Materials Research Express

Quantum dots (QDs) have sparked great interest due to their unique electronic, optical, and structural properties. In this review, we provide a critical analysis of the latest advances in the synthesis, properties, and applications of QDs. We discuss synthesis techniques, including colloidal and hydrothermal synthesis, and highlight how the underlying principles of these techniques affect the resulting properties of QDs. We then delve into the wide range of applications of QDs, from QDs based color conversion, light-emitting diodes and biomedicine to quantum-based cryptography and spintronics. Finally, we identify the current challenges and future prospects for quantum dot research. By reading this review, readers will gain a deeper understanding of the current state-of-the-art in QDs research and the potential for future development.

Hydrogel is being broadly studied due to their tremendous properties, such as swelling behavior and biocompatibility. Numerous review articles have discussed hydrogel polymer types, hydrogel synthesis methods, hydrogel properties, and hydrogel applications. Hydrogel can be synthesized by physical and chemical cross-linking methods. One type of the physical cross-linking method is freeze-thaw (F–T), which works based on the crystallization process of the precursor solution to form a physical cross-link. To date, there has been no review paper which discusses the F–T technique specifically and comprehensively. Most of the previous review articles that exposed the hydrogel synthesis method usually mentioned the F–T process as a small part of the physical cross-linking method. This review attempts to discuss the F–T hydrogel specifically and comprehensively. In more detail, this review covers the basic principles of hydrogel formation in an F–T way, the parameters that influence hydrogel formation, the properties of the hydrogel, and its application in the biomedical field.

In the present review, the effect of porosity on the mechanical properties of the fabricated parts, which are additively manufactured by powder bed fusion and filament extrusion-based technologies, are discussed in detail. Usually, additive manufacturing (AM) processes based on these techniques produce the components with a significant amount of pores. The porosity in these parts typically takes two forms: pores with irregular shapes (called keyholes) and uniform (spherical) pores. These pores are present at different locations, such as surface, sub-surface, interior bulk material, between the deposited layers and at filler/matrix interface, which critically affect the corrosion resistance, fatigue strength, stiffness, mechanical strength, and fracture toughness properties, respectively. Therefore, it is essential to study and understand the influence of pores on the mechanical properties of AM fabricated parts. The technologies of AM can be employed in the manufacturing of components with the desired porous structure through the topology optimization process of scaffolds and lattices to improve their toughness under a specific load. The undesirable effect of pores can be eliminated by using defects-free raw materials, optimizing the processing parameters, and implementing suitable post-processing treatment. The current review grants a more comprehensive understanding of the effect of porous defects on mechanical performance and provides a mechanistic basis for reliable applications of additively manufactured components.

Additive manufacturing, a cutting-edge technology often colloquially known as 3D printing, is a transformative process used to meticulously fabricate complex components by adding material layer upon layer. This revolutionary manufacturing method allows for precise control and customization, making it a go-to choice in various industries, from aerospace to healthcare. The adroitness of additive manufacturing in creating a complex geometry as a whole is very much harnessed by the aerospace Industry. Generating a component using additive manufacturing involves optimal design, methods, and processes. This review gives a broad knowledge in developing a part or product by choosing the appropriate design, method, and processes. The end-to-end flow process (from scratch to finished model) for developing a component by additive manufacturing is described with a detailed flow diagram. The flow process proposed in this review will act as a primary source for manufacturing any component as per the industry standards. Also, the role of additive manufacturing in the aerospace industry is the need of the hour and greatly in demand of innovative ideas. But as an infant technology, AM for aerospace has its fair share of issues The paper discusses issues and challenges of AM for aerospace applications to enable the widespread adoption of additively manufactured components in the aerospace industry.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted extensive attraction due to their unique properties in novel physical phenomena, such as superconductors, Moiré superlattices, ferromagnetics, Weyl semimetals, which all require the high quality of 2D TMDs. Mechanical exfoliation (ME) as a top-down strategy shows great potential to obtain 2D TMDs with high quality and large scale. This paper reviews the theoretical and experimental details of this method. Subsequently, diverse modified ME methods are introduced. Significantly, the recent progress of the Au-assisted ME method is the highlight. Finally, this review will have an insight into their advantages and limitations, and point out a rational direction for the exfoliation of TMDs with high quality and large size.

The oxidation behavior of 316L stainless steel exposed at 400, 600 and 800 °C air for 100, 500 and 1000 h was investigated using different characterization techniques. Weight gain obeys a parabolic law, but the degree of deviation of n index is increasingly larger with the increase of temperature. A double oxide film, including Cr₂O₃ and Fe₂O₃ oxide particles in outer and FeCr₂O₄ oxides in inner, is observed at 400 °C. As regards to samples at 600 °C, a critical exposure period around 100 h exists in the oxidation process, at which a compact oxide film decorated with oxide particles transforms to a loose oxide layer with a pore-structure. In addition, an oxide film containing Fe-rich outer oxide layer and Cr-rich inner oxide layer is observed at 600 °C for 500 and 1000 h. Spallation of oxide scale is observed for all samples at 800 °C regardless of exposure periods, resulting in different oxidation morphologies, and the degree of spallation behavior is getting worse. A double oxide film with the same chemical composition as 600 °C is observed, and the thickness increases over exposure periods.

Additive manufacturing facilitates the creation of complex porous metallic structures with significant mechanical strength, suitable for tailored, lightweight product requirements in the aerospace and automotive industry. Among these, diamond metal lattice structures (DLS) stand out due to their high porosity. This study investigates the mechanical performance of SS 316L diamond lattice structures fabricated using selective laser melting (SLM), with and without nodal reinforcement. The effect of nodal reinforcement and variations in strut and node dimensions was analysed under quasi-static compression. Node-reinforced diamond lattice structures (NR-DLS) exhibited superior mechanical properties to non-reinforced DLS. Results demonstrated that increasing node and strut sizes enhanced yield strength, collapse strength, and energy absorption while reducing porosity. Statistical analysis using ANOVA and Tukey's HSD confirmed the significant effect of nodal reinforcement, particularly when strut and node sizes were proportionally increased. Additionally, NR-DLS showed improved stress distribution, leading to uniform densification.

Cobalt oxide nanoparticles (Co₃O₄-Nps) have many applications and now a days the green methods of synthesis of these NPs are preferred over other methods because of associated benefits. In this study, Co₃O₄-Nps were synthesized by using leaves extract of Populus ciliata (safaida) and cobalt nitrate hexa hydrate as a source of cobalt. The synthesized NPs were analyzed by different techniques such as fourier transform spectroscopy (FTIR), x-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Antibacterial activities of the synthesized Co₃O₄-Nps were evaluated against gram negative and gram positive bacteria and found active against Escherichia coli (E. coli), Klebseilla pneumonia (K. pneumonia), Bacillus subtillus (B.subtillus) and Bacillus lichenifermia (B. lichenifermia). The activity results were analyzed statistically by one-way ANOVA, with 'Dunnett's Multiple Comparison Test'. The maximum mean activity (21.8 ± 0.7) was found for B. subtilis and minimum mean activity (14.0 ± 0.6) was observed for E. coli.

In this work, we use dyadic Green's functions to calculate local density of states in a finite-size one-dimensional photonic crystal surrounded by air. The crystal composes alternating layers of polymer materials, with its translational periodicity disrupted by the introduction of a cavity. Its optical properties are affected by variations in the polymers' dielectric constant under applied pressure, and the cavity is infiltrated with four types of cells: Normal, Jurkat, PC12, and MCF-7. Our findings reveal that, within the photonic band gaps, the local density of states reaches a maximum, a characteristic of localized modes. We show that when the dielectric constant of each cell type is increased, the localized mode shifts to shorter frequencies, exhibiting a specific value for the local density of states. Furthermore, we report that the localized mode shifts to higher frequencies when pressure increases while reducing the local density of states.

This study employed a hot-rolling technique to fabricate a bimetal composite combining Hadfield steel and High-chromium cast iron (HCCI). The microstructure evolution and tensile properties of the bimetal composite were studied. Experimental results revealed that initial HCCI layers, characterized by limited plasticity, underwent necking and fragmentation into irregular fragments during deformation. The bonding interface of the two metals presented a wave shape. The two metals fused together and showed a good metallurgical bonding without interface cracks and delamination. The composite demonstrated an average tensile strength of 284 MPa. The results of tensile test showed that a large number of tunnel cracks were formed near the fracture of the sample. In the bimetallic composite, crack propagation stopped or transferred when encountering ductile Hadfield steel.

Lignin, as the world's second-largest biomass resource, has a low utilization rate. Converting lignin into high-value chemicals can not only alleviate the shortage of fossil fuels but also reduce environmental pollution caused by indiscriminate accumulation and combustion. In this study, a method for preparing phenolic compounds by depolymerization of calcium lignosulfonate (CLS) catalyzed by solid base oxides was proposed. MgO, NiO, Fe₂O₃, binary metal oxides (MgFeO_x and NiFeO_x), and ternary metal oxide (NiMgFeO_x) were synthesized. MgO, NiO, and Fe₂O₃ exhibit pure and regular structures. The binary and ternary metal oxides synthesized using hydrotalcites as precursors exhibit layered morphologies and process distinct primary and secondary phases. The alkalinity of oxides can be adjusted through the synergistic effect of Ni, Mg, and Fe. Under the catalytic action of metal oxides, the selectivity of hydrocarbons in gaseous products increases, along with the yield of liquid products. The presence of multiple metal elements enhances catalytic performance, indicating the synergistic effects among metal elements. NiMgFeO_x demonstrates the highest catalytic efficiency, achieving a liquid product yield of 75.8 wt% and a total phenolic compound selectivity of 78.6%. After five cycles of catalytic regeneration, NiMgFeO_x maintains its satisfactory structure and catalytic stability. This study provides both theoretical and experimental insights into CLS depolymerization catalyzed by solid base oxides.

In the past few years, significant advancements have been made in soft robotics using various actuators. One notable development is the emergence of Twisted and Coiled Polymers (TCP) and the integration of TCP actuators in silicone. TCP artificial muscles have several advantages: they are quiet, inexpensive, exhibit low hysteresis, operate at low voltage and can be tailored for desired shapes. This research focuses on characterization of the 2-ply TCP actuators embedded in silicone and their application for a swimming robot and grasping application. Initially, the actuators were characterized for static and dynamic behaviors, considering critical parameters such as applied voltage, actuation frequency, pre-tension, resistance of the muscles, geometry and the material composition. Out of these, the first three parameters can be controlled during operation. The study determined the optimum ranges for these controllable parameters, specifically for a swimming and grasping applications. For swimming, a low-profile robotic structure with four limbs (each measuring 140 × 60 × 5 mm³) was developed that was able to swim a vertical displacement of 343 mm in 640 s. Limb actuation conditions were also optimized for grasping, demonstrating successful grasping in air and in water against gravity using a single or combined limbs. The 2-ply TCP actuators provided a strain of 12.5% at a 300 g (2.9 N) optimum load and a blocking force of 1.7 kg (16.7 N) when supplied with 225 J of electrical input energy (20 V, 0.75 A current and 15 s heating time). Notably, this soft structure with embedded TCP actuators has not been demonstrated in an underwater environment, and hence this study adds new knowledge in this area. Furthermore, FEM simulation results on a single limb under the effect of gravity was performed using ANSYS to compare with experimental results. This research has potential applications in underwater exploration and manipulation in hazardous environments.

Natural fiber-reinforced composites have gained significant attention due to their environmental benefits and desirable mechanical properties, including inherently beneficial vibration damping and acoustic characteristics. In this study, untreated, Alkali, Silane and Permanganate-treated Helicteres isora fiber-reinforced Polylactic acid composites were assessed to determine the effect of fiber treatment on the vibration and acoustic behaviour of the composites. Vibrational analysis was conducted to identify natural frequencies and damping ratios of the composites. The results demonstrated that alkali-treated fiber composite significantly enhanced the vibrational properties of the composites, with a 30% increase in damping ratio compared to untreated fiber composites. Acoustic transmission loss (TL) was measured to assess their suitability as soundproofing material using the impedance tube method. The results showed that silane-treated composites offered the highest TL in the frequency range 4000 to 6300 Hz, 35% more than untreated fiber composites, indicating their potential as an effective material in applications requiring soundproofing. In contrast, untreated fibers provided the lowest TL, affirming the impact of fiber modifications on acoustic performance. This study demonstrates that fiber modifications play a significant role in optimizing the vibrational and acoustic behaviour of natural fiber-reinforced bio-composites, making them a viable alternative for lightweight structural and noise-reducing applications.

This study focuses on the synthesis of superabsorbent polymers (SAPs) from jackfruit seed starch and acrylic monomers using the frontal polymerization (FP) method. Acrylic acid (AA) and acrylamide (AM) were grafted onto jackfruit seed starch with varying initiator contents (0.5, 0.75, 1, and 1.5 wt%) in the presence of MBA as a cross-linker (0.1 wt% relative to AA) to produce SAPs. The effect of external heat source temperature was also investigated. Using an external heat source at 1200 °C and a PPS initiator content of 1% resulted in SAPs JFSS-g-AA and JFSS-g-AM with water absorption capacities (WAC) of 415 g g⁻¹ and 298 g g⁻¹, respectively. In comparison, the conventional method yielded WACs of 364 g g⁻¹ and 273 g g⁻¹ for the same polymers. The synthesized polymers were characterized using FTIR, SEM, TGA, and XRD. The grafted polymers exhibited superior properties, including shorter reaction times and lower costs than conventional methods, as FP requires only an initial energy input to initiate polymerization, with no further energy needed. FP samples achieved reaction times of 19–21 min, significantly shorter than those of conventional samples (49 and 46 min, respectively). An increase in the external heat source temperature raised the front temperature, with a recorded peak of 126 °C. The frontal velocity was proportional to the initiator content, influencing the propagation of the reaction front. Compared to conventional polymerization, FP produced polymers with higher absorption capacity. These findings suggest that FP is a cost-effective and time-efficient alternative for synthesizing graft polymers from acrylic monomers and starch.

The high hardness performance of Fe-based amorphous alloys give them unique advantages in the field of wear-resistant materials, while the performance degradation after crystallization limits their application range. In this study, rod-shaped bulk Fe₄₁ amorphous alloy was prepared, and its crystallization characteristics were studied in response to its high temperature conditions in wear service environment. Aging treatments were carried out on the materials at different temperatures, and the characteristics and mechanism of amorphous alloy crystallization transformation were analyzed. The research results indicate that the crystallization rate of Fe₄₁ bulk amorphous alloy exhibits a bilinear characteristic with increasing temperature, and the transformation temperature at which crystallization significantly accelerates is between 180 °C and 250 °C. The main reason for the surface crystallization of Fe₄₁ bulk amorphous alloy is the local stress release caused by the detachment of the second phase under aging temperature conditions. For the interior of the material, structural constraints effectively suppress crystallization transformation within 350 °C.

This overview details the characteristics and attributes of hot-deformed Duplex Stainless Steel (DSS) 2205, emphasizing its phases, alloying elements, and deformation behaviour. Due to its exceptional mix of mechanical qualities and corrosion resistance, it has found extensive applications in water treatment and desalination, chemical industries, oil and gas storage tankers, construction, food production, and marine environments. Its properties during hot deformation are crucial in defining its applications. DSS 2205 features a balanced dual-phase microstructure, with ferrite (α) and austenite (γ) phases in roughly equal quantities, resulting in high mechanical characteristics and corrosion resistance. Depending on the alloy composition and processing conditions, hot deformation can result in the development of secondary phases. Temperature, strain rate, and initial microstructure impact DSS 2205's hot deformation. Hot deformation initiates several forms of grain boundaries, which contribute to microstructural evolution and yielding properties. Therefore, the characteristics of hot-deformed DSS 2205 show a refined and dynamically recrystallized microstructure, resulting in improved properties. Understanding the interaction of alloying components, phases, and deformation conditions can help optimize the hot deformation process for DSS 2205. In conclusion, this study emphasizes optimizing the phases and deformation parameters to fully utilize DSS 2205 in demanding applications.

With the increasing demand for sustainable energy solutions, laser surface modification has emerged as a promising technique to enhance the functional properties of materials, particularly in optimizing glass surfaces for solar applications that require hydrophobicity and environmental resilience to improve photovoltaic performance and durability. Consequently, a SWOT-TWOS analysis is conducted to identify the strengths, weaknesses, opportunities, and threats of integrating these technologies. This analysis assesses the advantages, such as improved light diffusion and reduced glare, along with the disadvantages, including decreased transparency and potential glass damage. Additionally, there are opportunities for technological and sustainable advancements, as well as threats such as quality control issues. The SWOT analysis for Laser Treated Super Hydrophobic Glass in solar PV self-cleaning applications revealed a distribution of 42% technical, 26% environmental, and 21% economic factors, with 11% of factors spanning all three domains. Notably, the two elements are complex and interdependent across multiple domains, underscoring the intricate influences affecting the viability of this technology. By identifying these characteristics, the study aims to provide a comprehensive understanding of laser texturing potential and limitations, as well as recommendations for future research and practical applications.

Bamboo fiber-reinforced composites have emerged as environmentally friendly, plentiful, and high-mechanical-performance materials used in recent years. This review presents an overview of the mechanical and water uptake properties of bamboo fiber polymer composites and bamboo/glass fiber/nanoclay hybrid composites to consider their structural and industrial applications. Bamboo fibers have better mechanical properties compared to polymers. Moisture absorption and fiber surface treatments influence their long-term functionality. Hybrid composites of bamboo, glass fibers, and nanoclay have revealed synergistic mechanical and water uptake properties. Adding nanoclay enhances interfacial adhesion and prevents void formation, improving overall mechanical performance. This review also discusses the impact of hybridization ratios and fiber surface treatments on bamboo fiber composite behavior. The results suggest that, whereas bamboo fiber polymer composites are suitable for applications requiring lightweight composites, hybrid composites exhibit better mechanical properties to be used in advanced engineering applications. Future research topics will include the optimization of hybrid compositions and sustainable treatment strategies to enhance the performance and longevity of these composites further.

As the world moves toward greener energy generation methods and cleaner environments, activated carbon produced from ligninocellulosic resources has attracted unexpected interest due to its easy availability, and economic, renewable, and biodegradable properties, which makes it a viable alternative to exhaustible coal. This review paper provides a comprehensive overview of a systematic procedure to develop activated carbon from plant biomass, its characterization by simple techniques, and the versatile applications of activated carbon. This includes its role in environmental remediation, from emphasizing its efficacy in removing a wide array of pollutants, to sustainable methods of hydrogen capture and energy storage in supercapacitors. A brief comparison of the key aspects of optimal toxicant adsorption, like batch conditions, the best-fit model, isotherms, and maximum adsorption, are also made. To ascertain the efficiency of the supercapacitors, their strategy in designing it, and their output in terms of specific capacitance, power, and energy density are compared.

This paper studies the role of reversed austenite in martensitic stainless steels, summarizes the formation principles of reversed austenite in martensitic stainless steels and reviews elements influencing its formation. It also summarizes common heat treatment methods for obtaining reversed austenite in martensitic stainless steels and compares the advantages and disadvantages of various approaches. For example, layered quenching and tempering yield more reversed austenite compared to simple tempering, resulting in finer microstructures at room temperature. The paper analyzes how different reversed austenite contents affect the strength, ductility, and hardness of martensitic stainless steels, as well as the impact on pitting, intergranular, hydrogen, and stress corrosion. It finds that a higher amount of reversed austenite leads to a higher yield-to-tensile strength ratio, increased ductility, and lower hardness. While reversed austenite improves resistance to pitting, intergranular, and stress corrosion, its effect on hydrogen embrittlement remains debated. Additionally, the paper summarizes the formation principles of reversed austenite in martensitic stainless steels and reviews elements influencing its formation, aiming to identify optimal elements and heat treatment methods to increase reversed austenite content. This paper aims to make a summary of the research of experts and scholars in recent years, provide the knowledge foundation for the scholars who have just contacted, and give some reference for the future research direction.

Fiber metal laminates (FMLs), which fuse the strengths of alloys and fiber-reinforced composites, find application in the aerospace and automobile sectors. Despite the benefits, functional performance depends on the quality of the bonding strength at the metal-composite interface. Therefore, in the present study, effect of mechanical abrasion (MA), nitric acid etching (NI), P2 etching (P2), sulfuric acid anodizing (SA), and electric discharge texturing (ED) surface treatments methods was evaluated by considering the surface morphology, roughness, wettability, and surface energy. Furthermore, the impact of surface treatment methods on the tensile and flexural behavior of Carbon Reinforced Aluminum Laminate (CARALL) fabricated using the treated aluminum substrate was studied and compared with untreated laminates. The results showed that all treatment methods increased the surface roughness of the aluminum substrate. MA and ED treatments imparted higher surface roughness (0.95 and 1.85 µm), with the surface displaying hydrophobic behavior, while chemical and SA treatments increased the surface energy (39.1 MJ/m2, 45.2 MJ/m2, and 60.1 MJ/m2) and produced surfaces exhibiting hydrophilic behavior. Surface treatments helped improve the ultimate tensile strength of CARALL laminates. The highest improvement, 61%, was achieved using SA treatment (921.43 MPa), while MA resulted in a modest 38% improvement (789.82 MPa). SA treatment increased the elastic modulus and toughness by 188% and 82% in comparison to the untreated specimens. A similar increase in flexural strength was noted, with a 35% increase in the case of MA and a maximum 104% increment from SA, as against untreated ones. Flexural modulus and toughness of 88.05 GPa and 32.39 MJ/m3 was attained with the help of SA treatment. Delamination was observed during the plastic deformation stage under the tensile loading conditions. However, delamination occurred during the end stages of failure under flexural loading, indicating a higher delamination resistance offering by CARALL with flexural loading conditions.

Peridynamics theory has become a popular approach for analyzing fracture damage in fiber-reinforced composite laminates because it uses integral equations to describe the mechanical behavior among internal material points. However, simulating fracture damage with bond-based peridynamics is challenging when incompressible components are present. To address this issue, this paper proposes an improved model based on non-ordinary state-based peridynamics theory. In this model, tensor forms are used to describe the interactions between material points in fiber-reinforced composites, and the Hoffman strength criterion is introduced to capture the different responses under tensile and compressive loading. Moreover, the OpenMP approach is employed to accelerate the simulation process. The model is validated through a displacement load simulation on a composite laminate under displacement load, and the displacement results agreed well with those obtained from the finite element method, with a displacement error at the midline of 0.73%. Additionally, analyses of composite laminates with defects and real material tensile experiments further verify the detailed processes of damage initiation, propagation, and crack growth. The proposed method provides a mesh-free, efficient tool for dynamic fracture analysis in composite materials, with significant potential for applications in aerospace and marine engineering.

With the development of globalization, civil aviation plays an increasingly important role in various types of transportation methods. As airports are vital hubs for civil aviation, their renovation and expansion will significantly affect the operational efficiency and security of civil aviation. The traditional airport construction method requires the interruption of airport operations, which has a great negative impact on the continuous operation of air transportation. Non-suspending construction can ensure that renovation, expansion and routine structural safety detections are conducted without interrupting the orderly operation of the airports, which greatly improves the operational efficiency and security of airport operations. As a kind of advanced construction material, rapid-setting materials mainly include rapid-setting cement and rapid-setting asphalt, which are characterized by the advantages of shortened setting time, high early strength, low life-cycle cost and accelerated construction progress. In the early stages, rapid-setting materials were used for road pavement repair. In recent years, rapid-setting materials have also been broadly used in non-suspending airport construction. The application of rapid-setting materials in non-suspending airport construction can further shorten the duration of construction, improve the efficiency of airport renovation and expansion, and ensure the continuous operation and security of the airport. Therefore, this paper systematically reviews the application of rapid-setting materials in non-suspending airport construction from three aspects, which are material properties, functioning mechanisms and case studies, then the main challenges encountered at this stage are summarized, and future development prospects are also outlooked. Thus, this review is expected to provide new design methods for modern, intelligent and efficient airport construction.

Conventional methods for preparing activated carbon with excellent electrical double-layer capacitor (EDLC) performance result in low yields and high costs due to the need for a large-surface-area structure. The creation of micropores increases the surface area of activated carbon but requires gasification of the carbonaceous component of the raw material, which is a challenging process. In this study, the addition of melamine sulfate to the cellulose precursor increased the yield from 10.8% to 24.4%, whereas the addition of guanine sulfate increased the yield to 18.4%. The mesopore-to-total pore volume ratio varied from 9.7% to 60.7% with the addition of melamine sulfate or guanine sulfate; this ratio was controlled by adjusting the addition amounts and the thermal pre-treatment conditions. The activated carbon samples were subsequently used as electrodes in EDLCs, and their charge/discharge properties were evaluated. The specific capacitances of the active materials prepared with melamine sulfate reached ~30 F g⁻¹ at a current density of 0.5 A g⁻¹, which was approximately three times higher than those of other samples. Specific capacitance improved after nitrogen doping and after the mesopore proportion had been increased to 60.7%. Impedance spectroscopy indicated that the increased mesopore proportion facilitated ion migration into the pores. The proposed method provides a simple and effective means of producing mesoporous carbon with up to 60.7% mesopores and desirable electrochemical properties, achieving low internal resistance.

Aerosol particles play a vital role in air quality monitoring, climate change, and human health. The collection and characterization of aerosol particles are essential for analysing their physical and chemical properties, which serve as key indicators. This review discusses both traditional aerosol collection techniques, such as electrostatic precipitation and filtration, and newer methods like liquid impingers, centrifugation and acoustic collection, each optimized for different particle sizes. It also covers advanced characterization techniques, including laser light scattering, laser-induced breakdown spectroscopy, light detection and ranging, infrared spectroscopy, and optical tweezers, which provide high-precision data on aerosol particle size, composition, and optical properties. These techniques have become indispensable for advancing aerosol research and environmental monitoring. The review highlights the advantages and limitations of various methods and discusses the ongoing technological advancements and integrated solutions that combine multiple collection and characterization approaches. Finally, it provides insights into the future directions and challenges in aerosol research and its applications.