Abstract: DFR facing whole remanufacturing process is an essential premise for remanufacture engineering development, which relates to lots of research contents and engineering technologies. The connotation of DFR including the conception, task, target and characteristic are given and described in this paper, then the research content and system framework of DFR are put forward, finally some key technology units of DFR are explained in detail.
Abstract: Nanocrystal TiO2 photocatalystic materials were prepared by melt-phase separation technique, and its preparation principle was discussed in this paper. Anatase nanometer TiO2 could be obtained by heat-treatment at 550 °C for 10 min, which is well combined with porous glass carrier and the particles size is about 25 nm. The growth kinetics of TiO2 crystalline analysis results showed that the growth activation energy Q1 was about 63.27 KJ/mol (<600 °C), and Q2 was about 22.78 KJ/mol (>600 °C).TiO2 crystalline growth closely related to glass phase separation. TiO2 particles grew quickly with the glass phase separation size increase, and then the particles growth rate became slow because of being limited by glass phase separation structure.
Abstract: ZnO nanowires with the diameters ranging from 20 to 40 nm and lengths in the range 3-5 μm were synthesized on ITO coated glass substrate by a low temperature (80 °C) solution method. The average aspect ratio (h/r) reached 150. Owing to the van der waals force the neighborly nanowires close up to form tower-like ZnO bundles. The field emission of the ZnO bundles shows a turn-on field of 7.1 V/μm at a current density of 10 μA/cm2. The threshold field is 11.3 V/μm at a current density of 10 mA/cm2. The good field emission performance is attributed to the high aspect ratio and tower-like shape.
Abstract: FAU-type(NaY) zeolites nanocrystals have been synthesized through crystallization of gel in mesoporous system of carbon nanotubes(CNTS) with a internal diameter of 20~30 nm. Investigation by using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscope (TEM) shows that the nanocrystals possess the typical nanosized zeolites structural characteristics which is different from those of microsized zeolites.
Abstract: Electroless metal deposition is a simple, low-cost and effective method for fabricating silicon nanowire arrays and has been used widely in micro electromechanical industry. In this paper, large-area silicon nanowire arrays are prepared successfully with mixed AgNO3 and HF solution by this method at normal temperature and pressure. It has been proved the best equality of silicon nanowires can be obtained at the concentration ratio of 0.02 mol/l: 5mol/l for AgNO3 and HF and 1h reaction time. The influence of nano metal particles on the growth, the wire diameter, the distribution and the array of silicon nanowires are analyzed. Experimental results show the distribution and wire diameter of silicon nanowires can be controlled effectively by nano metal particles deposited on silicon wafers. The length of silicon nanowires increases with the reaction time and the average growth velocity is predicted to be 0.5～0.7μm/min. The equality of silicon nanowires with nano Au particles is better than those with nano Pt particles. The reaction mechanism of preparing large-area silicon nanowire arrays is analyzed as the result of the deoxidization of silver ion and the removal of the oxidized silicon solution by reacting with HF.
Abstract: The hot-pressing technology for the poplar particle /waste rubber powder composites was studied using the poplar particle and waste rubber powder as raw materials. Effects of waste rubber powder content, hot-pressing time, hot-pressing temperature, resin content and board density were analyzed. The hot-pressing technology was better than molding technology. The optimal technological parameters of hot-pressing technology were obtained as board density0.8g/cm³, resin content3%, hot-pressing temperature160°C, hot-pressing time 7min , waste rubber powder content 30%. The testing results showed that the mechanical performances of the poplar particle /waste rubber powder composites made by the hot-pressing technology could achieve the Chinese National Standard for particle board.
Abstract: The bulk nano-crystalline cobalt-nickel alloys have been prepared by the double refined methods (DRM) combined the high-speed jet electrodeposition (JED) with the additive added in jet electrolyte, and their microstructure and properties, such as the microhardness and magnetic properties, have been evaluated. The results indicate that the DRM is a very effective technique for grain size refinement and property improvement. The concentration of the additive added in the jet electrolyte has little effect on the Co-content in the deposited alloys, but they have a remarkable effect upon the microstructure and properties.
Abstract: A coagulation method providing a better dispersion of nano-Antimony-Doped Tin Oxide (ATO) in a polymer matrix was used to produce nano-ATO/poly(methyl methacrylate) (PMMA) composites. Scanning electron microscopy showed an improved dispersion of nano-ATO in the PMMA matrix, which is a key factor to determine the composite performance. Moreover, the PMMA with the addition of nano-ATO showed improved electrical conductivity and thermal stability.
Abstract: Tadpole-like microstructures which consisted of silica nanowires have been synthesized on Si wafers at 950°C by using tin droplets as catalyst. Each tin droplet can simultaneously catalyzes the growth of many silica nanowires of each tadpole-like microstructure and can simultaneously catalyzes the growth of even two tadpole-like microstructures, which is quite different from the conventional vapor-liquid-solid process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses show that the tadpole-like microstructures with diameters of 5 μm and lengths of up to 50-100 μm. The amorphous silica nanowires with a composition close to that of SiO2 have diameters of 100–200 nm. The PL spectra of the SiO2 nanowires shows a strong emission peak centered at 390 nm (3.18 eV), while two weak PL peaks at 323 nm (3.84 eV), and 455 nm (2.73 eV) can also be observed. The growth mechanism of the tadpole-like microstructures was also investigated.
Abstract: Multiwalled carbon nanotubes (MWCNTs) have been successfully synthesized by using a relatively simple method, known as modified Wolff-Kishner reduction process. Transmission electron microscopy (TEM) has shown the as-prepared MWCNTs possess straight morphologies with average inner and outer diameters, between 2 to 7 nm and 5 to 15 nm, respectively. Ultraviolet-visible (UV-Vis) absorption measurement has been conducted for the first time. The correlation between energy of the π plasmon absorbance (Eπ) and nanotube diameter (dCNT) for the as-prepared MWCNTs shows contradiction to the empirical relationship as Eπ = 4.8 + 0.7 / (dCNT)2. Other optical characteristics like transmittance, reflectance and refraction index also have been studied. This work explores the optical property of the as-prepared MWCNTs and thus provides better understanding about the feasibility of this synthesis technique.