Search Results (3,773)

Coupling-coordination degree (CCD) indices are often interpreted as evidence that urban systems are developing in a mutually supportive manner. The standard formula, however, combines similarity between subsystem scores with their average level. This article evaluates those two components against the following external outcome: municipal environmental services. A city panel for China in 2002–2024 combines broadband and mobile adoption, urban road provision, licensed internet data-center records, and seven indicators of water, gas, drainage, sewage, waste, and urban greening. The preferred sample contains 6094 observations for 275 cities in 28 provinces. We estimate city fixed-effect models with province-by-year fixed effects and report province-clustered, two-way-clustered, and 9999-repetition wild-cluster-bootstrap inference. In the baseline rank-based construction, a one-standard-deviation increase in relative digital-transport alignment is associated with a 0.046-standard-deviation increase in the environmental-service index (wild-bootstrap p = 0.042), whereas the portfolio-level coefficient is 0.191 (p < 0.001). The alignment estimate is concentrated in water and gas access and is not robust to complete-component outcomes, PCA or entropy weighting, logarithmic standardization, road density, or lags beyond one year. Portfolio level remains positive across these tests, although lead and reverse-direction estimates preclude causal interpretation. The findings show why infrastructure scale, relative configuration, and realized service outcomes should be monitored separately. For SDGs 9 and 11, city governments should target documented service bottlenecks and operating capacity rather than maximize a composite coordination score. Full article

Geopolitical instability can reshape trade routes, prices, and energy-security risks. Using a monthly country-level panel from January 2015 to June 2025, this study estimates a difference-in-differences (DID) model for the logarithm of China’s fossil-fuel import values (USD) from Russia and four Central Asian suppliers relative to seven comparison suppliers. The corrected benchmark coefficient is −0.582. This estimate means that after March 2022, import values from the treated suppliers were lower relative to the counterfactual trend represented by the control group; it does not mean that every treated supplier experienced an absolute decline. Indeed, several country- and commodity-specific import values increased in levels, partly because the outcome combines quantity and price effects. Commodity-specific international price benchmarks are included as controls, but physical-volume data are not available in the submitted dataset. With only 11 country clusters, conventional clustered significance levels are interpreted cautiously. A 500-assignment placebo exercise provides a randomization-based robustness check, with no simulated coefficient as extreme as the benchmark estimate (empirical p ≤ 0.002 under the stated assignment scheme). Logistics performance, government stability, and energy OFDI are positively associated with import values in conditional regressions; because the article does not report interaction terms, these results are not interpreted as moderation effects. The findings support targeted attention to corridor reliability and supplier diversification, while broader operational policies require additional evidence. Full article

Electrochemical impedance spectroscopy (EIS) resolves the internal physicochemical processes of lithium-ion batteries across timescales—from ohmic conduction through charge-transfer kinetics to solid-state diffusion. Despite this analytical power, EIS deployment remains largely confined to laboratory electrochemical workstations that are bulky, expensive, and incapable of online multi-cell operation under dynamic DC bias conditions. This study presents a multi-channel EIS measurement device that simultaneously addresses three requirements for practical battery diagnostics: workstation-grade measurement accuracy, multi-cell synchronous acquisition, and tolerance to the DC bias voltage present across battery terminals during operation. The device employs a master–slave distributed architecture: each slave unit is built around the DNB1101 battery-dedicated impedance measurement chip with a Kelvin four-wire sensing configuration, while the STM32F407-based master controller coordinates measurement scheduling and data communication under FreeRTOS. A four-channel slave board with a differential daisy-chain communication topology and hardware broadcast trigger mechanism supports multi-cell synchronous acquisition. The device operates over a frequency range of 0.01 Hz to 5620 Hz with logarithmic spacing, and a C#-based host application provides real-time Nyquist and Bode visualization along with MATLAB R2024a-based post-processing for outlier rejection and data smoothing. Validation was conducted using Panasonic NCR18650 ternary (NCA) and LiFePO₄ (LFP) 18650 cells, benchmarked against a CorrTest CS350 electrochemical workstation at SOC = 40% and 25 °C. The device achieves a maximum impedance magnitude error of 1.55% and a maximum phase error of 1.22%. Equivalent circuit model fitting via ZSimpWin yields parameter differences below 1% between the device and the reference workstation. Under online conditions with a 3.6 V DC bias, the impedance measurement deviation of a 20 mΩ precision resistor remains below 0.69% across the full frequency range. Multi-channel synchronous measurements across four cells demonstrate inter-channel amplitude variance below 2.13%. Cross-chemistry validation with LiFePO₄ cells yields magnitude and phase errors below 0.92%. These results demonstrate that the proposed device provides laboratory-grade EIS accuracy with multi-channel, online, and cross-chemistry capabilities, offering a practical platform for integrating EIS-based diagnostics into next-generation battery management systems. Full article

Optical coherence tomography (OCT) is a high-resolution and non-contact optical imaging and sensing modality that provides depth-resolved cross-sectional visualization of retinal microstructures. It plays an important role in the assessment of retinal diseases, including age-related macular degeneration (AMD) and diabetic macular edema (DME). However, automated OCT image classification commonly relies on fully supervised models that require large-scale expert annotations, which are costly and time-consuming because of the complex layered anatomy and subtle pathological patterns present in retinal OCT images. To reduce annotation dependence, this study proposes a self-supervised representation learning framework with local dimensionality regularization for retinal OCT image classification. The proposed method estimates the local intrinsic dimensionality of learned representations and incorporates it into an asymptotic Fisher-Rao regularization objective to mitigate local dimensional degeneration and preserve fine-grained structural information. Logarithmic scaling and geometric averaging are further introduced to reduce sensitivity to outliers and improve optimization stability. Experiments on three independent OCT datasets achieved classification accuracies of 94.35%, 92.48%, and 92.56%, respectively, demonstrating competitive performance compared with mainstream self-supervised methods. These results demonstrate that explicitly modeling local feature geometry can improve the discrimination of sensor-acquired OCT images while reducing reliance on manual annotations, providing an effective approach for intelligent analysis of biomedical optical imaging data. Full article

The fine-structure constant is an empirical boundary datum of quantum electrodynamics (QED), not a value derived by the Standard Model. We give a conditional structural derivation in which its inverse is matched to the response capacity of a neutral codimension-two holonomy defect. The Indefinite Reconstruction Stability Principle and the topology of a punctured transverse space select codimension two and an integer winding group $\mathbb{Z}$. Phase and spin read-outs are represented by native norm-one groups $\mathrm{U}\left(1\right)$ and $\mathrm{SU}\left(2\right)$. Preserving their algebraic identities and multiplicative norms fixes the measures $2\pi$ and $2{\pi }^2$. Their three nonempty exposures have total capacity $\Omega =4{\pi }^3+{\pi }^2+\pi$. Four first-interface roles and one protected identity select $\mathbb{Z}/5\mathbb{Z}$; its 24 nonzero outgoing–returning state pairs form one symmetry orbit, fixing the first correction. At later resolutions, a separately declared asymmetric complete-source/exposed-target transfer rule—not the Chinese remainder theorem used only for common refinement—fixes the coefficients by unit counting without assuming composite-level transitivity. With a declared paired-interface grading rule, they yield an absolutely convergent odd-power tower with an exact logarithmic sum. A separate low-energy QED matching postulate identifies the structural response with the renormalized zero-momentum Maxwell coefficient, giving $\alpha {\left(0\right)}^{-1}=137.035999176142$, $0.041$ standard deviations below the 2022 CODATA value. No numerical coefficient is adjusted once the declared read-out, counting, transfer, grading, and matching assumptions are fixed. The construction does not derive QED dynamics or the running coupling. Full article

Wind is an important abiotic factor that may influence predator–prey interactions. In this paper, we propose and analyze a stochastic predator–prey model in which the predator attack rate is described by a unimodal function of a fixed wind-intensity index. We establish the global existence, uniqueness, and positivity of solutions, together with stochastic ultimate boundedness, and derive a sufficient condition for the existence of a unique ergodic stationary distribution. A key analytical feature is that the Foster–Lyapunov recurrence argument is completed without quadratic predator self-limitation by exploiting the negative contribution generated by linear predator mortality. The resulting condition $\lambda >0$ incorporates effective predation, density dependence, wind modulation, predator mortality, and population-level environmental noise, and is a sufficient rather than necessary condition. Numerical parameter sweeps based on the complete expression for $\lambda$ and simulations using a logarithmic Euler–Maruyama scheme illustrate parameter-specific changes in the sufficient-condition quantity and in the post-burn-in empirical population distributions. Full article

Authenticated key exchange has been built for decades on a small number of hard mathematical problems, and the elliptic curve discrete logarithm is one of them. The structural complexity of biological macromolecules, however, has rarely been used as a source of secret material in such protocols. In this paper, a protein-derived authenticated key exchange protocol, called PDKE-2, is proposed to address this gap. The protocol keeps elliptic curve Diffie–Hellman at its core and adds two ingredients from structural biology. Firstly, a per-session base point G* is generated by applying RFC 9380 hash-to-curve to a session mapping table. Secondly, a long-term secret shared between the two parties is derived from the SHA-256 digest of an AlphaFold2 inter-residue distance matrix. In contrast to an earlier version of this design, the two parties run ephemeral Diffie–Hellman in each session and the session key is never sent over the channel; only transcript-based confirmation tags are exchanged. Thus, the protocol provides forward secrecy and avoids a confidentiality weakness that existed in the earlier version. The security of PDKE-2 is analysed in the Real-or-Random model, where session key secrecy, forward secrecy and mutual authentication are proved under the Gap Diffie–Hellman, PRF-HKDF and EUF-CMA-HMAC assumptions. In addition, the protocol is modelled in ProVerif against a Dolev–Yao attacker, and the secrecy of the session key, the secrecy of the shared secret and the injective agreement in both directions are all confirmed. A Python reference implementation is also provided. In the implementation, key agreement and mutual authentication succeed in every session, and the complete handshake takes about 15 ms in the reference code. It should be noted that the protein layer does not increase the elliptic curve security level; it works as an authentication secret whose strength depends on the difficulty of guessing the protein sequence when this sequence is kept private. Full article

To address the critical challenge of extracting short-period surface deformation signals induced by extreme floods from InSAR time series, this study focuses on the catastrophic flood that struck the Haihe River Basin in July 2023 (hereinafter referred to as the “23·7” flood, with a total duration of approximately 65 days) and proposes a novel method for transient deformation signal extraction. Using Sentinel-1A satellite data and the PS-InSAR technique, we constructed a multivariate composite fitting function comprising a linear trend term, annual and semi-annual seasonal terms, a step term, and a logarithmic decay term. Through nonlinear least-squares fitting, this approach achieves effective separation of long-term tectonic deformation, seasonal fluctuations, high-frequency noise, and transient flood-related signals. The results show that the W-shaped floodplain east of Xiong’an New Area does not exhibit the expected subsidence induced by water loading but instead features pronounced surface uplift of up to 30 mm. Multi-physics forward modeling reveals the underlying mechanism: the elastic subsidence caused by surface water loading, calculated via the LoadDef spherical loading theory, amounts to only ~2 mm. In contrast, forward modeling based on the GMS three-dimensional groundwater seepage model and the principle of effective stress indicates that the pore water rebound effect can produce surface uplift of up to ~36 mm. The superposition of these two effects is highly consistent with InSAR observations in terms of magnitude, direction, and spatial distribution, confirming that the flood-induced surface deformation is dominated by the pore water rebound effect driven by rapid groundwater recharge, rather than subsidence from water loading. The proposed framework extends the application potential of geodetic techniques for monitoring short-period extreme hydrological events. Full article

Against China’s dual carbon peaking and carbon neutrality strategic goals, nationwide digital transformation brings both carbon abatement dividends and potential energy rebound risks, and its full low-carbon potential is constrained by local industrial foundations and regional economic development stages. Most existing studies merely treat industrial upgrading as an intermediate transmission channel, with little discussion of its moderating influence. Moreover, few threshold analyses take the comprehensive level of regional economic development as the core threshold variable to capture the boundary conditions of digital decarbonization effects. Based on balanced panel data covering 30 provincial-level regions of China from 2011 to 2023, this paper constructs a multi-dimensional digital economy index via the entropy weight method. Prior to formal regression, we conduct Pearson correlation analysis and mean-centered VIF multicollinearity diagnostics to avoid biased estimation. Two-way fixed-effects regression, moderation tests, Bootstrap-based regional heterogeneity comparison and Hansen’s single threshold model are adopted for empirical analysis. The results show that digital economy development significantly curbs carbon emission intensity; a one-standard-deviation increase in the digital economy composite index is associated with an approximately 9.7% decline in carbon emission intensity. The mean-centered interaction term DIG × UIS is significantly negative at the 1% level, proving that service-oriented industrial upgrading strengthens the carbon reduction effect of digitalization. The mitigation effect displays distinct spatial divergence: the estimated coefficient equals −2.638 for eastern provinces, −3.585 for central regions and −1.700 for western areas. Bootstrap inter-group coefficient tests confirm statistically significant gaps between east–west and central–western subgroups. Threshold regression identifies a single threshold of logarithmic per capita GDP at 11.94. After crossing this economic development threshold, the inhibitory coefficient of the digital economy rises markedly from −0.844 to −1.473. This study enriches the theoretical system of digital low-carbon transition by jointly uncovering the moderating role of industrial upgrading and the stage threshold constraint of economic development and offers differentiated digital low-carbon policy guidance for provincial governments. Full article

This paper focuses on three finite difference schemes for the interval advection equation based on a novel interval calculus framework. Different from classical interval arithmetic, this innovative framework equips the interval number space with a rigorous Hilbert space structure and enables a critical decoupling of the derivative for interval-valued functions, where the center component obeys classical differentiation rules and the radius component complies with multiplicative differentiation principles. Using this unique decoupling property, we construct interval counterparts of three representative classical finite difference schemes, namely the Upwind, Lax–Friedrichs, and Lax–Wendroff schemes, and conduct a comprehensive and rigorous theoretical assessment of their numerical properties. Utilizing the inherent isometric isomorphism between the interval space and ${\mathbb{R}}^2$, we rigorously establish the consistency of the proposed schemes and adopt the von Neumann method for systematic stability analysis. A sharp, explicit Courant–Friedrichs–Lewy (CFL) condition is derived, which jointly accounts for the center velocity and logarithmic radius velocity of the interval advection field, and the scheme convergence is strictly guaranteed via the Lax equivalence theorem. Extensive numerical experiments are carried out to validate the theoretical conclusions and verify the practical merits of the developed interval schemes. The numerical results demonstrate that the proposed methods retain nearly constant interval width in long-duration simulations, completely bypass the switching-point complexity that intrinsically exists in traditional generalized Hukuhara (gH)-based interval approaches, and deliver competitive computational efficiency. This work corroborates that the newly proposed interval calculus framework serves as an elegant, solid, and versatile foundation for the numerical computation and analysis of interval partial differential equations. Full article

Closed-form Caputo gradients in critical-state stress-fractional plasticity have relied on the polynomial Modified Cam-Clay surface. We extend them to the non-polynomial teardrop bounding surface by defining the operator as a Caputo derivative in the logarithm of normalized pressure, orientation-corrected for that decreasing map. On this axis, the surface becomes power–exponential, its critical-state terminal falls at exactly t* = 1/Ψ independently of Ω, and the fractional gradient reduces to incomplete-Beta–Kummer and Humbert-Φ₁ closed forms, verified against singularity-aware quadrature over 1240 cases to relative errors below 10⁻¹¹. The flow rule recovers associated flow as α → 1 and is exactly associated at the critical state. This is a computational study of operator semantics on inherited calibrations, not an experimental validation. Substituting it for the fixed-window Grünwald–Letnikov flow of a companion factorial collapses the dominant flow main effect from −60% to below 0.2% for both clays at every overconsolidation ratio tested, across drained and approximately undrained paths. The collapse is conditional: it is a property of the critical-state dwell, and at a laboratory-scale budget the operators still differ by about 15% of baseline. Window semantics, not fractionality alone, decide where flow influence resides in a factorial design. Full article

This study employed sequential inoculation of native non-brewing yeasts Kluyveromyces marxianus YC-T7 and Pichia kudriavzevii QC-P3 to co-ferment dry white wine from Munage, a unique fresh-eating grape variety native to Xinjiang, providing technical support for the development of regionally distinctive wines in Xinjiang. To investigate how mixed fermentation with indigenous Xinjiang non-Saccharomyces (NS) yeasts and Saccharomyces cerevisiae (SC) influences the aromatic profile of Munage wine, two NS strains—K. marxianus YC-T7 and P. kudriavzevii QC-P3—previously isolated and selected by our group were sequentially co-inoculated with S. cerevisiae CEC01. Strain growth dynamics were first characterized in a synthetic grape juice (SGJ) system under varying inoculation protocols; subsequently, Munage grapes were fermented under optimized sequential inoculation to assess physicochemical parameters, volatile aroma composition, and sensory attributes of the resulting dry white wine. Results demonstrated that, under sequential inoculation, the QC-P3 + SC consortium entered the late logarithmic phase on day 4 and achieved a final ethanol concentration of 10.29%vol, whereas the YC-T7 + SC consortium reached the same growth stage on day 5 with 10.27%vol ethanol—confirming robust and timely alcoholic fermentation for both consortia. Consequently, sequential inoculation was adopted as the standard protocol for Munage wine production. All key physicochemical parameters complied with China’s national standards for dry white wine. Relative to pure SC fermentation, the YC-T7 + SC treatment increased tartaric acid, α-ketoglutaric acid, and citric acid contents by 3.15%, 12.16%, and 2.18%, respectively; the QC-P3 + SC treatment induced more pronounced enhancements—22.58%, 51.64%, and 14.70%, respectively. A total of 54 volatile compounds were identified, including 29 esters, 12 alcohols, 7 organic acids, 4 phenolic compounds, and 2 others. Integrated analysis using odor activity values (OAVs), principal component analysis (PCA), and descriptive sensory evaluation consistently revealed that the YC-T7 + SC wine exhibited the highest concentrations of fruit- and flower-associated esters, while the QC-P3 + SC wine was distinguished by a distinctive pineapple-like aroma driven predominantly by ethyl butyrate. Collectively, sequential co-inoculation of indigenous Xinjiang NS strains YC-T7 and QC-P3 with S. cerevisiae significantly improved Munage wine quality—particularly in acidity balance, polyphenol retention, and aromatic complexity—thereby offering both novel microbial resources and a validated technical framework for stylistically authentic vinification of terroir-expressive wines from the Xinjiang region. Full article

This paper presents the next stage of research on epoxy-glass composites modified with carbonisate obtained from the pyrolysis of waste MDF boards. Previous studies focused on assessing the mechanical properties of the developed material, while the aim of this work was to expand its characterization to include assessment of electrical properties and to determine the potential use of carbonisate as a functional filler in electrically insulating composites. The effect of carbonisate particle size (<500, <1000, and <1500 µm), carbonisate content (5% and 7.5% by weight), and resin-to-reinforcement ratio on the surface and volume resistivity of epoxy-glass composites was analysed. The microstructure of the materials was assessed using optical microscopy and scanning electron microscopy (SEM). To quantitatively assess changes in electrical insulating properties, we used logarithmic resistivity analysis and our own dielectric destabilization index (D), which serves as a comparative engineering index. The obtained results showed that increasing the carbonisate particle size leads to a gradual decrease in the electrical insulating properties of the composites and an increase in their structural heterogeneity. The highest dielectric destabilization index value was obtained for the composite containing 7.5% carbonisate with a fraction <1500 µm (D = 0.403). Microstructural observations confirmed the presence of agglomerates, micropores, and local structural discontinuities, which can reduce the electrical resistivity of the tested materials. The conducted studies confirmed the possibility of using carbonisate obtained from waste MDF (Medium-Density Fibreboard) boards as a functional filler in epoxy-glass composites. The obtained results constitute the next stage of comprehensive characterization of the developed material and indicate that the appropriate selection of the carbonisate morphology and the composition of the composite may enable shaping its electrical insulating properties depending on the planned application. Full article

Antibiotics are the primary treatment for bacterial respiratory diseases in ruminants. Mannheimia haemolytica is the major etiological agent causing respiratory diseases in ruminants, but its tolerance to antibiotics remains poorly understood. In this study, strains of M. haemolytica belonging to the main serotypes A1, A2, and A6 were selected for analysis of their ability to form multidrug-tolerant persister cells. The results showed that M. haemolytica was able to form approximately 10⁴ CFU/mL of antibiotic-tolerant persisters during both the logarithmic phase and the stationary phase. Compared to the logarithmic phase, the ability of stationary phase cells to form persisters was significantly enhanced. Further analysis revealed that different stress conditions had varying effects on the ability of the three serotype strains to form persister cells. Under low dissolved oxygen conditions, the ability of the three serotype strains to form multidrug-tolerant persisters was significantly weakened. Oxidative stress conditions exerted the greatest effect on persister formation in the serotype A2 strain QS2-1, whereas acid stress had the greatest impact on persister formation in the serotype A6 strain Mh1128. Finally, strategies for the eradication of M. haemolytica persister cells were examined. The use of antibiotic combinations with distinct mechanisms of action can effectively and rapidly reduce the formation of persister populations in certain strains under our experimental conditions. Furthermore, L-Serine and mannitol were shown to enhance the susceptibility of most strains to florfenicol. Overall, this study examined the capacity of M. haemolytica to form persisters and explored the factors influencing the formation of these persisters, as well as potential strategies for their eradication. The findings offer a theoretical foundation for the treatment of M. haemolytica respiratory infections in ruminant species. Full article

This study presents a performance-based forensic investigation of the Tanada wall, a geosynthetic reinforced soil wall with a full-height rigid facing that experienced strong shaking during the 1995 Hyogoken Nambu earthquake in Japan. The analytical framework integrates a compiled soil stress–displacement dataset, limit equilibrium constraints, displacement-based back analysis, reconstruction of the displacement (Δ_3h)–seismic inertial coefficient (k_h) curve, and systematic parameter sensitivity evaluation. The displacement-based seismic resistance curves developed using representative soil parameters show that the Tanada wall maintains strong seismic resistance up to HPGA ≈ 0.7–0.8 g, with displacement trends that remain physically consistent across three logarithmic cycles. Sensitivity analyses demonstrate that only three parameters—the soil stiffness number K, peak friction angle φ_peak, and the initial pullout stiffness number K_t—produce variations of approximately ±0.8–1.5 × 10⁻³ m in the final displacement Δ_3h. All remaining soil, reinforcement, and facing parameters contribute only minor variations on the order of a few 10⁻⁴ m. These findings show that the force-equilibrium-based finite displacement method (FFDM), supported by laboratory evidence and displacement-based inference, provides a rigorous and physically grounded methodology for forensic evaluation of reinforced soil structures. Full article