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

Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

Aggregation-Induced Emission: Together We Shine, United We Soar!

https://cyberleninka.org/article/n/933162.pdf

Hydrogels in drug delivery: progress and challenges

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.

/pdf/averages-of-b-hadron-c-hadron-and-tau-lepton-properties-as-29qrkk2j2g.pdf

Averages of b-hadron, c-hadron, and tau-lepton properties as of early 2012

Regulation of orientation birefringence for cellulose acetate film: The role of crystallization and orientation.

Orientation Birefringence Regulation for the Binary Blend Film of Cellulose Triacetate and Rigid-Rod-Like 5CB Molecules

Tritium analysis in zirconium film with BIXS and EBS: Generality test of Al thin film as the β-ray stopping layer in BIXS

The structural evolution of virgin and crosslinked polytetrafluoroethylene (PTFE) during stretching was studied by in situ synchrotron small-angle X-ray scattering (SAXS) Both yield and tensile stress of crosslinked PTFE increased with increasing crosslinking density During stretching, for virgin PTFE, amorphous chains gradually turned to tensile direction at early stage, perpendicularly arranged lamellar stacks appeared at high strains (>140%) While for crosslinked PTFE, lamellar structure was observed even at lower strains; with increasing irradiation dose, the lamellar structure became obvious and the long period decreased Four-point SAXS patterns were observed only in 3000kGy-dosed PTFE during deformation, which indicated that an alternately tilted lamella arrangement called herringbone structure was formed Radiation dose induces crosslinked networks formed, which can carry part of local stress during deformation, resulting in the increase of yield and tensile stress Crosslinking density is an important factor on structural evolution In addition, a deformation mechanism of different crosslinked PTFE is proposed (c) 2013 Wiley Periodicals, Inc J Appl Polym Sci 2014, 131, 39883

In situ small angle X-ray scattering study on structural evolution of crosslinked polytetrafluoroethylene during deformation

The invention provides a polyolefin nanofiber membrane with an interlaced nanofiber network structure. The porosity of the polyolefin nanofiber membrane is 50%-58%. In the invention, the polyolefin nanofiber membrane with the interlaced nanofiber network structure is obtained by taking the polyolefin as raw materials, with the nanofiber network structure evenly distributed, so that evenly distributed pores can be formed. Moreover, the preparation method provided by the invention has the advantages of simple structure and mild conditions, in favor of industrialization.

Liangbin Li

Papers

Regulation of orientation birefringence for cellulose acetate film: The role of crystallization and orientation.

Orientation Birefringence Regulation for the Binary Blend Film of Cellulose Triacetate and Rigid-Rod-Like 5CB Molecules

Tritium analysis in zirconium film with BIXS and EBS: Generality test of Al thin film as the β-ray stopping layer in BIXS

In situ small angle X-ray scattering study on structural evolution of crosslinked polytetrafluoroethylene during deformation

Polyolefin nanofiber membrane and preparation method thereof