Influence of Different Beam Oscillation Patterns in Electron Beam Welding of Niobium Sheets with Different Thickness

The electron beam welding of the tubes and the half-cells for our 1.3 GHz single-cell superconducting radiofrequency (SRF) cavities is complex due to the different thicknesses of the tubes and the half-cells in the iris region. However, the mechanical properties and microstructure of the iris welds in niobium SRF cavities have barely been explored in previous studies. For high-quality iris welds, welding experiments of niobium sheets of 2 mm and 2.8 mm were carried out under different oscillating conditions. The results show that welding with no oscillation or sinusoidal oscillation may not be applied in actual welding owing to the large misalignment of the bottom surface. The weld grains were not significantly refined through beam oscillation. The joints with infinity oscillation had a higher elongation than circular oscillation, which exhibited a brittle fracture in the tensile tests at 77 K. Nevertheless, the texture of the weld with infinity oscillation implies poor formability, so the feasibility of infinity oscillation in actual welding needs verification in future study

Multi-organ protection of ulinastatin in traumatic cardiac arrest model

Abstract Background Post-cardiac arrest syndrome, which has no specific curative treatment, contributes to the high mortality rate of victims who suffer traumatic cardiac arrest (TCA) and initially can be resuscitated. In the present study, we investigated the potential of ulinastatin to mitigate multiple organ injury after resuscitation in a swine TCA model. Methods Twenty-one male pigs were subjected to hemodynamic shock (40% estimated blood loss in 20 min) followed by cardiac arrest (electrically induced ventricular fibrillation) and respiratory suspension for 5 min, and finally manual resuscitation. At 5 min after resuscitation, pigs were randomized to receive 80,000 U/kg ulinastatin (n = 7) or the same volume of saline (n = 9) in the TCA group. Pigs in the sham group (n = 5) were not exposed to bleeding or cardiac arrest. At baseline and at 1, 3, and 6 h after the return of spontaneous circulation, blood samples were collected and assayed for tumor necrosis factor-alpha, interleukin 6, and other indicators of organ injury. At 24 h after resuscitation, pigs were sacrificed and apoptosis levels were assessed in samples of heart, brain, kidney, and intestine. Results One pig died in the ulinastatin group and one pig died in the TCA group; the remaining animals were included in the final analysis. TCA and resuscitation caused significant increases in multiple organ function biomarkers in serum, increases in tumor necrosis factor-alpha, and interleukin 6 in serum and increases in the extent of apoptosis in key organs. All these increases were lower in the ulinastatin group. Conclusion Ulinastatin may attenuate multiple organ injury after TCA, which should be explored in clinical studies

Migratory fishbones in the pharynx: A report of two cases

Abstract The possibility of fishbone migration into the surrounding tissues, especially in cases where it cannot be identified on routine inspection. Early diagnosis of migratory fishbone and therapeutic management are essential for optimal patient survival

Calculated Outstanding Energy-Storage Media by Aluminum-Decorated Carbon Nitride (g-C3N4): Elucidating the Synergistic Effects of Electronic Structure Tuning and Localized Electron Redistribution

Hydrogen, as an important clean energy source, is difficult to store and transport, which hinders its applications in real practice. Developing robust yet affordable storage media remains to be a challenge for scientists. In this study, Ab Initio Molecular Dynamics (AIMD) simulations were employed to evaluate the performance of aluminum (Al) decorated carbon nitride (g-C3N4, heptazine structure) in hydrogen storage; and a benchmarking study with Mg-doped g-C3N4 was also performed to provide theoretical insights for future study. We found that each 2 × 2 supercell can accommodate four Al atoms, and that partial charge from single Al sites can be transferred to adjacent nitrogen atoms of g-C3N4. These isolated Al sites tend to be electronically positive charged, serving as active sites for H2 adsorption, predominately by triggering enhanced electrostatic interactions. The H2 molecules are adsorbed by both Al and N atoms, and are easily polarized, giving rise to electrostatic interactions between the gas molecules and the surface. Effective adsorption sites were determined by electronic potential distribution maps of the optimized configurations. Each 2 × 2 supercell can adsorb up to 36 H2 molecules, and the corresponding adsorption energies are within the range of −0.10 to −0.26 eV. The H2 storage capacity of the Al-decorated g-C3N4 is 7.86 wt%, which surpasses the goal of 5.5 wt%, set by the US department of energy. This proposed Al-decorated g-C3N4 material is therefore predicted to be efficient for hydrogen storage. This work may offer some fundamental understandings from the aspect of electronic sharing paradigm of the origin of the excellent hydrogen storage performance by metal decorated 2D materials, acting as an demonstration for guiding single metal atom site-based materials’ designing and synthesis

Microemulsion Oil Displacement Effect of Fracture Reservoirs

In order to compare the oil repellent effect of microemulsion drive and water drive, the remarkable effect of improving recovery rate of microemulsion drive is proved from the microemulsion aspect by analyzing the crack core oil drive experiment and the distribution law of the residual oil in the pore. The experimental results show that the yield rate of microemulsion drive can increase by 10.8% compared with the water drive, and the final recovery rate is as high as 49.7%, which shows that the recovery rate of microemulsion drive system has a significant effect. The proportion of residual oil with pore decreased with the decrease of pore radius, which shows that the pore radius has a significant effect on the distribution of residual oil. And compared with the matrix core, the proportion of residual oil pore in the fissure core is larger and the oil removal efficiency is relatively low