Pulse, pulses electrical

For stand-alone or hybrid TOF mass spectrometry, the ions examined must all start from some point at the same instant. From this zero time, the ions are accelerated through a short region by applying a short pulse of electric potential of several kilovolts. The acceleration gives the ions velocities that vary in proportion to the square root of their m/z values. 

Hybrid time-of-flight (TOF) mass spectrometers make use of a TOF analyzer placed at right angles to a main ion beam. Ions are deflected from this beam by a pulsed electric fleld at right angles to the ion beam direction. The deflected ions travel down the TOF tube for analysis. Hybrid TOF mass spectrometers have many advantages arising from the combination of two techniques, neither of which alone would be as useful. 

The pusher electrode must be operated by placing very short pulses of electric potential on it. The short pulses are required to ensure that all the ions are started at the same time along the TOP analyzer, since the latter must time the flights of the ions very accurately in order to measure m/z values. 

The TOP analyzer provides the full mass spectrum of all the ions in the main ion beam at the time the pulse of electric potential was applied, m/z values being derived from the flight times of the ions along the TOP analyzer. 

After the pulsed electric field has been applied, a pulse of ions travels along a TOF analyzer placed at a right angle to the original ion beam. When the pulse is off, the ions have only their original velocities and continue into a different ion collector. 

A number of chemiluminescent reactions have been studied by producing key reactants through pulsed electric discharge, by microwave dissociation, or by observing the reactions of atoms and free radicals produced in the inner cone of a laminar flame as they diffuse into the flame s cool outer cone (182,183). These are either combination reactions or atom-transfer reactions involving transfer of chlorine (184) or oxygen atoms (181,185—187), the latter giving excited oxides. 

Pulse The regular beating of the blood in the main blood vessel, a pulse of electricity, the vibrating of a mechanical or electrical device. 

L. Avrami et al, Preliminary Studies on Pulsed Electric Field Breakdown of Lead Azide , PATR 4991 (1976) 128) D.P. Tetz, Teledyne... 

Advances in the application of pulsed electric fields for the separation and analysis of large macromolecules use of multidimensional electric fields for enhanced separation of nucleic acids... 

In the interdisciplinary field of biophysics and biotechnology, the bioeffects of electric field have received considerable interest for both fundamental studies on these interaction mechanisms and potential application. However, the effects of pulsed electric field (PEF) on secondary metabolism in plant cell cultures and fermentation processes have been unknown. Therefore, it would be very interesting to find out whether PEF could be used as a new tool for stimulating secondary metabolism in plant cell cultures for potential application to the value-added plant-specific secondary metabolite production. Furthermore, if the PEF permeabilization and elicitation are discovered in a cell culture system, the combination of... 

Chalermchat, Y, Fincan, M., and Dejmek, P, Pulsed electric field treatment for solid-hquid extraction of red beetroot pigment mathematical modelling of mass transfer, J. Food Eng., 64, 229, 2004. 

Another important property of the outer membranes of nerve and muscle cells is their susceptibility to excitation under the effect of electric action. Excitation can be brought about, for example, by an external electric current pulse. Pulses can be applied to the membrane with the aid of two microelectrodes, one residing in the extracellular fluid and the other introduced through the membrane into the cytoplasm. 

Bendicho, S., Barbosa-Canovas, G. V., and Martin, O. (2002). Milk processing by high intensity pulsed electric fields. Trends Food Sci. Technol. 13,195-204. 

Evrendilek, G. A., Dantzer, W. R., Streaker, C. B., Ratanatriwong, P., and Zhang, Q. H. (2001). Shelf-life evaluations of liquid foods treated by pilot plant pulsed electric field system. J. Food Process. Preserv. 25, 283-297. 

Sepulveda, D. R., Gongora-Nieto, M. M., Guerro, J. A., and Barbosa-Canovas, G. V. (2005). Production of extended-shelf-life milk by processing pasteurized milk with pulsed electric fields. /. Food Eng. 9, 217-223. 

Soliva-Fortuny, R. C., Balasa, A., Knorr, D., and Martin-Belloso, O. (2009). Effects of pulsed electric fields on bioactives compounds in foods A review. Trends Food Sci. Technol. 20, 544-556. 

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