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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]

Topological insulators with high spin–orbit coupling and helically spin-momentum-locked topological surface states (TSSs) can serve as efficient spin current generators for modern spintronics applications. We used the industrial-friendly DC magnetron sputtering technique to fabricate magnetic heterostructures consisting of Bi2Te3 (BT) as a topological insulator and Co60Fe20B20 (CFB) as a magnetic layer and studied the temperature-dependent spin pumping, utilizing out-of-plane ferromagnetic resonance spectroscopy. These results demonstrate that the effective spin-mixing conductance is significantly affected by the contribution of two-magnon scattering (TMS). It is found that the TMS-free effective spin-mixing conductance increases with decreasing temperature. Additionally, results from magneto-transport measurements indicate that the surface coherence length of BT is in accordance with the temperature-dependent effective spin-mixing conductance. This enhancement of effective mixing conductance correlated with the enhancement in the contribution of the TSSs as evaluated using the weak-anti-localization effect. This study provides a deeper understanding of the temperature-dependent spin dynamics in sputtered BT/CFB heterostructures which can serve as a guide for further exploration of such bilayers for topological-based spintronic applications. [ABSTRACT FROM AUTHOR]

We present a combined experimental and theoretical study of surface-related magnetic states in TiO 2. Our experiments on nano-sized thin films of pure TiO 2 have suggested that the observed room-temperature magnetism originates from defects, in particular, from the surface of thin films as well as from point defects, such as oxygen vacancies located mainly at the surface. Clarifying this phenomenon is very important for harnessing magnetic properties of pristine TiO 2 films in future spintronic applications but a detailed experimental investigation is very demanding. Therefore, quantum-mechanical density functional theory calculations were performed for (i) bulk anatase TiO 2 , (ii) bulk-like TiO 2 -terminated vacancy-free (001) surfaces, (iii) vacancy-containing TiO-terminated (001) surfaces, (iv) TiO 0.75 -terminated (001) surfaces with additional 25% surface oxygen vacancies, as well as (v) oxygen-terminated (001)-surfaces. Our fixed-spin-moment calculations identified both the bulk and the bulk-like terminated vacancy-free TiO 2 -terminated (001) surfaces as non-magnetic. In contrast, oxygen vacancies in the case of TiO-terminated and TiO 0.75 -terminated (001) surfaces lead to ferromagnetic and rather complex ferrimagnetic states, respectively. The spin-polarized atoms are the Ti atoms (due to the d -states) located in the surface and sub-surface atomic planes. Last, the O-terminated surfaces are also magnetic due to the surface and sub-surface oxygen atoms and sub-surface Ti atoms (but their surface energy is high). [ABSTRACT FROM AUTHOR]

[Display omitted] Surface states have been a longstanding and sometimes underestimated problem in gallium nitride (GaN) based devices. The instability caused by surface-charge-trapping in GaN-based transistors is practically the same problem faced by the inventors of the silicon (Si) field effect transistors more than half a century ago. Although in Si this problem was eventually solved by oxygen and hydrogen-based passivation, in GaN, such breakthrough has yet to be made. Apparently, some of this surface charge originates in molecules adsorbed on its surface. Here, it is shown that the charge density associated with the GaN yellow band desorbs upon mild heat treatment in vacuum and re-adsorbs on exposure to the air. Selective exposure of GaN to nitrogen dioxide (NO 2) reproduces this surface charge to its original distribution, as does exposure to air. Residual gas analysis of the gases desorbed during heat treatment shows a large concentration of nitric oxide (NO). These observations suggest that selective adsorption of NO 2 is responsible for the surface charge that deleteriously affects the electrical properties of GaN. The physics and chemistry of this NO 2 adsorption, reported here, may open a new path in the search for passivation to improve GaN device reliability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Describing the properties of heterogeneous surfaces via a surface energy function. • The evolution of surface nanobubbles follows the proposed theoretical model. • The contact line slips on the homogeneous regions of the substrate, while pinning always occurs at the boundary sites. • The phase diagram shows the critical nucleation, evolution trends and stable states of the surface nanobubbles. • The nanoscale motion of the contact line can be explained in terms of the forces applied. Surface nanobubbles have revealed a new mechanism of gas–liquid–solid interaction at the nanoscale; however, the nanobubble evolution on real substrates is still veiled, because the experimental observation of contact line motions at the nanoscale is too difficult. This study proposes a theoretical model to describe the dynamics and stability of nanobubbles on heterogeneous substrates. It simultaneously considers the diffusive equilibrium of the liquid–gas interface and the mechanical equilibrium at the contact line, and introduces a surface energy function to express the substrate's heterogeneity. The present model unifies the nanoscale stability and the microscale instability of surface bubbles. The theoretical predictions are highly consistent to the nanobubble morphology on heterogeneous surfaces observed in experiments. As the nanobubbles grow, a lower Laplace pressure leads to weaker gas adsorption, and the mechanical equilibrium can eventually revert to the classical Young-Laplace equation above microscale. The analysis results indicate that both the decrease in substrate surface energy and the increase in gas oversaturation are more conducive to the nucleation and growth of surface nanobubbles, leading to larger stable sizes. The larger surface energy barriers result in the stronger pinning, which is beneficial for achieving stability of the pinned bubbles. The present model is able to reproduce the continual behaviors of the three-phase contact line during the nanobubble evolution, e.g., "pinning, depinning, slipping and jumping" induced by the nanoscale defects. [ABSTRACT FROM AUTHOR]

[Display omitted] Carbon dots have shown a broad application prospect in the fields of sensing and detection, biological imaging, and optoelectronic devices. However, it is still challenging to adopt a simple and green synthesis route and to develop new precursor systems to prepare full-color luminescent carbon dots. This study proposes a mechanism for fine regulation of carbon dot fluorescence spectra based on surface states of C N, C O C, and O H, among which C N play a major role in long wavelength emission while C O C and O H are responsible for the blue shift of emission wavelength. Using 4,4-bipyridine and p-phenylenediamine as precursors in safe and environmentally friendly glycol and water as solvents for the first time, the fine spectral carbon dots with full spectrum luminescence from purple (441 nm) to red (627 nm) were successfully synthesized by simply changing the composition of the reaction solvent and using a short reaction time. Compared with other reports on regulating polychromatic carbon dots, our method is more refined and has a wider distribution of luminescent colors. In addition, the obtained carbon dots based on such surface state luminescence mechanism have shown good application prospects in specific detection of Fe3+and cell labeling. [ABSTRACT FROM AUTHOR]

We study the evolution of band topology under external pressure in rare-earth gadolinium mono-antimonide (GdSb) using first-principles calculations. This material crystallizes in a rocksalt-type structure and shows a structural phase transition (SPT) to a CsCl-type structure at 26.1 GPa. The phonon dispersions are analyzed to ascertain the dynamical stability of this material. We use hybrid density functional theory with the inclusion of spin–orbit coupling to investigate the structural, electronic, and topological phase transitions (TPTs). At ambient pressure, GdSb shows a topologically trivial state which is in agreement with existing experimental reports. The first TPT is observed at 6 GPa of hydrostatic pressure (at the high symmetry X -point) which is verified with the help of single-band inversion and surface state analysis along the (001) plane. The non-zero value of the first Z2 topological invariant and the presence of the Dirac cone also confirm the topological phase of this material. A further increase in pressure to 12 GPa results in two band inversions at Γ - as well as X - points, which corresponds to the trivial nature of GdSb. The same is also verified with (0; 000) values of Z2 topological invariants and a pair of Dirac cones in surface states. It is noted that the crystal symmetries are preserved throughout the study and the TPT values are much lower than the SPT pressure, i.e. 26.1 GPa. [ABSTRACT FROM AUTHOR]

[Display omitted] There is a relationship between the static contact angle of droplets and soap bubbles on flat homogeneous surfaces, therefore, it should be possible to derive a relationship between the static contact angle of a soap bubble on a periodic topographic surface and a droplet on a flat homogeneous surface. A free energy model of the static contact angle of soap bubbles on a topographic surface in the Cassie-Baxter state was derived. Polydimethylsiloxane surfaces of varying area fraction (0.125, 0.250, 0.500, 0.750, and 1.00) and periodic topographies (lined and pillared) were fabricated using 3D printed moulds for pattern transfer. A bubble goniometer was developed to accommodate bubbles of 40,000 ± 5,000 mm3 and 50,000 ± 5,000 mm3 volumes. Then, the static contact angle of bubbles of both volumes were measured on the varying topographic surfaces. The derived predictions imply that the relationship between the static contact angle for bubbles on a flat homogeneous surface and on a composite surface, has the same form as the Cassie-Baxter equation for a droplet. The experimental results for the measured static contact angle for both bubble volumes on the varying surfaces had good agreement with the predicted trends. [ABSTRACT FROM AUTHOR]

Surface fluxes and states can recur and remain consistent across various spatial and temporal scales, forming space‐time patterns. Quantifying and understanding the observed patterns is desirable, as they provide information about the dynamics of the processes involved. This study introduces the empirical spatio‐temporal covariance function and a corresponding parametric covariance function as tools to identify and characterize spatio‐temporal patterns in remotely sensed fields. The method is demonstrated using 2 km hourly GOES‐16/17 land surface temperature (LST) data over the Contiguous United States by splitting the area into 1.0° × 1.0° domains. The summer day‐time LST ESTCFs for 2018 to 2022 are derived for each domain, and a parametric covariance model is fitted. Clustering analysis is applied to detect areas with similar spatio‐temporal LST patterns. Six main zones within CONUS are identified and characterized based on their variance and temporal and spatial characteristic length scales (i.e., scales for which the temperature variations are temporally and spatially related), respectively: (a) Eastern plains with 3 K2, ∼6 hr, and 0.15°, (b) Gulf of California with 60 K2, ∼8 hr, and 0.34°, (c) mountains and coasts transition 1 with 16 K2, ∼11 hr, and 0.25°, (d) central US, Midwest, and South cities with 5.5 K2, ∼8 hr, and ∼0.2°, (e) mountains and coasts transition 2 with ∼10 K2, ∼8 hr, and 0.2°, and (f) largest mountains and coastlines with ∼19 K2, ∼13 hr, and 0.3°. The tools introduced provide a pathway to formally identify and summarize the spatio‐temporal patterns observed in remotely sensed fields and relate those to more complex processes within the Soil‐Vegetation‐Atmosphere System. Plain Language Summary: Specific processes on Earth's surface, like heat and water fluxes and air movement, often exhibit coherent patterns across space and time. Figuring out where these patterns occur can be helpful as they can aid to explain how the underlying physical processes work. This research introduces a new tool to find and describe these patterns and applies it to temperature data derived from satellites. The United States is divided into smaller areas, and the developed tool is used to analyze the land temperature data within those areas; then, regions with similar temperature patterns are identified. These results help to determine that certain landscape features, like coastlines, mountains, and cities, influence how temperature patterns behave in space, time and both. These tools help us to recognize and describe the patterns we see in satellite observations and ultimately, connect them to more complicated processes happening in the Soil‐Vegetation‐Atmosphere System. Key Points: Space‐time covariance can summarize the space‐time structure of time‐varying spatial fields of surface fluxes and statesThe observed space‐time covariance of land surface temperature (LST) reveals variability in its characteristic length and time scales over the United StatesClustering of the fitted LST space‐time covariance parameters reveals the role of environmental characteristics in the observed patterns [ABSTRACT FROM AUTHOR]

Metal halide perovskites hold a great promise for the development of electroluminescent and down‐conversion light‐emitting diodes (LEDs) owing to their easily tunable optical bandgaps, high photoluminescence quantum yields (PLQYs) and excellent color purity. 3D structural perovskites, valued for their high charge carrier transport capacity, have garnered much attention for high‐performance electroluminescent LEDs with low operating voltages. However, solution‐processed 3D perovskite films always suffer from the generation of defect‐induced trap states on the surfaces and at the grain boundaries, resulting in nonradiative recombination that detracts from the electroluminescence performance. Herein, a 3D/2D heterostructure is constructed to reduce the surface defects of CsPbIxBr3‐x based 3D perovskites by reconfiguring the surface of the 3D perovskite film with fluorine para‐substituted phenethylammonium iodine (p‐FPEAI). The analysis of charge carrier dynamics indicates a decrease in trap‐assisted nonradiative recombination and a notable increase in radiative recombination in the red 3D/2D perovskite films. Consequently, the cutting‐edge deep‐red LEDs with the resultant 3D/2D heterostructure perovskite as the emissive layer demonstrate a high external quantum efficiency of 22.2% and a very stable electroluminescence peak at 674 nm. The proposed p‐FPEAI‐assisted surface engineering is considered a resultful approach for advancing the development of high‐performance LEDs with perovskite heterojunction. [ABSTRACT FROM AUTHOR]

This work describes the first use of blue‐emitting boron‐ and nitrogen‐doped carbon dots (BN‐CDs), rationalizing their photoluminescence behavior in solution and ion‐based thin‐films to prepare white light‐emitting electrochemical cells (LECs). In detail, a cost‐effective and scalable water‐based microwave‐assisted synthesis procedure is set for BN‐CDs featuring an amorphous carbon‐core doped with N and B. While they show a bright (photoluminescence quantum yield of 42%) and excitation‐independent blue‐emission (440 nm) in solution related to emitting n−π* surface states, they are not emissive in thin‐films due to aggregation‐induced quenching. Upon fine‐tuning the film composition (ion‐based host), an excitation dependent emission covering the whole visible range is noted caused by interaction of the ion electrolyte with the peripheral functionalization of the BN‐CDs. Moreover, the efficient energy transfer from the host to the BN‐CDs emitting species enabled good performing LECs with white emission (x/y CIE coordinates of 0.30/0.35, correlated color temperature of 6795 K, color rendering index of 87) and maximum luminance of 40 cd m−2, and stabilities of a few hours. This represents a significant improvement compared to the prior‐art monochromatic CD‐based LECs with similar brightness levels, but stabilities of <1 min. [ABSTRACT FROM AUTHOR]

Downsizing Pt-based catalysts to generate a higher surface-to-volume ratio and maximize atom utilization efficiency has been recognized as an effective strategy to achieve high mass activity. However, the synthesis of homogeneous, ultra-small bimetallic nanoclusters remains a significant challenge due to the difficulties in controlling stoichiometry and surface state control, large miscible gaps between different metals and surface state changes induced by the reaction gas environment. In this paper, bimetallic Pt-based nanoclusters such as PtPd, PtRu, PtCu deposited on carbon black (Vulcan XC72R) were fabricated by the reduction of H 2 plasma.The structure and morphology of those prepared catalysts were revealed by HAADF-STEM, HR-TEM, EDS and XPS. The results indicated the prepared Pt-based nanoclusters displayed high dispersibility and small size owning to the non-equilibrium characteristics of non-thermal plasma (NTPs). The average sizes of PtPd, PtRu and PtCu were 2.06 ± 0.68 nm, 3.66 ± 1.34 nm and 1.98 ± 0.7 nm, respectively. Meanwhile, the synthesized PtPd nanoclusters with the ratio of 3:4 exhibited high catalytic activity in the hydrogen evolution reaction (HER). The Pt 3 Pd 4 /VR-P displayed a low overpotential (19 mV) at 10 mA/cm2 and achieved a high mass activity of 5.4 A/mg for HER in 0.5 M H 2 SO 4 solution, which was 13.8 times higher than those of the commercial Pt/C catalysts. Moreover, the Pt 3 Pd 4 /VR-P demonstrated excellent stability with a negatively shifting about 40 mV after 10,000 cycles at a current density of 10 mA/cm2, which was close to that of JM-Pt/C (32 mV). The results prove NTPs technology is effective for the preparation of bimetallic Pt-based nanoclusters. Non-thermal plasma is an innovative method to prepare Pt-based nanoclusters with high dispersibility and small size. The synthesized Pt 3 Pd 4 nanoclusters with an average size of 2.06 ± 0.68 nm displayed a low overpotential (19 mV) at 10 mA/cm2 and achieved a high mass activity of 5.4 A/mg for HER in 0.5 M H 2 SO 4 solution, which was 13.8 times higher than that of the commercial Pt/C catalysts. [Display omitted] • A plasma fabrication technique for synthesis of Pt-based nanoclusters with high dispersibility and small size was developed. • The average sizes of the prepared PtPd, PtRu and PtCu nanoclusters are 2.06 ± 0.68 nm, 3.66 ± 1.34 nm and 1.98 ± 0.7 nm. • The prepared Pt 3 Pd 4 /VR-P exhibits a low overpotential (19 mV) at 10 mA cm−2 and a high mass activity (5.4 A mg−1) for HER. [ABSTRACT FROM AUTHOR]

Doping of a Mott insulator gives rise to a wide variety of exotic emergent states, from high-temperature superconductivity to charge, spin, and orbital orders. The physics underpinning their evolution is, however, poorly understood. A major challenge is the chemical complexity associated with traditional routes to doping. Here, we study the Mott insulating CrO2 layer of the delafossite PdCrO2, where an intrinsic polar catastrophe provides a clean route to doping of the surface. From scanning tunnelling microscopy and angle-resolved photoemission, we find that the surface stays insulating accompanied by a short-range ordered state. From density functional theory, we demonstrate how the formation of charge disproportionation results in an insulating ground state of the surface that is disparate from the hidden Mott insulator in the bulk. We demonstrate that voltage pulses induce local modifications to this state which relax over tens of minutes, pointing to a glassy nature of the charge order. Metallic surface states on CoO2 and Pd terminated surfaces due to electronic reconstruction have been observed in the CoO2-based delafossites. In contrast, here the authors report an interesting insulating state on the CrO2 terminated surface of PdCrO2 due to charge-disproportionation. [ABSTRACT FROM AUTHOR]

Theoretical and experimental results exploring a half‐Heusler compound TmPdSb with unusual band order and metallic surface states are presented. Typically, the half‐Heusler systems exhibit topological features in a semimetallic state, and trivial ones in an insulating state. Topological properties of the most of half‐Heusler systems are related to the band inversion around the Fermi level, similar to this observed in CdTe/HgTe systems. In the case of TmPdSb, the gapped electronic band structure with "band inversion" in the conductance band is observed, while the slab‐like system realized metallic surface states. The bulk insulating nature of the compound is corroborated by means of electrical transport measurements. The experimental data reveal several features due to the presence of metallic surface states, such as linear magnetoresistance and weak‐antilocalization effect, characterized by enhanced coherence length and a very large number of surface conductive channels. The findings reveal new features of the rare‐earth bearing half‐Heusler. [ABSTRACT FROM AUTHOR]

Spin and valley are two fundamental properties of electrons in crystals. The similarity between them is well understood in valley-contrasting physics established decades ago in two-dimensional (2D) materials like graphene-- with broken inversion symmetry, the two valleys in graphene exhibit opposite orbital magnetic moments, similar to the spin-1/2 behaviors of electrons, and opposite Berry curvature that leads to a half topological charge. However, valley-contrasting physics has never been explored in 3D crystals. Here, we develop a 3D acoustic crystal exhibiting 3D valley-contrasting physics. Unlike spin that is fundamentally binary, valley in 3D can take six different values, each carrying a vortex in a distinct direction. The topological valley transport is generalized from the edge states of 2D materials to the surface states of 3D materials, with interesting features including robust propagation, topological refraction, and valley-cavity localization. Our results open a new route for wave manipulation in 3D space. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion Skin elasticity, which is vital for a youthful appearance, depends on the elastic fibres in the dermis. However, these fibres deteriorate with ageing, resulting in wrinkles and sagging. Changes that occur in the elastic fibres in living human skin and the relationship between elastic fibres and the state of the skin surface remain unclear. Therefore, it is necessary to verify the relationship between elastic fibres and skin elasticity. In this study, we investigated the association of the elastic fibre structure with skin elasticity and stratum corneum protein content in living human skin.Thirty‐five female volunteers aged 25–66 years were included in this study. Elastic fibres were observed using a multiphoton scanning laser biomicroscope. Skin elasticity was measured using a Cutometer, and stratum corneum proteins (Heat‐shock protein 27 [HSP27] and galectin‐7 [Gal‐7]) in tape‐stripped samples were analysed using an enzyme‐linked immunosorbent assay.Elastic fibres exhibited increased curvature and thickness with increased age, with fragmentation observed in women aged >60 years. Elastin scores, which reflect thinness and curvature, were negatively correlated with age, whereas they were positively correlated with R7 elasticity (recovery ability). In individuals aged 20–30 years, higher levels of inflammatory markers (HSP27 and Gal‐7) correlated with lower elastin scores; however, this trend was not observed in older participants.Elastic fibre deterioration worsened after 40 years of age, and this effect correlated with reduced skin recovery and increased wrinkles. In younger individuals, inflammatory markers affected elastic fibres. These findings can guide anti‐ageing strategies that focus on elastic fibre preservation and inflammation control. [ABSTRACT FROM AUTHOR]

The resistivity scaling of Cu electrical interconnects represents a critical challenge in Si CMOS technology. As interconnect dimensions reach below 10 nm, Cu resistivity increases significantly due to surface scattering. Topological materials have been considered for application in ultra-scaled interconnects (below 5 nm), due to their topologically protected surface states that have reduced electron scattering. Recent theoretical work on the topological chiral semimetal CoSi suggests that this material could offer lower resistivity than Cu at dimensions smaller than 10 nm. Here we investigate the scaling trend of textured and amorphous CoSi thin films, deposited by molecular beam epitaxy in a thickness range between 2 and 82.5 nm. Contrary to predictions of standard resistivity models, we report here a reduction in resistivity for thin amorphous CoSi films, which is instead consistent with surface-dominated transport. Moreover, magnetotransport measurements reveal significant enhancement of the magnetoresistance in scaled films, highlighting the complex transport mechanisms present in these highly disordered films at thicknesses of a few nanometers. [ABSTRACT FROM AUTHOR]

The gap in spectra of a physical system is fundamental in physics, while gap topology further restricts possible occurrent gaps of topological boundary states. The emergence of non-Hermiticity unveils a unique gap type known as the point gap, which forecasts the wavefunction localization, known as the non-Hermitian skin effect. Therefore, experimentally identifying the point gap in the complex frequency plane through a real operating frequency can become a tool for the systematic investigation of skin effects. Here, we utilize a Weyl phononic crystal to demonstrate that the point gap constituted by bulk and Fermi-arc surface states can be observed experimentally by a real-space field mapping technique. The identified point gaps forecast various skin effects and their evolutions. We further experimentally demonstrate the hinge skin effect in a parallelogram structure. Our work provides a feasible recipe to explore point gap topology experimentally in a variety of systems and certainly stimulates the research on skin effects in three-dimensional systems. Point gap is signature of non-Hermitian systems, but the experimental identification of nontrivial point gaps is elusive. Here, the authors use a Weyl phononic crystal to demonstrate that the point gap constituted by bulk and Fermi-arc surface states can be observed experimentally by a real-space field mapping technique and discover various skin effects and their evolutions. [ABSTRACT FROM AUTHOR]

To be able to carry out a high-quality analysis of the operation and design of elevator systems with a driving pulley, it is necessary to determine the size of the losses that occur in the drive mechanism and elevator guide rails. The paper defines an experimental procedure for determining the losses and the efficiency coefficient of elevator facilities depending on the relative load of the cabin in operational conditions. The experiment was carried out on a passenger elevator with a rated load of 320 kg and a lifting height of 28 m. An analysis of the resistance, i.e., the source of power losses in vertical lifting devices, was performed, the most significant of which occur and are especially pronounced in worm gear reducers and on the guiding system of the cabin and counterweight, where the type of guiding elements also has an influence. A particular problem is expressed due to the changing state of the contact surfaces (between the guide rails and the guide shoes) during exploitation and the eccentric loading of the cabin. Also, the paper analysed the obtained measurement results to determine the dependence of the efficiency coefficient of the facility concerning the relative load of the cabin. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to model the loading direction‐dependent behaviours of inherently anisotropic intact clay by means of the hypoplastic framework. The basic hypoplastic model for clays proposed by Mašín (2013) is enhanced by incorporating a predefined anisotropic asymptotic state boundary surface formulation which is based on an anisotropic variable by projecting the microstructure tensor onto the normal of the spatially mobilized plane. The capability of the proposed hypoplastic model is first illustrated by simulations of intact Wenzhou soft clay under drained torsional shear tests using the hollow cylinder apparatus. The model is then used to predict undrained shear results on San Francisco Bay mud. Comparisons between the predicted and measured results demonstrate that the proposed hypoplastic model is capable of modelling the combined effect of the principal stress direction and intermediate principal stress on the stress‐strain behaviour of natural soft clay with inherent anisotropy. This paper proposes an improved hypoplastic model for inherently anisotropic clays by incorporating a novel anisotropic asymptotic state boundary surface formulation. [ABSTRACT FROM AUTHOR]

To enable the timely adjustment of the control strategy of automobile active safety systems, enhance their capacity to adapt to complex working conditions, and improve driving safety, this paper introduces a new method for predicting road surface state information and recognizing road adhesion coefficients using an enhanced version of the MobileNet V3 model. On one hand, the Squeeze-and-Excitation (SE) is replaced by the Convolutional Block Attention Module (CBAM). It can enhance the extraction of features effectively by considering both spatial and channel dimensions. On the other hand, the cross-entropy loss function is replaced by the Bias Loss function. It can reduce the random prediction problem occurring in the optimization process to improve identification accuracy. Finally, the proposed method is evaluated in an experiment with a four-wheel-drive ROS robot platform. Results indicate that a classification precision of 95.53% is achieved, which is higher than existing road adhesion coefficient identification methods. [ABSTRACT FROM AUTHOR]

In observing the electrocatalytic current of nanoparticles (NPs) using single-entity electrochemistry (SEE), the surface state of the NPs significantly influences the SEE signal. This study investigates the influence of capping agents on the electrocatalytic properties of gold (Au) NPs using SEE. Two inner-sphere reactions, hydrazine oxidation and glucose oxidation, were chosen to explore the SEE characteristics of Au NPs based on the capping agent presence. The results revealed that "capping agent-free" Au NPs exhibited signal magnitudes and frequencies consistent with theoretical expectations, indicating superior stability and catalytic performance in electrolyte solutions. In contrast, citrate-capped Au NPs showed signals varying depending on the applied potential, with larger magnitudes and lower frequencies than expected, likely due to an aggregation of NPs. This study suggests that capping agents play a crucial role in the catalytic performance and stability of Au NPs in SEE. By demonstrating that minimizing capping agent presence can enhance effectiveness in SEE, it provides insights into the future applications of NPs, particularly highlighting their potential as nanocatalysts in energy conversion reactions and environmental applications. [ABSTRACT FROM AUTHOR]

Chocolate mass is a cocoa butter-based suspension, which mainly consists of sugar and cocoa particles dispersed in a continuous lipid phase. During chocolate manufacturing, sugar particles have to be ground to sizes below 25–30 µm. Such a fine grinding is carried out either by five roll refiners or by ball mills. Despite obtaining similar particle size distributions at the end, the grinding procedures result in different chocolate mass properties. The reasons for that are not fully understood, so far. Therefore, changes in particle sizes and surface properties of sucrose particles as well as their interactions with surrounding cocoa butter during the different grinding processes were investigated including atomic force microscopy techniques to characterize local surface states. It was found that especially the alteration of surfaces during continued grinding differed. In the case of roller grinding, surface states became more inhomogeneous and different surfaces states at microscopic level existed in parallel. More homogenous surfaces but with a higher degree of amorphous states were formed during grinding in the ball mill. Variations in macroscopic behavior of the suspension can be explained by the differences in interaction of particles with each other and with the surrounding lipid phase. [ABSTRACT FROM AUTHOR]

This paper presents a novel incremental sliding mode control scheme to address the attitude-tracking issue in both the helicopter and airplane modes of an electric vertical takeoff and landing vehicle, guaranteeing the stabilization of the attitude-tracking error within a predefined time. Firstly, an incremental model of the vehicle's attitude control system with external disturbances is established. The high-order terms of the incremental model and instantaneous perturbations are retained as lumped terms rather than directly discarding them to ensure the accuracy of the incremental model. Then, a novel nonsingular sliding surface is developed. Once the ideal sliding motion is established, the states on the sliding surface will converge to the equilibrium point within a predefined time. Furthermore, a predefined-time incremental sliding mode controller is developed by using sliding mode control and incremental control techniques. It effectively reduces the reliance on the model information and attenuates the effects of external disturbances. The predefined-time stability of the entire controlled system is rigorously proven using Lyapunov theory. Finally, numerical simulation examples verify the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

In this study, fusiform bismuth (Bi) was synthesized, and its photocatalytic performance, degradation mechanism, and pathways for removing rhodamine B (RhB) at different pH levels were investigated. Additionally, the morphologies, structural characteristics, surface electronic states, optical properties, active species, and potential degradation pathways of RhB over the fusiform Bi were analyzed. The comparison of the results before and after RhB degradation using the fusiform Bi revealed the formation of a Bi/BiOCl heterojunction photocatalyst. At pH 2.0, 3.0, 5.0, 7.0, and 9.0, the heterojunction exhibited excellent photocatalytic activity, with RhB removal efficiencies of ~97%, 96.7%, 72.6%, 53.5%, and 27.6%, respectively. Moreover, total organic carbon and chemical oxygen demand analyses were performed to evaluate the mineralization rates of RhB with the fusiform Bi at pH 3.0 and 7.0. Furthermore, the effects of catalyst content, initial RhB concentration, light source distance, inorganic anions, and reactant temperature on the photocatalytic performance of the fusiform Bi were investigated. Additionally, the types of active species and potential photocatalytic mechanisms for RhB degradation over the fusiform Bi at different pH levels (3.0 and 7.0) were elucidated. The appropriate degradation pathways were identified via liquid chromatography–mass spectrometry at pH 3.0 and 7.0. [ABSTRACT FROM AUTHOR]

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This study examines a metal–semiconductor structure with an organic perylene interlayer by measuring capacitance (C) and conductance (G/w) versus voltage under various lighting conditions and illumination levels (dark and 50–250 mW cm−2) in a wide range of voltage (±5 V). The increase in illumination results in an increase in capacitance and conductance values in the depletion and accumulation regions due to surface-state illumination (Nss). The barrier height ( Φ B ) decreased from 1.617 eV (in the dark) to 0.543 eV (under 250 mW cm−2). The C–V plot demonstrates peak behavior before going negative at the accumulation region. As the illumination intensity increases, the peak magnitude also increases, and concurrently, its position shifts towards the densely accumulated region due to the illumination-induced changes in surface states (Nss) and the subsequent reordering/restructuring of these states. The lowest value of capacitance corresponds to the highest value of conductance, and the negative value of C decreases as illumination increases. The Hill–Coleman and Nicollian–Brews methods were used to obtain the voltage/illumination-dependent profile of Nss and Rs, respectively. The relaxation mechanism of the SBD was also explained using electric modulus formalisms. The slope of ln(σAC)–ln(P) plot changed from 0.474 and 0.824 and so Au/C20H12/n-Si SBD can be used in photonic applications. [ABSTRACT FROM AUTHOR]

Here, by using angle-resolved photoemission spectroscopy, we showed that Bi2−xCrxSe3 single crystals have a distinctly well-defined band structure with a large bulk band gap and undistorted topological surface states. These spectral features are unlike their thin film forms in which a large nonmagnetic gap with a distorted band structure was reported. We further provide laser-based high resolution photoemission data which reveal a Dirac point gap even in the pristine sample. The gap becomes more pronounced with Cr doping into the bulk of Bi2Se3. These observations show that the Dirac point can be modified by the magnetic impurities as well as the light source. [ABSTRACT FROM AUTHOR]

High‐efficiency quantum dot sensitized solar cells (QDSSCs) can be received by increasing quantum dot (QD) loading and mitigating QD surface trap states. Herein, the surface state of CuInS2 QDs is optimized through an I−/MPA dual‐ligands passivation strategy. The steric hindrance and electrostatic repulsion between QDs can be effectively reduced, thereby enabling an increased QD loading capacity. Meanwhile, the I−/MPA dual‐ligands passivation strategy can further lower the surface trap density, leading to substantially enhanced charge transfer efficiency of the solar cells. Interestingly, various iodized salts, including TBAI, MAI, and KI, are proved to possess comparable property, underscoring the versatility and broad applicability of this I−/MPA dual‐ligands passivation strategy. Eventually, CuInS2 QDSSCs based on the NH4I/MPA dual‐ligands exhibit a noteworthy enhancement in photovoltaic conversion efficiency, surpassing the benchmark of 5.71 % to reach 7.03 %. [ABSTRACT FROM AUTHOR]

Gate-voltage dependent quantum oscillations in topological insulator Sn0.02Bi1.08Sb0.9Te2S (Sn-BSTS) are analyzed on the basis of the Lifshitz−Kosevich theory. The angular dependence of the quantum oscillations and Landau-level fan diagram analysis show that the quantum oscillations originate from topological surface states with the Berry phase of π. Gate-voltage control allows precise control of the Fermi energy, and a very weak energy dependence of the relaxation time τ of the topological surface states is revealed. By a simple algebraic argument using the linear response theory, it is shown that the weak energy dependence of τ validates the constant relaxation time approximation [ τ E , T = τ 0 ] in the calculation of the Seebeck coefficient S and z T e l = σ S 2 T / κ e l . [ABSTRACT FROM AUTHOR]

The properties of cubic boron arsenide (c-BAs) (100), (110), and (111) surfaces are investigated by performing first-principles calculations using the slab and Green's function surface models with different terminals. The (111) surface with As-termination is found to be the most stable structure among the studied surfaces, with its lowest surface energy (1.70–1.92 J m−2) and largest surface density (20.24 nm−2). The electronic affinity of these surfaces lie in the range 4.62–6.17 eV, which is higher than that of common semiconductor materials, such as silicon (4.05 eV) and germanium (4.13 eV), implying that the electrons at the bottom of the conduction band require more energy to escape. The surface states of the structures with As-termination in the surface band structures are generally more numerous and extended than those with B-termination. The absorption peak of the bulk c-BAs is located in the ultraviolet region, and the light absorption ranges of the surfaces are significantly extended compared with the bulk c-BAs, due to the surface states inside the bandgap. [ABSTRACT FROM AUTHOR]

Helicobacter pylori (H. pylori) is a common pathogen with a high prevalence of infection in human populations. The diagnosis of H. pylori infection is critical for its treatment, eradication, and prognosis. Biosensors have been demonstrated to be powerful for the rapid onsite detection of pathogens, particularly for point-of-care test (POCT) scenarios. In this work, we propose a novel optical biosensor, based on nanomaterial porous silicon (PSi) and photonic surface state Tamm Plasmon Polariton (TPP), for the detection of cytotoxin-associated antigen A (CagA) of H. pylori bacterium. We fabricated the PSi TPP biosensor, analyzed its optical characteristics, and demonstrated through experiments, with the sensing of the CagA antigen, that the TPP biosensor has a sensitivity of 100 pm/(ng/mL), a limit of detection of 0.05 ng/mL, and specificity in terms of positive-to-negative ratio that is greater than six. From these performance factors, it can be concluded that the TPP biosensor can serve as an effective tool for the diagnosis of H. pylori infection, either in analytical labs or in POCT applications. [ABSTRACT FROM AUTHOR]

In a precision machining environment, suspended particles in the air have a non-negligible effect on visual roughness measurement results. To address this issue, this paper analyzes the influence of particles on the visual roughness measurement from theoretical derivation and numerical simulation, respectively. Firstly, based on the Lambert-Beer and the light scattering principles, the propagation equation of incident light under the joint action of suspended particles and rough surfaces is derived. Then, a numerical simulation model is designed, and the theoretical equations are verified by simulation experiments. The influence of particle material, particle size (D), particle concentration (N), light wavelength (λ), and SiC surface roughness (Ra) on the average electric field magnitude of the energy-acquisition boundary are analysed based on the simulation experiments. The theoretical derivation shows that the average electric field magnitude of the energy-acquisition boundary is mainly influenced by particle state and rough surface state. The simulation experiment results show that both the particle parameters and the rough surface parameters are consistent with the theoretical derivation. As Ra increases, the effect of N on the measurement results decreases. The results reveal the influence mechanism of suspended particles on the visual roughness measurement results and provide a basis for improving visual roughness measurement accuracy. [ABSTRACT FROM AUTHOR]

The interface and dielectric environment of graphene transistors are of great importance to commercial circuit integrations. The tangling bond in oxide‐based dielectric severely lagged the carrier mobility while the 2D dielectric layer (for instance, hexagonal boron nitride) unavoidably hastened complicated condensed physics even at room temperature. Herein, multilayer black phosphorus (BP) a versatile and widely‐tunable dielectric candidate for manifesting graphene fermions is demonstrated. Because of hetero‐interfacial charge redistributions, a vertical electric double‐layer between the bottom BP layer and top graphene spontaneously forms with the central BP layer as a soft barrier. Under dual‐gate modulation, abnormal step‐like evolution of Dirac fermions and charge‐transfer quantum Hall effect arises while the intrinsic Dirac behavior of graphene is preserved, ascribing to the gate‐tunable charge redistributions of dielectric BP layer. Moreover, the electric double‐layer transistors apply equally well to bilayer graphene with similar Dirac behavior but an enhanced interfacial charge interference. The findings not only create a new avenue to manipulate the fermions by assembling graphene with narrow‐gapped 2D layered materials but also promote electric double‐layer transistors as a new build block to design multifunctional devices. [ABSTRACT FROM AUTHOR]

Tin dioxide (SnO 2) is widely utilized for the cost-effective electron transport layer (ETL) in perovskite solar cells (PSCs) owing to its excellent optoelectronic properties. However, the surface defect states present in SnO 2 ETL prepared by conventional solution methods seriously hinder the further improvement of device photovoltaic performance. It is urgently essential to develop a facile strategy to effectively minimize the adverse effects of SnO 2 ETL on PSCs. Herein, a phosphorus hetero-phenanthrene flame retardant, DOPO, is introduced as a multifunctional surface modifier to improve the interfacial properties between SnO 2 ETL and perovskite. Through systematic characterization analysis, the P O group in DOPO not only passivates the defective states on the surface of SnO 2 ETL, but also provides chemical chelation sites for the uncoordinated Pb2+ ions in the upper perovskite structure to improve the film crystalline quality. Eventually, the photoelectric conversion efficiency (PCE) of the optimized device is improved from an initial 19.74 %–22.57 %, along with significantly improved device stability. This work provides an important reference for the development of new multifunctional interface modification materials required for SnO 2 -based planar PSCs with excellent properties. [ABSTRACT FROM AUTHOR]

Bi2Se3 has a unique surface state and excellent electron transport performance, but because of its narrow band gap, Bi2Se3‐based photodetectors are difficult to achieve high response to ultraviolet (UV) light. In this paper, the TiO2/Bi2Se3 heterostructure was constructed by spin‐coating TiO2 on Bi2Se3 film, and TiO2/Bi2Se3 heterostructure‐based photoelectrochemical (PEC) photodetector was constructed, and a series of measurements were carried out. The measure results showed that the photoresponse performance of TiO2/Bi2Se3 heterostructure‐based photodetector was improved in the visible region, and the performance in the UV was further improved. This is because the type ii band alignment between TiO2 and Bi2Se3 is beneficial for the effective separation and transfer of photogenerated electron‐hole pairs, reducing recombination losses and enhancing the overall photoresponse. In addition, under the action of the built‐in electric field formed by the heterostructure, the photogenerated electrons and holes are easier to separate, which reduces the recombination probability of the photogenerated electron‐hole pair and improves the photoelectric conversion efficiency. In the UV, TiO2/Bi2Se3 heterostructure can make more efficient use of the light absorption characteristics of TiO2 and absorb more photons, resulting in a larger photocurrent. These results indicate that TiO2/Bi2Se3 heterostructure‐based photodetector has great application potential in the UV. [ABSTRACT FROM AUTHOR]

Constrained by a limited understanding of the structure and luminescence mechanisms of carbon dots (CDs), achieving precise enhancement of their photoluminescence (PL) performance without altering the emission wavelength and color remains a challenge. In this work, a deuterated CD is first achieved by simply replacing the reaction solvent from H2O to D2O. The substitution of D atoms for H atoms is not limited on the surface but also within the internal structure of CDs. Deuteration affects the formation of the π‐conjugated network structure by altering the content of sp2 carbon and sp3 carbon, ultimately inducing a reconstruction for energy level structure of CDs. Both the intrinsic state and surface state emission, including quantum yield, emission intensity and lifetime, are significantly enhanced after deuteration. It benefits from the reduction in non‐radiative transitions, since the lowered vibrational frequencies of D atoms and optimized local energy level distribution in CDs structure. The deuterated CDs are applied in the fabrication of white‐light‐emitting diodes to show their application potential. This work provides a highly versatile route for improving and controlling photoluminescence performance of CDs and has opportunities to guide the development of CDs for practical applications. [ABSTRACT FROM AUTHOR]

This study demonstrates effective manipulation of exciton spin dynamics in a prototypical chiral inorganic nanosystem, i.e., cadmium selenide (CdSe) nanosheets capped with chiral cysteine ligands in aqueous solution, via facile pH‐regulation that can directly modify the electronic coupling between CdSe and cysteine's thiol group through Cd─S bonding. The comparative scrutiny by using transient circular dichroism spectroscopy enables to decipher the pertinent mechanisms behind the pH‐regulated spin‐flip dynamics. The hole‐trapping interaction between the valence‐band heavy‐hole spin state of CdSe and the cysteine‐induced "extrinsic" surface state is found to play a dominant role in prolonging the hole spin relaxation lifetime (by more than threefold). This study also demonstrates a relevant application in modulating the sensitivity of circularly polarized light detection. This work sets a paradigm for harnessing the elusive interactions in chiral inorganic nanosystems to achieve desired spin‐polarization regulation, refreshing the fundamental understanding about the mechanisms of spin dynamics involved therein. [ABSTRACT FROM AUTHOR]

The broken inversion symmetry at the ferromagnet (FM)/heavy‐metal (HM) interface leads to spin‐dependent degeneracy of the energy band, forming spin‐polarized surface states. As a result, the interface serves as an effective medium for converting spin accumulation into 2D charge current through the inverse Rashba–Edelstein effect. Exploring and assessing this spin‐to‐charge conversion (SCC) phenomenon at the FM/HM interface can offer a promising avenue to surpass the presumed limits of SCC in bulk HM layers. Spintronic heterostructures are utilized as a platform to measure the SCC experienced by photoexcited spin currents. Therefore, FM/HM heterostructures emitting terahertz electric field upon illumination by femtosecond laser pulses enable quantitative measure of the ultrafast SCC process. This results demonstrate a robust interfacial spin‐to‐charge conversion (iSCC) within a synthetic antiferromagnetic heterostructure, specifically for the NiFe/Ru/NiFe configuration, by isolating the SCC contribution originating from the interface and the bulk heavy‐metal (HM). Through the measurements of the emitted terahertz pulse, the iSCC at the NiFe/Ru interface is identified to be ≈27% of the strength as compared to SCC from the highest spin‐Hall conducting heavy‐metal, Pt. The results thus highlight the significance of interfacial engineering as a promising pathway for achieving efficient ultrafast spintronic devices. [ABSTRACT FROM AUTHOR]

For the first time pilot castings of an aluminum alloy into a patented mold with an evaporative-condensation cooling system are carried out with extraction of the resulting cylindrical billet obtained with a diameter of 62 mm. It is shown that the flow rate of cooling water to a mold may be reduced by a factor of 2–3 by increasing the temperature of the water leaving the condenser to t = 60–80 °C. Adjustments are made to the design calculation of wall temperatures, taking into account preliminary heating of the crystallizer and experimental values of temperatures. The state of the surface of the workpieces obtained is analyzed in two pouring modes. Calculation and comparison of heat supplied to and removed from the mold, and thickness of a billet skin are performed. [ABSTRACT FROM AUTHOR]

Until recently, it was attempted to explain the flame propagation without considering the chain nature of combustion, but the contradictions between theory and experiments failed to be explained. The difference in the roles of reaction chains and self-heating was not considered, as well as the role of heterogeneous chain termination. These issues are addressed in this chapter. Greater uncertainty in the quantitative interpretation of gas combustion is due to the limited information on heterogeneous reactions of active particles and the nonstationary state of the surface. Under these limitations, the propagation of flame of the 4H2 + O2 mixture was simulated. To reduce the role of the nonstationary state of the surface, conditions for the limiting role of diffusion of H atoms to the walls were chosen. A method for solving differential equations and conditions for replacing the Laplace operator with an averaging rate constant for the chemisorption of atomic hydrogen are described. The flat flame approximation is used. The flame characteristics for their comparison with the results of experiments conducted with the participation of the author were obtained. Experimental results showing the strong dependence of all characteristics of flame propagation on the changing properties of the surface are presented. [ABSTRACT FROM AUTHOR]

X-ray diffraction (XRD) and the finite element technique (FET) to measure the residual stresses (RS) inside Al1060 rods produced by forming operation at three different half extrusion angles (HEA = 20°, 40°, and 60°) were applied. The results of the experimental work and FET illustrate a good convergence in terms of the relationship between extrusion force and displacement with an error ratio reaching 15 %. The effect of HEA = 20° on extrusion force is the lowest compared to others. Moreover, the behavior of the obtained residual stresses from XRD and FET is in good agreement with the existence of some variation in their values. The profile of these stresses is in a tensile state near the rod surface and a compressive state near the axis at HEA = 20° and 40°. In contrast, compressive residual stresses are obtained close to the surface and center of the extruded rod at HEA = 60°. [ABSTRACT FROM AUTHOR]

Heterogeneity in the fluorescence of carbon dots (CDs) has been hard to figure out so far. This could potentially be related to structural factors, size or intermediate fluorophores, especially when employing the bottom‐up synthesis. Herein, we unveil the origin of fluorescence and spectral heterogeneity of CDs using a simple dynamic method. This work reports the room light‐excited green fluorescence and dual‐emissive N‐doped CDs synthesized using a hydrothermal method. Studies were carried out considering the factors of fluorescence phenomena, such as excitation‐independent emission, fluorescent impurities, aggregation and solvation dynamics. The new steady‐state, Excitation‐resolved area‐normalized emission spectroscopy (ERANES) and ensemble measurements, including time‐resolved studies reveal that a heterogeneous environment exists in the ground state. Eventually, the results show the existence of core, edge and surface states in the CDs. Additionally, the fluorescence characteristics depend on the structural functionalization that occurs in both the intrinsic and extrinsic states of the CDs and it is proven that this does not violate the Kasha‐Vavilov rule. Although a highly purified material could still exhibit heterogeneity due to the ensemble emissive states and structural variations. Our results provide insights into the enduring debates about fluorescence and a deeper understanding of the structure‐ property relationship of CDs. [ABSTRACT FROM AUTHOR]

Surface reconstruction determines the fate of catalytic sites on the near-surface during the oxygen evolution reaction. However, deciphering the conversion mechanism of various intermediate-states during surface reconstruction remains a challenge. Herein, we employed an optical imaging technique to draw the landscape of dynamic surface reconstruction on individual Co3O4 nanoparticles. By regulating the surface states of Co3O4 nanoparticles, we explored dynamic growth of the CoOx(OH)y sublayer on single Co3O4 nanoparticles and directly identified the conversion between two dynamics. Rich oxygen vacancies induced more active sites on the surface and prolonged surface reconstruction, which enhanced electrochemical redox and oxygen evolution. These results were further verified by in situ electrochemical extinction spectroscopy of single Co3O4 nanoparticles. We elucidate the heterogeneous evolution of surface reconstruction on individual Co3O4 nanoparticles and present a unique perspective to understand the fate of catalytic species on the nanosurface, which is of enduring significance for investigating the heterogeneity of multielectron-transfer events. [ABSTRACT FROM AUTHOR]

Low‐energy visible‐light‐activated carbon dots (CDs)‐based afterglow materials are difficult to realize due to the inherent aromatic carbon with high‐energy absorption and the lack of effective regulation. Here, a new strategy for visible‐light‐activated CDs is proposed by combining dual‐confinement and surface‐ionization, which employs NaOH for additional confinement and surface ionization of CDs in a single boric acid (BA) matrix. The comparison experiments show that: i) shifting the excitation from UV‐light to vis‐light is realized by enhancing the low‐energy surface states n→π* transition of the CDs by surface ionization of NaOH. ii) CDs are additionally protected by a more stable Na─O ionic bond after NaOH confinement, resulting in a brighter afterglow. iii) the energy gap (ΔEST) between the lowest singlet and triplet states is gradually shortened as increasing NaOH content, facilitating intersystem crossing, prolonging the lifetime of triplet excitons and efficiency. Further, vis‐light‐excited colorful afterglow powders are fabricated based on Förster Resonant Energy Transfer by combining the fluorescent dye 5‐carboxytetramethylrhodamine. Finally, advanced white‐light‐activated time‐resolved anti‐counterfeiting and intelligent traffic flashing signs are realized. The work may shed new light on the design of low‐energy‐activated afterglow materials and broaden the application scenarios in the daily lives of human society. [ABSTRACT FROM AUTHOR]

The study of topological phases with unconventional bulk‐boundary correspondences and nontrivial real Chern number has garnered significant attention in the topological states of matter. Using the first‐principle calculations and theoretical analysis, a high‐throughput material screening of the 3D obstructed atomic insulators (OAIs) and 3D real Chern insulators (RCIs) based on the Samara Carbon Allotrope Database (SACADA) are performed. Results show that 422 out of 703 3D carbon allotropes are 3D OAIs with multiple bulk‐boundary correspondences, including 2D obstructed surface states (OSSs) and 1D hinge states, which are in 1D and 2Ds lower than the 3D bulk, respectively. The 2D OSSs in these OAIs can be modified when subjected to appropriate boundaries, which benefits the investigation of surface engineering and the development of efficient topological catalysts. These 422 OAIs, which have 2D and 1D boundary states, are excellent platforms for multi‐dimensional topological boundaries research. Remarkably, 138 of 422 OAIs are also 3D RCIs, which show a nontrivial real topology in the protection of spacetime inversion symmetry. This work not only provides a comprehensive list of 3D carbon‐based OAIs and RCIs, but also guides their application in various aspects based on multiple bulk‐boundary correspondences and real topological phases. [ABSTRACT FROM AUTHOR]

The Atmospheric InfraRed Sounder (AIRS) aboard Aqua provides essential long‐term data on vertical cloud fraction, particularly valuable in the Arctic region. This study offers a comprehensive assessment of Arctic vertical cloud fraction derived from AIRS through a comparison with independent ground‐ and space‐based radar and lidar observations. In comparison to the measurements at the North Slope Alaska site, results reveal a significant underestimation of low‐level cloud cover by AIRS, especially for near‐surface clouds, while mid‐ and high‐level cloud fractions show better consistency. In comparison to the satellite‐based product from 3S‐GEOPROF‐COMB, the accuracy varies across different underlying surfaces (land vs. sea) and seasons. AIRS shows significant positive biases in mid‐level cloud fraction over sea surfaces with sea ice concentration below 15%, indicating potential limitations in the cloud retrieval algorithm in regions with large sea ice variations. The issue of low‐level clouds identification is primarily caused by the limited penetrating capability of infrared hyperspectral sensing and the accuracy of preceding surface and atmospheric state products, which diminish the accuracy of AIRS low‐level cloud fraction. Plain Language Summary: The Atmospheric InfraRed Sounder (AIRS) instrument on the Aqua satellite provides important information on vertical cloud fraction in the Arctic. This research compared the AIRS cloud cover data with observations from ground‐based and space‐based radar and lidar. Findings are that AIRS underestimates low‐level clouds, especially near the surface, but is more accurate for mid‐ and high‐level clouds. The accuracy also varies over land and sea surfaces, as well as throughout different seasons. In regions with significant sea ice variations, AIRS overestimates clouds at mid‐levels. The study suggests that the ability to accurately detect low‐level clouds from AIRS is limited by the capability of infrared hyperspectral sensing to penetrate the atmosphere. Key Points: Initial evaluation of AIRS vertical cloud fraction product over the Arctic is presented using ground‐ and space‐based radar‐lidar observationsAIRS underestimates low‐level clouds, especially near the surface, more accurately reflects mid‐ and high‐level cloud fractionsAIRS mid‐level cloud fraction demonstrates significant positive biases over regions with sea ice concentration below 15% [ABSTRACT FROM AUTHOR]

Enhancing the electronic and ionic conductivity of Li 4 Ti 5 O 12 electrode materials, as well as suppressing the interface reaction between Ti4+ on the surface of Li 4 Ti 5 O 12 and the electrolyte, is one of the key factors in preparing high-power and long-life Li 4 Ti 5 O 12 lithium-ion batteries. To tackle these challenges, fluorine ions with strong electronegativity was chosen as dopants to engineer fluorine-doped Li 4 Ti 5 O 12 electrode materials. Fluorine ion doping changes the surface state of Li 4 Ti 5 O 12 , increases the interface compatibility, suppresses the reactivity between Li 4 Ti 5 O 12 and the electrolyte, and forms a uniform SEI film during cycling. Moreover, fluorine ion doping induces the generation of oxygen vacancies and improves the crystallinity of Li 4 Ti 5 O 12 , thereby fostering improved electronic and ionic transport kinetics. The above appealing features enables the prepared fluorine-doped Li 4 Ti 5 O 12 material demonstrates exceptional high-rate performance, delivering specific capacities of 175 mAh·g−1/0.5C, 159 mAh·g−1/10C, and 138 mAh·g−1/50C. In essence, the fluoride ion doping strategy holds profound implications for enhancing electrode interface characteristics, transport kinetics, and the fabrication of high-power lithium-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Owing to the outstanding properties provided by nontrivial band topology, topological phases of matter are considered as a promising platform towards low-dissipation electronics, efficient spin-charge conversion, and topological quantum computation. Achieving ferroelectricity in topological materials enables the non-volatile control of the quantum states, which could greatly facilitate topological electronic research. However, ferroelectricity is generally incompatible with systems featuring metallicity due to the screening effect of free carriers. In this study, we report the observation of memristive switching based on the ferroelectric surface state of a topological semimetal (TaSe 4) 2 I. We find that the surface state of (TaSe 4) 2 I presents out-of-plane ferroelectric polarization due to surface reconstruction. With the combination of ferroelectric surface and charge-density-wave-gapped bulk states, an electric-switchable barrier height can be achieved in (TaSe 4) 2 I-metal contact. By employing a multi-terminal-grounding design, we manage to construct a prototype ferroelectric memristor based on (TaSe 4) 2 I with on/off ratio up to 103, endurance over 103 cycles, and good retention characteristics. The origin of the ferroelectric surface state is further investigated by first-principles calculations, which reveal an interplay between ferroelectricity and band topology. The emergence of ferroelectricity in (TaSe 4) 2 I not only demonstrates it as a rare but essential case of ferroelectric topological materials, but also opens new routes towards the implementation of topological materials in functional electronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] The Bloch band theory and Brillouin zone (BZ) that characterize wave-like behaviors in periodic mediums are two cornerstones of contemporary physics, ranging from condensed matter to topological physics. Recent theoretical breakthrough revealed that, under the projective symmetry algebra enforced by artificial gauge fields, the usual two-dimensional (2D) BZ (orientable Brillouin two-torus) can be fundamentally modified to a non-orientable Brillouin Klein bottle with radically distinct manifold topology. However, the physical consequence of artificial gauge fields on the more general three-dimensional (3D) BZ (orientable Brillouin three-torus) was so far missing. Here, we theoretically discovered and experimentally observed that the fundamental domain and topology of the usual 3D BZ can be reduced to a non-orientable Brillouin Klein space or an orientable Brillouin half-turn space in a 3D acoustic crystal with artificial gauge fields. We experimentally identify peculiar 3D momentum-space non-symmorphic screw rotation and glide reflection symmetries in the measured band structures. Moreover, we experimentally demonstrate a novel stacked weak Klein bottle insulator featuring a nonzero Z 2 topological invariant and self-collimated topological surface states at two opposite surfaces related by a nonlocal twist, radically distinct from all previous 3D topological insulators. Our discovery not only fundamentally modifies the fundamental domain and topology of 3D BZ, but also opens the door towards a wealth of previously overlooked momentum-space multidimensional manifold topologies and novel gauge-symmetry-enriched topological physics and robust acoustic wave manipulations beyond the existing paradigms. [ABSTRACT FROM AUTHOR]