Highest carrier transport

The challenging information of this contribution is that in the short time limit a PTS crystal behaves like a conventional semiconductor as far as carrier transport is concerned. Clearly, more work is required, notably, quantitative assessments. However, for reasons of conclstency, the drift velocities measured at highest fields employed in this study cannot exceed those measured earlier (4). This yields a mobility of order 10 cm (Vs)"l, A similar estimates results from the schubweg travelled by a carrier before immobilized by a large barrier. It has to be shorter than the distance travelled between localization events (-10 pm). The conclusion is that carrier motion is polaronic as described by Cade and Mova-ghar (27). 

Most common electron transporters are derived from heterocyclic aromatic compounds, either as pure organic materials or as metal coordination complexes. Pure organic molecules such as phenanthrolines, oxidiazoles, and triazoles can have high electron mobilities (Figure 25). Some of the highest carrier mobilities for amorphous molecular materials have been reported for oligofluorenes (lO -lO cm V j-i) 305,313 inefficient carrier... 

CNTs in polymer-CNT composites are efficiently debundled and isotropically dispersed in polymer matrices, the efficient interaction between CNT and polymer provides good dispersion and a low percolation threshold, but only relatively low conductivity near and above percolation, frequently around 10 s cm is achieved at close to 2wt% CNT loading [70, 71], The polymer layer in the intemanotube connections is supposed to be the highest resistance section in the electrical pathway. This polymer layer is a barrier to efficient carrier transport between CNTs, and models for conductivity based on fluctuation-induced tunneling have been proposed [72]. A power law related to percolation theory can be used to model conductivity in the following form ... 

Cryptands of type 7-9 and derivatives thereof carry alkali cations [6.4], even under conditions where natural or synthetic macrocycles are inefficient. The selec-tivities observed depend on the structure of the ligand, the nature of the cation and the type of cotransported counteranion. Designed structural changes allow the transformation of a cation receptor into a cation carrier [6.1, 6.4]. The results obtained with cryptands indicated that there was an optimal complex stability and phase-transfer equilibrium for highest transport rates. Combined with data for various other carriers and cations, they give a bell-shaped dependence of transport rates on extraction equilibrium (Fig. 11), with low rates for too small or too large... 

The kidney, liver, and spleen had the highest specific activity after administration of labeled melphalan to rats and mice [68,98], while in dogs and monkeys the highest levels of drug were in the bile [3,75,99]. No significant concentrations in the tumor were noted, and the inhibition of the tumor growth could not be attributed to interactions with proteins, DNA, or RNA within the tumor cell [68]. Cellular transport of melphalan by amino acid carrier systems has been reported [100—105]. 

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