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Fe-N-C core-shell catalysts with single low-spin Fe(Ⅱ)-N_(4)species for oxygen reduction reaction and high-performance proton exchange membrane fuel cells

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Journal of Energy Chemistry 2024年第6期93卷 538-546,I0013页

作者： Yan Wan Linhui Yu Bingxin Yang Caihong Li Chen fang Wei Guo fang-Xing Xiao Yangming Lin Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen 361021FujianChina CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021FujianChina Fujian Institute of Research on the Structure of Matter Chinese Academy of SciencesFuzhou 350002FujianChina College of Materials Science and Engineering Fuzhou UniversityNew CampusMinhou 350108FujianChina College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117FujianChina

Fe-N-doped carbon materials(Fe-N-C)are promising candidates for oxygen reduction reaction(ORR)relative to Pt-based catalysts in proton exchange membrane fuel cells(PEMFCs).However,the intrinsic contributions of Fe-N_(4)moiety with different chemical/spin states(e.g.D1,D2,D3)to ORR are unclear since various states coexist *** the present work,Fe-N-C core-shell nanocatalyst with single lowspin Fe(Ⅱ)-N_(4)species(D1)is synthesized and identified with ex-situ ultralow temperature Mossbauer spectroscopy(T=1.6 K)that could essentially differentiate various Fe-N_(4)states and invisible Fe-O *** quantifying with CO-pulse chemisorption,site density and turnover frequency of Fe-N-C catalysts reach 2.4×10^(-9)site g^(-1)and 23 e site~(-1)s^(-1)during the ORR,***-wave potential(0.915V_(RHE))of the Fe-N-C catalyst is more positive(approximately 54 mV)than that of Pt/***,we observe that the performance of PEMFCs on Fe-N-C almost achieves the 2025 target of the US Department of Energy by demonstrating a current density of 1.037 A cm^(-2)combined with the peak power density of 0,685 W cm^(-2),suggesting the critical role of Fe(Ⅱ)-N_(4)site(D1).After 500 h of running,PEMFCs still deliver a power density of 1.26 W cm^(-2)at 1.0 bar H_(2)-O_(2),An unexpected rate-determining step is figured out by isotopic labelling experiment and theoretical *** work not only offers valuable insights regarding the intrinsic contribution of Fe-N_(4)with a single spin state to alkaline/acidic ORR,but also provides great opportunities for developing high-performance stable PEMFCs.

关键词： Fuel cells Oxygen reduction reaction Non-platinum group metals(PGMs) Isotopic labelling Active site TOF

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A comparison of statistical learning of naturalistic textures between DCNNs and the human visual hierarchy

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Science China(Technological Sciences) 2024年第8期67卷 2310-2318页

作者： LU XinCheng YUAN ZiQi ZHANG YiChi AI HaiLin CHENG SiYuan GE YiRan fang fang CHEN NiHong Department of Psychological and Cognitive Sciences Tsinghua UniversityBeijing 100084China IDG/McGovern Institute for Brain Research Tsinghua UniversityBeijing 100084China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health Peking UniversityBeijing 100871China Key Laboratory of Machine Perception(Ministry of Education) Peking UniversityBeijing 100871China Peking-Tsinghua Center for Life Sciences Peking UniversityBeijing 100871China IDG/McGovern Institute for Brain Research Peking UniversityBeijing 100871China State Key Laboratory of Brain and Cognitive Science Institute of PsychologyChinese Academy of SciencesBeijing 100101China

The visual system continuously adapts to the statistical properties of the environment. Existing evidence shows a close resemblance between deep convolutional neural networks(CNNs) and primate visual stream in neural selectivity to naturalistic textures above the primary visual processing stage. This study delves into the mechanisms of perceptual learning in CNNs,focusing on how they assimilate the high-order statistics of natural textures. Our results show that a CNN model achieves a similar performance improvement as humans, as manifested in the learning pattern across different types of high-order image statistics. While L2 was the first stage exhibiting texture selectivity, we found that stages beyond L2 were critically involved in learning. The significant contribution of L4 to learning was manifested both in the modulations of texture-selective responses and in the consequences of training with frozen connection weights. Our findings highlight learning-dependent plasticity in the mid-to-high-level areas of the visual hierarchy. This research introduces an AI-inspired approach for studying learning-induced cortical plasticity, utilizing DCNNs as an experimental framework to formulate testable predictions for empirical brain studies.

关键词： CNN perceptual learning naturalistic texture psychophysics

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DL-蛋氨酸及其羟基类似物在单胃动物体内的代谢机制研究进展

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动物营养学报 2010年第1期22卷 18-23页

作者：方正锋张晓玲吴德林燕四川农业大学动物营养研究所雅安625014 四川农业大学生命理学院雅安625014

本文综述了DL-蛋氨酸(DL-MET)和DL-2-羟基-4-(甲硫基)丁酸(DL-HMB)在肠道转化和代谢的机制及其在动物生产中的应用,以便为正确评价DL-MET和DL-HMB的生物学效价和合理使用2种蛋氨酸源提供参考。

关键词： DL-蛋氨酸 DL-2-羟基-4(甲硫基)丁酸转化代谢

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Compatibility evaluation between waterborne epoxy resin and SBR latex modified asphalt emulsion

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第1期11卷 160-171页

作者： Jianhua Yang Zhengqi Zhang Ying fang Key Laboratory for Special Area Highway Engineering of Ministry of Education Chang'an UniversityXi'an 710064China

Good compatibility between waterborne epoxy resin(WER)modifier and styrene-butadiene rubber(SBR)latex modified asphalt emulsion(SBRE)is an essential premise for good pavement performance of WER and SBR latex compositely modified asphalt emulsion(WSAE).This study aims to explore the compatibility between WER modifier and *** achieve the goal,several WER modifiers produced by two methods were first selected to modify SBRE,thus the WSAEs were ***,storage stability and workability of the WSAEs themselves,and high-temperature performance,rheological behavior and temperature sensitivity of their evaporated residues were compared and evaluated via performing a series of experiments,respectively,thus the WER modifier possessing an optimal modification effect was *** show that the storage stability of WSAEs is sensitive to the amount of *** incorporation of 1%WERs by the mass of SBRE improves the storage stability of SBRE,while WERs that exceed 1%weaken its storage *** the WERs reach 3%and 4%,the 5 d storage stability of prepared WSAEs will be beyond the limitation of *** WERs into SBRE negatively affects the workability of SBRE,and the workability of WSAEs is adversely influenced by the WERs content and the storage *** ensure the construction,the WSAEs with 3%and 4%WERs should not be stored for more than 36 h and 48 h,*** WERs effectively improve the high-temperature performance of SBRE residue,especially the 3%***,the WERs notably enhance the rheological property and thermal stability of SBRE *** contrast,the WER modifier produced by chemically modified method has a smaller adverse impact on the storage stability and workability of WSAE,and a larger enhancement on the high-temperature performance,rheological property and thermal stability of SBRE residue,which is thus recommended to modify SBRE.

关键词： Waterborne epoxy resin SBR modified asphalt emulsion Workability Rheological property Temperature sensitivity Compatibility evaluation

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AI enhances drug discovery and development

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National Science Review 2024年第3期11卷 52-54页

作者： fang Bai Shiliang Li Honglin Li Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology ShanghaiTech University Lingang Laboratory Innovation Center for AI and Drug Discovery East China Normal University

The advent of the third wave of artificial intelligence(AI) heralds a new era in drug discovery. AI-powered techniques can be characteristic of identifying features that are difficult for humans to interpret from big ...

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Improved performance of LiMn_(0.8)Fe_(0.2)PO_(4) by addition of fluoroethylene carbonate electrolyte additive

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Chinese Chemical Letters 2024年第6期35卷 229-233页

作者： Guihuang fang Wei Chen Hongwei Yang Haisheng fang Chuang Yu Maoxiang Wu Faculty of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming 650093China Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The addition of electrolyte additives is an effective strategy for tuning the property of the electrolyte to engineer the electrode/electrolyte interface,and there exist obvious discrepancies regarding the effect of fluoroethylene carbonate(FEC)as an electrolyte additive on the performance of *** FEC is introduced into the electrolyte of the LiMn_(0.8)Fe_(0.2)PO_(4)/Li cell and its effect on the properties of the LiMn_(0.8)Fe_(0.2)PO_(4) is *** is found that the addition of FEC in the electrolyte has a positive effect on the performance of the LiMn_(0.8)Fe_(0.2)PO_(4) cathode,which can be attributed to the reduced products generated by the interfacial side-reactions on the LiMn_(0.8)Fe_(0.2)PO_(4) cathode surface and the decreased metal dissolution in the FEC-containing electrolyte,thanks to the higher oxidation resistance of FEC and the easier and stronger binding of FEC and PF_6^(-).

关键词： Lithium-ion batteries LiMn_(0.8)Fe_(0.2)PO_(4) Cathode Electrolyte additives Fluoroethylene carbonate

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Interface engineering enabled sintering-resistant metal nanocatalysts via reverse Ostwald ripening

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Science China Chemistry 2024年第9期67卷 2789-2791页

作者： Ying Sun Wenhui fang Jieshan Qiu Institute of Clean Energy Chemistry Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced Materials of Liaoning ProvinceCollege of ChemistryLiaoning UniversityShenyang 110036China State Key Laboratory of Chemical Resource Engineering College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China

The design and fabrication of advanced nanocatalysts with the high activity,selectivity,and superior durability remains a big challenge in industrial catalysis[1,2].The sintering of nanocatalysts under the thermally and/or chemically triggered conditions is a bottle-neck issue,which seriously decreases the amount of the exposed active sites and changes the original electronic structure of catalysts,resulting in the irreversible catalyst deactivation and high capital and time cost in industrial operation[3].

关键词： durability irreversible catalysis

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Probing the interaction between asphaltene-wax and its effects on the crystallization behavior of waxes in heavy oil via molecular dynamics simulation

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Petroleum Science 2024年第4期21卷 2839-2848页

作者： Yong Hu Xi Lu Hai-Bo Wang Ji-Chao fang Yi-Ning Wu Jian fang Sun SINOPEC Petroleum Exploration and Production Research Institute Shandong Key Laboratory of Oilfield Chemistry School of Petroleum Engineering China University of Petroleum (East China)

High content of asphaltenes and waxes leads to the high pour point and the poor flowability of heavy oil,which is adverse to its efficient development and its transportation in *** the interaction mechanism between asphaltene-wax is crucial to solve these problems,but it is still *** this paper,molecular dynamics simulation was used to investigate the interaction between asphaltenewax and its effects on the crystallization behavior of waxes in heavy *** show that molecules in pure wax are arranged in a paralleled *** wax molecules in heavy oil,which are close to the surface of asphaltene aggregates,are bent and arranged *** the mass fraction of asphaltenes in asphaltene-wax system(ωasp) is 0-25 wt%,the attraction among wax molecules decreases and the bend degree of wax molecules increases with the increase of ω*** ωaspincreases from 0 to 25 wt%,and the attraction between asphaltene-wax is stronger than that among *** causes that the wax precipitation point changes from 353 to 333 *** the ωaspincreases to 50 wt%,wax molecules are more dispersed owing to the steric hindrance of asphaltene aggregates,and the interaction among wax molecules transforms from attraction to *** causes that the ordered crystal structure of waxes can't be formed at normal ***,the asphaltene,with the higher molecular weight or the more hetero atoms,has more obvious inhibition to the formation of wax ***,resins also have an obvious inhibition on the wax crystal due to the formation of asphalteneresin aggregates with a larger *** results reveal the interaction mechanism between asphaltene-wax,and provide useful guidelines for the development of heavy oil.

关键词： Heavy oil Interaction mechanism Asphaltenes Waxes Molecular dynamics

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The Extended Hybrid Carrier-Based Multiple Access Technology for High Mobility Scenarios

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China Communications 2024年第1期21卷 53-68页

作者： Ge Song Xiaojie fang Xuejun Sha School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China

The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering *** this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless *** employing the EHC modulation,a power layered multiplexing framework is realized,which exhibits enhanced interference suppression capability owing to the more uniform energy distribution *** implementation method and advantage mechanism are explicated respectively for the uplink and downlink,and the performance analysis under varying channel conditions is *** addition,considering the connectivity demand,we explore the non-orthogonal multiple access(NOMA)method of the EHC system and develop the EHC sparse code multiple access *** proposed scheme melds the energy spread superiority of EHC with the access capacity of NOMA,facilitating superior support for massive connectivity in high mobility *** results have verified the feasibility and advantages of the proposed *** with existing HC multiple access schemes,the proposed scheme exhibits robust bit error rate performance and can better guarantee multiple access performance in complex scenarios of nextgeneration communications.

关键词： extended hybrid carrier system high mo-Received:Jun.09,2023 Revised:Nov.20,2023 Editor:Yuanwei Liu bility communications multiple access

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Physical informed memory networks for solving PDEs:implementation and applications

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Communications in Theoretical Physics 2024年第2期76卷 51-61页

作者： Jiuyun Sun Huanhe Dong Yong fang College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

With the advent of physics informed neural networks(PINNs),deep learning has gained interest for solving nonlinear partial differential equations(PDEs)in recent *** this paper,physics informed memory networks(PIMNs)are proposed as a new approach to solving PDEs by using physical laws and dynamic behavior of *** the fully connected structure of the PINNs,the PIMNs construct the long-term dependence of the dynamics behavior with the help of the long short-term memory ***,the PDEs residuals are approximated using difference schemes in the form of convolution filter,which avoids information loss at the neighborhood of the sampling ***,the performance of the PIMNs is assessed by solving the Kd V equation and the nonlinear Schr?dinger equation,and the effects of difference schemes,boundary conditions,network structure and mesh size on the solutions are *** show that the PIMNs are insensitive to boundary conditions and have excellent solution accuracy even with only the initial conditions.

关键词： nonlinear partial differential equations physics informed memory networks physics informed neural networks numerical solution

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