Quartz fiber optic

Figure 4.8. Schematic representation of the pressure-jump apparatus of Davis and Gut-freund (1976). The instrument is composed of the following components A, observation cell B, hydraulic chamber C, absorbancy photomultiplier D, thermostatted base E, quartz fiber optic from light source F, quartz pressure transducer for the triggering of data collection G. hydraulic pressure line H and I, observation cell filling and emptying ports J, fluorescence emission window K, bursting disc pressure-release valve L, mechanical pressure-release valve M, trigger mechanism N, reset mechanism O, value seat and P, phosphorbronze bursting disc. (Reprinted with permission of the publisher.)...

Quartz fiber optics. These have been found to be very useful for radiation transmission. Small lenses are used so as to respect the opening angle of the fiber. This depends on the refractive index of the material, which because of optical transmission... 

With electrothermal evaporation from a tungsten filament and quartz fiber optics, detection limits are at the 50-100 pg level for many elements, except for Fe which is subjected to spectral interferences from tungsten lines. This was established from the use of different working gases and especially from experiments with the addition of H2 to the argon. In the case of coupling with graphite furnace atomization Cu, Mg and Fe can be determined in serum samples without dilution for Fe and Cu and with a 1 100 fold dilution for Mg [434]. 

The major applications of lasers are CD players, optical storage devices including CD-ROM (optical read-only memory), WORM (write once, read many times) and true optical disks (unlimited read and write). The amount of information that can be packed on a disk presently is limited to the size of the spot generated by the laser. The shorter the wavelength, the smaller the spot. Other applications include laser printers, spectroscopy, and communications. Lasers operating at 1.3 micrometers and 1.55 micrometers are used for low loss quartz fiber optic communications. AlGaAs is used for... 

Quartz fiber optics These have been found to be very useful for radiation transmission. Small lenses are used so as to respect the opening angle of the fiber. This depends on the refractive index of the material, which because of optical transmission reasons is usually quartz, and is often of the order of 30-40°. A typical illumination of a spectrometer with an optical fiber (Fig. 17) uses a lens (diameter d) for imaging the source on the fiber. Fibers or fiber beams with a diameter of D = 600 pm are often used. Then the magnification (x/D) as well as the entrance angle tga = (d/2)/a2 and the lens formula determine the / number of the lens... 

A fiber optic immunosensor (FOI) has also been reported for detection of PCBs in Aroclors [204]. The quartz fiber surface is coated with PAbs against PCBs and the competitive assay takes place using as fluorescent tracer, an analog of the analyte coupled to 2,4,5-trichlorophenoxybutyrate (TCPB) on the Ab-coated fiber. The LOD achieved is around 10 pg L L... 

Multilayer Langmuir-Blodgett films doped with a cyanine dye have been deposited on the surface of a quartz multimode optical fiber and the fluorescence properties investigated. 49 The fluorescence intensity of the films was found to be a periodic function of the number of layers due to the waveguide properties of the films. 

A reversible, direct fluoroimmunosensor for human serum albumin (HS A) measurement has been described by Bright et al.(m> Antibody Fab fragments are first immobilized on small quartz plates by hinge-region thiols, and then dansylated. The immunosensor is formed by attaching the quartz plates with bound Fab to the distal end of a bifurcated fiber-optic probe, which transmits both the excitation and emission. Binding of ffSA to the immunosensor results in a three- to five-fold enhancement of dansyl fluorescence. The sensor can be reused up to 50 times, with a detection limit of about 1.8 x 10-8 M, and a somewhat limited dynamic range. 

The absorbance spectrum of a liquid or solution can be readily measured by using quartz or sapphire cuvettes and fiber-optic probes of variable path lengths. The most suitable solvents for this purpose are those not containing 0-H, N-H and C-H groups which exhibit little or no absorption in this spectral region, such as CHCI3, CCI4 or CS2. 

The extmders were monitored using a pair of custom-made transmission probes inserted into the extruder die just downstream from the screws. Each probe consisted of a sapphire window brazed into a metal body a quartz rod behind the window piped the light to the end of the probe low-OH silica fiber-optic bundles connected the probe to the NIR analyzer, an LT Quantum 12001. Optical path lengths were typically between 0.3 and 2.0 cm. 

Stutz, J., and U. Platt, Improving Long-Path Differential Optical Absorption Spectroscopy with a Quartz-Fiber Mode Mixer, Appl. Opt., 36, 1105-1115 (1997). 

Hoffmann developed an ingenious fiber optic device that can bring light into otherwise inaccessible (e.g., underground) bodies of polluted water and photolyze organic contaminants on a Ti02 coating on the surface of the quartz optical fibers.15e... 

Hafnium tetrafluoride [15709-52-9] is one component in the cladding layer of a proposed zirconium fluoride glass optical waveguide fiber composition which is expected to have a lower intrinsic light absorption than fused quartz optical fiber (see Glass Fiber optics Fluorine COMPOUNDS, inorganic-zirconium). 

Figure 17.11 Transmission spectroelectrochemistry cell designed for use with room-temperature haloaluminate melts and other moisture-reactive, corrosive liquids, (a) Auxiliary electrode and reference electrode compartments, (b) quartz cuvette containing the RVC-OTE, (c) brass clamping screw, (d) passageway between the separator and OTE compartment, (e) fritted glass separator, (f) A1 plate, (g) lower cell body (Teflon), (h) upper cell body (Teflon). This cell is normally used inside a glove box and is optically accessed with fiber optic waveguides. [From E. H. Ward and C. L. Hussey, Anal. Chem. 59 213 (1987), with permission.]...

For both type of microwave reactors, if the reactor is not supplied with a temperature sensor or more likely accurate temperature measurment is prerequisited during an experiment, the fiber-optic temperature sensor is directly applied to the reaction mixture. In order to secure the sensor from harsh chemicals, the sensor is inserted into a capillary that in turn is inserted into the reaction mixture. In such a case, it is strongly advocated to use capillaries that are made of quartz glass and are transparent to microwave irradiation. Any capillary that is made of glass or even borosilicate glass can always slightly absorb microwave energy, in particular, while the reaction mixture does not absorb microwaves efficiently, and in turn lead to failures of fiber-optic thermometer performance. 

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