MACOR tubes

MHz) for spin decoupling and H (61 MHz) for field locking. The container for liquid samples is shown in Figure 2.5. It consists of a normal high precision 5 mm NMR tube cut to a length of 60 mm and closed with a piston and a cap made from the machinable ceramic Macor. These probes were successfully used to study solvent exchange on solvated metal ions and metal ion complexes [14, 15]. 

FIGURE 15 A Paar XRK 900 cell mounted on a STOE theta-theta goniometer. Note the carefully heated piping for the feed. The bottom figure shows the sample holder with a Macor ceramic frit and the gas feed tubing forcing the feed gas through the catalyst bed. 

Fig. 1.27. Schematics of the PACIS with flow tube reactor attached to the source nozzle, (a) magnetic valve for buffer gas (He), (b) Macor insulator, (c) electrodes (the cluster material is contained in the cathode), (d) cooling coil, (e) nozzle, (f) source holder, (g) flow tube reactor, (h) reaction gas inlet, (i) pumping chaimels...

Fig. 8 Design features of a wide bore probe head for HPNMR (400 MHz) measurements. 1 O-ring 2 probe jacket 3 thermal insulation 4 polyvinyl chloride 5 O-ring 6 O-ring 7 semi-rigid coaxial cable 8 connection to thermostat 9 titanium tube 10 lid 11 screw 12 capacitor 13 capacitor holder 14 aluminium tube 15 upper plug 16 sample tube 17 saddle coil 18 -Macor 19 TiA16V4 vessel 20 lower plug 21 lower pressure screw 22 capacitor 23 coaxial cable and 24 capacitor holder.

Figure I. Cross sectional view of the high pressure autoclave with top and bottom plug, sample tube, macor plug and sample coil.

The heart of control in an STM apparatus is the exquisite sensitivity and fine control of distances exercised by the Px, Py and Pz piezo-electric drives that control tip motion. These drives are in the form of bars, tubes or bimorphs all comprised of piezo-electric ceramics in contact with Macor. A piezo-electricbar changes in length, A /p, as a function of the potential difference. Up, applied between two opposing bar electrodes according to... 

The cell housings were machined from MACOR (machinable ceramic) blocks and type 316 stainless steel bar stock. The housings were 3" diameter and 1" deep cylinders. Gas flow chaimels were machined into the large surface faces with dimensions of 0.3 cm by 0.3 cm. Gas flow tubes were connected to supply process and sweep gases to the cell. Once the electrode and membrane materials... 

The NPL (Figure 11.12) is based on the trap described by Schrama et al. [32] The outer electrodes (very fine hollow tubes of tantalum of 1 mm inner diameter and 2 mm outer diameter) are grounded, but they can receive a small DC potential. The inner electrodes, also in tantalum, are ca 0.5 mm diameter and separated from the outer electrodes by 0.56 mm. The amplitude of the RF potential is 260 Vp p at a frequency of 17.8 MHz, resulting in secular frequencies for strontium ion of 1.8 MHz (radial) and 3.0 MHz (axial). The electrodes are isolated from each other with a ceramic tube and the trap is mounted on a structure of machinable macor. Two compensation... 

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