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Yb 3+ and Er 3+ /Tm 3+ co-doped NaLuF 4 upconversion nanoparticles (UCNPs) with strong visible luminescence under the excitation of infrared light are successfully synthesized. The synthesized NaLuF 4 upconversion nanorystals have acidic ligand and can quickly capture the basic dyes to form UCNPs@dye nanosystem, in which the efficient luminescence resonance energy transfer (LRET) can be observed from UCNPs to dyes. We select NaLuF 4 :Yb 3+ /Er 3+ UCNPs as a model to detect Rhodamine B (RB) in plant cells. NaLuF 4 :Yb 3+ /Er 3+ UCNPs can emit green light at the wavelength of ∼545 nm while RB can efficiently absorb the green light of ∼545 nm to emit red light of 610 nm. As a result, the LRET process can occur in NaLuF 4 :Yb 3+ /Er 3+ @RB system. Based on the LRET process, an excitation power limit of 60 μW can be achieved in detecting traces of RB in plant cells. This LRET process is also used for detecting sodium fluorescein with the excitation power limit of 65 μW. [ABSTRACT FROM AUTHOR]

Here, we show the simultaneous enhancement of fluorescent and paramagnetic properties in bifunctional NaGdF 4 :Yb 3+ /Er 3+ nanocrystals by crystal field tuning. The energy level splitting calculation indicates, that lanthanide ionic pairs La 3+ /Lu 3+ introduced into the NaGdF 4 host can modify the crystal field around emitters (e.g., Er 3+ and Tm 3+ ) and sensitizers (e.g., Yb 3+ ) that result in the broadening of crystal field splitting of energy levels and the abundant multi-site distribution of upconversion luminescence. The optimization of the paramagnetic properties in NaGdF 4 doped with emitters and sensitizers is ascribed to the lowering of anti-ferromagnetic coupling. [ABSTRACT FROM AUTHOR]

It is challenging for current compressive sensing (CS) approaches to reconstruct image from compressed observations with impulsive noise and outliers, termed robust image CS problem. In this paper, we propose a novel reconstruction model for the robust image CS reconstruction problem in the presence of impulsive noise. To ensure high-quality image reconstruction, we develop a nonlocal low-rank plus deep denoising prior model to simultaneously capture the nonlocal self-similarity (NSS) and deep prior, leading to a complementary reconstruction effect. Moreover, the robust M-estimator is utilized to suppress the outliers, which can strongly improve the robustness to impulsive noise. Considering the nonconvexity and complexity, both the half-quadratic (HQ) strategy and the alternating minimization method are employed to minimize the resulting large-scale optimization problem. Extensive experiments have demonstrated the effectiveness and superiority of our method significantly than the existing state-of-the art CS methods in terms of both visual quality and quantitative indexes under impulsive noise. • A robust image CS reconstruction approach with nonlocal low-rank plus deep denoising prior is proposed. • An efficient optimization framework based on half-quadratic (HQ) theory and the alternative minimizing scheme is developed. • The superior reconstruction performance is confirmed over various advanced CS algorithms. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Detecting the content of water in organic materials by using Au/UCNPs. • Detecting the content of ethanol in liquor. • Using FDTD to simulate and analyze the experiment. • Experiment results are well consistent with simulation. Abstract Here, we demonstrate the well linear dependence of the fluorescent intensity of upconversion nanoparticles (UCNPs) on the concentration of ethanol at the concentration range of 25%–90% (typical ethanol concentration in Chinese liquors) by employing surface plasmon resonance (SPR) to stabilize the upconversion processes. UCNPs are successfully synthesized by a solvothermal method which emit green light centered at 540 nm under the excitation of 980 nm infrared light. We select Au nanorods with the absorption peaks centered at 525 nm and 928 nm (a wide band covered the wavelength region of 980 nm) for tuning the upconversion luminescence process of UCNPs so that the fluorescence intensity is linearly dependent on the content of ethanol from 25% to 90%. The Au/NaGdF 4 :Yb3+, Er3+ hybrid fluorescent system may be an ideal strategy for rapidly detecting the content of ethanol in liquor and discerning the adulterated liquor. [ABSTRACT FROM AUTHOR]

Abstract: A new susceptor with a partial-torus groove in the vertical metal organic vapor deposition (MOCVD) reactor by induction heating is presented. By using the finite element method (FEM), it is found that this groove changes the mode of the heat transfer in the susceptor. That is to say, the single mode of the heat conduction in the conventional susceptor is changed to the modes combining the heat conduction and the radiation. By optimizing this susceptor for heating 8-inch substrate, it is observed that compared with the conventional susceptor, the uniformity of the temperature distribution is improved more than 83%. The uniformity of the temperature distribution in the substrate is significantly improved, which will be of benefit to the film growth. [Copyright &y& Elsevier]