Search

The combustion of carbon-based materials in a high speed stream of dissociated air is analyzed, together with the oxidation mechanism from reaction rate controlled regime through the transition to diffusion controlled oxidation. The product of the heterogeneous reaction of carbon with oxygen is known to be CO and CO2, and CO2 is generally usually neglected when surface temperature is higher than 1000K in many literatures. However, we find that CO2 plays an important role in the whole oxidation processes, and can't be ignored through the three regimes. It is shown that two different platforms existed in the diffusion controlled regime. The first platform results from a reaction of the predominant CO2 product, and the other is due to the predominant CO product reaction. In fact, the concepts of "fast" reaction and "slow" reaction are not proper, since the two are the extreme cases of the general model we proposed. As surface temperature rises, the oxidation process will change automatically from nominated "fast" reaction to " slow" reaction. The dual platform theory has been confirmed by several experimental results. [ABSTRACT FROM AUTHOR]

This review summarized the progress of researches on the active locomotion system for capsule endoscope, analyzed the moving and controlling principles in different locomotion systems, and compared their merits and shortcomings. Owing to the complexity of human intestines and the limits to the size and consumption of locomotion system from the capsule endoscope, there is not yet one kind of active locomotion system currently used in clinical practice. The locomotive system driven by an outer rotational magnetic field could improve the commercial endoscope capsule, while its magnetic field controlling moving is complex. Active locomotion system driven by shape memory alloys will be the orientated development and the point of research in the future.