Tieyong Zuo

Controlled fabrication of hierarchical WO3 hydrates with excellent adsorption performance

Hierarchical WO3 hydrates have been synthesized via an ion exchange method using Na2WO4·2H2O as a precursor. The morphologies and phase structures of WO3 hydrates can be controlled by tuning the concentration of Na2WO4·2H2O solution. The as-synthesized urchin-like WO3·0.33H2O and flower-like WO3·H2O possess high specific surface area and numerous adsorption functional groups, such as WO and O–H bonds, on the surface. These characteristics result in excellent adsorption performance for both organic dyes and heavy metal ions from wastewater. The maximum uptake capacities of the urchin-like WO3·0.33H2O for methylene blue and Pb2+ are 247.3 and 248.9 mg g−1, respectively and those of the flower-like WO3·H2O are 117.8 and 315.0 mg g−1, respectively. The formation mechanism of such hierarchical mesoporous urchin-like WO3·0.33H2O and adsorption mechanism are studied in this paper.

High current density Sc 2 O 3 -W matrix dispenser cathode

Sc2O3-W matrix dispenser cathodes have been prepared by powder metallurgy method and tested in Pierce electron guns. The emission current density can reach 72 A/cm2 at 900°C and over 100 A/cm2 can be achieved at a temperature higher than 950°C. The emission improves and then keeps stable with time throughout the life testing period of 330 h at a continuous loading of 88 A/cm2 pulsed current density with a pulse width of 10 μs and duty cycle of 0.2%. The cathode surface is covered by a semiconductor multilayer composed of Ba, Sc and O. The emission behavior of the cathode can be explained by a semiconductor model.

Fabrication and emission property of LaC 2 -Mo cathode

A new kind of cathode, LaC₂-Mo cathode was prepared through spark plasma sintering method by using the mixed powder of LaC₂ which was prepared by vacuum melting method and molybdenum. It was found that the emission properties of LaC₂-Mo cathode increases with the LaC₂ content increasing. The emission current density of LaC₂-Mo cathode which contains 3.5wt.% LaC₂ could reach 0.90A/cm² at 1400.b whereas that of LaC₂-Mo cathode with 10wt.% LaC₂ could reach 3.02A/cm² at 1400.b. Richardson Work function of LaC₂-Mo with LaC₂ 3.5wt% is 2.53eV.

P1–30: Fabrication of Y 2 O 3 -Mo secondary electron emitters by air Plasma Spray method

Rare earth oxide (REO) doped Molybdenum metal ceramic emitters were successfully prepared by the air Plasma Spray (APS) method. Microstructure and secondary electron emission (SEE) performance were investigated. The relative uniform mixing of rare earth oxide and molybdenum have been observed. The maximum secondary electron yield is 3.3 after activation at 1100b(Mo brightness temperature) in vacuum.