Cutting, single crystals

Fig. 9.18 Comparison of calculated time-domain spectra (NFS) and energy-domain spectra (Mossbauer absorption) for a-, b-, and c-cut single crystals of guanidinium nitroprusside. For the calculations the approximation of complete alignment of 14 parallel to the crystallographic c-axis is used. The polarisation direction of the synchrotron beam is represented by e. (Taken from [48])...

The TiC>2 samples, mounted in a helium cryostat (10-300 K), are lmm-thick (001) and (110)-cut single crystals to study the electronic response with the (THz) electric field perpendicular ( L) and parallel (//) to the c axis, respectively. Rutile is the most common and stable TiC>2 polymorph and has a tetragonal structure with a=4.6A and c=2.9A. The band gap of rutile is 2.9 eV at room temperature, increasing slightly at lower temperatures. 

Flo. 16. Induction time for the isomerization of 1-butene on cut single crystal catalyst of MoS2 (14,37). 1-Butene (25 torr) was added first, followed by the addition of H2 (75 torr) at 100 C. 

Fig. 21. Hydrogen exchange between l-butene-d0 and l-butene-d8 and their isomerization on cut single crystal catalyst of MoS2 at 100°C, where mw indicates sampling for microwave spectroscopic analysis (14,37).

Fig. 22. Selective hydrogen mixing between C2H4 and C2D4 during induction time Tor the isomerization of m-2-butene-d0, and superimposed hydrogen scrambling between C2D4 and cis-2-butene-dQ after the induction time on cut single crystal catalyst of MoS2 at 100°C (8,14).

Several other calibration methods have been suggested. Russell and Pier-marini (9) used gem-cut single crystal cubic zirconia anvil as a calibrant. The crystals were examined to 132kbar. The use of the Raman-active F2g lattice mode of diamond at 1332.5 cm-1 as an internal standard has also been suggested (Section 3.2.5, also Refs. 10,11). It has been shown to have a linear response to pressure over the range of 50 200 kbar. 

Oxygen Chemisorption.—Most studies on Pt have used polycrystalline wires, foils, or specially cut single-crystal faces. In all cases, samples are initially heavily contaminated with graphitic surface layers. Pignet, Schmidt, and Jarvis, for example, showed by AES that heating at 400 °C in 1 atm of oxygen effectively removed surface C and S and that the resulting surface was not... 

Static high pressure experiments employing diamond anvil cells (DAC) now can routinely attain pressures from the kilobar (0.1 MPa) to the multimegabar (>100 GPa) range. The pair of opposing anvils are formed from brilliant-cut single crystal diamonds with small culet... 

For SR protein crystallography two main designs for the monochromator system have been utilised to date based on either the bent oblique-cut single crystal or ( +, —) parallel double crystal system. In the next sections (sections 5.2.3 and 5.2.4) we describe their properties in detail. 

Figure 5.7 Reflection from an asymmetrically cut crystal monochromator. The width of the reflected beam is compressed relative to that of the incident beam. The asymmetrically cut single crystal when bent to the Guinier setting (figure 5.6(b)) provides a minimum 6XIX and a foreshortened focussing distance (equation (5.7)).

Bent, oblique-cut, single crystal in a high intensity small sample camera on a low emittance source The use of Bragg optics is highly effective in producing aberration-free demagnification of a source. For a typical protein crystal size of 0.3 mm,... 

A 200 pm thick, 30 mm diameter, Z-cut, single-crystal LiTaOs wafer, unpolished on both sides, was used to fabricate the pyroelectric flow sensor. The wafer was first degreased by immersing in trichloroethane, acetone, and isopropyl alcohol for 10 min each, and then it was rinsed in deionized (DI) water and blown dry with nitrogen. After cleaning, nichrome (NiCr) and gold films were sequentially deposited on the front surface of the wafer. This was done in a cryopumped electron-beam evaporator at a pressure of about 10 Pa without breaking vacuum between the NiCr and Au evaporations. The last step minimized contamination of the devices. 

A single-crystal quartz reference is used in a standard determination of second-order macroscopic susceptibilities A 0.5-mm-thick, y-cut, single crystal... 

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