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Surface morphologies of Mg-Gd alloy particle during its reactions with O_(2) and Teflon

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Defence Technology（防务技术） 2024年第3期33卷 209-221页

作者： yifan li Hongtao Yang Aifeng Jiang Dongming Song Yanchun li Department of Chemical Engineering Nanjing University of Science and TechnologyNanjing 210097China Xi'an Modern Chemistry Research Institute Xi'an 710065China Southwest Technology and Engineering Research Institute Chongqing 400039China

Mg-Gd alloy particle has exhibited its unique combustion properties as the fuel of Mg/Teflon/Viton(MTV).Mg-Gd alloy/Teflon/Viton(MGTV)could burn at lower ambient pressure than *** further investigate the reaction of MGTV in air,it was investigated via thermo gravity-differential scanning calorimetry(TG-DSC).Meanwhile,the morphologies and element distributions on the alloy surface during the reaction of MGTV in air were investigated via scanning electronic microscope-mapping-electronic differential ***,a similar experimental protocol on the Mg-Gd alloy particle during oxidation was also *** results showed that owning to a protective oxide shell,the onset oxidation temperature of Mg-Gd alloy is higher than ***,the onset oxidation temperature of the exceeded Mg-Gd alloy in MGTV is significantly lower than that of the exceeded Mg in *** was due to the existence of GdOF,which could significantly lower the oxidation temperature of the exceeded ***,a possible reaction mechanism was *** fascinating oxidation properties of Mg-Gd alloy suggested its promising applications in energetic materials.

关键词： Mg-Gd alloy Energetic materials Morphology EDS GdOF

Automated identification of steel weld defects,a convolutional neural network improved machine learning approach

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 294-308页

作者： Zhan SHU Ao WU Yuning SI Hanlin DONG Dejiang WANG yifan li School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China School of Civil Engineering Shanghai Normal UniversityShanghai 201418China Shanghai PinlanData Technology Co. Ltd.Shanghai 200072China

This paper proposes a machine-learning-based methodology to automatically classify different types of steel weld defects,including lack of the fusion,porosity,slag inclusion,and the qualified(no defects)*** methodology solves the shortcomings of existing detection methods,such as expensive equipment,complicated operation and inability to detect internal *** study first collected percussed data from welded steel members with or without weld ***,three methods,the Mel frequency cepstral coefficients,short-time Fourier transform(STFT),and continuous wavelet transform were implemented and compared to explore the most appropriate features for classification of weld *** and convolutional neural network-enhanced algorithms were used to classify,the extracted ***,experiments were designed and performed to validate the proposed *** showed that STFT achieved higher accuracies(up to 96.63%on average)in the weld status *** convolutional neural network-enhanced support vector machine(SVM)outperformed six other algorithms with an average accuracy of 95.8%.In addition,random forest and SVM were efficient approaches with a balanced trade-off between the accuracies and the computational efforts.

关键词： steel weld machine learning convolutional neural network weld defect detection classification task percussion

A Fast Startup Crystal Oscillator with Digital SAR-AFC Based Two-Step Injection

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Chinese Journal of Electronics 2024年

作者： Bo ZHOU yifan li Zuhang WANG School of Integrated Circuits and Electronics Beijing Institute of Technology

Crystal oscillators（XOs） provide a high-precision reference frequency but have a long startup time,which severely increases the average power consumption in duty-cycled systems. This paper proposes a fully-digital low-cost two-step injection（TSI） technique, by using a successive approximation register（SAR） based auto frequency control（AFC） loop, to speed up the startup behavior of XOs. A theoretical analysis is carried out to determine the optimum injection time and design low-power XOs. Fabricated in a 65 nm CMOS process, the proposed 12 MHz fast startup XO occupies an active area of 0.02 mm2and achieves a startup time less than 35 μs. The XO power consumption in the steady state is 40 μW from a 1.0-V supply, with a startup energy of 17.2 nJ.

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In-doping collaboratively controlling back interface and bulk defects to achieve efficient flexible CZTSSe solar cells

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Journal of Energy Chemistry 2024年第2期89卷 10-17,I0002页

作者： Quanzhen Sun yifan li Caixia Zhang Shunli Du Weihao Xie Jionghua Wu Qiao Zheng Hui Deng Shuying Cheng Institute of Micro-Nano Devices and Solar Cells College of Physics and Information EngineeringFuzhou UniversityFuzhou 350108FujianChina Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108FujianChina Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering Changzhou 213164JiangsuChina

Focusing on the low open circuit voltage(V_(OC))and fill factor(FF)in flexible Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)solar cells,indium(In)ions are introduced into the CZTSSe absorbers near Mo foils to modify the back interface and passivate deep level defects in CZTSSe bulk concurrently for improving the performance of flexible *** results show that In doping effectively inhibits the formation of secondary phase(Cu(S,Se)_(2))and *** studies demonstrate that the barrier height at the back interface is decreased and the deep level defects(Cu_(Sn)defects)in CZTSSe bulk are ***,the carrier concentration is increased and the V_(OC) deficit(V_(OC,def))is decreased significantly due to In ***,the flexible CZTSSe solar cell with 10.01%power conversion efficiency(PCE)has been *** synergistic strategy of interface modification and bulk defects passivation through In incorporation provides a new thought for the fabrication of efficient flexible kesterite-based solar cells.

关键词： Flexible solar cells Cu_(2)ZnSn(S,Se)_(4) Back interface Deep level defects Barrier height

Rapid Phase Ambiguity Elimination Methods for DOA Estimator via Hybrid Massive MIMO Receive Array

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Chinese Journal of Electronics 2024年第1期33卷 175-184页

作者： Xichao ZHAN Zhongwen SUN Feng SHU Yiwen CHEN Xin CHENG Yuanyuan WU Qi ZHANG yifan li Peng ZHANG School of Information and Communication Engineering Hainan University School of Electronic and Optical Engineering Nanjing University of Science and Technology

For a sub-connected hybrid multiple-input multiple-output(MIMO) receiver with K subarrays and N antennas, there exists a challenging problem of how to rapidly remove phase ambiguity in only single time-slot. A direction of arrival(DOA) estimator of maximizing received power(Max-RP) is proposed to find the maximum value of K-subarray output powers, where each subarray is in charge of one sector, and the center angle of the sector corresponding to the maximum output is the estimated true DOA. To make an enhancement on precision, Max-RP plus quadratic interpolation(Max-RP-QI) method is designed. In the proposed Max-RP-QI, a quadratic interpolation scheme is adopted to interpolate the three DOA values corresponding to the largest three receive powers of *** achieve the Cramer Rao lower bound, a Root-MUSIC plus Max-RP-QI scheme is developed. Simulation results show that the proposed three methods eliminate the phase ambiguity during one time-slot and also show low computational complexities. The proposed Root-MUSIC plus Max-RP-QI scheme can reach the Cramer Rao lower bound,and the proposed Max-RP and Max-RP-QI are still some performance losses 2–4 d B compared to the Cramer Rao lower bound.

关键词： Phased arrays Interpolation Wireless sensor networks Direction-of-arrival estimation Simulation Receiving antennas Massive MIMO

Exploring the role of iron in Fe_(5)Ni_(4)S_(8)toward oxygen evolution through modulation of electronic orbital occupancy

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Journal of Energy Chemistry 2024年第5期92卷 52-62页

作者： Zhengyan Du Zeshuo Meng Haoteng Sun yifan li Chao Jiang Yaxin li Xiaoying Hu Yi Cui Shansheng Yu Hongwei Tian Key Laboratory of Automobile Materials of MOE School of Materials Science and EngineeringJilin UniversityChangchun 130012JilinChina College of Science and Laboratory of Materials Design and Quantum Simulation Changchun UniversityChangchun 130022JilinChina i-lab Vacuum Interconnected Nanotech Workstation(Nano-X)Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123JiangsuChina Department of Chemistry Brown UniversityRI 02912United States

Ni-Fe-based catalysts are considered to be among the most active catalysts for the oxygen evolution reaction(OER)under alkaline conditions,with Fe playing a crucial ***,Fe leaching occurs during the reaction due to thermodynamic instability,which has resulted in conflicting reports within the literature regarding its *** clarify this point,we propose a strategy consisting of modulating the electronic orbital occupancy to suppress the extensive loss of Fe atoms during the OER *** calculations,in-situ X-ray photoelectron spectroscopy,molecular dynamics simulations,and a series of characterization showed that the stable presence of Fe not only accelerates the electron transfer process but also optimizes the reaction barriers of the oxygen evolution intermediates,promoting the phase transition of Fe_(5)Ni_(4)S_(8)to highly active catalytic *** modulated Fe_(5)Ni_(4)S_(8)-based pre-catalysts exhibit improved OER activity and long-term *** study provides a novel perspective for understanding the role of Fe in the OER process.

关键词： Oxygenevolution Fe_(5)Ni_(4)S_(8) Electronic orbital occupancy modulation Reconstruction dynamics

The Roadmap of 2D Materials and Devices Toward Chips

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Nano-Micro Letters 2024年第6期16卷 343-438页

作者： Anhan liu Xiaowei Zhang Ziyu liu Yuning li Xueyang Peng Xin li Yue Qin Chen Hu Yanqing Qiu Han Jiang Yang Wang yifan li Jun Tang Jun liu Hao Guo Tao Deng Songang Peng He Tian Tian‑ling Ren School of Integrated Circuits and Beijing National Research Center for Information Science and Technology(BNRist) Tsinghua UniversityBeijing 100049People’s Republic of China School of Microelectronics Fudan UniversityShanghai 200433People’s Republic of China State Key Laboratory of Dynamic Measurement Technology Shanxi Province Key Laboratory of Quantum Sensing and Precision MeasurementNorth University of ChinaTaiyuan 030051People’s Republic of China High‑Frequency High‑Voltage Device and Integrated Circuits R&D Center Institute of MicroelectronicsChinese Academy of SciencesBeijing 100029People’s Republic of China School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044People’s Republic of China School of Integrated Circuits University of Chinese Academy of SciencesBeijing 100049People’s Republic of China IMECAS-HKUST-Joint Laboratory of Microelectronics Beijing 100029People’s Republic of China

Due to the constraints imposed by physical effects and performance degra certain limitations in sustaining the advancement of Moore’s ***-dimensional(2D)materials have emerged as highly promising candidates for the post-Moore era,offering significant potential in domains such as integrated circuits and next-generation ***,in this review,the progress of 2D semiconductors in process engineering and various electronic applications are summarized.A careful introduction of material synthesis,transistor engineering focused on device configuration,dielectric engineering,contact engineering,and material integration are given *** 2D transistors for certain electronic applications including digital and analog circuits,heterogeneous integration chips,and sensing circuits are ***,several promising applications(artificial intelligence chips and quantum chips)based on specific mechanism devices are ***,the challenges for 2D materials encountered in achieving circuit-level or system-level applications are analyzed,and potential development pathways or roadmaps are further speculated and outlooked.

关键词： Two-dimensional materials Roadmap Integrated circuits Post-Moore era

Mechanically strong porous bioceramic tubes facilitate large segmental bone defect repair by providing long-term structurally stability and promoting osteogenesis

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Engineered Regeneration 2024年第1期5卷 1-10页

作者： lijun Xie Jiahao Zhang Hangxiang Sun Zehao Chen Wangsiyuan Teng Xupeng Chai Cong Wang Xianyan Yang yifan li Sanzhong Xu Zhongru Gou Zhaoming Ye Department of Orthopedic Surgery the Second Affiliated HospitalZhejiang University School of MedicineHangzhou 310000PR China Orthopedics Research Institute of Zhejiang University Hangzhou 310000PR China Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejiang Province Hangzhou 310000PR China Bio-nanomaterials and Regenerative Medicine Research Division Zhejiang-California International Nanosystem InstituteZhejiang UniversityHangzhou 310058PR China Department of Orthopedics the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003PR China

Mechanically strong magnesium-doped Ca-silicate bioceramic scaffolds have many advantages in repairing large segmental bone *** we combine β-TCP with 6 mol%magnesium-doped calcium silicate(Mg6)at three different ratios(TCP,TCP+15%Mg6,TCP+85%Mg6)to find an appropriate ratio which can exert considerable influence on bone *** this study,the bioceramic scaffolds were assessed for mechanical strength,bioactive ion release,biocompatibility,and osteogenic capacity through in vitro ***,the potential for promoting bone regeneration was investigated through in vivo implantation of porous tube-like *** results showed that the compressive strength increased with the augmentation of Mg6 *** the compressive strength of the TCP+85%Mg6 group reached 38.1±3.8 MPa,three times that of the other two ***,extensive in vivo investigations revealed that the TCP+85%Mg6 bioceramic scaffolds were particularly beneficial for the osteogenic capacity of critical-sized femoral defects(20 mm in length).Altogether,magnesium doping in bioceramic implants is a promising strategy to provide stronger mechanical support and enhance osteogenesis to accelerate the repair of large defects.

关键词： Bioceramic tubes Mg-doped calcium silicate Porous structural stability Large segmental bone defects Digital light processing

Unveiling the secrets of diatom-mediated calcification: Implications for the biological pump

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Science China Earth Sciences 2024年第9期67卷 2895-2909页

作者： Yiwen PAN yifan li Chen-Tung Arthur CHEN Zong-Pei JIANG Wei-Jun CAI Yunwen SHEN Zesheng DING Qixian CHEN Yanan DI Wei FAN Chenba ZHU Ying CHEN Ocean College Zhejiang University Hainan Institute of Zhejiang University Department of Oceanography Sun Yat-Sen University School of Marine Science and Policy University of Delaware Carbon Neutral Innovation Research Center Xiamen University

Siliceous diatoms are one of the most prominent actors in the oceans, and they account for approximately 40% of the primary production and particulate organic carbon export flux. It is believed that changes in carbon flux caused by variations in diatom distribution can lead to significant climate shifts. Although the fundamental pathways of diatom-driven carbon sequestration have long been established, there are no reports of CaCO3precipitation induced by marine diatom species. This manuscript introduces novel details regarding the enhancement of aragonite precipitation during photosynthesis in Skeletonema costatum in both artificial and natural seawater. Through direct measurements of cell surfaces via a pH microelectrode and zeta potential analyzer, it was determined that the diatom-mediated promotion of CaCO3precipitation is achieved through the creation of specific microenvironments with concentrated [CO32–] and [Ca2+] and/or the dehydrating effect of adsorbed Ca2+.Based on this mechanism, it is highly plausible that diatom-mediated calcification could occur in the oceans, an assertion that was supported by the significant deviation of total alkalinity（TA） from the conservative TA-salinity mixing line during a Skeletonema costatum bloom in the East China Sea and other similar occurrences. The newly discovered calcification pathway establishes a link between particulate inorganic and organic carbon flux and thus helps in the reassessment of marine carbon export fluxes and CO2sequestration efficiency. This discovery may have important ramifications for assessing marine carbon cycling and predicting the potential effects of future ocean acidification.

关键词： Diatom bloom Skeletonema costatum Calcification Biological carbon pump Counter carbonate pump

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