Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

The rise of graphene

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

We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force-displacement behavior is interpreted within a framework of nonlinear elastic stress-strain response, and yields second- and third-order elastic stiffnesses of 340 newtons per meter (N m(-1)) and -690 Nm(-1), respectively. The breaking strength is 42 N m(-1) and represents the intrinsic strength of a defect-free sheet. These quantities correspond to a Young's modulus of E = 1.0 terapascals, third-order elastic stiffness of D = -2.0 terapascals, and intrinsic strength of sigma(int) = 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.

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Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene

One of the greatest challenges facing nanotechnology is the ability to selectively place nanoscale entities in specific locations and subsequently interconnect these devices. Several methods have been proposed and the relative strengths of each technique will become apparent in time. One method that has received considerable attention in recent years is nanoimprint or nanostamp lithography. These techniques have shown resolution down to 10 nm, can be applied over large areas, are relatively inexpensive, and have several variations to accommodate different processing tasks. One common challenge in nanoimprint or nanostamp lithography is the fabrication of the imprinter or stamp. The features on the imprinter are usually fabricated using e-beam lithography and then etched. The etching step is often the determining factor in the quality of the imprinter. We have evaluated etching of 50 nm and 250 nm features in silicon and silicon dioxide using 16 different etching recipes. The features have been etched down approximately 200 nm resulting in an aspect ratio of 4 to 1 for the 50 nm features. The primary evaluation criteria is the anisotropy of the etch with the goal of achieving vertical sidewalls. In this paper, we present the 16 different etching recipes, the chamber conditions for three different reactors, and qualitative evaluations based upon SEM micrographs of each etch. For this work, we will concentrate on the nanoscale etching of SiO/sub 2/. Several etching recipes are shown to be able to produce near-vertical walls for 50 nm features etched down 200 nm.

http://users.rowan.edu/~krchnavek/Rowan_University/Research-Pubs_files/IEEE_NANO_2001.pdf

An empirical study of etching for the fabrication of nanoscale imprinters

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Structural and mechanical properties of `graphene oxide'-based paper

The intrinsic properties of graphene such as high in plane elastic modulus and low out of plane bending stiffness make the graphene to create a variety of new structures through fold, twist, and/or fracture [1]. According to the preceding research results, if the graphene becomes folded with specific stacking angle, it is expected to show novel characteristics such as interferometric effects when the magnetic fields are engaged into the graphene fold region [2]. It is also known that the charge confinement effect can be seen through the conductance test across the graphene fold [3]. Thus, graphene fold may be used as a promising material for valleytronic applications, particularly in protocols for quantum computation [4]. In general, when the graphene is synthesized through CVD method on the metal substrates, lots of ribbon-like graphene folds can be made during the cooling process after graphene growth at high temperature due to the difference in thermal contraction characteristics between grown graphene layers and used metal substrate. Typically, these graphene folds are randomly formed

Structural Analysis for Highly Aligned Graphene Fold on Cu(111) Substrate

Multiwalled BN nanotubes are grown from nickel boride catalyst particles by chemical vapor deposition at 1000−1100 °C using borazine, B3N3H6, as the precursor. This precursor is generated in situ from molten salt that forms from mixtures of (NH4)2SO4, NaBH4, and Co3O4 at 300−400 °C. The BN nanotubes have concentric-tube structures, are free of internal closures, have crystalline walls, and exhibit lengths of up to ∼5 μm. The nanotubes often possess bulbous, flag-like, or club-like tip closures. A root-growth mechanism is proposed for the catalyzed process.

CVD Growth of Boron Nitride Nanotubes.

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Rodney S. Ruoff

Papers

An empirical study of etching for the fabrication of nanoscale imprinters

Structural and mechanical properties of `graphene oxide'-based paper

Structural Analysis for Highly Aligned Graphene Fold on Cu(111) Substrate

CVD Growth of Boron Nitride Nanotubes.

Reduction Kinetics of Graphene Oxide Determined by Temperature Programmed Desorption