Evolution Of Coupling Research Articles

Numerical simulation research on multifield coupling evolution mechanism of IN625 laser cladding on nodular cast iron

Numerical simulation research on multifield coupling evolution mechanism of IN625 laser cladding on nodular cast iron

Machine Learning Approach to Calculate Electronic Couplings between Quasi-diabatic Molecular Orbitals: The Case of DNA.

Diabatization of one-electron states in flexible molecular aggregates is a great challenge due to the presence of surface crossings between molecular orbital (MO) levels and the complex interaction between MOs of neighboring molecules. In this work, we present an efficient machine learning approach to calculate electronic couplings between quasi-diabatic MOs without the need of nonadiabatic coupling calculations. Using MOs of rigid molecules as references, the MOs that can be directly regarded to be quasi-diabatic in molecular dynamics are selected out, state tracked, and phase corrected. On the basis of this information, artificial neural networks are trained to characterize the structure-dependent onsite energies of quasi-diabatic MOs and the intermolecular electronic couplings. A representative sequence of DNA is systematically studied as an illustration. Smooth time evolution of electronic couplings in all base pairs is obtained with quasi-diabatic MOs. In particular, our method can calculate electronic couplings between different quasi-diabatic MOs independently, and thus, this possesses unique advantages in many applications.

Fall-to-the-centre as a symmetry breaking transition

The attractive inverse square potential arises in a number of physical problems such as a dipole interacting with a charged wire, the Efimov effect, the Calgero-Sutherland model, near-horizon black hole physics and the optics of Maxwell fisheye lenses. Proper formulation of the inverse-square problem requires specification of a boundary condition (regulator) at the origin representing short-range physics not included in the inverse square potential and this generically breaks the Hamiltonian’s continuous scale invariance in an elementary example of a quantum anomaly. The system’s spectrum qualitatively changes at a critical value of the inverse-square coupling, and we here point out that the transition at this critical potential strength can be regarded as an example of a symmetry breaking transition. In particular, we use point particle effective field theory (PPEFT), as developed by Burgess et al [1], to characterize the renormalization group (RG) evolution of the boundary coupling under rescalings. While many studies choose boundary conditions to ensure the system is unitary, these RG methods allow us to systematically handle the richer case of nonunitary physics describing a source or sink at the origin (such as is appropriate for the charged wire or black hole applications). From this point of view the RG flow changes character at the critical inverse-square coupling, transitioning from a sub-critical regime with evolution between two real, unitary fixed points ( symmetric phase) to a super-critical regime with imaginary, dissipative fixed points ( symmetry broken phase) that represent perfect-sink and perfect-source boundary conditions, around which the flow executes limit-cycle evolution.

Sociohydrology: An Effective Way to Reveal the Coupled Evolution of Human and Water Systems

Sociohydrology: An Effective Way to Reveal the Coupled Evolution of Human and Water Systems

Coupled dynamics and evolution of primordial and recycled heterogeneity in Earth's lower mantle

Abstract. The nature of compositional heterogeneity in Earth's lower mantle remains a long-standing puzzle that can inform about the long-term thermochemical evolution and dynamics of our planet. Here, we use global-scale 2D models of thermochemical mantle convection to investigate the coupled evolution and mixing of (intrinsically dense) recycled and (intrinsically strong) primordial heterogeneity in the mantle. We explore the effects of ancient compositional layering of the mantle, as motivated by magma ocean solidification studies, and of the physical parameters of primordial material. Depending on these physical parameters, our models predict various regimes of mantle evolution and heterogeneity preservation over 4.5 Gyr. Over a wide parameter range, primordial and recycled heterogeneity are predicted to co-exist with each other in the lower mantle of Earth-like planets. Primordial material usually survives as medium- to large-scale blobs (or streaks) in the mid-mantle, around 1000–2000 km depth, and this preservation is largely independent of the initial primordial-material volume. In turn, recycled oceanic crust (ROC) persists as large piles at the base of the mantle and as small streaks everywhere else. In models with an additional dense FeO-rich layer initially present at the base of the mantle, the ancient dense material partially survives at the top of ROC piles, causing the piles to be compositionally stratified. Moreover, the addition of such an ancient FeO-rich basal layer significantly aids the preservation of the viscous domains in the mid-mantle. Finally, we find that primordial blobs are commonly directly underlain by thick ROC piles and aid their longevity and stability. Based on our results, we propose an integrated style of mantle heterogeneity for the Earth involving the preservation of primordial domains along with recycled piles. This style has important implications for early Earth evolution and has the potential to reconcile geophysical and geochemical discrepancies on present-day lower-mantle heterogeneity.

REvolver: Automated running and matching of couplings and masses in QCD

In this article we present REvolver, a C++ library for renormalization group evolution and automatic flavor matching of the QCD coupling and quark masses, as well as precise conversion between various quark mass renormalization schemes. The library systematically accounts for the renormalization group evolution of low-scale short-distance masses which depend linearly on the renormalization scale and sums logarithmic terms of high and low scales that are missed by the common logarithmic renormalization scale evolution. The library can also be accessed through Mathematica and Python interfaces and provides renormalization group evolution for complex renormalization scales as well. Program summaryProgram Title:REvolverCPC Library link to program files:https://doi.org/10.17632/m6cjfmzsxb.1Developer's repository link:https://gitlab.com/REvolver-hep/REvolverCode Ocean capsule:https://codeocean.com/capsule/6150064Licensing provisions: GPLv3 or laterProgramming language:C++, Python, Wolfram LanguageNature of problem: The strong coupling and the quark masses are fundamental parameters of QCD that are scheme and renormalization-scale dependent. The choice of scheme depends on the active number of flavors and the range of scales, and is dictated by the requirements to minimize the size of corrections and to sum large logarithmic corrections to all orders. For the strong coupling and the quark masses at high scales, the MS‾ scheme with logarithmic scale dependence is used. For quark masses at low scales, short-distance mass schemes with linear scale-dependence are used. The REvolver library provides conversions for the strong coupling and the most common quark mass schemes, with renormalization scale evolution implemented such that all types of large logarithmic terms are summed to all orders, accounting for flavor threshold effects and state-or-the-art correction terms. The pole mass, which is not a short-distance mass and contains a sizable renormalon ambiguity, is treated as a derived quantity.Solution method: Renormalization group equations are solved for complex-valued scales to machine precision based on fast-converging iterative algorithms and analytic all-order expressions. Matching relations for the strong coupling at flavor thresholds are computed in a way that gives equal results for upward and downward evolution. Core objects allow to define an arbitrary number of physical scenarios for strong coupling values and quark mass spectra, where options for precision and matching scales can be set freely, and values for quark masses in all common schemes including the pole mass can be extracted. All REvolver routines are implemented entirely in C++ and can be accessed through Mathematica and Python interfaces.

Space-time evolution of Longmenshan fault coupling and moment deficit inverted by multi-source geodetic data

Space-time evolution of Longmenshan fault coupling and moment deficit inverted by multi-source geodetic data

Enhanced integration of flow-based market coupling in short-term adequacy assessment

The resource adequacy of the interconnected Central Western Europe (CWE) electricity system is assessed considering the cross-border exchange capacities defined through the Flow-Based (FB) domains. Integration of FB domains into adequacy assessments poses several challenges since the FB domains depend on factors which are not known over the horizon of adequacy study. Computing hourly FB domains for each generated scenario of adequacy study, firstly, requires adopting assumptions on those unknown parameters (that may not fully match with the reality). Secondly, it noticeably increases the computational complexity of the study. The above challenges can, however, be circumvented by the data-driven alternatives. This paper presents a novel clustering technique for FB domains, which is specifically tailored for adequacy assessments. In contrast to the classical approach employed by the CWE Transmission System Operators (TSOs), which clusters the FB domains based on their overall geometrical resemblance, the proposed technique relies on the maximum and minimum zonal balances allowed by the FB domains, which are decisive factors in the CWE resource adequacy assessments. Indeed, during scarcity moments, the zonal net positions (balances) tend to reach their extreme values to reduce the costs of energy not served. The proposed goal-oriented clustering technique is examined against the classical clustering methodology employed by the CWE TSOs. The conducted simulations demonstrate that the proposed technique considerably (by a factor of over 5.5) improves the accuracy of the CWE adequacy assessments while being scalable with the future evolution of the Flow-based Market Coupling (FBMC). As such, it has direct implications for the adequacy assessment considering the FB domains.

In vivo spectral editing of phosphorylethanolamine.

To demonstrate J-difference editing of phosphorylethanolamine (PE) with chemical shifts at 3.22 (PE3.22 ) and 3.98 (PE3.98 ) ppm, and compare the merits of two editing strategies. Density-matrix simulations of MEGA-PRESS (Mescher-Garwood PRESS) for PE were performed at TEs ranging from 80 to 200 ms in steps of 2 ms, applying 20-ms editing pulses (ON/OFF) at (1) 3.98/7.5 ppm to detect PE3.22 and (2) 3.22/7.5 ppm to detect PE3.98 . Phantom experiments were performed using a PE phantom to validate simulation results. Ten subjects were scanned using a Philips 3T MRI scanner at TEs of 90 ms and 110 ms to edit PE3.22 and PE3.98 . Osprey was used for data processing, modeling, and quantification. Simulations show substantial TE modulation of the intensity and shape of the edited signals due to coupling evolution. Simulated and phantom integrals suggest that TEs of 110 ms and 90 ms were optimal for the edited detection of PE3.22 and PE3.98 , respectively. Phantom results indicated strong agreement with the simulated spectra and integrals. In vivo quantification of the PE3.22 /total creatine and PE3.98 /total creatine concentration ratio yielded values of 0.26 ± 0.04 (between-subject coefficient of variation [CV]: 15.4%) and 0.18 ± 0.04 (CV: 22.8%), respectively, at TE = 90 ms, and 0.24 ± 0.02 (CV: 8.2%) and 0.23 ± 0.04 (CV: 18.0%), respectively, at TE = 110 ms. Simulations and in vivo MEGA-PRESS of PE demonstrate that both PE3.22 and PE3.98 are potential candidates for editing, but PE3.22 at TE = 110 ms yields lower variation across TEs.

The Evolution of Collaboration in Multi-actor R&D Projects: Patterns of Couplings and Innovations

Multi-actor R&D projects are a setting where a network of multiple organizational actors, usually from research and industry, creates a temporary consortium and are funded based upon a proposal to jointly develop new knowledge and innovations. The couplings between the organizations are designed in the proposal, however based on incomplete knowledge. Using a comparative multiple case study of multi-actor projects funded in European Research and Innovation Programs, we investigate why and how these planned couplings, i.e. the collaborations between organizations evolved during the different project phases and what effect this had on the collaborative innovations. We investigated 4 projects with 54 organizations generating 46 innovations, using data from over 740 pages of documentation and over 33 hours of semi-structured interviews with 24 project actors. The study uncovers eight types of reconfigurations of couplings, activated by six disintegrative and two integrative mechanisms. Most of these reconfigurations led to negative consequences for innovations or to innovations created by less partner organizations. The weakening of couplings was much less pronounced within specialized modules (subgroups of closely collaborating partners) within the projects than at the interfaces that were planned to connect the modules. Here, planned strong couplings often degraded into weak couplings or even disappeared over the project lifetime. Based on these findings, we propose a process model of the evolution of couplings in multi-actor R&D projects and implications on collaborative innovations.

Glacier-Induced Alluvial Fan Development on the Northeast Tibetan Plateau Since the Late Pleistocene

The origin of alluvial fans at the drainage basin or the margins of the arid sedimentary basin on the northeastern Tibetan Plateau (NETP) has been a focus of debate among scientific communities. Extensive alluvial fans had developed in the mountain-basin systems of this region during the late Pleistocene. Based on geomorphic/stratigraphic studies and the optically stimulated luminescence (OSL) chronology, we investigated numerous alluvial sequences in the drainage basin of the coupled mountain-basin system on the NETP. Sedimentologic analyses showed that these alluvial sediments mainly comprise crudely meter and decimeter beds of fanglomerate and sandy lenticles, which occasionally contain boulders in the thinner layers. OSL dating results showed that the alluvial sediments were mainly developed during the late MIS 5, MIS 3, and Last Glaciation and Deglaciation (maximum aggradations), while little had occurred during the early Holocene. Comparing our ages and their probability density curves with those of glacial advances from the northeastern/eastern TP, the consistency of both records during different stages since the late Pleistocene suggested that the development of alluvial fans was driven by glacier activities, which yielded abundant outwash, feeding alluvial aggradations. Based on this finding, together with results of previous studies, we argued that the dynamics of alluvial geomorphic processes had a paleoclimatic origin rather than surface uplifts. Further studies indicated that the precipitation of glaciations originated from the ISM northward intrusion during the late MIS 5, MIS 3, and Holocene; however, it was mainly influenced by the westerlies during the Last Glaciation and Deglaciation. Therefore, the development of alluvial fans on the NETP represents coupling signals of the ISM and the westerlies on the interglacial–glacial cycle timescales. The coupling evolution of glacier activities and alluvial aggradations in the drainage basins of mountain-basin systems on the NETP provides a model for assessing the linkages between regional geomorphic processes and atmospheric circulations on hemispheric scales.

Modelling the coupling evolution of the water environment and social economic system using PSO-SVM in the Yangtze River Economic Belt, China

Being a crucial focal point of China's regional development, green development is a novel concept for the coordinated development of the environment and social economy. Therefore, elucidation of the relationship between the aforementioned factors is scientifically necessary to achieve regional green sustainability. Based on the theory of the gray water footprint and physical and statistical models, this study aims to analyze, evaluate, and predict the spatiotemporal dynamics of the coupling evolution between the water environment and social economy in the Yangtze River Economic Belt to provide a scientific reference for exploring basic laws of coordinated development, identifying influencing factors, and formulating management strategies. The results showed that: (1) from 2003 to 2017, the carrying capacity coefficients of the gray water footprint (i.e., the KCOD, KNH3-N, and KTP, except for KTN) decreased over time, as shown by a decreasing trend in the degree of the coupling coordination, which was observed from the east to the west; (2) the coupling coordination degree showed a decreasing trend from the east to the west at the spatial level and an increasing trend from 2003 to 2017 at the temporal level; and (3) the optimal scenario was green development (Plan IV) and the overall coordination degree improved. In addition, corresponding policy recommendations were proposed. The research results are scientifically significant and present a theoretical reference for the coordinated and sustainable development of the regional ecological environment and social economy.

Nonthermal Transport of Energy Driven by Photoexcited Carriers in Switchable Solid States of GeTe

Phase change alloys have seen widespread use from rewritable optical discs to the present day interest in their use in emerging neuromorphic computing architectures. In spite of this enormous commercial interest, the physics of carriers in these materials is still not fully understood. Here, we describe the time and space dependence of the coupling between photoexcited carriers and the lattice in both the amorphous and crystalline states of one phase change material, GeTe. We study this using a time-resolved optical technique called picosecond acoustic method to investigate the \textit{in situ} thermally assisted amorphous to crystalline phase transformation in GeTe. Our work reveals a clear evolution of the electron-phonon coupling during the phase transformation as the spectra of photoexcited acoustic phonons in the amorphous ($a$-GeTe) and crystalline ($\alpha$-GeTe) phases are different. In particular and surprisingly, our analysis of the photoinduced acoustic pulse duration in crystalline GeTe suggests that a part of the energy deposited during the photoexcitation process takes place over a distance that clearly exceeds that defined by the pump light skin depth. In the opposite, the lattice photoexcitation process remains localized within that skin depth in the amorphous state. We then demonstrate that this is due to supersonic diffusion of photoexcited electron-hole plasma in the crystalline state. Consequently these findings prove the existence of a non-thermal transport of energy which is much faster than lattice heat diffusion.

Real‐Time Spectral Evolution of Interchain Coupling and Assembling during Solvent Vapor Annealing of Dispersed Conjugated Polymers

AbstractSolvent vapor annealing (SVA) for polymer treatment is widely used for manufacturing organic photovoltaic devices, but the process is poorly understood on the microscopic scale. In this study, an optical monitoring system is designed and used to perform real‐time fluorescence analysis of dispersed poly(3‐hexylthiophene) (P3HT) and para‐phenylene ethynylene (PPE) films during SVA. The initial swelling of aggregates occurs within seconds. Chain rearrangements then occur and an equilibrium state is reached within minutes. Surface morphologies for both P3HT and PPE polymers are examined using atomic force microscopy (AFM) before and after the SVA process. Although similar transformations from random globules to micrometer‐scale nanowires are observed for both polymers, P3HT forms nanowires more easily and quickly than PPE does. The higher solubility of P3HT in chloroform results in superior long‐range order; by contrast, PPE chains align into nanowires only with sufficient free space. Real‐time spectroscopic monitoring of structures and morphological characterization of such structures through AFM during SVA can improve the understanding of how polymer chains rearrange into ordered structures.

Baryogenesis, magnetogenesis and the strength of anomalous interactions

The production of the hypermagnetic gyrotropy is investigated under the assumption that the gauge coupling smoothly evolves during a quasi-de Sitter phase and then flattens out in the radiation epoch by always remaining perturbative. In the plane defined by the strength of the anomalous interactions and by the rate of evolution of the gauge coupling the actual weight of the pseudoscalar interactions turns out to be always rather modest if major deviations from the homogeneity are to be avoided during the inflationary phase. Even if the gauge power spectra are related by duality only in the absence of anomalous contributions, an approximate duality symmetry constrains the late-time form of the hypermagnetic power spectra. Since the hypermagnetic gyrotropy associated with the modes reentering prior to the phase transition must be released into fermions later on, the portions of the parameter space where the obtained baryon asymmetry is close to the observed value are the most relevant for the present ends. For the same range of parameters the magnetic power spectra associated with the modes reentering after symmetry breaking may even be of the order of a few hundredths of a nG over typical length scales comparable with the Mpc prior to the collapse of the protogalaxy.

Multi-hazard disaster scenario method and emergency management for urban resilience by integrating experiment–simulation–field data

Due to the frequent occurrence of multi-hazard disasters worldwide in recent years, effective multi-hazard scenario analysis is imperative for disaster rescue and emergency management. The response procedure for different single hazards were investigated and formulated before. However, the investigations of disaster scenario rarely systematically address the entire development and response process of multi-hazards, including the coupling mechanisms, evolution dynamics, scenario assessment and emergency response. To this end, this paper presents our methodology of multi-hazard disaster scenario that integrates experiment–simulation–field data, focusing on three dimensions consisting of multi-hazard coupling, structures and systems, and emergency management. The newly proposed scenario method mainly comprises three aspects: experiments and simulations, multi-hazard field investigation, scenario analysis and response. Specifically, in order to study the large-scale, high-intensity and multi-hazard coupling effects, we carried out reduced-scale experiments and field measurement experiments to develop experimental similarity theory and prototype simulations of multi-hazards. In addition, a variety of field rescue and survey equipment, such as robots, Unmanned Aerial Vehicle (UAV), and Virtual Reality/Augmented Reality (VR/AR) technologies were utilized to acquire real-time data of multi-hazard field. Furthermore, we also examine the mechanism and framework of multi-hazard scenarios to formulate the detailed procedures of management and response. They are incorporated with the experiments, simulations, field data and models to construct a new scenario platform. The proposed scenario method was applied in a case study of the coupled wind and snow multi-hazard to verify its effectiveness. The new method contributes to the disaster relief, decision-making and emergency management for multi-hazard disaster to improve the urban resilience.

Spatiotemporal Differentiation of Coupling and Coordination Relationship of Tourism–Urbanization–Ecological Environment System in China’s Major Tourist Cities

Determining the coupling development mode and evolution process of the tourism–urbanization–ecological environment system is of great significance in promoting high-quality and sustainable development of tourism and the urban economy. In this study, an evaluation index system of the tourism–urbanization–ecological environment system was established, and the spatiotemporal differentiation of the coupling and coordination relationship of the tourism–urbanization–ecological environment system was analyzed for 35 major tourist cities in China from 2009 to 2018. The results show that the comprehensive development indices of the tourism industry subsystem and urbanization subsystem of China’s major tourist cities have steadily increased. The comprehensive development indices of large-sized and medium-sized cities in the east are relatively high. From 2009 to 2018, the coordination degree and coupling degree of the tourism–urbanization–ecological environment’ system of 35 tourist cities showed an upward trend. The growth rate of the coupling coordination degree lags behind the growth rate of the coupling degree, and the overall system coordination level is still low. There are significant differences in the coupling degree and coupling coordination degree among the eastern, central, and western cities. This study offers both theoretical and practical implications for further equalizing the development level between the cities, as well as improving the overall coordination between the tourism industry, urbanization, and the ecological environment in China.

Understanding the Characteristics and Realization Path of Urban Land Use Transition in the Bohai Economic Rim: An Analytical Framework of “Dominant-Recessive” Morphology Coupling

Taking the Bohai Economic Rim as the research area and 44 prefecture-level cities as research objects, on the basis of deepening the connotation of urban land use morphology, we constructed a multi-dimensional indicator system for urban land use transition based on the dominant and recessive morphologies of land use. The patterns of change and transition type are described by single-morphology and comprehensive morphology indices, respectively, while a decoupling elastic coefficient model was used to analyze the coupling relationship and evolution process between the dominant and recessive morphologies of urban land use. The results showed the following: (1) From 2000 to 2020, the single-morphology and comprehensive morphology indices of urban land use in the Bohai Economic Rim both improved, to a certain extent. Overall, the transition types of dominant and recessive morphologies of urban land use showed a development trend, in which the degree of recessive morphology transition was higher than the degree of dominant morphology transition, and the spatial difference of its distribution pattern was obvious. (2) From 2000 to 2020, the type of coupling relationship between the dominant and recessive morphologies of urban land use in the Bohai Economic Rim experienced an evolution, from a single-morphology recession decoupling to a single-morphology leading positive hook. The whole region was in the benign development stage of close coupling, where the degree of transition showed the spatial characteristics of Beijing–Tianjin–Hebei > Liaodong Peninsula > Shandong Peninsula. (3) Differences in the economic levels and urbanization processes of different cities led to different paths, speeds, and degrees of urban land use transition, showing stable, volatile, and non-transition paths. The direct influence of different influencing factors, as well as their potential effects, drive the dominant and recessive morphologies of urban land use to grow, in terms of coupling and synergy, promoting the realization of urban land use transition.

Broadband chiral silicon photonic circuits based on fork-type inversely tapered nanowire waveguides.

Optical spin or circular polarization provides a new degree of freedom to control light-matter interaction in the fundamentals and applications of light. To broaden the bandwidth of chiral (spin-controlled) coupling in photonic integrated circuits, we propose fork-type inversely tapered nanowire waveguides to compensate for the out-of-step phase evolution of adiabatic coupling between ${{\rm TE}_0}$ and ${{\rm TM}_0}$ (${{\rm TE}_1}$) modes excited from the $x$- and $y$-polarization components of spin polarized light in free space, respectively. We design and simulate two kinds of devices based on air and ${{\rm Si}_3}{{\rm N}_4}$ up-claddings to show the feasibility of broadening the bandwidth of chiral silicon photonic circuits by using fork-type inverse tapers. Numerical results show that the bandwidth can approach 70 nm under high directionality of above 0.90. This broadband chiral coupling via the new phase synchronizing technique with fork-type inverse tapers may pave the way to develop on-chip spin photonics or polarization-based photonic integrated devices.

The low-energy effective theory of axions and ALPs

Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.