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Rodney S. Ruoff

Bio: Rodney S. Ruoff is an academic researcher from Ulsan National Institute of Science and Technology. The author has contributed to research in topics: Graphene & Graphene oxide paper. The author has an hindex of 164, co-authored 666 publications receiving 194902 citations. Previous affiliations of Rodney S. Ruoff include Texas State University & North Carolina State University.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate theoretically and experimentally that atomically thin boron nitride (BN) nanosheets as an adsorbent experience conformational changes upon surface adorption of molecules, increasing adsorption energy and efficiency.
Abstract: Surface interaction is extremely important to both fundamental research and practical application. Physisorption can induce shape and structural distortion (i.e. conformational changes) in macromolecular and biomolecular adsorbates, but such phenomenon has rarely been observed on adsorbents. Here, we demonstrate theoretically and experimentally that atomically thin boron nitride (BN) nanosheets as an adsorbent experience conformational changes upon surface adsorption of molecules, increasing adsorption energy and efficiency. The study not only provides new perspectives on the strong adsorption capability of BN nanosheets and many other two-dimensional nanomaterials but also opens up possibilities for many novel applications. For example, we demonstrate that BN nanosheets with the same surface area as bulk hBN particles are more effective in purification and sensing.

32 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of single crystal graphene on carbonization and graphitization of thin film polymers was investigated, showing that at the early stages of carbonization, carbon atoms in its near vicinity formed oriented layers parallel to the graphene layer.
Abstract: We report the effect of single crystal graphene on carbonization and graphitization of thin film polymers. Electron microscopy reveals that at the early stages of carbonization, graphene induces the carbon atoms in its near vicinity to form oriented layers parallel to the graphene layer. At elevated temperatures, these layers develop further to form extended graphitic (002) planes parallel to the graphene surface. For the samples which were heat treated and graphitized, grazing incidence X-ray scattering reveals that graphene narrows the distribution of graphite grain orientations. Based on these results, we propose that graphene can act as a structure directing agent in both the carbonization and graphitization of polymer thin films, and may provide an approach to realize single crystal graphite films, perhaps in combination with established techniques such as stress recrystallization.

32 citations

Journal ArticleDOI
27 Aug 2018-ACS Nano
TL;DR: A phase-field model is reported on, where the effects of oxygen on the number of nuclei, the energetics at the growth front, and the graphene island morphology on Cu are included, to guide the efficient growth of large single-crystal graphene of high quality.
Abstract: Mass production of large, high-quality single-crystalline graphene is dependent on a complex coupling of factors including substrate material, temperature, pressure, gas flow, and the concentration of carbon and hydrogen species Recent studies have shown that the oxidation of the substrate surface such as Cu before the introduction of the C precursor, methane, results in a significant increase in the growth rate of graphene while the number of nuclei on the surface of the Cu substrate decreases We report on a phase-field model, where we include the effects of oxygen on the number of nuclei, the energetics at the growth front, and the graphene island morphology on Cu Our calculations reproduce the experimental observations, thus validating the proposed model Finally, and more importantly, we present growth rate from our model as a function of O concentration and precursor flux to guide the efficient growth of large single-crystal graphene of high quality

32 citations

Journal ArticleDOI
TL;DR: It was shown that for the majority of these ILs, the reorientational dynamics are not in the extreme narrowing regime, but instead are in the dispersive relaxation regime, thus allowing a unique solution for the correlation time to be determined.
Abstract: The 14N NMR spin−lattice (R1) and spin−spin (R2) relaxation rates were determined as a function of temperature for a series of tetra-alkyl acyclic ammonium and cyclic pyrrolidinium ionic liquids (ILs). Through the use of the R2/R1 ratio method, it was shown that for the majority of these ILs, the reorientational dynamics are not in the extreme narrowing regime, but instead are in the dispersive relaxation regime, thus allowing a unique solution for the correlation time to be determined. The temperature variation of the R2 relaxation rate, along with the temperature variation of the calculated correlation times, allowed activation energies for the reorientational dynamics to be measured and compared. In addition, these NMR relaxation experiments enabled the 14N quadrupolar coupling product to be extracted, which revealed surprising temperature dependence. Collectively, the 14N NMR results allow the impact of cation and anion identity on the local reorientational dynamics of these ILs to be delineated.

32 citations

Patent
08 Dec 1997
TL;DR: In this article, the size and shape of the elements predetermine the size of the particles, and the shape of elements can also influence the shape and size of their constituent parts.
Abstract: Micron-sized particles are produced in quantity by one of various methods, including generally the steps of preparing a substrate surface through a lithographic process, the surface being characterized by defining a plurality of elements, depositing a layer of particle material on the substrate surface including the elements, processing the substrate surface to isolate the material deposited on the elements, and separating the particles from the elements. The size and shape of the elements predetermine the size and shape of the particles. The elements may comprise, inter alia, pillars of photoresist or spaces on the substrate surrounded and defined by photoresist.

31 citations


Cited by
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Journal ArticleDOI
TL;DR: 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 can now be mimicked and tested in table-top experiments.
Abstract: 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.

35,293 citations

01 May 1993
TL;DR: 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.
Abstract: 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.

29,323 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组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�ly.
Abstract: 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。

18,940 citations

Journal ArticleDOI
Changgu Lee1, Xiaoding Wei1, Jeffrey W. Kysar1, James Hone1, James Hone2 
18 Jul 2008-Science
TL;DR: Graphene is established as the strongest material ever measured, and atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.
Abstract: 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.

18,008 citations