servers,thus extra spectrum resource is needed to convey the harvested data.To avoid the cost of extra servers and spectrum resources,in this paper,we consider a UAV-based data harvesting network supported by a Cell-Free massive Multiple-Input-Multiple-Output(CF-mMIMO)system,where a UAV is used to collect and transmit data from SNs to the central processing unit of CF-mMIMO system for processing.In order to avoid using additional spectrum resources,the entire bandwidth is shared among radio access networks and wireless fronthaul links.Moreover,considering the limited capacity of the fronthaul links,the compress-and-forward scheme is adopted.In this work,in order to maximize the ergodically achievable sum rate of SNs,the power allocation of ground access points,the compression of fronthaul links,and also the bandwidth fraction between radio access networks and wireless fronthaul links are jointly optimized.To avoid the high overhead introduced by computing ergodically achievable rates,we introduce an approximate problem,using the large-dimensional random matrix theory,which relies only on statistical channel state information.We solve the nontrivial problem in three steps and propose an algorithm based on weighted minimum mean square error and Dinkelbach’s methods to find solutions.Finally,simulation results show that the proposed algorithm converges quickly and outperforms the baseline algorithms.展开更多
The shortage of freshwater has become a global challenge,exacerbated by global warming and the rapid growth of the world’s population.Researchers across various fields have made numerous attempts to efficiently colle...The shortage of freshwater has become a global challenge,exacerbated by global warming and the rapid growth of the world’s population.Researchers across various fields have made numerous attempts to efficiently collect freshwater for human use.These efforts include seawater desalination through reverse osmosis or distillation,sewage treatment technologies,and atmospheric water harvesting.However,after thoroughly exploring traditional freshwater harvesting methods,it has become clear that bio-inspired fog harvesting technology offers new prospects due to its unique advantages of efficiency and sustainability.This paper systematically introduces the current principles of fog harvesting and wettability mechanism found in nature.It reviews the research status of combining bionic fog harvesting materials with textile science from two distinct dimensions.Additionally,it describes the practical applications of fog harvesting materials in agriculture,industry,and domestic water use,analyzes their prospects and feasibility in engineering projects,discusses potential challenges in practical applications,and envisions future trends and directions for the development of these materials.展开更多
Climate variability significantly impacts agricultural water resources,particularly in regions like Vietnam's Plain of Reeds that heavily utilize rain-fed conditions.This study employs the FAO-AquaCrop model to es...Climate variability significantly impacts agricultural water resources,particularly in regions like Vietnam's Plain of Reeds that heavily utilize rain-fed conditions.This study employs the FAO-AquaCrop model to estimate current and future irrigation water needs for rice cultivation in this critical subregion,aiming to identify optimal sowing schedules(OSS)that enhance rainwater utilization and reduce irrigation dependency.The model was driven by current climate data and future projections(2041-2070 and 2071-2099)derived from downscaled Global Circulation Models under RCP4.5 and RCP8.5 scenarios.The AquaCrop model demonstrated robust performance during validation and calibration,with d-values(0.82-0.93)and R²values(0.85-0.92)indicating strong predictive accuracy for rice yield.Simulation results for efficient irrigation water potential(IWP)under RCP4.5 revealed that strategic shifts in sowing dates can substantially alter water requirements;for instance,advancing the winter-spring sowing to December 5th decreased IWP by 15.6%in the 2041-2070 period,while delaying summer-autumn crop sowing to April 20th increased IWP by 48.6%due to greater reliance on irrigation as rainfall patterns shift.Similar dynamic responses were observed for the 2071-2099 period and for autumn-winter crops.These findings underscore that AquaCrop modeling can effectively predict future irrigation needs and that adjusting cultivation calendars presents a viable,low-cost adaptation strategy.This approach allows farmers in the Plain of Reeds to optimize rainwater use,thereby reducing dependency on supplementary irrigation and mitigating the adverse impacts of climate variability,contributing to more sustainable agricultural water management.展开更多
Capturing of ambient energy is emerging as a transformative area in energy technology,potentially replacing batteries or significantly extending their lifespan.Harnessing of energy from ambient sources presents a sign...Capturing of ambient energy is emerging as a transformative area in energy technology,potentially replacing batteries or significantly extending their lifespan.Harnessing of energy from ambient sources presents a significant opportunity to support sustainable development while mitigating environmental issues.Repurposing energy that would otherwise be wasted from highconsumption systems such as engines and industrial furnaces is essential for reducing ecological footprints and moving toward carbon-neutral goals.Furthermore,compact energy harvesting technologies will play a pivotal role in powering the rapidly expanding Internet of Things,enabling innovative advancements in smart homes,cities,industries,and health care that elevate our living standards.To achieve significant advancements in energy harvesting technologies,the development of innovative materials is crucial for converting ambient energy into electricity.In this regard,two-dimensional(2D)materials,a rising star in the material world,are profoundly and technologically intriguing for energy harvesting.The exceptional atomic thickness,high surface-tovolume ratio,flexibility,and tunable band gap effectively enhance their electronic,optical,and chemical properties,making them a potential candidate for use in flexible electronics and wearable energy harvesting technologies.Consequently,these unique properties of 2D materials remarkably enhance their energy harvesting capabilities,including photovoltaic,triboelectric,thermoelectric,and piezoelectric energy harvesting.Here,we present a tutorial-style review of 2D materials for harvesting energy from different ambient sources(aimed particularly at guiding and educating researchers,especially those new to the field),which starts with a brief overview of the promising properties of 2D materials for energy harvesting,then looks deeply into its advantages as compared to traditional materials along with their 3D counterparts,followed by providing insight into the mechanisms and performance of 2D material-based energy harvesters in portable/wearable electronics,and finally,based on current progress,an overview of the challenges along with corresponding strategies are identified and discussed.展开更多
Nujiang farmers use the innovative dryland rice cultivation technology developed by a Chinese expert team to grow yields and income.As April ushers in spring,mist clings to the deep valleys of the Nujiang Grand Canyon...Nujiang farmers use the innovative dryland rice cultivation technology developed by a Chinese expert team to grow yields and income.As April ushers in spring,mist clings to the deep valleys of the Nujiang Grand Canyon in Southwest China’s Yunnan Province.High on a mountainside in Ziji Village,Daxingdi Town,Lushui City,Nujiang Lisu Autonomous Prefecture,at an altitude exceeding 1,300 metres,62-year-old Lisu villager Cha Wenxing is planting rice.These demonstration plots,cultivating high-quality upland rice,seem to float amongst the clouds.展开更多
Wheat(Triticum aestivum L.)is an important staple food crop in the world and supplies about 20%of human caloric and protein consumption(Giraldo et al.,2019;Xiao et al.,2022).Wheat production accounts for~30%of global ...Wheat(Triticum aestivum L.)is an important staple food crop in the world and supplies about 20%of human caloric and protein consumption(Giraldo et al.,2019;Xiao et al.,2022).Wheat production accounts for~30%of global cereal crops(Li et al.,2019).With the global population increasing and the frequency of natural disasters rising,enhancing wheat yield is crucial to meet food demand.Spike traits such as increased grain number per spike are key determinants of wheat yield.Pre-harvest sprouting(PHS)is a significant natural disaster that severely impacts grain yield and end-use quality of wheat(Tai et al.,2021,2024).展开更多
With the rapid advancement of the Internet of Things(IoT),the conventional power supply methods encounter challenges such as extensive wiring over long distances and frequent power source replacements.A sustainable po...With the rapid advancement of the Internet of Things(IoT),the conventional power supply methods encounter challenges such as extensive wiring over long distances and frequent power source replacements.A sustainable power supply is highly desirable for IoT devices.In this study,a novel hybrid triboelectricelectromagnetic harvester is proposed for efficient harvesting of wind energy to sustainably power low-power electronic devices,which integrates a number of sub-triboelectric energy harvesters(sub-TEHs)and subelectromagnetic energy harvesters(sub-EEHs).The sub-TEH can provide a peak output power of 67μW when the load resistance is 1 MΩ.The sub-EEH can provide a peak output power of 9.1 mW when the load resistance is 200Ω.After continuous operation for 15000 cycles,the outputs of both the sub-TEH and the sub-EEH experience no significant attenuation,which indicates good durability of the design.Under a wind speed of 11 m/s,over 100 LEDs can be lit up.And a temperature-humidity sensor is able to work continuously when powered by the hybrid energy harvester via a rectifier circuit.The hybrid energy harvester exhibits good output performance and long-term stability with a simple structure and low production cost,which has great potential in wind energy harvesting and wireless environmental monitoring applications.展开更多
Yongtao Yu,Yuelin Yu et al.Solvent-Resistant Wearable Triboelectric Nanogenerator for Energy-Harvesting and Self-Powered Sensors.Energy Environ.Mater.2024,7,e12700.On page 4 of this article,the first paragraph of 2.4,...Yongtao Yu,Yuelin Yu et al.Solvent-Resistant Wearable Triboelectric Nanogenerator for Energy-Harvesting and Self-Powered Sensors.Energy Environ.Mater.2024,7,e12700.On page 4 of this article,the first paragraph of 2.4,line 14(PDF version,same below),there is a spelling mistake of“sui,”.It should be changed to“suitable”.The denominator“dt”in the Equation(3)should be changed to“dt”.展开更多
The evolution of enabling technologies in wireless communications has paved the way for supporting novel applications with more demanding QoS requirements,but at the cost of increasing the complexity of optimizing the...The evolution of enabling technologies in wireless communications has paved the way for supporting novel applications with more demanding QoS requirements,but at the cost of increasing the complexity of optimizing the digital communication chain.In particular,Millimeter Wave(mmWave)communications provide an abundance of bandwidth,and energy harvesting supplies the network with a continual source of energy to facilitate self-sustainability;however,harnessing these technologies is challenging due to the stochastic dynamics of the mmWave channel as well as the random sporadic nature of the harvested energy.In this paper,we aim at the dynamic optimization of update transmissions in mmWave energy harvesting systems in terms of Age of Information(AoI).AoI has recently been introduced to quantify information freshness and is a more stringent QoS metric compared to conventional delay and throughput.However,most prior art has only addressed averagebased AoI metrics,which can be insufficient to capture the occurrence of rare but high-impact freshness violation events in time-critical scenarios.We formulate a control problem that aims to minimize the long-term entropic risk measure of AoI samples by configuring the“sense&transmit”of updates.Due to the high complexity of the exponential cost function,we reformulate the problem with an approximated mean-variance risk measure as the new objective.Under unknown system statistics,we propose a two-timescale model-free risk-sensitive reinforcement learning algorithm to compute a control policy that adapts to the trio of channel,energy,and AoI states.We evaluate the efficiency of the proposed scheme through extensive simulations.展开更多
Eco-friendly and antimicrobial globular protein lysozyme is widely produced for several commercial applications.Interestingly,it can also be able to convert mechanical and thermal energy into electricity due to its pi...Eco-friendly and antimicrobial globular protein lysozyme is widely produced for several commercial applications.Interestingly,it can also be able to convert mechanical and thermal energy into electricity due to its piezo-and pyroelectric nature.Here,we demonstrate engineering of lysozyme into piezoelectric devices that can exploit the potential of lysozyme as environmentally friendly,biocompatible material for mechanical energy harvesting and sensorics,especially in micropowered electronic applications.Noteworthy that this flexible,shape adaptive devices made of crystalline lysozyme obtained from hen egg white exhibited a longitudinal piezoelectric charge coefficient(d-2.7 pC N^(-1))and piezoelectric voltage coefficient(g-76.24 mVmN^(-1))which are comparable to those of quartz(-2.3 pC N^(-1) and 50 mVmN^(-1)).Simple finger tapping on bio-organic energy harvester(BEH)made of lysozyme produced up to 350 mV peak-to-peak voltage,and a maximum instantaneous power output of 2.2 nW cm^(-2).We also demonstrated that the BEH could be used for self-powered motion sensing for real-time monitoring of different body functions.These results pave the way toward self-powered,autonomous,environmental-friendly bio-organic devices for flexible energy harvesting,storage,and in wearable healthcare monitoring.展开更多
In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its thei...In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its their applications in extreme circumstances.Herein,an ultra-thin and highly flexible aramid nanofiber(ANF)/MXene(Ti_(3)C_(2)T_(x))/Ni nanochain composite paper was prepared through vacuum-assisted filtration and freeze-drying technology.Owing to the synergistic effect between ANF and MXene,the composite paper not only possessed excellent mechanical properties,which were able to withstand over 10,000 times its own weight,but also exhibited outstanding flame-retardant and controllable Joule heating ca-pabilities.Moreover,the mechanical energy capture characteristics of the composite paper-based TENG were evaluated,resulting in the open-circuit voltage(55.6 V),short-circuit current(0.62μA),and trans-ferred charge quantity(25μC).It also could enable self-powering as a wearable electronic device with an instantaneous power of 15.6μW at the optimal external resistance of 10 MΩ.This work is intended to set TENG as safe energy harvesting devices for reducing fire hazards,and will provide a new strategy to broaden the application ranges of TENG.展开更多
基金Supported by the National Natural Science Foundation of China(12261018)Universities Key Laboratory of Mathematical Modeling and Data Mining in Guizhou Province(2023013)。
文摘In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting.
文摘Knee osteoarthritis(OA)is a debilitating condition with limited long-term treatment options.The therapeutic potential of mesenchymal stem cells(MSCs),particularly those derived from bone marrow aspirate concentrate,has garnered attention for cartilage repair in OA.While the iliac crest is the traditional site for bone marrow harvesting(BMH),associated morbidity has prompted the exploration of alternative sites such as the proximal tibia,distal femur,and proximal humerus.This paper reviews the impact of different harvesting sites on mesenchymal stem cell(MSC)yield,viability,and regenerative potential,emphasizing their relevance in knee OA treatment.The iliac crest consistently offers the highest MSC yield,but alternative sites within the surgical field of knee procedures offer comparable MSC characteristics with reduced morbidity.The integration of harvesting techniques into existing knee surgeries,such as total knee arthroplasty,provides a less invasive approach while maintaining thera-peutic efficacy.However,variability in MSC yield from these alternative sites underscores the need for further research to standardize techniques and optimize clinical outcomes.Future directions include large-scale comparative studies,advanced characterization of MSCs,and the development of personalized harvesting strategies.Ultimately,the findings suggest that optimizing the site of BMH can significantly influence the quality of MSC-based therapies for knee OA,enhancing their clinical utility and patient outcomes.
基金supported in part by the National Natural Science Foundation of China under Grant No.61473066in part by the Natural Science Foundation of Hebei Province under Grant No.F2021501020+2 种基金in part by the S&T Program of Qinhuangdao under Grant No.202401A195in part by the Science Research Project of Hebei Education Department under Grant No.QN2025008in part by the Innovation Capability Improvement Plan Project of Hebei Province under Grant No.22567637H
文摘Recently,one of the main challenges facing the smart grid is insufficient computing resources and intermittent energy supply for various distributed components(such as monitoring systems for renewable energy power stations).To solve the problem,we propose an energy harvesting based task scheduling and resource management framework to provide robust and low-cost edge computing services for smart grid.First,we formulate an energy consumption minimization problem with regard to task offloading,time switching,and resource allocation for mobile devices,which can be decoupled and transformed into a typical knapsack problem.Then,solutions are derived by two different algorithms.Furthermore,we deploy renewable energy and energy storage units at edge servers to tackle intermittency and instability problems.Finally,we design an energy management algorithm based on sampling average approximation for edge computing servers to derive the optimal charging/discharging strategies,number of energy storage units,and renewable energy utilization.The simulation results show the efficiency and superiority of our proposed framework.
基金supported by the National Natural Science Foundation of China(No.52373280,52177014,51977009,52273257)。
文摘Polymeric microwave actuators combining tissue-like softness with programmablemicrowave-responsive deformation hold great promise for mobile intelligentdevices and bionic soft robots. However, their application is challenged by restricted electromagneticsensitivity and intricate sensing coupling. In this study, a sensitized polymericmicrowave actuator is fabricated by hybridizing a liquid crystal polymer with Ti3C2Tx(MXene). Compared to the initial counterpart, the hybrid polymer exhibits unique spacechargepolarization and interfacial polarization, resulting in significant improvements of230% in the dielectric loss factor and 830% in the apparent efficiency of electromagneticenergy harvest. The sensitized microwave actuation demonstrates as the shortenedresponse time of nearly 10 s, which is merely 13% of that for the initial shape memory polymer. Moreover, the ultra-low content of MXene (upto 0.15 wt%) benefits for maintaining the actuation potential of the hybrid polymer. An innovative self-powered sensing prototype that combinesdriving and piezoelectric polymers is developed, which generates real-time electric potential feedback (open-circuit potential of ~ 3 mV) duringactuation. The polarization-dominant energy conversion mechanism observed in the MXene-polymer hybrid structure furnishes a new approachfor developing efficient electromagnetic dissipative structures and shows potential for advancing polymeric electromagnetic intelligent devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272103 and 52072010)Beijing Natural Science Foundation(Grant Nos.2242029 and JL23004).
文摘High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.
文摘To further understand the performance of the energy harvesters under the influence of the wind force and the random excitation,this paper investigates the stochastic response of the bio-inspired energy harvesters subjected to Gaussian white noise and galloping excitation,simulating the flapping pattern of a seagull and its interaction with wind force.The equivalent linearization method is utilized to convert the original nonlinear model into the Itôstochastic differential equation by minimizing the mean squared error.Then,the second-order steady-state moments about the displacement,velocity,and voltage are derived by combining the moment analysis theory.The theoretical results are simulated numerically to analyze the stochastic response performance under different noise intensities,wind speeds,stiffness coefficients,and electromechanical coupling coefficients,time domain analysis is also conducted to study the performance of the harvester with different parameters.The results reveal that the mean square displacement and voltage increase with increasing the noise intensity and wind speed,larger absolute values of stiffness coefficient correspond to smaller mean square displacement and voltage,and larger electromechanical coupling coefficients can enhance the mean square voltage.Finally,the influence of wind speed and electromechanical coupling coefficient on the stationary probability density function(SPDF)is investigated,revealing the existence of a bimodal distribution under varying environmental conditions.
基金Supported by National High Technology Research and Development Program of China(863 Program)(2011AA10A10403)National Key Technology Research and Development Program(2010BAD01B06)+1 种基金Jiangsu Province Science and Technology Support Program(BE2012327)Jiangsu Agricultural Science and Technology Innovation Fund(CX(14)2003)~~
文摘[Objective] This study aimed to explore agronomical measures to reduce the mechanical harvesting loss of rapeseed. [Method] Two rapeseed cultivars, Ningza 19 and Ningza 21, with certain pod-cracking resistance, were employed in field experiments. The two-factor split plot design and randomized complete block design were adopted. The rapeseed seeds were directly sowed with four different seeding rates （1.50, 2.25, 3.00 and 3.75 kg/hm2）. A total of four treatments were designed （112 500, 225 000, 337 500 and 450 000 plants/hm2）. After ripe, the rapeseed was harvested with harvester. Then the yield and harvesting loss rate were determined. [Result] When the planting density ranged from 112 500 to 450 000 plants/hm2, the mechanical harvesting loss rate was decreased with the increase of planting density （Ningza 19, 7.54%-4.01%; Ningza 21, 7.19%-3.81%）. The total loss rates were all below 5% for the high plant densities, 337 500 and 450 000 plants/hm2. High planting density had certain regulating effects on plant type of rapeseed, including reducing plant height, reducing biomass per plant, reducing branch pod numbers per plant, weakening crossing and tangling among stems and improving ripening uniformity of pods. All the changes above were all conducive to reducing mechanical harvesting loss. In addition, the test results showed after the pods grew to maturity, especially when pods were yellow and the moisture content in grains was reduced to 11%, the mechanical harvesting loss only accounted for about 1% of the total field loss. In addition, the shattering loss, caused by mild col- lision, represented more than 90%, and the cleaning loss, occurred during the threshing and cleaning process, represented 4%-8% of the total field loss. The un- harvesting loss accounted for approximately 1% of the total loss. The shattering loss is closely related to cultivar characteristics, planting density, production level and other agronomic factors. The cleaning loss is determined by properties of harvesting machines. The unharvesting loss depends on mechanical properties ad skills of workers or farmers who drive harvesting machines. [Conclusion] In order to reduce mechanical harvesting loss, the rapeseed production should be improved from the perspectives of agricultural machinery and agronomic measures.
文摘Nowadays, we are witnessing an era marked by the autonomy of wireless devices and sensor networks without the aid of batteries. RF energy harvesting therefore becomes a promising alternative for battery dependence. This work presents the design of an RF energy harvesting system consisting mainly of a rectenna (antenna and rectification circuit) and an adaptation circuit. First of all, we designed two dipole type antennas. One operates in the GSM 900 MHz band and the other in the GSM 1800 MHz band. The performances of the proposed antennas are provided by the ANSYS HFSS software. Secondly, we proposed two rectification circuits in order to obtain conversion efficiencies at 0 dBm of 64% for the system operating at the frequency of 900 MHz and 37% for the system at the frequency of 1800 MHz RF-DC. The rectifiers used are based on Schottky diodes. For maximum transfer of power between the antenna and the rectification circuit, L-type matching circuits have been proposed. This rectifier offers DC voltage values of 806 mV for the circuit at the frequency of 900 MHz and 616 mV for the circuit at the frequency of 1800 MHz. The adaptation circuits are obtained by carrying out simulations on the ADS (Advanced Design System) software.
文摘This study focuses on wave energy harvesting by leveraging the impact-induced frequency of sea waves.It introduces a novel double-buoyed model based on the existing single-buoyed system to address the shortcomings of previous systems.Notably,the traditional single-buoyed system,which is characterized by a long beam extending to the sea floor,proves impractical in deep-sea environments,especially in distant offshore regions.The proposed double-buoyed model replaces the long beam with a second buoy to increase energy harvesting efficiency.A parametric analysis that included the density and height of the first buoy and wave period was conducted to enhance the proposed model further.Results indicated that with the selection of optimal parameters,the power output of the double-buoyed system increased by approximately 13-fold,thereby enhancing the viability and efficiency of wave energy harvesting.
基金supported in part by the Jiangsu Provincial Key Research and Development Program(No.BE2022068-2)in part by the National Natural Science Foundation of China under Grant 62201285+1 种基金in part by Young Elite Scientists Sponsorship Program by CAST under Grant 2022QNRC001in part by the Postgraduate Research&Practice Innovation Program of Jiangsu Province under Grant KYCX23_1012.
文摘Unmanned Aerial Vehicles(UAVs)have been considered to have great potential in supporting reliable and timely data harvesting for Sensor Nodes(SNs)from an Internet of Things(IoT)perspective.However,due to physical limitations,UAVs are unable to further process the harvested data and have to rely on terrestrial servers,thus extra spectrum resource is needed to convey the harvested data.To avoid the cost of extra servers and spectrum resources,in this paper,we consider a UAV-based data harvesting network supported by a Cell-Free massive Multiple-Input-Multiple-Output(CF-mMIMO)system,where a UAV is used to collect and transmit data from SNs to the central processing unit of CF-mMIMO system for processing.In order to avoid using additional spectrum resources,the entire bandwidth is shared among radio access networks and wireless fronthaul links.Moreover,considering the limited capacity of the fronthaul links,the compress-and-forward scheme is adopted.In this work,in order to maximize the ergodically achievable sum rate of SNs,the power allocation of ground access points,the compression of fronthaul links,and also the bandwidth fraction between radio access networks and wireless fronthaul links are jointly optimized.To avoid the high overhead introduced by computing ergodically achievable rates,we introduce an approximate problem,using the large-dimensional random matrix theory,which relies only on statistical channel state information.We solve the nontrivial problem in three steps and propose an algorithm based on weighted minimum mean square error and Dinkelbach’s methods to find solutions.Finally,simulation results show that the proposed algorithm converges quickly and outperforms the baseline algorithms.
基金Shandong Provincial Key Research and Development Program(Major Scientific and Technological Innovation Project)(2021CXGC011001)Huafon Microfibre(Jiangsu)Co.Ltd.(2021120011000234)+1 种基金Textile Vision Basic Research Program(J202306)China Postdoctoral Science Foundation(No.2023M732103).
文摘The shortage of freshwater has become a global challenge,exacerbated by global warming and the rapid growth of the world’s population.Researchers across various fields have made numerous attempts to efficiently collect freshwater for human use.These efforts include seawater desalination through reverse osmosis or distillation,sewage treatment technologies,and atmospheric water harvesting.However,after thoroughly exploring traditional freshwater harvesting methods,it has become clear that bio-inspired fog harvesting technology offers new prospects due to its unique advantages of efficiency and sustainability.This paper systematically introduces the current principles of fog harvesting and wettability mechanism found in nature.It reviews the research status of combining bionic fog harvesting materials with textile science from two distinct dimensions.Additionally,it describes the practical applications of fog harvesting materials in agriculture,industry,and domestic water use,analyzes their prospects and feasibility in engineering projects,discusses potential challenges in practical applications,and envisions future trends and directions for the development of these materials.
文摘Climate variability significantly impacts agricultural water resources,particularly in regions like Vietnam's Plain of Reeds that heavily utilize rain-fed conditions.This study employs the FAO-AquaCrop model to estimate current and future irrigation water needs for rice cultivation in this critical subregion,aiming to identify optimal sowing schedules(OSS)that enhance rainwater utilization and reduce irrigation dependency.The model was driven by current climate data and future projections(2041-2070 and 2071-2099)derived from downscaled Global Circulation Models under RCP4.5 and RCP8.5 scenarios.The AquaCrop model demonstrated robust performance during validation and calibration,with d-values(0.82-0.93)and R²values(0.85-0.92)indicating strong predictive accuracy for rice yield.Simulation results for efficient irrigation water potential(IWP)under RCP4.5 revealed that strategic shifts in sowing dates can substantially alter water requirements;for instance,advancing the winter-spring sowing to December 5th decreased IWP by 15.6%in the 2041-2070 period,while delaying summer-autumn crop sowing to April 20th increased IWP by 48.6%due to greater reliance on irrigation as rainfall patterns shift.Similar dynamic responses were observed for the 2071-2099 period and for autumn-winter crops.These findings underscore that AquaCrop modeling can effectively predict future irrigation needs and that adjusting cultivation calendars presents a viable,low-cost adaptation strategy.This approach allows farmers in the Plain of Reeds to optimize rainwater use,thereby reducing dependency on supplementary irrigation and mitigating the adverse impacts of climate variability,contributing to more sustainable agricultural water management.
基金supported by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(MSIT),Project No.RS-2025-24533268.
文摘Capturing of ambient energy is emerging as a transformative area in energy technology,potentially replacing batteries or significantly extending their lifespan.Harnessing of energy from ambient sources presents a significant opportunity to support sustainable development while mitigating environmental issues.Repurposing energy that would otherwise be wasted from highconsumption systems such as engines and industrial furnaces is essential for reducing ecological footprints and moving toward carbon-neutral goals.Furthermore,compact energy harvesting technologies will play a pivotal role in powering the rapidly expanding Internet of Things,enabling innovative advancements in smart homes,cities,industries,and health care that elevate our living standards.To achieve significant advancements in energy harvesting technologies,the development of innovative materials is crucial for converting ambient energy into electricity.In this regard,two-dimensional(2D)materials,a rising star in the material world,are profoundly and technologically intriguing for energy harvesting.The exceptional atomic thickness,high surface-tovolume ratio,flexibility,and tunable band gap effectively enhance their electronic,optical,and chemical properties,making them a potential candidate for use in flexible electronics and wearable energy harvesting technologies.Consequently,these unique properties of 2D materials remarkably enhance their energy harvesting capabilities,including photovoltaic,triboelectric,thermoelectric,and piezoelectric energy harvesting.Here,we present a tutorial-style review of 2D materials for harvesting energy from different ambient sources(aimed particularly at guiding and educating researchers,especially those new to the field),which starts with a brief overview of the promising properties of 2D materials for energy harvesting,then looks deeply into its advantages as compared to traditional materials along with their 3D counterparts,followed by providing insight into the mechanisms and performance of 2D material-based energy harvesters in portable/wearable electronics,and finally,based on current progress,an overview of the challenges along with corresponding strategies are identified and discussed.
文摘Nujiang farmers use the innovative dryland rice cultivation technology developed by a Chinese expert team to grow yields and income.As April ushers in spring,mist clings to the deep valleys of the Nujiang Grand Canyon in Southwest China’s Yunnan Province.High on a mountainside in Ziji Village,Daxingdi Town,Lushui City,Nujiang Lisu Autonomous Prefecture,at an altitude exceeding 1,300 metres,62-year-old Lisu villager Cha Wenxing is planting rice.These demonstration plots,cultivating high-quality upland rice,seem to float amongst the clouds.
基金supported by the National Key Research and Development Program of China(2023YFD1200403 and 2023YFF1000600)the Innovation Program of Chinese Academy of Agricultural Sciences。
文摘Wheat(Triticum aestivum L.)is an important staple food crop in the world and supplies about 20%of human caloric and protein consumption(Giraldo et al.,2019;Xiao et al.,2022).Wheat production accounts for~30%of global cereal crops(Li et al.,2019).With the global population increasing and the frequency of natural disasters rising,enhancing wheat yield is crucial to meet food demand.Spike traits such as increased grain number per spike are key determinants of wheat yield.Pre-harvest sprouting(PHS)is a significant natural disaster that severely impacts grain yield and end-use quality of wheat(Tai et al.,2021,2024).
基金financial support from National Natural Sciences Foundation of China(Grant No.12272324 and Grant No.12432002)Central University Science and Technology Innovation Project(Grant No.2682024CX096)+1 种基金Sichuan Provincial Natural Science Foundation Youth Fund Project(Grant No.2025ZNSFSC0835)Another project(Grant No.52305209)is also acknowledged.
文摘With the rapid advancement of the Internet of Things(IoT),the conventional power supply methods encounter challenges such as extensive wiring over long distances and frequent power source replacements.A sustainable power supply is highly desirable for IoT devices.In this study,a novel hybrid triboelectricelectromagnetic harvester is proposed for efficient harvesting of wind energy to sustainably power low-power electronic devices,which integrates a number of sub-triboelectric energy harvesters(sub-TEHs)and subelectromagnetic energy harvesters(sub-EEHs).The sub-TEH can provide a peak output power of 67μW when the load resistance is 1 MΩ.The sub-EEH can provide a peak output power of 9.1 mW when the load resistance is 200Ω.After continuous operation for 15000 cycles,the outputs of both the sub-TEH and the sub-EEH experience no significant attenuation,which indicates good durability of the design.Under a wind speed of 11 m/s,over 100 LEDs can be lit up.And a temperature-humidity sensor is able to work continuously when powered by the hybrid energy harvester via a rectifier circuit.The hybrid energy harvester exhibits good output performance and long-term stability with a simple structure and low production cost,which has great potential in wind energy harvesting and wireless environmental monitoring applications.
文摘Yongtao Yu,Yuelin Yu et al.Solvent-Resistant Wearable Triboelectric Nanogenerator for Energy-Harvesting and Self-Powered Sensors.Energy Environ.Mater.2024,7,e12700.On page 4 of this article,the first paragraph of 2.4,line 14(PDF version,same below),there is a spelling mistake of“sui,”.It should be changed to“suitable”.The denominator“dt”in the Equation(3)should be changed to“dt”.
文摘The evolution of enabling technologies in wireless communications has paved the way for supporting novel applications with more demanding QoS requirements,but at the cost of increasing the complexity of optimizing the digital communication chain.In particular,Millimeter Wave(mmWave)communications provide an abundance of bandwidth,and energy harvesting supplies the network with a continual source of energy to facilitate self-sustainability;however,harnessing these technologies is challenging due to the stochastic dynamics of the mmWave channel as well as the random sporadic nature of the harvested energy.In this paper,we aim at the dynamic optimization of update transmissions in mmWave energy harvesting systems in terms of Age of Information(AoI).AoI has recently been introduced to quantify information freshness and is a more stringent QoS metric compared to conventional delay and throughput.However,most prior art has only addressed averagebased AoI metrics,which can be insufficient to capture the occurrence of rare but high-impact freshness violation events in time-critical scenarios.We formulate a control problem that aims to minimize the long-term entropic risk measure of AoI samples by configuring the“sense&transmit”of updates.Due to the high complexity of the exponential cost function,we reformulate the problem with an approximated mean-variance risk measure as the new objective.Under unknown system statistics,we propose a two-timescale model-free risk-sensitive reinforcement learning algorithm to compute a control policy that adapts to the trio of channel,energy,and AoI states.We evaluate the efficiency of the proposed scheme through extensive simulations.
基金supported by CURAM-Science Foundation Ireland(SFI)center for medical devices(Grant Number 13/RC/2073_P2)Irish Research Council Postdoctoral Fellowship(GOIPD/2021/928):Disposable,biodegradable,endoscopic ultrasonic imaging probe(DISPOSON)+1 种基金SFI Opportunistic Fund(no.12/RI/2345/SOF)is acknowledged for the NTEGRA Hybrid Nanoscope used in Piezoresponse Force MicroscopyOpen access funding provided by IReL.
文摘Eco-friendly and antimicrobial globular protein lysozyme is widely produced for several commercial applications.Interestingly,it can also be able to convert mechanical and thermal energy into electricity due to its piezo-and pyroelectric nature.Here,we demonstrate engineering of lysozyme into piezoelectric devices that can exploit the potential of lysozyme as environmentally friendly,biocompatible material for mechanical energy harvesting and sensorics,especially in micropowered electronic applications.Noteworthy that this flexible,shape adaptive devices made of crystalline lysozyme obtained from hen egg white exhibited a longitudinal piezoelectric charge coefficient(d-2.7 pC N^(-1))and piezoelectric voltage coefficient(g-76.24 mVmN^(-1))which are comparable to those of quartz(-2.3 pC N^(-1) and 50 mVmN^(-1)).Simple finger tapping on bio-organic energy harvester(BEH)made of lysozyme produced up to 350 mV peak-to-peak voltage,and a maximum instantaneous power output of 2.2 nW cm^(-2).We also demonstrated that the BEH could be used for self-powered motion sensing for real-time monitoring of different body functions.These results pave the way toward self-powered,autonomous,environmental-friendly bio-organic devices for flexible energy harvesting,storage,and in wearable healthcare monitoring.
基金financially supported by the Zhejiang Provin-cial Natural Science Foundation of China(No.LQ22E030016)the National Natural Science Foundation of China(Nos.52275137,51705467),the China Postdoctoral Science Foundation(No.2022M722831)+2 种基金the Postdoctoral Research Selected Funding Project of Zhejiang Province(No.ZJ2022063)the Self-Topic Fund of Zhe-jiang Normal University(No.2020ZS04)the National Key Re-search and Development Program of China(No.2018YFE0199100).
文摘In recent years,polymer-based triboelectric nanogenerators(TENGs)have been increasingly applied in the field of flexible wearable electronics.However,the lack of flame retardancy of existing TENGs greatly lim-its their applications in extreme circumstances.Herein,an ultra-thin and highly flexible aramid nanofiber(ANF)/MXene(Ti_(3)C_(2)T_(x))/Ni nanochain composite paper was prepared through vacuum-assisted filtration and freeze-drying technology.Owing to the synergistic effect between ANF and MXene,the composite paper not only possessed excellent mechanical properties,which were able to withstand over 10,000 times its own weight,but also exhibited outstanding flame-retardant and controllable Joule heating ca-pabilities.Moreover,the mechanical energy capture characteristics of the composite paper-based TENG were evaluated,resulting in the open-circuit voltage(55.6 V),short-circuit current(0.62μA),and trans-ferred charge quantity(25μC).It also could enable self-powering as a wearable electronic device with an instantaneous power of 15.6μW at the optimal external resistance of 10 MΩ.This work is intended to set TENG as safe energy harvesting devices for reducing fire hazards,and will provide a new strategy to broaden the application ranges of TENG.
