Quartz glass window

Figure 5.23 — Flow-through ionophore-based sensor for the determination of lithium in serum. (A) Mechanism involved in the sensor response (symbol meanings as in Fig. 5.20). (B) Diffuse reflectance flow-cell (a) upper stainless steel cell body (A) silicon rubber packing (c) quartz glass window (d) Teflon spacer (0.05 mm thickness) (e) hydrophobic surface mirror (/) lower stainless steel cell body. For details, see text. (Reproduced from [90] with permission of the American Chemical Society).

A xenon lamp was used as light source that irradiated the thin falling films flowing through a quartz glass window in the reactor [317]. Thiourea in methanol was used to reduce the labile endoperoxide directly to the stable diol product. The yield of cis-2-... 

The reactor has two reaction zones and is made of a stainless steel vessel with five access ports two vertical access ports which are used for the introduction of reactant gases and the collection of powders, one horizontal access port which is composed of GaAs lens and water-cooled copper block, items 4 and 16 of Figure 3.28, allowing passage of the laser beam, and the remaining two accesses with quartz glass windows to monitor the reaction zones. A stainless steel plate with a suitable hole is placed between two reaction zones to minimise their interaction. 

Figure 1.8.1 The experimental apparatus of the transparent cell., Resistance-heated furnace 2, quartz glass window 3, quartz crucible 4, charging pipe 5, camera 6, thermocouple 7, temperature controller 8, adjustable light source...

Cold-wall type CVD set-up (1) water-cooled vacuum chamber (2), (7) quartz glass windows (3), (4) gas inlets (5) pressure gauge (6) water-cooled copper electrode (8) graphite heater (substrate) (9) graphite socket (10), (11) gas outlets. 

High-pressure-resistant quartz glass windows make it possible to survey the reaction directly in the vessel ( in situ ), using light guides for the excitation and emission light (Fig. 3). The pH and oxygen concentration in the reaction mixture can be measured by the use of fluorescent indicators. 

The usual sources of ultraviolet radiation are hydrogen or deuterium discharge lamps (the latter usually being preferred) or the mercury vapour lamp. All ultraviolet sources must be fitted with quartz or silica glass windows and none of the lamps named emits any significant amounts of radiation above 400 nm. 

The material used for the lamp window is important since it must transmit the spectral line(s) of the element being studied. Because quartz glass transmits over the full wavelength range it is suitable for all lamps. The other glasses are less expensive, and they can be used for elements whose resonance lines lie above 300 nm. 

Figure 4.4-1 Basic composition of an apparatus for matrix-isolation experiments a) Rotatable cryostat with gas-handling system, b) Sectional view in the level of the matrix support, (1) matrix support, (2) refrigerator, 4-40 K, (3) radiation shield, 77 K, (4) vacuum shroud, (5) infrared window, X KBr, y PE, z quartz glass, (6) spray-on nozzle, (7) synthetic device, e.g., Knudsen cell, (8) turbomolecular pump, p < 10 mbar, (9) to backing pump, (10) transfer line, quartz or stainless steel capillary, (11) needle valve, (12) inert gas inlet, Ne, Ar, N2,..., (13) bulb for gas mixtures, (14) capacity manometer, (15) sample, (16) to high-vacuum system.

The transition metal ion-containing films were prepared carefully by ion-exchange as described elsewhere (10-16). These films were mounted in appropriate stainless steel or pyrex glass reactors/spectroscopic cells. Both reactors, described in detail elsewhere, had infrared (KBr) or uv-vis (quartz) transmitting windows for spectroscopic studies. They were equipped with vacuum valves for evacuation and gas admission, a heating system and a temperature monitor. 

For Raman analysis, sample preparation is much easier than with IR. In fact, the source light is simply focussed onto the solid or liquid sample directly. If a cuvette is used, quartz or glass windows can be used. If a slide or surface is used, a background spectrum should be taken to remove the possibility of any interfering peaks. Glass tubes are often used and since water is a weak Raman scatterer, aqueous samples can be easily analysed. Reflectance measurements, as distinct from transmissive measurements above, can also be made and are useful for studying Aims on metal surfaces or samples on diamond surfaces. Measurements should also ideally take place in the dark to remove ambient light interferences. 

Any Ca, Mg or Zn which may be dissolved in the Ce is removed by placing the product in a crucible made of MgO, CaO, BeO or Ta, wdiich in turn is placed in a second crucible made of graphite. This assembly is placed in a quartz tube with one end closed and the other connected to a high-vacuum pump via a water-cooled brass coupling. The coupling is provided with a glass window to facilitate optical temperature measurement. The well-insulated quartz tube is placed for 30 minutes in an induction furnace heated to 1250 °C. The melt is held at this temperature for 10-15 minutes, until cessation of bubbling. 

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