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验证单源CT和双源CT利用调制传递函数评估时间分辨力的研究

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国际医学放射学杂志 2008年第A6期31卷 493-493页

作者： d.ertel E.Krber Y.Kyriakou O.Langner W.A.Kalender 张朝晖 Institute of Medical Physics University of Erlangen-Nrnberg Henkestrasse 9191052 ErlangenGermany.

本研究的目的是在单源CT和双源CT上验证一种利用三维心动自控装置测量时间分辨率的方法,它不依赖于生产商,有质量保证。

关键词：时间分辨力 CT 心脏扫描单源调制传递函数质量保证自控装置双节段扫描设备时间函数

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大螺距双源螺旋心脏CT的可行性研究

国际医学放射学杂志 2009年第6期 601-601页

作者： d.ertel M.M.Lell F.Harig T.Flohr B.Schmidt W.A.Kalender 肖芳 Institute of Medical Physics University of Erlangen NürnbergHenkestraβe 9191052 ErlangenGermany

螺旋CT螺距的增加减少了数据采集时间,双源CT(dSCT)具有较高的时间分辨率,本研究评价这两种特性组合后的价值。所采用的双源CT配备容许螺距因子P=0.35～3.0的原装软件。测量层面灵敏度作为螺距的函数,来评估Z轴空间分辨率,采用结构周期性移

关键词：双源大螺距螺旋心脏 CT

Snapshot imaging of ultrashort electron bunches

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Light(Science & Applications) 2024年第7期13卷 1226-1228页

作者： Andreas döpp Ludwig-Maximilian-Universität München Am Coulombwall 185748GarchingGermany Max Planck Institut für Quantenoptik Hans-Kopfermann-Strasse 1Garching85748Germany

New measurements combine spatial and temporal information from optical transition radiation to estimate the three-dimensional structure of electron bunches from a laser wakefield accelerator.

关键词： ultrashort Snapshot electron

Influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 563-580页

作者： N.HUMNEKAR d.SRINIVASACHARYA department of Mathematics National Institute of TechnologyWarangal 506004TelanganaIndia

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is *** darcyBrinkman model is used to characterize the fluid flow dynamics in porous *** analytical solutions are obtained for the unidirectional and completely developed *** on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is *** eigenvalue problem is then solved by the spectral ***,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing *** results show that increasing the darcy number,the Lewis number,the dufour parameter,or the Soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the ***,the flow is the most unstable when the channel is vertically oriented.

关键词： nanofluid inclined channel variable viscosity linear stability double dif-fusion porous medium

Improved Leap-frog Method for Time-domain Fault Location

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 670-674页

作者： Izudin džafić Rabih A.Jabr Faculty of Electrical Engineering University of SarajevoSarajevo 71000Bosnia and Herzegovina department of Electrical and Computer Engineering American University of BeirutBeirut 11072020Lebanon IEEE

The partial differential equation(PdE)solution of the telegrapher is a promising fault location method among time-domain and model-based *** research works have shown that the leap-frog process is superior to other explicit methods for the PdE ***,its implementation is challenged by determining the initial conditions in time and the boundary conditions in *** letter proposes two implicit solution methods for determining the initial conditions and an analytical way to obtain the boundary conditions founded on the signal *** results show that the proposal gives fault location accuracy superior to the existing leap-frog scheme,particularly in the presence of harmonics.

关键词： Fault location leap-frog partial differential equation time-domain analysis transmission line

The Effect of External Magnetic Field on Electron Scale Kelvin–Helmholtz Instability

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Research in Astronomy and Astrophysics 2024年第9期24卷 236-247页

作者： d.Tsiklauri Joule Physics Laboratory School of ScienceEngineering and EnvironmentUniversity of SalfordManchesterM54WTUK

We use particle-in-cell,fully electromagnetic,plasma kinetic simulation to study the effect of external magnetic field on electron scale Kelvin–Helmholtz instability(ESKHI).The results are applicable to collisionless plasmas when,e.g.,solar wind interacts with planetary magnetospheres or a magnetic field is generated in AGN *** find that as in the case of magnetohydrodynamic(MHd)KHI,in the kinetic regime,the presence of an external magnetic field reduces the growth rate of the *** the MHd case,there is a known threshold magnetic field for KHI stabilization,while for ESKHI this is to be analytically *** a kinetic analytical expression,we use several numerical simulation runs to establish an empirical dependence of ESKHI growth rate,Γ(B_(0))ω_(pe),on the strength of the applied external magnetic *** find the best fit is hyperbolic,Γ(B_(0))ω_(pe)=Γ_(0)ω_(pe)/(A+BB_(0)),where Γ_(0) is the ESKHI growth rate without an external magnetic field and B_(0)=B_(0)/B_(MHd)is the ratio of external and two-fluid MHd stability threshold magnetic field,derived *** analytical theory to back up this growth rate dependence on the external magnetic field is *** results suggest that in astrophysical settings where a strong magnetic field pre-exists,the generation of an additional magnetic field by the ESKHI is suppressed,which implies that nature provides a“safety valve”—natural protection not to“over-generate”magnetic field by the ESKHI ***,we find that our two-fluid MHd threshold magnetic field is the same(up to a factor √γ_(0))as the dC saturation magnetic field,previously predicted by fully kinetic theory.

关键词： instabilities magnetic fields plasmas Sun:heliosphere ISM:magnetic fields

decomposition mechanisms of nuclear-grade cationic exchange resin by advanced oxidation processes:Statistical molecular fragmentation model and dFT calculations

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Journal of Environmental Sciences 2024年第1期135卷 433-448页

作者： Xiang Meng Pierre désesquelles Lejin Xu department of Nuclear Engineering and Technology School of Energy and Power EngineeringHuazhong University of Science&TechnologyWuhan 430074China CNRS Laboratoire de Physique des Gaz et des PlasmasUniversitéParis-SaclayOrsay 91405France State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The treatment and disposal of radioactive waste are presently facing great *** ion exchange resins have become a focus of attention due to their high production and serious environmental *** this paper,a simplified model of cationic exchange resin is proposed,and the degradation processes of cationic resin monomer initiated by hydroxyl radicals(·OH)are clarified by combining statistical molecular fragmentation(SMF)model and density functional theory(dFT)*** prediction of active sites indicates that the S-O bonds and the C-S bond of the sulfonic group are more likely to react during the *** meta-position of the sulfonic group on the benzene ring is the most active site,and the benzene ring without the sulfonic group has a certain *** C11-C14 and C17-C20 bonds,on the carbon skeleton,are the most easily *** is also found that dihydroxy addition and elimination reactions play a major role in the process of desulfonation,carbon skeleton cleavage and benzene ring *** decomposition mechanisms found through the combination of physical models and chemical calculations,provide theoretical guidance for the treatment of complex polycyclic aromatic hydrocarbons.

关键词： Cationic exchange resin Statistical molecular fragmentation model density functional theory Hydroxyl radical decomposition mechanism

Role of pituitary adenylate cyclase-activating polypeptide in peripheral nerve regeneration:a cellular and molecular perspective

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Neural Regeneration Research 2024年第7期19卷 1429-1430页

作者： Grazia Maugeri Velia d’Agata Section of Anatomy Histology and Movement SciencesDepartment of Biomedical and Biotechnological SciencesUniversity of CataniaCataniaItaly

Neuro regeneration is a very complex phenomenon characterized by the generation of new neurons and synapses,involving connections between adjacent cells and axonal *** supplies additional longterm resources to replace... 详细信息

关键词： replace functional regeneration

Process engineering of demineralisation of moderate to high ash Indian coals through NaOH‑HCl leaching and HF leaching

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International Journal of Coal Science & Technology 2024年第2期11卷 111-122页

作者： Heena dhawan d.K.Sharma ANRF Ministry of ScienceNew DelhiIndia department of Energy Science and Engineering Indian Institute of Technology DelhiNew Delhi 110016India

Chemical leaching of coals would be required to produce cleaner coals for some special applications where physical benefi-ciation may not be effective *** would also help in recovering Li and rare earth metals besides in the sequestration of CO_(2).About 20 Indian coals having complexly distributed moderate to high ash contents were sequentially treated with various alkali–acid such as NaOH-HCl,HF,HCl,HCl-HF,and NaOH-HCl-HF *** aimed to establish and design the best stepwise sequential process for the highest degree of demineralisation through a chemical leaching *** and process intensification studies were carried *** than 80%demineralisation of Madhaipur and Neemcha coals was observed using the best sequential treatment designed *** repeated stepwise treatment of the alkali and the acid was also studied,which was found to significantly enhance the degree of demineralisation of *** integrated process of alkali–acid leaching followed by solvent extraction(Organo-refining)and vice versa of the treated coal was also studied for producing cleaner coals.

关键词： Alkali–acid leaching demineralisation Integrated process Rare earth elements