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research on ECMS Based on Segmented Path Braking energy Recovery in a Fuel Cell Vehicle

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energy Engineering 2024年第1期121卷 95-110页

作者： Wen Sun Meijing Li Guoxiang Li Ke Sun Shuzhan Bai School of energy and Power Engineering Shandong UniversityJinan250061China Automotive research Institute China National Heavy Duty Truck Group Co.Ltd.Jinan250061China

Proton exchange membrane fuel cells are widely regarded as having the potential to replace internal combustion engines in vehicles.Since fuel cells cannot recover energy and have a slow dynamic response,they need to be used with different power sources.Developing efficient energy management strategies to achieve excellent fuel economy is the goal of research.This paper proposes an adaptive equivalent fuel minimum consumption strategy(AECMS)to solve the problem of the poor economy of the whole vehicle caused by the wrong selection of equivalent factors(EF)in traditional ECMS.In this method,the kinematics interval is used to update the equivalent factor by considering the penalty term of energy recovery on SOC changes.Finally,the optimized equivalent factor is substituted into the optimization objective function to achieve efficient energy regulation.Simulation results under the New European Driving Cycle show that compared with the traditional ECMS based on fixed SOC benchmarks,the proposed method improves fuel economy by 1.7%while ensuring vehicle power and increases SOC by 30%.

关键词： Fuel cell PEMFC electric vehicle equivalent consumption minimization strategy

Proactive Resilience Enhancement of Power Systems with Link Transmission Model-based Dynamic Traffic Assignment Among Electric Vehicles

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CSEE Journal of Power and energy Systems 2024年第3期10卷 1320-1330页

作者： Haoyuan Yan Tianyang Zhao Zhanglei Guan energy Electricity research Center Jinan UniversityGuangzhou 510632China energy research Institute Nanyang Technological UniversitySingapore IEEE

The rapid development of electric vehicles(EVs)is strengthening the bi-directional interactions between electric power networks(EPNs)and transportation networks(TNs)while providing opportunities to enhance the resilience of power systems towards extreme events.To quantify the temporal and spatial flexibility of EVs for charging and discharging,a novel dynamic traffic assignment(DTA)problem is proposed.The DTA problem is based on a link transmission model(LTM)with extended charging links,depicting the interaction between EVs and power systems.It models the charging rates as continuous variables by an energy boundary model.To consider the evacuation requirements of TNs and the uncertainties of traffic conditions,the DTA problem is extended to a two-stage distributionally robust version.It is further incorporated into a two-stage distributionally robust unit commitment problem to balance the enhancement of EPNs and the performance of TNs.The problem is reformulated into a mixed-integer linear programming problem and solved by off-the-shelf commercial solvers.Case studies are performed on two test networks.The effectiveness is verified by the numerical results,e.g.,reducing the load shedding amount without increasing the unmet traffic demand.

关键词： Coupled transportation and power network link transmission model resilience enhancement

Overview of research and development of nearly zero energy buildings in China

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National Science Open 2024年第3期3卷 70-87页

作者： Zhen Yu Caifeng Gao Jiaxin Yang Jianlin Wu Huan Zhang Institute of Building Environment and energy China Academy of Building Research

In recent years,the promotion of nearly zero-energy buildings(NZEBs) in China has emerged as a crucial step for the building industry in shifting towards a green and low-carbon future.Starting from scratch,the development of NZEBs in China has included the application and fundamental research,the compilation of national and local standards,and the rapid emergence of projects encompassing 23.89 million square meters nationwide.These efforts have yielded preliminary results in national standards,technology systems,technical roadmaps,and large-scale project demonstrations.However,challenges,including further reducing incremental costs,developing industries for retrotitting existing buildings into NZEBs,and expanding the range of policy incentives,remain to be addressed.This article provides an overview of the last decade's progress in NZEBs in China,covering key technological research,policy development,engineering demonstrations,and the current industrial development status.Finally,the prospects of the NZEB industry are discussed.

关键词： nearly zero-energy buildings (NZEB) overview cost incentive policy demonstration

Recent progress on electro-sorption technology for lithium recovery from aqueous sources

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Nano research 2024年第4期17卷 2563-2573页

作者： Qichen Lu Peng Liu Tianyi Zhou Ruling Huang Kexin Zhang Lin Hu Rong Liu Zhibo Ren Jinyi Wang Xiaolong Wang Huaneng Clean energy research Institute Beijing 102209China

Lithium is known as the“white petroleum”of the electrification era,and the global demand for lithium grows rapidly with the quick development of new energy industry.The aqueous solutions,such as salt lake brine,underground brine,and seawater,have large lithium reserves,thus this kind of lithium resource has become a research hotspot recently.Compared with other lithium extraction technologies,electro-sorption method shows good prospects for practical applications with advantages in the aspects of efficiency,recovery ratio,cost,and environment.Herein,this review covers recent progress on electro-sorption technology for lithium recovery from aqueous solutions,including the concept illustration,research progress of the applied working electrodes and counter electrodes,and the evaluation indicators of electro-sorption system.Meanwhile,some prospects for the development of this technology are also proposed.We hope this review is beneficial for the construction of high-efficient electrochemical lithium recovery system to achieve an adequate lithium supply in the future.

关键词： lithium extraction electro-sorption technology lithium selective electrode counter electrode system evaluation method

Anticipating the lifespan: Predicting the durability of an anode-supported solid oxide fuel cell short stack over 50,000 h

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Progress in Natural Science:Materials International 2024年第3期34卷 606-613页

作者： Muhammad Zubair Khan Amjad Hussain Seung-Bok Lee Tak-Hyoung Lim Rak-Hyun Song Department of Materials Science & Engineering Pak-Austria Fachhochschule: Institute of Applied Sciences and Technology Mang Haripur Hydrogen energy research Division Korea Institute of Energy Research Department of Advanced energy and System Engineering Korea University of Science and Technology (UST)

In the present study, the operational lifetime of a solid oxide fuel(SOFC) short stack is predicted by investigating the performance degradation of both the short stack and its cells throughout 1000 h at 800°C. The short stack and integral cell voltages are continuously measured during the long-term test, with electrochemical impedance spectroscopy(EIS) conducted every 200 h. The short stack voltage decreased rapidly for the initial 200–300 h and afterwards, it decreased at a slow rate due to the increase in the Ohmic and polarization resistances in the same manner. Scanning electron microscopy results show that there is no delamination or cracking among constituent layers of the short-stack cells. The single degradation effects of the Ni coarsening in the anode, cation migration and surface segregation in cathode and oxide scale growth in metallic interconnect mesh are successfully integrated into a comprehensive lifetime prediction model. The experimentally measured voltage degradation data of the short stack fits well with the developed mathematical model and allows the successful prediction of the lifetime up to 50,000 h.

关键词： Degradation Impedance Lifetime SOFC Stack

Evaluation of soil loss severity and ecological restoration approach for sustainable agriculture in the Hindu Kush, Karakoram and Himalaya region

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Journal of Mountain Science 2024年第5期21卷 1509-1521页

作者： Arshad ASHRAF Imran AHMAD Climate Energy and Water Research InstituteNational Agricultural Research Centre(NARC)Islamabad 44000Pakistan

Soil erosion has resulted in removal of the topsoils containing fine soil particles and plant nutrients, causing decrease in soil fertility in the Hindu Kush, Karakoram and Himalaya(HKH) region. The existing production of cereal crop grains has been reduced to one third of the potential crop grains production owing to land degradation and poor farming practices. It is necessary to assess risk of soil loss and identify appropriate controlling measures to address issues of low agriculture productivity and water insecurity in the region. In the present study, severity of soil loss was predicted using Revised Universal Loss Equation(RUSLE) and ecological measures were identified for sustainable mountain agriculture in the HKH region of Upper Indus Basin, Pakistan. Overall 62.6% area was found to have very low risk of soil loss, i.e., 100 t/(ha·yr) in about 6.8% and 7.4% areas respectively. The mean rate of soil loss was about 41.9 t/(ha·yr) in the Hindu Kush, 31.1 t/(ha·yr) in the Himalayas, 18.8 t/(ha·yr) in the Karakoram and overall 29.7 t/(ha·yr) in the three HKH ranges. As such no considerable measures have been adopted by the communities for restoration of the degraded areas except raising fruit/farm trees and supporting limited social forestry for their livelihoods. The slopes cleared for cultivation and susceptible to erosion may be stabilized through sowing/planting of multi-purpose plant species and formation of proper bench terraces. The conservation of forest ecosystem and pastures at higher elevations would help in reducing overland water flow, risk of flash flood hazard and minimizing sediment loads in the downstream. It is essential to adopt site-specific resource conservation techniques and restore possible ecosystem health for sustainable agriculture and economic development in the region in future.

关键词： Climate change Erodibility Indus basin Land degradation Slope stabilization

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Numerical study of flow and thermal characteristics of pulsed impinging jet on a dimpled surface

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 106-117页

作者： Amin Bagheri Kazem Esmailpour Morteza Heydari Renewable energy research Center Damavand BranchIslamic Azad UniversityDamavandIran

This research comprehensively investigates the flow and thermal characteristics of a pulsating impinging jet over a dimpled surface.It analyzes the impact of key parameters(e.g.,inlet velocity pulsation functions,pulsation frequency,amplitude,dimple pitch,dimple depth,Reynolds number)on flow patterns and heat transfer.Validated computational fluid dynamics and the Re-normalization group turbulence model are employed to accurately simulate complex turbulent flow behavior.Local and average heat transfer coefficients are calculated and compared to steady impingement cases,revealing the potential benefits of pulsation for heat transfer enhancement.The study also examines how pulsation-induced flow modulation and thermal mixing affect heat transfer mechanisms.Results indicate that combining fluctuating flow with a dimpled surface can improve heat transfer rates.In summary,increasing pulsation amplitude consistently enhances heat transfer,while the effect of frequency varies between impinging and wall jet zones.

关键词： Pulsating impinging jet Dimpled surface Heat transfer enhancement Pulsation frequency and amplitude Coherent structures

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Hole mobility enhancement in monolayer WSe2 p-type transistors through molecular doping

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Science China(Information Sciences) 2024年第6期67卷 207-213页

作者： Shiyuan LIU Xiong XIONG Xin WANG Xinhang SHI Ru HUANG Yanqing WU School of integrated Circuits and Beijing Advanced Innovation Center for integrated Circuits Peking University Wuhan National High Magnetic Field Center and School of integrated Circuits Huazhong University of Science and Technology

Two-dimensional （2D） transition metal dichalcogenide （TMDC） semiconductor materials exhibit extraordinary electrical properties,holding promise for the realization of next-generation complementary metal-oxide-semiconductor （CMOS） devices at ultimate scaling.However,constrained by effective device doping strategies,the hole mobility and device performance of tungsten diselenide （WSe2） p-type transistors,especially monolayer chemical vapor deposition （CVD）-grown WSe2,have not met expectations.In this paper,an effective performance enhancement of monolayer WSe2p-type transistor was achieved through a molecular doping strategy.Synthesizing monolayer WSe2directly on SiO2back-gated substrates and leveraging energy band alignment design,4-nitrobenzenediazonium tetrafluoroborate （4-NBD） molecular dopant with a concentration of 10 m M was utilized to modulate the Fermi level position of monolayer WSe2for hole doping.The devices demonstrated a more than 98%increase in hole mobility,reaching up to 97 cm2·V-1·s-1while maintaining the current on/off ratio of 108.Monolayer p-type WSe2transistors with 1μm channel length exhibit a high drive current surpassing 176μA·μm-1,exceeding previous CVD-WSe2devices with similar channel length.This straightforward and effective approach to improving the electrical performance of WSe2transistors paves the way for advanced logic technologies based on transition metal dichalcogenide semiconductors.

关键词： CVD-grown WSe$_2$ molecular doping 4-NBD p-type transistors hole mobility

Thermal Property Enhancement of a Novel Shape-Stabilized Sodium Acetate Trihydrate-Acetamide/Expanded Graphite-Based Composite Phase Change Material

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Journal of Thermal Science 2024年第4期33卷 1564-1576页

作者： AN Zhoujian HOU Wenjie DU Xiaoze HUANG Zhongzheng MOMBEKI PEA Hamir Johan ZHANG Dong LIU Xiaomin College of energy and Power Engineering Lanzhou University of Technology Key Laboratory of Multi-supply System with Solar energy and Biomass of Gansu Province Gansu Natural energy research Institute

Phase change materials(PCMs) are a kind of highly efficient thermal storage materials which have a bright application prospect in many fields such as energy conservation in buildings,waste heat recovery,battery thermal management and so on.Especially inorganic hydrated salt PCMs have received increasing attention from researchers due to their advantages of being inexpensive and non-flammable.However,inorganic hydrated salt PCMs are still limited by the aspects of inappropriate phase change temperature,liquid phase leakage,large supercooling and severe phase separation in the application process.In this work,sodium acetate trihydrate was selected as the basic inorganic PCM,and a novel shape-stabilized composite phase change material(CPCM) with good thermal properties was prepared by adding various functional additives.At first,the sodium acetate trihydrate-acetamide binary mixture was prepared and the melting point was adjusted using acetamide.Then the binary mixture was incorporated into expanded graphite to synthesize a novel shape-stabilized CPCM.The thermophysical properties of the resultant shape-stabilized CPCM were systematically investigated.The microscopic morphology and chemical structure of the obtained shape-stabilized CPCM were characterized and analyzed.The experiment results pointed out that acetamide could effectively lower the melting point of sodium acetate trihydrate.The obtained shape-stabilized CPCM modified with additional 18%(mass fraction) acetamide and 12%(mass fraction) expanded graphite exhibited good shape stability and thermophysical characteristics:a low supercooling degree of 1.75℃ and an appropriate melting temperature of 40.77℃ were obtained;the latent heat of 151.64 kJ/kg and thermal conductivity of 1.411 W/(m·K) were also satisfactory.Moreover,after 50accelerated melting-freezing cycles,the obtained shape-stabilized CPCM represented good thermal reliability.

关键词： sodium acetate trihydrate melting point modification agent expanded graphite shape stability thermal conductivity enhancement