Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

A surface science perspective on TiO2 photocatalysis

Research into extreme water-repellent surfaces began many decades ago, although it was only relatively recently that the term superhydrophobicity appeared in literature Here we review the work on the preparation of superhydrophobic surfaces, with focus on the different techniques used and how they have developed over the years, with particular focus on the last two years We discuss the origins of water-repellent surfaces, examining how size and shape of surface features are used to control surface characteristics, in particular how techniques have progressed to form multi-scaled roughness to mimic the lotus leaf effect There are notable differences in the terminology used to describe the varying properties of water-repellent surfaces, so we suggest some key definitions

Progess in superhydrophobic surface development.

Transparent conductors as solar energy materials: A panoramic review

Coating carbon nanotubes by spontaneous oxidative polymerization of dopamine

The feasibility of applying photocatalytic technology for removal of nitrogen oxide (NO) and volatile organic compounds (VOCs) at typical indoor air level using TiO2 (Degussa P-25) were investigated. Benzene, toluene, ethylbenzene and o-xylene (BTEX) were chosen because they are the most abundant in the indoor environments. The concentrations conducted for this study is 200 parts per billion (ppb) NO and less than 100 ppb for BTEX respectively. Sensitive analyses were conducted for NO, BTEX and a mixture of NO and BTEX under different residence time, levels of humidity and initial concentrations. Under the experimental conditions, it was found that the presence of NO promoted the photodegradation of BTEX under low and high humidity levels. However, at moderate humidity levels, the presence of NO reduced the photodegradation of BTEX. The promotion effect decreased with decreasing residence time. The overall photodegradation of NO and BTEX decreased acutely in relation to increasing humidity. In addition, NO2 was found to react with BTEX as well.

Photodegradation of volatile organic compounds (VOCs) and NO for indoor air purification using TiO2: promotion versus inhibition effect of NO

A major challenge that prohibits the practical application of single/double-transition metal (3d-M) oxides as oxygen evolution reaction (OER) catalysts is the high overpotentials during the electro...

Valence Engineering via Selective Atomic Substitution on Tetrahedral Sites in Spinel Oxide for Highly Enhanced Oxygen Evolution Catalysis.

Optical properties of epitaxial and polycrystalline Sr[sub 1.8]Ca[sub 0.2]NaNb[sub 5]O[sub 15] thin-film waveguides grown by pulsed laser deposition

Upconversion photoluminescence (PL) of Er3+-doped BaTiO3 (BTO) with perovskite ABO3 structure is studied in terms of Er3+ substitutions for Ba (A-) and Ti (B-site) with different Er3+ doping concentrations. PL quenching with an increase Er3+ doping concentration is investigated based on the structural change and energy transfer of cross-relaxation process in BTO: Er, i.e. 2H11/2 + 4I15/2→4I9/2 + 4I13/2. Temperature dependence of the PL in BTO: Er is revealed, which is associated with phase transitions of BTO host. The results imply that the emission from substituted Er3+ ions may be used as a structural probe for the ferroelectric titanates.

Chee Leung Mak

Papers

Coating carbon nanotubes by spontaneous oxidative polymerization of dopamine

Photodegradation of volatile organic compounds (VOCs) and NO for indoor air purification using TiO2: promotion versus inhibition effect of NO

Valence Engineering via Selective Atomic Substitution on Tetrahedral Sites in Spinel Oxide for Highly Enhanced Oxygen Evolution Catalysis.

Optical properties of epitaxial and polycrystalline Sr[sub 1.8]Ca[sub 0.2]NaNb[sub 5]O[sub 15] thin-film waveguides grown by pulsed laser deposition

Effects of site substitutions and concentration on upconversion luminescence of Er 3+ -doped perovskite titanate