Electronic feedback systems

Catalytic treatment of motor vehicle exhaust has been applied in all passenger cars in the USA since the 1975 models. The first cars with electronic feedback systems and three-way catalysts were 1979 Volvos, sold in California. Today all new gasoline cars sold in the Western world are equipped with catalytic converters. It... 

The approach described represents one more step toward the realization of a completely stand-alone single-electron junction based on nanoparticles and produced in organic matrix. Quantum dot synthesis directly on the tip of a metal stylus does not require the use of STM for localizing the particle position and requires only the use of atomically flat electrodes and a feedback system for maintaining a desirable double-barrier structure. 

Cutts, Q., A. Carbone, and K. van Haaster (2004) Using an electronic voting system to promote active reflection on coursework feedback. Proceedings of the International Conference on Computers in Education, Melbourne, Australia, November 30-December 3,2004. 

In-situ SPV measurements seem possible with minor modifications (1) the tip potential (versus the reference) is set at a value close to the rest potential of the semiconductor in darkness (this must be compatible with the electrochemical response of the tip), and (2) the tip current is quenched by adjusting the sample voltage (versus the reference) with the second feedback system. With p-type materials the method seems more obvious than with n-type specimens, since illumination promotes surface electrons. At n-type materials SPV measurements will induce corrosion since holes are driven to the interface. If absolute measurements of the SPV seem difficult, because they depend on the adjustment of the tip potential, differential measurements appear accessible to experiment. 

The process of continuous measurement and control is often referred to as a feedback system, and the cycle of measurement, comparison, and control is called a feedback loop. These ideas find wide application in biological and biomedical systems, mechanical systems, and electronics. From measuring and controlling the concentration of manganese in steel to maintaining the proper level of chlorine in a swimming pool, chemical analysis plays a central role in a broad range of systems. 

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