Surficial Layer Research Articles

Unsaturated modelling, testing and monitoring towards the rehabilitation of a slope on National Route 3, KwaZulu-Natal, South Africa

The stability of over-steep road embankments often worsens with time. In many cases the slope deterioration can be ascribed to continual downslope creep of a surficial layer of soil that has been affected by infiltration of rainfall. Such infiltration reduces the suction in the surficial layer interacting with the environment. With every season the surficial layer moves further downslope, often resulting in cracks in theslow lane and placing structures constructed at the crest of fill slopes in potential jeopardy. A slope on the National Route 3 (N3), in the South African Province of KwaZulu-Natal, constructed at roughly 40° from the horizontal showed signs of distress in the slow lane many years after construction. The rehabilitation of this slope required stabilisation design using unsaturated soil testing, modelling, and in-situ suction measurement. The slope was stabilised using soil nails, a high-tensile steel mesh, and a suction measurement system was installed. An overview of the emergency works design, subsequent investigation, and monitoring is provided in this paper. It was found that the suction profile determined by transient finiteelement analysis matched well with the measured suction profile and provided a good basis for the emergency design works prior to full investigation.

Reconstruction of a surficial P-rich layer on Ni-P electrocatalysts for efficient hydrogen evolution applicable in acidic and alkaline media

Ni-P is a promising catalytic material for the hydrogen evolution reaction (HER) due to its high catalytic activity, highly competitive cost, and practical usefulness. To achieve the best catalytic performance with the Ni-P-based material, it is necessary to control the P ratio in Ni-P because the catalytic kinetics of Ni-P depend on the number of reaction sites of the positively and negatively charged Ni and negatively charged P to adsorb the hydride/hydroxide and proton in acidic and alkaline media. Here, we introduce a facile surface-treatment based on dealloying to control the surficial P ratio with multiple CV cycles. As a result, the 20 and 10 times cycled Ni-P/CFPs show improved catalytic activities of 30.8% and 23.5% along with higher stabilities of 99.8 and 97.9% retention in acid and alkaline media, respectively. In particular, the different kinetics according to P ratio in both acid and alkaline media can be elucidated by DFT calculations of the free energy changes related to each RDS.

Mechanical and Anticorrosive Properties of TiNbTa and TiNbTaZr Films on Ti-6Al-4V Alloy

In this study, TiNbTa and TiNbTaZr films were utilized as protective coatings on a Ti-6Al-4V alloy to inhibit corrosive attacks from NaCl aqueous solution and simulated body fluid. The structural and mechanical properties of multicomponent TiNbTa(Zr) films were investigated. The corrosion resistance of the TiNbTa(Zr)-film-modified Ti-6Al-4V alloy was evaluated using potentiodynamic polarization tests in a NaCl aqueous solution. The results indicate that the TiNbTa(Zr) films with high Ti and Zr contents exhibited inferior corrosive resistance related to the films with high Ta and Nb contents. Moreover, the TiNbTa(Zr)-coated Ti-6Al-4V plates were immersed in Ringer’s solution for eight weeks; this solution was widely used as a simulated body fluid. The formation of surficial oxide layers above the TiNbTa(Zr) films was examined using transmission electron microscopy and X-ray photoelectron spectroscopy, which prevented the elution of Al and V from the Ti-6Al-4V alloy. Ti33Nb19Ta21Zr27, Ti15Nb68Ta8Zr9, and Ti8Nb8Ta79Zr5 films are suggested as preferential candidates for TiNbTa(Zr)/Ti-6Al-4V assemblies applied as biocompatible materials.

Simulation of surface regolith gardening and impact associated melt layer production under ns-pulsed laser ablation

The effect of surface regolith gardening and melt layer production produced by space weathering (SW) (owing to micrometeorite bombardment) of surficial regolith layers of airless planetary surfaces was investigated in an experimental setup by using laser-induced ablation of powdered analog material (synthetic Fo100) under vacuum with a ns-pulsed infrared laser. The investigated analog pellets were prepared from the fine fraction (< 1 μm) up to a grain size of 280 μm, which resembles the uppermost regolith surface of many airless planetary bodies. The Fo-powder was pressed into shape to form a pellet. We focused here on nanometer-sized structural modifications that are induced in the relocated grains, sputtered off ejecta material and melt sprinkles that formed away from the craters caused by laser irradiation of the pressed pellet surface. The ejecta particles were redistributed over the entire pellet surface and beyond. The forming sputter film, melt sprinkles and ballistically ejected grains were caught on carbon film grids positioned nearby the craters. The grids were investigated with a transmission electron microscope (TEM) to discern between the distinct deposition types that were formed by ejecta condensate and partially molten ejected nanometer-size analog grains. Apart from a heavily modified pellet surface, we found that deposited droplets are mostly amorphous with minor nanocrystalline subdomains. Eight out of ten droplets show distinct incipient crystallization stages. This indicates at a relatively high amount of amorphous regolith material at the incipient stage of SW for airless bodies, if the regolith is altered via micrometeorite bombardment.

Stimulated leaching of metalloids along 3D-printed fractured rock vadose zone

Fractured rock aquifers are susceptible to contamination, with metal(loid)s rapidly migrating from poorly developed overburden to the fractured rock vadose zone and thus into groundwater. Compared to typical porous aquifers, retention effects within the rock matrix are small, and rapid advection along fractures leads to a higher risk of groundwater contamination. However, the highly complex anisotropic pathways of natural fractures hinder research in this field. To construct reproducible fractures, this study used 3D printing following Computed X-ray Microtomography (μCT) scans of a fractured rock collected in a natural limestone aquifer. Stimulated metalloid release was observed in the fractured rock during column leaching, and the leachate concentrations of arsenic (As) and antimony (Sb) increased by up to 17.5 and 36.4 times, respectively, compared with the porous vadose zone. Fluctuations in fracture metalloid release patterns in dissolved and adsorbed phases were attributed to retention and filtration effects induced by soil particles within fractures. Geophysical properties of the porous overburden, especially the aggregation characteristics, greatly affected the non-equilibrium leaching behavior of As, but had a limited effect on the near-equilibrium leaching of Sb, which was explored by modifying the surficial soil layer with either montmorillonite clay or charcoal. The results of this study provide a novel method and useful information for modeling and risk assessment of fractured rock aquifers.

Pharmaceutical Biotransformation is Influenced by Photosynthesis and Microbial Nitrogen Cycling in a Benthic Wetland Biomat

In shallow, open-water engineered wetlands, design parameters select for a photosynthetic microbial biomat capable of robust pharmaceutical biotransformation, yet the contributions of specific microbial processes remain unclear. Here, we combined genome-resolved metatranscriptomics and oxygen profiling of a field-scale biomat to inform laboratory inhibition microcosms amended with a suite of pharmaceuticals. Our analyses revealed a dynamic surficial layer harboring oxic-anoxic cycling and simultaneous photosynthetic, nitrifying, and denitrifying microbial transcription spanning nine bacterial phyla, with unbinned eukaryotic scaffolds suggesting a dominance of diatoms. In the laboratory, photosynthesis, nitrification, and denitrification were broadly decoupled by incubating oxic and anoxic microcosms in the presence and absence of light and nitrogen cycling enzyme inhibitors. Through combining microcosm inhibition data with field-scale metagenomics, we inferred microbial clades responsible for biotransformation associated with membrane-bound nitrate reductase activity (emtricitabine, trimethoprim, and atenolol), nitrous oxide reduction (trimethoprim), ammonium oxidation (trimethoprim and emtricitabine), and photosynthesis (metoprolol). Monitoring of transformation products of atenolol and emtricitabine confirmed that inhibition was specific to biotransformation and highlighted the value of oscillating redox environments for the further transformation of atenolol acid. Our findings shed light on microbial processes contributing to pharmaceutical biotransformation in open-water wetlands with implications for similar nature-based treatment systems.

Sound speed profile estimation in a thick mud layer from travel time data

The sound speed profile in a surficial mud layer is of importance because it controls what is acoustically illuminated within and below the mud layer. A variety of estimates have been made at the New England Mud Patch (NEMP) with some near-surface sound speed gradients as large as 10 s−1 and larger. Here, single bounce seabed reflection travel time data are used to infer what mud sound speed gradients are and are not plausible near the central NEMP region where the mud thickness is ∼10 m. Time series data were collected on a moored hydrophone from a broadband source with a 1 second repetition rate as the tow ship transited on a radial from the hydrophone to a distance of ∼1 km at a speed of 2 m/s. The water column was essentially isovelocity and grazing angles ranged from 4.5° to 84°. It is known that at the base of the mud, there is a mud-sand transition layer (of order 1 m thick) where sound speed gradients can be large. However, above this layer, the travel time data clearly indicate that a mud 10 s−1 sound speed gradient is too large. [Research supported by ONR Ocean Acoustics Program.]

Acoustic modeling of ducted propagation in the New England Mud Patch

Experiments were conducted on the New England Mud Patch in 2017, 2021, and 2022. The 2017 Seabed Characterization Experiment (SBCEX17) utilized Signal Underwater Sound (SUS) charges, model Mk64, to produce an impulsive acoustic waveform. However, recent work in 2022 has additionally utilized the Rupture Induced Underwater Sound Source (RIUSS) to produce a high-amplitude, broadband waveform with minimal bubble oscillations. Results from these experiments suggested the presence of a surficial layer of mud with a sound speed lower than that of the underlying mud and overlying water. The SBCEX22 experiment included the deployment of nine RIUSS devices and the use of Ocean Bottom Recorders (OBX) to measure the acoustic pressure and three components of particle velocity at range of about 1 km. Conductivity, temperature, and depth measurements from CTD surveys were taken from several locations around the mud patch and used to generate sound speed profiles. These were input into the RAM parabolic equation model to analyze the effect of the sound speed in mud on propagation. Results from the RAM modeling indicates that at mid-frequencies (1-3 kHz) the lower sound speed at the top of the mud layer creates a duct where the transmission loss is reduced.

Capacitance–voltage characterization of metal–insulator–semiconductor capacitors formed on wide-bandgap semiconductors with deep dopants such as diamond

As diamond possesses only deep dopants, certain conventional physics and characterization methods are not applicable to diamond devices, owing to the explicit or implicit assumption of shallow dopants. To resolve this limitation, the capacitance–voltage (C–V) characteristics of metal–insulator–semiconductor (MIS) capacitors formed on a semiconductor substrate with deep and compensating dopants were successfully formulated. Based on these equations, methods for accurately estimating the MIS capacitor properties were developed and validated through their application in the analysis of an actual MIS capacitor formed on a boron-doped hydrogen-terminated diamond substrate. The high-frequency C–V characteristic of the capacitor exhibited a prominent dip specific to deep dopants. However, the dip depth was considerably shallower than theoretically expected. This C–V characteristic was accurately reproduced theoretically, assuming the presence of a surficial diamond layer that contains acceptors with an activation energy of 0.23 eV, which is less than the value 0.37 eV for boron, and has a thickness of the extrinsic Debye length (40 nm in this study) or larger. The insulator charge of the MIS capacitor was estimated as −4.6 × 1012 cm−2 in units of electronic charge, which is sufficiently large to induce two-dimensional hole gas. The interface-state density was 1.4 × 1012 cm−2 eV−1 for interface-state energies of 0.3–0.5 eV above the valence band maximum. Hence, the proposed methodology and the possible presence of the reduced activation energy layer will guide the development of diamond-based devices.

Characterization of vegetated and ponded wetlands with implications towards coastal wetland marsh collapse

Coastal wetlands provide numerous ecosystem services; yet these ecosystems are increasingly vulnerable to climate change stressors, especially excessive flooding from sea-level rise and storm events. This study highlights the important contribution of vegetation belowground biomass to marsh stability and identifies loss of vegetation as a critical driver of marsh collapse. We investigated the shear strength of salt marshes and unvegetated interior ponds using a modified cone penetrometer along a chronosequence of wetland marsh collapse (0 to 21 + years following pond formation) to characterize changes in the structural integrity of the marsh soil. Following conversion from vegetated marsh to open water pond, the surficial soils experienced a dramatic loss in shear strength resulting from the loss of vegetation and compaction of soil pore space. The Cone Penetrometer Testing (CPT) data indicate that higher shear strength in the surficial layers of the vegetated marsh sites were never recovered, up to 21 + years following marsh collapse. Coupled with significant elevation loss from marsh collapse, additional sea-level rise, deep subsidence, and reduced sedimentation may contribute to conditions that can exceed critical flooding thresholds, making recovery from marsh collapse difficult or impossible. Therefore, characterizing mechanisms and thresholds of marsh collapse are critical for identifying those coastal marshes that are vulnerable to collapse before conversion from vegetated marsh to open water occurs.

Preparation of nitrile butadiene rubber/fly ash composites by designing a surficial immobile layer

AbstractFly ash (FA), a solid waste product from thermal power stations, can be served as a nonreinforcing filler for polymers. Due to the lack of hydroxyl groups of FA, it is infeasible to prepare polymer composites with excellent properties by coupling agents. In this work, high performance nitrile butadiene rubber (NBR)/FA composites were prepared by designing a surficial immobility layer. First, the carboxyl group of sorbic acid (SA) undergoes interfacial acid‐base neutralization reaction with metals oxide of FA to form ionic bonds. Second, the double bonds of SA can graft to NBR molecular chains with the assistance of a peroxide initiator. Consequently, 500% modulus and tensile strength of NBR/30FA/8SA composites are higher than those of NBR/30FA composite by 213.8% and 125.9%, respectively, which makes FA changing from the nonreinforcing filler to reinforcing filler and provides a new way for the large‐scale utilization of FA in the polymer industry.

Regularities of the creep deformation and failure of 15Kh2NMFA-A steel within the temperature range of 900–1200 °C

This paper presents and summarizes main results of the research to define the high-temperature creep parameters and strength characteristics of the unirradiated steel 15Kh2NMFA-А tested in the temperature range of 900–1200 °C. This ferritic-pearlitic steel is one of the main types of steel used for the production of the VVER RPVs of the Russian design. The results of research of the strength properties and creep parameters for 15Kh2NMFA-А steel are meant to support, first and utmost, the estimation of the integrity and predicting the behavior of the VVER pressure vessel during the SA, when it may deform due to high-temperature creep and the overpressure in the RPV. One of the main goals of the investigation was to determine such strength properties and creep parameters of the investigated steel as, for instance, steady-state creep rate, creep tensile strength under the condition of isothermal creep at different temperatures and test stress. The creep tensile tests were conducted in vacuum and in the protective argon medium. A series of creep tests was conducted in air. The analysis and comparison of the test results demonstrated significant impact of the surficial oxidation process on the nature of their damage and the time to failure of the test samples. The absence of a protective medium during testing, as observed in the case of the test in air, causes decarburization and the damage of the surficial layer of the steel samples, so that the specimen fractures prematurely. Based on the statistic estimation the (B) and (n) parameters for the secondary creep rate equations were defined for the researched steel within the temperature range of 900–1200 °C. The agreement between the values of the steady-state creep rate of 15Kh2NMFA-A steel from the conducted creep tensile tests and similar calculation values from the obtained parameters (B) and (n) for the temperature range from 900 to 1200 °C was satisfactory. The paper also presents the definition of the LMP parametric dependence coefficients, completed on the basis of the creep test results for 15Kh2NMFA-А steel with a time span up to 100 h in the given temperature range. The comparative analysis of the defined LMP dependence demonstrated good agreement of the predicted values for the failure time with similar values defined during the experiment.The research of the steel specimens’ microstructure following the tests demonstrated a difference in the mechanisms of damage accumulation and fracture at the temperatures over 1000 °C in comparison to similar mechanisms at lower temperatures. It is important to apply more precise research methods to understand this phenomenon to a better extent; such research may take place later.

Mitigating the Surface Reconstruction of Ni-Rich Cathode via P2-Type Mn-Rich Oxide Coating for Durable Lithium Ion Batteries.

Ni-rich materials have received widespread attention as one of the mainstream cathodes in high-energy-density lithium-ion batteries for electric vehicles. However, Ni-rich cathodes suffer from severe surface reconstruction in a high delithiation state, constraining their rate capabilities and life span. Herein, a novel P2-type NaxNi0.33Mn0.67O2 (NNMO) is rationally selected as the surficial modification layer for LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode, which undergoes a spontaneous Na+-Li+ exchange reaction to form an O2-type LixNi0.33Mn0.67O2 (LNMO) layer revealed by combining X-ray diffraction and solid-state nuclear magnetic resonance techniques. Owing to the specific oxygen stacking sequence, O2-type LNMO significantly prevents the initial layered structure of NCM811 from transforming to the spinel or rock-salt phases during cycling, thus effectively maintaining the integral surficial structure and the Li+ diffusion channels of NCM811. Eventually, the NNMO@NCM811 electrode yields enhanced thermal stability, outstanding rate performance, and long cycling stability with 80% capacity retention after 294 cycles at 200 mA g-1, and its life span is further extended to 531 cycles while enhancing the mechanical stability of the bulk material.

Microsized aluminum/ammonium dinitramide core-shell particles to improve the combustion performance of aluminum powders

Microcomposite particles of aluminum (Al) dotted by ammonium dinitramide (ADN) ([email protected]) are successfully prepared by an in-situ crystallization growth method. The morphologies, structures and thermal behavior of [email protected] are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and simultaneous thermogravimetry and differential scanning calorimetry. The compositions and morphologies of [email protected] after heating are characterized by X-ray photoelectron spectroscopy (XPS) and SEM. A high-speed camera is used to record the combustion performances of [email protected] in a transparent quartz tube. Furthermore, the morphologies and structures of the residues are analyzed by SEM and XRD. The results show that ADN is deposited on the surface of Al to form [email protected] The decomposition of ADN increases the total oxidation degree of the Al particles. Under heating, the acids decomposed by ADN corrode the surficial alumina layer and the internal aluminum react with HNO3 to form Al(NO3)3, which makes the combustion of Al easier. Under an oxygen atmosphere, the pure Al could not be ignited. In contrast, [email protected] could be ignited and [email protected] 5:1 has a shorter ignition and burning time compared with [email protected] 10:1. After burning, the [email protected] composites are completely converted to α- and γ-Al2O3. For [email protected] 10:1, the residues show a cube-like stacking, while a ribbon-like stacking is presented for [email protected] 5:1.

Centrifuge modelling of wave-induced seabed response in clay

This paper describes a programme of centrifuge tests investigating the behaviour of clayey seabed under wave loading using an in-flight wave loading system. Three model seabeds of kaolin clay capturing typical unconsolidated, normally consolidated and overconsolidated soil responses were considered, with each seabed experiencing several episodes of wave loading and resting. Data acquisition measures included pore pressure transducers, accelerometer, bender elements and T-bar penetrometers. The depth-wise distribution of excess pore pressure, soil strength and modulus, as well as the motion of the liquefied layer of the seabed, was monitored throughout to enable a thorough investigation into the liquefaction and reconsolidation features of the soil. For the unconsolidated and normally consolidated soils, remarkable development of residual pore pressure was observed, and there was evidence that the strength/modulus recovery cannot be achieved by the surficial soil within a prototype time of 15 days. Within a certain depth below this surficial layer, there was a drastic increase in undrained strength, and this phenomenon was carefully examined by a modified moving-boundary model. For the overconsolidated soil, the build-up of residual pore pressure was rather limited, but discernible amplification of oscillatory pore pressure amplitude was observed. Implications for practice in offshore engineering are discussed based on the experimental findings.

Response of Living Benthic Foraminifera to Anthropogenic Pollution and Metal Concentrations in Saronikos Gulf (Greece, Eastern Mediterranean)

The Saronikos Gulf, including the industrial zone of Elefsis Bay, is subjected to a variety of urban and industrial impacts that significantly contribute to environmental degradation. Benthic foraminifera comprise a significant component of meiobenthic communities and they are widely used as reliable indicators for the determination of the natural environmental and anthropogenic impact in shallow coastal systems. The present study analyses the living benthic foraminifera composition and its relation to environmental parameters such as grain size, organic carbon content, and heavy metal concentrations, from the surficial sediment layer collected in the Elefsis Bay and the Inner Saronikos Gulf in February 2016. Canonical correspondence analysis and Spearman’s rho correlation show that the foraminiferal species composition is significantly influenced by the increase of organic carbon and Cu, Pb, Zn content. In particular, a relatively low diversity fauna dominated by the stress-tolerant species Ammonia tepida, Bulimina elongata, Bulimina marginata, and Nonionella turgida occurs in the restricted environment of the Elefsis Bay, demonstrating the negative environmental impact caused by the relatively elevated organic carbon and heavy metal contents.

Fragility analysis of a pipeline under slope failure-induced displacements occurring parallel to its axis

Providing urbanized centers with hydrocarbon supplies from remote production centers, transmission pipelines run for thousands of kilometers, inevitably traversing mountainous and rugged terrain, where slope failure is the dominant source of risk. Strategies to manage these risks heavily depend on the quantification of uncertainty. To this end, this paper presents a fragility analysis framework to quantify the effect of uncertainties, that makes use of a Random Forests algorithm as a surrogate model to thoroughly explore the uncertain parameter space. The Random Forests algorithm is trained and tested against a small, yet statistically significant sample of Sliding Slope-Pipeline Interaction (SSPI) cases that are meticulously analyzed using a rigorous 3D continuum-based numerical methodology. The fragility analysis framework is applied to a 36 in. pipeline descending a slope, with possible soil movement occurring parallel to its axis. Uncertainty stems from the variability in soil properties (friction angle, cohesion and density), in pipe steel material properties (yield strength), in the magnitude of operational loads (pressure and temperature) and in the pipeline placement depth around their expected values, as well as from the lack of knowledge of the geological conditions (the depth of the eroded surficial layer) that ultimately control the shape of the failure surface. Τhe significance of each uncertain variable on the response of the pipeline is investigated, concluding that the depth and shape of the failure surface (correlated with the depth of the surficial layer) is be the most influential parameter, governing the pipeline performance and ultimately the safety thresholds.

Acoustic resonances within the surficial layer of a muddy seabed.

This is an investigation of sound propagation over a muddy seabed at low grazing angles. Data were collected during the 2017 Seabed and Bottom Characterization Experiment, conducted on the New England Mud Patch, a 500 km2 area of the U.S. Eastern Continental Shelf characterized by a thick layer of muddy sediments. Sound Underwater Signals (SUS), model Mk64, were deployed at ranges of 1-15 km from a hydrophone positioned 1 m above the seafloor. SUS at the closest ranges provide measurements of the bottom reflection at low grazing angles (<3 deg). Broadband analysis from 10 Hz to 10 kHz reveals resonances in the bottom reflected signals. Comparison of the measurements to simulated signals suggest a surficial layer of mud with a sound speed lower than the underlying mud and overlying water. The low sound speed property at the water-mud interface, which persists for less than 1 m, establishes a sound duct that impacts mid-frequency sound propagation at low grazing angles. The presence of a low-speed surficial layer of mud could be universal to muddy seabeds and, hence, has strong implications for mid-frequency sound propagation wherever mud is present.

Crystalline silicon photovoltaic module degradation: Galvanic corrosion and its solution

Corrosion is a significant cause of degradation of silicon photovoltaic modules. In this study, the corrosion of multicrystalline passivated emitter and rear cells (PERC) was investigated using both experimental and numerical approaches to identify high-corrosion locations and their effect on cell parameters. Corrosion environments were simulated by immersing the device in acetic acid solution at various dwell times. The impact of the acetic acid concentration and relative humidity was examined. Thermodynamic and kinetic analyses of corrosion were performed using a Pourbaix diagram and finite element analysis, respectively. The results indicate that the device power reduces slowly in pure water but is faster in acidic environments at dwell times below 96 h. The power loss was over 60% in all environments at a dwell time of 144 h. In particular, a rapid power loss over 40% was observed at a high acetic acid concentration of 20 wt% after a dwell time of merely 48 h. The power loss in the water environment can essentially occur due to the formation of a surficial metal oxide layer, while in an acidic environment, it may be due to corrosion and/or metal electrode dissolution. The simulation and experimental results demonstrate that the rear aluminum around the silver contact suffers crucially from corrosion; thus, it is the main cause of device power losses. A polymer (EPDM) efficiently prevents water penetration into the electrode areas, thus minimizing power loss due to corrosion, and effectively solves the problem without impacting the production cost.

Landing Site Selection and Characterization of Tianwen‐1 (Zhurong Rover) on Mars

AbstractThe Chinese Mars rover Zhurong onboard the Tianwen‐1 probe successfully landed on Mars in May 2021. Here, we report our efforts in selecting a landing site for Zhurong within a pre‐identified landing region in southern Utopia Planitia. Using the high‐resolution images collected by a camera onboard the Tianwen‐1 orbiter, the landing region was analyzed in detail in terms of surface slopes, crater densities and rock abundances, which enabled the optimized determination of a landing ellipse (56 × 22 km for the major and minor axes) with minimum hazards and assisted the successful landing of the Zhurong rover. We also characterized the landing site and region after landing. Surface images captured by a camera onboard the Zhurong rover revealed a low rock abundance of approximately 4% at the landing site, similar to the rock measurements from orbital data before landing. Images of the surface features and a hole excavated by the pulsed retrorockets beneath the lander suggested a shallow regolith structure with a surficial layer of dust and sand over a layer of duricrust, and brecciated/fragmented rocks and bedrocks beneath. Crater size‐frequency distribution analysis indicated that the landing region might have experienced multiple episodes of resurfacing.