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Silver nanoclusters confined zeolite scaffolds have been considered as a promising luminescent material. Herein, luminescent silver nanoclusters were synthesized by incorporating Ag+ and Cs+ ions into the as-synthesized SOD zeolites...

Luminescent silver nanocluster zeolite composites have aroused intensive attention of the research community because of their outstanding optical performances. Herein we report one such luminescent nanocomposite by assembling silver nanoclusters within the analcime (ANA) zeolite by sonicating the silver-exchanged ANA zeolites in the presence of an appropriate amount of terephthalic acid (TPA). The addition of TPA can prevent the formation of larger nonluminescent silver nanoparticles (Ag NPs), increase the photoluminescence quantum yield, and adjust the emission color of the resulting luminescent composites, varying from orange to yellow to white via changes in the TPA concentration. It is believed that the TPA molecules added during the synthesis process favor the dissolution of large nonluminous Ag NPs formed on the surface of the zeolite, leading to a significant decrease in both the number and size of the Ag NPs. In addition, a warm-white light-emitting device was fabricated by integrating the composites on a near-ultraviolet 365 nm chip. Our method might demonstrate a perspective for the rational synthesis of luminescent silver nanoclusters.

A series of Ag-zeolite luminescent composites are prepared based on SOD and FAUY zeolites, and the effect of zeolite host particle size on their dynamic luminescent emission properties was discussed for the first time. The relationship between zeolite particle size and the nucleation of silver nanoclusters (AgNCs) is revealed. With the increase of zeolite particle size from nanometers to microns, the luminescent color of both Ag-SOD and Ag-Y composites shows significant blue shift. The observed tunable luminescence can be accounted for the slower nucleation rate of AgNCs in micron-scale zeolites with longer channels, resulting in smaller nuclearity of AgNCs within large-size zeolites, through the characterization of extended X-ray absorption fine structure, implying the important roles played by the zeolite themselves in determining the luminescence properties. Moreover, the composites prepared by us feature simple signal transduction, fast response (30 s), and excellent selectivity and sensitivity for discriminative luminescence detection of triethylamine and ethylamine, and they have good reversible luminescence response after sensing HAc gas, which might imply the potential applications in the volatile organic amine detection and information encryption field.

Understanding the interactive coupling mechanism between urbanization and eco-environmental quality is crucial to achieve the goal of urban sustainable development. The Chinese Loess Plateau (CLP) was taken as the research object, and the city nighttime light index (CNLI) and remote sensing ecological index with local adaptability (LARSEI) were constructed based on the data from the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS), National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (NPP/VIIRS), and Moderate Resolution Imaging Spectroradiometer (MODIS). Then, trend analysis, standard deviation ellipse (SDE), coupling degree (C), and coupling coordination degree (CCD) models were used to determine the spatiotemporal variation of urbanization and eco-environmental quality and its coupling relationship. The results show that: (1) the urbanization level of the CLP showed a trend of continuous improvement from 2000 to 2019. A significant increasing trend was found from the CNLI (slopeCNLI = 0.0030 yr−1, p < 0.01), and its value rose from 0.07 in 2000 to 0.14 in 2019. In terms of spatial distribution, a multi-core distribution pattern with provincial capital cities as the core was presented in the CLP. The cities expanded at different degrees and presented a gradual concentrated expansion towards the southeast on the whole. (2) The eco-environmental quality in the CLP greatly increased during 2000 to 2019. An area with an increasing trend in the remote sensing ecological index with local adaptability (LARSEI) accounted for 58.82% and was mainly concentrated in the west and central part of the CLP. (3) The C and CCD between urbanization and eco-environmental quality in the CLP presented a trend of significant increase during 2000 to 2019 (slopeC = 0.0051 yr−1, p < 0.01; slopeCCD = 0.0040 yr−1, p < 0.01). The cities with a higher coupling degree were mainly located in the southeastern and northern parts of the CLP, while those with a higher coordination degree were scattered in the marginal parts of the CLP. The research results can provide suggestions for decision-making to achieve high-quality coordinated development of the cities in the CLP.

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This paper studies an approach of nonlinear independence test between random variables. The method is Hilbert–Schmidt independence criterion (HSIC), one of the popular kernel methods for testing statistical dependence between random variables. There are several advantages of using HSIC method. It is easier compared with other kernel methods like the canonical correlation, because it requires no extra regularization terms for an appropriate finite sample behavior. Also, the learning rates of HSIC method is faster because there exists a well-defined population quantity in the estimate. The paper studies the detailed concepts and criterion associated with HSIC, its p-value and sensitivity maps. Results in the experiment about the wine data from UCI data set show the good performance of the approach.

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