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A tabletop, ultrashort pulse photoneutron source driven by electrons from laser wakefield acceleration

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matter and Radiation at Extremes 2017年第6期2卷 296-302页

作者： X.J.Jiao J.m.Shaw T.Wang X.m.Wang H.Tsai P.Poth I.Pomerantz L.A.Labun T.Toncian m.C.Downer b.m.hegelich Center for High Energy Density Science University of TexasAustinTX 78712USA Institut fur Kernphysik Technische Universitat DarmstadtGermany The School of Physics and Astronomy Tel-Aviv UniversityTel-Aviv69978Israel

Relativistic electron beams driven by laser wakefield acceleration were utilized to produce ultrashort neutron *** experiment was carried out on the 38 fs,~0.5 J,800 nm Ti:Sapphire laser in the 10 TW UT 3 laser lab at University of Texas at *** target gas was a high density pulsed gas jet composed of 90%He and 10%N *** laser pulse with a peak intensity of 1.5×10^(18) W/cm^(2) interacted with the target to create a cylindrical plasma channel of 60 mm radius(FWHm)and 1.5 mm length(FWHm).Electron beams of~80 pC with the Gaussian energy distribution centered at 37 meV and a width of 30 meV(FWHm)were produced via laser wakefield *** fluences of~2.4×10^(6) per shot with hundreds of ps temporal length were generated through bremsstrahlung and subsequent photoneutron reactions in a 26.6 mm thick tungsten *** were compared with those of simulations using EPOCH and GEANT4,showing agreement in electron spectrum,neutron fluence,neutron angular distribution and conversion rate.

关键词： Neutron source LWFA Photoneutron reaction

Non-maxwellian electron distributions resulting from direct laser acceleration in near-critical plasmas

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matter and Radiation at Extremes 2016年第1期1卷 82-87页

作者： T.Toncian C.Wang E.mcCary A.meadows A.V.Arefiev J.blakeney K.Serratto D.Kuk C.Chester R.Roycroft L.Gao H.Fu X.Q.Yan J.Schreiber I.Pomerantz A.bernstein H.Quevedo G.Dyer T.Ditmire b.m.hegelich Department of Physics University of TexasAustinTX78712USA State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing100871China Fakultat fur Physik Ludwig-Maximilians-UniversityMunichGermany

The irradiation of few-nm-thick targets by a finite-contrast high-intensity short-pulse laser results in a strong pre-expansion of these targets at the arrival time of the main *** targets decompress to near and lower than critical densities with plasmas extending over few micrometers,*** *** interaction of the main pulse with such a highly localized but inhomogeneous target leads to the generation of a short channel and further self-focusing of the laser *** at the Glass Hybrid OPCPA Scaled Test-bed(GHOST)laser system at University of Texas,Austin using such targets measured non-maxwellian,peaked electron distribution with large bunch charge and high electron density in the laser propagation *** results are reproduced in 2D PIC simulations using the EPOCH code,identifying direct laser acceleration(DLA)[1]as the responsible *** is the first time that DLA has been observed to produce peaked spectra as opposed to broad,maxwellian spectra observed in earlier experiments[2].This high-density electrons have potential applications as injector beams for a further wakefield acceleration stage as well as for pump-probe applications.

关键词： Direct laser acceleration Electron acceleration Near critical plasmas PIC simulations

mitochondria–cGAS–STING axis is a potential therapeutic target for senescence-dependent inflammaging-associated neurodegeneration

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Neural Regeneration Research 2025年第3期20卷 805-807页

作者： Josém.Izquierdo Centro de biología molecular Severo Ochoa(Cbm) Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid(CSIC-UAM)MadridSpain

The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of pre... 详细信息

关键词： Latin potential lasting

On a biseparability criterion of bipartite qudit state

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Chinese Physics b 2019年第8期28卷 42-49页

作者： b benzimoun m Daoud LPHE-modeling and Simulation Faculty of SciencesUniversity Mohammed ⅤRabatMorocco Department of Physics Faculty of Sciences-Ain ChockUniversity Hassan ⅡCasablancaMorocco Abdus Salam International Centre for Theoretical Physics TriesteItaly

In this paper,we propose a new approach to tackle the separability problem for bipartite qudit *** is based on the majorana representation which allows to represent a N-spinors(qudit)as a symmetric state of N spin-1/*** also discuss how we can exploit such representation and the notion of the biseparability of multipartite qubit states in the sense to establish new criteria of the separability problem based on the PPT and concurrence.

关键词： separability bipartite qubit state partial separability majorana representation

Phase diagrams and magnetic properties of the mixed spin-1 and spin-3/2 Ising ferromagnetic thin film: monte Carlo treatment

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Chinese Physics b 2019年第2期28卷 414-419页

作者： b boughazi m boughrara m Kerouad Laboratoire Physique des matériaux et modélisation des Systémes(LP2mS) UnitéAssociée au CNRST-URAC:08Faculty of SciencesUniversity Moulay Ismail

Phase diagrams and magnetic properties of the mixed spin-1 and spin-3/2 Ising film with different single-ion anisotropies are investigated, by the use of monte Carlo simulation based on heat bath algorithms. The effects of the crystal-fields and the surface coupling on the phase diagrams are investigated in detail and the obtained phase diagrams are presented. Depending on the Hamiltonian parameters, the system exhibits both second-and first-order phase transitions besides tricritical point, triple point, and isolated critical end point.

关键词： monte Carlo simulation thin film phase diagrams magnetic properties

Strong and ductile mg alloys developed by dislocation engineering

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Journal of materials Science & Technology 2019年第3期35卷 394-395页

作者： m.Wang b.b.He m.X.Huang Department of mechanical Engineering The University of Hong Kong Shenzhen Institute of Research and Innovation The University of Hong Kong

Dislocation engineering concept has been successfully employed to tackle the strength-ductility trade-off in steels, resulting in the development of high-strength high-ductility deformed and partitioned(D&P)steel. The present perspective proposes to employ such dislocation engineering concept to develop strong and ductile magnesium(mg) alloys. High density of dislocations could be generated at appropriate temperature and retained in the mg alloy after quenching to room temperature. Those dislocations inherited from the warm deformation could provide dislocation sources when the mg alloy is deformed at room temperature, resulting in good ductility. The high dislocation density generated at warm deformation provides dislocation forest hardening, leading to improved yield strength of mg alloy.

关键词： Dislocation engineering mg alloys Warm rolling Strength and ductility

Nonlinear continuous bi-inductance electrical line with dissipative elements:Dynamics of the low frequency modulated waves

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Chinese Physics b 2020年第4期29卷 179-189页

作者： S m Ngounou F b Pelap Unite de Recherche de mecanique et de modelisation des Systèmes Physiques(UR-2 mSP) Faculte des SciencesUniversite de DschangBP 69 DschangCameroun Unite de Recherche de matiere Condensee d'Electronique et de Traitement du Signal(UR-mACETS) Faculte des SciencesUniversite de DschangBP 67 DschangCameroun

The dynamics of modulated waves in a nonlinear bi-inductance transmission line with dissipative elements are *** show the existence of two frequency modes and carry out intensive investigations on the low frequency *** to the multiple scales method,the behavior of these waves is investigated and the dissipative effects are *** appears that the dissipation coefficient increases with the carrier wave *** the continuous approximation,we derive that the propagation of these waves is governed by the complex Ginzburg-Landau equation instead of the Korteweg-de-Vries equation as previously *** studies of the dynamics of plane waves in the line reveal the existence of three additional regions in the dispersion curve where the modulational phenomenon is *** the low frequency mode,we demonstrate that the network allows the propagation of dark and bright *** findings are in perfect agreement with the analytical predictions.

关键词： dissipative bi-inductance network low frequency mode continuous approximation complex Ginzburg-Landau equation

Seepage properties of a single rock fracture subjected to triaxial stresses

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Progress in Natural Science:materials International 2007年第12期17卷 1482-1486页

作者： m b Jaksa 5005 Australia School of Civil and Environmental Engineering University of Adelaide

Coupled properties of seepage and stress fields of rock fractures greatly influence the safety of geotechnical engineering work. based on the closing deformation principle of a single rock fracture, equations describing relationships of aperture and triaxial stresses are developed, and coupled models of seepage and triaxial stresses are proposed. Seepage tests are conducted under triaxial stress conditions by adopting hard granite specimens with an artificial fracture. The results show that the normal stress, lateral stress and seepage pressure significantly affect the flow behavior of rock fractures, and that hydraulic conductivity decreases with increasing normal stress, but increases with rising lateral stress or seepage pressure. In addition, an exponential function provides a good representation of the seepage characteristics of a single rock fracture subjected to triaxial stresses.

关键词： triaxial stresses rock fractures seepage hydraulic conductivity coupling model.

Dynamics of high-frequency modulated waves in a nonlinear dissipative continuous bi-inductance network

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Chinese Physics b 2021年第6期30卷 193-205页

作者： S m Ngounou F b Pelap Unitéde Recherche de mécanique et de modélisation des Systèmes Physiques(UR-2 mSP) Facultédes SciencesUniversitéde DschangBP 69 DschangCameroun Unitéde Recherche de matière Condensée d'Electronique et de Traitement du Signal(UR-mACETS) Facultédes SciencesUniversitéde DschangBP 67 DschangCameroun

This paper presents intensive investigation of dynamics of high frequency nonlinear modulated excitations in a damped bimodal lattice. The effects of the dissipation are considered through a linear dissipation coefficient whose evolution in terms of the carrier wave frequency is checked. There appears that the dissipation coefficient increases with the carrier wave frequency. In the linear limit and for high frequency waves, study of the asymptotic behavior of plane waves reveals the existence of two additional regions in the dispersion curve where the modulational phenomenon is observed compared to the lossless line. based on the multiple scales method exploited in the continuum approximation using an appropriate decoupling ansatz for the voltage of the two different cells, it appears that the motion of modulated waves is described by a dissipative complex Ginzburg–Landau equation instead of a Korteweg–de Vries equation. We also show that this amplitude wave equation admits envelope and hole solitons in the high frequency mode. From basic sources, we design a programmable electronic generator of complex signals with desired characteristics, which delivers signals exploited as input waves for all our numerical simulations. These simulations are performed in the LTspice software that uses realistic components and give the results that corroborate perfectly our analytical predictions.

关键词： dissipative bi-inductance network high-frequency mode continuous approximation dissipative complex Ginzburg–Landau equation programmable electronic generator LT-Pspice observations