Probe ringing

A series of additional alterations of the graphite tube atomizer intended to improve performance (e.g. the cup and cup cuvette atomizer, boat and microboat platforms, carbon rods, graphite probes, ring chambers and surface atomizers) have also been reported [23]. Interested readers are referred to specific sources [2-7] for more details. 

Figure 8.9(a) shows the pulse sequence used to obtain the deuteron exchange powder pattern [59]. The sequence differs from the spin 1/2 version (chapter 6) owing to spin 1 dynamics of the deuteron and the need for quadrupole echo detection to overcome probe ringing. The first two pulses, which bracket the evolution period, provide frequency selection of individual quadrupole splittings. As with the spin 1/2 experiment, in-phase and out-of-phase pulse pairs select the sine and cosine components of the evolving magnetization to yield quadrature detection in the FI dimension. One can use either the hyper-... 

When the spectral width of the CT is too large to apply spinning-based techniques, the Hahn-echo or quadrupolar-echo sequence can be used to acquire the static spectrum to minimize the distortion of the line-shape owing to the probe ringing. The stationary spectra also contain information about the CSA. If the quadrupolar and the CS interactions both contribute to the line-shape, both the EFG and the CS tensors may be determined. 

Bearing elements made of bearing steel were subject to studies. External ring-type elements with an internal race of 20 mm diameter and 12 mm height (Fig.4) were subject to tests using the contact probe and internal volumetric ones. Results of tests are given in Table 2. 

The main component of the holder is the specially bended tube which allows the introduction of the whale probe" through a 10 mm hole in the housing ring of the engine. Then the whale probe" is easily positioned to the foot of one of the blades. After the inspection of the first blade root, the engine is rotated several degrees to allow the inspection of the next blade. 

The binding behaviour of benzene can be extrapolated to many other aromatic compounds such as naphthalene and benzene derivativesInterestingly, a large number of probe molecules contain aromatic rings and many of them will prefer the outer regions of micelles, whereas in bilayer systems, the same molecules prefer the interior of the aggregate ". Qearly these probes cannot be used to determine polarity of the micellar interior or the extent of water penetration therein . 

These reactions are believed to proceed through a complex of the alkene with a singlet excited state of the aromatic compound (an exciplex). The alkene and aromatic ring are presumed to be oriented in such a manner that the alkene n system reacts with p orbitals on 1,3-carbons of the aromatic. The structure of the excited-state species has been probed in more detail using CAS-SCF ab initio calculations. ... 

Before equations such as Eqs. 6, 7 and 8 can be used, values for the surface energies have to be obtained. While surface energies of liquids may be measured relatively easily by methods such as the du Nouy ring and Wilhelmy plate, those of solids present more problems. Three approaches will be briefly described. Two involve probing the solid surface with a liquid or a gas, the third relies on very sensitive measurement of the force required to separate two surfaces of defined geometry. All involve applying judicious assumptions to the experimental results. 

The Se NMR chemical shifts of Se-N compounds cover a range of >1500 ppm and the value of the shift is characteristic of the local environment of the selenium atom. As a result, Se NMR spectra can be used to analyse the composition of a complex mixture of Se-N compounds. For example, Se NMR provides a convenient probe for analyzing the decomposition of selenium(IV) diimides RN=Se=NR e.g., R = Bu). By this method it was shown that the major decomposition products are the six-membered ring (SeN Bujs, the five-membered ring Sc3(N Bu)2 and fifteen-membered ring Sc9(N Bu)6 (Figure 3.2 and Section 6.3). 

Gassman, P.G. Fentiman Jr., A.F. J. Am. Chem. Soc., 1969, 91, 1545 1970, 92, 2549. For a discussion of the use of the tool of increasing electron demand to probe neighboring-group activity by double bonds, sigma bonds, and aryl rings, see Lambert, J.B. Mark,... 

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