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We analyze the displacements of the particles of a glass-forming molecular liquid perpendicular to a confining solid surface using extensive molecular dynamics simulations with atomistic models. In the vicinity of an attractive surface, the liquid molecules are trapped. Transient localization of liquid molecules near the surface introduces a relaxation process related to the escape of molecules from the surface into the dynamics of the interfacial liquid layer. To describe this process, we analyze several dynamical observables of the confined liquid. The self-intermediate scattering function and the mean-squared displacement of the particles located in the interfacial layer are dominated by the process of escaping from the surface. This relaxation process is also associated with a strong heterogeneity in the mobility of the interfacial particles. The studied model liquid is hydrogenated methyl methacrylate. For the confining wall, we consider different models, namely a periodic single layer of graphene and a frozen amorphous configuration of the bulk liquid (frozen wall). Near graphene, where the liquid molecules form a layered structure and adopt parallel-to-surface orientation, a clear separation between small-scale movements of the molecules near the surface and the process of escaping from the surface is observed. This is reflected in the three-step relaxation of the interfacial layer. However, near the frozen wall, where the liquid molecules do not have a preferential alignment, a clear three-step relaxation is not seen, even though the dynamical quantities are controlled by the process of escaping from the surface. [ABSTRACT FROM AUTHOR]

Two-dimensional electronic spectroscopy (2D-ES) has become an important technique for studying energy transfer, electronic coupling, and electronic–vibrational coherence in the past ten years. However, since 2D-ES is not interface specific, the electronic information at surfaces and interfaces could not be demonstrated clearly. Two-dimensional electronic sum-frequency generation (2D-ESFG) is an emerging spectroscopic technique that explores the correlations between different interfacial electronic transitions and is the extension of 2D-ES to surface and interfacial specificity. In this work, we present the detailed development and implementation of phase-cycling 2D-ESFG spectroscopy using an acousto-optic pulse shaper in a pump–probe geometry. With the pulse pair generated by a pulse shaper rather than optical devices based on birefringence or interference, this 2D-ESFG setup enables rapid scanning, phase cycling, and the separation of rephasing and nonrephasing signals. In addition, by collecting data in a rotating frame, we greatly improve experimental efficiency. We demonstrate the method for azo-derivative molecules at the air/water interface. This method could be readily extended to different interfaces and surfaces. The unique phase-cycling 2D-ESFG technique enables one to quantify the energy transfer, charge transfer, electronic coupling, and many other electronic properties and dynamics at surfaces and interfaces with precision and relative ease of use. Our goal in this article is to present the fine details of the fourth-order nonlinear optical technique in a manner that is comprehensive, succinct, and approachable such that other researchers can implement, improve, and adapt it to probe unique and innovative problems to advance the field. [ABSTRACT FROM AUTHOR]

Strong coupling between the molecular system and photon inside the cavity generates polaritons, which can alter reaction rates by orders of magnitude. In this work, we benchmark the surface hopping method to simulate non-adiabatic dynamics in a cavity. The comparison is made against a numerically exact method (the hierarchical equations of motion) for a model system investigating excitonic energy transfer for a broad range of parameters. Surface hopping captures the effects of the radiation mode well, both at resonance and off-resonance. We have further investigated parameters that can increase or decrease the rate of population transfer, and we find that surface hopping in general can capture both effects well. Finally, we show that the dipole self-energy term within our parameter regime does not significantly affect the system's dynamics. [ABSTRACT FROM AUTHOR]

In this article, significant contributions of non-adiabaticity for the rovibrational bound states up to 25 000 cm−1 and total angular momentum J = 0–20 of H 3 + are investigated. A coupled-perturbed full configuration interaction (CP-FCI) treatment is applied to calculate all couplings between electronic states caused by the nuclear motion. These derivative couplings were evaluated up to the second order by means of a perturbation treatment and include all nuclear Cartesian first and second derivatives of the electronic wavefunctions. In particular, the coupling of special derivatives with respect to r and R in the Jacobi coordinate representation is more significant than thought. The perturbation approach is especially optimal for the treatment of weak non-adiabaticity in case of rovibrational energies in H 3 + and had not been available before for H 3 + or other triatomics. Using exclusively Gaussian basis functions for CP-FCI appears to be sufficient, because explicit correlated wavefunctions are already used for all other potential energy contributions. Our work is an extension of earlier non-adiabatic investigations based on first derivative couplings of electronic states that led to the concept of geometry-dependent effective nuclear masses and which needs only a single potential energy surface for the dynamics. The implementation allows us to include all non-adiabatic effects up to the order of O ( μ − 2 ) , μ being the reduced nuclear mass. Our treatment works for any isotopologue and for the whole potential energy curve or surface. By this treatment, a further reduction in deviations to experimental data for most rovibrational levels to less than 0.1 cm−1 is possible. For the related transition frequencies, 1366 of 1720 known rovibrational transitions in H 3 + have deviations less than 0.1 cm−1 without using any empirically adjustable parameters or optimizing the nuclear mass for a specific transition. For many questionable assignments (deviations > 0.3 cm−1) of observed transitions in H 3 + , a new labeling is proposed. [ABSTRACT FROM AUTHOR]

Metals exhibit nonequilibrium electron and lattice subsystems at transient times following femtosecond laser excitation. In the past four decades, various optical spectroscopy and time-resolved diffraction methods have been used to study electron–phonon coupling and the effects of underlying dynamical processes. Here, we take advantage of the surface specificity of reflection ultrafast electron diffraction (UED) to examine the structural dynamics of photoexcited metal surfaces, which are apparently slower in recovery than predicted by thermal diffusion from the profile of absorbed energy. Fast diffusion of hot electrons is found to critically reduce surface excitation and affect the temporal dependence of the increased atomic motions on not only the ultrashort but also sub-nanosecond times. Whereas the two-temperature model with the accepted physical constants of platinum can reproduce the observed surface lattice dynamics, gold is found to exhibit appreciably larger-than-expected dynamic vibrational amplitudes of surface atoms while keeping the commonly used electron–phonon coupling constant. Such surface behavioral difference at transient times can be understood in the context of the different strengths of binding to surface atoms for the two metals. In addition, with the quantitative agreements between diffraction and theoretical results, we provide convincing evidence that surface structural dynamics can be reliably obtained by reflection UED even in the presence of laser-induced transient electric fields. [ABSTRACT FROM AUTHOR]

The comprehension of nonadiabatic dynamics in polyatomic systems relies heavily on the simultaneous advancements in theoretical and experimental domains. The gas-phase ultrafast electron diffraction (UED) technique has attracted significant attention as a unique tool for monitoring photochemical and photophysical processes at the all-atomic level with high temporal and spatial resolutions. In this work, we simulate the UED spectra of cyclobutanone using the trajectory surface hopping method at the extended multi-state complete active space second order perturbation theory (XMS-CASPT2) level and thereby predict the results of the upcoming UED experiments in the Stanford Linear Accelerator Laboratory. The simulated results demonstrate that a few pathways, including the C2 and C3 dissociation channels, as well as the ring opening channel, play important roles in the nonadiabatic reactions of cyclobutanone. We demonstrate that the simulated UED signal can be directly interpreted in terms of atomic motions, which provides a unique way of monitoring the evolution of the molecular structure in real time. Our work not only provides numerical data that help to determine the accuracy of the well-known surface hopping dynamics at the high XMS-CASPT2 electronic-structure level but also facilitates the understanding of the microscopic mechanisms of the photoinduced reactions in cyclobutanone. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the Floquet mean-field dynamics and Floquet surface hopping approaches to study the nonadiabatic dynamics in periodically driven solid systems. We demonstrate that these two approaches can be formulated in both real and reciprocal spaces. Using the two approaches, we are able to simulate the interaction between electronic carriers and phonons under periodic drivings, such as strong light–matter interactions. Employing the Holstein and Peierls models, we show that strong light–matter interactions can effectively modulate the dynamics of electronic population and mobility. Notably, our study demonstrates the feasibility and effectiveness of modeling low-momentum carriers' interactions with phonons using a truncated reciprocal space basis, an approach impractical in real space frameworks. Moreover, we reveal that even with a significant truncation, carrier populations derived from surface hopping maintain greater accuracy compared to those obtained via mean-field dynamics. These results underscore the potential of our proposed methods in advancing the understanding of carrier–phonon interactions in various periodically driven materials. [ABSTRACT FROM AUTHOR]

The impacting phenomenon of nanodroplets has received much attention due to their importance in various industrial applications. The oblique impingement of single droplets is well understood; however, the effect of oblique angle on impacting the dynamics of multiple droplets at the nanoscale is very limited. To address this gap, we perform molecular dynamics (MD) simulations to study the impacting dynamics of binary nanodroplets with various oblique angles (αob) and Weber numbers (We). Using MD simulations, we directly capture the detailed morphological evolution of the impacting binary droplets with various given conditions. Compared to the oblique impingement of a single droplet, the evolution of impacting binary droplets involves two novel dynamic characteristics: the asymmetric dynamics with droplet preferential spreading in the y direction and the rotating of the coalescing droplet. The mechanisms underlying are well studied. The asymmetric dynamics is a result of the velocity gradient of the outer edge of the spreading droplet, and the rotating effect is due to the change in angular momentum induced by surface force. The analysis and study of these phenomena have never been mentioned in previous studies of single droplet. Finally, we investigate the effect of αob and We on normalized moving distance (L/Dsin) and contact time (tc). This work paves the way for offering a comprehensive understanding of the oblique impingement of binary nanodroplets. [ABSTRACT FROM AUTHOR]

This research examines the nonadiabatic dynamics of cyclobutanone after excitation into the n → 3s Rydberg S2 state. It stems from our contribution to the Special Topic of the Journal of Chemical Physics to test the predictive capability of computational chemistry against unseen experimental data. Decoherence-corrected fewest-switches surface hopping was used to simulate nonadiabatic dynamics with full and approximated nonadiabatic couplings. Several simulation sets were computed with different electronic structure methods, including a multiconfigurational wavefunction [multiconfigurational self-consistent field (MCSCF)] specially built to describe dissociative channels, multireference semiempirical approach, time-dependent density functional theory, algebraic diagrammatic construction, and coupled cluster. MCSCF dynamics predicts a slow deactivation of the S2 state (10 ps), followed by an ultrafast population transfer from S1 to S0 (<100 fs). CO elimination (C3 channel) dominates over C2H4 formation (C2 channel). These findings radically differ from the other methods, which predicted S2 lifetimes 10–250 times shorter and C2 channel predominance. These results suggest that routine electronic structure methods may hold low predictive power for the outcome of nonadiabatic dynamics. [ABSTRACT FROM AUTHOR]

Methyl nitrite has two stable conformational isomers resulting from rotation about the primary C–O–N–O dihedral angle: cis-CH3ONO and trans-CH3ONO, with cis being more stable by ∼5 kJ/mol. The barrier to rotational interconversion (∼45 kJ/mol) is too large for isomerization to occur under ambient conditions. This paper presents evidence of a change in conformer abundance when dilute CH3ONO is deposited onto a cold substrate; the relative population of the freshly deposited cis conformer is seen to increase compared to its gas-phase abundance, measured by in situ infrared spectroscopy. We observe abundance changes depending on the identity of the bath gas (N2, Ar, and Xe) and deposition angle. The observations indicate that the surface properties of the growing matrix influence conformer abundance—contrary to the widely held assumption that conformer abundance in matrices reflects gas-phase abundance. We posit that differences in the angle-dependent host-gas deposition dynamics affect the growing surfaces, causing changes in conformer abundances. Quantum chemistry calculations of the binding energies between CH3ONO and a single bath-gas component reveal that significant energetic stabilization is not observed in 1:1 complexes of N2:CH3ONO, Ar:CH3ONO, or Xe:CH3ONO. From our results, we conclude that the growing surface plays a significant role in trapping cis-CH3ONO more effectively than trans-CH3ONO, likely because cis-CH3ONO is more compact. Taken together, the observations highlight the necessity for careful characterization of conformers in matrix-isolated systems, emphasizing a need for further study into the deposition dynamics and surface structure of chemically inert matrices. [ABSTRACT FROM AUTHOR]

Dissociative adsorption onto a surface introduces dynamic correlations between neighboring sites not found in non-dissociative absorption. We study surface coverage dynamics where reversible dissociative adsorption of dimers occurs on a finite linear lattice. We derive analytic expressions for the equilibrium surface coverage as a function of the number of reactive sites, N, and the ratio of the adsorption and desorption rates. Using these results, we characterize the finite size effect on the equilibrium surface coverage. For comparable N's, the finite size effect is significantly larger when N is even than when N is odd. Moreover, as N increases, the size effect decays more slowly in the even case than in the odd case. The finite-size effect becomes significant when adsorption and desorption rates are considerably different. These finite-size effects are related to the number of accessible configurations in a finite system where the odd-even dependence arises from the limited number of accessible configurations in the even case. We confirm our analytical results with kinetic Monte Carlo simulations. We also analyze the surface-diffusion case where adsorbed atoms can hop into neighboring sites. As expected, the odd-even dependence disappears because more configurations are accessible in the even case due to surface diffusion. [ABSTRACT FROM AUTHOR]

Accurate extraction of Seasonally Inundated Area (SIA) is pivotal for precise delineation of Flood Inundation Area (FIA). Current methods predominantly rely on Water Inundation Frequency (WIF) to extract SIA, which, due to the lack of analysis of dynamic surface water changes, often yields less accurate and robust results. This significantly hampers the rapid and precise mapping of FIA. In the study, based on the Harmonic Models constructed from Long Time-series Surface Water (LTSW) dynamics, an SIA extraction approach (SHM) was introduced to enhance their accuracy and robustness, thereby improving flood mapping. The experiments were conducted in Poyang Lake, a region characterized by active hydrological phenomena. Sentinel-1/2 remote sensing data were utilized to extract LTSW. Harmonic analysis was applied to the LTSW dataset, using the amplitude terms in the harmonic model to characterise the frequency of variation between land and water for the surface units, thus extracting the SIAs. The results reveal that the harmonic model parameters are capable of portraying SIA. In comparison to the commonly used WIF thresholding method for SIA extraction, the SHM approach demonstrates superior accuracy and robustness. Leveraging the SIA extracted through SHM, a higher level of accuracy in FIA extraction is achieved. Overall, the SHM offers notable advantages, including high accuracy, automation, and robustness. It offers reliable reference water extents for flood mapping, especially in areas with active and complex hydrological dynamics. SHM can play a crucial role in emergency response to flood disasters, providing essential technical support for natural disaster management and related departments. [ABSTRACT FROM AUTHOR]

The integration of data from multiple satellite altimetry missions, each offering unique observational characteristics, has enabled us to discern both short-term variability and long-term climate trends affecting Greenland's peripheral glaciers and the Greenland Ice Sheet (GrIS). Our methodology, adapted and informed by lessons learned from our similar efforts in Antarctica, ensures the consistency and reliability of the derived elevation change dataset. The data covers the years 1992–2023 and is made publicly available as part of the NASA's Making Earth System Data Records for Use in Research Environments (MEaSUREs) Inter-Mission Time Series of Land Ice Velocity and Elevation (ITS_LIVE) project. Our analysis of the dataset reveals significant patterns of mass loss across the GrIS. We find that the ice sheet and peripheral glaciers have experienced an average mass loss of -173 ± 19 Gt a-1 and -23 ± 5 Gt a-1 respectively over the 1992–2022 time period (given temporal availability of selected firn models), with notable variations over time. Specifically, the early years of the record exhibit a positive mass balance, likely due to anomalously positive surface mass balance. However, this trend shifts in subsequent years, with a pronounced increase in mass loss rates, highlighting the accelerating impact of a changing climate on ice sheet dynamics and surface mass balance. Moreover, our analysis underscores the importance of considering peripheral glaciers in addition to the continental ice sheet when assessing overall mass trends. By incorporating data from peripheral glaciers, we provide a more comprehensive understanding of Greenland's total contributions to global sea level rise. Our findings reveal not only the magnitude of mass loss but also its evolution over time, emphasizing the need for continued monitoring and research to better understand the impacts of climate change on Earth's cryosphere. [ABSTRACT FROM AUTHOR]

Africa has the most dynamic demographic development worldwide. Current projections predict a population of > 3 billion people by the end of the century. Sub-Saharan Africa alone will likely see a 40% increase in population between 2020 and 2050. Although it is well known that large parts of Africa are in a constant state of water stress, its surface water resources remain understudied. This study analyses long-term trends of surface water in Africa. It identifies causal impacts on major lakes and reservoirs for the timeframe 2003–2020, as well as dynamic and causal similarities between the various lakes. For this, a set of daily time series based on Earth observation is employed. Global WaterPack data is used for a daily uninterrupted time series of the continent’s surface water area. Additionally, an array of relevant independent variables, namely precipitation, total evapotranspiration, groundwater, soil moisture, and gross primary productivity (GPP) in different land use areas is analysed. For causal identification, the Peter and Clark Momentary Conditional Independence algorithm is used. Findings show that > 42% of African countries and > 34% of African ecoregions experience shrinking surface water area. Over 80% of investigated surface water bodies are driven by the surface water in their upstream subbasins and GPP in agriculturally used areas. About 85% of investigated lakes are significantly driven by agricultural usage, often in the form of water abstraction, as referenced regional studies confirm. Our analysis demonstrates the feasibility of conducting causal analyses of surface water dynamics using Earth observation data. Dynamically similar lakes are often impacted by the same drivers, forming regional lake clusters. Considering the causes identified may greatly help adapt strategies for sustainable development. A causality analysis to identify drivers of surface water dynamics has, to our knowledge, never been performed before on this scale and at such high temporal resolution. [ABSTRACT FROM AUTHOR]

A lack of high‐density rootzone soil moisture (θRZ) observations limits the estimation of continental‐scale, space‐time contiguous θRZ dynamics. We derive a proxy of daily θRZ dynamics — active rootzone degree of saturation (SRZ) — by recursive low‐pass (LP) filtering of surface soil moisture (θS) within a terrestrial water‐energy coupling (WEC) framework. We estimate the LP filter parameters and WEC thresholds for the piecewise‐linear coupling between SRZ and evaporative fraction (EF) at remote sensing and field scale over the Contiguous U.S. We use θS from the Soil Moisture Active‐Passive (SMAP) satellite and 218 in‐situ stations, with EF from the Moderate Resolution Imaging Spectroradiometer. The estimated SRZ compares well against SMAP Level‐4 estimates and in‐situ θRZ, at the corresponding scale. The instantaneous hydrologic state (SRZ) vis‐à‐vis the WEC thresholds is proposed as a rootzone soil moisture stress index (SMSRZ) for near‐real‐time operational agricultural drought monitoring and agrees well with established drought metrics. Plain Language Summary: Rootzone soil moisture plays a vital role in agricultural, hydrological, and ecosystem processes. The available spaceborne satellites for monitoring soil moisture can only capture variability in a shallow soil layer at the surface, typically limited to the top 5 cm. Hence, spatiotemporally continuous estimation of rootzone soil moisture dynamics typically relies on soil moisture estimates from land‐surface models, which are subject to errors in the surface meteorological forcing data, process formulations, and model parameters. Some studies suggest that the rootzone soil moisture dynamics can be estimated by filtering the high‐frequency variability in the surface soil moisture. However, such "filters" require observed rootzone data (often unavailable at high spatial density) for calibration. This study uses the relationship between surface soil moisture and evaporative fraction derived using spaceborne observations from the Soil Moisture Active Passive mission and the Moderate Resolution Imaging Spectroradiometer to estimate rootzone soil moisture dynamics for the Contiguous U.S. at 9 km grid resolution. We further demonstrate that this approach can be extended into a near‐real‐time agricultural drought monitor to assess drought impacts on vegetation using surface soil moisture observations. Key Points: Terrestrial water‐energy coupling is used to parameterize low‐pass filter to estimate rootzone dynamics from surface soil moistureRootzone degree of saturation and water‐energy coupling thresholds are estimated using evaporative fraction and surface soil moistureSMAP‐based rootzone degree of saturation can used for operational, near‐real‐time agricultural drought monitoring over Contiguous U.S [ABSTRACT FROM AUTHOR]

Due to high sensitivity of fluid particles to temperature changes, the thermophysical characteristics of fluids are known to exhibit significant variations when exposed to temperature rise, which can impact the overall efficiency of conveying fluid substances in manufacturing processes across different surfaces and media. Industrial and mechanical processes such as aerodynamic extrusion in plastic sheets, fiber technology and biological dynamics as transpiration and muscle cramps exhibit different surface dynamics. The Reiner–Philippoff (RP) fluid model exemplifies shear-thinning, shear-thickening and Newtonian behavior. This study investigates the flow of a RP fluid over a stretching and shrinking surface with nonlinear thermal convection and variable thermophysical properties. The mathematical models describing the dynamical system are transformed through a similar group of transformations. Flow variables such as the fluid's velocity, temperature and solute concentration were numerically obtained through the spectral local linearization technique (SLLM). Subject to the validation and accuracy of the numerical results, the effects of pertinent parameters on the flow were investigated. The findings in this study reveal that the effects of the flow variables on stretching and shrinking sheets are not diametrically opposite. Moreover, the radiation negatively impacts the flow variables over a stretching sheet compared to the positive effect experienced at some point in flow over a shrinking sheet. [ABSTRACT FROM AUTHOR]

Using angle-resolved X-ray photoelectron spectroscopy, sum-frequency generation vibrational spectroscopy, contact angle measurements, and molecular dynamics simulations, we verify that the glass transition temperature (Tg) of polymer glass is lower near the free surface. However, the experimental Tg-gradients showed a linear variation with depth (z) from the free surface, while the simulated equilibrium Tg-gradients exhibited a double exponential z-dependence. In typical simulations, Tg is determined based on the relaxation time of the system reaching a prescribed threshold value at equilibrium. Conversely, the experiments determined Tg by observing the unfreezing of molecular mobility during heating from a kinetically arrested, nonequilibrium glassy state. To investigate the impact of nonequilibrium effects on the Tg-gradient, we reduced the thermal annealing time in simulations, allowing the system to fall out of equilibrium. We observe a decrease in the relaxation time and the emergence of a modified z-dependence consistent with a linear Tg-gradient near the free surface. We further validate the impact of nonequilibrium effects by studying the dependence of the Tg on the heating/cooling rate for polymer films of varying thickness (h). Our experimental results reveal significant variations in the Tg-heating/cooling rate dependence with h below the bulk Tg, which are also observed in simulation when the simulated system is not equilibrated. We explain our findings by the reduction in mass density within the inner region of the system under nonequilibrium conditions, as observed in simulation, and recent research indicating a decrease in the local Tg of a polymer when placed next to a softer material. [ABSTRACT FROM AUTHOR]

The dynamics of Sea Surface Temperature (SST) are crucial for maintaining the balance of marine ecosystems. While existing artificial intelligence methods offer powerful tools for SST prediction, they struggle with data sparsity issues. To enhance SST prediction accuracy under sparse data conditions, this study proposes an innovative prediction model: TL-iTransformer. This model is based on the iTransformer architecture and incorporates transfer learning techniques specifically tailored for SST prediction. We begin by extracting SST features from data-rich sea areas (source sea areas) using a transfer learning strategy, integrating these features into the iTransformer model for pre-training. This process imparts the model with a priori knowledge and basic prediction capabilities, enabling it to adapt to data-sparse sea areas (target sea areas). The model is then fine-tuned using domain adaptive techniques to accurately capture the data characteristics and distribution patterns of the target sea area. We conducted a series of experiments using a real SST dataset from the sea area of British Columbia, Canada. The results demonstrate that TL-iTransformer maintains the Mean Absolute Error (MAE) and Mean Squared Error (MSE) within 0.144 and 0.356, respectively, under data sparsity conditions. Additionally, it outperforms four mainstream time-series prediction baseline models as the prediction time span increases. The proposed model can effectively address the issue of SST prediction in situations with sparse data. [ABSTRACT FROM AUTHOR]

β-amyloid (Aβ) peptides form self-organizing fibrils in Alzheimer's disease. The biologically active, toxic Aβ25–35 fragment of the full-length Aβ-peptide forms a stable, oriented filament network on the mica surface with an epitaxial mechanism at the timescale of seconds. While many of the structural and dynamic features of the oriented Aβ25–35 fibrils have been investigated before, the β-strand arrangement of the fibrils and their exact orientation with respect to the mica lattice remained unknown. By using high-resolution atomic force microscopy, here, we show that the Aβ25–35 fibrils are oriented along the long diagonal of the oxygen hexagon of mica. To test the structure and stability of the oriented fibrils further, we carried out molecular dynamics simulations on model β-sheets. The models included the mica surface and a single fibril motif built from β-strands. We show that a sheet with parallel β-strands binds to the mica surface with its positively charged groups, but the C-terminals of the strands orient upward. In contrast, the model with antiparallel strands preserves its parallel orientation with the surface in the molecular dynamics simulation, suggesting that this model describes the first β-sheet layer of the mica-bound Aβ25–35 fibrils well. These results pave the way toward nanotechnological construction and applications for the designed amyloid peptides. [ABSTRACT FROM AUTHOR]

Interactions between ocean surface currents, winds and waves at the atmosphere-ocean interface are key controls of lateral and vertical exchanges of water, heat, carbon, gases and nutrients in the global Earth System. The SeaSTAR satellite mission concept proposes to better quantify and understand these important dynamic processes by measuring two-dimensional fields of total surface current and wind vectors with unparalleled spatial and temporal resolution (1 × 1 km2 or finer, 1 day) and unmatched precision over one continuous wide swath (100 km or more). This paper presents a comprehensive numerical analysis of the expected performance of the Earth Explorer 11 (EE11) SeaSTAR mission candidate in the case of idealised and realistic 2D ocean currents and wind fields. A Bayesian framework derived from satellite scatterometry is adapted and applied to SeaSTAR's bespoke inversion scheme that simultaneously retrieves total surface current vectors (TSCV) and ocean surface vector winds (OSVW). The results confirm the excellent performance of the EE11 SeaSTAR concept, with Root Mean Square Errors (RMSE) for TSCV and OSVW at 1 × 1 km2 resolution consistently better than 0.1 m/s and 0.4 m/s, respectively. The analyses highlight some performance degradation in some relative wind directions, particularly marked at near range and low wind speeds. Retrieval uncertainties are also reported for several variations around the SeaSTAR baseline three-azimuth configuration, indicating that RMSEs improve only marginally (by ∼0.01 m/s for TSCV) when including broadside Radial Surface Velocity or broadside dual-polarisation data in the inversion. In contrast, our results underscore (a) the critical need to include broadside Normalised Radar Cross Section data in the inversion; (b) the rapid performance degradation when broadside incidence angles become steeper than 20° from nadir; and (c) the benefits of maintaining ground squint angle separation between fore and aft lines-of-sight close to 90°. The numerical results are consistent with experimental performance estimates from airborne data and confirm that the EE11 SeaSTAR concept satisfies the requirements of the mission objectives. [ABSTRACT FROM AUTHOR]

Photocatalysts based on single atoms (SAs) modification can lead to unprecedented reactivity with recent advances. However, the deactivation of SAs‐modified photocatalysts remains a critical challenge in the field of photocatalytic CO2 reduction. In this study, we unveil the detrimental effect of CO intermediates on Cu single atoms (Cu‐SAs) during photocatalytic CO2 reduction, leading to clustering and deactivation on TiO2. To address this, we developed a novel Cu‐SAs anchored on Au porous nanoparticles (CuAu‐SAPNPs‐TiO2) via a vectored etching approach. This system not only enhances CH4 production with a rate of 748.8 μmol ⋅ g−1 ⋅ h−1 and 93.1 % selectivity but also mitigates Cu‐SAs clustering, maintaining stability over 7 days. This sustained high performance, despite the exceptionally high efficiency and selectivity in CH4 production, highlights the CuAu‐SAPNPs‐TiO2 overarching superior photocatalytic properties. Consequently, this work underscores the potential of tailored SAs‐based systems for efficient and durable CO2 reduction by reshaping surface adsorption dynamics and optimizing the thermodynamic behavior of the SAs. [ABSTRACT FROM AUTHOR]

Photocatalysts based on single atoms (SAs) modification can lead to unprecedented reactivity with recent advances. However, the deactivation of SAs‐modified photocatalysts remains a critical challenge in the field of photocatalytic CO2 reduction. In this study, we unveil the detrimental effect of CO intermediates on Cu single atoms (Cu‐SAs) during photocatalytic CO2 reduction, leading to clustering and deactivation on TiO2. To address this, we developed a novel Cu‐SAs anchored on Au porous nanoparticles (CuAu‐SAPNPs‐TiO2) via a vectored etching approach. This system not only enhances CH4 production with a rate of 748.8 μmol ⋅ g−1 ⋅ h−1 and 93.1 % selectivity but also mitigates Cu‐SAs clustering, maintaining stability over 7 days. This sustained high performance, despite the exceptionally high efficiency and selectivity in CH4 production, highlights the CuAu‐SAPNPs‐TiO2 overarching superior photocatalytic properties. Consequently, this work underscores the potential of tailored SAs‐based systems for efficient and durable CO2 reduction by reshaping surface adsorption dynamics and optimizing the thermodynamic behavior of the SAs. [ABSTRACT FROM AUTHOR]

The exploitation and utilization of coal resources have significantly contributed to global energy security. However, this mining activity has inflicted considerable damage on the ecological environment, particularly on the Tibetan Plateau, where the impact on ecosystems may be even more detrimental. The implementation of high-intensity mining activities leads to rapid changes in land cover/land use. Consequently, it is essential to accurately and effectively monitor mining disturbances. In this study, we propose an approach to capture surface mining disturbances using spatial–temporal rules and time series stacks of Landsat data. First, a time series of annual mining disturbance probability was generated based on Landsat temporal-spectral metrics and random forest. Second, the Landsat-based detection of Trends in Disturbance and Recovery (LandTrendr) algorithm was employed to segment the time series and detect breakpoints. Finally, mining disturbances were captured by further restricting the output of LandTrendr based on spatial–temporal rules of mining disturbances. This approach was applied and evaluated in the Muli mining area of the northeastern Tibetan Plateau, which experienced large-scale and rapid mining disturbances from 2004 to 2014, and identified a disturbed mining area of 43.62 km2. The mining sites have been reclaimed after mining, and all reclamation work was done after 2016, with a total reclaimed area of 22.28 km2. The validation results indicated that the overall accuracy of mining disturbance and reclamation mapping ranges from 0.7333 to 0.8667, and the F1 scores for mining disturbances and reclamation range from 0.7551 to 0.8723. This study provides a reliable framework for monitoring mining disturbances and reclamation in surface mines, promising to be useful in realizing disturbance monitoring in surface mines for a wide range of mineral types. [ABSTRACT FROM AUTHOR]

Photocatalysts based on single atoms (SAs) modification can lead to unprecedented reactivity with recent advances. However, the deactivation of SAs‐modified photocatalysts remains a critical challenge in the field of photocatalytic CO2 reduction. In this study, we unveil the detrimental effect of CO intermediates on Cu single atoms (Cu‐SAs) during photocatalytic CO2 reduction, leading to clustering and deactivation on TiO2. To address this, we developed a novel Cu‐SAs anchored on Au porous nanoparticles (CuAu‐SAPNPs‐TiO2) via a vectored etching approach. This system not only enhances CH4 production with a rate of 748.8 μmol ⋅ g−1 ⋅ h−1 and 93.1 % selectivity but also mitigates Cu‐SAs clustering, maintaining stability over 7 days. This sustained high performance, despite the exceptionally high efficiency and selectivity in CH4 production, highlights the CuAu‐SAPNPs‐TiO2 overarching superior photocatalytic properties. Consequently, this work underscores the potential of tailored SAs‐based systems for efficient and durable CO2 reduction by reshaping surface adsorption dynamics and optimizing the thermodynamic behavior of the SAs. [ABSTRACT FROM AUTHOR]

Photocatalysts based on single atoms (SAs) modification can lead to unprecedented reactivity with recent advances. However, the deactivation of SAs‐modified photocatalysts remains a critical challenge in the field of photocatalytic CO2 reduction. In this study, we unveil the detrimental effect of CO intermediates on Cu single atoms (Cu‐SAs) during photocatalytic CO2 reduction, leading to clustering and deactivation on TiO2. To address this, we developed a novel Cu‐SAs anchored on Au porous nanoparticles (CuAu‐SAPNPs‐TiO2) via a vectored etching approach. This system not only enhances CH4 production with a rate of 748.8 μmol ⋅ g−1 ⋅ h−1 and 93.1 % selectivity but also mitigates Cu‐SAs clustering, maintaining stability over 7 days. This sustained high performance, despite the exceptionally high efficiency and selectivity in CH4 production, highlights the CuAu‐SAPNPs‐TiO2 overarching superior photocatalytic properties. Consequently, this work underscores the potential of tailored SAs‐based systems for efficient and durable CO2 reduction by reshaping surface adsorption dynamics and optimizing the thermodynamic behavior of the SAs. [ABSTRACT FROM AUTHOR]

State-of-the-art Earth system models exhibit large biases in their representation of the tropical Atlantic hydrography, with potential large impacts on both climate and ocean biogeochemistry projections. This study investigates how biases in model physics influence marine biogeochemical processes in the tropical Atlantic using the Norwegian Earth System Model (NorESM). We assess four different configurations of NorESM: NorESM1 is taken as benchmark (NorESM1-CTL) that we compare against the simulations with (1) a physical bias correction and against (2 and 3) two configurations of the latest version of NorESM with improved physical and biogeochemical parameterizations with low and intermediate atmospheric resolutions, respectively. With respect to NorESM1-CTL, the annual-mean sea surface temperature (SST) bias is reduced largely in the first simulation and comparably in the third simulation in the equatorial and southeastern Atlantic. In addition, the SST seasonal cycle is improved in all three simulations, resulting in more realistic development of the Atlantic Cold Tongue in terms of location and timing. Corresponding to the cold tongue seasonal cycle, the marine primary production in the equatorial Atlantic is also improved, and the Atlantic summer bloom is particularly well represented during June to September in all three simulations. The more realistic summer bloom can be related to the well-represented shallow thermocline and associated nitrate supply from the subsurface ocean at the Equator. The climatological intense outgassing of air–sea CO2 flux in the western basin is also improved in all three simulations. Improvements in the climatology mean state also lead to better representation of primary production and air–sea CO2 interannual variability associated with the Atlantic Niño and Niña events. We stress that the physical process and its improvement are responsible for modelling the marine biogeochemical process because the first simulations, where only climatological surface ocean dynamics are corrected, provide more improvements in terms of marine biogeochemical processes. [ABSTRACT FROM AUTHOR]

Motivated by clinical problems of titanium implant degradation, we developed a workflow that enabled assessment of surface oxide dynamics as a function of clinical interventions and inflammation conditions. We found that mechanical damage led to decrease of stoichiometric TiO2 ratio in the passivation oxide film and further resulted in accelerated degradation under inflammatory anaerobic conditions. This method can be employed for the assessment of surface oxides to monitor implant safety. [ABSTRACT FROM AUTHOR]

Recent reports on sub‐terahertz (THz) generation from a laser‐irradiated wire might have evaded the most essential contents of the wire radiation dynamics. Here, the origin of terahertz generation from a metal wire is revisited and a comprehensive diagnosis of the terahertz radiation from a 100 µm‐diameter tungsten wire irradiated by an intense femtosecond laser is implemented. For the first time, the long‐neglected but more efficient high‐frequency terahertz radiation is experimentally observed of which the spectra, polarization, tunability, and wire‐length‐dependent intensification are investigated comprehensively. A new picture of the wire radiation dynamics is presented to reveal the origin of the extreme terahertz surface wave, its evolution, and radiation mechanism. This extremely intense and ultrashort half‐cycle surface wave is spontaneously induced by a laser‐driven transient charge‐separation field and evolves into a multi‐cycle surface wakefield structure as it propagates along the wire owing to the self‐interaction between the surface wave and its carrier, the surface current. By manipulating the coupling and transport dynamics of the surface wave on the wire, tunable and intensified THz radiation covering a wide range from 0.1 to 20 THz has been realized, paving the way for broad applications such as terahertz acceleration, bio‐medicine, nonlinear THz science and beyond. [ABSTRACT FROM AUTHOR]

Spatially explicit, near real time information on surface water dynamics is critical for understanding changes in water resources, and for long-term water security planning. The distribution of surface water across the African continent since 1984 and updated as every new Landsat scene becomes available is presented here, and validated for the continent for the first time. We applied the Water Observations from Space (WOfS) algorithm, developed and well-tested in Australia, to every Landsat scene acquired over Africa since the mid 1980s to provide spatial information on surface water dynamics over the past 30+ years. We assessed the accuracy of WOfS using aerial and satellite imagery. Four regional geospatial organisations, coordinated through the Digital Earth Africa Product Development Task Team, conducted the validation campaign and provided both the regional expertise and experience required for a continental-scale validation effort. We assessed whether the point was wet, dry, or cloud covered, for each of the 12 months in 2018, resulting in 34,800 labelled observations. As waterbodies larger than 100 km² are easy to identify with Landsat resolution data and can thus boost accuracy, these were masked out. The resulting overall accuracy of the water classification was 82%. WOfS in Africa is expected to be used by ministries and departments of agriculture and water across the continent, by international organisations, academia, and the private sector. A large-scale collaborative effort, which included regional and technical skills spanning two continents was required to create a service that is regionally accurate and is both hosted on, and implemented operationally from, the African continent. [ABSTRACT FROM AUTHOR]

The reconstructed surface structure of Co‐based spinel oxides serves as the active site for oxygen evolution reaction (OER). However, the structural complexity of spinel oxides and surface dynamics during the OER hinder the understanding of the reconstruction mechanism and electronic structure of the active site. In this study, spinel Co3O4@(CoFeV)3O4 nanocube (CoFeV) is reported, a (001) facet‐defined spinel oxide comprising Co, Fe, and V deposited on the Co3O4 nanocube template to exclude facet‐dependent factors. Introducing highly dissoluble V cations accelerates the reconstruction process to enhance the electrocatalytic activity. CoFeV exhibited enhanced electrocatalytic activity (266 mV at 10 mA cm−2 in 1 M KOH) and durability (maintained stable electrocatalytic activity during a 200 h chronopotentiometry (CP) test at 100 mA cm−2) with significantly enlarged electrochemically active surface area (ECSA). The experimental and theoretical results demonstrated that V dissolution during catalysis induced oxygen vacancies, accelerating the surface reconstruction to highly active oxyhydroxide. Consequently, the anion exchange membrane water electrolyzer (AEMWE) of CoFeV as the anode exhibited a remarkable performance of 6.19 A cm−2 at 2.0 Vcell in 1 M KOH and robust durability for 96 h at a constant current density of 500 mA cm−2. [ABSTRACT FROM AUTHOR]

The mechanism that causes the rapid uplift and active magmatism of the Hoh-Xil Basin in the northern Tibetan Plateau and hence the outward growth of the proto-plateau is highly debated, more specifically, over the relationship between deep dynamics and surface uplift. Until recently the Hoh-Xil Basin remained uncovered by seismic networks due to inaccessibility. Here, based on linear seismic arrays across the Hoh-Xil Basin, we present a three-dimensional S-wave velocity (VS) model of the crust and uppermost mantle structure beneath the Tibetan Plateau from ambient noise tomography. This model exhibits a widespread partially molten crust in the northern Tibetan Plateau but only isolated pockets in the south manifested as low-VS anomalies in the middle crust. The spatial correlation of the widespread low-VS anomalies with strong uppermost mantle low-VS anomalies and young exposed magmatic rocks in the Hoh-Xil Basin suggests that the plateau grew through lithospheric mantle removal and its driven magmatism. [ABSTRACT FROM AUTHOR]

In contrast to other swimming modes, the motions of fins in the labriform mode can be categorized into the drag-based mode and the lift-based mode, which differ in terms of the thrust generation mechanisms. This variance in thrust generation mechanisms gives the labriform mode unique advantages in underwater propulsion. The term labriform indicates that propulsion occurs due to oscillatory movements of pectoral fins. Herein, to identify the key features of labriform locomotion, numerical simulations of a self-propelled biomimetic robotic fish with a Reynolds number (Re) of up to 3 000 000 in the labriform mode are performed. This study includes a detailed analysis of swimming performance and hydrodynamic mechanisms and their connection to three-dimensional vortex dynamics. Compared with the drag-based mode, the fish is observed to cruise faster and swim more smoothly in the lift-based mode. This study also finds that the pectoral fin can produce continuous thrust during one cycle in lift-based mode but can only generate thrust during the power stroke in the drag-based mode. By connecting vortex dynamics and surface pressure, the results show that the leading-edge vortices generated by pectoral fins are associated with most of the thrust production in both motion modes. The analysis of the vortex structure shows that the pectoral fins shed one vortex ring in one cycle of the drag-based mode and two vortex rings in one cycle of the lift-based mode. Our results provide new insights regarding the self-propelled swimming mechanism of biomimetic robotic fish with different labriform propulsion modes. [ABSTRACT FROM AUTHOR]

The results of an analysis of the images of surface heat fluxes obtained from satellite microwave and infrared radiometric measurements in the areas of the origination of hurricanes in the Gulf of Mexico and tropical Atlantic are presented. It is stated that the intensity of the latent and sensible heat fluxes over 4–5 days preceding the origination of hurricanes increases and the fluxes are localized in certain areas—hurricane centers. The maximum values of the heat fluxes are reached simultaneously with the transition of tropical formations from the stage of a tropical storm to the stage of a tropical hurricane. [ABSTRACT FROM AUTHOR]

In volcanic belts, magma influx into magma chambers generates excess pressure, amplifying the initial stress field to cause crustal deformation with significant ground displacements, which manifests in topographic relief. Quantifying such volcano-driven ground surface displacements is a fundamental requirement to embark on a criticality analysis of volcanotectonic events and associated hazard monitoring strategies. This study theoretically examines the underlying dynamics of surface displacements in a volcanic plumbing system comprising multiple magma chambers. The classical Mogi equation is extended to derive a set of analytical solutions to evaluate surface displacements as a function of separations between two off-axis chambers, measured along both horizontal and vertical directions. The resulting surface displacement plots, from the analytical solutions are compared with those calculated from a set of finite element (FE) model simulations run with the same parameters considered for the analytical formulations. Both the analytical and FE results suggest that horizontal (Sh) and vertical (Sv) separations of magma chambers largely control the vertical (Uz) and lateral (Ur) ground-displacement components. Spatially varying Uz attains its peak value at a specific location above the chambers, but increasing horizontal separation (Sh ~ 10 km) transforms the single-peak Uz pattern to a weakly developed double-peak Uz pattern, which eventually give way to two prominent high-amplitude peaks above the chambers when Sh ~ 25 km. Similarly, a large vertical separation (Sv ~ 6 km) yields double peaks in the Uz profile, which merge to form a single peak for small Sv (~ 1.5 km). The FE model results are used to map the stress fields around the two magma chambers to show that inter-chamber mechanical interaction can influence the deformation behaviour around the chambers, depending on Sh and Sv magnitudes. Finally, the model estimates are evaluated using available reports on the naturally occurring volcanoes: Teide volcano (Tenerife, Spain) and Long Valley Caldera (USA). [ABSTRACT FROM AUTHOR]

Flexible electrochemical sensors can adhere to any bendable surface with conformal contact, enabling continuous data monitoring without compromising the surface's dynamics. Among various materials that have been explored for flexible electronics, metal–organic frameworks (MOFs) exhibit dynamic responses to physical and chemical signals, offering new opportunities for flexible electrochemical sensing technologies. This review aims to explore the role of electrocatalysis in MOF films specifically designed for flexible electrochemical sensing applications, with a focus on their design, fabrication techniques, and applications. We systematically categorize the design and fabrication techniques used in preparing MOF films, including in situ growth, layer-by-layer assembly, and polymer-assisted strategies. The implications of MOF-based flexible electrochemical sensors are examined in the context of wearable devices, environmental monitoring, and healthcare diagnostics. Future research is anticipated to shift from traditional microcrystalline powder synthesis to MOF thin-film deposition, which is expected to not only enhance the performance of MOFs in flexible electronics but also improve sensing efficiency and reliability, paving the way for more robust and versatile sensor technologies. [ABSTRACT FROM AUTHOR]

Hydrogen atom scattering on metal surfaces is investigated based on a simplified Newns–Anderson model. Both the nuclear and electronic degrees of freedom are treated quantum mechanically. By partitioning all the surface electronic states as the bath, the hierarchical equations of motion method for the fermionic bath is employed to simulate the scattering dynamics. It is found that, with a reasonable set of parameters, the main features of the recent experimental studies of hydrogen atom scattering on metal surfaces can be reproduced. Vibrational states on the chemisorption state whose energies are close to the incident energy are found to play an important role, and the scattering process is dominated by a single-pass electronic transition forth and back between the diabatic physisorption and chemisorption states. Further study on the effects of the atom-surface coupling strength reveals that, upon increasing the atom-surface coupling strength, the scattering mechanism changes from typical nonadiabatic transitions to dynamics in the electronic friction regime. [ABSTRACT FROM AUTHOR]

[Display omitted] The anchoring sites of metal single atoms are closely related to photogenerated carrier dynamics and surface reactions. Achieving smooth photogenerated charge transfer through precise design of single-atom anchoring sites is an effective strategy to enhance the activity of photocatalytic hydrogen evolution. In this study, Pt single atoms were loaded onto ultra-thin carbon nitride with two-coordination nitrogen vacancies (V N2c -UCN-Pt) and ultra-thin carbon nitride with three-coordination nitrogen vacancies (V N3c -UCN-Pt). This paper investigated the photocatalytic hydrogen evolution performance and photogenerated carrier behavior of Pt single atoms at different anchoring sites. Surface photovoltage measurements indicated that V N2c -UCN-Pt exhibits a superior carrier separation efficiency compared to V N3c -UCN-Pt. More importantly, the surface photovoltage signal under the presence of H 2 O molecules revealed a significant decrease. Theoretical calculations suggest that V N2c -UCN-Pt exhibits superior capabilities in adsorbing and activating H 2 O molecules. Consequently, the photocatalytic hydrogen evolution efficiency of V N2c -UCN-Pt reaches 1774 µmol g−1h−1, which is 1.8 times that of V N3c -UCN-Pt with the same Pt loading. This work emphasized the structure–activity relationship between single-atom anchoring sites and photocatalytic activity, providing a new perspective for designing precisely dispersed single-atom sites to achieve efficient photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

Hydrogen evolution reaction (HER) by splitting water is a key technology toward a clean energy society, where Pt-based catalysts were long known to have the highest activity under acidic electrochemical conditions but suffer from high cost and poor stability. Here, we overview the current status of Pt-catalyzed HER from a theoretical perspective, focusing on the methodology development of electrochemistry simulation, catalytic mechanism, and catalyst stability. Recent developments in theoretical methods for studying electrochemistry are introduced, elaborating on how they describe solid–liquid interface reactions under electrochemical potentials. The HER mechanism, the reaction kinetics, and the reaction sites on Pt are then summarized, which provides an atomic-level picture of Pt catalyst surface dynamics under reaction conditions. Finally, state-of-the-art experimental solutions to improve catalyst stability are also introduced, which illustrates the significance of fundamental understandings in the new catalyst design. [ABSTRACT FROM AUTHOR]

In this work, we have used ab initio molecular dynamics at room temperature to study the adsorption and dissociation of a thin water film on Co3O4 (111) surfaces, considering the O-rich and Co-rich terminations named as the A-type and B-type surface terminations, respectively. We investigate the occupation of active sites, the hydrogen bond network at the interface and the structural response of the surfaces to water adsorption. On both terminations, water adsorbs via a partial dissociative mode. The contact layer is populated by molecular water as well as OH groups and surface OH resulting from proton transfer to the surface. The B-termination is more reactive, with a higher degree of dissociation in the contact layer with water (46%). On the B-terminated surface, water barely adsorbs on the Co2+ sites and almost exclusively binds and dissociates on the Co3+ sites. The interaction with the surface consists mostly of Co3+–Ow bonds and proton transfer exclusively to the 3-fold unsaturated surface Os1. Hydrogen bonds between water molecules in the aqueous film dominate the hydrogen bond network and no hydrogen bonds between water and the surface are observed. The A-terminated surface is less reactive. Water binds covalently on Co2+ sites, with a dissociation degree of 13%. Proton transfer occurs mostly on the 3-fold unsaturated surface oxygens Os1. Besides, short-lived surface OH arising from proton transfer to 3-fold unsaturated surface oxygens Os2 is observed. H-bonding to surface Os1 and Os2 constitutes 12.7% and 19.8% of the H-bond network, respectively, and the largest contribution is found among the water molecules (67.4%). On both surfaces, the coordination number of the active sites drives the relaxations of the outermost atom positions to the their bulk counterparts. The occupation of active sites on B-termination could reach up to 3 adsorbates per Co3+ leading to a binding motif in which the Co is octahedrally coordinated and which was observed experimentally. [ABSTRACT FROM AUTHOR]

The protein dynamical transition at ~200 K, where the biomolecule transforms from a harmonic, non-functional form to an anharmonic, functional state, has been thought to be slaved to the thermal activation of dynamics in its surface hydration water. Here, by selectively probing the dynamics of protein and hydration water using elastic neutron scattering and isotopic labeling, we found that the onset of anharmonicity in the two components around 200 K is decoupled. The one in protein is an intrinsic transition, whose characteristic temperature is independent of the instrumental resolution time, but varies with the biomolecular structure and the amount of hydration, while the one of water is merely a resolution effect. [ABSTRACT FROM AUTHOR]

Water conservation is a crucial indicator that measures the available water resources needed for maintaining regional ecological services and socioeconomic development. The Yiluo River Basin plays an essential role in water conservation in the Yellow River Basin, which is one of the most important river basins with vulnerable ecological conditions and a large population in China. However, previous studies have a limited understanding of the distribution of water conservation in the Yiluo River Basin. To address this knowledge gap, we developed a SWAT model to evaluate water conservation in the Yiluo River Basin with high spatial and temporal details on a monthly scale. From a monthly perspective, water conservation accumulation primarily took place in July (54.6 mm), August (23.5 mm), and September (33.2 mm), which are in the flood season. From 1966 to 2018, we found a significant 47% reduction in basin-wide water conservation, and the reduction was primarily influenced by meteorological conditions and underlying surface dynamics. The results of the temporal correlation analysis identified precipitation as the most significant factor influencing water conservation, while the spatial correlation analysis revealed that potential evapotranspiration, vegetation, and elevation had the highest spatial correlation with water conservation. By combining SWAT outputs on the HRU (hydrological response unit) scale with the spatial distribution of HRUs, the study achieved the visualization of the spatial distribution of water conservation, identifying Luonan County, Luanchuan County, and Luoning County as the key regions that experienced water conservation decline over the past decades. These findings advance our understanding of the distributions of water conservation and their key driving factors in the study area and provide valuable policy implications to support ecological protection and water resource management in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

The concept of a lithiophilic electrode proves inadequate in describing carbon‐based electrode materials due to their substantial mismatch in surface energy with lithium metal. However, their notable capacity for lithium chemisorption can increase active lithium concentration required for nucleation and growth, thereby enhancing the electrochemical performance of lithium metal anodes (LMAs). In this study, we elucidate the effects of the supersaturated electrode which has high active lithium capacity around equilibrium lithium potential on LMAs through an in‐depth electrochemical comparison using two distinct carbon electrode platforms with differing carbon structures but similar two‐dimensional morphologies. In the supersaturated electrode, both the dynamics and thermodynamic states involved in lithium nucleation and growth mechanisms are significantly improved, particularly under continuous current supply conditions. Furthermore, the chemical structures of the solid‐electrolyte‐interface layers (SEIs) are greatly influenced by the elevated surface lithium concentration environment, resulting in the formation of more conductive lithium‐rich SEI layers. The improved dynamics and thermodynamics of surface lithium, coupled with the formation of enhanced SEI layers, contribute to higher power capabilities, enhanced Coulombic efficiencies, and improved cycling performances of LMAs. These results provide new insight into understanding the enhancements in heterogeneous lithium nucleation and growth kinetics on the supersaturated electrode. [ABSTRACT FROM AUTHOR]

Surface charges play a fundamental role in physics and chemistry, in particular in shaping the catalytic properties of nanomaterials. However, tracking nanoscale surface charge dynamics remains challenging due to the involved length and time scales. Here, we demonstrate time-resolved access to the nanoscale charge dynamics on dielectric nanoparticles using reaction nanoscopy. We present a four-dimensional visualization of the spatiotemporal evolution of the charge density on individual SiO2 nanoparticles under strong-field irradiation with femtosecond-nanometer resolution. The initially localized surface charges exhibit a biexponential redistribution over time. Our findings reveal the influence of surface charges on surface molecular bonding through quantum dynamical simulations. We performed semi-classical simulations to uncover the roles of diffusion and charge loss in the surface charge redistribution process. Understanding nanoscale surface charge dynamics and its influence on chemical bonding on a single-nanoparticle level unlocks an increased ability to address global needs in renewable energy and advanced health care. [ABSTRACT FROM AUTHOR]

The duality between deformations of elastic bodies and noninertial flows in viscous liquids has been a guiding principle in decades of research. However, this duality is broken when a spheroidal or other doubly curved liquid film is suddenly forced out of mechanical equilibrium, as occurs, e.g., when the pressure inside a liquid bubble drops rapidly due to rupture or controlled evacuation. In such cases, the film may evolve through a noninertial yet geometrically nonlinear surface dynamics, which has remained largely unexplored. We reveal the driver of such dynamics as temporal variations in the curvature of the evolving surface. Focusing on the prototypical example of a floating bubble that undergoes rapid depressurization, we show that the bubble surface evolves via a topological instability and a subsequent front propagation, whereby a small planar zone that includes a singular flow structure, analogous to a disclination in elastic systems, nucleates spontaneously and expands in the spherically shaped film. This flow pattern brings about hoop compression and triggers another, symmetrybreaking instability to the formation of radial wrinkles that invade the flattening film. Our analysis reveals the dynamics as a nonequilibrium branch of "jellium" physics, whereby a rate-of-change of surface curvature in a viscous film is akin to charge in an electrostatic medium that comprises polarizable and conducting domains. We explain key features underlying recent experiments and highlight a qualitative inconsistency between the prediction of linear stability analysis and the observed "wavelength" of surface wrinkles. [ABSTRACT FROM AUTHOR]

Real-time detection of intermediate species and final products at the surface and near-surface in interfacial solid–gas reactions is critical for an accurate understanding of heterogeneous reaction mechanisms. In this article, an experimental method that can simultaneously monitor the ultrafast dynamics at the surface and above the surface in photoinduced heterogeneous reactions is presented. This method relies on a combination of mass spectrometry and femtosecond pump–probe spectroscopy. As a model system, the photoinduced reaction of methyl iodide on and above a cerium oxide surface is investigated. The species that are simultaneously detected from the surface and gas-phase present distinct features in the mass spectra, such as a sharp peak followed by an adjacent broad shoulder. The sharp peak is attributed to the species detected from the surface, while the broad shoulder is due to the detection of gas-phase species above the surface, as confirmed by multiple experiments. By monitoring the evolution of the sharp peak and broad shoulder as a function of the pump–probe time delay, transient signals are obtained that describe the ultrafast photoinduced reaction dynamics of methyl iodide on the surface and in the gas-phase. Finally, SimION simulations are performed to confirm the origin of the ions produced on the surface and in the gas-phase. [ABSTRACT FROM AUTHOR]

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The observation of precursory signals of the 2021 Chamoli rock–ice avalanche provides an opportunity to investigate the multidisciplinary analysis approach of rock failure. On 7 February 2021, a huge rock–ice mass detached from the Raunthi peak at Chamoli district in Uttarakhand, India. The tragic catastrophe resulted in more than 200 deaths and significant economic losses. Here, we analyse radon concentration and seismic signals to characterise the potential precursory anomalies prior to the detachment. Continuous peaks of radon anomalies were observed from the afternoon of 5 to 7 February and decreased suddenly after the event, while a cumulative number of seismic tremors and amplitude variations are more intensified ~2.30 h before the main event, indicating a static to dynamic phase change within the weak zone. This study not only characterises abnormal signals but also models the rock failure mechanisms. The analysis unveils three time‐dependent nucleation phases, physical mechanisms of signal generation and a complete scenario of physical factors that affected the degree of criticality of slope failure. The results of this study suggest gradual progression of rock cracks/joints, subsequent material creep and slip advancement acceleration preceded the final failure. Furthermore, the study highlights the importance of an early warning system to mitigate the impact of events like the 2021 Chamoli rock–ice avalanche. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) have emerged as leading‐edge research in the field of photocatalysis due to outstanding photocatalytic performance, maximum atomic utilization efficiency, and well‐defined catalytic active sites. However, the singular functionality of active sites in SACs restricts their applications in complex redox reactions involving multiple intermediates and reaction pathways. To circumvent this limitation, a second site comprising single atoms (SA), alloys, clusters, or nanoparticles is proposed to establish SA‐based dual‐site photocatalysts (SA DSPs). While maintaining 100% atomic utilization, the second site and site–site collaboration endow SA DSPs with superior photocatalytic activities to surpass those of SACs. In this review, the latest investigations on SA DSPs featuring diverse compositions, electronic and geometric configurations, site–site collaboration, and metal–support interactions are summarized. Thereafter, the mechanisms underlying enhanced photocatalytic activities are elucidated regarding the roles of the dual sites in charge‐carrier dynamics and surface reactivity. Furthermore, the state‐of‐the‐art applications in photocatalytic hydrogen evolution, CO2 reduction, and methane oxidation, etc., over SA DSPs are discussed. It is anticipated that this review will offer insights into precise control and design of dual sites in photocatalysts, thereby advancing photocatalysis toward commercial viability. [ABSTRACT FROM AUTHOR]

In this manuscript, we provide a general theory for how surface phonons couple to molecular adsorbates. Our theory maps the extended dynamics of a surface's atomic vibrational motions to a generalized Langevin equation, and by doing so captures these dynamics in a single quantity: the non-Markovian friction. The different frequency components of this friction are the phonon modes of the surface slab weighted by their coupling to the adsorbate degrees of freedom. Using this formalism, we demonstrate that physisorbed species couple primarily to acoustic phonons while chemisorbed species couple to dispersionless local vibrations. We subsequently derive equations for phonon-adjusted reaction rates using transition state theory and demonstrate that these corrections improve agreement with experimental results for CO desorption rates from Pt(111). [ABSTRACT FROM AUTHOR]