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

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Small but strong: A review of the mechanical properties of carbon nanotube–polymer composites

Analysis of the nonisothermal melt and cold crystallization kinetics of poly(aryl ether ether ketone ketone) (PEEKK) was performed by using differential scanning calorimetry (DSC). The Avrami equation modified by Jeziorny could describe only the primary stage of nonisothermal crystallization of PEEKK. And, the Ozawa analysis, when applied to this polymer system, failed to describe its nonisothermal crystallization behavior. A new and convenient approach for the nonisothermal crystallization was proposed by combining the Avrami equation with the Ozawa equation. By evaluating the kinetic parameters in this approach, the crystallization behavior of PEEKK was analyzed. According to the Kissinger method, the activation energies were determined to be 189 and 328 kJ/mol for nonisothermal melt and cold crystallization, respectively.

Nonisothermal melt and cold crystallization kinetics of poly(aryl ether ether ketone ketone)

Multiwalled carbon nanotubes (MWNTs)/nylon-6 (PA6) nanocomposites with different MWNTs loadings have been prepared by the simple melt-compounding approach. A fine and homogeneous dispersion of MWNT...

Morphology and Mechanical Properties of Multiwalled Carbon Nanotubes Reinforced Nylon-6 Composites

Poly(e-caprolactone) (PCL)/layered double hydroxide (LDH) nanocomposites were prepared success- fully via simple solution intercalation. The nonisothermal melt crystallization kinetics of neat PCL and its LDH nano- composites was investigated with the Ozawa, Avrami, and combined Avrami-Ozawa methods. The Ozawa method failed to describe the crystallization kinetics of the studied systems. The Avrami method was found to be useful for describing the nonisothermal crystallization behavior, but the parameters in this method do not have explicit meaning for nonisothermal crystallization. The combined Avrami- Ozawa method explained the nonisothermal crystallization behavior of PCL and its LDH nanocomposites effectively. The kinetic results and polarized optical microscopy obser- vations indicated that the addition of LDH could affect the mechanism of nucleation and growth of the PCL matrix. The Takhor model was used to analyze the activation ener- gies of nonisothermal crystallization. V C 2010 Wiley Periodicals,

Crystallization behavior of poly(ε-caprolactone)/layered double hydroxide nanocomposites

The challengesfor developing high-performance CNTs/polymer nano-composites are (i) homogeneous dispersion of CNTs inthe polymeric matrix and (ii) strong interfacial interac-tions so as to effect efficient load transfer from thepolymeric matrix to the CNTs. Without chemicallybonding, load transfer between the CNTs and thematrix mainly comes from electrostatic and van derWaals interactions.

Tianxi Liu

Papers

Nonisothermal melt and cold crystallization kinetics of poly(aryl ether ether ketone ketone)

Morphology and Mechanical Properties of Multiwalled Carbon Nanotubes Reinforced Nylon-6 Composites

Crystallization behavior of poly(ε-caprolactone)/layered double hydroxide nanocomposites

Carbon Nanotubes Reinforced Nylon-6 Composite Prepared by Simple Melt-Compounding

Biopolymer chitosan/montmorillonite nanocomposites: Preparation and characterization