No abstract

No abstract

Poly(β‐hydroxybutyrate) (PHB) (CH(CH3)CH2COO)n is a biodegradable polymer and it has various important applications in the biomedical field. In the present communication a comprehensive study of the normal modes and their dispersion in the α form of PHB using Urey Bradley force field is being reported. Optically active frequencies corresponding to zone center and zone boundary are assigned and characteristic features of dispersion curves are discussed. Heat capacity has been calculated via density‐of‐states using Debye relation in the temperature range 10–450 K. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

No abstract

No abstract

This work demonstrates that black phosphorene, a two dimensional allotrope of phosphorus, has the potential to be an efficient photo-thermionic emitter. To investigate and understand the novel aspects we use a combined approach in which ab initio quantum simulation tools are utilized along with semiclassical description for the emission process. First by using density functional theory based formalism, we study the band structure of phosphorene. From the locations of electronic bands, and band edges, we estimate the Fermi level and work function. This leads us to define a valid material specific parameter space and establish a formalism for estimating thermionic electron emission current from phosphorene. Finally we demonstrate how the emission current can be enhanced substantially under the effect of photon irradiation. We observe that photoemission flux to strongly dominate over its coexisting counterpart thermionic emission flux. Anisotropy in phosphorene structure plays important role in enhancing the flux. The approach which is valid over a much wider range of parameters is successfully tested against recently performed experiments in a different context. The results open up a new possibility for application of phosphorene based thermionic and photo-thermionic energy converters.

No abstract

No abstract