Effects of Oxygen Partial Pressure and Substrate Temperature on the Structure and Morphology of Sc and Y Co-Doped ZrO2 Solid Electrolyte Thin Films Prepared via Pulsed Laser Deposition

Scandium (Sc) and yttrium (Y) co-doped ZrO2 (ScYSZ) thin films were prepared on a SiO2-Si substrate via pulsed laser deposition (PLD) method. In order to obtain good quality thin films with the desired microstructure, various oxygen partial pressures (PO2) from 0.01 Pa to 10 Pa and substrate temperatures (Ts) from 25 °C to 800 °C were investigated. X-ray diffraction (XRD) patterns results showed that amorphous ScYSZ thin films were formed at room substrate temperature while cubic polycrystalline thin films were obtained at higher substrate temperatures (Ts = 200 °C, 400 °C, 600 °C, 800 °C). Raman spectra revealed a distinct Raman shift at around 600 cm−1 supporting a cubic phase. However, a transition from cubic to tetragonal phase can be observed with increasing oxygen partial pressure. Photoemission spectroscopy (PES) spectra suggested supporting analysis that more oxygen vacancies in the lattice can be observed for samples deposited at lower oxygen partial pressures resulting in a cubic structure with higher dopant cation binding energies as compared to the tetragonal structure observed at higher oxygen partial pressure. On the other hand, dense morphologies can be obtained at lower PO2 (0.01 Pa and 0.1 Pa) while more porous morphologies can be obtained at higher PO2 (1.0 Pa and 10 Pa).

Defect engineering of BCZT-based piezoelectric ceramics with high piezoelectric properties

The intrinsic conduction mechanism and optimal sintering atmosphere of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) ceramics were regulated by Mn-doping element in this work. By Hall and impedance analysis, the undoped BCZT ceramics exhibit a typical n-type conduction mechanism, and the electron concentration decreases with the increasing oxygen partial pressure. Therefore, the undoped ceramics exhibit best electrical properties (piezoelectrical constant d33 = 585 pC·N−1, electro-mechanical coupling factor kp = 56%) in O2. A handful of Mn-doping element would transfer the conduction mechanism from n-type into p-type. And the hole concentration reduces with the decreasing oxygen partial pressure for Mn-doped BCZT ceramics. Therefore, the Mn-doped ceramics sintered in N2 have the highest insulation resistance and best piezoelectric properties (d33 = 505 pC·N−1, kp = 50%). The experimental results demonstrate that the Mn-doping element can effectively adjust the intrinsic conduction mechanism and then predict the optimal atmosphere.

Study on the Efficacy and Safety of Ambroxol Combined with Methylprednisolone in Patients with Acute Lung Injury

Background. There is no better treatment method towards paraquat-induced acute lung injury (ALI) at present. Ambroxol combined with methylprednisolone exhibits a significant improvement effect on ALI treatment, whereas their mechanism in ALI is still unclear. Methods. 64 patients with ALI caused by paraquat poisoning brought to our hospital from January 2015 to January 2018 were selected. They were separated into a combined treatment group (CTG) and a routine treatment group (RTG) on the basis of different treatment methods. The survival of patients was observed after 7 days of treatment. Arterial blood gas, oxygen partial pressure (PaO2), partial pressure of carbon dioxide (PaCO2), oxygenation index (PaO2/FiO2), patient’s spontaneous respiratory rate (RR), tidal volume (VT), and positive end-expiratory pressure (PEEP) were observed before and after treatment for 7 days. Interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were analyzed. The differences of indexes between the dead patients and the survivors were observed, and the potential predictive value of death was analyzed. Results. After treatment, the indexes of patients were significantly improved in both groups compared with those before therapy. Further comparison showed that the improvement of PaO2, PaCO2, and PaO2/FiO2 in CTG was obviously higher than that in RTG ( p < 0.05 ). The improvement of RR, PEEP, and VT in CTG was obviously higher than that in RTG ( p < 0.05 ). The decreased degree of IL-6 and TNF-α in CTG was higher than that in RTG ( p < 0.05 ). The 7-day mortality rate of 64 patients was 39.06%, and there was no obvious difference in the 7-day survival rate in both groups ( p = 0.649 ). IL-6 and TNF-α were expected to be potential prediction indexes of paraquat-induced ALI. Conclusion. Ambroxol combined with methylprednisolone significantly improved the oxygen partial pressure and oxygenation index of patients with paraquat-induced ALI and inhibited the inflammatory response of patients.

Li-Ion-Trapping-Induced Degradation Mechanism of Colored State in Tungsten Oxide Electrochromic Films

Aiming to investigate the degradation mechanism of their colored states, tungsten oxide films with different oxygen/tungsten ratio were prepared by direct current reactive magnetron sputtering through adjusting the oxygen partial pressure. After a long-term cycling test, the sample prepared under low oxygen partial pressure (LO#) showed an excellent cycle stability which its optical modulation amplitude remains stable at 23.6%, while the one prepared under high oxygen partial pressure (HO#) exhibited an obvious degradation process of the colored state, leading to the optical modulation amplitude decreased from 34.0% to 18.6% accompanied with a decay of ionic diffusion coefficient and electrode potential, but having an improved coloration efficiency. Combined with various structural characterizations, including SEM, LA-ICP-MS, Raman and XPS, we demonstrate such colored state degradation is attributed to the so-called shallow trap, which corresponds to the irreversible and non-coloring reaction with interstitial oxygen during the insertion of Li+ cations forming superoxides (e.g. LiO2). All these findings not only offer a new insight into the improvement of cyclic stability based on ion-exchange, but also provide a valued information to understanding the physicochemical mechanisms of degradation in electrochromic materials.

Utilization Prospects of Carbon Concentrate – a Product of Aluminium Smelting Carbon Dust Processing

The possibilities of utilization of technogenic products of aluminum production: coal foam and carbon concentrate (СС) are considered. It is proposed to utilize CC in order to extract valuable components. The regularities of the utilization process of CC by the combustion method have been studied. It was found that the content of germanium in ash is determined by the temperature and the oxygen partial pressure in the system. Gallium is concentrated in ash in an amount of 0.8 wt.% during the combustion in a fluidized bed at a temperature of 1200 °C, the germanium extraction into sublimates reaches 90 %. The results of the leaching of gallium from the ash residue in acidic and basic media are presented; the maximum gallium extraction was 90 and 94 %, respectively.

Determination of Kinetic Parameters for the Oxygen Reduction Reaction on Platinum in an AEMFC

To promote the development of anion exchange membrane fuel cells (AEMFC), an understanding of the oxygen reduction reaction (ORR) kinetics in porous gas diffusion electrodes is essential. In this work, experimental polarisation curves for electrodes with different platinum catalyst loadings and oxygen partial pressures at the cathode are fitted to a physics-based porous electrode model in the voltage range from open circuit voltage (OCV) to 0.7 V. The model is verified against polarisation curves with different anode platinum catalyst loading, and hydrogen partial pressures. The reactions are described using a two-step Tafel-Volmer pathway at the anode and concentration-dependent Butler-Volmer kinetics at the cathode. The model shows a good fit to the kinetic region with an exchange current density of 1.0e-8 A/cm2, for oxygen humidified to 95 % RH at 50 °C, a charge transfer coefficient of 0.8 and a first order dependence on oxygen partial pressure. For lower oxygen partial pressure, hydrogen crossover is needed for explaining the downward shift of the polarisation curves in the kinetic region. In the experimental data, the polarisation curves show an apparent limitation at lower hydrogen partial pressures, which can be explained by the lower rate of the Tafel step at these conditions.