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Conjugated Polymers
Published in A. Sezai Sarac, Nanofibers of Conjugated Polymers, 2017
Charge transfer between the polymer chain and dopant molecules is easy after doping neutral conjugated molecules: n-doping corresponds to reduction (addition of electron), and p-doping corresponds to oxidation (removal of electron). The soliton model was first proposed for degenerated CPs (polyacetylene [PA] in particular) and it was noted for its extremely one-dimensional character, each soliton being confined to one polymer chain. Thus, there was no conduction via interchain hopping. Furthermore, solitons are very susceptible to disorder and any defect such as impurities, twists, chain ends, or crosslinks will localize them.The application of an oxidizing potential to aromatic polymers with nondegenerate ground states destabilizes the VB, raising the energy of the orbital to a region between the VB and the CB. Removal of an electron from the destabilized orbital results in a radical cation or polaron. Further oxidation results in the formation of dications or bipolarons dispersed over a number of rings. These radical cations are the charge carriers responsible for conductivity in conjugated polymers. Because of the nondegenerate energy transitions of conjugated polymers (excluding PA), structural changes result and backbone will localize them.*
Uncertainty Sources Associated with Low-Frequency Electric and Magnetic Field Experiments on Cell Cultures
Published in Marko Markov, Dosimetry in Bioelectromagnetics, 2017
Additionally, several reports have provided evidence of neural sensitivity to the rate of change of temperature, while experiments to study such effects require extraordinary effort on the design and monitoring of exposure systems. For example, changes in the firing rate of pacemaker cells from the ganglion of Aplysia californica have been induced by total temperature changes of as little as 0.1°C when the rates of change are ∼1°C/s, corresponding to an injection of ∼1 nA into the cell (Chalker, 1982; Barnes and Greenebaum, 2006). Similar observations have also been made for the large parietal ganglion of the central nervous system of Limnaea stagnalis, where a slow increase in temperature of 1°C/min or less increases the firing rate of the pacemaker cell, and a rapid increase in temperature of 0.1°C/s or faster decreases or stops the firing (Bol’shakov and Alekseyev, 1986). In this regard, contemporary investigations are yielding physics-based insights on the nature of neural pulse transmission according to the soliton model theory, for instance, in which transmission is described as inherently thermal phenomena that can be measured electrically (Heimburg, 2007; Andersen et al., 2009) predicting sensitivity to spatiotemporal thermal stimuli (Hasani et al., 2015). Similarly, classical theory also describes neural extreme temperature sensitivity. For example, the Nernst equation is used in classical electrophysiology as a simplified starting point to model the passive equilibrium of membrane potentials (especially those excitable, e.g., neural) as a function of ion concentrations and temperature as it describes the relationship between chemical and electrical gradients across a semipermeable membrane (Kandel et al., 2000). Interestingly, little work is needed to show the fundamental temperature rate-of-change (ΔT/Δt) dependence of current flow through cell membranes predicted by the same equation (Barnes, 1984) in the order of a few nA per °C/s depending on the specific cell in question.
Interaction of bright-dark solitons in a silicon-on-insulator optical waveguide
Published in Journal of Modern Optics, 2019
Yang Wang, Weiguo Jia, Zhen Liu, Jun-Ping Zhang, Neimule Men-Ke
We set up the input pulse width of two solitons and a delay considering the influence of a dark soliton and bright soliton model of the area. We set up a bright soliton polarization angle .