Quartz optically transparent

Cera.micA.bla.tors, Several types of subliming or melting ceramic ablators have been used or considered for use in dielectric appHcations particularly with quartz or boron nitride [10043-11 -5] fiber reinforcements to form a nonconductive char. Fused siHca is available in both nonporous (optically transparent) and porous (sHp cast) forms. Ford Aerospace manufactures a 3D siHca-fiber-reinforced composite densified with coUoidal siHca (37). The material, designated AS-3DX, demonstrates improved mechanical toughness compared to monolithic ceramics. Other dielectric ceramic composites have been used with performance improvements over monolithic ceramics (see COMPOSITE MATERIALS, CERAMIC MATRIX). 

Due to the above requirements, typical optically-transparent materials, such as oxides (glass, quartz, alumina, zirconium oxide etc.) and halides (sodium chloride, lithium fluoride, calcium fluoride, potassium bromide, cesium bromide etc.) are usually unsuitable for use with fluoride melts. Therefore, no standard procedure exists at present for the spectral investigation of fluoride melts, and an original apparatus must be created especially for each particular case. 

What material is the sample tube made of Just like a cuvette in a UV-visible spectrometer has to be optically transparent, the EPR sample tube must be transparent for the magnetic component of microwaves. High-quality quartz is the preferred construction material low-quality quartz and especially any type of glass will not... 

J. Stotter, J. Zak, Z. Behier, Y. Show, G.M. Swain, Optical and electrochemical properties of optically transparent, boron-doped diamond thin films deposited on quartz, Anal. Chem., vol. 74, p.5924, 2002. 

In a typical spectroelectrochemical measurement, an optically transparent electrode (OTE) is used and the UV/vis absorption spectrum (or absorbance) of the substance participating in the reaction is measured. Various types of OTE exist, for example (i) a plate (glass, quartz or plastic) coated either with an optically transparent vapor-deposited metal (Pt or Au) film or with an optically transparent conductive tin oxide film (Fig. 5.26), and (ii) a fine micromesh (40-800 wires/cm) of electrically conductive material (Pt or Au). The electrochemical cell may be either a thin-layer cell with a solution-layer thickness of less than 0.2 mm (Fig. 9.2(a)) or a cell with a solution layer of conventional thickness ( 1 cm, Fig. 9.2(b)). The advantage of the thin-layer cell is that the electrolysis is complete within a short time ( 30 s). On the other hand, the cell with conventional solution thickness has the advantage that mass transport in the solution near the electrode surface can be treated mathematically by the theory of semi-infinite linear diffusion. 

The development of electrodes that exhibit optical transparency has enabled spectral observations to be made directly through the electrode simultaneously with electrochemical perturbations [19-21]. These electrodes typically consist of a very thin film of conductive material such as Pt, Au, carbon, or a semiconductor such as doped tin oxide that is deposited on a glass or quartz substrate. Miniature metal screens, minigrid electrodes in which the presence of very small holes (6-40 fim) lends transparency, have also been used. Optically transparent electrodes (OTE) and the cells that incorporate them are discussed in Chapters 9 and 11. 

Figure 9.9 Assembly of sandwich-type optically transparent thin-layer electrochemical cell, a, Glass or quartz plates b, adhesive Teflon tape spacers c, minigrid working electrode d, metal thin-film working electrode, which may be used in place of (c) e, platinum wire auxiliary electrode f, silver-silver chloride reference electrode g, sample solution h, sample cup. [Adapted with permission from T.P. DeAngelis and W.R. Heineman, J. Chem. Educ. 53 594 (1976), Copyright 1976 American Chemical Society.]...

Delta Technologies 13960 N. 47th St. Stillwater, MN 55802-1234 Indium oxide optically transparent electrodes on glass and quartz... 

Regarding the UV assay, excessive absorption may be encountered in certain cases. For example, the Good buffers PIPES and HEPES absorb substantially at 234 nm. The optional use of a 9-mm optically transparent quartz spacer inserted into a 1-cm cuvette gives a 10-fold advantage with solutions of high UV absorbance. The spacer also serves as a convenient mixer, whereas mixing is difficult with specialized 1-mm cuvettes. 

Imaging of IEF separation has been carried out. For instance, IEF of EGFP was achieved in a PMMA chip sealed with PDMS. Observation of fluorescence was achieved through the optically transparent PDMS layer [177]. In another report, IEF of pi markers was demonstrated on a quartz chip using whole-column UV (280 nm) absorption imaging [1041]. 

Optically transparent electrode — (OTE), the electrode that is transparent to UV-visible light. Such an electrode is very useful to couple electrochemical and spectroscopic characterization of systems (- spectroelectro-chemistry). Usually the electrodes feature thin films of metals (Au, Pt) or semiconductors (In203, SnCb) deposited on transparent substrate (glass, quartz, plastic). Alternatively, they are in a form of fine wire mesh minigrids. OTE are usually used to obtain dependencies of spectra (or absorbance at given wavelengths) on applied potentials. When the -> diffusion layer is limited to a thin layer (i.e., by placing another, properly spaced, transparent substrate parallel to the OTE), bulk electrolysis can be completed in a few seconds and, for -> reversible or - quasireversible systems, equilibrium is reached for the whole solution with the electrode potential. Such OTEs are called optically transparent thin-layer electrodes or OTTLE s. 

Finally, optically transparent electrodes comprised of Sn02 or ln203 thin films on glass, quartz, or plastic are widely used to study electrochemical reactions under illumination in solution. Spectral studies of reactants, intermediates, or products can be also performed to gain some molecular insight into electrode kinetics. 

The working electrode should be derived from a material optically transparent to neutrons (e.g., quartz, silicon, sapphire). 

Attempts to study the system =SiOSiCH=CH2 + Speier catalyst + hydride silica by electron spectroscopy failed for the impossibility to carry out experiments on hydridesi-lane in cells of optically transparent quartz. However, the IR spectroscopy data about the possibility of coordinating the Speier catalyst on the silica surface with vinyl groups and the results obtained when studying the mechanism of solid-phase catalytic hydrosilylation on silica surface allow us to suggest the following schemes of the catalytic hydrosilylation with the participation of vinyl-containing silica ... 

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