Silver nanoclusters (Ag-NCs) with a small number of silver atoms or ions have discrete energy bands, thus exhibiting a size-dependent tunable emitting behavior with a high quantum yield. The Ag-NCs can be used as desirable sensitizers for rare-earth element ions to achieve an enhanced and tunable emission for diverse applications. Glasses are desirable matrixes to disperse and stabilize Ag-NCs due to their high transparency and excellent chemical/thermal stability. This review represented the preparation and control of Ag-NCs dispersed glasses, the luminescent properties of Ag-NCs and their sensitization for rare-earth element ions as well. The applications of Ag-NCs and rare-earth element ions co-doped glasses in a white and tunable light emission and solar cells were described. Besides, the problems encountered in current studies and the corresponding possible solutions were also discussed.

The effect of alumina (Al₂O₃) on the chemical durability of borosilicate glasses, 70SiO₂-(20-x)B₂O₃-_xAl₂O₃-10Na₂O, x=0, 5, 10, 15 and 20 (molar fraction), in water, HCl and NaOH aqueous solutions, was investigated via liquid resistance tests. The chemical stability of aluminoborosilicate glass was discussed based on the glass structure, and the mechanism of chemical attack in different solutions was proposed. The results show that a significant enhancement in the chemical durability in water, HCl and NaOH aqueous solutions occurs after the incorporation of Al³⁺ into the oxide glass network. The structural analysis indicates that the relatively low chemical durability of the glass as x=0 is correlated to the presence of BO₄ with three and four non-bridging oxygen (NBO) in the melts. Consequently, the glass is eroded more quickly during the attack of the aqueous solutions, resulting in a porous glass surface. The chemical durability can be improved due to the addition of Al₂O₃ into the glass network, suppressing the formation of BO₄.

The morphology and structure of fiber precursors before and after acid leaching were characterized by scanning electron microscopy (SEM) and infrared spectroscopy (IR), and the Na⁺ leaching process was characterized by inductively coupled plasma spectrometry (ICP). The effects of hydrochloric acid concentration, leaching temperature and time on the leaching rate of Na⁺ and mechanical properties of the fiber precursor were investigated. The Na⁺ leaching rate reaches 85% after leaching in 3 mol/L hydrochloric acid solution for 12 h at 90℃_. The maximum strength retention rate of the fiber after leaching can be obtained when the concentration of hydrochloric acid is 5 mol/L. In this case, Na⁺ ions in the fiber are replaced with H⁺ ions in hydrochloric acid during the acid leaching process, whereas hydroxyl group is further polymerized and dehydrated, thus strengthening the glass network during the heat treatment process and improving the fiber strength.

Fluorescent glass-ceramic (GC) is an opto-functional composite material consisting of crystalline and amorphous phases. Low-temperature co-sintering method is an effective technical approach that can be used to regulate the ordered and disordered structures in this composite material, thus enabling "bottom-up" and "on-demand" design. In this review, material systems of fluorescent GC prepared by the low-temperature co-sintering method were outlined, and the structural manipulation, structure-property relationship and the improvement of luminescent property were emphasized. Recent applications in advanced optoelectronic devices were represented, and some possible aspects in the future development were discussed, such as development of novel material systems, interfacial chemical bond effect and interfacial ion diffusion mechanism. Moreover, optical simulation techniques and exploration of novel applications were elaborated.

Recent work on the characterization of nanoparticles crystallization process in glassy matrix by in-situ transmission electron microscopy (TEM) was represented. In-situ TEM technique as an effective tool can determine the structural dynamics of nanoparticles in real-time to clarify and optimize their structures and properties. We summarized the dynamic process stages of glass ceramics growth, i.e., phase separation, nucleation, crystallization and coalescence. The electron beam (E-beam) and thermal effects on the nanoparticle growth process in glassy matrix were discussed. In addition, the opportunities and challenges of in-situ TEM applied to glass ceramics were also proposed.

Whispering gallery mode (WGM) microcavity is an efficient laser resonator, which can trap light in a rather small space, achieve a high light energy density and greatly enhance a light-matter interaction. Among numerous materials, rare-earth (RE) element ions doped nanocrystals-in-glass composite (NGC) can be used as an ideal candidate for WGM microcavity lasers due to its superior optical properties of crystals and outstanding mechanical processing properties of glasses. However, a few works on WGM microcavity lasers based on RE-doped NGC are reported. In this review, the basic principle and characteristic parameters of WGM microcavity were briefly described, and recent development on the WGM microcavity lasers made of RE-doped NGC was summarized. In addition, the corresponding future development was also forecasted.

Glass is widely used in sealing and connection of various optoelectronic devices due to its favorable heat resistance, excellent electrical insulation, and adjustable expansion coefficient. This review briefly represented the interaction mechanism between sealing glass and substrate materials, such as glass, ceramics, metal, silicon wafer, etc.. Besides, recent development on sealing glass in new energy devices, photoelectronics and other applications, such as silicon solar cell electrode, organic light-emitting diode, solid oxide fuel cell, was described. In addition, the critical research and key issues of sealing glass were also discussed. The related applications and future development of sealing glass were summarized and prospected.

Chalcogenide (ChG) fibers become the only nonlinear fibers for midwave- and longwave-infrared supercontinuum (SC) generation due to the high transmittance in infrared region and high nonlinearity. The results of work on mid-infrared SC in the last five years were reported. This review represented recent development on ChG fibers, including experimental SC generation of step-index, micro-structured & multi-clad chalcogenide fibers and all-fiberized SC sources.

Effect of temperature rising inhibitor (TRI) on the hydration process of cementitious materials containing fly ash and the performance of concrete was investigated. The hydration process of cementitious materials was examined as a function of the contents of fly ash and TRI. The adiabatic temperature rise, mechanical properties and drying shrinkage of concrete derived from the cementitious materials and TRI were also evaluated. According to the hydration heat of the binder pastes, it was revealed that the addition of TRI lowers and delays the exothermic peaks more significantly in the presence of fly ash. The phase composition and microstructure of the hardened paste indicate that TRI mainly inhibits the hydration degree of the cementitious materials in the first 7 days. The presence of TRI slows down the adiabatic temperature rising rate, reduces the early strength of the concrete and increases drying shrinkage of the concrete.

A self-healing agent that can bind aggressive seawater ions and accelerate the healing process was developed, which was encapsulated as artificial aggregates. The closure ratio of a 400-μm-wide crack is 80% after self-healing for 24 h in seawater by using the self-healing agent, which is 4 times greater than that in referenced specimens. The reaction products formed at the crack mouth are mainly brucite and calcite, while in the aggregates intersected by the crack there are portlandite, calcite, Friedel's salt, ettringite and hydrotalcite, indicating that the aggressive ions can be bound by the self-healing agent. The mineralogy and distribution characteristic of the reaction products are dependent on the diffusion of the ions dissolving from the agents and the thermodynamic equilibrium constants of the reaction products.

Macrocell corrosion occurs in concrete structures universally, which accelerates the deterioration of concrete structures, when combined with microcell corrosion. In recent years, the durability problem caused by macrocell corrosion becomes more prominent with the advancement of engineering construction in China, thus demanding the corresponding protection. Nevertheless, there are many factors influencing the corrosion of microcell and their causes are relatively complicated, thus becoming a great challenge in the field of corrosion science and technology. This review offered an overview on the progress and prospects of macrocell corrosion of steel bars in concrete, including theory of the mechanism and influencing factors. In addition, the future research direction of macrocell corrosion was also discussed.

The corrosion state of composite binder mortar with metakaolin (MK) in chloride environment was investigated by measuring corrosion potential, linear polarization and cyclic potentiodynamic polarization. The relationships among different electrochemical parameters were analyzed. In chloride environment, the corrosion potential of the reinforcing steel in the composite binder mortar increases, the corrosion rate decreases and the pitting corrosion resistance enhances with increasing the MK content as the MK content is < 30% (accounting for total mass of MK and cement). The corrosion current density and corrosion potential are correlated to composite binder mortar. The degree of pitting corrosion of the reinforcing steel in the composite binder mortar is well reflected by main electrochemical parameters of cyclic potentiodynamic polarization. The presence of MK modifies the pore structure and reduces the permeability coefficient of the chloride in the composite binder mortar. The depassivation time of the reinforcing steel and the expected cracking time of reinforcing steel cover both are prolonged when the composite binder mortar is added.

Sulfur oxidation characteristics of sulfur oxidizing bacteria under different substrates and the mechanical properties and microstructure of mortar samples were investigated. The growth concentrations of sulfur oxidizing bacteria are different under different substrates, i.e., the corresponding growth concentration decreases from high to low in an order of Na₂S₂O₃, Na₂SO₃ and Na₂S. The natural oxidation and biological oxidation both occur in the transformation of SO₄^2- by the sulfur oxidizing bacteria under different substrates. S₂O₃^2- can be transformed to SO₃^2- through SseA enzyme and then to SO₄^2- through Soe enzyme. The swelling gypsum content of mortar sample under Na₂S₂O₃ substrate is lower than that under Na₂SO₃ substrate. This is because SO₄^2- concentration of natural oxidation of Na₂SO₃ is greater than that of the biological oxidation, thus leading to a higher reaction rate and a stronger corrosion effect. The compressive strength and mass change rate of the mortar samples under Na₂S₂O₃ substrate are 10.4% and 1.04%, respectively. The change rate of compressive strength and mass of the mortar samples under Na₂SO₃ substrate are -12.9% and 1.44%, respectively. Combined with the mineral composition analysis results, it is indicated that the gypsum content of the samples under Na₂S₂O₃ substrate is lower than that of the samples under Na₂SO₃ substrate, while the mortar samples are eventually deteriorated, due to the expansive force of a large amount of gypsum after 75 d and 45 d.

¹H low-field nuclear magnetic resonance instrument was used to continuously monitor the changes in the transverse relaxation time of white cement with silica nanoparticles with different sizes (i.e., 15 nm, 50 nm and 100 nm) from adding water to hydration for 72 h. The effect of silica nanoparticles with different sizes on the hydration process of cement was investigated. The setting time of cement paste was measured using the Vicat apparatus. The results show that the crystal nucleation of silica nanoparticles can affect the early hydration process of cement, thus breaking the flocculation structure of cement paste due to the physical adsorption and pozzolanic reaction, reducing the number of macropores, and improving the uniformity of cement paste. In addition, the smaller the silica nano particles is, the less the free water content in hydration process and the shorter the setting time will be.

The constitutive behavior of hybrid basalt-polypropylene fiber-reinforced concrete (HBPRC) with different matrix strengths was investigated. The influences of basalt fiber (BF) and polypropylene fiber (PF) on the constitutive behavior and energy conversion relationship of the concrete were analyzed. The results show that the addition of BF and PF with an appropriate content can improve the ductility and strength of the concrete, but the influence of BF and PF on the elastic modulus is more complicated. In addition, the presence of BF and PF, especially their mixtures, significantly reduces the elastic strain energy release rate, increases the dissipation energy and thus improves the ductility and toughness of the concrete. Comparatively, BF is more conducive to improve the strength of the concrete, while PF mainly inhibits the expansion and penetration of macro-cracks in the concrete. Based on the statistical damage theory and dissipation energy, a constitutive model of HBPRC was proposed.

High-temperature high-pressure (HTHP) working conditions of oil-well cement paste alter the expansive mechanism of MgO expansive agent, thus significantly accelerating the expansion speed and increasing the ultimate expansion. The free expansion rate of shrinkage-compensating pastes with MgO expansive agent at different contents was investigated. The microstructural characteristics, including morphology and porosity, were evaluated to reveal the expansive mechanism of MgO expansive agent in HTHP environment. It is indicated that the shrinkage of oil-well cement paste can be compensated by admixing MgO expansive agent at proper contents and reactivity. At 150℃ and 20 MPa, S-type (220 s) MgO with a relatively low reactivity is recommended and its dosage is less than 4%. At HTHP, the migration of Mg²⁺ from MgO particles is accelerated. Besides the formation of expanding mircocracks, Mg(OH)₂ crystals also are interlocked with tobermorite crystals as a hydration product of cement, thus enlarging their gap and causing an extraordinary expansion, compared to the expansive binder cured at normal temperature and pressure.

In order to achieve particle segmentation and extract morphological information from the images of brick-containing recycled coarse aggregate bulk in the stacked state, an image-based method was proposed. Based on the differences in hue and distance between particles of the recycled concrete and crushed brick aggregate, the model was incorporated into the threshold segmentation and distance transformation, thus optimizing the watershed segmentation algorithm. It is indicated that the optimized segmentation algorithm could be used to effectively extract the contours of individual aggregate particles and calculate their morphological information, such as aggregate gradation, proportion of each aggregate, flakiness ratio and sphericity.

BSE-Raman was used to investigate in-situ Raman spectra of hydration products and their spatial distribution profiles. It was found that the in-situ structural information of the silicon-oxygen tetrahedral Q¹, Q² and Q³ chains of C-S-H could be readily obtained, while the hydration products could be accurately identified. All the hydration products with different morphologies exhibited multiple characteristic peaks of chemical bonds of the hydration products. Therefore, it was concluded that the cement hydration products were mixed at nanometer scale. The pom-shaped hydration product had a skeleton consisting of C-S-H and ettringite. Due to its ability of quick and accurate in-situ identification of different phases, BSE-Raman has broad prospects in the microstructural characterization of cement-based materials.

Considering tunnel engineering conditions, we proposed a blockage model of tunnel drainage pipe in the non-karst area based on the calculation of calcium carbonate fouling rate. The model was used to calculate blockage time of the drainage pipe for existing and under construction tunnels. For existing tunnel, the calculation result of the model is close to the measured results, thus verifing the validity of the model. For under construction tunnel, in order to prevent the drainage pipe from being blocked within 20 years, Ca²⁺ leaching rate of primary support concrete subjected to 6 mol/L NH₄Cl solution eroding for 14 d should not exceed 0.032%.

In view of the large deviation of the effect of organic steel corrosion inhibitor in simulated pore solution and concrete, a dry-wet cycles test apparatus for accelerated evaluation of organic steel corrosion inhibitor was developed based on the concrete simulated pore solution and the controllable temperature and humidity. Four test systems were used to examine acceleration effects and test deviations of steel corrosion. The deviation of the test results of the organic steel corrosion inhibitors is significantly minimized via accurately controlling the test environment parameters and optimizing the acceleration systems. The results of the steel bars in the simulated pore solution and the concrete have a stronger correlation. Also, organic steel corrosion inhibitor, such as imidazoline, carboxylic acid amine and amino alcohol, effectively inhibits the rapid corrosion of steel bars under the condition of dry-wet cycles in chloride salt environment.

Siliceous components with different crystalline states (i.e., crystalline silica and amorphous silica fume) were used to adjust the content of free calcium oxide (f-CaO) in regenerated binding materials (RBMs). The effect of siliceous components on carbonation reactivity, mechanical properties, and microstructural characteristics of the final products was investigated. The results indicate that the matrix stability of the RBMs prepared with two siliceous components is significantly enhanced after carbonation. The compressive and flexural strengths of RBMs prepared with silica are 73.1 MPa and 21.0 MPa, respectively, and calcium carbonate crystals formed through the carbonation reaction are mainly vaterite and calcite. The compressive and flexural strengths increase to 106.3 MPa and 25.3 MPa at increment rates of 45.52% and 20.55%, respectively, when silica fume is used to prepare RBMs. In this case, calcium carbonate crystals are mainly vaterite, with a small content of calcite and aragonite. The improvement in the mechanical properties of RBMs with silica fume is due to the high carbonation reactivity, high degree of carbonation and dense structure.

The dispersion and orientation of steel fibers in the matrix have a significant impact on the mechanical properties and durability of steel fiber concrete (SFC). Some factors affecting the dispersion and orientation of fibers in SFC were summarized in terms of mixing proportion, rheology of the mixtures, construction technology and element shape. The results showed that the distribution characteristics of the fibers were affected synergistically by various factors before the mixtures were formed and hardened. Moreover, the distribution of steel fibers was optimized accordingly under different working conditions. There were three types of poor dispersion of steel fibers. Besides, three approaches were used to improve the orientation of steel fibers based on the construction technologies and the element shapes. In addition, some problems in steel fiber distribution characteristics and possible future research direction were also discussed.

The properties of cement concrete at low atmospheric pressures (LAP) were reviewed, including the foaming performance of air-entraining agent solution, air content and pore structure of concrete, concrete strength and concrete shrinkage. The effective power of the concrete mixer at LAP was reduced, so that the mixing quality of fresh concrete was adversely affected. The effect of LAP on the air content and pore structure of concrete was dependent on the type of the air-entraining agent. LAP has little effect on the air content and pore structure of concrete in the presence of a good air-entraining agent and the maintaining of mixing quality control. Moreover, LAP can detrimentally affect the mechanical and shrinkage properties of concrete. However, the mechanical properties of the well-cured concrete cannot be deteriorated at LAP. In addition, the problems mentioned in the literatures and the corresponding solutions were also discussed.

As an important construction material of offshore reef infrastructures, coral concrete becomes one of recent popular research aspects. Compared to aggregates derived from terrigenous rocks, coral aggregates are unique because of their mineral composition, pore structure and particle morphology. Coral aggregate concretes are different from those made of ordinary aggregates in terms of mixture proportion design, static/dynamic mechanical properties and durability, while they are similar to lightweight aggregate and recycled aggregate concretes. Meanwhile, the properties of coral concretes are also affected by the type and volume fraction of fibers. In addition, the development of coral concretes is gradually extended from a material level to a structural level. Appropriate modification is of great significance to extend the service life of the structures in offshore environment. In this review, the problems encountered in these modification processes and the corresponding potential solutions were discussed.

The X-ray CT in-situ tensile test of 2.5D-SiC_f/SiC composites was conducted to reveal the damage evolution and failure mechanism of the ceramic matrix composites. The CT data of the materials during the loading process and failure fracture were obtained. A deep learning-based image segmentation method was used to propose a three-dimensional visualization model of the internal damage of the composites, and the number, volume, spatial distribution and spatial angle of the microcracks generated due to the stretching were analyzed. At high loads, the tensile microcrack volumes are 0-5.3×10^-4 mm³, the fracture microcrack volumes are 0-2.2×10^-4 mm³, and the proportion of the microcracks with spatial angles of about 0° and 45° is relatively high. Meanwhile, the microcracks are closely correlated to the pore distribution. According to the results by fracture damage analysis, the tensile damage process of 2.5D-SiC_f/SiC composites includes matrix cracking, fiber fracture, fiber pull-out and interface debonding. The fiber pull-out lengths are in the range of 16.02-250.32 μm, and the average length is 88.26 μm. It is indicated that the image segmentation method based on deep learning could offer an effective way to reveal the mechanism of material damages and evaluate the degree of the damages.

Collophanite fluorapatite particles were prepared as seed crystals with Ca²⁺ and F^- ions, which were used to deeply purify low-concentration soluble inorganic phosphorus in water. The effects of combined reactants, reactant concentration, solution pH value and coexisting ions on the removal efficiency of phosphorus in water were investigated. To characterize the properties and clarify the mechanism of collophanite to remove soluble phosphates in water, the samples before and after pickling and phosphorus removal were characterized by scanning electron microscopy, transmission electron microscopy, thermoanalysis and Fourier transform infrared spectroscopy. Collophanite fluorapatite with calcium and fluorine exhibits the maximum phosphorus removal performance. The addition of Ca²⁺ ions significantly enhances the phosphorus removal efficiency, and F^- ions with a low concentration have a slight effect on the phosphorus removal efficiency. Therefore, F^- ions can be replaced by Ca²⁺ ions. When the initial concentration of phosphorus is 2 mg/L, pH value is > 6, and Ca²⁺ ions concentration is > 30 mg/L, the residual phosphorus concentration after the treatment is lower than 0.05 mg/L, thus meeting the Class Ⅱ standard of environmental tuality of water resource.