In this paper, molecular orientation behavior of polymethylene chains was investigated on the basis of considering long\|distance interactions by using the enumeration calculation method and the rotational isomeric st...In this paper, molecular orientation behavior of polymethylene chains was investigated on the basis of considering long\|distance interactions by using the enumeration calculation method and the rotational isomeric state(RIS) model. The chain lengths are from \%N\%=12 to \%N=\%24, and the Lennord\|Jennes potential was adopted in the non\|local interaction calculations. The molecular orientation function(Legendre polynomial) may be well expressed as\$\$<P\-2(ζ)>/(λ\+2-λ\+\{-1\})=a(λ\+2-λ\+\{-1\})+b\$\$here\% a\% and\% b\% only depend on the chain length, and decrease with the increase of chain length, especially for \%b\%. In the meantime, we also calculate the Helmholtz free energy change in the process of tensile deformation. Comparisons with Gaussian chains are made, and our results are close to those obtained from the Roe and Krigbaum theory.展开更多
Dynamics of protein-like chains are investigated by using Monte Carlo simulation method based on the modified orientation-dependent monomer-monomer interactions model (ODI). The diffusion coefficients for different ch...Dynamics of protein-like chains are investigated by using Monte Carlo simulation method based on the modified orientation-dependent monomer-monomer interactions model (ODI). The diffusion coefficients for different chain length are calculated,and some comparisons with self-avoiding chains are also made. There exists a relationship between the diffusion coefficient D and chain length N for both protein-like chains and SAW chains,i.e D～N^-α . Here the value of α for SAW chains is 1.02,however,the value of α for protein-like chains is 4.75,which is 4～5 times larger than that of SAW chains. Therefore,dynamics of protein-like chains is different from SAW chains completely. These investigations may provide some insights into dynamics of proteins.展开更多
文摘In this paper, molecular orientation behavior of polymethylene chains was investigated on the basis of considering long\|distance interactions by using the enumeration calculation method and the rotational isomeric state(RIS) model. The chain lengths are from \%N\%=12 to \%N=\%24, and the Lennord\|Jennes potential was adopted in the non\|local interaction calculations. The molecular orientation function(Legendre polynomial) may be well expressed as\$\$<P\-2(ζ)>/(λ\+2-λ\+\{-1\})=a(λ\+2-λ\+\{-1\})+b\$\$here\% a\% and\% b\% only depend on the chain length, and decrease with the increase of chain length, especially for \%b\%. In the meantime, we also calculate the Helmholtz free energy change in the process of tensile deformation. Comparisons with Gaussian chains are made, and our results are close to those obtained from the Roe and Krigbaum theory.
文摘Dynamics of protein-like chains are investigated by using Monte Carlo simulation method based on the modified orientation-dependent monomer-monomer interactions model (ODI). The diffusion coefficients for different chain length are calculated,and some comparisons with self-avoiding chains are also made. There exists a relationship between the diffusion coefficient D and chain length N for both protein-like chains and SAW chains,i.e D～N^-α . Here the value of α for SAW chains is 1.02,however,the value of α for protein-like chains is 4.75,which is 4～5 times larger than that of SAW chains. Therefore,dynamics of protein-like chains is different from SAW chains completely. These investigations may provide some insights into dynamics of proteins.
