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

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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

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Bright betatron radiation from direct-laseraccelerated electrons at moderate relativistic laser intensity

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Matter and Radiation at Extremes 2021年第4期6卷 10-17页

作者： O.N.Rosmej x.f.shen A.Pukhov L.Antonelli f.Barbato M.Gyrdymov M.M.Gunther S.Zahter V.S.Popov N.G.Borisenko N.E.Andreev GSI Helmholtzzentrum fur Schwerionenforschung GmbH Planckstraße164291 DarmstadtGermany Goethe University FrankfurtMax-von-Laue-Straße 160438 Frankfurt am MainGermany Helmholtz forschungsakademie Hessen fur fAIR(HfHf) Campus Frankfurt am MainMax-von-Laue-Straße 1260438 Frankfurt am MainGermany Heinrich-Heine-University Dusseldorf Universitatsstraße 1DusseldorfGermany York Plasma Institute University of YorkChurch LaneHeslingtonYork YO105DQUnited Kingdom University of Bordeaux CNRSCEACELIAUMR 5107F-33405 TalenceFrance Joint Institute for High Temperatures RASIzhorskaya St.13Bldg.2125412 MoscowRussia Moscow Institute of Physics and Technology(State University) Institutskiy Pereulok 9141700 DolgoprudnyMoscow RegionRussia P.N.Lebedev Physical Institute RASLeninsky Prospekt 53119991 MoscowRussia

Direct laser acceleration(DLA)of electrons in a plasma of near-critical electron density(NCD)and the associated synchrotron-like radiation are discussed for moderate relativistic laser intensity(normalized laser amplitude a0≤4.3)and ps length *** regime is typical of kJ PW-class laser facilities designed for high-energy-density(HED)*** experiments at the PHELIx facility,it has been demonstrated that interaction of a 1019 W/cm2 sub-ps laser pulse with a sub-mm length NCD plasma results in the generation of high-current well-directed superponderomotive electrons with an effective temperature ten times higher than the ponderomotive potential[Rosmej et al.,Plasma *** fusion 62,115024(2020)].Three-dimensional particle-in-cell simulations provide good agreement with the measured electron energy distribution and are used in the current work to study synchrotron radiation from the DLA-accelerated *** resulting x-ray spectrum with a critical energy of 5 keV reveals an ultrahigh photon number of 731011 in the 1–30 keV photon energy range at the focused laser energy of 20 *** simulations of betatron x-ray phase contrast imaging based on the DLA process for the parameters of a PHELIx laser are *** results are of interest for applications in HED experiments,which require a ps x-ray pulse and a high photon flux.

关键词： intensity relativistic critical

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Rational Solutions of first Order Algebraic Ordinary Differential Equations

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Journal of Systems Science & Complexity 2024年第2期37卷 567-580页

作者： fENG Shuang shen Liyong School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjing 211816China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Let f(t,y,y')=∑ _(i=0)^(n )a_(i)(t,y)y'^(i)=0 be an irreducible first order ordinary differential equation with polynomial *** in 1998 proved that there exists a constant C such that every rational solution of f(t,y,y')=0 is of degree not greater than *** show that this degree bound C depends not only on the degrees of f in t,y,y' but also on the coefficients of f viewed as the polynomial in t,y,y'.In this paper,the authors show that if f satisfies deg(f,y)f,y')or n max i=0{deg(a_(i),y)−2(n−i)}>0,then the degree bound C only depends on the degrees of f in t,y,y',and furthermore we present an explicit expression for C in terms of the degrees of f in t,y,y'.

关键词： Degree bound first order AODE height rational solution

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Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 516-529页

作者： Ting Chen Banglong fu Junjun shen Uceu f.H.R.Suhuddin Björn Wiese Yuanding Huang Min Wang Jorge f.dos Santos Jean Pierre Bergmann Benjamin Klusemann Solid State Materials Processing Institute of Material MechanicsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany functional Magnesium Materials Institute of Metallic BiomaterialsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong UniversityDongchuan Road 800Shanghai 200240China Applied Materials and Manufacturing Energy and Environment DivisionPacific Northwest National LaboratoryPO Box 999RichlandWA 99352USA Production Technology Group Technisiche Universität IlmenauGustav-Kirchhoff-Platz 2Ilmenau 98693Germany Institute for Production Technology and Systems Leuphana University of LüneburgUniversitätsallee 1Lüneburg 21335Germany

In order to obtain Mg alloys with fine microstructures and high mechanical performances,a novel friction-based processing method,name as“constrained friction processing(CfP)”,was *** CfP,defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were *** to the previous as-cast microstructure,the grain size was reduced from more than 1 mm to around 4μm within 3 s by a single process *** compressive yield strength was increased by 350%while the ultimate compressive strength by 53%.According to the established material flow behaviors by“tracer material”,the plastic material was transported by shear *** the base material to the rod,the material experienced three stages,*** by the tool,upward flow with additional tilt,followed by upward *** microstructural evolution was revealed by“stop-action”*** microstructural development at regions adjacent to the rod is mainly controlled by twinning,dynamic recrystallization(DRx)as well as particle stimulated nucleation,while that within the rod is related to DRx combined with grain growth.

关键词： Constrained friction processing Magnesium alloys Microstructure Mechanical properties Grain refinement Plastic deformation

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Recursive filtering for Stochastic Systems With filter-and-forward Successive Relays

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1202-1212页

作者： Hailong Tan Bo shen Qi Li Hongjian Liu School of Mathematics-Physics and finance Anhui Polytechnic UniversityWuhu 241000China Anhui future Technology Research Institute Anhui Polytechnic UniversityWuhu 241000China College of Information Science and Technology Donghua UniversityShanghai 201620China Engineering Research Center of Digitalized Textile and fashion Technology Ministry of EducationShanghai 201620China School of Information Science and Engineering Hangzhou Normal UniversityHangzhou 311121China

In this paper,the recursive filtering problem is considered for stochastic systems over filter-and-forward successive relay(ffSR)*** ffSR is located between the sensor and the remote filter to forward the *** the successive relay,two cooperative relay nodes are adopted to forward the signals alternatively,thereby existing switching characteristics and inter-relay interferences(IRI).Since the filter-and-forward scheme is employed,the signal received by the relay is retransmitted after it passes through a linear *** objective of the paper is to concurrently design optimal recursive filters for ffSR and stochastic systems against switching characteristics and IRI of ***,a uniform measurement model is proposed by analyzing the transmission mechanism of ***,novel filter structures with switching parameters are constructed for both ffSR and stochastic *** the help of the inductive method,filtering error covariances are presented in the form of coupled difference ***,the desired filter gain matrices are further obtained by minimizing the trace of filtering error ***,the stability performance of the filtering algorithm is analyzed where the uniform bound is guaranteed on the filtering error ***,the effectiveness of the proposed filtering method over ffSR is verified by a three-order resistance-inductance-capacitance circuit system.

关键词： filtering successive stochastic

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A Coordinate-free Approach to the Design of Generalized Griffis-Duffy Platforms

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 95-103页

作者： Chengwei shen xu Pei Lubin Hang Jingjun Yu College of Optical Mechanical and Electrical EngineeringZhejiang A&F UniversityHangzhou 311300China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China

Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes *** remaining permanently in a singularity are beneficial for linearto-rotary motion ***-Duffy(GD)platform is a mobile structure admitting a Bricard *** this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed *** generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same *** to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD ***,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis.

关键词： Generalized Griffis-Duffy platforms Self-motion Inversion Coordinate-free determination Manipulator design

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An mmWave Dual-Band Integrated Substrate Gap Waveguide Single Cavity filter with frequency Selectivity

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China Communications 2024年第1期21卷 188-199页

作者： Qiuhua Lin Dongya shen Lihui Wang Zhiyong Luo School of Electronics and Communication Engineering Sun Yat-sen UniversityShenzhen 518107China School of Information Science and Engineering Yunnan UniversityKunming 650091China Pengcheng Laboratory Shenzhen 518107China shenzhen Key Laboratory of Navigation and Communication Integration Shenzhen 518107China

A novel dual-band ISGW cavity filter with enhanced frequency selectivity is proposed in this paper by utilizing a multi-mode coupling *** cavity is designed to control the number of modes,and then the ports are determined by analyzing the coupling relationship between these selected *** synthesizing the coupling matrix of the filter,a nonresonating node(NRN)structure is introduced to flexibly tune the frequency of modes,which gets a dualband and quad-band filtering response from a tri-band filter no the ***,a frequency selective surface(fSS)has been newly designed as the upper surface of the cavity,which significantly improves the bad out-of-band suppression and frequency selectivity that often exists in most traditional cavity filter designs and *** results show that its two center frequencies are f01=27.50 GHz and f02=32.92GHz,*** with the dual-band filter that there is no the fSS metasurface,the out-of-band suppression level is improved from measured 5 dB to18 dB,and its finite transmission zero(fTZ)numbers is increased from measured 1 to 4 between the two designed *** with the tri-band and quadband filter,its passband bandwidth is expanded from measured 1.17%,1.14%,and 1.13% or 1.31%,1.50%,0.56%,and 0.57% to 1.71% and 1.87%.In addition,the filter has compact,small,and lightweight characteristics.

关键词： coupling topology frequency selectivity non-resonating node(NRN) out-of-band suppression single ISGW cavity filter

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Corrosion behavior and protection mechanism of carbon steel coated with ethylene chlorotrifluoroethylene(ECTfE)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 502-515页

作者： Peihu shen Jun WEN Biqin DONG Hedong LI Minjia WANG School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou310018China College of Civil and Transportation Engineering Shenzhen UniversityShenzhen518061China Zhejiang Research Institute of Chemical Industry Co. Ltd.Hangzhou310023China

Ethylene chlorotrifluoroethylene(ECTfE)coating was applied to the surface of carbon steel through electrostatic spraying and low-temperature heat *** morphology and structure of the coating were analyzed using various characterization *** electrochemical data of the coated steel soaked in 3.5%(mass fraction)NaCl solution for 90 d at different periods were also *** findings indicate that the outer surface of the coating remains structurally stable before and after soaking.f can diffuse into the steel substrate,facilitating the bonding between the coating and the steel substrate,but the free f also induces a weakening effect on the crystalline *** to the thickness of the coating edge and the susceptibility to infiltration of the corrosive medium,under-film micro-zone corrosion occurs at a slow *** soaking for 90 d,the impedance modulus measures approximately 10^(4)Ω·cm^(2),and the open circuit potential(OCP)is−0.61 *** self-corrosion current density is 1.13×10^(−6)A/cm^(2),resulting in a calculated coating protection rate of 99.29%.In summary,despite edge corrosion occurring,the ECTfE coating provides excellent corrosion protection.

关键词： Coating fluorine resin Edge corrosion Corrosive behavior Electrochemical performance

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Pd-Catalyzed Highly Regioselective Hydroesterification of Terminal Alkyl Olefins with formates

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Chinese Journal of Chemistry 2024年第12期42卷 1381-1386页

作者： Junhua Li Tianci shen Yan Yang Yian Shi Jiangsu Key Laboratory of Advanced Catalytic Materials&Technology Schoolof Petrochemical EngineeringInstitute of Natural and Synthetic Organic ChemistryChangzhou UniversityChangzhouJiangsu 213164China

Comprehensive Summary A Pd-catalyzed regioselective hydroesterification of alkyl terminal olefins with aryl formates is described.A wide variety of linear carboxylic esters bearing various functional groups can be obtained in good yields with high regioselectivities under mild reaction conditions by using 1,2-DTBPMB or(p-f-Ph)3P as *** reaction process is operationally simple and requires no handling of toxic CO or strong *** resulting aryl esters can be readily converted to other carboxylic acid derivatives.

关键词： Alkenes Regioselectivity Carbonylation Hydroesterification formates

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Linear-fitting-based recursive filtering for nonlinear systems under encoding-decoding mechanism

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Science China(Information Sciences) 2024年第5期67卷 183-196页

作者： Bo JIANG Hongli DONG Zhiwei GAO Yuxuan shen fan YANG Artificial Intelligence Energy Research Institute Northeast Petroleum University Heilongjiang Provincial Key Laboratory of Networking and Intelligent Control Sanya Offshore Oil & Gas Research Institute Northeast Petroleum University School of Electrical & Information Engineering Northeast Petroleum University

This paper deals with a recursive filtering problem for a class of discrete time-varying nonlinear networked systems with the encoding-decoding mechanism. The linear fitting method is introduced to handle the nonlinearity. An encoding-decoding mechanism is constructed to describe the data transmission process in wireless communication networks(WCNs). To be specific, the measurement outputs are mapped by a quantizer to unique codewords for transmission in WCNs. Then, the codewords are decoded by the decoder to recover the measurement outputs which are sent to the filter. The processing/encoding delay and network delay have been considered. firstly, on the premise that the upper bound of the filtering error covariance is minimum, the appropriate filtering gain is calculated. Then, the mean square exponential boundedness of the filtering error is analyzed. finally, two simulation examples are presented to verify the effectiveness of the proposed algorithm.

关键词： encoding-decoding mechanism uniform quantizer linear fitting networked systems recursive filtering

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