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Ethane dehydrogenation over the g-C_(3)N_(4)supported metal singleatom catalysts to enhance reactivity and coking-resistance ability

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Nano Research 2023年第5期16卷 6142-6152页

作者： yuan zhang Baojun Wang Maohong Fan Lixia Ling Riguang zhang College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan 030024China Departments of Chemical and Petroleum Engineering University of WyomingLaramieWY 82071USA School of Civil and Environmental Engineering Georgia Institute of TechnologyAtlantaGA 30332USA School of Energy Resources University of WyomingLaramieWY 82071USA

Ethane dehydrogenation(EDH)to produce ethylene requires high operating temperature to achieve satisfactory ethylene yield,however,this process leads to coke formation and catalyst ***,an active site isolation strategy was employed to inhibit side reaction and coke formation over fifteen types of metal single-atom metal/graphitic carbon nitride(M/g-C_(3)N_(4))*** functional theory(DFT)calculations completely describe reaction network of ethane *** kinetic Monte Carlo simulations were carried out to evaluate catalytic performance under the realistic *** Co/g-C_(3)N_(4),Rh/g-C_(3)N_(4),Ni/g-C_(3)N_(4)catalysts were screened out to exhibit higher C_(2)H_(4)(g)formation activity and C_(2)H_(4)(g)selectivity close to or equal to 100%.The low reactant partial pressure 0%–5%at atmospheric pressure facilitates ethane dehydrogenation,and the appropriate temperatures over Co/g-C_(3)N_(4),Rh/g-C_(3)N_(4),Ni/g-C_(3)N_(4)catalysts are 673.15,723.15,723.15 K,***,Co/g-C_(3)N_(4)catalyst presents the highest C_(2)H_(4)(g)formation activity,attributing to the appropriate antibonding strength between C atom and metal ***,a simple descriptor,the reaction energy of C_(2)H_(5)*dehydrogenation to C_(2)H_(4)*,was proposed to quantitatively and quickly evaluate C_(2)H_(4)(g)formation *** present study laid a solid foundation for efficient design and development of single-atom catalysts with high-performance for selective dehydrogenation of alkanes.

关键词： ethane dehydrogenation single-atom catalyst graphitic carbon nitrides density functional theory(DFT)calculations kinetic Monte Carlo

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Unraveling the condensation reactions of heterometallic {BiNb_(4)} moieties into hybrid Bi_(x)Nb_(y)-oxo clusters with mass spectrometry

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Science China Chemistry 2021年第3期64卷 413-418页

作者： Lv-Bing yuan Ya-Yong Sun Jian zhang Lei zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China

The most effective methodologies for the construction of polynuclear complexes usually take advantage of preorganized building ***,we successfully developed a new versatile heterometallic{BiNb_(4)}moiety,which can be applied for the assembly of less explored organic-inorganic hybrid *** controlled condensation reactions,three{BiNb_(4)}moieties can be assembled into a pair of isomeric Bi_(3)Nb_(18)clusters at different temperatures;whilst four{BiNb_(4)}moieties can be combined into two unique Bi_(4)Nb_(16)and Bi_(4)Nb_(18)tetramers in different ***,we have used mass spectrometry to probe the above condensation reactions,which clearly confirmed a stepwise bottom-up assembly process by capturing the presence of bismuth subsalicylate precursors,salicylate coordinated intermediates,Nb incorporated{BiNb_(4)}moieties and the final Bi_(x)Nb_(y)-oxo clusters,***,the packing modes of the{BiNb_(4)}units induce different solution behaviors,and the{BiNb_(4)}units in Bi4Nb16can be recombined by post-synthetic recrystallization in acetonitrile to produce a new tetramer Bi_(4)Nb_(18)-***,this work provides not only a useful{BiNb_(4)}building unit but also the mechanism for their condensation,both of which will promote the future development of metal-oxo clusters.

关键词： cluster compounds mass spectrometry heterometallic complexes condensation reactions

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Implementation Framework and Validation of Cluster-Nuclei Based Channel Model Using Environmental Mapping for 6G Communication Systems

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China Communications 2022年第4期19卷 1-13页

作者： Li Yu Yuxiang zhang Jianhua zhang Zhiqiang yuan State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

With the research of the upcoming sixth generation(6 G) systems, new technologies will require wider bandwidth, larger scale antenna arrays and more diverse wireless communication scenarios on the future channel modeling. Considering channel model is prerequisite for system design and performance evaluation of 6 G technologies, we face a challenging task: how to accurately and efficiently model 6 G channel for various scenarios? This paper tries to answer it. Firstly, the features of cluster-nuclei(CN) and principle of cluster-nuclei based channel model(CNCM) are introduced. Then, a novel modeling framework is proposed to implement CNCM,which consists four steps: propagation environment reconstruction, cluster-nuclei identification, multipath parameters generation, and channel coefficients generation. Three-dimensional environment with material information is utilized to map CN with scatterers in the propagation pathway. CN are identified by geometrical and electric field calculation based on environmental mapping, and multipath components within CN are calculated by statistical characteristics of angle, power and delay domains. Finally, we present a three-level verification structure to investigate the accuracy and complexity of channel modeling comprehensively. Simulation results reveal that CNCM can perform higher accuracy than geometrybased stochastic model while lower complexity compared with ray-tracing model for practical propagation environment.

关键词： channel model 6G cluster-nuclei environmental mapping scatterer ray-tracing geometrybased stochastic model

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A Note on Economic Equilibrium and Financial Networks

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Acta Mathematicae Applicatae Sinica 2014年第1期30卷 89-98页

作者： Li-ping zhang yuan ZHOU Department of Mathematical Sciences Tsinghua University

Nagurney （1999） used variational inequalities to study economic equilibrium and financial networks and applied the modified projection method to solve the problem. In this paper, we formulate the problem as a nonlinear complementarity problem. The complementarity model is just the KKT condition for the model of Nagurney （1999）. It is a simpler model than that of Nagurney （1999）. We also establish sufficient conditions for existence and uniqueness of the equilibrium pattern, which are weaker than those in Nagurney （]999）. Finally, we apply a smoothing Newton-type algorithm to solve the problem and report some numerical results.

关键词： economic equilibrium financial networks nonlinear complementarity problem smoothing Newton method

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A nano-structured TiO_(2)/CuO/Cu_(2)O coating on Ti-Cu alloy with dual function of antibacterial ability and osteogenic activity

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Journal of Materials Science & Technology 2022年第2期97卷 201-212页

作者： yuan zhang Shan Fu Lei Yang Gaowu Qin Erlin zhang Key Laboratory for Anisotropy and Texture of Materials(MoE) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Research Center for Metallic Wires Northeastern UniversityShenyang 110819China

Bacteria-associated infection and poor osseointegration are two main reasons for orthopedic implant ***-Cu alloy exhibited excellent antibacterial property,but still presented unsatisfied osteogenic ***,Ti-Cu alloy was surface modified by an alkali-heat treatment in this paper to improve the osteogenic ability without reduction in antibacterial ability.A TiO_(2)/CuO/Cu_(2)O composite coating with nanostructure was deposited on Ti-Cu *** coating showed increased roughness and great *** tests indicated that the modified Ti-Cu alloy exhibited stronger antibacterial ability against Staphylococcus aureus(***)than Ti-Cu ***,cell experiments demonstrated that the composite coating promoted initial adhesion and spreading of MC3T3-E1 cells,enhanced alkaline phosphatase(ALP)activities as well as extracellular matrix(ECM)mineralization,and significantly upregulated osteogenesis-related gene *** was suggested that the nano-structured TiO_(2)/CuO/Cu_(2)O coating on Ti-Cu alloy might provide a potential strategy for orthopedic implant failure.

关键词： Ti-Cu alloy Alkali-heat treatment Antibacterial property Osteogenic activity

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Federated Learning on Multimodal Data:A Comprehensive Survey

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Machine Intelligence Research 2023年第4期20卷 539-553页

作者： Yi-Ming Lin yuan Gao Mao-Guo Gong Si-Jia zhang yuan-Qiao zhang Zhi-yuan Li School of Electronic Engineering Xidian UniversityXi’an710071China

With the growing awareness of data privacy,federated learning(FL)has gained increasing attention in recent years as a major paradigm for training models with privacy protection in mind,which allows building models in a collaborative but private way without exchanging ***,most FL clients are currently *** the rise of edge computing,various types of sensors and wearable devices generate a large amount of data from different modalities,which has inspired research efforts in multimodal federated learning(MMFL).In this survey,we explore the area of MMFL to address the fundamental challenges of FL on multimodal ***,we analyse the key motivations for ***,the currently proposed MMFL methods are technically classified according to the modality distributions and modality annotations in ***,we discuss the datasets and application scenarios of ***,we highlight the limitations and challenges of MMFL and provide insights and methods for future research.

关键词： Federated learning multimodal learning heterogeneous data edge computing collaborative learning

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Detections of Gamma-Rays from Globular Clusters ESO 452-SC11, NGC 6380, Palomar 6 and UKS 1 with Fermi-LAT

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Research in Astronomy and Astrophysics 2022年第5期22卷 176-181页

作者： Min yuan Jiao Zheng Pengfei zhang Li zhang Department of Astronomy School of Physics and AstronomyKey Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China

The events from 157 globular clusters(GCs)are analyzed by using 12 yr long-term Pass 8 data from Fermi Large Area *** the 34 GCs reported in previous literatures,four additional GCs(ESO 452-SC11,NGC6380,Palomar 6 and UKS 1)in the Milky Way are detected as gamma-ray GC *** for UKS 1,these are known as the faintest GCs in long-wavelength *** data analysis has been performed for the four *** no pulsars are determined in radio and/or X-ray wavelengths so far,their gamma-ray pulsation emissions are not found,and no significant gamma-ray flux variability is *** numbers of MSPs within the four GCs are estimated based on the assumption that the MSPs within each GC emit similar amounts of *** gamma-ray results reported here could help us better understand the nature of gamma-ray emission origins for GCs.

关键词： (Galaxy:)globular clusters individual(ESO452-SC11,NGC6380,Palomar6andUKS1)

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Resource Allocation for Cognitive Network Slicing in PD-SCMA System Based on Two-Way Deep Reinforcement Learning

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China Communications 2024年第6期21卷 53-68页

作者： zhang Zhenyu zhang Yong yuan Siyu Cheng Zhenjie School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Beijing Key Laboratory of Work Safety Intelligent Monitoring(Beijing University of Posts and Telecommunications) Beijing 100876China

In this paper,we propose the Two-way Deep Reinforcement Learning(DRL)-Based resource allocation algorithm,which solves the problem of resource allocation in the cognitive downlink network based on the underlay *** users(SUs)in the cognitive network are multiplexed by a new Power Domain Sparse Code Multiple Access(PD-SCMA)scheme,and the physical resources of the cognitive base station are virtualized into two types of slices:enhanced mobile broadband(eMBB)slice and ultrareliable low latency communication(URLLC)*** design the Double Deep Q Network(DDQN)network output the optimal codebook assignment scheme and simultaneously use the Deep Deterministic Policy Gradient(DDPG)network output the optimal power allocation *** objective is to jointly optimize the spectral efficiency of the system and the Quality of Service(QoS)of *** results show that the proposed algorithm outperforms the CNDDQN algorithm and modified JEERA algorithm in terms of spectral efficiency and QoS ***,compared with the Power Domain Non-orthogonal Multiple Access(PD-NOMA)slices and the Sparse Code Multiple Access(SCMA)slices,the PD-SCMA slices can dramatically enhance spectral efficiency and increase the number of accessible users.

关键词： cognitive radio deep reinforcement learning network slicing power-domain non-orthogonal multiple access resource allocation

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Largest H-eigenvalue of uniform s-hypertrees

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Frontiers of Mathematics in China 2018年第2期13卷 301-312页

作者： yuan HOU An CHANG Lei zhang Center for Discrete Mathematics and Theoretical Computer Science Fuzhou University Puzhou 350000 China Department of Computer Engineering Fuzhou University Zhicheng College Fuzhou 350000 China

The k-uniform s-hypertree G = （V, E） is an s-hypergraph, where 1 ≤ s ≤ k - 1, and there exists a host tree T with vertex set V such that each edge of G induces a connected subtree of T. In this paper, some properties of uniform s-hypertrees are establised, as well as the upper and lower bounds on the largest H-eigenvalue of the adjacency tensor of k-uniform s-hypertrees in terms of the maximal degree A. Moreover, we also show that the gap between the maximum and the minimum values of the largest H-eigenvalue of k-uniform s-hypertrees is just （△S/k）.

关键词： Largest H-eigenvalue spectral radius adjacency tensor hypertree

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Synthesis and Characterization of Ion-exchange Sulfonated Poly (ether sulfone)

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Chinese Chemical Letters 2006年第4期17卷 447-448页

作者： Fan Xiu MENG Chun Qing zhang Lian LIU yuan yuan zhang Department of Polymer Materials Science School of Chemical Engineer Dalian University of Technology Dalian 116012

N,N＇-Bis（3-hydroxyphenyl）-1,8,4,5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1,8,4,5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization of this bisimide with 4,4＇-difluorodiphenylsulfone and disodium 3,3＇-disulfonate4,4＇-difluorodiphenylsulfone gave ion-exchange sulfonated poly（ether sulfone）. The structure of the title compound was characterized with H-NMR and its polymer was characterized with FT-IR.

关键词： Bisimide ion-exchange polymer sulfonated poly(ether sulfone).

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