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Beam position monitors as precise phase pickups for beam energy measurement at the Compact Pulsed Hadron Source

Nuclear Science and Techniques 2019年第2期30卷 1-9页

作者： Min-Wen Wang Qing-Zi Xing Shu-Xin Zheng Zhong-Ming Wang Meng-Tong Qiu Xia-Ling Guan Xue-Wu Wang Wen-Hui Huang Laboratory of Particle and Radiation Imaging Ministry of EducationTsinghua University Laboratory for Advanced Radiation Sources and Application Tsinghua University Department of Engineering Physics Tsinghua University State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology

The 13-MeV proton linac of the Compact Pulsed Hadron Source(CPHS) at Tsinghua University, China,is composed of a 50-keV electron cyclotron resonance proton source, a 3-MeV four-vane-type radio-frequency quadrupole(RFQ) accelerator, and a drift tube linac(DTL). Precise measurement of the beam energies at the exit of the RFQ and the DTL is critical for DTL commissioning. Two button-type beam position monitors(BPMs) installed downstream of the RFQ are used to perform the measurement using a time-of-flight method. The effects of several factors on phase measurement accuracy are analyzed. The phase measurement accuracy of the BPMs at CPHS is better than ± 1.03° at 325 MHz after corrections,corresponding to an energy measurement error of± 0.07%. The beam energy measured at the exit of the RFQ is 2.994 ± 0.0022 MeV,which is consistent with the design value.

关键词： Beam energy Time of flight Beam position monitor Phase pickup

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Evaluating rainfall erosivity on the Tibetan Plateau by integrating high spatiotemporal resolution gridded precipitation and gauge data

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Science of the Total Environment 2024年 947卷 174334页

作者： Yin, Bing Xie, Yun Yao, Chong Liu, Bing Liu, Baoyuan School of Soil and Water Conservation Nanchang Institute of Technology Nanchang330099 China Institute of Soil and Water Conservation Northwest A&F University Shaanxi Yangling712100 China Department of Geographic Science Faculty of Arts and Sciences Beijing Normal University at Zhuhai Zhuhai519087 China College of geographical sciences Xinyang Normal University Henan Xinyang464000 China State Key Lab of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing100048 China Advanced Institute of Natural Sciences State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University at Zhuhai Zhuhai519087 China

High-precision rainfall erosivity mapping is crucial for accurately evaluating regional soil erosion on the Tibetan Plateau (TP) under the backdrop of climate warming and humidification. Although high spatiotemporal resolution gridded precipitation data provides the foundation for rainfall erosivity mapping, the increasing spatial heterogeneity of rainfall with decreasing temporal granularity can lead to greater errors when directly computing rainfall erosivity from gridded precipitation data. In this study, a site-scale conversion coefficient was established so that rainfall erosivity calculated using hourly data can be converted to rainfall erosivity calculated using per-minute data. A revised model was established for calculating the rainfall erosivity based on high-resolution hourly precipitation data from the Third Pole gridded precipitation dataset (TPHiPr). The results revealed a notable underestimation in the original calculation results obtained using the TPHiPr, but strong correlation was observed between the two sets of results. There was a significant improvement in the Nash–Sutcliffe coefficient of efficiency (from −0.39 to 0.80) and the Percent Bias (from −63.95 % to 0.37 %) after model revision. The TPHiPr effectively depict the spatial characteristics of rainfall erosivity on the TP. It accurately reflected the rain shadow area on the northern flank of the Himalayas and the dry-hot valley in the Hengduan Mountains. It also showed high rainfall erosivity values in the tropical rainforest area on the southern flank of the eastern Himalayas. The overall trend of rainfall erosivity has increased on the TP during the period 1981 to 2020, with 65.91 % of the regions exhibiting an increasing trend and 22.25 % showing significant increases, indicating an intensified risk of water erosion. These findings suggest that the 40-year-high spatial resolution rainfall erosivity dataset can provide accurate data support for a quantitative understanding of soil erosio

关键词： Erosion

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The development of permanent magnet quadrupoles for XIPaf DTL 29

The development of permanent magnet quadrupoles for XIPaf DT...

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29th International Linear Accelerator Conference, LINAC 2018

作者： Wang, B.C. Wang, Z.M. Qiu, M.T. Wei, C.Y. Zheng, S.X. Xing, Q.Z. Guo, Q.K. Du, C.T. Wang, X.W. State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi'an710024 China Department of Engineering Physics Tsinghua University Beijing100084 China Key Laboratory of Particle and Radiation Imaging Tsinghua University Ministry of Education Beijing100084 China Laboratory for Advanced Radiation Sources and Application Tsinghua University Beijing100084 China

ISBN: (纸本)9783954501946

Permanent magnet quadrupoles (PMQs) are developed for the DTL of Xi'an 200 MeV Proton Application Facility (XiPAF). In this paper, we describe the fabrication and measurements for the Halbach-type PMQs. The main procedure of the PMQ manufacture is presented. And the magnetic measurements of PMQs are carried out with the help of vibrating wire, Hall probe and rotating coil respectively. The results show the PMQs are able to meet the requirements of XiPAF DTL. Content from this work may be used under the terms of the CC BY 3.0 licence (© 2018).

关键词： Permanent magnets

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Error study of CPHS DTL after assembly 29

Error study of CPHS DTL after assembly

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29th International Linear Accelerator Conference, LINAC 2018

作者： Ma, P.F. Xing, Q.Z. Tang, R. Lei, Y. Guo, Q.K. Du, C.T. Zheng, S.X. Guan, X.L. Wang, X.W. Wang, B.C. Key Laboratory of Particle and Radiation Imaging Tsinghua University Ministry of Education Beijing100084 China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi'an710024 China Laboratory for Advanced Radiation Sources and Application Tsinghua University Beijing100084 China Department of Engineering Physics Tsinghua University Beijing100084 China

ISBN: (纸本)9783954501946

The Compact Pulsed Hadron Source (CPHS) at Tsinghua University is one multi-purpose pulsed neutron source. The injector of the CPHS is a linac, which mainly consists of a source, a low-energy beam transport line (LEBT), a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The error study of the DTL for CPHS is presented in this paper. The error study can provide the field tolerances in the DTL cavity and the alignment tolerance between the RFQ and DTL. Content from this work may be used under the terms of the CC BY 3.0 licence (© 2018).

关键词： Errors

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Ultrathin microcrystalline hydrogenated Si/Ge alloyed tandem solar cells towards full solar spectrum conversion

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Frontiers of Chemical Science and Engineering 2020年第6期14卷 997-1005页

作者： Yu Cao Xinyun Zhu Xingyu Tong Jing Zhou Jian Ni Jianjun Zhang Jinbo Pang Key Laboratory of Modem Power System Simulation and Control&Renewable Energy Technology Northeast Electric Power UniversityJilin 132012China School of Electrical Engineering Northeast Electric Power UniversityJilin 132012China School of Chemical Engineering Northeast Electric Power UniversityJilin 132012China Key Laboratory of Photo-electronics Thin Film Devices and Technique of Tianjin Institute of Photo-electronic Thin Film Devices and TechnologyCollege of Electronic Information and Optical EngineeringNankai UniversityTianjin 300350China Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong Institute for Advanced Interdisciplinary Research(iAIR)University of JinanJinan 250022China

Thin film solar cells have been proved the next generation photovoltaic devices due to their low cost,less material consumption and easy mass *** them,micro-crystalline Si and Ge based thin film solar cells have advantages of high efficiency and ultrathin absorber *** individual junction devices are limited in photoelectric conversion efficiency because of the restricted solar spectrum range for its specific *** this work,w e designed a nd simulated a multi-junction solar cell with its four sub-cells selectively absorbing the full solar spectrum including the ultraviolet,green,red as well as near infrared range,respectively.B y tuning the G e content,the record efficiency of 24.80%has been realized with the typical quadruple junction structure of a-Si:H/a-Si0.9Ge0.1:H/μc-Si:H/μc-Si0.5Ge0.5:*** further reduce the material cost,thickness dependent device performances have been *** can be found that the design of total thickness of 4μm is the optimal device design in balancing the thickness a nd the *** the design of ultrathin quadruple junction device with total thickness of 2μm is the optimized device design regarding cost and long-term stability with a little bit more reduction in *** results indicated that our solar cells combine the advantages of low cost and high *** work may provide a general guidance rule of utilizing the full solar spectrum for developing high efficiency and ultrathin multi-junction solar cells.

关键词： thin films solar cells quadruple junction solar cell amorphous silicon silicon germanium alloy quantum efficiency

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Realizing High Conversion Efficiency in All-ZrCoSb-Based Half-Heusler Thermoelectric Power Generators

SSRN

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SSRN 2023年

作者： Li, Shan Bao, Xin Yin, Li Ye, Xinli Mao, Jun Zhang, Qian School of Civil Aviation Northwestern Polytechnical University Xi’an710072 China Research & Development Institute Northwestern Polytechnical University in Shenzhen Shenzhen518063 China Yangtze River Delta Research Institute of Northwestern Polytechnical University Suzhou215400 China School of Materials Science and Engineering Institute of Materials Genome & Big Data Harbin Institute of Technology Shenzhen518055 China State Key Laboratory of Advanced Welding and Joining China

ZrCoSb-based thermoelectric materials exhibit promising potential for power generation applications due to their high performance in both p- and n-type constituents. In this work, a newly developed all-ZrCoSb-based module achieves a maximum conversion efficiency of ~9.3% at a temperature difference of 668 K. This high conversion efficiency is enabled by the enhanced average thermoelectric properties for both types of ZrCoSb-based materials via Bi alloying and Sn/Ni doping. The hole and electron carrier concentrations were tuned to match the theoretically predicted optimized values, contributing to high weight mobility and power factor. Additionally, the increased mass and strain field fluctuations enhance point defect scattering, leading to a significant reduction in the lattice thermal conductivity of ZrCoSb. Consequently, peak zT values of ~1.2 and ~1.0 at 973 K were respectively obtained in p-type ZrCo(Sb0.5Bi0.5)0.85Sn0.15 and n-type ZrCo0.85Ni0.15Sb0.5Bi0.5, resulting in high average zT values of ~0.75 and ~0.51 in the temperature of 300 to 973 K. This work underscores the significant potential of all-ZrCoSb-based half-Heuslers in waste heat recovery. © 2023, The Authors. All rights reserved.

关键词： Waste heat

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Tuning of a four-vane RFQ for Xi'an 200 MeV proton application facility 29

Tuning of a four-vane RFQ for Xi'an 200 MeV proton applicati...

引用

29th International Linear Accelerator Conference, LINAC 2018

作者： Yu, X.D. Xing, Q.Z. Guo, Q.K. Ma, P.F. Lei, Y. Zheng, S.X. Li, Y. Wang, S. Liu, K. Guan, X.L. Wang, X.W. Wang, B.C. Zhao, C. Wang, Z.M. Key Laboratory of Particle and Radiation Imaging Tsinghua University Ministry of Education Beijing100084 China Laboratory for Advanced Radiation Sources and Application Tsinghua University Beijing100084 China Department of Engineering Physics Tsinghua University Beijing100084 China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi'an710024 China

ISBN: (纸本)9783954501946

This paper mainly describes the procedures and results of tuning a four-vane Radio Frequency Quadrupole (RFQ) accelerator for the Xi'an 200 MeV Proton Application Facility (XiPAF) project. The 3-meter-long RFQ will accelerate a 50 keV H- beam from the ECR source to 3 MeV, and deliver it to the downstream drift tube linac (DTL) with a peak current of 5 mA, pulse length of 10-40 µs and maximum repetition rate of 0.5. The machining, assembly, and RF tuning of the RFQ cavity has been completed successfully. After tuning, the relative error of the operating quadrupole mode field is within ±2.7%, and the dipole mode component is within ±1.9% of the quadrupole mode. The RFQ now is ready for high-power RF conditioning. Content from this work may be used under the terms of the CC BY 3.0 licence (© 2018).

关键词： Pulse repetition rate

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Resolving Nanograin Morphology and Sub-Grain Nanodomains Via Scanning Probe Acoustic Microscopy in Batio3 Ferroelectric Films for Energy Storage Applications

SSRN

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SSRN 2023年

作者： Ouyang, Jun Xue, Yinxiu Yuan, Meiling Song, Chuanqi Wang, Kun Zhao, Yuyao Cheng, Hongbo Zhu, Hanfei Liu, Chao Institute of Advanced Energy Materials and Chemistry Jinan Engineering Laboratory for Multi-Scale Functional Materials School of Chemistry and Chemical Engineering Qilu University of Technology Shandong Academy of Sciences Shandong Jinan250353 China Key Laboratory of Key Film Materials & Application for Equipment School of Material Sciences and Engineering Xiangtan University Hunan Xiangtan411105 China Key Laboratory for Liquid-Solid Structure Evolution and Processing of Materials Ministry of Education School of Materials Science and Engineering Shandong University Shandong Jinan250061 China Academic Affairs Office Civil Aviation University of China Tianjin300300 China China Tobacco Shandong Industrial Co. Ltd. Shandong Jinan250014 China

Energy storage property of a dielectric is closely tied with its nanostructure. In this study, we aimed to achieve a deep understanding of this relationship in high energy density ferroelectric ceramic films, by probing into the nanograin and sub-grain nanostructures in polycrystalline BaTiO3 films integrated on Si. Through scanning probe acoustic microscopy analyses, it was revealed that the BaTiO3 films directly grown on Pt/Ti/Si consist of large discontinuous columnar nanograins, while those grown on LaNiO3-buffered Pt/Ti/Si substrates display a continuous columnar nanograin microstructure. Furthermore, ultrafine ferroelastic domains of ~ 10 nm wide were revealed inside the grains of the buffered BaTiO3 films, while those unbuffered films showed about ~50% increase in the domain width. The dielectric properties of the BaTiO3 films, including the energy storage performance, are well correlated with their characteristic nanostructures. © 2023, The Authors. All rights reserved.

关键词： Ferroelectric films

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Global Dynamics and Optimal Design of a New Highly Efficient Nonlinear Energy Sink Based on Magnetic-Elastic Impacts with Negative Stiffness

Research Square

引用

Research Square 2021年

作者： Li, Shuangbao Wang, Tingting Chen, Jianen Research Institute of Science and Technology Innovation Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A new highly efficient elastic-impact bistable nonlinear energy sink (EI-BNES) based on magnetic-elastic impacts with negative stiffness and bistability is proposed and optimized through global dynamical analysis. The EI-BNES has better robustness and higher energy dissipation rates with nearly more than 96.5% for broadband impulsive excitations than the traditional cubic NESs and single bistable NESs. The structure of negative stiffness impacts is realized by reasonable layout of permanent ring magnets and springs. A two-degree-of-freedom (two-DOF) elastic-impact system is established to describe the coupled nonlinear interaction between the main structure and the attached EI-BNES. A global Melnikov reduction analysis (GMRA) is proposed to study global dynamics and homoclinic bifurcations of the reduced two-dimensional subsystem, which is used to explain the mechanism of nonlinear targeted energy transfer (TET) and detect the threshold of impulsive amplitudes of EI-BNES for in-well and compound motions between in-well and cross-well resonance responses. A special type of saddle-center equilibrium points is also found in the non-smooth system of the EI-BNES and can be used to effectively increase the energy dissipation rates. The optimal design criterion of the tuned EI-BNES for better dissipation performance is also first discussed based on the GMRA and numerical techniques for calculating the Melnikov function of the non-smooth systems. The effectiveness of the analytical GMRA is also verified by numerical simulations. © 2021, CC BY.

关键词： Stiffness

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Evolution of N = 20, 28, 50 shell closures in the 20 6 Z 6 30 region in deformed relativistic Hartree-Bogoliubov theory in continuum

arXiv

引用

arXiv 2023年

作者： Zheng, Ru-You Sun, Xiang-Xiang Shen, Guo-Fang Geng, Li-Sheng School of Physics Beihang University Beijing102206 China School of Nuclear Science and Technology University of Chinese Academy of Sciences Beijing100049 China Institut für Kernphysik Institute for Advanced Simulation Jülich Center for Hadron Physics Forschungszentrum Jülich JülichD-52425 Germany CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China Peng Huanwu Collaborative Center for Research and Education Beihang University Beijing100191 China Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang University Beijing102206 China Institute of Modern Physics Chinese Academy of Sciences Guangdong Province Huizhou516000 China

Magicity, or shell closure, plays an important role in our understanding of complex nuclear phenomena. In this work, we employ one of the state-of-the-art density functional theories, the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) with the density functional PC-PK1, to investigate the evolution of the N = 20, 28, 50 shell closures in the 20 6 Z 6 30 region. We show how these three conventional shell closures evolve from the proton drip line to the neutron drip line by studying the charge radii, two-neutron separation energies, two-neutron gaps, quadrupole deformations, and single-particle levels. In particular, we find that in the 21 6 Z 6 27 region, the N = 50 shell closure disappears or becomes quenched, mainly due to the deformation effects. Similarly, both experimental data and theoretical predictions indicate that the N = 28 shell closure disappears in the Mn isotopic chain, also predominantly due to the deformation effects. The DRHBc theory predicts the existence of the N = 20 shell closure in the Ca, Sc, and Ti isotopic chains, but the existing data for the Ti isotopes suggests the contrary, and therefore more investigations are needed. Copyright © 2023, The Authors. All rights reserved.

关键词： Neutrons

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