Insertion devices time structure

The ultra small-angle X-ray scattering (USAXS) extends the accessible structure towards the micrometer range. Time-resolved measurements require a synchrotron beam that is intensified by an insertion device (Sect. 4.2.2). 

Measurements using extended x-ray absorption fine-structure (EXAFS) spectroscopy were made on the insertion-device beam line of the Materials Research Collaborative Access Team (MRCAT) at the Advanced Photon Source, Argonne National Laboratory. Measurements were made in transmission mode with ionization chambers optimized for the maximum current with linear response ( 10 photons detected/sec). A cryogenically cooled double-crystal Si (111) monochromator with resolution (AE) better than 2.5 eV at 11.564 keV (Pt L3 edge) was used in conjunction with a Rh-coated mirror to minimize the presence of harmonics [9]. The integration time per data point was 1-3 sec, and three scans were obtained for each processing condition. 

Time-resolved measurements can be made at storage rings with high flux insertion devices that use a quick-scanning mode of operation of the monochromator [574]. In a reported study, products of Mo corrosion in KOH solution could be identified and quantified [578]. Application of time-resolved dispersive high-energy X-ray absorption fine structure (DXAFS) measurements on platinum nanoparticles in a fuel electrode have been described [575]. Results indicate severe surface reconstruction of the nanoparticle surface, showing at least three types of Pt-0 bonds (adsorbed OH, adsorbed atomic O and amorphous PtOx) under oxidative conditions. 

The time structure of insertion devices depends on the value of K. If T is the time for an electron to span a wiggler period, then this is equal to the time between successive radiation peaks ... 

The spectral and time structure properties of insertion devices carry over to FELs in which they play a part. 

Mesh or spiral brush inserts were used by Megerlin et al. [182] to enhance turbulent heat transfer in short channels subjected to high heat flux. The largest recorded improvements in turbulent heat transfer coefficients were obtained—up to 8.5 times however, the pressure drop was up to 2800 times larger. In general, it appears that these displaced enhancement devices are useful in very few practical turbulent situations, for reasons of pressure drop, plugging or fouling, and structural considerations. 

Design considerations for vascular access devices include ease of handling, insertion, and use minimal thrombotic and other biocompatibility-related complications stmctural and operational reliability over time and optimization for application-specific performance issues (Canaud et al., 2000). Three different catheter tips are shown in Fig. 20.10 to illustrate these variations in design and structure. Because of the distinct characteristics of the different treatments and agents deployed through catheters, it is not practical to provide specific values for flow rates, pressure drops, viscosities, and other important transport properties. 

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