Advanced Materials Research Vols. 148-149

Abstract: In this paper, the perfluoro aryl ether dendrons were synthesized by mesylate reaction, and using the dendron as a modifier to prepare a novel fluorinated polyhedral oligomeric silsesquioxane ( F-POSS) nano-particle bearing this fluorine-containing dendron. In this approach, the Williamson ether synthesis technique was used as the generation enhancement step. Second generation perfluorobenzyl alcohol dendron was obtained from active mesylated precursors. This mesylate actiation technology has the advantage of short reaction times in the subsequent steps and avoids chromatographic purifiction. Second genenriation dendron was then built by repitition of Williamson ether synthesis reaction of mesylate derivative. It is possible for this new nano-particle to be used in the modification of polymer materials to make the durable superhydrophobic and oilphobic surface functional materials with excellent self-cleaning properties.

Abstract: In engineering technology, it is necessary to compare different designs in an optimization project. Therefore a big problem is how to obtain finite element analysis (FEA) data involving different parameters and how to acquire optimization parameters from the results of FEA to solve the optimization problem rapidly. The parametric mesh (Paramesh) method, automatically based on history of complicated special surfaces, is developed to obtain many results of FEA involving different parameters. This paper is presented to demonstrate the method of parametric finite element analysis (PFEA). The optimization method of process parameters optimization is based on combining PFEA/ ANN (artificial nerve net)/GA (genetic arithmetic) to find out optimization parameters. This allows one to rapidly obtain optimization parameters during a design by doing FEA only once. The research indicates that the parameters optimization method based on PFEA/ANN/GA in the product design can short the product development cycle, decrease material consumption and guarantee product quality, etc.

Abstract: Hysteresis loop and dielectric properties of lead-free BaTiO3-La2O3 piezoelectric ceramics and BaTiO3 ceramic compared with pure BaTiO3 has been systematically studied. The amount of La2O3 addition ranged from 0.3~0.5mol% by controlling the sintering temperature. Dielectric properties of BaTiO3-La2O3 were promoted after the addition of La2O3, the maximum value of dielectric constant reached 8,624, recently. The role of La2O3 on the solid-state sintering of BaTiO3 is discussed on the basis of the solid-solution defect model.

Abstract: In this study, we have presented a smart core/shell nanocomposite: intelligent polymer modified iron nanoparticles (PNZVI), which can be easily synthesized by the microemulsion method followed by a in-situ surface-radical graft polymerization. The structure and composition of the nanocomposite particles prepared were characterized by transmission electron microscope (TEM), X-ray diffractometer (XRD), Fourier transfer infrared spectrometer (FTIR) and thermal analysis (TG). The PNZVI exhibited good stability in air since the coating of polymer effectively protected the iron core from oxidation. Furthermore, the stimuli-response of outer polymer layer was capable of creating a stable dispersion of nanoparticles and improving the compatibility of the composite particles with organic pollutant. Batch experiments further confirmed that the prepared PNZVI were capable of effectively reducing trichloroethylene (TCE).

Abstract: Activated carbons (ACs) were prepared by microwave−assisted heating of bituminous coal with KOH as activation agent in different gas media for supercapacitors. The pore structure parameters of ACs are obtained by using nitrogen adsorption technique. ACs prepared in static nitrogen, flowing nitrogen and carbon dioxide are denoted as ACStatic-N2, ACFlowing-N2, ACFlowing-CO2. The specific surface area of ACFlowing-N2 is the biggest among the three ACs, which reaches 1201 m2g-1 with total pore volume being at 0.64 cm3 g-1. The specific capacitance of ACFlowing-N2 electrode and energy density of ACFlowing-N2 capacitor is the biggest among the three AC samples with specific capacitance being at 302.6 F g-1 and energy density being at 10.1 Wh kg-1 after 400 cycles. The microwave−assisted KOH activation of coal is an efficient approach to the preparation of ACs for supercapacitors.

Abstract: In this paper, a low phase noise hybrid integrated voltage-controlled oscillator (VCO) module with harmonic suppression based on LTCC technology is presented. This is the first report about the hybrid integrated VCO module based on the LTCC substrate in china mainland. The design is simulated and optimized by the ansoft designer and the ansoft HFSS software. To miniaturize the VCO module, two capacitors and an inductor that adjust the oscillation frequency and two capacitors as feedback capacitors are buried in the LTCC substrate. Three resistances for direct current bias are made on the surface of the LTCC substrate. Also the low-pass filter that used for harmonic suppression is embedded in the LTCC substrate. The VCO module achieves an output power of more than 10 dBm in a tuning range between 1000-1200MHz. The measured phase noise is lower than -112.2 dBc/Hz at 10KHz offset between 1000-1200MHz. The overall dimension is as small as 8 mm×7 mm×3.5 mm.

Abstract: Weld bead stability has an important effect on the quality of prototyped products .In the paper, hierarchy analytical theory, combined with the experiment, is employed to determine the weld bead stability synthesis evaluation weight coefficient of surface quality, weld reinforcement and weld width of weld bead. The membership degree tables of surface quality, weld reinforcement and weld width are created by using fuzzy theory. Thus a evaluation method of bead stability is established and applied to evaluate practical bead stability. It is approved that the calculation value accords with the actual result, which proves the evaluation method of bead stability is effective.

Abstract: The bascule bridge is one of the most suitable bridge types for ports and rivers in cities. In order to discuss the mechanical behavior of the pavements in the opening process, the finite element model of the pavement system on the Haihe Bridge being built in Tianjin China was built, and the mechanical response in the opening process was calculated. The research results show that the asphalt paving with the thickness of 30mm~40mm is fit for the bascule bridge. The max shear stresses of pavement between pavement and steel plate in the opening process rise with the increase of Young’s modulus, and the high temperature during the construction and conservation after construction should be provided.

Abstract: Spinel LiCoxMn2-xO4 powders were prepared by sol-gel combined with heating treatment process. The structure, morphology and electrochemical properties of LiCoxMn2-xO4 powders were characterized by XRD, TEM and constant current charge/discharge techniques. The results show that lattice constant and crystal size of LiCoxMn2-xO4 powder decrease and the crystal aberrance increase with the increasing of cobalt content which has less effect on its spinel structure. The initial discharge special capacity of LiCoxMn2-xO4 decreases slightly with the increasing content of Co but its cyclic performance is improved obviously resulted from the improvement of structure stability. Comprehensively the special capacity and the cycle performance, LiCo0.1Mn1.9O4 composed of about 80nm particles exhibits superior electrochemical property and may be used as the cathode material in new type Li-ion battery.

Abstract: The sol-gel method was used to prepare three kinds of nanometer magnetic particles, the nano-cobalt ferrite oxide powders and those doped by LaCl3.nH2O with different ratio. In the thermo-decomposition process of the precursors to get these magnetic particles, TG/DTG was applied for investigating their character. It has been showed that the difference of the activation energies of these particles in different thermo-decomposition stage, even not in the same stage for different sample. XRD was used to analysis the effect of temperature on precursor of CoFe2O4. It has been showed that the prepared magnetic particles with the average diameter less than 100nm were characterized by XRD and TEM. To study nano-magnetic particles and polymer electrolyte compounds, the three kinds of nanometer magnetic particles were doped into polyethylene glycol-20000 (peg-20000) with different rations respectively to obtain the compound substance with optimal conductivity, 0.686 S.m-1.