Accepted
, , Received Date: 2025-03-18
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, , Received Date: 2024-08-28
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Arthropods, including spiders and mantises, can maintain their body stability on shaking surfaces, such as spiderwebs or leaves. This impressive stability can be attributed to the specific geometric shape of their limbs, which exhibit an M-shaped structure. Inspired by this geometry, this work proposes an arthropod-limb-inspired M-shaped structure for low-frequency vibration isolation. First, the design method of the M-shaped quasi-zero-stiffness (QZS) structure is presented. A static analysis of potential energy, restoring force, and equivalent stiffness is conducted, showing that the M-shaped structure enables a horizontal linear spring to generate nonlinear stiffness in the vertical direction. More importantly, this nonlinear stiffness effectively compensates for the negative stiffness in large-displacement responses, thereby achieving a wider quasi-zero-stiffness region than the conventional three-spring-based QZS structure. Subsequently, the harmonic balance method is employed to derive approximate analytical solutions for the M-shaped QZS structure, which are well validated through numerical simulation. A comparison between the proposed M-shaped QZS structure and the conventional three-spring-based QZS structure is performed. Results show that the M-shaped QZS structure is advantageous for reducing both the cut-in isolation frequency and the resonance frequency. In particular, under large excitation or small damping conditions, the performance improvement of the M-shaped QZS structure in terms of reducing the resonance frequency and maximum response becomes more pronounced. The underlying mechanism behind this feature is primarily attributed to the expanded QZS region induced by the M-shaped structure. Finally, since the M-shaped structures vary among different arthropods, the effect of the geometry of M-shaped structures on low-frequency vibration performance is investigated. Interestingly, a trade-off between vibration isolation performance and loading mass is observed. As the M-shaped structure becomes flatter and the QZS region expands, the cut-in isolation frequency, resonance frequency/peak, and loading mass all decrease. This occurs because a flatter M-shaped structure leads to a reduction in the equivalent stiffness generated by the horizontal stiffness. Therefore, as the loading mass capacity decreases, the low-frequency vibration isolation performance is enhanced. This novel finding provides a reasonable explanation for why most arthropods possess many pairs of limbs, allowing the loading mass to be distributed while achieving excellent low-frequency vibration isolation.
, , Received Date: 2025-04-07
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Circular cross-section plasma is the most basic form of tokamak plasma and the fundamental configuration for magnetic confinement fusion experiments. Based on the HL-2A limiter discharge experiments, the magnetohydrodynamic (MHD) equilibrium and MHD instability of circular cross-section tokamak plasmas are investigated in this work. The results show that when $ {q}_{0}=0.95 $, the internal kink mode of $ m/n=1/1 $ is always unstable. The increase in plasma $ \beta $ (the ratio of thermal pressure to magnetic pressure) can lead to the appearance of external kink modes. The combination of axial safety factor $ {q}_{0} $ and edge safety factor $ {q}_{{\mathrm{a}}} $ determines the equilibrium configuration of the plasma and also affects the MHD stability of the equilibrium, but its growth rate is also related to the size of $ \beta $. Under the condition of $ {q}_{{\mathrm{a}}} > 2 $ and $ {q}_{0} $ slightly greater than $ 1 $, the internal kink mode and surface kink mode can be easily stabilized. However the plasma becomes unstable again and the instability intensity increases as $ {q}_{0} $ continues to increase when $ {q}_{0} $ exceeds $ 1 $. As the poloidal specific pressure ($ {\beta }_{{\mathrm{p}}} $) increases, the MHD instability develops, the equilibrium configuration of MHD elongates laterally, and the Shafranov displacement increases, which in turn has the effect on suppressing instability. Calculations have shown that the maximum $ \beta $ value imposed by the ideal MHD mode in a plasma with free boundary in tokamak experiments is proportional to the normalized current $ {I}_{{\mathrm{N}}} $ ($ {I}_{{\mathrm{N}}}={I}_{{\mathrm{p}}}\left({\mathrm{M}}{\mathrm{A}}\right)/a\left({\mathrm{m}}\right){B}_{0}\left({\mathrm{T}}\right) $), and the maximum specific pressure $ \beta \left({\mathrm{m}}{\mathrm{a}}{\mathrm{x}}\right) $ is calibrated to be $ ~2.01{I}_{{\mathrm{N}}},{\mathrm{ }}{\mathrm{i}}. {\mathrm{e}}. $ $ \beta \left({\mathrm{m}}{\mathrm{a}}{\mathrm{x}}\right)~2.01{I}_{{\mathrm{N}}} $. The operational $ \beta $ limit of HL-2A circular cross-section plasma is approximately $ {\beta }_{{\mathrm{N}}}^{{\mathrm{c}}}\approx 2.0 $. Too high a value of $ {q}_{0} $ is not conducive to MHD stability and leads the $ \beta $ limit value to decrease. When $ {q}_{0}=1.3 $, we obtain a maximum value of $ {\beta }_{{\mathrm{N}}} $ of approximately $ 1.8 $. Finally, based on the existing circular cross-section plasma, some key factors affecting the operational $ \beta $ and the relationship between the achievable high $ \beta $ limit and the calculated ideal $ \beta $ limit are discussed.
,
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Neutral atom arrays have emerged as one of the most promising physical platforms for quantum computing and quantum information processing due to their precise single-atom control and tunable strong interactions. The acousto-optic deflector (AOD) is a key device for constructing and manipulating neutral atom arrays, enabling rapid and high-precision atom trapping and arrangement. However, TeO2-based anomalous Bragg AODs still face challenges in practical applications, such as unclear broadband diffraction conditions, polarization sensitivity, and low efficiency, which limit their performance in multi-degree-of-freedom control.
This study investigates the acousto-optic effects in AOD and acousto-optic modulator (AOM), revealing their differences in diffraction efficiency, polarization characteristics, and applications. By adjusting the azimuthal angle of the AOD, we measured the efficiency and RF bandwidth of the ±1st-order diffracted beams under horizontal and vertical polarization incident light, proposed an experimental method to determine the broadband diffraction center frequency and diffraction order. Additionally, we systematically characterized the operational parameters of AOM, clarifying their performance mechanisms and application-specific differences compared to AOD. The main conclusions are as follows:
(I) The beam deflection performance of an AOD is closely related to the ultrasonic mode or acoustic velocity: a lower sound velocity results in a larger deflection angles. For TeO2 crystals, when a shear wave propagates along the [110] axis (sound velocity: 0.617 km/s), the diffraction angle reaches 0.842 mrad/MHz (laser wavelength: 532 nm). In contrast, when TeO2 is used in AOM with a longitudinal wave along the [001] axis (sound velocity: 4.26 km/s), the diffraction angle decreases to 0.133 mrad/MHz under the same wavelength.
(II) To achieve high diffraction efficiency and a broad operational frequency range, the AOD must satisfy the phase-matching condition for anomalous Bragg diffraction. Taking the AOD (model: AA DTSX-250) as an example, it operates in a unidirectional incident mode: when horizontally polarized light (extro-ordinary light) is incident, only the -1st-order diffracted beam satisfies the anomalous Bragg condition. The beam undergoes polarization conversion to vertically polarized light (ordinary light), enabling high-efficiency broadband deflection (center frequency: 82 MHz, bandwidth: 45 MHz). To support future twodimensional deflection implementations, the input and output surfaces of the TeO2 crystal are fabricated with slight bevel angles, ensuring collinearity between the -1st-order diffracted beam and the incident beam at the center frequency. In other cases — (i) +1st-order diffraction of horizontally polarized light and (ii) ±1st-order diffraction of vertically polarized light — the anomalous Bragg condition is not met. These beams retain their original polarization and allow only narrowband deflection.
These results demonstrate that AODs, leveraging anomalous acoustooptic effects, can achieve high diffraction efficiency, wide frequency tuning ranges, and large deflection angles, making them suitable for high-speed, high-precision beam steering applications. In contrast, AOMs utilize normal acousto-optic effects to perform rapid modulation of beam intensity, frequency, and phase, and are widely used in laser communication and optical fiber transmission. This study provides a detailed technical reference for understanding the operational principles of AODs and their applications in programmable neutral atom arrays.
This study investigates the acousto-optic effects in AOD and acousto-optic modulator (AOM), revealing their differences in diffraction efficiency, polarization characteristics, and applications. By adjusting the azimuthal angle of the AOD, we measured the efficiency and RF bandwidth of the ±1st-order diffracted beams under horizontal and vertical polarization incident light, proposed an experimental method to determine the broadband diffraction center frequency and diffraction order. Additionally, we systematically characterized the operational parameters of AOM, clarifying their performance mechanisms and application-specific differences compared to AOD. The main conclusions are as follows:
(I) The beam deflection performance of an AOD is closely related to the ultrasonic mode or acoustic velocity: a lower sound velocity results in a larger deflection angles. For TeO2 crystals, when a shear wave propagates along the [110] axis (sound velocity: 0.617 km/s), the diffraction angle reaches 0.842 mrad/MHz (laser wavelength: 532 nm). In contrast, when TeO2 is used in AOM with a longitudinal wave along the [001] axis (sound velocity: 4.26 km/s), the diffraction angle decreases to 0.133 mrad/MHz under the same wavelength.
(II) To achieve high diffraction efficiency and a broad operational frequency range, the AOD must satisfy the phase-matching condition for anomalous Bragg diffraction. Taking the AOD (model: AA DTSX-250) as an example, it operates in a unidirectional incident mode: when horizontally polarized light (extro-ordinary light) is incident, only the -1st-order diffracted beam satisfies the anomalous Bragg condition. The beam undergoes polarization conversion to vertically polarized light (ordinary light), enabling high-efficiency broadband deflection (center frequency: 82 MHz, bandwidth: 45 MHz). To support future twodimensional deflection implementations, the input and output surfaces of the TeO2 crystal are fabricated with slight bevel angles, ensuring collinearity between the -1st-order diffracted beam and the incident beam at the center frequency. In other cases — (i) +1st-order diffraction of horizontally polarized light and (ii) ±1st-order diffraction of vertically polarized light — the anomalous Bragg condition is not met. These beams retain their original polarization and allow only narrowband deflection.
These results demonstrate that AODs, leveraging anomalous acoustooptic effects, can achieve high diffraction efficiency, wide frequency tuning ranges, and large deflection angles, making them suitable for high-speed, high-precision beam steering applications. In contrast, AOMs utilize normal acousto-optic effects to perform rapid modulation of beam intensity, frequency, and phase, and are widely used in laser communication and optical fiber transmission. This study provides a detailed technical reference for understanding the operational principles of AODs and their applications in programmable neutral atom arrays.
TDOA/DOA hybrid location method of partial discharge combined with blind signal separation algorithm
, , Received Date: 2025-03-11
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To address the technical bottleneck of decoupling spatiotemporal feature, high hardware costs, and high computational complexity in ultrasonic detection of partial discharge (PD) in electrical equipment, this paper proposes a TDOA/DOA hybrid localization method based on kernel principal component analysis (KPCA) and modified noncircular FastICA (mnc-FastICA). By integrating spatiotemporal feature extraction with intelligent optimization mechanisms, this method achieves high-precision localization by using a small-scale sensor array. The key innovations are as follows. First, a KPCA-assisted pseudo-whitening preprocessing framework is constructed by using polynomial kernel mapping for nonlinear signal dimensionality reduction, which preserves the correlation between time delay (TDOA) and direction-of-arrival (DOA) features while suppressing environmental noise. Second, after the blind separation of ultrasonic signals via the mnc-FastICA algorithm, TDOA/DOA parameters are synchronously extracted through a combination of the generalized cross-correlation (GCC) method and array manifold analysis. Finally, a maximum likelihood estimation model integrating dual parameters is established, and the African vulture optimization algorithm (AVOA) is introduced to accelerate global optimal solution convergence. Experimental results demonstrate that with a compact hardware configuration of two orthogonal arrays (8 sensors in total), the proposed method achieves a TDOA estimation error of 2.34%, DOA estimation accuracy better than 2°, and localization errors as low as 1.54 cm. This approach effectively resolves the discrepancies among spatiotemporal feature coupling, hardware cost, and localization accuracy in PD detection, providing a novel solution for condition monitoring of electrical equipment.
, , Received Date: 2025-03-24
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Three-dimensional (3D) graphene materials have excellent electronic emission performance and mechanical stability, showing significant advantages in the field of high current density field emitters. In this study, copper oxide modified three-dimensional graphene composites (LIG/CuO) are prepared in situ by a femtosecond laser one-step method, which realizes the simultaneous regulation of cork carbonization and copper oxidation. Shallow copper-rich precursors are constructed by copper salt infiltration and ascorbic acid reduction. Laser irradiation is used to synchronously induce the carbonization of cellulose into few-layer graphene and the transformation of Cu into CuO, forming a three-dimensional fiber network of microcrystalline graphene coated with CuO nanoparticles (30—80 nm). The structure exhibits excellent field emission performance: the threshold field of preparing pure laser- induced graphene (LIG) is ~2.12 V/μm and the field enhancement factor is ~8223. After optimizing CuO loading, the threshold field of LIG/CuO-5 is reduced to 1.57 V/μm, the field enhancement factor rises up to ~8823, and the ultra-high current density of 22.71 mA/cm2 is achieved at 2.89 V/μm. The density functional theory (DFT) calculations show that the electrons at the heterojunction interface transfer from CuO to graphene, which reduces the work function of graphene from 4.833 eV to 4.677 eV, and the band bending of CuO surface synergistically reduces the tunneling barrier. In addition, the local electric field enhancement effect of CuO nanoparticles and the optimized distribution density synergistically increase the effective emission point density. The performance improvement is mainly attributed to three synergistic effects: (Ⅰ) the three-dimensional porous graphene network provides abundant tip emission sites; (Ⅱ) the introduction of CuO nanoparticles reduces the work function of the composite material from 4.833 eV to 4.667 eV, effectively reducing the electron escape barrier; (Ⅲ) the heterojunction interface forms a directional electron migration channel under a positive bias electric field, combined with the excellent conductivity of LIG, which significantly improves the electron tunneling efficiency.
, , Received Date: 2025-03-26
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This study aims to establish the intrinsic link between the high-temperature rheological behavior and kinetic relaxation characteristics of La-based metallic glasses. By conducting dynamic mechanical analysis and high-temperature tensile strain-rate jump experiments on three La-based metallic glasses with significant β relaxation, and combining the findings within the free volume theory framework, their high-temperature rheological properties are investigated systematically. The results show that the steady-state flow stress and activation volume evolution trend are consistent within the normalized temperature range. The average activation energy for high-temperature rheology aligns with the activation energy range of α relaxation, confirming the strong association between rheological behavior and α relaxation. The activation energy for β relaxation shows an opposite trend, indicating that it may precede α relaxation. A dynamic competition between defect annihilation and generation governs the rheological behavior, and kinetic parameters reveal the temperature and strain-rate sensitivity of metallic glasses. This study lays a theoretical foundation for optimizing the high-temperature mechanical properties of La-based metallic glasses and also provides new insights into understanding the coupling relationship between multi-scale relaxation behavior and rheological mechanisms in metallic glasses.
,
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The emergence of large language models has significantly advanced scientific research. Representative models such as ChatGPT and DeepSeek R1 have brought notable transformations to the paradigm of scientific research. While these models are general-purpose, they have demonstrated strong generalization capabilities in the field of batteries, particularly in solid-state battery research. In this study, we systematically screened 5,309,268 articles from key journals up to 2024, accurately extracting 124,021 relevant battery-related papers.Additionally, we comprehensively searched through 17,559,750 patent applications and granted patents from the European Patent Office and the United States Patent and Trademark Office up to 2024, from which we filtered out 125,716 battery-related patents. Utilizing this extensive collection of literature and patents, we conducted numerous experiments to evaluate the knowledge base, in context learning, instruction-following, and structured output capabilities of language models. Through multi-dimensional model evaluations and analyses, we found the following: first, the model exhibited high accuracy in screening literature on inorganic solid-state electrolytes, equivalent to the level of a doctoral student in the relevant field. Based on 10,604 data entries, the model demonstrated good recognition capabilities in identifying literature on in-situ polymerization/solidification technology. However, its understanding accuracy for this emerging technology was slightly lower than that for solid-state electrolytes, requiring further fine-tuning to improve accuracy. Second, through testing with 10,604 data entries, the model achieved reliable accuracy in extracting inorganic ionic conductivity data. Third, based on solid-state lithium battery patents from four companies in South Korea and Japan over the past 20 years, the model proved effective in analyzing historical patent trends and conducting comparative analyses. Furthermore, the model-generated personalized literature reports based on the latest publications also showed high accuracy.Fourth, by leveraging the model's iteration strategies, we enabled DeepSeek to engage in self-thinking, thereby providing more comprehensive responses. The research results indicate that language models possess strong capabilities in content summarization and trend analysis. However, we also observed that the model may occasionally exhibit issues with numerical hallucinations. Additionally, while processing vast amounts of battery-related data, the model still has room for optimization in engineering applications. Based on the characteristics of the model and the above test results, we utilized the DeepSeek V3-0324 model to extract data on inorganic solid electrolyte materials, including 5,970 entries of ionic conductivity, 387 entries of diffusion coefficients, and 3,094 entries of migration barriers. Additionally, it includes over 1,000 entries of data related to chemical, electrochemical, and mechanical properties, covering nearly all physical, chemical, and electrochemical properties associated with inorganic solid electrolytes. This also signifies that the application of large language models in scientific research has transitioned from assisting research to actively advancing its development. The datasets presented in this paper can be acess at the website: https://cmpdc.iphy.ac.cn/literature/SSE.html (DOI: https://doi.org/10.57760/sciencedb.j00213.00172).
, , Received Date: 2025-03-11
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With accelerating urbanization, accurately predicting intra-urban population mobility has become a fundamental requirement for urban planning and policy formulation. However, the adaptability and performance of existing mobility models across spatial scales remain unclear, and there is a lack of systematic evaluation frameworks that integrate spatial granularity, travel distance, and population heterogeneity. This study addresses these gaps by proposing a cross-scale comparative framework to evaluate three representative mobility models—the Gravity Model (GM), Radiation Model (RM), and Population-Weighted Opportunities Model (PWO)—under varying urban conditions.We construct three groups of controlled experiments using high-resolution mobile phone data from Shanghai to assess model performance across spatial (grid size), distance, and population density scales. Furthermore, we apply multivariate analysis of variance (MANOVA) to decompose the relative contributions of different spatial factors to prediction errors.The results demonstrate distinct scale sensitivities among the models. The GM model, grounded in Newtonian gravitational principles, shows high robustness over longer distances (>5 km), yet suffers from performance degradation under fine spatial granularity due to spatial heterogeneity. Its accuracy improves with population scale but decreases significantly when regional area disparities exceed a threshold—prediction performance drops by over 40% when grid size differences surpass 3 km. The RM model, based on the nearest-best-opportunity assumption, performs well for short-distance, origin-driven flows, such as commuting, but introduces systematic bias in small-scale contexts. Its sensitivity to origin population density makes it more suitable for high-density urban cores. The PWO model enhances RM by incorporating destination population weights, exhibiting superior compatibility with spatial heterogeneity in dense, polycentric cities. It performs best at short distances (<5 km) but loses effectiveness as travel distance increases.MANOVA results confirm that GM is primarily influenced by population density and area scale, whereas RM and PWO are more sensitive to distance and destination-related factors. Based on these findings, we propose a model selection strategy tailored to mobility drivers: GM is recommended for long-distance prediction in spatially homogeneous regions, while PWO is preferred for short-range flows between small, densely populated areas. RM serves as a complementary model when origin-driven flows dominate.This study not only clarifies the physical mechanisms underlying scale-dependent model performance but also offers an actionable decision-making framework for selecting appropriate models in different urban mobility scenarios. Future research can further improve predictive accuracy by developing hybrid models that combine strengths of multiple frameworks, integrating multi-source spatial data such as POIs and land use, and coupling traditional models with deep learning approaches to enhance non-linear pattern recognition while preserving interpretability. By uncovering the scale-sensitivity of mobility models, this work lays a theoretical and methodological foundation for multi-scenario mobility forecasting in smart city planning and fine-grained urban governance.
, , Received Date: 2025-02-21
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,
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The low-grazing-angle reflection from an elastic sediment seabed exhibits singularly enhanced frequency characteristics, which significantly influence long-range sound propagation in shallow water. To study the influence of elastic sedimentary layer seabed environment on long-range sound propagation in shallow waters, we conducted a joint measurement of seabed and waveguide sound propagation experiment in the Dongsha area of the South China Sea. The experiment recorded the simultaneous occurrence of seabed resonance and the sound siphon effect for the first time. Notably, this effect differs from the sound siphon effect observed in low-sound-speed seabed environments, as it exhibits smaller frequency intervals. By analyzing the low-grazing-angle reflection characteristics of the elastic seabed, we derived a theoretical model for the resonance frequencies of shear waves in elastic sediment layers under small grazing angles and investigated their impact on long-range sound propagation. The results demonstrate that under an elastic seabed model, the low-grazing-angle reflection modulated by shear waves induces resonance at specific frequencies within the sediment layer. This traps acoustic energy in the seabed, leading to the sound siphon effect. Furthermore, we analyzed the sensitivity and coupling of key parameters related to shear-wave resonance frequencies. Based on these findings, we developed an inversion strategy that integrates seabed and waveguide observations to estimate geo-acoustic parameters of the experimental area. The inversion results validate the mechanism by which the elastic seabed model contributes to the sound siphon effect in the water column.
,
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The atomic arrangement of metallic glasses lacks long-range periodicity, displaying structural characteristics of an amorphous state. Their unique structural features lead to research methods that differ from traditional metallic crystalline materials, focusing mainly on two scales: one class at the macroscopic scale investigating glass-forming ability and mechanical behavior through alloy design, thermodynamic parameters, and other means; the other class at the atomic scale studying medium- to short-range orders of metallic glass through computational simulations and diffraction techniques. There is over a seven-order magnitude difference between the scales of these two methods, making it difficult to establish a direct quantitative relationship between the two, necessitating a structural feature that can connect atomic configurations with macroscopic properties at a mesoscopic scale. With the advancement of characterization techniques for amorphous structures, metallic glasses have been found to exhibit nanoscale and microscale spatial heterogeneity above medium- and short-range orders, with their scale falling between macroscopic and atomic scales. This article will introduce experimental characterization methods for spatial heterogeneity, focus on the electron microscopic characterization methods of spatial heterogeneity and local atomic orders, and discuss their intrinsic correlations with macroscopic properties such as β-relaxation behavior, mechanical behavior, thermodynamic stability, and glass-forming ability. As a structural feature of metallic glasses at the mesoscopic scale, spatial heterogeneity can serve as a link connecting the atomic medium- to short-range orders with macroscopic properties.
,
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A dual-parameter sensor based on a symmetrically chirped long-period fiber grating (SCLPFG) is proposed and demonstrated. The SCLPFG consists of two segments of long-period fiber grating (LPFG) of identical length and average period, but with opposite chirp coefficients, resulting in the formation of an in-fiber Mach-Zehnder interferometer (MZI). Due to the chirping effect of the LPFG, the core mode at different wavelengths is coupled to the cladding mode at varying positions within the positively chirped LPFG. Integrated with the symmetry of the SCLPFG, the stimulated cladding mode is recoupled into the core at the symmetrical position in the negatively chirped LPFG. Consequently, in this MZI configuration, the effective length of the interference arm is not fixed but varies with wavelength. As a result, the transmission spectrum of the SCLPFG is characterized by a nonuniform fringe pattern where the free spectrum range (FSR) increases with wavelength. For the MZI-based fiber sensor, the phase difference between the core and cladding modes, influenced by environmental parameters, plays a crucial role in determining sensitivity, as this phase difference is directly proportional to the length of the interference arm. Therefore, the sensitivities interrogated by the dips at different wavelengths in the fringe pattern are inherently different for a specific measurand, leading to the potential for multi-parameter sensing through a differential modulation method.
The fringe characteristics and sensing mechanism are systematically investigated through theoretical analysis and numerical simulation. In the experimental section, the SCLPFG structure was inscribed into a Corning single-mode fiber via point-by-point UV pulse laser irradiation on the photosensitive core. The grating exhibits an average period of 321 μm and a chirping coefficient of ±21.9 μm/cm, with the total length of the symmetrically chirped grating determined to be 4.34 cm. Experimental implementation of simultaneous dual-parameter sensing for surrounding refractive index (SRI) and temperature was conducted, verifying the differential response of distinct fringe dips to SRI and temperature variations. A 2×2 sensitivity coefficient matrix was established by linearly fitting the SRI and temperature response data, which were obtained by interrogating two dips at different wavelengths. Thus, the variations of SRI and temperature were determined based on the inverse sensitivity coefficient matrix multiplied by the wavelength shift array. Furthermore, temperature sensitivities were corrected by accounting for the thermal effect on the liquid refractive index. Finally, the sensor achieved maximum sensitivities of -95.316 nm/RIU for SRI and 0.0849 nm/℃ for temperature, both with excellent linearity. This sensing scheme features a compact structure, high sensitivity, and multi-parameter measurement capability. Moreover, the multi-channel nonuniform fringe characteristics enable the sensor configuration to be extended for simultaneous measurement of three or more parameters, providing a promising lab-on-fiber platform for multi-parameter sensing applications.
The fringe characteristics and sensing mechanism are systematically investigated through theoretical analysis and numerical simulation. In the experimental section, the SCLPFG structure was inscribed into a Corning single-mode fiber via point-by-point UV pulse laser irradiation on the photosensitive core. The grating exhibits an average period of 321 μm and a chirping coefficient of ±21.9 μm/cm, with the total length of the symmetrically chirped grating determined to be 4.34 cm. Experimental implementation of simultaneous dual-parameter sensing for surrounding refractive index (SRI) and temperature was conducted, verifying the differential response of distinct fringe dips to SRI and temperature variations. A 2×2 sensitivity coefficient matrix was established by linearly fitting the SRI and temperature response data, which were obtained by interrogating two dips at different wavelengths. Thus, the variations of SRI and temperature were determined based on the inverse sensitivity coefficient matrix multiplied by the wavelength shift array. Furthermore, temperature sensitivities were corrected by accounting for the thermal effect on the liquid refractive index. Finally, the sensor achieved maximum sensitivities of -95.316 nm/RIU for SRI and 0.0849 nm/℃ for temperature, both with excellent linearity. This sensing scheme features a compact structure, high sensitivity, and multi-parameter measurement capability. Moreover, the multi-channel nonuniform fringe characteristics enable the sensor configuration to be extended for simultaneous measurement of three or more parameters, providing a promising lab-on-fiber platform for multi-parameter sensing applications.
, , Received Date: 2025-03-30
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By numerically solving the static and time-dependent Gross-Pitaevskii equations, we systematically investigate the ground-state properties and collective excitations of a weakly interacting Bose gas with the Raman-type spin-orbit coupling in one dimension. Our analysis focuses on three distinct quantum phases—the stripe phase, plane-wave phase, and zero-momentum phase—characterizing their key static properties, such as condensate momentum, spin polarization, and ground-state energy. Using time-dependent simulations, we explore the dynamics of total-density collective modes, including the dipole mode, which drives harmonic oscillations of the atomic cloud's center of mass, and the breathing mode, responsible for periodic expansion and contraction of the density profile. The modes' frequencies exhibit a non-monotonic dependence on the Rabi frequency across the three phases and are significantly suppressed at the transition point between the plane-wave and the zero-momentum phases. Additionally, we study spin-dependent collective excitations, particularly the spin-dipole and spin-breathing modes, governed by the time-dependent spin density distribution $(\delta n(x, t) \equiv n_\uparrow(x, t)-n_\downarrow(x, t)$) as shown in the following figure. Our results reveal that two spin oscillation modes exist only in the stripe and zero-momentum phases, with frequencies remarkably higher in the latter. Notably, in the stripe phase, mode frequencies decrease monotonically with increasing Rabi frequency, whereas they rise linearly in the zero-momentum phase. The spin-dipole mode induces rigid, out-of-phase oscillations of the two spin components, while the spin-breathing mode modulates the spin density distribution periodically. These findings offer fundamental theoretical insights into the dynamic behavior of spin-orbit-coupled quantum gases, particularly regarding spin-related collective excitations, and provide valuable guidance for future cold-atom experiments.
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We investigate the properties of the color-flavor-locked (CFL) quark matter at finite temperature and under strong magnetic fields within quasiparticle model. Our results indicate that the pressure of CFL quark matter may become anisotropic under strong magnetic fields, and the equations of state (EOS) and the equivalent quark mass can be strongly influenced by the temperature, the energy gap constat Δ, and the strong magnetic fields inside the CFL quark matter. The equivalent quark mass of CFL quark matter decreases with the increment of the temperature and magnetic field strength, which implies a inverse magnetic catalysis phenomenon. The results also indicate that the entropy per baryon of the CFL quark matter increases with the temperature and decreases with Δ. Furthermore, we study the properties of the CFL magnetars in different isentropic stages, and the results indicate that the star mass and radius is mainly dependent on the strength and orientation distributions of the magnetic field inside the CFL magnetars. The maximum star mass increases with the entropy per baryon, and the temperature of the star matter increases at the large isentropic stages. Moreover, our results also suggest that the polytropic index of the CFL quark matter decrease with the increment of the star mass.
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