A systematic investigation of the graphene oxide composite reduced by either p-phenylenediamine oligomers or hydrazine hydrate was performed with field emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, fourier transform infrared, and X-ray photoelectron spectroscopy analyses. The electrical capacitance of the composite was evaluated by a cyclic voltammetry technique, while the properties of these prototype supercapacitors were measured by a chronopotentiometry technique. It was found that, under the solvothermal condition, the graphene oxide reduced by p-phenylenediamine oligomers was observed to have higher electrical capacitance than that reduced by hydrazine. The improved electrical capacitance can be attributed to that p-phenylenediamine oligomers are the more effective spacers for graphene layers; and they could also provide some pseudo-capacitance to the graphene oxide composite based on their conjugate structure. The results imply that graphene oxide modified by diamine oligomers has a good potential in energy storage devices.

In order to overcome the problem that the low conductivity and high content of graphitic N will lead to serious irreversible capacity loss, magnesiothermic denitriding method was employed to fabricate nitrogen deficient g-C₃N₄ (ND-g-C₃N₄). By controlling the reaction conditions, ND-g-C₃N₄-675 with optimal electrochemical properties was obtained. The ND-g-C₃N₄-675 has thinner two-dimensional porous structure, with high specific surface area and good conductivity. The ND-g-C₃N₄-675 showed superior cyclic stability and rate capability (After 500 cycles under 1 000 mA·g⁻¹, 2 264.9 mAh·g⁻¹ was obtained). Moreover, it presented high initial coulombic efficiency (42.2%).

A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO₂ electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs). The tin and sulfur powder were directly dissolved in a (NH₄)₂S water solution to form Sn-S precursor. After depositon and annealing, the SnO₂ film was formed, presenting as a low cost and enviromental friendly method for preparation of ESL. The films showed excellent transmittance at visible wavelength range. Moreover, the method exhibited high compatibility for doping using Cu, Cd, Li, and Zn elements. Zn doping (0.05 M) in the as-prepared SnO₂ ESL significantly improved perovskite solar cells (PSCs) performance. The highest PCE of 13.17% was achived with 15% enhancement compared to that of undoped SnO₂ ESL samples. TiCl₄ modifications on SnO₂ film improved photovoltaic performance to 14.45%, but resulted in the poor long-term stability, around 80% more degredation than that of PSCs based on Zn-doped SnO₂ films.

Nitrogen and sulfur co-doped porous nanocarbon (ZIF-C-N-S) catalyst was successfully synthesized derived from ZIF-8 and thiourea precursors. The electrochemical measurements indicate that the as-obtained ZIF-C-N-S catalyst exhibits higher electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline electrolyte and superior durability-longer than commercial Pt/C catalyst. The enhancment of electrocatalytic activity mainly be come from the open pore structure, large specific surface area as well as the synergistic effect resulted from the co-doping of N and S atoms. In addition, the ZIF-C-N-S catalyst is also used as the air cathode catalyst in the microbial fuel cell (MFC) device. The maximum power density and stable output voltage of ZIF-C-N-S based MFC are 1315 mW/m² and 0.48 V, respectively, which is better than that of Pt/C based MFC.

Herein, two nanoparticles with different dimensions, spherical carbon dots (C-dots) and sheetlike hectorite clay, were used as physical crosslinkers to fabricate C-dots-clay-poly(N-isopropylacrylamide) nanocomposite hydrogels (coded as C-dots-clay-PNIPAm hydrogels). The mechanical properties, fluorescence features and thermal-responsive properties of the C-dots-clay-PNIPAm hydrogels were evaluated. The experimental results indicate that synergistic effects of C-dots and hectorite clay nanoparticles are able to significantly enhance mechanical properties of the hydrogels. The hydrogels can be stretched up to 1730% with strength as high as 250 kPa when the C-dots concentration is 0.1wt% and the clay concentration is 6wt%. The hydrogels exhibit complete self-healing through autonomic reconstruction of crosslinked network a damaged interface. The hydrogels show favorable thermal-responsive properties with the volume phase transition around 34 °C. In addition, the hydrogels are endowed with fluorescence features that are associated with C-dots in the hydrogels. It can be expected that the as-fabricated C-dots-clay-PNIPAm hydrogels are promising for applications in sensors, biomedical carriers and tissue engineering.

SiC/7075 aluminum matrix composites were prepared by a liquid stirring method. The role of Ti facilitating the preparation of SiC/7075 aluminum matrix were studied by means of direct-reading spectrometer, scanning electron microscope, energy dispersive spectrometer, X-ray diffraction and the sessile drop method. The results show that the SiC content in the SiC/7075 composite increases with an increase of Ti addition. The addition of Ti can significantly improve the wettability of SiC/Al system, there is a critical value of above 0.5% of Ti content in improving the wettability of the Al/SiC system at 1 173 K. The temperature of the “non wetting-wetting” transition for the (Al-2Ti)/SiC system is about 1 123 K, the contact angle decreases to 88 ° at 200 seconds and reaches a stable contact angle of 28 ° at 2 100 seconds.

Fe-based coatings reinforced by spherical tungsten carbide were deposited on 304 stainless steel using plasma transferred arc (PTA) technology. The composition and phase microstructure of the coatings were evaluated using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The corrosion behaviors of the coatings in 0.5 mol/L HCl solution were studied using polarization curve and electrochemical impedance spectroscopy (EIS) measurements. The experimental results shows that the tungsten carbide improves the corrosion resistance of the Fe-based alloy coating, but increase in the mass fraction of tungsten carbide leads to increasing amount of defects of holes and cracks, which results in an adverse effect on the corrosion resistance. The defects are mainly present on the tungsten carbide but also extend to the Fe-based matrix. The tungsten carbide, acting as a cathode, and binding material of Fe-based alloy, acting as an anode, create a galvanic corrosion cell. The binding material is preferentially corroded and causes the degradation of the coating.

Chitosan (CS), hydrated zinc acetate, and rectorite (REC) were used as raw materials to prepare CS-embedded zinc oxide (ZnO) nanoparticle by a chemical precipitation process. Hydrogen-bonded REC-loaded ZnO-CS nanoparticle was to form ZnO-CS/REC nanocomposite photocatalyst, its morphology and structure were analyzed by means of FTIR, XRD, TGA, SEM, and TEM. The effects of the catalyst dosage, methyl orange (MO) initial concentration and solution pH on photocatalytic performance were also discussed. The experimental results show that the ZnO-CS/REC nanocomposite has a particle size of 100 nm with good dispersion and uniformity. Under irradiation of visible light, 0.6 g/L photocatalyst was used to degrade MO in solution for 90 min at pH 6, then the MO solution (10 mg/L) was decolored by more than 99%, indicating that the ZnO-CS/REC nanocomposite exhibited highly photocatalytic degradation activity. Therefore, the photodegradation kinetic mechanism of MO in aqueous solution is presumed.

The elemental chemical state of NiFe₂O₄@TiO₂ was changed by the reduction in order to investigate its effects on the photocatalytic performance. The synthesized NiFe₂O₄@TiO₂ samples were characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), magnetic and photocatalytic measurements. Unexpectedly, the reduction reaction does not produce oxygen vacancies O _v and TiO _x in the TiO₂ lattice. The optimal catalyst was obtained at the reducing temperature of 800 °C, and its degradation efficiency D _e to the methylene blue and reaction rate constant K _app are the highest, reaching 99.9% and 3×10⁻² min⁻¹, respectively. The reason could not be explained by both the visible light absorption and the appropriate amount of O _v and TiO _x. Instead, the lowest ratios of TiOH and Ti-O-Fe(Ni) may be responsible for the optimum photocatalytic performance.

A novel type of microencapsulated phase change materials (microPCMs) based on 1-tetradecanol (TD) core and silver-coated poly (melamine-urea-formaldehyde) (MUF) shell was successfully synthesized by in situ polymerization method followed by silver reduction. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM/EDS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to characterize the chemical structure, morphology and thermal properties of the as-prepared silver-coated microPCMs. FTIR analysis confirmed the successful encapsulation of TD with MUF wall materials. The SEM and EDS results indicated that the prepared silver-coated MUF microPCMs exhibited uniform spherical shape with a perfect silver outer layer. From XRD analysis, the Ag metal dispersed on the surface of microcapsules presented the form of elementary substance. The deposition weight of silver particles on the microcapsule surface increased with increasing the amount of silver nitrate, as indicated by EDS tests. The DSC results indicated that the melting temperature and the melting latent heat of microPCMs modified with 0.7 g of silver nitrate in 150 mL aqueous solution were 39.2 °C and 126.6 J·g⁻¹, respectively. Supercooling of the microPCMs coated with silver particles was effectively suppressed, compared with that of microPCMs without Ag. Thus, the encapsulation of TD with silver-coated MUF shell developed by this work can be an effective method to prepare the microPCMs with enhanced thermal transfer performance and phase change properties.

As one of the most active rare earths, CeO₂ has caused extensive concern due to its multifunctional properties. CeO₂-based compound oxide of M₂O₃-CeO₂ (M=La, Fe, and Al) were prepared by coprecipitation and impregnation methods. The photocatalytic performance of the samples for the degradation methylene blue was studied under UV and visible light irradiation. The effects of constituents on the properties of the CeO₂-based catalysts were investigated by XRD, TEM, BET, and UV-Vis spectrophotometer. The highest degradation of methylene blue under 230W UV light was almost 100% at 50 min by La₂O₃/Fe₂O₃-CeO₂/γ-Al₂O₃ catalyst and 99.42% at 50 min by Fe₂O₃-CeO₂/γ-Al₂O₃ catalyst. The methylene blue removal efficiency under indoor natural light reaches 93.81% by La₂O₃/Fe₂O₃-CeO₂/γ-Al₂O₃ catalyst and 92.34% by Fe₂O₃-CeO₂/γ-Al₂O₃ catalyst at 50 min. The order of catalytic degradation activity is La₂O₃/Fe₂O₃-CeO₂/γ-Al₂O₃>Fe₂O₃-CeO₂/γ-Al₂O₃> La₂O₃-CeO₂/γ-Al₂O₃>Al₂O₃, owing to their structural features. The doping of La³⁺ or Fe³⁺ onto CeO₂/γ-Al₂O produced much more oxygen vacancies under light irradiation and reduced the energy laps of CeO₂ with value of 2.86 ev, which improved the photocatalytic redox performance of the composite oxide.

n-VO₂/p-GaN based oxide-nitride heterojunctions were realized by growing high quality VO2 films with precisely controlled thickness on p-GaN/sapphire substrates by oxide molecular beam epitaxy (O-MBE). The high crystalline quality of the n-VO₂/p-GaN heterojunctions were confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis. The phase transition characteristics of the as-grown n-VO₂/p-GaN heterojunctions were systematically investigated by temperature-dependent resistivity and infrared transmittance measurements. The results indicated that an excellent reversible metal-to-insulator (MIT) transition is observed with an abrupt change in both resistivity and infrared transmittance (IR) at 330 K, which was lower than the 341 K for bulk single crystal VO₂. Remarkably, the resistivity-temperature curve was well consistent with that obtained from the temperature dependent IR transmittance. Meanwhile, the current-voltage characteristics originated from the n-VO₂/p-GaN interface were demonstrated both before and after MIT of VO₂ overlayer, which were attributed to the p-n junction behavior and Schottky contact character, respectively. The design and modulation of the n-VO₂/p-GaN based heterostructure devices will benefit significantly from these achievements.

The rare earth ion Yb³⁺ doped Bi₂WO₆ photocatalysts were synthesized by hydrothermal method. Moreover, XRD, XPS, FESEM, TEM, Ramam, N₂ adsorption-desorption isotherm measurements and UV-vis diffusion reflectance spectra were used to characterize the Yb³⁺ doped Bi₂WO₆ photocatalysts. The morphology, specific surface area, and pore volume distribution were greatly affected after Yb³⁺ ions doping. Photocatalytic performance of Bi₂WO₆ was effectively enhanced after Yb³⁺ ions doping, 6% Yb³⁺ doped Bi₂WO₆ had the best photocatalytic performance, and 96.2% Rhodamine B was degradated after irradiated 30 min, which was 1.29 times that of the pristine one. The enhanced photocatalytic performance was due to the increased specific surface area, decreased energy band gap and inhibition of photoelectron-hole recombination after Yb³⁺ ions doping.

A high-pressure hot-pressing process was applied to densify a commercial boron carbide-titanium diboride (B₄C-TiB₂) powder mixture. Nearly fully dense (98.6%) materials were obtained at 1 700 °C under a pressure of 100 MPa. Compared to the sintering temperature required to achieve similar results when a pressure of only 30 MPa was applied, the sintering temperature was found to decrease by about 200 °C under pressure of 100 MPa. Analysis of the thermodynamics and microstructure showed that the plastic deformation of the B₄C grains induced by high pressure dominated the densification mechanism when high pressure was applied. Furthermore, higher pressure resulted in remarkably improved mechanical properties of the composites, which could be traced back to the generation of stacking faults in the B₄C grains and aggregation of TiB₂.

The solid solution of (Cr_2−xMn _x)GaC with magnetic properties was synthesized by pressureless sintering. The composition, morphology, and magnetic properties of products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The experimental results indicate that the solid solubility of Mn is related to the value of x, which reaches the maximum at x=0.4 and the characteristic peaks shift effect is most obvious. After the solution treatments, the samples of (Cr_2−xMn _x)GaC still presents the layered structure of MAX phase, and the lattice parameter has decreased slightly. By characterizing the magnetic properties of (Cr_2−xMn _x)GaC, the successful doping of Mn atoms was confirmed, and the intensity of magnetism was positively correlated with the doping amounts of Mn.

The 40Bi₂O₃-30B₂O₃-(30−x)ZnO-xSrO (x=0–15mol%, BBZSr) glass system was prepared by the conventional melt quenching method. The effect of SrO addition on structure, thermal properties, chemical stability and sealing performance of BBZSr glass were investigated thoroughly. The experimental results show that the total proportions of [BO₃] group and [BO₄] group decrease and the vibrations of [BiO₃] group and [BiO₆] group become weaker with the increase of SrO addition content, suggesting the glass network structure is strengthened owing to the SrO addition. Hence, both the thermal and chemical stability were significantly improved as the SrO content was increased. When the SrO content increased from 0 to 15mol%, the glass transition temperature and softening temperature slightly increased from 380 to 388 °C and from 392.7 to 402.2 °C, respectively, meanwhile the coefficient of thermal expansion also increased from 10.49×10⁻⁶ to 11.16× 10⁻⁶/°C (30–300 °C). The BBZSr glass with 15mol% SrO exhibited excellent comprehensive properties with low glass transition temperature(384.9 °C), low softening temperature(400.3 °C), high coefficient of thermal expansion (11.14×10⁻⁶ C, 30–300 °C), good thermal and chemical stability. Besides, the glass had the good wetting behavior and sealing performance for Al-50%Si alloy.

The structure and chemical durability of non-alkali aluminoborosilicate glasses with various contents of ZnO were investigated. As the replacement of MgO by ZnO increases from 0 to 3.2mol%, the average number of bridge oxygen per tetrahedron (BO/T) as a measure of network connectivity increases from 2.84 to 3.04, and the chemical durability improved. The weight loss ratio (WLR) of glass etched in 10vol% HF (20 °C, 20 min) solution decreased from 4.809 to 4.509, and in 5wt% NaOH (95 °C, 6 h) solution decreased from 1.201 to 0.994. The replacement of MgO by ZnO further increased to 6.4mol%, the value of BO/T decreased to 3.04 instead, and thus the chemical durability deteriorated. The WLR of HF-acid and NaOH-alkali corrosion increased to 6.683 and 1.994, respectively. The chemical durability shows strongly dependent on the network connectivity and exhibits mixed intermediate effects during the replacement of MgO by ZnO.

The products of monoammonium phosphate containing Cr³⁺ resulted in disqualification, and further posed a serious threat to ecological environment and human beings. Herein, the porous adsorbent of fluor(calcium silicate) composites (FCSc) was prepared by hydrothermal method using diatomaceous earth, hydrated lime and additive (NaF) as raw materials, which was characterized and used for the removal of Cr³⁺ from monoammonium phosphate solutions. The effects of different parameters, such as solution pH, initial Cr³⁺ concentration, temperature and contact time on the adsorption of Cr³⁺ onto FCSc were investigated in details. The results indicated that the adsorption process was in agreement with the pseudo-second-order kinetic model and Freundlich isotherm. The spontaneous and endothermic nature of the adsorption process was obtained by analyzing various thermodynamic parameters (ΔG ⁰, ΔH ⁰, and ΔS ⁰). In addition, computational monte carlo simulations between Cr³⁺ ions and FCSc were conducted to elucidate the adsorption mechanism. Such kind of porous adsorbent provided a potential application in the removal of impurities from monoammonium phosphate industry.

Ultrafine grain tungsten heavy alloys (WHAs) were successfully produced from the nanocrystalline powders using spark plasma sintering. The present study mainly discussed the effects of sintering temperature on the density, microstructure and mechanical properties of the alloys. The relative density of 98.12% was obtained at 1 050 °C, and the tungsten grain size is about 871 nm. At 1 000 °C-1 200 °C, the mechanical properties of the alloys tend to first rise and then goes down. After SPS, the alloy exhibits improved hardness (84.3 HRA at 1 050 °C) and bending strength (987.16 MPa at 1 100 °C), due to the ultrafine-grained microstructure. The fracture mode after bending tests is mainly characterized as intergranular or intragranular fracture of W grains, interfacial debonding of W grains-binding phase and ductile tearing of binding phase. The EDS analysis reveals a certain proportion of solid solution between W and Ni-Fe binding phase. The good mechanical properties of the alloys can be attributed to grain refinement and solid solution strengthening.

The experimental study of Bauschinger effect in Mn18Cr18N austenitic stainless steel was presented by compression-tensile cyclic loading tests with the prestrains ranging from 0.005 to 0.1, which was illustrated utilizing stress-strain curves and analysed by TEM images from aspects of microstructural mechanisms. Moreover, the Bauschinger effect and its associated roundness phenomenon in reverse flow curve with respect to different cycles and cyclic strain amplitudes were evaluated in a quantitative manner. The experimental results indicate that Bauschinger effect is apparent during the test. At smaller cyclic strain amplitude, intergranular backstress is the main source of Bauschinger effect. With further increasing of cycles, dislocation density increases and dislocation movement is hindered in the reverse deformation. Therefore, Bauschinger effect is weakened to some extent. At large cyclic strain amplitude, backstress originating from the dislocation pile-up at grain boundaries and the continuous formation of deformation twins dominate the Bauschinger effect. In addition, the backstress results in the roundness of reverse curve during cyclic loading. The larger value of Δε _p ^*, the more obvious the roundness of the reverse curve, and the more significant the Bauschinger effect.

The dimpling defects caused by conventional hemispherical punch in doubly curved sheet metal reconfigurable die forming process were considered. The rotatable cubic punch (RCP) was developed to suppress the dimpling defects more effectively and conveniently. The former punch contacts with the work-piece through a point-surface contact and the latter punch contacts with the work-piece through a surface-surface contact. A series of stamping experiments were carried out using three different punches (hemispherical punch, RCP, chamfered-RCP) with three different loads. Some finite element simulations about the stamping experiments were carried out. The dimple scales were evaluated through the dimple depths. The corresponding data were obtained by 3-D scanning and FE result analysis respectively. A 3-D plate forming machine was developed, in which chamfered-RCP was adopted. Plate forming experiments were carried out on this machine. The stamped samples show a clear basis for the performance of chamfered-RCP. The study provided a means to guide the design of punches for dimpling suppression used in reconfigurable die.

To improve the weak corrosion resistance of silicon steel to acid solution and alkaline solution with high temperature, a stable hierarchical micro/nanostructure superhydrophobic surface with myriad irregular micro-scale hump and sheet-like nanostructure was successfully prepared on silicon steel by a simple, efficient and facile operation in large-area laser marking treatment. The morphology, composition, wettability of the as-prepared surface were studied. The superhydrophobic performance of the surface was investigated as well. Additionally, the corrosion resistance of the superhydrophobic surface to acidic solutions at room temperature and alkaline solutions at high temperature (80 °C) was carefully explored. The corrosion resistance mechanism was clarified. Moreover, considering the practical application of the surface in the future, the hardness of the hierarchical micro/nanostructure superhydrophobic surface was studied. The experimental results indicate that the hierarchical micro/nanostructure surface with texture spacing of 100 µm treated at laser scanning speed of 100 mms/presents superior superhydrophobicity after decreasing surface energy. The contact angle can be as high as 156.6°. Additionally, the superhydrophobic surface provide superior and stable anticorrosive protection for silicon steel in various corrosive environments. More importantly, the prepared structure of the surface shows high hardness, which ensures that the surface of the superhydrophobic surface cannot be destroyed easily. The surface is able to maintain great superhydrophobic performance when it suffers from slight impacting and abrasion.

The failure patterns and energy evolution of three types of shaft lining concrete subjected to static and dynamic loading were reported. The energy and damage characteristics of concrete were determined by means of a uniaxial hydraulic servo machine, acoustic emission (AE) equipment, a split Hopkinson pressure bar (SHPB) and an ultrasonic wave analyser. The experimental results indicate that the confluence of multiple cracks forms a penetrating cross section in normal high-strength concrete (NHSC) under the condition of static loading, while the elastic energy that surges out at failure can cause tremendous damage when subjected to dynamic loading. A single crack was split into multiple propagation directions due to the presence of fibres in steel fibre-reinforced concrete (SFRC); adding fibre to concrete should be an effective way to dissipate energy. The non-steam-cured reactive powder concrete (NSC-RPC) designed in this paper can store and dissipate more energy than normal concrete, as NSC-RPC exhibits a strong ability to resist impact. Applying NSC-RPC to the long-service material of a shaft lining structure in deep underground engineering is quite effective.

By using NaOH and Na₂SiO₃ as the activator, the mechanical properties and shrinkage of the geopolymer after incorporation of 0%, 10%, 20%, and 30% epoxy resin were investigated. The mechanism of epoxy resin toughening metakaolin based geopolymer was analyzed by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. It was shown that with the increases of epoxy resin, the shrinkage performance was obviously improved and the flexural strength increased by 53.5%. The compressive strength of EGP10, EGP20, and EGP30 increased by 49.12%, 57.04%, and 65.34% after curing for 28 days, respectively. There were five obvious vibration peaks of 811 cm⁻¹, 1 000 cm⁻¹, 1 050 cm⁻¹, 1 590 cm⁻¹, and 3 400 cm⁻¹ in the geopolymer and the undisturbed metakaolin. More geopolymer gels were formed in the material and the microstructure was more compact.

Structure and mechanical properties of Calcium silicate hydrate (C-S-H) at a molecular level act as “DNA” of cement-based construction materials. In order to understand loading resistance capability of C-S-H gel, research on molecular dynamics (MD) was carried out to simulate the uniaxial tension test on C-S-H model along x, y, and z directions. Due to the structure and dynamic differences of the layered structure, the C-S-H model demonstrates heterogeneous mechanical behavior. On an XY plane, the cohesive force can reach 4 GPa which is mainly provided by the Ca-O and Si-O ionic-covalent bonds. The good plasticity of calcium silicate sheet is attributed to the silicate branch structure formation and the recovery role of interlayer calcium atoms. However, in z direction, C-S-H layers connected by the unstable H-bonds network, have the weakest tensile strength 2.2 GPa. This results in the brittle failure mode in z direction. The relatively low tensile strength and poor plasticity in z direction provides molecular insights into the tensile weakness of cement materials at macro-level.

A citrate-assisted hydrothermal method was utilized for the preparation of Sr-substituted hydroxyapatite (HA) nanoparticles. The influences of Sr-substituting degree on the phase identifications, microstructures and colloidal stability of the resultant products were studied. The experimental results show that the crystalline structures and morphologies of final resultants are significantly changed by controlling the Sr-substituting degree. As the Sr-substituting degree increases, the colloidal stability of samples first increases and then decreases rapidly; the morphology of the product first changes from nanorods to short nanorods rod and then becomes nanowires. Uniform HA hexagonal nanorods with high aspect ratio (>4.0) and excellent aqueous colloidal stability were prepared by 6 h hydrothermal reaction at 180 °C without Sr substitution. The dispersion underwent the phase transition from isotropic to liquid-crystalline state upon the increasing concentration of 25wt% and the complete liquid-crystalline phase was achieved when at the concentration above 31wt%. These novel findings provide new insights into the role of Sr substitution on both the citrate-assisted hydroxyapatite crystallization and tailoring of colloidal stability. Moreover, HA liquid crystal behavior was successfully observed, which lays a foundation for the fabrication of macroscopically assembled hydroxyapatite-based biomimetic materials for biomedical applications.

A post-treatment of hydrothermal process was conducted to evaluate its effects on the material characteristics and mechanical properties of plasma-sprayed pure HA and HA/20% YSZ coatings. Surface morphology and microstructural changes, relative element contents as well as phase transformations were analyzed by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffractometry. Both microhardness and Young’s modulus were measured. CaCO₃ was found existing before and after the whole process of post-treatment. Peaks of impurity phases such as CaO, TCP, and TTCP of as-sprayed coatings were observed to disappear while HA peaks show a tendency of getting higher and wider over time. Surface morphology of SEM analysis presents a clear deposition behavior of ultrafine HA crystallized particles and cross-sectional analysis exhibits a dense and fine structure. Mechanical properties of HA/20%YSZ coatings are found to be significantly higher than those of pure HA coatings and both of which displayed an overall increase with the heating time, indicating enhanced performances.

In order to improve the efficiency of β-CD, the inclusion complex of β-CD and resorcinol bisdiphenylphosphate (RDP) (β-CD@RDP) was prepared, which β-CD was as the host component and RDP was as the guest. The structure and thermal stability property of β-CD@RDP was also characterized. EP/β-CD@ RDP composites were prepared by adding β-CD@RDP into EP matrix. The results of thermogravimetric test showed that the flame retardant systems could effectively increase the corresponding temperature of EP matrix to reach the maximum thermal decomposition rate, and exhibited good char-forming property. When the amount of β-CD@RDP in EP was 20wt%, the limiting oxygen index (LOI) value of EP was increased to 26.5% from 19.8%, and the vertical burning test (UL-94) reached V-1 level. The cone calorimeter test indicated that 20wt% loading in EP could reduce the peak of heat release rate (PHRR) and the total heat release (THR) of EP by 94.7% and 93.4% respectively, and the peak of smoke production rate (PSPR) and the total smoke production (TSP) was reduced by 16.7% and 22.2%, respectively. Therefore, the addition of β-CD@RDP could reduce the fire risk of EP effectively.

Polystyrene crosslinked microspheres were prepared by soap-free emulsion polymerization using styrene (St) and divinylbenzene (DVB) as monomers; then, the microporous structure was knitted by the Friedel-Crafts alkylation reaction, and the Au nanoparticles (AuNPs) were loaded into the pores through thermal reduction, to obtain AuNPs/hyper-crosslinked microporous polymer composite microspheres. SEM and particle-size test results show that the microspheres show good monodispersity. The micropore analysis indicates that the specific surface area and the pore volume of the microporous polymer microspheres decrease with increasing DVB content, and when the DVB content is 0.1%, the specific surface area reaches a maximum of 1 174.6 m²/g. After loading AuNPs, the specific surface area and the amount of micropores of the composite microspheres decrease obviously. The results of XRD and XPS analyses suggest that HAuCl₄ is reduced to AuNPs. The composite microspheres show a good catalytic performance for the reduction catalyst of 4-nitrophenol.