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Hundreds of high-quality 25 mm $\times $ 25 mm $\times \,\, 600$ mm Bi4Ge3O12 single crystals were industrially grown by the Bridgman method for the DArk Matter Particle Explorer (DAMPE) project. With respect to the crystals with the best optical quality, the optical transmittance along the longitudinal and transversal directions can achieve 72% and 76% at 480 nm, respectively. Most of the grown crystals satisfied the light output uniformity requirement of the DAMPE calorimeter. For the remaining crystals, the effects of air annealing, reflector materials, and surface treatment on the improvement of light response uniformity were also studied. [ABSTRACT FROM AUTHOR]

Abstract: Pure Li6Gd(BO3)3 single crystals with maximum dimension up to 23mm in diameter and 180mm in length have been grown successfully for the first time by the modified Bridgman method in platinum crucibles in the air atmosphere. The phase was checked by X-ray powder diffraction (XRD) and the symmetry belongs to monoclinic system with P21/c space group. The analysis of main compositions indicates a depletion of Gd and an excessiveness of Li or B in the tail of as-grown crystals ingots. It was found that the as-grown crystal has high optical transmittance within wavelength concerned. Photoluminescence (PL) and X-ray stimulated luminescence (XSL) of the as-grown LGBO crystals at room temperature were measured and discussed. [Copyright &y& Elsevier]

Nitrite, an intermediate product of the oxidation of ammonia to nitrate (nitrification), accumulates in upper oceans, forming the primary nitrite maximum (PNM). Nitrite concentrations in the PNM are relatively low in the western North Pacific subtropical gyre (wNPSG), where eddies are frequent and intense. To explain these low nitrite concentrations, we investigated nitrification in cyclonic eddies in the wNPSG. We detected relatively low half-saturation constants (i.e., high substrate affinities) for ammonia and nitrite oxidation at 150 to 200 meter water depth. Eddy-induced displacement of high-affinity nitrifiers and increased substrate supply enhanced ammonia and nitrite oxidation, depleting ambient substrate concentrations in the euphotic zone. Nitrite oxidation is more strongly enhanced by the cyclonic eddies than ammonia oxidation, reducing concentrations and accelerating the turnover of nitrite in the PNM. These findings demonstrate a spatial decoupling of the two steps of nitrification in response to mesoscale processes and provide insights into physical-ecological controls on the PNM.