Capillary cell

Capillary cell An arrangement of porous pads sprayed with water. 

Fig. 17. Bipolar capillary cell (a) 125 fim gaps, (b) glass vessel, (o) electrical leads, (d) stack of graphite plates, (e) solution flow. (Taken from Beck and Guthke, 1969.)...

Effective diffusivities for these ions in equimolar concentration ratio and with various inert electrolytes, have been determined by several methods (see Table III). The mobility products obtained from capillary cell (stagnant diffusion) and rotating-disk measurements are in fairly good agreement. 

CC, Capillary cell (stagnant diffusion) DS, diffusion to spherical electrode ICT. from mobility measurements (International Critical Tables) LFA. laminar-flow annular cell (Leveque relation) LM, from limiting mobility at infinite dilution POL. polarographic cell RDE, rotating-disk electrode. 

Fig. 14. Integral diffusivities of Cu2 +, corrected for migration effect, as a function of true ionic strength, /r. Circles and triangles indicate values reported by Selman (S8) and Hsueh (H7), squares indicate results of Arvia el al. (A5). Diaphragm cell diffusivities according to Fenech (F3) and capillary cell diffusivities according to Hsueh (H7) are also shown. [From Selman (S8).]...

Schelle, B. Dress, P. Franke, H. Klein, K. F. Slupek, J., Physical characterization of light guide capillary cells, J. Pkys. D Appl. Pkys. 1999, 32, 3157 3163... 

For example, chemicals that enter the digestive tract must be absorbed by the cells lining the small intestine and then be transferred through the cells, where the chemical can then be absorbed by the capillary cells into the bloodstream. Chemicals that are inhaled must pass through the alveoli, the cells of the lungs, to get to the capillaries and enter the bloodstream. 

Another cell design that aids to minimize the effects of thermal diffusion is the capillary cell. Fig. 15.10c. By using capillary tubing on the vent side of the cell, a sufficiently high linear flow velocity is maintained to prevent... 

We developed an experimental procedure that can be applied to highly viscous polymer blends. In the DSM micro-extruder [6], polymers are blended in the melt, at the desired temperature and pressure, and injected into a small capillary tube which is immediately sealed with a floating plug. This capillary cell is placed in a small window autoclave and a laser beam enters the capillary cell at the lens-shaped bottom end. The intensity of the light scattered by the polymer system is recorded at two scattering angles (as a function of pressure and temperature). 

The brain capillaries are tightly joined and covered by a footlike sheath that arises from astrocytes. Thus, a drug leaving the capillaries in the brain has to traverse not only the nonporous capillary cell wall, but also the membranes of the astrocyte, in order to reach the neurons. Such a structure, frequently referred to as the blood-brain barrier, tends to limit the entry of many drugs into the brain. 

To obtain an optimal signal, the sample should fill the resonator active volume as much as possible. This dictates the sample volume and the positioning of the capillary/cell in the cavity. For example, with the Bruker high-sensitivity cavity, a tilted capillary covers a smaller fraction of the active volume and therefore reduces signal intensity. It should be noted that water absorbs microwave radiations via interacting with the electric field, thus lowering the cavity Q value and making it difficult or impossible to tune. Therefore, aqueous samples, which include almost all RNA samples, tend to be lossy with low Q values. This may restrict the size of the capillaries/cells and the sample volume. 

An ideal baseline should be completely straight without any feature. This may not be the case, especially for samples with weak signals, due to a number of reasons. The cavity, the cryostat, or the capillary/cell may have a small amount of contamination, the signal of which may be reduced or even eliminated by cleaning. In addition, system instability (temperature variations, air drift, etc.) may also yield broad features in the baseline. 

Figure 2-20 (A) Gas cell with external resonating mirrors. (B) Capillary cell for liquids. (C) Cylindrical cell for liquids. (D) KBr pellet for solid samples.

In another technique, the solution is circulated through a capillary cell by a peristaltic pump (37). If part of the circulating loop is immersed in a constant-temperature bath, it is possible to measure the spectrum over a wide temperature range. A more sophisticated technique (38) allows the measurements of redox potentials and electronic spectra as well as Raman spectra using a circulating cell. 

Capillary cell As for static cell, but use a capillary Capillary prevents spurious agitation interfering, analytically difficult... 

First, if a capillary cell is used, the X-ray beam size by default has to be small—at least in the vertical direction. So, if the experiments are conducted on a nonfocused beam line then the X-ray flux irradiating the sample is lower and this will degrade the signal/noise ratio (S/N). Typically in the pressed-wafer cell designs the size of the wafer is large to allow a large X-ray beam size to be used. 

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