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Catalyst-free and Reprocessable Aromatic Polydithiourethanes

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Chinese Journal of Polymer Science 2024年第10期42卷 1435-1441,I0007页

作者： Bo Yang Hai-Jun Feng tian-tian Ni Xiao-Rui Zhou Tao Xie ning Zheng State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310058China Department of Colorectal Surgery and Oncology Key Laboratory of Cancer Prevention and InterventionMinistry of EducationThe Second Affiliated HospitalZhejiang University School of MedicineHangzhou310009China

The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks,thereby meeting the sustainable requirements for polymer ***,the mechanical properties of many materials often decline significantly upon reprocessing due to side reactions caused by harsh processing *** this work,we find that the aromatic dithiocarbamate bond can undergo dissociation under mild conditions without the need for a catalyst,enabling the efficient reprocessing of the corresponding *** a consequence,the mechanical properties of the polydithiourethane can be largely preserved after *** discovery of this dynamic chemistry is anticipated to broaden the potential for material design in dynamic covalent polymer networks.

关键词： Reprocessing Polydithiourethane Dynamic covalent bond

Fracture geometry and breakdown pressure of radial borehole fracturing in multiple layers

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Petroleum Science 2024年第1期21卷 430-444页

作者： Yu-ning Yong Zhao-Quan Guo Shou-Ceng tian Lu-Yao Ma tian-Yu Wang Mao Sheng National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China Beijing Petroleum Machinery Company Limited CNPC Engineering Technology R&D Company LimitedBeijing102206China Smart Energy Co. LtdChina Xiongan GroupXiong’an New Area071000HebeiChina

Radial borehole fracturing that combines radial boreholes with hydraulic fracturing is anticipated to improve the output of tight oil and gas *** paper aims to investigate fracture propagation and pressure characteristics of radial borehole fracturing in multiple layers.A series of laboratory experiments with artificial rock samples(395 mm×395 mm×395 mm)was conducted using a true triaxial fracturing *** crucial factors corresponding to the vertical distance of adjacent radial borehole layers(vertical distance),the azimuth and diameter of the radial borehole are *** results show that radial borehole fracturing in multiple layers generates diverse fracture *** types of fractures are identified based on the connectivity between hydraulic fractures and radial *** vertical distance significantly influences fracture propagation perpendicular to the radial borehole *** increase in the vertical distance impedes fracture connection across multiple radial borehole layers and reduces the fracture propagation distance along the radial borehole *** azimuth also influences fracture propagation along the radial borehole *** the azimuth reduces the guiding ability of radial boreholes,which makes the fracture quickly curve to the maximum horizontal stress *** breakdown pressure correlates with diverse fracture geometries *** the fractures connect multi-layer radial boreholes,increasing the vertical distance decreases the breakdown *** the azimuth and increasing the diameter also decrease the breakdown *** extrusion force exists between the adjacent fractures generated in radial boreholes in multiple rows,which plays a crucial role in enhancing the guiding ability of radial boreholes and results in higher breakdown *** research provides valuable theoretical insights for the field application of radial borehole fracturing technology in tight oil and g

关键词： Multi-layer radial boreholes Hydraulic fracturing Fracture propagation Pressure characteristic

Unveiling evapotranspiration patterns and energy balance in a subalpine forest of the Qinghai-Tibet Plateau:observations and analysis from an eddy covariance system

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Journal of Forestry Research 2024年第3期35卷 175-188页

作者： Niu Zhu Jinniu Wang Dongliang Luo Xufeng Wang Cheng Shen ning Wu ning Zhang Binghui tian Aihong Gai Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041People's Republic of China College of Resources and Environmental Sciences Gansu Agricultural UniversityLanzhou 730070People's Republic of China Mangkang Ecological Monitoring Station Tibet Ecological Security Barrier Ecological Monitoring NetworkQamdo 854500People's Republic of China Northwest Institute of Eco Environmental Resources Chinese Academy of SciencesLanzhou 730000People's Republic of China

Evapotranspiration is an important parameter used to characterize the water cycle of *** under-stand the properties of the evapotranspiration and energy balance of a subalpine forest in the southeastern Qinghai-Tibet Plateau,an open-path eddy covariance system was set up to monitor the forest from November 2020 to October 2021 in a core area of the Three Parallel Rivers in the Qing-hai-Tibet *** results show that the evapotranspira-tion peaked daily,the maximum occurring between 11:00 and 15:*** factors had significant effects on evapotranspiration,among them,net radiation the greatest(R^(2)=0.487),and relative humidity the least(R^(2)=0.001).The energy flux varied considerably in different seasons and sensible heat flux accounted for the main part of turbulent *** energy balance ratio in the dormant season was less than that in the growing season,and there is an energy imbalance at the site on an annual time scale.

关键词： Evapotranspiration Energy balance Subalpine forest Three Parallel Rivers region Southeast Qinghai-Tibet Plateau

Efficiency-oriented vehicle relocation of shared autonomous electric fleet in station-based car-sharing system

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第4期11卷 681-699页

作者： ning Wang Hangqi tian Jiahui Guo Huahua Wu Jian Lyu School of Automotive Studies Tongji UniversityShanghai 201804China State Grid Zhejiang Electric Power Co. Ltd.Hangzhou 310007China State Grid Zhejiang Electric Vehicle Service Co. Ltd.Hangzhou 310012China

Long waiting delays for users and significant imbalances in vehicle distribution are bothering traditional station-based one-way electric car-sharing system *** address the problems above,a“demand forecast-station status judgement-vehicle relocation”multistage dynamic relocation algorithm based on the automatic formation cruising technology was proposed in this *** stage one,a novel trip demand forecast model based on the long short-term memory network was established to predict users'car-pickup and car-return order volumes at each *** stage two,a dynamic threshold interval was determined by combining the forecast results with the actual vehicle distribution among stations to evaluate the status of each *** vehicle-surplus,vehicleinsufficient,vehicle-normal stations,and the number of surplus or insufficient vehicles for each station were *** stage three,setting driving mileage and carbon emission as the optimization objectives,an integer linear programming mathematical model was constructed and the optimal vehicle relocation scheme was obtained by the commercial solver *** 43 stations and 187 vehicles in Jiading District,Shanghai,China,as a case study,results showed that rapid vehicle rebalancing among stations with minimum carbon emissions could be realized within 15 min and the users’car-pickup and car-return demands could be fully satisfied without any refusal.

关键词： Sustainable transportation One-way car-sharing Shared autonomous electric fleet Multistage dynamic relocation algorithm

Design of low-frequency circular metastructure isolators with high-load-bearing capacity

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Chinese Journal of Aeronautics 2024年第10期37卷 207-220页

作者： ning CHEN Zhichun YANG Te YANG Yizhou SHEN Wei tian Yanlong XU School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China National Key Laboratory of Strength and Structural Integrity Xi’an 710065China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an 710049China

Traditional vibration isolation structures cannot work effectively for low-frequency vibration under heavy loads,due to the inherent contradiction between the high-static and lowdynamic stiffness of these *** the challenge can be effectively addressed by introducing a negative stiffness mechanism,the existing structures inevitably have complex ***,a class of man-made structures with both extraordinary mechanical properties and simple configurations,provide a new insight for low-frequency vibration isolation *** this paper,circular metastructure isolators consisting of some simple beams are designed for low-frequency vibration,including a single-layer isolator and a double-layer isolator,and their static and dynamic characteristics are studied,*** the static characteristic,the force–displacement and stiffness–displacement curves are obtained by finite element simulation;for the dynamic characteristic,the vibration transmissibility curves are obtained analytically and *** result shows that the circular nonlinear single-layer isolator has excellent lowfrequency isolation performance,and the isolation frequency band will decrease about 20 Hz when the isolated mass is fixed at 1.535 kg,compared with a similar circular linear *** static and dynamic properties are well verified through *** work provides an innovative approach for the low-frequency vibration isolation and has wide potential applications in aeronautics.

关键词： Isolator Low-frequency Curved beam Metastructure Stiffness

A Review of Intelligent Configuration and Its Security for Complex Networks

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Chinese Journal of Electronics 2024年第4期33卷 920-947页

作者： Yue ZHAO Bin YANG Fei TENG Xianhua NIU ning HU Bo tian Science and Technology on Communication Security Laboratory School of Computer and Information Engineering Chuzhou University School of Computing and Artificial Intelligence Southwest Jiaotong University School of Computer and Software Engineering Xihua University Cyberspace Institute of Advanced Technology Guangzhou University

Complex networks are becoming more complex because of the use of many components with diverse technologies. In fact, manual configuration that makes each component interoperable has breed latent danger to system security. There is still no comprehensive review of these studies and prospects for further research. According to the complexity of component configuration and difficulty of security assurance in typical complex networks, this paper systematically reviews the abstract models and formal analysis methods required for intelligent configuration of complex networks, specifically analyzes, and compares the current key technologies such as configuration semantic awareness, automatic generation of security configuration, dynamic deployment, and verification evaluation. These technologies can effectively improve the security of complex networks intelligent configuration and reduce the complexity of operation and maintenance. This paper also summarizes the mainstream construction methods of complex networks configuration and its security test environment and detection index system, which lays a theoretical foundation for the formation of the comprehensive effectiveness verification capability of configuration security. The whole lifecycle management system of configuration security process proposed in this paper provides an important technical reference for reducing the complexity of network operation and maintenance and improving network security.

关键词： Complex networks Intelligent configuration Configuration security Software defined network Lifecycle management SOFTWARE ALGORITHM AGENT

A Review on the Security of the Ethereum-Based DeFi Ecosystem

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 69-101页

作者： Yue Xue Dunqiu Fan Shen Su Jialu Fu ning Hu Wenmao Liu Zhihong tian Cyberspace Institute of Advanced Technology Guangzhou UniversityGuanzhou510000China Innovation Center NSFOCUS Inc.Beijing100089China Engineering Research Center of Integration and Application of Digital Learning Technology Ministry of EducationBeijing100816China

Decentralized finance(DeFi)is a general term for a series of financial products and *** is based on blockchain technology and has attracted people’s attention because of its open,transparent,and intermediary *** them,the DeFi ecosystem based on Ethereum-based blockchains attracts the most ***,the current decentralized financial system built on the Ethereum architecture has been exposed to many smart contract vulnerabilities during the last few ***,we believe it is time to improve the understanding of the prevailing Ethereum-based DeFi ecosystem security *** that end,we investigate the Ethereum-based DeFi security issues:1)inherited from the real-world financial system,which can be solved by macro-control;2)induced by the problems of blockchain architecture,which require a better blockchain platform;3)caused by DeFi invented applications,which should be focused on during the project *** on that,we further discuss the current solutions and potential directions ofDeFi *** to our research,we could provide a comprehensive vision to the research community for the improvement of Ethereum-basedDeFi ecosystem security.

关键词： Blockchain smart contract decentralized finance DeFi security

Boosting the catalytic performance of Cu-SAPO-34in NO_(x) removal via hydrothermal treatment

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Journal of Environmental Sciences 2024年第1期135卷 640-655页

作者： Xiaoyan tian Huimin Wang Siyuan Xu Lianyun Gao Jinyan Cao Jianjun Chen Qiulin Zhang Ping ning Jiming Hao Faculty of Environmental Science and Engineering Kunming University of Science and TechnologyKunming 650500China National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries Kunming University of Science and TechnologyKunming 650500China School of Environment State Key Joint Laboratory of Environment Simulation and Pollution ControlTsinghua UniversityBeijing 100084China

Phosphate ions promoted Cu-SAPO-34(P-Cu-SAPO-34)were prepared using bulk CuO particles as Cu^(2+)precursor by a solid-state ion exchange technique for the selective catalytic reduction of NO_(x) with NH_3(NH_3-SCR).The effects of high temperature(H-T)hydrothermal aging on the NO_(x) removal(de-NO_(x))performance of Cu-SAPO-34 with and without phosphate ions were systematically investigated at atomic *** results displayed that both Cu-SAPO-34 and P-Cu-SAPO-34 presented relatively poor NO_(x) removal activity with a low conversion(<30%)at 250-500℃.However,after H-T hydrothermal treatment(800℃ for 10 hr at 10%H_2O),these two samples showed significantly satisfied NO_(x) elimination performance with a quite high conversion(70%-90%)at 250-500℃.Additionally,phosphate ions decoration can further enhance the catalytic performance of Cu-SAPO-34 after hydrothermal treatment(Cu-SAPO-34H).The textural properties,morphologies,structural feature,acidity,redox characteristic,and surface-active species of the fresh and hydrothermally aged samples were analyzed using various characterization *** systematical characterization results revealed that increases of 28%of the isolated Cu^(2+)active species(Cu^(2+)-2Z,Cu(OH)^(+)-Z)mainly from bulk CuO and 50%of the Bronsted acid sites,the high dispersion of isolated Cu^(2+)active component as well as the Bronsted acid sites were mainly responsible for the accepted catalytic activity of these two hydrothermally aged samples,especially for P-Cu-SAPO-34H.

关键词： NH_(3)-SCR Cu-SAPO-34 Hydrothermal induced Phosphate ions

Multi-omics analysis of human tendon adhesion reveals that ACKR1-regulated macrophage migration is involved in regeneration

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Bone Research 2024年第2期12卷 390-406页

作者： Xinshu Zhang Yao Xiao Bo Hu Yanhao Li Shaoyang Zhang Jian tian Shuo Wang Zaijin Tao Xinqi Zeng ning-ning Liu Baojie Li Shen Liu Department of Orthopaedics Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine600 Yishan RdShanghai 200233PR China Section of Spine Surgery Department of OrthopaedicsChangzheng HospitalNaval Medical UniversityShanghai 200003PR China Bio-X Institutes Key Laboratory for the Genetics of Developmental and Neuropsychiatric DisordersMinistry of EducationShanghai Jiao Tong UniversityShanghai 200241PR China Department of Orthopaedics Wuxi Ninth People’s Hospital Affiliated to Soochow UniversityWuxi 214062PR China State Key Laboratory of Systems Medicine for Cancer Center for Single-Cell OmicsSchool of Public HealthShanghai Jiao Tong University School of MedicineShanghai 200025China

Tendon adhesion is a common complication after tendon injury with the development of accumulated fibrotic tissues without effective anti-fibrotic therapies,resulting in severe *** are widely recognized as a fibrotic trigger during peritendinous adhesion ***,different clusters of macrophages have various functions and receive multiple regulation,which are both still *** our current study,multi-omics analysis including single-cell RNA sequencing and proteomics was performed on both human and mouse tendon adhesion tissue at different stages after tendon *** transcriptomes of over 74000 human single cells were *** results,we found that SPP1^(+)macrophages,RGCC^(+)endothelial cells,ACKR1^(+)endothelial cells and ADAM12^(+)fibroblasts participated in tendon adhesion ***,despite specific fibrotic clusters in tendon adhesion,FOLR2^(+)macrophages were identified as an antifibrotic cluster by in vitro experiments using human ***,ACKR1 was verified to regulate FOLR2^(+)macrophages migration at the injured peritendinous site by transplantation of bone marrow from Lysm-Cre;R26R^(tdTomato) mice to lethally irradiated Ackr1^(-/-)mice(Ackr1^(-/-)chimeras;deficient in ACKR1)and control mice(WT chimeras).Compared with WT chimeras,the decline of FOLR2^(+)macrophages was also observed,indicating that ACKR1 was specifically involved in FOLR2^(+)macrophages *** together,our study not only characterized the fibrosis microenvironment landscape of tendon adhesion by multi-omics analysis,but also uncovered a novel antifibrotic cluster of macrophages and their *** results provide potential therapeutic targets against human tendon adhesion.

关键词： tendon analysis landscape