Xiaohui Qi

Novel Y2(MoO4)3:Eu3+ red phosphors were synthesized through a simple coprecipitation process and characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and fluorescent spectrophotometry. The results of XRD and FE-SEM show that resultant samples are single phase and have flowerlike shape. In the excitation spectra of Y2(MoO4)3:Eu3+ phosphors, by monitoring 616 nm, the charge transfer bands (CTB) of Eu3+→O2- and Mo6+→O2- centering at around 264 and 310 nm can be observed, respectively. Moreover, the intensity ratio of charge transfer band between Eu3+→O2- and Mo6+→O2- increases with increasing Eu3+ ions doping concentration. The characteristic red emission at around 616 nm of Eu3+ ions is also observed, ascribed to the 5D0→7F2 transition of Eu3+ ions, and the optimal doping concentration is 12 mol %. Finally, the Ωλ (λ = 2 and 4) intensity parameters and Huang−Rhys factor were also calculated according to Judd−Ofelt theory and multiphonon relaxation theory, respectively.

Active disturbance rejection control (ADRC) was originally given in a nonlinear gain structure to better accommodate the dynamic uncertainties and disturbances. However, the resulting complexity in a theoretical analysis and in the parameter tuning inhibits the applications of an ADRC. ADRC was linearized and parameterized for a practical convenience. Since linear ADRC (LADRC) and nonlinear ADRC (NLADRC) each has its own advantages and disadvantages, choosing between LADRC and NLADRC is rather difficult. As a matter of fact, there is a lack of quantitative analysis and comparison between LADRC and NLADRC. This paper first gives an easy solution in the parameter tuning of the nonlinear extended state observer, followed by a quantitative analysis and comparison study on LADRC and NLADRC; then, an LADRC/NLADRC switching control (SADRC) scheme is proposed and its stability is analyzed; finally, the SADRC scheme is verified by experiment using the ball-beam platform. The proposed SADRC takes the advantage of the additional performance improvement associated with the NLADRC, but make it easier to use.

nanoparticle/polystyrene hybrid fibrous membrane (HFM) was fabricated using an electrospinning technique. The HFM shows upconversion luminescence (UCL), flexibility, superhydrophobicity and processability. The UCL membrane can be used as a fluorescence sensor to detect bioinformation from a single water droplet (~10 μl). Based on the fluorescence resonance energy transfer, the detection limits of this sensor can reach 1 and 10 ppb for the biomolecule, avidin, and the dye molecule, Rhodamine B, respectively, which are superior to most of the fluorescence sensors reported in previous works. After the fluorescence detection, the target droplet was easily removed without residues on the UCL membrane surface due to its superhydrophobic property, which exhibits an excellent recyclability that cannot be achieved by traditional liquid-based detection systems.