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Printability disparities in heterogeneous material combinations via laser directed energy deposition:a comparative study

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International Journal of Extreme manufacturing 2024年第2期6卷 389-405页

作者： Jinsheng Ning Lida Zhu Shuhao Wang Zhichao Yang Peihua Xu Pengsheng Xue Hao Lu Miao Yu Yunhang Zhao Jiachen Li Susmita Bose Amit Bandyopadhyay School of Mechanical engineering and automation Northeastern UniversityShenyang 110819People’s Republic of China School of Machinery and automation Wuhan University of Science and TechnologyWuhan 430081People’s Republic of China School of Mechanical engineering Xi’an University of Science and TechnologyXi’an 710054People’s Republic of China Beijing Institute of Space Launch Technology Beijing 100076People’s Republic of China W.M.Keck Biomedical Materials Research Lab School of Mechanical and Materials EngineeringWashington State UniversityPullmanWA 99164United States of America

Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final *** is essential to understand the underlying printability of different material combinations based on an adapted ***,the printability disparities of two common and attractive material combinations(nickel-and iron-based alloys)are evaluated at the macro and micro levels via laser directed energy deposition(DED).The deposition processes were captured using in situ high-speed imaging,and the dissimilarities in melt pool features and track morphology were quantitatively investigated within specific process ***,the microstructure diversity of the tracks and blocks processed with varied material pairs was comparatively elaborated and,complemented with the informative multi-physics modeling,the presented non-uniformity in mechanical properties(microhardness)among the heterogeneous material pairs was *** differences in melt flow induced by the unlike thermophysical properties of the material pairs and the resulting element intermixing and localized re-alloying during solidification dominate the presented dissimilarity in printability among the material *** work provides an in-depth understanding of the phenomenological differences in the deposition of dissimilar materials and aims to guide more reliable DED forming of bimetallic parts.

关键词： directed energy deposition printability microstructure microhardness bimetallic parts

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反向连边在大型分层网络中的影响（英文）

engineering 2024年第5期 240-249页

作者：曹浩森胡斌斌莫小雨陈都鑫高建喜袁烨陈关荣 Tamás Vicsek 管晓宏张海涛 MOE engineering Research Center of Autonomous Intelligent Unmanned Systems State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Artificial Intelligence and Automation Huazhong University of Science and Technology School of Mechanical and Aerospace engineering Nanyang Technological University Jiangsu Key Laboratory of Networked Collective Intelligence School of Mathematics Southeast University Department of Computer Science Rensselaer Polytechnic Institute Department of Electronic engineering City University of Hong Kong Department of Biological Physics E?tv?s University MOE Key Laboratory for Intelligent Networks and Network Security School of Automation Science and Engineering Xi'an Jiaotong University

Hierarchical networks are frequently encountered in animal groups, gene networks, and artificial engineering systems such as multiple robots, unmanned vehicle systems, smart grids, wind farm networks,and so forth. The structure of a large directed hierarchical network is often strongly influenced by reverse edges from lower-to higher-level nodes, such as lagging birds' howl in a flock or the opinions of lowerlevel individuals feeding back to higher-level ones in a social group. This study reveals that, for most large-scale real hierarchical networks, the majority of the reverse edges do not affect the synchronization process of the entire network; the synchronization process is influenced only by a small part of these reverse edges along specific paths. More surprisingly, a single effective reverse edge can slow down the synchronization of a huge hierarchical network by over 60%. The effect of such edges depends not on the network size but only on the average in-degree of the involved subnetwork. The overwhelming majority of active reverse edges turn out to have some kind of ‘‘bunchingo effect on the information flows of hierarchical networks, which slows down synchronization processes. This finding refines the current understanding of the role of reverse edges in many natural, social, and engineering hierarchical networks,which might be beneficial for precisely tuning the synchronization rhythms of these networks. Our study also proposes an effective way to attack a hierarchical network by adding a malicious reverse edge to it and provides some guidance for protecting a network by screening out the specific small proportion of vulnerable nodes.

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Bidirectional position attention lightweight network for massive MIMO CSI feedback

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The Journal of China Universities of Posts and Telecommunications 2024年

作者： Li Jun Wang Yukai Zhang Zhichen He Bo Zheng Wenjing Lin Fei School of Information Science and engineering Shandong University School of Information and automation Qilu University of Technology (Shandong Academy of Sciences)

In frequency-division duplex massive multiple-input multiple-output (MIMO) systems， a bidirectional positional attention network (BPANet) is proposed to address the high computational complexity and low accuracy of existing deep learning-based channel state information (CSI) feedback methods. Specifically， a bidirectional position attention module (BPAM) is designed in the proposed BPANet to improve the network performance. The BPAM captures the distribution characteristics of the CSI matrix by integrating channel and spatial dimension information， thereby enhancing the feature representation of the CSI matrix. Furthermore， channel attention is decomposed into two one-dimensional feature encoding processes， which effectively reduce computational costs. Simulation results demonstrate that， compared with the existing representative method CLNet， BPANet reduces computational complexity by an average of 19.4% and improves accuracy by an average of 7.1%. Additionally， it performs better in terms of running time delay and cosine similarity.

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使用深度学习在CTA扫描卷下实现主动脉夹层分类和直径测量的双功能系统

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engineering 2024年第3期34卷 83-91页

作者： Zhihui Huang Rui Wang Hui Yu Yifan Xu Cheng Cheng Guangwei Wang Haosen Cao Xiang Wei Hai-Tao Zhang School of Artificial Intelligence and automation&the MOE engineering Research Center of Autonomous Intelligent Unmanned Systems&the State Key Laboratory of Intelligent manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China division of Cardiovascular Surgery Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Wuhan Children’s Hospital:Wuhan Women and Children Medical Care Center Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430010China

Acute aortic dissection is one of the most life-threatening cardiovascular diseases,with a high mortality *** prevalence ranges from 0.2%to 0.8%in humans,resulting in a significant number of deaths due to being missed in manual *** importantly,the aortic diameter—a critical indicator for surgical selection—significantly influences the outcomes of surgeries ***,it is an urgent yet challenging mission to develop an automatic aortic dissection diagnostic system that can recognize and classify the aortic dissection type and measure the aortic *** paper offers a dual-functional deep learning system called aortic dissections diagnosis-aiding system(DDAsys)that enables both accurate classification of aortic dissection and precise diameter measurement of the *** this end,we created a dataset containing 61190 computed tomography angiography(CTA)images from 279 patients from the division of Cardiovascular Surgery at Tongji Hospital,Wuhan,*** dataset provides a slice-level summary of difficult-to-identify features,which helps to improve the accuracy of both recognition and *** system achieves a recognition F1 score of 0.984,an average classification F1 score of 0.935,and the respective measurement precisions for ascending and descending aortic diameters are 0.994 mm and 0.767 mm root mean square error(RMSE).The high consistency(88.6%)between the recommended surgical treatments and the actual corresponding surgeries verifies the capability of our system to aid clinicians in developing a more prompt,precise,and consistent treatment strategy.

关键词： Aortic dissections Computed tomography angiography Classification Deep learning

In-process adaptive milling for large-scale assembly interfaces of a vertical tail driven by real-time vibration data

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Chinese Journal of Aeronautics 2022年第5期35卷 441-454页

作者： Xiong ZHAO Lianyu ZHENG Lu YU School of Mechanical engineering and automation Beihang UniversityBeijing 100191China C919 division Shanghai Aircraft Manufacturing Co.LtdShanghai 201324China

Assembly interfaces,the joint surfaces between the vertical tail and rear fuselage of a large aircraft,are thin-wall *** machining quality are seriously restricted by the machining *** address this problem,an in-process adaptive milling method is proposed for the large-scale assembly interface driven by real-time machining vibration *** this context,the milling operation is first divided into several process steps,and the machining vibration data in each process step is separated into some data ***,based on the real-time machining vibration data in each data segment,a finite-element-unit-force approach and an optimized space–time domain method are adopted to estimate the time-varying in-operation frequency response functions of the assembly *** FRFs are in turn employed to calculate stability lobe ***,the three-dimensional stability lobe diagram considering material removal is acquired via interpolation of all stability lobe ***,to restrain milling chatter and resonance,the cutting parameters for next process step,e.g.,spindle speed and axial cutting depth,are optimized by genetic ***,the proposed method is validated by a milling test of the assembly interface on a vertical tail,and the experimental results demonstrate that the proposed method can improve the machining quality and efficiency of the assembly interface,i.e.,the surface roughness reduced from 3.2μm to 1.6μm and the machining efficiency improved by 33%.

关键词： Adaptive milling Assembly interfaces Data-driven Time-varying frequency response function Vertical tail

Novel concept of tailorable magnetic field and electron pressure distribution in a magnetic nozzle for effective space propulsion

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Propulsion and Power Research 2023年第1期12卷 59-68页

作者： Lohit Malik Department of manufacturing processes and automation engineering Netaji Subhas University of Technology(formerly Netaji Subhas Institute of Technology)New DelhiIndia Department of Mechanical and Aerospace engineering Princeton UniversityPrincetonNJ 08540United States

Magnetic nozzle appears to be a practical solution for prolonged space *** efficient handling of the spaceship,an in-flight solution to customize the thrust from the magnetic nozzle is *** a new concept of three-thick coils system is proposed for tailoring the magnetic field in-flight in accordance with electron pressure *** role of peak position of the pressure and its axial gradient is also uncovered for realizing higher *** three-fold increase in thrust is observed when the electron temperature is raised to w2.5 times of its original value at the exit *** set-up is optimized for its best performance and efficient use in the electric space propulsion sector with thrust approaching 5 *** particular,this can contribute to the attitude control or the precision pointing of the spacecraft,the technology for removal of space debris and manipulating the ion momentum flux lost to a wall or unsteady laser produced plasma flow in a magnetic nozzle.

关键词： Tailorable magnetic field Magnetic nozzle Electron pressure Thrust Effective space propulsion

Tapered coils system for space propulsion with enhanced thrust: a concept of plasma detachment

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Propulsion and Power Research 2022年第2期11卷 171-180页

A concept for plasma detachment in a magnetic nozzle is developed based on the detachment region which is found to decrease with the taper angle of the coils employed in the proposed flexible three coil *** tapering the coils while resulting in the same crosssectional area,the plasma plume outside the throat grows radially that leads to an enhancement in the thrust from 2.67 mN to 5 mN at the final detachment plane for a rise in the taper angle from 0 to 13.The maximum thrust can reach about 9 mN when the middle coil is shifted closer to the right coil along with increasing middle-to-outer-coil diameter(inner)ratio from 1 to *** three-tapered-coils arrangement for a magnetic nozzle turns out to be a robust candidate for space propulsion offering the ability to control plasma detachment and tune thrust in-flight simply via mechanical movements without changing the current.

关键词： Tapered coil Magnetic field topology Magnetic nozzle Thrust Plasma detachment Space propulsion

Data-Driven Fault Compensation Tracking Control for Coupled Wastewater Treatment Process

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IEEE/CAA Journal of Automatica Sinica 2023年第1期10卷 294-297页

作者： Peihao Du Weimin Zhong Xin Peng Linlin Li Zhi Li the Key Laboratory of Smart manufacturing in Energy Chemical Process Ministry of EducationEast China University of Science and TechnologyShanghai 200237China IEEE the Key Laboratory of Knowledge automation for Industrial processes of Ministry of Education the School of Automation and Electrical EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Dear Editor, This letter is concerned with the data-driven fault compensation tracking control for a coupled wastewater treatment process(WWTP)subject to sensor faults. Invariant set theory is introduced to eliminate the completely bounded and differentiable conditions of coupled non-affine dynamics and to explicitly express the control *** adaptive fault compensation mechanism is constructed to accommodate the effects of sensor faults. By employing a cubic absolutevalue Lyapunov criteria。

关键词： differentiable eliminate absolute

Effect of varying spatial orientations on build time requirements for FDM process: A case study

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Defence Technology（防务技术） 2017年第2期13卷 92-100页

作者： Sandeep Rathee Manu Srivastava Sachin Maheshwari Arshad Noor Siddiquee division of manufacturing processes and automation engineering Netaji Subhas Institute of Technology Department of Mechanical engineering Jamia Millia Islamia A Central University

In this research, effect of varying spatial orientations on the build time requirements for fused deposition modelling process is studied. Constructive solid geometry cylindrical primitive is taken as work piece and modeling is accomplished for it. Response surface methodology is used to design the experiments and obtain statistical models for build time requirements corresponding to different orientations of the given primitive in modeller build volume. Contour width, air gap, slice height, raster width, raster angle and angle of orientation are treated as process parameters. Percentage contribution of individual process parameter is found to change for build time corresponding to different spatial orientations. Also, the average of build time requirement changes with spatial orientation. This paper attempts to clearly discuss and describe the observations with an aim to develop a clear understanding of effect of spatial variations on the build time for Fused Deposition Modelling process. This work is an integral part of process layout optimization and these results can effectively aid designers specially while tackling nesting issues.

关键词： Fused deposition modeling Spatial orientation Process parameters Response Surface Methodology Build time