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Facile synthesis of samarium and cerium doped double perovskite cobaltite with enhanced dielectric response

Journal of Rare Earths 2024年第7期42卷 1317-1327页

作者： Yasir Abbas M.Kamran M.Anis-ur-Rehman applied Thermal physics Laboratory Department of PhysicsCOMSATS University Islamabad

The investigation of Sm-Ce doping on structure,conduction,and dielectric response of Bi2Ca2-2xSmxCexCoO6（x=0.000,0.025,0.050,0.075）(BCSCCO) are presented.All the specimens were synthesized by a facile synthesis technique named the co-precipitation route.X-ray diffraction（XRD）reveals that BCSCCO crystallizes into one phase with space group P21/m.The crystallite size,dislocation density,lattice parameters,lattice strain,unit cell volume,and bulk density were determined using XRD data.The structural properties of Bi2Ca2CoO6were examined using calculations based on the density functional theory.Theoretical and experimental values discrepancy is less than 1%.A scanning electron microscope was used for performing a micro structural analysis.The SEM images demonstrate the homogeneous distribution of grains with a range of sizes（0.054-0.090 μm）.The alternating current（ac）conductivity, dielectric permittivity,and tangent loss were also studied as a function of frequency（20 Hz-3 MHz） at different temperatures（100-500℃）.All synthesized samples were examined using nonlinear Debye's function to determine their spreading factor and relaxation time.The specimen with the lowest crystallite size（～23 nm） exhibits a high dielectric permittivity（～3.80×10～6）.The conduction mechanism was examined in the studied samples with the use of Jonscher's power law.The power law indicates that the BCSCCO（x=0.000,0.025） follows correlated barrier hopping,whereas the x=0.050and 0.075 compositions follow non-overlapping polaron tunneling.The studied specimen Bi2Ca1.90Sm0.050Ce0.050CoO6with the highest density（～5.65 g/cm3） displays a high electrical conductivity（-46.1 S/cm）.These findings correspond to those published for ceramics made from calcium cobaltite using solid-state reactions（5.0-26.0 S/cm）.

关键词： Bismuth calcium samarium cerium cobaltite (BCSCCO) Conduction mechanism Rare earths Spreading factor

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amplitude modulation;high-frequency modulation;autoresonance;ion acoustic wave

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High Power Laser Science and Engineering 2024年第1期12卷 74-83页

作者： Michael Valdman Amir Hen Gilad Marcus applied physics Institute Hebrew University of JerusalemJerusalemIsrael

The generation and control of large amplitude plasma gratings and other plasma structures is of paramount importance for the realization of plasma photonics. Autoresonant excitation of such structures by means of chirped amplitude-modulated lasers has been recently discussed and analyzed theoretically. Here we discuss the parameter space for the realization of such a scheme and describe the laser system that was built towards this goal. We also expand our earlier theoretical study to account for the more realistic case of a moderately focused laser beam, instead of the simplified plane wave approximation.

关键词： amplitude modulation high-frequency modulation autoresonance ion acoustic wave

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A Composite Ansatz for Calculation of Dynamical Structure Factor

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Chinese physics Letters 2024年第1期41卷 92-103页

作者：张玉佩莫崇杰张平康炜 HEDPS Center for Applied Physics and Technologyand School of PhysicsPeking UniversityBeijing 100871China Beijing Computational Science Research Center Beijing 100193China Institute of applied physics and Computational Mathematics Beijing 100088China HEDPS Center for Applied Physics and Technologyand College of EngineeringPeking UniversityBeijing 100871China

We propose an ansatz without adjustable parameters for the calculation of a dynamical structure factor.The ansatz combines the quasi-particle Green’s function,especially the contribution from the renormalization factor,and the exchange-correlation kernel from time-dependent density functional theory together,verified for typical metals and semiconductors from a plasmon excitation regime to the Compton scattering regime.It has the capability to reconcile both small-angle and large-angle inelastic x-ray scattering(IXS)signals with muchimproved accuracy,which can be used as the theoretical base model,in inversely inferring electronic structures of condensed matter from IXS experimental signals directly.It may also be used to diagnose thermal parameters,such as temperature and density,of dense plasmas in x-ray Thomson scattering experiments.

关键词： excitation inverse verified

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Nonlinear interaction of head-on solitary waves in integrable and nonintegrable systems

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Chinese physics B 2024年第5期33卷 480-487页

作者：张树甜刘世鲲矫滕菲孙敏胡凤兰黄德财 Department of applied physics Nanjing University of Science and TechnologyNanjing 210094China

This study numerically investigates the nonlinear interaction of head-on solitary waves in a granular chain(a nonintegrable system)and compares the simulation results with the theoretical results in fluid(an integrable system).Three stages(the pre-in-phase traveling stage,the central-collision stage,and the post-in-phase traveling stage)are identified to describe the nonlinear interaction processes in the granular chain.The nonlinear scattering effect occurs in the central-collision stage,which decreases the amplitude of the incident solitary waves.Compared with the leading-time phase in the incident and separation collision processes,the lagging-time phase in the separation collision process is smaller.This asymmetrical nonlinear collision results in an occurrence of leading phase shifts of time and space in the post-in-phase traveling stage.We next find that the solitary wave amplitude does not influence the immediate space-phase shift in the granular chain.The space-phase shift of the post-in-phase traveling stage is only determined by the measurement position rather than the wave amplitude.The results are reversed in the fluid.An increase in solitary wave amplitude leads to decreased attachment,detachment,and residence times for granular chains and fluid.For the immediate time-phase shift,leading and lagging phenomena appear in the granular chain and the fluid,respectively.These results offer new knowledge for designing mechanical metamaterials and energy-mitigating systems.

关键词： integrable system nonintegrable system granular chain solitary wave

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Electron beams probe quantum coherence

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Light(Science & Applications) 2024年第4期13卷 596-597页

作者： Nahid Talebi Institute for Experimental and applied physics Kiel University24118 KielGermany

Scientists have traditionally employed superimposed mutually-coherent electron beams for holography and phase retrieval of electron wavepackets.However,recent theoretical exploration delves into the interaction of superposed electron beams with the matter.This investigation aims to elucidate long-range Coulomb correlations and quantum decoherence phenomena when electrons interact with their environment.

关键词： quantum mutually Electron

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Digital signal acquisition system for complex nuclear reaction experiments

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Nuclear Science and Techniques 2024年第1期35卷 124-133页

作者： Wei-Liang Pu Yan-Lin Ye Jian-Ling Lou Jia-Hao Chen School of physics and State Key Laboratory of Nuclear physics and Technology Peking UniversityBeijing 100871China Institute of applied physics and Computational Mathematics Beijing 100094China

A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data.

关键词： Digital signal acquisition system Trigger Programmable logic Timestamp

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Efficient second and third harmonic generation in dual-layer lithium niobate microdisk resonator

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Science China(physics,Mechanics & Astronomy) 2024年第5期67卷 33-38页

作者： Zhenzhong Hao Xiao Wu Qiang Luo Zhang Li Rui Ma Fang Bo Feng Gao Guoquan Zhang Jingjun Xu MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai UniversityTianjin 300457China

Lithium niobate thin film frequency doubler has extensive applications in the preparation of classical and quantum sources.In this study,we successfully fabricated microdisk resonators with a quality factor of 2.2×10^(5) in reverse-polarization dual-layer x-cut lithium niobate for the first time.Based on the modal phase matching condition,efficient second harmonic generation with a record normalized conversion efficiency of~56000%W-1 and cascaded third harmonic generation with an efficiency of~6500%W-2 were obtained in the microdisk resonator.Compared with the periodically poled lithium niobate microcavity,the complex domain structure preparation processes are avoided.Our work provides a scheme for achieving highly efficient second-order nonlinear effects in non-periodically poled microcavities.

关键词： harmonic lithium niobate

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Experimental observation of the significant difference between surface and bulk Kondo processes in Kondo lattice YbCu_(2)Si_(2)

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Science China(physics,Mechanics & Astronomy) 2024年第4期67卷 154-160页

作者： Yin-Zou Zhao Jiao-Jiao Song Qi-Yi Wu Hao Liu Chen Zhang Bo Chen Hong-Yi Zhang Zhen-Hua Chen Yao-Bo Huang Xue-Qing Ye Ya-Hua Yuan Yu-Xia Duan Jun He Jian-Qiao Meng School of physics Central South UniversityChangsha 410083China Shanghai Institute of applied physics Chinese Academy of SciencesShanghai 201204China

Synchrotron-based angle-resolved photoemission spectroscopy was employed to investigate the temperature evolution of the Yb 4 f spectral for surface and bulk in the Kondo lattice YbCu_(2)Si_(2).Our study quantitatively distinguishes between the surface and bulk hybridization processes,revealing that the onset temperatures for both surface and bulk hybridization processes are significantly higher than the Kondo temperature.Additionally,we found that the effective surface Kondo temperature is much lower than that of the bulk.These findings offer valuable insights into the understanding of heavy fermion physics.

关键词： Kondo lattice angle-resolved photoemission spectroscopy electronic structure hybridization surface state

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Emerging direct current triboelectric nanogenerator for high-entropy mechanical energy harvesting

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Science China(Technological Sciences) 2024年第5期67卷 1297-1316页

作者： CHEN Jie GUO RuiLong GUO HengYu College of physics and Electronic Engineering Chongqing Normal UniversityChongqing 401331China Department of applied physics Chongqing UniversityChongqing 401331China

In the era of the Internet of Things(IoT),the provision of sustainable power to distributed,mobile,and low-power-consumption electronic devices is a critical challenge.To overcome this challenge,the triboelectric nanogenerator(TENG),a highly efficient high-entropy mechanical energy harvesting device,was developed in 2012.This device enables the direct conversion of irregular and low-frequency mechanical energy into pulsed alternating current(AC)signals.However,the incompatibility of most electronic devices with AC signals necessitates rectifier circuits or generators that deliver direct current(DC)signals.In recent years,DC-TENGs have undergone extensive development,achieving significant milestones in various application fields while also facing crucial challenges that require solutions.In this review,three categories of DC-TENG devices with distinct operating mechanisms are comprehensively explored:multiphase coupling,mechanical rectification,and air breakdown.Their typical structures and working mechanisms are thoroughly discussed,and specific output performance limitations,along with corresponding optimization strategies,are identified.Furthermore,the applications of DC-TENGs in various scenarios are summarized.Finally,the challenges faced by DC-TENGs and potential solutions are analyzed to guide further advancements in this technology.

关键词： TENG direct current working mechanisms output performance limitations optimization strategies

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Molecular Chaperone-Dependent Polymer Translocation through Nanopores: The Effects of Chaperone Concentration and Chaperone-Polymer Interaction

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Chinese Journal of Polymer Science 2024年第1期42卷 125-132,I0011页

作者： Chang-Sheng Zuo Kang Wang Li-Zhen Sun Ting-Ting Sun Department of physics Zhejiang University of Science and TechnologyHangzhou 310023China Department of applied physics Zhejiang University of TechnologyHangzhou 310014China

The polymer translocation through a nanopore from a donor space(or named cis side) to a receiver space(trans side) in the chaperone-induced crowded environment has attracted increasing attention in recent years due to its significance in biological systems and technological applications. In this work, we mainly focus on the effects of chaperone concentration and chaperone-polymer interaction on the polymer translocation. By assuming the polymer translocation to be a quasi-equilibrium process, the free energy F of the polymer can be estimated by Rosenbluth-Rosenbluth method and then the translocation time τ can be calculated by Fokker-Plank equation based on the obtained free energy landscape. Our calculation results show that the translocation time can be controlled by independently tuning the chaperone concentration and chaperone-polymer interaction at the cis side or the trans side. There exists a critical chaperone-polymer attraction ε~*=-0.2 at which the volume exclusion and interaction effects of the chaperone can balance each other. Additionally, we also find that at large chaperone-polymer attraction, the translocation time is mainly governed by the diffusion coefficient of the polymer.

关键词： Polymer translocation Rosenbluth-Rosenbluth method Fokker-Plank equation Free energy landscapes

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