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Spatial distribution of supra-permafrost groundwater in the Qinghai-Tibet Engineering Corridor using inversion models

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Advances in Climate Change Research 2024年第1期15卷 31-41页

作者： yu GAO Ming-Tang CHAI Wei ma yu-Tao GAO State Key Laboratory of Frozen Soils Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 73000China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China School of Civil and Hydraulic Engineering Ningxia UniversityYinchuan 750021China

Supra-permafrost groundwater(SPG)is a key factor that causes damage to highways and railways in the Qinghai-Tibet Engineering Corridor(QTEC).It is difficult to monitor SPG in the field due to their complex formation mechanisms and movement *** single-site field monitoring studies limit the spatial and temporal precision of SPG spatial *** determine the moisture content of shallow soils and the SPG distribution along the QTEC,this work employed the temperature vegetation dryness index and remote sensing models for groundwater table distribution *** accuracies of the models were validated using mea-surements obtained from different sites in the *** the permafrost zones of the QTEC,72%,22%and 6%of the SPG were located at depths of 0.5-1,1 m,***,79.4%of the area along the Qinghai-Tibet Highway(QTH)(Xidatan-Tanggula)section contained *** these sections with SPG,37.9%have an SPG table at depths of 0.5-0.8 *** study preliminarily explored the SPG distribution in the QTEC with a 30 m *** findings can help improve the spatial scale of SPG research,provide a basis for the analysis of the hydrothermal mechanisms,and serve as a guide in the assessment of operational risks and road structure designs.

关键词： Dryness index Landsat Soil moisture Groundwater level Qinghai-Tibet Engineering Corridor

Effect of annealing on the electrical performance of N-polarity GaN Schottky barrier diodes

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Journal of Semiconductors 2024年第4期45卷 48-55页

作者： Nuo Xu Gaoqiang Deng Haotian ma Shixu yang yunfei Niu Jiaqi yu yusen Wang Jingkai Zhao yuantao Zhang State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

A nitrogen-polarity(N-polarity)GaN-based high electron mobility transistor(HEMT)shows great potential for high-fre-quency solid-state power amplifier applications because its two-dimensional electron gas(2DEG)density and mobility are mini-mally affected by device ***,the Schottky barrier height(SBH)of N-polarity GaN is *** leads to a large gate leakage in N-polarity GaN-based *** this work,we investigate the effect of annealing on the electrical characteristics of N-polarity GaN-based Schottky barrier diodes(SBDs)with Ni/Au *** results show that the annealing time and tem-perature have a large influence on the electrical properties of N-polarity GaN *** to the N-polarity SBD without annealing,the SBH and rectification ratio at±5 V of the SBD are increased from 0.51 eV and 30 to 0.77 eV and 7700,respec-tively,and the ideal factor of the SBD is decreased from 1.66 to 1.54 after an optimized annealing *** analysis results suggest that the improvement of the electrical properties of SBDs after annealing is mainly due to the reduction of the inter-face state density between Schottky contact metals and N-polarity GaN and the increase of barrier height for the electron emis-sion from the trap state at low reverse bias.

关键词： nitrogen polarity GaN Schottky barrier diodes annealing interface state

Distributed active vibration control for helicopter based on diffusion collaboration

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Chinese Journal of Aeronautics 2024年第8期37卷 208-232页

作者： yang yuAN yang LU Xunjun ma Jingliang LI Huiyu yuE National Key Laboratory of Helicopter Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China Wuhan Second Ship Design and Research Institute Wuhan 430205China

The active vibration control technology has been successfully applied to several helicopter ***,with the increasing of control scale,traditional centralized control algorithms are experiencing significant increase of computational complexity and physical implementation *** address this issue,a diffusion collaboration-based distributed Filtered-x Least Mean Square algorithm applied to active vibration control is proposed,drawing inspiration from the concept of data fusion in wireless sensor *** algorithm distributes the computation load to each node,and constructs the active vibration control network topology of large-scale system by discarding the weak coupling secondary paths between nodes,achieving distributed active vibration *** order to thoroughly validate the effectiveness and superiority of this algorithm,a helicopter fuselage model is designed as the research ***,the excellent vibration reduction performance of the proposed algorithm is confirmed through ***,specialized node control units are developed,which utilize STM32 microcontroller as the processing ***,a distributed control system is constructed based on multi-processor *** on this foundation,a large-scale active vibration control experimental platform is *** on the platform,experiments are carried out,involving the 4-input 4-output system and the 8-input 8-output *** experimental results demonstrate that under steady-state harmonic excitation,the proposed algorithm not only ensures control effectiveness but also reduces computational complexity by 50%,exhibiting faster convergence speed compared with traditional centralized *** time-varying external excitation,the proposed algorithm demonstrates rapid tracking of vibration changes,with vibration amplitudes at all controlled points declining by over 94%,proving the strong robustness and adaptive capability of the algorithm

关键词： Helicopter Active vibration control Diffusion collaboration Distributed control Experiment

Electrocatalytic coupling of anodic nitrogen oxidation and cathodic nitrate reduction for ammonia synthesis from air and water

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Nano Research 2024年第9期17卷 7824-7829页

作者： Aijing ma Jianzhou Gui Yanmei Huang Yifu yu State Key Laboratory of Separation Membranes and Membrane Processes Tianjin Key Laboratory of Green Chemical Technology and Process EngineeringSchool of Chemical Engineering and TechnologyTiangong UniversityTianjin 300387China Institute of Molecular Plus School of Chemical EngineeringTianjin UniversityTianjin 300072China

Ammonia plays a vital role in present agriculture and industry,and is also regarded as a next-generation clean energy *** development of electrocatalysis raises an opportunity to make ammonia synthesis compatible with intermittent and variable renewable energy sources such as solar and wind ***,the direct ammonia electrosynthesis from N_(2)reduction is still challenging due to the much easier hydrogen evolution competition *** this perspective,we propose a novel strategy for ammonia electrosynthesis from air and water based on the coupling of anodic nitrogen oxidation and cathodic nitrate *** methods for breaking the bottlenecks of anodic nitrogen oxidation and cathodic nitrate reduction are discussed *** that,key issues that need to be considered in the coupled system are proposed for the application of this strategy.

关键词： electrocatalysis nitrogen oxidation nitrate reduction nitrogen fixation ammonia synthesis

Unraveling high efficiency multi-step sodium storage and bidirectional redox kinetics synergy mechanism of cobalt-doping vanadium disulfide anode

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Journal of Energy Chemistry 2024年第7期94卷 148-157页

作者： Enzhi Li Mingshan Wang yuanlong Feng Lin yang Qian Li Zhenliang yang Junchen Chen Bo yu Bingshu Guo Zhiyuan ma yun Huang Jiangtao Liu Xing Li School of New Energy and materials Southwest Petroleum UniversityChengdu 610500SichuanChina Institute of materials China Academy of Engineering PhysicsMianyang 621908SichuanChina State Key Laboratory of Advanced Chemical Power Sources Guizhou Meiling Power Sources Co.Ltd.Zunyi 563003GuizhouChina school of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001HeilongjiangChina

Sodium-based storage devices based on conversion-type metal sulfide anodes have attracted great atten-tion due to their multivalent ion redox reaction ***,they also suffer from sodium polysul-fides(NaPSs)shuttling problems during the sluggish Na^(+) redox process,leading to"voltage failure"and rapid capacity ***,a metal cobalt-doping vanadium disulfide(Co-VS_(2))is proposed to simulta-neously accelerate the electrochemical reaction of VS_(2) and enhance the bidirectional redox of soluble *** is found that the strong adsorption of NaPSs by V-Co alloy nanoparticles formed in situ during the conversion reaction of Co-VS_(2) can effectively inhibit the dissolution and shuttle of NaPSs,and ther-modynamically reduce the formation energy barrier of the reaction path to effectively drive the complete conversion reaction,while the metal transition of Co elements enhances reconversion kinetics to achieve high ***,Co-VS_(2) also produce abundant sulfur vacancies and unsaturated sulfur edge defects,significantly improve ionic/electron diffusion ***,the Co-VS_(2) anode exhibits ultrahigh rate capability(562 ma h g^(-1) at 5 A g^(-1)),high initial coulombic efficiency(~90%)and 12,000 ultralong cycle life with capacity retention of 90%in sodium-ion batteries(SIBs),as well as impressive energy/power density(118 Wh kg^(-1)/31,250 W kg^(-1))and over 10.000 stable cycles in sodium-ion hybrid capacitors(SIHCs).Moreover,the pouch cell-type SIHC displays a high-energy density of 102 Wh kg^(-1) and exceed 600 stable *** work deepens the understanding of the electrochemical reaction mechanism of conversion-type metal sulfide anodes and provides a valuable solution to the shuttlingofNaPSs inSIBsandSIHCs.

关键词： Sodium-ionbatteries Sodium-ion hybrid capacitors Pouch cells Vanadium disulfide Shuttle effect

Light-controlled switchable underwater adhesive

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Smartmat 2024年第2期5卷 115-123页

作者： Song yang Yanfei ma Chenxi Qin Zhizhi Zhang Jianqing yu Xiaowei Pei Bo yu Wenbo Sheng Feng Zhou Weimin Liu Northwestern Polytechnical University Center of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringXi'anChina State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouChina Shandong Laboratory of Yantai Advanced materials and Green manufacture Yantai Zhongke Research Institute of Advanced Materials and Green Chemical EngineeringYantaiChina

Despite extensive efforts in designing and preparing switchable underwater adhesives,it is not easy to regulate the underwater adhesion strength locally and ***,we design and synthesize photoreversible copolymer of poly[dopamine methacrylamide-co-methoxyethyl-acrylate-co-7-(2-methacryloyloxyethoxy)-4-methylcoumarin].Due to the dynamic formation and breaking of chemical crosslinking networks within the smart adhesives,the material shows widely tunable adhesion strength from∼150 to∼450 kPa and long-range reversible maneuverability under orthogonal 254 and 365 nm ultraviolet light stimulation via the coumarin dimerization and ***,the adhesive exhibits good circulation performance and stability in an acid–base *** also demonstrated that the bolt can be coated with the smart adhesive material for on-demand *** design principle opens the door to the development of remotely controllable high-performance smart underwater adhesives.

关键词： dynamic covalent bonds photoresponsive reversible adhesion switchable adhesion underwater adhesion

Electronic structure regulation and built-in electric field synergistically strengthen photocatalytic nitrogen fixation performance on Ti-BiOBr/TiO_(2)heterostructure

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Rare Metals 2024年第3期43卷 1125-1138页

作者： Ru-Qi Li yu-Jie Bian Chun-Ming yang Li Guo Tao-Xia ma Chuan-Tao Wang Feng Fu Dan-Jun Wang College of Chemistry and Chemical Engineering Yan’an UniversityYan’an Key Laboratory of Green Catalysis and Quality Improvement and Utilization of Low Rank CoalYan’an716000China

At present,industrial synthetic ammonia was still obtained through the Hubble-Bosch process,with large energy *** is a research hotspot to realize green synthetic ammonia by using solar *** difficulty of photocatalytic ammonia synthesis was that the photo-excited electrons have not enough energy to active N≡*** this study,Ti was doped into BiOBr by one-step hydrothermal method,which was oxidized into TiO_(2)when the doping amount reaches the maximum,in situ forming Ti_(0.31)B_(0.69)OB/TiO_(2)*** from the synergistic effect of Ti doping and S-scheme heterojunction,the synthetic ammonia efficiency of Ti_(0.31)B_(0.69)OB/TiO_(2)-11.96 reached 1.643 mmol·g_(cat)^(-1)at mild conditions and without hole scavenger for up to 7 h,the efficiency of synthetic ammonia is 115 times,10.5 times and 3.3 times of that of BiOBr,Ti_(0.31)B_(0.69)OB and TiO_(2),***,DFT calculation confirms that Ti doping accurately refine the electronic structure of BiOBr,facilitate nitrogen adsorption activation and reduce hydrogenation reaction energy barrier,thus accelerating the reaction kinetics of photocatalytic nitrogen reduction(NRR),Meanwhile,constructing S-scheme heterojunction boosts the separation and transfer of photogenerated electron-hole pairs,improving the reduction ability of electrons in the conduction band of TiO_(2)and the oxidation ability of holes in the valence band of Ti_(0.31)B_(0.69)OB.

关键词： S-scheme heterostructure Electronic structure regulation Built-in electric field Synergistical stren4gthening Photocatalytic nitrogen fixation

Exploring the complex trade-offs and synergies of global ecosystem services

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Environmental Science and Ecotechnology 2024年第5期21卷 141-148页

作者： Jinnan Wang Wenjun Wu Meng yang yueming Gao Jiacheng Shao Weishan yang Guoxia ma Fang yu Nan Yao Hongqiang Jiang State Environmental Protection Key Laboratory of Environmental Planning and Policy Simulation Chinese Academy of Environmental PlanningBeijing100041China The Center for Eco-Environmental Accounting Chinese Academy of Environmental PlanningBeijing100041China The Innovation Center for Eco-environment-Oriented Development Chinese Academy of Environmental PlanningBeijing100041China School of Environment Beijing Normal UniversityBeijing100875China College of Environmental&Resource Sciences Zhejiang UniversityHangzhou310058China College of Economics&management Northwest A&F UniversityYangling712100China

The trade-off and synergy relationship of ecosystem services is an important topic in the current *** value of each service provided by the ecosystem is substantially affected by human activities,and conversely,its changes will also affect the relevant human *** to varying tradeoffs among ecosystem services and synergies between them that can either increase or decrease,it is difficult to optimize multiple ecosystem services simultaneously,making it a huge challenge for ecosystem *** study firstly develops a global Gross Ecosystem Product(GEP)accounting *** uses remote sensing data with a spatial resolution of 1 km to estimate the ecosystem services of forests,wetlands,grasslands,deserts,and farmlands in 179 major countries in *** results show that the range of global GEP values is USD 112e197 trillion,with an average value of USD 155 trillion(the constant price),and the ratio of GEP to gross domestic product(GDP)is *** tradeoffs and the synergies among different ecosystem services in each continent and income group have been further *** found a correspondence between the income levels and the synergy among ecosystem services within each *** specific ecosystem services,there are strong synergies between oxygen release,climate regulation,and carbon sequestration services.A trade-off relationship has been observed between flood regulation and other services,such as water conservation and soil retention services in low-income *** results will help clarify the roles and the feedback mechanisms between different stakeholders and provide a scientific basis for optimizing ecosystem management and implementing ecological compensation schemes to enhance human well-being.

关键词： Ecosystem services Biophysical quantity Monetary value Trade-off Synergy

A new method for evaluating wedges of steel plates and strips

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Journal of Iron and Steel Research International 2024年第7期31卷 1719-1735页

作者： Xiao-bao ma Xiao-xin ma Tao Wang Zhong-kai Ren yu-cheng Ren College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024ShanxiChina Ministry of Education Engineering Research Center of Advanced Metal Composite Forming Technology and Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina China National Heavy machinery Research Institute Co. Ltd.Xi'an 710018ShaanxiChina Faculty of Mechanical Engineering Hebei University of ArchitectureZhangjiakou 075000HebeiChina

To overcome the inaccuracy problem of the traditional wedge evaluation of steel plates and strips caused by the ran-domness of the thicknesses of two local points and improve the reliability of the wedge index,the double-centroid method for the wedge evaluation was proposed,and a model based on the centroid theory was ***,an integral model for the discrete thickness values of the cross-section profiles was *** discussion focused on the distinct characteristics of the two-point method,asymmetric method,and double-centroid method in evaluating the asymmetric distribution of *** three methods were employed to evaluate the wedge values of both the theoretical and measured cross-sections of steel plates and strips,and the accuracies of three wedge evaluation models were analyzed and *** results showed that the double-centroid method objectively reflects the degree and variation characteristics of the wedge values of the cross-sections of steel plates and strips,and this method is feasible,reliable,and outstanding.

关键词： Steel plate and strip Wedge Two-point method Double-centroid method Reliability