检索结果-南通市图书馆

Trends in characteristics of neurologists who provide stroke consultations in the UsA,2008-2021

stroke & Vascular Neurology 2023年第1期8卷 86-88页

作者： Carter h Nakamoto Andrew D Wilcock Lee h schwamm jennifer j Majersik Kori s Zachrison Ateev Mehrotra Department of health Care Policy Harvard Medical SchoolBostonMassachusettsUSA Department of Family Medicine University of Vermont Larner College of MedicineBurlingtonVermontUSA Department of Neurology Massachusetts General HospitalBostonMassachusettsUSA Department of Neurology University of UtahSalt Lake CityUtahUSA Department of Emergency Medicine Massachusetts General HospitalBostonMassachusettsUSA Division of General Medicine and Primary Care Beth Israel Deaconess Medical CenterBostonMassachusettsUSA

Introduction Patients with acute ischaemic strokes(AIs),on average,fare better with timely neurologist consultation,and a growing proportion of them receive ***,little is known about trends in the characteristics of neurologists who treat *** We identified AIs and transient ischaemic attack(TIA)episodes with neurologist consults in fee-for service Medicare from january 2008 to september *** each episode,we determined whether the neurologist was a vascular neurologist,was a high-volume provider,whether the patient was transferred between hospitals and the distance between the patient’s home and physician’s *** From 2008 to 2021,the share of AIs/TIA episodes(n=5073294)with neurologist consults increased(52.9%to 61.7%).Among episodes with consults,the fraction conducted by a vascular neurologist(5.2%to 13.7%)or by a high-volume neurologist(13.2%to 14.9%)also *** fraction with the patient’s home and neurologist greater than 100 miles apart(4.8%to 9.6%)or in different states(5.1%to 8.1%)increased,as did the fraction with transfers(4.2%to 8.5%).Discussion Over the study period,the proportion of AIs/TIA episodes with consultations from neurologists with either vascular neurology certifications or high volumes increased substantially.

关键词： acute characteristics consultation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A New X-Ray Tidal Disruption Event Candidate with Fast Variability

引用

Research in Astronomy and Astrophysics 2022年第5期22卷 28-35页

作者： j.hampel s.Komossa j.Greiner T.h.Reiprich M.Freyberg T.Erben Argelander-Institut für Astronomie Aufdem Hugel 71D-53121 BonnGermany Max-Planck Institut für Radioastronomie Auf dem Hugel 69D-53121 BonnGermany National Astronomical Observatories Chinese Academy of ScienceBeijing 100101China Max-Planck Institute für Extraterrestrische Physik GieBenbachstrasse 1D-85748 GarchingGermany

During a close encounter between a star and a supermassive black hole,the star can get disrupted by the black hole’s tidal forces,resulting in a tidal disruption event(TDE).The accretion of the star’s material onto the black hole produces strong emission in different wavelength *** we report the discovery with the Roentgen satellite(ROsAT)of an X-ray-selected transient source in an optically non-active *** the location R.A.:13h31m57s.66 and decl.:-32°43’19".7 a sudden rise in X-ray luminosity by a factor of 8 within 8 days has been ***,a very soft X-ray spectrum with a blackbody temperature kT=0.1 keV and a peak luminosity of at least 1×10^(43)erg s^(-1)suggests a TDE interpretation,and the observed properties are very similar to previously identified soft X-ray(ROsAT)*** optical spectrum taken of the galaxy at the position of RXj133157.6324319.7 six years after the X-ray outburst does not show any emission lines as would be expected from a persistent active galactic *** redshift of the galaxy is determined to be 0.051 based on absorption *** is therefore likely a member of the galaxy cluster *** rise in X-ray luminosity happens within 8 days and thus appears to be fast for such an *** X-ray emission was detected 170 days before and 165 days after the event,and none was detected 25 yr later with the Neil Gehrels swift *** change in X-ray luminosity is at least a factor of 40.

关键词： accretion-black holes-galaxies-tidal disruption-X-ray sources

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimentally validated atomistic simulation of the effect of relevant grinding parameters on work piece topography,internal stresses,and microstructure

引用

Friction 2022年第4期10卷 608-629页

作者： s.j.EDER P.G.GRÜTZMAChER T.sPENGER h.hECKEs h.ROjACZ A.NEVOsAD F.hAAs AC2T research Gmbh Viktor-Kaplan-Straße 2/CWiener Neustadt 2700Austria Institute of Engineering Design and Product Development TU WienLehárgasse 6-Objekt 7Vienna 1060Austria Institute of Production Engineering Graz University of TechnologyKopernikusgasse 24/IGraz 8010Austria Tyrolit-schleifmittelwerke swarovski K.G. Swarovskistraße 33Schwaz 6130Austria

In this work,we present a fully atomistic approach to modeling a finishing process with the goal to shed light on aspects of work piece development on the microscopic scale,which are difficult or even impossible to observe in experiments,but highly relevant for the resulting material *** a large-scale simulative parametric study,we varied four of the most relevant grinding parameters:The work piece material,the abrasive shape,the temperature,and the infeed *** order to validate our model,we compared the normalized surface roughness,the power spectral densities,the steady-state contact stresses,and the microstructure with proportionally scaled macroscopic experimental *** the grain sizes vary by a factor of more than 1,000 between experiment and simulation,the characteristic process parameters were reasonably reproduced,to some extent even allowing predictions of surface quality degradation due to tool *** the experimentally validated model,we studied time-resolved stress profiles within the ferrite/steel work piece as well as maps of the microstructural changes occurring in the near-surface *** found that blunt abrasives combined with elevated temperatures have the greatest and most complex impact on near-surface microstructure and stresses,as multiple processes are in mutual competition here.

关键词： large-scale molecular dynamics surface quality microstructure Revolutions per minute-synchronous Grinding(RPM-synchronous Grinding) tool wear

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

hetero-deformation promoted strengthening and toughening in BCC rich eutectic and near eutectic high entropy alloys

引用

journal of Materials science & Technology 2023年第15期146卷 1-9页

作者： D.h.Chung j.Lee Q.F.he Y.K.Kim K.R.Lim h.s.Kim Y.Yang Y.s.Na Department of special Alloys Extreme Materials Research InstituteKorea Institute of Materials ScienceChangwonThe Republic of Korea Department of Mechanical Engineering City University of Hong KongKowloon TongKowloonHong KongChina Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyPohangThe Republic of Korea Center for heterogenic Metal Additive Manufacturing Pohang University of Science and TechnologyPohangThe Republic of Korea Department of Materials science and Engineering City University of Hong KongKowloon TongKowloonHong KongChina

heterostructured eutectic high-entropy alloys(EhEAs)have attracted significant attention owing to their novel properties,such as balanced combinations of strength and fracture ***,the toughening/strengthening mechanisms of these EhEAs have not been thoroughly *** this study,we developed a series of dual-phase Al_((18–2x))Co_(30)Cr_((11+x))Fe_((11+x))Ni_(3)0(x=-1,0,1)eutectic and neareutectic hEAs containing face-centered cubic(FCC)and body-centered cubic(BCC)*** the high amount of BCC,which is referred to as the brittle phase,newly developed EhEAs exhibited superior fracture ***,we discovered that a fully eutectic hEA exhibited further improvements in both yield stress and fracture toughness,outperforming our off-eutectic and other previously reported *** combining experiments and theoretical models,we demonstrated that the synergistic increase in both strength and toughness in our fully eutectic hEA was derived from the high hetero-deformationinduced(hDI)strengthening/toughening associated with a high misorientation angle at the grain/phase boundaries.

关键词： Eutectic high entropy alloy Fracture toughness heterogeneous structure hetero deformation induced strengthening Misorientation angle

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Interface dominated deformation transition from inhomogeneous to apparent homogeneous mode in amorphous/amorphous nanolaminates

引用

journal of Materials science & Technology 2022年第4期99卷 178-183页

作者： Z.Q.Chen M.C.Li j.s.Cao F.C.Li s.W.Guo B.A.sun h.B.Ke W.h.Wang songshan Lake Materials Laboratory Dongguan 523808PR China Institute of Physics Chinese Academy of SciencesBeijing 100190PR China Institute of Materials Engineering Nanjing UniversityNantong 226019PR China school of Physics science and Technology Xinjiang UniversityXinjiang 830046PR China school of Physical sciences University of Chinese Academy of SciencesBeijing 100049PR China state Key Laboratory for Mechanical Behavior of Material Xi'an Jiaotong UniversityXi’an 710049PR China

The amorphous/amorphous nanolaminates(A/ANLs)have aroused great attentions owing to their tunable structure and enhanced mechanical ***,the plastic deformation mechanism of A/ANLs have yet been ***,we systematically examined the mechanical properties and deformation behavior of series of NiNb/ZrCuNi Al A/ANLs via nanoindentaion *** was found that both the amount and morphology of amorphous/amorphous interface(A/AIs)played crucial roles in the plastic deformation of A/*** and straighter A/AIs facilitated multiple shear banding deformation,of which the hardness increased with decreasing layer thickness,as the A/AIs hindered the propagation of shear bands(sBs).Whilst,more and wavier A/AIs promoted homogeneous deformation,of which the hardness stayed at a much lower value and was relatively irrelevant with the layer thickness,for the promoted activation of shear transformation zones by A/*** results provide guidance for modifying the mechanical properties of amorphous alloys with interface engineering design.

关键词： Amorphous alloys Nanolaminates shear bands hardness Interface

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Down-and up-conversion processes in Nd^(3+)/Yb^(3+)co-doped sodium calcium silicate glasses with concomitant Yb^(2+)assessment

引用

journal of Rare Earths 2023年第3期41卷 342-348,I0001页

作者： R.F.Muniz V.s.Zanuto M.s.Gibin j.V.Gunha A.Novatski j.h.Rohling A.N.Medina M.L.Baesso Departament of science State University of MaringáAv.Reitor Zeferino Vaz s/nGoioerê87360-000PRBrazil Departament of Physics State University of MaringáAv.Colombo 5790Maringá87020-900PRBrazil Departament of Physics State University of Ponta GrossaAv.Carlos Cavalcanti4748Ponta Grossa 84030-900PRBrazil

Novel Nd^(3+)/Yb^(3+)co-doped sodium calcium silicate glasses were prepared by melting quenching method:spectroscopic study was carried out as a function of doping content by fixing sensitizer(Nd^(3+))concentration to 0.2 mol%and adjusting activator(Yb^(3+))from 0 to 1.0 mol%.The energy transfer(ET)mechanisms between Nd^(3+)and Yb^(3+)are discussed based on their energy levels and excitation powerdependence emission *** show that the presence of Yb^(2+)might be considered for the Nd^(3+)-free and co-doped *** ET was confirmed by the down-conversion NIR emission spectra of the doped and co-doped samples under excitation at 808 *** mechanisms observed seem to involve only one VIs absorbed photon for each NIR emitted via direct energy transfer between^(4)F_(3/2)of Nd^(2+)and^(2)F_(5/2)of Yb^(3+)compensated by phonon assistance due to energy gap between these *** efficiency of ET increases with the ytterbium content up to almost 90%for the sample with 1 mol%of Yb2O3,which was evaluated by lifetime ***-conversion photoluminescence by exciting trivalent ions of neodymium(808 nm)and ytterbium(975 nm)is *** observed up-converted emission bands are related to the 4f-4f transitions of Nd^(3+)and the spin-forbidden 5d-4f transition of Yb^(2+).Nd^(3+)upconversion emission is observed under 975 nm excitation,presenting an almost quadratic emission dependence with power excitation,which suggests that two laser photons participate in the up-conversion(UC)process,showing that ET occurs by a phonon-assisted energy transfer and cooperative energy transfer.

关键词： solar cells Energy transfer Glassy systems Rare earths

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Transition from backward to sideward stimulated Raman scattering with broadband lasers in plasmas

引用

Matter and Radiation at Extremes 2023年第6期8卷 63-73页

作者： X.F.Li s.M.Weng P.Gibbon h.h.Ma s.h.Yew Z.Liu Y.Zhao M.Chen Z.M.sheng j.Zhang Key Laboratory for Laser Plasmas(MoE) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFsA Shanghai Jiao Tong UniversityShanghai 200240China Institute for Advanced simulation Jülich Supercomputing CentreForschungszentrum Jülich52425 JülichGermany Centre for Mathematical Plasma Astrophysics Katholieke Universiteit Leuven3000 LeuvenBelgium Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China school of science Shenzhen Campus of Sun Yat-sen UniversityShenzhen 518107China

Broadband lasers have been proposed as future drivers of inertial confined fusion(ICF)to enhance the laser-target coupling efficiency via the mitigation of various parametric *** physical mechanisms involved have been explored recently,but are not yet fully ***,stimulated Raman scattering(sRs)as one of the key parametric instabilities is investigated theoretically and numerically for a broadband laser propagating in homogeneous plasma in multidimensional *** linear sRs growth rate is derived as a function of scattering angles for two monochromatic laser beams with a fixed frequency differenceδω.Ifδω/ω_(0)∼1%,withω0 the laser frequency,these two laser beams may be decoupled in stimulating backward sRs while remaining coupled for sideward sRs at the laser intensities typical for ***,side-scattering may dominate over backward sRs for two-color laser *** finding of sRs transition from backward to sideward sRs is then generalized for a broadband laser with a few-percent ***-in-cell simulations demonstrate that with increasing laser bandwidth,the sideward sRs gradually becomes dominant over the backward *** sideward sRs is very efficient in producing harmful hot electrons,attention needs to be paid on this effect if ultra-broadband lasers are considered as next-generation ICF drivers.

关键词： scattering backward Transition

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于肿瘤生长速率的LI-RADs生长阈值可提高≤3.0 cm肝细胞癌的诊断效能

引用

国际医学放射学杂志 2024年第2期 255-255页

作者： B.jeong s.j.Choi s.h.Choi h.j.jang j.h.Byun h.j.Won 侯唯姝

摘要目的尽管2018版肝脏成像报告和数据系统（LIRADs）对肝脏病变的生长阈值（TG）进行了修订，但确定TG的2次检查之间的适当时间段尚未确定。该研究比较了基于

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Transfer or blockage:Unraveling the interaction between deformation twinning and grain boundary in tantalum under shock loading with molecular dynamics

引用

journal of Materials science & Technology 2023年第25期156卷 118-128页

作者： Z.C.Meng M.M.Yang A.h.Feng s.j.Qu F.Zhao L.Yang j.h.Yao Y.Yang Q.B.Fan h.Wang Interdisciplinary Centre for Additive Manufacturing (ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China school of Materials science and Engineering University of Science and Technology of ChinaShenyang 110016China school of Materials science and Engineering Tongji UniversityShanghai 201804China Academy for Advanced Interdisciplinary studies Southern University of Science and TechnologyShenzhen 518055China National Key Laboratory of science and Technology on Materials Under shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The interaction between{112}deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair misorientation angles(MA)and geometric compatibility factor(m’).Generally,in the coaxial polycrystal,the value of MA determines the occurrence of twin transfer(TT)or twin blockage(TB),i.e.,twin transfer occurs at MA≤29°with twin blockage *** TT,the value of m’affects the selection of twin variants.,i.e.,the twin system with a larger m’is easier to *** morphology of twin pairs is ruler-shaped and lenticular under TT and TB,respectively,with different thickening mechanisms,including grain boundary dislocation emission.

关键词： Plasticity Grain boundary Twin Atomistic simulation Tantalum

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Grain refinement of Mg-alloys by native MgO particles: An overview

引用

journal of Magnesium and Alloys 2022年第11期10卷 2919-2945页

作者： Z.Fan F.Gao Y.Wang s.h.Wang j.B.Patel Brunel Centre for Advanced solidification Technology(BCAsT) Brunel University LondonUxbridgeUB83PHUK

A fine and equiaxed solidification process delivers multidimensional benefits to Mg-alloys, such as improved castability, reduced casting defects, enhanced mechanical properties, increased corrosion resistance and potential for increased recycled contents. Despite extensive research on grain refinement of Mg-alloys in the last few decades, currently, there is no effective grain refiner available for refining Mg-Al alloys, and our current understanding of grain refining mechanisms is not adequate to facilitate the development of effective grain *** the EPsRC(UK) Li ME hub’s research program, substantial advances have been made in understanding the early stages of solidification covering prenucleation, heterogeneous nucleation, grain initiation and grain refinement. In this paper, we provide a comprehensive overview of grain refinement of Mg-alloys by native MgO particles. We show that native MgO particles can be made available for effective grain refinement of Mg-alloys by intensive melt shearing regardless of the alloy compositions. More importantly, we demonstrate that(1) the addition of more potent exogenous particles will not be more effective than native MgO;and(2) MgO particles are difficult to be made more impotent for grain refinement through promoting explosive grain initiation. We suggest that the most effective approach to grain refinement of Mg-alloys is to make more native MgO particles available for grain refinement through dispersion, such as by intensive melt shearing.

关键词： Mg-alloys Grain refinement Magnesia(MgO) Nucleation Grain initiation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：