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Super-resolution diffractive neural network for alloptical direction of arrival estimation beyond diffraction limits

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Light(Science & Applications) 2024年第8期13卷 1602-1614页

作者： Sheng Gao Hang Chen Yichen Wang Zhengyang Duan haiou zhang Zhi Sun Yuan Shen Xing Lin Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Wireless sensing of the wave propagation direction from radio sources lays the foundation for communication,radar,navigation,***,the existing signal processing paradigm for the direction of arrival estimation requires the radio frequency electronic circuit to demodulate and sample the multichannel baseband signals followed by a complicated computing process,which places the fundamental limit on its sensing speed and energy ***,we propose the super-resolution diffractive neural networks(S-DNN)to process electromagnetic(EM)waves directly for the DOA estimation at the speed of *** multilayer meta-structures of S-DNN generate super-oscillatory angular responses in local angular regions that can perform the all-optical DOA estimation with angular resolutions beyond the diffraction *** spatial-temporal multiplexing of passive and reconfigurable S-DNNs is utilized to achieve high-resolution DOA estimation over a wide field of *** S-DNN is validated for the DOA estimation of multiple radio sources over 5 GHz frequency bandwidth with estimation latency over two to four orders of magnitude lower than the state-of-the-art commercial devices in *** results achieve the angular resolution over an order of magnitude,experimentally demonstrated with four times,higher than diffraction-limited *** also apply S-DNN’s edge computing capability,assisted by reconfigurable intelligent surfaces,for extremely low-latency integrated sensing and communication with low power *** work is a significant step towards utilizing photonic computing processors to facilitate various wireless sensing and communication tasks with advantages in both computing paradigms and performance over electronic computing.

关键词： beyond optical network

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An Innovative Finite Element Geometric Modeling of Single-Layer Multi-Bead WAAMed Part

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2383-2401页

作者： Xiangman Zhou Jingping Qin Zichuan Fu Min Wang Youlu Yuan Junjian Fu haiou zhang Seyed Reza Elmi Hosseini College of Mechanical and Power Engineering China Three Gorges UniversityYichang443002China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan430074China School of Metallurgy and Materials Engineering Iran University of Science and TechnologyNarmakIran

Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead profilegeometric modeling method through the isosceles trapezoid function is proposed to build the FE model of theWAAMprocess. Firstly, a straight-line model for overlapping beads based on the parabola function was establishedto calculate the optimal center distance. Then, the isosceles trapezoid-based profile was employed to replace theparabola profiles of the parabola-based overlapping model to establish an innovative isosceles trapezoid-basedmulti-bead overlapping geometric model. The rationality of the isosceles trapezoid-based overlapping model wasconfirmed by comparing the geometric deviation and the heat dissipation performance index of the two overlappingmodels. In addition, the FE-coupled thermal-mechanical analysis, as well as a comparative experiment of thesingle-layer eight-bead deposition process show that the simulation results of the above two models agree with theexperimental results. At the same time, the proposed isosceles trapezoid-based overlappingmodels are all straightlineprofiles, which can be divided into high-quality FE elements. It can improve the modeling efficiency andshorten the simulation calculation time. The innovative modeling method proposed in this study can provide anefficient and high-precision geometricmodelingmethod forWAAMpart FE coupled thermal-mechanical analysis.

关键词： WAAM FE coupled thermal-mechanical analysis the isosceles trapezoid-based model residual stress

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EEG光子处理器——基于衍射光子计算单元的癫痫发作检测

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Engineering 2024年第4期35卷 56-66页

作者： Tao Yan Maoqi zhang Hang Chen Sen Wan Kaifeng Shang haiou zhang Xun Cao Xing Lin Qionghai Dai Department of Automation Tsinghua UniversityBeijing 100084China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Institute for Brain and Cognitive Sciences Tsinghua UniversityBeijing 100084China School of Electronic Science and Engineering Nanjing UniversityNanjing 210023China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Electroencephalography(EEG)analysis extracts critical information from brain signals,enabling brain disease diagnosis and providing fundamental support for brain–computer ***,performing an artificial intelligence analysis of EEG signals with high energy efficiency poses significant challenges for electronic processors on edge computing devices,especially with large neural network ***,we propose an EEG opto-processor based on diffractive photonic computing units(DPUs)to process extracranial and intracranial EEG signals effectively and to detect epileptic *** signals of the EEG channels within a second-time window are optically encoded as inputs to the constructed diffractive neural networks for classification,which monitors the brain state to identify symptoms of an epileptic *** developed both free-space and integrated DPUs as edge computing systems and demonstrated their applications for real-time epileptic seizure detection using benchmark datasets,that is,the Children’s Hospital Boston(CHB)–Massachusetts Institute of Technology(MIT)extracranial and Epilepsy-iEEG-Multicenter intracranial EEG datasets,with excellent computing performance *** with the channel selection mechanism,both numerical evaluations and experimental results validated the sufficiently high classification accuracies of the proposed opto-processors for supervising clinical *** study opens a new research direction for utilizing photonic computing techniques to process large-scale EEG signals and promote broader applications.

关键词： Epileptic seizure detection EEG analysis Diffractive photonic computing unit Photonic computing

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侧向轧制变胞机构的动力学仿真与优化设计

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华中科技大学学报（自然科学版） 2024年第6期52卷 56-62页

作者：孙乐乐张海鸥华中科技大学机械科学与工程学院湖北武汉430074

为了解决电弧增材制造存在变形及微观组织形态和力学性能较差的问题,采用轧制使材料的力学性能得到极大改善.为了合理设计轧制机构,针对一种侧向轧制变胞机构进行动力学分析和优化设计,分别分析了杆件尺寸、主动件速度、弹簧刚度在变胞... 详细信息

为了解决电弧增材制造存在变形及微观组织形态和力学性能较差的问题,采用轧制使材料的力学性能得到极大改善.为了合理设计轧制机构,针对一种侧向轧制变胞机构进行动力学分析和优化设计,分别分析了杆件尺寸、主动件速度、弹簧刚度在变胞机构运动过程中对变胞机构的影响.首先,分析了侧向轧制变胞机构的原理,得到了机构的基本结构;然后,选取合适的设计变量初始值与边界值,确定目标函数及约束条件;最后,在机械系统动力学自动分析(ADAMS)软件中建立机构的虚拟样机模型,在一定的侧向轧制力下,以主动件的驱动力最小为优化目标进行仿真求解,得到驱动力的最优解和相应设计变量的最优值.结果表明:最小驱动力较优化前减小了15.48%,主动件速度、杆件尺寸、弹簧刚度对变胞机构的影响程度是依次减弱的.

关键词：变胞机构电弧增材制造优化设计动态仿真机械系统动力学自动分析(ADAMS)

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电弧微铸锻复合增材制造GH4169D高温合金的显微组织与力学性能

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金属学报 2024年第5期60卷 681-690页

作者：曾立王桂兰张海鸥翟文正张勇张明波华中科技大学材料成形与模具技术国家重点实验室武汉430074 华中科技大学数字制造装备与技术国家重点实验室武汉430074 中国航发北京航空材料研究院北京100095

GH4169D合金作为一种新型的高力学性能和高稳定性的镍基高温合金,在用于制造高性能复杂结构零件方面具有巨大应用价值,但该合金在电弧增材制造中表现出柱状晶粗大、力学性能各向异性等问题。本工作采用电弧微铸锻复合增材制造(hybrid ar... 详细信息

GH4169D合金作为一种新型的高力学性能和高稳定性的镍基高温合金,在用于制造高性能复杂结构零件方面具有巨大应用价值,但该合金在电弧增材制造中表现出柱状晶粗大、力学性能各向异性等问题。本工作采用电弧微铸锻复合增材制造(hybrid arc and micro-rolling additive manufacturing,HARAM)技术成形GH4169D高温合金试块,并制定多种热处理制度对所成形的试块进行热处理。运用OM、SEM、EBSD、EDS、XRD、TEM等手段以及室温拉伸实验对合金的微观组织和力学性能进行观测和分析,并与常规电弧熔丝增材制造(wire and arc additive manufacturing,WAAM)方法成形的GH4169D合金进行对比。结果表明,HARAM技术中同步轧制的“微锻”作用能有效地使合金原本粗大的柱状晶发生“破碎”。与常规WAAM方法相比,采用HARAM技术所成形合金的室温抗拉强度提高(X向提高48 MPa,Z向提高90 MPa),力学性能的各向异性得到有效抑制。均匀化+固溶+双时效热处理有效消除了HARAM技术成形合金中的Laves偏析相,并促进受“微锻”作用的合金组织发生再结晶,使晶粒比未热处理时更为细小均匀,合金的综合力学性能达到最优(抗拉强度和断后延伸率X向为1366 MPa和25.0%,Z向为1354 MPa和24.6%)。

关键词：增材制造电弧微铸锻 GH4169D高温合金热处理显微组织力学性能

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百年旧体文学四人谈

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中国文学研究 2024年第1期 128-134页

作者：张海鸥张宁肖百容文浩湖南师范大学现代文学研究中心湖南长沙410081

文学研究作为对创作的回应和探索,离不开对宏观的历史大视野和整体的文化大视野的把握。回顾过去百年,旧体文学不论是作为文学现象还是作为文化现象,都无法让人忽视。各种旧体文学的创作、接受与批评样态及其与新文学乃至新文化的复杂纠... 详细信息

文学研究作为对创作的回应和探索,离不开对宏观的历史大视野和整体的文化大视野的把握。回顾过去百年,旧体文学不论是作为文学现象还是作为文化现象,都无法让人忽视。各种旧体文学的创作、接受与批评样态及其与新文学乃至新文化的复杂纠葛,也都是中国现当代文学史研究和中国现当代文学研究学术史难以绕开的话题。面对这样一座丰富的矿藏,我们必须深入开掘。对此问题,我们邀请到资深专家和学术新秀共同进行探讨。以后,我们还要邀请更多这方面的新老专家进行系列对谈,以期多维度透视百年旧体文学史的存在状态、发展流变和功能价值。

关键词：中国现当代文学史旧体文学中国现当代文学研究接受与批评大视野发展流变学术史新文学

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古诗词在台湾地区的演唱叙说——以“旧爱新欢——古诗词音乐创作”演唱为例

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中国韵文学刊 2024年第3期38卷 37-42页

作者：张海鸥李昱圻广州软件学院广东广州510900 南京大学文学院江苏南京210033

台湾汉光教育基金会举办“旧爱新欢——古诗词音乐创作征选”赛事已历十八届,演唱古代诗词,曲谱须为新创。参赛者不限身份地域,但既往十八届赛事参赛者主要是中国台湾年轻人,以高校学生为主,高校声乐专业师生很少参与。从历届状元、榜... 详细信息

台湾汉光教育基金会举办“旧爱新欢——古诗词音乐创作征选”赛事已历十八届,演唱古代诗词,曲谱须为新创。参赛者不限身份地域,但既往十八届赛事参赛者主要是中国台湾年轻人,以高校学生为主,高校声乐专业师生很少参与。从历届状元、榜眼、探花获奖作品可知,赛事组织者和参赛者对古诗词的选择与中国内地人基本一致,可见同源文化超时空审美之相似性。赛事表现出三个主要倾向:理解与共情、超时空联想、歌吟范式。

关键词：古诗词台湾地区演唱叙说

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A rapid forming method and simulation on controllable-porosity coating

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Science China(Technological Sciences) 2007年第6期50卷 786-796页

作者： zhang haiou HU BangYou WANG GuiLan School of Mechanical Science & Engineering Huazhong University of Science and Technology Wuhan 430074 China School of Mechanical Science & Engineering Huazhong University of Science and Technology Wuhan 430074 China School of Mechanical Science & Engineering Huazhong University of Science and Technology Wuhan 430074 China

A new method was introduced to fabricate porous coating and control its porosity by changing spray parameters. Two models were constructed to simulate the de- formation of droplet and the deposition process of splats on substrate. Considering the gap-pore, step-pore and shield-pore in the presented models, the influence of spray angle on the porosity of coating was mainly investigated. The simulation and experimental results show that the presented method is suitable for fabricating controllable-porosity coating. The porosity of coating can reach 49%. When the spray angle is lower than 30°, the porosity of coating rapidly increases because of shielding effect. Moreover, powder size and impact velocity also influence the po- rosity. Besides, a new forming method of graded porous coating was simulated by continuously changing the spray angle.

关键词： plasma spray, porosity, spray angle, porous material, functional gradient material

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电弧增材制造纳米TiC颗粒增强铝基复合材料组织与性能研究

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航空制造技术 2024年第10期67卷 115-121,130页

作者：吕奇钊周祥曼罗彬李波吴海华张海鸥三峡大学机械与动力学院宜昌443002 华中科技大学机械科学与工程学院武汉430074

在金属材料中引入第二相粒子是提高金属材料力学性能的重要手段之一。本文提出一种Al6061铝箔包裹TiC和Al6061的混合粉末形成一种特殊填料焊丝的TiC/Al6061复合材料电弧增材制造的新方法,并分别研究质量分数为1%、2%和3%的TiC颗粒对制... 详细信息

在金属材料中引入第二相粒子是提高金属材料力学性能的重要手段之一。本文提出一种Al6061铝箔包裹TiC和Al6061的混合粉末形成一种特殊填料焊丝的TiC/Al6061复合材料电弧增材制造的新方法,并分别研究质量分数为1%、2%和3%的TiC颗粒对制备的铝基复合材料组织与性能的影响。结果表明,TiC质量分数为3%的复合材料与基体材料相比,试样的平均晶粒尺寸由45.5μm减小到25.3μm,细化了44.4%;抗拉强度和屈服强度由148.5 MPa和118.0 MPa提升到178.1 MPa和157.3 MPa,分别提升了19.9%和33.3%;平均显微硬度由50.5HV增加至65.2HV,提升了29.1%。理论结合及试验分析表明,TiC的载荷传递强化和晶粒细化以及Orowan强化机制,是材料力学性能提高的主要原因。

关键词：电弧增材制造铝基复合材料(AMCs) TiC 微观组织力学性能

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Additive manufacturing of Ti-6Al-4V alloy by hybrid plasma-arc deposition and microrolling:Grain morphology,microstructure,and tensile properties

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Science China(Technological Sciences) 2022年第4期65卷 849-857页

作者： CHENG Kui zhang MingBo SONG Hao LIU XinWang FAN ZiTian WANG GuiLan zhang haiou State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

To address the problems of coarse columnar grains,inhomogeneous microstructure,and anisotropic mechanical properties of Ti-6Al-4V manufactured by wire and arc additive manufacturing(WAAM)and hybrid additive manufacturing with plasma-arc deposition,synchronous microrolling(HDMR)was examined in this *** leads to significant grain refinement and isotropy *** additive manufacturing alloys show typical columnar grains,while the microrolled ones show a transition from columnar to equiaxed grains with the fraction depending on the microrolling *** microrolling-induced formation of equiaxed grains is caused by both dendrite fragmentation and priorβrecrystallization in the subsequent ***,the rolling force required for good grain refinement in HDMR is much lower than that in WAAM with subsequent cold *** characteristics are present near the grain boundaries due to the recrystallizedαlamellae *** width of the basketweaveαlamellae decreases with the increasing microrolling *** yield strength and ultimate tensile strength of HDMR samples increase with a decrease in elongation *** study shows that HDMR can effectively refine grains and improve the tensile properties of titanium alloys,providing a broad prospect for the rapid formation of large titanium alloy parts.

关键词： titanium alloy additive manufacturing grain refinement microstructure tensile property

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