Reaction mechanism of lanthanum nitrate-doped Mo–La material during solid–liquid spray doping processing

At three critical temperatures which were obtained by thermo-gravimetry-differential thermal analysis–differential scanning calorimetry（TG/DTG/DSC）curves of lanthanum nitrate crystal, the air thermal decomposition experiments and solid–liquid spray doping simulation procedures of lanthanum nitrate crystal were carried out, and their products were analyzed by X-ray diffraction（XRD）. Meanwhile, the spray doping processing of Mo O2–50 wt% La（NO3）3composite powder was undergone with lanthanum nitrate solution as the dopant,and doped Mo O2powder was analyzed by XRD. The results demonstrate that during the traditional solid–liquid spray doping processing, lanthanum nitrate, in the form of either crystal or aqueous solution, would be converted into La（NO3）3á4H2O by the dehydration reaction, rather than be decomposed to La2O3and NO or NO2. Therefore, it is inferred that the oxynitride gas produced from the process is attributed to the decomposition of residual HNO3in lanthanum nitrate crystal. The source of HNO3is supported by the chemical composition of lanthanum nitrate crystal.

Preparation and Properties of Lanthanum Trivalent Ion Doped TiO_2 Nanopowders by Liquid Plasma Spray

The lanthanum trivalent ion doped TiO2 nanopowders were prepared by liquid plasma spray with solution of titanium tetra-tert-butoxide and alcohol as feedstock and La(NO3)3·6H2O as doping component. The photocatalytic activity of samples at different doping concentrations in photocatalytic degradation of methyl orange was discussed. The powders were characterized by Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD), and the effect of doped ion on the pattern, phase composition and crystallite sizes were analyzed. The results indicated that lanthanum trivalent ion doped TiO2 nanopowders could be prepared by liquid plasma spray. Lanthanum trivalent ion doping increased the photocatalytic activity of TiO2 greatly, the optimal doping concentration was 0.5%. The doped powders were the mixture of anatase phase and rutile phase. The contents of anatase phase decreased firstly and then increased with an increase in the contents of lanthanum trivalent ion. Doping lanthanum trivalent ion could make the TiO2 nanopowders uniform and reduced its particle size.

Application of Modified Gastric Tube Placement in Patients with Indwelling Gastric Tube

Objective:To explore the effect of modified nasogastric tube placement and Rehabilitation New Liquid Spray in patients with indwelling gastric tube.Methods:Eighty-six cases with indwelling gastric tube in our hospital from January 2020 to May 2021 were randomly selected and divided into the reference group and the research group.The reference group was treated by modified gastric tube placement,and the research group was given the Rehabilitation New Liquid Spray intervention.The effect of the interventions on two groups was observed.Results:The incidence of nasal mucosal injury in the research group was lower than that in the reference group,and the incidence of pharyngeal mucosal injury in the research group was lower than that in the reference group(P<0.05).The pain score of the study group was lower than that of the reference group at 8 h,12 h and 24 h after replacement,and the incidence of hoarseness,swallowing discomfort and dry oropharynx was lower than that of the reference group(P<0.05).Conclusion:The application of modified gastric tube placement and Rehabilitation New Liquid Spray intervention in patients with indwelling gastric tube can effectively reduce the nasopharyngeal injury and improve the pain of catheterization.

Coupled Lagrangian impingement spray model for doublet impinging injectors under liquid rocket engine operating conditions

To predict the effect of the liquid rocket engine combustion chamber conditions on the impingement spray, the conventional uncoupled spray model for impinging injectors is extended by considering the coupling of the jet impingement process and the ambient gas field. The new coupled model consists of the plain-orifice sub-model, the jet-jet impingement sub-model and the droplet collision sub-model. The parameters of the child droplet are determined with the jet-jet impingement sub-model using correlations about the liquid jet parameters and the chamber conditions.The overall model is benchmarked under various impingement angles, jet momentum and offcenter ratios. Agreement with the published experimental data validates the ability of the model to predict the key spray characteristics, such as the mass flux and mixture ratio distributions in quiescent air. Besides, impinging sprays under changing ambient pressure and non-uniform gas flow are investigated to explore the effect of liquid rocket engine chamber conditions. First, a transient impingement spray during engine start-up phase is simulated with prescribed pressure profile. The minimum average droplet diameter is achieved when the orifices work in cavitation state, and is about 30% smaller than the steady single phase state. Second, the effect of non-uniform gas flow produces off-center impingement and the rotated spray fan by 38°. The proposed model suggests more reasonable impingement spray characteristics than the uncoupled one and can be used as the first step in the complex simulation of coupling impingement spray and combustion in liquid rocket engines.

Lattice Boltzmann Simulation of Cavitating Flows

The onset of cavitating conditions inside the nozzle of liquid injectors is known to play a major role on spray characteristics,especially on jet penetration and break-up.In this work,we present a Direct Numerical Simulation(DNS)based on the Lattice Boltzmann Method(LBM)to study the fluid dynamic field inside the nozzle of a cavitating injector.The formation of the cavitating region is determined via a multi-phase approach based on the Shan-Chen equation of state.The results obtained by the LBM simulation show satisfactory agreement with both numerical and experimental data.In addition,numerical evidence of bubble break-up,following upon flow-induced cavitation,is also reported.