Sensors application area

Another important application area is the non-destructive defectoscopy of electronic components. Fig.2a shows an X-ray shadow image of a SMC LED. The 3-dimensional displacement of internal parts can only be visualized non-destructively in the tomographic reconstmction. Reconstructed cross sections through this LED are shown in Fig.2b. In the same way most electronic components in plastic and thin metal cases can be visualized. Even small electronic assemblies like hybrid ICs, magnetic heads, microphones, ABS-sensors can be tested by microtomograpical methods. 

Optical sensors and relay switches are used throughout the test routine for verification. For all possible problems, as well as the sequence in which they occur, the robot must recognize that there is a problem, define the problem, decide how best to resolve the problem, perform the necessary operations to overcome the problem, and enable the system to resume testing. This is an AI application area and a critical feature, mainly because the system operates unattended and measurements are taken overnight and during weekends. 

Special optical fibres have been intensively investigated during recent years because of their potential wide-range use for on-line monitoring of material properties or processes in a number of areas of human activity (environment protection, food industry, medicine etc.) Their technology can be considered an integral part of the team-work on optical fibre sensors development. Despite special optical fibres represent a unique and often indispensable tool for a variety of sensor applications, special fibre production still represents only a small fraction of the market. Probably it is because of their low consumption (in comparison with standard telecommunication fibres), the need for much more advanced know-how and lower reproducibility. 

The majority of currently deployed IR sensors operate in the near-IR. Although near-IR sensors suffer from limited selectivity and sensitivity due to the relatively unstructured broadband absorptions in this frequency range, the easy availability of waveguides and other instrumentation give this spectral range a significant advantage over the mid-IR. Main application areas involve substance identification and process control. 

Similar to IR sensors, process analysis is the prevalent application area. Due to the applicability of standard VIS instrumentation, Raman probes have been used for more than two decades65, 66. Typically, Raman probes are applied where near-IR probes fail and hence are in direct competition to mid-IR probes. 

Recent developments in microsystems technology have led to the widespread application of microfabrication techniques for the production of sensor platforms. These techniques have had a major impact on the development of so-called Lab-on-a-Chip devices. The major application areas for theses devices are biomedical diagnostics, industrial process monitoring, environmental monitoring, drug discovery, and defence. In the context of biomedical diagnostic applications, for example, such devices are intended to provide quantitative chemical or biochemical information on samples such as blood, sweat and saliva while using minimal sample volume. 

The physical and chemical properties of MgO films prepared by the sol-gel technique were the area interest of the examinations presented by Shukla75. The aim of mentioned work was to produce films with nano size particles so as to employ them for the sensor applications, as adsorption in such films increases many folds due to the increase of surface area. Infra-red spectroscopic studies indicated the presence of solvent in the precursor, which helped in decomposition to nano-particles during nucleation of the film. The MgO sol-gel films were deposited on the glass rod bend in U-shape for humidity sensor. 

Some application areas of gas sensors are described in chapter 5.3, including gas and fuel powered domestic burner control, air quality sensing, indoor detection of CO, and natural gas detection. Several further applications of gas sensors are still in the development stage, e.g. for cooking and frying control, or for controlling the self-cleaning procedure (pyrolysis) of ovens. 

Many users of reed switches for sensor applications try to make their own sensors. Often, however, they do not observe some basic precautions and preventive measures to ensure reliable operation of the switch. Below we try to cover the key areas that users and manufacturers must be aware of. 

Application areas for UV sensors in the household environment are introduced and the technological requirements and challenges of UV-sensing discussed. Different detection technologies with their strengths and weaknesses are explained. Finally, reasons that limit the use of UV sensors in household appliances are discussed and way outs are lined out. 

As noted earlier, on-line process monitoring is among the application areas that can benefit most from the use of sensors provided they can be incorporated into portable systems. Electrochemical sensors are generally more suitable for these applications, even though optical sensors can also be readily adapted for this purpose (e.g. by using LEDs or photodetectors instead of conventional photometers) at the expense of somewhat degraded spectral resolution and sensitivity. 

Optical Fibers. Pure and doped fused silica fibers have replaced copper lines in the telecommunication area. Fused silica fibers are used in laser surgery, optical sensor application, and laser welding (see Sensors). Optical-fiber-tethered weapons such as fiber-optics-guided (FOG) missiles are another potential application for fused silica (249,250) (see Fiber optics). 

Finally, SECM offers a new application area for miniaturized electrochemical and biochemical sensors. They can be used in connection with a positioning system to solve, for instance, problems of cell biology, material science, and interfacial geochemistry. Since SECM instruments are now available from different commercial sources, a much broader application in the electrochemical sensor community is expected within the next years. 

However, the key components to provide the power generating functionality are based on semiconductors. Novel materials and transistor structures based on InP, SiGe and GaN represent an area of extensive R D activities with emphasis on high power, low noise and high operation frequencies. The performance of a real device such as the phase noise of a microwave oscillator depends both on the noise properties of the transistor and on the loss tangent of the oxide material which forms the stabilising resonator. Therefore, material and device related R D activities both on semiconductors and on oxides are essential to open new horizons for microwave communication and sensor applications. 

In this chapter we review recent progress of organic transistors for sensor applications. Emphasis is put on large-area, flexible pressure sensors suitable for electronic artificial skin and for photodetectors suitable for sheet image scanners. We also describe future prospects of large-area sensors and the other issues. 

Many other important application areas of chemometrics have been the subject of reviews and are too numerous to list here. A sampling of reviews in this category illustrates the breadth and diversity of chemometrics application areas. A review of applications in smart sensors [54] describes how chemometrics is an important enabling technology for the development of smart and reliable sensor systems. A review of environmental forensics [55] describes how numerical methods are critical in the process of identifying the chemical fingerprints of complex contaminant sources in environmental systems. Often, multiple sources are present at different geographic sites. By use of appropriate chemometric methods, these mixtures of different sources can be mathematically resolved to identify them and map their temporal and spatial distributions. 

The simplest interaction, and the one most utilized for SAW sensor applications, is the response due to changes in the arealAnass density (mass/area) on the device surface. The harmonic motion of the crystal surface caused by the passing surface wave causes particles bound to the surface to be translated in an elliptical orbit in synchronism with the SAW surface displacement. The effect on wave velocity and attenuation of this interaction may be derived firom eneigy considerations. 

For AW sensor applications, grains of porous powders must be immobilized by some form of thin-film physical support layer on the device surface. This requirement is nontrivial, as it is a complex problem to create a uniform, well-bound layer of tiny, porous particles that is effectively glued to a flat surface without plugging the pores with the glue used for attachment. One class of materials that has been studied as a means to immobilize high-surface-area ains... 

Lanthanide materials with potential applications as ion exchanger, moisture sensor, fluorescence material, and ion conductor, have attracted considerable research attentions [1-2]. Synthesis of open-framework lanthanide materials is of great interest because the interspaces of three-dimensional channels would be capable of enhancing some properties of this class of compounds, such as ion conductivity and ion exchange, and widening the application area as well [3, 4]. 

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