Hydrogen evolution by tungsten carbonitride nanoelectrocatalysts synthesized by the formation of a tungsten acid/polymer hybrid in situ.
A step forward for tungsten: Nitrogen-rich tungsten carbonitride (WCN) nanomaterials can act as stable and efficient hydrogen evolution electrocatalysts with a much higher activity than conventional WCN materials. The use of a polymerization process provides a unique synthetic route to H₂WO₄ nanoparticles, which can then be used to synthesize the WCN-derived catalysts.


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Earley ion exchange used in tungsten smelt, it shows a lot of unsuitable places in its product. Its through function is low to 65%, and the foreign matters of Ca and Mg exceed quota. That causes the product unqualified. Through search shoot- flow technology, scientifically design the second ion exchange pillar. In shoot-flow technol-ogy, the usage of many ranks disflow distract and many ranks storaged energy distract. Its achievement that through function reach 95%, and use in product of second ammonium tungsten acid.


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Plain radiographic examinations were performed on 388 patients (adult and pediatric) using either a calcium tungstate or rare-earth screen. Radiographs were compared for overall image quality, mottle, contrast, density, and detail. The rare-earth screen produced radiographs with significantly more mottle than did the standard screen. However, this was almost never of diagnostic importance. A small but significant decrease in overall image quality also was found with the rare-earth screen. This was the result of minor differences between the grading of optimal and good. A major advantage of rare-earth screens is a 50% or more reduction in radiation exposure. The results here show that,compared with calcium tungstate screens,rare-earth screens may be used in plain radiographic examinations without a clinically important decrease in image quality.


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The heat of solution of Na₂WO₄ has been measured and the standard heat of solution calculated to be -1.6 kcal/mole. Because this heat of solution is very differnent from that calculated from previously reported heats of formation, Robert L. Graham and Loren G Hepler have measured the heat of reaction of crystalline tungstic acid(H₂WO₄) with excess aqueous sodium hydroxide and have found the standard heat of solution of AgNO₃ in water have been measured and the standard heats found to be -12.39,-8.12 and 5.42 kcal/mole, respectively. The heats of reaction and solution have been used to calculate the heats of formation of WO₄^-(aq), Na₂WO₄(c) and Ag₂WO₄(c) to be -266.6，-379.6 and -230.7 kcal/mole, respectively. The thermodynamics of solution of Ag₂WO₄ is discussed in terms of polytungstate formation.


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