Resolution characteristics

The electrical aerosol analyzer and the optical counter are used to measure particle size distributions. Describe the size range and resolution characteristics of each of these instruments. 

The monochronomator in a Raman spectrometer must have excellent stray light and resolution characteristics. 

While PMMA is an attractive material because of its resolution characteristics, its sensitivity to radiation induced degradation is low, and its dry-etching characteristics are poor. The e-beam and deep-UV exposure doses for PMMA are —100 nC cm-2 (38) and >1 Jem-2 (40), respectively. The fact that nanometer resolution is readily achieved in this material has, however, prompted many researchers to examine substituted systems in attempts to effect improved performance. 

In an effort to improve PMMA s photosensitivity further, methyl methacrylate has been copolymerized with higher percentages of the a-keto-oxime methacrylate and terpolymerized with varying amounts of methacrylonitrile. The resulting effects on resist properties, e.g., sensitivity, contrast and resolution, and plasma resistance, are reported here. The terpolymers are up to 85 times more sensitive than PMMA, and retain its high resolution characteristics. 

The photosensitivity of PMMA is significantly enhanced by the incorporation of 10 to 40 mole% 3-oximino-2-butanone methacrylate. Terpolymerization with methacrylonitrile increases that sensitivity still further, P(M-OM-CN) (69 16 15) being 85 times more sensitive than PMMA on exposure to the full output of a 1000 watt mercury lamp. Upon addition of external sensitizers, this sensitivity may be increased by an additional factor of 2 to 3. The high resolution characteristics of PMMA have been retained and the polymers in question show good plasma resistance. 

The discussion in the present section concerns only dispersive optical spectroscopy. We shall not treat the resolution characteristic of a Fourier interferometric spectrometer, which is determined by the optical path difference scanned and the apodizing function used. Nevertheless, these... 

Preparation and Resolution Characteristics of a Novel Silicone-Based Negative Resist... 

Molecular sieve chromatography depends largely on a mixture of molecules being given an opportunity to diffuse into the gel matrix. The greater the number of opportunities for this to occur, the finer the resolution achieved. Therefore, the flow rate of eluent exerts a profound effect upon the resolution characteristics of a column. As shown in Figure... 

The high-resolution characteristic of FT-ICR-MS and its potential in elucidating ion envelopes and isotope patterns of multiple-charge proteins in ESI mass spectra has stimulated the research into coupling of ESI and FT-ICR-MS. This in turn has stimulated further development of FT-ICR-MS as an MS tool (Ch. 2.4.6). 

This will result in equal resolution characteristics. 

Linear analyzers and conventional TLC scanners are standard equipment in nuclear medicine. These instruments offer high detection efficiency and resolution characteristics combined with speed of analysis, which is required for the analysis of short-lived radiopharmaceuticals. 

For Ge detectors other than the well-type, the efficiency is low, relative to Na(Tl) scintillation counters. This statement holds true for Si(Li) detectors as well (see Sec. 12.9). Lower efficiency, however, is more than compensated for by the better energy resolution of the semiconductor detector. Figure 12.32 illustrates the outstanding resolution characteristics of a semiconductor detector by showing the same spectrum obtained with a Nal(Tl) and a Ge(Li) detector. Notice the tremendous difference in the FWHM. The Ge(Li) gives a FWHM =... 

In either method, the time-resolution characteristics of the instruments employed must be sufficient to detect and follow the property change. Examples of physical properties measured in such applications include intensity of transmitted, scattered, or absorbed light (Tanaka et al. 1979 La Mer and Dinegar 1951), solution conductivity (Sohnel and Mullin 1978), heat released (Nyvlt and Pekarek 1980), light emission (Garten and Head 1963), and chemical composition of the solution (Packter 1974 Koutsoukos and Kontoyannis 1984). 

Zhao Y, Tan HH and Zhang B (2002) A high-resolution characteristics-based implicit dual time-stepping VOF method for free surface flow simulation on unstructured grids. Journal of Computational Physics 183 233-273... 

Column effects. In order to establish optimal operating conditions, it is useful to consider the effects of system parameters on the resolution characteristics of an HDC system. HDC has been described as a chromatographic method with very low capacity but very high efiBciency. For example, the calibration curves show that the spectrum of sizes from less than 100 nm to greater than 300 nm is encompassed in less than about 5% of the column void volume. On the other hand, the theoretical plate count corresponding to the marker peak is typically in the range of several thousand per foot. Comparisons in terms of the specific resolution factor, enable a more precise analysis, since both the separation factor and peak dispersion are included in its definition. A simple form for the specific resolution between two particle populations of diameter Dpi and Dp2 is [11]. 

In view of the resolution characteristics of an ED detector, spectral overlap interferences are much more common in ED-XRE than WD-XRF and require a more comprehensive correction procedure than the simple line ratio method often used in the latter technique. However, advantage can be taken of the digital form in which ED spectral data are accumulated in the multichannel analyzer, which offers information about peakshapes as well as intensity. For simple ED spectra, it may be possible to define a series of windows covering each fluorescence peak of interest (the region-of-interest approach). Peak intensities can then be determined by chaimel integration and a background correction applied by linear interpolation between the lowest and the highest channel of the window. For complex spectra, a more sophisticated approach is required, of which two have found widespread use. 

Film dosimeters. The radiation-induced change of optical absorption in various film systems has been utilized for dosimetry purposes for many decades. Although correct application of films requires controlled conditions because their response is affected by almost all environmental factors, these systems are widely used in both gamma and electron beam radiation processing. They are well suited for dosimetry of electron radiation because of their good spatial resolution characteristics, e.g., for dose distribution measurements as compared to other systems. 

Replacement of the organic solvent by D2O yielded multi-lamellar structures with no high resolution characteristics. Sonica-tion of these suspensions led to the formation of single bilayered vesicles which contained either A -THG or CBD. In these vesicles no signals from the cannabinoid protons could be detected at concentrations of A -THC or CBD twice as high as those for which PMR signals are easily determined in CDCl solution (Fig. IB). 

The choice of mobile phase must be dictated not only by its effect on the components of a peptide mixture but also by its effect on the reversed-phase sorbent. Reversed-phase silica-based columns may contain surface silanols that act as weak acids and are ionized above pH 3.5-4.0 [25,107]. These weak acids may interact with the basic residues of peptides chromatographed on reversed-phase columns and thus have an adverse effect on resolution, characteristically producing long retention times and peak broadening. 

The fundamentalpattern and resolution characteristics ofantennas are summarized in Fig. 17.3. Antenna response and performance is generally characterized by its far-field pattern, which is independent of range (REF). The antenna near-field pattern is a function of range and is equivalent to the Fresnel region... 

Although these aforementioned interactions obscure the important high-resolution characteristics of solid-state NMR spectra of powders such as chemical shift, these interactions could offer the information on the structure and bonding. Dipole-dipole interaction can yield information on internuclear distances and molecular geometries. CSA gives information on the coordination symmetry. Symmetry of the charge distribution around the nucleus may be derived from analysis of quadrupole interactions. Also, due to the sensitivity of the line shape of quadrupole nuclei (eg, H NMR line shape) to the molecular... 

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