Development of C-Dots-based fluorescent materials with multicolor emissions in the solid state is critical in photoelectric imaging and lighting, yet it is still a challenge to obtain such material with...

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It is profound to obtain simply carbon nanodots (CDots)-based solid-state fluorescent in photoelectric field. However, synthesizing such material is still faced with a challenge due to the serious quenching effect. Here, a microwave pyrolytic route is reported to rapidly synthesize sulfur (S) and nitrogen (N) co-doping CDots wrapped by the crystalline phthalate (CDots/PA). The results show that CDots/PA presents needle-like crystal to coat abundant cluster of CDots inside, after fully optimizing the preparation conditions. The solid state CDots/PA emits a dazzling fluorescence with the fluorescence quantum yield (FLQY) [Formula: see text]%, which is attributed to the formation of barrier from the crystal to avoid the aggregation of CDots. In addition, due to the co-doping of S and N elements, it also presents an orange–red light with a multipeak feature. The excellent photoluminescence (PL) property of CDots/PA gives it an advantage to fabricate light emitting diode (LED)/white light emitting diode (WLED) devices, which achieves an orange light with the correlated color temperature [Formula: see text][Formula: see text]K, color rendering index [Formula: see text] and a warm-white light with the CCT [Formula: see text] 3700[Formula: see text]K, CRI [Formula: see text] 82 at the Commission Internationale de L’Eclairage [Formula: see text], 0.40) combined with the commercial phosphors. Moreover, CDots/PA also shows an excellent recognition capacity in the application of detecting latent fingerprints, endowing such fluorescent nanomaterials broad prospect in the photoelectric industry.

The composite strata of coal floor is an important barrier to block the lifting and bursting of thick limestone groundwater into the mining space. Taking J3 and J4 mining areas of Handicapping Coalfield as the object, this paper selected the thickness ratio of plastic brittle rock core recovery rate, composite comprehensive strength, Equivalent water barrier coefficient, Effective water-resistant layer thickness and fault complexity as the main control factors, and determined the comprehensive weight of index factors based on the entropy weight theory. Using the Archaist vulnerability index grading evaluation model, the water-isolation ability of the composite strata in the floor of J 16-17 coal seam is quantitatively evaluated and divided into five grades: extremely weak, weak, medium, strong and extremely strong. The results show that the areas with strong and extremely strong water-isolation ability of the composite strata of coal floor account for 38.67% of the total area, the areas with moderate and extremely weak water-isolation ability account for 51.45%, and the areas with weak and extremely weak water-isolation ability account for 9.88%. In this paper, the coupling effect of multiple factors on composite strata is considered, and the quantitative classification and zoning discrimination of water-isolation ability of composite strata is realized, which provides technical support for accurate evaluation of water-inrush risk of coal floor.

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