Advanced Materials Research Vols. 798-799

Abstract: The polyurethane buffer is widely used in mechanical industry, intelligent manufacturing, internal combustion engine industry and etc.. The parameter design of the polyurethane buffer is often based on empirical formula with which it usually can not obtain the optimal parameter. This paper aims at studying the process of the buffer and optimizing its parameter. Firstly, the result of compression and shear tests of the polyurethane material is compared with simulation result to validate the simulation method is reasonable. Then buffers of different sizes with practical condition were simulated. During the simulation, this paper researched the maximum deceleration of the mass block in models with different sizes of polyurethane buffers. Lastly, the size of the buffer with minimum volume which is agreed with the request of the maximum deceleration of the mass block is obtained by data handling based on the simulation result, above on which a database was built.

Abstract: A series of composites of Polyaniline (PANI) and Polybenzobisoxazole (PBO) nanocomposites were prepared with different PANI compositions. The methanesulfonic acid (MSA) was used as dopant and solvent. The structures and morphology of the obtained nanocomposites were fully characterized by FT-IR, TGA, SEM and TEM. The effect of mass fractions of PANI, temperature and frequency on the dielectric property was studied. The PANI exhibited highly homogeneous dispersion in PBO matrix. The dielectric constants of the composites increased with PANI content and the testing temperature and decreased with frequency.

Abstract: By the means of Metallographic analysis, scanning electron microscope (SEM), and energy spectrum analysis, the development of SPA-H surface middle longitudinal crack was studied. To find out the causes of the longitudinal crack, statistical method was adopted. The result shows that, the generating process of longitudinal crack was: the changing of mould powder owing to Ti and Al element, low overheating degree, and bad slag smelting, which leading to bad transfer heat of slab and depression. For the thermal stress of solidifying contraction, molten steel static pressure, and mould friction, the stress concentration was produced in the weak place of solidified shell, for example, in the small equiaxial crystal less than 1mm. the cracking occurred when the stress more than allow strength of high temperature slab.

Abstract: In this article, epoxy-based dielectric materials for solid insulator were investigated. First, epoxy-based polymeric samples with different permittivities were prepared by incorporating a mixture of two fillers (Al₂O₃ and SrTiO₃) into epoxy matrix. Then, dielectric properties were characterized for the epoxy-based samples by using a dielectric spectrometer with varied frequency. Finally, breakdown tests were performed under AC voltage to characterize the breakdown strength of the dielectric material. Results indicated that the permittivity (dielectric constant) of epoxy-based materials can be adjusted only by changing the mixing ratio of two types of fillers. On the other hand, the obtained dielectric materials showed acceptable breakdown strength with the present amounts of fillers.

Abstract: Taking 7 group anthracite coal samples which size is 1¡«3mm from different coal mines of the same mine field as research objects, there carried coal samples' methane adsorption and desorption experiment under the condition of about 1Mpa¡¢2Mpa¡¢3Mpa¡¢4Mpa adsorption equilibrium pressures and adsorption equilibrium temperature 20¡æ. The coal samples' cumulative methane desorption volume of each minute were measured in the initial 30 minutes time, and there obtained the desorption data. Based on experimental data analysis found that the methane desorption law between cumulative methane desorption volume and desorption time is fit to SUN Chong-xu Formulate (Q=atⁱ). Then aimed to the same coal sample, the desorption eigenvalues of different adsorption equilibrium pressures were studied using SUN Chong-xu Formulate based on the experiment data. The study results show that the coal sample's desorption eigenvalues of different adsorption equilibrium pressures keeps a constant, and the average eigenvalues is 0.237 for these experiment samples. Then 1~3mm size coal samples can be used to determent methane content when the loss time less than 8 minutes.

Abstract: Large pore SBA-15 microspheres were synthesized by a simple mesitylene (TMB)-assisted method. A series of characterization results demonstrated that the addition of mesitylene can not only obtain large-pore particles by forming siliceous mesocelluar foam (MCF) structure but facilitate the formation of spherical SBA-15 silicas. It was found that, by the addition of certain amount of TMB, the morphology of SBA-15 silicas is perfectly spherical while the pore structure remains unchanged. And the well-ordered SBA-15 microspheres exhibit large pore and good dispersibility.

Abstract: Na-montmorillonite was modified by ionic liquids as the intercalation agent with different side chains. The influence of side chains in ionic liquid to Na-montmorillonite after intercalation was discussed. The chemical structures of ionic liquid/organic montmorillonite complexes were characterized. The results indicated that the ion-exchanging reaction can be happened in ionic liquids and montmorillonite, which the space increased between of organic modified montmorillonite, and the longer chain of ionic liquid, the greater distance of montmorillonte.

Abstract: In this article, the potassium permanganate solutions (KMnO₄) was used to treat the PPTA fiber based on an orthogonal experimental design. The optimum conditions of KMnO₄ treatment were concentration of 20%, temperature of 30°C and treating time of 20min. The interfacial properties of aramid fiber/epoxy composites were investigated by the single fiber pull-out test (SFP), and the results showed that the interfacial shear strength (IFSS) of aramid/epoxy composites was remarkbly improved.

Abstract: A series of iridium (III) complexes (C^N)₂Ir (Pic) (C^N = Phi (1), Ppi (2), Mpfpi (3), and Cpfpi (4) have been investigated theoretically to explore their electronic structures and spectroscopic properties. The calculate bond lengths of Ir-N and Ir-O in the ground state agree well with the corresponding experimental results. At the TD-DFT and PCM levels, 1-4 give rise to absorptions at 359, 360, 348, and 335 nm and phosphorescent emissions at 454 , 469, 441, and 425 nm, respectively. The transitions of 1-4 are all attributed to {[d (Ir)+π (C^N)][π*(C^N) or π*(Pic)]} charge transfer. It is shown that the emissions are significantly dominated by the metal participating in the frontier molecular orbitals and affected by the C^N ligands.

Abstract: Synthetic method of gold nanoparticles was introduced and matters needing attention in the experiment were also emphasized in this paper. Gold nanoparticles with high concentration were prepared by centrifugation. Use transmission electron microscope to characterize the particles size of the gold nanoparticles.