Hu-Jun Qian

Learn More
The self-assembly processes of miktoarm star-like block copolymers (Ax1)y-C-(Bx2)y, in which y homopolymer chains of type A with chain length x1 as well as y chains of type B with chain length x2 are connected to a center core C, are investigated by using Brownian dynamics simulations. We focus on the selective solvent condition, i.e., the solvent is poor(More)
P. T. Araujo,1 I. O. Maciel,1 P. B. C. Pesce,1 M. A. Pimenta,1 S. K. Doorn,2 H. Qian,3 A. Hartschuh,3 M. Steiner,4 L. Grigorian,5 K. Hata,6 and A. Jorio1,7 1Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 30123-970 Brazil 2Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA(More)
Multiscale modeling of a polymeric system is a challenging task in polymer physics. Here we introduce a bottom-up and then top-down scheme for the simulation of polyethylene (PE). The coarse-grained numerical potential for PE is derived through an automatic updating program by mapping its radial distribution function (RDF) from the Lowe-Andersen temperature(More)
IBIsCO is a parallel molecular dynamics simulation package developed specially for coarse-grained simulations with numerical potentials derived by the iterative Boltzmann inversion (IBI) method (Reith et al., J Comput Chem 2003, 24, 1624). In addition to common features of molecular dynamics programs, the techniques of dissipative particle dynamics (Groot(More)
The influence of polymerization on the phase separation of binary immiscible mixtures has been investigated by the dissipative particle dynamics simulations in two dimensions. During polymerization, the bulk viscosity increases, which consequently slows down the spinodal decomposition process. The domain size growth is monitored in the simulations. The(More)
We discuss the description of water and hydration effects that employs an approximate density functional theory, DFTB3, in either a full QM or QM/MM framework. The goal is to explore, with the current formulation of DFTB3, the performance of this method for treating water in different chemical environments, the magnitude and nature of changes required to(More)
Comprehensive three-dimensional dissipative particle dynamics simulations are carried out to elucidate the diffusion mechanism of a strongly adsorbed polymer chain on a solid surface in dilute solutions. We find Rouse and reptation dynamics for polymer chain diffusing on smooth and rough surfaces (with obstacles or sticking points), respectively. Combining(More)
GALAMOST [graphics processing unit (GPU)-accelerated large-scale molecular simulation toolkit] is a molecular simulation package designed to utilize the computational power of GPUs. Besides the common features of molecular dynamics (MD) packages, it is developed specially for the studies of self-assembly, phase transition, and other properties of polymeric(More)
In this contribution, we apply a microscopic technique that relies on the enhanced electric field near a sharp, laserirradiated metal tip that acts as a highly confined light source. The tip is used for the local excitation of the optical response of single-walled carbon nanotubes (SWNT) deposited on glass. We demonstrate photoluminescence and Raman imaging(More)
The reaction of C2 radical with NO molecule is studied at the B3LYP/6-311G(d) level of theory. Both doublet and quartet potential energy surfaces (PES) are considered. On the doublet potential energy surface, we obtain four major pathways in which the pathways C2 + NO h 1 CCNO f 2 (NC)CO f 3 CNCO f P1 CN + CO and C2 + NO h 1 f 4 CC(NO) f 2 f 3 f P1 CN + CO(More)