Introduction to Graphene Electronics -- A New Era of Digital Transistors and Devices

The speed of silicon-based transistors has reached an impasse in the recent decade, primarily due to scaling techniques and the short-channel effect. Conversely, graphene (a revolutionary new material possessing an atomic thickness) has been shown to exhibit a promising value for electrical conductivity. Graphene would thus appear to alleviate some of the drawbacks associated with silicon-based transistors. It is for this reason why such a material is considered one of the most prominent candidates to replace silicon within nano-scale transistors. The major crux here, is that graphene is intrinsically gapless, and yet, transistors require a band-gap pertaining to a well-defined ON/OFF logical state. Therefore, exactly as to how one would create this band-gap in graphene allotropes is an intensive area of growing research. Existing methods include nano-ribbons, bilayer and multi-layer structures, carbon nanotubes, as well as the usage of the graphene substrates. Graphene transistors can generally be classified according to two working principles. The first is that a single graphene layer, nanoribbon or carbon nanotube can act as a transistor channel, with current being transported along the horizontal axis. The second mechanism is regarded as tunneling, whether this be band-to-band on a single graphene layer, or vertically between adjacent graphene layers. The high-frequency graphene amplifier is another talking point in recent research, since it does not require a clear ON/OFF state, as with logical electronics. This paper reviews both the physical properties and manufacturing methodologies of graphene, as well as graphene-based electronic devices, transistors, and high-frequency amplifiers from past to present studies. Finally, we provide possible perspectives with regards to future developments.Comment: This is an updated version of our review article, due to be published in Contemporary Physics (Sept 2013). Included are updated references, along with a few minor corrections. (45 pages, 19 figures

The Emergence of Superconducting Systems in Anti-de Sitter Space

In this article, we investigate the mathematical relationship between a (3+1) dimensional gravity model inside Anti-de Sitter space $\rm AdS_4$, and a (2+1) dimensional superconducting system on the asymptotically flat boundary of $\rm AdS_4$ (in the absence of gravity). We consider a simple case of the Type II superconducting model (in terms of Ginzburg-Landau theory) with an external perpendicular magnetic field ${\bf H}$. An interaction potential $V(r,\psi) = \alpha(T)|\psi|^2/r^2+\chi|\psi|^2/L^2+\beta|\psi|^4/(2 r^k )$ is introduced within the Lagrangian system. This provides more flexibility within the model, when the superconducting system is close to the transition temperature $T_c$. Overall, our result demonstrates that the two Ginzburg-Landau differential equations can be directly deduced from Einstein's theory of general relativity.Comment: 10 pages, 2 figure

The relation of polyphenoloxidase in leaf extracts to the instability of cucumber mosaic and other plant viruses

RESP-492

Copper-dependent and iron-dependent inactivations of cucumber mosaic virus by polyphenols

RESP-492

Chemical Modification of the Lysine-Amino Groups of Potato Virus X

Potato virus X reacted with reagents commonly used for protein amino groups, and some of its properties were changed. 2,4,6-trinitrobenzenesulphonic acid, pyridoxal-5-phosphate and methyl picolinimidate altered its absorption spectrum; the last two altered its fluorescence spectrum, and the first two altered its electrophoretic mobility. These reagents did not necessarily inactivate the virus; preparations judged to contain two modified amino groups per protein subunit retained 50 to 100% of their initial infectivity. This supports the previous conclusion that PVX-Q, an infective product of PVX and an oxidized leaf phenol, contains modified lysine ε-amino groups

PVX-Q: an Infective Product of Potato Virus X and a Leaf o-Quinone

When potato virus X (PVX) is exposed to enzymically oxidizing chlorogenic acid, and re-isolated, some of its properties are changed. Its u.v. spectrum is modified and centrifuged pellets are coloured: its u.v. fluorescence is diminished, a longer-wave fluorescence is introduced: it produces less colour with 2,4,6-trinitrobenzene sulphonic acid, and moves faster during electrophoresis. There is, however, little or no loss of infectivity in the course of the reaction. The results suggest that PVX combines with chlorogenoquinone to produce a modified but infective virus (PVX-Q) and it is thought that this reaction may occur naturally

Polyphosphates excreted by wax-moth larvae (Galleria mellonella L. and Achroia grisella Fabr.)

RESP-386

The Purification and Properties of One of the ‘b’ Proteins from Virus-Infected Tobacco Plants

The b1 protein, produced in leaves of Nicotiana tabacum cv. Xanthi-nc following infection with tobacco mosaic virus, has been purified to homogeneity by a procedure which involves gel chromatography and absorption on to DEAE-cellulose. One gel chromatography step was sufficient when the procedure was applied to leaf extracts made in an acid buffer, whereas two were necessary with extracts made at pH 8. The final product migrates as a single protein band on electrophoresis in both acrylamide and SDS-acrylamide gels. Its mol. wt. is estimated to be 15000 by electrophoresis and 14200 by ultracentrifugation. Amino acid analysis suggests that it contains about 136 residues of which 39 are potentially acidic, 13 basic and 16 aromatic. The absorbance coefficient A 1% 280 nm is estimated to be 18.9. No evidence was found for the presence of a nucleotide component