The study of the structural characterizations, physical properties and fabricated methods on the Si--based nanometer materials has attracted much attention because of their potential applications in the optoelectronic--integrated technology. Self--assembled growth methods are of increasing interest as a main formed technology of high quality nanostructures such as nanoquantum dots, nanoclusters and nanoscale films. In particular, self--assembled formations of the nanometer materials with controlled crystallite size and density distribution are very important for optoelectronic device applications. Two routes for the fabrication of these materials were proposed in this paper. First, controlling the orderliness of preferential nucleated sites on solid--state surface can obtain the materials. Second, controlling the orderliness of nucleated process during self--assembled growth will form them. New progress of these fabricated methods was reviewed, and the tendency of development in the near future was predicated.

The dynamic impact compression experiments for the X70 pipeline steel in rolling condition were carried out using the Hopkinson pressure bar. The structural evolution occurred during the plastic deformation under high strain rate, and the dynamic stress--strain behavior were investigated. The results show that the acicular ferrite dominated microstructure can be obtained for the X70 pipeline steel through rolling processing, and a lot of dislocation cells form in the ferrite laths and the ferrite laths are remarkably fragmentated under the strain rate lower than 2.5$\times$10$^{3}$s$^{-1}$, which leads to the increase in both the strength and the plasticity of the steel.

The textures of AZ31B magnesium alloy sheets in the conditions of hot rolling, cold rolling and heat treatment were investigated, and its feature and influence to the mechanical property anisotropy were studied. The conclusions show that the texture of rolled magnesium alloy sheet prefer to basal texture with basal plane parallel to sheet surface, while other compositions of texture are relatively weaker; the density center of basal pole rotates away by about 18$^{\circ}$ from the transverse direction of sheet to rolling direction; to cold--rolling of sheet, there is no significant change of texture distributing after heat treatment at 300℃. After cold--rolling of sheet, the basal plane slopes to rolling direction, improving the ductility in this direction.

Shot--peening and ion implantation were adopted to treat the surface of the machined specimens of Ti--6--22--22 alloy, and the stress controlled fatigue tests were performed at room temperature and 400℃, respectively. Experimental results indicated that the effect of shot--peening and ion implantation on the $S$--$N$ curves is related to temperature. Both shot--peening and ion--implantation have little effect on the fatigue strength at room temperature, but substantially increase the fatigue strength at 400℃ comparing with the untreated counterparts. SEM fractography surface analysis indicates that fatigue cracks of the treated samples initiate at ~subsurface after long--time fatigue at 400℃

The effects of electric field on recovery, recrystallization and texture of cold rolled Al--Mn--Mg alloy sheets were investigated by TEM and X ray analysis (ODF). The results show that when the intensity of electric field changes between 2 and 3 kV/cm, the electric field has no obvious effect on recrystallized progress of the cold--rolled Al--Mn--Mg alloys sheets. When the intensity of electric field was 4 kV/cm, it retards the recovery and recrystallization significantly. So It is believed that there is a threshold value (3 $\sim$4 kV/cm ) which decides the effect of electric field on recrystallization. The effects results from that the electric field retards the mobility of dislocation. Furthermore, the electric field annealing reinforce the cube texture of this sheet.

The compression and shear capacities of Al alloy foam and Al foam were studied. The failure modes and peak loads of sandwich beams with this Al alloy foam core were measured which was in good agreement with theoretic values. A design method is given which shows that rigidity is used as design controlling index for a low given load while relative peak load is used as controlling index for a high load. Comparison is made between the sandwich beams with the two different cores. It is concluded that sandwiches with Al alloy foam core have a rigidity 0$\sim$0.185 times higher than sandwiches with Al foam core, and a peak load 0.57$\sim$1.8 times higher under core--shear mode and 0.9$\sim$2.2 times higher under indentation than sandwiches with Al foam core.

Magnetic microspheres were prepared through partial reduction--precipitation method. The surface of particles was modified by silane--coupling agents. The structure and properties of these magnetic microspheres were characterized by X--ray, TEM, AFM, IR, etc. The magnetic nanoparticles modified by silane-- coupling agents present favorable dispersibility, responsibility to magnetism and resist against the corrosion of acid or alkali solution. The results of investigation on modified nanoparticles with different silane--coupling agents also indicate that the particles have multi functional organic groups on their surface, such as --OH, --NH$_{2}$, --NH, --C=O, --C=C.

Magnetic textured structures of MnBi precipitated phase in Bi--6\% Mn alloy were studied experimentally during solidification of the alloy from the semi solid zone below 446℃. An abrupt shape change of MnBi phase from regular hexagonal grains to oblate grains grown up along their ab--plane was observed firstly near 340℃, which is the transformation temperature of MnBi compound from paramagnetic state to ferromagnetic state. After the production of ferromagnetic MnBi grains from the magnetic transformation, the textured structures form by the rotation of the precipitated grains. The critical magnetic flux intensity for the textured structures decreases with increasing the heating temperature during solidification from the semi solid zone below 355℃ and increases between 355℃ and 446℃. Solidification from the semi solid zone below 355℃ is propitious to fabricate hypereutectic Bi/MnBi magnetic composites with excellent properties.

Scanning force microscope (SFM) was applied to observe the ferroelectric domains of PZT ceramic with rough surface. Domains in-plane and out-plane were detected using piezoresponse in longitudinal and transverse directions, respectively. The influence of the big grains on the imaging of the ceramic surface was investigated. A method in which exact 3D domain structure of coarse sample can be obtained was suggested. Different from other methods of observing ferroelectric domains, PFM was adapted to the ferroelectric bulk ceramic that had never been polished. The as--grown domain structure was observed. The observation of domain in PZT ceramic confirms that the main reason for the formation of domain in grains with less stress is the decreasing of depolarization energy, while that in grains with bigger stress is the decreasing of strain energy.

A series of biodegradable crosslinking agents, di--acrylate of polyethylene glycol and polylactides (PLA--b--PEG--b--PLA) tri--block copolymer, were synthesized. And then the novel biodegradable crosslinked PVP membrane materials were prepared by radical polymerization with biodegradable crosslinking agents and N--vinyl pyrrolidone (NVP) using azoisobutyronitrile (AIBN) as initiator. The performance of PVP membrane materials was investigated. The results showed that the intrinsic viscosity of crosslinking agents would be regulated by changing the ratio of lactide to PEG. The water absorption would decrease, while the contact angle and the tensile module would increase with increasing the content of crosslinking agents, but extension at break would increase at first and decrease at last. The water absorption and the contact angle would increase with increasing the molecule weights of crosslinking agents. In the degradation process, the mass--loss rate of the materials showed specific original kinetic in the initial duration, but it increased dramatically at last.

The influence of lithium on the ageing behavior and microstructure of the low Cu/Mg ratio Al--Cu--Mg--Ag alloys was investigated. The results show that the effect of Li is to increase the rate of hardening, however, the addition of lithium does not progressively change age hardening and precipitation process of Al--Cu--Mg--Ag alloys with low Cu/Mg ratio, and significant age hardening response only occurs with the addition of 2.0\%Li (mass fraction). Transmission electron microscope (TEM) investigation results show that the remarkable increase of age hardness and strength is attributed to the fine dispersion of $\delta^{\prime}$, $Z$ phase and spherical $\delta^{\prime}$/$\beta^{\prime}$ compound particles in the 2.0\%Li--containing alloy.

(Na$_{0.5}$Bi$_{0.5}$)$_{1-x}$Ba$_{x}$TiO$_{3}$ fine powders were synthesized by a citrate method. The piezoelectric properties of (Na$_{0.5}$Bi$_{0.5}$)$_{1-x}$Ba$_{x}$TiO$_{3}$ ceramics were investigated. The results show that the mole ratio of citric acid to total metal cation content (C/M$^{n+}$) and pH value of precursor solution are main contributing factors to the formation of sol and gel. The fine powders with a pure perovskite structure can be obtained from the gel by calcining at 600℃. The powders synthesized by the citrate method exhibit fine morphology and high chemical homogeneity, thus enhancing the piezoelectric properties of (Na$_{0.5}$Bi$_{0.5}$)$_{1-x}$Ba$_{x}$TiO$_{3}$ ceramics. (Na$_{0.5}$Bi$_{0.5}$)$_{1-x}$Ba$_{x}$TiO$_{3}$ ceramics with the compositions near the morphotropic phase boundary (MPB) show superior piezoelectric properties due to the existence of more spontaneous polarization directions. A high piezoelectric constant $d_{33}$ of 180 pC/N was obtained for (Na$_{0.5}$Bi$_{0.5}$)$_{1-x}$Ba$_{x}$TiO$_{3}$ ceramics when $x$=0.06.

The vacuum thermo--cycling(93$\sim$413 K, 10$^{-5}$Pa) was performed on unidirectional M40J/5228A composites, and the 90$^{\circ}$ and 0$^{\circ}$ tensile strengths, bend strength and interlayer strength were examined after vacuum thermo-cycling for various cycles. The fracture of surfaces of the specimens was observed by SEM. The influence of vacuum thermo--cycling on the mechanical properties of the M40J/5228A composites was investigated. The results show that with increasing the thermal cycles, both the 90$^{\circ}$ and 0$^{\circ}$ tensile strengths decrease and tend to level off after the cycles of 48 and 40, respectively. The bend strength shows a trend of ascending followed by descending and leveling off, while the interlayer strength do not change a lot. The changes of the 90$^{\circ}$ and 0$^{\circ}$ tensile strengths could be related to the interface debonding. The thermo--cycling would cause additional curing of the epoxy matrix and affect the bent strength. The change in the interlayer strength depends on the combination of the interface debonding and the followed curing caused by the vacuum thermo--cycling.

The rich oxided Si nanocrystallites were formed on the surface of the traditional electrochemically--produced samples after being peeled off the surface porous film in the marinade. Photoluminescence (PL) was used to characterize the samples. Ultraviolet--blue PL intensity is about 10 times as much as that of the samples before being peeled off the porous film. The PL intensity is one third of the original intensity after annealed in O$_{2}$ at 300℃, and then becomes stronger along with the increase of the annealing temperature. There are different luminescence mechanisms of the samples before and after annealing, carriers are excited mostly in the Si nanocrystallites and radiative recombined in the SiO$_{2}$ layers before annealing; and carries are excited and radiative recombined both in the SiO$_{2}$ layers after annealing.

The influence of amount of CoSO$_{4}\cdot$6H$_{2}$O in electrolyte on chemical composition, microstructure and property of nanocrystalline Co--Ni alloy deposit layers prepared by jet electrodeposition was investigated. The results show that with the increase of stirring intensity of the electrolyte, the thickness of diffused layer decreases, the critical current density increases, and then the depositing rates increase. At the same time, the increase of over--potential results in the nucleating rate and the micro--hardness of deposits increasing, while the grain size deposits decreasing. Co content in deposits increases with increasing the Co$^{2+}$ content in electrolyte, which results in the change of the microstructures in deposit layers from face--centered cubic $\alpha$--Co(Ni) to mixture of face--centered cubic $\alpha$--Co(Ni) and hexagonal close--packed $\varepsilon$--Co(Ni), and the change of morphology of surface of deposit layers.

Two--dimensional displacement discontinuity boundary element method was applied to simulate the mechanical behavior of brittle disordered materials, assuming that the specimens contain identical micro--crack density but with different degrees of disorder of micro-crack size distributions. The micro--mechanism for the size effect of the brittle or quasi--brittle disordered materials is explained by a new point of view of fractal geometry. The numerical simulation results are in good agreement with the Bazant size effect law. The size effect, which is more significant as the degrees of disorder of micro--crack size distribution increases, is related to not only the micro--defects density, but also the degrees of disorder of micro--crack size distribution. In addition, an empirical expression relating the fractal dimension of fracture surface with initial fractal dimension was obtained, which can be used to explain the micro--mechanism of size effect and the micro--crack evolution processes more deeply.

Two kinds of master batches of carbon nanotubes (CNT) were obtained by dispersing CNT in dispersing agent and polymer (PA6) carrier or in dispersing agent, then CNT reinforced PA6 fibers were obtained by blending melt spinning of PA6 and CNT master batches. The mechanical property and structure of the fibers were also studied. When the CNT content (mass fraction)in fiber is lower than 0.5\%, the strength and modulus of the fibers are higher than that of pure PA6 fiber, and the fibers with 0.03\% CNT have the best strength and modulus. The effect of master batch consisting of carbon nanotubes and dispersing agent is better, and at 0.03\% CNT adding, the strength and modulus of the PA6 fiber with this master batch increase by 23\% and 76\%, respectively. The reinforced PA6 fibers are fibril--reinforced fibers. Carbon nanotubes exhibit good dispersion in the PA6 matrix and orient along the fiber axis. This structure can transfer the load effectively and the effect of reinforcement will be improved with the degree of orientation of CNT in the fibers increasing.