Current channels

TABLE 1 Properties of store depletion-activated currents (channels) in smooth muscle... 

Current Channelling Effect in Magneto telluric Field Data... 

Ten Eick, R.E., Baumgarten, C.M. and Singer, D.H. (1981) Ventricular dysrhythmia Membrane basis or of currents, channels, gates, and cables. Progress in Cardiovascular Diseases, 24, 157-188. 

The signal/noise ratio of the current channel can be improved by amplifying the signal, the minimum amplification being imposed by the range of TFA (generally larger than 10 mV). 

In a similar manner, during the process of the existing metal particles growth and the deposition of new species using cathodically biased electrode in a solution of metal ions, the growing metal phase will be also localized at the sites of the surface exposure of the continuous donor centers. The reason for this is that namely these sites possess substantially enhanced electrocatalytic activity in comparison with the stoichiometric oxide surface and exhibit the properties of current channels non-restricted by the Schottky barrier at the interface with the electrolyte. Actually, a peculiar decoration of the sites of donor centers accumulation and donor clusters localization by the metal nanoparticles takes place in the dark processes of metal particle deposition onto the surface of the chemically inert wide-band-gap oxides. The increased electrocatalytic activity of the wide-band-gap semiconductor electrodes resulted from the deposition of metal nanoparticles on their surface may be also regarded as a kind of such decoration . 

Suh B-C, Hille B (2002) Recovery from muscarinic modulation of M current channels requires phosphatidylinositol 4,5-bisphosphate synthesis. Neuron 35(3) 507-520... 

Figure 1.7 Bacterial Cl channel homolog stmcture. The dimeric protein is viewed from the side (the plane of the image is perpendicular to the membrane plane). The two monomers are separated by a line down the middle of the figure. The membrane is omitted. Each monomer contains a separate pore for Cr ion permeation. Each pore contains a selectivity filter and a gating domain which is believed to involve a pH-sensitive glutamate residue. The location of the ion transit pathways and the mechanism of transport through the pores are topics of current channel research (Yin et al, 2004).

Inside the Debye sphere, strong electron acceleration takes place. The electrical field that surrounds the ion current channel accelerates the electrons toward the filaments where they are deflected on the induced magnetic field. The scenario is depicted in fig. 2. It have previously been shown that the ion filaments are generated in a self-similar coalescence process (Medvedev et al., 2004) which implies that a spatial Fourier decomposition exhibits power law behavior. As a result, the electrons are accelerated to a power law distribution function (fig. 3) as shown by Hededal et al., 2004. 

Figure 2. An ion current channel surrounded by an electric - and a magnetic field. Electrons in the vicinity of the current channels are thus subject to a Lorentz force with both an electric and magnetic component, effectively accelerating the electrons.

A poorly understood feature of electrical discharge is the phenomenon of constriction of the current channel which is often observed at high gas pressures (I, 7, 8, 9, 23, 31, 32, 39, 40, 55, 59). Several effects are present which tend to cause a narrowing of the conducting channel. They are ... 

Figures 4.3(a) and (b) are sections in the zx-plane showing the distribution of potential (( )) in the solution as cross sections of imaginary surfaces in the solution of equal potential (isopotentials) and the distribution of current as current channels with cross sections defined by traces of the surfaces. ..(n - l),n, (n + 1)... perpendicular to the isopotentials. These traces are located such that each current channel carries the same total current. Figure 4.3(a) applies to an environment of higher resistivity (e.g., water with specific resistivity of 1000 ohm-cm) and Fig. 4.3(b) to an environment of lower resistivity (e.g., salt brine, 50ohm-cm). The figures are representative of anodic and cathodic reactions, which, if uncoupled, would have equilibrium half-cell potentials of E M = -1000 mV and E x = 0 mV and would, therefore, produce a thermodynamic driving force of Ecell = E x - E M = +1000 mV. This positive Ecell indicates that corrosion will occur when the reactions are coupled. For the example of Fig. 4.3(a), the high solution resistivity allows the potential E"m at the anode to approach its equilibrium value (E M = -1000 mV) and, therefore, allows the potential in the solution at the anode interface, < )s a, to approach +1000 mV (recall that (j)s = -E"M). The first isopotential above the anode, 900 mV, approaches this value. The solution isopotentials are observed to decrease progressively and approach 0 mV at the cathode reaction site.

Fig. 4.3(b) Potential and current distribution in electrolyte with specific resistivity of 50 ohm-cm. Only one current channel is shown. These become progressively more narrow as the anode/cathode junction is approached. Current channels conduct the same current as in Fig. 4.3(a). 

Since a major variable governing corrosion is frequently the solution resistivity, emphasis is placed on analyzing qualitatively how this can be an important factor. The flux of current from anode to cathode will follow approximately semicircular channels, perpendicular to the isopotential surfaces, for the simple geometry shown in Fig. 4.3(a) and (b). The current-channel boundary surfaces have been drawn so as to define channels of fluid extending from the anode to the cathode with a... 

Fig. 4.8 Tafel polarization curves for anodic and cathodic reactions as related to the nth current channel in Fig. 4.7, illustrating the dependence of the corrosion current, lcorr, on the solution resistance, Rs...

The switching device is a commercial Pseudospark, model FS 2000 (Alstom). The rated maximum anode voltage and current are 32 kV and 30 kA. In the present application, the anode voltage is 30 kV, but the peak anode current is only 4 kA. The switch operates at the transition between the hollow cathode and superemissive modes. The switch-current rise-time is 15 ns, limited by the current channel and connection inductances. 

Figure 5.5 Typical load voltage and current. Channel 1 is current (100 A/div). Channel 2 is voltage (10 kV/div). PFN is charged to 2.5 kV.

In true cyclotrons, the orbit of a particle cannot decrease in diameter. For the puzzles here, this additional constraint would imply that a particle cannot jump to a channel of smaller diameter as it travels. It could only travel in its current channel or go to an outer one. How would this alter your answers to the other questions ... 

Fig. 26 A Current-distance retraction curves recorded with a gold STM tip (low current channel with a preamplifier limit of InA) for 0.1 mM 1,9-nonanedithiol in 1,3,5-trimethylbenzene on Au(lll)-(1 x 1), at bias=0-10V. The setpoint current before disabling the feedback was chosen at iio = 100 pA. The pulling rate was 4nms B Same conditions as in A, except that the preamplifier limit was chosen at 10 nA. The dotted lines represent characteristic regions of the low, mid and high currents...

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