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Effect of surface modification on the radiation stability of diamond ohmic contacts

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Chinese Physics B 2024年第2期33卷 444-448页

作者：牟恋希赵上熳王鹏原晓芦刘金龙朱志甫陈良贤魏俊俊欧阳晓平李成明 Institute for Advanced Materials and technology University of Science and Technology BeijingBeijing 100083China School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China School of Information Engineering Zhengzhou University of TechnologyZhengzhou 450044China State Key Laboratory of Intense Pulsed radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

The ohmic contact interface between diamond and metal is essential for the application of diamond *** modification can significantly affect the contact performance and eliminate the interface polarization ***,the radiation stability of a diamond detector is also sensitive to surface *** this work,the influence of surface modification technology on a diamond ohmic contact under high-energy radiation was *** radiation,the specific contact resistivities(ρc)between Ti/Pt/Au-hydrogen-terminated diamond(H-diamond)and Ti/Pt/Au-oxygenterminated diamond(O-diamond)were 2.0×10^(-4)W·cm^(2) and 4.3×10^(-3)Wcm^(2),*** 10 MeV electron radiation,the ρc of Ti/Pt/Au H-diamond and Ti/Pt/Au O-diamond were 5.3×10^(-3)W·cm^(2)and 9.1×10^(-3)W·cm^(2),*** rates of change of ρc of H-diamond and O-diamond after radiation were 2550%and 112%,*** electron radiation promotes bond reconstruction of the diamond surface,resulting in an increase in ρc.

关键词： single crystal diamond ohmic contact surface modification electron radiation

Organochlorides Mediate Oxidation Reactions Induced by Low Dose Ionizing radiation

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CCS Chemistry 2024年第7期6卷 1712-1720页

作者： Juncheng Liu Tobias G.Brevé Bing Xu Peter-Leon Hagedoorn Antonia G.Denkova Rienk Eelkema Department of radiation Science and technology Delft University of Technology2629 JB Delft Department of Chemical Engineering Delft University of Technology2629 HZ Delft Department of Biotechnology Delft University of Technology2629 HZ Delft

The controlled release of drugs using local ionizing radiation presents a promising approach for targeted cancer treatment,particularly when applied in concurrent *** these approaches,radiation-generated reactive species often play an important ***,the reactive species that can be used to trigger release have low yield and lack ***,we demonstrate the generation of highly oxidative species when aqueous solutions containing low concentrations of organochlorides(such as chloroform)are irradiated with ionizing radiation at therapeutically relevant *** reactive species were identified as peroxyl radicals,which formed in a reaction cascade between organochlorides and aqueous *** employed stilbene-based probes to investigate the oxidation process,showing double bond oxidation and *** translate this reactivity into a radiation-sensitive material,we synthesized a micelle-forming amphiphilic block copolymer that has stilbene as the linker between two *** exposure to ionizing radiation,the oxidation of stilbene led to the cleavage of the polymer,which induces the dissociation of the block-copolymer micelles and the release of loaded drugs.

关键词： drug delivery micelles radiation chemistry reactive oxygen species ionizing radiation reaction mechanisms

Insights into the hydrogen evolution reaction in vanadium redox flow batteries:A synchrotron radiation based X-ray imaging study

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Journal of Energy Chemistry 2024年第4期91卷 132-144页

作者： Kerstin Köble Alexey Ershov Kangjun Duan Monja Schilling Alexander Rampf Angelica Cecilia TomášFaragó Marcus Zuber Tilo Baumbach Roswitha Zeis Helmholtz Institute Ulm Karlsruhe Institute of Technology89081 UlmGermany Laboratory for Applications of Synchrotron radiation Karlsruhe Institute of Technology76131 KarlsruheGermany Institute for Photon Science and Synchrotron radiation Karlsruhe Institute of Technology76344 Eggenstein-LeopoldshafenGermany Department of Electrical Electronicsand Communication EngineeringFaculty of EngineeringFriedrich-Alexander-Universität Erlangen-Nürnberg(FAU)91058 ErlangenGermany Department of Mechanical and Industrial Engineering University of TorontoToronto M5S 3G8OntarioCanada

The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency ***,a deeper understanding of this process and the accompanying bubble formation is *** benchmarking study locally analyzes the bubble distribution in thick,porous electrodes for the first time using deep learning-based image segmentation of synchrotron X-ray *** large three-dimensional data set was processed precisely in less than one minute while minimizing human errors and pointing out areas of increased HER activity in *** study systematically varies the electrode potential and material,concluding that more negative electrode potentials of-200 m V *** hydrogen electrode(RHE)and lower cause more substantial bubble formation,resulting in bubble fractions of around 15%–20%in carbon felt ***,the bubble fractions stay only around 2%in an electrode combining carbon felt and carbon *** detected areas with high HER activity,such as the border subregion with more than 30%bubble fraction in carbon felt electrodes,the cutting edges,and preferential spots in the electrode bulk,are potential-independent and suggest that larger electrodes with a higher bulk-to-border ratio might reduce HER-related performance *** described combination of electrochemical measurements,local X-ray microtomography,AI-based segmentation,and 3D morphometric analysis is a powerful and novel approach for local bubble analysis in three-dimensional porous electrodes,providing an essential toolkit for a broad community working on bubble-generating electrochemical systems.

关键词： Vanadium redox flow battery Synchrotron X-ray imaging Tomography Hydrogen evolution reaction Gas bubbles Deep learning

A summary of UNSCEAR evaluation on occupational exposure to ionizing radiation and call for more representative data in broader range of occupational sectors

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radiation Medicine and Protection 2024年第1期5卷 11-15页

作者： Jing Chen United Nations Scientific Committee on the Effects of Atomic radiation Vienna International CentreP.O.Box 5001400ViennaAustria

The annex D of the United Nations Scientific Committee on the Effects of Atomic radiation(UNSCEAR)2020/2021 Report presented a comprehensive global estimate of occupational exposure to ionizing *** worldwide annual number of workers exposed to natural and human-made sources of ionizing radiation was estimated to be approximately 24 million in the period *** 52% of those were employed in the sectors that involve exposure to natural sources of *** worldwide average annual effective dose for all workers during the period 2010-2014 was estimated to be around 1.2 mSv-about two thirds of the value estimated for the period *** annual effective dose was estimated to be around 2.0 mSv for workers exposed to natural sources and 0.5 mSv for workers exposed to human-made *** overriding limitation of current evaluation was the low rate of participation by United Nations Member States in providing occupational exposure monitoring data,especially data from non-nuclear sectors and occupational sectors involving naturally occurring radioactive *** the assessment of the worldwide occupational exposure is a complex task,the Committee relies on the collection of up-to-date data on occupational exposure from United Nations Member States in a broad range of occupational sectors,and continues collaboration with international organizations.

关键词： Occupational exposure Ionizing radiation United Nations Scientific Committee on the Effects of Atomic radiation

A summary of UNSCEAR evaluation on medical exposure to ionizing radiation and call for more representative data

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radiation Medicine and Protection 2024年第1期5卷 7-10页

作者： Jing Chen United Nations Scientific Committee on the Effects of Atomic radiation Vienna International CentreP.O.Box 5001400ViennaAustria

The annex A of the United Nations Scientific Committee on the Effects of Atomic radiation(UNSCEAR)2020/2021 Report presented a comprehensive global estimate of frequencies and doses from medical exposure to ionizing radiation,their distribution and trends for the period *** annex considered four general categories of medical practice using ionizing radiation:(a)diagnostic radiology,including dental radiology and computed tomography,(b)interventional radiology(image-guided interventional procedures),(c)nuclear medicine,and(d)radiation *** the period 2009-2018,about 4.2 billion medical radiological examinations were performed annually,resulting in an annual effective dose of 0.57 mSv per *** use of computed tomography has continued to grow and the contribution from interventional radiology has increased rapidly in recent *** annual number of radionuclide therapy treatments has increased by 60% since the UNSCEAR 2008 Report,while the number of courses of radiation therapy has increased by 22%.Medical exposure remains by far the largest human-made source of radiation exposure to the *** Committee's evaluation relies on the collection of up-to-date and representative exposure data from all Member States of the United *** exposure survey should be more relevant and useful and adapted to changing data sources and changing uses of radiation across the world.

关键词： Medical exposure Ionizing radiation United Nations Scientific Committee on the Effects of Atomic radiation

Wharton’s jelly mesenchymal stem cells: Future regenerative medicine for clinical applications in mitigation of radiation injury

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World Journal of Stem Cells 2024年第7期16卷 742-759页

作者： Prashasti Sharma Dharmendra Kumar Maurya Life Sciences Homi Bhabha National InstituteMumbai 400094MaharashtraIndia radiation Biology&Health Sciences Division Bhabha Atomic Research CentreMumbai 400085MaharashtraIndia

Wharton’s jelly mesenchymal stem cells(WJ-MSCs)are gaining significant attention in regenerative medicine for their potential to treat degenerative diseases and mitigate radiation ***-MSCs are more naïve and have a better safety profile,making them suitable for both autologous and allogeneic *** review highlights the regenerative potential of WJ-MSCs and their clinical applications in mitigating various types of radiation *** this review,we will also describe why WJ-MSCs will become one of the most probable stem cells for future regenerative medicine along with a balanced view on their strengths and ***,the most updated literature related to both preclinical and clinical usage of WJ-MSCs for their potential application in the regeneration of tissues and organs will also be compiled.

关键词： Stem cells Wharton’s jelly mesenchymal stem cells Radiotherapy Xerostomia Lung fibrosis

The biochemical behavior and mechanism of uranium(Ⅵ)bioreduction induced by natural Bacillus thuringiensis

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Journal of Environmental Sciences 2024年第2期136卷 372-381页

作者： Shunzhang Chen Junyuan Gong Yanxia Cheng Yuqi Guo Feize Li Tu Lan Yuanyou Yang Jijun Yang Ning Liu Jiali Liao Key Laboratory of radiation Physics and technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

For a broader understanding of uranium migration affected by microorganisms in natural anaerobic environment,the bioreduction of uranium(Ⅵ)(U(Ⅵ))was revealed in Bacillus thuringiensis,a dominant bacterium strain with potential of uranium-tolerant isolated from uranium contaminated *** reduction behavior was systematically investigated by the quantitative analysis of U(Ⅳ)in bacteria,and mechanism was inferred from the pathway of electron *** anaerobic conditions,appropriate biomass and sodium lactate as electron donor,reduction behavior of U(Ⅵ)induced by *** was restricted by the activity of lactate dehydrogenase,which was directly affected by the initial pH,temperature and initial U(Ⅵ)concentration of bioreduction *** of U(Ⅵ)was driven by the generation of nicotinamide adenine dinucleotide(NADH)from enzymatic reaction of sodium lactate with various *** transmission of the electrons from bacteria to U(Ⅵ)was mainly supported by the intracellular NADH dehydrogenase-ubiquinone system,this process could maintain the biological activity of cells.

关键词： Uranium Bacillus thuringiensis Bioreduction Electron transmission

Quick-scanning X-ray absorption fine structure beamline at SSRF

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Nuclear Science and Techniques 2024年第6期35卷 1-13页

作者： Yu Chen Qian Gao Zheng Jiang Jiong Li Shuo Zhang Shanghai Synchrotron radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China National Synchrotron radiation Laboratory University of Science and Technology of ChinaHefei 230029China

The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described ***11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine *** is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection *** can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 *** performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental *** paper presents an overview of the beamline design and a detailed description of its performance and capabilities.

关键词： Bending magnet beamline X-ray absorption fine structure Quick-scanning XAFS In situ Synchrotron radiation

In situ luminescence measurements of GaN/Al_(2)O_(3) film under different energy proton irradiations

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Chinese Physics B 2024年第5期33卷 704-710页

作者：蒋文丽欧阳潇仇猛淋英敏菊陈琳庞盼张春雷张耀锋廖斌 Key Laboratory of Beam technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of radiation technology Beijing Academy of Science and TechnologyBeijing 100875China

Ion beam-induced luminescence(IBIL) experiments were performed to investigate the in situ luminescence of GaN/Al_(2)O_(3) at varying ion energies,which allowed for the measurement of defects at different depths within the *** energies of H^(+)were set to 500 keV,640 keV and 2 MeV,the Bragg peaks of which correspond to the GaN film,GaN/Al_(2)O_(3) heterojunction and Al_(2)O_(3) substrate,respectively.A photoluminescence measurement at 250 K was also performed for comparison,during which only near band edge(NBE) and yellow band luminescence in the GaN film were *** evolution of the luminescence of the NBE and yellow band in the GaN film was discussed,and both exhibited a decrease with the fluence of H^(+).Additionally,the luminescence of F centers,induced by oxygen vacancies,and Cr^(3+),resulting from the ^(2)E →^(4)A_(2) radiative transition in Al_(2)O_(3),were measured using 2 MeV H^(+).The luminescence intensity of F centers increases gradually with the fluence of H^(+).The luminescence evolution of Cr^(3+)is consistent with a yellow band center,attributed to its weak intensity,and it is situated within the emission band of the yellow band in the GaN *** results show that IBIL measurement can effectively detect the luminescence behavior of multilayer films by adjusting the ion *** measurement can be excited by various techniques,but IBIL can satisfy in situ luminescence measurement,and multilayer structural materials of tens of micrometers can be measured through IBIL by adjusting the energy of the inducing *** evolution of defects at different layers with ion fluence can be obtained.

关键词： ion beam-induced luminescence(IBIL) GaN/Al_(2)O_(3) ion beam