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A real-time calibration method based on time-to-digital converter for accelerator timing system

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Nuclear Science and Techniques 2024年第9期 186-199页

作者： qi-hao duan Liang Ge Yan-hao Jia Jie-Yu Zhu Wei Zhang Institute of modern physics Chinese Academy of Sciences University of Chinese Academy of Sciences

The high-intensity heavy-ion accelerator facility(HIAF) is a scientific research facility complex composed of multiple cascade accelerators of different types, which pose a scheduling problem for devices distributed over a certain range of 2 km,involving over a hundred devices. The white rabbit, a technology-enhancing Gigabit Ethernet, has shown the capability of scheduling distributed timing devices but still faces the challenge of obtaining real-time synchronization calibration parameters with high precision. This study presents a calibration system based on a time-to-digital converter implemented on an ARM-based System-on-Chip(SoC). The system consists of four multi-sample delay lines, a bubble-proof encoder, an edge controller for managing data from different channels, and a highly effective calibration module that benefits from the SoC architecture. The performance was evaluated with an average RMS precision of 5.51 ps by measuring the time intervals from 0 to 24,000 ps with 120,000 data for every test. The design presented in this study refines the calibration precision of the HIAF timing system. This eliminates the errors caused by manual calibration without efficiency loss and provides data support for fault diagnosis. It can also be easily tailored or ported to other devices for specific applications and provides more space for developing timing systems for particle accelerators, such as white rabbits on HIAF.

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Accurate Distinction of Weak and Strong AC Grids for Emerging Hierarchical-Infeed LCC-UHVDC Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 772-777页

作者： hao Xiao Xianzhong duan Yi Zhang Department of Electrical and Computer Engineering University of ManitobaWinnipeg R3T 2N2ManitobaCanada State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Electric Power Security and High Efficiency Key LaboratorySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina RTDS Technologies Inc. Winnipeg R3T 2E1ManitobaCanada

Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were developed by empirical reasoning without rigorous theoretical analysis. Hence in this letter, hierarchical-infeed interactive effective short-circuit ratio (HIESCR) index is first used for strength evaluation of HIDC systems with complex inter-inverter interactions considered. Boundary HIESCR (BHIESCR) is also introduced in the proposed distinction method of weak and strong AC grids. That is, weak (or strong) AC grids are, respectively, identified when HIESCR is less (or greater) than BHIESCR. Second, it is shown BHIESCR remains almost unchanged as 3.0 versus various system parameters and rated operation variables based on rigorous theoretical analysis. This salient feature makes the proposed method more accurate than earlier methods. Finally, the proposed method is validated by simulations based on the PSCAD/EMTDC program.

关键词： Hierarchical-Infeedinteractive effective short-circuit ratio hierarchical-infeed LCC-UHVDC systems inter-inverter interactions strong AC grids weak AC grids

P-symmetric Subharmonic Solutions for Nonlinear Hamiltonian Systems

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1388-1408页

作者： duan Zhi ZHANG Zhi hao Zhao School of Mathematical Sciences Nankai UniversityTianjin 300071P.R.China

In this paper,we prove that for each positive k≡1 mod m there exists a P-symmetric kmτ-periodic solution xk for asymptotically linear mτ-periodic Hamiltonian systems,which are nonautonomous and endowed with a *** the P-symmetric Hamiltonian function is semi-positive,one can prove,under a new iteration inequality of the Maslov-type P-index,that xk_(1) and xk_(2) are geometrically distinct for k_(1)/k_(2)≥(2n+1)m+1;and xk_(1),xk_(2) are geometrically distinct for k_(1)/k_(2)≥m+1 provided xk_(1) is non-degenerate.

关键词： P-symmetric subharmonic Hamiltonian systems Maslov-type index theory iteration inequality asymptotically linear

Design, modeling, and evaluation of parallel continuum robots: A survey

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Science China(Technological Sciences) 2024年第3期67卷 673-695页

作者： CHEN GenLiang TANG ShuJie duan XuYang WANG hao Meta Robotics Institute Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Mechanical Systems and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of Digital Manufacturing for Thin-Walled Structures Shanghai Jiao Tong UniversityShanghai 200240China

Parallel continuum robots(PCRs) have attracted increasing attention in the robotics community due to their simplicity in structure,inherence with compliance, and easiness of realization. Over the past decade, a variety of novel designs have been reported to enrich their diversity. However, there is a lack of systematic review of these emerging robots. To this end, this paper conducts a comprehensive survey on the mechanism design, kinetostatic modeling and analysis, and performance evaluation. For these robots, kinetostatic modeling plays a fundamental role throughout the design, analysis, and control stages. A systematic review of the existing approaches for kinetostatic modeling and analysis is provided, and a comparison is made to distinguish their differences. As well, a classification is made according to the characteristics of structure and actuation. In addition, performance evaluation on the workspace, stability, and singularity is also overviewed. Finally, the scenarios of potential applications are elaborated, and future research prospects are discussed. We believe that the information provided in this paper will be particularly useful for those who are interested in PCRs.

关键词： parallel continuum robots classification kinetostatic modeling performance evaluation

PEGA:probabilistic environmental gradient-driven genetic algorithm considering epigenetic traits to balance global and local optimizations

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Frontiers of Information Technology & Electronic Engineering 2024年第6期25卷 839-855页

作者： Zhiyu duan Shunkun YANG qi Shao Minghao YANG School of Reliability and Systems Engineering Beihang UniversityBeijing 100191China

Epigenetics’flexibility in terms of finer manipulation of genes renders unprecedented levels of refined and diverse evolutionary mechanisms *** the epigenetic perspective,the main limitations to improving the stability and accuracy of genetic algorithms are as follows:(1)the unchangeable nature of the external environment,which leads to excessive disorders in the changed phenotype after mutation and crossover;(2)the premature convergence due to the limited types of epigenetic *** this paper,a probabilistic environmental gradientdriven genetic algorithm(PEGA)considering epigenetic traits is *** enhance the local convergence efficiency and acquire stable local search,a probabilistic environmental gradient(PEG)descent strategy together with a multi-dimensional heterogeneous exponential environmental vector tendentiously generates more offsprings along the gradient in the solution ***,to balance exploration and exploitation at different evolutionary stages,a variable nucleosome reorganization(VNR)operator is realized by dynamically adjusting the number of genes involved in mutation and *** on the above-mentioned operators,three epigenetic operators are further introduced to weaken the possible premature problem by enriching genetic *** experimental results on the open Congress on Evolutionary Computation-2017(CEC’17)benchmark over 10-,30-,50-,and 100-dimensional tests indicate that the proposed method outperforms 10 state-of-the-art evolutionary and swarm algorithms in terms of accuracy and stability on comprehensive *** ablation analysis demonstrates that for accuracy and stability,the fusion strategy of PEG and VNR are effective on 96.55%of the test functions and can improve the indicators by up to four orders of ***,the performance of PEGA on the real-world spacecraft trajectory optimization problem is the best in terms of quality of the solution.

关键词： Evolutionary algorithm Epigenetics Epigenetic algorithm Probabilistic environmental vector Variable nucleosome reorganization

A new liquid membrane diffusion model for characterizing the adsorption kinetics of europium by using a continuous measurement of adsorption platform

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Nuclear Science and Techniques 2024年第1期35卷 59-72页

作者： hao-qi Yu Tao Yu Jian-Hua Ye State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China CGN Cangnan Nuclear Power Co. Ltd.Cangnan 325800China Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices East China University of TechnologyNanchang 330013China School of Nuclear Science and Engineering East China University of TechnologyNanchang 330013China

To explore the kinetic adsorption under continuous and nonequilibrium states, an integration of continuous measurement and adsorption platform kinetics method was proposed, which was initially called the ICM-AP kinetics method, and a corresponding kinetic adsorption experimental method was developed. Adsorption experiments of europium(Eu) on Ca-bentonite,Na-bentonite, and the D231 cation exchange resin were performed using the ICM-AP kinetics method and continuous measurements. Because the kinetic experimental results observed in this study were different from those of traditional batch adsorption data, pseudo-first-order or pseudo-second-order kinetic models were unsuitable for fitting the experimental ***, a liquid membrane diffusion(LMD) model was developed based on the assumption of simultaneous adsorption/desorption to discuss the mechanism of kinetic adsorption. The kinetic adsorption mechanism was also studied by using *** results indicated that the proposed adsorption model can fit the experimental data more suitably, and the adsorption/desorption behaviors of Eu on bentonite and the D231 resin were simultaneously observed, suggesting that the adsorption kinetics of Eu(Ⅲ) was mainly dominated by hydrated Eu(Ⅲ) ions on the liquid membrane.

关键词： ICM-AP method LMD model Adsorption mechanism Eu(Ⅲ)

MXene-derived quantum dots based photocatalysts:Synthesis,application,prospects,and challenges

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Chinese Chemical Letters 2024年第6期35卷 123-133页

作者： hao Deng Yuxin Hui Chao Zhang qi Zhou qiang Li hao Du Derek hao Guoxiang Yang qi Wang School of Environmental Science and Engineering Zhejiang Gongshang UniversityHangzhou 310018China Instrumental Analysis Center of Zhejiang Gongshang University Hangzhou 310018China Centre for Technology in Water and Wastewater(CTWW) School of Civil and Environmental EngineeringUniversity of Technology Sydney(UTS)UltimoNSW 2007Australia

In recent years,the emerging two-dimensional material-MXenes has attracted widespread attention in the field of photocatalysis due to its high conductivity,suitable Fermi level,tunable elemental composition,and excellent photoelectric *** zero-dimensional quantum dots(MQDs)derived from 2D MXenes not only inherit the characteristics of MXenes but also exhibit better performance due to the quantum size *** on the above excellent physical and chemical properties,MQDs are often used as co-catalysts of photocatalysts,and show excellent co-catalytic *** the same time,compared with other cocatalysts(precious metals,metal oxides,metal sulfides),it has the advantages of low cost and high ***,understanding the status of MQDs in the field of photocatalysis is crucial for their further *** this review,we summarized the synthesis and modification methods of MQDs in recent years,as well as their photocatalytic applications in H_(2) production,CO_(2) reduction,N_(2) fixation,pollutant degradation,and other *** addition,the challenges and prospects faced by MQDs are also proposed,providing theoretical guidance for the further development of MQD-based photocatalysts.

关键词： MXenes Quantum dots Photocatalysis Composites Environment purification

High-entropy materials:Excellent energy-storage and conversion materials in the field of electrochemistry

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Particuology 2024年第9期92卷 42-60页

作者： Jincan Li Huiyu duan qi Long Bianjiang Zhang Changyun Chen Huan Pang Key Laboratory of Advanced Functional Materials of Nanjing School of Environmental ScienceNanjing Xiaozhuang UniversityNanjing211171China School of Chemical Engineering Institute for Innovative Materials and EnergyYangzhou UniversityYangzhou225009China

High-entropy materials(HEMs),a new type of materials,have attracted significant attention in the field of electrocatalytic reactions,batteries and energy-storage materials over the past few years owing to their unique structure,controllable elementary composition,and adjustable *** excellent characteristics result from four major factors:high entropy,sluggish-diffusion,severe lattice distortion,and cocktail effect,and are used widely in energy-energy *** review aims to summarize the recent progress of HEMs in electrochemical *** begin with the concept,structure,and four core effects of HEMs that provide the basic information on ***,we discuss the major properties of HEMs and analyze the relationship between their structures and ***,we highlight the outstanding performance of HEMs in hydrogen storage,electrode materials of batteries,catalysis,and supercapacitors,and briefly explain the mechanisms of these materials that are crucial in energy storage and *** review will assist in understanding the excellent energy-storage properties,intricacies of the phase structures,elemental interactions,and reaction mechanisms associated with ***,challenges and future development prospects are *** work will provide insight into the factors that are crucial for designing HEMs with energy storage properties.

关键词： High-entropy materials Hydrogen storage Electrode materials of batteries Catalyst Supercapacitor

A High-Performance MoS_(2)-Based Visible-Near-Infrared Photodetector from Gateless Photogating Effect Induced by Nickel Nanoparticles

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Research 2024年第2期6卷 171-179页

作者： Ran duan Weihong qi Panke Li Kewei Tang Guoliang Ru Weimin Liu State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 265503China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Recent advancements in two-dimensional materials have shown huge potential for optoelectronic *** is challenging to achieve highly effective and sensitive broadband photodetection based on MoS_(2)*** engineering,such as introducing vacancies,can narrow the bandgap and boost the separation of photogenerated carriers by defect states but leads to a slow response ***,we propose a nickel nanoparticle-induced gateless photogating effect with a unique energy band structure to enable the application of defect engineering and achieve high optoelectronic *** device based on Ni nanoparticle-decorated MoS_(2)with S vacancies exhibited high responsivities of 106.21 and 1.38 A W^(-1)and detectivities of 1.9×10^(12)and 8.9×10^(9)Jones under 532 and 980 nm illumination(visible to near infrared),respectively,with highly accelerated response *** strategy provides new insight into optimizing defect engineering to design high-performance optoelectronic devices capable of broadband photodetection.

关键词： defect Infrared illumination