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The generation and propagation of physical signals in living biosystems are continuous issues. Traditional Hodgkin-Huxley model based on ionic current conduction could not explain the fast transmission of action potential in myelinated axons and factors influencing AP velocity. We propose that the ion distribution variation induced by sodium channel generates near field quasi-static electric field at extracellular space, termed as an ephaptic field which is able to excite nearby passive axons. Our simulation reveals the static electric field generated by sodium ion channels in one node of Ranvier is unlikely to activate the ion channels at nearest neighbor node. However, the ion channels ring on a node could induce 0.01 mV membrane potential difference on the node at nearby axon located at the middle of the two nodes, assuming the internode distance is 100 μm. Together with the superposition of ephaptic feedback field by the collective motion of many neighbor parallel axons, which could activate the next node of the original axon, the action potential could propagate in a zigzag path. Our simulation result also explain the fast speed of action potential propagation observed in experiments.

In this study, Li3V2(PO4)3 (LVP) powders are prepared by a solution synthesis method. The effects of two reducing agents on crystal structure and morphology and electrochemical properties are investigated. Preliminary studies on reducing agents such as oxalic acid and citric acid, are used to reduce the vanadium (V) precursor. The oxalic acid-assisted synthesis induces smaller particles (30 nm) compared with the citric acid-assisted synthesis (70 nm). The LVP powders obtained by the oxalic acid exhibit a higher specific capacity (124 mAh g&minus, 1 at 1C) and better cycling performance (122 mAh g&minus, 1 following 50 cycles at 1C rate) than those for the citric acid. This is due to their higher electronic conductivity caused by carbon coating and downsizing the particles. The charge-discharge plateaus obtained from cyclic voltammetry are in good agreement with galvanostatic cycling profiles.

ZnFe2O4 and MgxCu0.2Zn0.82-xFe1.98O4 (where x = 0.20, 0.25, 0.30, 0.35, and 0.40) nanoparticles were synthesized by sol-gel assisted combustion method. X-ray diffraction (XRD), FTIR spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) surface area studies were used to characterize the synthesized compounds. ZnFe2O4 and the doped compounds crystallize in Fd3m space group. The lattice parameter of ZnFe2O4 is calculated to be a = 8.448(3) Å, while the doped compounds show a slight decrease in the lattice parameter with an increase in the Mg content. The particle size of all the compositions are in the range of ∼50-80 nm, and the surface area of the compounds are in the range of 11-12 m(2) g(-1). Cyclic voltammetry (CV), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS) studies were used to investigate the electrochemical properties of the different compositions. The as-synthesized samples at 600 °C show large-capacity fading, while the samples reheated at 800 °C show better cycling stability. ZnFe2O4 exhibits a high reversible capacity of 575 mAh g(-1) after 60 cycles at a current density of 100 mA g(-1). Mg0.2Cu0.2Zn0.62Fe1.98O4 shows a similar capacity of 576 mAh g(-1) after 60 cycles with better capacity retention.

Ten-parameter trial wavefunctions of the Slater type are used to estimate variationally the absorption energies and splitting of a Z2+-centre in KCl:Ca2+. The results agree fairly well with the recent experimental work by Paus and Schen (1979). The approximate pseudopotential introduced by Bartram, Stoneham and Gash (1968) is used to account for the ion size effect. The theory predicted that the impurity divalent cation is displaced towards the vacancy.

The emission energy and relaxed excited state is analyzed for the $F$ center in 16 alkali halides, in a static point-ion lattice with ion-size correction, and including lattice distortion. The emission energies follow a Mollwo-Ivey relation, disagreeing with experimental values, and the relaxed excited state is highly localized. The failure on these points indicates the need for further refinement of the model and method.

The wave function of the ground state of an F-center in caesium fluoride is calculated in a point-ion lattice with ion-size correction; it is self-consistent with the lattice distortion. The absorption energy is found to differ from the experimental data by 4% and the nearest-neighbour ions move inward towards the F-center by 10% of the lattice spacing.