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High-performance nickel metal hydride battery anode with enhanced durability and excellent low-temperature discharge capability

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Nano Research 2024年第10期17卷 8819-8825页

作者： Zhitao Chen Huitian liu Jean Nei Nian liu School of Chemical and Biomolecular Engineering Georgia Institute of TechnologyAtlantaGA 30332USA GP Batteries HongkongChina

Current AB_(5)-type hydrogen storage alloys employed in nickel-metal hydride(NiMH)batteries exhibit exceptional low-temperature discharge performance but suffer from limited cycle life and insufficient high-temperature *** overcome these challenges,we introduce a hydrothermal synthesized LaF_(3)coating layer on the surface of the AB_(5)anode *** LaF_(3)coating layer adds a protective barrier for the active material,significantly improving the battery's cycle life and high-temperature *** findings indicate that(1)the LaF_(3)coated anode demonstrates an extended cycle life with increased specific capacity and a capacity retention of 88%after 40 cycles of abusive overcharging and rapid discharging at room temperature.(2)The synthesized anode exhibits a 97%recovery of its specific capacity of 292.7 mAh/g following 144 h of high-temperature storage.(3)The low-temperature discharge capacity of the synthesized anode remains on par with the pristine AB_(5)alloy at 230.4 mAh/g in a-40℃*** research presents a significant advancement in hydrogen storage alloy coatings and offers valuable insights for designing electrodes in NiMH batteries.

关键词： nickel metal hydride(NiMH)batteries hydrothermal synthesis lanthanum fluoride discharge capacity low temperature

Performance analysis and multi-objective optimization based on a modified irreversible Stirling cycle

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Science China(Technological Sciences) 2024年第6期67卷 1668-1684页

作者： XU Lei YU MinJie liu ZhiChun liu Wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China

The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle *** obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accurate heat transfer process in Stirling engines based on a thermodynamic function called available *** finite-time thermodynamic method is used to analyze the model performance under constant heat source temperature,finite temperature difference heat transfer,and incomplete regenerative processes.A new polytropic process is introduced to model the heat transfer between the working fluid and external heat sources in which only heat above ambient temperature is converted into technical *** regenerator is divided into numerous smaller heat reservoirs with individual temperature to analyze the incomplete regenerative *** expressions of the output power and thermal efficiency are obtained based on the modified irreversible Stirling cycle,and the effects of irreversible losses are analyzed to evaluate the performance of the proposed *** indicate that the efficiency of the modified cycle is much lower than that of the ideal Stirling cycle with an isothermal *** the increase of the average heat transfer temperature difference,there exists an optimum value for the power of the irreversible *** optimum power of the model was obtained for varying thermodynamic parameters by optimizing the average heat transfer temperature difference between the hot and cold *** optimize the irreversible model,the multi-objective optimization analysis is carried out based on NSGA-Ⅱ,which results in an optimized output power of 40.87 kW and an optimized thermal efficiency of 44%.

关键词： stirling cycle regenerative processes isopotential processes multi-objective optimization finite time thermodynamics

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胡萝卜片中富集植物乳杆菌的工艺优化

食品科学 2017年第16期38卷 183-189页

作者：崔莉牛丽影黄家鹏李大婧张钟元刘春菊刘春泉刘莹萍肖丽霞江苏省农业科学院农产品加工研究所江苏南京210014 扬州大学食品科学与工程学院江苏扬州225127

为将植物乳杆菌富集到胡萝卜中以制备含益生菌的果蔬功能食品,本研究首先通过单因素和正交试验优化植物乳杆菌以真空浸渍和超声浸渍的方式富集到胡萝卜片中的工艺参数,然后以常压浸渍为对照比较3种浸渍方式下胡萝卜片中富集的活菌数,以... 详细信息

为将植物乳杆菌富集到胡萝卜中以制备含益生菌的果蔬功能食品,本研究首先通过单因素和正交试验优化植物乳杆菌以真空浸渍和超声浸渍的方式富集到胡萝卜片中的工艺参数,然后以常压浸渍为对照比较3种浸渍方式下胡萝卜片中富集的活菌数,以期获得较优的胡萝卜植物乳杆菌富集方式。结果表明,真空浸渍较优工艺参数为真空浸渍温度35℃、真空浸渍时间15 min、复压浸渍时间20 min;超声浸渍较优工艺参数为超声浸渍温度30℃、超声浸渍功率125 W、超声浸渍时间12 min。比较真空浸渍、超声浸渍和常压浸渍3种方式下胡萝卜中活菌数可知,真空浸渍组活菌数最多,达到10^(10) CFU/g以上;扫描电子显微镜结果显示,在真空和超声浸渍的胡萝卜组织中均观察到杆状菌体,而在常压浸渍样品的组织内部未发现菌体。3种浸渍方式下胡萝卜组织表面均有大量菌体。本研究获得了较优的胡萝卜中富集植物乳杆菌工艺参数,为乳酸菌或其他菌通过真空浸渍富集到果蔬组织中提供实验依据,也为含益生菌功能食品开发提供新思路。

关键词：益生菌胡萝卜片真空浸渍超声浸渍

Foundation models meet visualizations: Challenges and opportunities

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Computational Visual Media 2024年第3期10卷 399-424页

作者： Weikai Yang Mengchen liu Zheng Wang Shixia liu School of Software Tsinghua UniversityBeijing 100084China Microsoft Redmond 98052USA

Recent studies have indicated that foundation models, such as BERT and GPT, excel atadapting to various downstream tasks. This adaptability has made them a dominant force in buildingartificial intelligence (AI) systems. Moreover, a newresearch paradigm has emerged as visualizationtechniques are incorporated into these models. Thisstudy divides these intersections into two researchareas: visualization for foundation model (VIS4FM)and foundation model for visualization (FM4VIS).In terms of VIS4FM, we explore the primary roleof visualizations in understanding, refining, and evaluating these intricate foundation models. VIS4FMaddresses the pressing need for transparency, explainability, fairness, and robustness. Conversely, in termsof FM4VIS, we highlight how foundation models canbe used to advance the visualization field itself. Theintersection of foundation models with visualizations ispromising but also introduces a set of challenges. Byhighlighting these challenges and promising opportunities, this study aims to provide a starting point forthe continued exploration of this research avenue.

关键词： visualization artificial intelligence(AI) machine learning foundation models visualization for foundation model(VIS4FM) foundation model for visualization(FM4VIS)

Automated,economical,and environmentally-friendly asphalt mix design based on machine learning and multi-objective grey wolf optimization

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 381-405页

作者： Jian liu Fangyu liu Linbing Wang Department of Civil and Environmental Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA School of Environmental CivilAgricultural and Mechanical EngineeringUniversity of GeorgiaAthensGA 30602USA Illinois Center for Transportation Department of Civil and Environmental EngineeringUniversity of Illinois Urbana-ChampaignUrbanaIL 61801USA

The increasing impact of the greenhouse effect on ecosystems is prompting transportation agencies to seek methods for reducing CO_(2)emissions during pavement construction and ***,the laboratory mix design process,which involves selecting aggregate gradation and binder content,is time-consuming and *** accelerate the traditional mix design procedure,this study presented a mix design procedure that can automatically determine gradation and binder content based on machine learning(ML)and a meta-heuristic ***,ML approaches were employed to model the relationship between volumetric properties(mixture bulk specific gravity(Gmb)and air void(VV))and both mixture component properties and mixture proportion,based on a dataset collected from literature with 660 mixture *** with the prediction of ML models and the modified multi-objective grey wolf optimization(MOGWO)algorithm,an automatic asphalt mix design was proposed to pursue three goals,including VV,cost,and CO_(2)*** results indicated that least squares support vector regression(LSSVR)and e Xtreme gradient boosting(XGBoost)achieved the highest prediction accuracies(correlation coefficient:0.92 for VV and 0.96 for Gmb).The MOGWO algorithm successfully found the 26 optimal mix designs for the case of VV *** ***_(2)*** to the traditional laboratory design,the optimal mixture with VV of4%achieves a cost saving of 2.46%and a reduction of 4.03%in carbon *** volumetric properties of the mixtures output by the approach also align closely with values measured in a laboratory.

关键词： Asphalt mix design Machine learning MOGWO CO_(2)emission Volumetric properties

Mg-doped,carbon-coated,and prelithiated SiO_(x) as anode materials with improved initial Coulombic efficiency for lithium-ion batteries

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Carbon Energy 2024年第3期6卷 204-214页

作者： Bin liu Jie liu Cheng Zhong Wenbin Hu Key Laboratory of Advanced Ceramics and Machining Technology(Ministry of Education) School of Materials Science and EngineeringTianjin UniversityTianjinChina Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjinChina Joint School of National University of Singapore and Tianjin University TianjinChina International Campus of Tianjin University Binhai New CityFuzhouChina

Silicon suboxide(SiO_(x),x≈1)is promising in serving as an anode material for lithium-ion batteries with high capacity,but it has a low initial Coulombic efficiency(ICE)due to the irreversible formation of lithium silicates during the first *** this work,we modify SiO_(x) by solid-phase Mg doping reaction using low-cost Mg powder as a reducing *** show that Mg reduces SiO_(2) in SiO_(x) to Si and forms MgSiO_(3) or Mg_(2)SiO_(4).The MgSiO_(3) or Mg_(2)SiO_(4) are mainly distributed on the surface of SiO_(x),which suppresses the irreversible lithium-ion loss and enhances the ICE of SiO_(x).However,the formation of MgSiO_(3) or Mg_(2)SiO_(4) also sacrifices the capacity of SiO_(x).Therefore,by controlling the reaction process between Mg and SiO_(x),we can tune the phase composition,proportion,and morphology of the Mg-doped SiO_(x) and manipulate the *** obtain samples with a capacity of 1226 mAh g^(–1) and an ICE of 84.12%,which show significant improvement over carbon-coated SiO_(x) without Mg *** the synergistical modification of both Mg doping and prelithiation,the capacity of SiO_(x) is further increased to 1477 mAh g^(–1) with a minimal compromise in the ICE(83.77%).

关键词： initial Coulombic efficiency lithium-ion batteries magnesium doping prelithiation silicon suboxide

Improved Double Deep Q Network-Based Task Scheduling Algorithm in Edge Computing for Makespan Optimization

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Tsinghua Science and Technology 2024年第3期29卷 806-817页

作者： Lei Zeng Qi liu Shigen Shen Xiaodong liu School of Computer Science Nanjing University of Information Science and TechnologyNanjing 210044China School of Software Nanjing University of Information Science and TechnologyNanjing 210044China School of Information Engineering Huzhou UniversityHuzhou 313000China School of Computing Edinburgh Napier UniversityEdinburghEH105DTUK

Edge computing nodes undertake an increasing number of tasks with the rise of business ***,how to efficiently allocate large-scale and dynamic workloads to edge computing resources has become a critical *** study proposes an edge task scheduling approach based on an improved Double Deep Q Network(DQN),which is adopted to separate the calculations of target Q values and the selection of the action in two networks.A new reward function is designed,and a control unit is added to the experience replay unit of the *** management of experience data are also modified to fully utilize its value and improve learning *** learning agents usually learn from an ignorant state,which is *** such,this study proposes a novel particle swarm optimization algorithm with an improved fitness function,which can generate optimal solutions for task *** optimized solutions are provided for the agent to pre-train network parameters to obtain a better cognition *** proposed algorithm is compared with six other methods in simulation *** show that the proposed algorithm outperforms other benchmark methods regarding makespan.

关键词： edge computing task scheduling reinforcement learning makespan Double Deep Q Network(DQN)

Localization−delocalization transitions in non-Hermitian Aharonov−Bohm cages

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Frontiers of physics 2024年第3期19卷 39-50页

作者： Xiang Li Jin liu Tao liu School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

A unique feature of non-Hermitian systems is the extreme sensitivity of the eigenspectrum to boundary conditions with the emergence of the non-Hermitian skin effect (NHSE). A NHSE originates from the point-gap topology of complex eigenspectrum, where an extensive number of eigenstates are anomalously localized at the boundary driven by nonreciprocal dissipation. Two different approaches to create localization are disorder and flat-band spectrum, and their interplay can lead to the anomalous inverse Anderson localization, where the Bernoulli anti-symmetric disorder induces mobility in a full-flat band system in the presence of Aharonov−Bohm (AB) Cage. In this work, we study the localization−delocalization transitions due to the interplay of the point-gap topology, flat band and correlated disorder in the one-dimensional rhombic lattice, where both its Hermitian and non-Hermitian structures show AB cage in the presence of magnetic flux. Although it remains the coexistence of localization and delocalization for the Hermitian rhombic lattice in the presence of the random anti-symmetric disorder, it surprisingly becomes complete delocalization, accompanied by the emergence of NHSE. To further study the effects from the Bernoulli anti-symmetric disorder, we found the similar NHSE due to the interplay of the point-gap topology, correlated disorder and flat bands. Our anomalous localization−delocalization property can be experimentally tested in the classical physical platform, such as electrical circuit.

关键词： non-Hermitian skin effects disorder flat band localization−delocalization transition

Construction of Pd-doped RuO_(2) nanosheets for efficient and stable acidic water oxidation

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Green Energy & Environment 2024年第6期9卷 937-948页

作者： Yibo liu Xing Hu Chenxi liu Shan Zhu Kezhu Jiang Feng liu Shijian Zheng Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology College of Materials Science and EngineeringHebei University of TechnologyTianjin300401China Yunnan Precious Metals Lab Co. LTDKunming650100China

RuO_(2) has been considered a potential alternative to commercial IrO_(2) for the oxygen evolution reaction(OER)due to its superior intrinsic ***,its inherent structure dissolution in acidic environments restricts its commercial *** this study,we report a novel Pd-doped ruthenium oxide(Pd–RuO_(2))nanosheet catalyst that exhibits improved activity and stability through a synergistic effect of Pd modulation of Ru electronic structure and the two-dimensional *** catalyst exhibits excellent performance,achieving an overpotential of only 204 mVat a current density of 10 mA cm^(-2).Impressively,after undergoing 8000 cycles of cyclic voltammetry testing,the overpotential merely decreased by 5 *** PEM electrolyzer with Pd0.08Ru0.92O_(2) as an anode catalyst survived an almost 130 h operation at 200 mA cm^(-2).To elucidate the underlying mechanisms responsible for the enhanced stability,we conducted an X-ray photoelectron spectroscopy(XPS)analysis,which reveals that the electron transfer from Pd to Ru effectively circumvents the over-oxidation of Ru,thus playing a crucial role in enhancing the catalyst's ***,density functional theory(DFT)calculations provide compelling evidence that the introduction of Pd into RuO_(2) effectively modulates electron correlations and facilitates the electron transfer from Pd to Ru,thereby preventing the overoxidation of ***,the application of the two-dimensional structure effectively inhibited the aggregation and growth of nanoparticles,further bolstering the structural integrity of the catalyst.

关键词： Oxygen evolution reaction Pd-doped ruthenium oxide Two-dimensional structure Electron transfer Stability