Relaxation application window

When ID WIN-NMR or 2D WIN-NMR is first started, the appropriate maximized application or main display window ID WINNMR [Spectrum] and 2D WIN-NMR respectively appears on screen. Whereas 2D WIN-NMR has only one application window, ID WIN-NMR has three additional application windows. These four application windows (Spectrum, Preview, Relaxation and Text) may be displayed altogether (Multi Document Interface, MDI) on the screen by clicking the MDI window button, or may be displayed pairwise according to your needs by clicking one of the pairs offered in the Window pull-down menu. The active application window is indicated by the highlighted title bar (Fig. 4.3). 

If you have installed MAPI (mail application interface) software on your PC, you may exploit the MS-WINDOWS mailslot-function to e-mail NMR data directly to and from your PC. The full version of ID-WIN-NMR allows you to export/irnport FlDs, spectra, tables, text-files, relaxation data and metafiles to/from other users of (the full version of) ID WIN-NMR. Both JCAMP-DX5 and Bruker specific binary format are supported. Compared to the procedure outlined in section 2.6.5 this is an even more convenient way for exporting/importing NMR data via Internet. For further details refer to the ID WIN-NMR manual [2.1] or contact your Bruker/Spectrospin representative. 

Figure 6.13. Application of the TSC technique in PMMA. Sample thickness / = 1mm, p = 1 MV/m, Tp = 100 °C, fp = 1 h, q = 5 °C7min, vacuum cell, silver electrodes provided by vacuum evaporation (Kalogeras and Vassilikou-Dova, unpublished results). Dielectric evidence for the 5 relaxation is limited even in cases where the temperature window is extended below -225 °C. Nonetheless, this mechanism can be resolved using other techniques [e.g., fluorescence emission see de Dens et al. (2004)].

To conduct proton conductivity measurements, Buchi et al. [3] designed a current interruption device that used an auxiliary current pulse method and an instrument for generating fast current pulses (i.e. currents > 10 A), and determined the time resolution for the appropriate required voltage acquisition by considering the relaxation processes in the membrane of a PEM fuel cell [3]. They estimated that the dielectric relaxation time, or the time constant for the spontaneous discharge of the double-layer capacitor, t, is about 1.4 x 10 ° s. They found that the potential of a dielectric relaxation process decreased to <1% of the initial value after 4.6r (6.4 x 10 s) and that the ohmic losses almost vanished about half a nanosecond after the current changes. Because there is presently no theory about the fastest electrochemical relaxation processes in PEM fuel cells, the authors assumed a conservative limit of 10 s, based on observations of water electrolysis membranes. They concluded that the time window for accurate current interruption measurements on a membrane is between 0.5 and 10 ns. Another typical application of the current interruption method was demonstrated by Mennola et al. [1], who used a PEM fuel cell stack and identified a poorly performing individual cell in the stack. 

An important application of the Lipari-Szabo order parameters derived from relaxation studies is to estimate the conformational entropy. Genheden and co-workers discussed the issue of conformational entropy and order parameters using long MD simulations for several proteins as a starting point. They found that the order parameters and conformational entropies calculated over 10-100 ns windows were typically well-behaved on a per-residue level, while the total conformational entropy evaluated as the sum over residues, was more difficult to estimate. Kasinath et al. probed the microscopic origin of the link between conformational dynamics and conformational entropy using MD simulations for a number of proteins. They demonstrated that the motions of methyl-bearing side chains were sufficiently coupled to those of other side chains to he excellent reporters of the side chain conformational entropy. Marsh proposed the use of relative accessible surface area in monomeric proteins as an indicator of conformational entropy/flexibility. 

The total proton frequency range that can be probed by NMR spin-lattice relaxation techniques is 10 Hz < v < lO Hz. For the present application, deuteron resonance selectively applied to perdeuterated polymers confined to the pores is superior to proton resonance which, unlike the situation in field-gradient experiments, is affected by signals from the matrix and flip-flop spin diffusion across the matrix. The deuteron fi equency range is shifted by a factor of 0.15 to lower frequencies. This frequency window largely matches the time scale of chain modes of polymers with medium molecular masses. 

SANS provides a unique tool to explore stmctural details of polymeric systems and allows kinetic studies with a resolution of a few seconds or less. Phenomena observed in polymer blends allow molecular interactions to be assessed as well as proof of theoretical predictions of static and kinetic properties of, respectively, critical phenomena and phase transition (Sections 2.11.3.2 and 2.11.3.3). Quenched SANS allows the evolution of anisotropic scattering patterns after application of sudden strain thereby extending the effeaive time window for the observation of polymer relaxation and their hierarchy in systems with more complicated architeaures from spin echo toward macroscopic times using time-temperature scaling (Section 2.11.3.4). 

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