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

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Graphene is a wonder material with many superlatives to its name. It is the thinnest known material in the universe and the strongest ever measured. Its charge carriers exhibit giant intrinsic mobility, have zero effective mass, and can travel for micrometers without scattering at room temperature. Graphene can sustain current densities six orders of magnitude higher than that of copper, shows record thermal conductivity and stiffness, is impermeable to gases, and reconciles such conflicting qualities as brittleness and ductility. Electron transport in graphene is described by a Dirac-like equation, which allows the investigation of relativistic quantum phenomena in a benchtop experiment. This review analyzes recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.

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Graphene: Status and Prospects

The chemistry of graphene oxide is discussed in this critical review Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene-like materials, is also discussed This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references)

/pdf/the-chemistry-of-graphene-oxide-507zcedhhu.pdf

The chemistry of graphene oxide

An improved method for the preparation of graphene oxide (GO) is described. Currently, Hummers’ method (KMnO4, NaNO3, H2SO4) is the most common method used for preparing graphene oxide. We have found that excluding the NaNO3, increasing the amount of KMnO4, and performing the reaction in a 9:1 mixture of H2SO4/H3PO4 improves the efficiency of the oxidation process. This improved method provides a greater amount of hydrophilic oxidized graphene material as compared to Hummers’ method or Hummers’ method with additional KMnO4. Moreover, even though the GO produced by our method is more oxidized than that prepared by Hummers’ method, when both are reduced in the same chamber with hydrazine, chemically converted graphene (CCG) produced from this new method is equivalent in its electrical conductivity. In contrast to Hummers’ method, the new method does not generate toxic gas and the temperature is easily controlled. This improved synthesis of GO may be important for large-scale production of GO as well as the ...

https://www.researchgate.net/file.PostFileLoader.html?id=54ca19b4cf57d79a768b4618&assetKey=AS%3A273691751976961%401442264606356

Improved Synthesis of Graphene Oxide

Turbostratic layers in 2D materials have an interlayer misalignment. The lack of alignment expands the intrinsic interlayer distances and weakens the optical and electronic interactions between adjacent layers. This introduces properties distinct from those structures with well‐aligned lattices and strong coupling interactions. However, direct and rapid synthesis of turbostratic materials remains a challenge owing to their thermodynamically metastable properties. Here, a flash Joule heating (FJH) method to achieve bulk synthesis of boron–carbon–nitrogen ternary compounds with turbostratic structures by a kinetically controlled ultrafast cooling process that takes place within milliseconds (103 to 104 K s−1) is reported. Theoretical calculations support the existence of turbostratic structures and provide estimates of the energy barriers with respect to conversion into the corresponding well‐aligned counterparts. When using non‐carbon conductive additives, a direct synthesis of boron nitride is possible. The turbostratic nature facilitates mechanical exfoliation and more stable dispersions. Accordingly, the addition of flash products to a poly(vinyl alcohol) nanocomposite film coating a copper surface greatly improves the copper's resistance to corrosion in 0.5 m sulfuric acid or 3.5 wt% saline solution. FJH allows the use of bulk materials as reactants and provides a rapid approach to large quantities of the hitherto hard‐to‐access turbostratic materials.

Turbostratic Boron–Carbon–Nitrogen and Boron Nitride by Flash Joule Heating

Anodes, cathodes, and separators for batteries (electrochemical energy storage devices). The anodes are Li metal anodes having lithiated carbon films (Li-MWCNT) (as dendrite suppressors and protective coatings for the Li metal anodes). The cathodes are sulfurized carbon cathodes. The separators are GNR-coated (or modified) separators. The invention includes each of these separately (as well as in combination both with each other and with other anodes, cathodes, and separators) and the methods of making each of these separately (and in combination). The invention further includes a battery that uses at least one of (a) the anode having a lithiated carbon film, (b) the sulfurized carbon cathode, and (c) the GNR-modified separator in the anode/cathode/separator arrangement. For instance, a full battery can include the sulfurized carbon cathode in combination with the Li-MWCNT anode or a full battery can include the sulfurized carbon cathode in combination with other anodes (such as a GCNT-Li anode).

Anodes, cathodes, and separators for batteries and methods to make and use same

Protecting Groups for Organoselenium Compounds.

New potential molecular electronics devices have been synthesized based on our knowledge of systems that we previously studied. Research has shown that simple molecular systems demonstrate negative differential resistance (NDR) and memory characteristics. The new molecules rely primarily on the redox properties of the compounds to improve upon the solid-state characteristics already observed. Electrochemical tests have been performed in order to evaluate the redox properties with the hope that the electrochemical results can be used as a predictive tool to evaluate the usefulness of those compounds in device configurations.

Biphenyl- and Fluorenyl-Based Potential Molecular Electronic Devices.

Photoemission spectra of self-assembled monolayers of para-phenylene-ethynylene thiols chemisorbed on gold have
been measured. Three compounds were studied: 4,4'-bis(phenylethynyl)benzenethiol, 4-(phenylethynyl)benzenethiol,
and benzenethiol. The monolayer spectra were interpreted with the aid of gas-phase photoemission spectra of 4,4'-
bis(phenylethynyl)benzenethiol and benzenethiol. The work function of the monolayer-covered surface and alignment
of the highest occupied π-state of the monolayer relative to the Fermi level of the substrate were determined from the
monolayer spectra. The work function of the monolayer-covered surface decreased relative to that of the bare substrate
by about an electronvolt. The shift is attributed to changes in the charge distribution at the interface associated with
chemisorption. No statistically significant trend in the work function shift was observed with respect to oligomer
length. This observation points to a near-constant interface dipole and the role of the gold-sulfur bond in determining
energy-level alignment.

James M. Tour

Papers

Turbostratic Boron–Carbon–Nitrogen and Boron Nitride by Flash Joule Heating

Anodes, cathodes, and separators for batteries and methods to make and use same

Protecting Groups for Organoselenium Compounds.

Biphenyl- and Fluorenyl-Based Potential Molecular Electronic Devices.

Energy-level alignment of aryl thiols chemisorbed on metal surfaces: implications for charge transport