Microscopic Scale Research Articles

Schramm-Loewner Evolution in 2D Rigidity Percolation.

Amorphous solids may resist external deformation such as shear or compression, while they do not present any long-range translational order or symmetry at the microscopic scale. Yet, it was recently discovered that, when they become rigid, such materials acquire a high degree of symmetry hidden in the disorder fluctuations: their microstructure becomes statistically conformally invariant. In this Letter, we exploit this finding to characterize the universality class of central-force rigidity percolation (RP), using Schramm-Loewner evolution (SLE) theory. We provide numerical evidence that the interfaces of the mechanically stable structures (rigid clusters), at the rigidification transition, are consistently described by SLE_{κ}, showing that this powerful framework can be applied to a mechanical percolation transition. Using well-known relations between different SLE observables and the universal diffusion constant κ, we obtain the estimation κ∼2.9 for central-force RP. This value is consistent, through relations coming from conformal field theory, with previously measured values for the clusters' fractal dimension D_{f} and correlation length exponent ν, providing new, nontrivial relations between critical exponents for RP. These findings open the way to a fine understanding of the microstructure in other important classes of rigidity and jamming transitions.

Mathematical modelling and optimal control analysis of pandemic dynamics as a hybrid system

The study of epidemics using mathematical modelling is critical in understanding its dynamics and proposing potential control measures. We propose a generalised epidemiological model corresponding to a pandemic wherein its dynamics is represented as a novel hybrid system obtained by coupling a deterministic model with a stochastic model. The hybrid system dynamics is established in individualistic (macroscopic) and intra-individualistic (microscopic) scales. The established hybrid system is then considered the basis for an optimal control problem, with the rate of vaccination and velocity of spatial dynamics taken as the control parameters affecting the system’s trajectory. We define the cost functional constituted by the continuous cost corresponding to the deterministic model and discrete costs corresponding to the transitions in the microscopic scale. The objective of the control problem is to find an optimal control pair of vaccination rate and spatial velocity, which minimises the cost functional. We use the Dynamic Programming Principle (DPP) as the optimisation technique, followed by verification of the value function obtained by DPP as a viscosity solution of the appropriate Hamilton–Jacobi–Bellman equation to analyse the existence of an optimal control pair to the hybrid system. We prove the existence of optimal controls to the multi-scale dynamics for pandemic modelling, along with an abstract method to synthesise it.

Entropy engineering enhances the electromagnetic wave absorption of high-entropy transition metal dichalcogenides/N-doped carbon nanofiber composites.

Entropy engineering strategies provide a broader platform for exploring the behavior of electromagnetic wave (EMW) absorption materials and their absorption mechanisms on the microscopic scale. In this work, a novel entropy engineering strategy was developed to improve the EMW absorption properties of MoS2. A hierarchical N-doped carbon nanofiber/MoS2 (NCNF/MS) composite was synthesized using the electrospinning and hydrothermal methods. Then, the conformational entropy of MoS2 was increased by sequentially integrating elements such as W, Se, and Te. Although MoS2 maintains a single 2H-phase structure throughout the entropy increase process, it triggers a series of complex changes at the microscopic level, including lattice distortion, ingenious electronic structure adjustments, and an increase in defect density. These changes provide more possibilities for the EMW interaction with the absorber, which significantly enhances the dielectric behavior of the composites, including conduction and polarization losses. Owing to the unique hierarchical structure and rich defect structure, the obtained entropy-increased NCNF/MWSST exhibits excellent EMW absorption performance. The minimum reflection loss reaches -60.7 dB, and the maximum effective absorption bandwidth is 6.48 GHz, which is improved by almost 584% and 810% compared to NCNF/MS. This study provides a new way to design efficient and high-performance MoS2-based absorbers and provides valuable insights for exploring the entropy-increasing strategies to optimize the EMW absorption properties.

Master Role of Hypoxia in Cancer Progression: Major Insights During ISOTT's Half-Century.

On the occasion of ISOTT's half-century, in this chapter, tumour hypoxia (i.e. critically reduced oxygen levels on macro- and microscopic scales), recently classified as an additional hallmark of cancer, its various aetiology-related classifications (diffusion- or perfusion-limitations, hypoxaemic), time-frames of exposure (acute, chronic, cyclic), and different levels (moderate, mild, severe) within and across tumours, and its Janus-face-like role ("dichotomy") in tumour regression (e.g. apoptosis, necrosis) versus "adaptive" tumour progression have been updated and summarised. This latter knowledge is, to a great extent, based on (a) direct, reliable assessments and mapping of the heterogeneous tumour oxygenation status using minimally invasive polarographic pO2 microsensors in clinical settings since the late 1980s, and (b)the discovery of the hypoxia-inducible factors (HIFs) in the early 1990s. These data have clarified the role of hypoxia in stimulating a variety of biologic responses that mediate cancer progression through changes (a) in the genome (associated with clonal selection and expansion), (b) in the transcriptome, and (c) in the proteome, as well as its role as a barrier to the effectiveness of anti-cancer therapies.

Evaluation for water stability of bitumen mixture with multi-scale method

The interaction forces were investigated between matrix bitumen and four kinds of aggregates, including basalt, granite, limestone A, and limestone B in various pH solutions. The aim was to accurately evaluate the water damage resistance of bitumen mixtures at macroscopic and microscopic levels with a conjunctive method of boiling water tests, atomic force microscopy (AFM) colloidal probe technique, zeta potential measurements, and molecular dynamics simulation. Macroscopic evaluation was conducted through indoor water-boiled flaking rate tests to analyze the flaking rate and adhesion class of bitumen and aggregate. The microscopic forces were measured by AFM probe technique between bitumen and aggregate, zeta potential measurements were carried out and the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was employed to interpret the bitumen–aggregate interaction behaviors. Molecular dynamics simulations were considered to explain the interface binding tendency between bitumen and aggregate. The AFM force measurements showed that the long-range repulsion forces changed to attractive forces and high adhesive forces with the pH change from 4 to 6. However, the strong long-range repulsive forces were decreased, compounded with a relative low adhesion in the alkaline solution. The long-range force between granite and bitumen was a strong attraction, and adhesion was strong when the solution pH was 4, which is a more special phenomenon. It may be due to the electrostatic attraction between the positive charge on the granite surface and the negative charge on the bitumen surface. Zeta potential values of bitumen droplets and aggregate particles exhibited an overall decreasing trend with increasing solution pH, and the variation of surface potential value is consistent with the variation trend of long-range force between aggregate and bitumen. The microscopic forces between bitumen and aggregate measured by AFM were validated by molecular dynamics simulations, revealing a strong correlation between debonding work and interfacial forces. The results indicate that the adhesion between aggregates and bitumen in aqueous solution followed the order: limestone A > limestone B > basalt > granite, and alkaline conditions are not conducive to preventing water damage in bitumen mixtures. It provides insights into the water stability mechanism of bitumen-aggregate at macroscopic and microscopic scales, offering theoretical support for preventing water damage in bitumen pavements.

Atomic force microscopy observation of surface morphologies and measurements of local contact potential differences of amorphous solid water samples deposited at 15 and 100 K.

We use an ultra-high vacuum cryogenic atomic force microscope to investigate the surface morphology of amorphous solid water (ASW) prepared by oblique deposition of water vapor onto Si(111)7 × 7 substrates at temperatures of 15 and 100 K. Height-height correlation function analysis of topographic images suggests that ASW at 15 K has a columnar structure and that the typical diameter of the column is 5-10 nm. At 100 K, the typical diameter is 10-30 nm, although columnar features are less prominent. The surface roughness (i.e., deviation of the height) is greater at 15 K than at 100 K, indicating that the surface at 100 K exhibits a relatively flat morphology. This result implies that transient diffusion of deposited water molecules affects the surface morphology at 100 K. In addition, measurements of the local contact potential difference between the tip and the ASW surface suggest that the magnitude of the negative surface potential at the microscopic scale, which is attributed to spontaneous polarisation, cannot simply be scaled by the thickness of ASW as predicted in previous experiments with Kelvin probes.

Particle clogging mechanisms in hyporheic exchange with coupled lattice Boltzmann discrete element simulations

The clogging of a stream bed has a significant impact on the exchange of water between a river and groundwater, known as hyporheic exchange. Clogging issues in orifices influenced by fluid flow have long been a concern, particularly in understanding clogging mechanisms and particle dynamics. This study focuses on investigating the behavior of poly-dispersed particle systems in the Shanghai soft soil using a coupled lattice Boltzmann method and a discrete element method (LBM-DEM). A particle-orifice model was developed based on LBM-DEM to study the clogging problem. Three different orifice diameters with the same particle size distribution were set at a microscopic scale. The simulation results indicate that the primary form of clogging is the formation of particle domes, exhibiting distinct characteristics depending on orifice size. As the orifice size increases, clogging becomes more challenging. Interestingly, the flow rate of fluid passing through clogged orifices is quite complex, as it does not decrease significantly. The formation process of the particle structure shows significant randomness, posing challenges for quantitative analysis and experimental validation. This study provides insights into the initial stages of clogging formation, leading to a better understanding of hyporheic exchange phenomena in stream bed ecosystems.

Trans-Stilbene aggregates and crystallites in polystyrene films: microscopy and spectroscopy studies.

Solid and liquid stilbene forms were characterized using a range of techniques, including atomic force microscopy, coherent anti-Stokes Raman scattering microspectroscopy and optical spectroscopy. The obtained experimental results were analyzed by means of quantum chemical calculations and using a non-negative matrix factorization algorithm. It was confirmed that pure cis-stilbene formed a homogeneous fluid film on a glass substrate, whereas pure trans-stilbene formed crystals. Mixtures of trans-stilbene and polystyrene were shown to form stable solid films, which were non-homogeneous on the microscopic scale: stilbene molecules self-organized into microcrystals, which floated on the surface of polystyrene glass.

MULTISCALE MECHANOBIOLOGICAL MODELING OF THE CORTICAL/SPONGY INTERFACE USING FINITE ELEMENTS

In this paper, we describe a mathematical model of bone remodeling that integrates the activities of the bone cells and the mechanical behavior of the bone in an intermediate cortical/trabecular zone. This behavior decreases and increases as the bone moves from a dense cortical zone to a less dense porous trabecular zone. The bone remodeling is a combined process of resorption and formation driven primarily by osteoclasts and osteoblasts. The evolution of the bone cell population involves osteoblast-osteoclast signaling, which is mediated by the biological factors and receives a mechanical stimulus assessed at the microscopic scale. Excessive stress on the bone causes microdamage that induces changes in the structural integrity and microarchitecture. This phenomenon explains the attention paid to the mechanical properties of the bone. In this context, numerical simulations were performed in a mechanobiological model, in which different mechanical and biological parameters were considered. A three-dimensional finite-element model of a human proximal femur was generated, and the simulation of the bone remodeling algorithm was implemented. The current work is an exploratory numerical study, and the results obtained reveal the impact of the mechanical properties on the remodeling process of the intermediate bone subjected to cyclic loading, highlighting the effects of the selected parameters for the different remodeling periods.

Solution of the discrete Boltzmann equation: Based on the finite volume method

Mesoscopic methods serve as a pivotal link between the macroscopic and microscopic scales, offering a potent solution to the challenge of balancing physical accuracy with computational efficiency. Over the past decade, significant progress has been made in the application of the discrete Boltzmann method (DBM), which is a mesoscopic method based on a fundamental equation of nonequilibrium statistical physics (i.e., the Boltzmann equation), in the field of nonequilibrium fluid systems. The DBM has gradually become an important tool for describing and predicting the behavior of complex fluid systems. The governing equations comprise a set of straightforward and unified discrete Boltzmann equations, and the choice of their discrete format significantly influences the computational accuracy and stability of numerical simulations. In a bid to bolster the reliability of these simulations, this paper utilizes the finite volume method as a solution for handling the discrete Boltzmann equations. The finite volume method stands out as a widely employed numerical computation technique, known for its robust conservation properties and high level of accuracy. It excels notably in tackling numerical computations associated with high-speed compressible fluids. For the finite volume method, the value of each control volume corresponds to a specific physical quantity, which makes the physical connotation clear and the derivation process intuitive. Moreover, through the adoption of suitable numerical formats, the finite volume method can effectively minimize numerical oscillations and exhibit strong numerical stability, thus ensuring the reliability of computational results. Particularly, the MUSCL format where a flux limiter is introduced to improve the numerical robustness is adopted for the reconstruction in this paper. Ultimately, the DBM utilizing the finite volume method is rigorously validated to assess its proficiency in addressing flow issues characterized by pronounced discontinuities. The numerical experiments encompass scenarios involving shock waves, Lax shock tubes, and acoustic waves. The results demonstrate the method's precise depiction of shock wave evolution, rarefaction waves, acoustic phenomena, and material interfaces. Furthermore, it ensures the conservation of mass, momentum, and energy within the system, as well as accurately measures the hydrodynamic and thermodynamic nonequilibrium effects of the fluid system. Compared with the finite difference method, the finite volume method is also more convenient and flexible in dealing with boundary conditions of different geometries, and can be adapted to a variety of systems with complex boundary conditions. Consequently, the finite volume method further broadens the scope of DBM in practical applications.

Tuning catalytic performance of platinum single atoms by choosing the shape of cerium dioxide supports.

The local coordination environment of single atom catalysts (SACs) often determines their catalytic performance. To understand these metal-support interactions, we prepared Pt SACs on cerium dioxide (CeO2) cubes, octahedra and rods, with well-structured exposed crystal facets. The CeO2 crystals were characterized by SEM, TEM, pXRD, and N2 sorption, confirming the shape-selective synthesis, identical bulk structure, and variations in specific surface area, respectively. EPR, XPS, TEM and XANES measurements showed differences in the oxygen vacancy density following the trend rods > octahedra > cubes. AC-HAADF-STEM, XPS and CO-DRIFTS measurements confirmed the presence of only single Pt2+ sites, with different surface platinum surface concentrations. We then compared the performance of the three catalysts in ammonia borane hydrolysis. Precise monitoring of reaction kinetics between 30-80 °C gave Arrhenius plots with hundreds of data points. All plots showed a clear inflection point, the temperature of which (rods > octahedra > cubes) correlates to the energy barrier of ammonia borane diffusion to the Pt sites. These activity differences reflect variations in the - facet dependent - degree of stabilization of intermediates by surface oxygen lone pairs and surface-metal binding strength. Our results show how choosing the right macroscopic support shape can give control over single atom catalysed reactions on the microscopic scale.

Biofunctionalized Waste Brick Powder to Enhance Performance of Blend Cement Mortar

Utilizing waste brick powder (BP) as an alternative binder in cementitious materials is a low‐cost option for recycling waste BP. However, the degradation of concrete properties triggered by the low activity of brick dust is still a widespread concern. Hence, this study utilizes plant‐based tannic acid (TA) to modify BP, enhancing its surface activity and achieving high‐value utilization of the BP. The research content involves studying the physicochemical changes on the surface of modified BP and analyzing its impact on the mechanical properties of mortar at macroscopic and microscopic scales. The study shows that TA mainly adheres to the BP surface through O─C═O and C─OH bonding and in situ chelates with calcium elements to form nanoscale microcrystals (as evidenced by X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) tests). These phenolic hydroxyl groups and nano‐microcrystals collectively regulate cement hydration, resulting in a dense pore structure and a homogeneous BP‐paste hydration interface (as confirmed by nanoindentation tests), optimizing the mechanical and shrinkage properties of the mortar. BP modified with 0.1% TA showed a 26.32% increase in compressive strength and a 15.64% increase in flexural strength at 28 days, with a 25.08% reduction in shrinkage after 90 days. These findings provide a possibility for the preparation of excellent performance of BP concrete and realize the efficient application of BP.

Microscopic visualization of heterogeneous condensation of water vapor on hydrophilic and hydrophobic particles

Heterogeneous condensation of water vapor on particles is widely used in the fields of atmospheric cloud physics and industrial particulate abatement. Particles surface wettability plays a fundamental role in water vapor condensation, but a microscopic insight of the impact of particles surface wettability on vapor condensation is lacked. Therefore, the Environmental Scanning Electron Microscope (ESEM) is adopted to directly visualize vapor condensation on particles with different surface wettability at a microscopic scale. Firstly heterogeneous condensation of water vapor on the hydrophilic and hydrophobic particles is obtained by the ESEM. The results show that when water vapor condenses on the hydrophilic particles, a spherical cap-shaped embryo first appears and subsequently develops into a spherical droplet to finally wrap the single particle. While on the hydrophobic particles, a spherical cap-shaped embryo will first appear and continue to grow into a spherical droplet to finally detach from the particle. Then the wetting coefficient is introduced to characterize the wetting degree of the droplet on the particle. The wetting coefficient will increase with the decrease of the contact angle, so the wettability of water vapor on the hydrophilic particles is better than that on the hydrophobic particles. Meanwhile based on classical nucleation theory, the geometrical factor and the critical supersaturation will decrease when the contact angle decreases, making it easier for water vapor to condense on the hydrophilic particles. Finally the line tension is investigated to explain the condensation mechanism. On the hydrophilic particles, when the droplet has crossed the equatorial line of the particle, the positive line tension promotes the spreading movement of the droplet over the particle to form a wrapped spherical droplet. Therefore, there is a transition from a spherical cap-shaped embryo before crossing the equatorial line of the particle to a wrapped spherical droplet after crossing the equatorial line. While on the hydrophobic particles, the negative line tension suppresses the spreading movement of the droplet over the particle to form a detached spherical droplet. So there is a transition from a spherical cap-shaped embryo before crossing the equatorial line of the particle to a detached spherical droplet after crossing the equatorial line.

Investigation of the mechanical work during ultrasonic fatigue loading using pulsed time-resolved X-ray diffraction.

In the energy production and transportation industries, numerous metallic structures may be subjected to at least several billions of cycles, i.e. loaded in the very high cycle fatigue domain (VHCF). Therefore, to design structures in the VHCF domain, a reliable methodology is necessary. One useful quantity to characterize plastic activity at the microscopic scale and fatigue damage evolution is the mechanical work supplied to a material. However, the estimation of this mechanical work in a metal during ultrasonic fatigue tests remains challenging. This paper aims to present an innovative methodology to quantify this. An experimental procedure was developed to estimate the mechanical work from stress and total strain evolution measurements during one loading cycle with a time accuracy of about 50 ns. This was achieved by conducting time-resolved X-ray diffraction coupled to strain gauge measurements at a synchrotron facility working in pulsed mode (single-bunch mode).

Ordered patterns in electroactive polymer ionic liquid blends: effect of long range interactions.

Designing multifunctional soft materials via pattern formation has been a major challenge for scientists and engineers. Soft materials based on polymers are the perfect candidates for designing such materials as they are not only easy to handle, but also offer diverse combinations of mechanical and chemical properties. Here, we present a polymer-based ternary system and reveal, using modelling and simulations, the mechanisms for creating patterned surfaces. Specifically, we consider polymer ionic liquid (PIL) blends and demonstrate that exposure to a uniform electric field results in the formation of ordered patterns through phase separation. Our approach is based on reaction-diffusion phenomena and utilizes Poisson-Boltzmann-Nernst-Planck equations to capture the long-range interactions of ionic liquids in both weak and strong segregation limits. Furthermore, we elucidate that the ordered patterns in our PIL blend can be tuned by changing the direction of the electric field. From the structural characterization point of view, we reveal that the presence of the electric field significantly enhances the domain growth rate and their respective ordering in a remarkable fashion. We believe this non-invasive technique is a significant step towards the development of ordered structures at microscopic length scales and can be utilized for micro-scale fabrication from soft materials.

Multiscale organisation of lead carboxylates in artistic oil binders.

The supramolecular and mesoscopic architectures of lead-saponified linseed oil, used by painters since the Renaissance, have been characterised and linked to their rheological properties. The multi-scale organization of saponified oils has been demonstrated by SAXS (Small Angle X-ray Scattering), FF-TEM (Freeze-Fracture Transmission Electron Microscopy) and DIC (Differential Interference Contrast): some of the lead soaps (formed when the oil is heated in the presence of PbO) are organized into microscopic lamellar domains, distributed in a continuous matrix made up of unorganized species (partially saponified triglycerides, glycerol, remaining soaps, etc.). The concentration of lead soaps in the oil controls the average size and interaction between the lamellar domains. Linseed oil + PbO 17 mol% is viscous and consists of aggregates of lamellar domains isolated within the continuous unorganized matrix. In contrast, in linseed oil + PbO 50 mol%, the domains are homogeneously dispersed and form what can be described as a three-dimensional network, giving the system viscoelastic properties.

Colloidal 2D Mo1-xWxS2 nanosheets: an atomic- to ensemble-level spectroscopic study.

Composition dependent tuning of electronic and optical properties in semiconducting two-dimensional (2D) transition metal dichalcogenide (TMDC) alloys is promising for tailoring the materials for optoelectronics. Here, we report a solution-based synthesis suitable to obtain predominantly monolayered 2D semiconducting Mo1-xWxS2 nanosheets (NSs) with controlled composition as substrate-free colloidal inks. Atomic-level structural analysis by high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDXS) depicts the distribution of individual atoms within the Mo1-xWxS2 NSs and reveals the tendency for domain formation, especially at low molar tungsten fractions. These domains cause a broadening in the associated ensemble-level Raman spectra, confirming the extrapolation of the structural information from the microscopic scale to the properties of the entire sample. A characterization of the Mo1-xWxS2 NSs by steady-state optical spectroscopy shows that a band gap tuning in the range of 1.89-2.02 eV (614-655 nm) and a spin-orbit coupling-related exciton splitting of 0.16-0.38 eV can be achieved, which renders colloidal methods viable for upscaling low cost synthetic approaches toward application-taylored colloidal TMDCs.

Experimental Study of the Physical and Mechanical Properties of Cement‐Based Composite Reinforced With Macro‐/Microfibers: Case of Rhecktophyllum camerunense and Triumfetta pentandra

Plant fibers have the ability to bridge crack propagation on a microscopic scale for microfibers and on a macroscopic scale for macrofibers. Therefore, the use of two or more fiber types in an appropriate combination can potentially improve the overall properties of the cement composite as well as promote green construction. The hybrid composite was cast using random orientation with two fibers: Rhecktophyllum camerunense as macrofiber and Triumfetta pentandra as microfiber. Cement mortar matrices were reinforced with a constant microfiber length of 1 mm and three different macrofiber lengths of 1.5, 3, and 6 mm at varying fiber contents of 1%, 1.5%, and 2.5% wt. The physical characteristics of the composite were assessed by porosity, density, and water absorption. Mechanically, three‐point bending tests and single‐edge notch bending (SENB) tests were performed after 7 and 14 days of curing. Mode I fracture behavior (KIC) and modulus of rupture (MOR) were calculated as per formulation. Physical experimental results reveal that there is a correlation between the rate of water absorption, porosity, density, and that of the fiber loading and length in the composite. Mechanically, the developed material presented a multiple cracking behavior under bending. There was a decrease in MOR and fracture toughness values with a decrease in macrofiber content in the hybrid composite. They both presented an increase in value with an increase in fiber content and fiber length. The composites reinforced with both fibers presented higher values of MOR than the unreinforced due to the powerful interfacial bond between the fibers and the cement matrix. The unreinforced composites had the least MOR and fracture toughness values of 0.442 MPa and 694,000 N.m1.5, respectively, showing that they are very reactive to faults at low stress levels.

Heat accumulation and phase transition induction in a VO2 thin film by a femtosecond pulse-periodic radiation.

The kinetics of optical switching due to the insulator-metal phase transition in a VO2 thin film is studied experimentally at different laser pulse repetition frequencies (PRFs) in the NIR range and compared with temperature kinetics obtained through the thermal conductance calculations. Two switching processes have been found with characteristic times <2 ms and <15 ms depending on the PRF; the former is explained by the accumulation of metallic domains remaining after a single-pulse phase transition, and the latter is referred to the heat accumulation in the film. Consequently, the dynamics of the microscopic domains is leading in the initiation of phase transition under pulse-periodic conditions compared to the macroscopic heat transfer. The reverse transition at the radiation turn-off depends on the PRF with a time coefficient of 17.5 µs/kHz and is determined by the metallic domains' decay in the film. The results are important for understanding the nature of the insulator-metal transition in thin films of VO2 as well as using them in all-optical switches of pulse-periodic laser radiation.

Experimental investigation on the ballistic performance of B4C/Aramid/UHMWPE composite armors against API projectile under different temperatures

In the design of lightweight composite armor, it is crucial to consider the challenging conditions of extreme environments encountered during service. This study proposes to investigate the effect of temperature on the ballistic performance of a B4C/aramid III/UHMWPE composite armor system against 12.7 mm armor-piercing incendiary (API) projectiles with an impact velocity of ∼500 m/s. A series of ballistic experiments were conducted under low temperature (-40 ℃), high temperature (+70 ℃), and room temperature (+20 ℃) respectively considering two shooting distances of 100 m (long-range shooting) and 30 m (close-range shooting). The structural failure modes and associated mechanisms were identified and analyzed in detail from both macroscopic and microscopic scales. The experimental results indicate that the designed composite armor is believed to perform better than the existing design schemes in resisting the 12.7 mm half-speed API projectile on the basis of similar or less areal density. The ballistic performance of the composite armor system is significantly enhanced at low temperatures and weakened at high temperatures in terms of structural damage levels and backplate bulge deformation. The decrease in shooting distance transformed the panel failure mode essentially from non-penetration to penetration under room and high temperatures, whereas the specimens under low temperatures could prevent penetration. Both the ceramic and composite laminate materials are affected by temperature and show different microscopic damage modes, indicating the damage mechanism changes at the microscopic level. These findings provide valuable insight into the design of lightweight composite armor systems to adapt to extreme service environments.