The P20 specimens were machined with different electrical discharging currents to investigate the effect of the pulse current on the micro structure and properties of the specimen surface. There are three layers on the specimen surface: ablation layer, molten layer and recrystallized layer. The thickness of the molten layer and recrystallized layer increases with the increment of the pulse current. The content of the oxygen and carbon element on the outside of the molten layer is higher than that in the base metal for the element diffuse during the machining. The micro hardness reduces from the out layer to the base metal for the heat treatment during the discharge machining. Micro fracture is found in the molten layer which is caused by the residual stress during the machining according the finite element analysis.

Quench sensitivity relative to exfoliation corrosion of 7085 aluminum alloy plate was investigated by means of end-quench test, corrosion immersion test, scanning electron microscopy(SEM), transmission electron microscopy (TEM). The results show that the resistance to exfoliation corrosion of 7085 aluminum alloy plate decreased with quench rate decreasing, from EA to EB and the maximum corrosion depth from 135 μm increasing to 315 μm, there is a liner relation between the corrosion depth and the logarithm of quench rate. With decrease of quench rate, the size of η equilibrium phase at grain boundaries increased, wider precipitate free zone near grain boundaries and some equilibrium η phase precipitate at sub-grain are primarily responsible for quench sensitivity relative to exfoliation corrosion.

Effect of normalizing temperature on the microstructure and mechanical properties of a martensitic heat resistant steel with high contents of silicon, chromium and carbon was investigated. It was found that carbides in the steel dissolved greatly above 980℃, additional expansion occurred on the thermal dilation curve and two forms of Cr₂₃C₆ were decorated along the lath boundaries after tempering. When normalized at 1030-1100℃, large size Cr₂₃C₆ carbides containing silicon precipitated along the grain boundaries. Tensile properties of the steel increased with normalizing temperature below 1030℃ and kept almost unchanged at higher normalizing temperatures. The toughness of the steel decreased with normalizing temperature and the large size chain-like Cr₂₃C₆ carbides along grain boundaries were the key factor to reduce the toughness.

Low cycle fatigue (LCF) behaviors of grey cast iron used for cylinder were investigated at room temperature (RT), 150℃ and 250℃. Tensile stress-strain curves, cyclic stress-strain curves and fatigue life curves were obtained. The results show that Young’s Modulus, proof strength and ultimate tensile strength of grey cast iron decreased with increasing temperature, while the elongation increased. Cyclic hardening/softening exhibited cyclic hardening initially, then softening and fracture at lower strain amplitudes, while it exhibited cyclic softening and fracture directly without cyclic hardening at 150℃, 250℃ and higher strain amplitudes. Fatigue life decreased with the increase of temperature and was lowest at 150℃. LCF cracks initiated predominantly at the flake graphite tip, near-surface defects such as inclusions and voids, and crack would propagate along graphite. Heterogeneous inclusions contributed crack deflection and bifurcation which would decrease the propagating rate. Crack propagation was mainly characterized by fan shaped cleavage plane, secondary cracks, fatigue striation and some dimples, which indicated the fractural mechanism is intergranular and quasi-cleavage cracks．

A novel flourene-alt-karbazole organic phosphorescenct polymers (PFCzIrpiq) containing a pendent phosphor chromophore of the (Piq)₂Ir(Pic) were synthesized via Suzuki coupling reaction. Their molecular mass was measured by gel permeation chromatograph, chemical structure was characterized by ¹H NMR, and the photophysical property, thermal stability and electrochemical property of these polymers were investigated by UV absorption spectra, fluorescence spectra, thermogravimetric analysis and cyclic voltammetry. Using the polymers as emitting layer, the devices were made with a configuration of ITO/PEDOT: PSS (50 nm)/ PFCzIrpiq (45 nm)/LiF(0.5 nm)/Al (150 nm), and their electroluminescent properties were measured. The results show that the molar percentage of (Piq)₂Ir(Pic) in these polymers has great influence on light-emitting color of these polymers. When the molar percentage was 1%, the device exhibited blue emission with a CIE coordinate of (0.22, 0.22); when the percentage was increased to 5%, the device emitted saturated red light with a CIE coordinate(0.65, 0.35). Furthermore, with the increasing of molar percentage of (Piq)₂Ir(Pic), the current density decreased and the maximum brightness increased gradually. When the molar percentage was 5%, the maximum brightness of 48 cd/m² was achieved.

The effects of carbonization temperature on the structural defects and mechanical properties were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and mechanical properties test. The results show that, in the stage of low temperature, strength and modulus both increase with temperature increasing, but they show different increasing rate lower and higher than that in 700℃. When temperature is lower than 700℃, the stress-strain curves demonstrate there are “zigzag” inflections due to rapid decreasing of stress without obvious yield. Above 700℃, yield appears prior and then inflection. In the stage of high temperature, the fracture of fiber presents typical characteristics of brittle material .The changes of mechanical properties are related to the changes of structure. The increase of strength is due to the crystallinity of quasi-crystal graphite, while the increase of modulus is mainly depended on the improvement and packing order of the quasi-crystal graphite. The fracture of carbonized fibers in 500-1350℃ mainly depends on the surface defects. The slender cracks along the fiber axis are both on the surface of carbonized fibers in 700℃ and 1350℃. The slender crack diameter of carbonized fiber in 700℃ is about 2 nm, and the length is from dozens of nanometers to hundreds of nanometers. The slender crack diameter of carbonized fiber in 1350℃ is about 1 nm, and the length is in the range of 50-190 nm. These slender cracks may be the main reason for the fracture of the fibers.

Dense TiB₂-TiC multiphase ceramics were prepared by pressureless sintering technique, starting as the powder mixtures obtained by high energy ball milling. The results show that the mechanical alloying was beneficial not only for the control of the microstructures and phase component of the TiB₂-TiC composites, but also for the formation of coherent interface between TiB₂ and TiC. The TiB₂-TiC composites sintered using the 48 h milled powder at 1800°C for 2 h have the optimum values of mechanical properties, such as densities greater than 98% of the theoretical value, higher bending strength (487 MPa), higher hardness (94.7, HRA), and fracture toughness (5.83 MPam^1/2).

In this paper, aligned multi-walled carbon nanotubes (A-MWNT) and non-aligned multi-walled carbon nanotubes(MWNT) of different volume fractions were dispersed into natural rubber (NR) via solution blending, and subsequently NR nano-composites were prepared through ambient cross-linking. Then the dispersions of A-MWNT and MWNT in rubber matrix were observed, and the effects of A-MWNT and MWNT on the glass transition temperature (T_g) of rubber composites, cross-linking heat release under high temperature and heat conduction performances were analyzed. Research showed that parts of the A-MWNT would be disorganized in the process of solution blending, ultrasonic oscillation and stir, be aligned in micro-area units but isotropic on the whole. As the fraction of A-MWNT increased, T_g gradually decreased then increased, heat release under high temperature gradually increased. Compared with composite materials filled with MWNT in the same condition, the thermal conductivity of the composites filled with A-MWNT increased quickly with the enhancement of A-MWNT fraction, jumping to maximum of 0.735 W/(mK) when filled with 10% A-MWNT, which was increased by 222.4%.

For the dissimilar joint of continuous drive friction welding, an analytical solution was proposed to predict the steady-state average temperature in the plastic region, which was resorted to the distribution coefficient of welding heat. The steady-state average temperature in the plastic region of two dissimilar joint TC4/TC17 and TC11/TC17 were calculated in the following cases: constant rotation speed but different welding pressures and constant welding pressure but different rotation speeds. The calculated average temperature was compared with the experimental temperature data. The results show that when the rotational speed is holding constant, the average temperature decreased with the increasing welding pressures, while when the welding pressure is holding constant, the average temperature increased with the increasing rotational speeds. When the welding parameter is holding constant, the average temperature of the TC17 side of dissimilar joints are always lower than that of the other side, whether TC4/TC17 or TC11/TC17 joint. The calculated temperature and the actual temperature agree well and the difference between them is less than 7% which shows the accuracy of the analytical solution.

Superparamagnetic iron oxide (SPIO) nanoparticles were synthesized by thermal decomposition of the iron(III) acetylacetonate (Fe(acac)₃) in poly(ethylene glycol) (PEG) containing poly(ethylene imine) (PEI) as modifying agents. The samples were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), superconductivity quantum interference device (SQUID), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), particles & zeta potential analyser, and small animal 7 T MR scanner. The results show that approximate equiaxial shaped nanoparticles have been obtained by the method, the size of nanoparticles increases from (5.2±1.0) nm to (10±1.7) nm and their crystallinity increases with increasing the synthesized temperature from 180℃ to 260℃, and the magnetite nanoparticles show superparamagnetic behavior at room temperature with high saturation magnetization. The surfaces of SPIO were modified by PEG and PEI which provided excellent water dispersibility and stability for a long time (more than 90 d). The T₁ and T₂ weighted MR images of 10 nm-sized SPIO synthesized at 260℃ showed good contrasting effect, exhibiting a low r₁ relaxivity of 1.65 mmolL^-1S^-1 and a high r₂ relaxivity of 142.99 mmolL^-1S^-1with a high r₂/r₁ ratio of 86.6. Magnetic resonance imaging in vivo demonstrated that the SPIO could be excellent T₂ contrast agents.

Quaternary kesterite Cu₂ZnSnS₄(CZTS) particles were successfully synthesized by a facile solvothermal method in ethylene glycol with the presence of different ratio of surfactant, using CuCl₂2H₂O、Zn(Ac)₂2H₂O and SnCl₄5H₂O as metal precursor and thiourea as sulfur source. Different morphologies CZTS particles were obtained by different contents of PVP and CTAB. The structure, morphology and absorption spectra of the as-obtained CZTS particles were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM) and UV-Vis spectroscopy. The results revealed that the structure of as-synthesized CZTS particles is kesterite; the morphology and optical band-gap of CZTS has occurred a certain change with different ratios of PVP and CTAB. When PVP and CTAB ratio of 3∶1 was added to the reaction system, uniform and mono-disperse flower-like CZTS particles were obtained, the band gap of the CZTS is about 1.48 eV, which approaches the optimum value for solar photoelectric conversion. Finally, a possible fabrication mechanisms of CZTS particles was also inferred.

The effect of applied voltage, collecting distance and extrusion speed on morphology of polyurethane fiber were systematically investigated. Polyurethane/ polyhedral oligomeric silsesquioxanes (PU/POSS) fibers were spun by electrospinning method with the conditions of 8% solution, 6 mL/h extruding speed, 30 kV voltage and 15 cm distance. The effect of POSS on morphology, mechanical and thermal properties of polyurethane fiber was studied. The average diameters of PU/POSS composite fibers increase compared to the pure PU fibers. The onset temperature of decomposition and glass transition temperature of PU/POSS composite fiber respectively increase by 22℃ and 15℃ than pure PU fiber. The mechanical properties of PU/POSS composite fiber was improved compared with pure PU fiber.

ZnO nanowires were prepared by crystal seed formation in situ and hydrothermal synthetic process in large-sized macroporous SiO₂ materials. The nanowires are formed by wurtzite ZnO crystal with a diameter of about 15—20 nm, which display a randomly-coiled morphology, good dispersion as well as stable structure. ZnO NWs/SiO₂ complex can effectively load Fe (Ш)-taPc to offer ternary composite photo-catalyst Fe(Ш)-taPc/ZnO NWs/SiO₂ with a maximum loading rate(mass fraction) of 11.5%. The photo-catalyst Fe(Ш)-taPc/ZnO NWs/SiO₂ was characterized by means of SEM, XRD, UV-Vis diffuse reflectance spectrometry and Raman spectrometry. The photocatalytic activity of the photocatalysts was also determined by using Rhodamine B as the objective substance. The catalyst exhibited good activity for the degradation of Rhodamine B under visible light, and the reaction followed first-order kinetic equation. The catalyst containing 3.5% of Fe(Ш)-taPc showed highest activity, and can degrade 98.6% of Rhodamine B within 60 min. The presence of ZnO NWs promoted the photocatalytic activity by an average of 77%. The activity decreased very slightly after six circular utilizations, showing that the catalyst was stable and reusable.

The aging strengthening law, mechanical properties, thermal stability and thermal conductivity of the hot stamping die steel SDK1 steel were investigated. The results show that after solution and aging treatment SDK1’s hardness is higher than that of high-quality H13 steel and impact energy is very close to that of the H13 steel. SDK1’s hardness is higher about 8HRC than that of H13 steel after heat treatment and hold at 620℃ for 20 h. The aging hardening of SDK1 steel mainly rely on precipitates dispersed nanoscale Cu and NiAl phases, which hold at 620℃ after 20 h with small dimensional changes. This is the reason of better stable performance of SDK1. The thermal conductivity of SDK1 steel is significantly higher than that of H13 steel in the temperature range of 100-700℃. It is connected with the low-containing elements Si and Cr in the alloy component of SDK1.

PbSO₄/activated carbon composite (PbSO₄/AC) was prepared by the processes of adsorption of Pb²⁺ and deposition of PbSO₄ on the surface of activated carbon. The composite was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The results showed that PbSO₄ crystals (about 200 nm) uniformly dispersed on the surface of the activated carbon particles and the content (mass fraction) of lead element in the sample was 26.43%. The electrochemical measurements in H₂SO₄ aqueous solution showed that PbSO₄/AC possessed high over-potential of hydrogen evolution, high electrical conductivity and could provided a certain degree of oxidation-reduction current. Moreover, the loss of non-faradic specific capacitance was small. The ultra-battery was fabricated in which the negative plate was prepared by adding 5% PbSO₄/AC (related to leady oxide) to the negative paste. Initially, the battery was discharged to 60%SOC and then subjected to the test of cycling performance at high rate. The cycle life of the ultra-battery was 3-4 times higher than that of traditional lead-acid battery.

PZT-Ag₂O ferroelectric films were prepared successfully on the transparent ITO conductive glass substrate. The phase structure and surface morphology of the thin films prepared on different substrate temperatures were investigated. The PZT-Ag₂O films showed good ferroelectric properties, and the ITO/PZT-Ag₂O/Pt diodes indicated excellent photoelectric response at the visible spectrum. More interestingly, its photo-generated short-circuit photocurrent and open-circuit voltage varied with the poling voltages, and it mainly attributed to the ferroelectric depolarization field in the poled PZT-Ag₂O films. A possible mechanism concerning the photovoltaic effect in the ITO/PZT-Ag₂O/Pt diode characteristics was discussed. The magnitude of depolarization fields is varied with the applied voltages, resulting in hysteresis loop between the photo-generated short-circuit photocurrent or open-circuit voltage and applied voltages.

Barium titanate (BaTiO₃) films were grown on the titanium alloy by micro-arc oxidation (MAO). The bioactivity of BaTiO₃ films after polarized was discussed. It was studied on the induced mechanism of HA formation. The results show that the bioactivity of BaTiO₃ films after polarization was obviously improved. In the SBF, the inducibility of BaTiO₃ films was higher than BaTiO₃ ceramics block, which was connected with polarity of BaTiO₃ films, rough and porous surface morphology, high surface area, and nanocrystalline characteristics. The cytotoxicity test showed that BaTiO₃ films prepared by MAO had good biocompatibility, the cytotoxicity of BaTiO₃ films were less than or equal 1, which accord with the clinical requirements. The films prepared at high voltage had higher cell proliferation ratio than those prepared at low voltage.

The moisture absorption and desorption behavior of CCF300/BA9916 composite laminates in 70℃ distilled water was investigated. After the moisture absorption and desorption experiments, the static tensile performances of CCF300/BA9916 composites in three conditions were investigated. The results show that the moisture absorption and desorption behavior of CCF300/BA9916 composites basically conforms the Fick’s second law. After 35 days of moisture absorption, the composites reach to the effective moisture equilibrium level, and the effective moisture equilibrium content is about 0.85%. Compared with the dry one, the static tensile performances of CCF300/BA9916 composite laminates decreased due to moisture absorption, while the desorption process makes it some recovery.