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

Intuitive interpretation of the effect of inhomogeneous layers in optical coatings is often difficult. In this work, we use admittance diagrams to interpret some properties of accidental and premeditated optical inhomogeneities. The effect of accidental homogeneous and inhomogeneous transition layers on the spectral properties of a single film is presented. We also give an original explanation for the suppression of harmonics and sidelobes in the spectra of rugate filters.

Admittance diagrams of accidental and premeditated inhomogeneous optical coatings

A deposition-and-etch process allows one to obtain continuous thin films below the regular percolation threshold, enabling the deposition of ultra-thin silver films in atypical conditions, yielding improved microstructures and/or optical properties. 

Continuous ultra-thin silver films obtained by a two-step method for improved control of the optical and microstructural characteristics

The photo-isomerization of azo-chromophores in a nonlinear optical side-chain polymer permits the orientation of the dipoles under an applied electric field even well below the glass-transition temperature of the polymer. As the dipoles become orientable only within the penetration depth of the pump light, the technique is especially suitable for the preparation of poling patterns across the thickness of the polymer. Pyroelectrical investigations allow for an in-situ examination of the photo-induced poling process and for an analysis of the resulting nonuniform dipole-orientation patterns. For long-time exposures to the short-wavelength pump light, a photo-induced degradation of the chromophore molecules (photo-bleaching) is observed, which is analyzed by pyroelectrical (thermal) analysis, optical techniques and X-ray photoelectron spectroscopy.

http://ieeexplore.ieee.org/iel2/3863/11280/00517760.pdf

In-situ pyroelectrical study of the polarization dynamics in nonlinear optical polymers and physico-chemical investigation of photo-induced degradation

We propose to include dispersion in the Fourier transform method by applying a multiplicative correction factor and a wavelength scaling of the Q function. Results show good agreement with the target.

A simple way to include dispersion in the design of graded-index optical filters by the Fourier transform method

SiNx:H alloys (0.47<x<1.35) are prepared by varying the duty cycle in a pulsed RF PECVD process, while keeping the gas mixture constant; a high-quality Fabry-Perot filter is fabricated.

Ludvik Martinu

Papers

Admittance diagrams of accidental and premeditated inhomogeneous optical coatings

Continuous ultra-thin silver films obtained by a two-step method for improved control of the optical and microstructural characteristics

In-situ pyroelectrical study of the polarization dynamics in nonlinear optical polymers and physico-chemical investigation of photo-induced degradation

A simple way to include dispersion in the design of graded-index optical filters by the Fourier transform method

Properties, Growth and Filter Applications of a-SiN x :H Alloys Prepared in Pulsed Radiofrequency Plasma