To address the problem of high lifespan loss and poor state of charge(SOC)balance of electric vehicles(EVs)participating in grid peak shaving,an improved golden eagle optimizer(IGEO)algorithm for EV grouping control s...To address the problem of high lifespan loss and poor state of charge(SOC)balance of electric vehicles(EVs)participating in grid peak shaving,an improved golden eagle optimizer(IGEO)algorithm for EV grouping control strategy is proposed for peak shaving sce-narios.First,considering the difference between peak and valley loads and the operating costs of EVs,a peak shaving model for EVs is constructed.Second,the design of IGEO has improved the global exploration and local development capabilities of the golden eagle optimizer(GEO)algorithm.Subsequently,IGEO is used to solve the peak shaving model and obtain the overall EV grid connected charging and discharging instructions.Next,using the k-means algorithm,EVs are dynamically divided into priority charging groups,backup groups,and priority discharging groups based on SOC differences.Finally,a dual layer power distribution scheme for EVs is designed.The upper layer determines the charging and discharging sequences and instructions for the three groups of EVs,whereas the lower layer allocates the charging and discharging instructions for each group to each EV.The proposed strategy was simulated and verified,and the results showed that the designed IGEO had faster optimization speed and higher optimization accuracy.The pro-posed EV grouping control strategy effectively reduces the peak-valley difference in the power grid,reduces the operational life loss of EVs,and maintains a better SOC balance for EVs.展开更多
This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the...This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the MCNPX code for analysing neutron behavior and the PARET/ANL code for understanding power variations, to get a clearer picture of the reactor’s performance. The analysis covers the initial six years of GHARR-1’s operation and includes projections for its whole 60-year lifespan. We closely observed the patterns of both the highest and average PPFs at 21 axial nodes, with measurements taken every ten years. The findings of this study reveal important patterns in power distribution within the core, which are essential for improving the safety regulations and fuel management techniques of the reactor. We provide a meticulous approach, extensive data, and an analysis of the findings, highlighting the significance of continuous monitoring and analysis for proactive management of nuclear reactors. The findings of this study not only enhance our comprehension of nuclear reactor safety but also carry significant ramifications for sustainable energy progress in Ghana and the wider global context. Nuclear engineering is essential in tackling global concerns, such as the demand for clean and dependable energy sources. Research on optimising nuclear reactors, particularly in terms of safety and efficiency, is crucial for the ongoing advancement and acceptance of nuclear energy.展开更多
Many hydropower plants are operated as peak generators or frequency controllers, because they can change their output quickly to follow the fluctuating power demand. When meeting peak load requirements, a power statio...Many hydropower plants are operated as peak generators or frequency controllers, because they can change their output quickly to follow the fluctuating power demand. When meeting peak load requirements, a power station is turned on at a particular time during the day, generates power at a constant load for a certain number of hours, and is then turned off or set to a different load for another time period, resulting in a high variability inflow discharges. Where reservoir hydro schemes are operated primarily to provide peak load services, there are particular environmental risks that should be considered in any environmental impact assessment. At a minimum these should focus on water quality, fluvial geomorphology, riparian vegetation, macro-invertebrate and fish communities underpinned by a sound hydrological analysis. Frequent temperature changes may occur downstream of a peaking power station; increased seepage-induced erosion of riverbanks due to frequent water level drawdowns; and impacts to macro-invertebrate and fish communities due to rapid and frequent in channel habitat conditions. With a sound understanding of the potential environmental issues, there are strategies that can be employed at the siting and design stage to minimize or mitigate these risks, including but not limited to minimum environmental flows, ramping rules, utilization of a re-regulation storage and localized treatment works.展开更多
The impact of the E×B flow shear stabilization on particle transport and density peaking at JET is analyzed in the framework of integrated modelling with the CRONOS code.For that purpose,plasmas from a power scan...The impact of the E×B flow shear stabilization on particle transport and density peaking at JET is analyzed in the framework of integrated modelling with the CRONOS code.For that purpose,plasmas from a power scan which show a significant increasing of density peaking with the injected neutral beam injection power have been used as a modeling basis.By means of simulations with the quasilinear model GLF23 for the heat and particle transport,a strong link between the particle confinement and E×B flow shear stabilization is found.This is particularly important close to the pedestal region where the particle pinch direction becomes strongly inward for high E×B flow shear values.Such impact introduces some non-negligible deviation from the well-known collisonality dependence of the density peaking,whose general trend has been also obtained in the framework of this modelling by performing pedestal density scans.展开更多
There is a large amount of information in the network data that we canexploit. It is difficult for classical community detection algorithms to handle network data with sparse topology. Representation learning of netwo...There is a large amount of information in the network data that we canexploit. It is difficult for classical community detection algorithms to handle network data with sparse topology. Representation learning of network data is usually paired with clustering algorithms to solve the community detection problem.Meanwhile, there is always an unpredictable distribution of class clusters outputby graph representation learning. Therefore, we propose an improved densitypeak clustering algorithm (ILDPC) for the community detection problem, whichimproves the local density mechanism in the original algorithm and can betteraccommodate class clusters of different shapes. And we study the communitydetection in network data. The algorithm is paired with the benchmark modelGraph sample and aggregate (GraphSAGE) to show the adaptability of ILDPCfor community detection. The plotted decision diagram shows that the ILDPCalgorithm is more discriminative in selecting density peak points compared tothe original algorithm. Finally, the performance of K-means and other clusteringalgorithms on this benchmark model is compared, and the algorithm is proved tobe more suitable for community detection in sparse networks with the benchmarkmodel on the evaluation criterion F1-score. The sensitivity of the parameters ofthe ILDPC algorithm to the low-dimensional vector set output by the benchmarkmodel GraphSAGE is also analyzed.展开更多
The situation of China’s power industry to achieve carbon peaking and risks and challenges for China’s power industry to cope with carbon peaking were analyzed, and then macro countermeasures for the power industry ...The situation of China’s power industry to achieve carbon peaking and risks and challenges for China’s power industry to cope with carbon peaking were analyzed, and then macro countermeasures for the power industry to cope with carbon peaking were proposed.展开更多
In order to accurately predict the incident critical heat flux（ICHF,the heat flux at the heated surface when CHF occurs） of a water-cooled W/Cu monoblock for a divertor,the exact knowledge of its peaking factors（f_...In order to accurately predict the incident critical heat flux（ICHF,the heat flux at the heated surface when CHF occurs） of a water-cooled W/Cu monoblock for a divertor,the exact knowledge of its peaking factors（f_p） under one-sided heating conditions with different design parameters is a key issue.In this paper,the heat conduction in the solid domain of a water-cooled W/Cu monoblock is calculated numerically by assuming the local heat transfer coefficients（HTC）of the cooling wall to be functions of the local wall temperature,so as to obtain f_p.The reliability of the calculation method is validated by an experimental example result,with the maximum error of 2.1% only.The effects of geometric and flow parameters on the f_p of a water-cooled W/Cu monoblock are investigated.Within the scope of this study,it is shown that the f_p increases with increasing dimensionless W/Cu monoblock width and armour thickness（the shortest distance between the heated surface and Cu layer）,and the maximum increases are 43.8% and 22.4% respectively.The dimensionless W/Cu monoblock height and Cu thickness have little effect on f_p.The increase of Reynolds number and Jakob number causes the increase of f_p,and the maximum increases are 6.8% and 9.6% respectively.Based on the calculated results,an empirical correlation on peaking factor is obtained via regression.These results provide a valuable reference for the thermal-hydraulic design of water-cooled divertors.展开更多
With the goal of achieving carbon peak and carbon neutrality,this paper studies the carbon effect of agricultural land remediation.In this paper,the carbon effect mechanism and calculation method of land consolidation...With the goal of achieving carbon peak and carbon neutrality,this paper studies the carbon effect of agricultural land remediation.In this paper,the carbon effect mechanism and calculation method of land consolidation,the proposed national carbon peaking and carbon neutrality goals,and the requirements put forward by agricultural land consolidation followed were analyzed.Then,the application research on the carbon effect accounting of agricultural land consolidation was conducted.Besides,the application process of carbon effect accounting of land consolidation with the goals of carbon peaking and carbon neutrality.Therefore,we hope this study will play an effective role to advance the carbon effect research in the regulation of agricultural land.展开更多
The vision of reaching a carbon peak and achieving carbon neutrality is guiding the low-carbon transition of China’s socioeconomic system.Currently,a research gap remains in the existing literature in terms of studie...The vision of reaching a carbon peak and achieving carbon neutrality is guiding the low-carbon transition of China’s socioeconomic system.Currently,a research gap remains in the existing literature in terms of studies that systematically identify opportunities to achieve carbon neutrality.To address this gap,this study comprehensively collates and investigates 1105 published research studies regarding carbon peaking and carbon neutrality.In doing so,the principles of development in this area are quantitively analyzed from a space–time perspective.At the same time,this study traces shifts and alterations in research hotspots.This systematic review summarizes the priorities and standpoints of key industries on carbon peaking and carbon neutrality.Furthermore,with an emphasis on five key management science topics,the scientific concerns and strategic demands for these two carbon emission-reduction goals are clarified.The paper ends with theoretical insights on and practical countermeasures for actions,priority tasks,and policy measures that will enable China to achieve a carbon-neutral future.This study provides a complete picture of the research status on carbon peaking and carbon neutrality,as well as the research directions worth investigating in this field,which are crucial to the formulation of carbon peak and carbon neutrality policies.展开更多
China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching targe...China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching target and a key point of action for China＇s resource conservation, environmental protection, shift in economic development patterns, and CO2 emission reduction to avoid climate change. The development stage where China maps out the CO2 emission peak target is earlier than that of the developed countries. It is a necessity that the non-fossil energy supplies be able to meet all the increased energy demand for achieving CO2 emission peaking. Given that China＇s potential GDP annual increasing rate will be more than 4%, and China＇s total energy demand will continue to increase by approximately 1.0%--1.5% annually around 2030, new and renewable energies will need to increase by 6%-8% annually to meet the desired CO2 emission peak. The share of new and renewable energies in China＇s total primary energy supply will be approximately 20% by 2030. At that time, the energy consumption elasticity will decrease to around 0.3, and the annual decrease in the rate of CO2 intensity will also be higher than 4% to ensure the sustained growth of GDE To achieve the CO2 emission peaking target and substantially promote the low-carbon deve!opment transformation, China needs to actively promote an energy production and consumption revolution, the innovation of advanced energy technologies, the reform of the energy regulatory system and pricing mechanism, and especially the construction of a national carbon emission cap and trade system.展开更多
To achieve the goals of national sustainable development, the peaking control of CO2 emissions is pivotal, as well as other pollutants. In this paper, we build a Chinese inter-regional CGE model and simulate 13 polici...To achieve the goals of national sustainable development, the peaking control of CO2 emissions is pivotal, as well as other pollutants. In this paper, we build a Chinese inter-regional CGE model and simulate 13 policies and their combinations. By analyzing the energy consumptions, coal consumptions, relating emissions and their impacts on GDP, we found that with the structure adjustment policy, the proportion of coal in primary fossil fuels in 2030 will decrease from 53% to 48% and CO2 emissions will decrease by 11.3%-22.8% compared to the baseline scenario. With the energy intensity reduction policy, CO2 emissions will decrease by 33.3% in 2030 and 47.8% in 2050 than baseline scenario. Other pollutants will also be controlled as synergetic effects. In this study we also find that although the earlier the peaking time the better for emission amounts control, the economic costs can not be ignored. The GDP will decrease by 2.96%-8.23% under different scenarios. Therefore, integrated policy solutions are needed for realizing the peaks package and more targeted measures are required to achieve the peaks of other pollutants earlier.展开更多
The paper summarizes results of the China Energy Modeling Forum's(CEMF)first study.Carbon emissions peaking scenarios,consistent with China's Paris commitment,have been simulated with seven national and indust...The paper summarizes results of the China Energy Modeling Forum's(CEMF)first study.Carbon emissions peaking scenarios,consistent with China's Paris commitment,have been simulated with seven national and industry-level energy models and compared.The CO2 emission trends in the considered scenarios peak from 2015 to 2030 at the level of 9e11 Gt.Sector-level analysis suggests that total emissions pathways before 2030 will be determined mainly by dynamics of emissions in the electric power industry and transportation sector.Both sectors will experience significant increase in demand,but have low-carbon alternative options for development.Based on a side-by-side comparison of modeling input and results,conclusions have been drawn regarding the sources of emissions projections differences,which include data,views on economic perspectives,or models'structure and theoretical framework.Some suggestions have been made regarding energy models'development priorities for further research.展开更多
In 2022,Chinese policymakers emphasized the importance of leveraging the country's domestic energy resource endowments and implementing a phased and well-planned carbon peaking strategy by following the principle ...In 2022,Chinese policymakers emphasized the importance of leveraging the country's domestic energy resource endowments and implementing a phased and well-planned carbon peaking strategy by following the principle of"establishing the new before phasing out the old".To explore the carbon reduction potential and path optimization in resource-based regions undergoing energy structure adjustments,this study employed the Long-range Energy Alternatives Planning System(LEAP)to simulate and analyze both a baseline scenario and a comprehensive policy intervention scenario from 2021 to 2050.This study focused on the typical resource-based region of Inner Mongolia Autonomous Region and developed a customized"LEAP-Inner Mongolia"model.The findings reveal that:(1)Under the comprehensive scenario,energy demand is notably reduced by 2050,with total carbon emissions cut by 70.96%compared to the baseline scenario;(2)The Environmental Kuznets Curve(EKC)analysis suggests a persistent rise in emissions under the baseline scenario,while a carbon peak is achieved as early as 2029 under the integrated scenario;and(3)There are limitations of isolated policy instruments so a synergistic approach that integrates power generation structure optimization with improvements in energy efficiency is necessary.Accordingly,we propose a multi-pronged policy portfolio that includes the synchronized development of clean energy and efficient end-use systems,industrial low-carbon transformation,accelerated adoption of new energy vehicles,and improved inter-regional coordination.These recommendations can offer systemic insights for guiding low-carbon transitions in resource-based areas.展开更多
As the total amount and share of new energy installed capacity continue to rise,the demand for flexible regulation capability of the power system is becoming more and more prominent.The current conventional molten sal...As the total amount and share of new energy installed capacity continue to rise,the demand for flexible regulation capability of the power system is becoming more and more prominent.The current conventional molten salt energy storage system has insufficient peaking capacity.A solar-molten salt energy storage system based on multiple heat sources is constructed in this study.The heat generated from the solar field and the steams are used for the peaking process to further enhance the peaking capacity and flexibility.The installation multi-stage steam extraction and the introduction of an external heat source significantly improve the system performance.The simulation models based on EBSILON software are developed and the effects of key parameters on performance are discussed.The feasibility of the proposed system is further evaluated in terms of exergy and economy.The results demonstrate that the proposed SF-TES-CFPP(solar field,thermal energy storage system,coal-fired power plant)system exhibits the enhancement of peaking capability and flexible operation.In comparison with the conventional TES-CFPP,the integration of solar energy into the peaking process has enabled the SF-TES-CFPP system to enhance its peaking capacity by 20.60 MW while concurrently reducing the coal consumption rate by 10.26 g/kWh.The round-trip efficiency of the whole process of the system can be up to 85.43%through the reasonable heat distribution.In addition,the exergy loss of the principal components can be diminished and the exergy efficiency of the system can be augmented by selecting an appropriate main steam extraction mass and split ratio.The economic analysis demonstrates the dynamic payback period is 9.90 years with the net present value(NPV)across the entire life cycle reaching 1.06902×10^(9)USD.展开更多
Consolidating carbon sink capacity and reducing carbon pressure are important channels to achieve the carbon peaking and carbon neutrality goals actively yet prudently.In order to study the current situation of carbon...Consolidating carbon sink capacity and reducing carbon pressure are important channels to achieve the carbon peaking and carbon neutrality goals actively yet prudently.In order to study the current situation of carbon pressure in the Northwestern Sichuan,we took the carbon pressure of the Aba Tibetan-Qiang autonomous prefecture(Aba prefecture)as an example and used the Intergovernmental Panel on Climate Change(IPCC)approach to measure the carbon emissions,carbon uptake,and the carbon balance index(CBI)of each county-level city in Aba prefecture from 2012 to 2020.The study found that:(a)There was a continuous trend of declining carbon emissions,increased carbon uptake,and decreased CBI in Aba prefecture during the sample period,but there is a large variability among county-level cities;(b)Aba prefecture differs in the spatiotemporal distribution of carbon emissions,carbon uptake,and CBI.Based on the research results,we propose several optimized paths for alleviating the current carbon pressure situation in the Northwestern Sichuan.展开更多
This work presents a PAM4 receiver analog frontend(AFE)operating up to 64 Gb/s.The electronic integrated circuit(EIC)is fabricated in 40-nm CMOS technology.This AFE is composed of a single-stage Continuous-Time Linear...This work presents a PAM4 receiver analog frontend(AFE)operating up to 64 Gb/s.The electronic integrated circuit(EIC)is fabricated in 40-nm CMOS technology.This AFE is composed of a single-stage Continuous-Time Linear Equalizer(CTLE),a Variable Gain Amplifier(VGA),an input impedance matching network,a buffer stage,and an output buffer.The single-stage triple-peaking CTLE proposed employs current reuse technique and a multi-feedback structure,enabling the adjustment of peaking in the low,mid,and high-frequency bands.Thus,only one-stage CTLE is sufficient to achieve an over-20-dB boost at Nyquist frequency to save power.The VGA adopts an enhanced structure based on the Gilbert cell,where the gain is manipulated by controlling the gate voltage of MOS transistors.The CTLE undergoes variations in its DC gain during the adjustment process to equalize channel losses.The role of the VGA is to stable the DC gain changes induced by the adjustment of the CTLE.The output buffer adopts two stages,aiming to ensure that the gain does not attenuate excessively while maintaining output impedance matching.The AFE consumes 21.1 mW with a supply voltage of 1.5/1 V.It can provide a maximum boost of 22.5 dB,and the data rate reaches up to 64 Gb/s.Additionally,it features peaking adjustment capabilities in the low,mid,and high-frequency bands.Finally,the measurement demonstrates its ability to effectively equalize a channel with a 12-dB loss at the Nyquist frequency of 16 GHz.展开更多
In the context of China’s resolute advancement of dual carbon goals(carbon peaking and carbon neutrality),urban agglomerations emerge as pivotal areas for carbon emission mitigation due to their dense economic activi...In the context of China’s resolute advancement of dual carbon goals(carbon peaking and carbon neutrality),urban agglomerations emerge as pivotal areas for carbon emission mitigation due to their dense economic activities and rapid urbanization.Previous studies overlook regional disparities in carbon emission prediction,disregarding the variations and policy directives across different provinces or cities.Therefore,this study addresses the research gap by investigating synergistic strategies to foster regional carbon peaking within the Beijing-Tianjin-Hebei region.Employing a novel approach tailored to regional segmentation policies,we provide more accurate predictions reflect-ing real-world conditions and distinct policy landscapes.Meanwhile,we integrate carbon emission efficiency into our analysis,emphasizing the dual goals of emission reduction and quality economic growth.Our empirical investigation in the Beijing-Tianjin-Hebei region,utilizing the Super-SBM and extended STIRPAT models,reveals upward trends in carbon emission efficiency,with varying trajectories across cities.Scenario simulations informed by the"14th Five-Year Plan"demonstrate that under the green development scenario,carbon peaking accelerates,alongside enhanced efficiency,supporting long-term emission reduction.Moreover,we design seven regional synergy carbon peak strate-gies for scenario simulations to facilitate the rational layout of dual carbon policies for collaborative development.We find that synergistic strategies have proven more effective in reducing regional carbon emission and increasing efficiency than strategies focusing solely on economic development or energy conservation.This innovative finding emphasizes the necessity of comprehensive green development in the Beijing-Tianjin-Hebei region and provides strong evidence for policymakers.Our research contributes to targeted strategies for improving carbon emission effi-ciency and reducing emissions,emphasizing the importance of synergistic approaches for regional carbon reduction.展开更多
Carbon dioxide is the main factor causing the greenhouse effect,and reducing carbon dioxide emissions is an important task in ecological civilization governance.The audit of outgoing officials'natural resource ass...Carbon dioxide is the main factor causing the greenhouse effect,and reducing carbon dioxide emissions is an important task in ecological civilization governance.The audit of outgoing officials'natural resource asset management is an audit of the natural resources within the jurisdiction of each province to ensure that senior officials implement policies to protect natural resources.Therefore,this paper empirically verifies the impact of audit outgoing officials'natural resource asset management on carbon emission reduction based on panel data of 297 prefecture-level cities in China from 2012 to 2021.The study finds that auditing outgoing officials'natural resource asset management can effectively reduce carbon dioxide emissions and achieve energy conservation and emission reduction.Further research finds that auditing outgoing officials'natural resource asset management can promote technological innovation and industrial structure optimization,providing a reference for the country to achieve carbon peaking and carbon neutrality goals and promote the green transformation and upgrading of social development.展开更多
With the gradually widely usage of the air conditioning(AC) loads in developing countries, the urban power grid load has swiftly increased over the past decade.Especially in China, the AC load has accounted for over30...With the gradually widely usage of the air conditioning(AC) loads in developing countries, the urban power grid load has swiftly increased over the past decade.Especially in China, the AC load has accounted for over30% of the maximum load in many cities during summer.This paper proposes a scheme of constructing a virtual peaking unit(VPU) by public buildings’ cool storage central AC(CSCAC) systems and non-CSCAC(NCSCAC)systems for the day-ahead power network dispatching(DAPND). Considering the accumulation effect of different meteorological parameters, a short term load forecasting method of public building’s central AC(CAC) baseline load is firstly discussed. Then, a second-order equivalent thermal parameters model is established for the public building’s CAC load. Moreover, the novel load reduction control strategies for the public building’s CSCAC system and the public building’s NCSCAC system are respectively presented. Furthermore, based on the multiple-rank control strategy, the model of the DAPND with the participation of a VPU is set up. The VPU is composed of large-scale regulated public building’s CAC loads. To demonstrate the effectiveness of the proposed strategy, results of a sample study on a region in Nanjing which involves 22 public buildings’ CAC loads are described in this paper. Simulated results show that, by adopting the proposed DAPND scheme, the power network peak load in the region obviously decreases with a small enough deviation between the regulated load value and the dispatching instruction of the VPU. The total electricity-saving amount accounts for7.78% of total electricity consumption of the VPU before regulation.展开更多
基金supported by the National Natural Science Foundation of China(52077078)China Southern Power Grid Company Limited 036000KK52220004(GDKJXM20220147).
文摘To address the problem of high lifespan loss and poor state of charge(SOC)balance of electric vehicles(EVs)participating in grid peak shaving,an improved golden eagle optimizer(IGEO)algorithm for EV grouping control strategy is proposed for peak shaving sce-narios.First,considering the difference between peak and valley loads and the operating costs of EVs,a peak shaving model for EVs is constructed.Second,the design of IGEO has improved the global exploration and local development capabilities of the golden eagle optimizer(GEO)algorithm.Subsequently,IGEO is used to solve the peak shaving model and obtain the overall EV grid connected charging and discharging instructions.Next,using the k-means algorithm,EVs are dynamically divided into priority charging groups,backup groups,and priority discharging groups based on SOC differences.Finally,a dual layer power distribution scheme for EVs is designed.The upper layer determines the charging and discharging sequences and instructions for the three groups of EVs,whereas the lower layer allocates the charging and discharging instructions for each group to each EV.The proposed strategy was simulated and verified,and the results showed that the designed IGEO had faster optimization speed and higher optimization accuracy.The pro-posed EV grouping control strategy effectively reduces the peak-valley difference in the power grid,reduces the operational life loss of EVs,and maintains a better SOC balance for EVs.
文摘This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the MCNPX code for analysing neutron behavior and the PARET/ANL code for understanding power variations, to get a clearer picture of the reactor’s performance. The analysis covers the initial six years of GHARR-1’s operation and includes projections for its whole 60-year lifespan. We closely observed the patterns of both the highest and average PPFs at 21 axial nodes, with measurements taken every ten years. The findings of this study reveal important patterns in power distribution within the core, which are essential for improving the safety regulations and fuel management techniques of the reactor. We provide a meticulous approach, extensive data, and an analysis of the findings, highlighting the significance of continuous monitoring and analysis for proactive management of nuclear reactors. The findings of this study not only enhance our comprehension of nuclear reactor safety but also carry significant ramifications for sustainable energy progress in Ghana and the wider global context. Nuclear engineering is essential in tackling global concerns, such as the demand for clean and dependable energy sources. Research on optimising nuclear reactors, particularly in terms of safety and efficiency, is crucial for the ongoing advancement and acceptance of nuclear energy.
文摘Many hydropower plants are operated as peak generators or frequency controllers, because they can change their output quickly to follow the fluctuating power demand. When meeting peak load requirements, a power station is turned on at a particular time during the day, generates power at a constant load for a certain number of hours, and is then turned off or set to a different load for another time period, resulting in a high variability inflow discharges. Where reservoir hydro schemes are operated primarily to provide peak load services, there are particular environmental risks that should be considered in any environmental impact assessment. At a minimum these should focus on water quality, fluvial geomorphology, riparian vegetation, macro-invertebrate and fish communities underpinned by a sound hydrological analysis. Frequent temperature changes may occur downstream of a peaking power station; increased seepage-induced erosion of riverbanks due to frequent water level drawdowns; and impacts to macro-invertebrate and fish communities due to rapid and frequent in channel habitat conditions. With a sound understanding of the potential environmental issues, there are strategies that can be employed at the siting and design stage to minimize or mitigate these risks, including but not limited to minimum environmental flows, ramping rules, utilization of a re-regulation storage and localized treatment works.
基金supported by The Franco-Thai scholarship program and Development and Promotion of Science and Technology Talents Projectbeen carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No.633053。
文摘The impact of the E×B flow shear stabilization on particle transport and density peaking at JET is analyzed in the framework of integrated modelling with the CRONOS code.For that purpose,plasmas from a power scan which show a significant increasing of density peaking with the injected neutral beam injection power have been used as a modeling basis.By means of simulations with the quasilinear model GLF23 for the heat and particle transport,a strong link between the particle confinement and E×B flow shear stabilization is found.This is particularly important close to the pedestal region where the particle pinch direction becomes strongly inward for high E×B flow shear values.Such impact introduces some non-negligible deviation from the well-known collisonality dependence of the density peaking,whose general trend has been also obtained in the framework of this modelling by performing pedestal density scans.
基金The National Natural Science Foundation of China(No.61762031)The Science and Technology Major Project of Guangxi Province(NO.AA19046004)The Natural Science Foundation of Guangxi(No.2021JJA170130).
文摘There is a large amount of information in the network data that we canexploit. It is difficult for classical community detection algorithms to handle network data with sparse topology. Representation learning of network data is usually paired with clustering algorithms to solve the community detection problem.Meanwhile, there is always an unpredictable distribution of class clusters outputby graph representation learning. Therefore, we propose an improved densitypeak clustering algorithm (ILDPC) for the community detection problem, whichimproves the local density mechanism in the original algorithm and can betteraccommodate class clusters of different shapes. And we study the communitydetection in network data. The algorithm is paired with the benchmark modelGraph sample and aggregate (GraphSAGE) to show the adaptability of ILDPCfor community detection. The plotted decision diagram shows that the ILDPCalgorithm is more discriminative in selecting density peak points compared tothe original algorithm. Finally, the performance of K-means and other clusteringalgorithms on this benchmark model is compared, and the algorithm is proved tobe more suitable for community detection in sparse networks with the benchmarkmodel on the evaluation criterion F1-score. The sensitivity of the parameters ofthe ILDPC algorithm to the low-dimensional vector set output by the benchmarkmodel GraphSAGE is also analyzed.
基金Supported by the Science and Technology Achievement Transformation Project of Jiangsu Province,China (BA2020001)Special Project for Fixed-source Air Pollution Prevention and Control Research of the Ministry of Ecology and Environment in 2020 (2020A060)。
文摘The situation of China’s power industry to achieve carbon peaking and risks and challenges for China’s power industry to cope with carbon peaking were analyzed, and then macro countermeasures for the power industry to cope with carbon peaking were proposed.
基金supported by National Magnetic Confinement Fusion Science Program of China(No.2010GB104005)Funding of Jiangsu Innovation Program for Graduate Education,China(CXLX12_0170)the Fundamental Research Funds for the Central Universities of China
文摘In order to accurately predict the incident critical heat flux（ICHF,the heat flux at the heated surface when CHF occurs） of a water-cooled W/Cu monoblock for a divertor,the exact knowledge of its peaking factors（f_p） under one-sided heating conditions with different design parameters is a key issue.In this paper,the heat conduction in the solid domain of a water-cooled W/Cu monoblock is calculated numerically by assuming the local heat transfer coefficients（HTC）of the cooling wall to be functions of the local wall temperature,so as to obtain f_p.The reliability of the calculation method is validated by an experimental example result,with the maximum error of 2.1% only.The effects of geometric and flow parameters on the f_p of a water-cooled W/Cu monoblock are investigated.Within the scope of this study,it is shown that the f_p increases with increasing dimensionless W/Cu monoblock width and armour thickness（the shortest distance between the heated surface and Cu layer）,and the maximum increases are 43.8% and 22.4% respectively.The dimensionless W/Cu monoblock height and Cu thickness have little effect on f_p.The increase of Reynolds number and Jakob number causes the increase of f_p,and the maximum increases are 6.8% and 9.6% respectively.Based on the calculated results,an empirical correlation on peaking factor is obtained via regression.These results provide a valuable reference for the thermal-hydraulic design of water-cooled divertors.
文摘With the goal of achieving carbon peak and carbon neutrality,this paper studies the carbon effect of agricultural land remediation.In this paper,the carbon effect mechanism and calculation method of land consolidation,the proposed national carbon peaking and carbon neutrality goals,and the requirements put forward by agricultural land consolidation followed were analyzed.Then,the application research on the carbon effect accounting of agricultural land consolidation was conducted.Besides,the application process of carbon effect accounting of land consolidation with the goals of carbon peaking and carbon neutrality.Therefore,we hope this study will play an effective role to advance the carbon effect research in the regulation of agricultural land.
基金the National Natural Science Foundation of China(71521002,72104025,and 72004011)China’s National Key Research and Development(R&D)Program(2016YFA0602603)China Post-doctoral Science Foundation(2021M690014)。
文摘The vision of reaching a carbon peak and achieving carbon neutrality is guiding the low-carbon transition of China’s socioeconomic system.Currently,a research gap remains in the existing literature in terms of studies that systematically identify opportunities to achieve carbon neutrality.To address this gap,this study comprehensively collates and investigates 1105 published research studies regarding carbon peaking and carbon neutrality.In doing so,the principles of development in this area are quantitively analyzed from a space–time perspective.At the same time,this study traces shifts and alterations in research hotspots.This systematic review summarizes the priorities and standpoints of key industries on carbon peaking and carbon neutrality.Furthermore,with an emphasis on five key management science topics,the scientific concerns and strategic demands for these two carbon emission-reduction goals are clarified.The paper ends with theoretical insights on and practical countermeasures for actions,priority tasks,and policy measures that will enable China to achieve a carbon-neutral future.This study provides a complete picture of the research status on carbon peaking and carbon neutrality,as well as the research directions worth investigating in this field,which are crucial to the formulation of carbon peak and carbon neutrality policies.
基金supported by Major Program of Humanities and Social Science Base,Ministry of Education(No.10JJD630011)
文摘China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching target and a key point of action for China＇s resource conservation, environmental protection, shift in economic development patterns, and CO2 emission reduction to avoid climate change. The development stage where China maps out the CO2 emission peak target is earlier than that of the developed countries. It is a necessity that the non-fossil energy supplies be able to meet all the increased energy demand for achieving CO2 emission peaking. Given that China＇s potential GDP annual increasing rate will be more than 4%, and China＇s total energy demand will continue to increase by approximately 1.0%--1.5% annually around 2030, new and renewable energies will need to increase by 6%-8% annually to meet the desired CO2 emission peak. The share of new and renewable energies in China＇s total primary energy supply will be approximately 20% by 2030. At that time, the energy consumption elasticity will decrease to around 0.3, and the annual decrease in the rate of CO2 intensity will also be higher than 4% to ensure the sustained growth of GDE To achieve the CO2 emission peaking target and substantially promote the low-carbon deve!opment transformation, China needs to actively promote an energy production and consumption revolution, the innovation of advanced energy technologies, the reform of the energy regulatory system and pricing mechanism, and especially the construction of a national carbon emission cap and trade system.
基金funded by the National Natural Fund of China(71173206)the Strategic Priority Research ProgramdClimate Change:Carbon Budget and Related Issues of the Chinese Academy of Sciences(XDA05150300)
文摘To achieve the goals of national sustainable development, the peaking control of CO2 emissions is pivotal, as well as other pollutants. In this paper, we build a Chinese inter-regional CGE model and simulate 13 policies and their combinations. By analyzing the energy consumptions, coal consumptions, relating emissions and their impacts on GDP, we found that with the structure adjustment policy, the proportion of coal in primary fossil fuels in 2030 will decrease from 53% to 48% and CO2 emissions will decrease by 11.3%-22.8% compared to the baseline scenario. With the energy intensity reduction policy, CO2 emissions will decrease by 33.3% in 2030 and 47.8% in 2050 than baseline scenario. Other pollutants will also be controlled as synergetic effects. In this study we also find that although the earlier the peaking time the better for emission amounts control, the economic costs can not be ignored. The GDP will decrease by 2.96%-8.23% under different scenarios. Therefore, integrated policy solutions are needed for realizing the peaks package and more targeted measures are required to achieve the peaks of other pollutants earlier.
文摘The paper summarizes results of the China Energy Modeling Forum's(CEMF)first study.Carbon emissions peaking scenarios,consistent with China's Paris commitment,have been simulated with seven national and industry-level energy models and compared.The CO2 emission trends in the considered scenarios peak from 2015 to 2030 at the level of 9e11 Gt.Sector-level analysis suggests that total emissions pathways before 2030 will be determined mainly by dynamics of emissions in the electric power industry and transportation sector.Both sectors will experience significant increase in demand,but have low-carbon alternative options for development.Based on a side-by-side comparison of modeling input and results,conclusions have been drawn regarding the sources of emissions projections differences,which include data,views on economic perspectives,or models'structure and theoretical framework.Some suggestions have been made regarding energy models'development priorities for further research.
基金The National Social Science Fund of China(22XGL002)。
文摘In 2022,Chinese policymakers emphasized the importance of leveraging the country's domestic energy resource endowments and implementing a phased and well-planned carbon peaking strategy by following the principle of"establishing the new before phasing out the old".To explore the carbon reduction potential and path optimization in resource-based regions undergoing energy structure adjustments,this study employed the Long-range Energy Alternatives Planning System(LEAP)to simulate and analyze both a baseline scenario and a comprehensive policy intervention scenario from 2021 to 2050.This study focused on the typical resource-based region of Inner Mongolia Autonomous Region and developed a customized"LEAP-Inner Mongolia"model.The findings reveal that:(1)Under the comprehensive scenario,energy demand is notably reduced by 2050,with total carbon emissions cut by 70.96%compared to the baseline scenario;(2)The Environmental Kuznets Curve(EKC)analysis suggests a persistent rise in emissions under the baseline scenario,while a carbon peak is achieved as early as 2029 under the integrated scenario;and(3)There are limitations of isolated policy instruments so a synergistic approach that integrates power generation structure optimization with improvements in energy efficiency is necessary.Accordingly,we propose a multi-pronged policy portfolio that includes the synchronized development of clean energy and efficient end-use systems,industrial low-carbon transformation,accelerated adoption of new energy vehicles,and improved inter-regional coordination.These recommendations can offer systemic insights for guiding low-carbon transitions in resource-based areas.
基金supported by the National Key R&D Program(No.2022YFB4202404)。
文摘As the total amount and share of new energy installed capacity continue to rise,the demand for flexible regulation capability of the power system is becoming more and more prominent.The current conventional molten salt energy storage system has insufficient peaking capacity.A solar-molten salt energy storage system based on multiple heat sources is constructed in this study.The heat generated from the solar field and the steams are used for the peaking process to further enhance the peaking capacity and flexibility.The installation multi-stage steam extraction and the introduction of an external heat source significantly improve the system performance.The simulation models based on EBSILON software are developed and the effects of key parameters on performance are discussed.The feasibility of the proposed system is further evaluated in terms of exergy and economy.The results demonstrate that the proposed SF-TES-CFPP(solar field,thermal energy storage system,coal-fired power plant)system exhibits the enhancement of peaking capability and flexible operation.In comparison with the conventional TES-CFPP,the integration of solar energy into the peaking process has enabled the SF-TES-CFPP system to enhance its peaking capacity by 20.60 MW while concurrently reducing the coal consumption rate by 10.26 g/kWh.The round-trip efficiency of the whole process of the system can be up to 85.43%through the reasonable heat distribution.In addition,the exergy loss of the principal components can be diminished and the exergy efficiency of the system can be augmented by selecting an appropriate main steam extraction mass and split ratio.The economic analysis demonstrates the dynamic payback period is 9.90 years with the net present value(NPV)across the entire life cycle reaching 1.06902×10^(9)USD.
基金This paper is part of“A Study on the Spatiotemporal Evolution,Dilemma and Optimized Paths of Carbon Balance in Aba Prefecture Under the Carbon Peaking and Carbon Neutrality Goals”(ABKT2022065)a program funded by the Prefecture Social Science Fund Project of Aba Prefecture。
文摘Consolidating carbon sink capacity and reducing carbon pressure are important channels to achieve the carbon peaking and carbon neutrality goals actively yet prudently.In order to study the current situation of carbon pressure in the Northwestern Sichuan,we took the carbon pressure of the Aba Tibetan-Qiang autonomous prefecture(Aba prefecture)as an example and used the Intergovernmental Panel on Climate Change(IPCC)approach to measure the carbon emissions,carbon uptake,and the carbon balance index(CBI)of each county-level city in Aba prefecture from 2012 to 2020.The study found that:(a)There was a continuous trend of declining carbon emissions,increased carbon uptake,and decreased CBI in Aba prefecture during the sample period,but there is a large variability among county-level cities;(b)Aba prefecture differs in the spatiotemporal distribution of carbon emissions,carbon uptake,and CBI.Based on the research results,we propose several optimized paths for alleviating the current carbon pressure situation in the Northwestern Sichuan.
基金supported by the National Natural Science Foundation of China under Grant 62222409 and Grant 62174153.
文摘This work presents a PAM4 receiver analog frontend(AFE)operating up to 64 Gb/s.The electronic integrated circuit(EIC)is fabricated in 40-nm CMOS technology.This AFE is composed of a single-stage Continuous-Time Linear Equalizer(CTLE),a Variable Gain Amplifier(VGA),an input impedance matching network,a buffer stage,and an output buffer.The single-stage triple-peaking CTLE proposed employs current reuse technique and a multi-feedback structure,enabling the adjustment of peaking in the low,mid,and high-frequency bands.Thus,only one-stage CTLE is sufficient to achieve an over-20-dB boost at Nyquist frequency to save power.The VGA adopts an enhanced structure based on the Gilbert cell,where the gain is manipulated by controlling the gate voltage of MOS transistors.The CTLE undergoes variations in its DC gain during the adjustment process to equalize channel losses.The role of the VGA is to stable the DC gain changes induced by the adjustment of the CTLE.The output buffer adopts two stages,aiming to ensure that the gain does not attenuate excessively while maintaining output impedance matching.The AFE consumes 21.1 mW with a supply voltage of 1.5/1 V.It can provide a maximum boost of 22.5 dB,and the data rate reaches up to 64 Gb/s.Additionally,it features peaking adjustment capabilities in the low,mid,and high-frequency bands.Finally,the measurement demonstrates its ability to effectively equalize a channel with a 12-dB loss at the Nyquist frequency of 16 GHz.
基金supported by the grant from the National Natural Science Foundation of China(52270174).
文摘In the context of China’s resolute advancement of dual carbon goals(carbon peaking and carbon neutrality),urban agglomerations emerge as pivotal areas for carbon emission mitigation due to their dense economic activities and rapid urbanization.Previous studies overlook regional disparities in carbon emission prediction,disregarding the variations and policy directives across different provinces or cities.Therefore,this study addresses the research gap by investigating synergistic strategies to foster regional carbon peaking within the Beijing-Tianjin-Hebei region.Employing a novel approach tailored to regional segmentation policies,we provide more accurate predictions reflect-ing real-world conditions and distinct policy landscapes.Meanwhile,we integrate carbon emission efficiency into our analysis,emphasizing the dual goals of emission reduction and quality economic growth.Our empirical investigation in the Beijing-Tianjin-Hebei region,utilizing the Super-SBM and extended STIRPAT models,reveals upward trends in carbon emission efficiency,with varying trajectories across cities.Scenario simulations informed by the"14th Five-Year Plan"demonstrate that under the green development scenario,carbon peaking accelerates,alongside enhanced efficiency,supporting long-term emission reduction.Moreover,we design seven regional synergy carbon peak strate-gies for scenario simulations to facilitate the rational layout of dual carbon policies for collaborative development.We find that synergistic strategies have proven more effective in reducing regional carbon emission and increasing efficiency than strategies focusing solely on economic development or energy conservation.This innovative finding emphasizes the necessity of comprehensive green development in the Beijing-Tianjin-Hebei region and provides strong evidence for policymakers.Our research contributes to targeted strategies for improving carbon emission effi-ciency and reducing emissions,emphasizing the importance of synergistic approaches for regional carbon reduction.
基金supported by the National Pre-Research Project of Hebei GEO University(Grant No.KY2024YB19)the 2023-2024 Hebei Higher Education Teaching Reform Research and Practice Project(Grant No.2023GJJG302)+4 种基金Regional System Research Center of Hebei GEO University(Grant No.QYZDYJZX202525)Smart Financial Technology Innovation Center of Hebei Province(Grant No.HBZX202401004)Hebei Geo University graduate course construction project in 2025(Grant No.YKSZ2025006)Major Research Project on Humanities and Social Sciences in Colleges and Universities of Hebei Province(Grant No.ZD202418)Teaching Case of Hebei GEO University MBA Case Center in 2025(Grant No.AL202511).
文摘Carbon dioxide is the main factor causing the greenhouse effect,and reducing carbon dioxide emissions is an important task in ecological civilization governance.The audit of outgoing officials'natural resource asset management is an audit of the natural resources within the jurisdiction of each province to ensure that senior officials implement policies to protect natural resources.Therefore,this paper empirically verifies the impact of audit outgoing officials'natural resource asset management on carbon emission reduction based on panel data of 297 prefecture-level cities in China from 2012 to 2021.The study finds that auditing outgoing officials'natural resource asset management can effectively reduce carbon dioxide emissions and achieve energy conservation and emission reduction.Further research finds that auditing outgoing officials'natural resource asset management can promote technological innovation and industrial structure optimization,providing a reference for the country to achieve carbon peaking and carbon neutrality goals and promote the green transformation and upgrading of social development.
基金supported by National Key Technology Support Program (No. 2013BAA01B00)National Natural Science Foundation of China (No. 51361130152, No. 51577028)
文摘With the gradually widely usage of the air conditioning(AC) loads in developing countries, the urban power grid load has swiftly increased over the past decade.Especially in China, the AC load has accounted for over30% of the maximum load in many cities during summer.This paper proposes a scheme of constructing a virtual peaking unit(VPU) by public buildings’ cool storage central AC(CSCAC) systems and non-CSCAC(NCSCAC)systems for the day-ahead power network dispatching(DAPND). Considering the accumulation effect of different meteorological parameters, a short term load forecasting method of public building’s central AC(CAC) baseline load is firstly discussed. Then, a second-order equivalent thermal parameters model is established for the public building’s CAC load. Moreover, the novel load reduction control strategies for the public building’s CSCAC system and the public building’s NCSCAC system are respectively presented. Furthermore, based on the multiple-rank control strategy, the model of the DAPND with the participation of a VPU is set up. The VPU is composed of large-scale regulated public building’s CAC loads. To demonstrate the effectiveness of the proposed strategy, results of a sample study on a region in Nanjing which involves 22 public buildings’ CAC loads are described in this paper. Simulated results show that, by adopting the proposed DAPND scheme, the power network peak load in the region obviously decreases with a small enough deviation between the regulated load value and the dispatching instruction of the VPU. The total electricity-saving amount accounts for7.78% of total electricity consumption of the VPU before regulation.
