Vertical spatial resolution

Another important application of hyphenated NMR methods is to provide insights into processes that affect the separation. Eor example, online NMR detection of the water chemical shift was used to noninvasively probe intracapillary temperatures in CE separations with subsecond temporal resolution and spatial resolution on the order of 1 mm [111]. Lacey et al. [112] followed up this report with a second NMR study using a novel 2-turn vertical solenoidal coil to measure temperature increases of more than 50 C in a chromatographic frit of the type used in CEC. Insights into the mechanisms underlying cITP have also been investigated utilizing online NMR... 

Melendres and Hahn [173] have extended the vertical spatial resolution of in situ infrared spectroscopy by employing synchrotron radiation in the far-infrared region of the spectrum, (synchrotron far infrared spectroscopy, SFIRS), to study metal-adsorbate bonds. The authors exploited the Kretschmann configuration to improve the sensitivity of the technique, and studied the adsorption of Cl and Br at the thin Au film working electrode. They observed bands near 263 and 187 cm for the Au—Cl and Au—Br stretches, respectively, in good agreement with the SERS data of Gao and Weaver [174]. 

Conventional Raman spectroscopy has a poor spatial resolution as the laser spot is normally ca. 0.5 mm. However, with the introduction of a Raman microscope, a spatial resolution as high as the diffraction limit is attainable [41, 42]. Recently, with the further development of the Raman microscope into the confocal microprobe Raman instrument, three-dimensional resolution is achievable. The quite high vertical spatial resolution ensures elimination of the signal from the bulk solution. This is certainly a great help for detecting relatively weak surface Raman signals from weak-SERS or non-SERS active electrodes. 

The thickness of the water layer over the electrode surface can also affect the vertical spatial resolution of the confocal system. For example, with smaller pinhole size (300 pm), the spatial resolution is about 17 pm and 19 pm, without and with the solution layer, while when the size is about 600 pm, the spatial resolution amounts to 21 and 53 pm for the surface without... 

It is a definition of the horizontal/vertical spatial frequency requirement of resolution (MTF) whose nominal value is dependent on the evaluation window size. 

Regardless of the model used there is a single average concentration of chemical in the soil defined as the total chemical quantity in the soil, M mol, divided by the soil volume, that is, MIV mol m . The average fugacity is MI(VZ). The models differ in their characterization of vertical spatial differences in concentration or fugacity. An obvious approach is to apply the simplest model first then increase the resolution, and demands for parameter values in the light of experience. 

A schematic representation of how the double-phase encoded DEPT pulse sequence achieves spatial and spectral resolution within the fixed bed of ion-exchange resin is shown in Fig. 45. Typical data acquired in this experiment are shown in Fig. 46. The data were recorded from a vertical section through the center of the bed. The direction of superficial flow was from the bottom to the top of the bed. The spectra shown were recorded at regular intervals along the length of the bed, with a spatial separation of approximately 2.5 mm. With reference to Fig. 46, the... 

The measurement system sensitivity threshold does not exceed 1 ppb. The time constant is determined by the electrochemical cell inertia and ranges 30 s, which corresponds to a 4-5-km and less than 300-m spatial resolution over the horizontal and vertical, respectively, for measurements during the ascent and descent of the aircraft. Atmospheric ozone concentration can be measured in-situ within the range of 0 - 4E+12 cm 3, with an accuracy not worse than 5 %. 

Because a 2-D photon-counting detector was not available at the time of construction of the demonstrator, the detector was realized as a single 1-D vertical detector column based on scintillator crystals and photomultipliers, which can be rotated around the focus point, thereby acquiring one projection. Spatial resolution was ensured by a collimator made of thin tungsten lamellae placed in front of the detector. 

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