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Europium doped borosilicate glasses were prepared in CO reducing atmosphere. The glasses were systematically investigated through XPS, photoluminescence (PL), fluorescence decay curves and X-ray excited luminescence (XEL). XPS results show that the glasses contain Eu2+ and Eu3+ at the same time. Under the excitation of 360 nm light, only a broad blue emission with peak around 440 nm due to the 5d→4f transition of Eu2+ is observed, while the emissions from Eu3+ do not appear in the PL spectra. The fluorescence decay curves were monitored at 440 nm, and the measured lifetimes are in the range of 0.17–0.42 μs. The PL results indicate that the PL emission from Eu2+ is significantly intense than the PL emissions from Eu3+. Upon X-ray excitation, two main emissions with peaks at 445 nm and 616 nm corresponding to Eu2+ and Eu3+ are obtained. The XEL results reveal that the XEL emissions from Eu3+ are comparably intense as the XEL emission from Eu2+. The results indicate that europium doped borosilicate glass could be a potential scintillating material in X-ray detection filed.

Eu3+ doped tellurite scintillating glasses were prepared by the conventional melt-quenching method. The physical and luminescent properties of glasses were investigated by DTA, density, transmittance spectra, photoluminescence spectra, and X-ray excited luminescence (XEL) spectra. The densities of the glasses are in the range from 5.89 g/cm3 to 6.05 g/cm3. The glasses exhibit intense red emissions upon 393 nm light and X-ray excitations. The maximum integral XEL intensity of the glasses is about 6% of that of commercial Bi4Ge3O12 (BGO) scintillating crystal. The results reveal that Eu3+ doped tellurite glass could be a scintillator candidate used in X-ray detection field.

International audience; Lanthanide-doped up-conversion (UC) materials with color tunable property show promising application in many fields, such as biological imaging, optical multiplexing, and information security. Although great efforts have been devoted to regulate UC emission color via modifying chemical composition, crystal structure, or external stimuli condition, it is remain a daunting challenge to develop a general strategy that probably suitable for various lanthanide-doped nano-systems. Herein, we verify the cross-relaxation possibility between sensitizer Yb3+ and activator Er3+ as well as Er3+- Er3+ pairs can be well modified by engineering the crystal lattice distortion of matrix, leading to the evident UC emission color variations. Specifically, with incorporating Al3+ or Ca2+ ions into the Yb/Er co-doped BaF2 nanocrystals (NCs) contained glass ceramics (GCs), the contraction of the crystal lattice lead to the change of UC emission color from green to red. On the contrary, the high laser excitation power results in the lattice expansion of the Al3+-doped BaF2:Yb/Er GCs at different Yb3+ concentration as well as Al3+ doped CaF2 GCs, which leads to the greatly increased green-to-red ratio. These multi-color UC GCs show potential application in anti-counterfeiting filed. Our results open up a general avenue for the control of UC emission color via engineering crystal lattice distortion.

Changes in marine export productivity may have played a prominent role in the atmospheric CO2 rise and associated warming of the last deglaciation, via their impact on the air-sea partitioning of CO2. To study the evolution of marine export production in the western subtropical Pacific Ocean during the last deglaciation and the mechanisms governing these changes, 230Th-normalization has been applied on a sediment core retrieved from the Okinawa Trough. The reconstructed export productivity record shows two prominent peaks, centered around 14 and 17 ka. Given that phytoplankton growth at our study site is limited by the availability of nutrients today, elevated macro-nutrient supply must have been responsible for sustaining the two deglacial productivity peaks. Specifically, higher nutrient supply originating from the subpolar gyre via subsurface water advection, with enhanced vertical mixing in the subpolar gyre during early HS1 and enhanced wind-driven upwelling during the B/A, would have fueled phytoplankton productivity and export. In contrast, reduced nutrient supply to the euphotic zone caused by gyre circulation changes would have lead to decreased export production during the Holocene. These observations lend support to a predominant control of nutrient availability on the evolution of the marine carbon cycle in the subtropical west Pacific Ocean across the last deglaciation.

In the grounding system of the neutral point through the arc suppression coil, due to the compensation effect of the arc suppression coil (ASC) on the ground point fault current, the zero sequence current (ZSC) characteristic of the fault line is not obvious, which seriously affects the accuracy of single-phase ground fault line selection. Therefore, based on the analysis of the feasibility of adjusting the turn-adjusting arc suppression coil in the case of a single-phase ground fault, this paper proposes a new small-distance method to select the line technology for the turn-adjusting arc suppression coil. The results show that the method is highly reliable and practical, and can effectively improve the accuracy of line selection.

The application of the Internet of Things technology to agricultural electrification production, especially agricultural greenhouse cultivation, can greatly improve the quality of agricultural products. This article summarizes the application technology of the Internet of Things technology in five aspects of agricultural greenhouse insulation, electric rolling shutters, electric drainage and irrigation, electric supplementary light and electric ventilation. Deep integration with agricultural production to improve agricultural planting benefits.