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Saturn’s rings age, I: Reconsideration of the exposure age 土星环的年龄，1：重新考虑暴露的年龄

IF 3 2区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

Icarus

Pub Date : 2026-07-01 Epub Date: 2026-03-04 DOI: 10.1016/j.icarus.2026.117029

Gregorio Ricerchi , Aurélien Crida

At the end of the Cassini mission, Saturn’s rings have been claimed to be spectacularly young compared to the age of the Solar System: their unusual ice-rich composition corresponds to initially pure ice rings polluted by interplanetary dust particles for 100 to 400 Myr. Since then, this exposure age has been commonly accepted as the real age of the rings.

In this paper, we review the processes that are involved in determining the exposure age. We aim to see how the exposure age depends on various parameters and how relevant it is to define the real rings age. First, a new expression for the gravitational focusing onto planar rings, important parameter but crudely defined in the literature, is derived. Then, an analytical formula describing how the dust fraction varies with time in static or viscously evolving rings is provided, including possible vaporisation at impact. Finally, we introduce a cleaning process from space weathering to possibly alter dust and reduce its amount to make rings look younger than they are.

We first found that the gravitational focusing is 5 times less important than previously thought, which automatically increases the exposure age from 0.5 to 2 Gyr. Moreover, depending on the impact properties (vaporisation rate, space weathering efficiency), several billion years can easily be reached. Finally, we find that the dust fraction in the rings converges towards a finite value which, in particular with an efficient space weathering mechanism, can be close to the observed one in the current rings. In this case, neither the age nor the initial composition of the rings can be derived, and the measure of the dust fraction and bombardment rate only constrains the physical parameters of the impacts and the efficiency of the space weathering. As long as the latter parameters are not known, the exposure age argument in favour of young rings is completely undercut.

在卡西尼号任务结束时，土星环被认为比太阳系的年龄要年轻得多：它们不寻常的富含冰的组成与最初纯净的冰环相对应，这些冰环被星际尘埃颗粒污染了100至400 Myr。从那时起，这个暴露年龄就被普遍认为是土星环的真实年龄。在本文中，我们回顾了在确定暴露年龄所涉及的过程。我们的目标是了解曝光年龄如何取决于各种参数，以及它与定义真实环年龄的相关性如何。首先，导出了平面环引力聚焦的新表达式，这是文献中定义粗糙的重要参数。然后，给出了一个解析公式，描述了尘埃在静态或粘性演化环中如何随时间变化，包括撞击时可能的蒸发。最后，我们介绍了一种来自太空风化的清洁过程，可能会改变灰尘并减少其数量，使环看起来比实际年轻。我们首先发现引力聚焦的重要性比之前认为的低5倍，这自动将曝光年龄从0.5增加到2 Gyr。此外，根据撞击特性（蒸发速率、空间风化效率），几十亿年的时间很容易达到。最后，我们发现环中的尘埃分数向一个有限值收敛，特别是在有效的空间风化机制下，可以接近当前环中的观测值。在这种情况下，既不能得出环的年龄，也不能得出环的初始组成，尘埃分数和轰击率的测量只限制了撞击的物理参数和空间风化的效率。只要后一个参数不为人所知，支持年轻环存在的暴露年龄论就完全被削弱了。

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引用次数: 0

Dust, gas activity and morphology of comet 12P/Pons–Brooks at heliocentric distances beyond 1.1 au 12P/ Pons-Brooks彗星在日心距离超过1.1 au处的尘埃、气体活动和形态

IF 3 2区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

Icarus

Pub Date : 2026-07-01 Epub Date: 2026-03-09 DOI: 10.1016/j.icarus.2026.117028

Marek Husárik , Gulchehra Kokhirova , Valerii Kleshchonok , K. Aravind , Firuza Rakhmatullaeva , Margarita Safonova , Oleksandra Ivanova , Olena Shubina , Arsenii Kasianchuk

Comet 12P/Pons–Brooks is a periodic comet with an orbital period of approximately 71 years. Because of the period duration, aphelion of 35.3 au, and highly inclined orbit

(74 . 2^{\circ})

, it is classified as a Halley-type comet.

In this work, we present the results of the analysis of photometric and spectral observations of comet 12P/Pons–Brooks while it was at a heliocentric distance beyond 1.1 au, before perihelion passage. Quasisynchronous observations were carried out from July 2023 to March 2024 using 0.61-m and 1.3-m telescopes at the Skalnaté Pleso Observatory, 1-m telescope Zeiss-1000 Sanglokh International Astronomical Observatory, and 0.7-m telescope AZT8 at the observation station of Taras Shevchenko National University of Kyiv. Photometric observations were conducted using B, V, and R filters of the Johnson–Cousins and Bessel photometric systems. We completed our data collection with broadband photometric and spectral observations on the 2-m HCT telescope at the Indian Astronomical Observatory.

During this period, the dust coma morphology and photometric data measured in the R filter, such as the apparent, absolute magnitudes and dust activity level, indicate several repeated outbursts in brightness and dust activity occurred around July 22, September 25, October 17–23, and a significant outburst was recorded on November 1–7. We detected strong gas emission features in the cometary spectrum belonging to CN, C₂, and C₃ molecules. Furthermore, gas production rates of these molecules were estimated using Haser’s model. A comparison of dust activity level and CN gas production rate shows that dust activity increased significantly as the comet approached the Sun, while gas activity exhibited more moderate changes.

12P/庞斯-布鲁克斯彗星是一颗周期彗星，其轨道周期约为71年。由于它的周期、远日点35.3天文单位和高度倾斜的轨道（74.2°），它被归类为哈雷彗星。在这项工作中，我们介绍了12P/ Pons-Brooks彗星在近日点通过之前的日心距离超过1.1 au时的光度和光谱观测分析结果。2023年7月至2024年3月，在基辅塔拉斯舍甫琴科国立大学观测站，利用skalnat Pleso天文台的0.61 m和1.3 m望远镜、蔡司-1000 Sanglokh国际天文台的1 m望远镜和0.7 m望远镜AZT8进行准同步观测。光度观测使用约翰逊-考辛斯和贝塞尔光度系统的B、V和R滤光片进行。我们在印度天文台的2米HCT望远镜上通过宽带光度和光谱观测完成了数据收集。在此期间，R滤光器测量的尘埃彗发形态和光度数据，如视星等、绝对星等和尘埃活动水平，表明在7月22日、9月25日、10月17-23日前后发生了多次亮度和尘埃活动的重复爆发，其中11月1-7日发生了一次显著的爆发。我们在属于CN， C2和C3分子的彗星光谱中检测到强烈的气体发射特征。此外，利用Haser模型估计了这些分子的产气速率。尘埃活动水平和CN气体产生率的比较表明，随着彗星接近太阳，尘埃活动显著增加，而气体活动则表现出较为温和的变化。

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引用次数: 0

A physics-informed eigenfilter for artifact removal in ultrasonic scanning videos for structural inspection 用于结构检测的超声扫描视频中伪影去除的物理信息特征滤波器

IF 4.1 2区物理与天体物理 Q1 ACOUSTICS

Ultrasonics

Pub Date : 2026-07-01 Epub Date: 2026-02-08 DOI: 10.1016/j.ultras.2026.107992

Chengyang Huang, Francesco Lanza di Scalea

Artifact suppression in industrial ultrasound videos is critical for enhancing the visibility of weak structural features such as flaws. Traditional approaches such as frequency-based filtering and baseline subtraction are often limited by assumptions of perfectly separated signal components or fixed spatiotemporal alignment, which rarely hold in practice. More recent studies for artifact removal in medical ultrasound have considered eigenspace filtering that relies on the different spatiotemporal coherence between the consistent artifacts (clutter in medical imaging) and the transient signals of interest. This paper adapts the eigenfiltering approach to industrial wheel inspection system implementing a Synthetic Aperture Focus Technique (SAFT) applied to flaw imaging in railroad rails using a Rolling Search Unit (RSU). The paper clarifies key aspects of eigenfiltering applied to industrial ultrasound videos. First, it is shown that the eigenfilter effectiveness primarily stems from the large spatiotemporal autocorrelation (rather than cross-correlation) of the pseudo-stationary artifact reflections compared to the small autocorrelation of the transient flaw reflections. In addition, to address the challenges of shifting artifact positions during a scan (a very common occurrence in practical tests), the paper proposes a novel recursive eigenfilter with rectification that is different from traditional eigenfiltering. This recursive algorithm leverages a nonnegativity constraint consistent with the physics of ultrasound imaging, which iteratively reshapes the eigenspace to optimally suppress the spatiotemporally correlated artifact reflections while highlighting the uncorrelated flaw reflections. The algorithm offers excellent convergence. Experimental results obtained from RSU scanning of both artificial and natural rail flaws demonstrate outstanding filtering performance in the presence of strong artifacts. This filtering approach is widely applicable to many imaging applications involving a scanning setup.

工业超声视频中的伪影抑制对于增强弱结构特征（如缺陷）的可见性至关重要。基于频率的滤波和基线减法等传统方法往往受到完全分离信号成分或固定时空对准假设的限制，在实践中很少成立。最近的医学超声伪影去除研究考虑了特征空间滤波，该滤波依赖于一致伪影（医学成像中的杂波）和感兴趣的瞬态信号之间的不同时空相干性。本文将特征滤波方法应用于工业车轮检测系统，利用滚动搜索单元（RSU）将合成孔径聚焦技术（SAFT）应用于轨道缺陷成像。本文阐述了特征滤波在工业超声视频中的应用。首先，与瞬态缺陷反射的小自相关相比，特征滤波器的有效性主要源于伪平稳伪反射的大时空自相关（而不是互相关）。此外，为了解决扫描过程中伪影位置移位的问题（在实际测试中很常见），本文提出了一种与传统特征滤波不同的带整流的递归特征滤波器。该递归算法利用与超声成像物理特性一致的非负性约束，迭代地重塑特征空间，以最佳地抑制时空相关的伪影反射，同时突出不相关的缺陷反射。该算法具有良好的收敛性。对人造和自然轨道缺陷进行RSU扫描的实验结果表明，在存在强伪影的情况下，RSU扫描具有出色的滤波性能。这种滤波方法广泛适用于涉及扫描设置的许多成像应用。

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引用次数: 0

Study on frequency tunable resonators via variable mass 变质量调频谐振器的研究。

IF 4.1 2区物理与天体物理 Q1 ACOUSTICS

Ultrasonics

Pub Date : 2026-07-01 Epub Date: 2026-02-07 DOI: 10.1016/j.ultras.2026.107997

Zitong Mai, Xiping He, Maiwei Liao, Zhibo Li

This study proposes a frequency tunable ultrasonic resonator based on a variable mass method, in which a metal ring, i.e., a tuning frequency ring (TFR) is mounted on the resonator. The resonant frequency of the resonator is adjusted by altering the position of the TFR, which introduces changes in both inertia and stiffness. LTspice were conducted to investigate the effects of the TFR’s size, material, and position on the resonant frequency, with experimental measurements further validating the results. Contrary to the conventional belief that adding mass lowers the frequency, the study reveals that placing the TFR near the displacement node can increase the resonant frequency. The results also demonstrate that the tuning range of the system can be controlled by modifying the TFR’s geometry and material properties. For a resonator with a resonant frequency of 28 kHz, when the mass of the TFR is about 36 g, studies show that the maximum tunable frequency range is 9 kHz. Based on the energy method, the equivalent mass and stiffness of the resonator were calculated using the SECM (Segmented Equivalent Circuit Model) and cubic spline interpolation, explaining the physical mechanism of frequency tuning using the variable mass method, providing a practical solution for achieving wide-range frequency tuning in ultrasonic resonators.

本研究提出了一种基于变质量法的频率可调超声谐振器，在谐振器上安装一个金属环，即调谐频率环（TFR）。通过改变TFR的位置来调整谐振器的谐振频率，从而引入惯性和刚度的变化。LTspice研究了TFR的尺寸、材料和位置对谐振频率的影响，并通过实验测量进一步验证了结果。与增加质量降低频率的传统观点相反，研究表明，将TFR放置在位移节点附近可以提高谐振频率。结果还表明，可以通过改变TFR的几何形状和材料特性来控制系统的调谐范围。对于谐振频率为28 kHz的谐振器，当TFR质量约为36 g时，研究表明其最大可调谐频率范围为9 kHz。基于能量法，利用分段等效电路模型（SECM）和三次样条插值计算了谐振器的等效质量和刚度，解释了变质量法频率调谐的物理机理，为实现超声谐振器的大范围频率调谐提供了一种实用的解决方案。

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引用次数: 0

Analytical and probabilistic results arising from the dynamics of quantum κ-disentropy 量子失熵动力学的解析性和概率性结果

IF 2.6 3区物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY

Physics Letters A

Pub Date : 2026-06-15 Epub Date: 2026-03-03 DOI: 10.1016/j.physleta.2026.131538

José Leonardo Esteves Da Silva , David Carneiro De Souza

This work presents new analytical and probabilistic results arising from the dynamics of quantum κ-disentropy, a functional used to quantify entanglement and uses the Lambert-Kaniadakis W_κ(x) function in its kernel- a recent generalization of the Lambert W function based on the Kaniadakis κ-exponential function. First, we show how Rényi-based κ-disentropy (and consequently κ-disentropy) can be used to indicate the purity of a qubit state in the Bloch sphere. Second, we apply κ-disentropy to measure the disentanglement of two-qubit random quantum states in quantum networks, demonstrating that this functional exhibits behavior dual to the Wooters entanglement entropy formula (Wootters, W. K. Phys. Rev. Lett. 1998). Finally, we described how the quasi-probability of Fock states can be computed using the Lambert-Kaniadakis function and how the quantum relative Rényi-based κ-disentropy measures the distance between Wigner functions in phase space.

这项工作提出了由量子κ-非熵动力学产生的新的分析和概率结果，量子κ-非熵是一种用于量化纠缠的函数，并在其核中使用Lambert-Kaniadakis Wκ(x)函数-基于Kaniadakis κ-指数函数的Lambert W函数的最新推广。首先，我们展示了如何使用基于r -disentropy（以及随后的κ-disentropy）来表示布洛赫球中量子比特状态的纯度。其次，我们应用κ-disentropy来测量量子网络中两个量子位随机量子态的解纠缠，证明该函数表现出与Wooters纠缠熵公式对偶的行为（Wooters， W. K. Phys）。Rev. Lett. 1998)。最后，我们描述了如何使用Lambert-Kaniadakis函数计算Fock态的准概率，以及如何使用基于r的量子相对熵来测量相空间中Wigner函数之间的距离。

引用次数: 0

Solving the exactly explicit solutions of the conformable space-time fractional Phi-4 equation via neural networks method 利用神经网络方法求解符合时空分数阶pi -4方程的精确显式解

IF 2.6 3区物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY

Physics Letters A

Pub Date : 2026-06-15 Epub Date: 2026-02-27 DOI: 10.1016/j.physleta.2026.131535

Zhao Li

The challenge of obtaining accurate analytical solutions for fractional partial differential equation is addressed in this study, a problem deemed important due to the critical role of fractional partial differential equation in modeling complex phenomena with memory and non-local effects. This article aims to study a solver based on artificial neural networks for obtaining accurate analytical solutions of fractional partial differential equation. A general analytical solution method for fractional partial differential equations is proposed by utilizing the powerful function approximation ability of neural networks and combining it with the trial function method. The method is applied to the fractional Phi-4 equation and a series of exact analytical solutions are obtained. In addition, with the help of Matlab mathematical software, three-dimensional graphics, two-dimensional curves, and contour maps of partial solutions are drawn to visually display the morphological characteristics of the understanding, verifying the effectiveness and practicality of the proposed method.

由于分数阶偏微分方程在模拟具有记忆和非局部效应的复杂现象中起着至关重要的作用，本研究解决了分数阶偏微分方程精确解析解的难题。本文旨在研究一种基于人工神经网络的分数阶偏微分方程精确解析解求解器。利用神经网络强大的函数逼近能力，将其与试函数法相结合，提出了分数阶偏微分方程的一般解析解方法。将该方法应用于分数阶Phi-4方程，得到了一系列精确解析解。此外，借助Matlab数学软件绘制了部分解的三维图形、二维曲线和等高线图，直观地展示了所理解的形态特征，验证了所提方法的有效性和实用性。

引用次数: 0

An extensional study of charge resonance enhanced ionization of polyatomic molecule in strong laser fields: CH3Cl 强激光场中多原子分子电荷共振增强电离的扩展研究：CH3Cl

IF 2.6 3区物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY

Physics Letters A

Pub Date : 2026-06-15 Epub Date: 2026-03-05 DOI: 10.1016/j.physleta.2026.131469

Yingbo Shi, Guoqiang Shi, Siyuan Dong, Jia Yi, Peng Yuan, Wenxuan Yao, Shaohua Sun, Bitao Hu, Zuoye Liu

We have experimentally and theoretically investigated the charge resonance enhanced ionization (CREI) dominated dissociation dynamics of the polyatomic molecule CH₃Cl. This study have demonstrated that the CREI model previously established for generalized homonuclear diatomic molecules retains its validity even for generalized heteronuclear diatomic molecules CH₃Cl. CREI is a process that is highly sensitive to the internuclear distance between C and Cl prior to the Coulomb explosion (CE) of CH₃Cl

^{2 +}

, i.e., the pump-probe delay. The low energy CE channel of CH₃Cl

^{2 +}

is attributed to the CREI mechanism, as evidenced by the delay-dependent changes in its total kinetic energy release (KER) and enhancement. Additionally, the classical and AIMD methods indicate that 59 and 108 fs are required for the CH₃Cl

^{+}

to reach the critical internuclear distance, respectively.

从实验和理论上研究了电荷共振增强电离（CREI）主导的多原子分子CH3Cl的离解动力学。本研究表明，以前建立的广义同核双原子分子的CREI模型即使对广义异核双原子分子CH3Cl也保持其有效性。CREI是一个对CH3Cl2+库仑爆炸（CE）前C和Cl的核间距离，即泵浦-探针延迟高度敏感的过程。CH3Cl2+的低能CE通道归因于CREI机制，其总动能释放（KER）和增强的延迟依赖性变化证明了这一点。此外，经典方法和AIMD方法表明，CH3Cl+分别需要59和108 fs才能达到临界核间距离。

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引用次数: 0

Ballistic gradiometer based on microsphere dynamics in a Gaussian laser beam 基于高斯激光束微球动力学的弹道梯度仪

IF 2.6 3区物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY

Physics Letters A

Pub Date : 2026-06-15 Epub Date: 2026-03-01 DOI: 10.1016/j.physleta.2026.131541

Aleksei S. Leshchev, Yuri V. Rozhdesvenskii

In this article, we present a gradiometer based on the dynamics of a dielectric microparticle in an optical radiation field with a Gaussian beam profile. The particle oscillates in a gravitational field and an optical field, creating an optical pendulum without any mechanical parts. The dynamics of the particle depend on gravitational field which enables precise measurement of the gravity acceleration. We present a conceptual design of the gradiometer and estimate the impact of various noise sources. This method offers an estimated accuracy of

0.05 E

for

11000 s

, which is higher than accuracy of quantum gradiometers.

在本文中，我们提出了一个基于电介质微粒在高斯光束分布的光辐射场中的动力学的梯度计。粒子在引力场和光场中振荡，形成一个没有任何机械部件的光学摆。粒子的动力学依赖于引力场，从而可以精确地测量重力加速度。我们提出了梯度计的概念设计，并估计了各种噪声源的影响。该方法的估计精度为0.05E / 11000s，高于量子梯度仪的精度。

引用次数: 0

Assessing the influence of orientation and surrounding texture on plastic response of porous crystals through a crystal plasticity and data driven modeling approach 通过晶体塑性和数据驱动建模方法评估取向和周围织构对多孔晶体塑性响应的影响

IF 2.6 3区物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY

Physics Letters A

Pub Date : 2026-06-15 Epub Date: 2026-02-23 DOI: 10.1016/j.physleta.2026.131522

Sagar Chandra , Harsh Hemani , Vivek M. Chavan

This paper presents a data-driven surrogate modeling framework for crystal plasticity analysis of orientation dependent porosity evolution in isolated single crystals as well as in cases where the porous crystal is embedded as a central grain in various polycrystalline textures. An ensemble learning approach is implemented via various machine learning methods to learn the intrinsic data representations and predict the yield strength, coalescence strain and void growth rate in porous ductile crystals. The learning frameworks are also assessed by predicting these output variables for a new set of orientations in isolated single crystals and in cases where the porous crystal is embedded in polycrystalline environment with different textures. Corresponding crystal plasticity simulations are also performed to authenticate these predictions of machine learning. The likes of the present work are expected to fundamentally transform the analysis of void mediated plasticity and damage behavior in anisotropic ductile solids.

本文提出了一个数据驱动的替代建模框架，用于在孤立的单晶中以及在多孔晶体作为中心晶粒嵌入各种多晶结构的情况下，对取向相关孔隙度演化的晶体塑性分析。通过多种机器学习方法实现集成学习方法，学习多孔延性晶体的内在数据表示，并预测其屈服强度、聚结应变和空洞生长速率。通过预测在孤立的单晶和多孔晶体嵌入具有不同纹理的多晶环境中的一组新取向的输出变量，还可以评估学习框架。还进行了相应的晶体塑性模拟来验证机器学习的这些预测。类似的工作有望从根本上改变各向异性韧性固体中空洞介导的塑性和损伤行为的分析。

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引用次数: 0

Dynamics of entanglement and nonclassicality in a time-dependent Dirac oscillator 时变狄拉克振荡器中的纠缠动力学和非经典性

IF 2.6 3区物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY

Physics Letters A

Pub Date : 2026-06-15 Epub Date: 2026-03-03 DOI: 10.1016/j.physleta.2026.131544

Yassine Chargui , Abdelmalek Boumali

This paper has a twofold objective: First, we present the exact treatment of a

(1 + 1)

-dimensional Dirac oscillator where the mass and the frequency vary in time as:

m = m_{0} e^{γ t}

and

ω = ω_{0} e^{- γ t}

. This choice allows separable solutions in time and space, obtained via a direct method. Second, motivated by the model’s equivalence to the Anti-Jaynes-Cummings interaction between a two-level atom and a single-mode quantized field, we investigate the dynamics of quantum entanglement between the chirality (atom) and position (field) degrees of freedom, along with the individual nonclassicalities of each subsystem, assuming the field starts in a number state. Entanglement is quantified by negativity and Von Neumann entropy, while nonclassicality is assessed via entanglement potential, Wigner function negativity, and a skew information-based measure. The analysis reveals that both the entanglement and individual nonclassicalities dynamically stabilize at nonzero values, in contrast to the time-independent case, where these quantities undergo persistent oscillations.

本文有两个目的：首先，我们给出了质量和频率随时间变化为m=m0e - γt和ω=ω0e - γt的（1+1）维狄拉克振荡器的精确处理。这种选择允许在时间和空间上可分离的解，通过直接方法获得。其次，由于该模型等效于两能级原子和单模量子化场之间的Anti-Jaynes-Cummings相互作用，我们研究了手性（原子）和位置（场）自由度之间的量子纠缠动力学，以及每个子系统的个体非经典性，假设场从数字状态开始。纠缠通过负性和冯·诺依曼熵来量化，而非经典性通过纠缠势、维格纳函数负性和基于偏态信息的度量来评估。分析表明，与时间无关的情况相反，纠缠和个体非经典性都动态稳定在非零值，其中这些量经历持续振荡。

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引用次数: 0

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