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Fast strength-ductility synergistically adjusting of cold spray additive manufactured Cu deposits via electric pulse processing

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Chinese Journal of Aeronautics 2024年第5期37卷 558-569页

作者： Dong WU Yaxin XU Wenya LI Xiawei YANG Yu su State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Friction Welding Technologies School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

Electric Pulse Processing(EPP)treatment was innovatively introduced to optimize the strength and ductility of the CSAMed Cu *** results show that EPP is an efficient and fast post-treatment to improve the strength and ductility(within tens of seconds).The larger the pulse current and number of pulses,the better the mechanical ***,this research found that when the heat input determined by pulse current and number of pulses exceeds a certain threshold(pulse current intensity is 2000 A,number of pulses is 10),increasing the number of repeat time could also effectively improve the mechanical properties.A tensile strength of 210 MPa and a ductility of 14.0%could be obtained with reasonable EPP parameters(pulse current intensity is 2000 A,number of pulses is 10,and repeat number is 2),which is similar to those of conventional annealing(e.g.,tensile strength is 272 MPa,elongation is 28.3%).The microstructure evolution analysis shows that EPP can effectively improve the bonding quality between the deposited particles by recrystallization,promote grain growth and the formation of twins,which is the main reason for the improvement of mechanical properties.

关键词： Cold spray additive manufacturing Copper deposit Mechanical property Electric pulse processing Post treatment

Effects of Interaction between Axial and Radial Secondary Air and Reductive Intensity in Reduction Region on Combustion Characteristics and NO_(x) Emission of Coal Preheated by a Self-Preheating Burner

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Journal of Thermal Science 2024年第1期33卷 249-267页

作者： su Kun DING Hongliang OUYANG Ziqu ZHANG Jinyang ZHU Shujun Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China

The study focused on the effects of the interaction between axial and radial secondary air and the reductive intensity in reduction region on combustion characteristics and NO_(x) emission in a 30 kW preheating combustion *** results revealed that the interaction and reductive intensity influenced the combustion in the down-fired combustor(DFC) and NO_(x) emission *** the temperature distribution,the interaction caused the position of the main combustion region to shift down as R_(2-12)(ratio of axial secondary air flow to radial secondary air flow) decreased or λ_(2)(total secondary air ratio) increased,and there was the interplay between both of their *** R_(3-12)(ratio of first-staged tertiary air flow to second-staged tertiary air flow)increased,the decrease in the reductive intensity also caused the above phenomenon,and the peak temperature increased in this *** the NO_(x) emission,the interaction affected the NO_(x) reduction adversely when λ_(2) or R_(2-12) was higher,and the range of this effect was larger,so that the NO_x emission increased obviously as they *** decrease in the reductive intensity caused the NO_(x) emission increased under the homogeneous reduction mechanism,while was unchanged at a high level under the heterogeneous reduction *** the combustion efficiency,the interaction improved the combustion efficiency as λ_(2) increased when R_(2-12) was lower,while reduced it as λ_(2) increased excessively when R_(2-12) was *** proper decrease in the reductive intensity caused the combustion efficiency increased obviously,while was hardly improved further when the intensity decreased *** this study,the lowest NO_(x) emission was only 41.75 mg/m^(3) without sacrificing the combustion efficiency by optimizing the interaction and reductive intensity.

关键词： self-preheating interaction of axial and radial secondary air reductive intensity combustion characteristic NO_(x)emission

Combustion and Self-desulfurization Characterization of Blended Low-Rank Coals for Improved Resource Utilization in Fluidized Bed Boilers

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Journal of Thermal Science 2024年第3期33卷 1242-1256页

作者： su Lipeng ZHANG Cong ZHANG Yongsheng WANG Tao WANG Jiawei Key Laboratory of Power Station Energy Transfer Conversion and System Ministry of EducationNorth China Electric Power UniversityBeijing102206China

The co-combustion of low-rank coals through fluidized bed boiler(CFB)is an effective approach to enhance the level of resource *** date,there has been a lack of investigation concerning the co-combustion kinetics and self-desulfurization characteristics of coal slime,coal gangue,and raw *** this study,we adopted multiple model-free and model-fitting methods to comparatively analyze co-combustion kinetics of blended coals on the basis of thermogravimetric ***,the sulfur balance and self-desulfurization of blended coals in the co-combustion were intensively investigated using a tube furnace *** results reveal that in the presence of coal gangue in blended coals,the average activation energy(E_(a))falls within the range of 65.7 kJ/mol to 100.4 kJ/mol,as determined by four model-free ***,in the absence of coal gangue,only the Flynn-Wall-Ozawa(FWO)and Friedman(FM)methods are deemed appropriate for calculating the average E_(a),yielding a value of 77.3 kJ/*** first order reaction model is confirmed to be reliable for analyzing the co-combustion kinetics of low-rank blended *** of the specific composition of the blended coal,a significant linear correlation exists between the Ea and the natural logarithm of the pre-exponential factor(lnA)within an extensive range of ***,the addition of coal gangue to the blended coal substantially enhances the self-desulfurization level,resulting in an increase from 25.7%to60.7%at 1073 *** self-desulfurization efficiency exhibits a good linear relationship with both the mass ratio of coal gangue to coal slime and the molar ratio of calcium to *** a practical implementation,the optimal addition ratio of coal gangue is a trade-off between the self-desulfurization efficiency and the ignition capacity.

关键词： coal slime coal gangue fluidized bed boilers self-desulfurization resource utilization

Small-sized Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C for efficient alkaline and acidic hydrogen evolution reaction by an anchoring calcination strategy

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 95-103页

作者： Jianxia Gu Ying Zhu Haiyan Zheng Chunyi sun Zhongmin su department of Chemistry Xinzhou Normal UniversityXinzhou 034000China School of Chemistry Northeast Normal UniversityChangchun 130024China

A novel,cheap and highly efficient Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C nanocomposite has been successfully constructed through simple one-step carbonization method in a nitrogen *** in the precursor can effectively anchor molybdenum-based Keggin-type polyoxometallate and NiCo-layered double hydroxide through electrostatic and coordination interactions,which avoids the aggregation of catalyst particles during the pyrolysis *** optimization,the obtained Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C possesses small size(3-8 nm),large specific surface area and hierarchical pore *** importantly,Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C presents remarkable hydrogen evolution reaction activity with low overpotentials in 0.5 mol·L^(-1)H_(2)SO_(4)(102.3 mV)and 1 mol·L^(-1)KOH(95 mV)to afford the current density of 10 mA·cm^(-2),as well as small Tafel slopes of 82.49 and 99.92 mV·dec^(-1),***,this catalyst also shows outstanding stability for 12 h without a significant change in current *** excellent catalytic performance of Ni-Co/Mo_(2)C/Co_(6)Mo_(6)C_(2)@C can put down to the synergistic effect between multiple components and the small size of the *** work provides unique insights into the preparation of efficient transition metal-based catalysts for HER.

关键词： polyoxometallates layered double hydroxide transition metal-based electrocatalysts hydrogen evolution reaction

Time-domain dynamic constitutive model suitable for mucky soil site seismic response

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 1-13页

作者： Dong Qing Chen su Jin Liguo Zhou Zhenghua Li Xiaojun Architectural Engineering Institute Huaiyin Institute of TechnologyHuai’an 223600China Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100020China Institute of Geophysics China Earthquake AdministrationBeijing 100089China College of Transportation Science and Engineering Nanjing Tech UniversityNanjing 211816China

Soil nonlinear behavior displays noticeable effects on the site seismic *** study proposes a new functional expression of the skeleton curve to replace the hyperbolic skeleton *** integrating shear modulus and combining the dynamic skeleton curve and the damping degradation coefficient,the constitutive equation of the logarithmic dynamic skeleton can be obtained,which considers the damping effect in a soil dynamics *** on the finite difference method and the multi-transmitting boundary condition,a 1D site seismic response analysis program called Soilresp1D has been developed herein and used to analyze the time-domain seismic response in three types of *** the same time,this study also provides numerical simulation results based on the hyperbolic constitutive model and the equivalent linear *** results verify the rationality of the new soil dynamic constitutive *** can analyze the mucky soil site nonlinear seismic response,reflecting the deformation characteristics and damping effect of the silty *** hysteresis loop area is more extensive,and the residual strain is evident.

关键词： seismic response time-domain dynamic constitutive model logarithmic dynamic skeleton dampening effect mucky soil

Adaptive Sensor-Fault Tolerant Control of Unmanned Underwater Vehicles With Input Saturation

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 907-918页

作者： Xuerao Wang Qingling Wang Yanxu su Yuncheng Ouyang Changyin sun the School of Artificial Intelligence the Engineering Research Center of Autonomous Unmanned System Technologyand the Anhui Provincial Engineering Research Center for Unmanned System and Intelligent TechnologyMinistry of EducationAnhui UniversityHefei 230601China the School of Automation Southeast UniversityNanjing 210096China

This paper investigates the tracking control problem for unmanned underwater vehicles(UUVs)systems with sensor faults,input saturation,and external disturbance caused by waves and ocean *** active sensor fault-tolerant control scheme is ***,the developed method only requires the inertia matrix of the UUV,without other dynamic information,and can handle both additive and multiplicative sensor ***,an adaptive fault-tolerant controller is designed to achieve asymptotic tracking control of the UUV by employing robust integral of the sign of error feedback *** is shown that the effect of sensor faults is online estimated and compensated by an adaptive *** the proposed controller,the tracking error and estimation error can asymptotically converge to ***,simulation results are performed to demonstrate the effectiveness of the proposed method.

关键词： Asymptotic stability fault-tolerant control input saturation robust integral of the sign of error unmanned underwater vehicle

Low-Rank Optimal Transport for Robust Domain Adaptation

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1667-1680页

作者： Bingrong Xu Jianhua Yin Cheng Lian Yixin su Zhigang Zeng IEEE the School of Automation Wuhan University of TechnologyWuhan 430070China Intelligent Transportation Systems Research Center Wuhan University of TechnologyWuhan 430063 Chongqing Research Institute Wuhan University of TechnologyChongqingChina the School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074 the Key Laboratory of Image Processing and Intelligent Control of Education Ministry of China Wuhan 430074China

When encountering the distribution shift between the source(training) and target(test) domains, domain adaptation attempts to adjust the classifiers to be capable of dealing with different domains. Previous domain adaptation research has achieved a lot of success both in theory and practice under the assumption that all the examples in the source domain are welllabeled and of high quality. However, the methods consistently lose robustness in noisy settings where data from the source domain have corrupted labels or features which is common in reality. Therefore, robust domain adaptation has been introduced to deal with such problems. In this paper, we attempt to solve two interrelated problems with robust domain adaptation:distribution shift across domains and sample noises of the source domain. To disentangle these challenges, an optimal transport approach with low-rank constraints is applied to guide the domain adaptation model training process to avoid noisy information influence. For the domain shift problem, the optimal transport mechanism can learn the joint data representations between the source and target domains using a measurement of discrepancy and preserve the discriminative information. The rank constraint on the transport matrix can help recover the corrupted subspace structures and eliminate the noise to some extent when dealing with corrupted source data. The solution to this relaxed and regularized optimal transport framework is a convex optimization problem that can be solved using the Augmented Lagrange Multiplier method, whose convergence can be mathematically proved. The effectiveness of the proposed method is evaluated through extensive experiments on both synthetic and real-world datasets.

关键词： Domain adaptation low-rank constraint noise corruption optimal transport

Localized CdS homojunctions with optimal ratio of high and low index facets to dynamically boost H_(2)O splitting into H_(2)energy

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Journal of Materials Science & Technology 2024年第4期171卷 94-100页

作者： Xiaojun Wang Yiqi Zhang Shujuan Jiang Jiakun su Shaoqing Song School of Materials Science&Chemical Engineering Ningbo UniversityNingbo 330013China School of New Energy Ningbo University of TechnologyNingbo 315336China Tchnology Center China Tobacco Jiangxi Industrial LLCNanchang 330096China

Localized CdS homojunctions with optimal ratio of high and low index facets are constructed to dy-namically boost H_(2)O splitting into H_(2)energy by hydrothermal method in combination with *** density functional theory,hall effect,and in situ diffuse reflectance infrared Fourier transform spec-troscopy,it is revealed that photo-irradiated e^(−)and h^(+)can be spatially separated and directionally trans-ferred to the reductive high-index facet{002}and oxidative low-index facet{110}of localized CdS homo-junction induced by Fermi level difference of both high and low index facets to dehydrogenate ^(∗)-OH and coupled ^(∗)-O intermediates for H_(2)and O_(2)yield,respectively,along with a solar conversion into hydrogen of 1.93%by AM 1.5 G irradiation at 65℃.The study work suggests a scientific perspective on the optimal ratio of high and low index facets to understand photo-generated charge carrier transfer dynamically and their photocatalytic principle for H_(2)O splitting reaction in kinetics.

关键词： Photocatalytic H_(2)evolution Homojunction Localized field Ratio of high low index facets In-situ DRIFTS

Redundant Data detection and deletion to Meet Privacy Protection Requirements in Blockchain-Based Edge Computing Environment

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China Communications 2024年第3期21卷 149-159页

作者： Zhang Lejun Peng Minghui su Shen Wang Weizheng Jin Zilong su Yansen Chen Huiling Guo Ran Sergey Gataullin Cyberspace Institute Advanced Technology Guangzhou UniversityGuangzhou 510006China College of Information Engineering Yangzhou UniversityYangzhou 225127China School Math&Computer Science Quanzhou Normal UniversityQuanzhou 362000China Computer Science department City University of Hong KongHong Kong 999077China School of Computer and Software Nanjing University of Information Science and TechnologyNanjing 21004China Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education School of Computer Science and TechnologyAnhui UniversityHefei 230601China department of Computer Science and Artificial Intelligence Wenzhou UniversityWenzhou 325035China Guangzhou University Library Guangzhou UniversityGuangzhou 510006China Central Economic and Mathematics Institute Russian Academy of Sciences MIREA-Russian Technological University Moscow RegionRussia

With the rapid development of information technology,IoT devices play a huge role in physiological health data *** exponential growth of medical data requires us to reasonably allocate storage space for cloud servers and edge *** storage capacity of edge nodes close to users is *** should store hotspot data in edge nodes as much as possible,so as to ensure response timeliness and access hit rate;However,the current scheme cannot guarantee that every sub-message in a complete data stored by the edge node meets the requirements of hot data;How to complete the detection and deletion of redundant data in edge nodes under the premise of protecting user privacy and data dynamic integrity has become a challenging *** paper proposes a redundant data detection method that meets the privacy protection *** scanning the cipher text,it is determined whether each sub-message of the data in the edge node meets the requirements of the hot *** has the same effect as zero-knowledge proof,and it will not reveal the privacy of *** addition,for redundant sub-data that does not meet the requirements of hot data,our paper proposes a redundant data deletion scheme that meets the dynamic integrity of the *** use Content Extraction Signature(CES)to generate the remaining hot data signature after the redundant data is *** feasibility of the scheme is proved through safety analysis and efficiency analysis.

关键词： blockchain data integrity edge computing privacy protection redundant data