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In this study, Ho3+/Yb3+ co-doped near-infrared fluorosilicate glass was melting with different concentrations of rare earth ions using a high-temperature melting method. Under 980 nmLD excitation, the Ho3+/Yb3+ co-doped fluorosilicate glass emits a near-infrared radiation of about 2.0 μm. The upconversion fluorescence spectrum reveals weak green light and strong red light. Next, the energy transfer mechanism and spectral characteristics of near-infrared radiation were examined. Fluorosilicate glass has favorable conditions such as relatively low cost, high light transmittance, and good thermal stability. Ho3+ the emission cross-section and gain coefficient were calculated to be 0.51 × 10–20 cm2 and 0.903 cm−1, respectively. Furthermore, given the Judd–Ofelt theory, calculated and analyzed the Ho3+/Yb3+ co-doped Ωt (t = 2, 4, 6) of 4.25, 2.45, and 0.8, respectively, indicating that the stimulated emission of Ho3+ was strong. The sample’s maximum fluorescence lifetime at 2.0 μm was 0.856 ms, which was 0.182 ms longer than that of silicate glass. This indicates that the addition of fluoride is beneficial to improve the fluorescence lifetime at 2 μm. According to the testing results, Ho3+/Yb3+ co-doped fluorinated silicate glass has a promising development potential for broadband near-infrared fiber and laser materials. [ABSTRACT FROM AUTHOR]

The TFe grade of the mixed magnetic concentrate from a Liaoning iron ore processing plant is 53.92%. The main iron minerals are magnetic/hematite and the main gangue minerals are quartz. TD-II collector is used for reverse flotation in tins concentrator, but the pulp temperature Is 40 °C, winch leads to waste of resources. In order to improve the production index, a new low temperature collector DZ with multipolar base independently developed by Northeastern University Is used for reverse flotation of the mixed magnetic concentrate in thus concentrator. The effects of DZ dosage, pulp pH value, flotation temperature, starch dosage and CaO dosage on the flotation behavior of the mixed magnetic separation concentrate were investigated. For the mixed magnetic concentrate with TFe grade 53.92%, a new low temperature collector DZ was used under the conditions of flotation temperature 15 ± 2 °C, pulp pH value 9, depressant starch dosage 750 g/t, collector DZ dosage 150 g/t, and no activator was added. The flotation lockedcycle test of "one roughing, two cleanings and three scavergings" showed that a flotation concentrate with TFe grade 65.24% and iron recovery of 93.03% can be obtained, whereas under the conditions of flotation temperature 40 ± 2°C, pulp pH value 11, starch dosage 900 g/t, CaO dosage 900 g/t and collector TD-II dosage 350 g/t, a flotation concentrate with TFe grade 65.47% and iron recovery 90.71% can be obtained through the lockedcycle flotation test of "one roughing, one cleanings and three scavengings". The product inspections for the flotation concentrates obtained from the new low-temperature collector DZ and from the field reagent TD-II were carried out. By comparing the flotation results with the product inspection, t can be found that the new low-temperature collector DZ is a high-efficiency and high-selectivity low-temperature flotation collector, which can effectively solve the problem of energy waste in the reverse flotation process of the concentrator, save the beneficiation cost and improve the resource utilization efficiency. [ABSTRACT FROM AUTHOR]

The gold grade in a gold ore in Sichuan province is 3.74 g/t, which exists in the form of natural gold wkh fine particle size and Is distributed in pyrite in the form of wrapped gold, intergranular gold and fissure gold. After Knelsen gravity separation test, some qualified gold concentrate can be obtained, but the tailings have high gold grade, which caused by the loss of some undissociated natural gold and some gold-carrying sulfide. In order to further reduce the gold grade of the Knelson tailings, it is necessary to optimize the parameters of the Knelsen gravity separation process and adopt a combined process to recover the remaining sulfide gold-bearing sulfide minerals, so as to reduce the gold grade of tailings and improve the overall gold recovery. The natural gold embedded in pyrite and filled in pyrite particles can be recovered with pyrite flotation. Therefore, Knelsen gravity separation and flotation process was used to carry out the test. The optimum Knelsen gravity separation conditions are as follows: grinding fineness 70= passing 0. 074 mm, gravity multiple 90 G, liquid water volume of 9 L/min. A gold concentrate with gold grade of 67 g/t and recovery of 80.72% can be obtained under these conditions. Flotation condition test has been carried out for Helen's gravity separation tailings, and the optimal reagent regime and operating parameters have been determined as follows: the dosage of the activator copper sulfate 100 g/t, the collector (butyl xanthate and ammonium dibutyl dtthiophosphate 2 : 1) dosage 40 g/t, the dosage of the frother pine oil 20 g/t and the roughing time 3 min. A gold flotation concentrate with gold grade of 11. 04 g/t and operation recovery of 87.23% can be obtained under these conditions. According to the best conditions, the flotation process of "one roughing, two cleanings and two scavengings" has been used to carry out the locked-cycle test of the gravity separation-flotation. A gravity separation concentrate with gold grade of 56.6 g/t and gold recovery of 73.81% and a flotation gold concentrate with gold grade of 63.1 g/t and gold recovery of 24.25% have been obtained, with gold grade of 0.09 g/t and gold recovery of 1.92% in the flotation tailing. [ABSTRACT FROM AUTHOR]

Abstract: Nuclear magnetic resonance based measurements of small molecule mixtures continues to be confronted with the challenge of spectral assignment. While multi-dimensional experiments are capable of addressing this challenge, the imposed time constraint becomes prohibitive, particularly with the large sample sets commonly encountered in metabolomic studies. Thus, one-dimensional spectral assignment is routinely performed, guided by two-dimensional experiments on a selected sample subset; however, a publicly available graphical interface for aiding in this process is currently unavailable. We have collected spectral information for 360 unique compounds from publicly available databases including chemical shift lists and authentic full resolution spectra, supplemented with spectral information for 25 compounds collected in-house at a proton NMR frequency of 900MHz. This library serves as the basis for MetaboID, a Matlab-based user interface designed to aid in the one-dimensional spectral assignment process. The tools of MetaboID were built to guide resonance assignment in order of increasing confidence, starting from cursory compound searches based on chemical shift positions to analysis of authentic spike experiments. Together, these tools streamline the often repetitive task of spectral assignment. The overarching goal of the integrated toolbox of MetaboID is to centralize the one dimensional spectral assignment process, from providing access to large chemical shift libraries to providing a straightforward, intuitive means of spectral comparison. Such a toolbox is expected to be attractive to both experienced and new metabolomic researchers as well as general complex mixture analysts. [Copyright &y& Elsevier]