A trampoline phononic crystal model was proposed based on the trampoline effect. The band structure and eigenmodes of trampoline phononic crystals were calculated by the finite element method. Compared with the conventional phononic crystals, the height of trampoline phononic crystal cylinder was selected to investigate the rainbow trapping effect. For the trampoline phononic crystals with different column heights, 16 trampoline phononic crystal cells were classified in the form of single number as well as ordered and random completely disordered arrays, respectively. The corresponding transmission loss curve was determined, and the influence of array combination form on the rainbow trapping effect was analyzed. Furthermore, three slightly disordered trampoline phononic crystal arrays were designed to analyze the influence of disorder on the rainbow trapping effect. The results show that the band gap width of the new trampoline phononic crystal is 2.1 times greater than that of the conventional phononic crystals. The ordered arrangement of trampoline phononic crystals has an obvious rainbow trapping, while the completely disordered arrangement has a strong 'inverse rainbow trapping'. The attenuation ability of the three slightly disordered trampoline phononic crystal arrays to the excitation signal is basically the same as that of the orderly arrangement, indicating that the designed trampoline phononic crystal is robust to the slightly disordered arrangement of the array. This paper provides a reference for the directional design of rainbow trapping phononic crystal arrays with attenuation frequency domain and maximum attenuation amplitude.

The coloration mechanism of different glazes in Na₂O-MgO-CaO-Al₂O₃-SiO₂-P₂O₅ multi-element glaze system was revealed via investigation of the microstructure and crystallization behavior of glaze melts with different iron oxide contents. The results show that the phase separation in glaze is improved by calcium phosphate, which plays an important role in glaze color. Fe³⁺ ions exist at a lower iron oxide content. The chemical color of Fe³⁺ ions results in a dark-green glaze. The phase separation effect of glaze layer increases and the phase interface becomes larger with the increase of iron oxide content. Due to multiple scattering and consumption by massive phase interfaces, the incident light is absorbed and a black glaze appears at an excessive iron oxide content. α-Fe₂O₃ nanocrystals can be precipitated from silicate glaze, and glaze surface appears red color. A needle-like array structure can be formed in the growth of α-Fe₂O₃ nanocrystals, interfering with an incident light and resulting in silver-gray glaze. It is indicated that the interaction of chemical color and structural color induces different color rendering effects of glaze with the change of iron oxide content.

AlN crystal is a typical brittle and difficult-to-process material. To prepare AlN crystal substrates with a high efficiency and a high quality, slurries with different chemical compositions were designed to lap AlN crystals, and the mechanism of chemical action-assisted material removal was investigated by laser confocal microscopy and X-ray photoelectron spectroscopy. The results show that the alkaline slurry is beneficial to obtaining the optimum lapping results, the material removal rate is 23 μm/h, and the surface roughness (R_a) is 122 nm. The diamond abrasive particles in the slurry have a good dispersibility in alkaline environment. The alkaline solution can corrode the crystal surface, form a metamorphic layer containing basic aluminum salts, and cause some changes in the surface morphology. In the lapping interface, the metamorphic layer produced by chemical etching on the surface of AlN crystal is more conducive to the mechanical removal of abrasive particles, which can lay a foundation for improving the lapping efficiency and quality. The result obtained can provide a reference for optimizing the ultra-precision processing technology of AlN crystals.

The comprehensive utilization of bulk solid waste is of great significance to the realization of carbon neutrality and standards. This review represented recent work on the utilization of solid wastes for preparing foamed ceramics by in-situ foaming process. Especifically, solid waste raw materials, foaming agents and additives, preparation process as well as the performance and application of foamed ceramics were discussed. In addition, the interaction between foaming behavior and sintering process was also revealed, the in-situ pore forming sintering mechanism of foamed ceramics was described, and the existing problems and future development direction were summarized to provide a reference for promoting the further comprehensive utilization of solid waste for preparing foamed ceramics.

Hydroxy aluminum polycation was firstly prepared with AlCl₃·6H₂O and NaOH as raw materials, and then Al-pillared montmorillonite was prepared with hydroxy aluminum polycation as alumina source. A montmorillonite-based ceramic was fabricated via ball milling and hot pressing with Al₂O₃ and Al(OH)₃ as alumina sources. The effect of hot-pressing temperature on the mullitization and mechanical properties of montmorillonite-based ceramic was investigated. The results show that the mechanical properties of montmorillonite-based ceramics are improved by adding three kinds of alumina sources at the hot-pressing temperature of 1 100 ℃. The optimum flexural strength and fracture toughness of Al-pillared montmorillonite-based ceramics at 1 300 ℃ (i.e., 118.07 MPa and 2.30 MPa·m^1/2) can be obtained, which are increased by 41.0% and 74.2%, compared with original montmorillonite ceramics.

A ratiometric fluorescent probe (CQDs/Eu³⁺) was constructed with carbon quantum dots (CQDs) and europium ions (Eu³⁺) as fluorophores for the detection of ciprofloxacin (CIP). At excitation at 395 nm wavelength, CQDs/Eu³⁺ has an intense blue fluorescent peak at 459 nm, and a weak red fluorescent peak at 616 nm in the presence of CIP. The fluorescence (FL) intensity of CQDS at 459 nm is enhanced based on the antenna effect. The major factors like ratio of CQDs and Eu³⁺, response time and stability were optimized, The results show that the ratio fluorescent probe has a specific recognition ability for CIP. And there is a linear relationship between the fluorescence intensity ratio (F₄₅₉/F₆₁₆) and concentration of CIP (0-7×10^-6 mol/L), and the lowest detection limit for CIP is 0.3×10^-6 mol/L. This probe can be used for the detection of CIP in milk under the addition of CIP.

Crystalline and noncrystalline materials activated with 3d transition metal ions (TMIs) featured by rich spectral characteristics are widely used as phosphors as well as laser gain media. In recent years, the broadband NIR LED is regarded as an ideal miniaturized light source for NIR spectrometers, which can be easily integrated in portable electronic devices in food security and biomedicine. The near-infrared (NIR) phosphors activated by TMIs like Cr³⁺ ions are considered as a key stage in the development of highly efficient broadband NIR LEDs. Unlike the parity forbidden f-f transitions of trivalent rare-earth ions, the d-d transitions of 3d TMIs exhibit large bandwidth and tunable emission wavelengths due to the intense coupling with the surrounding crystal field. At present, materials doped by TMIs except Cr³⁺ ions are rarely explored for NIR applications. In this review, the spectral characteristics associated with the d-d transition of 3d TMIs were elaborated, and recent development on TMI activators and phosphor matrix for a broadband NIR photoluminescence was represented. In addition, this review also provided a brief summary for the factors that need to be considered in the design of broadband NIR phosphors. This review is expected to offer useful guidelines for the development of advanced NIR pc-LEDs.

SiC ceramics are difficult to be directly processed into large and complex components due to their high brittleness, high hardness and high wear resistance. Therefore, joining technology is one of the developed methods to facilitate the engineering application of SiC ceramics. Among various joining methods, the joints obtained by the joining method using SiC as a major phase of the joining layer have some advantages like high joint strength, low joint stress, radiation resistance, chemical corrosion resistance and high temperature resistance, thus becoming the key technologies for SiC ceramic joining, i.e., nano-infiltrated transient eutectoid phase joining (i.e., NITE phase joining), silicon-carbon reaction joining (i.e., Si—C reaction joining) and precursor joining. This review represented three kinds of SiC ceramic joining technologies above using SiC as a major phase of the joining layer from the aspects of joining mechanism, joining process, joint composition, microstructure and joining strength. The advantages and deficiencies of the three kinds of joining technologies were analyzed and compared. In addition, the future development was also prospected.

Investigation on 3D printing of silica ceramic cores is crucial to the development of aviation level in China, but the related problems are high-temperature softening and structural anisotropy. Silica ceramic cores were fabricated by DLP light curing 3D printing technology using fused silica powder as a raw material and mullite powder as a modifier. The results show that the ceramic cores have a layer-packed anisotropic structure. The addition of a small amount of mullite powder promotes the sintering densification of ceramic powder and diffusion binding between printing layers. As a result, the structural anisotropy of ceramic cores is relieved, and the flexural strength is enhanced and tended to isotropy. For ceramic cores with 3% mullite powder, the high-temperature flexural strengths in horizontal and vertical printing are up to 18.5 MPa and 16.3 MPa, respectively, which can satisfy the demands for hollow blade casting.

3C-SiC nanowires were synthesized in Ar atomosphere via Co nanoparticle catalytic reaction with expanded graphite and silicon powders as raw materials and Co(NO₃)₂·6H₂O as a catalyst precursor. The effects of reaction temperature and catalyst addition on the formation of SiC nanowires were investigated. The phase composition and microstructure of the as-prepared products were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The optoelectronic property of as-prepared 3C-SiC nanowires was analyzed. The results show that Co catalyst promotes the growth of 3C-SiC nanowires and decreases the complete reaction temperature and the formation temperature. 3C-SiC nanowires could be synthesized at 1 573 K for 3 h using 3.0% Co as catalysts at C/Si molar ratio of 1∶1. The formed 3C-SiC nanowires are approximately 50-60 nm in diameter and tens micrometers in length. According to the results by the first-principles calculation, the activities of the reactants are increased via dwindling the bonding strength of C=C, Si—O and C—O bonds. The room-temperature PL spectra indicate that the as-synthesized 3C-SiC nanowires have a special emission at 307 nm (4.04 eV), which could be used as a potential material for optoelectronic nanodevices.