Ceramics Macor

The stack of platelets is encompassed by two end caps bearing the external fluidic connections. If desired, a third housing part can be introduced in between the end caps to shield the stack. As a further design modification, ceramic Macor insulating plates can be inserted between the end caps and platelet stack to prevent heat losses from the stack to the housing. 

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 4-3 Selected properties of MACOR glass-ceramic (MACOR 1992).

The sample cell (C) is made of stainless steel with sapphire windows (1) and has an insertion (2) made of ceramics (Macor,Corning) which is inert against all solvents and solutes. The cell is taken out of the autoclave for filling through inlet (3) which is closed with a thin membrane of soft plastics (4) t>y means of screw (5). The cell is then pushed into the autoclave and kept in position by screw (6). 

Figure 1. Diagram of Teflon cell (1) platinum electrode (2) glass scintillator (3) Macor ceramic disk cell bottom (H) Teflon O-ring (5) flexible elbow (see insert) (6) cell ports (six of them around cell body) (7) light pipe. Inset shows the details of the flexible elbow (8) stainless steel sphere (9) concave Teflon spacer (10) platinum wire for electrical connection across elbow (11) lock nut.

Figure 2. Diagram of electrode in adsorption position and "squeezed" position for adsorbate measurement (1) smooth, polycrystalline platinum electrode (2) polished glass scintillator detector (3) Macor ceramic disk, which forms cell bottom ( )) resin (5) electrode shaft.

Mach-Zehnder interferometer, 22 153 Mackenzie-Shuttleworth model, 23 75 Mackie line effect, 19 209, 210 Macor glass-ceramic, 22 635 Macquartite, 6 471t Macrinite, 6 707t Macrobicyclic effect, 24 39 Macrocrystalline wax, 26 214 Macrocycles, 24 35, 45 developments of, 24 36 Macrocyclic complexes, rhodium, 29 645 Macrocyclic compounds, chelating agents, 5 710, 713t... 

Figure 2.12 Exploded (left) and assembled (right) view of a toroid cavity autoclave probe for in situ investigations under high gas pressures or in supercritical fluids. Autoclave base (A) and autoclave body (P-bronze, B) thermocouple (C) coaxial heater (D) PTFE ring (E) central conductor (Cu/Be ring, F) nonmagnetic pin from male coaxial connection (G) RF feedthrough (from Rathke [28], H) base-plate (MACOR, I) fixing screws (P-bronze, J) PEEK capillary (l<) ceramic ball (Si3N4, L) PTFE seal (M).

For use over a wide temperature range, it is necessary to match the thermal expansion coefficients of electrode and insulation sheath. RRDEs of glassy carbon embedded in borosilicate glass for use up to 450° C [123] and gold sputtered on to a chromium or titanium substrate on a Macor ceramic cylinder for use up to at least 125°C [124] are examples. 

The glass plates were sandwiched between two polished alumina flats so that weights could be applied on top, and the glass surfaces would remain smooth after thermal bonding [105]. To ensure even heat distribution, the two bonding plates were sandwiched between two Macor ceramic plates [139]. 

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. 

Schelles W. and Van Grieken R. E. (1996) Direct current glow discharge mass spectrometric analysis of macor ceramic using a secondary cathode, Anal Chem 68 3570-3574. 

Baumann has also made heat flux measurements using thermographic phosphors.Wind tunnel models made of three different materials (steel, Macor glass ceramic, and Norcoat 4000 silicone elastomer), all of which had thin coatings of Y202S Eu (0.15%) applied, were monitored during blow-down tests in a hypersonic flow facility. The response time of the measurement system was typically less than 200 msec, and the values of the heat flux measurements obtained with... 

Fig. 8 A scanning electron microscope micrograph of microwave-joined MaCor and hydroxyapatite, joined at 1020°C for 20 min in a single-mode 2.45 GHz microwave cavity. (MaCor is a mica-platelet reinforced glass ceramic and HAP is a bioceramic material.) (From Ref. f Reprinted with permission of The American Ceramic Society, www. ceramics.org. Copyright 2003. All rights reserved.)...

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... 

Brittle fracture is used for shaping and machining ceramics after they have been fired. Ceramics can be modified to make them machinable this is controlled fracture and is the approach we adopt with machinable glass-ceramics such as Macor (Chapter 26). Of course, many ceramics already are machinable and can be shaped into intricate and beautiful forms as illustrated in the carved marble sculpture shown in Figure 18.1. 

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... 

The material chosen as a test material is MACOR. MACOR is a machinable glass ceramic and is a fluorine rich glass with a composition approaching trisilicic fluorphlogopite mica (KMg3AlSi30ioF2) (6). The material was acquired in a rod form. 

Machinable glass-ceramics are based on internally nucleated fluoromica crystals in glass (Beall 1971a). One commercial material has been marketed for 20 years under the trademark MACOR and has found wide application in such diverse and speciality areas as precision electrical insulators, vacuum feedthroughs, windows for microwave-type parts, samples holders for field-ion microscopes, seismograph bobbins, gamma-ray telescope frames, and... 

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