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Analog spatiotemporal feature extraction for cognitive radio-frequency sensing with integrated photonics

Light(Science & Applications) 2024年第3期13卷 478-487页

作者： Shaofu Xu Binshuo Liu Sicheng Yi Jing Wang Weiwen Zou State Key Laboratory of Advanced Optical Communication systems and Networks Intelligent Microwave Lightwave Integration Innovation Center(imLic)Department of Electronic EngineeringShanghai Jiao Tong UniversityShanghaiChina

Analog feature extraction(AFE)is an appealing strategy for low-latency and efficient cognitive sensing systems since key features are much sparser than the Nyquist-sampled ***,applying AFE to broadband radio-frequency(RF)scenarios is challenging due to the bandwidth and programmability bottlenecks of analog electronic ***,we introduce a photonics-based scheme that extracts spatiotemporal features from broadband RF signals in the analog *** feature extractor structure inspired by convolutional neural networks is implemented on integrated photonic circuits to process RF signals from multiple antennas,extracting valid features from both temporal and spatial *** of the tunability of the photonic devices,the photonic spatiotemporal feature extractor is trainable,which enhances the validity of the extracted ***,a digital-analog-hybrid transfer learning method is proposed for the effective and low-cost training of the photonic feature *** validate our scheme,we demonstrate a radar target recognition task with a 4-GHz instantaneous *** results indicate that the photonic analog feature extractor tackles broadband RF signals and reduces the sampling rate of analog-to-digital converters to 1/4 of the Nyquist sampling while maintaining a high target recognition accuracy of 97.5%.Our scheme offers a promising path for exploiting the AFE strategy in the realm of cognitive RF sensing,with the potential to contribute to the efficient signal processing involved in applications such as autonomous driving,robotics,and smart factories.

关键词： scheme driving smart

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Optical trapping capability of tornado circular Pearcey beams

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Chinese Physics B 2024年第5期33卷 401-407页

作者：刘娜娜唐晓莹刘舜禹梁毅 Guangxi Key Laboratory for Relativistic Astrophysics Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and Lifecycle Safety for Composite Structures Nanning 530004China

We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh *** tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pearcey beams with different *** theoretical exploration delves into various aspects,including the propagation dynamics,energy flux,orbital angular momentum,trapping force,and torque characteristics of *** results reveal that the orbital angular momentum,trapping force,and torque of these beams can be finely tuned through the judicious manipulation of their topological charges(l_(1)and l_(2)).Notably,we observe a precise control mechanism wherein the force diminishes with|l_(1)+l_(2)|and|l_(1)-l_(2)|,while the torque exhibits enhancement by decreasing solely with|l_(1)+l_(2)|or increasing with|l_(1)-l_(2)|.These results not only provide quantitative insights into the optical trapping performance of TCPBs but also serve as a valuable reference for the ongoing development of innovative photonic tools.

关键词： trapping capability tornado beams autofocusing

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Improvement in hydrogen storage performance of MgH_(2) by vanadium doped with ZIF-8 derived a single-atom catalyst V-N-C

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Rare Metals 2024年第6期43卷 2623-2635页

作者： Fei-Fan Hong Wei-Tao Shi Ruo-Lin Zhao Yi Fan Zi-Qi Liu Si-Zhi Ding Hai-Zhen Liu Wen-Zheng Zhou Jin Guo Zhi-Qiang Lan Guangxi Novel Battery Materials Research center of Engineering Technology and center on Nanoenergy Research Guangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationCarbon Peak and Neutrality Science and Technology Development InstituteSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China Nanning Engineering Technology Research center for Power Transmission System of New Energy Vehicle Transportation CollegeNanning UniversityNanning 530200China

Herein,the successful preparation of a singleatom catalyst V-N-C using vanadium-doped zeolitic imidazolate framework(ZIF)-8 as a precursor is *** experimental results showed that the V-N-C had a good promoting effect on the hydrogen storage performance of MgH_(2),and the optimal addition amount of V-N-C was 10wt%.The hydrogenation and dehydrogenation apparent activation energies of 10 wt%V-N-C-catalyzed MgH_(2)were reduced by 44.9 and 53.5 kJ·mol^(-1),respectively,compared to those of additive-free MgH_(2).The 10 wt%V-N-C-catalyzed MgH_(2)could reabsorb 5.92 wt%of hydrogen in 50 min at 150℃,with a capacity retention rate of 99.1%after 30 cycles of hydrogen absorption and *** analysis showed that V-N-C was partially transformed into VN and metallic V when it was milled with MgH_(2);the in-situ-formed VN and metallic V played an important role in improving the hydrogen storage performance of MgH_(2).This approach provides a potential solution for obtaining high-performance Mg-based hydrogen storage materials through synergistic interactions between V,N and C.

关键词： MgH_(2) Hydrogen storage materials Catalyst Hydrogen storage perormance

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A Review on the Security of the Ethereum-Based DeFi Ecosystem

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 69-101页

作者： Yue Xue Dunqiu Fan Shen Su Jialu Fu Ning Hu Wenmao Liu Zhihong Tian Cyberspace Institute of Advanced Technology Guangzhou UniversityGuanzhou510000China Innovation center NSFOCUS Inc.Beijing100089China Engineering Research center of integration and Application of Digital Learning Technology Ministry of EducationBeijing100816China

Decentralized finance(DeFi)is a general term for a series of financial products and *** is based on blockchain technology and has attracted people’s attention because of its open,transparent,and intermediary *** them,the DeFi ecosystem based on Ethereum-based blockchains attracts the most ***,the current decentralized financial system built on the Ethereum architecture has been exposed to many smart contract vulnerabilities during the last few ***,we believe it is time to improve the understanding of the prevailing Ethereum-based DeFi ecosystem security *** that end,we investigate the Ethereum-based DeFi security issues:1)inherited from the real-world financial system,which can be solved by macro-control;2)induced by the problems of blockchain architecture,which require a better blockchain platform;3)caused by DeFi invented applications,which should be focused on during the project *** on that,we further discuss the current solutions and potential directions ofDeFi *** to our research,we could provide a comprehensive vision to the research community for the improvement of Ethereum-basedDeFi ecosystem security.

关键词： Blockchain smart contract decentralized finance DeFi security

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Emerging materials and transistors for integrated circuits

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National Science Review 2024年第3期11卷 7-8页

作者： Ming Liu Lian-Mao Peng Lab of Nanofabrication and Novel Device integration Institute of Microelectronics Chinese Academy of Sciences Key Laboratory for the Physics and Chemistry of Nanodevices and center for Carbon-based Electronics School of Electronics Peking University

The device technology for integrated circuits(ICs) has received a great deal of attention in the past decade since the mainstream silicon-based complementary metal-oxide-semiconductor(CMOS) field-effect transistor(FET) for modern ICs had been encountering development bottlenecks due to the combination of power constraints, physics, cost and fabrication processes.

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Angular and planar transport properties of antiferromagnetic V5S8

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Chinese Physics B 2024年第2期33卷 83-88页

作者：吴晓凯王彬吴德桐陈博文弭孟娟王以林沈冰 center for Neutron Science and Technology and School of Physics Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devicesand Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-Sen University School of Integrated Circuits Shandong Technology Center of Nanodevices and Integration State Key Laboratory of Crystal MaterialsShandong University

Systemically angular and planar transport investigations are performed in layered antiferromagnetic(AF) V5S8. In this AF system, obvious anomalous Hall effect(AHE) is observed with a large Hall angle of 0.1 compared to that in ferromagnetic(FM) system. It can persist to the temperatures above AF transition and exhibit strong angular field *** phase diagram reveals various magnetic states by rotating the applied field. By analyzing the anisotropic transport behavior, magnon contributions are revealed and exhibit obvious angular dependence with a spin-flop vanishing line. The observed prominent planar Hall effect and anisotropic magnetoresisitivity exhibit two-fold systematical angular dependent oscillations. These behaviors are attributed to the scattering from spin–orbital coupling instead of nontrivial topological origin. Our results reveal anisotropic interactions of magnetism and electron in V5S8, suggesting potential opportunities for the AF spintronic sensor and devices.

关键词： antiferromagnetism planar Hall effect magnetic and topological properties

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Comparison of a Spectral Bin and Two Multi-Moment Bulk Microphysics Schemes for Supercell Simulation:Investigation into Key Processes Responsible for Hydrometeor Distributions and Precipitation

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Advances in Atmospheric Sciences 2024年第5期41卷 784-800页

作者： Marcus JOHNSON Ming XUE Youngsun JUNG center for Analysis and Prediction of Storms University of OklahomaNormanOK 73072USA School of Meteorology University of OklahomaNormanOK 73072USA Office of Science and Technology integration National Weather ServiceSilver SpringMD 20910USA

There are more uncertainties with ice hydrometeor representations and related processes than liquid hydrometeors within microphysics parameterization(MP)schemes because of their complicated geometries and physical *** supercell simulations are produced using the WRF model coupled with“full”Hebrew University spectral bin MP(HU-SBM),and NSSL and Thompson bulk MP(BMP)***-SBM downdrafts are typically weaker than those of the NSSL and Thompson simulations,accompanied by less rain ***-SBM produces more cloud ice(plates),graupel,and hail than the BMPs,yet precipitates less at the *** limiting mass bins(and subsequently,particle size)of rimed ice in HU-SBM and slower rimed ice fall speeds lead to smaller melting-level net rimed ice fluxes than those of the *** from plates in HU-SBM,together with snow–graupel collisions,leads to a greater snow contribution to rain than those of the *** HU-SBM’s fall speeds using the formulations of the BMPs after aggregating the discrete bin values to mass mixing ratios and total number concentrations increases net rain and rimed ice ***,they are smaller in magnitude than bulk rain,NSSL hail,and Thompson graupel net fluxes near the ***,the melting-layer net rimed ice fluxes are reduced when the fall speeds for the NSSL and Thompson simulations are calculated using HU-SBM fall speed formulations after discretizing the bulk particle size distributions(PSDs)into spectral *** results highlight precipitation sensitivity to storm dynamics,fall speed,hydrometeor evolution governed by process rates,and MP PSD design.

关键词： precipitation spectral bin microphysics bulk microphysics parameterization microphysics processes WRF model supercell storm

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State-sensitive convolutional sparse coding for potential biomarker identification in brain signals

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Science China(Information Sciences) 2024年第5期67卷 270-286页

作者： Puli WANG Yu QI Gang PAN College of Computer Science and Technology Zhejiang University State Key Laboratory of Brain-Machine Intelligence Zhejiang University MOE Frontier Science center for Brain Science and Brain-machine integration Zhejiang University Affiliated Mental Health center & Hangzhou Seventh People's Hospital Zhejiang University School of Medicine

The identification of prototypical waveforms, such as sleep spindles and epileptic spikes, is crucial for the diagnosis of neurological disorders. These prototypical waveforms are usually recurrently presented in certain brain states, serving as potential biomarkers for clinical evaluations. Convolutional sparse coding(CSC) approaches have demonstrated strength in identifying recurrent patterns in time-series. However,existing CSC approaches do not explicitly explore state-specific patterns, making it difficult to identify state-related biomarkers. To address this problem, we propose state-sensitive CSC to learn state-specific prototypical waveforms. Specifically, we model signals of a certain state with specific waveforms that only appear frequently in this state and background waveforms that are independent of states. Based on this,state-sensitive CSC separates state-specific waveforms from background ones explicitly by incorporating incoherence constraints into optimizations. Experiments with epilepsy brain signals demonstrate that our approach can effectively identify prototypical waveforms in pre-ictal states, providing potential biomarkers for seizure prediction. Our approach provides a promising tool for automatic biomarker candidate identification.

关键词： convolutional sparse coding prototypical waveforms state-specific dictionary biomarker identification neural signal processing

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A perspective on the key factors of safety for rechargeable magnesium batteries

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Journal of Energy Chemistry 2024年第7期94卷 656-676页

作者： Shuangshuang Tan Jie Xu Rongrui Deng Qiannan Zhao Chaohe Xu Guangsheng Huang Jingfeng Wang Fusheng Pan National Engineering Research center for Magnesium Alloys Chongqing UniversityChongqing 400044China National Innovation center for Industry-Education integration of Energy Storage Technology College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Chongqing Institute of New Energy Storage Materials and Equipment Chongqing 401135China

Rechargeable Mg batteries(RMBs)have become one of the best subsitutes for lithium-ion batteries due to the high volumetric capacity,abundant resources,and uniform plating behavior of Mg metal ***,the safety hazard induced by the formation of high-modulue Mg dendrites under a high current density(10 mA cm^(-1))was still revealed in recent *** has forced researchers to re-examine the safety of *** this review,the intrinsic safety factors of key components in RMBs,such as uneven plating,pitting and flammability of Mg anode,heat release and crystalline water decomposition of cathode,strong corrosion,low oxidition stability and flammability of electrolytes,and soforth,are systematacially *** origins,formation mechanisms,and possible safety hazards are deeply *** develop high-performance Mg anode,current strategies including designing artificial SEI,three-dimensional substrates,and Mg alloys are *** practical electrolytes,the configurations of boron-centered anions and simple Mg salts and the functionalized solvent with high boiling point and low flammability are suggested to comprehensively *** addition,the future study should more focus on the investigation on the thermal runaway and decomposition of cathode materials and *** review aims to provide fundamental insights into the relationship between electrochemistry and safety,further promoting the sustainable development of RMBs.

关键词： Rechargeable Mg batteries Battery safety Mg dendrites Electrolyte decomposition Intrinsic safety issues

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Combinations of electron and proton donors in transition-metal complex mediated nitrogen reduction reactions

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Science China Chemistry 2024年第7期67卷 2136-2154页

作者： Delong Han Li Yang Hao Huang Priyanka Chakraborty Shashikant U.Dighe Kuo-Wei Huang KAUST Catalysis center and Division of Physical Science and Engineering King Abdullah University of Science and TechnologyThuwal 23955Saudi Arabia Agency for Science Technologyand ResearchInstitute of Materials Research and Engineering and Institute of Sustainability for ChemicalsEnergy and EnvironmentSingapore 138634Singapore

Nitrogen fixation is a complex process involving the transfer of six electrons and *** from the conventional Haber-Bosch process,which relies on hydrogen(H_(2))to provide both electrons and protons to reduce nitrogen(N_(2)),homogeneous transition metal complex-catalyzed N_(2)reduction reactions(NRR)employ an array of electron and proton donors or even electron donors combined with *** the synthesis of diverse catalytic progress,the categories of donors have seen rapid ***,existing literature only provides summaries regarding the metal,ligands,and *** the significance of electron and proton donor combinations in nitrogen reduction reactions,no literature has thoroughly reviewed this ***,we hereby compiled a comprehensive list of commonly used reagents in N_(2)reduction and classified them according to their specific donor *** review presents clear and organized information about these combinations,along with a summary of their general performance trend in NRR with related ***,we conclude the discussion by highlighting key points for researchers to consider when selecting catalysts and donor combinations,with the ultimate goal of advancing the field of nitrogen fixation.

关键词： dinitrogen reduction reaction reducing donor combination transition metal complexes homogeneous catalysis

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