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Ultrafast Stretched-Pulse Fiber Laser Mode-Locked by Carbon Nanotubes

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Nano Research 2010年第6期3卷 404-411页

作者： Zhipei Sun Tawfique hasan Fengqiu Wang Aleksey G.Rozhin ian h.white Andrea C.Ferrari Department of Engineering University of CambridgeCambridge CB30FAUK

Ultrafast fiber sources having short pulses, broad bandwidth, high energy, and low amplitude fluctuations have widespread applications. Stretched-pulse fiber lasers, incorporating segments of normal and anomalous dispersion fibers, are a preferred means to generate such pulses. We realize a stretched-pulse fiber laser based on a nanotube saturable absorber, with 113 fs pulses, 33.5 nm spectral width and ~0.07% amplitude fluctuation, outperforming current nanotube-based designs.

关键词： Nanotubes fiber laser saturable absorber ultrafast pulse generation

Flexible optoelectronic devices based on metal halide perovskites

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Nano Research 2020年第8期13卷 1997-2018页

作者： hao Chen hao Wang Jiang Wu Feng Wang Ting Zhang Yafei Wang Detao Liu Shibin Li Richard V.Penty ian h.white School of Optoelectronic Information University of Electronic Science and Technology of ChinaChengdu610054China Centre for Advanced Photonics and Electronics University of CambridgeCambridgeCB30FAUK Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu610054China Beijing Key Laboratory for Theory and Technology of Advanced Battery Materials Department of Materials Science and EngineeringPeking UniversityBeijing100871China

The unique physical and chemical properties of metal halide perovskites predestine the devices to achieve high performance in optoelectronic *** the numerous high qualities of perovskites,their different low-temperature synthesis methods and preparation processes make them impressive and popular materials for flexible optoelectronic *** perovskite devices,for instance,solar cells,photodetectors and light-emitting diodes,have been fabricated on flexible substrates and show outstanding flexibility as well as high *** soft wearable electronic systems,mechanical flexibility is the premier *** to common devices based on rigid substrates,flexible perovskite devices are more practical and see widespread applications in energy,detection,display,and other *** review summarizes the recent progress of flexible perovskite solar cells,photodetectors and light-emitting *** design and fabrication of different high-performance flexible perovskite devices are *** low-dimensional perovskite materials and configurations for flexible perovskite devices are *** addition,the limitations and challenges for further application are also briefly discussed.

关键词： perovskite optoelectronic devices flexibility high-performance

Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LED

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Photonics Research 2017年第2期5卷 35-43页

作者： MOhAMED SUFYAN ISLIM RICARDO X.FERREIRA XianGYU hE ENYUAN XIE STEFAN VIDEV ShAUN VIOLA SCOTT WATSON NIKOLAOS BAMIEDAKIS RIChARD V.PENTY ian h.white ANThONY E.KELLY ERDAN GU hARALD hAAS MARTIN D.DAWSON Li–Fi R&D Centre the University of Edinburgh Institute for Digital Communications Institute of Photonics Department of Physics University of Strathclyde Institute for Digital Communications Li–Fi R&D Centre the University of Edinburgh School of Engineering University of Glasgow Centre for Advanced Photonics and Electronics Electrical Engineering Division Department of Engineering University of Cambridge

Visible light communication(VLC)is a promising solution to the increasing demands for wireless *** nitride micro-sized light emitting diodes(micro-LEDs)are strong candidates for VLC due to their high *** violet micro-LEDs are reported in this work with electrical-to-optical bandwidths up to 655 *** orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated,and a data transmission rate of 11.95 Gb/s is achieved with a violet micro-LED,when the nonlinear distortion of the micro-LED is the dominant noise source of the VLC system.A record 7.91 Gb/s data transmission rate is reported below the forward error correction threshold using a single pixel of the segmented array when all the noise sources of the VLC system are present.

关键词： Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LED VLC OFDM LEDs

Public health importance of light intensity physical activity

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Journal of Sport and health Science 2024年第5期13卷 674-675页

作者： Robert Ross ian Janssen Mark S.Tremblay School of Kinesiology and health Studies Queen’s UniversityKingstonON K7L 3N6Canada School of Medicine Division of Endocrinology and MetabolismQueen’s UniversityKingstonON K7L 3N6Canada healthy Active Living and Obesity Research Group Children’s Hospital of Eastern Ontario Research InstituteOttawaON K1H 8L1Canada Department of Pediatrics University of OttawaOttawaON K1H 8L1Canada

*** intensity physical activity(PA)benefits health PA guidelines worldwide recommend that adults accumulate 150 min of moderate intensity or 75 min of vigorous intensity PA(moderate-to-vigorous PA(MVPA))weekly to achieve health benefits.1-3 Absent from these guidelines are recommendations for light intensity PA(LPA,e.g.,walking at a leisurely pace of 3 km/h or less,equivalent to 1.5-2.9 metabolic equivalents).

关键词： intensity light benefits

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)

Convexification of hybrid AC-DC Optimal Power Flow with Line-Commutated Converters

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 617-628页

作者： hongyuan Liang Zhigang Li J.h.Zheng Q.h.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

Line-commutated converter (LCC)-based high-voltage DC (hVDC) systems have been integrated with bulk AC power grids for interregional transmission of renewable power. The nonlinear LCC model brings additional nonconvexity to optimal power flow (OPF) of hybrid AC-DC power grids. A convexification method for the LCC station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical LCC station models that facilitates second-order cone convex relaxation for the OPF of LCC-based AC-DC power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed LCC station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. Simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： AC-DC power system convex relaxation linecommutated converter optimal power flow second-order cone programming

Shell-model representations of the microscopic version of the Bohr–Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 81-92页

作者： h G Ganev Joint Institute for Nuclear Research Dubna Russia Institute of Mechanics Bulgarian Academy of Sciences

The structure of the irreducible collective spaces of the group Sp（12, R）, which many-particle nuclear states are classified according to the chain Sp（12, R） ? U（6） ? SO（6） ? SUpn（3） ■SO（2） ? SO（3） of the proton–neutron symplectic model（PNSM）, is considered in detail. This chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr–Mottelson collective model. The construction of the relevant shell-model representations of the Sp（12, R） group along this chain is considered for three nuclei with varying collective properties and from different mass regions. It is shown that the SUpn（3） basis states of the Sp（12, R） representations belonging to the SO（6） irreps with seniority υ ≥ υ0, with υ0denoting the maximal seniority SO（6） irrep contained in the Sp（12, R） bandhead, are always Pauli allowed, but organized in a different way into different SO（6） shells. This is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm operation. Although the SUpn（3） multiplets within υ hem. The results obtained in the present work are important for the practical application of the microscopic version of the Bohr–Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model shell-model representations Sp(12, R) dynamical algebra

holographic dark energy in non-conserved gravity theory

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Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： h R Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

Recently, reconsidering the Rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~h^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

Marinoan glaciation in the Indian subcontinent——Anatomy and global implications

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Journal of Palaeogeography 2024年第2期13卷 293-308页

作者： h.N.Bhattacharya Department of Earth Sciences Techno India UniversityWest BengalSector VSalt LakeKolkata700091India

Detailed sedimentological analysis of the Pokaran Boulder Bed,representing the most basal unit of the Neoproterozoic-Lower Cambrian Marwar Supergroup,clearly indicates its glacial *** glacial sediments are interpreted as an ice-contact submarine fan *** on the detrital and inherited zircon population of the Marwar Supergroup sediments and interlayered pyroclastic deposits,a Marinoan cryochron of the Cryogenian Period is envisaged for the Pokaran Boulder *** well-preserved Ediacaran elements in the post-glacial sedimentary succession also support a Cryogenian to Early Cambrian age of the Marwar *** glacial deposition at the base of the Marwar Supergroup strengthens the regional correlation between the studied sediments with the Lesser himalayan Blaini-Krol-Tal sediments and the haqf Supergroup of *** available zircon ages and paleomagnetic data of the Malani Igneous suite,along with the Marinoan glacial deposits,detrital zircon ages,and Ediacaran fossil elements of the Marwar Supergroup add significant information to the Neoproterozoic Earth history.

关键词： Neoproterozoic Marinoan glaciation Diamictites Pokaran Boulder Bed Marwar Supergroup