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Journal of Thermal Science 2024年第06期33卷 2399-2412页

作者： WAN Jiawei GUO junjun WEI Zhengyun JIANG Xudong liu Zhaohui State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and Technology (HUST) CCRC King Abdullah University of Science and Technology (KAUST)

To improve the NO modelling in turbulent flames,the flamelet/progress variable(FPV) model is extended by introducing NO mass fraction into the progress variable and incorporating an additional NO transport *** sets of flamelet databases are tabulated with progress variables based on major species and NO mass fraction,*** former is used for the acquisition of the main thermochemical variables,while the latter is employed for NO ***,an additional transport equation is solved to obtain the NO mass fraction,with the source term corrected using the scale similarity *** assessments are first conducted on laminar counterflow diffusion flames to identify lookup-related errors and assess the suitability of progress variable *** results show that the progress variables based on major species and NO could correctly describe the main thermochemical quantities and NO-related variables,***,the model is applied to the large eddy simulation(LES) of Sandia *** results indicate that the extended FPV model improves the NO prediction,with a mean error for NO prediction at 55%,significantly lower than those of existing FPV models(130% and 385%).The LES with the extended FPV model quantitatively captures NO suppression in the mid-range of Reynolds numbers from 22 400(Flame D) to 33 600(Flame E),but underestimates the NO suppression at higher Reynolds numbers from 33 600 to 44 800(Flame F).This underprediction is primarily attributed to the underestimation of local extinction levels in flames with high Reynolds numbers.

关键词： flamelet/progress variable model large eddy simulation NO emission Sandia flames

Review on research and development of oxy-coal burner for carbon capture

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Science China(Technological Sciences) 2024年第3期67卷 647-672页

作者： GUO junjun liu JingZhang ZHANG Tai HU Fan LI PengFei liu ZhaoHui ZHENG ChuGuang State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and Technology Wuhan 430074China CCRC King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Kingdom of Saudi Arabia Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China National Key Laboratory of High Efficiency and Low Carbon Utilization of Coal Beijing 100049China Institute of Energy Research Jiangxi Academy of SciencesNanchang 330096China Carbon Neutrality Research Center of Jiangxi Province Nanchang 330096China Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China National Energy Research and Development Center of Clean and Low Carbon Coal-based Power Generation Technologies Wuhan 430074China

In the past two decades, the oxy-fuel combustion of pulverized coal has been extensively developed, leading to the completion of several large industrial pilot oxy-fuel plants worldwide. Various types of oxy-fuel burners have been designed and tested in largescale pilot plants as key components of oxy-fuel combustion. These burners face major challenges in terms of their flame stability because of their decreasing stream momentum ratio and increasing carbon dioxide concentration. However, it offers flexibility in adjusting the oxygen concentration in each burner stream. This study aims to provide a comprehensive review of the state-of-the-art knowledge on oxy-coal burner design and operation in power plants. First, the combustion characteristics under oxy-fuel conditions are briefly introduced. Subsequently, the principal requirements and fundamental parameters of the oxy-coal burners are discussed. The development process of oxy-fuel burners is also presented. Moreover, a compatible design strategy and scaling-up techniques are described for oxy-coal burners developed by the authors over the past ten years. The performances of oxy-coal burners in three large pilot oxy-fuel plants worldwide are summarized and compared. Finally, concluding remarks are provided and potential research needs are suggested.

关键词： carbon capture oxy-fuel combustion oxy-fuel burner pulverized coal compatible design

Overhead-free Noise-tolerant Federated Learning: A New Baseline

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Machine Intelligence Research 2024年第3期21卷 526-537页

作者： Shiyi Lin Deming Zhai Feilong Zhang junjun Jiang Xianming liu Xiangyang Ji Department of Computer Science and Technology Harbin Institute of TechnologyHarbin150000China Department of Automation Tsinghua UniversityBeijing100084China

Federated learning (FL) is a promising decentralized machine learning approach that enables multiple distributed clients to train a model jointly while keeping their data private. However, in real-world scenarios, the supervised training data stored in local clients inevitably suffer from imperfect annotations, resulting in subjective, inconsistent and biased labels. These noisy labels can harm the collaborative aggregation process of FL by inducing inconsistent decision boundaries. Unfortunately, few attempts have been made towards noise-tolerant federated learning, with most of them relying on the strategy of transmitting overhead messages to assist noisy labels detection and correction, which increases the communication burden as well as privacy risks. In this paper, we propose a simple yet effective method for noise-tolerant FL based on the well-established co-training framework. Our method leverages the inherent discrepancy in the learning ability of the local and global models in FL, which can be regarded as two complementary views. By iteratively exchanging samples with their high confident predictions, the two models “teach each other” to suppress the influence of noisy labels. The proposed scheme enjoys the benefit of overhead cost-free and can serve as a robust and efficient baseline for noise-tolerant federated learning. Experimental results demonstrate that our method outperforms existing approaches, highlighting the superiority of our method.

关键词： Federated learning noise-label learning privacy-preserving machine learning edge intelligence distributed machine learning

Phosphorous-doped carbon nanotube/reduced graphene oxide aerogel cathode enabled by pseudocapacitance for high energy and power zinc-ion hybrid capacitors

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Chinese Chemical Letters 2024年第2期35卷 570-576页

作者： junjun Yao Fuzhi Li Ruyi Zhou Chenchen Guo Xinru liu Yirong Zhu Hunan Key Laboratory of Green Metallurgy and New Energy Materials College of Materials and Advanced ManufacturingHunan University of TechnologyZhuzhou 412007China College of packaging and Material Engineering Hunan University of TechnologyZhuzhou 412007China

The design and development of energy storage device with high energy/power density has become a research ***-ion hybrid capacitors(ZHCs)are considered as one of the most promising ***,the application of ZHCs is hindered by their low energy density at high power density due to the unsatisfactory cathode *** this study,a novel 3D phosphorus-doped carbon nanotube/reduced graphene oxide(P-CNT/rGO)aerogel cathode is synthesized through a synergistic modification strategy of CNT insertion and P doping modification combined with 3D porous *** as-obtained P-CNT/rGO aerogel cathode manifests significantly increased surface aera,expanded interlayer spacing,and enhanced pseudocapacitance behavior,thus leading to significantly enhanced specific capacitance and superb ions transport *** as-assembled ZHC based on P-CNT/rGO cathode delivers a superior energy density of 42.2 Wh/kg at an extreme-high power density of 80 kW/kg and excellent cycle ***-depth kinetic analyses are undertaken to prove the enhanced pseudocapacitance behavior and exceptional power output capability of ***,the reaction mechanism of physical and chemical adsorption/desorption of electrolyte ions on the P-CNT/rGO cathode is revealed by systematic ex-situ *** work can provide a valuable reference for developing advanced graphene-based cathode for high energy/power density ZHCs.

关键词： Graphene aerogel Phosphorus doping Pseudocapacitance Zinc-ion hybrid capacitors Energy storage mechanism

Lattice Boltzmann simulation study of anode degradation in solid oxide fuel cells during the initial aging process

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 405-411页

作者： Shixue liu Zhijing liu Shuxing Zhang hao Wu Hydrogen Energy Industrial Technology Innovation Center China Nuclear Power Technology Research InstituteShenzhen 518031China Shenzhen Engineering Research Center for Hydrogen Safety Shenzhen 518031China

For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative ***,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC *** lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was *** samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging *** parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference *** LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged *** microstructural and activity de-gradations are attributed to Ni migration and coarsening.

关键词： solid oxide fuel cell anode degradation focused ion beam-scanning electron microscopy lattice Boltzmann method

Edge effect during microwave plasma chemical vapor deposition diamond-film:Multiphysics simulation and experimental verification

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2287-2299页

作者： Zhiliang Yang Kang An Yuchen liu Zhijian Guo Siwu Shao Jinlong liu junjun Wei Liangxian Chen Lishu Wu Chengming Li Institute of Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China National Key Laboratory of Solid-State Microwave Devices and Circuits The 55th Research Institute of China Electronics Technology Group CorporationNanjing 210016China

This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor *** bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition ***-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision *** spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the *** simulation results reflected the experimental trends *** discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased *** uniformity of film thickness decreased *** Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the ***△h=1-3 mm,all areas in the film ex-hibited compressive stress.

关键词： microwave plasma chemical vapor deposition edge discharge plasma diamond film

Microbes in mass extinction: an accomplice or a savior?

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National Science Review 2024年第1期11卷 12-15页

作者： Genming Luo Deng liu hao Yang State Key Laboratory of Geobiology and Environmental Geology China University of Geosciences (Wuhan)

Microbes include various types of organisms that are invisible to the naked eye,e.g. bacteria, archaea and microeukaryotes. Although the precise number remains largely unknown, microbes are recognized as the unseen majority of our biosphere [1]. As a group of organisms classified by body size, microbes cover a considerable spectrum of metabolisms,

关键词： AFTERMATH

Toxicity mechanisms of photodegraded polyvinyl chloride nanoplastics on pea seedlings

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 111-124页

作者： hao Wu Beibei He Bocheng Chen An liu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Nanoplasctics(NPs),which are very small in particle size,exert toxic effect to ***,compared to original NPs,photodegraded NPs would pose higher *** is because their relatively higher specific surface areas and the presence of additives which can more easily *** original NPs and aged NPs affect plant growth has not been widely *** work chose polyvinyl chloride NPs(PVC-NPs)that were subjected to up to 1000 h UV light radiation to explore the impact of PVC-NPs on the growth of pea seedlings(Pisum Sativum L.).The results indicated the existence of PVC-NPs with longer UV light radiation time and higher concentrations had more negative influences on pea seedlings’growth such as germination rate(decreased by 10.6%–22.5%),stem length(decreased by 2.8%–8.1%),dry weight(decreased by 6.3%–7.1%)and fresh weight(decreased by 6.7%–14.8%).It was also noted that photodegraded PVC-NPs resulted in damage to leaf stomata and roots,hindering photosynthesis and absorption of nutrients and hence the decrease in chlorophyll and soluble sugar *** to transcriptomic investigation results,the presence of aged PVC-NPs primarily influenced protein processing in endoplasmic reticulum(upregulated metabolic pathway)and phenylpropanoid biosynthesis(downregulated metabolic pathway)of pea *** results provide an in-depth understanding of how NPs influence the growth of plants.

关键词： Nanoplasctics Polyvinyl chloride Toxicity mechanisms Plant growth

Enhancing corn stalk-based anaerobic digestion with different types of zero-valent iron added during the acidification stage:Performance and mechanism

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Journal of Environmental Sciences 2024年第11期145卷 64-74页

作者： Xiang liu Yue liu Min Wang Qianzhen Deng hao Yang College of Agricultural Science and Engineering Hohai UniversityNanjing 210098China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution Wenzhou UniversityWenzhou 325035China Anhui Provincial Key Laboratory of Environmental Pollution Control and Resource Reuse Anhui Jianzhu UniversityHefei 230009China

Anaerobic digestion has been defined as a competitive approach to facilitate the recycling of corn ***,few studies have focused on the role of direct interspecies electron transfer(DIET)pathway in the acidification stage under the addition of different particle sizes of zero-valent iron(ZVI).In this study,three types of ZVI,namely iron filings,iron powder and nanoscale iron,were investigated,respectively,to enhance its high-value *** in volatile fatty acids(VFAs)and methane(CH4)production associated with the underlyingmechanisms were emphatically *** indicated that the addition of ZVI could increase the concentration of VFAs,with the most outstanding performance observed with the use of nanoscale ***,the conversion of propionic acid to acetic acid was driven by adding ZVI with no between-group differences in acidizing ***,the substrate was more fully utilized when supplied with iron powder compared with other groups in methanogenic phase,thereby displaying the maximumCH4 yield with a value of 263.1 mL/(g total solids(TS)).However,adding nanoscale iron could signally shorten the digestion time(T80),saving 7 days in comparison to the group of iron powder.

关键词： Zero-valent iron Corn stalk Anaerobic digestion Volatile fatty acids Methane