Papers by Keyword: Re

Abstract: The Sr₃LnInSnO₈ (Ln = La, Pr, Nd) layered perovskites were synthesized and their structures have been determined by X-ray powder diffraction. Luminescence properties of the synthesized polycrystalline compounds Sr₃PrInSnO₈ and Sr₃NdInSnO₈ were investigated. Photoluminescence spectra of Sr₃PrInSnO₈ substantially depend on excitation wavelength unlike Sr₃NdInSnO₈ compound. The correlations between peculiarities of the crystal structures and photoluminescence properties have been discussed.

Abstract: Flow pattern and mode have a far influence on the efficiency of biological treatment systems. In order to investigate the effects of different flow patterns on the growth of Bacillus subtilis, a self-developed fluid mixing device was designed to produce different liquid fluidization. It was found that the greater Re, the more conducive to the growth of bacteria, which evidenced by the logarithmic phase shorter and reached stationary phase bacteria concentration increased; when the Reynolds number is low, growth curve of Bacillus subtilis appeared Growth - stationary - growth and cell precipitation phenomenon, both phenomena gradually disappeared when Re increases. Besides, it can consume dissolved oxygen after inoculation with Bacillus subtilis, which keeping the dissolved oxygen in the medium at a lower level (0~1mg/L)

Abstract: A novel method which is based on ensemble empirical mode decomposition (EEMD) and symbolic time series analysis (STSA) was proposed in this paper. Firstly, the vibration signal of hydraulic pump was decomposed into a number of stationary intrinsic mode functions (IMFs). Secondly, the sensitive component was extracted. Finally, the relative entropy (RE) was extracted from the sensitive components and they were used as the indicator to distinguish the faults of hydraulic pump. The research results of actual testing vibration signal demonstrated the rationality and effectiveness of the proposed method in this paper.

Abstract: Al-Ti-B-RE master alloy is an efficient long-term new refiner. Al-Ti-B-RE refiner was prepared by Al-Ti-B master alloy doped with LaF₃, La-rich RE carbonate and Ce respectively. This paper studies the effect of different type and mass fraction of RE on the Second Phase Particles distributions and shape in Master Alloys. The addition of RE have a certain effect of refining TiAl₃ and TiB₂ intermediate phase. Moreover, it prevents aggregation of TiB₂ intermediate phase. As the different type and addition of RE has an effect on the microstructure of master alloy, then the reasonable addition of RE is put forward.

Abstract: Ferro-matrix friction material was obtained by in-situ carbothermal reduction from vanadium-bearing titanomagnetite in vacuum environment. The effect of RE addition (0 ~0.3 wt.%) on the microstructure and properties of ferro-matrix friction material was investigated. As a result, compared with the specimen without RE, those with RE has better connection of substrates and smaller pores size. It results the porosity decreases and, the increase of density, micro-hardness and frictional coefficient. When the adding RE is 0.1 wt.%, the connection of substrates is best, that is to say, the pores distribution is most even and pores size is minimum. Meanwhile, the highest density, hardness and frictional coefficient are obtained with 0.1 wt.% RE addition. However, there is little influence on the properties with excessive RE addition. In addition, the morphology of vanadium-titanium carbide varies with different RE addition.

Abstract: The effects of Re on solidus/liquidus temperatures, solidification segregation characteristics of alloying elements, γ′ morphology and volume fraction as well as microstructural stability at 1150 °C have been investigated in two experimental Ni₃Al-based single crystal superalloys with and without Re (1.0 wt%) addition. The results indicated that Re addition increased the solidus/liquidus temperatures. The segregation characteristics of Ni₃Al-based single crystal superalloys were similar with Ni-based single crystal superalloys, and the solidification segregation ratios of W and Mo increased slightly due to Re addition. Meanwhile, Re addition resulted in more negative lattice misfit, more cuboidal γ′ phase and higher γ′ volume fraction. The kinetics of γ′ coarsening and rafting at 1150 °C was lowered substantially compared with the addition of Re.

Abstract: In this study, hypoeutectic Al-Si casting alloy was investigated to obtain high strength, according to alloying of Cu Mg, refining of Al-5Ti-B master alloy, modifing of Re and T6 heat treatment. The experimental results show that the mechanical properties of the tested alloy reach peak when addition of Al-5Ti-1B alloy is 1.0% after heat treatment, especially the yield strength, correspondingly, microstructure distribution gets to the best state. When Al-5Ti-1B exceeds 1.0%, the mechanical properties descend gradually. The metallic compounds of Mg₂Si phase, CuA1₂ phase and W phase precipitated along the grain boundary and strengthened dispersively can improve mechanical properties of the tested alloys. The yield strength of samples added 0.1% Re (La 50%, Ce 40%) increases slightly, simultaneously, the tensile strength and elongation decreases. After 0.1% Re, the mechanical properties get down.

Abstract: In this paper 7075 aluminum alloy is studied as the object, through adding different percentages of the rare earth elements expecting to optimize alloy formula and find the optimal dosage of rare earth in order to improve the microstructure and properties of weld. The results show that when the rare earth content reaches 0.3%, alloys tensile strength comes to 388.39 MPa, and extensibility 18.22%. Compared with the control group, tensile strength is increased about 8.4%, extensibility about 14.7%, and the integrative mechanical performance is optimal. Metallographic research shows that accession of rare earth elements have perfect refinement effect to the microstructure of 7075 aluminum alloy and can improve the quality of weld.

Abstract: The determination method of ScSe and Re in uranium ore with ICP-AES has been developed. The determination limits of ScSe and Re are 0.03μg/ml0. 03μg/ml0.016μg/ml respectively. The RSD is less than 8% , and the recoveries are 96% ~106%.

Abstract: RE nanophase composite material between the grain size 30nm and 100nm are prepared by the method of mechano-chemistry，in which the material’s adsorptive capacity to metal base is checked，and the nature of anti-friction as well as self-repairing effectiveness to the surface of abrasion is tested by four-ball friction wear testing machine. The results show that RE nanophase composite material prepared by the method of mechano-chemistry has a good adsorptive capacity to metal base，and the wear surface can be covered and repaired under dynamic condition；RE nanophase composite material used as anti-friction material is test and verified.