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Mechanism of a dual-phase Ti-Nb alloy exhibiting near-linear elastic deformation

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Rare Metals 2024年第5期43卷 2282-2289页

作者： Yan Guo Wang Ding Wen Ma Shun Guo hao-Dong Meng Nian-Yao xu School of Automotive Engineering Changzhou Institute of TechnologyChangzhou 213032China School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China Youke Publishing Co. LtdChina Grinm Group Co.LtdBeijing 100088China

In this work,the underlying mechanism responsible for the near-linear elastic deformation behavior of a dual-phase Ti-Nb alloy consisting of β and α'' phase with large recoverable strain was systematically *** on in situ synchrotron X-ray diffraction(SXRD)analyses,it was found that besides intrinsic elastic deformation,a slight reversible β-α'' stress-induced martensitic(SIM)transformation,which proceeded in a consecutive mode under the retarding effect of micro-defects,took place during the near-linear elastic *** unloading,a small amount of residual macroscopic strain remained in the specimen due to the incomplete reverse α''→β transformation on *** high near-linear elastic deformability of the cold drawing(CD)Ti-Nb alloy has been revealed to be attributed to the coupling actions of intrinsic elasticity as well as the consecutive and reversible β-α'' SIM *** research may contribute to a new avenue for the design and development of novel dual-phase Ti-based alloys with desirable elastic deformability.

关键词： Titanium alloys Dual-phase Near-linear elastic deformation Martensitictransformation

Atmospheric iron deposition in a megacity of northwest China:Solubility,speciation,and deposition fluxes

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Particuology 2024年第7期90卷 383-393页

作者： Xiaotao Yang Pingping Liu Zhiwei xue hao Zhang xuan Li Hongmei xu Zhenxing Shen Department of Environmental Science and Engineering Xi'an Jiaotong UniversityXi'anChina State Key Laboratory of Loess and Quaternary National Key R&D of China Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'anChina No.203 Research Institute of Nuclear Industry Xi'an710086China Xi'an Environmental Monitoring Station Xi'an 710054China

Atmospheric iron has crucial effects on biogeochemical cycles,atmospheric processing,global climate,and human *** this study,atmospheric dustfall samples were collected from six functional areas in Xi'an,China,from 2020 to *** spatiotemporal distributions and deposition fluxes of total and water-soluble(ws)Fe as well as the speciation and potential sources of ws-Fe were *** areas had the highest concentrations of total Fe and ws-Fe,which were mainly due to copious emissions of heavy metals during *** total Fe concentrations peaked in spring,primarily due to the substantial input of crustal dust,which also led to the lowest Fe solubility in this *** contrast,the highest levels of ws-Fe occurred during winter due to an increase in biomass *** the water-soluble forms,ws-Fe(II)was dominant and accounted for 74.8%of the total amount of *** dust was the main contributor to total Fe,whereas biomass burning primarily contributed to peak ws-Fe *** average total and ws-Fe deposition fluxes in Xi'an were the highest in spring and lowest in autumn,which were related to the distributions of the dustfall deposition fluxes and their Fe contents during these *** study provided a broader and comprehensive understanding of atmospheric iron deposition in Chinese urban area,which is of positive significance for understanding atmospheric chemistry and global climate change.

关键词： Atmospheric dustfall Iron Speciation distribution Seasonal variation Functional area Sources

Non-contact and full-field online monitoring of curing temperature during the in-situ heating process based on deep learning

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Advances in Manufacturing 2024年第1期12卷 167-176页

作者： Qiang-Qiang Liu Shu-Ting Liu Ying-Guang Li xu Liu Xiao-Zhong hao College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing210016People’s Republic of China School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing211816People’s Republic of China

Online monitoring of the curing temperature field is essential to improving the quality and efficiency of the manufacturing process of composite *** embedded sensor-based technologies have difficulty monitoring the full temperature field or have to introduce heterogeneous items that could have an undesired impact on the *** this paper,a non-contact,full-field monitoring method based on deep learning that predicts the internal temperature field of composite parts in real time using surface temperature measurements of auxiliary materials is *** the proposed method,an average temperature monitoring accuracy of 97%is achieved in various heating *** addition,this method also demonstrates satisfying feasibility when a stronger thermal barrier covers the *** method was experimentally validated during the self-resistance electric heating process,in which the monitoring accuracy reached 93.1%.This method can potentially be applied to automated manufacturing and process control in the composites industry.

关键词： Online monitoring Curing temperature field Deep learning(DL) In-situ heating

Hybrid bonding of GaAs and Si wafers at low temperature by Ar plasma activation

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Journal of Semiconductors 2024年第4期45卷 69-75页

作者： Rui Huang Zhiyong Wang Kai Wu hao xu Qing Wang Yecai Guo School of Electronic and Information Engineering Wuxi UniversityWuxi 214105China Institute of Advanced Technology on Semiconductor Optics&Electronics Institute of Laser EngineeringBeijing University of TechnologyBeijing 100124China

High-quality bonding of 4-inch GaAs and Si is achieved using plasma-activated bonding *** influence of Ar plasma activation on surface morphology is *** the annealing temperature is 300℃,the bonding strength reaches a maximum of 6.2 *** addition,a thermal stress model for GaAs/Si wafers is established based on finite element analysis to obtain the distribution of equivalent stress and deformation variables at different *** shape varia-tion of the wafer is directly proportional to the annealing *** an annealing temperature of 400℃,the maximum protrusion of 4 inches GaAs/Si wafers is 3.6 *** interface of GaAs/Si wafers is observed to be dense and defect-free using a transmission electron *** characterization of interface elements by X-ray energy dispersion spectroscopy indi-cates that the elements at the interface undergo mutual diffusion,which is beneficial for improving the bonding strength of the *** is an amorphous transition layer with a thickness of about 5 nm at the bonding *** preparation of Si-based GaAs heterojunctions can enrich the types of materials required for the development of integrated circuits,improve the performance of materials and devices,and promote the development of microelectronics technology.

关键词： plasma-activated bonding bonding strength thermal stress model mutual diffusion

Physical-Layer Secret Key Generation for Dual-Task Scenarios

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China Communications 2024年第7期21卷 252-266页

作者： Yang Lilin Li Guyue Guo Tao xu hao Hu Aiqun School of Cyber Science and Engineering Southeast UniversityNanjing 210096China Purple Mountain Laboratories Nanjing 210096China Department of Electronic and Electrical Engineering University College LondonLondon WC1E 7JEUK National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China

Physical-layer secret key generation(PSKG)provides a lightweight way for group key(GK)sharing between wireless users in large-scale wireless ***,most of the existing works in this field consider only group *** a commonly dual-task scenario,where both GK and pairwise key(PK)are required,traditional methods are less suitable for direct *** the first time,we discover a security issue with traditional methods in dual-task scenarios,which has not previously been *** propose an innovative segment-based key generation method to solve this security *** do not directly use PK exclusively to negotiate the GK as traditional ***,we generate GK and PK separately through segmentation which is the first solution to meet *** also perform security and rate *** is demonstrated that our method is effective in solving this security issue from an information-theoretic *** rate results of simulation are also consistent with the our rate derivation.

关键词： dual-task scenario information-theoretic security physical layer security secret group key generation

Simulation of the Ecosystem Productivity Responses to Aerosol Diffuse Radiation Fertilization Effects over the Pan-Arctic during 2001–19

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Advances in Atmospheric Sciences 2024年第1期41卷 84-96页

作者： Zhiding ZHANG xu YUE hao ZHOU Jun ZHU Yadong LEI Chenguang TIAN Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&Technology(NUIST)Nanjing 210044China Climate Change Research Center Institute of Atmospheric Physics(IAP)Chinese Academy of Sciences(CAS)Beijing 100029China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of CMA Chinese Academy of Meteorological SciencesBeijing 100081China

The pan-Arctic is confronted with air pollution transported from lower *** have shown that aerosols help increase plant photosynthesis through the diffuse radiation fertilization effects(DRFEs).While such DRFEs have been explored at low to middle latitudes,the aerosol impacts on pan-Arctic ecosystems and the contributions by anthropogenic and natural emission sources remain less ***,we perform regional simulations at 0.2o×0.2ousing a well-validated vegetation model(Yale Interactive terrestrial Biosphere,YIBs)in combination with multi-source of observations to quantify the impacts of aerosol DRFEs on the net primary productivity(NPP)in the pan-Arctic during *** show that aerosol DRFEs increase pan-Arctic NPP by 2.19 Pg C(12.8%)yr^(-1)under clear-sky conditions,in which natural and anthropogenic sources contribute to 8.9% and 3.9%,*** all-sky conditions,such DRFEs are largely dampened by cloud to only 0.26 Pg C(1.24%)yr^(-1),with contributions of 0.65% by natural and 0.59% by anthropogenic *** aerosols cause a positive NPP trend of 0.022% yr^(-1)following the increased fire activities in the *** contrast,anthropogenic aerosols induce a negative trend of-0.01% yr^(-1)due to reduced emissions from the middle *** trends in aerosol DRFEs show a turning point in the year of 2007 with more positive NPP trends by natural aerosols but negative NPP trends by anthropogenic aerosols *** affected by modeling uncertainties,this study suggests a likely increasing impact of aerosols on terrestrial ecosystems in the pan-Arctic under global warming.

关键词： diffuse radiation fertilization effects anthropogenic aerosols natural aerosols pan-Arctic net primary productivity

Pt confined in Sn-ECNU-46 zeolite for efficient alkane dehydrogenation

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Chinese Journal of Structural Chemistry 2024年第4期43卷 15-23页

作者： Naihong Wang Longkang Zhang Yejun Guan Peng Wu hao xu Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal UniversityShanghai200062China State Key Laboratory of Petroleum Molecular&Process Engineering SKLPMPE Sinopec Research Institute of Petroleum Processing Co.LTD.Beijing100083China East China Normal University Shanghai200062China

Highly dispersed and stable Pt-based catalysts play a crucial role in constructing efficient catalytic systems for alkane *** this study,a novel bimetallic Pt-Sn catalyst confined in extra-large-pore ECNU-46 zeolite(denoted as Pt/Sn-ECNU-46)is prepared by *** open-site framework Sn species((SiO)_(3)Sn-OH)serve as anchors to interact with Pt species,favoring the high dispersion of *** the other hand,the framework Sn species act as the second metal to regulate the geometrical and electronic environment of Pt species,thus suppressing their ***/Sn-ECNU-46 achieves a good performance in propane dehy-drogenation(PDH)reaction with high initial propane conversion(46%)and propylene selectivity(>99%)as well as regeneration *** addition,Pt/Sn-ECNU-46 is also active in the dehydrogenation of *** study explores the application of extra-large-pore zeolite as support in constructing metal-confined catalysts for alkane dehydrogenation.

关键词： Alkane dehydrogenation Heteroatom-containing zeolite Zeolite confined catalyst Pt-based catalyst

Real-time Abnormal Detection of GWAC Light Curve based on Wavelet Transform Combined with GRU-Attention

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Research in Astronomy and Astrophysics 2024年第5期24卷 151-168页

作者： hao Li Qing Zhao Long Shao Tao Liu Chenzhou Cui Yunfei xu College of Artifcial Intelligence Tianjin University of Science and TechnologyTianjin 300457China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

Nowadays, astronomy has entered the era of Time-Domain Astronomy, and the study of the time-varying light curves of various types of objects is of great significance in revealing the physical properties and evolutionary history of celestial bodies. The Ground-based Wide Angle Cameras telescope, on which this paper is based, has observed more than 10 million light curves, and the detection of anomalies in the light curves can be used to rapidly detect transient rare phenomena such as microgravity lensing events from the massive data. However, the traditional statistically based anomaly detection methods cannot realize the fast processing of massive data. In this paper, we propose a Discrete Wavelet(DW)-Gate Recurrent Unit-Attention(GRU-Attention) light curve warning model. Wavelet transform has good effect on data noise reduction processing and feature extraction, which can provide richer and more stable input features for a neural network, and the neural network can provide more flexible and powerful output model for wavelet transform. Comparison experiments show an average improvement of 61% compared to the previous pure long-short-term memory unit(LSTM) model, and an average improvement of 53.5% compared to the previous GRU model. The efficiency and accuracy of anomaly detection in previous paper work are not good enough, the method proposed in this paper possesses higher efficiency and accuracy,which incorporates the Attention mechanism to find out the key parts of the light curve that determine the anomalies. These parts are assigned higher weights, and in the actual anomaly detection, the star is detected with83.35% anomalies on average, and the DW-GRU-Attention model is compared with the DW-LSTM model, and the detection result f1 is improved by 5.75% on average, while having less training time, thus providing valuable information and guidance for astronomical observation and research.

关键词： methods data analysis-stars variables general-techniques photometric

Microstructure homogeneity and mechanical properties of laser-arc hybrid welded AZ31B magnesium alloy

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Journal of Magnesium and Alloys 2024年第5期12卷 1986-1995页

作者： Yongkang Gao Kangda hao Lianyong xu Yongdian Han Lei Zhao Wenjing Ren Hongyang Jing School of Materials Science and Engineering Tianjin UniversityTianjin 300350PR China Tianjin Key Laboratory of Advanced Joining Technology Tianjin 300350PR China

Laser-arc hybrid welding of AZ31B magnesium alloy was carried out,the effects of welding parameters on weld formation,microstructure homogeneity and mechanical properties were *** results showed that laser-arc hybrid welding was beneficial to improve the weld formation of magnesium alloy by inhibiting the defect of undercut and *** weld microstructure was mainly columnar grains neighboring the fusion line and equiaxed grains at the weld *** was interesting that the grain size at the upper arc zone was smaller than that at the lower laser zone,with the difference mainly affected by laser power rather than welding current and welding *** welding parameters were optimized as laser power of 3.5 kW,welding current of 100 A and welding speed of 1.5 m/*** this case,the weld was free of undercut and pores,and the tensile strength and elongation rate reached 252 MPa and 11.2%,***,the microstructure homogeneity was illustrated according to the heat distribution,and the evolution law of tensile properties was discussed basing on the weld formation and microstructure characteristics.

关键词： Magnesium alloy Laser-arc hybrid welding Microstructure homogeneity Mechanical properties