In summary, with the increasing service temperature of aero-engines, the abradable/environmental barrier coatings (A/EBCs) that match SiC_f/SiC ceramic matrix composites (CMCs) become a key research direction. This review represents the research progress of A/EBCs in material design, microstructural regulation and performance evaluation, and points out that the current challenges mainly include thermal expansion mismatch between conventional coating materials and CMC substrate, poor high-temperature stability of lubricants, difficult balance between multi-scale pore structure and multi-performance, and lack of standardized evaluation systems and test standards suitable for multi-field coupling service environment. In the future, the research and development of A/EBCs should focus on the multi-objective synergistic design of material composition, multi-scale microstructure and performance evaluation system. It is necessary to strengthen the analysis of failure mechanism under multi-physical field coupling environment, develop new high-temperature stable matrix and lubricant materials, realize the precise regulation of multi-scale pore and interface structure, and establish a standardized preparation and performance evaluation system. Through the breakthrough of the above key technologies, the comprehensive performance and service durability of A/EBCs will be effectively improved, so as to promote the leapfrog development of high-temperature sealing technology and provide an important support for the performance improvement of next-generation aero-engines.

Quartz ceramics (SiO₂) possess unique properties such as low thermal expansion, excellent chemical stability, and outstanding dielectric performance, making them widely used in semiconductor manufacturing, optoelectronic devices, and high-frequency electronic components. Traditional sintering of quartz ceramics typically requires temperatures above 1000 ℃, which inevitably induces polymorphic transformations from α-quartz to β-quartz or cristobalite, hindering the preparation of single-phaseα-quartz ceramics. Recently, the cold sintering process (CSP) has emerged as a promising low-temperature densification route for ceramics, utilizing transient liquid phases to induce "dissolution-precipitation" or interfacial reaction mechanisms. However, for low-solubility ceramics such as quartz, CSP often fails to achieve full densification and crystallization due to insufficient dissolution kinetics and weak interfacial reactivity. The critical scientific problem addressed in this work is how to effectively trigger the amorphous-to-crystalline phase transition of low-solubility quartz at low temperature, thereby enabling the preparation of denseα-quartz ceramics.

This study systematically investigates the cooperative effects of transient solvent alkalinity, sintering temperature, and uniaxial pressure on the amorphous-to-α-quartz phase transition during CSP. A transient alkaline liquid phase is introduced to regulate interfacial reactions and crystallization kinetics, aiming to provide a theoretical basis and technical strategy for the low-temperature processing of low-solubility ceramics.

Amorphous mesoporous silica (SBA-15) powders were used as the starting material. The powders were homogeneously mixed with different transient solvent phases: deionized water (neutral), 5 mol·L^-1 NH₃·H₂O (weak alkaline), and NaOH solutions of varying concentrations (0.5-10.0 mol·L^-1, strong alkaline). Approximately 0.4 g of powder was thoroughly ground with the liquid phase in a mortar and then loaded into a 10 mm diameter steel die. Uniaxial pressures ranging from 200 MPa to 600 MPa were applied, while the sintering temperature was varied between 200 ℃ and 350 ℃. Heating was conducted at a rate of 15 ℃·min^-1 and held for 40 min at the target temperature. After natural cooling, the sintered pellets were mechanically polished for further characterization.

The density of the cold-sintered ceramics was calculated by dimensional and weight measurements using a vernier caliper and electronic balance, and relative density was determined based on the theoretical density of quartz (2.2 g·cm^-3). Phase composition and structural evolution were analyzed using X-ray diffraction (XRD, Cu Kα radiation, λ = 0.154 06 nm, 50 kV, 100 mA, scanning range 10 °-90 °, step size 0.01). Fourier-transform infrared spectroscopy (FTIR-ATR) was used to identify bonding characteristics and confirm phase transitions. Microstructural evolution and fracture features were observed by field-emission scanning electron microscopy (FE-SEM). The mechanical properties of the sintered ceramics were evaluated by Vickers hardness tests (3 kgf load, 10 s dwell), flexural strength using the modified small punch (MSP) method, and fracture toughness (K_IC) calculated by the Anstis equation. Poisson's ratio and Young's modulus were determined by ultrasonic measurements.

This experimental design allows for a systematic investigation of how transient solvent alkalinity, temperature, and pressure cooperatively affect densification and amorphous-to-crystalline transformation during CSP of quartz.

The phase composition of the sintered bodies was strongly influenced by the type and concentration of transient solvent. Without a liquid phase or with neutral water, the sintered samples remained largely amorphous and exhibited low relative density (~80%). Weak alkaline NH₃·H₂O increased compaction and relative density (~92%) but failed to trigger phase transformation. In contrast, strong alkaline NaOH solutions (≥3 mol·L^-1) effectively promoted the dissolution of Si-OH surface species, forming soluble silicate intermediates. These intermediates subsequently underwent reprecipitation and recrystallization under external pressure and temperature, leading to complete transformation into α-quartz at 300 ℃ and 500 MPa. XRD and FTIR confirmed the disappearance of the amorphous broad peak and the emergence of α-quartz characteristic double peaks at 798 cm^-1 and 778 cm^-1, indicating a complete amorphous-to-α-quartz transition.

A clear alkalinity-dependent phase transition sequence was identified: amorphous → keatite (0.5 mol·L^-1 NaOH) → keatite +stishovite (1 mol·L^-1) → keatite + α-quartz (3 mol·L^-1) → α-quartz (≥5 mol·L^-1). Simultaneously, relative density increased from 71% (no solvent) to 95.7% (10 mol·L^-1 NaOH). SEM revealed that strong alkalinity produced well-defined grain boundaries and uniform microstructures, while weak or neutral conditions resulted in porous, poorly bonded networks.

The phase transition was also sensitive to sintering temperature and pressure. At 200 ℃, no crystallization occurred even at 600 MPa. Crystallization initiated at 250 ℃ and 300 MPa, and complete α-quartz formation occurred at ≥300 ℃ and ≥400 MPa. Increasing pressure facilitated particle rearrangement, pore elimination, and enhanced atomic diffusion at the interface, accelerating phase transition. A comprehensive temperature-pressure-phase diagram was established, clearly delineating the non-crystalline, partially crystalline, and fully crystalline regions.

Mechanical properties were strongly correlated with microstructure and phase composition. The α-quartz ceramics cold-sintered with 5 mol·L^-1 NaOH exhibited a Vickers hardness of 5.1 GPa, Young's modulus of 67.8 GPa, fracture toughness of 0.98 MPa·m^1/2, and flexural strength of (58 ± 7) MPa. These values represent increases of 30%, 40%, and 110% in hardness, modulus, and toughness, respectively, compared to the amorphous samples. The enhanced mechanical properties are attributed to the formation of well-bonded crystalline interfaces that enable efficient stress transfer and crack deflection, unlike the disordered amorphous structure.

This work demonstrates a controllable strategy to induce amorphous-to-α-quartz transformation in low-solubility silica ceramics through the regulation of transient solvent alkalinity during cold sintering. By introducing strong alkaline NaOH solutions (≥3 mol·L^-1), the activation energy for crystallization can be significantly reduced, enabling complete transformation at 300 ℃ under 500 MPa. The critical crystallization threshold was identified at 250 ℃ and 200 MPa, and a detailed temperature-pressure-phase diagram was established to illustrate the transition pathways. The resulting ceramics achieved a relative density above 95% and exhibited excellent mechanical performance, including a Vickers hardness of 5.1 GPa, Young's modulus of 67.8 GPa, fracture toughness of 0.98 MPa·m^1/2, and flexural strength of (58 ± 7) MPa. These results clearly indicate that alkaline regulation during CSP not only enables precise control of phase structure but also produces dense, mechanically robust α-quartz ceramics at dramatically reduced sintering temperatures. This approach provides both fundamental insights and practical guidance for the low-energy fabrication of advanced low-solubility ceramic components.

In summary, SOCs thin film preparation technologies can form a diversified system, but some common challenges remain. Although vapor-phase technologies have excellent performance, they generally face high equipment costs and great difficulty in scaling up. Liquid-phase technologies are prone to film cracks or pores due to drying and sintering stress. Future research should focus on three core directions, i.e., 1) promoting intermediate and low-temperature operation, further expanding the low-temperature application range of batteries through interface regulation and film formation process optimization; 2) pursuing high performance, developing three-dimensional structured films to expand reaction interfaces and improve mass transfer and catalytic efficiency; and 3) accelerating commercialization, optimizing low-cost preparation processes combined with intelligent manufacturing technologies, and breaking through the key technical bottlenecks of new film formation technologies. Thin film preparation technology will continue to be a core breakthrough to solve the high-temperature dependence and performance attenuation of SOCs, promoting their transition from laboratory research to commercial application.

With the advancement of the era, the demand for ultraviolet photodetectors in environmental monitoring and communication security continues to grow, leading to increasingly stringent performance requirements. In this case, self-driven ultraviolet photodetectors emerge to meet the needs of energy conservation and device miniaturization. However, conventional self-driven ultraviolet photodetectors still face some challenges such as low efficiency in photo-generated carrier separation, poor photoresponse performance, and limited response speed. Ferroelectric thin films with a high remnant polarization can form a depolarization field that penetrates the entire bulk material, enabling an effective separation of internally generated photo-generated electrons and holes. This provides a promising solution to the aforementioned issues. Pb(Zr_xTi1-x)O₃(PZT) is a typical ABO₃-type perovskite ferroelectric material. This material is widely used in ferroelectric memories, micro-electromechanical systems, and photodetectors due to its excellent ferroelectric, piezoelectric, and photoelectric properties. Extensive studies show that the composition significantly affects the crystal phase structure and ferroelectric properties of PZT thin films. However, its impact on the photoelectric performance requires a further systematic investigation. This work was to analyze the photoelectric characteristics of PZT thin films with different Zr/Ti ratios, in order to elucidate the influence of compositional modulation on the photoelectric effect.

Pb(Zr_xTi₁-x)O₃ ferroelectric thin films with different Zr/Ti ratios were prepared by a sol-gel method. The selected precursors and solvents were high-purity lead acetate [Pb(CH₃COO)₂·3H₂O], zirconium n-propoxide (C₁₂H₂₈O₄Zr), and titanium isopropoxide (C₁₂H₂₈O₄Ti) as sources for lead, zirconium, and titanium, respectively, glacial acetic acid as a chelating agent, and n-propanol as a stabilizer. Semitransparent gold electrodes were deposited on the surface of the thin films by a model VZZ-300 high-vacuum thermal evaporation system (VANNO Co., China) to fabricate self-driven ultraviolet photodetectors with an Au/PZT/FTO vertical structure. The crystal structure of the films was characterized by a model D8 Advance X-ray diffractometer (XRD, Bruker Co., USA). The surface roughness of the films was determined by an atomic force microscope (AFM, Bruker Dimension Edge Co., USA). The optical properties of the films were analyzed by a model UV-3600 Plus ultraviolet-visible-near-infrared spectrophotometer (UV-Vis-NIR, Shimadzu, Japan). The ferroelectric properties were measured by a model Precision LC II ferroelectric test system (Radiant Co., USA). The current-time (I-t) curves were obtained by a model Keithley 2400 source meter, with a 150 W ultraviolet-enhanced xenon lamp as a light source.

The XRD patterns indicate that the three prepared PZT thin films with different Zr/Ti ratios all exhibit a typical perovskite structure, and no diffraction peaks from impurity phases appear aside from those originating from the FTO substrate. As the Zr content increases, the surface morphology of the films transitions from elongated needle-like structures to island-like structures, and finally to wavy undulations. The lowest root mean square (RMS) roughness of 2.62 nm is obtained at a Zr/Ti ratio of 0.52:0.48. The remnant polarization first increases from 27.9 μC/cm² (Zr/Ti=0.49/0.51) to a maximum of 33.2 μC/cm² (Zr/Ti=0.52/0.48), and then decreases to 31.1 μC/cm² (Zr/Ti=0.55/0.45) as the Zr content increases. A higher remnant polarization is beneficial to forming a stronger built-in electric field, thereby improving the separation efficiency of photogenerated carriers. The PZT films with different Zr/Ti ratios are all wide-bandgap semiconductors (>3.6 eV). As the Zr content increases, the bandgap widens from 3.60 eV to 3.68 eV, showing a blue-shift trend. When a negative poling voltage is applied, the depolarization field inside the PZT aligns with the built-in field induced by the interfacial Schottky barrier, synergistically enhancing the driving force for carrier separation and leading to a significant increase in photocurrent. For the sample with a Zr/Ti ratio of 0.52:0.48 at a poling voltage of -2 V, the responsivity and detectivity reach 3.2 mA/W and 0.33×10¹¹ Jones, respectively. Even under a weak illumination of as low as 0.17929 mW/cm², the device still generates a photocurrent of 1.02 nA, demonstrating the excellent detection sensitivity.

Pb(Zr_xTi₁-x)O₃ ferroelectric thin films with different zirconium-to-titanium ratios (i.e., Zr/Ti=0.49:0.51, 0.52:0.48, 0.55:0.45) were fabricated by a sol-gel method, and self-driven ultraviolet photodetectors with an Au/PZT/FTO structure were constructed. The structural characterization revealed that all PZT thin films exhibited a pure perovskite phase with a good crystalline quality. The AFM analysis indicated that the film surfaces were smooth, dense, and displayed a uniform grain distribution. The ferroelectric property measurements further confirmed that all films with different Zr/Ti ratios showed characteristic ferroelectric hysteresis loops and possessed a high remnant polarization, having a maximum value of 33.2 μC/cm² at Zr/Ti=0.52:0.48. The results of photoelectric tests demonstrated that the device based on this optimal composition exhibited stable and reproducible photocurrent responses. At a poling voltage of -2 V, its responsivity and detectivity were significantly enhanced. In summary, the rational adjustment of the Zr/Ti ratio could effectively optimize both the ferroelectric properties of PZT thin films and the photoelectric characteristics of the corresponding devices. This work could innovatively utilize the inherent bulk depolarization field of PZT ferroelectrics as a driving force to achieve an efficient separation of photogenerated electron-hole pairs. Moreover, it could provide a systematic optimization strategy from the perspectives of compositional design and polarization modulation, offering an effective material- and physics-based solution to overcome the key bottlenecks of low responsivity and detectivity in self-driven ultraviolet photodetectors.

The hydration of binder is an exothermic reaction, which results in an obvious temperature increase in concrete in the early hydration period. The shrinkage of hardened concrete due to the temperature drop is a main cracking trigger of concrete. A kind of temperature rising inhibitor is developed to decrease the hydration heat of binder in early hydration age, which can reduce the cracking risk of concrete. Cyclodextrin is a main functional composition of the temperature rising inhibitor. C₃A is an important clinker mineral influencing the early exothermal characteristics of Portland cement. In this paper, the effect of cyclodextrin on the hydration of tricalcium aluminate-gypsum (C₃A-CaSO₄·2H₂O) was investigated. This work could favor understanding the action mechanism of the temperature rising inhibitor to reduce the cracking risk of concrete structures.

Pure C₃A was calcined, the chemical pure gypsum and cyclodextrin was used. The hydration exothermal curves of C₃A-CaSO₄·2H₂O pastes containing different dosages of cyclodextrin were measured. The hydration products of C₃A-CaSO₄·2H₂O pastes containing different dosages of cyclodextrin in different ages were in-situ determined by quantitative X-ray diffraction (QXRD). The morphology of hydration products on the surface of C₃A particles immersed in different solutions was characterized by scanning electron microscopy (SEM). The etching situation on the surface of C₃A particles washed by different solutions was determined by three-dimensional white light interferometric surface profilometry.

The beginning time of second hydration of C₃A moves up and its exothermic rate decreases, but its reacting time prolongs with the increase of cyclodextrin dosage. The heat output of C₃A during its second hydration stage varies little. The consumption of C₃A and CaSO₄·2H₂O increases continuously and the exhausting time of gypsum reduces with the increase of cyclodextrin dosage. The forming quantity of ettringate in the paste containing cyclodextrin is greater than that in controlling paste. The transformation of ettringate to AFm is suppressed after the exhaust of gypsum. Cyclodextrin can expedite the dissolution of C₃A in CaSO₄ solution to form more deeper etch pits on the surface of C₃A particles, which speeds up the hydration of C₃A. Needle-like ettringite changes to stick-like one, and the transformation of ettringite to AFm restrains when cyclodextrin exists in pastes.

Cyclodextrin could promote the initial hydration of C₃A to move up the beginning of the second hydration of C₃A. The consumption of C₃A and CaSO₄·2H₂O increased continuously in the first hydration stage and the exhausting time of gypsum reduced with the increase of cyclodextrin dosage. Cyclodextrin reduced the reaction speed and prolonged reacting time of C₃A during its second hydration stage, its heat output changed little. Cyclodextrin could enhance the dissolution of C₃A in gypsum solution to form more deep etch pits on the surface of C₃A particles, speeding up the hydration of C₃A. Cyclodextrin could change needle-like ettringate to stick-like one and suppress the transformation of ettringate to AFm.

Phosphorus (P) is an essential nutrient for aquatic ecosystems. However, excessive phosphorus discharge into surface water is one of the primary causes of eutrophication, thus triggering algal blooms, degrading water quality, and threatening aquatic life as well as human health. It is widely recognized that even low concentrations of phosphorus can significantly accelerate eutrophication processes, making efficient phosphorus removal a critical issue in water pollution control. Among the existing treatment technologies, adsorption has attracted increasing attention due to its operational simplicity, high efficiency for low-concentration phosphorus, and limited risk of secondary pollution.

Coal fly ash is one of the most abundant industrial solid wastes that are generated in large quantities in coal-fired power plants. Although its comprehensive utilization rate is increased, a considerable fraction of fly ash is still disposed of by landfilling or stockpiling, posing long-term environmental risks. Fly ash is a promising precursor for the preparation of ceramic materials due to its high contents of SiO₂ and Al₂O₃. Moreover, the presence of Ca, Mg, and other alkaline components endows fly-ash-derived materials with a potential chemical affinity toward phosphate species. Transforming fly ash into functional ceramsite for water treatment therefore represents a typical "waste-to-resource" strategy.

Previous studies explored fly-ash-based ceramsite or related materials for phosphorus removal. However, most of them focused primarily on adsorption performance evaluation, while systematic optimization of preparation parameters and in-depth clarification of phosphorus removal mechanisms remained insufficient. Such limitations hinder the rational design and engineering application of these materials. In this work, fly ash was used as a main raw material, supplemented with municipal sludge, furnace slag, and cement to prepare porous ceramsite for phosphorus removal. The adsorption behavior, comprehensive physicochemical characterization, preparation conditions, and removal mechanism were systematically investigated.

Fly-ash-based ceramsite was prepared by a disc granulation method. Fly ash was mixed with municipal sludge as a pore-forming component, furnace slag as a functional additive, and cement as a binder. After granulation with deionized water, green pellets with a controlled particle size were obtained and subjected to preheating and high-temperature sintering. To optimize the preparation process, a Taguchi L25 (5⁶) orthogonal experimental design was employed, considering six factors, i.e., fly ash-to-sludge ratio, preheating temperature, preheating time, sintering temperature, sintering time, and heating rate. Phosphate removal efficiency was selected as an evaluation index to determine the optimal preparation parameters.

Batch adsorption experiments were conducted using simulated phosphate solutions prepared from potassium dihydrogen phosphate. The effects of dosage, initial pH value, coexisting ions, and humic acid were systematically investigated to evaluate adsorption adaptability under different water chemistry conditions. Adsorption isotherms were analyzed using the Langmuir, the Freundlich, the Sips, and the Dubinin-Radushkevich models, while adsorption kinetics were interpreted using pseudo-first-order, pseudo-second-order models, i.e., Elovich, and intraparticle diffusion models.

The physicochemical properties and adsorption mechanisms of the ceramsite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In addition, the leaching risk of heavy metals was also assessed using standard toxicity characteristic leaching procedures to evaluate environmental safety.

The results of orthogonal experimental analysis reveal that sintering temperature is the most dominant factor affecting phosphate removal performance, following by sintering time and heating rate. The excessively high sintering temperature leads to pore collapse and crystallization of stable mineral phases, thereby reducing adsorption capacity. The optimal preparation conditions obtained are a fly ash-to-municipal sludge ratio of 7∶3, preheating at 600 ℃ for 5 min, sintering at 1050 ℃ for 5 min, and a heating rate of 5 ℃/min. Under the optimal conditions, the ceramsite achieves a phosphate removal efficiency of 90.77%, which is significantly higher than that of all orthogonal experimental groups.

The SEM images show that the optimized ceramsite has a rough surface with abundant interconnected pores, originating from the thermal decomposition of organic matter in municipal sludge and gas evolution during high-temperature reactions. The XRD patterns indicate that mullite and anorthite are the dominant crystalline phases, while Ca- and Mg-containing components are retained in reactive forms. The results of batch experiments demonstrate that phosphate removal efficiency increases with increasing dosage but decreases under strong alkaline conditions. The ceramsite maintains effective phosphorus removal in a wide range of pH values, with optimal performance under weakly acidic to neutral conditions.

The coexisting anions exhibit varying degrees of inhibition on phosphate removal, following a decreasing order CO₃^2- >HCO₃^- > SO₄^2- > NO₃^- > Cl^-, whereas common monovalent cations show a negligible influence. In contrast, the presence of Ca²⁺ and Mg²⁺ significantly enhances phosphate removal due to additional precipitation reactions. Humic acid notably suppresses adsorption via competing for active sites and altering phosphate speciation.

Adsorption isotherm analysis shows that the Langmuir and Sips models both fit the experimental data, while the Sips model provides a better physical interpretation, indicating a heterogeneous surface adsorption. The kinetic analysis reveals that the pseudo-first-order model can describe the adsorption process, indicating that surface reactions are dominant the rate-controlling step. The XPS spectra confirm the formation of Ca- and Mg-phosphate species on the ceramsite surface after adsorption, showing that phosphate removal occurs based on a synergistic mechanism involving physical adsorption and chemical precipitation.

The results of leaching tests indicate that the concentrations of heavy metals released from the ceramsite are well below regulatory limits, having its environmental safety for water treatment applications.

A fly-ash-based ceramsite was prepared using municipal sludge and furnace slag as auxiliary components for efficient phosphate removal in water. The ceramsite exhibited a high removal efficiency, a broad pH value adaptability, and a stable performance under complex water chemistry conditions via systematic optimization of preparation parameters and comprehensive adsorption studies. The phosphate removal mechanism was dominated due to the synergistic effect of surface adsorption and Ca/Mg-induced chemical precipitation. Moreover, the ceramsite showed a negligible heavy-metal leaching risk, indicating a good environmental compatibility. This study could provide a feasible approach for the large-scale resource utilization of fly ash and offer a promising adsorbent for phosphorus control in aquatic environments.

Cement production accounts for approximately 12% of China's total CO₂ emissions, having a significant challenge to achieving the national "dual carbon goals". Carbon capture, utilization, and storage (CCUS) represent a pivotal innovative technology for mitigating these emissions. However, conventional amine-based CO₂ capture requires an energy-intensive high-temperature desorption, hindering its industrial implementation in cement plants. Also, the limited utilization pathways for captured CO₂ pose another challenge for cement CCUS. Diethanolamine (DEA) offers a promising solution as it functions both as a CO₂ absorber and a cement additive. This dual capability enables a potential carbonation utilization of CO₂ absorbed DEA solutions without requiring the desorption step within cementitious systems. This study was thus to investigate the effect of CO₂-absorbed diethanolamine (DEAC) on the early hydration behavior and strength development of cementitious systems. The findings could propose a novel approach for low-energy CO₂ capture coupled with efficient in-situ utilization within cement industry.

Cement mortars with a water-to-cement ratio (W/C) of 0.50 were prepared with P·I 42.5 Portland cement (GB 8076) and ISO standard sand. The specimens were designated as REF, D0.1%C0%, D0.1%C0.02%, D1.0%C0%, and D1.0%C0.22%, respectively. DEA and its equivalent CO₂ admixture were added as percentages of cement mass. All associated cement paste mixtures were prepared at a W/C ratio of 0.3. DEAC was prepared by continuously bubbling CO₂ gas (≥99% purity) at a flow rate of 200 mL/min through a 5 mol/L DEA solution maintained at 40 ℃ until saturation was achieved. An eight-channel microcalorimeter recorded the hydration heat of cement paste specimens at 25 ℃ for 72 h. The phase composition of hardened cement pastes was determined by X-ray diffraction (XRD). The contents of bound water, CH, and CaCO₃ were analyzed by thermogravimetric analysis (TGA). The cumulative porosity and pore size distribution of hardened paste samples at 7 d were characterized by mercury intrusion porosimetry (MIP). The compressive strength was measured on mortar specimens at 1, 3 d and 7 d of curing in accordance with the standard GB/T 17671.

The hydration calorimetry results demonstrate that D0.1%C0.02% and D0.1%C0% both accelerate the hydration rate of silicate phases, as evidenced by an increased second exothermic peak rate, while leaving the induction period duration unaffected. Conversely, D1.0%C0% and D1.0%C0.22% significantly reduce the second exothermic peak rate. D1.0%C0.22% extends the hydration induction period to 240 min, while D1.0%C0% has a negligible effect on its duration. The XRD patterns and TG analyses reveal that the impact of DEAC on the cement hydration depends critically on its specific DEA and CO₂ dosage. At a low dosage (i.e., D0.1%C0.02%), a mild carbonation promotes a concurrent hydration of silicate and aluminate phases. However, a high dosage (i.e., D1.0%C0.22%) substantially inhibits early hydration of silicates. The MIP results indicate that DEAC and DEA both refine the pore structure of hardened cement paste. The pores below 20 nm are significantly reduced in D0.1%C0% and D0.1%C0.02% systems, aligning with their enhanced early hydration kinetics. This refinement also occurres in D1.0%C0% and D1.0%C0.22% systems despite inhibited silicate hydration. The results of compressive strength tests show that D0.1%C0.02% and D0.1%C0% can enhance mortar strengths at 1, 3 d, and 7 d, respectley. The strengths of D0.1%C0.02% systems can be increased by 8.4%, 10.2%, and 16.8% at these ages, respectively, primarily due to the DEA component with the weak carbonation contributing minimal additional enhancement. The 3-day and 7-day strengths of D1.0%C0.22% and D1.0%C0% systems both are increased (more significantly in the carbonated system), indicating a synergistic hydration-carbonation effect. However, the 1-day strength of D1.0%C0.22% system drastically is reduced by 52.2%, with silicates hydration inhibition by D1.0%C0% identified as a primary factor underpinning early strength reduction. According to the analysis of bound water content, calcium hydroxide (CH) content, porosity, and compressive strength relationships, a linear correlation between CH content and mortar strength is proposed. This demonstrates that silicate phase hydration kinetics can be modulated differently by DEAC and DEA formulations-fundamentally governed compressive strength development.

The addition of 0.1%DEA with 0.02% CO₂ (D0.1%C0.02%) as DEAC enhanced the flexural and compressive strengths of cement mortar at 1, 3 d, and 7 d. In contrast, the addition of 1.0% DEA with 0.22% CO₂ (D1.0%C0.22%) significantly reduced the 1-day strength. In D0.1%C0.02% system, the CO₂ component reacted with dissolved Ca²⁺ released from cement minerals to precipitate CaCO₃. This reaction promoted cement hydration, refined the pore structure of the hardened paste by reducing the volume of harmful pores, and facilitated a synergistic enhancement of hydration and carbonation. D1.0%C0.22% addition significantly retarded cement hydration within the first 24 h, primarily by inhibiting the dissolution of silicate phases and extending the induction period, leading to the reduced early strength. Although carbonation exacerbated the retardation of silicate phase hydration via DEA interaction, the hydration process recovered normal kinetics after 7 d.

The Faraday effect was discovered 180 years ago, but this phenomenon has been still utilized for practical applications as mentioned above. In particular, Tb³⁺-rich and Eu²⁺-rich oxide glasses are important for both fundamentals and applications. The Tb³⁺-rich glasses show a high transparency even in blue to ultraviolet region, so that the magneto-optical figure of merit is large enough to apply for an optical isolator. The Eu²⁺-rich glasses are ferromagnetic, so that they notably show a large Faraday effect. A new technique of glass formation such as containerless processing is effective to produce new glass compositions with further higher concentrations of rare-earth ions that are expected to exhibit a larger Verdet constant. Besides, the possible enhancement of Faraday effect based on plasmonics and Mie-tronics, i.e., the usage of localized surface plasmon resonance of metal nanoparticles and the Mie resonance of dielectric nanoparticles to increase the Verdet constant, becomes an important subject in the near future. With the development of high-power lasers, the demand for optical isolators that can operate in a wide wavelength range must increase. The oxide glasses have a promising application in such fields.