The quality of planting materials is the foundation for productivity,longevity,and berry quality of perennial grapevines with a long lifespan.Manipulating the nursery light spectrum may speed up the production of heal...The quality of planting materials is the foundation for productivity,longevity,and berry quality of perennial grapevines with a long lifespan.Manipulating the nursery light spectrum may speed up the production of healthy and high-quality planting vines but the underlying mechanisms remain elusive.Herein,the effects of different monochromatic lights(green,blue,and red)on grapevine growth,leaf photosynthesis,whole-plant carbon allocation,and transcriptome reprograming were investigated with white light as control.Results showed that blue and red lights were favorable for plantlet growth in comparison with white light.Blue light repressed excessive growth,significantly increased the maximum net photosynthetic rate(Pn)of leaves by 39.58%and leaf specific weight by 38.29%.Red light increased the dry weight of the stem by 53.60%,the starch content of the leaf by 53.63%,and the sucrose content of the stem by 230%.Green light reduced all photosynthetic indexes of the grape plantlet.Photosynthetic photon flux density(PPFD)/Ci–Pn curves indicated that blue light affected photosynthetic rate depending on the light intensity and CO2 concentration.RNA-seq analysis of different organs(leaf,stem,and root)revealed a systematic transcriptome remodeling and VvCOP1(CONSTITUTIVELY PHOTOMORPHOGENIC 1),VvHY5(ELONGATED HYPOCOTYL5),VvHYH(HY5 HOMOLOG),VvELIP(early light-induced protein)and VvPIF3(PHYTOCHROME INTERACTING FACTOR 3)may play important roles in this shoot-to-root signaling.Furthermore,the correlation network between differential expression genes and physiological traits indicated that VvpsbS(photosystem II subunit S),Vvpsb28(photosystem II subunit 28),VvHYH,VvSUS4(sucrose synthase 4),and VvALDA(fructose-bisphosphate aldolase)were pertinent candidate genes in responses to different light qualities.Our results provide a foundation for optimizing the light recipe of grape plantlets and strengthen the understanding of light signaling and carbon metabolism under different monochromatic lights.展开更多
The metal-organic framework(MOF)derived Ni–Co–C–N composite alloys(NiCCZ)were“embedded”inside the carbon cloth(CC)strands as opposed to the popular idea of growing them upward to realize ultrastable energy storag...The metal-organic framework(MOF)derived Ni–Co–C–N composite alloys(NiCCZ)were“embedded”inside the carbon cloth(CC)strands as opposed to the popular idea of growing them upward to realize ultrastable energy storage and conversion application.The NiCCZ was then oxygen functionalized,facilitating the next step of stoichiometric sulfur anion diffusion during hydrothermal sulfurization,generating a flower-like metal hydroxysulfide structure(NiCCZOS)with strong partial implantation inside CC.Thus obtained NiCCZOS shows an excellent capacity when tested as a supercapacitor electrode in a three-electrode configuration.Moreover,when paired with the biomass-derived nitrogen-rich activated carbon,the asymmetric supercapacitor device shows almost 100%capacity retention even after 45,000 charge–discharge cycles with remarkable energy density(59.4 Wh kg^(-1)/263.8μWh cm^(–2))owing to a uniquely designed cathode.Furthermore,the same electrode performed as an excellent bifunctional water-splitting electrocatalyst with an overpotential of 271 mV for oxygen evolution reaction(OER)and 168.4 mV for hydrogen evolution reaction(HER)at 10 mA cm−2 current density along with 30 h of unhinged chronopotentiometric stability performance for both HER and OER.Hence,a unique metal chalcogenide composite electrode/substrate configuration has been proposed as a highly stable electrode material for flexible energy storage and conversion applications.展开更多
The strength development law of γ-type dicalcium silicate (γ-C_(2)S) under different carbonation processes was investigated,and the carbonation mechanism of γ-C_(2)S under the action of NH_(4)HCO_(3) was clarified ...The strength development law of γ-type dicalcium silicate (γ-C_(2)S) under different carbonation processes was investigated,and the carbonation mechanism of γ-C_(2)S under the action of NH_(4)HCO_(3) was clarified by using a wide range of test methods,including XRD and SEM.A method of saturated NH_(4)HCO_(3) solution as a curing agent was identified to improve the carbonation efficiency and enhance the carbonation degree of γ-C_(2)S,and then a high-strength carbonated specimen was obtained.Microhardness analysis and SEM morphology analysis were conducted on the carbonised specimens obtained under atmospheric pressure carbonisation conditions using the curing agent.It was found that γ-C_(2)S could perform carbonisation well under atmospheric pressure,which promoted the carbonisation efficiency and decreased the carbonisation cost simultaneously.Therefore,a new carbonisation process solution was proposed for the rapid carbonisation of γ-C_(2)S.展开更多
Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important task.This study took China as the research ob...Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important task.This study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary structure.The results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption pattern.The dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality one.During the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing trend.The per capita food carbon emissions of residents in urban and rural showed an overall upward trend.The total food carbon emissions in urban increased significantly,while that in rural increased first and then decreased.The influence of beef and mutton on carbon emissions is the highest in dietary structure.Compared with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.展开更多
To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put fo...To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put forward.The carbonation effect of modified recycled coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recycled coarse aggregate were measured.Combined with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recycled coarse aggregate was revealed.The experimental results show that,compared with the non-carbonated recycled coarse aggregate,the physical and microscopic properties of carbonated recycled coarse aggregate are improved.The method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recycled coarse aggregate,for modified recycled coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 nm.The high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(OH)_(2) of the old mortar with nano-scale C-S-H,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized carbonation.It is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recycled coarse aggregate.展开更多
Understanding the spatial variation,temporal changes,and their underlying driving forces of carbon sequestration in various forests is of great importance for understanding the carbon cycle and carbon management optio...Understanding the spatial variation,temporal changes,and their underlying driving forces of carbon sequestration in various forests is of great importance for understanding the carbon cycle and carbon management options.How carbon density and sequestration in various Cunninghamia lanceolata forests,extensively cultivated for timber production in subtropical China,vary with biodiversity,forest structure,environment,and cultural factors remain poorly explored,presenting a critical knowledge gap for realizing carbon sequestration supply potential through management.Based on a large-scale database of 449 permanent forest inventory plots,we quantified the spatial-temporal heterogeneity of aboveground carbon densities and carbon accumulation rates in Cunninghamia lanceolate forests in Hunan Province,China,and attributed the contributions of stand structure,environmental,and management factors to the heterogeneity using quantile age-sequence analysis,partial least squares path modeling(PLS-PM),and hot-spot analysis.The results showed lower values of carbon density and sequestration on average,in comparison with other forests in the same climate zone(i.e.,subtropics),with pronounced spatial and temporal variability.Specifically,quantile regression analysis using carbon accumulation rates along an age sequence showed large differences in carbon sequestration rates among underperformed and outperformed forests(0.50 and 1.80 Mg·ha^(-1)·yr^(-1)).PLS-PM demonstrated that maximum DBH and stand density were the main crucial drivers of aboveground carbon density from young to mature forests.Furthermore,species diversity and geotopographic factors were the significant factors causing the large discrepancy in aboveground carbon density change between low-and high-carbon-bearing forests.Hotspot analysis revealed the importance of culture attributes in shaping the geospatial patterns of carbon sequestration.Our work highlighted that retaining largesized DBH trees and increasing shade-tolerant tree species were important to enhance carbon sequestration in C.lanceolate forests.展开更多
Users and edge servers are not fullymutually trusted inmobile edge computing(MEC),and hence blockchain can be introduced to provide trustableMEC.In blockchain-basedMEC,each edge server functions as a node in bothMEC a...Users and edge servers are not fullymutually trusted inmobile edge computing(MEC),and hence blockchain can be introduced to provide trustableMEC.In blockchain-basedMEC,each edge server functions as a node in bothMEC and blockchain,processing users’tasks and then uploading the task related information to the blockchain.That is,each edge server runs both users’offloaded tasks and blockchain tasks simultaneously.Note that there is a trade-off between the resource allocation for MEC and blockchain tasks.Therefore,the allocation of the resources of edge servers to the blockchain and theMEC is crucial for the processing delay of blockchain-based MEC.Most of the existing research tackles the problem of resource allocation in either blockchain or MEC,which leads to unfavorable performance of the blockchain-based MEC system.In this paper,we study how to allocate the computing resources of edge servers to the MEC and blockchain tasks with the aimtominimize the total systemprocessing delay.For the problem,we propose a computing resource Allocation algorithmfor Blockchain-based MEC(ABM)which utilizes the Slater’s condition,Karush-Kuhn-Tucker(KKT)conditions,partial derivatives of the Lagrangian function and subgradient projection method to obtain the solution.Simulation results show that ABM converges and effectively reduces the processing delay of blockchain-based MEC.展开更多
With the rapid development of Network Function Virtualization(NFV),the problem of low resource utilizationin traditional data centers is gradually being addressed.However,existing research does not optimize both local...With the rapid development of Network Function Virtualization(NFV),the problem of low resource utilizationin traditional data centers is gradually being addressed.However,existing research does not optimize both localand global allocation of resources in data centers.Hence,we propose an adaptive hybrid optimization strategy thatcombines dynamic programming and neural networks to improve resource utilization and service quality in datacenters.Our approach encompasses a service function chain simulation generator,a parallel architecture servicesystem,a dynamic programming strategy formaximizing the utilization of local server resources,a neural networkfor predicting the global utilization rate of resources and a global resource optimization strategy for bottleneck andredundant resources.With the implementation of our local and global resource allocation strategies,the systemperformance is significantly optimized through simulation.展开更多
The carbon tradingmarket can promote“carbon peaking”and“carbon neutrality”at low cost,but carbon emission quotas face attacks such as data forgery,tampering,counterfeiting,and replay in the electricity trading mar...The carbon tradingmarket can promote“carbon peaking”and“carbon neutrality”at low cost,but carbon emission quotas face attacks such as data forgery,tampering,counterfeiting,and replay in the electricity trading market.Certificateless signatures are a new cryptographic technology that can address traditional cryptography’s general essential certificate requirements and avoid the problem of crucial escrowbased on identity cryptography.However,most certificateless signatures still suffer fromvarious security flaws.We present a secure and efficient certificateless signing scheme by examining the security of existing certificateless signature schemes.To ensure the integrity and verifiability of electricity carbon quota trading,we propose an electricity carbon quota trading scheme based on a certificateless signature and blockchain.Our scheme utilizes certificateless signatures to ensure the validity and nonrepudiation of transactions and adopts blockchain technology to achieve immutability and traceability in electricity carbon quota transactions.In addition,validating electricity carbon quota transactions does not require time-consuming bilinear pairing operations.The results of the analysis indicate that our scheme meets existential unforgeability under adaptive selective message attacks,offers conditional identity privacy protection,resists replay attacks,and demonstrates high computing and communication performance.展开更多
The steel industry is a major source of CO_(2) emissions,and thus,the mitigation of carbon emissions is the most pressing challenge in this sector.In this paper,international environmental governance in the steel indu...The steel industry is a major source of CO_(2) emissions,and thus,the mitigation of carbon emissions is the most pressing challenge in this sector.In this paper,international environmental governance in the steel industry is reviewed,and the current state of development of low-carbon technologies is discussed.Additionally,low-carbon pathways for the steel industry at the current time are proposed,emphasizing prevention and treatment strategies.Furthermore,the prospects of low-carbon technologies are explored from the perspective of transitioning the energy structure to a“carbon-electricity-hydrogen”relationship.Overall,steel enterprises should adopt hydrogen-rich metallurgical technologies that are compatible with current needs and process flows in the short term,based on the carbon substitution with hydrogen(prevention)and the CCU(CO_(2) capture and utilization)concepts(treatment).Additionally,the capture and utilization of CO_(2) for steelmaking,which can assist in achieving short-term emission reduction targets but is not a long-term solution,is discussed.In conclusion,in the long term,the carbon metallurgical process should be gradually supplanted by a hydrogen-electric synergistic approach,thus transforming the energy structure of existing steelmaking processes and attaining near-zero carbon emission steelmaking technology.展开更多
A real-time adaptive roles allocation method based on reinforcement learning is proposed to improve humanrobot cooperation performance for a curtain wall installation task.This method breaks the traditional idea that ...A real-time adaptive roles allocation method based on reinforcement learning is proposed to improve humanrobot cooperation performance for a curtain wall installation task.This method breaks the traditional idea that the robot is regarded as the follower or only adjusts the leader and the follower in cooperation.In this paper,a self-learning method is proposed which can dynamically adapt and continuously adjust the initiative weight of the robot according to the change of the task.Firstly,the physical human-robot cooperation model,including the role factor is built.Then,a reinforcement learningmodel that can adjust the role factor in real time is established,and a reward and actionmodel is designed.The role factor can be adjusted continuously according to the comprehensive performance of the human-robot interaction force and the robot’s Jerk during the repeated installation.Finally,the roles adjustment rule established above continuously improves the comprehensive performance.Experiments of the dynamic roles allocation and the effect of the performance weighting coefficient on the result have been verified.The results show that the proposed method can realize the role adaptation and achieve the dual optimization goal of reducing the sum of the cooperator force and the robot’s Jerk.展开更多
The excessive use of nonrenewable energy has brought about serious greenhouse effect.Converting CO_(2) into high-value-added chemicals is undoubtedly the best choice to solve energy problems.Due to the excellent cost-...The excessive use of nonrenewable energy has brought about serious greenhouse effect.Converting CO_(2) into high-value-added chemicals is undoubtedly the best choice to solve energy problems.Due to the excellent cost-effectiveness and dramatic catalytic performance,nickel-based catalysts have been considered as the most promising candidates for the electrocatalytic CO_(2) reduction reaction(eCO_(2)RR).In this work,the electrocatalytic reduction mechanism of CO_(2) over Ni-based materials is reviewed.The strategies to improve the eCO_(2)RR performance are emphasized.Moreover,the research on Ni-based materials for syngas generation is briefly summarized.Finally,the prospects of nickel-based materials in the eCO_(2)RR are provided with the hope of improving transition-metal-based electrocatalysts for eCO_(2)RR in the future.展开更多
Two-dimensional carbon/carbon(2D C/C)composites are a special class of carbon/carbon composites,generally obtained by combining resin-impregnated carbon fiber clothes,which are then cured and carbonized.This study dea...Two-dimensional carbon/carbon(2D C/C)composites are a special class of carbon/carbon composites,generally obtained by combining resin-impregnated carbon fiber clothes,which are then cured and carbonized.This study deals with the preparation of a protective coating for these materials.This coating,based on graphite,was prepared by the slurry method.The effect of graphite and phenolic resin powders with different weight ratios was examined.The results have shown that the coating slurry can fill the pores and cracks of the composite surface,thereby densifying the surface layer of the material.With the increase of the graphite powder/phenolic resin weight ratio,the coating density is enhanced while the coating surface flatness decreases;moreover,the protective ability of coating against erosion first increases(from 1:3 to 2:2)and then decreases(from 2:2 to 3:1).When the weight ratio is about 1:1,the coating for 2D C/C composites exhibits the best erosion resistance,which greatly aids these materials during gas quenching.In this case,the erosion rate is decreased by approximately 41.5%at the impact angle of 30°and 52.3%at normal impact,respectively.This can be attributed to the ability of the coating slurry to infiltrate into the substrate,thereby bonding the fibers together and increasing the compactness of the 2D C/C composites.展开更多
Collaborative edge computing is a promising direction to handle the computation intensive tasks in B5G wireless networks.However,edge computing servers(ECSs)from different operators may not trust each other,and thus t...Collaborative edge computing is a promising direction to handle the computation intensive tasks in B5G wireless networks.However,edge computing servers(ECSs)from different operators may not trust each other,and thus the incentives for collaboration cannot be guaranteed.In this paper,we propose a consortium blockchain enabled collaborative edge computing framework,where users can offload computing tasks to ECSs from different operators.To minimize the total delay of users,we formulate a joint task offloading and resource optimization problem,under the constraint of the computing capability of each ECS.We apply the Tammer decomposition method and heuristic optimization algorithms to obtain the optimal solution.Finally,we propose a reputation based node selection approach to facilitate the consensus process,and also consider a completion time based primary node selection to avoid monopolization of certain edge node and enhance the security of the blockchain.Simulation results validate the effectiveness of the proposed algorithm,and the total delay can be reduced by up to 40%compared with the non-cooperative case.展开更多
The accessibility of tetracycline resistance gene (tetG) into the pores of activated carbon (AC), as well as the impact of the pore size distribution (PSD) of AC on the uptake capacity of tetG, were investigated using...The accessibility of tetracycline resistance gene (tetG) into the pores of activated carbon (AC), as well as the impact of the pore size distribution (PSD) of AC on the uptake capacity of tetG, were investigated using eight types of AC (four coal-based and four wood-based). AC showed the capability to admit tetG and the average reduction of tetG for coal-based and wood-based ACs at the AC dose of 1 g·L<sup>-1</sup> was 3.12 log and 3.65 log, respectively. The uptake kinetic analysis showed that the uptake of the gene followed the pseudo-second-order kinetics reaction, and the uptake rate constant for the coal-based and wood-based ACs was in the range of 5.97 × 10<sup>-12</sup> - 4.64 × 10<sup>-9</sup> and 7.02 × 10<sup>-11</sup> - 1.59 × 10<sup>-8</sup> copies·mg<sup>-1</sup>·min<sup>-1</sup>, respectively. The uptake capacity analysis by fitting the obtained experiment data with the Freundlich isotherm model indicated that the uptake constant (K<sub>F</sub>) values were 1.71 × 10<sup>3</sup> - 8.00 × 10<sup>9</sup> (copies·g<sup>-1</sup>)<sup>1-1/n</sup> for coal-based ACs and 7.00 × 10<sup>8</sup> - 3.00 × 10<sup>10</sup> (copies·g<sup>-1</sup>)<sup>1-1/n</sup> for wood-based ones. In addition, the correlation analysis between K<sub>F</sub> values and pore volume as well as pore surface at different pore size regions of ACs showed that relatively higher positive correlation was found for pores of 50 - 100 Å, suggesting ACs with more pores in this size region can uptake more tetG. The findings of this study are valuable as reference for optimizing the adsorption process regarding antibiotic resistance-related concerns in drinking water treatment.展开更多
Cobalt sulphides attract much attention as anode materials for Li-ion batteries(LIBs).However,its poor conductivity,low initial column efficiency and large volume changes during cycling have hindered its further devel...Cobalt sulphides attract much attention as anode materials for Li-ion batteries(LIBs).However,its poor conductivity,low initial column efficiency and large volume changes during cycling have hindered its further development.Herein,novel interlaced CoS nanosheets were firstly prepared on Carbon Fiber Cloth(CFC)by two hydrothermal reactions followed with carbon coating via carbonizing dopamine(CoS NS@C/CFC).As a freestanding anode,the nanosheet structure of CoS not only accommodates the volume variation,but also provides a large interface area to proceed the charge transfer reaction.In addition,CFC works as both a three-dimensional skeleton and an active substance which can further improve the areal capacity of the resulting electrode.Furthermore,the coated carbon combined with the CFC work as a 3D conductive network to facilitate the electron conduction.The obtained CoS NS@C/CFC,and the contrast sample prepared with the same procedure but without carbon coating(CoS NS/CFC),are characterized with XRD,SEM,TEM,XPS and electrochemical measurements.The results show that the CoS NS@C/CFC possesses much improved electrochemical performance due to the synergistic effect of nanosheet CoS,the coated carbon and the CFC substrate,exhibiting high initial columbic efficiency(~87%),high areal capacity(2.5 at 0.15 mA cm−2),excellent rate performance(1.6 at 2.73 mA cm−2)and improved cycle stability(87.5%capacity retention after 300 cycles).This work may provide a new route to explore freestanding anodes with high areal specific capacity for LIBs.展开更多
In this paper,we optimize the spectrum efficiency(SE)of uplink massive multiple-input multiple-output(MIMO)system with imperfect channel state information(CSI)over Rayleigh fading channel.The SE optimization problem i...In this paper,we optimize the spectrum efficiency(SE)of uplink massive multiple-input multiple-output(MIMO)system with imperfect channel state information(CSI)over Rayleigh fading channel.The SE optimization problem is formulated under the constraints of maximum power and minimum rate of each user.Then,we develop a near-optimal power allocation(PA)scheme by using the successive convex approximation(SCA)method,Lagrange multiplier method,and block coordinate descent(BCD)method,and it can obtain almost the same SE as the benchmark scheme with lower complexity.Since this scheme needs three-layer iteration,a suboptimal PA scheme is developed to further reduce the complexity,where the characteristic of massive MIMO(i.e.,numerous receive antennas)is utilized for convex reformulation,and the rate constraint is converted to linear constraints.This suboptimal scheme only needs single-layer iteration,thus has lower complexity than the near-optimal scheme.Finally,we joint design the pilot power and data power to further improve the performance,and propose an two-stage algorithm to obtain joint PA.Simulation results verify the effectiveness of the proposed schemes,and superior SE performance is achieved.展开更多
Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the ...Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.展开更多
Quantum key distribution(QKD)is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols.However,due to the stringent requirements of the quantum key generation env...Quantum key distribution(QKD)is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols.However,due to the stringent requirements of the quantum key generation environment,the generated quantum keys are considered valuable,and the slow key generation rate conflicts with the high-speed data transmission in traditional optical networks.In this paper,for the QKD network with a trusted relay,which is mainly based on point-to-point quantum keys and has complex changes in network resources,we aim to allocate resources reasonably for data packet distribution.Firstly,we formulate a linear programming constraint model for the key resource allocation(KRA)problem based on the time-slot scheduling.Secondly,we propose a new scheduling scheme based on the graded key security requirements(GKSR)and a new micro-log key storage algorithm for effective storage and management of key resources.Finally,we propose a key resource consumption(KRC)routing optimization algorithm to properly allocate time slots,routes,and key resources.Simulation results show that the proposed scheme significantly improves the key distribution success rate and key resource utilization rate,among others.展开更多
Mobile edge computing(MEC)-enabled satellite-terrestrial networks(STNs)can provide Internet of Things(IoT)devices with global computing services.Sometimes,the network state information is uncertain or unknown.To deal ...Mobile edge computing(MEC)-enabled satellite-terrestrial networks(STNs)can provide Internet of Things(IoT)devices with global computing services.Sometimes,the network state information is uncertain or unknown.To deal with this situation,we investigate online learning-based offloading decision and resource allocation in MEC-enabled STNs in this paper.The problem of minimizing the average sum task completion delay of all IoT devices over all time periods is formulated.We decompose this optimization problem into a task offloading decision problem and a computing resource allocation problem.A joint optimization scheme of offloading decision and resource allocation is then proposed,which consists of a task offloading decision algorithm based on the devices cooperation aided upper confidence bound(UCB)algorithm and a computing resource allocation algorithm based on the Lagrange multiplier method.Simulation results validate that the proposed scheme performs better than other baseline schemes.展开更多
基金supported by National Natural Science Foundation of China(U20A2041)the National Key R&D Program of China(2019YFD1000100,2021YFE0109500)+1 种基金the Agricultural Breeding Project of Ningxia Hui Autonomous Region(NXNYYZ202101)the CAS Youth Interdisciplinary Team(JCTD-2022-06).
文摘The quality of planting materials is the foundation for productivity,longevity,and berry quality of perennial grapevines with a long lifespan.Manipulating the nursery light spectrum may speed up the production of healthy and high-quality planting vines but the underlying mechanisms remain elusive.Herein,the effects of different monochromatic lights(green,blue,and red)on grapevine growth,leaf photosynthesis,whole-plant carbon allocation,and transcriptome reprograming were investigated with white light as control.Results showed that blue and red lights were favorable for plantlet growth in comparison with white light.Blue light repressed excessive growth,significantly increased the maximum net photosynthetic rate(Pn)of leaves by 39.58%and leaf specific weight by 38.29%.Red light increased the dry weight of the stem by 53.60%,the starch content of the leaf by 53.63%,and the sucrose content of the stem by 230%.Green light reduced all photosynthetic indexes of the grape plantlet.Photosynthetic photon flux density(PPFD)/Ci–Pn curves indicated that blue light affected photosynthetic rate depending on the light intensity and CO2 concentration.RNA-seq analysis of different organs(leaf,stem,and root)revealed a systematic transcriptome remodeling and VvCOP1(CONSTITUTIVELY PHOTOMORPHOGENIC 1),VvHY5(ELONGATED HYPOCOTYL5),VvHYH(HY5 HOMOLOG),VvELIP(early light-induced protein)and VvPIF3(PHYTOCHROME INTERACTING FACTOR 3)may play important roles in this shoot-to-root signaling.Furthermore,the correlation network between differential expression genes and physiological traits indicated that VvpsbS(photosystem II subunit S),Vvpsb28(photosystem II subunit 28),VvHYH,VvSUS4(sucrose synthase 4),and VvALDA(fructose-bisphosphate aldolase)were pertinent candidate genes in responses to different light qualities.Our results provide a foundation for optimizing the light recipe of grape plantlets and strengthen the understanding of light signaling and carbon metabolism under different monochromatic lights.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(2021R1A4A2000934).
文摘The metal-organic framework(MOF)derived Ni–Co–C–N composite alloys(NiCCZ)were“embedded”inside the carbon cloth(CC)strands as opposed to the popular idea of growing them upward to realize ultrastable energy storage and conversion application.The NiCCZ was then oxygen functionalized,facilitating the next step of stoichiometric sulfur anion diffusion during hydrothermal sulfurization,generating a flower-like metal hydroxysulfide structure(NiCCZOS)with strong partial implantation inside CC.Thus obtained NiCCZOS shows an excellent capacity when tested as a supercapacitor electrode in a three-electrode configuration.Moreover,when paired with the biomass-derived nitrogen-rich activated carbon,the asymmetric supercapacitor device shows almost 100%capacity retention even after 45,000 charge–discharge cycles with remarkable energy density(59.4 Wh kg^(-1)/263.8μWh cm^(–2))owing to a uniquely designed cathode.Furthermore,the same electrode performed as an excellent bifunctional water-splitting electrocatalyst with an overpotential of 271 mV for oxygen evolution reaction(OER)and 168.4 mV for hydrogen evolution reaction(HER)at 10 mA cm−2 current density along with 30 h of unhinged chronopotentiometric stability performance for both HER and OER.Hence,a unique metal chalcogenide composite electrode/substrate configuration has been proposed as a highly stable electrode material for flexible energy storage and conversion applications.
基金Funded by Hubei Technology Innovation Key Program (No.2018AAA004)。
文摘The strength development law of γ-type dicalcium silicate (γ-C_(2)S) under different carbonation processes was investigated,and the carbonation mechanism of γ-C_(2)S under the action of NH_(4)HCO_(3) was clarified by using a wide range of test methods,including XRD and SEM.A method of saturated NH_(4)HCO_(3) solution as a curing agent was identified to improve the carbonation efficiency and enhance the carbonation degree of γ-C_(2)S,and then a high-strength carbonated specimen was obtained.Microhardness analysis and SEM morphology analysis were conducted on the carbonised specimens obtained under atmospheric pressure carbonisation conditions using the curing agent.It was found that γ-C_(2)S could perform carbonisation well under atmospheric pressure,which promoted the carbonisation efficiency and decreased the carbonisation cost simultaneously.Therefore,a new carbonisation process solution was proposed for the rapid carbonisation of γ-C_(2)S.
基金Under the auspices of National Natural Science Foundation of China(No.42171230)。
文摘Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important task.This study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary structure.The results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption pattern.The dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality one.During the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing trend.The per capita food carbon emissions of residents in urban and rural showed an overall upward trend.The total food carbon emissions in urban increased significantly,while that in rural increased first and then decreased.The influence of beef and mutton on carbon emissions is the highest in dietary structure.Compared with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.
基金Funded by Joint Funds of the National Natural Science Foundation of China(No.U1904188)the Jiangxi Provincial Department of Education Science and Technology Project(Nos.GJJ171079,GJJ181023,and GJJ181022)。
文摘To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put forward.The carbonation effect of modified recycled coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recycled coarse aggregate were measured.Combined with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recycled coarse aggregate was revealed.The experimental results show that,compared with the non-carbonated recycled coarse aggregate,the physical and microscopic properties of carbonated recycled coarse aggregate are improved.The method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recycled coarse aggregate,for modified recycled coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 nm.The high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(OH)_(2) of the old mortar with nano-scale C-S-H,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized carbonation.It is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recycled coarse aggregate.
基金the National Natural Science Foundation of China(Nos.U20A2089 and 41971152)the Research Foundation of the Department of Natural Resources of Hunan Province(No.20230138ST)to SLthe open research fund of Technology Innovation Center for Ecological Conservation and Restoration in Dongting Lake Basin,Ministry of Natural Resources(No.2023005)to YZ。
文摘Understanding the spatial variation,temporal changes,and their underlying driving forces of carbon sequestration in various forests is of great importance for understanding the carbon cycle and carbon management options.How carbon density and sequestration in various Cunninghamia lanceolata forests,extensively cultivated for timber production in subtropical China,vary with biodiversity,forest structure,environment,and cultural factors remain poorly explored,presenting a critical knowledge gap for realizing carbon sequestration supply potential through management.Based on a large-scale database of 449 permanent forest inventory plots,we quantified the spatial-temporal heterogeneity of aboveground carbon densities and carbon accumulation rates in Cunninghamia lanceolate forests in Hunan Province,China,and attributed the contributions of stand structure,environmental,and management factors to the heterogeneity using quantile age-sequence analysis,partial least squares path modeling(PLS-PM),and hot-spot analysis.The results showed lower values of carbon density and sequestration on average,in comparison with other forests in the same climate zone(i.e.,subtropics),with pronounced spatial and temporal variability.Specifically,quantile regression analysis using carbon accumulation rates along an age sequence showed large differences in carbon sequestration rates among underperformed and outperformed forests(0.50 and 1.80 Mg·ha^(-1)·yr^(-1)).PLS-PM demonstrated that maximum DBH and stand density were the main crucial drivers of aboveground carbon density from young to mature forests.Furthermore,species diversity and geotopographic factors were the significant factors causing the large discrepancy in aboveground carbon density change between low-and high-carbon-bearing forests.Hotspot analysis revealed the importance of culture attributes in shaping the geospatial patterns of carbon sequestration.Our work highlighted that retaining largesized DBH trees and increasing shade-tolerant tree species were important to enhance carbon sequestration in C.lanceolate forests.
基金supported by the Key Research and Development Project in Anhui Province of China(Grant No.202304a05020059)the Fundamental Research Funds for the Central Universities of China(Grant No.PA2023GDSK0055)the Project of Anhui Province Economic and Information Bureau(Grant No.JB20099).
文摘Users and edge servers are not fullymutually trusted inmobile edge computing(MEC),and hence blockchain can be introduced to provide trustableMEC.In blockchain-basedMEC,each edge server functions as a node in bothMEC and blockchain,processing users’tasks and then uploading the task related information to the blockchain.That is,each edge server runs both users’offloaded tasks and blockchain tasks simultaneously.Note that there is a trade-off between the resource allocation for MEC and blockchain tasks.Therefore,the allocation of the resources of edge servers to the blockchain and theMEC is crucial for the processing delay of blockchain-based MEC.Most of the existing research tackles the problem of resource allocation in either blockchain or MEC,which leads to unfavorable performance of the blockchain-based MEC system.In this paper,we study how to allocate the computing resources of edge servers to the MEC and blockchain tasks with the aimtominimize the total systemprocessing delay.For the problem,we propose a computing resource Allocation algorithmfor Blockchain-based MEC(ABM)which utilizes the Slater’s condition,Karush-Kuhn-Tucker(KKT)conditions,partial derivatives of the Lagrangian function and subgradient projection method to obtain the solution.Simulation results show that ABM converges and effectively reduces the processing delay of blockchain-based MEC.
基金the Fundamental Research Program of Guangdong,China,under Grants 2020B1515310023 and 2023A1515011281in part by the National Natural Science Foundation of China under Grant 61571005.
文摘With the rapid development of Network Function Virtualization(NFV),the problem of low resource utilizationin traditional data centers is gradually being addressed.However,existing research does not optimize both localand global allocation of resources in data centers.Hence,we propose an adaptive hybrid optimization strategy thatcombines dynamic programming and neural networks to improve resource utilization and service quality in datacenters.Our approach encompasses a service function chain simulation generator,a parallel architecture servicesystem,a dynamic programming strategy formaximizing the utilization of local server resources,a neural networkfor predicting the global utilization rate of resources and a global resource optimization strategy for bottleneck andredundant resources.With the implementation of our local and global resource allocation strategies,the systemperformance is significantly optimized through simulation.
基金the National Fund Project No.62172337National Natural Science Foundation of China(No.61662069)China Postdoctoral Science Foundation(No.2017M610817).
文摘The carbon tradingmarket can promote“carbon peaking”and“carbon neutrality”at low cost,but carbon emission quotas face attacks such as data forgery,tampering,counterfeiting,and replay in the electricity trading market.Certificateless signatures are a new cryptographic technology that can address traditional cryptography’s general essential certificate requirements and avoid the problem of crucial escrowbased on identity cryptography.However,most certificateless signatures still suffer fromvarious security flaws.We present a secure and efficient certificateless signing scheme by examining the security of existing certificateless signature schemes.To ensure the integrity and verifiability of electricity carbon quota trading,we propose an electricity carbon quota trading scheme based on a certificateless signature and blockchain.Our scheme utilizes certificateless signatures to ensure the validity and nonrepudiation of transactions and adopts blockchain technology to achieve immutability and traceability in electricity carbon quota transactions.In addition,validating electricity carbon quota transactions does not require time-consuming bilinear pairing operations.The results of the analysis indicate that our scheme meets existential unforgeability under adaptive selective message attacks,offers conditional identity privacy protection,resists replay attacks,and demonstrates high computing and communication performance.
文摘The steel industry is a major source of CO_(2) emissions,and thus,the mitigation of carbon emissions is the most pressing challenge in this sector.In this paper,international environmental governance in the steel industry is reviewed,and the current state of development of low-carbon technologies is discussed.Additionally,low-carbon pathways for the steel industry at the current time are proposed,emphasizing prevention and treatment strategies.Furthermore,the prospects of low-carbon technologies are explored from the perspective of transitioning the energy structure to a“carbon-electricity-hydrogen”relationship.Overall,steel enterprises should adopt hydrogen-rich metallurgical technologies that are compatible with current needs and process flows in the short term,based on the carbon substitution with hydrogen(prevention)and the CCU(CO_(2) capture and utilization)concepts(treatment).Additionally,the capture and utilization of CO_(2) for steelmaking,which can assist in achieving short-term emission reduction targets but is not a long-term solution,is discussed.In conclusion,in the long term,the carbon metallurgical process should be gradually supplanted by a hydrogen-electric synergistic approach,thus transforming the energy structure of existing steelmaking processes and attaining near-zero carbon emission steelmaking technology.
基金The research has been generously supported by Tianjin Education Commission Scientific Research Program(2020KJ056),ChinaTianjin Science and Technology Planning Project(22YDTPJC00970),China.The authors would like to express their sincere appreciation for all support provided.
文摘A real-time adaptive roles allocation method based on reinforcement learning is proposed to improve humanrobot cooperation performance for a curtain wall installation task.This method breaks the traditional idea that the robot is regarded as the follower or only adjusts the leader and the follower in cooperation.In this paper,a self-learning method is proposed which can dynamically adapt and continuously adjust the initiative weight of the robot according to the change of the task.Firstly,the physical human-robot cooperation model,including the role factor is built.Then,a reinforcement learningmodel that can adjust the role factor in real time is established,and a reward and actionmodel is designed.The role factor can be adjusted continuously according to the comprehensive performance of the human-robot interaction force and the robot’s Jerk during the repeated installation.Finally,the roles adjustment rule established above continuously improves the comprehensive performance.Experiments of the dynamic roles allocation and the effect of the performance weighting coefficient on the result have been verified.The results show that the proposed method can realize the role adaptation and achieve the dual optimization goal of reducing the sum of the cooperator force and the robot’s Jerk.
基金support from the National Natural Science Foundation of China(52072389,52311530113)the Science and Technology Commission of Shanghai Municipality(22DZ1205600,20520760900)+2 种基金the Program of Shanghai Academic Research Leader(20XD1424300)for financial support.The authors also would like to express their gratitude to Tangshan Basic Research Funding Projects(23130210E),Hebei Province High-level Talent(Postdoctor)Funding Project(B2022003025)Key R&D projects of North China University of Science and Technology(ZD-ST-202301)Tangshan Talent Funding Project(A202202007)for their financial support.
文摘The excessive use of nonrenewable energy has brought about serious greenhouse effect.Converting CO_(2) into high-value-added chemicals is undoubtedly the best choice to solve energy problems.Due to the excellent cost-effectiveness and dramatic catalytic performance,nickel-based catalysts have been considered as the most promising candidates for the electrocatalytic CO_(2) reduction reaction(eCO_(2)RR).In this work,the electrocatalytic reduction mechanism of CO_(2) over Ni-based materials is reviewed.The strategies to improve the eCO_(2)RR performance are emphasized.Moreover,the research on Ni-based materials for syngas generation is briefly summarized.Finally,the prospects of nickel-based materials in the eCO_(2)RR are provided with the hope of improving transition-metal-based electrocatalysts for eCO_(2)RR in the future.
基金This paper has obtained the support of the National Natural Science Foundation of China(No.51902039)High-Level Talents Innovation Support Plan of Dalian(No.2020RQ127)Scientific Research Project of Liaoning Provincial Department Education(No.LJKZ0722)。
文摘Two-dimensional carbon/carbon(2D C/C)composites are a special class of carbon/carbon composites,generally obtained by combining resin-impregnated carbon fiber clothes,which are then cured and carbonized.This study deals with the preparation of a protective coating for these materials.This coating,based on graphite,was prepared by the slurry method.The effect of graphite and phenolic resin powders with different weight ratios was examined.The results have shown that the coating slurry can fill the pores and cracks of the composite surface,thereby densifying the surface layer of the material.With the increase of the graphite powder/phenolic resin weight ratio,the coating density is enhanced while the coating surface flatness decreases;moreover,the protective ability of coating against erosion first increases(from 1:3 to 2:2)and then decreases(from 2:2 to 3:1).When the weight ratio is about 1:1,the coating for 2D C/C composites exhibits the best erosion resistance,which greatly aids these materials during gas quenching.In this case,the erosion rate is decreased by approximately 41.5%at the impact angle of 30°and 52.3%at normal impact,respectively.This can be attributed to the ability of the coating slurry to infiltrate into the substrate,thereby bonding the fibers together and increasing the compactness of the 2D C/C composites.
基金supported in part by the National Key R&D Program of China under Grant 2020YFB1005900the National Natural Science Foundation of China under Grant 62001220+3 种基金the Jiangsu Provincial Key Research and Development Program under Grants BE2022068the Natural Science Foundation of Jiangsu Province under Grants BK20200440the Future Network Scientific Research Fund Project FNSRFP-2021-YB-03the Young Elite Scientist Sponsorship Program,China Association for Science and Technology.
文摘Collaborative edge computing is a promising direction to handle the computation intensive tasks in B5G wireless networks.However,edge computing servers(ECSs)from different operators may not trust each other,and thus the incentives for collaboration cannot be guaranteed.In this paper,we propose a consortium blockchain enabled collaborative edge computing framework,where users can offload computing tasks to ECSs from different operators.To minimize the total delay of users,we formulate a joint task offloading and resource optimization problem,under the constraint of the computing capability of each ECS.We apply the Tammer decomposition method and heuristic optimization algorithms to obtain the optimal solution.Finally,we propose a reputation based node selection approach to facilitate the consensus process,and also consider a completion time based primary node selection to avoid monopolization of certain edge node and enhance the security of the blockchain.Simulation results validate the effectiveness of the proposed algorithm,and the total delay can be reduced by up to 40%compared with the non-cooperative case.
文摘The accessibility of tetracycline resistance gene (tetG) into the pores of activated carbon (AC), as well as the impact of the pore size distribution (PSD) of AC on the uptake capacity of tetG, were investigated using eight types of AC (four coal-based and four wood-based). AC showed the capability to admit tetG and the average reduction of tetG for coal-based and wood-based ACs at the AC dose of 1 g·L<sup>-1</sup> was 3.12 log and 3.65 log, respectively. The uptake kinetic analysis showed that the uptake of the gene followed the pseudo-second-order kinetics reaction, and the uptake rate constant for the coal-based and wood-based ACs was in the range of 5.97 × 10<sup>-12</sup> - 4.64 × 10<sup>-9</sup> and 7.02 × 10<sup>-11</sup> - 1.59 × 10<sup>-8</sup> copies·mg<sup>-1</sup>·min<sup>-1</sup>, respectively. The uptake capacity analysis by fitting the obtained experiment data with the Freundlich isotherm model indicated that the uptake constant (K<sub>F</sub>) values were 1.71 × 10<sup>3</sup> - 8.00 × 10<sup>9</sup> (copies·g<sup>-1</sup>)<sup>1-1/n</sup> for coal-based ACs and 7.00 × 10<sup>8</sup> - 3.00 × 10<sup>10</sup> (copies·g<sup>-1</sup>)<sup>1-1/n</sup> for wood-based ones. In addition, the correlation analysis between K<sub>F</sub> values and pore volume as well as pore surface at different pore size regions of ACs showed that relatively higher positive correlation was found for pores of 50 - 100 Å, suggesting ACs with more pores in this size region can uptake more tetG. The findings of this study are valuable as reference for optimizing the adsorption process regarding antibiotic resistance-related concerns in drinking water treatment.
基金supported by the National Natural Science Foundation of China (Grant Nos.21573109,21206069)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
文摘Cobalt sulphides attract much attention as anode materials for Li-ion batteries(LIBs).However,its poor conductivity,low initial column efficiency and large volume changes during cycling have hindered its further development.Herein,novel interlaced CoS nanosheets were firstly prepared on Carbon Fiber Cloth(CFC)by two hydrothermal reactions followed with carbon coating via carbonizing dopamine(CoS NS@C/CFC).As a freestanding anode,the nanosheet structure of CoS not only accommodates the volume variation,but also provides a large interface area to proceed the charge transfer reaction.In addition,CFC works as both a three-dimensional skeleton and an active substance which can further improve the areal capacity of the resulting electrode.Furthermore,the coated carbon combined with the CFC work as a 3D conductive network to facilitate the electron conduction.The obtained CoS NS@C/CFC,and the contrast sample prepared with the same procedure but without carbon coating(CoS NS/CFC),are characterized with XRD,SEM,TEM,XPS and electrochemical measurements.The results show that the CoS NS@C/CFC possesses much improved electrochemical performance due to the synergistic effect of nanosheet CoS,the coated carbon and the CFC substrate,exhibiting high initial columbic efficiency(~87%),high areal capacity(2.5 at 0.15 mA cm−2),excellent rate performance(1.6 at 2.73 mA cm−2)and improved cycle stability(87.5%capacity retention after 300 cycles).This work may provide a new route to explore freestanding anodes with high areal specific capacity for LIBs.
基金supported by the Fundamental Research Funds for the Central Universities of NUAA(No.kfjj20200414)Natural Science Foundation of Jiangsu Province in China(No.BK20181289).
文摘In this paper,we optimize the spectrum efficiency(SE)of uplink massive multiple-input multiple-output(MIMO)system with imperfect channel state information(CSI)over Rayleigh fading channel.The SE optimization problem is formulated under the constraints of maximum power and minimum rate of each user.Then,we develop a near-optimal power allocation(PA)scheme by using the successive convex approximation(SCA)method,Lagrange multiplier method,and block coordinate descent(BCD)method,and it can obtain almost the same SE as the benchmark scheme with lower complexity.Since this scheme needs three-layer iteration,a suboptimal PA scheme is developed to further reduce the complexity,where the characteristic of massive MIMO(i.e.,numerous receive antennas)is utilized for convex reformulation,and the rate constraint is converted to linear constraints.This suboptimal scheme only needs single-layer iteration,thus has lower complexity than the near-optimal scheme.Finally,we joint design the pilot power and data power to further improve the performance,and propose an two-stage algorithm to obtain joint PA.Simulation results verify the effectiveness of the proposed schemes,and superior SE performance is achieved.
文摘Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.
基金Project supported by the Natural Science Foundation of Jilin Province of China(Grant No.20210101417JC).
文摘Quantum key distribution(QKD)is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols.However,due to the stringent requirements of the quantum key generation environment,the generated quantum keys are considered valuable,and the slow key generation rate conflicts with the high-speed data transmission in traditional optical networks.In this paper,for the QKD network with a trusted relay,which is mainly based on point-to-point quantum keys and has complex changes in network resources,we aim to allocate resources reasonably for data packet distribution.Firstly,we formulate a linear programming constraint model for the key resource allocation(KRA)problem based on the time-slot scheduling.Secondly,we propose a new scheduling scheme based on the graded key security requirements(GKSR)and a new micro-log key storage algorithm for effective storage and management of key resources.Finally,we propose a key resource consumption(KRC)routing optimization algorithm to properly allocate time slots,routes,and key resources.Simulation results show that the proposed scheme significantly improves the key distribution success rate and key resource utilization rate,among others.
基金supported by National Key Research and Development Program of China(2018YFC1504502).
文摘Mobile edge computing(MEC)-enabled satellite-terrestrial networks(STNs)can provide Internet of Things(IoT)devices with global computing services.Sometimes,the network state information is uncertain or unknown.To deal with this situation,we investigate online learning-based offloading decision and resource allocation in MEC-enabled STNs in this paper.The problem of minimizing the average sum task completion delay of all IoT devices over all time periods is formulated.We decompose this optimization problem into a task offloading decision problem and a computing resource allocation problem.A joint optimization scheme of offloading decision and resource allocation is then proposed,which consists of a task offloading decision algorithm based on the devices cooperation aided upper confidence bound(UCB)algorithm and a computing resource allocation algorithm based on the Lagrange multiplier method.Simulation results validate that the proposed scheme performs better than other baseline schemes.
