Results

1 - 25 of 34
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Monte Carlo (MC) simulations are used to study the dynamics of polymer translocation through a nanopore in the limit where the translocation rate is sufficiently slow that the polymer maintains a state of conformational quasi-equilibrium. The system is modeled as a flexible hard-sphere chain that tr...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Monte Carlo simulations are used to study the behavior of two polymers under confinement in a cylindrical tube. Each polymer is modeled as a chain of hard spheres. We measure the free energy of the system, F, as a function of the distance between the centers of mass of the polymers, lambda, and exam...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
We analyze the finite-size corrections to the free energy of crystals with a fixed center of mass. When we explicitly correct for the leading (ln N/N) corrections, the remaining free energy is found to depend linearly on 1/N. Extrapolating to the thermodynamic limit (N -->infinity), we estimate t...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Molecular dynamics simulations are used to study the equilibrium properties and collapse dynamics of a heteropolymer in the presence of an explicit solvent in two dimensions. The system consists of a single copolymer chain composed of hydrophobic (H) and hydrophilic (P) monomers, immersed in a Lenna...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Deuterium nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation times are used to investigate the guest and host molecular dynamics of solid 1,4-di-tert-butylbenzene-d4 (DTBB-d4), 1,4-di-tert-butylbenzene-d18 (DTBB-d18), the thiourea/ 1,4-di-tert-butylbenzene-d4 inclusion compound (TU...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Monte Carlo computer simulations were used to investigate the effects of shape anisotropy and electrostatic interactions as mechanisms for orientational ordering of solutes in nematic liquid crystals. The simulation results were analyzed in terms of two theories of solute ordering which derive mean-...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Molecular dynamics simulations were used to study the conformational dynamics of a bead-spring model polymer in an explicit solvent under good solvent conditions. The dynamics of the polymer chain were investigated using an analysis of the time autocorrelation functions of the Rouse coordinates of t...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
In this study we use multiple-quantum H-1-NMR spectroscopy to study butane, the simplest flexible alkane, dissolved in a nematic solvent. An analysis of the highly accurate H-1 dipolar coupling constants gives important information about conformational and orientational behavior, including the hans-...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
We examine the performance of various commonly used integration schemes in dissipative particle dynamics simulations. We consider this issue using three different model systems, which characterize a variety of different conditions often studied in simulations. Specifically, we clarify the performanc...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Solid-state H-2 NMR powder spectra and T-1 longitudinal relaxation data have been collected for carceplexes containing benzene and acetonitrile guest molecules. Analysis of the data suggests that benzene rotates rapidly about its C-6 axis with an activation energy of 25.8 +/- 0.4 kJ mol(-1). In addi...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Molecular dynamics simulations are used to study the coil-globule transition for a system composed of a bead-spring polymer immersed in an explicitly modeled solvent. Two different versions of the model are used, which are differentiated by the nature of monomer-solvent, solvent-solvent, and nonbond...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
We employ off-lattice Monte Carlo simulations to study lateral diffusion in lipid-sterol bilayers using a two-dimensional model system which has been designed to simulate the experimental phase diagrams of both lipid-cholesterol and lipid-lanosterol systems. We focus on the effects of varying sterol...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
We study the first order solid-fluid phase transition of a system of semi-flexible Lennard-Jones chains using molecular dynamics simulations. Thermodynamic integration methods are used to calculate the free energy of the solid and fluid phases. The solid phase free energy per chain can be calculated...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Multiple-quantum H-1 NMR spectroscopy was used to simplify the analysis of the complicated one-quantum spectrum of the 10-spin molecule biphenyl dissolved in a nematic solvent. An eight-quantum spectrum was analyzed to obtain estimates of all dipolar coupling constants and chemical shifts, which wer...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
We use molecular dynamics simulations to study an entropy-driven collapse transition of a flexible polymer in a solvent. Monomers and solvent particles interact with a steeply repulsive soft-sphere potential. We consider a nonadditive potential system in which the effective diameter describing the s...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
The anisotropic intermolecular forces responsible for the orientational ordering in liquid crystals are probed by comparing Monte Carlo (MC) simulations with experimental nuclear magnetic resonance (NMR) results for solutes in nematic liquid crystals. In a special liquid crystal mixture where all lo...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Deuterium nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation times were determined in order to study the dynamics of t-butyl groups in butylated hydroxytoluene. The results are consistent with a model first proposed by Beckmann et al. [J. Magn. Reson. 36, 199 (1979)], where there i...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Deuterium NMR spectra for solid [H-2(9)]tris(trimethylsilyl)amine were recorded at 77 K and in the region 114-353 K. At 77 K there is only fast rotation of the methyl groups. Between 122 and 171 K rotation of the trimethylsilyl groups and of the entire molecule (about its C3 axis) affect the deuteri...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Coarse-grained models that preserve hydrodynamics provide a natural approach to study collective properties of soft-matter systems. Here, we demonstrate that commonly used integration schemes in dissipative particle dynamics give rise to pronounced artifacts in physical quantities such as the compre...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
We study the equilibrium behavior and dynamics of a polymer collapse transition for a system composed of a short Lennard-Jones (LJ) chain immersed in a LJ solvent for solvent densities in the range of rho=0.6-0.9 (in LJ reduced units). The monomer hydrophobicity is quantified by a parameter lambdais...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
We report Monte Carlo simulations of the nematic-smectic phase transition for a system of hard spherocylinders with infinite length-to-diameter ratio. A finite-size scaling analysis suggests that this system undergoes a first-order phase transition. When combined with other simulations of the phase ...
[Page generation failure. The bibliography processor requires a browser with Javascript enabled.]
Monte Carlo computer simulations were used to investigate the phase behaviour of a Lebwohl-Lasher binary liquid-crystal mixture. A finite-size scaling analysis confirmed the first-order nature of the transition. The calculated nematic-isotopic phase coexistence region and the orientational order par...