Sensing applications

Technology developments are revolutionizing the spectroscopic capabilities at THz frequencies. While no one teclmique is ideal for all applications, both CW and pulsed spectrometers operating at or near the fiindamental limits imposed by quantum mechanics are now within reach. Compact, all-solid-state implementations will soon allow such spectrometers to move out of the laboratory and into a wealth of field and remote-sensing applications. From the study of the rotational motions of light molecules to the large-amplitude vibrations of... 

Chemical and Biochemical Sensors. The sensitivity of the electrical properties of conductive polymers to chemical stimuli suggests they may prove useful in a number of sensing applications. 

Vaughan, R. A., "Remote Sensing Applications in Meteorology and Climatology." Reidel, Norwell, MA, 1987. 

Enzymes are proteins that catalyze chemical reactions in living systems. Such catalysts are not only efficient but are also extremely selective. Hence, enzymes combine the recognition and amplification steps, as needed for many sensing applications. 

Zou G, Ju H (2004) Electrogenerated chemiluminescence from a CdSe nanocrystal film and its sensing application in aqueous solution. Anal Chem 76 6871-6876... 

In the early days of CHEMFET development, the expectations for successful application to a variety of biomedically important sensing applications were high. This was in part due to the fact that CHEMFET s are easily miniaturized (<2 mm surface area) and so are obvious candidates for in vivo applications. This enthusiasm has largely been tempered by the reality that although field-effect tran-... 

Substitution-inert complexes have also recently been introduced into DNA as modified-base phosphoramidites. Interest here is generally focused on photo- and redox-active metal species for use as probes for sensing applications (165) and in studies on DNA-mediated electron... 

L -Conjugated Organoboron Polymers Used in Optical and Sensing Applications... 

The electron delocalizing capability of a boron atom arising from its empty p-orbital positions it as an ideal candidate for incorporation in conjugated polymers for use in optical and sensing applications. The majority of the examples of boron-atom-containing conjugated polymers have been synthesized via the hydroboration reaction. However, other synthetic procedures have also been utilized. 

Hawthorne and co-workers have also produced a series of macrocyclic Lewis acid hosts called mercuracarborands (156, 157, and 158) (Fig. 84) with structures incorporating electron-withdrawing icosahedral carboranes and electrophilic mercury centers. They were synthesized by a kinetic halide ion template effect that afforded tetrameric cycles or cyclic trimers in the presence or absence of halide ion templates, respectively.163 These complexes, which can bind a variety of electron-rich guests, are ideal for catalytic and ion-sensing applications, as well as for the assembly of supramolecular architectures. 

Terpetschnig E, Wolfbeis OS (1998) Luminescent probes for NIR sensing applications. In Daehne S, Resch-Genger U, Wolfbeis OS (eds) Near-infrared dyes for high technology applications, NATO ASI Ser 3, vol 53. Kluwer Academic, Dordrecht (NL), pp 161-182... 

In addition, the integration of modem optical technology and electrochemical techniques for sensing applications appears to be a powerful new approach. A new type of optoelectrochemical sensor for chlorine, based on an electrochromic thin-film sensing layer placed on top of a planar waveguide, has demonstrated the applicability of this combined approach. 

Usually, when referring to infrared spectroscopy, IR absorption spectroscopy is meant. Although this is the dominant method, occasionally it can be useful for sensing applications to also use IR emission spectroscopy. 

For sensing applications, high bending losses restrict the applicability as (flexible) light pipes. Practical applications are mostly restricted to gas cells, where the hollow waveguide acts as a compact multi-reflection cell to increase the sensitivity in comparison to single-pass cells. 

Nivens D., Schiza M., Angel S., Multilayer sol-gel membranesfor optical sensing applications single layer pH and dual layer CO2 and NH3 sensors, Talanta 2002 58 543-550. 

Jitianu A., Altindag Y., Zaharescu M., Wark M., New Sn02 nano-clusters obtained by sol-gel route, structural characterization and their gas sensing applications, J. Sol-Gel Sci. Technol. 2003 26 483-488. 

Chao, C. Y. Fung, W. Guo, L. J., Polymer microring resonators for biochemical sensing applications, IEEE J. Sel. Topics Quant. Electron. 2006, 12, 134 146... 

So far, in label-free chemical sensing applications, the interaction of a WGM s evanescent component with an analyte in the ambient or adsorbed on the microresonator s surface has led to the development of two sensing methods. These are monitoring of the WGM resonance frequency shift due to the analyte s change of... 

Equation (7.1) states that the intensity of the interference signal is a periodic function of the cavity length, the refractive index, and the wavelength. For most chemical sensing applications, the interference signal needs to be processed to obtain either the absolute value or the relative change of the refractive index that... 

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