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

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

Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

/pdf/electronics-and-optoelectronics-of-two-dimensional-2jbqr1unvw.pdf

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

/pdf/a-comprehensive-review-of-zno-materials-and-devices-21a3zjadem.pdf

A comprehensive review of zno materials and devices

Synthesis of Ultra‐Long and Highly Oriented Silicon Oxide Nanowires from Liquid Alloys.

/pdf/perspectives-on-carbon-nanotubes-and-graphene-raman-29vacqsn6v.pdf

Perspectives on Carbon Nanotubes and Graphene Raman Spectroscopy

Mesostructured siliceous cellular foams (mesocellular foams, MCFs) with homogeneous ultra-large mesopores are described. MCFs consist of uniform spherical cells 21-36 nm in diameter and possess surface areas up to 900 m2/g. Uniform windows, 7-18 nm in diameter, interconnect the cells to form a continuous 3-D pore system, which makes the MCFs attractive candidates for supports for catalysis and in separation and immobilization involving large molecules. They may be of interest in low-dielectric applications. The size of the cells can be controlled by the concentration of the added organic cosolvent. Adding small amounts of NH4F selectively enlarges the windows. We propose that the MCFs are templated by oil-inwater microemulsion droplets. The large-pore MCF materials resemble aerogels, with the benefit of a facilitated synthesis procedure in combination with well-defined pores and wall structure.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1946427400165364

Siliceous Mesostructured Cellular Foams with Uniformly Sized and Shaped Pores

Recent research on carbon nitride thin films grown using pulsed laser deposition combined with atomic beam techniques is reviewed. the composition, growth mechanism and phases of these films have been systematically investigated. the nitrogen composition was found to increase to a limiting value of 50% as the fluence was decreased for laser ablation at both 532 nm and 248 nm wavelengths. Time of flight mass spectroscopy investigations of the ablation products have shown that the fluence variations affect primarily the yield of the carbon reactant. these experiments demonstrate that the overall film growth rate determines the average nitrogen composition, and furthermore, suggest that a key step in the growth mechanism involves a surface reaction between carbon and nitrogen. INfrared spectroscopy has been used to assess the phases present in the carbon nitride thin films as a function of the overall nitrogen content. these measurements have shown that a cyanogen-like impurity occurs in films with nitrogen compositions greater than 30%. Studies of thermal annealing have shown, however, that this impurity phase can be eliminated to yield a single phase C2N material. IN addition, systematic studies of the electrical resistivity and thermal conductivity of the carbon nitride films are discussed.

Growth and Properties of Carbon Nitride Thin Films

Nanofluidic devices incorporating inorganic nanotubes fluidly coupled to channels or nanopores for supplying a fluid containing chemical or bio-chemical species are described. In one aspect, two channels are fluidly interconnected with a nanotube. Electrodes on opposing sides of the nanotube establish electrical contact with the fluid therein. A bias current is passed between the electrodes through the fluid, and current changes are detected to ascertain the passage of select molecules, such as DNA, through the nanotube. In another aspect, a gate electrode is located proximal the nanotube between the two electrodes thus forming a nanofluidic transistor. The voltage applied to the gate controls the passage of ionic species through the nanotube selected as either or both ionic polarities. In either of these aspects the nanotube can be modified, or functionalized, to control the selectivity of detection or passage.

Peidong Yang

Papers

Synthesis of Ultra‐Long and Highly Oriented Silicon Oxide Nanowires from Liquid Alloys.

Perspectives on Carbon Nanotubes and Graphene Raman Spectroscopy

Siliceous Mesostructured Cellular Foams with Uniformly Sized and Shaped Pores

Growth and Properties of Carbon Nitride Thin Films

Inorganic nanotubes and electro-fluidic devices fabricated therefrom