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A theoretical study of hydrogen-bonded molecular clusters of sulfuric acid and organic acids with amides

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Journal of Environmental Sciences 2021年第2期33卷 328-339页

作者： Chenpeng Zuo Xianwei Zhao Hetong Wang Xiaohui Ma Siyuan Zheng Fei Xu Qingzhu Zhang Shenzhen Research Institute Shandong UniversityShenzhen 518057China Enuironment research institute Shandong UniversityQingdao 266237China

Amides,a series of significant atmospheric nitrogen-containing volatile organic compounds(VOCs),can participate in new particle formation(NPF)throught interacting with sulfuric acid(SA)and organic acids.In this study,we investigated the molecular interactions of formamide(FA),acetamide(AA),N-methylformamide(MF),propanamide(PA),Nmethylacetamide(MA),and N,N-dimethylformamide(DMF)with SA,acetic acid(HAC),propanoic acid(PAC),oxalic acid(OA),and malonic acid(MOA).Global minimum of clusters were obtained through the association of the artificial bee colony(ABC)algorithm and density functional theory(DFT)calculations.The conformational analysis,thermochemical analysis,frequency analysis,and topological analysis were conducted to determine the interactions of hydrogen-bonded molecular clusters.The heterodimers formed a hepta or octa membered ring through four different types of hydrogen bonds,and the strength of the bonds are ranked in the following order:SO-H···O>CO-H···O>N-H···O>C-H···O.We also evaluated the stability of the clusters and found that the stabilization effect of amides with SA is weaker than that of amines with SA but stronger than that of ammonia(NH 3)with SA in the dimer formation of nucleation process.Additionally,the nucleation capacity of SA with amides is greater than that of organic acids with amides.

关键词： Amides Sulfuric acid Organic acids Hydrogen bond Nucleation

Engineering nanoporous and solid core-shell architectures of lowplatinum alloy catalysts for high power density PEM fuel cells

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Nano research 2022年第7期15卷 6148-6155页

作者： Yongqiang Kang Jiaqi Wang Yinping Wei Yongle Wu Dongsheng Xia Lin Gan institute of Materials research Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

Low-platinum(Pt)alloy catalysts hold promising application in oxygen reduction reaction(ORR)electrocatalysis of protonexchange-membrane fuel cells(PEMFCs).Although significant progress has been made to boost the kinetic ORR mass activity at low current densities in liquid half-cells,little attention was paid to the performance of Pt-based catalysts in realistic PEMFCs particularly at high current densities for high power density,which remains poorly understood.In this paper,we show that,regardless of the kinetic mass activity at the low current density region,the high current density performance of the low-Pt alloy catalysts is dominantly controlled by the total Pt surface area,particularly in low-Pt-loading H_(2)–air PEMFCs.To this end,we propose two different strategies to boost the specific Pt surface area,the post-15-nm dealloyed nanoporous architecture and the sub-5-nm solid core–shell nanoparticles(NPs)through fluidic-bed synthesis,both of which bring in comparably high mass activity and high Pt surface area for large-current-density performance.At medium current density,the dealloyed porous NPs provide substantially higher H_(2)–air PEMFC performance compared to solid core–shell catalysts,despite their similar mass activity in liquid half-cells.Scanning transmission electron microscopy images combined with electron energy loss spectroscopic imaging evidence a previously unreported“semi-immersed nanoporous-Pt/ionomer”structure in contrast to a“fully-immersed core–shellPt/ionomer”structure,thus favoring O_(2) transport and improving the fuel cell performance.Our results provide new insights into the role of Pt nanostructures in concurrently optimizing the mass activity,Pt surface area and Pt/Nafion interface for high power density fuel cells.

关键词： low-platinum alloy catalyst nanoporosity proton-exchange-membrane fuel cells power density triple-phase boundary

Review of In‑Vehicle Optical Fiber Communication Technology

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Automotive Innovation 2022年第3期5卷 272-284页

作者： Wenwei Wang Shiyao Yu Wanke Cao Kaidi Guo National Engineering research Center of Electric Vehicles Beijing Institute of Technology(BIT)BeijingChina shenzhen Automotive research institute Beijing Institute of Technology(BIT)ShenzhenChina

With the continuous development of automotive intelligent networking and autonomous driving technologies,the number of in-vehicle electronic systems and applications is increasing rapidly.This change increases the amount of data to be transmitted in the vehicle and puts forward further requirements of higher speed and safety for in-vehicle communication.Traditional vehicle bus technologies are no longer sufficient to meet today’s high-speed transmission requirements,in which copper cables are used extensively,resulting in serious electromagnetic interference(EMI).Vehicle optical fiber communication technology,besides greatly improving the data transmission rate,has the advantages of anti-EMI,reducing cable space and vehicle mass.This paper first presents the motivation of applying vehicle optical fiber communication technology and reviews the development history of vehicle optical fiber communication technology.Then,the paper researches the devel-opment trend of automotive electrical and electronic architecture(EEA),from distributed EEA to domain centralized EEA and zone-oriented EEA.Based on the discussion of the development trend of automotive EEA,an EEA based on vehicle optical fiber communication technology is proposed.Finally,the key points and future directions of vehicle optical fiber communication technology research are highlighted,including vehicle multi-mode optical fiber technology,vehicle optical fiber network protocol,and topology.

关键词： In-vehicle network Optical fiber communication Multi-mode optical fiber Electrical and electronic architecture

THz Wave Detection of Gap Defects Based on a Convolutional Neural Network Improved by a Residual Shrinkage Network

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CSEE Journal of Power and Energy Systems 2023年第3期9卷 1078-1089页

作者： Zhonghao Zhang Guozheng Peng Yuanpeng Tan Tianjiao Pu Liming Wang China Electric Power research institute Tsinghua shenzhen International Gradual School Shenzhen 518055China

Internal air gap is a serious type of defect in the insulation equipment,which threatens the safe operation of the power grid.In order to diagnose the position and thickness of the internal air gap,this paper proposes a terahertz wave detection method based on wavelet analysis and a CNN(convolution neural network)model.According to the time-frequency characteristics of the wavelet cluster,the calculation method of air gap depth is proposed.To determine the thickness of the internal air gap,the performances of several classification methods,such as waveform feature analysis,Bayes,MLP(Multi-layer Perceptron),SVM(Support Vector Machine)and CNN are compared.The results show that the CNN modified by a residual shrinkage network and SVM(CNN-RSN-SVM)has the best performance.By adjusting the parameters,the classification accuracy of the CNN-RSN-SVM model can be elevated to 98.91%.Furthermore,the 3D imaging method of air gap defect based on wavelet analysis and CNNRSN-SVM classification model is formed.

关键词： Convolutional neural network defect detection insulation equipment terahertz wave

A Fully Actuated System Approach for Stabilization of Discrete-Time Multiple-Input Nonlinear Systems with Distinct Input Delays

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Journal of Systems Science & Complexity 2022年第2期35卷 670-687页

作者： WU Ai-Guo ZHANG Jie JI Youzhou Harbin institute of Technology(shenzhen) Shenzhen 518055China HIT Wuhu Robot Technology research institute Wuhu 241008China

In this paper,the problem of stabilization is considered for discrete-time multiple-input nonlinear systems with distinct input delays law based on the fully actuated system approach.In order to compensate the input delays,a prediction scheme is presented to predict future states based on the closed-loop linear system.Then,a stabilizing law is constructed for nonlinear delayed systems by replacing the future states in the control law for the corresponding delay-free systems with their prediction.Finally,numerical examples are given to verify the effectiveness of the proposed approach.

关键词： Fully actuated system approach input delays nonlinear systems prediction scheme

Modulation of Neuronal Activity and Saccades at Theta Rhythm During Visual Search in Non-human Primates

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Neuroscience Bulletin 2022年第10期38卷 1183-1198页

作者： Jin Xie Ting Yan Jie Zhang Zhengyu Ma Huihui Zhou The Brain Cognition and Brain Disease institute Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research InstitutionsShenzhen518055China University of Chinese Academy of Sciences Beijing100049China The research Center for Artificial Intelligence Peng Cheng LaboratoryShenzhen518000China

Active exploratory behaviors have often been associated with theta oscillations in rodents,while theta oscillations during active exploration in non-human primates are still not well understood.We recorded neural activities in the frontal eye field(FEF)and V4 simultaneously when monkeys performed a free-gaze visual search task.Saccades were strongly phase-locked to theta oscillations of V4 and FEF local field potentials,and the phase-locking was dependent on saccade direction.The spiking probability of V4 and FEF units was significantly modulated by the theta phase in addition to the time-locked modulation associated with the evoked response.V4 and FEF units showed significantly stronger responses following saccades initiated at their preferred phases.Granger causality and ridge regression analysis showed modulatory effects of theta oscillations on saccade timing.Together,our study suggests phase-locking of saccades to the theta modulation of neural activity in visual and oculomotor cortical areas,in addition to the theta phase locking caused by saccade-triggered responses.

关键词： Visual search Saccade Theta rhythm FEF V4 Non-human primate

Progress on metal-support interactions in Pd-based catalysts for automobile emission control

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Journal of Environmental Sciences 2023年第3期125卷 401-426页

作者： Yidan Cao Rui Ran Xiaodong Wu Zhichun Si Feiyu Kang Duan Weng institute of Materials research Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Tsinghua-Berkeley shenzhen institute Tsinghua UniversityShenzhen 518055China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The interactions between metals and oxide supports,so-called metal-support interactions(MSI),are of great importance in heterogeneous catalysis.Pd-based automotive exhaust control catalysts,especially Pd-based three-way catalysts (TWCs),have received considerable research attention owing to its prominent oxidation activity of HCs/CO,as well as excellent thermal stability.For Pd-based TWCs,the dispersion,chemical state and thermal stability of Pd species,which are crucial to the catalytic performance,are closely associated with interactions between metal nanoparticles and their supporting matrix.Progress on the research about MSI and utilization of MSI in advanced Pd-based three-way catalysts are reviewed here.Along with the development of advanced synthesis approaches and engine control technology,the study on MSI would play a notable role in further development of catalysts for automobile exhaust control.

关键词： Palladium Three-way catalysts(TWCs) Metal-support interaction Oxide supports

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 analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical 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 cell.The 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 cell.The 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

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基于二维晶体的阻变实现非马尔可夫过程

Science Bulletin 2021年第16期66卷 1634-1640,M0003页

作者：张荣杰陈文骏滕长久廖武刚刘碧录成会明 shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen Institute and Institute of Materials ResearchTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China institute of Microscale Optoelectronics Shenzhen UniversityShenzhen 518060China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

在大数据时代,具有历史累积效应的非马尔可夫链算法显得尤为重要,如与记忆相关的人类脑神经、与环境相关的量子纠缠态和机器视觉追踪算法等.在传统的器件结构中,需通过大量晶体管和存储器的协同作用才能实现这类功能.基于二维材料的电... 详细信息

在大数据时代,具有历史累积效应的非马尔可夫链算法显得尤为重要,如与记忆相关的人类脑神经、与环境相关的量子纠缠态和机器视觉追踪算法等.在传统的器件结构中,需通过大量晶体管和存储器的协同作用才能实现这类功能.基于二维材料的电阻随机存取存储器(RRAM)在下一代计算系统中已显示出巨大的应用潜力,为非马尔可夫链的简易实现提供了解决方案.本文发现二维云母片是一种良好的离子导体,其内部的钾离子可在外加电场的驱动下定向移动,使云母表现出阻变特征.进一步研究发现云母RRAM兼具单、双存储窗口,高开关比,良好的稳定性和重复性等优点.基于云母RRAM首次在单个存储器件中实现了非马尔可夫过程,其输出状态既取决于当前输入电压的极性,也取决于之前所施加电压的极性.本文利用RRAM器件中导电离子的极性在硬件系统中实现了非马尔可夫过程,对未来人工智能和大数据算法等领域的发展具有一定意义.

关键词：非马尔可夫过程存储器件人工智能追踪算法机器视觉马尔可夫链输出状态定向移动