The up-conversion (UC) luminescence properties of natural sodalite (Na₈Al₆Si₆O₂₄Cl₂) co-doped with Europium and ytterbium (Eu³⁺ and Yb³⁺, respectively) was studied for the first time under excitation of near infrared reflectance (NIR) light. Cooperative energy transfer process was discussed as the possible mechanism for the visible up-conversion luminescence of Eu³⁺. The crystal structure of fluorescent powder was investigated using an X-ray powder diffraction system. The prepared phosphors radiate very strong red fluorescence with chromaticity coordinates of (0.661, 0.339) at 265 nm excitation, which consists of red light with higher purity at 611 nm due to Eu³⁺ (⁵D₀→⁷F₂), so it can be used as a red phosphor. The photo physics involved in this emission is explained.

Four ternary complexes [Ln₂(PIA)₂(acac)₂] (Ln=Sm (1), Eu (2), Tb (3), Dy (4)) were synthesized with isophthalic acid (H₂PIA, C₈H₆O₄), acetylacetone(Hacac, C₅H₈O₂) and Ln(NO₃)₃·nH₂O in ethanol solution. These complexes were characterized by elemental analysis, infrared (IR) spectra, and thermogravimetric analysis (TG). Their possible structures were proposed. In order to compare the luminescent properties between ternary complexes and corresponding binary complexes, the binary complexes [Ln₂(PIA)₃(H₂O)₄] and Ln(acac)₃(H₂O) (Ln=Sm, Eu, Tb, Dy) were also prepared. The fluorescent spectra of the ternary and binary complexes were determined at room temperature. The results show that all complexes displayed the characteristic emissions of rare earth center ions. The luminescent intensities of the ternary complexes (except the dysprosium complex) were stronger than that of the binary complexes, indicating that the synergistic sensitization effect had occurred for the center ions from the double ligands. These experimental results can be explained by the energy matching of the lowest triplet energy level T₁ of the two ligands (calculated from Gaussian theory) and the lowest excited state energy level of the central metal ions.

A high-flux T-zeolite membrane was prepared with a macromolecular substance with adjustable pore structure-1,2-bistriethoxysilyl ethane abbreviation (BTESE) on the surface of T-zeolite membrane synthesized via crystallization for 5 h. The properties of T-zeolite membrane were characterized by X-ray diffraction, scanning electron microscopy and pervaporation analysis. Meanwhile, the pervaporation performances of the BTESE modified membrane and the secondary crystallization membrane were compared. The results show that the thickness of the membrane modified by BTESE is only a half of the thickness of the secondary crystallization membrane. The flux of the modified BTESE membrane is 4.358 kg·m^-2·h^-1, which is twice greater than that of the secondary crystallization membrane. In addition, the acid resistance test shows that the BTESE modified membrane has a stable pore structure and a good separation performance under weak acid conditions at pH value of >4.

A series of La_0.6Sr_0.4Co_1-yFe_yO_3-δ (LSCF, y=0.2, 0.5 or 0.8) oxides with perovskite structure was prepared by sol-gel method, and then the corresponding hollow fiber membranes with different microstructures were fabricated through the phase inversion/sintering method. The influence of the coagulant and Co/Fe molar ratio on the microstructure and oxygen permeability of LSCF hollow fiber membranes was investigated. LSCF hollow fiber membrane with a dense thin outer surface and large numbers of finger-like channels was prepared by using a mixture of 70% (mass fraction) NMP and 30% ethanol as internal coagulation and deionized water as outer coagulation. The finger-like pores could greatly reduce the diffusion resistance, and thus improving the oxygen permeability. With the increase of temperature and the rate of helium sweeping gas, the oxygen permeation flux of LSCF hollow fiber membrane increases gradually. The Co/Fe molar ratio has an important influence on the membrane microstructure and oxygen permeation. The O₂ permeation flux increased with increasing the Co/Fe molar ratio. The oxygen permeation flux reached up to 2.81 mL·min^-1·cm^-2 at a helium sweeping rate of 120 mL·min^-1 and Co/Fe molar ratio of 4 at 950℃ (the test temperature of oxygen-permeable membrane).

Green synthesis of Mg-Al-CO₃ layered double hydroxides/calcite composite powders (LDH/Cal) via the acid dissolution and co-precipitation process was investigated in this paper. This method uses dolomite as a source of magnesium, calcium, and carbon dioxide with no CO₂ release in the process of preparation. LDH/Cal prepared under optimized conditions (acid dissolution temperature was 60℃, OH^-/[Mg²⁺+Al³⁺] mole ratio was 3.5∶1.0, Mg²⁺/Al³⁺ mole ratio was 3∶1, temperature and time of crystallization were 120℃ and 18 h, respectively) was characterized. LDH/Cal consists of LDH (39.5%) and calcite (60.5%). The calcite was regular and granular with a diameter of about 0.6 to 1.8 μm, and LDH contained well-defined plate-like particles with regular hexagonal shape, and sizes between 100 and 200 nm. The acid dissolution process of dolomite and the compound mechanism of LDH and calcite were discussed.

TiC/SiC coated natural flake graphite was used as a new carbon source of low carbon Al₂O₃-C refractories which was prepared by self-propagating high-temperature synthesis (SHS) using Ti, Si and GF as raw materials. The phase composition of the products was characterized by X-ray diffraction and the microstructure as well as the element distribution were studied via a scanning electron microscopy coupled with an energy dispersive spectroscopy. The effects of the amount of graphite on the reaction were studied. The results show that the maximum amount of GF added is 38.6% (mass fraction) under a self-sustained combustion wave, and a continuous, complete TiC-SiC coating layer with a uniform thickness (about 360 nm) is synthesized on the GF surface. The effects of the amount of the coated graphite on the properties of low carbon Al₂O₃-C refractories were invetigated. The results revel that the Al₂O₃-C refractory shows the optimal properties when 3% (mass fraction) coated graphite is used: the lowest apparent porosity (12.9%), the highest cold modulus of rupture (20.7 MPa), and the thickness of oxide decarburization layer and the erosion depth of slag are reduced by 41.8% and 57.1%, respectively.

Ca₅Mg₄(VO₄)₆ microwave dielectric ceramic was prepared by a solid-phase reaction method. Mg element in Ca₅Mg₄(VO₄)₆ ceramic was substituted by Co element in order to improve the microwave dielectric properties. The phase composition and microscopic morphology of the ceramics were determined by X-ray diffraction and scanning electron microscopy. Also, the internal laws of the microwave dielectric properties were analyzed via theoretical calculations, such as bond energy. The formation of solid solution after Co substitutioncan decrease the sintering temperature. The density dominates the change of ε_r at a higher relative density. However, ε_r is mainly affected by the ion polarizability per unit volume at a lower relative density. The grain size reduction caused by the substitution is beneficial to the promotion of the Q×f value. τ_f is closely related to the bond energy and changes with the bond energy of the V—O, which is the maximum bond energy in ceramics. Ca₅Mg₃Co(VO₄)₆ ceramic has the optimum microwave dielectric properties (i.e., ε_r=9.65, Q×f=54 685 GHz, and τ_f = -55.3×10^-6℃^-1).

The ZnO-A1₂O₃-MgO-TiO₂-SiO₂-Fe₂O₃ linear ceramic resistance were prepared by solid state sintering method. The effect of Fe₂O₃ doping on the microstructure, impedance, temperature-resistance characteristics and impedance-frequency characteristics was investigated. The results show that the ZnO linear ceramic resistance doping with 0.75% (mass fraction) Fe₂O₃ has the optimum comprehensive performance. This resistance synthesized has nonlinear coefficient of 1.12, and resistance temperature coefficient of -8.23×10^-3/℃.

A pressure rapid sintering process of tetragonal zirconia ceramics was proposed. The effects of sintering parameters (i.e., temperature, voltage, current and pressure) on the density, microstructure and phase composition of zirconia were investigated. The process superimposed a flash burning effect based on hot pressing sintering, and the high-temperature conductive zirconia was instantly densified and sintered at a high electric field strength. The results show that the pressure-assisted flash sintering process involves the advantages of hot pressing sintering and flash sintering. Zirconia powder was used as a raw material to simplify the green pressing process. Low temperature and instantaneous flash firing inhibit the high-temperature phase transformation of zirconia. Hot pressing in sintering process ensures the diffusion and flow of zirconia powder and enhances the density.

Boron carbide matrix composites containing boron carbide (B₄C), titanium diboride (TiB₂) at 20% (mass fraction) and 30%, and titanium carbide (TiC) were fabricated at 2 130℃ using a pressure-less sintering method. Different amounts of TiB₂ and TiC particles were added to B₄C. TiB₂ content was chosen as the main variable to study the effect on the composites. The density, hardness, bending strengths and fracture toughness measurements were performed to obtain the physical and mechanical properties of the samples. The results indicate that by adding 30%TiB₂ sub-micron particles at 2 130℃, the bending strength and fracture toughness of 277.6 MPa and 5.38 MPa·m^1/2 were obtained for the composite. Particle pullout and crack micro-bridging play an effective role in toughening the composite ceramics. The main toughening mechanisms of the B₄C-TiB₂ composites are noted to possess microcrack and crack deflection toughening owing to the residual stresses resulting from the mismatch of the thermal expansion coefficient between TiB₂ and B₄C.