Scanning capabilities

Manual ultrasonic testing offers the advantages of low equipment cost combined with the flexibility of the human operator to provide good access and complex scanning capability. However, a total reliance on the capabilities of the ultrasonic technician to visualise the physical situation leads to a number of drawbacks, including lack of accuracy and consistency of defect size and location measurements, lack of verification that the required scan coverage has been fully achieved, and lack of consistency in flaw classification. A further disadvantage is that the ultrasonic data is not permanently recorded there is therefore no opportunity for the data to be re-examined at a later date if required. 

With the same scanning capability, it is much faster and often more useful to simply scan one line on a sample. The data is again output to a color CRT, but it is presented as the modulation of the y-amplitude, which is determined by the intensity of the X-ray signal production ftom the ROI of the element of interest. As the probe scans along the line, the CRT plots a graph of the elemental counting rates versus distance. Here again, it is usually possible to plot the data from many ele-... 

Another basic approach of CL analysis methods is that of the CL spectroscopy system (having no electron-beam scanning capability), which essentially consists of a high-vacuum chamber with optical ports and a port for an electron gun. Such a system is a relatively simple but powerful tool for the analysis of ion implantation-induced damage, depth distribution of defects, and interfaces in semiconductors. ... 

The advantage of the ToF instrument, in addition to its simplicity, is its fast scanning capability and for this reason it is increasingly being encountered in LC-MS instrumentation, particularly when fast analysis or high chromatographic resolution is involved. 

Sufficiently rapid scanning capability (100 ms per scanning unit)... 

The main advantages of plasma-source mass spectrometry (PS-MS) over other analytical techniques, such as PS-AES and ETAAS, are the possibilities of quantitative isotope determination and isotope dilution analysis the rapid spectral scanning capability of the mass spectrometer and semiquantitative determinations to within a factor of two or three. Several labelling methods are used for the quantification of analytes present in complex mixtures. In these methods, the sample is spiked... 

What problem exists if you want to use a single-beam instrument for precise work, even if it has a rapid scanning capability ... 

Both of the above examples illustrate that the sensitivity of the MDF method, in general, is comparable to PIS analysis and better than NLS methods (Figs 6.9 and 6.10). The sensitivity of the MDF method is attributed at least in part to the full-scan capability of high-resolution mass spectrometers such as the Q-TOF and LTQ-FTICR, which could be several times more sensitive than full-scan analysis by a triple-quadrupole mass spectrometer (Kostiainen et al., 2003). 

A calibration curve is prepared, using absorbance versus concentration plot, so that the concentration of the unknown component can be determined. But quantitative analysis for a complex system like vulcanised rubber or a blend of two or three components, is not possible. The use of computers with the FTIR spectrometer, increases the rapid scanning capability, data processing for analysis of chemical or physical structural changes in polymers as a function of time over the entire mid-IR frequency. 

Stop-flow, or fraction collection, also could be used to identify the presence of naphthalene in the second eluting fraction, but only at a considerable sacrifice in time relative to the rapid scanning capability of the OMA. However, as the complexity of a chromatographic separation increases, these approaches become impractical in terms of the time required to spectrally determine the peak purity of each fraction. 

In principle, it is also possible to use the scanning capability of Ql, using the TOF part only as a total ion current detector. However, this scan mode is not used, as all the above-mentioned advantages of using the TOF analyser are lost. 

Le Blanc, j. C., Hager, ).W., Ilisiu,A. M., Hunter, C Zhong, F., Chu, I. (2003). Unique scanning capabilities of a new hybrid linear ion trap mass spectrometer (Q TRAP) used for high sensitivity proteomics applications. Proteomics 3, 859-869. 

Options for multichannel LC-CD detection do exist.f " Stopped-flow accessories for commercial instruments are available that allow part of an eluted fraction to be taken off-line into a microcell placed in the regular sample compartment where data are measured in the normal way. The method still requires rapid scanning capabilities. Repeated injections and multiple scans can be averaged to improve the quality of the signal. A major deterrent to the progress in the early development of HPLC-CD detection was the lack of a dedicated instrument at a reasonable cost, the only option being a fully equipped CD instrument. 

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