Nanocomposite Ti-Si-N thin films have been deposited on Si (100) substrate by direct current/radio frequency (DC/RF) magnetron sputtering. The effect of varying deposition parameters on the structure and mechanical properties of Ti-Si-N films has been investigated by characterization techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and nanoindentation, respectively. XRD analysis of the thin films exhibit all (111), (200) and (220) peaks initially with varying sputtering pressure, but (111) peak dominates at higher sputtering pressure. The crystallite size calculated from XRD peaks shows that it increases with increasing sputtering pressure. Microstructural analysis reveals that the dense blurred grains transform into uniform grains in the films and shows porosity with increasing sputtering pressure. The surface roughness of the Ti-Si-N films increases with varying sputtering pressure. The hardness and Young0s modulus values of Ti-Si-N films are 33.7 and 278.6 GPa, respectively, with 0.7 Pa sputtering pressure but it decreases with further increase in sputtering pressure due to an increase in porosity of the films.

The (Bi_0.9Ho_0.1)_3.999Ti _2.997 V_0.003O₁₂ (BHTV) films have been prepared on Pt/Ti/SiO₂/Si substrates by solgel method. The microstructure and ferroelectric properties of the BHTV films were investigated. The BHTV films show a single phase of Bi-layered Aurivillius structure and dense microstructure. The Ho³⁺/V⁵⁺ cosubstitution can effectively improve the ferroelectric properties. The BHTV film exhibits good ferroelectric properties with 2Pr of 47.6°C/cm², 2Ec of 265 kV/cm (at applied field of 420 kV/cm), dielectric constant of 305, dielectric loss of 0.031 (at 1 MHz), good insulting behavior, as well as the fatigue-free behavior.

Ferrite compound Co_0:6Zn_0:4NixFe_2-xO₄ was synthesized by solid state reaction. The structure and performance of Co_0:6Zn_0:4Ni_xFe_2-xO₄ compounds were studied by MÄossbauer spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared radiant tester. MÄossbauer spectroscopy and XPS analysis show the valence states and distribution of cations in Co_0:6Zn_0:4Ni_xFe_2-xO₄. Zn²⁺ has invariably shown preference for the tetrahedral sites, and Ni²⁺ has the preference for the octahedral sites. The occupancy of Fe³⁺ linearly increases on the tetrahedral sites, and sharply decreases on the octahedral sites with increasing x, owing to its gradual replacement by Ni²⁺ on the octahedral sites. It indicates that due to the occupation of octahedral sites by the majority of Ni²⁺, Fe³⁺ decreasingly migrated from the octahedral sites to the tetrahedral sites and substituted Co³⁺ sites, which made the number of Co³⁺ in the tetrahedral sites decreasing. According to the measurement results of XRD and the infrared radiant tester analysis, the lattice parameter and infrared radiance have shown a nonlinear variation, exhibiting the infrared average radiance of 0.92 in the 8-14 μm waveband, and the results demonstrate that these Co-Zn-Ni spinel ferrites have potential for application in a wide range of infrared heating and drying materials.

Reaction synthesis process has been used to develop γ titanium aluminide using elemental powders. Powder mixture of Ti-48 at. pct Al was prepared in ball mill and reaction synthesis was carried out in hot press with varying temperature and pressure. Titanium aluminide synthesized under high pressure and temperature resulted in better properties with respect to densification, homogenization response, mechanical properties and oxidation resistance as compared to that synthesized under low pressure and temperature. Al rich phases were observed in as-synthesized condition in all the experiments. However, some Ti rich phases were also found in high pressure-temperature synthesized samples. Density, hardness and tensile strength have been correlated with applied pressure through empirical relations. Variation in density with pressure is found to be logarithmic whereas hardness and tensile strength variation with pressure is polynomial.

Pt/C catalysts were prepared by ethylene glycol (EG) method in weakly acidic solutions adjusted by sodium citrate (Na₃Cit), sodium acetate (NaAc) and sodium hydroxide (NaOH), separately. The e®ects of alkalizing agent, pH and temperature were investigated by transmission electron microscopy (TEM) and CV. The composition and structure of Pt/C catalyst prepared at optimal conditions of 140°C and pH=6.7 adjusted by Na₃Cit was further characterized by X-ray photoelectron microscopy (XPS) and X-ray diffraction (XRD), respectively. The average particle size of Pt/C catalyst prepared using Na₃Cit is 2.1 nm, smaller than that of Pt/C catalyst (2.9 nm) prepared using NaAc, much smaller than that of Pt/C catalyst (100 nm) prepared using NaOH. The electrocatalytic activity of Pt/C catalysts prepared using Na₃Cit and NaAc for ethanol oxidation are 456.6 and 419.2 mA/mgPt, comparative to those of Pt/C catalyst prepared by typical EG method and commercial E- TEK Pt/C catalyst. Finally, the size control mechanism of Pt nanoparticles was discussed.

Monodisperse spherical SiO₂ particles were successfully synthesized in 2-propanol-H₂O-NH₃ system by the microwave hydrothermal method using ammonia as catalyst. To investigate the influences on the size of spherical SiO₂ particles, factors such as ammonia concentration, reaction temperature, stirring intensity and reactants mol ratio have been studied. The orthogonal experiments were carried out. The as-prepared SiO₂ particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and differential thermal analysis (DTA). The results indicated that the size of SiO₂ particles increased greatly with the increase in ammonia concentration, temperature and reactants mol ratio, but increased slightly with the increase in stirring intensity. Monodisperse spherical SiO₂ particles were amorphous with perfect sphere and uniform size. Hydroxyl was detected in SiO₂. Kinetic parameters were calculated, and finally the reaction rate equation of dehydrated hydroxyl was obtained.

Al₂O₃-SiC composite was synthesized with pyrophyllite and natural graphite as raw materials by carbothermal reduction reaction under argon atmosphere. The effect of synthesis temperature on phase composition and microstructure was investigated. Low-carbon MgO-C refractories were prepared by using the synthesized Al₂O₃-SiC composite as additive. The effect of its addition on the slag penetration and corrosion resistance as well as oxidation resistance of the refractories was investigated, and the slag resistance and oxidation resistance mechanisms of the Al₂O₃-SiC composite were also discussed. The results show that the synthesis temperature has a great influence on preparation of Al₂O₃-SiC composite. The Al₂O₃-SiC composite can be synthesized at 1873-1973 K under argon atmosphere, with pyrophyllite and natural graphite as raw materials, and particle sizes of the composite synthesized at 1973 K are mainly distributed as 1-2 μm. The slag penetration and corrosion resistance of low-carbon MgO-C refractories can be remarkably improved by adding the synthesized Al₂O₃-SiC composite, and the oxidation resistance has an improvement to some extent. The increase of slag viscosity and the formation of MgAl₂O₄ can effectively inhibit the slag penetration and corrosion for the refractories.

Strontium doped perovskite-type Nd0:7Sr_0:3MnO₃ ceramics were synthesized completely by high-energy ball milling raw oxides of Nd₂O₃, SrCO₃ and MnO₂. The optimal ball milling time and mass ratio of milling balls to raw materials are 4 h and 10:1, respectively. The grain size of as-milled Nd0:7Sr_0:3MnO₃ ceramics ranges from 51 to 93 nm, and the fine particles contain two phases of crystalline phase and amorphous phase. For the Nd_0:7Sr_0:3MnO₃ synthesized by ball milling and sequent heat treatment, a remarkable colossal electroresistance (CER) effect is observed and the CER ratio reaches 900% at Curie temperature TC when the load voltage increases from 0.1 to 0.8 V.

The objective of this paper was to predict the residual strength of post impacted carbon/epoxy composite laminates using an online acoustic emission (AE) monitoring and artificial neural networks (ANN). The laminates were made from eight-layered carbon (in woven mat form) with epoxy as the binding medium by hand lay-up technique and cured at a pressure of 100 kg/cm² under room temperature using a 30 ton capacity compression molding machine for 24 h. 21 tensile specimens (ASTM D3039 standard) were cut from the cross ply laminates. 16 specimens were subjected to impact load from three different heights using a Fractovis Plus drop impact tester. Both impacted and non-impacted specimens were subjected to uniaxial tension under the acoustic emission monitoring using a 100 kN FIE servo hydraulic universal testing machine. The dominant
AE parameters such as counts, energy, duration, rise time and amplitude are recorded during monitoring. Cumulative counts corresponding to the amplitude ranges obtained during the tensile testing are used to train the network. This network can be used to predict the failure load of a similar specimen subjected to uniaxial tension under acoustic emission monitoring for certain percentage of the average failure load.

This paper investigated the uniaxial mechanical properties of a new type of hollow sphere structures. For this new type, the sphere shell was perforated by several holes in order to open the inner sphere volume and surface. The mechanical properties, i.e. elastic properties and initial yield stress of perforated hollow sphere structures (PHSS) in a primitive cubic arrangement were numerically evaluated for different hole diameters and different joining techniques of the hollow spheres. The results are compared to  classical configurations without perforation.

Effects of electromigration on microstructure, shear strength, and fracture behavior of solder joints were investigated by single-ball shear samples of eutectic Sn-3.8Ag-0.7Cu (SAC) joined by Cu plates at two sides. The electromigration tests were conducted at a current density of about 1.1×10³ A/cm² and a working temperature of about 83°C. The results showed that the shear strength and flow stress decreased greatly after current stressing. Such a decrease was associated with no significant loss of the fracture strain at short electromigration but a great reduction in the fracture strain after long-term current stressing. The variation of the fracture strain with the electromigration time was shown to result from the shift of the fracture surface from the center of the solder towards the intermetallic compound (IMC) interface at the cathode.

In order to join the similar magnesium alloy, a novel Zn-Mg-Al filler metal was designed and applied to braze AZ31B plates by using high-frequency induction brazing technique. The microstructure, phase constitution and fracture morphology of the brazed joint were investigated. The experimental results show that MgZn₂ phase in the original filler metal is completely consumed in the brazing process. Moreover, α-Mg solid solution and α-Mg+MgZn eutectoid structure formed in the brazing region due to the intensive alloying between the molten filler metal and the base metal in the brazing process. Test results indicate that the shear strength of the brazed joint is 56 MPa. The fracture morphology of the brazed joint shows intergranular fracture mode, where crack originates from the hard α-Mg+MgZn eutectoid structure.

The characterization of microstructure evolution in friction stir welded aluminum alloy was carried out by optical microscopy (OM) and transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). The weld nugget consisted of very fine equiaxed grains and experienced dissolution of nearly half of metastable precipitates into the matrix during welding. Thermomechanically affected zone (TMAZ) also experienced dissolution of precipitates but to a lesser extent whereas coarsening of precipitates was observed in heat affected zone (HAZ). Grain boundary misorientation measurements using EBSD indicated continuous dynamic recrystallization as the underlying mechanism for the fine equiaxed nugget grains. The yield and tensile strength of the weld decreased with comparison to base material. But due to the decrease of grain size and the dissolution of second phase precipitates, an increased Charpy energy value was observed in the weld nugget.

The biocompatibility of surface-modified biphasic calcium phosphate (mBCP)/poly-L-Lactide (PLLA) biocomposite was investigated through a series of experiments in vitro and in vivo. Acute toxicity and short term systemic toxicity experiments revealed no toxicity of the materials. Hemolysis assay indicated the good blood compatibility of the composite. In cytotoxicity assay, L929 mouse fibroblasts could well differentiate and proliferate. Animal experiments in vivo were performed by implanting the materials into rabbits muscle for 8 weeks. The decreasing of inflammatory cells, the building of fibrous tissue layer as well as the growing of blood cells into materials indicated the nontoxicity of the composite. Based on the experiment results, surfacemodified BCP/PLLA biocomposite is proven to have superior biocompatibility, which would be a promising bone repairing material.

With the help of electron back scattering diffraction techniques and field emission microscope, the misorientation and the precipitation environment of Goss grains in conventional grain-oriented steel were observed and investigated at the initial stage of secondary recrystallization. It reveals that the abnormal Goss grains have a high fraction of high angle boundaries ranging from 25 to 40 deg. The most important observation is that some of {110}<001> grains in matrix indicated higher particle density than their neighbor grains during final annealing at 875°C before secondary recrystallization, which could create a favorable environment for their abnormal grain growth. Based on misorientation and precipitation results, the abnormal growth mechanism of Goss grains was sketched.

This study dealt with the electrostrictive responses of polyurethane (PU) actuators with different microphase separation structure, which was a promising candidate for a material used in polymer actuators. In order to construct PUs with different higher-order structure, PUs with various types of polyol were synthesized: poly(neopentyl glycol adipate) (PNAD), poly(tetramethylene glycol) (PTMG), and poly(dimethyl siloxnae) (PDMS). Synthesized PU was characterized by Fourier transform-infrared (FT-IR) spectroscopy and gel per-meation chromatography (GPC). Thermal analysis and mechanical properties of PU films were carried out with differential scanning calorimetry (DSC) and UTM (universal testing machine), respectively. And PU actuator was formed in a type of monomorph, which was made by carbon black electrodes on the both surfaces of PU film by spin coating method. Actuation behavior was mainly influenced on microphase separation structure and mechanical property of PU. In result, PU actuator with PNAD, polyester urethane, had the largest field-induced displacement.