Papers by Author: Tao Li

Abstract: Based on the braking system of a tracked vehicle, a method for co-simulation is introduced with dynamic simulation software ADAMS and multidisciplinary dynamic simulation software EASY5. By designing software interface, dynamic data exchange between the two models is achieved, and the simulation is carried out about the impact on a tracked vehicle brake performance with accumulator volume and gas-filled pressure. The simulation result shows that a seamless connection between the virtual prototype model and hydraulic system model is realized.

Abstract: This paper proposed a 4-weighted fractional Fourier transform (4-WFRFT) based carrier modulation technique. The system performance applying such modulation is analyzed under burst interference, and then compared with single carrier (SC) modulation and multi carrier (MC) modulation based systems. Simulation results show that 4-WFRFT system achieves a better performance than those of SC and MC systems since the 4-WFRFT has the capability to disperse the energy of interference signals in fractional Fourier transform domain. When the SIR of burst interference is -2dB, there is no error floor occurs in 4-WFRFT system, while the error floor appears in both SC and MC systems.

Abstract: Dynamic mechanical analysis (DMA) tests are conducted on styrene-based shape memory polymer(SMP) to investigate its glass transition behaviors. The tensile tests at various temperatures are operated to detect the stress-strain relationship of styrene-based SMP. The material elastic moduli and yielding limits at 25oC, 30oC, 40oC, and 50oC are determined according to the results of tensile test. A new material parameter function is supposed to express the glass transition behavior of styrene-based SMP. The shape memory thermo-mechanical cycle of styrene-based SMP is numerically simulated by Tobushi’s constitutive equation coupled with the new material parameter function. Numerical results show the new material parameter function can express the thermo-mechanical properties of styrene-based SMP effectively.

Abstract: Optical spectroscopic properties of Er3+-doped alkaline-earth metal modified fluoropho sphate glasses have been investigated experimentally for developing broadband fiber and planar amplifiers. The results show a strong correlation between the alkaline-earth metal content and the spectroscopic parameters such as absorption and emission cross sections, full widths at half-maximum and Judd-Ofelt intensity parameters. It is found that strontium ions could have more influences on the Judd-Ofelt intensity parameters and the absorption and emission cross sections than other alkaline-earth metal ions such as Mg2+, Ca2+, Ba2+. The sample containing 23 mol% strontium fluoride exhibits the maximum emission cross section of 7.58 × 10-21 cm2, the broadest full width at half-maximum of 65 nm and the longer lifetime of 8.6 ms among the alkaline-earth metal modified fluorophosphates glasses studied. The Judd-Ofelt intensity parameter W6s, the emission cross sections and the full widths at half-maximum in the Er3+-doped fluorophosphate glasses studied are larger than in the silicate and phosphate glasses.

Abstract: Electrochemical impedance spectroscopy (EIS) tests of anisotropic Nd-Fe-B magnets prepared by spark plasma sintering (SPS) technique were carried out to investigate their corrosion kinetics in different solutions. According to the Nyquist and Bode diagrams, convenient equivalent circuit was modeled and the values of the proposed equivalent circuit components were calculated. It was found from the EIS plot formats that the electrochemical reaction of SPS Nd-Fe-B magnets was controlled by the step of surface charge transfer i.e. activation polarization in alkaline solution, while controlled by step of active substances adsorption on the magnet surface in salt and acidic solutions. Compared with conventional sintered Nd-Fe-B magnets, the SPS Nd-Fe-B magnets possess better chemical stability in saline and weak acidic environment.