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Influences of Co-Flow and Counter-Flow Modes of Reactant Flow Arrangement on a PEMFC at Start-Up

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1337-1356页

作者： Qianqian Shao Min Wang nuo Xu School of Petroleum Engineering Guangdong University of Petrochemical TechnologyMaoming525000China Mechanics Division Beijing Computational Science Research CenterBeijing100193China

To investigate the influences of co-flowand counter-flowmodes of reactant flowarrangement on a proton exchange membrane fuel cell(PEMFC)during start-up,unsteady physical and mathematical models fully coupling the flow,heat,and electrochemical reactions in a PEMFC are *** continuity equation and momentum equation are solved by handling pressure-velocity coupling using the SIMPLE *** electrochemical reaction rates in the catalyst layers(CLs)of the cathode and anode are calculated using the Butler-Volmer *** multiphase mixture model describes the multiphase transport process of gas mixtures and liquid water in the fuel *** validation,the influences of co-flow and counter-flow modes on the PEMFC performance are investigated,including the evolution of the current density,flow field,temperature field,and reactant concentration field during start-up,as well as the steady distribution of the current density,reactant concentration,andmembrane water content when the start-up ***-flow and counter-flow modes influence the current density distribution and temperature *** the one hand,the co-flow mode accelerates the start-up process of the PEMFC and leads to a more evenly distributed current density than the counter-flow *** the other hand,the temperature difference between the inlet and outlet sections of the cell is up to 1..1. under the co-flow mode,much larger than the 5.0℃ observed in the counter-flow ***,the counter-flowmode results in a more evenly distributed temperature and a lower maximum temperature than the co-flow ***,in the flow field design of a PEMFC,the reactant flow arrangements can be considered to weigh between better heat management and higher current density distribution of the cell.

关键词： PEMFC full coupling model Butler-Volmer equation multiphase mixture model co-flow mode counter-flow mode

Fault Estimation for a Class of Markov Jump Piecewise-Affine Systems: Current Feedback Based Iterative Learning Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 418-429页

作者： Yanzheng Zhu nuo Xu Fen Wu Xinkai Chen Donghua Zhou IEEE College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China College of Mechanical Engineering and Automation Huaqiao UniversityXiamen 361021China Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleigh NC 27695 USA Department of Electronic and Information Systems Shibaura Institute of TechnologySaitama 337-8570Japan

In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a novel mode-dependent PWA iterative learning observer with current feedback is designed to estimate the system states and faults, simultaneously, which contains both the previous iteration information and the current feedback mechanism. The auxiliary feedback channel optimizes the response speed of the observer, therefore the estimation error would converge to zero rapidly. Then, sufficient conditions for stochastic stability with guaranteed performance are demonstrated for the estimation error system, and the equivalence relations between the system information and the estimated information can be established via iterative accumulating ***, two illustrative examples containing a class of tunnel diode circuit systems are presented to fully demonstrate the effectiveness and superiority of the proposed iterative learning observer with current feedback.

关键词： Current feedback fault estimation iterative learning observer Markov jump piecewise-affine system

Design and Implementation of a Time Synchronization Method for UOWC Networks

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Journal of Communications and Information Networks 2024年第1期9卷 56-63页

作者： Weijie Liu Jingyi Zhang nuo Huang Zhengyuan Xu CAS Key Laboratory of Wireless-Optical Communications School of Information Science and TechnologyUniversity of Science and Technology of ChinaHefei 230027China

Underwater optical wireless communication (UOWC) technology facilitates high-speed data transmission among multiple nodes in underwater networks. Nevertheless, the absence of a common clock poses a challenge to achieving systematic and reliable access for multiple nodes within these networks. This paper presents a time synchronization method for UOWC networks to ensure the successful execution of the media access control (MAC) protocol. In this method, the node obtains timestamps by exchanging messages with the optical access point (OAP). Subsequently, the node calculates the clock drift relative to the OAP and the propagation time,ensuring that transmitted data packets can arrive approximately at the time specified by the OAP. To validate the effect of the proposed method, an experimental UOWC prototype, including the OAP and nodes, is implemented using field programmable gate array (FPGA). The experimental results demonstrate that the maximum difference between the actual arrival times of two data packets that are expected to reach the OAP simultaneously according to the MAC protocol meets the requirements of the quasi-synchronous code division multiple access (QS-CDMA) system, thereby substantiating the effectiveness of this synchronization method.

关键词： UOWC time synchronization MAC FPGA QS-CDMA

Corrosion behaviors and kinetics of nanoscale zero-valent iron in water:A review

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Journal of Environmental Sciences 2024年第1期135卷 391-406页

作者： Chenliu Tang Xingyu Wang Yufei Zhang nuo Liu Xiang Hu Research Group of Water Pollution Control and Water Reclamation College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Shanghai Collaborative Innovation Centre for WEEE Recycling School of Resources and Environmental EngineeringShanghai Polytechnic UniversityShanghai 201209China

Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing theoretical guidance for developing a cost-effective nZVI-based technology and designing large-scale ***,this review gives a holistic overview on the corrosion behaviors and kinetics of nZVI in ***,Eh-pH diagram is introduced to predict the thermodynamics trend of iron *** morphological,structural,and compositional evolution of(modified-)nZVI under different environmental conditions,assisted with microscopic and spectroscopic evidence,is then ***,common analytical methods and characterization technologies are categorized to establish time-resolved corrosion kinetics of nZVI in ***,stable models for calculating the corrosion rate constant of nZVI as well as electrochemical methods for monitoring the redox reaction are discussed,emphasizing their capabilities in studying the dynamic iron corrosion ***,in the future,more efforts are encouraged to study the corrosion behaviors of nZVI in long-term practical application and further build nanoparticles with precisely tailored *** expect that our work can deepen the understanding of the nZVI chemistry in aquatic environment.

关键词： Nanoscale zero-valent iron(nZVI) Corrosion behaviors Corrosion kinetics nZVI evolution

Facile synthesis of a tumor microenvironment-responsive nanomaterial with metallic polyphenol-encapsulated for enhanced synergistic therapy

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Journal of Rare Earths 2024年第10期42卷 1895-1902页

作者： Kaige Yu nuo Kou Shouqiang Zhang Tianqi Cao Hanqing Wu Jing Zhou Department of Chemistry Capital Normal University College of Teacher Education Capital Normal University

The tumor microenvironment（TME） differs from normal tissue cells in its physiological and biochemical *** construction of TME-responsive nanoplatforms requires a tedious preparation process and complex multicomponent *** this work,Er@EGCG-Cu,a TME-responsive nanoplatform,was simply and rapidly synthesized by combining rare earth-doped nanomaterials（NaLuF4:Yb,Er） with EGCG-Cu which is based on the ability of metal ions to coordinate with polyphenols to form a metal-phenolic network（MPN） *** MPN structure is then destroyed under an acidic TME,releasing the chemotherapy（CT） drug EGCG,which can cause apoptosis,CuxSyis generated by combining Cu2+with H2S overexpressed in human colorectal cancer cells and can be used for photothermal therapy（PTT）.Cell experiments show that laser irradiation improves the CT/PTT synergistic effect of Er@*** study has significance for the construction of TME-responsive nanomedicines with simple and rapid preparation for synergistic therapy.

关键词： Metal-polyphenol networks Nanomaterials Rare earths Synergistic therapy Tumor microenvironment

Oils with different degree of saturation:effects on ileal digestibility of fat and corresponding additivity and bacterial community in growing pigs

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Journal of Animal Science and Biotechnology 2024年第4期15卷 1657-1668页

作者： Lu Wang Yifan Chen Yuansen Yang nuo Xiao Changhua Lai State Key Laboratory of Animal Nutrition Ministry of Agriculture and Rural Affairs Feed Industry CentreChina Agricultural UniversityNo.2 Yuanmingyuan West RoadHaidian DistrictBeijing 100193China College of Animal Science and Technology Hebei Agricultural UniversityHebei 071000China

Background Oils are important sources of energy in pig *** combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of oil *** experiment was conducted to evaluate the effects of oils with different degree of saturation on the fat digestibility and corresponding additivity and bacterial community in growing *** Eighteen crossbred(Duroc×Landrace×Yorkshire)barrows(initial body weight:29.3±2.8 kg)were surgically fitted with a T-cannula in the distal *** experimental diets included a fat-free basal diet and 5 oil-added *** 5 oil-added diets were formulated by adding 6%oil with different ratio of unsaturated to saturated fatty acids(U:S)to the basal *** 5 oils were palm oil(U:S=1.2),canola oil(U:S=1..0),and palm oil and canola oil were mixed in different proportions to prepare a combination of U:S of 2.5,3.5 and 4.5,*** The apparent and standardized ileal digestibility(AID and SID)of fat and fatty acids increased linearly(P1.:*** AID and SID of fat and fatty acids differed among the dietary treatments(P1.:*** one-slope broken-line analyses for the SID of fat,saturated fatty acids(SFA)and UFA indicated that the breakpoint for U:S of oil was 4.1.(R^(2)=0.89,P1.,2.91.R^(2)=0.98,P1.and 3.84(R^(2)=0.85,P1.,*** determined SID of fat,C1.:1.C1.:2 and UFA in the mixtures was not different from the calculated SID of fat,C1.:1.C1.:2 and ***,the determined SID of C1.:0,C1.:0 and SFA in the mixtures were greater than the calculated SID values(P1.:0,C1.:0 and SFA(P<0.05).

关键词： Additivity Bacterial community Fat and fatty acids Growing pigs Ratio of unsaturated to saturated fatty acids Standardized ileal digestibility

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结构系统广义可靠性及数值仿真

铁道学报 2004年第3期26卷 36-40页

作者：李超王金诺西南交通大学机械工程学院

建立了结构系统广义可靠性分析模型。根据随机变量可能同时具有随机性和模糊性的特点,分别提出了模糊强度—随机应力、随机强度—模糊应力和模糊强度—模糊应力情况下的模糊可靠性分析方法。同时,建立了结构系统为独立单元部件串联或并... 详细信息

建立了结构系统广义可靠性分析模型。根据随机变量可能同时具有随机性和模糊性的特点,分别提出了模糊强度—随机应力、随机强度—模糊应力和模糊强度—模糊应力情况下的模糊可靠性分析方法。同时,建立了结构系统为独立单元部件串联或并联组成的模糊可靠性分析模型。考虑到不同模糊随机变量组合下的可靠性积分一般不存在解析解的情况,提出了用仿真法计算可靠度数值解,并阐述了数值仿真的基本原理和步骤。通过实例介绍了方法的具体运用。

关键词：结构系统模糊变量随机变量模糊可靠性数值仿真

Metal-to-insulator transition in platinum group compounds

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Rare Metals 2024年第8期43卷 3460-3474页

作者： Yu-Xuan Xia Jian-Gang He nuo-Fu Chen Ji-Kun Chen School of New Energy North China Electric Power UniversityBeijing102206China School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China Key Laboratory of Advanced Materials and Devices for PostMoore Chips(Ministry of Education) School of Materials Science and EngineeringJniversity of Science and Technology BeijingBeijing 100083China

The metal-to-insulator transition(MIT) as usually achieved in 3d-orbital transitional metal(TM) compounds opens up a new paradigm in correlated electronics via triggering abrupt variations in their transportation *** to such 3d-orbital TM compounds,the MIT within the platinum group(Pg) element compounds based on the 4d-and 5d-orbital configurations is more complicated,owing to their elevation in the spinorbit coupling and meanwhile weakened intra-atomic Coulomb *** brings in a new freedom to regulate the balance in their metallic or semiconductive orbital configurations,while their MIT properties can be potentially combined with their spintronic properties to enable new electronic ***,we review the electronic transport and MIT behaviors within the existing family of Pg-containing compounds,particularly those showing first-order MIT behaviors that can be useful in correlated *** is also hoped that summarizing the presently reported Pg-containing MIT compounds will lead to the discovery of more new material families and/or new mechanisms associated with the Pg-containing compounds showing MIT properties.

关键词： Metal-to-insulator transition Platinum group compounds Electron correlation Spin-orbital coupling

Targeting Nrf2 signaling in dry eye

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International Journal of Ophthalmology(English edition) 2024年第10期17卷 1911-1920页

作者： Yu-nuo Zhang Wei-Jie Ouyang Jiao-Yue Hu Zu-Guo Liu Xiamen University Affiliated Xiamen Eye Center Fujian Provincial Key Laboratory of Ophthalmology and Visual ScienceFujian Engineering and Research Center of Eye Regenerative MedicineEye Institute of Xiamen UniversitySchool of MedicineXiamen UniversityXiamen 361005Fujian ProvinceChina Department of Ophthalmology the First Affiliated Hospital of University of South ChinaHengyang 421001Hunan ProvinceChina Department of Ophthalmology Xiang’an Hospital of Xiamen UniversityXiamen 361005Fujian ProvinceChina

Dry eye,the most common ocular surface disease,can cause ocular surface tissue damage and discomfort symptoms and seriously affect people’s quality of *** etiology of dry eye is diverse,and its pathogenesis is *** oxidative stress reaction is considered to be among the important factors in the pathogenesis of dry ***,activating the antioxidant system has a potential therapeutic effect on dry *** factor erythroid 2-related factor 2(Nrf2)signaling pathway is considered the most important antioxidant pathway in the *** activation of the Nrf2 signaling pathway and its interaction with other pathways are important mechanisms to prevent the occurrence and development of dry *** review describes the structure and function of Nrf2,summarizes the changes in the oxidative stress response in dry eye,focuses on the potential mechanism of the Nrf2 signaling pathway in the treatment of dry eye,and,finally,summarizes the drugs that activate the Nrf2 signaling pathway in the treatment of dry eye.

关键词： nuclear factor erythroid 2-related factor 2 Keap1 dry eye oxidative stress