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Transmission of 18 keV negative ions Cl^-through nanocapillariesin Al_2O_3 membrane

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Chinese Physics B 2011年第1期20卷 316-321页

作者：吕学阳陈林陈熙萌贾娟娟周鹏周春林邱玺玉邵剑雄崔莹尹永智王宏伟姬明超 School of Nuclear Science and Technology Lanzhou University

We investigate the angular distribution of the transmitted 18keV negative ions Cl- through Al2O3 nanocapillaries of 50 nm in diameter and 10 μm in length. Elastic scattering ions and inelastic scattering ions are obtained simultaneously. The experimental result is partially consistent with the guiding effect. We can qualitatively explain our experimental result through a dynamic process.

关键词： nanocapillaries negative ions angular distribution guiding effect

An Obliquely Propagating Electromagnetic Lower-Hybrid-Drift Instability in Plasmas with negative ions

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Plasma Science and Technology 2007年第4期9卷 388-393页

作者：王飞虎张宙陈银华黄凤 CAS Key Laboratory of Basic Plasma Physics Department of Modern PhysicsUniversity of Science and Technology of ChinaHefei 230026China

In this study, by employing a local fluid theory for warm plasma containing negative ions, an obliquely propagating electromagnetic instability in the lower hybrid frequency range driven by cross-field currents or relative drifts between electrons and ions was investigated. It is found that the growth rate of the lower-hybrid-drift instability （LHDI） can be controlled by appropriate selection of the propagation direction, the wave number and the relative population of the negative ions.

关键词： lower-hybrid-drift frequency instability negative ions local fluid theory

Episodes of thoron exposure due to consumer products claiming health benefits of negative ions

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辐射防护 2020年第6期40卷 625-630页

作者： Jaiki Lee Korean Association for Radiation Protection SeoulKorea

In May 2018,the primetime news casted a shocking report saying that radon concentration on a certain model of bed mattress found to be as high as 2200 Bq/*** a humble,the Nuclear Safety and Security Commission(NSSC)of Korea confirmed that significant amount of thoron gas is emanated from several mattress models marketed by a company claiming beneficial health effects of negative *** analysis showed that some internal fabric sheets of those mattresses contain high concentration of *** was revealed that the manufacture treated the material with so-called‘negative ion powder’procured from the market and NSSC found that its radioactive content is the monazite *** measurements with reliable instruments resulted in somewhat lower values,the tentative but conservative estimates of doses to the users are still remarkable,ranging from a few to 14 mSv a *** of the affected models have been marketed from 2010 but earlier models,with lower thorium content,were supplied from *** many as 88,000 mattresses have been *** manufacturer with help of the government,recalled all the affected models and separated the radioactive internals.A large amount of waste is waiting for the government decision on disposal *** problems were identified in other consumer products including latex mattresses and pillows imported,hot pads,and several models of sanitary or health-aid *** episodes called for revisiting NORM control strategy in Korea.

关键词： negative ions health effect myth consumer products monazite thoron exposure

Development of Powerful RF Plasma Sources for Present and Future NBI Systems

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Plasma Science and Technology 2004年第1期6卷 2135-2140页

作者： E.Speth NBI-Team Max-Planck-Institut fiir Plasmaphysik 85748 Garching Germany EURATOM-AssociationMax-Planck-Institut fiir Plasmaphysik 85748 Garching Germany EURATOM-Association

This paper deals with the topic of RF plasma sources and their application inhigh-power neutral beam heating systems for nuclear fusion devices. RF sources represent aninteresting alternative to the conventional arc discharge sources. Due to the absence of hotfilaments they exhibit an inherent simplicity both in mechanical and electrical aspects andconsequently offer advantages in terms of cost savings, gain in availability and reliability andreduced maintenance. This renders the RF plasma source attractive for any long pulse (> 10 sec) NBIsystem and in particular for the ITER NBI system. The latter, however, requires that the RF plasmasource is also capable of delivering negative rather than positive hydrogen ions. In the first partof the paper the types, characteristics and operation experience of RF plasma sources for positiveions in operation are described. The second part is devoted to the development for ITER NBI: thebasic requirements, physics and technology issues and the present status are discussed.

关键词： neutral beam injection negative ions RF plasma source

Impact of ionizers on prevention of airborne infection in classroom

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Building Simulation 2023年第5期16卷 749-764页

作者： Chen Ren Fariborz Haghighat Zhuangbo Feng Prashant Kumar Shi-Jie Cao School of Architecture Southeast University2 SipailouNanjing 210096China Energy and Environment Group Department of BuildingCivil and Environmental EngineeringConcordia UniversityMontrealH3G 1M8Canada Global Centre for Clean Air Research(GCARE) School of SustainabilityCivil&Environmental EngineeringFaculty of Engineering&Physical SciencesUniversity of SurreyGuildford GU27XHSurreyUK Institute for Sustainability University of SurreyGuildford GU27XHSurreyUK

Infectious diseases(e.g.,coronavirus disease 2019)dramatically impact human life,economy and social *** the low-cost and energy-saving approaches is essential in removing infectious virus particles from indoors,such as in *** application of air purification devices,such as negative ion generators(ionizers),gains popularity because of the favorable removal capacity for particles and the low operation ***,small and portable ionizers have potential disadvantages in the removal efficiency owing to the limited horizontal diffusion of negative *** study aims to investigate the layout strategy(number and location)of ionizers based on the energy-efficient natural ventilation in the classroom to improve removal efficiency(negative ions to particles)and decrease infection *** infected students were considered in the *** simulations of negative ion and particle concentrations were performed and validated by the *** showed that as the number of ionizers was 4 and 5,the removal performance was largely improved by combining ionizer with natural *** with the scenario without an ionizer,the scenario with 5 ionizers largely increased the average removal efficiency from around 20%to 85%and decreased the average infection risk by 23%.The setup with 5 ionizers placed upstream of the classroom was determined as the optimal layout strategy,particularly when the location and number of the infected students were *** work can provide a guideline for applying ionizers to public buildings when natural ventilation is used.

关键词： classroom infection risk ionizer negative ions removal efficiency

Electron flux distributions in photodetachment of HF^- near an interface: Theoretical imaging method study

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Chinese Physics B 2013年第1期22卷 187-190页

作者： Maryam Nawaz Awan A. Afaq Centre of Excellence in Solid State Physics University of the Punjab Lahore-54590 Pakistan

The electron flux distributions in the photodetachment of HF- near an interface are studied using a two-center model and the theoretical imaging method. An analytical expression for electron flux distributions is derived, which displays oscillations on an observation plane similar to the recent results published by Wang but in the presence of a static electric field. We also discuss the expressions for soft and hard wall cases in detail. A comparison is made with the previous work. The expression is a more general result, and we can deduce from it the electron flux distributions for the photodetachment of H2 near an interface. Finally, we show that the expression reveals similar results as those in [Chin. Phys. B 19 020306 （2010）] when the wall effect is neglected.

关键词： negative ions two-center model electron flux quantum interference

Sheath Structure of an Electronegative Plasma

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Chinese Physics Letters 2003年第9期20卷 1537-1539页

作者：正正汹刘金远邹秀刘悦王晓钢 StateKeyLaboratoryofMaterialsModificationbyLaser ElectronandIonBeamsDalianUniversityofTechnologyDalian116024

We investigate the sheath structure of an electronegative plasma at steady state with the assumptions of cold positive ions and hot negative ions. The modified Bohm criterion is obtained with the Sagdeev potential by introducing a modified ion sound velocity. At the same time the electric potential, net space charge and particles densities in the sheath are analysed in several cases of different temperature ratios of electrons to negative ions and different density ratios of negative ions to positive ions.

关键词： negative ions

Homogeneous catalytic wet air oxidation for the treatment of textile wastewaters

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Journal of Environmental Sciences 2000年第4期12卷 410-415页

作者： Lei, L. Sun, Y. Dept. of Envtl. Science and Engrg. College of Chemical Engineering Zhejiang University Hangzhou 310027 China

An extensive series of experiments was carried out in order to identify suitable catalysts to boost the reaction rate of wet air oxidation of real textile wastewaters at relatively mild temperature and pressure. Experimental results indicated that all catalysts tested in this investigation had shown an impressive increase in the initial COD and TOC removal rate as well as the COD and TOC removal levels in two hours reaction. Among all the catalysts tested, copper salts were more effective than the rest. Anions of the salt solutions also played a role in the catalytic process with nitrate ions having better effect than sulfate ions. Hence copper nitrates were more effective than copper sulfates. It was also found that a mixture of salts with different metals performed better than either of the component single salt alone.

关键词： Catalysis Chemical oxygen demand Copper compounds Low temperature effects negative ions Nitrates Oxidation Pressure effects Rate constants Salts

The Effects of Spherical Surface and Laser Polarization on the Photodetachment Cross Section of H^-

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Communications in Theoretical Physics 2013年第3期59卷 356-360页

作者： Muhammad Haneef Suneela Arif Jehan Akbar Nasrullah Shah Muhammad Zahir Aneela Shamim Hameed Ullah Lab of Atom and Quantum Interference Department of PhysicsHazara UniversityGarden CampusMansehraPakistan Department of Chemistry Abdul Wali Khan UniversityMardanPakistan Department of Statistics University of PeshawarPakistan Department of Chemistry Hazara UniversityGarden CampusMansehraPakistan

We report the combined effects of laser polarization and curvature of the spherical surface on the detached electron spectra from H-. The Theoretical imaging method is used as a tool of investigation. The photodetachment cross sections for various polaxization angles, radii of curvatures and inter ion surface distances axe displayed. The analysis of the spectra reveals that the laser polarization angle θL, curvature of the surface τc and inter ion surface distance d strongly affect oscillations in the spectra. Therefore, a fine control on the laser polaxization and that of curvature in the surface can be used to control oscillations in the photodetachment of negative ions.

关键词： negative ions photodetachment spherical surface