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Microstructure,Corrosion and Mechanical Properties of Medium-Thick 6061-T6 Alloy/T2 Pure Cu Dissimilar Joints Produced by Double Side Friction Stir Z Shape Lap-Butt Welding

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 385-400页

作者： Jiuxing Tang Guoxin Dai Lei shi Chuansong wu Sergey Mironov Surendra Kumar Patel Song Gao Mingxiao wu MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing Shandong UniversityJinan 250061China Laboratory of Mechanical Properties of Nanoscale Materials and Superalloys Belgorod State UniversityBelgorod 308015Russia School of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China State Grid Henan Electric Power Research Institute Zhengzhou 450052China

A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar *** influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically *** indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding ***-FSZW joint was prone to form void defects in the bottom of the second-pass *** recrystallization mechanisms at the top and middle of the weld nugget zone(WNZ)were continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX).While the major recrystallization mechanism at the bottom of the WNZ was ***-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface,and the maximum tensile strength of this joint is 160.57 MPa,which is equivalent to 65.54%of pure Cu base ***,the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/*** demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance.

关键词： DS-FSZW Al/Cu dissimilar joint Corrosion behaviour Intermetallic compounds Microstructure Mechanical properties

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Sedimentary paleoenvironment and its control on organic matter enrichment in the Mesoproterozoic hydrocarbon source rocks in the Ordos Basin, southern margin of the North China Craton

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Petroleum Science 2024年第4期21卷 2257-2272页

作者： Zhi-Chen wu Ju-Ye shi Tai-Liang Fan Ming Jiang School of Energy Resources China University of Geosciences (Beijing) Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism Ministry of Education China University of Geosciences (Beijing)

The black shale of the Mesoproterozoic Cuizhuang Formation in the Changcheng System in Yongji city,North China Craton, is a potential source rock. Understanding the organic matter enrichment mechanism is crucial for evaluating source rock resources and understanding oil and gas accumulation *** this study, we evaluated the sedimentary paleoenvironment and organic matter enrichment mechanisms of shale using thin section observations, mineral composition analysis, organic geochemistry, and elemental geochemistry. We found significant differences in the sedimentary paleoenvironment and organic matter enrichment mechanisms between the lower Cuizhuang Formation and the Beidajian Formation shale. The Cuizhuang Formation was deposited in a late-stage, restricted basin environment during the rift phase, and elemental and geochemical indicators showed that the Cuizhuang Formation was in a suboxic-anoxic water environment, that was influenced by a warm and humid paleoclimate and submarine hydrothermal activities, which promoted the accumulation of organic matter. However, the enrichment of organic matter in the Cuizhuang Formation was mainly controlled by redox *** formation of suboxic-anoxic water environments may be closely related to the warm and humid paleoclimate and submarine hydrothermal activities. Warm conditions promote continental weathering and increase marine productivity, thereby consuming oxygen in the bottom water. Moreover, acidic hydrothermal activity also helps to establish an anoxic environment. Our results reveal the effects controlling various coupled mechanisms dominated by redox conditions, which may explain the development of source rocks in the Cuizhuang Formation.

关键词： Cuizhuang formation Paleoproterozoic source rocks Marine productivity Paleoenvironments Submarine hydrothermal activity Organic matter enrichment

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Counteracting effects on ENSO induced by ocean chlorophyll interannual variability and tropical instability wave-scale perturbations in the tropical Pacific

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Science China Earth Sciences 2024年第2期67卷 387-404页

作者： Rong-Hua ZHANG Feng TIAN Qidong shi Xiujun WANG Tongwen wu School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China Laoshan Laboratory Qingdao266237China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao266071China University of Chinese Academy of Sciences Beijing101408China Faculty of Geographical Sciences Beijing Normal UniversityBeijing100875China Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing100081China

Large perturbations in chlorophyll(Chl)are observed to coexist at interannual and tropical instability wave(TIW)scales in the tropical Pacific;at present,their combined effects on El Ni?o-Southern Oscillation(ENSO)through ocean biologyinduced heating(OBH)feedbacks are not understood ***,a hybrid coupled model(HCM)for the atmosphere and ocean physics-biogeochemistry(AOPB)in the tropical Pacific is adopted to quantify how ENSO can be modulated by Chl perturbations at interannual and TIW scales,individually or collectively,*** HCM-based sensitivity experiments demonstrate a counteracting effect on ENSO:the bio-climate feedback due to large-scale Chl interannual variability acts to damp ENSO through its impact on upper-ocean stratification and vertical mixing,whereas that due to TIW-scale Chl perturbations tends to amplify *** ENSO simulations are sensitively dependent on the ways Chl effects are represented at these different scales,it is necessary to adequately take into account these related differential Chl effects in climate modeling.A bias source for ENSO simulations is illustrated that is related with the Chl effects in the tropical Pacific,adding in a new insight into interactions between the climate system and ocean ecosystem on different scales in the *** results reveal a level of complexity of ENSO modulations resulting from Chl effects at interannual and TIW scales,which are associated with ocean biogeochemical processes and their interactions with physical processes in the tropical Pacific.

关键词： Ocean chlorophyll Bio-climate feedbacks Interannual variability Tropical instability waves Counteracting effects A hybrid coupled model

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Distribution, bioaccumulation, trophic transfer and risk assessment of trace elements in fish from a typical shallow outflow lake basin, China

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Frontiers of Environmental Science & Engineering 2024年第7期18卷 141-156页

作者： Miao He Guijian Liu Xiaodan shi Lei wu Qiang Chen CAS Key Laboratory of Crust-Mantle Materials and Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Anhui Academy of Environmental Sciences Hefei 230022China School of Resources and Environmental Engineering Hefei University of TechnologyHefei 230009China

Fish are important food sources for humans,and the availability of appropriate amount of trace elements(TEs)plays a crucial role in fish ***,due to large volumes of sewage discharge,high levels of certain elements are present in aquatic environments,and these elements accumulate in fish and potentially affect human *** this study,the distribution and bioaccumulation capacity of trace elements in six dominant fish species from Chaohu Lake(China)were *** results showed that the bioaccumulation capacity of fish for Zn was greater than other *** the source of the TEs in the fish were explored along with the concentration of the TEs in the aquatic environment,which indicated that TEs in fish were mainly obtained through ingestion and indirectly affected by the industrial activities in the ***,stable carbon and nitrogen isotopes were used to classify the trophic levels and explore the biological magnification of TEs of the *** was found that Sb and Sr showed biomagnification with the increase of trophic level of *** on the above analyses,the environmental biogeochemical cycle model of TEs in the lake was distinguished and established,which can offer valuable insights for sustainable fishery management in the downstream Yangtze River Delta ecosystem.

关键词： Trophic level Bioaccumulation Risk assessment Trace elements

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Theoretical design of polyazole based ligands for the separation of Am(Ⅲ)/Eu(Ⅲ)

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Chinese Chemical Letters 2024年第8期35卷 406-412页

作者： Lingling Su Qunyan wu Congzhi Wang Jianhui Lan Weiqun shi School of Nuclear Science and Technology University of South ChinaHengyang 421001China Laboratory of Nuclear Energy Chemistry Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

The extraction of radioactive minor actinides(An(Ⅲ))from lanthanides(Ln(Ⅲ))is an extremely impor-tant step in nuclear waste *** ligands with high-performance actinide-selectivity re-mains an essential *** works have reported that some polyazole based ligands exhibit good An(Ⅲ)/Ln(Ⅲ)separation ***,we first evaluated the effects of different polyazole side chains on the Am(Ⅲ)/Eu(Ⅲ)selectivity by exploring three pyridine-derived polyazole ligands L^(1),L^(2)and L^(3)with 1,2,4-triazole,1,2,3-triazole,and pyrazole side chains,respectively,using scalar relativistic theoretical *** coordination structures,bonding properties and thermodynamic behaviors of AmL(NO_(3))_(3)and EuL(NO_(3))_(3)complexes were investigated,which clarifies that the side chains do affect the electronic structure of ligand and its selectivity for Am(Ⅲ)/Eu(Ⅲ)***,L^(1)with 1,2,4-triazole side chains exhibited the highest selectivity for Am(Ⅲ)over Eu(Ⅲ)while the lowest complexation ability for metal ions among the three pyridine-derived polyazole ***,we designed a new ligand L^(4)con-taining 1,2,4-triazole side chains and a preorganized phenanthroline ***,such a new ligand was verified to show stronger complexation ability and higher selectivity for Am(Ⅲ)/Eu(Ⅲ)ions than L^(1).This work clarifies the complexation nature of polyazole based ligands with Am(Ⅲ)/Eu(Ⅲ)ions and provides design strategies for highly efficient polyazole based ligands for An(Ⅲ)/Ln(Ⅲ)separation.

关键词： Solvent extraction Am(Ⅲ)/Eu(Ⅲ)separation Polyazole based ligands Design strategy Density functional theory

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Optical colorimetric LiTaO_(3)wafers for highprecision lithography on frequency control of SAW devices

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Photonics Research 2024年第2期12卷 341-349页

作者： MING HUI fang YINONG XIE fangQI XUE ZHILIN wu JUN shi SHENG YU YANG YILIN LIU ZHIHUANG LIU HSIN CHI WANG FAJUN LI QING HUO LIU JINFENG ZHU School of Electronic Science and Engineering Xiamen UniversityXiamen 361005China Quanzhou San’an Integrated Circuit Co. Ltd.Quanzhou 362300China Eastern Institute of Technology Ningbo 315200China

Surface acoustic wave(SAW)resonators based on lithium tantalate(LT,LiTaO_(3))wafers are crucial elements of mobile communication *** use of intrinsic LT wafers typically brings about low fabrication accuracy of SAW resonators due to strong UV reflection in the lithography *** hinders their resonance frequency control seriously in industrial *** doping and chemical reduction could be applied to decrease the UV reflection of LT wafers for high lithographic ***,conventional methods fail to provide a fast and nondestructive approach to identify the UV performance of standard single-side polished LT wafers for highprecision frequency ***,we propose a convenient on-line sensing scheme based on the colorimetry of reduced Fe-doped LT wafers and build up an automatic testing system for industrial *** levels of Fe doping and chemical reduction are evaluated by the lightness and color difference of LT-based *** correlation between the wafer visible colorimetry and UV reflection is established to refine the lithography process and specifically manipulate the frequency performance of SAW *** study provides a powerful tool for the fabrication control of SAW resonators and will inspire more applications on sophisticated devices of mobile communication.

关键词： lithography doping wafer

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Permeable and robust polymer-silica hybrid armor on cell catalyst for sustainable biomanufacturing

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Particuology 2024年第9期92卷 106-112页

作者： Yiran Cheng Zhenhua wu Boyu Zhang Jiaxu Zhang Jiafu shi Zhongyi Jiang School of Environmental Science and Engineering Tianjin UniversityTianjin300072China Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China

Inactivated cell catalysis is one of several central techniques in green biomanufacturing ***,the instability and leakage of enzymes in inactivated cell severely restrict the practical applications of inactivated cell *** armor on the surface of inactivated cells affords a feasible and effective strategy to enhance the stability of cells while commonly lowering the ***,polymer-silica hybrid armor(PSHA)is directly generated on the surface of enzyme-containing *** branched structure of PEI enables higher porosity of cell@PSHA,exhibiting 1.52-fold enhancement in substrate permeability by contrast with cell@silica armor(SA).The electrostatic interactions(NH_(3)^(+)with O^(−))and hydrogen bonding(N⋯H or O⋯H)interactions between structural units enables higher stability of cell@PSHA,showing 3.13-fold elevation in Young's modulus compared with cell@*** a result,the cell@PSHA can catalyze continuous conversion of starch to tagatose for 15 batches over 969 h,with an average yield of 77.76 g L^(−1).

关键词： Biomanufacturing Wholecell catalysis Polymer-silica hybrid armor Tagatose production Starch conversion

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Asynchronous Learning-Based Output Feedback Sliding Mode Control for Semi-Markov Jump Systems: A Descriptor Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1358-1369页

作者： Zheng wu Yiyun Zhao Fanbiao Li Tao Yang Yang shi Weihua Gui School of Automation Central South UniversityChangsha 410083China Power Electronics Machines and Control GroupThe University of NottinghamNottingham NG72RDUK Department of Mechanical Engineering University of VictoriaVictoria BC V8W 3P6Canada IEEE

This paper presents an asynchronous output-feed-back control strategy of semi-Markovian systems via sliding mode-based learning *** with most literature results that require exact prior knowledge of system state and mode information,an asynchronous output-feedback sliding sur-face is adopted in the case of incompletely available state and non-synchronization *** holonomic dynamics of the sliding mode are characterized by a descriptor system in which the switching surface is regarded as the fast subsystem and the system dynamics are viewed as the slow *** upon the co-occurrence of two subsystems,the sufficient stochastic admissibility criterion of the holonomic dynamics is derived by utilizing the characteristics of cumulative distribution ***,a recursive learning controller is formulated to guarantee the reachability of the sliding manifold and realize the chattering reduction of the asynchronous switching and sliding ***,the proposed theoretical method is substantia-ted through two numerical simulations with the practical contin-uous stirred tank reactor and F-404 aircraft engine model,respectively.

关键词： Asynchronous switching learning-based control output feedback semi-Markovian jump systems sliding mode con-trol(SMC).

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Hole mobility enhancement in monolayer WSe2 p-type transistors through molecular doping

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Science China(Information Sciences) 2024年第6期67卷 207-213页

作者： shiyuan LIU Xiong XIONG Xin WANG Xinhang shi Ru HUANG Yanqing wu School of Integrated Circuits and Beijing Advanced Innovation Center for Integrated Circuits Peking University wuhan National High Magnetic Field Center and School of Integrated Circuits Huazhong University of Science and Technology

Two-dimensional （2D） transition metal dichalcogenide （TMDC） semiconductor materials exhibit extraordinary electrical properties,holding promise for the realization of next-generation complementary metal-oxide-semiconductor （CMOS） devices at ultimate ***,constrained by effective device doping strategies,the hole mobility and device performance of tungsten diselenide （WSe2） p-type transistors,especially monolayer chemical vapor deposition （CVD）-grown WSe2,have not met *** this paper,an effective performance enhancement of monolayer WSe2p-type transistor was achieved through a molecular doping *** monolayer WSe2directly on SiO2back-gated substrates and leveraging energy band alignment design,4-nitrobenzenediazonium tetrafluoroborate （4-NBD） molecular dopant with a concentration of 10 m M was utilized to modulate the Fermi level position of monolayer WSe2for hole *** devices demonstrated a more than 98%increase in hole mobility,reaching up to 97 cm2·V-1·s-1while maintaining the current on/off ratio of *** p-type WSe2transistors with 1μm channel length exhibit a high drive current surpassing 176μA·μm-1,exceeding previous CVD-WSe2devices with similar channel *** straightforward and effective approach to improving the electrical performance of WSe2transistors paves the way for advanced logic technologies based on transition metal dichalcogenide semiconductors.

关键词： CVD-grown WSe$_2$ molecular doping 4-NBD p-type transistors hole mobility

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Real-time UAV path planning based on LSTM network

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Journal of Systems Engineering and Electronics 2024年第2期35卷 374-385页

作者： ZHANG Jiandong GUO Yukun ZHENG Lihui YANG Qiming shi Guoqing wu Yong School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China The Flight Automatic Control Research Institute of AVIC Xi’an 710065China Military Representative Office of Marine wuhan Bureau in Luoyang Area Luoyang 471000China

To address the shortcomings of single-step decision making in the existing deep reinforcement learning based unmanned aerial vehicle(UAV)real-time path planning problem,a real-time UAV path planning algorithm based on long shortterm memory(RPP-LSTM)network is proposed,which combines the memory characteristics of recurrent neural network(RNN)and the deep reinforcement learning *** networks are used in this algorithm as Q-value networks for the deep Q network(DQN)algorithm,which makes the decision of the Q-value network has some *** to LSTM network,the Q-value network can use the previous environmental information and action information which effectively avoids the problem of single-step decision considering only the current ***,the algorithm proposes a hierarchical reward and punishment function for the specific problem of UAV real-time path planning,so that the UAV can more reasonably perform path *** verification shows that compared with the traditional feed-forward neural network(FNN)based UAV autonomous path planning algorithm,the RPP-LSTM proposed in this paper can adapt to more complex environments and has significantly improved robustness and accuracy when performing UAV real-time path planning.

关键词： deep Q network path planning neural network unmanned aerial vehicle(UAV) long short-term memory(LSTM)

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