Sensitivity logarithmic

The concentration at which micellization commences is called the critical micelle concentration, erne. Any experimental teclmique sensitive to a solution property modified by micellization or sensitive to some probe (molecule or ion) property modified by micellization is generally adequate to quantitatively estimate the onset of micellization. The detennination of erne is usually done by plotting the experimentally measured property or response as a hmction of the logarithm of the surfactant concentration. The intersection of asymptotes fitted to the experimental data or as a breakpoint in the experimental data denotes the erne. A partial listing of experimental... 

Odors are characterized by quaUty and intensity. Descriptive quaUties such as sour, sweet, pungent, fishy, and spicy are commonly used. Intensity is deterrnined by how much the concentration of the odoriferous substance exceeds its detection threshold (the concentration at which most people can detect an odor). Odor intensity is approximately proportional to the logarithm of the concentration. However, several factors affect the abiUty of an individual to detect an odor the sensitivity of a subject s olfactory system, the presence of other masking odors, and olfactory fatigue (ie, reduced olfactory sensitivity during continued exposure to the odorous substance). In addition, the average person s sensitivity to odor decreases with age. 

Effect of Temperature. In addition to being often dependent on parameters such as shear stress, shear rate, and time, viscosity is highly sensitive to changes in temperature. Most materials decrease in viscosity as temperature increases. The dependence is logarithmic and can be substantial, up to 10% change/°C. This has important implications for processing and handling of materials and for viscosity measurement. 

H2O/100 kg of adsorbent. At equilibrium and at a given adsorbed water content, the dew point that can be obtained in the treated fluid is a function only of the adsorbent temperature. The slopes of the isosteres indicate that the capacity of molecular sieves is less temperature sensitive than that of siUca gel or activated alumina. In another type of isostere plot, the natural logarithm of the vapor pressure of water in equiUbrium with the desiccant is plotted against the reciprocal of absolute temperature. The slopes of these isosteres are proportional to the isosteric heats of adsorption of water on the desiccant (see... 

Sterilization of Media First-order kinetics may be assumed for heat destruction of living matter, and this leads to a linear relationship when logarithm of the fraction surviving is plotted against time. However, nonlogarithmic kinetics of death are quite often found for bacterial spores. One model for such behavior assumes inactivation of spores via a sensitive intermediate state by the mechanism ... 

Limitations in the digitizer s dynamic range can be overcome by using multiple transient recorders operating at diflerent sensitivities, or by adding logarithmic preamplifiers in the detection system. From the preceding discussion it appears, however, that quantitative analysis is not the primary area of application of LIMS. Semiquantitative and qualitative applications of LIMS have been developed and are discussed in the remainder of this article. 

The sensor is an ammonium ion-selective electrode surrounded by a gel impregnated with the enzyme mease (Figme 6-11) (22). The generated ammonium ions are detected after 30-60 s to reach a steady-state potential. Alternately, the changes in the proton concentration can be probed with glass pH or other pH-sensitive electrodes. As expected for potentiometric probes, the potential is a linear function of the logarithm of the urea concentration in the sample solution. 

A note on good practice Exponential functions (inverse logarithms, e ) are very sensitive to the value of x, so carry out all the arithmetic in one step to avoid rounding errors. 

Controlled potential methods have been successfully applied to ion-selective electrodes. The term voltammetric ion-selective electrode (VISE) was suggested by Cammann [60], Senda and coworkers called electrodes placed under constant potential conditions amperometric ion-selective electrodes (AISE) [61, 62], Similarly to controlled current methods potentiostatic techniques help to overcome two major drawbacks of classic potentiometry. First, ISEs have a logarithmic response function, which makes them less sensitive to the small change in activity of the detected analyte. Second, an increased charge of the detected ions leads to the reduction of the response slope and, therefore, to the loss of sensitivity, especially in the case of large polyionic molecules. Due to the underlying response mechanism voltammetric ISEs yield a linear response function that is not as sensitive to the charge of the ion. 

Sensitivity is defined as the exposure energy necessary for 50% resist thickness remaining in the exposed areas. Contrast values are assessed by measuring the slope of the linear portion of the curve obtained by plotting the thickness of the relief image as a function of the logarithm of the exposure energy (15). The film thickness was measured with a Nanospec AFT film thickness monitor (Nanometrics). 

The peak current is proportional to the substrate concentration and to the square root of the scan rate as for a simple diffusion-controlled wave. The proportionality coefficient is slightly larger, 0.527 instead of 0.446. Correspondingly, the wave is thinner, in the ratio 1.51/1.86. As with the EC mechanism, the peak potential is more sensitive to the follow-up reaction. It varies linearly with the logarithm of the scan rate, of the rate constant of the dimerization reaction, and of the substrate concentration. The rates of these variations are summarized in Table 2.1, where they can be compared to the values characterizing other mechanisms, hence serving as diagnostic... 

A Calculations containing logarithms and/or differences in reciprocals are very sensitive to rounding. Be careful not round intermediate values. 

The characteristic calibration curve is shown in Figure 11.21 on a logarithmic scale, over a range from 30 to 550°C. In the region between 150 and 450°C, the maximum sensitivity is seen. Beyond 500°C, the calibration curve tends to flatten out dramatically, and the sensitivity of measurement achievable in this region is limited, as shown by the dashed line in Figure 11.21, which represents the relative temperature sensitivity of the observed fluorescence lifetime, smx defined as... 

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