Figure of merit relative

For new analytical techniques to prosper, they must have demonstrated applications to real-world samples, with outstanding figures of merit relative to competing approaches. Table 10.24 opposes the prospects of conventional separation procedures and advanced in situ analyses by the currently most qualifying techniques. Lab-on-a-chip (LOC) devices are unlikely to be robust enough to cope with the moderately complex (i.e. dirty ) matrices that are real-life samples. Industrial chemists need to avoid a lot of work for every analyte and every matrix. Obstacles to solid analysis are relatively poor sensitivities, narrow linear dynamic ranges and unavailability of solid standards. The trend... 

Table 2. Second harmonic generation figures of merit relative to LiNb03 (d13 coefficient) for materials with potential for waveguide applications...

Material Csd (cm-3) (relative to NdUP) (grain diameter lOOum) Av,g (cm >) Figure of Merit (relative to NdUP) Quenching rate S(s- )... 

This figure-of-merit relative efficiency is defined as the ratio of the counts per second in the 1332.5 keV peak of 00 when the source is counted at 250 mm source-to-detector distance on the axis of the detector, to the counts per second in the 1332.5 keV peak when the same source is measured at the same distance by a 3 x 3 Nal(Tl) detector. It is strictly only relevant to wide range coaxial detectors. Planar and other low-energy detectors are not designed to cover the energy range up to 1332.5 keV. 

Figure 2.8. The slopes and residuals are the same as in Figure 2.4 (50,75,100, 125, and 150% of nominal black squares), but the A -values are more densely clustered 90, 95, 100, 105, and 110% of nominal (gray squares), respectively 96, 98, 100, 102, and 104% of nominal (white squares). The following figures of merit are found for the sequence bottom, middle, top the residual standard deviations +0.00363 in all cases the coefficients of determination 0.9996, 0.9909, 0.9455 the relative confidence intervals of b +3.5%, +17.6%, 44.1%. Obviously the extrapolation penalty increases with decreasing Sx.x, and can be readily influenced by the choice of the calibration concentrations. The difference in Sxx (6250, 250 resp. 40) exerts a very large influence on the estimated confidence limits associated with a, b, Y(x), and X( y ).

Although cSFC shows relatively poor figures of merit (speed, sensitivity, detection dynamic range and sample capacity) as well as a limited application area, its applications tend to be unique. These include solutes that can be solvated with pure SCCO2 and quantified with FID. Linear density programs typical in cSFC are ideal for homologous series found in surfactants, many prepolymers, etc. Selectivity in cSFC, which can be achieved by mobile phase density and temperature programming, relies on selective interactions with the stationary phase. Quantitative analysis in cSFC may be rendered difficult by small injected volumes the use of internal standards is recommended. 

Table 6.30 lists the main characteristics of quadrupole mass spectrometers. QMS is a relatively simple and robust analyser which does not need such a high vacuum as a sector instrument. The maximum admissible pressure at the source of the spectrometer is 10 6mbar in continuous regime and 10-5—10 4 mbar during short time intervals. Quadrupole technology assures reproducible and accurate molecular weight measurements day in and day out. For figures of merit, see Table 6.27. 

Because sensitivity depends on so many different experimental factors, NMR spectroscopists generally use the signal-to-noise ratio, SIN, as a figure of merit for sensitivity comparisons. For example, in a comparison between NMR probes or spectrometers from two vendors, the spectral SIN measured for a standard sample acquired with specified acquisition parameters and probe geometry would provide a direct indication of relative sensitivity. The SIN is calculated for an NMR experiment as the peak signal divided by the root mean square (RMS) noise, given by Equation 7.6, and is directly related to the performance of the radiofrequency coil [3,6]... 

There are several disadvantages with the image simulation method. A nearly correct structure model is needed beforehand. This is often not available, especially for relatively complicated structures. Images are compared visually and no quantitative figure of merit is used for judging how well images and simulations agree. 

Using Q/Qtnt from Table I as the basis for intercomparison, and depending on the arbitrary used to compute the s, a figure of merit for BTNEU might equally well be 1.15 (Arbitrary 1), 1.54 (Arbitrary 2), or 2.14 (Arbitrary 3). In the first case the comparison would be at the top of the isentrope, in the second case a relatively short distance down the isentrope, in the third case a relatively longer distance down the isentrope. From similar considerations, it is possible to take one s choice PETN is 3% more powerful than BTNEU (Arbitrary 1) or BTNEU is 6% more powerful than PETN (Arbitrages 2 or 3). 

Two independent means, graphical relative pressure methods, are used to obtn EW EV from peak pressure measurements. Two comparable methods obtn these figures of merit from positive impulse data. There is also described a method for detg EW Si EV from an analytical study of positive impulse data... 

Table I lists the properties of several organic materials which have been studied as single crystals. The materials are listed alphabetically according to the acronym applied to them in order to avoid the appearance of prejudice with respect to any one material. Listed are the molecular P (if known), space group and point group of the crystal, SHG powder intensity relative to urea, NLO coefficients for SHG, its transparency cutoff, and the figure of merit for SHG if known. Other aspects are...

The next logical step toward chromophore design was to conduct a spectral survey of commercially available organic compounds in order to learn some general structure-property relationships for minimization of the residual absorbance. As an easily measured figure of merit, the ratio between the minimum and maximum molar absorptivities has been used. In many cases, this ratio (expressed in percent, or more conveniently, as the minimum molar absorptivity per 100,000 L/mol-cm of maximum absorbance) is 5-10% (5000-10,000 per 100,000). (The lower the number the better the dye.) An improved figure of merit would take into account the area under the absorption curve as well as the location of the transparent window relative to the peak in the absorption. This is tantamount to calculating the dispersion from the absorption spectrum, which was too complex for this type of survey. 

From this relation it follows that a good, i.e., large, ratio of true to accidental coincidences requires a small coincidence resolving time At and a small source strength (f J<7). However, for small values of N all counting rates, Ix, l2, and /true, are small, and therefore the ratio r is not well suited as a criterion of the quality or feasibility of coincidence experiments. Indeed, a more appropriate figure of merit follows if the relative error a of true coincidences, defined by... 

In conclusion, it has been demonstrated that the pyroelectric properties of polar materials can be compared relatively simply through the measurement of a few key physical parameters (pyroelectric,dielectric and thermal coefficients) and the judicious use of appropriate figures-of-merit. It is essential that the dielectric properties are measured in the frequency range appropriate for device use, and this is typically in the range of a few to 100 Hz. The properties of many pyroelectric ceramics and thin films have been compared and it has been shown that good pyroelectric properties can be obtained from this films manufactured at relatively low temperatures, a fact that bodes well for their future applications in fully-integrated arrays. 

As noted, the figures of merit of the conventionally hot pressed samples were not high, due to the high resistivity of the samples with relatively low density. However, the temperature dependence shows an attractive increase with increasing temperature above 1000 K similar to the other rare earth boron cluster com-... 

Given that the appropriate relative permittivities of the ceramic and the polymer are respectively 1500 and 3.5, and that the d33 coefficient for the ceramic is 375 pCN-1, calculate a value for the hydrophone figure of merit and show that the units are m2 N 1. For this estimate it may be assumed that the composite has been structurally modified so that the d33 contribution is negligible. Comment on the realism or otherwise of the calculated value. 

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