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Climatic implications in earlywood and latewood width indices of Chinese pine in north central China

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Journal of Forestry Research 2024年第3期35卷 143-153页

作者： Kaixuan yang Junzhou zhang Haowen Fan yuan Yan College of Geographic Sciences Qinghai Normal UniversityXining 810016People's Republic of China Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation(Ministry of Education) Xining 810016People's Republic of China Key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730030People's Republic of China Gansu Liancheng Forest Ecosystem Field Observation and Research Station Lanzhou UniversityLanzhou 730333People's Republic of China School of Geography and Information Engineering University of GeoscienceWuhan 430074People's Republic of China

Latewood width(LWW)indices of trees are considered a reliable proxy of summer precipitation in the Northern ***,the strong coupling and high correlation between earlywood width(EWW)and LWW indices often prevent registration of climate signals of the LWW *** this study,328-year-long earlywood width and latewood width chronologies were developed from Chinese pine at two sites in the Hasi Mountains,north central *** climate responses of these chronologies were analyzed and the LWW index used to derive sum-mer precipitation *** analyses showed that LWW was particularly influenced by earlywood growth and recorded stronger climate signals of the previous year as EWW,rather than those of the current year with infrequent summer climate ***,after removing the effect of earlywood growth using a simple regression model,the adjusted LWW chronology(LWW_(adj))showed a strong relationship with July precipitation in dry *** suggests that the LWW_(adj) chronology has the potential to be used to investigate long-term variability in summer precipitation in drought-limited regions.

关键词： Dendroclimatology Latewood width Climate response Summer precipitation Earlywood effect

Effect of Microstructure on Corrosion Fatigue Behavior of 1500 MPa Level Carbide-Free Bainite/Martensite Dual-Phase High Strength Steel

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Journal of Iron and Steel Research International 2011年第4期18卷 63-67页

作者： XU Lei WEI Dong-yuan YU yang zhang Han BAI Bing-zhe Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Influence of microstructure of the experimental steels on the corrosion fatigue behavior in 3.5% of NaCl aqueous solution was *** results show that compared with the full martensite（FM）steel,the carbide-free bainite/martensite（CFB/M）steel has higher corrosion fatigue strength and corrosion fatigue crack threshold（ΔKthcf）,and lower corrosion crack propagation rate [（da/dN）cf].

关键词： high strength steel carbide-free bainite/martensite dual-phase steel corrosion fatigue

Resilience-oriented Transmission Expansion Planning with Optimal Transmission Switching Under Typhoon Weather

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 129-138页

作者： yang yuan Heng zhang Haozhong Cheng Zheng Wang Key Laboratory of Control of Power Transmission and Conversion Ministry of EducationElectrical Engineering DepartmentShanghai Jiao Tong UniversityShanghaiChina State Grid East China Branch ShanghaiChina

This paper presents resilience-oriented transmission expansion planning(RTEP)with optimal transmission switching(OTS)model under typhoon *** proposed model carefully considers the uncertainty of component vulnerability by constructing a typhoon-related box uncertainty set where component failure rate varies within a range closely related with typhoon ***,a min-max-min model is developed to enhance transmission network resilience,where the upper level minimizes transmission lines investment,the middle level searches for the probability distribution of failure status leading to max worst-case expected load-shedding(WCEL)under typhoon,and the lower level optimizes WCEL by economic dispatch(ED)and OTS.A nested decomposition algorithm based on benders decomposition is developed to solve the *** studies of modified IEEE 30-bus and 261-bus system of a Chinese region illustrate that:a)the proposed RTEP method can enhance resilience of transmission network with less investment than widely used RTEP method based on attacker and defender(DAD)model,b)the influence of OTS on RTEP is closely related with contingency severity and system scale and c)the RTEP model can be efficiently solved even in a large-scale system.

关键词： Decomposition algorithm optimal transmission switching resilience transmission expansion planning uncertainty vulnerability

Numerical Simulation Study on Influence of Equation of State on Internal Flow Field and Performance of S-CO_(2)Compressor

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Journal of Thermal Science 2024年第3期33卷 888-898页

作者： zhang Lei yang Zhenyu SUN Enhui zhang Qian AN Guangyao yuan Wei Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology North China Electric Power UniversityBaoding071003China School of Energy Power&Mechanical EngineeringNorth China Electric Power UniversityBaoding071028China

The low power consumption of the near-critical compressor is the key factor for the high efficiency of supercritical CO_(2)Brayton *** the numerical simulation of the compressor,the rapid changes in the thermophysical properties of the CO_(2)near the critical point make it difficult to capture the condensation *** paper investigates the influence of fluid physical properties on the condensation ***,the differences in the physical properties of CO_(2)in the SRK EOS(equation of state),PR EOS,and SW EOS are ***,the simulation of nozzles and compressors were carried out and *** show that the condensation positions predicted by the three EOSs are basically the *** with SW EOS,the disparities between the maximum condensation mass fraction predicted by the PR and SRK EOSs is5.7%and 11.5%,and that of total pressure ratio is 0.3%and 3.8%,*** results show that PR EOS can be considered for numerical simulation in engineering *** its physical property calculation results are closer to the actual physical properties while the physical properties change more gently,it has considerable accuracy and numerical stability.

关键词： supercritical carbon dioxide equation of state centrifugal compressor numerical simulation condensation

Enhancing strength of an ultra-low-carbon weathering steel to 700 MPa by adjusting Ti content

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Journal of Iron and Steel Research International 2023年第12期30卷 2494-2504页

作者： Tian-en Peng Zhi-wei Lian yuan-yang zhang Bo He Xue-wen Hu Tao Zhu Bo Jiang School of Materials Science and Engineering University of Science and Technology BeijingBeijing100083China Technical Center Ma’anshan Iron&Steel Co.Ltd.Ma’anshan243041AnhuiChina

The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti *** yield strength and elongation of the steel were 640 MPa and 25.5%,*** microstructure was ferrite and pearlite,and the average grain size was 5.4μ*** precipitates were mainly TiC with the size below 20 nm,and the average diameter was 18.2 *** yield strength of the newly proposed weathering steel with Ti content of 0.018%higher than that of the traditional steel reached up to 709 MPa,and the elongation was 23.5%.The ferrite grain was refined to 3.8μm,the fraction of TiC under 10 nm was obviously increased,and the average diameter of particles was 9.8 *** increase in Ti also promoted the recrystallization process,thus leading to the reduction in dislocation *** yield strength of the newly proposed weathering steel was increased to higher than 700 MPa by adjusting the Ti content mainly resulting from three aspects:grain refinement,precipitation and dislocation *** contributed values were 45,64 and–40 MPa,respectively.

关键词： Ti microalloying Weathering steel Microstructure Strength Plasticity

A stable one-point quadrature rule for three-dimensional numerical manifold method

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Science China(Technological Sciences) 2024年第5期67卷 1401-1416页

作者： zhang Ning ZHENG Hong yang Liang WU WenAn yuan Chi School of Civil Engineering Qinghai UniversityQinghai810016China Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing100124China Faculty of Engineering China University of GeoscienceWuhan430074China

We present a numerically stable one-point quadrature rule for the stiffness matrix and mass matrix of the three-dimensional numerical manifold method(3D NMM).The rule simplifies the integration over irregularly shaped manifold elements and overcomes locking issues,and it does not cause spurious modes in modal *** essential idea is to transfer the integral over a manifold element to a few moments to the element center,thereby deriving a one-point integration rule by the moments and making modifications to avoid locking *** the stiffness matrix,after the virtual work is decomposed into moments,higher-order moments are modified to overcome locking issues in nearly incompressible and bending-dominated *** the mass matrix,the consistent and lumped types are derived by *** particular,the lumped type has the clear advantage of *** proposed method is naturally suitable for 3D NMM meshes automatically generated from a regular *** tests justify the accuracy improvements and the stability of the proposed procedure.

关键词： three-dimensional numerical manifold method quadrature rule locking mass lumping

Hybrid concurrency control protocol for data sharing among heterogeneous blockchains

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Frontiers of Computer Science 2024年第3期18卷 1-12页

作者： Tiezheng GUO Zhiwei zhang Ye yuan Xiaochun yang Guoren WANG School of Computer Science and Technology Beijing Institute of TechnologyBeijing 100029China School of Computer Science and Engineering Northeastern UniversityShenyang 110167China

With the development of information technology and cloud computing,data sharing has become an important part of scientific *** traditional data sharing,data is stored on a third-party storage platform,which causes the owner to lose control of the *** a result,there are issues of intentional data leakage and tampering by third parties,and the private information contained in the data may lead to more significant ***,data is frequently maintained on multiple storage platforms,posing significant hurdles in terms of enlisting multiple parties to engage in data sharing while maintaining *** this work,we propose a new architecture for applying blockchains to data sharing and achieve efficient and reliable data sharing among heterogeneous *** design a new data sharing transaction mechanism based on the system architecture to protect the security of the raw data and the processing *** also design and implement a hybrid concurrency control protocol to overcome issues caused by the large differences in blockchain performance in our system and to improve the success rate of data sharing *** took Ethereum and Hyperledger Fabric as examples to conduct crossblockchain data sharing *** results show that our system achieves data sharing across heterogeneous blockchains with reasonable performance and has high scalability.

关键词： data sharing blockchain concurrency control protocol crosschain

BDSec:Security Authentication Protocol for BeiDou-Ⅱ Civil Navigation Message

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China Communications 2024年第6期21卷 206-218页

作者： Wu Zhijun zhang yuan yang Yiming Wang Peng Yue Meng School of Safety Science and Engineering Civil Aviation University of ChinaTianjin 300300China School of Electronic Information and Automation Civil Aviation University of ChinaTianjin 300300China

Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-Ⅱ civil navigation message(BDⅡ-CNAV) are vulnerable to spoofing attack and replay *** solve this problem,we present a security authentication protocol,called as BDSec,which is designed by using China’s cryptography Shangyong Mima(SM) series algorithms,such as SM2/4/9 and Zu Chongzhi(ZUC)*** BDSec protocol,both of BDⅡ-CNAV and signature information are encrypted using the SM4 algorithm(Symmetric encryption mechanism).The encrypted result is used as the subject authentication *** protocol applies SM9 algorithm(Identity-based cryptography mechanism) to protect the integrity of the BDⅡ-CNAV,adopts the SM2 algorithm(Public key cryptosystem) to guarantee the confidentiality of the important session information,and uses the ZUC algorithm(Encryption and integrity algorithm) to verify the integrity of the message authentication serial number and initial information and the information in authentication initialization sub-protocol *** results of the SVO logic reasoning and performance analysis show that BDSec protocol meets security requirements for the dual user identity authentication in BDS and can realize the security authentication of BDⅡ-CNAV.

关键词： BDII civil navigation messages(BDIICNAV) BeiDou navigation satellite system(BDS) identity-based cryptography mechanism navigation message authentication protocol(BDSec)

Facet-dependent activation of oxalic acid over hematite nanocrystals under the irradiation of visible light for efficient degradation of pollutants

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Journal of Environmental Sciences 2024年第8期142卷 204-214页

作者： Zhixiong yang yuan Li Xiaotian Wang Jiaming Li Jiquan Wang Gaoke zhang Hubei Key Laboratory of Mineral Resources Processing and Environment State Key Laboratory of Silicate Materials for ArchitecturesWuhan University of TechnologyWuhan 430070China Hubei Engineering Consulting Co. Ltd.Wuhan 430071China

Naturally occurring hematite has been widely studied in the Fenton-like system for water pollutant remediation due to its abundance and ***,its inadequate catalytic activity results in difficulty in effectively degrading pollutants in the catalytic degradation system that it ***,we constructed a photochemical system composed of hematite with{001}facet of high activity facet and low-cost and non-toxic oxalic acid(OA)for the removal of various types of *** removal rate for the degradation of metronidazole,tetracycline hydrochloride,Rhodamine B,and hexavalent chromium by hematite nanoplate with the exposed{001}facet activating OA under visible light irradiation was 4.75,2.25,2.33,and 2.74 times than that by the exposed{110}facet,*** functional theory(DFT)calculation proved that the OA molecule was more easily adsorbed on the{001}facet of hematite than that on the{110}facet,which would favor the formation of the more Fe(Ⅲ)-OA complex and reactive *** addition,the reactive site of metronidazole for the attraction of radicals was identified on the basis of the DFT calculation on the molecular occupied orbitals,and the possible degradation pathway for metronidazole included carbon chain fracture,hydroxyethyl-cleavage,denitrogenation,and ***,this finding may offer a valuable direction in designing an efficient iron-based catalyst based on facet engineering for the improved activity of Fenton-like systems such as OA activation.

关键词： Hematite Facet exposure Oxalic acid activation Fenton-like system Pollutant removal