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Simultaneous fluorescence and Compton scattering computed tomography based on linear polarization X-ray

NUCLEAR SCIENCE AND TECHNIQUES 2024年第10期35卷 1-10页

作者： Chi, Zhi-Jun Zhang, Hong-Ze Lin, Jin Zhang, Xuan-Qi Ding, Hao Tian, Qi-Li Zhang, Zhi Du, Ying-Chao Huang, Wen-Hui tang, chuan-xiang Beijing Normal Univ Sch Phys & Astron Minist Educ Key Lab Beam Technol Beijing 100875 Peoples R China Tsinghua Univ Minist Educ Dept Engn Phys Key Lab Particle & Radiat Imaging Beijing 100084 Peoples R China

PurposeTo propose a method for simultaneous fluorescence and Compton scattering computed tomography by using linearly polarized *** Carlo simulations were adopted to demonstrate the feasibility of the proposed method. In the simulations, the phantom is a polytetrafluoroethylene cylinder inside which are cylindrical columns containing aluminum, water, and gold (Au)-loaded water solutions with Au concentrations ranging between 0.5 and 4.0 wt%, and a parallel-hole collimator imaging geometry was adopted. The light source was modeled based on a Thomson scattering X-ray source. The phantom images for both imaging modalities were reconstructed using a maximumlikelihood expectation maximization *** the X-ray fluorescence computed tomography (XFCT) and Compton scattering computed tomography (CSCT) images of the phantom were accurately reconstructed. A similar attenuation contrast problem for the different cylindrical columns in the phantom can be resolved in the XFCT and CSCT images. The interplay between XFCT and CSCT was analyzed, and the contrast-to-noise ratio (CNR) of the reconstruction was improved by correcting for the mutual influence between the two imaging modalities. Compared with K-edge subtraction imaging, XFCT exhibits a CNR advantage for the *** XFCT and CSCT can be realized by using linearly polarized X-rays. The synergy between the two imaging modalities would have an important application in cancer radiation therapy

关键词： X-ray fluorescence computed tomography Compton scattering computed tomography Linear polarization Thomson scattering X-ray source Monte Carlo simulation DUAL-ENERGY CT NANOPARTICLE-LOADED OBJECTS ATTENUATION COEFFICIENTS XFCT PARAMETRIZATION FEASIBILITY ELEMENTS

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A new method to generate relativistic comb bunches with tunable subpicosecond spacing

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Chinese Physics C 2012年第2期36卷 151-155页

作者： DU Ying-Chao HUANG Wen-Hui tang chuan-xiang Accelerator Laboratory Department of Engineering PhysicsTsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China Key Laboratory of High Energy Radiation Imaging Fundamental Science for National Defense Beijing 100084China

We propose and analyze a scheme to produce comb bunches, i.e. a bunch consisting of micro-bunch trains, with tunable subpicosecond spacing. In the scheme, the electron beam is first deflected by a deflecting cavity which introduces a longitudinal-dependent linear transverse kick to the particles. After passing through a drift space, the transverse beam size is linearly coupled to the longitudinal position of the particle inside the beam, and a mask is placed there to tailor the beam, then the mask distribution is imprinted on the beam＇s longitudinal distribution. A quadrupole magnet and another deflecting cavity are used in the beam line to compensate the transverse angle due to the first deflecting cavity. Analysis shows that the number, length, and spacing of the trains can be controlled through the parameters of the deflecting cavity and the mask. Such electron bunch trains can be applied to an infrared free electron laser, a plasma-wakefield accelerator and a supper-radiance THz source.

关键词： bunch trains mask deflecting cavity

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Nonresonant Metamaterials with an Ultra-High Permittivity

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Chinese Physics Letters 2011年第5期28卷 242-244页

作者： HE Xiao-Yang CHEN Qi LI Lin-Cui YANG Chun LI Biao ZHOU Bang-Hua tang chuan-xiang Department of Engineering Physics Tsinghua UniversityBeijing 100084 Institute of Electronic Engineering China Academy of Engineering PhysicsMianyang 621900

A nonresonant structure composed of metal cut-wires for realization of metamaterials is *** kind of metamaterial works at an ultra broad bandwidth with uniform *** analysis and numerical simulations are carried out to study this inclusion and expression for the effective permittivity is *** methods are studied to enhance the permittivity and a nonresonant metamaterial with an ultra-high permittivity is obtained.A demonstration shows that the permittivity of this metamaterial can be as high as 145.

关键词： permittivity realization Permittivity

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稳态微聚束加速器光源

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物理学报 2022年第15期71卷 74-88页

作者：唐传祥邓秀杰清华大学工程物理系北京100084

稳态微聚束(steady-state micro-bunching,SSMB)原理采用激光操控储存环中的电子,可形成具有精微纵向/时间结构的电子束团,即微聚束.通过有机结合微聚束辐射的强相干特性以及储存环内电子束的高回旋频率特性,SSMB光源可提供高平均功率... 详细信息

稳态微聚束(steady-state micro-bunching,SSMB)原理采用激光操控储存环中的电子,可形成具有精微纵向/时间结构的电子束团,即微聚束.通过有机结合微聚束辐射的强相干特性以及储存环内电子束的高回旋频率特性,SSMB光源可提供高平均功率、窄带宽的相干辐射,波段可覆盖从太赫兹到软X射线,具有巨大的科学及产业应用前景.本文在对现有加速器光源—同步辐射光源和自由电子激光简要介绍的基础上,对SSMB的概念及潜力、原理验证实验进展、核心物理及关键技术挑战、清华SSMB-EUV光源方案及其对科学研究和芯片光刻潜在的变革性影响进行总结论述.所综述的工作是在我国自己创新性工作基础上进行的,对于国内读者了解该领域的工作及发展具有一定的帮助.

关键词：加速器光源稳态微聚束原理验证实验极紫外光刻

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Lysogenic phage therapy towards emerging contaminant bioremediation

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Science China Technological Sciences 2024年第10期67卷 3129-3131页

作者： tang xiang ZHOU ShunGui Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry University

Emerging contaminants often arise as by-products of technological advances,(bio)transformation products, or replacements for previously regulated chemicals. Once released into the environment, they present a significant threat to human health within the One Health framework. Among various strategies for contaminant remediation, microbial-based initiatives are particularly promising for the removal and remediation of emerging contaminants due to their environmentally friendly characteristics, such as minimal chemical use and reduced energy consumption.

关键词： BACTERIA GENES

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Intelligent responsive self-assembled micro-nanocapsules: Used to delay gel gelation time

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Petroleum Science 2024年第4期21卷 2433-2443页

作者： chuan-Hong Kang Ji-xiang Guo Dong-Tao Fei Wyclif Kiyingi Unconventional Petroleum Research Institute China University of Petroleum

In the application of polymer gels to profile control and water shutoff,the gelation time will directly determine whether the gel can "go further" in the formation,but the most of the methods for delaying gel gelation time are complicated or have low *** is an urgent need for an effective method for delaying gel gelation time with intelligent *** by the slow-release effect of drug capsules,this paper uses the self-assembly effect of gas-phase hydrophobic SiO2in aqueous solution as a capsule to prepare an intelligent responsive self-assembled *** capsule slowly releases the cross-linking agent under the stimulation of external conditions such as temperature and pH value,thus delaying gel gelation *** the pH value is 2 and the concentration of gas-phase hydrophobic SiO2particles is 10%,the gelation time of the capsule gel system at 30,60,90,and 120℃ is12.5,13.2,15.2,and 21.1 times longer than that of the gel system without containing capsule,*** with other methods,the yield stress of the gel without containing capsules was 78 Pa,and the yield stress after the addition of capsules was 322 *** intelligent responsive self-assembled micronanocapsules prepared by gas-phase hydrophobic silica nanoparticles can not only delay the gel gelation time,but also increase the gel *** slow release of cross-linking agent from capsule provides an effective method for prolongating the gelation time of polymer gels.

关键词： Profile control and water shutoff Polymer gel Delayed gelation time Intelligent response Self-assembled Micro-nanocapsules

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Nutrient enrichment driven by canopy rainfall redistribution:Mechanism,quantification,and pattern

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Science China Earth Sciences 2024年第5期67卷 1529-1544页

作者： chuan YUAN Xiaoping YUE Yafeng ZHANG Yu ZHANG Yanting HU Qiang tang Li GUO Shuai WANG Xingwu DUAN Wenhua xiang Xiaohua WEI Xiaoyan LI College of Forestry and Biotechnology Zhejiang A&F UniversityHangzhou 311300China Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqing 400715China Shapotou Desert Research and Experiment Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China School of Geographical Sciences Hebei Normal UniversityShijiazhuang 050024China Faculty of Life Science and Technology Central South University of Forestry and TechnologyChangsha 410004China State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Yunnan Key Laboratory of Soil Erosion Prevention and Green Development Institute of International Rivers and Eco-securityYunnan UniversityKunming 650091China Department of Earth Environmental and Geographic SciencesUniversity of British Columbia(Okanagan)KelownaBritish Columbia V1V 1V7Canada

Vegetation canopies intercept and redistribute rainfall into throughfall and stemflow,which transfer substantial amounts of elements into the soil,influencing soil microbial community,plant survival,and plant community *** advancements in ecohydrological research,the implication of nutrient enrichment resulting from this redistribution of rainfall by canopies remains largely *** address this gap,we conducted a systematic review of 1020 papers published between 2000 and 2022,gathering data on nutrient concentration and enrichment for critical ions(including K^(+),Na^(+),Ca^(2+),Mg^(2+),NH_(4)^(+),Cl^(-),NO_(3)^(-)and SO_(4)^(2-))from the Web of Science and Chinese Knowledge Infrastructure *** aimed to synthesize the mechanisms,quantify the enrichments,and identify global patterns of nutrient enrichment in stemflow and throughfall across climate zones,and vegetation types and *** results of this study indicate that stemflow exhibits,on average,2.1times greater ion concentration(6.13 mg L^(-1))compared to *** particular,among the investigated ions,SO_(4)^(2-)(12.45and 6.32 mg L^(-1))for stemflow and throughfall,respectively,and Cl^(-)(9.21 and 4.81 mg L^(-1))exhibit the highest concentrations in both rainfall redistribution components,while K^(+)(13.7 and 5.8)and Mg^(2+)(5.6 and 2.8)have the highest enrichment *** climate zones,throughfall and stemflow show the lowest ion concentrations but the highest enrichment factors in extremely humid *** the temperature gradient,ion concentrations are the highest in cold climates with no clear patterns observed for enrichment factors with increasing *** addition,shrubs,conifers,mixed forests,and artificial ecosystems demonstrate enrichment factors 1.1 to 3.0 times greater than those of trees,broad-leaved plants,pure forests,and natural *** findings emphasize the need for increased attentions to artificial ecosystems,such as urban

关键词： Ecohydrology Rainfall redistribution Nutrients transport Enrichment characteristics Climate zones

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Corrosion behaviors and kinetics of nanoscale zero-valent iron in water:A review

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Journal of Environmental Sciences 2024年第1期135卷 391-406页

作者： Chenliu tang Xingyu Wang Yufei Zhang Nuo Liu xiang Hu Research Group of Water Pollution Control and Water Reclamation College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Shanghai Collaborative Innovation Centre for WEEE Recycling School of Resources and Environmental EngineeringShanghai Polytechnic UniversityShanghai 201209China

Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing theoretical guidance for developing a cost-effective nZVI-based technology and designing large-scale ***,this review gives a holistic overview on the corrosion behaviors and kinetics of nZVI in ***,Eh-pH diagram is introduced to predict the thermodynamics trend of iron *** morphological,structural,and compositional evolution of(modified-)nZVI under different environmental conditions,assisted with microscopic and spectroscopic evidence,is then ***,common analytical methods and characterization technologies are categorized to establish time-resolved corrosion kinetics of nZVI in ***,stable models for calculating the corrosion rate constant of nZVI as well as electrochemical methods for monitoring the redox reaction are discussed,emphasizing their capabilities in studying the dynamic iron corrosion ***,in the future,more efforts are encouraged to study the corrosion behaviors of nZVI in long-term practical application and further build nanoparticles with precisely tailored *** expect that our work can deepen the understanding of the nZVI chemistry in aquatic environment.

关键词： Nanoscale zero-valent iron(nZVI) Corrosion behaviors Corrosion kinetics nZVI evolution

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Rhodotron型加速器粒子动力学研究

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高能物理与核物理 2005年第2期29卷 180-185页

作者：陈勇黄文会唐传祥清华大学工程物理系北京100084

Rhodotron是一种新型的CW电子加速器,已经广泛应用于辐照加工的很多领域.本文利用Parmela程序研究其动力学特性,深入分析了束团的同步条件、相聚过程以及在CW工作状态下束团相遇碰撞等一系列纵向动力学问题;并详细探讨了空间电荷效应、... 详细信息

Rhodotron是一种新型的CW电子加速器,已经广泛应用于辐照加工的很多领域.本文利用Parmela程序研究其动力学特性,深入分析了束团的同步条件、相聚过程以及在CW工作状态下束团相遇碰撞等一系列纵向动力学问题;并详细探讨了空间电荷效应、横向聚焦过程的实现、初始参量对横向束流特性的影响等横向动力学问题.在上述研究基础上,计算出束流损失功率的分布,并比较了模拟计算结果与Rhodotron原型机的实际参数,两者的结果基本一致,由此证明了这种研究方法的可行性.

关键词： Rhodotron型加速器粒子动力学横向聚焦束流损失功率分布 CW电子束

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Construction of daily precipitation series and the observational characteristics of extreme precipitation in Tianjin,China during 1888-2022

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Advances in Climate Change Research 2024年第1期15卷 52-61页

作者： Peng SI Qing-xiang LI Xiao-Yang CHEN Min WANG chuan-Jun LUO Tianjin Meteorological Information Center Tianjin Meteorological BureauTianjin 300074China Research Centerfor Ecology and Environment of Central Asia Chinese Academy of SciencesWulumuqi 830011China School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 528478China Key Laboratory of Tropical Amosphere-Ocean System Ministry of EducationZhuhai 528478China Shaoguan Meteorological Service Shaoguan 512028China

Given the difficulties in rescuing and ensuring the quality of long-term climate data,current studies on century-scale climate change are usually limited to annual and monthly data,resulting in the poor detection of extreme climate events and their changes before *** this study,we reconstructed a daily precipitation series for Tianjin from 15 September 1887 to 31 December 2022 on the basis of the most comprehensive daily precipitation records collected from the Tianjin Meteorological Archive,China,and in reference to the precipitation analysis results based on the datasets developed by the Climatic Research Unit Time-Series version 4.06,Global Precipitation Climatology Centre and University of Delaware along with the application of various homogenisation methods for climate *** approach provides a complete and reliable century-long daily precipitation series for the study of regional or local extreme weather and climate *** reconstructed daily dataset reveals that the annual precipitation amount and R95 intensity in Tianjin during 1888-2022 lack significant trends and have values of 0.74±6.99 and-1.84±3.22 mm per decade,*** the annual and seasonal scales,the precipitation amount and R95 intensity,particularly those in autumn,have increased since the latter half of the 20th century relative to those in ***,the increase in precipitation amount and R95 intensity is relatively limited compared with that in atmospheric water vapour content due to surface warming,indicating the highly sensitive response of extreme precipitation events to *** addition,the estimates for the return periods of 5,10,20,50 and 100 years covering 1888-2022,1888-1950 and 1951-2022 depict that the intensity of heavy rain and above magnitude was highest in 1888-1950 and decreased in 1951-2022.

关键词： Over a century-long timescale Daily precipitation series Extreme precipitation Return period

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