Evolution Of Coupling Research Articles

JWST observations constrain the time evolution of fine structure constants and dark energy-electromagnetic coupling

Abstract It was hypothesized in the literature that some physical parameters may be time-evolving and the astrophysical data can serve as a probe. Recently, James Webb Space Telescope (JWST) have released its early observations. In this work, we select the JWST spectroscopic observations of the high redshift ($z>7.1$) galaxies with strong [\ion{O}{III}] ($\lambda=4959$\AA \,and $5007$\AA \,in the rest frame) emission lines to constraint the evolution of the fine structure constant ($\alpha$). With the spectra from two galaxies at redshifts of $7.19$ and $8.47$, the deviation of $\alpha$ to its fiducial value is found to be as small as $0.44^{+8.4+1.7}_{-8.3-1.7} \times 10^{-4}$ and $-10.0^{+18+1.5}_{-18-1.5} \times 10^{-4}$, respectively (the first error is statistical and the latter is systematic). The combination of our results with the previous data reveals that $\frac{1}{\alpha} \frac{d \alpha}{dt} = 0.30^{+4.5}_{-4.5} \times 10^{-17}~{\rm yr^{-1}}$. Clearly, there is no evidence for a cosmic evolution of $\alpha$. The prospect of further constraining the time evolution of $\alpha$ is also discussed. The scalar field of dark energy is hypothesized to drive the acceleration of the universe's expansion through an interaction with the electromagnetic field. By integrating the observational data of the fine-structure constant variation, $\frac{\Delta\alpha}{\alpha}(z)$, we have established a stringent upper limit on the coupling strength between dark energy and electromagnetism. Our analysis yields $\zeta \leq 3.92 \times 10^{-7}$ at the 95\% confidence level, representing the most stringent bound to date.

The gauge coupling evolutions of an SU(8) theory with the maximally symmetry breaking pattern

We study the renormalizable group equations (RGEs) of the extended strong and weak gauge couplings in an SU(8) theory, where three-generational SM fermions are non-trivially embedded. This framework was previously found to generate the observed SM quark/lepton mass hierarchies and the Cabibbo-Kobayashi-Maskawa mixing pattern through its maximally breaking pattern. The field theoretical two-loop RGEs can not achieve the gauge coupling unification with the minimal setup, unless additional adjoint Higgs fields as well as the gravity-induced d = 5 term to the SU(8) field strength term are included.

Coupled evolution of basin structure and fluids recorded by microfractures: A case study of deep-buried ordovician in the tarim basin

The fluid activity in the deep strata of sedimentary basins is commonly related to tectonic activity, and the cements filled in fractures are a good carrier for the tectonic-fluid coupling evolution. Compared to macrofractures, microfractures have characteristics of high frequency and easy identifiable periods. Abundant microfractures infilled by carbonate cements (MCCFs) developed in carbonates of the Ordovician Yingshan and Yijianfang formations in the platform basin area of the Tarim Basin. Based on the study of petrology, U-Pb dating, and geochemical characteristics, this study determined the stages of MCCFs and clarified the tectonic-fluid coupling evolution process recorded by MCCFs in the study area. The formation order of these MCCFs is D1, C1, C2, D2, C3, and C4. The precipitation times of MCCFs have a good correspondence with orogeny around the Tarim Basin and active times of strike-slip faults in the platform basin area. The six stages of MCCFs in the Ordovician Yingshan and Yijianfang formations in the SLU recorded the tectonic-fluid coupling evolution process of concentrated seawater in the late Middle Ordovician, meteoric water at late Ordovician, organic acids during the Silurian, Mg-rich hot brine at the end Devonian-early Carboniferous, and magmatic hydrothermal fluids during the Permian. This not only indicates a close connection between fluid activity and tectonic activity in sedimentary basins, but also confirms that the formation of MCCFs in carbonate formations is closely related to regional tectonic-fluid coupling activities. This study provides a good example for studying macro scale tectonic-fluid coupling activities in basins using microfractures.

Rationally Designed Mo/Ru-Based Multi-Site Heterogeneous Electrocatalyst for Accelerated Alkaline Hydrogen Evolution Reaction.

The rational design of multi-site electrocatalysts with three different functions for facile H2O dissociation, H-H coupling, and rapid H2 release is desirable but difficult to achieve. This strategy can accelerate the sluggish kinetics of the hydrogen evolution reaction (HER) under alkaline conditions. To resolve this issue, a Mo/Ru-based catalyst with three different active sites (Ru/Mo2C/MoO2) is rationally designed and its performance in alkaline HER is evaluated. The experimental results and density functional theory calculations revealed that, at the heterogeneous Mo2C/MoO2 interface, the higher valence state of Mo (MoO2) and the lower valence state of Mo (Mo2C) exhibited strong OH- and H-binding energies, respectively, which accelerated H2O dissociation. Moreover, the interfacial Ru possessed an appropriate hydrogen binding energy for H-H coupling and subsequent H2 evolution. Thus, this catalyst significantly accelerated the Volmer step and the Tafel step and, consequently, HER kinetics. This catalyst also demonstrated low overpotentials of 19 and 160mV at current densities of 10 and 1000mA cm-2, respectively, in alkaline media and long-term stability superior to that of most state-of-the-art alkaline HER electrocatalysts. This work provides a rational design principle for advanced multi-site catalytic systems, which can realize multi-electron electrocatalytic reactions.

Electromechanical coupling optimization for a sandwich beam activation using piezoceramics

Sandwich beams composed of two stiff carbon fiber skins and a viscoelastic core are often used to passively dissipate energy through the activation of shearing in a specific frequency range. Semi-active or active energy dissipation can be made possible on those structures adding piezoelectric patches, coupling mechanical vibration energy and electrical energy. J.L. Guyader et al. [jsv, 1978] theorized a frequency dependent equivalent dynamic model of a sandwich structure, recently extended to the homogenization of anisotropic multi-layers by F.Marchetti et al. [jsv, 2020]. This frequency-dependent stiffness of the beam has to be taken into account in the piezoceramic thickness definition in order to optimize the global electromechanical coupling coefficient. An analytical model is derived from the works of F.Marchetti et al. and adapted to predict the first vibration mode of a finite cantilever beam instrumented with a piezoelectric patch. The electromechanical coupling evolution is then calculated with the proper boundary conditions and for different PZT ceramic thicknesses. This model is furtherly used to define the best transducer configuration for a given sandwich structure beam.

Analyzing and predicting the urbanization and ecological resilience coupling and coordination of Guangdong Province

Taking 21 cities in Guangdong Province as the research object, this study quantitatively analyzes the spatiotemporal evolution of urbanization and ecological environment coupling from 2000 to 2020 using a coupling coordination model, and predicts the coordinated development of urbanization and ecological resilience coupling from 2000 to 2020 using an LSTM deep learning model. Analysis of the geographical data conveys the following observations: (1) Remotely sensed night-time luminosity data indicate a precipitous escalation in the urbanization quotient within Guangdong, with the Pearl River Delta, featuring Guangzhou and Shenzhen as hubs, exhibiting high levels of nocturnal radiance, in stark contrast to the lower and more dispersed illumination in the province’s northern latitudes. (2) Indices of ecological resilience suggest a progressive enhancement across Guangdong, with Maoming exhibiting the utmost resilience, succeeded by Jiangmen, Dongguan, Shenzhen, and Zhongshan in terms of ecological robustness. (3) The synergistic relationship between urbanization dynamics and ecological resilience metrics in Guangdong has been incrementally enhanced, with Qingyuan and Shaoguan exemplifying optimal coupling and coordination, while Zhongshan has experienced the most pronounced increment in these interdependencies. (4) The proportional advancement of urbanization and ecological resilience in the province is approaching a theoretical equilibrium state. (5) Projections based on spatiotemporal models forecast a gradual upgrade in the urban-ecological systems’ coupling and coordination coefficients from 2021 to 2025, with a general trend of incremental progression among the majority of the province’s urban centers towards a moderate level of integrated development.

Defects trigger redox reactivities between metal and lattice oxygen in high-entropy layered double hydroxide for boosting oxygen evolution in alkaline

The oxygen evolution reaction (OER) at the anode undergoes a sluggish multi-step process, thereby impeding overall water splitting. As the classical adsorbate evolution mechanism (AEM) involves multiple oxygen-containing intermediates, such as *OH, *O and *OOH, breaking the linear relationship of the adsorption energies between *OH and *OOH is the key to efficient oxygen evolution. Herein, we report a high-entropy FeCoNiAlZn layered double hydroxide decorated with defects (E-FeCoNiAlZn LDH) for boosting oxygen evolution in alkaline. The product exhibits high OER activity with a low overpotential of 220 at 10 mA cm−2 and outstanding stability with negligible decline after 100 h operation. The defects in E-FeCoNiAlZn LDH not only enhance the adsorption of *OH by metal sites but also foster the release of oxygen from lattice, which triggers the coupled oxygen evolution mechanism (COM). This mechanism has only *OH and *OO intermediates, perfectly avoiding the obstacles of linear relationship between *OH and *OOH. Theoretical calculations demonstrate that the introduction of defects enhances the adsorption of *OH due to the presence of unsaturated bonds. Additionally, it is evidence that the O 2p band is elevated, leading to a weakening of the metal-O bond and a reduction of the energy barrier for OO coupling.

Research on the Coupled Evolution Relationship Between Digital Economy and Regional Sustainable Development

Research on the Coupled Evolution Relationship Between Digital Economy and Regional Sustainable Development

Coupled Disk-star Evolution in Galactic Nuclei and the Lifetimes of QPE Sources

A modest fraction of the stars in galactic nuclei fed toward the central supermassive black hole (SMBH) approach on low-eccentricity orbits driven by gravitational-wave radiation (extreme mass ratio inspiral (EMRI)). In the likely event that a gaseous accretion disk is created in the nucleus during this slow inspiral (e.g., via an independent tidal disruption event (TDE)), star–disk collisions generate regular short-lived flares consistent with the observed quasiperiodic eruption (QPE) sources. We present a model for the coupled star-disk evolution, which self-consistently accounts for mass and thermal energy injected into the disk from stellar collisions and associated mass ablation. For weak collision/ablation heating, the disk is thermally unstable and undergoes limit-cycle oscillations, which modulate its properties and lead to accretion-powered outbursts on timescales of years to decades, with a time-averaged accretion rate ∼0.1Ṁ Edd. Stronger collision/ablation heating acts to stabilize the disk, enabling roughly steady accretion at the EMRI-stripping rate. In either case, the stellar destruction time through ablation, and hence the maximum QPE lifetime, is ∼102–103 yr, far longer than fallback accretion after a TDE. The quiescent accretion disks in QPE sources may at the present epoch be self-sustaining and fed primarily by EMRI ablation. Indeed, the observed range of secular variability broadly matches those predicted for collision-fed disks. Changes in the QPE recurrence pattern following such outbursts, similar to that observed in GSN 069, could arise from temporary misalignment between the EMRI-fed disk and the SMBH equatorial plane as the former regrows its mass after a state transition.

Coordination analysis and evaluation of population, water resources, economy, and ecosystem coupling in the Tuha region of China

The non-coordination between the socio-economic systems and ecosystems of a region is a crucial obstacle to sustainable development. To reveal the relationships between complex urban systems and achieve the goal of sustainable and coordinated urban development, we constructed a coupling coordination degree model (CCDM) and coupling angle model (CAM) and analyzed the degree of coupling coordination and evolution process among the population, water resources, economy, and ecology (PWEE) system of the Tuha region for 2005–2020. The results indicated that: (1) During 2005–2020, the comprehensive development index (CDI) of the population, water resources and economy subsystems was 0.21–0.65, with the three subsystems portraying an overall increase; the average values of the RSEI at five-year intervals were 0.29, 0.28, 0.28, and 0.26, indicating a downward trend in the environmental quality. (2) The coupling coordination effect of the PWEE system portrayed a low level; the coupling coordination degree (CCD) values were 0.28–0.58, portraying a fluctuating upward trend. The level of CCD increased from low disorder to marginal coordination. (3) The PWEE system’s scissor difference reflects large evolutionary characteristics. The ecological support capacity was not observed until the late stage. We conclude that the PWEE composite system of the region is in a stage of disordered development. These findings significantly bolster the theoretical underpinnings of sustainable development studies, offering essential scientific theories and methodological frameworks for crafting sustainable development policies tailored to urban systems in the Tuha region.

Research on coupling coordination and spatial-temporal evolution of hydrogen energy industry in hebei province based on R-P-D chain

In order to promote the sustainable development of the hydrogen energy industry in Hebei Province, this paper investigates the coordinated industrial coupling and spatio-temporal evolution of the "resource conditions-project layout-user demand (R-P-D)" chain within the hydrogen energy industry in Hebei Province. First, a fitness model for the hydrogen energy industry is formulated based on the "(R-P-D)" chain perspective, and a comprehensive evaluation is performed using the AHP entropy weighting method.Subsequently, coupling coordination model of resource condition-project layout (R–P), resource condition-user demand (R-D), project layout-user demand (P-D), and R-P-D chain are constructed. The coupling coordination degree data of the system are then linked with the spatial unit for spatiotemporal evolution and analysis using ArcGIS software. The findings indicate that cities with high levels of economic development, advanced industrialization, abundant renewable energy resources, and well-developed clean energy industries tend to exhibit more harmonious development in the hydrogen energy industry.

Quantitative assessment method of thermal cycle accumulation mechanism during the pulsed laser single-channel multilayer cladding process

Pulsed laser cladding provides a periodical thermal accumulation, enabling a greater temperature gradient and cooling rate inside the substrate, which can efficiently ameliorate the microstructure of the cladding layer. It is crucial to quantitatively investigate the mechanism of the interaction for the cladding process parameters on the transient evolution of the multi-field coupling to improve the cladding quality. In this paper, a 3-D model during the single-channel multilayer pulsed laser cladding process was constructed which is grounded on the temperature-variable physical properties parameters of the material. The integrated consideration in the masking impact of the molten powder waist beam on the pulsed laser beam, the molten pool liquid metal surface tension, the influence of buoyancy on the flow, and the transient evolution of the molten pool edge morphology. The temperature, flow, and stress fields of the single-channel multilayer cladding process were computed and resolved. The mechanism in multi-field coupling impact of laser pulse frequency, laser power, and pulse duty cycle on the single-channel multilayer cladding process was emphasized. The response surface equations between each influencing factor and the cladding temperature, temperature change gradient, and thermal stress were determined according to the response surface method, and the sensitivity of each parameter was attained from the Monte Carlo method. Using SEM to observe the profile and microstructure of the cladding layer, the material hardness distribution was measured experimentally, and the effectiveness of the model was confirmed. This research supplies an essential rationale for upgrading the quality of pulsed laser cladding layers.

Coupled Simultaneous Evolution of Policy, Enterprise Innovation Awareness, and Technology Diffusion in Multiplex Networks

This study comprehensively examines the coupling effect of government policies, enterprise behavior, and existing technology on the diffusion of innovative technology. Utilizing multiplex network theory, a multiplex network model is constructed to couple policy incentives, enterprise innovation consciousness, and technology diffusion. Both global- and local-order parameters are introduced to characterize the interaction mechanisms between new and old technologies. By employing the microscopic Markov chain approach (MMCA), the threshold for technology diffusion is derived, theoretically revealing the mechanisms behind the diffusion of innovative technology. Considering the heterogeneity of enterprises, a numerical simulation is conducted on a scale-free network. The results indicate that, as the intensity of policy incentives increases, the threshold for technology diffusion decreases, promoting the spread of innovative technology. Additionally, the coupling relationship between existing technology and innovative technology influences the diffusion scale of the latter. The innovation behavior of enterprises further facilitates the adoption and dissemination of innovative technology.

Coupled diffusion law of windflow-gas-dust in tunnel energy extraction processes and the location of optimal pollution control exhaust duct

Coal resources play an important role in the world's energy development. China's coal consumption in 2022 was as high as 88.41 EJ. However, the process of energy extraction generates dust and gas, which is a serious threat to efficient production and workers' health. More than 7000 new cases of pneumoconiosis are diagnosed in China each year. To improve this situation, numerical simulation experiments were used to obtain the coupling diffusion law of airflow-gas-dust during tunnel excavation under long-pressure short-extraction ventilation and to determine the optimal distance of the exhaust duct from the working face (LE) for the purpose of cleaner production. Our experimental results demonstrated that the spatial and temporal evolution of gas-dust coupling largely depends on the distribution of the airflow field. By comparing the concentration distribution of gas and dust at different distances from the working face, the average gas concentration in the tunnels was found to be low (0.249 %) when LE=4m. Furthermore, the average dust concentration in the tunnel was the lowest (242.5 mg/m3) and therefore the least harmful to workers. The optimal exhaust duct distance was LE=4m, which not only reduces the environmental pollution in a tunnel but also ensures the occupational health of workers.

Investigating the Creep Damage and Permeability Evolution Mechanism of Phyllite Considering Non-Darcy’s Flow

This study investigates the intricate interplay of hydraulic coupling, creep damage, and permeability evolution mechanisms in phyllite, focusing on their relevance to tunnel engineering design and long-term stability in soft rock formations. To achieve this, conventional triaxial tests were conducted on saturated phyllite specimens under creep-seepage acoustic emission conditions. The results were systematically analyzed to unveil the inherent characteristics of creep deformation, seepage rate evolution, and damage progression in phyllite when subjected to stress–seepage coupling. Furthermore, a permeability model for representative volume element (RVE) was developed based on meso-mechanics principles, considering the distinctive attributes of low-permeability non-Darcy’s flow in rock. Consequently, a novel relationship between effective damage and permeability was established. We determined that seepage pressure induces three key effects on the creep damage mechanism of phyllite samples: (1) It adds to the existing stress through the superposition of osmotic pressure and axial load, (2) it induces tensile expansion stress because of pore water pressure, and (3) it softens the fracture surfaces to some extent. More importantly, this study validates the relationship between effective damage and permeability through the fitting of creep and damage parameters, which were obtained from the test results, and it reveals a square relationship between subsequent damage and permeability under stress conditions. The findings of this study provide a robust theoretical foundation for comprehending the evolution of damage and permeability characteristics during the creep process of rock under seepage conditions. We obtained essential insights and quantitative analyses for comprehending the damage mechanisms in rock creep under hydraulic coupling, which has significant implications for tunnel engineering and long-term rock stability assessments in soft rock environments.

An Analysis Method of System Coupling and Spatio-Temporal Evolution of County New Urbanization and Logistics Industry

New urbanization in counties and the logistics industry are closely related and are essential in promoting regional economic and social development. There are specific challenges and obstacles to revealing the interaction mechanism and system state measurement between the two. This paper explains the two coupling mechanisms and constructs the evaluation index system. It proposes a new analysis method based on the coupling coordination degree model, the spatio-temporal evolution analysis, and the grey prediction model. The goal is to learn more about and fully realize the coordinated development mechanisms of the two. It then uses the Hebei province of China as an example to empirically analyze its systematic cross-sectional data from 2013 to 2022. Research findings: (1) In Hebei province, the new urbanization in counties and the logistics industry have a systematic coupling relationship. However, the logistics industry’s comprehensive development level is relatively lagging. The two systems have been at a high-level coupling stage for the last decade and maintain a high coupling status. The coupling coordination has shown significant improvement. (2) Although the geographical distribution of the coupling and coordination degree of the new urbanization in counties and logistics industry system has short-term volatility, it is still stable in the long term and presents economic-related spatial characteristics. (3) Over the next five years, the coupling coordination of 11 cities in Hebei province will steadily grow. There will be greater harmonization between the two systems. (4) From the analysis results, the evaluation index system of the coupled system constructed is scientific and reasonable. The analysis method can not only measure the system’s coupling degree, but it can also predict the development trend and analyze the spatial evolution. The technique has novelty and validity, which can be used as a reference for analyzing and making decisions about similar systems.

Study on the Coupled Dynamic Evolution of Social Entrepreneurship and Rural Labor Return in the Context of Rural Revitalization

Based on the panel data of social entrepreneurship and rural labor force return in 31 provinces and municipalities in China from 2016-2021, this paper constructs the evaluation system of entrepreneurial activity from the perspective of rural revitalization, and empirically analyzes it by using entropy weighting method, coupled coordination degree model, and relative development degree model to explore the development level of the two elements. The results show that: at the time level, the return of rural labor force and social entrepreneurship activity in 31 provinces in China from 2016 to 2021 tend to develop in a generally coordinated manner, and the level of coordinated development of the two factors fluctuates and rises; the degree of coupling and coordination of the two factors in general shows a "W"-type cyclical fluctuation characteristic.

Study on thermal‐hydro‐mechanical coupling and stability evolution of loess slope during freeze–thaw process

AbstractDisasters occurring at loess slopes in seasonal frozen regions are closely related to changes in the thermo‐hydro‐mechanical (THM) state in loess by freeze–thaw (FT) action. Current research on FT‐induced soil slope failure focuses on frozen stagnant water effects, while the intrinsic connection between the FT‐induced stagnant water effect and soil strength deterioration remains unclear. In this study, by taking the FT‐induced loess slope failure as an example, field surveys, boreholes, exploratory wells, and 3D topographic mapping were used to reveal the landslide features and stratigraphic information; Furthermore, the temporal and spatial variation of water and heat in loess slope was revealed by on‐site monitoring data; A THM coupled model of frozen soil was established using COMSOL Multiphysics simulation software to reconstruct the frozen stagnant water process of shallow loess slope, as well as the influence of THM field on loess landslide. The results show that the effects of FT in the seasonally frozen region occurred in the shallow layer of the loess slope. The water‐ice phase transition during FT process broke the phase equilibrium of loess. Numerical calculations and field monitoring indicated a continuous migration of water to the freezing front, creating a water‐enriched zone inside the loess. Both the impact of the frozen stagnant water and changes in the stress field led to the degradation of loess structure and reduced the strength properties, thus threatening the stability of the loess slope. The study results can contribute to an in‐depth understanding of the mechanism underlying FT loess landslides in seasonal frozen regions, and provide a scientific basis for the evaluation and prevention of FT landslides.

A radius valley between migrated steam worlds and evaporated rocky cores

AbstractThe radius valley (or gap) in the observed distribution of exoplanet radii, which separates smaller super-Earths from larger sub-Neptunes, is a key feature that theoretical models must explain. Conventionally, it is interpreted as the result of the loss of primordial hydrogen and helium (H/He) envelopes atop rocky cores. However, planet formation models predict that water-rich planets migrate from cold regions outside the snowline towards the star. Assuming water to be in the form of solid ice in their interior, many of these planets would be located in the radius gap contradicting observations. Here we use an advanced coupled formation and evolution model that describes the planets’ growth and evolution starting from solid, moon-sized bodies in the protoplanetary disk to mature Gyr-old planetary systems. Employing new equations of state and interior structure models to treat water as vapour mixed with H/He, we naturally reproduce the valley at the observed location. The model results demonstrate that the observed radius valley can be interpreted as the separation of less massive, rocky super-Earths formed in situ from more massive, ex situ, water-rich sub-Neptunes. Furthermore, the occurrence drop at larger radii, the so-called radius cliff, is matched by planets with water-dominated envelopes. Our statistical approach shows that the synthetic distribution of radii quantitatively agrees with observations for close-in planets, but only if low-mass planets initially containing H/He lose their atmosphere due to photoevaporation, which populates the super-Earth peak with evaporated rocky cores. Therefore, we provide a hybrid theoretical explanation of the radius gap and cliff caused by both planet formation (orbital migration) as well as evolution (atmospheric escape).

Coupled evolution process of lubrication and wear in piston-liner interface of high-pressure common rail pumps

As a pivotal frictional pair of piston pumps, the piston-liner interface is vulnerable to rapid wear in the face of severe environment, triggering a consequent contraction in the piston pump's service longevity. Based on statistical theory, a transient mixed lubrication model has been established in this work, which takes the surface roughness effect, thermal-elastic deformation, as well as the piston micro-movements into account. In conjunction with the wear calculation model, we propose a novel lubrication-wear coupling strategy for the piston-liner interface, enabling a nuanced exploration of the transient interdependency link between lubrication efficiency and wear characteristics. To underscore the robustness of our proposed model, a comparison is drawn with experimental results gleaned from established literature. This investigation not only provides insights into the progression of wear depth and lubrication efficiency throughout a given time frame. but also assesses the impact of varying operational parameters on wear depth Parametric studies reveal that the wear region predominantly occurs at the inlet and outlet positions of the liner. Furthermore, both working pressure and cam rotational speed significantly influence the interface's lubrication characteristics and wear behavior. Consequently, in piston systems operating under high-pressure and high-speed conditions, it is imperative to closely monitor wear patterns and consider the impact of thermal effects.