A Numerical Study on Jet Release from Off-site and Mobile Hydrogen Refueling Station for Separation Distance

High-pressure hydrogen facilities are prone to jet release accidents. In the cases of immediate ignition, jet fire occurs, and delayed ignition can lead to explosion accidents. Therefore, its management is crucial to avoid leakage. In this study, the change in volume fraction of hydrogen and the flammable area around the hydrogen facility were calculated using a computational fluid dynamics model, for the cases of jet release accident in a hydrogen storage tank of off-site hydrogen refueling station and a mobile hydrogen refueling station. The leakage at the off-site hydrogen refueling station was through the opening at the top of the wall. The mobile hydrogen refueling station had hydrogen stagnated in the lower part of the wing body due to the wing body. Most of the hydrogen facilities were included in the hydrogen flammable zone after 10 s of the jet release. Further, after 30 s, the flammable distance was calculated to be approximately twice for of a mobile hydrogen refueling station as compared to a storage type hydrogen refueling station.

The Effect of γ-Ray Irradiation on Optical Properties of Single Photon Sources in 4H-SiC MOSFET

We investigated the effects of γ-ray irradiation to single photon sources (SPSs) embedded in 4H-SiC metal-oxide-semiconductors field-effect transistors (MOSFETs). After the γ-ray irradiation, the number of SPSs was temporarily increased. However, the ratio of unstable SPSs was increased with increasing the radiation dose, and such unstable ones gradually disappeared. Finally, the density of the SPSs nearly recovered that before the irradiation. We discuss a possible explanation on these phenomena in terms of interactions between mobile hydrogen atoms and interface defects.

PECULIARITIES OF STRUCTURE AND SPECTRAL-LUMINESCENT PROPERTIES OF CARBOXYMETHOXY-SUBSTITUTED CALIX[4]ARENES AND THEIR COMPLEXES WITH LANTHANIDES

Spectral-luminescent properties of a variety of carboxymethoxy-substituted p-tert-butyl-calix[4]arenes and their complexes with lanthanides (Nd, Er, Yb) that exhibit the 4f-luminescence in the IR-spectrum region have been investigated. The effect of substitution of hydrogen phenolic atoms by carboxymethoxy groups on the stability and spectral-luminescent characteristics of both the ligands and lanthanide complexes was analyzed. Thus, based on the combination of the results obtained by means of elemental analysis, mass spectrometry, IR and 1H NMR spectroscopy, and taking into account the data of pH-metric titration, spectrophotometric and luminescence measurements, it can be concluded that lanthanide ions form neutral complexes of 1:1 ratio with L1H4 - L4H4. This is explained by the presence of mobile hydrogen atoms of phenol and/or carboxyl groups in the molecules of these ligands. An increase in the number of donor substituents leads to changes in the number of solvent molecules in the series L3H4 < L1H4 < L2H4 < L4H4 from 0.8 to 2.4 for neodymium complexes, from 1.2 to 2.2 - for ytterbium complexes. Both the quantum yield and lifetime of the 4f-luminescence of the neodymium and ytterbium complexes and also the luminescence intensity of the erbium-containing compounds change in the same order.