Warped data

This is the classic a-TR-a sequence of NMR in imaging form. The sequence form, showing how the various gradients and RF pulses are manipulated for a spin-warp data acquisition, is sketched in Figure lA. The dotted lines indicate that the phase encoding gradient is varied from one acquisition to the next. The theoretical relationship for the sequence is ... 

With disk diameters above 5.25 in., all parameters, eg, water absorption and thermal expansion, become more critical which aggravates the expansion or warp of disks. If in the future disk rotation speeds have to be increased significantly to boost data transfer rates, higher demands will be placed on warp (tilt angle) and modulus to avoid creeping (ie, irreversible elongation in radial direction). A survey of the requirement profile for the substrate material of optical disks is given in Table 5 (182,186,187,189). 

Table 9 compares the most important properties of substrate materials based on BPA-PC, PMMA, and CPO (three different products) (216,217). The future will prove if the current disadvantages of CPO against BPA-PC regarding warp, processibiUty (melt viscosity), and especially cost can be alleviated. CycHc polyolefins (CPO) and, especially cycloolefin copolymers (COC) (218) and blends of cycloolefin copolymers with suitable engineering plastics have the potential to be interesting materials for substrate disks for optical data storage. 

An example of a practical dielec trofilter which uses both of the features described, namely, sharp electrodes and dielectric field-warping filler materials, is that described in Fig. 22-34 [H. I. Hall and R. F. Brown, Lubric. Eng., 22, 488 (1966)]) It is intended for use with hydrauhc fluids, fuel oils, lubricating oils, transformer oils, lubricants, and various refineiy streams. Performance data are cited in Fig. 22-35. It must be remarked that in the opinion of Hall and Brown the action of the dielec trofilter was electrostatic and due to free charge on the particles dispersed in the hquids. It is the present authors opinion, however, that both elec trophoresis and dielectrophoresis are operative here but that the dominant mechanism is that of DEP, in wdiich neutral particles are polarized and attracted to the regions of highest field intensity. 

H.J. Ramaker, E.N.M. van Sprang, J. A. Westerhuis and A.K. Smilde, Dynamic time warping of spectroscopic batch data. Anal. Chim. Acta, 498, 133-153 (2003). 

MR is an ensemble of techniques that aims to place and orientate an approximate molecular model in the unit cell of the crystal being studied. This will provide the starting phases needed to calculate the initial electron density map from which the protein model can be built, either manually by iterative use of reconstruction with molecular graphics packages (Jones et al., 1991) followed by refinement (Murshudov et al., 1997), or automatically if diffraction data up to 2.3 Angstroms or better are available (ARP/wARP (Perrakis et al., 2001), Solve/Resolve (Terwilliger, 2003)). 

High resolution (between 1.4 and 2.0 A) Automated model building with ARP/wARP should work with most phase sets. RESOLVE, which uses a template-based rather than atom-based approach, should also perform well but may be computationally more consuming. Refinement can best be carried out with REEMAC or PHENIX using isotropic ADPs since the amount of data is no longer sufficient for an anisotropic description of atomic displacement parameters. The use of TLS (Winn et ah, 2003) is highly recommended. A use of NCS restraints should be critically evaluated and in most cases the refinement can proceed without them. Double conformations of side chains should be visible and modelled. Ordered solvent can be modelled automatically. 

The BRUKER-m.a.c.s. LabStar control and data system controls the GC/MS measurement hardware and acquires and stores measured data. It works under an IBM OS2 Warp multitasking operating system. In addition to data acquisition and real time display of data currently acquired (mass spectrum and chromatogram), it also allows for data evaluated or processed by the BRUKER DataAnalysis software. 

The weaving of the yarn was conducted on a Draper model X P loom operating at 160 picks per minute. A 115 g/ni (3.4 oz/ydZ) printdoth fabric was produced with approximately 68 ends by 70 picks. The statistical data accumulated during the weaving opera-ation of the three types of yarn treatments are presented In Table VI. The average number of breaks per hour In warp yarn for starch, fermented starch, and enzyme-degraded starch was 1.62, 1.37, and 1.45, respectively. 

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