Abstract: The novel phosphine was used with a silicon resin to impart flame resistancy to polycarbonate. Combustion behaviors and thermal degradation properties of flame retardancy PC have been assayed by limiting oxygen index, vertical burning test and thermogravimetric analysis. Dynamic rheological of FR-PC was also examined. Flame retardant consisted of 80 wt.% PPPO and 20 wt.% silicon resin possesses excellent flame retardancy for PC. LOI value of FR-PC is 33.0% and passes UL-94 V-0 rating. SEM revealed that the char yield as well as char properties have direct effects on the flame retardancy.
Abstract: The influence of microstructure evolution of a nickel-based superalloy after long-term aging on the tensile properties and deformation behavior was investigated. The results shows that the aging time exhibits an significant effect on the strength of alloy under low strain rate and the elongation decrease with increasing the aging time, but the aging time has no obvious effect on the strength of the alloy and elongation is affected significantly by aging time. During deformation under high strain rate, the dislocation motion is blocked and the dislocation can not release in time, the strengthening phase peak size effect does not appear in the aging time ranging from 0h to 1000h, so the influent of aging time on the strength of the alloy is not obvious. After long-term aging, no precipitation appear in both sides of the grain boundary which leads to the coordination ability of plastic deformation of grain boundaries reducing, so the ductility of the alloy decreases rapidly in a short aging time.
Abstract: Pure phase Fe doped BaTiO3 crystals have been successfully fabricated at 200°C with 0.7M KOH by a hydrothermal method. The obtained products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). An obvious morphology evolution from hexagonal shape to sphericity was observed when Fe doping concentration was increased from 0% to 1%, 3%, 6%, and 10%. In addition, the size of the obtained Fe doped BaTiO3 crystals obviously became smaller. The possible mechanism was also discussed.
Abstract: Effect of polaron on the spin triplet state (p-like) of the center is discussed by means of variational principle and second-order perturbation theory. Numerical results are produced for heterostructures of InP(GaP) in a magnetic field. We find that the polaron correction is very important. The contribution of the polaron is not negligible.
Abstract: The biodegradable nanocomposites of poly (3–hydroxybutyrate–co–3–hydroxyvalerate) (PHBV) with different cellulose nanocrystals (CNCs) contents were prepared by a solvent casting method. The effects of CNCs on the crystallization behavior of PHBV were studied by DSC. The DSC results showed that compared to PHBV, the melt crystallization temperature increased to 92.3 °C for the nanocomposites with 10 wt. % CNCs, which indicated that the crystallization of PHBV became easier with the addition of CNCs. Moreover, the non–isothermal crystallization kinetics study illustrated that overall crystallization rate of PHBV in the nanocomposites was faster than that of neat PHBV, which should be attributed to the strong heterogeneous nucleation of CNCs.
Abstract: A bismaleimide (BMI) resin system based on allyl condensed polynuclear aromatic resin and 4,4'-bismaleimidodiphenyl methane was prepared in this paper. The chemical structures and rheological properties of the resin prepolymer were characterized by FTIR and viscometer, respectively. DSC was used to study the curing reaction of the resin prepolymer, and TG-DTG was employed to study the thermal behaviors of the cured resin. Moreover, physical properties of the BMI resin, including mechanical and dielectric properties, were studied. The results showed that the BMI resin had good thermo-stability, good mechanical properties and excellent dielectric properties. Introduction
Abstract: The first principles calculation based density functional theory has been employed to investigate the changes of energy, bonds length and bonds angle of aryldiazonium salt Self-assembly monolayer (SAMs) on silicon (100) surface. The steady structure and binding energy can be determined. It is shown that the partial bonds length and bonds angle have been changed obviously before and after self-assembly. The reduced energy of system is-101.95eV, i.e. binding energy, which is emitted energy of Si-C covalent bond coming into being, illuminates that the SAMs can be fabricated easily between aryldiazonium salt and Si (100) surface. The stability of system can be improved and SAMs can firmly stay on Si (100) surface.
Abstract: Inverse spinel-type metal oxides, magnesium-manganese-titanium oxide(MgMn0.5Ti0.5O3), was prepared by a coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material was investigation by X-ray, saturation capacity of exchange, and Kd measurement. The acid treatments of MgMn0.5Ti0.5O3 caused Mg2+ extractions of more than 82%, while the dissolutions of Mn4+ and Ti4+ were less than 15%.The experimental results have proved that the acid-treated sample has a capacity of exchange 7.6 mmol•g-1 for Li+ in the solution.
Abstract: Ca1–3xLn2xTiO3 (Ln=La, Nd, Sm; x=0.13, 0.20) ceramics were investigated systematically to dicuss the influences of sintering temperature, compositions, Ln3+ ions on its sintering property, crystal structure and microstructure. The results show that the dense ceramics were obtained in the sintering temperature range of 1300~1350 °C and the relative density reached over 97%. Sintering temperature was 50~150 °C lower than previous reports. Single orthogonal perovskite structure phase was formed except that a little secondary phase Sm2Ti2O7 was detected by XRD analysis when x=0.20 and Ln=Sm. The growth pattern of Ca1–3xLn2xTiO3 grains was terracing growth.