The effect of diffusion on space-charge waves in a very thin semiconductor layer†

Convective and absolute instabilities associated with space-charge waves are described in a very thin layer of a semiconductor with negative differential mobility and embedded in an infinite dielectric region. Thermal diffusion of carriers plays an important role in the evaluation of the range of existence of convectively unstable space-charge waves,

Within the range of our approximations the forward growing space-charge waves are shown to exhibit a maximum growth rate for a frequency which is determined in terms of diffusion and parameters of the semiconductor find the surrounding dielectric medium.     

The physicochemical characteristics of nonfat set yoghurt containing some hydrocolloids

The effect of incorporating the hydrocolloids carrageenan (0.10%, 0.30%), xanthan gum (0.15%, 0.35%) and alginate (0.05%, 0.15%) in nonfat set yoghurt was examined in respect of instrumental texture profile and water‐holding capacity (WHC) of the yoghurt. The yoghurts which exhibited the similar behaviour of commercial yoghurts in terms of WHC, firmness and consistency, low adhesiveness and gumminess were analysed by difference‐from‐control sensory test. Carrageenan increased firmness, adhesiveness, gumminess and WHC at the highest concentration tested. The sensory tests did not show any significant difference between the formulations tested.