Specific voltage coefficient

Factor 5. In practice, cell current density and cell voltage have a linear relationship. The slope of the line is termed the specific voltage coefficient or il -factor, a useful measure of the specific energy requirement of cells produced by different manufacturers. 

The sensitivity of the luminescence IP s in the systems employed here decreases with increasing x-ray energy more strongly than in the case of x-ray film. Therefore, this phenomenon must be compensated by using thicker lead front and back screens. The specific contrast c,p [1,3] is an appropriate parameter for a comparison between IP s and film, since it may be measured independently of the spatial resolution. Since the absorption coefficient p remains roughly constant for constant tube voltage and the same material, it suffices to measure and compare the scatter ratio k. Fig. 2 shows k as a function of the front and back screen thickness for the IP s for 400 keV and different wall thicknesses. The corresponding measured scatter ratios for x-ray films with 0,1 mm front and back screens of lead are likewise shown. The equivalent value for the front and back screen thicknesses is found from the intersection of the curves for the IP s and the film value. 

Therefore, in tire limiting case—tire surface concentration of tire reacting species is zero as all tire arriving ions immediately react—tire current density becomes voltage independent and depends only on diffusion, specifically, on tire widtli of tire Nerstian diffusion layer S, and of course tire diffusion coefficient and tire bulk concentration of anions (c). The limiting current density (/ ) is tlien given by... 

Tafel slope (Napieran loop) transfer coefficient diffusion layer thickness dielectric constant, relative electric field constant = 8.85 x 10 F cm overvoltage, polarization ohmic voltage drop, resistance polarization specific conductance, conductivity electrochemical potential of material X,... 

Battery characteristics depend strongly on the operating temperature. As a rule, both the discharge voltage and the reactant utilization coefficient are lower at lower temperatures. On the other hand, increased temperatures are conducive to side reactions (such as corrosion processes) and thus reduce battery efficiency. Therefore, each battery type is designed for a specific temperature range within which its characteristics will be within the prescribed limits. 

In the absence of any specific properties (which is wholly opposite to the case of selective membranes) these effective parameters can sometimes be related to microscopic parameters, such as the porosity and tortuosity in the materials used. Assuming that the membrane is not ion-selective with respect to the different ions, one can consider the transport numbers to be constant in all the electrolytic media. In the examples outlined below (see sections 4.4.2.2 and 4.4.2.3), it is assumed that the effective diffusion coefficients and mobilities are significantly lower than in the free electrolyte. This is due for exampie to a low porosity in the material used. Note that if these particular experimental conditions are chosen, then it implies that there is a significant ohmic drop in the eiectroiysis cell, which requires high electrolysis voltages (typically over 10 V). These conditions are not suitable for industrial applications. 

Channel Electron Multiplier (CEM) or channeltron is an electron detector that is used to multiply each electron (up to 10 times) to provide a pulse output suitable for further amplification by conventional electronic circuits. This is a bent tube that is coated with a photoelectric material (of a specific work function) with a high secondary electron coefficient. The tube is kept at a potential of about 2.5 kV. When the electrons pass through the inlet aperture of the CEM and strike the surface of the CEM, a collision of sufficient energy between the ultraviolet radiation and the CEM wall will eject at least one electron. When an electron strikes the mouth of the tube, a number of secondaries is produced that is accelerated in the channeltron. A local electric field created by the bias voltage of the power source accelerates these... 

Specific features of the Prederiks transition are revealed in the case of the simultaneous action of the electric and magnetic field. If the magnetic field is applied parallel to the nematic director H Lq, it proves to increase the effective elastic coefficient by the additional amount Ax-ff d /7r, which results in higher values of the corresponding threshold voltages (4.9) [5]. 

Choosing a thickness-polarized, thickness-vibrating piezoelectric element as an example, we can define the applied voltage V, current i, dimensions b, h, and /, and the output force and velocity F and the cross-sectional area bounded by b and / can be defined by A here it is assumed this area is electroded on the top and bottom faces of the element and that b and / are much greater than h. Treating it as a collection of discrete circuit elements as shown in Fig. lb, the Van Dyke circuit, allows the analysis of one resonance within the isolated element. Most piezoelectric materials are capacitive insulators, and the shunt capacitance Cs = bl/p h is the constant capacitance present across the element. The additional branch in the circuit represents the specific resonance being analyzed, the motional branch with inductance L, resistance R, and capacitance C. Many impedance analyzers provide this circuit as a means to model the electrical behavior of the piezoelectric element. The coupling coefficient for this... 

In practice, if we fabricate an ion-specific electrode by using a semipermeable membrane, the voltage (emf) E which we measure is dependent upon Oil and 0i2. If we wish to use the electrode to determine ion concentration Cl or C2, then we must know the appropriate activity coefficients 7. These are evaluated through the Debye-Hiickel equations. 

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