Zhong-Can Ou-Yang

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The complete energy expression of a deformed single-walled carbon nanotube (SWNT) is derived in the continuum limit from the local density approximation model proposed by Lenosky et al. and shows to be content with the classic shell theory by which the Young's modulus, the Poisson ratio and the effective wall thickness of SWNTs are obtained as Y = 4.70TPa,(More)
Recent single-macromolecule observations revealed that the force/extension characteristics of single-stranded DNA (ssDNA) are closely related to solution ionic concentration and DNA sequence composition. To understand this, we studied the elastic property of ssDNA through the Monte Carlo implementation of a modified freely jointed chain (FJC), with(More)
Elastic theory of low-dimensional continua and its applications in bio-and nano-structures This review presents the elastic theory of low-dimensional (one-and two-dimensional) continua and its applications in bio-and nano-structures. First, the curve and surface theory, as the geometric representation of the low-dimensional continua , is briefly described(More)
This paper aims at a comprehensive understanding of the novel elastic property of double-stranded DNA (dsDNA) discovered very recently through single-molecule manipulation techniques. A general elastic model for double-stranded biopolymers is proposed, and a structural parameter called the folding angle straight phi is introduced to characterize their(More)
Using polymer elastic theory and known RNA free energies, we construct a Monte Carlo algorithm to simulate the single RNA folding and unfolding by mechanical force on the secondary structure level. For the constant force ensemble, we simulate the force-extension curves of the P5ab, P5abc deltaA, and P5abc molecules in equilibrium. For the constant extension(More)
Recently experiments showed that some adhesive receptor-ligand complexes increase their lifetimes when they are stretched by mechanical force, while the force increase beyond some thresholds their lifetimes decrease. Several specific chemical kinetic models have been developed to explain the intriguing transitions from the " catch-bonds " to the "(More)
The structural property of a poly( dG-dC) or poly( dA-dT) nucleotide is investigated. At low force and room temperatures, the polymer takes on compact hairpin structures. An abrupt transition from hairpin to random coil occurs at certain critical forces, its high cooperativity is related to the unfavorable formation of hairpin and other kinds of looped(More)
After a brief introduction to several variational problems in the study of shapes of thin structures, we deal with variational problems on 2-dimensional surface in 3-dimensional Euclidian space by using exterior differential forms and the moving frame method. The morphological problems of lipid bilayers and stabilities of cell membranes are also discussed.(More)
Using the continuous time Monte Carlo method, we simulated the translocation of a polynucleotide chain driven through a nanopore by an electric field. We have used two models of driven diffusion due to the electric field. The chain may have strong interaction with the pore, and depends on which end of the chain first enters the pore. Depending on this(More)