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Besides numerous experimental reports revealing the characteristic dependence of depression on liquid surfaces induced by impinging plasma beams, and despite its scientific and practical importance, the physical mechanism responsible for this dependency has been missed. In this study, based on the border electrons' role, the water/plasma interfacial dynamics relevant to electrohydrodynamic instability (EHD) have been theoretically modeled, focusing on the characteristic dependence of the EHD growth rate driven by charge mobility mechanisms. The predictions of the growth rates dependent on water conductivity from theory agree well with our observations of faster plasma-filled underwater bubble explosions under lower conductivity conditions, indicating that the model contains the essence of the underlying physics of liquid surface deformation in the presence of plasma. [ABSTRACT FROM AUTHOR]

Use and performance criteria of photonic devices increase in various application areas such as information and communication, lighting, and photovoltaics. In many current and future photonic devices, surfaces of a semiconductor crystal are a weak part causing significant photo-electric losses and malfunctions in applications. These surface challenges, many of which arise from material defects at semiconductor surfaces, include signal attenuation in waveguides, light absorption in light emitting diodes, non-radiative recombination of carriers in solar cells, leakage (dark) current of photodiodes, and light reflection at solar cell interfaces for instance. To reduce harmful surface effects, the optical and electrical passivation of devices has been developed for several decades, especially with the methods of semiconductor technology. Because atomic scale control and knowledge of surface-related phenomena have become relevant to increase the performance of different devices, it might be useful to enhance the bridging of surface physics to photonics. Toward that target, we review some evolving research subjects with open questions and possible solutions, which hopefully provide example connecting points between photonic device passivation and surface physics. One question is related to the properties of the wet chemically cleaned semiconductor surfaces which are typically utilized in device manufacturing processes, but which appear to be different from crystalline surfaces studied in ultrahigh vacuum by physicists. In devices, a defective semiconductor surface often lies at an embedded interface formed by a thin metal or insulator film grown on the semiconductor crystal, which makes the measurements of its atomic and electronic structures difficult. To understand these interface properties, it is essential to combine quantum mechanical simulation methods. This review also covers metal-semiconductor interfaces which are included in most photonic devices to transmit electric carriers to the semiconductor structure. Low-resistive and passivated contacts with an ultrathin tunneling barrier are an emergent solution to control electrical losses in photonic devices. [ABSTRACT FROM AUTHOR]

Droplet impact dynamics is an interfacial phenomenon that is shown everywhere in nature and is the underlying of numerous technological applications including bio-printing, tissue engineering, pharmaceuticals, fight against COVID-19 pandemic, smart biomaterials, and flexible electronics. Over the last decade, expeditious advancement of novel functional interfacial surfaces, high-speed visualization, nanoscience, nanotechnology, machine learning, and computational power, as well as the connection of flow physics with interfacial science, have contributed to enhancing the understanding of relevant complex physical phenomena. Droplet, upon impacting onto substrates, can deposit, spread, bounce, and splash. Features of droplet impact physics and surface wettability necessitate elaborate solid–liquid interactions. Given the significance of droplet impact physics for healthcare and electronics, it is recommended for the scientific community to direct research studies to profound the understanding of such complex physics. Therefore, this Review initially focuses on liquid–solid interfacial science. Second, droplet impact physics on numerous solid surfaces was discussed. Substrates with various wettability and physical features were considered: hydrophilic, hydrophobic, superhydrophobic, smooth, rough, and flexible elastic surfaces. Furthermore, numerous advancements of droplet impact on solid surfaces related to advanced technologies and challenges including printed electronics, smart biomaterials, tissue engineering, machine learning, and COVID-19 pandemic were reviewed. Finally, this Review outlines future perspectives and research directions in complex droplet impact physics. [ABSTRACT FROM AUTHOR]

In fixed point theory, interpolation is acknowledged in numerous areas of research, for instance, earth sciences, metallurgy, surface physics, and so on because of its prospective applications in the estimation of signal sensation analysis. As a result, it is interesting to investigate the fixed point and fixed circle (disc) utilizing interpolative techniques via partial b‐metric spaces in which non‐trivial as well as real generalizations are feasible. We define some improved interpolative contractions to create an environment for the existence of a fixed point and fixed circle and solve a two‐point boundary value problem related to a differential equation of second order. The obtained conclusions are validated by providing illustrative examples. Determining the fixed point of a non‐self mapping, the uniqueness of the fixed point and fixed circle, and the study of fractal interpolants would also be a fascinating investigation in the time to come. [ABSTRACT FROM AUTHOR]

Pulsar electrodynamics could be relevant to the physics of stellar surface, which remains poorly understood for more than half a centenary and is difficult to probe due to the absence of direct and clear observational evidence. Nevertheless, highly sensitive telescopes (e.g., China's Five‐hundred‐meter Aperture Spherical radio Telescope, FAST) may play an essential role to solve the problem since the predicted surface condition would have quite different characteristics in some models of pulsar structure, especially after the establishment of the standard model of particle physics. For instance, small hills (or "zits") may exist on solid strangeon star surface with rigidity, preferential discharge, that is, gap sparking, may occur around the hills in the polar cap region. In this work, with the 110‐min polarization observation of PSR B0950+$$ + $$08 targeted by FAST, we report that the gap sparking is significantly non‐symmetrical to the meridian plane on which the rotational and magnetic axes lie. It is then speculated that this asymmetry could be the result of preferential sparking around zits which might rise randomly on pulsar surface. Some polarization features of both single pulses and the mean pulse, as well as the cross‐correlation function of different emission regions, have also been presented. [ABSTRACT FROM AUTHOR]

Piezoelectric nanobeams are important components in micro-nano electromechanical systems. They are often used as mechanical structures such as wireless sensors, biological probes and transistors. And their mechanical performance is a very important research topic. Based on the theory of surface elasticity and the "core–shell" model, post-buckling behavior of porous piezoelectric nanobeams is analyzed using the first-order shear deformation beam theory, where the surface effect is introduced by employing the surface energy model. The governing equations and boundary conditions of post-buckling of porous piezoelectric nanobeams under mechanical loading were derived by introducing the concept of median surface in physics and the principle of minimum potential energy. The influence of surface effect on post-buckling configuration, post-buckling path, amount of induced charge and critical load of porous piezoelectric nanobeams with different external constraints and porosities were discussed. The results show that considering surface effects, the effective elastic modulus and critical load of porous piezoelectric nanobeams will be increased, and the post-buckling configuration, post-buckling path and amount of induced charge will be reduced. Meanwhile, the mechanical properties of porous piezoelectric nanobeams can be effectively improved by appropriate pore distribution. These findings can be used as a theoretical basis for the accurate design and manufacture of micro-nano mechanical and electronic devices. [ABSTRACT FROM AUTHOR]

Horizontal convective rolls (HCR) are sub-mesoscale motions that influence the transport of heat, momentum, and pollutants within the boundary layer. In this work, a high-resolution (0.666 km) Weather Research and Forecasting (WRF) model is employed to simulate the structure of the HCRs over Kalpakkam along the southeast coast of India. The sensitivity of HCR simulation to model land surface physics is studied with two land surface models (LSM), (i) Noah and (ii) Noah multi-parameterization (NMP), for three selected days (15 April 2013, 07 May 2015, 28 March 2018) during summer synoptic conditions. On all three selected days, the boundary layer rolls formed over a period of about 2–3 h in the morning under moderate winds (4–5.0 m/s), moderate vertical wind shear (2.4–3.5 m/s) in the lower atmosphere, and slightly unstable conditions [gradient Richardson number (RiG) −4.5 to −5.0] in both simulations and observations, indicating that thermal instability is the chief mechanism in their development. Simulated mean surface meteorological parameters by NMP were found to be in better agreement with observations than Noah. Results suggest that the LSMs mainly affected the simulated turbulent roll structure in terms of updraft cores and their horizontal and vertical extent by variation in simulated surface energy fluxes, boundary layer structure, wind shear, and stability. The structure of simulated HCRs is better represented by NMP due to the improvements in the flux distribution and surface properties. Simulations using the FLEXPART dispersion model for a hypothetical case of tracer release indicated an uneven spatial concentration pattern due to upward and downward motions in the region of HCRs. The stronger winds and stronger flow convergence in Noah and higher heat flux and more unstable conditions in NMP led to differences in the simulated tracer concentrations in the two cases. [ABSTRACT FROM AUTHOR]

Grain boundary grooving significantly affects the grain growth behavior in a polycrystalline thin film with columnar grain structure by partial or complete pinning of moving grain boundaries. Theoretically, it can be shown that the stagnation of grain growth can occur for certain combinations of grain size and film thickness, for which grain boundaries cannot escape from the groove root. However, in real systems, grooves attached with the grain boundaries can migrate along with the moving grain boundaries. The possibility for stagnation arises when a groove behaves like a notch fixed at the surface. Such a condition can arise if the surface diffusivity is sufficiently reduced after stable groove formation using surface treatment. In the present study, grain growth in a solid-state thin film is investigated using a three-dimensional phase-field method that allows grains of a solid phase to be in equilibrium with a vapor phase at a constant temperature. The model captures the essential physics of surface diffusion-controlled thermal grooving and its interaction with a moving grain boundary. From the phase-field simulations, three possible interactions between the grain boundary and the groove are identified: stagnation of grain boundary, grain boundary-groove detachment, and coupled movement of the groove and the grain boundary. [ABSTRACT FROM AUTHOR]

The phenomenon of a water droplet impact on a free surface is studied to understand the physics of free surface bubble entrainment. Particle image velocimetry (PIV) and high-speed image system are used to analyse the flow structure evolutions in the droplet impact cavity period and bubble entrainment cavity period, respectively. The photographic results show that the entrapped surface of the impact cavity remains intact and continuous, and individual bubble entrainment occurs during the secondary entrainment cavity evolution. The instantaneous distributions of velocity fields in the longitudinal and lateral directions are uniform and independent of the approaching impact velocity. For the entrainment cavity evolution, the transverse diffusion intensity is higher than that for the impact cavity period. An individual bubble forms during the transverse velocity penetration across the droplet impact area. Consequently, for the droplet impact on a water surface, the present study implies the presence of a mechanism by which the interior flow field plays a key role in the bubble entrainment. [ABSTRACT FROM AUTHOR]

We study the growth of entanglement entropy in a doubly holographic model of gravity for a spherical AdS black hole. Compared to previous work, which was limited to the case of planar black holes, this introduces an extra scale to the problem. This allows us to analyze the interplay between the reorganization of entanglement entropy due to island formation and the onset of the Hawking-Page phase transition and to find the appearance of a new critical black hole radius unrelated to the thermodynamics. We also find that the geometry of the Ryu-Takayanagi surface capturing the physics of islands exhibits drastically different behavior than in the planar case. [ABSTRACT FROM AUTHOR]

We explore stochastic–fractional Drinfel'd–Sokolov–Wilson (SFDSW) equations for some wave solutions such as the cross-kink rational wave solution, periodic cross-rational wave solution and homoclinic breather wave solution. We also examine some M-shaped solutions such as the M-shaped rational solution, M-shaped rational solution with one and two kink waves. We also derive the M-shaped interaction with rogue and kink waves and the M-shaped interaction with periodic and kink waves. This model is used in mathematical physics, surface physics, plasma physics, population dynamics and applied sciences. Moreover, we also show our results graphically in different dimensions. We obtain these solutions under some constraint conditions. [ABSTRACT FROM AUTHOR]

To improve the ensemble prediction system of the tropical regional atmosphere model for the South China Sea (TREPS) in predicting landfalling tropical cyclones (TCs), the impacts of three new implementing strategies for surface and model physics perturbations in TREPS were evaluated for 19 TCs making landfall in China during 2014–16. For sea surface temperature (SST) perturbations, spatially uncorrelated random perturbations were replaced with spatially correlated ones. The multiplier f, which is used to form perturbed tendency in the Stochastically Perturbed Parameterization Tendency (SPPT) scheme, was inflated in regions with evident convective activity (f-inflated SPPT). Lastly, the Stochastically Perturbed Parameterization (SPP) scheme with 14 perturbed parameters selected from the planetary boundary layer, surface layer, microphysics, and cumulus convection parameterizations was added. Overall, all these methods improved forecasts more significantly for non-intensifying than intensifying TCs. Compared with f-inflated SPPT, the spatially correlated SST perturbations generally showed comparable performance but were more (less) skillful for intensifying (non-intensifying) TCs. The advantages of the spatially correlated SST perturbations and f-inflated SPPT were mainly present in the deterministic guidance for both TC track and wind and in the probabilistic guidance for reliability of wind. For intensifying TCs, adding SPP led to mixed impacts with significant improvements in probability-matched mean of modest winds and in probabilistic forecasts of rainfall; while for non-intensifying TCs, adding SPP frequently led to positive impacts on the deterministic guidance for track, intensity, strong winds, and moderate rainfall and on the probabilistic guidance for wind and discrimination of rainfall. [ABSTRACT FROM AUTHOR]

Fractional–stochastic Drinfel'd–Sokolov–Wilson equations (FSDSWEs) forced by multiplicative Brownian motion are assumed. This equation is employed in mathematical physics, plasma physics, surface physics, applied sciences, and population dynamics. The (G ′ / G) -expansion method is utilized to find rational, hyperbolic, and trigonometric stochastic solutions for FSDSWEs. Because of the priority of FSDSWEs, the derived solutions are more useful and effective in understanding various important physical phenomena. Furthermore, we used the MATLAB package to create 3D graphs for specific solutions in order to investigate the effect of fractional-order and Brownian motions on the solutions of FSDSWEs. [ABSTRACT FROM AUTHOR]

The article discusses the results of a study which synthesized a trilayer-type van der Waals heterostructure of manganese telluride/bismuth telluride/Iron (Tellurium, Selenium), which combined s-wave superconductivity, thickness-dependent magnetism and strong spin-orbital coupling. Topics covered include growth and scanning tunneling microscopy (STM) characterization of the heterostructure, the spatial distributions of superconducting states and STM measurement.

Using 3D sonic crystals as acoustic higher‐order topological insulators (HOTIs), 2D surface states described by spin‐1 Dirac equations at the interfaces between the two sonic crystals with distinct topology but the same crystalline symmetry are discovered. It is found that the Dirac mass can be tuned by the geometry of the two sonic crystals. The sign reversal of the Dirac mass reveals a surface topological transition where the surface states exhibit zero refractive index behavior. When the surface states are gapped, 1D hinge states emerge due to the topology of the gapped surface states. The zero refractive index behavior and the emergent topological hinge states are confirmed experimentally. This study reveals a multidimensional Wannier orbital control that leads to extraordinary properties of surface states and unveils an interesting topological mechanism for the control of surface waves. [ABSTRACT FROM AUTHOR]

• A formulated correlation between vibration characteristics and surface topography. • Time-varying vibration and texture features along the cutting path are extracted. • An interpretation of the mechanism behind machining chatter mode shift phenomenon. • A hybrid physics and data-driven method for the surface topography reconstruction. Machining thin-walled cylindrical workpieces is frequently subjected to vibration due to their low rigidity, resulting in complicated surface topography. This paper investigates the vibration characteristics of thin-walled cylinder turning as well as its effect on the machined surface topography comprehensively by means of numerical simulations and experimental measurements. It is seen that the circumferential shell mode of vibration exhibits higher sensitivity to the variation of the wall thickness than the axial beam mode. The features of the vibration characteristics as well as the machined surface textures of thin-walled workpieces are shifting in a cutting pass. The underlying physical mechanism behind this phenomenon was interpreted. By extracting the critical vibration frequency and surface waviness measurement along the cutting path, a hybrid physics and data-driven surface topography was reconstructed, which showed consistency with the real surface topography. The formulated correlation between the vibration characteristics and the surface topography contributes to a holistic understanding of dynamic behaviors of thin-walled cylinder machining, and a tool that utilizes vibration to produce functional microstructures on cylindrical surfaces. [ABSTRACT FROM AUTHOR]

This paper proposes a method for simulating liquids in large bodies of water by coupling together a water surface wave simulator with a 3D Navier‐Stokes simulator. The surface wave simulation uses the equivalent sources method (ESM) to efficiently animate large bodies of water with precisely controllable wave propagation behavior. The 3D liquid simulator animates complex non‐linear fluid behaviors like splashes and breaking waves using off‐the‐shelf simulators using FLIP or the level set method with semi‐Lagrangian advection. We combine the two approaches by using the 3D solver to animate localized non‐linear behaviors, and the 2D wave solver to animate larger regions with linear surface physics. We use the surface motion from the 3D solver as boundary conditions for 2D surface wave simulator, and we use the velocity and surface heights from the 2D surface wave simulator as boundary conditions for the 3D fluid simulation. We also introduce a novel technique for removing visual artifacts caused by numerical errors in 3D fluid solvers: we use experimental data to estimate the artificial dispersion caused by the 3D solver and we then carefully tune the wave speeds of the 2D solver to match it, effectively eliminating any differences in wave behavior across the boundary. To the best of our knowledge, this is the first time such a empirically driven error compensation approach has been used to remove coupling errors from a physics simulator. Our coupled simulation approach leverages the strengths of each simulation technique, animating large environments with seamless transitions between 2D and 3D physics. [ABSTRACT FROM AUTHOR]

Molecular level interactions that take place at the interface of different materials determine their local electrical, chemical, and mechanical properties. In the case of solid interfaces, this information has traditionally been obtained with experimental techniques that require ultra-high vacuum conditions. However, these methods are not suitable for studying surface chemistry of aqueous interfaces. Recently, an approach emerged for probing such interfaces using interfacial water as a contrast agent. This approach is based on second harmonic generation from water molecules next to a charged interface and can be utilized in both scattering and microscopy geometries. In this Perspective, we explain this approach in more detail and provide examples and comparisons for a diverse set of applications: colloid science and solid state physics, illustrated by silica–water surface chemistry, and biophysics, illustrated by membrane–water–ion channel interactions. Those two diverse applications show that by following the structure of interfacial water, it is possible to extract and quantify important chemical parameters such as surface potential values, structure of the electric double layer, and local dissociation constants that are useful in many different contexts. [ABSTRACT FROM AUTHOR]

Shoe outsole design strongly influences slip and fall risk. Certain tread features that can be readily measured have been shown to predict friction performance. This research aimed to replicate those findings and quantify their ability to predict slipping. Participants (n = 34) were exposed to a low friction oil-coated floor surface, while wearing slip-resistant shoes. The coefficient of friction (COF) of each shoe were predicted based on tread surface area, the presence of a bevel, and hardness. The COF was measured, and the slip outcome was determined. Predicted and measured COF were correlated, and measured COF was a sensitive predictor of slip outcome. The relationship of predicted COF on slip outcome was weaker than anticipated and was not statistically significant. This study partially confirmed the ability of previous regression equations to predict COF. However, the effect size was weaker than previously reported and predicted COF was not sensitive for predicting slips. • Validity of a coefficient of friction (COF) regression model was tested. • Slip outcomes, predicted COF, and measured COF was assessed for 34 shoes. • Weak relationships were reported between predicted COF and slip outcomes. • Predicted COF was correlated with measured COF, which correlated with slipping. • The study provided mixed prospective validation evidence for the model. [ABSTRACT FROM AUTHOR]

Recent work has highlighted roles for thermodynamic phase behavior in diverse cellular processes. Proteins and nucleic acids can phase separate into three-dimensional liquid droplets in the cytoplasm and nucleus and the plasma membrane of animal cells appears tuned close to a two-dimensional liquid–liquid critical point. In some examples, cytoplasmic proteins aggregate at plasma membrane domains, forming structures such as the postsynaptic density and diverse signaling clusters. Here we examine the physics of these surface densities, employing minimal simulations of polymers prone to phase separation coupled to an Ising membrane surface in conjunction with a complementary Landau theory. We argue that these surface densities are a phase reminiscent of prewetting, in which a molecularly thin three-dimensional liquid forms on a usually solid surface. However, in surface densities the solid surface is replaced by a membrane with an independent propensity to phase separate. We show that proximity to criticality in the membrane dramatically increases the parameter regime in which a prewetting-like transition occurs, leading to a broad region where coexisting surface phases can form even when a bulk phase is unstable. Our simulations naturally exhibit three-surface phase coexistence even though both the membrane and the polymer bulk only display two-phase coexistence on their own. We argue that the physics of these surface densities may be shared with diverse functional structures seen in eukaryotic cells. [ABSTRACT FROM AUTHOR]

Summary: Over the last few years, fractal structure has been used in several engineering fields such as surface physics, telecommunication, fluid mechanics, and so forth. In telecommunication, often there is a demand for miniaturized patch antennas with fractal structures because it is capable of handling very high frequencies with its diminutive structure. The space filling capability of the fractal structures is used to effectively distribute the surface current all over the radiating material. Fractal structures have a better size reduction capability which aids a miniaturized antenna design. This article provides a generalized and detailed survey on fractal structures in a Euclidean space using iterated function system (IFS) in patch antennas. There are various techniques to design a fractal structure, namely, IFSs, escape‐time fractals, strange attractors, L‐systems, random fractals, and so forth. IFSs are widely used technique to construct a finite set of construction mapping on a complete metric space. The fractal geometries designed using the technique are Sierpinski carpet and gasket, Koch snowflake, deterministic tree/binary tree, Gosper island, Minkowski island, Cantor set, T‐square, and some space filling fractals. This paper deals with the above given fractal structures with their design expressions and shapes in recent developments and applications mentioned. The fractal geometries are used in MIMO antennas to abridge the mutually coupled radiators and improve the gain and efficiency of the antenna. This paper also analyzes the effects of fractal structures on MIMO antennas and discusses the ascendancy fractal structures by cross‐referencing the significant antenna parameters. [ABSTRACT FROM AUTHOR]

The introduction of engineered resonance phenomena on surfaces has opened a new frontier in surface science and technology. Pillared phononic crystals, metamaterials, and metasurfaces are an emerging class of artificial structured media, featuring surfaces that consist of pillars—or branching substructures—standing on a plate or a substrate. A pillared phononic crystal exhibits Bragg band gaps, while a pillared metamaterial may feature both Bragg band gaps and local resonance hybridization band gaps. These two band-gap phenomena, along with other unique wave dispersion characteristics, have been exploited for a variety of applications spanning a range of length scales and covering multiple disciplines in applied physics and engineering, particularly in elastodynamics and acoustics. The intrinsic placement of pillars on a semi-infinite surface—yielding a metasurface—has similarly provided new avenues for the control and manipulation of wave propagation. Classical waves are admitted in pillared media, including Lamb waves in plates and Rayleigh and Love waves along the surfaces of substrates, ranging in frequency from hertz to several gigahertz. With the presence of the pillars, these waves couple with surface resonances richly creating new phenomena and properties in the subwavelength regime and in some applications at higher frequencies as well. At the nanoscale, it was shown that atomic-scale resonances—stemming from nanopillars—alter the fundamental nature of conductive thermal transport by reducing the group velocities and generating mode localizations across the entire spectrum of the constituent material well into the terahertz regime. In this article, we first overview the history and development of pillared materials, then provide a detailed synopsis of a selection of key research topics that involve the utilization of pillars or similar branching substructures in different contexts. Finally, we conclude by providing a short summary and some perspectives on the state of the field and its promise for further future development. [ABSTRACT FROM AUTHOR]

We provide a road towards obtaining gravitational waveforms from inspiraling material binaries with an accuracy viable for third-generation gravitational wave detectors, without necessarily advancing computational hardware or massively-parallel software infrastructure. We demonstrate a proof-of-principle 1 + 1-dimensional numerical implementation that exhibits up to 7th-order convergence for highly dynamic barotropic stars in curved spacetime, and numerical errors up to 6 orders of magnitude smaller than a standard method. Aside from errors associated with overshoot in high-order extrapolation from the interior of the star to the surface, there are no obvious fundamental obstacles to obtaining convergence of even higher order. The implementation uses a novel surface-tracking method, where the surface is evolved and high-order accurate boundary conditions are imposed there. Computational memory does not need to be allocated to fluid variables in the vacuum region of spacetime. We anticipate the application of this new method to full 3 + 1-dimensional simulations of the inspiral phase of compact binary systems with at least one material body. The additional challenge of a deformable surface must be addressed in multiple spatial dimensions, but it is also an opportunity to input more precise surface tension physics. [ABSTRACT FROM AUTHOR]

In this review, we mention about the theoretical achievement of physics of surface Andreev bound state (SABS) and odd-frequency pairing during this quarter century based on our research. Currently, topological superconductors with Majorana edge state have become a central issue in condensed matter physics. It is noted that Majorana edge state is nothing but a zero energy surface Andreev bound state (ZESABS) and the study of ZESABS has started in the context of the pairing symmetry of high Tc cuprate. We mention our obtained conductance formula of quasiparticle tunneling and Josephson current in unconventional superconductor junctions through ZESABS have already captured the essence of the charge transport profile via the Majorana fermion. We also mention that in the presence of ZESABS, odd-frequency pairing like spin-triplet s-wave or spin-singlet p-wave is hugely enhanced near the surface or interface. We further analyze the spectroscopy of the induced odd-frequency pairings by extending bulk-boundary correspondence in ZESABS. If we consider a semi-infinite superconductor with ZESABS, the induced odd-frequency pair amplitude can be expressed by a c-number defined in bulk, which we call spectral bulk-boundary correspondence. The odd-frequency pair amplitude is classified into singular part and regular one, the former part is proportional to ∼ 1 / z (z is a complex frequency) reflecting the presence of ZESABS, and the latter one is proportional to ∼ z . The coefficient of the latter one diverges at the topological phase transition point. Analyzing the spectral behavior of the odd-frequency pairing is useful to understand the critical phenomena near topological transition points. [ABSTRACT FROM AUTHOR]

In this paper, a new beamline optical system design method is reported in which the calculation of synchrotron radiation source flux distribution, monochromator spectral resolving power, mirror reflectance and grating diffraction efficiency are integrated together in one program to evaluate the whole beamline optical system performance. We demonstrate the advantage of this method by applying it to the Surface Physics beamline at Hefei Light Source to find out better optical system parameters. By using this method, a higher photon flux with the same spectral resolving power than the original design is achieved. The integrated optical system design method provides a great promising application in the beamline optical design and optimization in the future. [ABSTRACT FROM AUTHOR]

The dynamic ground effect (DGE) refers to the take-off and landing process where the distance between airplane and ground constantly changes with time. In the wind tunnel experiment of DGE, fixed plates are often adopted to substitute the moving-belt ground, which will affect experimental reliability. In this paper, the landing process of an airfoil is simulated to study the feasibility of fixed plates in the chord-dominated DGE experiment. The height is divided into two regions based on the aerodynamics and flow patterns. In Region I (large height), DGE is dominated by the static ground effect (SGE), using a fixed plate can effectively balance the camber effect, blocking effect and boundary layer effect to reproduce result of the moving-ground condition. In Region II (small height), DGE is dominated by the compression work effect, where the downwash is highly compressed to diverge into a forward stream and a backward stream. When using fixed plates, the downwash exhibits two kinds of escaping behavior: the leading-edge-preferred escaping behavior for most fixed plates due to thick boundary layer and the trailing-edge-preferred escaping behavior for the very short plate due to the suddenly weakened camber effect. No plate can balance the two kinds of flow to accurately reproduce pressure distribution on airfoil lower surface and flow physics of moving-ground condition. Thus, the use of a fixed plate is infeasible. [ABSTRACT FROM AUTHOR]

Growths of novel two-dimensional materials have recently attracted interests to develop chemistry and physics at surfaces. By the boron deposition on Cu(110), we discovered a 1D anisotropic ordered phase, 3 × 1, as a pattern of electron diffraction. The electronic analysis by photoelectron spectroscopy unveiled that the surface superstructure is a layer of the Cu boride with a component of the negatively charged boron atoms. This surface boron atoms likely form the chain structure that is isoelectronic to carbon polymers, such as bumulene that was recently reported on Cu(111). Considering the two-fold rotation symmetry of Cu(110) substrate, the novel surface phase likely becomes an ideal system to examine 1D boron materials. • A 3 × 1 ordered phase was discovered on the boron-deposited Cu(110) surface. • From the XPS measurement, 3 × 1-B/Cu(110) was found to be a Cu boride compound. • It holds similarity with 73 × 39 -B/Cu(111) that has unique 1D boron arrangement. • The new surface phase likely becomes an ideal system to examine 1D boron materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The electro-thermal coupling effect and the thermal–mechanical coupling effect were the basic principles of the coupling field tip enhancement induced with laser irradiated probes. • The thermo-mechanical coupling effect allows an accurate estimation of the probe displacement and avoids mechanical scratching on the sample surface. • Nanostructures with a feature size of approximately λ/20 (23 nm) was obtained. • The essential mechanism of the coupling field tip enhancement interacting with samples is the deposition of total energy on materials. The nanofabrication mechanism of coupling field tip enhancement induced by laser-irradiated probe tip was investigated theoretically and experimentally. The coupling mechanisms and distribution characteristics of the enhanced electric, thermal, and stress fields were studied at wavelengths of 400–800 nm and tip-sample distances of 1–20 nm for 9 material combinations. The simulation results demonstrated that the electro-thermal coupling effect and thermal–mechanical coupling effect are the basic principles of this technique, independent of the materials. It was also demonstrated that probe damage due to mechanical scratching can be avoided through the estimation of probe displacement. The superposition of electromagnetic energy and thermal energy generates an extremely constrained total energy of up to 10–12 orders of magnitude near the tip end. The nano-line structures were processed at each tip-sample distance, and nanostructures with a feature size of approximately λ/20 were obtained. The experimental results and the total energy distribution demonstrated that the interaction of the coupling field tip enhancement with samples is in the form of total energy deposits on materials. The significance of this study will not only enable a refined understanding of the fundamental physics of surface nanostructuring but will also advance the scientific and industrial applications of the technology. [ABSTRACT FROM AUTHOR]

• Metasurface-based retroreflectors have been demonstrated with great attractions and application values. • The concept of high-order EP in 2D scattering channel is firstly presented. • The unidirectional retroreflector based on non-Hermitian physics further provide a new perspective for angular-asymmetric photonic devices for wave manipulation. • Polarization-insensitive retroreflector based on isotropic structure can be realized. Extraordinary angularly asymmetric electromagnetic manipulation is desirable in angle-encoded steganography, directional display, one-side sensing and other unconventional applications, which however is challenging. Here, we build the non-Hermitian surface scattering systems by silicon nano-posts with spatially modulated loss, showing the extraordinary angular-asymmetry in the near infrared regime under different polarized light incidence. Especially a polarization-insensitive unidirectional retroreflector with non-Hermitian metasurface is first demonstrated at a fourth-order exceptional point (EP), related to the collapsed EPs of a generalized 4 × 4 non-Hermitian scattering matrix under TM and TE polarization states. Our investigations provide a new perspective for designing polarization-insensitive asymmetric photonic devices for wave manipulation and applying more generalized non-Hermitian physics to surface scattering systems. [ABSTRACT FROM AUTHOR]

• Effect of an external flux on surface dynamics has been studied by KMC and analytical developments. • Excepted for a vicinal surface, generally it is not possible to compensate surface sublimation with a deposition flux. • The dynamic evolution of the area of a 2D island varies with time as t − α. • In presence of an external flux, the value of α is not enough to identify the limiting mechanisms. Sublimating surfaces are out of equilibrium. It has been proposed that sublimation can be compensated by an impinging atomic flux to obtain equilibrium. This work concerns the effect of such an impinging flux on the stability of surfaces in various situations. For this purpose we combine Kinetic Monte Carlo Simulations with analytical developments based on the Burton-Cabrera-Frank (BCF) classical theory. We show that a perfect compensation of the sublimation is possible for vicinal surfaces but not when 2D islands are present on a surface. We thus study the effect of an impinging flux on the dynamic of a 2D island on a surface. We show that the 2D island area generally varies with time t as − t α. In absence of any impinging flux the value of the exponent α enables to identify the main mechanism at work (diffusion limited or attachment-detachment limited). On the contrary, in presence of an impinging flux the value of the exponent α is not enough to identify the main mechanism limiting the area change. [Display omitted] [ABSTRACT FROM AUTHOR]

The prediction of hydrologic conditions in watersheds has manifold applications, ranging from flood disaster preparedness to water supply and environmental flow management. In watersheds with scarce or no flow data, it is difficult to make accurate hydrologic predictions. Past work has used similarity in single-valued properties of the terrain (for example, drainage area, mean slope) as the basis to relate flow conditions in gauged watersheds to the ungauged ones. The resulting predictions show modest accuracy and have a weak physical basis. In this study, we develop a physics-informed machine learning approach to extract features that represent the hydrologic dynamics — width function and hypsometric curve. These two geomorphometric measures are computed using functional forms fitted to estimates derived from digital elevation data. Furthermore, dynamically-similar groups are identified based on results from unsupervised clustering and divergence measures. Our approach paves the way towards a flexible and scalable machine learning approach that can be used to assess hydrologic similarity and improve prediction, one informed by physics of surface flow generation and transport in watersheds. A case study involving 72 sub-watersheds in the Narmada River Basin (India) is used to illustrate the new methodology. • Unsupervised learning is leveraged to assess hydrological similarity in watersheds • Functional estimates of width function and hypsometry allow watershed classification • Methodology presented can be scaled and affords physics-informed discovery • Dynamical measures of watershed response derived from digital elevation data [ABSTRACT FROM AUTHOR]

Motivated by a strong coupling between bulk and surface physics, we present two approaches to derive continuum surface models from the three-dimensional, adjacent bulk deformation: projection and relaxation. In contrast to conventional ad hoc models, properties like the surface stress are consistently derived from a hyperelastic thermodynamic potential. While the projection approach captures classical in-plane stresses, the relaxation approach can further relax normal-normal and normal-shear coupling. A projection onto the surface is indeed always a relaxation if anisotropy is superficial, but not vice versa. The distinct behavior of projection and relaxation is theoretically discussed and highlighted by specific examples. Numerical implementation in a finite-element framework is subsequently elaborated. Its performance is illustrated by isotropic and anisotropic surface energies of a free cube and a beam under tension. Finally, both projection and relaxation constitute valuable alternatives to conventional surface models in terms of physics, geometry and computation. [ABSTRACT FROM AUTHOR]

As an important carbon material, a nano-crystalline diamond (NCD) film is very promising in the field of science and technology. However, there are little knowledge about surface physics and chemistry of nanoscale in NCD films. Here, we perform nanoscale imaging of NCD films grown by hot filament chemical vapor deposition, using tip-enhanced Raman spectroscopy. With ~20 nm spatial resolution, we resolve nanoscale spatial correlations of trans -polyacetylene segments on the surface with characterized Raman modes at 1150 cm−1 and 1480 cm−1 that originate from the motion of conjugate polymer skeletons with a substantial contribution from the in-plane bending of carbon‑hydrogen bonds and stretching vibrations of the double carbon‑carbon bonds. Our work is helpful to understand the role of TPA in NCD synthesis reaction in nanoscale and improve the device application based on this material. [Display omitted] • Nanoscale TERS imaging of nanodiamond films • Identification of locally spatial distribution of TPA segments on surface • Spatial correlations of TPA segments with Raman modes at 1150 cm−1 and 1480 cm−1 • The role of TPA segments in the diamond synthesis reaction [ABSTRACT FROM AUTHOR]