Beijing Institute of Petrochemical Technology

About: Beijing Institute of Petrochemical Technology is a education organization based out in Beijing, China. It is known for research contribution in the topics: Catalysis & Corrosion. The organization has 2468 authors who have published 1937 publications receiving 19270 citations.

Synthesis and photoluminescence properties of Eu3+-doped ZrO2 hollow spheres

Abstract: ZrO2:Eu3+ hollow spheres were successfully fabricated with the resin microspheres as the template. The sample characterizations were carried out by means of x-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence spectra. XRD results revealed that Eu3+-doped samples were pure t-ZrO2 phase after being calcined at 873 K. SEM results exhibited that this Eu3+ doped ZrO2 was hollow spheres; the diameter and thickness of which were about 450 and 50 nm, respectively. Upon excitation at 394 nm, the orange-red emission bands at the wave length longer than 570 nm were from 5D0 → 7FJ (J = 1, 2) transitions. The asymmetry ratio of (5D0 → 7F2)/(5D0 → 7F1) intensity is about 1.61, 1.26, 1.42, 1.42, 1.40, and 1.38 for the Eu3+ concentration 0.4, 0.7, 1.0, 1.5, 2.0, and 2.5 mol%, respectively. These values suggest that the asymmetry ratio of Eu3+ ions is independent of the doping concentration. The optimal doping concentration of Eu3+ ions in ZrO2 is 1.5 mol%. According to Dexter’s theory, the critical distance between Eu3+ ions for energy transfer was determined to be 16 A.

Evolution Behaviors and Mechanisms of Internal Crack Healing in Steels at Elevated Temperatures

Abstract: The evolution behaviors and mechanisms of internal crack healing in three different kinds of steels, including 20 high-quality carbon structural steel, 30Cr2Ni4MoV steel, and SUS304 stainless steel, at elevated temperatures were systematically investigated. The morphology of the crack healing zone was observed using an optical microscope (OM) and a scanning electron microscope (SEM). The grain boundary character distribution evolution of the crack healing zone was investigated using electron backscatter diffraction (EBSD). The results show that the existence of two crack healing mechanisms is confirmed in all three experimental steels. Crack healing is controlled by atomic diffusion at lower temperatures 1173 K (≤ 900 °C) and depends mainly on recrystallization and grain growth mechanisms at higher temperatures 1273 K (≥ 1000 °C). Atomic diffusion provides materials for recrystallization and grain growth in the crack healing zone. Recrystallization leads to rapid crack healing, and grain growth facilitates microstructural homogenization and elimination of the crack healing zone. The process of internal crack healing can be divided into five stages.

Effect of operating parameters on sulfide biotransformation to sulfur.

Abstract: A laboratory-scale bioreactor with polyethylene semi-soft packing was constructed and utilized to determine the efficiency of sulfide biotransformation to sulfur under various operating parameters. Sodium sulfide dissolved in tap water was pumped into the bioreactor as sulfide for biological desulfurization. The sulfide, sulfur and sulfate-S in the effluent and the sulfide purged as gas-phase H2S were determined to investigate the effects of operating parameters, such as pH, DO, hydraulic retention time (HRT), temperature and salinity, on the sulfide oxidation products. The activity of bacteria was highest at pH 7.8–8.2. The maximal sulfide removal load was 7.25 kg/(m 3 day), with a 322.07 mg/L influent sulfide concentration and 4.80 mg/L DO. The increase of DO value corresponds to a decrease in the sulfur yield. The reactor had the highest sulfide removal load and sulfur yield at 2.55 mg/L DO. HRT had little effect on desulfurization efficiency when the sulfide removal load was kept constant. The most effective desulfurization temperature was 33°C. The sulfide removal load decreased from 2.85 to 0.51 kg/(m 3 day) with increasing salinity from 0.5% to 2.5% (m /m).