Advanced Materials Research Vols. 284-286

Abstract: The reactively sputtered HfO₂ and HfSi_xO_y dielectrics have been investigated comparatively for metal-insulator-metal (MIM) capacitor applications. X-ray photoelectron spectroscopy analyses reveal the presence of Hf-O, Hf-O-Si and Si-O chemical bonds in the HfSi_xO_y films as well as lots of oxygen vacancies. The relative concentrations of Hf-O-Si and Si-O bonds increase with an increment of the power applied to the Si target. Further, it is found that the quadratic voltage coefficient of MIM capacitor decreases with increasing the Si content in the HfSi_xO_y dielectric in despite of a decrease in the resulting capacitance density. The HfSi_xO_y dielectric MIM capacitors with a capacitance density of ~8.4fF/μm² exhibit a quadratic voltage coefficient of 1840 ppm/V² at 100kHz, which is much smaller than 2750 ppm/V² for the HfO₂ dielectric MIM capacitors with a density of ~11.8fF/μm².

Abstract: Hollow TiO₂ nanospheres have been successfully prepared by templating the polymericmicelles of poly (styrene-b-[3-(methacryloylamino)propyl] trimethylammonium chloride- b-ethylene oxide) (PS-b-PMAPTAC-b-PEO), which shows a core-shell-corona structure in aqueous solutions. It was found that, in such system, the wall thickness of the hollow TiO₂ is fine tuned by varying the concentration of the TiO₂ precursor.

Abstract: The Cu-based friction materials with nano-graphite were prepared through powder metallurgy technology. The microstructure and friction performance were studied through scan electronic microscope (SEM) and friction tester, respectively. The results indicate that coefficient of the Cu-based friction materials with 2 wt% nano-graphite is high and stable. Comparing with the friction materials without n-C, the wear resistance and heat resistance of the friction materials with nano-graphite has been improved by 11 % and 25 %, respectively. The nano-graphite particles will reduce the abrasive wear and enhance the wear resistance of the Cu-based friction materials.

Abstract: Using a long alkyl-polyamine triethylene-tetramine as structure-directing agent, FeZSM-35 zeolites were synthesized and characterized by XRD, SEM, FTIR and TG-DTA techniques. EDS and ICP-AES indicate that the transition metal iron ions were framework elements and the mass fraction was 0.48%. The catalytic activity of as-synthesized crystals was examined for the aqueous hydroxylation of phenol with hydrogen peroxide. The phenol conversion was 18.8% and the selectivity on catechol and hydroquinone was ca. 69.1% and 30.9%, respectively. The as-synthesized FeZSM-35 zeolites show relative high selectivity towards catechol and could be a promising catalyst.

Abstract: The severe plastic deformation (SPD) procedure designated continuous confined strip shearing (CCSS/C2S2) technique based on rolling, equal channel angular pressing (ECAP) and Conform principle was simulated numerically by using finite element code DEFORM-3D. The influences of rolling reduction ratio on restoration ratio of work-piece geometry, effective strain, output velocity of processed work-piece, torque of rollers, and energy consumption feature for the C2S2 procedure were investigated. The results show that rolling reduction ratio has significant influences on C2S2 procedure. With the increase of rolling reduction ratios (5%, 10% and 20%), the restoration ratio of work-pieces geometry reduced, the magnitude of effective strain kept almost unchanged, the output velocity of processed work-piece increased, the total torque of rollers decreased, and the energy consumption used for making unit volume work-piece subjected to unit straining reduced considerably. It was found that the optimal rolling reduction ratio was about ~10 %, where the energy consumption reduced by 8.16 %, whereas the restoration ratio of work-piece geometry was almost the same as constrasting with the rolling reduction ratio of 5 %.

Abstract: Multi-walled carbon nanobutes (MWNTs) reinforced epoxy resin nanocomposites were fabricated by functionalizing the MWNTs with amino group. The functionlization of MWNTs was characterized by FTIR, elementary analysis, and TEM, and the MWNTs dispersion was characterized by optical microscopy and SEM. MWNTs functionalization with ethylene diamine improved the nanotube dispersion in the epoxy matrix composites. The dynamic mechanical thermal properties and thermal properties of MWNTs/epoxy nanocomposites are briefly discussed in terms of the MWNT loading and dispersion.

Abstract: In this work, the composite nanofibers of polybutylene terephthalate/polyethylene glycol (PEG/PBT) with difference intrinsic viscosity and different ratio of the hard-segment to the soft-segment were obtained by gas-electrospun. The PEG/PBT-HA composite nanofibers were also obtained by gas-electrospun. PEG/PBT and PEG/PBT-HA composite nanofibers were characterized using scanning electron microscopy (SEM), horizontal attenuated total reflectance for Fourier transformation infra-red spectrometer (HATR-FTIR), dynamic contact angle measurement and differential scanning calorimetry (DSC). The results strongly suggest that this synthetic matrix combines with the advantages of synthetic biodegradable polymers, nanometer-scale dimension mimicking the natural ECM, may represent an ideal tissue engineering scaffold, especially for soft tissue, such as skin and cartilage tissue engineering scaffold.

Abstract: Basing on the analysis of Mine Hoist working condition, Research on fault diagnosis system for Mine Hoist was introduced, including detailed introduction of its functions, composition and work principles. According to its application, it shows that fault diagnosis and monitoring technology to ensure that the equipment can run in good conditions so as to reduce unplanned downtime and help to reduce maintenance costs.

Abstract: Maintain the thermal stability of the machine tool is a common problem to achieve intelligent and precise processing control, and its difficulty lies in modeling and real-time compensation. In this paper, considering the correlation of various factors, the correlation of those factors according to experiment data was analysis and optimized, and a dynamic model of thermal error compensation of CNC machine tool based on Bayesian Network theory was found. Moreover, because of the self-learning feature of Bayesian network, the model can be continuously optimized by updating dynamic coefficient, and reflect the changes of processing condition. Finally, the feasibility and validation of this model were proved through the experiment.