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

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

Noble metal nanoparticles are capable of confining resonant photons in such a manner as to induce coherent surface plasmon oscillation of their conduction band electrons, a phenomenon leading to two important properties. Firstly, the confinement of the photon to the nanoparticle's dimensions leads to a large increase in its electromagnetic field and consequently great enhancement of all the nanoparticle's radiative properties, such as absorption and scattering. Moreover, by confining the photon's wavelength to the nanoparticle's small dimensions, there exists enhanced imaging resolving powers, which extend well below the diffraction limit, a property of considerable importance in potential device applications. Secondly, the strongly absorbed light by the nanoparticles is followed by a rapid dephasing of the coherent electron motion in tandem with an equally rapid energy transfer to the lattice, a process integral to the technologically relevant photothermal properties of plasmonic nanoparticles. Of all the possible nanoparticle shapes, gold nanorods are especially intriguing as they offer strong plasmonic fields while exhibiting excellent tunability and biocompatibility. We begin this review of gold nanorods by summarizing their radiative and nonradiative properties. Their various synthetic methods are then outlined with an emphasis on the seed-mediated chemical growth. In particular, we describe nanorod spontaneous self-assembly, chemically driven assembly, and polymer-based alignment. The final section details current studies aimed at applications in the biological and biomedical fields.

Gold Nanorods: From Synthesis and Properties to Biological and Biomedical Applications

Transparent conductors as solar energy materials: A panoramic review

Plasma-enhanced chemical vapor deposition is very attractive for the fabrication of optical filters on plastic substrates. We found, using ex situ and in situ spectroellipsometric analysis, that plasma deposition of silicon nitride as a high-refractive-index material, on bare and plasma-pretreated polycarbonate (PC) substrates, gives rise to the formation of a 50- to 100-nm-thick interfacial region (or interphase). We show that plasma pretreatment can reduce the thickness of this interphase by 50% from that obtained with deposition on untreated PC, possibly due to interface stabilization. An optical model based on real-time in situ measurements is proposed to describe the interphase refractive index profile. This model is fully supported by complementary crosssectional transmission-electron-microscopy observations. Important consequences for the mechanical performance (adhesion and scratch resistance) and optical design of optical coatings on plastics are discussed.

Interphase in plasma-deposited silicon nitride optical films on polycarbonate: in situ ellipsometric characterization

Conformal multilayer TiO2/SiO2/TiO2 coatings were deposited on the surface of ∼27 μm spherical soda lime glass (SLG) particles using fluidized bed chemical vapor deposition at atmospheric pressure. Cost-effective precursors of titanium and silicon chlorides together with water were employed to deposit titania and silica films at 300 °C and room temperature, respectively. Focused ion beam cross-sectional transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area analysis, and X-ray diffraction were used to characterize the multilayer-coated particles. The results revealed a pinhole-free and uniform multilayer of anatase TiO2 and amorphous SiO2 with a thickness of ∼110 and 20 nm. Moreover, the photodegradation performance of the coated particles was examined by the degradation of methylene blue as the model reaction. It was found that a multilayer thin film of titania and silica can effectively prevent...

Ludvik Martinu

Papers

Interphase in plasma-deposited silicon nitride optical films on polycarbonate: in situ ellipsometric characterization

Conformal Multilayer Photocatalytic Thin Films on Fine Particles by Atmospheric Pressure Fluidized Bed Chemical Vapor Deposition

Polymer Surface Modification by Dual-Frequency Plasma Treatment

Plasma Deposition and Testing of Hard Coatings on Plastics

Characterization of carburized tantalum layers prepared in inductive RF plasma