Ambient energy harvesting from various renewable sources,including solar,thermal,wave,droplet,wind,and biomechanical energy,presents a promising solution for sustainable power generation and battery-free Internet of T...Ambient energy harvesting from various renewable sources,including solar,thermal,wave,droplet,wind,and biomechanical energy,presents a promising solution for sustainable power generation and battery-free Internet of Things networks.However,these technologies face significant challenges in energy conversion efficiency and device durability due to environmental factors such as surface contamination,moisture accumulation,and biofouling.Superhydrophobic surfaces address these limitations through their unique properties of self-cleaning,water-repellent,and anti-bacterial,significantly enhancing energy harvesting performance and reliability.This review systematically summarizes recent advances in superhydrophobic surface-enhanced energy harvesting devices based on various mechanisms,including photovoltaics,electromagnetism,piezoelectricity,triboelectricity,thermoelectricity,and electrical double-layer dynamics.We first provide an updated overview of superhydrophobic surfaces,including their design strategies and fabrication methods.Then,we offer a comprehensive summary of their role in optimizing various energy harvesting devices.Finally,we discuss prospective challenges,potential solutions,and recommendations for future developments within this emerging interdisciplinary field.展开更多
Governed by the second law of thermodynamics,waste heat generation is inevitable and has been a major source of energy loss and environmental concern in human society.Harvesting waste heat into useful energy has thus ...Governed by the second law of thermodynamics,waste heat generation is inevitable and has been a major source of energy loss and environmental concern in human society.Harvesting waste heat into useful energy has thus become a paramount priority,but has remained challenging with efficiency and cost constraints.Thermoelectric generators(TEGs),which convert heat into electricity whenever there is a temperature difference,play a crucial role in waste heat harvesting.However,sustaining the temperature difference for uninterrupted and high-power density electricity generation is a major challenge in TEGs to achieve practical applications due to the thermal equilibrium.Here,we demonstrate a diurnal waste heat harvester by integrating a high-power radiative cooling film as the cool end of TEGs to enable a large and continuous temperature difference.Significant voltage increase from 30.0 mV to 65.7 mV was achieved,leading to a dramatic power density enhancement of 4.8 times from 35.2 mW m^(-2)to 168.6 mW m^(-2).In an open zone,an ultra-high power density of 2.76 W m^(-2)was achieved at a heat source temperature of 80°C,exceeding the performance of state-of-the-art radiatively cooled TEGs.More importantly,a portable and foldable thermal energy harvesting prototype composed of 24 TEGs arranged in an array has been constructed.When attached to a hot object(e.g.a car engine hood),it can output 5 V to charge personal electronics(e.g.a cellphone),making it a promising practical device for harvesting waste heat in a wide range of outdoor applications.展开更多
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
Efficient solar light harvesting is essential for high-performance photocatalysts.Here,Rigorous CoupledWave Analysis(RCWA)computational method is used to investigate and optimize the optical absorption of TiO_(2)-BiVO...Efficient solar light harvesting is essential for high-performance photocatalysts.Here,Rigorous CoupledWave Analysis(RCWA)computational method is used to investigate and optimize the optical absorption of TiO_(2)-BiVO_(4) inverse opal(IO)structures under varying light incidence angles and pore-filling medium(air or water).Simulations were validated against experimental reflectance data.They revealed that small-pore IOs strongly absorb in the UV-C and UV-B regions due to the slow photon effect,making them ideal for sterilization and water disinfection.Medium-and large-pore IOs benefit from additional slow photon effect at the 2nd order photonic band gap,enhancing absorption across both UV and visible regions.Medium-pore IOs are suited for indoor air treatment and water purification,while large-pore IOs with the highest photon flux enhancement enable solar-driven photocatalysis such as outdoor pollutant removal and hydrogen production.For all tested IO designs,the absorbed photon flux exceeds that of equivalent planar slabs,highlighting the advantage of photonic structuring for sustainable photocatalytic applications.展开更多
Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factor...Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factors:prey refuge and harvesting.The model also integrates disease transmission within the predator population,adding an important layer of realism.Using rigorous mathematical techniques,we demonstrate the existence and uniqueness of a global positive solution,thereby confirming the model's biological feasibility.We further derive sufficient conditions for two key ecological scenarios:stochastic permanence,which ensures the sustained co-existence of prey and predators over time,and extinction,where one or both populations decline to zero.The interplay between prey refuge and harvesting is thoroughly examined to understand their combined impact on population dynamics.All theoretical results are validated by detailed numerical simulations,highlighting the applicability of the model to real-world ecological systems.From the simulation results,we observed that with an adequate level of prey refuge and predator harvesting,the susceptible predator and prey coexist with extensive oscillations,while the infected predator population was moving towards extinction.In addition,we have investigated the effect of disease transmission on system dynamics.Our results show that,as the transmission rate of disease increases,the susceptible predator approaches extinction,whereas,on the other hand,when it declines,the susceptible predator shows robust oscillations while the infected approaches extinction.In both cases,the prey population demonstrates robust stability due to the prey refuge.Our findings show that the management of harvesting and the prey refuge can be effective ecological tactics for disease control and species protection under stochastic environmental effects.展开更多
Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,cou...Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,could become a sustainable alternative.Sorption-based atmospheric water harvesting(SAWH)has emerged as an available solution,yet conventional desorption methods relying on energy-intensive electrical heating hinder its scalability.Herein,a photothermal hygroscopic sponge has been developed for solar-driven atmospheric water harvesting.The composites combine a malleable melamine sponge skeleton,lithium chloride as a hygroscopic agent,and hydrangea-like molybdenum disulfide as a photothermal component,forming a multiscale“pore-film”cross-linked structure by an eco-friendly immersion-freeze-drying method.The optimized sample achieves exceptional hygroscopic capacity(3.92 g/g at 90%RH)and freshwater production efficiency(87.77%),which is attributed to synergistic effects of porous skeleton based crosslinked structures and“pore-film”structures,and outstanding photothermal conversion efficiency of MoS2.The unique structure could stabilize LiCl to prevent leakage,increase mass transfer effectiveness of whole SWAH process,and enable flexibility for diverse applications.We carried out outdoor experiments to demonstrate a solar-driven water production rate of 4.22 L m^(-2) d^(-1) without external energy input.This work provides insights into sustainable freshwater generation and promotes green energy utilization in addressing global water scarcity.展开更多
China and Laos are close neighbors with a long-standing friendship.Since the early 2000s,China has supported Laos'economic and social development through wide-ranging cooperation projects,all guided by the vision ...China and Laos are close neighbors with a long-standing friendship.Since the early 2000s,China has supported Laos'economic and social development through wide-ranging cooperation projects,all guided by the vision of a community with a shared future.As this vision takes deeper root,many aid projects have moved from blueprint to reality,delivering tangible benefits across towns and villages and improving the lives of ordinary Lao people while further strengthening bilateral ties.展开更多
In this paper,the dynamics of a Leslie-Gower predator-prey model with weak nonlin-ear harvesting and prey-taxis is discussed.By comparing and analyzing the differences between ordinary differential systems and chemota...In this paper,the dynamics of a Leslie-Gower predator-prey model with weak nonlin-ear harvesting and prey-taxis is discussed.By comparing and analyzing the differences between ordinary differential systems and chemotaxis systems in the stability of equilibrium points,the influence mechanism of chemotaxis on the dynamic behavior of the system is deeply studied.Theoretical analysis shows that chemotaxis significantly changes the stability characteristics of the system,and the reliability of theoretical results is further verified by numerical simulation.展开更多
The rapid advancement of wearable electronic devices has paved the way for a more intelligent and interconnected world.However,ensuring the sustainable energy supply for these devices remains a critical challenge,part...The rapid advancement of wearable electronic devices has paved the way for a more intelligent and interconnected world.However,ensuring the sustainable energy supply for these devices remains a critical challenge,particularly for specialized populations and professionals in demanding environments,where a lack of power can pose life-threatening risks.Herein,we propose a mechanically intelligent biomechanical energy harvesting approach that adapts to complex human motion excitations,thereby improving the energy harvesting performance.Leveraging a mechanical intelligence mechanism,the energy harvester aligns with human physiological habits,selectively activating or deactivating as needed.The system can also adapt to excitations of varying directions,amplitudes,and frequencies.Furthermore,the string tension helps reduce the impact forces on the knee joint during foot strikes.A theoretical model for the biomechanical energy harvesting system is developed to describe its dynamic and electrical characteristics,and a prototype is fabricated and tested under diverse conditions.The experimental results are in good agreement with the simulation trends,validating the effectiveness of the theoretical model.A test subject running at 8 km/h for 90 seconds can successfully power a smartphone for 20 seconds,demonstrating the viability of self-powered applications.This mechanically intelligent biomechanical energy harvesting method holds a promising solution for the sustainable power supply for wearable electronic devices.展开更多
Triboelectric nanogenerators(TENGs)show promise for sustainable energy harvesting;however,their development faces challenges due to the limited performance of traditional polymers,such as PDMS and PTFE.This drives int...Triboelectric nanogenerators(TENGs)show promise for sustainable energy harvesting;however,their development faces challenges due to the limited performance of traditional polymers,such as PDMS and PTFE.This drives interest in metal-organic frameworks(MOFs),which offer high surface area,tunable porosity,and customizable chemical functionality that can help overcome these limitations.In this review,we thoroughly analyze the application of MOFs in TENGs by exploring structural design strategies,ligand modifications,and layer engineering,as well as assessing performance results from recent studies.We highlight essential findings indicating that electron-withdrawing groups,such as-NO_(2),-F,and-SO_(3)H,notably increase tribonegativity.Additionally,doping with conductive nanomaterials and employing machine learning approaches further boost power density.Finally,we propose that future advancements in this area should focus on addressing environmental sensitivity,mechanical brittleness,and synthesis complexity through molecular-level tailoring combined with scalable device engineering,ultimately paving the way for durable,high-efficiency MOF-based TENGs.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
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
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
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
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 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
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
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
基金supported by the National Natural Science Foundation of China(62404081)Guangdong Basic and Applied Basic Research Foundation(2024A1515011907)Xiaomi Young Talents Program.
文摘Ambient energy harvesting from various renewable sources,including solar,thermal,wave,droplet,wind,and biomechanical energy,presents a promising solution for sustainable power generation and battery-free Internet of Things networks.However,these technologies face significant challenges in energy conversion efficiency and device durability due to environmental factors such as surface contamination,moisture accumulation,and biofouling.Superhydrophobic surfaces address these limitations through their unique properties of self-cleaning,water-repellent,and anti-bacterial,significantly enhancing energy harvesting performance and reliability.This review systematically summarizes recent advances in superhydrophobic surface-enhanced energy harvesting devices based on various mechanisms,including photovoltaics,electromagnetism,piezoelectricity,triboelectricity,thermoelectricity,and electrical double-layer dynamics.We first provide an updated overview of superhydrophobic surfaces,including their design strategies and fabrication methods.Then,we offer a comprehensive summary of their role in optimizing various energy harvesting devices.Finally,we discuss prospective challenges,potential solutions,and recommendations for future developments within this emerging interdisciplinary field.
基金support from the Key Research and Development Program of Shandong Province(No.2022SFGC0501)Shenzhen Science and Technology Program(International Cooperation Research)(No.GJHZ20240218113407015)+9 种基金Shenzhen Fundamental Research Program(Natural Science Foundation)(No.JCYJ20240813175900001)support from the Australian Research Council through the Discovery Project scheme(Grant No.DP190103186,DP220100603)support through the Future Fellowship scheme(Grant No.FT210100806)Discovery Project scheme(Grant No.DP250100980)Linkage Project scheme(LP210200345)the Industrial Transformation Research Hubs(Grant No.IH240100009)support through the Future Fellowship scheme(Grant No.FT220100559)Linkage Projects(Grant No.LP210100467)support through the Discovery Early Career Researcher Award scheme(DE230100383)support from the Natural Science Foundation of Shandong Province(Grant No.ZR2021ME162).
文摘Governed by the second law of thermodynamics,waste heat generation is inevitable and has been a major source of energy loss and environmental concern in human society.Harvesting waste heat into useful energy has thus become a paramount priority,but has remained challenging with efficiency and cost constraints.Thermoelectric generators(TEGs),which convert heat into electricity whenever there is a temperature difference,play a crucial role in waste heat harvesting.However,sustaining the temperature difference for uninterrupted and high-power density electricity generation is a major challenge in TEGs to achieve practical applications due to the thermal equilibrium.Here,we demonstrate a diurnal waste heat harvester by integrating a high-power radiative cooling film as the cool end of TEGs to enable a large and continuous temperature difference.Significant voltage increase from 30.0 mV to 65.7 mV was achieved,leading to a dramatic power density enhancement of 4.8 times from 35.2 mW m^(-2)to 168.6 mW m^(-2).In an open zone,an ultra-high power density of 2.76 W m^(-2)was achieved at a heat source temperature of 80°C,exceeding the performance of state-of-the-art radiatively cooled TEGs.More importantly,a portable and foldable thermal energy harvesting prototype composed of 24 TEGs arranged in an array has been constructed.When attached to a hot object(e.g.a car engine hood),it can output 5 V to charge personal electronics(e.g.a cellphone),making it a promising practical device for harvesting waste heat in a wide range of outdoor applications.
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.
基金supported by the FNRS-FRFC,the Walloon Region,and the University of Namur(Conventions No.2.5020.11,GEQ U.G006.15,1610468,RW/GEQ2016 et U.G011.22)funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska Curie grant agreement n°101034383。
文摘Efficient solar light harvesting is essential for high-performance photocatalysts.Here,Rigorous CoupledWave Analysis(RCWA)computational method is used to investigate and optimize the optical absorption of TiO_(2)-BiVO_(4) inverse opal(IO)structures under varying light incidence angles and pore-filling medium(air or water).Simulations were validated against experimental reflectance data.They revealed that small-pore IOs strongly absorb in the UV-C and UV-B regions due to the slow photon effect,making them ideal for sterilization and water disinfection.Medium-and large-pore IOs benefit from additional slow photon effect at the 2nd order photonic band gap,enhancing absorption across both UV and visible regions.Medium-pore IOs are suited for indoor air treatment and water purification,while large-pore IOs with the highest photon flux enhancement enable solar-driven photocatalysis such as outdoor pollutant removal and hydrogen production.For all tested IO designs,the absorbed photon flux exceeds that of equivalent planar slabs,highlighting the advantage of photonic structuring for sustainable photocatalytic applications.
基金supported by the National Natural Science Foundation of China(Grant No.32271554)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011501)。
文摘Predator–prey interactions are fundamental to understanding ecosystem stability and biodiversity.In this study,we propose and analyze a stochastic predator–prey model that incorporates two critical ecological factors:prey refuge and harvesting.The model also integrates disease transmission within the predator population,adding an important layer of realism.Using rigorous mathematical techniques,we demonstrate the existence and uniqueness of a global positive solution,thereby confirming the model's biological feasibility.We further derive sufficient conditions for two key ecological scenarios:stochastic permanence,which ensures the sustained co-existence of prey and predators over time,and extinction,where one or both populations decline to zero.The interplay between prey refuge and harvesting is thoroughly examined to understand their combined impact on population dynamics.All theoretical results are validated by detailed numerical simulations,highlighting the applicability of the model to real-world ecological systems.From the simulation results,we observed that with an adequate level of prey refuge and predator harvesting,the susceptible predator and prey coexist with extensive oscillations,while the infected predator population was moving towards extinction.In addition,we have investigated the effect of disease transmission on system dynamics.Our results show that,as the transmission rate of disease increases,the susceptible predator approaches extinction,whereas,on the other hand,when it declines,the susceptible predator shows robust oscillations while the infected approaches extinction.In both cases,the prey population demonstrates robust stability due to the prey refuge.Our findings show that the management of harvesting and the prey refuge can be effective ecological tactics for disease control and species protection under stochastic environmental effects.
基金supported by the National Key Research and Development Program of China(No.2022YFC3702800)the National Natural Science Foundation of China(Nos.22366008,22406032)the Guizhou Provincial Basic Research Program(Natural Science)(No.ZK(2023)045).
文摘Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,could become a sustainable alternative.Sorption-based atmospheric water harvesting(SAWH)has emerged as an available solution,yet conventional desorption methods relying on energy-intensive electrical heating hinder its scalability.Herein,a photothermal hygroscopic sponge has been developed for solar-driven atmospheric water harvesting.The composites combine a malleable melamine sponge skeleton,lithium chloride as a hygroscopic agent,and hydrangea-like molybdenum disulfide as a photothermal component,forming a multiscale“pore-film”cross-linked structure by an eco-friendly immersion-freeze-drying method.The optimized sample achieves exceptional hygroscopic capacity(3.92 g/g at 90%RH)and freshwater production efficiency(87.77%),which is attributed to synergistic effects of porous skeleton based crosslinked structures and“pore-film”structures,and outstanding photothermal conversion efficiency of MoS2.The unique structure could stabilize LiCl to prevent leakage,increase mass transfer effectiveness of whole SWAH process,and enable flexibility for diverse applications.We carried out outdoor experiments to demonstrate a solar-driven water production rate of 4.22 L m^(-2) d^(-1) without external energy input.This work provides insights into sustainable freshwater generation and promotes green energy utilization in addressing global water scarcity.
基金supported by the Yunnan Provincial Philosophy and Social Science Planning Projectthe Yunnan Academy of Social Sciences。
文摘China and Laos are close neighbors with a long-standing friendship.Since the early 2000s,China has supported Laos'economic and social development through wide-ranging cooperation projects,all guided by the vision of a community with a shared future.As this vision takes deeper root,many aid projects have moved from blueprint to reality,delivering tangible benefits across towns and villages and improving the lives of ordinary Lao people while further strengthening bilateral ties.
基金Supported by the National Natural Science Foundation of China(Grant No.12161080).
文摘In this paper,the dynamics of a Leslie-Gower predator-prey model with weak nonlin-ear harvesting and prey-taxis is discussed.By comparing and analyzing the differences between ordinary differential systems and chemotaxis systems in the stability of equilibrium points,the influence mechanism of chemotaxis on the dynamic behavior of the system is deeply studied.Theoretical analysis shows that chemotaxis significantly changes the stability characteristics of the system,and the reliability of theoretical results is further verified by numerical simulation.
基金Project supported by the National Natural Science Foundation of China(Nos.12202262,12172127,12032015,and 12121002)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(No.2023QNRC001)the Hunan Province Science and Technology Innovation Program of China(Nos.2025JJ20012 and 2025RC4022)。
文摘The rapid advancement of wearable electronic devices has paved the way for a more intelligent and interconnected world.However,ensuring the sustainable energy supply for these devices remains a critical challenge,particularly for specialized populations and professionals in demanding environments,where a lack of power can pose life-threatening risks.Herein,we propose a mechanically intelligent biomechanical energy harvesting approach that adapts to complex human motion excitations,thereby improving the energy harvesting performance.Leveraging a mechanical intelligence mechanism,the energy harvester aligns with human physiological habits,selectively activating or deactivating as needed.The system can also adapt to excitations of varying directions,amplitudes,and frequencies.Furthermore,the string tension helps reduce the impact forces on the knee joint during foot strikes.A theoretical model for the biomechanical energy harvesting system is developed to describe its dynamic and electrical characteristics,and a prototype is fabricated and tested under diverse conditions.The experimental results are in good agreement with the simulation trends,validating the effectiveness of the theoretical model.A test subject running at 8 km/h for 90 seconds can successfully power a smartphone for 20 seconds,demonstrating the viability of self-powered applications.This mechanically intelligent biomechanical energy harvesting method holds a promising solution for the sustainable power supply for wearable electronic devices.
基金supported by the Open Foundation of Hainan International Joint Research Center of Marine Advanced Photoelectric Functional Materials(2025MAPFM01)Fundação para a Ciência e Tecnologia(FCT),Portugal,for the Centro de Química Estrutural,Institute of Molecular Sciences projects UIDB/00100。
文摘Triboelectric nanogenerators(TENGs)show promise for sustainable energy harvesting;however,their development faces challenges due to the limited performance of traditional polymers,such as PDMS and PTFE.This drives interest in metal-organic frameworks(MOFs),which offer high surface area,tunable porosity,and customizable chemical functionality that can help overcome these limitations.In this review,we thoroughly analyze the application of MOFs in TENGs by exploring structural design strategies,ligand modifications,and layer engineering,as well as assessing performance results from recent studies.We highlight essential findings indicating that electron-withdrawing groups,such as-NO_(2),-F,and-SO_(3)H,notably increase tribonegativity.Additionally,doping with conductive nanomaterials and employing machine learning approaches further boost power density.Finally,we propose that future advancements in this area should focus on addressing environmental sensitivity,mechanical brittleness,and synthesis complexity through molecular-level tailoring combined with scalable device engineering,ultimately paving the way for durable,high-efficiency MOF-based TENGs.
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.
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.
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.
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.
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”.
