When a strong, though non-Arrhenius temperature dependence of electrical resistivity is observed, one usually concludes that the underlying mechanism is variable-range hopping. Unexpectedly, such observations are also made for many semiconductor systems at elevated temperatures, where a variable-range hopping mechanism seems unlikely. A satisfactory explanation for this observation is still lac...

Saturation behavior of allowed and forbidden ESR transition of AsO4 4- paramagnetic probe in KH2 AsO4 was studied in the wide temperature interval around the paraelectric-ferroelectric phase transition, T c . The ratios between forbidden and allowed line intensities were employed to deduce information on the electron-nuclear dipolar (END) relaxation mechanism. It was shown that a proton END rel...

– In the conventional theory of hopping transport the positions of localized electronic states are assumed to be fixed, and thermal fluctuations of atoms enter the theory only through the notion of phonons. On the other hand, in 1D and 2D lattices, where fluctuations prevent formation of long-range order, the motion of atoms has the character of the large scale diffusion. In this case the pictu...

The class Ia ribonucleotide reductase (RNR) from Escherichia coli employs a free-radical mechanism, which involves bidirectional translocation of a radical equivalent or "hole" over a distance of ~35 Å from the stable diferric/tyrosyl-radical (Y122(•)) cofactor in the β subunit to cysteine 439 (C439) in the active site of the α subunit. This long-range, intersubunit electron transfer occurs by ...

Experimental investigations of photoinduced charge transport in synthetic DNA capped hairpins possessing electron acceptor and donor stilbene chromophores at either end have established the mechanism, dynamics, and efficiency of charge transport in DNA. The mechanism for charge transport in repeating A-T base pairs (A-tracts) was found to change from single-step superexchange at short distances...

The astonishingly efficient location and excision of damaged DNA bases by DNA repair glycosylases is an especially intriguing problem in biology. One example is the enzyme uracil DNA glycosylase (UNG), which captures and excises rare extrahelical uracil bases that have emerged from the DNA base stack by spontaneous base pair breathing motions. Here, we explore the efficiency and mechanism by wh...

Van der Waals (vdW) thio- and seleno-phosphates have recently gained considerable attention for the use as “active” dielectrics in two-dimensional/quasi-two-dimensional electronic devices. Bulk ionic conductivity these materials has been identified a key factor control of their properties. However, direct evidence specific ion species’ migration at nanoscale, particularly under electric fields,...

In this work, we bridge the gap between short-range tunneling in molecular junctions and activated hopping in bulk organic films, and greatly extend the distance range of charge transport in molecular electronic devices. Three distinct transport mechanisms were observed for 4.5-22-nm-thick oligo(thiophene) layers between carbon contacts, with tunneling operative when d < 8 nm, activated hopping...

With more and more developments in wireless communication, spread spectrum modulation techniques have been widely used in various modulation systems. Frequency hopping technique is one of the types of spread spectrum system. In this paper, frequency hopping techniques are compared in a DBPSK modulation system which employs non coherent reception. Fast frequency hopping and multicarrier frequenc...

The realization of unique scientific phenomena in two-dimensional nanomaterials (2DNMs) has led to their applications several electronic fields; making it imperative understand the conduction mechanism charge carriers such systems. Though studies have been conducted on 2DNMs with pristine crystallinity, inevitable presence defects crystals requires careful consideration effect 2DNMs’ electrical...