IGNITION AND COMBUSTION OF SINGLE SOLID PARTICLES AS NON-ISOTHERMAL METHODS OF CHEMICAL KINETICS

The ignition and combustion of single particles of crystalline boron continue to produce major scientific interest due to the particularities of the process and diversity of potential applications of boron compounds. The full valorization of boron energetic potential is a very current scientific challenge. The objective of the paper is to systematize the methodology for evaluating the kinetic parameters of boron ignition and combustion reactions in various oxidizing gaseous environments. Experimental dependencies between the ignition temperature and the particle size, as well as the combustion time as a function of oxidizing temperature are used for the calculation of the kinetic constants. As a main result, the kinetic parameters of the ignition and combustion reactions of boron in oxygen and water vapor are calculated.

Crystalline boron monosulfide nanosheets with tunable bandgaps

Two-dimensional (2D) boron monosulfide (BS) nanosheets are predicted to have several stable phases and unique electronic structures, endowing them with interesting attributes, including superconducting, thermoelectric, and hydrogen storage properties. In...

Single-crystalline boron-doped diamond superconducting quantum interference devices with regrowth-induced step edge structure

Superconducting quantum interference devices (SQUIDs) are currently used as magnetic flux detectors with ultra-high sensitivity for various applications such as medical diagnostics and magnetic material microstructure analysis. Single-crystalline superconducting boron-doped diamond is an excellent candidate for fabricating high-performance SQUIDs because of its robustness and high transition temperature, critical current density, and critical field. Here, we propose a fabrication process for a single-crystalline boron-doped diamond Josephson junction with regrowth-induced step edge structure and demonstrate the first operation of a single-crystalline boron-doped diamond SQUID above 2 K. We demonstrate that the step angle is a significant parameter for forming the Josephson junction and that the step angle can be controlled by adjusting the microwave plasma-enhanced chemical vapour deposition conditions of the regrowth layer. The fabricated junction exhibits superconductor–weak superconductor–superconductor-type behaviour without hysteresis and a high critical current density of 5800 A/cm2.

Crystal Growth and some Properties of Tm(Al1-xMox)B4 Synthesized by Al-Flux

Crystals of the solid solution Tm(Al1-xMox)B4(x = 0.002 - 0.050) were grown from Tm2O3, metal Mo and crystalline boron powders as starting materials under an Ar atmosphere at 1773 K for 5 h. Tm(Al1-xMox)B4crystals were obtained as a single phase in the case of Al1-xMoxflux (x = 0.005 and 0.010). Tm(Al1-xMox)B4crystals at a maximum size of about 2.2 mm were obtained in the shape of a flake, and together with needle-like crystals of MoAlB and an unknown phase using Al0.970Mo0.030flux. The lattice constants of Tm(Al1-xMox)B4(x = 0.005 - 0.010) crystals were determined to be larger compared to those obtained for TmAlB4. This is related to the fact that the ionic radius of Mo is larger than the ionic radius of Al. When the Al position in the TmAlB4structure was substituted with Mo having a large ionic radius, the hardness hardly changed. In contrast to TmAlB4, no antiferromagnetic transition could be observed for Tm(Al0.995Mo0.005)B4, indicating that the disorder introduced by Mo-doping disrupted the magnetic transition.