Hierarchical hollow spherical CdS nanostructures were synthesized via a simple microwave hydrothermal(M-H) process using CdCl₂·H₂O and Na₂S₂O₃·5H₂O as raw materials and adding ethylenediaminetetraacetic acid (EDTA) as template. The obtained products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and high-resolution transmission electron microscopy (HRTEM). Ultraviolet-visible (UV-vis) spectroscopy was used to study the optical properties of CdS. The results demonstrate that the hierarchical hollow spherical CdS with a diameter range of 400−600 nm is self-assembled by nanoparticles of 30 nm and in a wurtzite structure. EDTA and microwave play an important role on the formation of the hollow hierarchical morphology. The effect of the microwave and possible growth mechanism were discussed. UV-vis spectroscopy indicates that the CdS crystallites could be used as a potential blue light emitting material.

Zn_0.95Co_0.05O nanotubes, as well as nanowires, were controllably synthesized by electrophoretic deposition method using anodic aluminum oxide (AAO) as template, and the mechanism of electrophoretic deposition was discussed. Careful characterization indicates that the prepared nanotubes and nanowires are of poly-crystal wurtzite structure and composed with 8−15 nm nano-crystals. The doped Co²⁺ occupied the Zn²⁺ sites in the ZnO lattice. Magnetic investigation indicates that the obtained nanotubes and nanowires are of room-temperature ferromagnetic. The magnetism of the nanotubes is much higher than that of the nanowires for the surface-preferential Co distribution.

The NiO nanowires were prepared by a facile PEG assisted hydrothermal method using NiC₂O₄∙2H₂O as a precursor compound. The microstructure of the samples was characterized by SEM and XRD. The gas sensing properties of the NiO nanowires toward ethanol was also investigated. The results show that PEG plays a key role in the synthesis of wire-like NiO. The NiO nanowires show excellent sensing performances to ethanol gas. This morphology holds substantial promise for applying NiO as a potential gas sensing material for future sensor application.

The effect of applied voltage on nanopore formation stability of porous anodized alumina (PAA) in oxalic acid electrolyte was investigated. The Al anodization at a constant applied voltage is a popular electrochemical method to synthesize PAA templates. The experimental observations of Al anodization are used to compare the predictions of the THAMIDA model for interpore distance and the stability criterion of the SINGH model. It is found that, in the electrolyte of pH = 0.96, the interpore distance-applied voltage has a linear dependence coefficient of 2.24 nm/V, which agrees well with the THAMIDA model. It has also been confirmed that pore formation is instable at above 60 V which can be predicted by SINGH model. A second unstable growth regime below 30 V is also observed, which is not predicted by any of the models.

Y₂O₃-doped ZnO−Bi₂O₃ thin films were fabricated on silicon substrates by sol-gel process and annealed in air at 750 °C for 1 h. Microstructure and electrical properties of ZnO thin films were investigated. XRD analysis shows that all peaks of ZnO thin films are well matched with hexagonal wurtzite structure of ZnO. SEM results present that the ZnO grain size decreases with the increase of dopant concentration, which means that rare earth doped can refine the grain size. The thickness of each layer is uniform and the value of thickness is about 80 nm. The nonlinear V-I characteristics with the leakage current of 0.46 μA, the threshold field of 110 V/mm and the nonlinear coefficient of 3.1 could be achieved when the films contain 0.2% (mole fraction) yttrium ion.

Zirconium nitride thin films were fabricated using arc ion plating under negative substrate biases to investigate the influence of substrate bias on the ZrN films. The phase, composition, and surface morphology of the ZrN films, with respect to substrate bias, were studied by XRD, EPMA, and FE-SEM, respectively. The results show that cubic ZrN and hexagonal Zr phases form in the ZrN films. The competition between surface energy and strain energy makes the preferred orientation change from (111) to (200) and then back to highly (111) preferred orientation as a function of substrate bias. With the increase of bias voltage, the crystallite size of ZrN films reduces from 30 to 15 nm. Meanwhile, the film microstructure evolves from an apparent columnar structure to a highly dense equiaxed structure, indicating that the ion bombardment enhanced by substrate bias can suppress the columnar growth in the ZrN films. Deposition rate and mole ratio of Zr to N increase with the increase of bias voltage and reach the maximum at −50 V, and then show a decline trend when bias voltage further increases.

Nitrogen doped titanium dioxide (N-TiO₂) coatings were fabricated by oxidation of the TiN_x coatings in air. TiN_x coatings were prepared on stainless steel (SS) substrates by plasma surface alloying technique. The reference TiO₂ sample was also deposited by oxidation of the Ti coatings in air. The as-prepared coatings were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and ultra violet-visible absorption spectroscopy (UV-Vis). The formation of anatase type TiO₂ is confirmed by XRD. SEM measurement indicates a rough surface morphology with sharp, protruding modules after annealing treatment. The band gap of the N-doped sample is reduced from 3.25 eV to 3.08 eV compared with the undoped one. All the N-doped samples show red shift in photoresponse towards visible region and improved photocurrent density under visible irradiance is observed for the N-doped samples. The photocatalytic activity was evaluated via the photocatalytic oxidation of methylene blue (MB) in aqueous under visible light irradiation. The results reveal that the N-doped samples extend the light absorption spectrum toward the visible region. The degradation rate of N-TiO₂ is 20% in visible irradiation for 150 min.

Dielectric properties and varistor performance of sol−gel prepared Ni-doped calcium copper titanate ceramics (CaCu₃Ni_xTi₄O_12+x, x=0, 0.1, 0.2, 0.3) were investigated. SEM and XRD were used in the microstructural studies of the specimens and the electrical properties were investigated for varistors. XRD patterns show that the CCTO ceramics were single phase with no Cu-rich phase. SEM results indicated that the samples had smaller grain sizes than those synthesized by traditional solid-state reaction methods. The experimental results show that the highest dielectric constant and lower dielectric loss occur when x=0.2. When x=0.3, the lowest leakage current is obtained and the maximum value reaches 0.295; meanwhile, the lowest threshold voltage and nonlinear coefficient are found, the minimum values of them are 1326 V/mm and 3.1, respectively.

Lead-free piezoelectric ceramics (1−x)(K_0.5Na_0.5)NbO₃−xLiBiO₃ [(1-x)KNN−xLB] (x=0, 0.0005, 0.002, 0.004, 0.006, 0.008, 0.010) were prepared by an traditional solid-state reaction. The microstructure and electrical properties of the ceramics were investigated. The results show that all (1−x)KNN−xLB ceramics possess pure perovskite structure when x≤0.01, no trace of any secondary phase is detected, and the phase structure of the ceramics transits abnormally from orthorhombic to cubic. With the increase of the LB content, the size of grain gradually becomes small, the piezoelectric constant d₃₃ and the planar electromechanical coupling coefficient k_p first increases and then decreases. The d₃₃ and k_p of the ceramics reach their maximum values 115 pC/N at x=0.002 and 0.2701 at x=0.001, respectively. The dielectric constant ε_r of the ceramics firstly increases evidently and then decreases with the increase of x, the maximum value 871.8 is obtained at x=0.006.

Barium strontium titanate (Ba_1−xSr_xTiO₃, BST) and strontium barium niobate (Sr_xBa_1−xNb₂O₆, SBN) are important ferroelectric materials with excellent pyroelectric, dielectric properties and faster response time of infrared radiation. SBN/BST composite ceramics with different mole ratios of Nb and Ti were fabricated using a powder-sol (P-S) method with Nb₂O₅ fine powders suspended in the barium strontium titanate (BST in short) sol solution. The X-ray diffraction results indicate that three intermediate phases, i.e. TiO₂, BaNb₂O₆ and SrNb₂O₆, are developed during the formation of SBN-BST. Powders obtained from dried gels are calcined at 800 ℃ for 3 h. The Ti_2p spectra of only one spin-orbit doublet are observed, which indicates one 4+ chemical state in the composite ceramics. The binding energies of Nb element depend strongly on composition.

CdMnTe (CMT) crystals were grown from Te solution with vertical Bridgman method under accelerated crucible rotation (ACRT) technique. Ingot in diameter of 30 mm and length of 60 mm was obtained. The result shows that as-grown CMT has fewer twins compared with the one grown by conventional vertical Bridgman method. However, IR microscopy shows that the microscopic growth interface morphology is non-uniform and irregular, which is attributed to higher Te inclusions density. Meanwhile, the laser confocal microscope images reveal that the Te phases are deposited randomly in the Te-rich CMT region with irregular shapes and voids. By optimizing the growth parameters to obtain a smooth interface, the Te solution vertical Bridgman technique can effectively reduce the twins in CMT crystal.

Many defects in semi-insulating (SI) cadmium zinc telluride (Cd_1−xZn_xTe or CZT) ingots grown by the melt methods act as trapping centers to introduce deep levels in the band gap, which has strong effects on CZT detection properties. The thermally stimulated current (TSC) spectroscopy was used to measure these traps, and the initial rise method and the simultaneous multiple peaks analysis (SIMPA) method were introduced to characterize trap levels in SI-CZT:In. The results show that there is a larger error in the determination for the trap peaks with the initial rise method due to the interference of overlapping peaks, while the SIMPA method demonstrates a better performance in resolving these overlapping peaks simultaneously for a full characterization of trap levels. On this basis, a theoretical SIMPA fitting, which is composed of ten trap levels and a deep donor level E_DD dominating the dark current in SI-CZT:In, is achieved. Furthermore, the reason of high resistivity in CZT:In was explained by the relationship between E_DD level and Fermi level.

LiFePO₄ co-doped with Mg²⁺ and Co⁴⁺ ions was synthesized by a solid state reaction method. The structure and electrochemical properties of the prepared LiFe_0.99Mg_0.005Co_0.005PO₄ were investigated by X-ray diffraction (XRD), galvanostatic charge-discharge experiment and cyclic voltammograms (CV). Specific discharge capacity of LiFePO₄ co-doped with Mg and Co ions reach 147.2 mA·h/g at 0.1C and 133.3 mA·h/g at 1C. The results of CV show that the reversibility of lithium extraction/insertion in LiFePO₄ can be promoted by (Mg²⁺, Co⁴⁺) multiple-ion doping.

LiVPO₄F/C samples were synthesized by one-step solid-state reaction and two-step solid-state reaction methods, respectively. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance tests were adopted to characterize the properties of LiVPO₄F/C. XRD results show that the LiVPO₄F/C samples prepared by one-step solid-state reaction method have the same triclinic structure (space group  as that synthesized by conventional two-step solid-state reaction. SEM image exhibits that the particle size of LiVPO₄F/C prepared by one-step solid-state reaction method is smaller than that of the sample synthesized by two-step solid-state reaction. The improved electrochemical properties of the LiVPO₄F/C are attributed to the depressed grain size and enhanced electrical conductivity produced via one-step solid-state reaction method using oxalic acid as both reduction agent and carbon sources. AC impedance measurements also show that the LiVPO₄F/C synthesized by one-step solid-state reaction route significantly decreases the charge-transfer resistance.

A one-step hydrothermal procedure to form Fe₃O₄ nanospheres on chemically reduced graphene oxide (CRGO) surfaces was proposed, and these nanocomposites were used as substrates for enzyme immobilization. The as-prepared Fe₃O₄/CRGO nanocomposites were characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), FT-IR and vibrating sample magnetometer. Fe₃O₄ microspheres are randomly distributed on graphene sheets, and the average diameter of Fe₃O₄ microspheres is about 260 nm. Horseradish peroxidase (HRP) was used as a model enzyme to investigate the immobilization activity. The HRP loading was 23.3 mg/g supports and retained 70% of the first use after ten cycles. The catalyzed capability of immobilized HRP was investigated and the immobilized HRP exhibited broader pH stability and excellent reusability. The results show that the Fe₃O₄/CRGO nanocomposites are appropriate for the immobilization of enzyme, and could have potential use in practical.

Three kinds of hydroxyapatite (HA) microspheres were prepared using a flame-drying method. The morphologies and selected area diffraction of HA slurries were determined by TEM. The phase composition, and morphologies were studied by TEM, X-ray diffractometer (XRD), scanning electron microscope (microstructure, SEM), respectively. The TEM result shows that the slurries are composed of nano-particle HA. With the aging time of HA slurry prolonging, the morphology of HA particle changes from spherical ACP (amorphous calcium phosphate) to rod-like acicular nano-crystal morphology. Low temperature can also cause the crystallinity degree of HA slurry decrease obviously. The XRD result shows that the crystallinity of HA microspheres prepared from three kinds of HA slurry is consistent with its corresponding slurry. The SEM result shows that the sphericity of the microspheres prepared by pure HA slurry without ammonia water is the best among three kinds of microspheres, then the HA slurry containing ammonia solution forms the hollow microspheres with open pore, and ice-water mixture flurry.

A novel β type Ti35Nb2Ta3Zr alloy with low modulus (48 GPa) was fabricated using vacuum consumable arc melting. The corrosion resistance and cytotoxicity of Ti35Nb2Ta3Zr were evaluated. The open circuit potential, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods were used to determine the corrosion resistance. In Ringer’s solution, Ti35Nb2Ta3Zr alloy exhibits better corrosion resistance, as compared to that of Ti6Al4V and Ti. The cytotoxicity tests indicate that the biocompatibility of Ti35Nb2Ta3Zr is as good as Ti and Ti6Al4V which are widely used in biomedical fields. Based on corrosion resistance and cytotoxicity, the novel β type Ti35Nb2Ta3Zr alloy can be considered as a potential biomaterial.

The objective was to develop and evaluate the porous medical implant scaffolds designed via digital method and fabricated by laser additive manufacturing. A porous artificial femur model and several vessel scaffolds with custo, mized design were created based on the widely used computed tomography (CT) technology and Pro/Engineer software, and then were obtained by selective laser melting of powdered titanium-alloy material. The fabricating results show that supports are not required with the improvement of the processability of lattice, and porous scaffolds with good interconnectivity can be fabricated. Some issues also appear, such as the low geometric accuracy of lattices. The exploited design freedom is an expected benefit in medical field due to the individual characteristic of each patient. It is expected that more scaffolds will be developed and applied in practical fields with further study on design, process and biocompatibility.

Ti matrix syntactic foam has potential in the orthopaedic application because of its good biocompatibility, corrosion resistance and varied elastic modulus. Ti matrix syntactic foams embedded with thick-wall ceramic microspheres (CMs) were prepared using a powder metallurgy method. The structure, compressive behaviour and elastic modulus of Ti matrix syntactic foam embedded with thick-wall CMs were analyzed and compared with those embedded with thin-wall CMs. Results show that the compressive strength of Ti matrix syntactic foam increases with the increase of the volume fraction of CMs clearly. However, the strength increase would not increase the elastic moduli obviously which are still similar with those of human bone.

To further enhance shape memory effect (SME) and improve treatment technique in Fe-based shape memory alloys, an Fe17Mn5Si8Cr5Ni0.5NbC alloy was subjected to electropulsing treatment after pre-deformation. The results show that the shape recovery ratio increases with the amount of pre-deformation up to 10%. The maximum shape recovery ratio after electropulsing treatment is 8% greater than that after ageing at 1073 K. The number of NbC particles induced by electropulsing treatment is increased and the size of the particles is decreased with the amount of tensile pre-deformation up to 10%, and NbC carbides are precipitated more quickly through electropulsing treatment than by ageing.

In order to dynamically analyze a crack in a functionally graded materials layer for plane problem under dynamic loadings, a stochastic model is established for plane problem in which the material properties of the functionally graded materials layer vary randomly in the thickness direction, and the crack is parallel to the materials faces. A pair of dynamic loadings applied on the crack faces are treated as stationary stochastic processes of time. By dividing the functionally graded materials layer into several sub-layers, this problem is reduced to the analysis of laminated composites containing a crack, the material properties of each layer being random variables. A fundamental problem is constructed for the solution. Based on the use of Laplace and Fourier transforms, the boundary conditions are reduced to a set of singular integral equations, which can be solved by the Chebyshev polynomial expansions. The stress intensity factor history with its statistics is analytically derived. Numerical calculations are provided to show the effects of the related parameters. The results show that the increase of crack length, random field parameter β and crack location ratio h₂/h leads to the increase of the mathematical expectation and standard deviation of normalized stress intensity factor history.

A new type of hierarchical ZnSnO₃-SnO₂ flower-shaped nanostructure composed of thin nanoflakes as secondary units is successfully prepared through a simple hydrothermal process. The polyhedral ZnSnO₃ core acts as a sacrificed template for the growth of hierarchical SnO₂ nanoflakes, and the average thickness of SnO₂ nanoflakes is around 25 nm. The time-dependent morphology evolution of ZnSnO₃-SnO₂ samples was investigated, and a possible formation mechanism of these hierarchical structures is discussed. The gas sensor based on these novel ZnSnO₃-SnO₂ nanostructures exhibits high response and quick response- recovery traits to ethanol (C₂H₅OH). It is found that ZnSnO₃-SnO₂ nanoflakes have a response of 27.8 to 50×10^-6 C₂H₅OH at the optimal operating temperature of 270 °C, and the response and recovery time are within 1.0 and 1.8 s, respectively.

Large-scale synthesis of ZnO hexagonal pyramids was achieved by a simple thermal decomposition route of precursor at 240 ^oC in the presence of PEG400. The precursor was obtained by room-temperature solid-state grinding reaction between Zn(CH₃COO)₂·2H₂O and Na₂CO₃. Crystal structure and morphology of the products were analyzed and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The results of further experiments show that PEG400 has an important role in the formation of ZnO hexagonal pyramids. Difference between the single and double hexagonal pyramid structure may come from the special thermal decomposition reaction. The photoluminescence (PL) spectra of ZnO hexagonal pyramids exhibit strong near-band-edge emission at about 386 nm and weak green emission at about 550 nm. The Raman-active vibration at about 435 cm^-1 suggests that the ZnO hexagonal pyramids have high crystallinity.

The flower-like ZnO microstructure was prepared by a straightforward microwave-hydrothermal technique using zinc chloride and arginine solution as reactants. The as-synthesized crystal structure and morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the optical properties of the ZnO nanostructure were studied by Raman and photoluminescence (PL) spectra, which confirms the high crystal quality of ZnO microstructure. The as-synthesized ZnO flowers exhibit a significant enhancement of photocatalytic capability toward degrading methyl blue (MB) under UV light,  the photodegradation of MB reaches 95.60%, only within 2 h of adding the as-synthesized ZnO  in the MB solution under UV irradiation. Furthermore, the photodegradation could be described as the pseudo-first-order kinetics with degradation rate constant of 1.0675-1.6275 h^-1, which is relative to the morphology of the structures.

Red-emission (Y_0.95Eu_0.05)₂O₃ submicron spheres and microplates were selectively obtained via hydrothermal precursor synthesis (150 °C, 12 h) followed by calcination at 1000 °C. Characterizations of the products were carried out by combined means of XRD, FT-IR, FE-SEM and PL analysis. The precursors could be modulated from basic-carbonate submicron spheres to normal carbonate microplates by increasing the molar ratio of urea to Y+Eu from 10 to 40-100. The resultant oxides largely retain their respective precursor morphologies at 1000 °C, but morphology confined crystal growth was observed for the microplates, yielding more enhanced exposure of the (400) facets. Both the (Y_0.95Eu_0.05)₂O₃ spheres and microplates exhibit nearly identical positions of the PL bands and similar asymmetry factors of luminescence [I(⁵D₀→⁷F₂)/I(⁵D₀→⁷F₁), ~11] under 250 nm excitation, but the microplates show a significantly strong red emission at ~613 nm (~1.33 times that of the spheres) owing to their larger particle size and denser packing of primary phosphor crystallites.

In order to develop the high photocatalytic activity of TiO₂ under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated carbon (SAC) supported photocatalyst doped with upconversion luminescence agent Er³⁺:YAlO₃ was prepared by immobilizing Er³⁺:YAlO₃/TiO₂, which was obtained by combination of Er³⁺:YAlO₃ and TiO₂ using sol-gel method, on the surface of SAC. The crystal phase composition, surface structure and element distribution, and light absorption of the new photocatalysts were examined by X-ray diffraction (XRD), energy dispersive X-ray spectra (EDS) analysis, scanning electron microscopy (SEM) and fluorescence spectra analysis (FSA). The photocatalytic oxidation activity of the photocatalysts was also evaluated by the photodegradation of methyl orange (MO) in aqueous solution under visible light irradiation from a LED lamp (λ>400 nm). The results showed that Er³⁺:YAlO₃ could perform as the upconversion luminescence agent which converts the visible light up to ultraviolet light. The Er³⁺:YAlO₃/TiO₂ calcinated at 700 °C revealed the highest photocatalytic activity. The apparent reaction rate constant could reach 0.0197 min^-1 under visible light irradiation.

A nano-MoS₂/bentonite composite was synthesized by calcinating MoS₃ deposited on bentonite in H₂. The obtained composite was characterized using thermogravimetric analysis, X-ray diffractometer, scanning electron microscope and transmission electron microscope. The results show that nano-MoS₂ particles are distributed on the surface of bentonite and form layered structures with layer distance of about 0.64 nm. The composite presents an excellent performance for the removal of methyl orange. Some operation conditions affect the removal efficiency of methyl orange, such as dosage of composite, initial concentration of methyl orange, temperature and pH value. However, light source does not influence the removal efficiency. The removal mechanism is attributed to the adsorption of methyl orange on the nano-MoS₂/bentonite composite. The adsorption of methyl orange on the composite is in accordance with the pseudo-second-order kinetic model.

Al₂O₃/Au nano-laminated composite coatings were prepared by means of magnetron sputtering. The coating was compact and comprised of nano-laminated Al₂O₃ and Au layers. High temperature cyclic oxidation test was employed to investigate the oxidation resistance of the composite coatings. The results revealed that the applied Al₂O₃/Au nano-laminated composite coatings improved the oxidation and spallation resistance of the stainless steel substrate significantly. The mechanism accounting for oxidation resistance was related with the suppression of inward oxygen diffusion and selective oxidation of Cr in the substrate. The mechanism accounting for spallation resistance was attributed to the relaxation of thermal stress by the nano-laminated structure.

Al₂O₃-13%TiO₂ (mass fraction) coatings, prepared by laser cladding on nickel-based alloy, were heated using high frequency induction sources. The coating microstructure and the interface between bond coating and ceramic coating were characterized by SEM, XRD and EDS. The results show that two-layer substructure exists in the ceramic coating: one layer evolving from fully melted region where the sintered grains grow fully; another layer resembling the liquid-phase-sintered structure consisting of three-dimensional net where the melted Al₂O₃ particles are embedded in the TiO₂-rich matrix. The mechanism of the two-layer substructure formation is also explained in terms of the melting and flattening behavior of the powders during laser cladding processing. The spinel compounds NiAl₂O₄ and acicular compounds Cr₂O₃ are discovered in the interface between bond coating and ceramic coating. It proves that the chemical reactions in the laser cladding process will significantly enhance the coating adhesion.

Monolayer ultra-large graphene oxide (UL-GO) sheets with diameter up to about 100 μm were synthesized based on a chemical method. Transparent conductive films were produced using the UL-GO sheets that were deposited layer-by-layer on a substrate by the Langmuir-Blodgett (L-B) assembly technique. The films produced from UL-GO sheets with a close-packed flat structure exhibit exceptionally high electrical conductivity and transparency after thermal reduction. A remarkable sheet resistance of 605 Ω/sq at 86% transparency is obtained, which outperforms the graphene films grown on a Ni substrate by chemical vapor deposition. The technique used to produce transparent conductive films is facile, inexpensive and tunable for mass production.

To develop new type of high damping metal matrix composites, large grain size barium titanate (BaTiO₃) ceramic was sintered and added into Al powder to fabricate BaTiO₃/Al composites through the powder metallurgy method and hot extrusion. The damping properties of BaTiO₃ ceramic, Al matrix and BaTiO₃/Al composites were examined by dynamic mechanical analysis in the temperature range from 273 K to 573 K. The results show that although BaTiO₃ exhibits high damping (tan δ=0.12) below 400 K, the damping capacity of 10%BaTiO₃/Al (mass fraction) composites below 400 K is not increased as compared to the Al matrix. On the other hand, the damping capacity above 450 K is greatly enhanced due to the motion of dislocations at the interfaces between ceramic particles and Al matrix. The failure of exerting the intrinsic damping of BaTiO₃ particles in the composites is attributed to the poor interface bonding between the particles and the matrix. The tensile strength of the composite is 42% higher than that of the Al matrix, which indicates the possibility of obtaining high strength and high damping composites via interface improvement and the addition of high volume fraction of large grain BaTiO₃ particles.

A facile ultrasonic method was used to synthesize CoO/graphene nanohybrids by employing Co₄(CO)₁₂ as a cobalt precursor. The nanohybrids were characterized by SEM, TEM and XPS, and the results show that CoO nanoparticles (3-5 nm) distribute uniformly on the surface of graphene. The CoO/graphene nanohybrids display high performance as an anode material for lithium-ion battery, such as high reversible lithium storage capacity (650 mA∙h/g after 50 cycles, almost twice that of commercial graphite anode), high coulombic efficiency (over 95%) and excellent cycling stability. The extraordinary performance arises from the structure of the nanohybrids: the nanosized CoO particles with high dispersity on conductive graphene substrates are beneficial for lithium-ion insertion/extraction, shortening diffusion length for lithium ions and improving conductivity, thus the lithium storage performance was improved.

Flower-like CuO and flower-like CuO/graphene composite were prepared successfully by hydrothermal method. They were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, temperature-programmed reduction, and thermogravimetric analysis. It is found that the flower-like CuO microspheres, which are composed of CuO nanosheets, possess an average diameter of 4.2 µm and a Brunauer-Emmett-Teller surface area of 12.6 m²/g. Compared with the flower-like CuO, the obtained flower-like CuO/graphene composite shows an enhanced electrochemical performance with a higher capacity of 603 mA·h/g at 0.1 C rate and 382 mA·h/g at 1 C rate, and exhibits a better cycle stability with a high capacity retention of 95.5 % after 50 cycles even though at 1 C rate.

Nanosphere-like Li₂FeSiO₄/C was synthesized via a solution method using sucrose as carbon sources under a mild condition of time-saving and energy-saving, followed by sintering at high temperatures for crystallization. The amount of carbon in the composite is less than 10% (mass fraction), and the X-ray diffraction result confirms that the sample is of pure single phase indexed with the orthorhombic Pmn2₁ space group. The particle size of the Li₂FeSiO₄/C synthesized at 700 °C for 9 h is very fine and spherical-like with a size of 200 nm. The electrochemical performance of this material, including reversible capacity, cycle number, and charge-discharge characteristics, were tested. The cell of this sample can deliver a discharge capacity of 166 mA·h/g at C/20 rate in the first three cycles. After 30 cycles, the capacity decreases to 158 mA·h/g, and the capacity retention is up to 95%. The results show that this method can prepare nanosphere-like Li₂FeSiO₄/C composite with good electrochemical performance.

The LiMnPO₄/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance tests were adopted to characterize the properties of LiMnPO₄/C. The XRD studies show that the pure olivine phase LiMnPO₄ can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO₄/C well. The LiMnPO₄/C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA∙h/g, retaining 112.4 mA∙h/g over 30 cycles at 0.05C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO₄/C.

Spinel LiMn₂O₄ microspheres with durable high rate capability were synthesized by a facile route using spherical MnCO₃ precursors as the self-supported templates, combined with the calcinations of LiNO₃ at 700 °C for 8 h. The spherical MnCO₃ precursors were obtained from the control of the crystallizing process of Mn²⁺ ions and NH₄HCO₃ in aqueous solution. The effects of the mole ratio of the raw materials, reaction time, and reaction temperature on the morphology and yield of the MnCO₃ were investigated. The as-synthesized MnCO₃ and LiMn₂O₄ microspheres were characterized by powder X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Galvanostatic charge/discharge tests indicate that the spinel LiMn₂O₄ microspheres deliver a discharge capacity of 90 mA∙h/g at 10C rate show good capacity retention capability (75% of their initial capacity after 800 cycles at 10C rate). The durable high rate capability suggests that the as-synthesized LiMn₂O₄ microspheres are promising cathode materials for high power lithium ion batteries.

A vacuum directional solidification with high temperature gradient was performed to prepare low cost solar-grade multicrystalline silicon (mc-Si) directly from metallurgical-grade mc-Si. The microstructure characteristic, grain size, boundary, solid-liquid growth interface, and dislocation structure under different growth conditions were studied. The results show that directionally solidified multicrystalline silicon rods with high density and orientation can be obtained when the solidification rate is below 60 μm/s. The grain size gradually decreases with increasing the solidification rate. The control of obtaining planar solid-liquid interface at high temperature gradient is effective to produce well-aligned columnar grains along the solidification direction. The growth step and twin boundaries are preferred to form in the microstructure due to the faceted growth characteristic of mc-Si. The dislocation distribution is inhomogeneous within crystals and the dislocation density increases with the increase of solidification rate. Furthermore, the crystal growth behavior and dislocation formation mechanism of mc-Si were discussed.

The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting (SLM) technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.

A hip joint simulator was employed to predict the clinical wear behaviour of carbon/carbon (C/C) composites with needled carbon cloth preform and carbon felt preform. Wear particles generated from the two kinds of C/C composites were isolated and characterised by the size distribution and morphology. The evolvement of wear particles in the hip joint simulator was proposed. The results show that the wear particles from two kinds of C/C composites have a size ranging from submicron to tens of micrometers. The wear particles have various morphologies including broken fiber, fragment fiber, slice pyrolytic carbon and spherical pyrolytic carbon. C/C composites with needled carbon cloth preforms have larger size range and more broken fiber particles and slice pyrolytic carbon particles in comparison with C/C composites with carbon felt preforms. The evolvement of pyrolytic carbon particles is caused by surface regularization, whereas, the evolvement of carbon fiber particles is related to stress direction in the hip joint simulator.

Novel headstand pyrocarbon cones (HPCs) with hollow structure were developed on the surfaces of pyrocarbon layers of the carbon/carbon (C/C) composites at 650-750 °C by the electromagnetic-field-assisted chemical vapor deposition in the absence of catalysts. The fine microstructures of the HPCs were characterized by high-resolution transmission electron microscopy. The results show that the textural features of the HPCs directly transfer from turbostratic structure in roots to a well-ordered high texture in stems. And the degree of high texture ordering decreases gradually from the stem to the tail of the HPCs. The formation mechanism of the HPCs was inferred as the comprehensive effect of polarization induction on electromagnetic fields and particle-filler property under disruptive discharge.