12,770 research outputs found
Three-Dimensional Topological Insulator in a Magnetic Field: Chiral Side Surface States and Quantized Hall Conductance
Low energy excitation of surface states of a three-dimensional topological
insulator (3DTI) can be described by Dirac fermions. By using a tight-binding
model, the transport properties of the surface states in a uniform magnetic
field is investigated. It is found that chiral surface states parallel to the
magnetic field are responsible to the quantized Hall (QH) conductance
multiplied by the number of Dirac cones. Due to the
two-dimension (2D) nature of the surface states, the robustness of the QH
conductance against impurity scattering is determined by the oddness and
evenness of the Dirac cone number. An experimental setup for transport
measurement is proposed
Applications of graph theory in protein structure identification
There is a growing interest in the identification of proteins on the proteome wide scale. Among different kinds of protein structure identification methods, graph-theoretic methods are very sharp ones. Due to their lower costs, higher effectiveness and many other advantages, they have drawn more and more researchers’ attention nowadays. Specifically, graph-theoretic methods have been widely used in homology identification, side-chain cluster identification, peptide sequencing and so on. This paper reviews several methods in solving protein structure identification problems using graph theory. We mainly introduce classical methods and mathematical models including homology modeling based on clique finding, identification of side-chain clusters in protein structures upon graph spectrum, and de novo peptide sequencing via tandem mass spectrometry using the spectrum graph model. In addition, concluding remarks and future priorities of each method are given
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