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

To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Films and powders of TiO 2- x N x have revealed an improvement over titanium dioxide (TiO 2 ) under visible light (wavelength 2 has proven to be indispensable for band-gap narrowing and photocatalytic activity, as assessed by first-principles calculations and x-ray photoemission spectroscopy.

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Visible-Light Photocatalysis in Nitrogen-Doped Titanium Oxides

Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

This critical review shows the basis of photocatalytic water splitting and experimental points, and surveys heterogeneous photocatalyst materials for water splitting into H2 and O2, and H2 or O2 evolution from an aqueous solution containing a sacrificial reagent Many oxides consisting of metal cations with d0 and d10 configurations, metal (oxy)sulfide and metal (oxy)nitride photocatalysts have been reported, especially during the latest decade The fruitful photocatalyst library gives important information on factors affecting photocatalytic performances and design of new materials Photocatalytic water splitting and H2 evolution using abundant compounds as electron donors are expected to contribute to construction of a clean and simple system for solar hydrogen production, and a solution of global energy and environmental issues in the future (361 references)

Heterogeneous photocatalyst materials for water splitting

2.3. Evaluation of Photocatalytic Water Splitting 6507 2.3.1. Photocatalytic Activity 6507 2.3.2. Photocatalytic Stability 6507 3. UV-Active Photocatalysts for Water Splitting 6507 3.1. d0 Metal Oxide Photocatalyts 6507 3.1.1. Ti-, Zr-Based Oxides 6507 3.1.2. Nb-, Ta-Based Oxides 6514 3.1.3. W-, Mo-Based Oxides 6517 3.1.4. Other d0 Metal Oxides 6518 3.2. d10 Metal Oxide Photocatalyts 6518 3.3. f0 Metal Oxide Photocatalysts 6518 3.4. Nonoxide Photocatalysts 6518 4. Approaches to Modifying the Electronic Band Structure for Visible-Light Harvesting 6519

Semiconductor-based Photocatalytic Hydrogen Generation

A thermoelectric element includes a thermoelectric member made of thermoelectric materials and having a through hole, a pipe inserted into the through hole for making fluid flow, and a soaking member provided to the side of the thermoelectric element. The pipe and the soaking member respectively also function as an electrode of the thermoelectric member. A surface of the soaking member includes a blackened surface and a mirror surface. A thermoelectric generation system includes a container having a lighting window, the thermoelectric element housed in the container, a fluid feeder for feeding fluid into the pipe, and a power consumption source that consumes electric power generated by the thermoelectric element. The thermoelectric element is housed in the container so that the blackened surface is located under the lighting window.

Thermoelectric element and thermoelectric generation system

Mg2Si particles with diameters less than 1 μm are prepared by a solid state metathesis reaction of NaSi, MgCl2, and Na (BN crucible, 650 °C, 10 h).

A Metathesis Reaction Route to Obtain Fine Mg2Si Particles.

Photokatalytisches material, photokatalytischer artikel und verfahren zu ihrer herstellung

Al-doped ZnO ceramics were fabricated by the electrical field-assist sintering method and their thermoelectric properties were examined. When the current density of 10A/cm2 was applied, the electrical conductivity was increased by about 30 % compared with that of a specimen set in the same furnace without any applied current. The Seebeck coefficient was also increased by approximately 10%. The power factor was thus improved about 60%, reaching 1.3x10-3 W/mK2 at 1053K, which is one of the best power factor in bulk oxides. Analyses of Hall measurement and thermal conductivity showed that longer mean free paths of both electrons and phonons were obtained by the electrical field-assist sintering method, suggesting promotion of the grain growth and/or reduction of barriers at the grain boundary in the direction of current.

Thermoelectric Properties of Al-Doped ZnO Prepared by Electrical Field-Assist Sintering

L'invention concerne une matiere photocatalytique contenant des cristaux d'oxyde de titane et des anions X incorpores dans ceux-ci. Cette matiere peut etre preparee a l'aide d'un procede comportant une substitution d'anions X a certains sites d'oxygene des cristaux d'oxyde de titane, et/ou d'un procede comportant le dopage d'anions X entre des reseaux d'un cristal de titane, et/ou un procede comportant le dopage des joints des grains d'oxyde de titane, ou d'une combinaison de ces procedes. La matiere photocatalytique acquiert ainsi un nouveau niveau d'energie formee dans une largeur de bande interdite de l'oxyde de titane, qui lui confere une activite catalytique par absorption de lumiere visible. La matiere photocatalytique presente par consequent une activite photocatalytique satisfaisante au soleil, ainsi que dans une piece eclairee par une lampe fluorescente.

Ryoji Asahi

Papers

Thermoelectric element and thermoelectric generation system

A Metathesis Reaction Route to Obtain Fine Mg2Si Particles.

Photokatalytisches material, photokatalytischer artikel und verfahren zu ihrer herstellung

Thermoelectric Properties of Al-Doped ZnO Prepared by Electrical Field-Assist Sintering

Matiere catalytique et article photocatalytique