Electrical gating

Because of the small volumes encountered in CE, implementing CE as a second dimension is difficult if a valve is used. More efficient, lower volume unions have been utilized in a number of cases. The main types of these interfaces include optical gating and flow gating, which are discussed below. Electrical gating is described in detail in Chapter 15. Fraction collection is also used, as discussed in Chapter 16, although this takes longer and is a less efficient method than the other comprehensive 2D schemes. Chip-based separation systems typically use some form of electrical gating and these systems will be discussed below. 

The use of electrically-gated solute injection into the electrophoresis system simplifies the chip design as electrical connections are easy to implement as compared to the microfluidics part of the chip. Voltage waveform manipulation via hardware and software are relatively easy to control and implement. 

Observation of Electrical Gating by ssDNA Upon Binding to Carbon Nanotube... 

Figure 1.1 Control of the graphene plas-mon resonance frequency by electrical gating and microribbon widths, (a) AFM (atomic force microscopy) images of graphene microribbons with widths of 1, 2, and 4 pm. Color bar of the height is shown on the...

The first concrete proposal for a NMR scalable quantum computer was made by Kane in 1998 [32], He showed that an array of atoms (nuclear spin 1/2) embedded in a Silicon lattice, with the hyperfine field and interaction between nuclei controlled by electric gates, could work as a scalable NMR quantum computer. Difficulties with Kane original approach were raised by Koiller and co-workers [33], Afterwards, Skinner, Davenport and Kane [34] proposed an alternative scheme in which such difficulties could be circumvented. 

Now, in order to this Si-based quantum computer work, it is necessary to control the NMR frequencies of individual P nuclei, as well as the interaction between qubit pairs. This is done by controlling the electron density in the host lattice, through electrical gates of two types the A-type and the 7-type (Figure 7.1). To understand this idea, it is necessary to remind that nucleus-nucleus interaction can be mediated by electrons, according to ... 

Suppose that right above each P nucleus position an electric gate of type A is deposited. The electronic density around each nucleus can be modified by a positive bias... 

Figure 7.1 Kane s scheme for a quantum computer based in NMR of a solid-state sample. An array of P is inserted in a silicon lattice. Electrical gates of type A control the value of the local hyperfine field, whereas gates of type J control two-qubit interactions. On the right is the estimated NMR resonance shift due to biasing of A-type gates. Adapted with permission from [1].

Ehrenstein, G. and Lecar, H., 1977. Electrically gated ionic channels in lipid bilayers. Quart. Rev. Biophys. 10 1. 

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