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The study of pore characteristics in tectonic coal is essential for a deeper understanding of gas diffusion, seepage, and other transport processes within coal seams, and plays a crucial role in the development of coalbed methane resources. Based on low-temperature N2 and CO2 adsorption experiments, this study investigated the pore structure characteristics of four tectonic coal samples collected from the Hegang and Jixi basins in China. The results show that the mylonitic coal sample exhibits a clear capillary condensation and evaporation phenomenon around a relative pressure (P/P0) of 0.5. The degree of tectonic deformation in coal has a significant impact on its pore characteristics. As the degree of deformation increases, both the pore volume and specific surface area of the coal gradually increase. The pore volume and specific surface area of micropores are primarily concentrated in pores with diameters of 0.5–0.7 nm and 0.8–0.9 nm, while those of mesopores are mainly distributed in pores with diameters of 2.3–6.2 nm. The proportion of pore volume and specific surface area contributed by micropores is much greater than that of mesopores. The fractal dimension is positively correlated with the degree of tectonic deformation in coal. As the fractal dimension increases, the average pore diameter decreases, closely tied to the destruction and reconstruction of the coal's pore structure under tectonic stress. These findings will contribute to a deeper understanding of the pore structure characteristics of tectonic coal and effectively advance coalbed methane development. [ABSTRACT FROM AUTHOR]

The mechanical properties of High-Performance Self-Compacting Concrete (HPSCC) are strongly influenced by its pore structure, but the impact of varying water–binder ratios (W/C) on this relationship remains unclear. To address this, the present study investigates HPSCC with W/C ratios ranging from 0.19 to 0.23, aiming to elucidate the connection between pore structure, fractal characteristics, and mechanical performance. Through a combination of compressive strength testing, low-temperature nitrogen adsorption, and Scanning Electron Microscopy (SEM) observations, this study reveals key insights. First, compressive strength initially increases with a decreasing W/C ratio but plateaus beyond W/C = 0.21, identifying an optimal range for balancing strength and workability. Second, the pore structure of HPSCC is characterized by cylindrical, ink-bottle, and planar interstitial pores, with significant fractal characteristics. Notably, the fractal dimension decreases as the W/C ratio increases, indicating reduced pore complexity and improved homogeneity. Finally, a strong linear correlation (R2 > 0.9) between the W/C ratio, fractal dimension, and compressive strength provides a predictive tool for assessing HPSCC performance. This study concludes that the internal pore structure is a critical determinant of HPSCC strength, and the identified optimal W/C ratio range offers guidance for mixture designs. Additionally, fractal dimension analysis emerges as a novel method to evaluate HPSCC's microstructural quality, enabling predictions of long-term performance and durability. These findings contribute to the scientific basis for designing high-performance concrete materials with improved mechanical properties and durability. [ABSTRACT FROM AUTHOR]

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The creep rupture properties of DD419 single crystal superalloys，fabricated at varying pouring temperatures were examined under conditions of 850 ℃/650 MPa，1050 ℃/190 MPa and 1100 ℃/130 MPa. SEM，EDS and TEM were used to analyze the microstructure and component segregation to study their effects on the durability. The results show that as the pouring temperature decreases，the primary dendrite spacing of the alloy widens，the eutectic content and the number of micropore increase，and the γ′ phase size diminishes. Under high temperature/low stress（1100℃/130 MPa），the γ′ phase size exerts a more pronounced influence on durability than do micropore and residual eutectic content. The finely dispersed γ′ phase enhances the alloy’s durability under all three test scenarios，with the alloy poured at 1500 ℃ exhibiting optimal durability. At intermediate temperature/high stress condition（1050℃/190 MPa），the γ′ phase is intersected by numerous dislocations, and dispersed γ′ phase may contribute to dislocation pile-ups. Concurrently，the alloy maintains good elongation at different pouring temperatures；however，as the pouring temperature decreases，section shrinkage decreases under all three test conditions. Pouring temperature has a negligible impact on the the alloy’s fracture morphology. Specifically, the γ′ phase near the fracture surface of the specimen tested under 850 ℃/650 MPa condition remains cubic morphology，with a mixed -mode fracture mechanism. Under other durability parameters，the γ′ phase assumes a rafted configuration，leading to an all-micropore aggregation fracture mechanism.

The mechanism of bubble formation was revealed by recording pulsed laser welding with a high-speed camera and then observing the change of bubbles in the melt pool. The research shows thermal shock simultaneously produces two pressure waves and forms a negative pressure zone. When the pressure reaches a critical value, the negative pressure zone of the welding pool produces bubbles. The size of the bubble in the weld pool varies with the laser power. Some bubbles burst and disappeared, because the radius size reached the critical value, and some became pores after solidification in the molten pool. In addition, there are cavities inside the melt pool under the effect of thermal shock, and these cavities will become pores after the solidification of the melt pool. [ABSTRACT FROM AUTHOR]

When it comes to owning pets, pet odor is a major concern for many individuals. Ammonia (NH3) and hydrogen sulfide (H2S) are the primary odor components that have negative effects on human life. Therefore, there is an urgent need to develop a deodorizing material with high NH3 and H2S adsorption capacity. In this study, Resorcinol-formaldehyde (RF) aerogels containing amine groups (RF-Mx) were prepared using the sol-gel method and atmospheric pressure drying technique. Melamine was used as a modifier. The specific surface area of the modified aerogel was 119 m2/g with an average pore size of 12 nm when the melamine addition was 20%. The adsorption capacity of RF-M20 for odor was the highest (NH3: 593.8 mg/g, H2S: 640 mg/g), which was significantly superior to the unmodified sample. In addition, the adsorption capacity of RF-M20 for H2S exceeded that of commercial activated carbon. The results concluded that the introduction of amine groups and the higher microporous specific surface area benefited the chemical and physical adsorption of gases, effectively improving the adsorbent's capacity to capture NH3 and H2S. The preparation method is not only efficient in enhancing the odor adsorption capacity but also simple and cost-effective to operate, showing promising potential for industrial applications. [ABSTRACT FROM AUTHOR]

Because direct carbonation of asphalt usually yields ordered graphite structure with unfavorable storage of sodium. Here, the asphalt preoxidation at a specific temperature in the air introduces oxygen‐containing groups to connect the unsaturated aliphatic hydrocarbon and aromatic side chains, forming a disordered carbon skeleton to inhibit melting and rearrangement during carbonization. The abundant oxygen‐containing groups hinder the growth of the carbon layers during pyrolysis, which promotes the formation of disordered phases and abundant micropores in asphalt‐based hard carbons (HCs). The simultaneous increase in initial coulombic efficiency, capacity, and transport behavior of sodium ions in HCs is achieved by adjusting the carbon layer and micropore evolution. The optimized HCs display excellent initial coulombic efficiency of 86.14% with remarkable reversible capacity of 313.83 mAh g−1 at 0.1 C and high‐rate capability with 140 mAh g−1 at 5 C. Pairing with O3‐NaNi1/3Fe1/3Mn1/3O2 cathode, the full cell delivers a higher reversible capacity of 255.7 mAh g−1 with an initial coulombic efficiency of 83.7% and long cycle life. Based on the microstructure and electrochemical behaviors of asphalt‐based HCs, the “adsorption‐insertion‐pores‐filling” sodium storage mechanism is proposed, providing guidelines for designing high‐energy‐density sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Modification of local bamboo‐based catalytic activated carbon with metallic Ag can produce mesopore and micropore types, with a mesopore content of 86%. One of the best ways to reduce formaldehyde concentrations is through catalytic adsorption. In combination with Ag nanoparticle catalyst, formaldehyde adsorption capacity is improved. Adsorption and oxidation reaction experiments are performed in a fixed bed column (di = 10 mm, length = 90 mm). The increase in formaldehyde adsorption associated with the reaction rate of formaldehyde oxidation by metallic Ag is 51 g/mmol. The oxidation reaction of Ag nanoparticles is a bimolecular reaction based on the Langmuir–Hinshelwood mechanism. Formaldehyde can be reduced by 59% and 41% through the role of adsorption and support of catalytic oxidation, respectively. Additionally, harmless gases such as CO2 and H2O are produced within the column. [ABSTRACT FROM AUTHOR]

Nitrogen-doped activated carbon (NDAC) was prepared from saw dust/zinc chloride (2:1) by heating under the flow of ammonia gas at 600 °C, 700 °C, and 800 °C and tested for Acid Brown 14 (AB14) dye adsorption from aquatic solution. The fabricated N-doping activated carbons (NDACs) were characterized by FTIR, TGA, DTA, BET, BJH, MP, t-plot, SEM, EDX, and XRD. The NDACs fabricated at 600 °C, 700 °C, and 800 °C were tested for their capacity to adsorb AB14 dye from water. The nitrogen mass % content in the prepared activated carbon ranged between 17.99 and 21.43%. The NDAC prepared at 600 °C specific surface area, monolayer volume, and mesoporous mean pore diameter were 281.84 m2/g, 64.753 cm3/g, and 2.352 nm, respectively. The NDAC synthesized at 600 °C with a 21.12% nitrogen content was found to be the best one to remove AB14 dye from water and named as NDAC600. The impact of solution pH, initial concentration, and adsorption dosage on the adsorption of AB14 dye by NDAC600 was tested. The adsorption of AB14 dye by NDAC600 was found to be pH dependent, with the optimal elimination of being obtained at pH value 1.5 with a removal efficiency of 89.03%. The adsorption of AB14 dye is attributed to the electrostatic contact between the NDAC600 positively charged sites and the anionic AB14 dye. The AB14 dye adsorption was perfectly designated by using both pseudo-second-order (PSO) and Temkin adsorption kinetic models. The maximum adsorption capacity (Qm) was 909.09 mg/g; moreover, the adsorption process was monolayer sorption of AB14 dye to NDAC600. NDAC600 had proven itself as an effective, available, and green adsorbent for the adsorption of AB14 dye from water and may be applicable to other hazardous pollutants. [ABSTRACT FROM AUTHOR]

As a distinct type of reservoir, tuffaceous tight reservoirs have attracted much attention. However, previous studies on tuffaceous tight reservoirs formed in the burial diagenetic stage are few, particularly regarding the genesis of micropores, which restricts the in-depth exploration of tuffaceous tight oil. According to thin section observation, scanning electron microscopy (SEM) identification, X-ray diffraction (XRD) experiments, elemental analyses, porosity and permeability tests, and pore structure analyses, the micropore characteristics of the Carboniferous tuffaceous tight reservoir formed by burial dissolution in the Santanghu Basin, NW China, are studied. In addition, the cause of the tuff micropore formation and its geological significance are also researched in this paper. The results are as follows: (1) The tuffaceous tight reservoir formed by burial dissolution mainly consists of quartz, feldspar, dolomite, and clay minerals. The reservoir space mainly consists of intergranular pores between minerals, intragranular dissolution pores within feldspars, calcite, dolomite, clay minerals, and locally developed organic matter pores. (2) The formation of micropores in tuff reservoirs formed by burial dissolution is mainly related to the original composition of the tuff. (3) Tuffaceous reservoirs with good physical properties are usually formed at the bottom or top of a large set of source rock. The results of this investigation can provide innovative theoretical evidence for the accumulation mechanism of tuffaceous tight oil formed by burial dissolution. Meanwhile, it can be considered a reference regarding the distribution of and predictions for tuffaceous reservoirs formed by burial dissolution in similar situations in other parts of the world. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Topical drug delivery is highly attractive and yet faces tissue barrier challenges. Different physical and chemical methods have been explored to facilitate topical drug delivery. AREAS COVERED: Ablative fractional laser (AFL) has been widely explored by the scientific community and dermatologists to facilitate topical drug delivery since its advent less than two decades ago. This review introduces the major efforts in exploration of AFL to facilitate transdermal, transungual, and transocular drug delivery in preclinical and clinical settings. EXPERT OPINION: Most of the preclinical and clinical studies find AFL to be safe and highly effective to facilitate topical drug delivery with little restriction on physicochemical properties of drugs. Clinical studies support AFL to enhance drug efficacy, shorten treatment time, reduce pain, improve cosmetic outcomes, reduce systemic drug exposure, and improve safety. Considering most of the clinical trials so far involved a small sample size and were in early phase, future trials will benefit from enrolling a large group of patients for thorough evaluation of the safety and efficacy of AFL-assisted topical drug delivery. The manufacturing of small and less costly AFL devices will also facilitate the translation of AFL-assisted topical drug delivery.

Metal powder injection molding (MIM) has attracted attention as a cost-effective manufacturing method for serial producing complex designed micro metal parts. However, unavoidable micropores are observed in MIM parts that lead to poor bending strength, especially in small-sized products. This disadvantage is significant in the medical field. Ultrasonic vibration assisted surface hardening can be a solution. This surface strengthening method uses an ultrasonically vibrating punch to work-harden the surface, enabling localised hardening in a short time without using highly toxic chemicals or large-scale equipment. In addition, porous metals have the properties of absorbing sound and shock, which allows them to efficiently absorb the energy of ultrasonic vibrations and effectively harden the surface. In this study, we verified the effect of the ultrasonic vibration assisted surface hardening, the influence of the porous structure, and the mechanism of surface strengthening. As a specimen, MIM processed pure copper and stainless steel 316L specimens were used to compare with specimens without porous structure through investigations such as surface hardness test, electron backscatter diffraction analysis, and surface roughness measurement. After hardening, it was confirmed that the MIM specimens had an obviously increased surface hardness and a significantly reduced surface roughness compared to the specimens without porous structure. In addition, the hardening caused a increase in strain near the surface and around the pore walls inside the material. From these results, it is supposed that the pores inside the material absorbed the vibration energy and deformed slightly, and the strain on the surface increased due to the impact effect. This experiment demonstrated that ultrasonic vibration assisted surface hardening can effectively improve the surface strength and roughness of porous metals and can be used as a method that does not impair the original ductility by absorbing vibration energy through pores.

Breathable membranes with micropores enable the transfer of gas molecules while blocking liquids and solids, and have a wide range of applications in medical, industrial, environmental, and energy fields. Breathability is highly influenced by the nature of a material, pore size, and pore structure. Preparation methods and the incorporation of functional materials are responsible for the variety of physical properties and applications of breathable membranes. In this review, the preparation methods of breathable membranes, including blown film extrusion, cast film extrusion, phase separation, and electrospinning, are discussed. According to the antibacterial, hydrophobic, thermal insulation, conductive, and adsorption properties, the application of breathable membranes in the fields of electronics, medicine, textiles, packaging, energy, and the environment are summarized. Perspectives on the development trends and challenges of breathable membranes are discussed. [ABSTRACT FROM AUTHOR]

Achieving the solid–solid conversion of sulfur is a fundamental solution to eliminating the shuttling of soluble polysulfides and improving the cycling stability of lithium‐sulfur batteries. However, the sluggish solid reaction kinetics seriously challenge the battery performance. In this work, a micropore‐confined catalysis strategy to achieve the smooth solid–solid conversion of sulfur is proposed. It is realized by storing sulfur in a microporous carbon host with narrow pore size and uniformly distributed single‐atom Co catalytic sites. The microporous structure avoids the contact of electrolyte solvents with the inner sulfur, preventing the formation and dissolution of polysulfides and efficiently suppressing sulfur loss during cycling. The introduced single‐atom Co catalytic sites promote the charge transfer to accelerate the solid–solid conversion of sulfur. When coupled with a liquid carbonate electrolyte, the battery exhibits a remarkably high Coulombic efficiency (CE) of ≈99.88% and a minimal capacity decay rate of ≈0.016% per cycle for 1000 cycles at 0.5 C. Even when coupled with the solid‐state electrolyte, the battery still delivers a significantly high capacity of 1100 mAh g−1 and a remarkably high CE of ≈99.83% over 200 cycles. This work reveals a promising solution for developing practical stable Li─S batteries. [ABSTRACT FROM AUTHOR]

The micropore contains two distinct morphological types, with type I being present in most apicomplexans. The micropore is a functional nutrient uptake organelle and is involved in artemisinin resistance in Plasmodium. Although possessing distinct morphologies, type I and II micropores share a core set of components across apicomplexan species. A new model for micropore assembly is proposed which involves sequential recruitment of EPS15 (epidermal growth factor receptor substrate-15), Kelch13, and UBP1 (ubiquitin binding protein-1). Future studies should consider the transformation between type I and type II micropores. The micropore, a mysterious structure found in apicomplexan species, was recently shown to be essential for nutrient acquisition in Plasmodium falciparum and Toxoplasma gondii. However, the differences between the micropores of these two parasites questions the nature of a general apicomplexan micropore structure and whether the formation process model from Plasmodium can be applied to other apicomplexans. We analyzed the literature on different apicomplexan micropores and found that T. gondii probably harbors a more representative micropore type than the more widely studied ones in Plasmodium. Using recent knowledge of the Kelch 13 (K13) protein interactome and gene depletion phenotypes in the T. gondii micropore, we propose a model of micropore formation, thus enriching our wider understanding of micropore protein function. [ABSTRACT FROM AUTHOR]

The surface subsidence caused by coal mining in the aeolian sand area of China northwest has seriously affected the soil pore structure and distribution of water and nutrients. In this study, three sample areas (one unexploited area RF, one edge subsidence area MF, and one dynamic subsidence area DF) were set at Dafanpu Coal Mine. The soil moisture content (SMC) and soil organic matter (SOM) content were measured at depths of 0–60 cm for each sampling point. The spatial variability of SMC and SOM in both vertical and horizontal dimensions was examined. Based on computed tomography (CT) technology, the true pore structure of typical soil samples at different depths was scanned, and three-dimensional reconstruction and analysis of soil pores were carried out using Amira Avizo software. The correlation between SMC, SOM content and soil pore parameters was presented, and the influence mechanism of soil pore change on water and nutrient variation in subsidence area was revealed. The results show that the SMC and SOM contents in the subsidence area at a depth of 0–60 cm are lower than those in the unexploited area. The mining-induced subsidence exacerbates the spatial heterogeneity of the horizontal distribution of SMC and SOM content. The variation coefficients of SMC and SOM content increase by 35.77% to 39.56% and 33.29% to 42.74%. The mining-induced subsidence increases the number and porosity of soil pores, particularly the number and porosity of macropores. The connectivity of soil pores in subsidence areas MF and DF is increased by 61.57% and 18.51%, respectively. The SMC and SOM content exhibit significant negative correlations with soil porosity and pore connectivity (P ≤ 0.05). The augmentation of soil porosity and pore connectivity in subsidence areas caused by coal mining are significant factors contributing to the variations in SMC and SOM content. [ABSTRACT FROM AUTHOR]

ABSTRACTPorous geopolymers have been the promising subject over the last decade owing to the functional domains from high surface area, structural stability upon heat and chemists, as well as eco-friendly and economy. Especially, the nano-sized geopolymers are playing a significant role in extensive applications. Here, we summarize recent progress in the development of nanoporous geopolymers in the applications of adsorption as well as catalyst supporter. Generally, microporous geopolymers were synthesized through gas bubbling or combination of zeolite to form partial porous structure, while mesoporous geopolymers were produced by the using of various structure directing agent. However, it remains a challenge to obtain functional materials with narrow porous distribution. Our recent work show that the uses of well-defined template method give rise to finely designed nanoporous geopolymers, which exhibited extremely excellent adsorptivity, solid acidic capacity as well as effective carbon-replication. We discussed well the relationship between nanoporosity regulation and corresponding performances to conclude that just using the bubbling, the compositing of zeolite, or traditional rough template method is difficult to form homogeneous pore structures. By analyzing the connection between the uniform porous structure and its related properties, the well-defined template-method would be recommended to generate emerging nanoporous structures with superior functions.

Porous geopolymers have been the promising subject over the last decade owing to the functional domains from high surface area, structural stability upon heat and chemists, as well as eco-friendly and economy. Especially, the nano-sized geopolymers are playing a significant role in extensive applications. Here, we summarize recent progress in the development of nanoporous geopolymers in the applications of adsorption as well as catalyst supporter. Generally, microporous geopolymers were synthesized through gas bubbling or combination of zeolite to form partial porous structure, while mesoporous geopolymers were produced by the using of various structure directing agent. However, it remains a challenge to obtain functional materials with narrow porous distribution. Our recent work show that the uses of well-defined template method give rise to finely designed nanoporous geopolymers, which exhibited extremely excellent adsorptivity, solid acidic capacity as well as effective carbon-replication. We discussed well the relationship between nanoporosity regulation and corresponding performances to conclude that just using the bubbling, the compositing of zeolite, or traditional rough template method is difficult to form homogeneous pore structures. By analyzing the connection between the uniform porous structure and its related properties, the well-defined template-method would be recommended to generate emerging nanoporous structures with superior functions. [ABSTRACT FROM AUTHOR]

The high overpotential of oxygen reduction reaction (ORR) prevents the wide commercialization of fuel cells and metal‐air batteries. To accelerate the reaction rate, porous electrocatalysts draw attention to obtain a higher specific surface area. However, the effect of micropores on ORR kinetics has not been understood because of the non‐uniform pore sizes, length, and tortuosity of practical electrocatalysts. In this study, we evaluate ORR activity in a micropore using platinum model electrodes with arrays of cylindrical pores with a uniform pore diameter of 1.8 nm. The model electrodes having pore lengths of 45, 100, and 380 nm are fabricated, and their ORR performances are examined by electrochemical measurements and numerical simulations in 0.1 mol dm−3 KOH aqueous solution. The intrinsic ORR activity of the micropore is successfully obtained with the electrode having a pore length of 45 nm, where oxygen transport resistance in the micropore has little effect on ORR. It is found that the intrinsic ORR activity of the micropore is higher than that of a planar Pt surface. X‐ray photoelectron spectroscopy and CO stripping voltammetry indicate a downshift of the d‐band center, which can be the origin of the high intrinsic ORR activity. [ABSTRACT FROM AUTHOR]

The replacement of feldspars is commonly characterized by pseudomorphism and reaction-induced pore generation. However, the effects of compositions of feldspars and fluids on porosity generation during alteration are still poorly understood. In this study, we conducted a series of hydrothermal experiments on plagioclase replacement by 2 M KCl or NaCl aqueous solutions at 600 °C and 150 MPa for 1–8 days, using plagioclase with different compositions (anorthite, An96Ab4; labradorite, An66Ab33Or1; albite, An1Ab99) with or without quartz. Albite replacement by K-feldspar was not affected by the presence of quartz, whereas anorthite was unaltered in the quartz-absent fluid. The replacement of labradorite by KCl(aq) showed different results: in the presence of quartz, labradorite was altered by K-feldspar, whereas in the absence of quartz, alteration proceeded significantly with the generation of large pores hosted by secondary anorthite coupled with euhedral K-feldspar overgrowth. Such textural relationship and oxygen isotope-labeled experiments reveal that silica-deficient fluid enhances the uncoupled dissolution reprecipitation process. The Si and Al ions in the reacted aqueous solution diffused outside the labradorite grains and encountered K+-rich solutions to grow K-feldspar. The experiments with polycrystalline rocks composed of amphibole + labradorite using 2 M KCl aqueous solution indicated the replacement of labradorite grains by anorthite and K-feldspar overgrowth, as found in single-crystal experiments. Our results indicate that the silica concentration in the fluids has different influences on the saturation indices of albite, anorthite, and K-feldspars in saline fluids, which significantly affect the replacement textures and porosity generation in crustal rocks. [ABSTRACT FROM AUTHOR]

Transparency to UV-Vis light and radiopacity of dental resin composites containing zirconia (ZrO2) fillers were investigated. The transparency of the resin composite containing porous ZrO2 spheres was much higher than that containing irregularly shaped ZrO2 particles. Calcination of the porous ZrO2 spheres at high temperatures led to dramatically reduced specific surface areas and pore volumes. The transparency of the resin composite containing the calcined porous ZrO2 spheres drastically decreased as the calcination temperature increased. Then, the enhanced UV-Vis transmittance of the resin composite containing porous ZrO2 spheres is attributed to the concentration and physical characteristics of the pores. The radiopacity of the resin composites containing porous ZrO2 spheres increased slightly with increasing calcination temperature. This study revealed that the internal structure of the ZrO2 fillers mainly influenced in the UV-Vis light transmittance of the resin composites. [ABSTRACT FROM AUTHOR]

Abstract The high overpotential of oxygen reduction reaction (ORR) prevents the wide commercialization of fuel cells and metal‐air batteries. To accelerate the reaction rate, porous electrocatalysts draw attention to obtain a higher specific surface area. However, the effect of micropores on ORR kinetics has not been understood because of the non‐uniform pore sizes, length, and tortuosity of practical electrocatalysts. In this study, we evaluate ORR activity in a micropore using platinum model electrodes with arrays of cylindrical pores with a uniform pore diameter of 1.8 nm. The model electrodes having pore lengths of 45, 100, and 380 nm are fabricated, and their ORR performances are examined by electrochemical measurements and numerical simulations in 0.1 mol dm−3 KOH aqueous solution. The intrinsic ORR activity of the micropore is successfully obtained with the electrode having a pore length of 45 nm, where oxygen transport resistance in the micropore has little effect on ORR. It is found that the intrinsic ORR activity of the micropore is higher than that of a planar Pt surface. X‐ray photoelectron spectroscopy and CO stripping voltammetry indicate a downshift of the d‐band center, which can be the origin of the high intrinsic ORR activity.

Porous dielectric membranes that perform insulator-based dielectrophoresis or electroosmotic pumping are commonly used in microchip technologies. However, there are few fundamental studies on the electrokinetic flow patterns of single microparticles around a single micropore in a thin dielectric film. Such a study would provide fundamental insights into the electrokinetic phenomena around a micropore, with practical applications regarding the manipulation of single cells and microparticles by focused electric fields. We have fabricated a device around a silicon nitride film with a single micropore (2-4 µm in diameter) which has the ability to locally focus electric fields on the micropore. Single microscale polystyrene beads were used to study the electrokinetic flow patterns. A mathematical model was developed to support the experimental study and evaluate the electric field distribution, fluid motion, and bead trajectories. Good agreement was found between the mathematic model and the experimental data. We show that the combination of electroosmotic flow and dielectrophoretic force induced by direct current through a single micropore can be used to trap, agglomerate, and repel microparticles around a single micropore without an external pump. The scale of our system is practically relevant for the manipulation of single mammalian cells, and we anticipate that our single-micropore approach will be directly employable in applications ranging from fundamental single cell analyses to high-precision single cell electroporation or cell fusion.

Ceramics are recognized as highly suitable materials for creating guided bone regeneration (GBR) barrier membranes due to their bioresorbable and osteoconductive properties. However, techniques have not been fully developed for the production of ceramic membranes with the appropriate fiber thickness and pore size. In this study, a thin silica nonwoven fabric with pores smaller than cells, achieved by nanofiber technology, was prepared by electrospinning, and its potential as a GBR barrier membrane was explored. In addition, efforts were made to elucidate the nanoscale fiber formation mechanism through molecular dynamics-based geometric optimization using solid-state 29Si-NMR data. As a result, a thin silica nonwoven fabric composed of nanofibers and micropores was prepared by electrospinning a silica gel prepared by lowering the TEOS-to-water ratio during the sol-gel reaction. Insufficient water addition during the sol-gel reaction caused a decrease in the number of siloxane bonds, resulting in a linear growth behavior of the silica molecules instead of the original network growth behavior. This led to a decrease in fiber thickness, which in turn caused a decrease in pore size. The thin silica nonwoven fabric showed exceptional performance in the cell occlusion ability test, suggesting its strong potential as a GBR barrier membrane. [ABSTRACT FROM AUTHOR]

Comprising a relatively large amount of industrial solid waste, the high-value utilization of phosphogypsum (PG) is closely related to the sustainable development of resource materials and the protection of the ecological environment. PG can improve some of the shortcomings of geopolymers, but there is a lack of systematic research on the specific influencing factors as well as the mechanism of the two in a hydration reaction. In this study, the effects of the Si/Al, Na/Al and Ca/Al ratios on the micropores as well as the hydration products of phosphogypsum-modified geopolymer material (PMGM) are systematically explored via macroscopic and microscopic tests from the molar ratios of the raw material's target components. By changing the molar ratio, the generation of hydration products is affected, thereby altering the properties of the material. The effects of each molar ratio on paste workability, capillary water absorption, drying shrinkage and self shrinkage are systematically analyzed, while the types, productions, and micropores of hydration products are analyzed via XRD and SEM. This study provides a new idea for the large-scale recycling of PG and makes a systematic investigation of its hydration mechanism, which can provide a reference for the reaction principle of PG with geopolymers. [ABSTRACT FROM AUTHOR]

Micropores fabricated on organic polymer films have a wide range of applications in fields such as microfiltration, new energy, and biomedical separation. The use of laser processing technology can complete the processing of micropores on the surface of ultrathin films with high precision, but there is still some difficulty in the processing of ultrathick films. In this paper, a picosecond ultraviolet (UV) laser was used to explore the high-precision manufacturing process of micropores on the surface of ultrathick polyimide (PI) films. The effects of laser power, laser frequency, and scanning speed on the cone angle and spatter deposition area of micropores' fabrication on ultrathick PI were studied based on orthogonal experiments. The mechanism of processing micropores on ultrathick PI was analyzed by studying the deposition area and morphology of the spatter generated during the laser ablation process. It was found that high-quality micropores can be fabricated at low laser frequency and high power. [ABSTRACT FROM AUTHOR]

The development of wire arc additive manufacturing (WAAM) provides a new solution for manufacturing aluminum alloy (AA) components used in lightweight mobile heat storage equipment. AA5356 component is deposited at a wire feed speed of 7.3 m/min and a welding speed of 1000 mm/min with the cold metal transfer-advanced mode. Adjusting the deposition angle to 90° between layers can enhance the microstructure and mechanical properties of the WAAM AA5356 component. The quasi in situ idea is proposed to investigate the microstructures, defects evolution, and mechanical property differences during the successive deposited. The results showed that the average grain size increases with increasing deposition height. The microstructures are uniform, except for the interlayer with refined equiaxed grains. The porosity increases gradually from 1.23% to 1.75% as the deposition height increases, and the average diameter of the micropores increases from 16.54 μm to 21.91 μm. In contrast, the microhardness of WAAM AA5356 component gradually decreases, and the microhardness of the interlayer area is higher than that of the innerlayer. The ultimate tensile strength, yield strength, and elongation are 286 MPa, 142 MPa, and 23%, respectively. Compared with casting AA5356, the ultimate tensile and yield strengths are 32.2% and 40.5% greater, respectively, while the elongation is almost equal. As the grain sizes increase with the heat accumulation effect, the microhardness decreases and the elongation increases while the tensile strength decreases, mainly due to the high proportion of large micropores in the top area.

The present work reports the results of a systematic study on the evolution of the morphological properties of porous carbons derived from coffee waste using a one-pot potassium-hydroxide-assisted process at temperatures in the range of 400–900 °C. Raw materials and obtained carbons were studied by TG, DTG, SEM and nitrogen adsorption porosimetry. The decomposition temperature ranges for hemicellulose, cellulose and lignin as the main component of the feedstock have been established. It is shown that the proposed method for the thermochemical treatment of coffee waste makes it possible to obtain activated carbon with a controllable pore size distribution and a high specific surface area (up to 1050 m2/g). A comparative study of the evolution of the distribution of pore size, pore area and pore volume has been carried out based on the BJH and NL-DFT (slit-like pores approximation) methods. The fractal dimension of the obtained carbons has been calculated by Frenkel–Halsey–Hill method for single-layer and multilayer adsorptions. [ABSTRACT FROM AUTHOR]

The effective utilization of charcoal and tar byproducts is a challenge for pyrolysis gasification of bamboo. Herein, the bamboo tar was modified via polymerization and acted as a new adhesive for the preparation of excellent bamboo-charcoal-derived molding activated carbon (MBAC). As compared with pristine tar and other adhesives, the aromatization of tar with phenol increased its molecular weight, oxygenic functional groups, and thermal stability, leading to the decreased blocking impact of charcoal pore and improved bonding and pyrolytic crosslinking effect between charcoal particles. These further contribute to the high mechanical strength, specific surface area, pore volume, and amount of oxygenic functional groups for fabricated MBAC. Owing to the high microporous volume of MBAC, it exhibited 385 mg·g−1 toluene and 75.2% tetrachloride gas adsorption performances. Moreover, the pseudo-first-order, pseudo-second-order, and Bangham models were used to evaluate the kinetic data. The toluene adsorption process conforms to the Bangham kinetic model, suggesting that the diffusion mechanism of toluene adsorption mainly followed intraparticle diffusion. [ABSTRACT FROM AUTHOR]

Various ferrierite zeolites were investigated as catalysts for the dimethyl ether (DME)-to-olefin (DTO) reactions to efficiently synthesize n-butene, such as 1-butene, trans-2-butene, and cis-2-butene except for iso-butene using a fixed-bed flow reactor. Twenty P-loaded ferrierite zeolites with different structural parameters and acidic properties were prepared by the impregnation method by varying the P content and the temperature of air calcination as a pretreatment. The zeolites were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and NH3 temperature-programmed desorption (NH3-TPD). Micropore surface area, external surface area, total pore volume, micropore volume, and weak and strong acid sites affected the DTO reaction behavior. A high n-butene yield (31.2 C-mol%) was observed, which is higher than the previously reported maximum yield (27.6 C-mol%). Multiple regression analysis showed that micropore surface area and strong acid sites had a high correlation with n-butene yield. Based on our findings, we explained the reaction mechanism for selective n-butene synthesis except for iso-butene in the DTO reaction by the dual cycle model. [ABSTRACT FROM AUTHOR]

In order to investigate the material removal mechanism, technological rules, and optimization of technological parameters, experimental investigations of laser drilling on polystyrene (PS) with single-pulse and multi-pulse nanosecond solidstate laser at 266 nm based on the single factor experiment and orthogonal experiment method were carried out. The material removal mechanism was analyzed, and the relationship between the diameter and depth of the micropore and the number of laser pulses, the laser pulse energy and the defocusing distance was obtained. As well as an optimized combination of process parameters meeting the requirements was acquired. The experimental results show that when the laser pulse energy is 0.110 mJ, the micropore with regular shape, better roundness, and smaller recast layer was obtained ; when the laser pulse energy is 0.500 mJ, the shape and roundness of micropore becomes worse, and the width of recast layer becomes larger at the same time. During the multi-pulse drilling, no recast layer is present at the entrance of the through-hole with the laser pulse energy of 0.040 mJ, and the removal mechanism is mainly photochemical. With the laser pulse energy of 0.390 mJ, the recast layer is more visible at the entrance of the through-hole and over-ablation occurs at the entrance edge, the removal mechanism is mainly photothermal. Laser pulse energy and defocusing distance have a large effect on the hole diameter, and the number of laser pulses and positive defocusing distance have a large effect on the hole depth. The optimized combination of parameters obtained from the orthogonal experiments that micropores of good quality can be produced when the number of laser pulses is 50, laser pulse energy is 0.021 mJ and defocusing distance is 0 µm. This investigation provides a reference for 266 nm nanosecond laser processing of polystyrene target. [ABSTRACT FROM AUTHOR]

An efficient catalytic chemical vapor deposition method utilizing an Fe-Mo/MgO-supported catalyst was developed, allowing the highly selective synthesis of double-walled carbon nanotubes (DWCNTs) in high yield, exceeding 89 %. The carbon yield, tube diameter, and crystallinity of the synthesized DWCNTs were characterized using high-resolution transmission electron microscopy, field-emission scanning electron microscopy, thermogravimetric analysis, and Raman spectroscopy. The nanopore structure and adsorption characteristics of the DWCNTs purified by removing the support and catalyst (i.e., Fe-Mo/MgO) were analyzed via N 2 adsorption–desorption measurements at 77 K. A remarkable advantage of the highly enriched DWCNTs with small bundle network structures is that guest molecules can easily access the outer (i.e., external) surface of the DWCNTs, resulting in a large specific surface area (SSA) of >691 m2 g−1 and pore volume of 2.70 mL g−1 in the double-walled structures. Thus, highly enriched DWCNTs with large pore volumes and SSAs prepared via facile solution-based processes can yield CNT-based structures for applications in high-performance energy storage. [Display omitted] • Efficient Fe-Mo/MgO catalyst for high-yield DWCNT synthesis (>89 %). • DWCNTs characterized via TEM, SEM, TGA, and Raman spectroscopy. • Purified DWCNTs analyzed via N 2 adsorption–desorption at 77 K. • DWCNTs with high SSA (>691 m2/g) and pore volume (2.70 mL g−1). • DWCNTs ideal for high-performance energy storage applications. [ABSTRACT FROM AUTHOR]

[Display omitted] The adsorption of the nitrate ion by the cylindrical pore of single-walled carbon nanotubes (SWCNT) was found to be aided by an acidic adsorbed layer. Adsorbed water in the vicinity of the pore wall can supply protons through ionization, forming the acidic layer, according to Raman spectra and results of solution pH fluctuations caused by ion species adsorption. Such an acidic adsorbed layer leads to surplus adsorption of anionic species where the adsorbed amount of nitrate ions is much larger than that of cations. Also, we could observe the Raman bands being assignable to the symmetrical stretching mode at an extremely high-frequency region for nano-restricted nitrate ions compared to any other bulk phases. The abnormal band shift of adsorbed nitrate ions indicates that the nitrate ions are confined in the pore under the effects of nanoconfinement by the pore and the strong interaction with the acidic layer in the pore. Our results warn that we have to construct the adsorption model of aqueous electrolytes confined in carbon pores by deliberating the acid layer formed by the adsorbed water. [ABSTRACT FROM AUTHOR]

Background: Carbon black, which has a low utilization rate, is a powdered carbon material produced by incomplete combustion or decomposition of hydrocarbons. Carbon black is used in rubber, coating and ink industries, the product quality will be affected due to its powder structure, and serious environmental pollution will be caused in the stacking process. However, carbon black used as the raw material for the preparation of porous carbon materials with high volatile organic compounds (VOCs) adsorption capacity, which can realize the resource utilization of carbon black and environmental protection. Results: Porous carbon based adsorbents (PCBAs) were prepared by low‐temperature physical pore‐forming and high‐temperature chemical pore‐forming with waste carbon black as raw material and (NH4)2CO3 as pore‐forming agent. The high pore‐forming temperature was beneficial to the pore structure to be formed. The surface morphology of the prepared PCBAs was more wrinkled and loose, and the specific surface area, micropore ratio and graphitization degree showed a volcanic change trend with the increase of pore‐forming temperature. The micropore ratio reached the maximum (81.7%) and the graphitization degree reached the maximum (ID/IG = 1.15) at the pore‐forming temperature of 850 °C. When the pore‐forming temperature was 850 °C, the toluene saturated adsorption capacity of PCBA850 adsorbent was 298.9 mg/g. In addition, the kinetic fitting results show that the adsorption behavior of toluene molecules on the adsorbent is mainly affected by the pore diffusion. Conclusion: Although increasing pore‐forming temperature did not change the surface chemical properties of PCBAs, high temperature pore‐forming could significantly increase the microporosity and surface area of PCBAs. The high microporous ratio and specific surface area can provide more active sites for toluene adsorption, thus improving the toluene adsorption performance of the porous carbon‐based adsorbent. In addition, the PCBA adsorbent prepared at 850 °C can restore the toluene adsorption performance at 120 °C, which provides a possibility for its practical application. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]