检索结果-南通市图书馆

Laser processing effects on Ti−45Nb alloy surface,corrosive and biocompatible properties

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous metals Society of China 2024年第8期34卷 2533-2551页

作者： I.CVIjOVIĆ-ALAGIĆ S.LAKETIĆ m.mOmČILOVIĆ j.CIGANOVIĆ Đ.VELjOVIĆ j.BAjAT V.KOjIĆ m.RAKIN Vinča Institute of Nuclear Sciences-National Institute of the Republic of Serbia University of BelgradeP.O.Box 52211001 BelgradeSerbia Faculty of Technology and metallurgy University of BelgradeKarnegijeva 411120 BelgradeSerbia Oncology Institute of Vojvodina Faculty of MedicineUniversity of Novi SadPut Dr Goldmana 421204 Sremska KamenicaSerbia

The Ti−45Nb(wt.%)alloy properties were investigated in relation to its potential biomedical *** surface modification was utilized to improve its performance in biological *** a result of the laser treatment,(Ti,Nb)O scale was formed and various morphological features appeared on the alloy *** electrochemical behavior of Ti−45Nb alloy in simulated body conditions was evaluated and showed that the alloy was highly resistant to corrosion deterioration regardless of additional laser surface modification ***,the improved corrosion resistance after laser treatment was evident(the corrosion current density of the alloy before laser irradiation was 2.84×10^(−8)A/cm^(2),while that after laser treatment with 5 mj was 0.65×10^(−8)A/cm^(2))and ascribed to the rapid formation of a complex and passivating bi-modal surface oxide *** cytotoxicity and effects of the Ti−45Nb alloy laser surface modification on the mRC-5 cell viability,morphology,and proliferation were also *** Ti−45Nb alloy showed no cytotoxic ***,cells showed improved viability and adherence to the alloy surface after the laser irradiation *** highest average cell viability of 115.37%was attained for the alloy laser-irradiated with 15 *** showed that the laser surface modification can be successfully utilized to significantly improve alloy performance in a biological environment.

关键词： Ti−45Nb alloy laser surface scanning electrochemical properties biocompatibility cell morphology

同方期刊数据库

miniSCIDOm: a scintillator-based tomograph for volumetric dose reconstruction of single laser-driven proton bunches

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2024年第2期12卷 41-50页

作者： A.Corvino m.Reimold E.Beyreuther F.-E.Brack F.Kroll j.Pawelke j.D.Schilz m.Schneider U.Schramm m.E.P.Umlandt K.Zeil T.Ziegler j.m..zkes-Ng Helmholtz-Zentrum Dresden–Rossendorf DresdenGermany Technische Universität Dresden DresdenGermany OncoRay–National Center for Radiation Research in Oncology Faculty of Medicine and University Hospital Carl Gustav CarusTUD Dresden University of TechnologyHelmholtz-Zentrum Dresden–RossendorfDresdenGermany Current affiliation:Institut Curie UniversitéPSLCNRS UMR3347OrsayFrance Current affiliation:Universitätsklinikum Freiburg FreiburgGermany

Laser plasma accelerators(LPAs)enable the generation of intense and short proton bunches on a micrometre scale,thus offering new experimental capabilities to research fields such as ultra-high dose rate radiobiology or material *** spectrally broadband,laser-accelerated proton bunches allow for tailored volumetric dose deposition in a sample via single bunches to excite or probe specific sample *** rising number of such experiments indicates a need for diagnostics providing spatially resolved characterization of dose distributions with volumes of approximately 1 cm^(3) for single proton bunches to allow for fast online *** we present the scintillator-based miniSCIDOm detector for online single-bunch tomographic reconstruction of dose distributions in volumes of up to approximately 1 cm^(3).The detector achieves a spatial resolution below 500μm and a sensitivity of 100 *** detector performance is tested at a proton therapy cyclotron and an LPA proton *** experiments’primary focus is the characterization of the scintillator’s ionization quenching behaviour.

关键词： beam monitoring detectors laser-driven proton beams scintillator-based diagnostics ultra-high dose rate

在线全文

学校读者我要写书评

暂无评论

丈量宇宙最强力

环球科学 2024年第11期 24-31页

作者：斯坦利·j.布罗德斯基亚历山大·德尔克雷格·D.罗伯茨李新鹏(翻译) 崔钫(审校) 美国斯坦福大学SLAC国家加速器实验室美国弗吉尼亚州纽波特纽斯市托马斯·杰斐逊(Thomas jefferson)国家加速器设施南京大学物理学院

宇宙中最强之力,也恰巧被称作强力。我们从来没有亲眼见证过它强大的力量,因为这种力仅作用在亚原子尺度。在这一尺度下,强力会将质子和中子中的夸克束缚在一起,然后将这些核子结合成原子核。宇宙中迄今为止已知的四种基本力是引力、电... 详细信息

宇宙中最强之力,也恰巧被称作强力。我们从来没有亲眼见证过它强大的力量,因为这种力仅作用在亚原子尺度。在这一尺度下,强力会将质子和中子中的夸克束缚在一起,然后将这些核子结合成原子核。宇宙中迄今为止已知的四种基本力是引力、电磁力、弱力和强力,其中强力是最强的——它是引力的100万亿万亿万亿(1038)倍。但与此同时,它也是我们现在所知最少的基本力。

关键词：亚原子引力夸克电磁力弱力原子核强力宇宙

measurement,associations,patterns,and promotion:Unveiling vital areas in physical activity epidemiology

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

journal of Sport and Health Science 2024年第5期13卷 605-607页

作者： Kara m.Whitaker Guest editor michael j.Lamonte Department of Health&Human Physiology University of IowaIowa CityIA 52242USA Department of Epidemiology and Environmental Health University of BuffaloBuffaloNY 14214 USA

Physical activity(PA)epidemiology first emerged as a new field of study around the 1950s with publication of seminal investigations on London civil servants1 and has continued to evolve as a scientific discipline to present *** subdiscipline of epidemiology studies the frequencies,distributions,and dynamics of PA and its impact on human health,morbidity,and *** over the past 75 years has demonstrated numerous health benefits of *** on these research findings,the World Health Organization recommends adults aged 18-64 years engage in at least 150-300 min of moderate-intensity aerobic PA per week,or at least 75-150 min of vigorous-intensity aerobic PA per week,or a combination of both intensities.

关键词： epidemiology promotion continued

Characterization of bright betatron radiation generated by direct laser acceleration of electrons in plasma of near critical density

在线全文

学校读者我要写书评

暂无评论

matter and Radiation at Extremes 2024年第2期9卷 26-35页

作者： j.Cikhardt m.Gyrdymov S.Zähter P.Tavana m.m.Günther N.Bukharskii N.Borisenko j.jacoby X.F.Shen A.Pukhov N.E.Andreev O.N.Rosmej Faculty of Electrical Engineering Czech Technical University in Prague16627 Prague 6Czech Republic Goethe University FrankfurtMax-von-Laue-Straße 160438 Frankfurt am MainGermany GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 164291 DarmstadtGermany Focused Energy GmbH Im Tiefen See 4564293 DarmstadtGermany National Research Nuclear University mEPhI Kashirskoe shosse 31115409 MoscowRussian Federation Lebedev Physical Institute RAS Leninskiy Prospekt 53119991 MoscowRussian Federation Heinrich-Heine-University Düsseldorf Universitätsstrasse 1DüsseldorfGermany joint Institute for High Temperatures RASIzhorskaya st.13Bldg.2125412 MoscowRussian Federation moscow Institute of Physics and Technology Institutskiy Pereulok 9141700 DolgoprudnyRussia

Directed x-rays produced in the interaction of sub-picosecond laser pulses of moderate relativistic intensity with plasma of near-critical density are investigated. Synchrotron-like (betatron) radiation occurs in the process of direct laser acceleration (DLA) of electrons in a relativisticlaser channel when the electrons undergo transverse betatron oscillations in self-generated quasi-static electric and magnetic fields. In anexperiment at the PHELIX laser system, high-current directed beams of DLA electrons with a mean energy ten times higher than the ponderomotive potential and maximum energy up to 100 meV were measured at 10^(19) W/cm^(2)laser intensity. The spectrum of directed x-raysin the range of 5–60 keV was evaluated using two sets of Ross filters placed at 0°and 10°to the laser pulse propagation axis. The differential x-ray absorption method allowed for absolute measurements of the angular-dependent photon fluence. We report 10^(13) photons/sr withenergies >5 keV measured at 0°to the laser axis and a brilliance of 10^(21) photons s^(−1) mm^(−2) mrad−2(0.1%BW)−1. The angular distributionof the emission has an FWHm of 14°–16°. Thanks to the ultra-high photon fluence, point-like radiation source, and ultra-short emissiontime, DLA-based keV backlighters are promising for various applications in high-energy-density research with kilojoule petawatt-class laserfacilities.

关键词： laser acceleration critical

粉末冶金Al-5.6Zn-2mg合金在热压缩过程中加工硬化特性及本构模型的比较

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

journal of Central South University 2024年第2期31卷 346-368页

作者： KATIKA Harikrishna DAmODA R.K. DAVIDSON m.j. SEETHARAm R. KASAGANI Veera Venkata Nagaraju Department of mechanical Engineering National Institute of TechnologyWarangal 506004India Department of mechanical Engineering The Indian Institute of Information Technology Design and ManufacturingKurnool 518007India

在300~5000℃、应变速率为0.1~0.0001 s−1的条件下,在万能试验机上对Al-5.6Zn-2mg铝合金进行热压缩试验,以确定动态再结晶开始时的加工硬化速率曲线σ_(c)(ε_(c))l以及关键特征σ_(c)(ε_(c))l、σ_(p)(ε_(p))和σ_(ss)与Z系数之间的... 详细信息

在300~5000℃、应变速率为0.1~0.0001 s−1的条件下,在万能试验机上对Al-5.6Zn-2mg铝合金进行热压缩试验,以确定动态再结晶开始时的加工硬化速率曲线σ_(c)(ε_(c))l以及关键特征σ_(c)(ε_(c))l、σ_(p)(ε_(p))和σ_(ss)与Z系数之间的相关性。使用了四个本构模型,Arrhenius模型、改进的johnson-Cook模型(mjC)、改进的Zerilli-Armstrong模型(mZA)和开发的人工神经网络(ANN)。结果表明,ANN型模型和Arrhenius模型的相对误差的绝对平均值最低,分别为0.486%和3.36%,mZA型模型和mjC型模型的相对误差的绝对平均值较高,分别为8.84%和3.93%。由于Arrhenius模型能够处理各种因素之间的非线性关系,因此它被认为是最合适的预测模型,但在材料性质未知或实验数据有限的情况下,mjC模型可能是一种更简单的替代方法。mZA模型不适合估计热压缩时的流变应力。此外,训练最好的神经网络模型的预测性能最好,相对误差的绝对平均值为0.486%,R值为0.99。

关键词：加工硬化速率曲线本构建模热压缩 EBSD分析流变曲线

Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.j.m..mOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

A multi-shot target wheel assembly for high-repetition-rate, laser-driven proton acceleration

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2024年第2期12卷 87-94页

作者： j.Penas A.Bembibre D.Cortina-Gil L.martin A.Reija C.Ruiz m.Seimetz A.Alejo j.Benlliure Instituto Galego de Fisica de Altas Enerxias Universidade de Santiago de CompostelaSantiago de CompostelaSpain Laboratorio Laser de Aceleracion y Aplicaciones RIAIDTUniversidade de Santiago de CompostelaSantiago de CompostelaSpain Instituto Universitario de Física Fundamental y matematicas y Dpto.de Didactica de la matematica y de las Ciencias Experimentales Universidad de SalamancaSalamancaSpain Instituto de Instrumentación para Imagen molecular(I3m) CSIC-Universitat Politecnica de ValenciaValenciaSpain

A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are *** assembly is based on a multi-target rotating wheel capable of hosting more than 5000 targets,mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser *** automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target,which alongside the purpose-built design of the target wheel,enables operation at rates up to 10 *** and continuous laser-driven proton acceleration at 10 Hz is demonstrated,with observed cut-off energy stability about 15%.

关键词： high repetition rate laser-plasma acceleration multi-shot operation proton source target assembly