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Transformation regulation of the paraxial finite Airy–Gaussian beam array propagating through uniaxial electro-optic crystals 通过单轴电光晶体传播的准轴向有限 Airy-Gaussian 光束阵列的变换调节
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-12 DOI: 10.3389/fphy.2024.1426495
Long Jin, Yang Xiang
The transformation regulation of the radial finite Airy–Gaussian beam array (FAiGBA) in uniaxial crystals orthogonal to the optical axis has been explored analytically and numerically under the paraxial approximation. The analytical evolution solution of this beam array in the x- and y-directions has been derived, respectively. The intensity distribution and side view of FAiGBA propagating in three types of uniaxial crystals have been demonstrated in several instances. Furthermore, particular attention has been devoted to the linear effect when this beam array transmits through the electro-optic crystal. The influence of non-paraxial longitudinal component and temperature on FAiGBA evolution characteristics has also been examined to verify the validity of the paraxial mechanism of this beam array propagating in uniaxial crystals. It is anticipated that these research findings will contribute to the advancement of FAiGBA applications in micro- and nano-control, optical fiber communication, optical trapping, and manipulation fields.
在准轴向近似条件下,对与光轴正交的单轴晶体中径向有限空气高斯光束阵列(FAiGBA)的变换规律进行了分析和数值探索。分别得出了该光束阵列在 x 和 y 方向上的分析演化解。在三种单轴晶体中传播的 FAiGBA 的强度分布和侧视图已在多个实例中得到证明。此外,还特别关注了该光束阵列通过电光晶体时的线性效应。还研究了非同轴纵向分量和温度对 FAiGBA 演变特性的影响,以验证这种光束阵列在单轴晶体中传播的同轴机制的有效性。预计这些研究成果将有助于推动 FAiGBA 在微米和纳米控制、光纤通信、光学捕获和操纵领域的应用。
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引用次数: 0
IntervoxNet: a novel dual-modal audio-text fusion network for automatic and efficient depression detection from interviews IntervoxNet:用于从访谈中自动高效检测抑郁的新型双模态音频-文本融合网络
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-12 DOI: 10.3389/fphy.2024.1430035
Huijun Ding, Zhou Du, Ziwei Wang, Junqi Xue, Zhaoguo Wei, Kongjun Yang, Shan Jin, Zhiguo Zhang, Jianhong Wang
Depression is a prevalent mental health problem across the globe, presenting significant social and economic challenges. Early detection and treatment are pivotal in reducing these impacts and improving patient outcomes. Traditional diagnostic methods largely rely on subjective assessments by psychiatrists, underscoring the importance of developing automated and objective diagnostic tools. This paper presents IntervoxNet, a novel computeraided detection system designed specifically for analyzing interview audio. IntervoxNet incorporates a dual-modal approach, utilizing both the Audio Mel-Spectrogram Transformer (AMST) for audio processing and a hybrid model combining Bidirectional Encoder Representations from Transformers with a Convolutional Neural Network (BERT-CNN) for text analysis. Evaluated on the DAIC-WOZ database, IntervoxNet demonstrates excellent performance, achieving F1 score, recall, precision, and accuracy of 0.90, 0.92, 0.88, and 0.86 respectively, thereby surpassing existing state of the art methods. These results demonstrate IntervoxNet’s potential as a highly effective and efficient tool for rapid depression screening in interview settings.
抑郁症是全球普遍存在的精神健康问题,给社会和经济带来了巨大挑战。早期发现和治疗对于减少这些影响和改善患者预后至关重要。传统的诊断方法在很大程度上依赖于精神科医生的主观评估,这凸显了开发自动化客观诊断工具的重要性。本文介绍的 IntervoxNet 是一种新型计算机辅助检测系统,专为分析访谈音频而设计。IntervoxNet 采用了双模方法,利用音频 Mel-Spectrogram 变换器 (AMST) 进行音频处理,并结合变换器的双向编码器表示与卷积神经网络 (BERT-CNN) 的混合模型进行文本分析。在 DAIC-WOZ 数据库上进行的评估显示,IntervoxNet 表现出色,F1 分数、召回率、精确率和准确率分别达到 0.90、0.92、0.88 和 0.86,从而超越了现有的先进方法。这些结果表明,IntervoxNet 有潜力成为在访谈环境中快速筛查抑郁症的高效工具。
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引用次数: 0
Modeling the impact of coincidence loss on count rate statistics and noise performance in counting detectors for imaging applications 模拟重合损失对成像应用中计数探测器计数率统计和噪声性能的影响
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-08 DOI: 10.3389/fphy.2024.1408430
P. Zambon
Coincidence loss can have detrimental effects on the image quality provided by pixelated counting detectors, especially in dose-sensitive applications like cryoEM where the information extracted from the recorded signal needs to be maximized. In this work, we investigate the impact of coincidence loss phenomena on the recorded statistics in counting detectors producing sparse binary images. First, we derive exact analytical expressions for the mean and the variance of the recorded counts as a function of the incoming event rate. Second, we address the problem of the mean and variance of the recorded events (i.e., pixel clusters identified as individual incoming events), which also acts as a function of the incoming event rate. In this frame, we review previous studies from different disciplines on approximated two-dimensional models, and we critically reinterpret them in our context and evaluate the suitability of their adoption in the present case. The knowledge of the first two momenta of the recorded statistics allows inferring about the signal-to-noise ratio (SNR) and the detective quantum efficiency at zero frequency (DQE0). Analytical results are validated through comparison with numerical data obtained with a custom-made Monte Carlo code. We chose a realistic case study for cryoEM application consisting of a 25-µm-thick MAPS detector featuring a pixel size of 10 µm and illuminated with electrons of 300 keV energy over a wide range of incoming rate.
重合损失会对像素化计数探测器提供的图像质量产生不利影响,尤其是在低温电子显微镜等对剂量敏感的应用中,因为在这些应用中需要最大限度地从记录的信号中提取信息。在这项工作中,我们研究了重合损失现象对产生稀疏二值图像的计数探测器中记录的统计数据的影响。首先,我们推导出记录计数的均值和方差的精确分析表达式,并将其作为传入事件率的函数。其次,我们要解决记录事件(即识别为单个传入事件的像素集群)的均值和方差问题,这也是传入事件率的函数。在此框架下,我们回顾了以往不同学科对近似二维模型的研究,并根据我们的情况对其进行了批判性的重新解释,同时评估了在当前情况下采用这些模型的适宜性。通过了解记录统计量的前两个矩,可以推断信噪比(SNR)和零频率时的探测量子效率(DQE0)。分析结果通过与定制蒙特卡洛代码获得的数值数据进行比较得到验证。我们为低温电子显微镜应用选择了一个实际案例研究,它由一个 25 微米厚的 MAPS 探测器组成,像素尺寸为 10 微米,在很宽的入射率范围内用 300 千伏能量的电子照射。
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引用次数: 0
Proton electromagnetic generalized polarizabilities 质子电磁广义极化率
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-05 DOI: 10.3389/fphy.2024.1426128
N. Sparveris
Electromagnetic polarizabilities are fundamental properties of the proton that characterize its response to an external electromagnetic (EM) field. The generalization of the EM polarizabilities to non-zero four-momentum transfer opens up a powerful path to study the internal structure of the proton. They map out the spatial distribution of the polarization densities in the proton, provide access to key dynamical mechanisms that contribute to the electric and magnetic polarizability effects, and allow for the determination of fundamental characteristics of the system, such as the electric and magnetic polarizability radii. This article reviews our knowledge about proton EM generalized polarizabilities (GPs). An introduction is given to the basic concepts and the theoretical framework, which is then followed by a discussion that emphasizes the recent developments and findings of the virtual Compton scattering (VCS) experiments and future perspectives on the topic.
电磁极化性是质子的基本特性,是质子对外部电磁场反应的特征。将电磁极化率推广到非零四动量传递,为研究质子的内部结构开辟了一条强大的途径。它们描绘了质子中极化密度的空间分布,提供了获取导致电极化和磁极化效应的关键动力学机制的途径,并允许确定系统的基本特征,如电极化半径和磁极化半径。本文回顾了我们对质子电磁广义极化率(GPs)的认识。文章首先介绍了基本概念和理论框架,然后讨论了虚拟康普顿散射(VCS)实验的最新进展和发现,以及对这一主题的未来展望。
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引用次数: 0
Numerical analysis and experimental verification of time-dependent heat conduction under the action of ultra-short pulse laser 超短脉冲激光作用下随时间变化的热传导的数值分析和实验验证
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-04 DOI: 10.3389/fphy.2024.1416064
Yan Wang, Jingting Liu, Chunyan Wang, Xinmin Fan, Zhaohong Liu, Xiaodong Huang, Lujun Zhang, Sensen Li, Yu Zhang
Thermal action is a crucial process in laser processing. The classical Fourier heat conduction theory, which assumes an infinite speed of heat propagation, is commonly applied to describe steady-state and mild transient thermal processes. However, under the influence of ultra-short pulse lasers, such as those with picosecond and femtosecond durations, the heat propagation speed within the material is finite and deviates from Fourier’s law. This article addresses the unique characteristics of heat conduction in materials subjected to ultra-short pulse laser exposure by integrating Fourier’s law with the Gaussian distribution of the actual pulse laser output power density and the material’s optical absorption properties. It introduces a time variable to establish a time-dependent heat conduction equation. This equation is numerically analyzed using a difference algorithm. Based on this, simulation and experimental studies on the processing of dental hard tissues with a 1064 nm ps laser were conducted. The results show that the experimental processing depths were slightly larger than the simulation results, which may be due to damage to the dental hard tissues and the thermomechanical effects during processing. The results offer a technical reference for adjusting laser parameters in the ultra-short pulse laser processing technique.
热作用是激光加工中的一个关键过程。经典的傅立叶热传导理论假定热传播速度为无限,通常用于描述稳态和轻微瞬态热过程。然而,在超短脉冲激光器(如皮秒和飞秒持续时间的激光器)的影响下,材料内部的热传播速度是有限的,偏离了傅里叶定律。本文通过将傅里叶定律与实际脉冲激光输出功率密度的高斯分布和材料的光学吸收特性相结合,探讨了材料在超短脉冲激光照射下热传导的独特特性。它引入了一个时间变量,建立了一个随时间变化的热传导方程。该方程采用差分算法进行数值分析。在此基础上,对使用 1064 nm ps 激光加工牙科硬组织进行了模拟和实验研究。结果表明,实验加工深度略大于模拟结果,这可能是由于加工过程中对牙科硬组织的损伤和热机械效应造成的。该结果为超短脉冲激光加工技术中激光参数的调整提供了技术参考。
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引用次数: 0
An efficient approximate analytical technique for the fractional model describing the solid tumor invasion 描述实体肿瘤侵袭的分数模型的高效近似分析技术
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-04 DOI: 10.3389/fphy.2024.1294506
H. B. Chethan, Rania Saadeh, D. G. Prakasha, Ahmad Qazza, Naveen S. Malagi, M. Nagaraja, Deepak Umrao Sarwe
In this manuscript, we derive and examine the analytical solution for the solid tumor invasion model of fractional order. The main aim of this work is to formulate a solid tumor invasion model using the Caputo fractional operator. Here, the model involves a system of four equations, which are solved using an approximate analytical method. We used the fixed-point theorem to describe the uniqueness and existence of the model’s system of solutions and graphs to explain the results we achieved using this approach. The technique used in this manuscript is more efficient for studying the behavior of this model, and the results are accurate and converge swiftly. The current study reveals that the investigated model is time-dependent, which can be explored using the fractional-order calculus concept.
在本手稿中,我们推导并研究了分数阶实体肿瘤入侵模型的解析解。这项工作的主要目的是利用卡普托分数算子建立实体肿瘤侵袭模型。在这里,该模型涉及一个四方程系统,我们采用近似分析方法求解。我们使用定点定理来描述模型解系统的唯一性和存在性,并使用图形来解释我们使用这种方法所取得的结果。本手稿中使用的技术对研究该模型的行为更有效,结果准确且收敛迅速。目前的研究表明,所研究的模型与时间有关,可以使用分数阶微积分概念对其进行探索。
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引用次数: 0
Cascaded multiplier-free implementation of adaptive anti-jamming filter based on GNSS receiver 基于全球导航卫星系统接收器的无级联乘法器自适应抗干扰滤波器的实现
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-03 DOI: 10.3389/fphy.2024.1404236
Jie Song, Lei Chen, Zukun Lu, Baiyu Li, Zhe Liu, Zhihao Xue, Guangfu Sun, Wenhong Liu
Evaluating the computational complexity is critical for assessing the time-domain anti-jamming performance of GNSS receivers. The multiplier is the core component that contributes to the computational complexity in time-domain anti-jamming. However, current algorithms aimed at reducing the complexity of time-domain anti-jamming typically concentrate on shortening the filter length, which fails to address the high computational complexity introduced by the use of multipliers. This paper introduces a cascaded multiplier-free approach for implementing time-domain anti-jamming in navigation receivers. We propose a numerical power decomposition technique based on optimal Canonical Signed Digit coding and coefficient decomposition. By substituting the multiplier with minimal adder and shift operations, the computational complexity of the anti-jamming filter with a high quantization bit-width can be considerably decreased. An optimization strategy is presented, and the low-complexity multiplier-free technique is applied to the time-domain anti-jamming filter. Compared to the traditional Canonical Signed Digit multiplier-free technique, our method can reduce the components required for a 12-bit quantization anti-interference filter by one adder, 20 shift operations, and five coded word lengths, while maintaining a pseudo-range measurement deviation below 0.27 ns.
评估计算复杂度对于评估全球导航卫星系统接收器的时域抗干扰性能至关重要。乘法器是造成时域抗干扰计算复杂性的核心部件。然而,目前旨在降低时域抗干扰复杂度的算法通常集中在缩短滤波器长度上,无法解决使用乘法器带来的高计算复杂度问题。本文介绍了一种在导航接收机中实现时域抗干扰的级联无乘法器方法。我们提出了一种基于最佳 Canonical Signed Digit 编码和系数分解的数值功率分解技术。通过用最小的加法器和移位操作代替乘法器,可以大大降低高量化位宽的抗干扰滤波器的计算复杂度。本文提出了一种优化策略,并将低复杂度无乘法器技术应用于时域抗干扰滤波器。与传统的 Canonical Signed Digit 免乘法器技术相比,我们的方法可以将 12 位量化抗干扰滤波器所需的元件减少一个加法器、20 次移位运算和 5 个编码字长,同时将伪量程测量偏差保持在 0.27 ns 以下。
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引用次数: 0
Frontiers | The coupled awareness-epidemic dynamics with individualized self-initiated awareness in multiplex networks 前沿 | 多路网络中个体化自发意识的耦合意识-流行动力学
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-02 DOI: 10.3389/fphy.2024.1437341
Wei Zhang, Yixuan Ye, Zongyi Li, Jiajun Xian, Teng Wang, Dandan Liu, Die Hu, Ming Liu
The outbreak of an epidemic often stimulates the generation of public awareness about epidemic prevention. This heightened awareness encourages individuals to take proactive protective measures, thereby curbing the transmission of the epidemic. Previous research commonly adopts an assumption that each individual has the same probability of awakening self-protection awareness after infection. However, in the real-world process, different individuals may generate varying awareness responses due to the differences in the amount of information received. Therefore, in this study, we first propose a coupled awareness-epidemic spreading model, where the self-initiated awareness of each individual can be influenced by the number of aware neighbors. Subsequently, we develop a Micro Markov Chain Approach to analyze the proposed model and explore the effects of different dynamic and structural parameters on the coupled dynamics. Findings indicate that individual awareness awakening can effectively promote awareness diffusion within the proposed coupled dynamics and inhibit epidemic transmission. Moreover, the influence of awareness diffusion on epidemic transmission exhibits a metacritical point, from which the epidemic threshold increases with the increase in the awareness diffusion probability. The research findings also suggest that the increase in the average degree of virtual-contact networks can reduce the value of the metacritical point, while the change in the average degree of the physical-contact networks does not affect the metacritical point. Finally, we conduct extensive experiments on four real networks and obtain results consistent with the above conclusions. The systematic research findings of this study provide new insights for exploring the interaction between individual awareness and epidemic transmission in the real world.
流行病的爆发往往会激发公众的防疫意识。这种意识的提高会鼓励个人主动采取保护措施,从而遏制疫情的传播。以往的研究通常假设每个人在感染后唤醒自我保护意识的概率相同。然而,在现实世界的过程中,不同个体由于接收信息量的差异,可能会产生不同的意识反应。因此,在本研究中,我们首先提出了一个 "意识-流行病传播 "耦合模型,在该模型中,每个人的自发意识会受到意识邻居数量的影响。随后,我们开发了一种微马尔可夫链方法来分析所提出的模型,并探讨了不同动态和结构参数对耦合动态的影响。研究结果表明,个体意识的觉醒可以有效地促进拟议耦合动力学中的意识扩散,抑制流行病的传播。此外,意识扩散对流行病传播的影响呈现出一个元临界点,从这个临界点开始,流行病阈值随着意识扩散概率的增加而增加。研究结果还表明,虚拟接触网络平均程度的增加会降低元临界点的值,而物理接触网络平均程度的变化不会影响元临界点。最后,我们在四个真实网络上进行了大量实验,得到的结果与上述结论一致。本研究的系统性研究成果为探索现实世界中个体意识与流行病传播之间的相互作用提供了新的见解。
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引用次数: 0
A review of curved crease origami: design, analysis, and applications 弧形折痕折纸综述:设计、分析和应用
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-01 DOI: 10.3389/fphy.2024.1393435
Keyao Song, Han Li, Yang Li, Jiayao Ma, Xiang Zhou
Origami structures with morphing behaviours and unique mechanical properties are useful in aerospace deployable structures, soft robots and mechanical metamaterials. Curved-crease origami, as one of the variants in the origami family, has a curve that connects two vertices as a crease compared to the straight crease counterpart. This feature couples the crease folding and facet bending during the folding process, providing versatile design space of mechanical metamaterials with tunable stiffness, multi-stability properties and morphing behaviours. However, current design techniques are mostly for simple geometries with intuitive construction, the modelling technique focuses on using the conventional finite element method, and the intrinsically complex geometries make specimens difficult to manufacture, which further hinders the development of curved-crease origami structures. Thus, it is valuable to review the state-of-the-art in curved-crease origami. This paper presents a review on the design methodology, analytical methods, and applications of curved-crease origami over the years, discusses their strengths, identifies future challenges and provides an outlook for the future development of the curved-crease origami concept.
具有变形行为和独特机械特性的折纸结构可用于航空航天可部署结构、软机器人和机械超材料。曲折折纸是折纸家族中的一个变种,与直折纸相比,曲折折纸的折痕是连接两个顶点的曲线。这一特点将折痕折叠和折叠过程中的面弯曲结合在一起,为具有可调刚度、多稳定性能和变形行为的机械超材料提供了多样化的设计空间。然而,目前的设计技术大多针对结构直观的简单几何形状,建模技术侧重于使用传统的有限元方法,而本质上复杂的几何形状使得试样难以制造,这进一步阻碍了曲面折纸结构的发展。因此,回顾曲线折纸的最新进展是非常有价值的。本文回顾了多年来曲线折纸的设计方法、分析方法和应用,讨论了它们的优势,指出了未来的挑战,并对曲线折纸概念的未来发展进行了展望。
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引用次数: 0
A survey on deep learning in medical ultrasound imaging 医学超声成像中的深度学习调查
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-01 DOI: 10.3389/fphy.2024.1398393
Ke Song, Jing Feng, Duo Chen
Ultrasound imaging has a history of several decades. With its non-invasive, low-cost advantages, this technology has been widely used in medicine and there have been many significant breakthroughs in ultrasound imaging. Even so, there are still some drawbacks. Therefore, some novel image reconstruction and image analysis algorithms have been proposed to solve these problems. Although these new solutions have some effects, many of them introduce some other side effects, such as high computational complexity in beamforming. At the same time, the usage requirements of medical ultrasound equipment are relatively high, and it is not very user-friendly for inexperienced beginners. As artificial intelligence technology advances, some researchers have initiated efforts to deploy deep learning to address challenges in ultrasound imaging, such as reducing computational complexity in adaptive beamforming and aiding novices in image acquisition. In this survey, we are about to explore the application of deep learning in medical ultrasound imaging, spanning from image reconstruction to clinical diagnosis.
超声波成像已有几十年的历史。由于具有无创、低成本的优势,这项技术已被广泛应用于医学领域,并在超声成像方面取得了许多重大突破。尽管如此,该技术仍存在一些缺陷。因此,人们提出了一些新的图像重建和图像分析算法来解决这些问题。虽然这些新的解决方案有一定的效果,但其中很多都会带来一些其他副作用,如波束成形的计算复杂度较高。同时,医用超声设备的使用要求相对较高,对于没有经验的初学者来说不是很方便。随着人工智能技术的发展,一些研究人员已经开始努力部署深度学习来应对超声成像中的挑战,例如降低自适应波束成形的计算复杂度和帮助新手获取图像。在本研究中,我们将探讨深度学习在医学超声成像中的应用,从图像重建到临床诊断。
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引用次数: 0
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