A noncontact

FIG. 21-49 Application of a noncontact inkjet printing system used for coding plastic bottles and corrugated fiberboard cartons. (VIDEOJET shown, couitesy of VIDEOJET Systems International, Inc., 1500 Mittal Blvd., Wood Dale, IL 60191-1073.)... 

Electronics has, in fact, been a very fertile area for SEM application. The energy distribution of the SEs produced by a material in the SEM has been shown to shift linearly with the local potential of the surface. This phenomenon allows the SEM to be used in a noncontact way to measure voltages on the surfaces of semiconductor devices. This is accomplished using energy analysis of the SEs and by direedy measuring these energy shifts. The measurements can be made very rapidly so that circuit waveforms at panicular internal circuit nodes can be determined accurately. 

Electrical and mechanical runout of the rotor surfaces to be observed by vibration probes shall be determined and recorded. The runout shall be determined by rolling the rotor supported by V-blocks positioned at the centerhne of the bearing journals while measuring runout with a noncontacting vibration probe and a dial indieator simultane-... 

Raman spectroscopy s flexible and minimally intrusive sampling configurations reduce sample pretreatment demands. Sampling interfaces can be engineered for almost any environment, but these requirements must be clearly defined before probes are built. No probe can be made to survive all environments so there may be some design trade-offs. In a noncontact system, the laser usually comes to a focus several inches... 

Bauer et al. describe the use of a noncontact probe coupled by fiber optics to an FT-Raman system to measure the percentage of dry extractibles and styrene monomer in a styrene/butadiene latex emulsion polymerization reaction using PLS models [201]. Elizalde et al. have examined the use of Raman spectroscopy to monitor the emulsion polymerization of n-butyl acrylate with methyl methacrylate under starved, or low monomer [202], and with high soUds-content [203] conditions. In both cases, models could be built to predict multiple properties, including solids content, residual monomer, and cumulative copolymer composition. Another study compared reaction calorimetry and Raman spectroscopy for monitoring n-butyl acrylate/methyl methacrylate and for vinyl acetate/butyl acrylate, under conditions of normal and instantaneous conversion [204], Both techniques performed well for normal conversion conditions and for overall conversion estimate, but Raman spectroscopy was better at estimating free monomer concentration and instantaneous conversion rate. However, the authors also point out that in certain situations, alternative techniques such as calorimetry can be cheaper, faster, and often easier to maintain accurate models for than Raman spectroscopy, hi a subsequent article, Elizalde et al. found that updating calibration models after... 

Dielectric spectroscopy, also known as impedance spectroscopy, has been used for process analysis for some time, as it offers the ability to measure bulk physical properties of materials. It is advantageous to other spectroscopic techniques in that it is not an optical spectroscopy and is a noncontact technique, allowing for measurement without disturbing a sample or process. The penetration depth of dielectric spectroscopy can be adjusted by changing the separation between the sensor electrodes, enabling measurement through other materials to reach the substrate of interest. Because it measures the dielectric properties of materials, it can provide information not attainable from vibrational spectroscopy. 

AFM can be run under room conditions. It can be performed in either of the two forms— a contact mode and a noncontact mode. It does not require the use of electrically conductive material since (in the contact mode) the tip actually touches the surface rather than residing immediately above it, as is the case with STM. In both the contact and the noncontact mode, light is used as the sensing source rather than an applied voltage. In contact AFM, a cantilever... 

Fig. 13. Schematic of a wafer shape measured using a noncontact capacitance probe. The warp and bow are exaggerated. (Courtesy of ADE Corporation, Westwood, MA.)...

RFID technologies with the appropriate IT infrastructure help major distributors and manufacturers as well as other logistics operations such as the health care system, defense industries, and others deal with complex, global supply chains in which products and product shipments must be traced and identified in a noncontact, wireless fashion using a computer network. 

Oscillation of the crystal is due to the AC electric field applied across the crystal from metal electrodes. Typical electric fields are quite low, 10-20 V cm-1. The electrodes are deposited directly on the quartz crystal (Fig. 4.4) although, in principle, a noncontact activation of the crystal is also possible. 

Measuring the temperature of cured polyurethanes requires a special technique. Polyurethanes are a poor conductor of heat and the probe will locally heat or cool the surface of the material. Once a temperature is obtained, the probe must be quickly moved to a second and third spot to obtain the correct temperature. The use of a noncontact thermometer (such as an infrared thermometer) can eliminate this problem. The instrument must be of the correct range and resolving power. 

The best example of a noncontact reaction is the energy transfer governed by a multipole interparticle interaction. It proceeds according to the following scheme ... 

Ink-jet printing is a noncontact method the sample solution is dispensed without direct contact between the print head and the substrate. In modern ink-jet technology, a... 

Polyimides derived from 1,2,3,4-cyclobutanetetracarboxylic dianhydride and selected aromatic diamines have been found effective as photosensitive materials. These materials have applications as liquid crystals aligners, liquid crystal displays, and related liquid crystal optical elements. The fdm preparation uses a noncontact method that can reduce dust and static charge buildup and improve resolution. 

A photoinduced discharge apparatus includes a corona charging unit, an exposure system, and a noncontacting voltmeter. A grid is usually positioned between the corona wires and the sample to control the corona current. The apparatus is normally provided with a beam splitter and radiometer. The surface potentials are determined by a capacitively coupled probe and FET amplifier. The time derivative of the voltage can be obtained electronically or by numerical differentiation on a computer. When a time resolution greater than 10 ms is adequate, commercial voltmeters, for example, Monroe Electronics Isoprobe or Trek Electrostatic voltmeters, can be used. These are feedback devices, based... 

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