Fiber probe

Sekoguchi, K., M. Takeishi, T. Nishiure, H. Kano, and T. Nomura, 1985 Multiple Optical Fiber Probe... 

Figure 46. Typical bed collapse curve traced by optical-fiber probe tracking instrument (solids alumina A66, 140-280 microns). (Yang, Tung, and Kwauk, 1985.)...

As the potential of optical fiber probes for pH measurements was rapidly recognized, several other articles appeared within a few years75 83. Most were reflectance-based, and Seitz reported the first fluorescent pH sensors84, 78. The article by Janata85 on whether pH optical sensors can really measure pH is another "must" in the early literature since it points to aspects hardly addressed in pH sensor work. 

Narayanaswamy R., Sevilla F., An optical fiber probe for the determination of glucose based on immobilized glucose dehydrogenase, Anal. Lett. 1988 21 1165. 

Cordek J., Wang X., Tan W., Direct immobilization of glutamate dehydrogenase on optical fiber probes for ultrasensitive glutamate detection, Anal. Chem. 1999 71 1529-1533. 

G.H. Victkers, R.M. Miller and G.M. Hieftje, Time-resolved fluorescence with an optical fiber probe, Anal. Chim. Acta, 192 (1987) 145. 

Figure 7.8, Different type of optical fiber probes, hi is the incident light source, R is the dye chamber and D is the detector location, (a) The dye is entrapped around a single optical fiber, (b) The same optical fiber is used to route the incident light and the nuorescem signal. (Additional optical components are used to isolate the sample s signal.) (c) One optica] fiber is used to carry the incident light and the second fiber is use to carry the sample signal.

The availability of low-cost laser diodes has expanded the applications of NIR dyes.(34) NIR dyes have been used in analytical applications such as fiber probes(39,79) and the detection of caustic brine.(89) However, most of the NIR dye applications have been in electrophotography for the manufacturing of office products such as laser printers and facsimiles. The wavelength of the lasers is not necessarily matched to the absorbance maxima of the dyes. Therefore, an understanding of the spectroscopic properties of NIR dyes and their ability to be chemically tuned is necessary to further expand the use of these dyes. 

Both PDA and CCD fiber-optic spectrophotometers may be combined with a fiber switch or multiplexer to access multiple probes or cells in a sequential fashion. Multiplexers are available to select from among 2, 6, 9, or even more fibers/probes. 

Figure 9.11 Spectroelectrochemical cells using a bifurcated optical fiber probe (a) mercury pool working electrode (b) reflective metal working electrode. [From Ref. 67.)...

Abstract This chapter reviews the development of optical fiber probe Raman systems and their applications in life science and pharmaceutical studies. Especially, it is focused on miniaturized Raman probes which open new era in the spectroscopy of the life forms. The chapter also introduces the important optical properties of conventional optical fibers to use for Raman probes, as well as new types of optical fiber and devices, such as hollow optical fibers and photonic crystai fibers. 

Fiber optic sensors are an alternative to thermocouples as embedded temperature distribution mapping sensors. As described in Section 2.2.7, McIntyre et al.104 developed two distinct fiber optic temperature probe technologies for fuel cell applications (free space probes and optical fiber probes). Both sensor technologies showed similar trends in fuel cell temperature and were also used to study transient conditions. 

The local gas holdup and bubble behavior were measured by a reflective optic fiber probe developed by Wang and co-workers [21,22]. It can be known whether the probe is im-merging in the gas. The rate of the time that probe immerg-ing in the gas and the total sample time is gas holdup. Gas velocity can be got by the time difference that one bubble touch two probes and the distance between two probes. Chord length can be obtained from one bubble velocity and the time that the probe stays in the bubble. Bubble size distribution is got from the probability density of the chord length based on some numerical method. The local liquid velocity in the riser was measured by a backward scattering LDA system (system 9100-8, model TSI). Details have been given by Lin et al. [23]. 

Fiber probes represent a simpler challenge from the standpoint of pure sensor development than disconnected systems, in that reagent chemistry need only to be immobilized at the tip of an optical fiber. Probes can be inserted into samples,... 

A steady-state diffuse reflectance spectroscopy instrument typically includes a broadband fight source, intermediate optics, spatially separated delivery-collection optical fiber probes,77 and a CCD-based grating spectrometer. Frequency-based approaches have also been pursued.78 Correlations between the glucose concentration and the tissue transport scattering coefficient have been observed.77,78... 

Motz JT, Hunter M, Galindo LH, Gardecki JA, Kramer JR, Dasari RR, Feld MS. Optical fiber probe for biomedical Raman spectroscopy. Applied Optics 2004, 43, 542-554. 

Munro CH, Pajcini V, Asher SA. Dielectric stack filters for ex situ and in situ UV optical-fiber probe Raman spectroscopic measurements. Applied Spectroscopy 1997, 51, 1722-1729. 

The term probe or proximal probe used in this document refers to any of die wide variety of tips used in tunneling, force, and near-field optical microscopies. That is, a metallic, semiconducting, or optical-fiber probe is positioned in close proximity to a sample for die purposes of recording images. 

As with optical spectroscopy, the Raman effect can be applied non-invasively in a wide range of environments. In contrast with infrared spectroscopy, Raman measurements do not require complicated sampling techniques. In addition, optical fiber probes can be used for bringing the laser light to the sample and transporting scattered light to the spectrometer, thus allowing remote detection of Raman spectra. 

An optic-fiber probe, consisting of two separate sets of projector and receiver fibers, is used for rapid tracking and recording of the subsiding bed surface. 

Spange (2002). A diode array spectrometer with glass fiber optics was used to measure adsorbed species through a quartz window in the bottom of the reactor after sedimentation of the particles. Tromp et al. (2003) also mentioned an optical fiber probe for such an analysis. 

Weckhuysen and coworkers (Nijhuis et al., 2003) described equipment suitable for parallel Raman and UV-vis spectroscopic measurements. Openings on the opposite sides of a furnace allowed acquisition of Raman and UV-vis spectra through optical grade windows in a tubular quartz reactor. UV-vis spectra were recorded at 823 K. Gas-phase analysis was achieved with mass spectrometry and gas chromatography. A more advanced version of the design (Nijhuis et al., 2004) accommodates four optical fiber probes, placed at 10-mm vertical spacing along the tubular reactor. The temperature that the fibers can withstand is 973 K the reported spectra characterize samples at 823 K. 

Kervinen et al. (2005) investigated a homogeneous catalytic reaction, namely, the oxidation of veratryl alcohol to its aldehyde in the liquid phase. In this case, UV-vis spectroscopy, performed by immersing a fiber probe in the reacting medium, allowed detection of changes in the Co (salen) catalyst as well as monitoring of product formation. 

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