Electric field-focusing effects

After a brief overview of the thermal conversion data (thermal dependence of dielectric properties, electric field focusing effects, hydrodynamics) thermodynamic aspects and athermal effects of electric fields will be examined. Next, the effects of thermal path and hot spots induced by microwave heating will be analyzed in term of kinetic effects. 

The radio frequency quadrupole (RFQ) is used to accelerate protons and heavier ions. It uses four parallel electrodes around the beam axis as shown in O Fig. 50.20. The RFQs operate at high frequencies, typically from tens to hundreds of MHz. The electrodes, which are called vanes, are placed in a cavity forming a resonant structure. The adjacent electrodes have opposite charges. From the end, the RFQ looks like an electric quadrupole. This arrangement of electric field focuses the beam in one plane and defocuses it in the other one. Since the electric field oscillates, a net focusing effect can be obtained along the length of the vanes. 

The electric axial focusing effect is only important in the first few rounds, because it is proportional to the ratio of the energy gain to the kinetic energy of the particle. The almost uniform magnetic field in the center of the magnet (field index n is close to zero) produces at the same time an especially weak axial focusing. 

In the present study, our attention has been focused on cell growth direction and its vectorial control by electric fields. The effects were investigated on a single cell with a microelectrode. The use of microelectrodes may be advantageous to focus the electric field on a cell and to emphasize the vectorial property. 

A MBER spectrometer is shown schematically in figure C1.3.1. The teclmique relies on using two inhomogeneous electric fields, the A and B fields, to focus the beam. Since the Stark effect is different for different rotational states, the A and B fields can be set up so that a particular rotational state (with a positive Stark effect) is focused onto the detector. In MBER spectroscopy, the molecular beam is irradiated with microwave or radiofrequency radiation in the... 

Klapper 1, R Hagstrom, RFine, K Sharp and B Honig 1986. Focusing of Electric Fields in tire Actir e Sit of CuZn Superoxide Dismutase Effects of Ionic Strength and Amino-Acid Substitution. Proteins Structure, Function and Genetics 1 47-59. 

This chapter is intended to provide basic understanding and application of the effect of electric field on the reactivity descriptors. Section 25.2 will focus on the definitions of reactivity descriptors used to understand the chemical reactivity, along with the local hard-soft acid-base (HSAB) semiquantitative model for calculating interaction energy. In Section 25.3, we will discuss specifically the theory behind the effects of external electric field on reactivity descriptors. Some numerical results will be presented in Section 25.4. Along with that in Section 25.5, we would like to discuss the work describing the effect of other perturbation parameters. In Section 25.6, we would present our conclusions and prospects. 

Among the recently published works, the one which showed that the cyclic structures of water clusters open up to form a linear structure above a certain threshold electric field value a was a systematic ab initio study on the effect of electric field on structure, energetics, and transition states of trimer, tetramer, and pentamer water clusters (both cyclic and acyclic) [36], Considering c/.v-butadiene as a model system, the strength and the direction of a static electric field has been used to examine the delocalization energy, the probabilities of some local electronic structures, the behavior of electron pairs, and the electronic fluctuations [37]. Another recent work performed by Rai et al. focused on the studies using the DFT and its time-dependent counterpart of effects of uniform static electric field on aromatic and aliphatic hydrocarbons [38],... 

The separation of ions according to their m/z ratios is achieved using electric and/or magnetic fields in a number of ways. The trajectories of ions moving in such fields are determined by their m/z values and these can be monitored to ascertain their mass. Double-focusing instruments use the combined effects of electric and magnetic fields to effect separation (Figure 3.19). In a typical instrument, after the ions have been accelerated away from the ion source... 

The question arises as to what effects are responsible for the generation of the very first tiny etch pits on the surface. However, this question is misleading in some respects. A flat n-type surface anodized in HF is in an unstable condition. Tiny inhomogeneities of flatness in the electrode surface, inevitably produced by the dissolution process, are amplified, because the concave areas will focus the electric field and thereby become more efficient in collection holes than flat areas. An increase in anodization bias accelerates pore initiation at flat electrodes. 

With TMS, a brief but powerful electric current is passed through a small coil held against the scalp of a conscious patient. This generates a powerful local magnetic field which passes unimpeded through the skull and induces a weaker, less focused electric current within the brain. Due to the non-invasive nature of this method, the important physiological effects of TMS are likely to be a consequence of the density of the electric current and the electric field which is induced in the cortex. It is believed that the induced electrical fields cause neuronal depolarization which changes the neurotransmitter release mechanisms. 

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