To get a dielectric material with a high dielectric permittivity and suppressed dielectric loss, nano-Ag with a particle size of 20 nm and Ag@TiO₂ core-shell particles with diameters of approximately 70–120 nm were embedded in polyvinylidene fluoride (PVDF) to fabricate nano-Ag/Ag@TiO₂/PVDF composites. After being modified by nano-Ag with 3 vol% optimal amount, the relative permittivity (ε _r) at 100 Hz of 50 vol% Ag@TiO₂/PVDF composites was 61, and the dielectric loss can be suppressed to 0.04, almost 96.4% lower than that of unmodified composites, and a higher frequency stability of both ε _r and loss has also been found. The underlying mechanism of the reduced loss was attributed to Maxwell-Wagner polarization and the Coulomb blockade effect caused by the introduction of a small amount of nano-Ag, which will block the movement of electrons between metal nanoparticles and composites. The space charge polarization and conductance loss are weakened at lower and higher Ag@TiO₂ filling ratios, respectively, thus leading to a very low loss of the composites.

C₃N₄, C₃N₄@Ti₃C₂ and W₁₈O₄₉@C₃N₄@Ti₃C₂ hollow spheres were successfully prepared by using SiO₂ template followed by gradual deposition method. The degradation of phenol solution and photolysis ability were tested to characterize its photocatalytic activity. Compared with the single-shelled C₃N₄ and C₃N₄@Ti₃C₂ hollow spheres, double-shelled W₁₈O₄₉@C₃N₄@Ti₃C₂ hollow spheres possessed larger surface area and fast charge separation efficiency, exhibiting about 8.9 times and 4.0 times higher H₂ evolution than those of C₃N₄, C₃N₄@Ti₃C₂ hollow spheres, respectively. The photocatalytic mechanism of the W₁₈O₄₉@C₃N₄@Ti₃C₂ hollow spheres were carefully investigated according to the results of morphology design and photoelectric performance. A Z scheme mechanism based on the construction of heterojunctions was proposed to explain the improvement of photocatalytic performance. This new charge transfer mechanism appears to greatly inhibit the recombination of electrons/holes during the charge transfer process, while maintaining its strong hydrogen reduction ability, resulting in a higher photocatalytic performance.

A two-dimensional geometric model is developed for a polymer electrolyte based on the liquid water penetration mechanism in the membrane electrode assemblies under the action of capillary pressure. The effects of the diameter, number, and distribution of cracks in the micro-pore layers (MPLs) of the modeled MEA on the performance of the PEMFC are simulated to investigate the influence of mass transfer across the membrane. The results indicate that liquid water in the catalyst layer (CL) of the MEA can be discharged to gas channels through the cracks in MEA under the action of capillary pressure, thereby alleviating the flooding in the CL and enhancing the diffusion of oxygen to the CL. When the proportion of the total area of cracks in the active area of the MEA was 8%–12%, crack diameter was 20–30 µm, and cracks were distributed uniformly. MEAs with and without cracks were prepared, fuel cells were assembled, and their performance was measured. The effects of cracks on mass transfer were then verified. This study helps prepare MEAs with controllable cracks.

Titanium diboride ceramic was produced via spark plasma sintering (SPS) using finer TiB₂ powder made by high-speed planetary ball milling. The effects of ball milling parameters on the composites and particle size of TiB₂ powder were investigated. It was shown that the average particle size of TiB₂ powder decreased from 5.8 to 1.59 µm and the wear rate of WC balls was 1.58 wt%, when the ball-to-powder weight ratio (BPR), the rotary speed and milling time and were 10:1, 600 rpm and 20 min, respectively. The content of WC in TiB₂ powder can be limited below 4.58 vol% by optimizing the milling conditions. The sintering temperature of TiB₂ powder milled can be decreased obviously, and the mechanical properties are evidently improved and the microstructure becomes more homogeneous when the powder of TiB₂ becomes finer. The relative density, hardness, bending strength, and fracture toughness of the TiB₂ ceramic fabricated at 1 700 °C reach the optimal values, which are 98.13%, 19.14 GPa, 756 MPa, and 5.71 MPa·m^1/2, respectively. The decrease of TiB₂ particle size and the introduction of WC are the potential reasons for the improvement of TiB₂ ceramic performance.

In order to reduce the emission of SO _x in the environment, sulfur compounds must be removed efficiently from fuels. Three-dimensional highly ordered meso-macroporous HPW/TiO₂ (3DO m/M HPW/TiO₂) materials were synthesized successfully by sol-gel method and applied as oxidative desulfurization catalyst for the model fuel. The characterization results displayed the existence of highly ordered meso-macroporous structures and the Keggin type of HPW was highly dispersed in TiO₂ framework. The effect of catalyst on desulfurization under different reaction conditions was studied systematically. The results showed that the catalyst exhibited excellent desulfurization performance in the hydrogen peroxide oxidation system, which could be explained by the unique meso-macroporous structure of catalyst. In addition, the catalyst showed good cycling performance and the removal rate of DBT still reached 96.1% even after 6 cycles, providing a feasible method for the development and application of fuel deep desulfurization catalysts.

The porous structure and honeycombed structure of granulated blast furnace slag formed by alkali activation (AGBFS) can be used as a promising photocatalysts substrate for the photocatalytic removal of atmospheric or water pollutants. In this study, photocatalytic activated slag granules were synthesized by loading TiO₂ on AGBFS with immersion method. The physicochemical properties and NO _x removal performance of activated slag granules/TiO₂ photocatalysts were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and photocatalytic performance test. The effects of slag particle sizes and nano-TiO₂ loading concentrations on photocatalytic efficiencies of NO _x removal were also investigated. It was found that the De-NO _x performance of activated slag granules/TiO₂ photocatalyst increased with the increasing of slag particle size in low TiO₂ loading concentration situation, while increasing the TiO₂ loading concentration would result in the opposite De-NO _x performance as slag size increased. Nevertheless, for the same size activated slag, the photocatalytic efficiency of activated slag granules/TiO₂ photocatalyst gradually improved with the increase of loading concentration of TiO₂.

The effects of magnetization on the phase composition, microstructure and thermoelectric transport properties of CoSb₃ were studied systematically. The magnetic properties of CoSb₃ material were also measured at room temperature in order to confirm its magnetic category. The results of XRD and FESEM analysis indicated that the phase composition and microstructure of the CoSb₃ were not affected by magnetization. The results of thermoelectric transport measurement showed that the electrical and thermal transport properties of materials were also not affected by magnetization. These results were mainly attributed to the diamagnetism of the CoSb₃ material, which were consistent with the results of the magnetic properties measurement. This study is expected to provide a special research perspective for studying the effects of the external conditions on the structure and properties of thermoelectric materials.

A recombinant protein ChiSifiCa, which was originally designed for regulation of calcium carbonate, was utilized to direct the mineralization of PbI₂. By the regulation of ChiSifiCa protein, PbI₂ nanoparticles composed of crystalline nanoflakes and amorphous nanorods were fabricated under environmental benign conditions. Synthetic PbI₂ was successfully applied for preparation of perovskite precursors to fabricate solar cells. This regulation of ChiSifiCa on PbI₂ improves the power conversion efficiency of corresponding perovskite solar cells to 16%. The present study may open a new avenue in the design and synthesis of materials with novel structures and functions.

The possibility of preparing cementitious materials by the alkali-activated method using Yellow River sediment (The second largest river in China) as raw material and the modification effect on different slag addition were investigated. Sodium silicate and calcium hydroxide were used as the activator, and the specimens were prepared by the press molding method. The hydration process, hydration products, pore characteristics, and mechanical properties were investigated using SEM/EDS, FTIR, TG/DTG, XRD, MIP, and uniaxial compressive strength experiments, respectively. The results showed that the compressive strength of the modified yellow river silt-based cementitious material was significantly increased when the water glass dosage was 12 wt% (Ms=1.8)) and the slag dosage was 40%, and its 90-day maximum compressive strength could reach 53 MPa.

The impact toughness and compressive strength of concrete added with calcium carbonate whisker are studied. It is found that calcium carbonate whisker can significantly improve the impact energy consumption at failure of 55 °C steam cured concrete, but has limited impact on 90 °C steam cured concrete. At the same time, SEM, XRD and LF-NMR were used to study the micro morphology, hydration product components and pore structure of the concrete, and the mechanism of the influence of calcium carbonate whisker on the impact toughness and compressive strength of concrete was analyzed.

The effect of rheological-active additives on the properties of cement suspensions and self-compacting concrete mixtures have been studied. In order to increase the rheological matrix and provide high fluidity, stone powders were used during the crushing of local mountain rocks in self-compacting concrete. Taking into account the high dispersion of rheological-active additives, highly effective plasticizers were used to regulate the reotechnological properties of cement-based mixtures. The effect of sulfonaphthalen-formaldehyde oligomer and polycarboxylate-based hyperplasticizer on rheological properties of cement systems as plasticized additive on methodology proposed by V Kalashnikov was evaluated. The flow rate of cement suspension is determined by means of mini-viscosimeter, spreading of cement-sand mortar by means of Hegermann cone, and the slump of concrete mixture by means of Abraham’s cone. On the basis of obtained results, it was determined that limestone powder was more efficient than other stone powders. Thus, when adding 40% limestone powder to the mixture, the compressive strength of the samples taken from self-compacting concrete mixture increases by 15%–30% compared to the control samples. The optimal quantities of rheological-active additives and plasticizers have been identified and the possibility of obtaining high-strength self-compacting concrete based on them has been confirmed.

A novel crystal nucleus-based cement-hardening accelerator was evaluated using various mortar and segment concrete experiments. The mechanism of hardening acceleration was investigated via hydration temperature variation analysis, hydration degree analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). In the presence of accelerator, the fluidity loss of mortar was increased after 30 minuites, and a coagulation was also observed. Moreover, based on the image of SEM, the formation of C-S-H gels was enhanced in the early hydration. As a result, the hardening accelerator could significantly boost the early strength of concrete, especially within one day of pouring, and shorten steam curing time to meet the demolding strength.

Carbide slag was used as an activator to improve the activity of anhydrous phosphogypsum. Carbide slag could greatly improve the mechanical strength of anhydrous phosphogypsum than K₂SO₄. The compressive strength of 11 wt% carbide slag and 1 wt% K₂SO₄ activated anhydrous phosphogypsum increased greatly to 8.6 MPa at 3 d, and 11.9 MPa at 7 d, and 16.0 MPa at 28 d, respectively. The rate of hydration heat was accelerated and the total hydration heat was increased, and more calcium sulfate dihydrate was formed and cross-linked with other parts which improved the compressive strength of anhydrous phosphogypsum under the effects of different activators. It was indicated that carbide slag was a highly effective and cost-efficient activator. The result provides a highly effective and low-cost method which results in a novel and high value-added method for the utilization of phosphogypsum in the future.

The stress corrosion cracking (SCC) behaviors of 2A12 aluminum alloy after annealing treatment were studied by slow strain rate testing (SSRT), electrochemical polarization measurement, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). Various concentrations of NaCl, H₂SO₄ and HCl aqueous solution were prepared to act as the corrosive solution. The experimental results show that regarding the SCC, 2A12 alloy performs best in NaCl solution but worst in HCl solution and intermediately between the above mentioned two cases in H₂SO₄ solution. For the SSRT carried out in room temperature, there is a higher decrease in elongation without large strength loss for the alloy immersed in NaCl solution. With the test conducted in H₂SO₄ solution, there is a higher strength loss and a relatively less loss of elongation compared to the one immersed in NaCl solution. With the test conducted in HCl solution, there is a relativel level loss of strength and elongation compared to either result carried out in NaCl solution or H₂SO₄ solution.

The hot tensile deformation properties and microstructure evolution of high purity C71500 cupronickel alloy at 1 023–1 273 K and 0.000 1–0.1 s⁻¹ strain rates were studied by uniaxial hot tensile deformation method. Based on the experimental data, the flow behavior, microstructure and fracture characteristics of the alloy were analyzed after considering the influence of different deformation parameters. The relationship between microstructure and high temperature (T⩾1 023 K) plasticity is discussed, and the fracture mechanism is revealed. The relationship between strain rate sensitivity coefficient and stress index and plastic deformation is discussed. The constitutive equation of the alloy is established by Johnson-Cook model. Based on the dynamic material model, the energy dissipation model is established, and Prasad’s instability criterion based on Ziegler’s expected rheological theory is used to predict the unstable region in the processing map. Processing map in hot tensile is analyzed to provide theoretical basis for different processing technology.

Split Hopkinson pressure bar (SHPB) was utilized to explore the effects of loading strain rate on the dynamic compressing strength of the titanium alloy lattice material. Results reveal that the yield strength of alloy lattice material reaches 342 MPa initially and then drops to 200 MPa before it rebounds to 252 MPa while the loading strain rate correspondingly increases from the static value 1 401/s to 2 084/s. Numerical simulations were then carried out to explore the possible reason underlying. Results show that the lattice structure changed the stress distribution and caused significate stress concentration at finite strain with high strain rate. It is believed that the strain rate strengthening effect and layer-wise failure mode are the main reasons of the above mechanical properties change.

Plasma electrolytic oxidation (PEO) coatings were formed on 7075 aluminum alloy in silicateborate based electrolyte with different duty cycles. The physical and chemical properties of the PEO coatings were thoroughly investigated. The wearing and corrosion properties of the coatings were evaluated by wearing experiments and potentiodynamic polarization tests, respectively. The results showed that the micro-hardness of the coatings first increased and then decreased with the increasing duty cycle. As a results, the wearing resistance of the coatings first increased and then decreased with the increasing duty cycle. Composition analysis proved that the coatings were mainly composed of α-Al₂O₃ and γ-Al₂O₃. The presence of wear scars on the worn surface morphology demonstrates that the three-body rolling was the main wear mechanism for coated specimen. The corrosion study showed that the coating formed in the mixed electrolyte with duty cycle of 80% showed the most superior corrosion resistance.

Phlogopite-based geopolymer was first prepared successfully under the activation of lye by compression molding at 50 MPa for 1 minute. The geopolymer was endowed with nonpolar surface via brushing modified liquid at room temperature. Swill-cooked dirty oil, whose main component was fatty acid, was used as nonpolar modifier. The raw materials and geopolymer samples were characterized by XRD, FT-IR and SEM. The compression strength of 7-day specimen run up to 36.8 MPa and its surface static water contact angle could reach 132°. The solubility of phlogopite powder directly affected the compressive strength of geopolymers and the evaluation index of mechanical strength of geopolymer based on the solubility of phlogopite powder was proposed.

The strength and microstructural analysis of recycled geopolymer are presented in this paper. Five kinds of geopolymers containing 0%, 20%, 50%, 80% and 100 % of recycled geopolymer powder were prepared using metakaolin as the source material. The alkali activator solution was a mixture of sodium silicate (Na₂SiO₃) and 12 M sodium hydroxide (NaOH). The change laws of compressive and flexural strength of recycled geopolymer specimens were investigated. And the microscopic characteristics were carried out by SEM, XRD and FTIR to observe the internal morphology and analyze changes in components of recycled geopolymers at different substitution rates. The results show that, with the increase of substitution rate of recycled geopolymer powder, the mechanical properties of recycled geopolymers degenerate and the looser structure are formed. When the substitution rate is less than 50%, the recycled geopolymer specimen meets the use requirements of heavy traffic load class. And the specimen with 80% of substitution rate satisfies the requirements of plastering mortar.

A low adsorption clay-resistant polycarboxylate superplasticizer (KN-PC) was synthesized using acrylic acid and isopentenol polyoxyethylene ether as the main reaction materials. The structural characterization and clay-resistant mechanism of the KN-PC were explored using Fourier transform infrared spectroscopy and X-ray diffraction, and the effect of the KN-PC on the performance of composite paste with various montmorillonite (MMT) contents was analyzed. Compared with ordinary polycarboxylate superplasticizer (PC), the KN-PC has a low sensitivity to the MMT. By the action of the MMT, the adsorption dosage of the KN-PC on the MMT is much smaller than that of the PC.

The 60Fc and 70Fc SF/SA blend scaffolds were prepared to mimic the functions of the native ECM for skin regeneration. Human Umbilical Vein Endothelial Cells (HUVECs) were used to examine the cell cytotoxicity, adhesion, growth factors secretion and the gene expression of associated angiogenic factors. Cell proliferation, adhesion and live-dead analyses showed that HUVECs could better attach, grow, and proliferate on the 70Fc scaffolds compared with 60Fc scaffolds and unmodified controls. Furthermore, the 70Fc scaffolds showed higher levels of specific angiogenic proteins and genes expression as well. This study suggests that the involvement of higher composition of SF (about 70%) than that of SA on the blended scaffolds could be advantageous as it is more suitable to promote angiogenesis, which is potential for vascularization during skin repair.