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超表面:塑造光子学的未来

Science Bulletin 2024年第11期69卷 1607-1611页

作者： Nikolay l.Kazanskiy Svetlana N.Khonina Muhammad A.Butt Samara National Research University Samara 443086Russia

A metasurface, often abbreviated as MS, represents a thin, artificially crafted surface consisting of an assembly of subwavelength structures that interact with light in distinct manners. Typically,smaller than the wavelength of the light they engage with, these structures empower precise management of light properties such as polarization, phase, and amplitude.

关键词： precise abbreviated 光子学

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基于VMD的MAG焊输入端电信号频域分析

天津大学学报（自然科学与工程技术版） 2024年第4期57卷 394-402页

作者：吕小青苏浩洋天津大学材料科学与工程学院天津300350 天津市先进连接技术重点实验室天津300350

通过电信号采集平台,对焊机输入输出端电信号进行同步采集.分析弧焊电源整流电路,对输入电信号进行整流处理得到输入电压与电流,最终计算得到弧焊电源的输入功率.经过对比发现输出电流与瞬时输入功率峰值变化趋势基本一致.论述了变分模... 详细信息

通过电信号采集平台,对焊机输入输出端电信号进行同步采集.分析弧焊电源整流电路,对输入电信号进行整流处理得到输入电压与电流,最终计算得到弧焊电源的输入功率.经过对比发现输出电流与瞬时输入功率峰值变化趋势基本一致.论述了变分模态分解(VMD)原理及方法,并对瞬时输入功率进行分解,得到一系列特征BlIMFs信号.通过对不同过渡模式(大滴过渡、短路过渡和混合过渡)下瞬时输入功率信号、特征IMF信号和焊接输出电流信号在频域上的对比分析,发现VMD能够有效得到低频(IMF1)、中频(IMF2)和高频信号(IMF3),且中频和高频信号表现出了焊机不控整流的脉动信息(300 hz)以及电网的干扰.而低频IMF1信号与焊接输出电流信号频域一致性良好,并在时域上也有良好的一致性.结果表明了通过对输入瞬时功率的VMD,其低频分量能够有效表征焊接过程,从而为从输入端评定过渡过程稳定性提供了一种新思路.

关键词： MAG焊瞬时输入功率变分模态分解频谱分析

On an isotropic porous solid cylinder:the analytical solution and sensitivity analysis of the pressure

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1499-1522页

作者： h.ASGhARI l.MIllER R.PENTA J.MERODIO Departamento de Matemática Aplicada a las TIC ETS de Ingeniería de Sistemas Informáticos Universidad Politecnica de Madrid School of Mathematics and Statistics University of Glasgow

Within this work, we perform a sensitivity analysis to determine the influence of the material input parameters on the pressure in an isotropic porous solid *** provide a step-by-step guide to obtain the analytical solution for a porous isotropic elastic cylinder in terms of the pressure, stresses, and elastic displacement. We obtain the solution by performing a laplace transform on the governing equations, which are those of Biot's poroelasticity in cylindrical polar coordinates. We enforce radial boundary conditions and obtain the solution in the laplace transformed domain before reverting back to the time domain. The sensitivity analysis is then carried out, considering only the derived pressure solution. This analysis finds that the time t, Biot's modulus M, and Poisson's ratio ν have the highest influence on the pressure whereas the initial value of pressure P0plays a very little role.

关键词：

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特提斯地球动力系统研究新进展

中国科学：地球科学 2024年第3期54卷 892-896页

作者：丁林中国科学院青藏高原研究所青藏高原地球系统与资源环境全国重点实验室北京100101

特提斯洋(Tethyan Ocean)最早由奥地利地质学家Eduard Suess在1893年提出.欧洲地质学家通过对它的研究发展了现代地质学,但并未对板块构造理论的诞生提供核心科学支撑(Trümpy, 2001).随着研究的不断深入,特提斯的概念从一个中生代的大... 详细信息

特提斯洋(Tethyan Ocean)最早由奥地利地质学家Eduard Suess在1893年提出.欧洲地质学家通过对它的研究发展了现代地质学,但并未对板块构造理论的诞生提供核心科学支撑(Trümpy, 2001).随着研究的不断深入,特提斯的概念从一个中生代的大洋演变成涵盖整个显生宙的原特提斯、古特提斯和新特提斯三个长期演化的大洋(图1;吴福元等, 2020)。

关键词：板块构造理论地球动力系统特提斯吴福元地质学家显生宙

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论地方性知识、群体性知识和原地方性知识

东南大学学报（哲学社会科学版） 2024年第2期26卷 35-42,F0002,146页

作者：吕乃基东南大学人文学院江苏南京210096

知识在内容上涉及人与自然、人际和人己三大关系,大致相应于普适性、地方性和个人知识,三种知识相互渗透。地方性知识实为群体性知识。知识因认识过程而异。原地方性知识是一种特殊的知识,不是本体论和认识论意义上的知识。原地方性知... 详细信息

知识在内容上涉及人与自然、人际和人己三大关系,大致相应于普适性、地方性和个人知识,三种知识相互渗透。地方性知识实为群体性知识。知识因认识过程而异。原地方性知识是一种特殊的知识,不是本体论和认识论意义上的知识。原地方性知识因其边界条件和初始条件而具有特定的时空观:在空间上规训个人知识和群体性知识,大多数情况下难以接受普适性知识;在时间上,原地方性知识因其“原”的属性而难以改变,延续动物世界的弱肉强食以及伴随人作为“类”的终生。这是事实判断,而非价值判断或逻辑判断。由知识论探讨原地方性知识,既丰富知识论的研究领域,也为研究“地方(群体)”的分殊提供新的视角。

关键词：地方性知识群体性知识原地方性知识传统文化

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Bi_(2)O_(2)Se纳米线的生长及其超导量子干涉器件

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物理学报 2024年第4期73卷 285-290页

作者：刘怀远肖建飞吕昭征吕力屈凡明中国科学院物理研究所北京凝聚态物理国家研究中心北京100190 中国科学院大学物理科学学院北京100049 合肥国家实验室合肥230088

Bi_(2)O_(2)Se是一种新型半导体材料,具有载流子迁移率高、空气中稳定和自旋轨道耦合强等优点,并且其合成方法多种多样,应用范围十分广泛.但已有研究大多集中在其二维薄膜,本文介绍一种使用三温区管式炉通过化学气相沉积生长Bi_(2)O_(2... 详细信息

Bi_(2)O_(2)Se是一种新型半导体材料,具有载流子迁移率高、空气中稳定和自旋轨道耦合强等优点,并且其合成方法多种多样,应用范围十分广泛.但已有研究大多集中在其二维薄膜,本文介绍一种使用三温区管式炉通过化学气相沉积生长Bi_(2)O_(2)Se一维纳米线的方法,研究了云母衬底处于水平方向不同位置以及竖直方向不同高度对Bi_(2)O_(2)Se纳米线生长的影响,并归纳出适于其生长的优化条件.之后,基于生长的Bi_(2)O_(2)Se纳米线构建了超导量子干涉器件,并观测到随磁场的超导量子干涉,为拓宽Bi_(2)O_(2)Se纳米线的应用提供了思路.

关键词： Bi_(2)O_(2)Se纳米线化学气相沉积超导量子干涉器

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 ll Pauli forbidden, it is safe to discard them. 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