Author
S. Roth
Bio: S. Roth is an academic researcher from Max Planck Society. The author has contributed to research in topics: Carbon nanotube & Polyacetylene. The author has an hindex of 44, co-authored 281 publications receiving 25195 citations.
Papers published on a yearly basis
Papers
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TL;DR: In this article, sound velocities v L, v T 1 and v T 2 have been measured at 15 MHz on Tm 3+0.87 Se and Tm 2.8+ 0.99 Se with uniaxial pressure.
46 citations
TL;DR: In this article, steady state photoconductivity in C60/C70 films was reported, and the action spectrum and the temperature dependence of the photocurrent were measured to separate a low and a high temperature regime showing different transport mechanisms similar to those found in amorphous silicon.
46 citations
TL;DR: In this article, the authors used a least squares analysis of 25 reflections of a single crystal of the trihalide anion I2Br 0.6I1.4Cl to determine the unit cell parameters of the new anion.
Abstract: [19] The single crystals of the Bu4NBr0.6I1.4Cl salt, were obtained by addition of IBr to a solution of Bu4NCl in ethanol at a reagent ratio of 1:0.5. Stoichiometry of the anion has been found by EDX. Based on a Raman study the anion consists of the I2Br ‐ (band at 140 cm ‐1 ), IBr2 ‐ (band at 150‐ 176 cm ‐1 ), BrICl ‐ (band at 225 cm ‐1 ), and ICl2 ‐ (band at 250‐263 cm ‐1 ) trihalide anions. [20] The X-ray diffraction data from single crystals for both trihalide salts were measured using an Enraf Nonius CAD4 diffractometer with graphite monochromatic Mo Ka radiation (k = 0.71073 a) at room temperature. Unit cell parameters of the new a¢¢¢- crystal were determined from a leastsquares analysis of 25 reflections. The intensities of 8106 non-zero reflections were collected by the x-scan method up to 2H = 50. The index range was ‐20 2 r(I), Rint = 0.011, were used in the structure analysis. Absorption correction was applied using the DIFABS algorithm. The main room temperature crystal data for the single crystal of 1 are as follows: a = 17.116(2), b = 8.956(1), c = 16.338(2) a, a = 88.09(2), b = 84.22(1), w = 81.22(2), V = 2462.1(5) a 3 , space group P1 ¯ , Z =3 ,M = 1024.89, dcalc =
45 citations
TL;DR: In this article, the photoluminescence of poly(p-phenylene vinylene) in the picosecond regime was investigated and it was shown that the non-radiative decay rate increases with increasing polymer chain conjugation length and that the luminescence decay is much faster for excitation parallel to the polymer chain than for perpendicular excitation.
Abstract: Time-resolved photoluminescence of poly(p-phenylene vinylene) in the picosecond regime shows that the non-radiative decay rate increases with increasing polymer chain conjugation length and that the luminescence decay is much faster for excitation parallel to the polymer chain than for perpendicular excitation. The results provide evidence for bimolecular recombination processes.
45 citations
TL;DR: In this paper, the influence of catalysts' activation conditions on their selectivity in carbon nanotubes CVD synthesis by means of methane decomposition reaction using Fe- and FeCo-catalysts synthesized via polymerized complex rout providing homogeneous distribution of catalytic components.
Abstract: In this paper we have investigated the influence of catalysts' activation conditions on their selectivity in carbon nanotubes CVD synthesis by means of methane decomposition reaction using Fe- and FeCo-catalysts synthesized via polymerized complex rout providing homogeneous distribution of catalytic components. It was shown that variation of catalysts' reduction conditions results in formation of different types of NTs (MWNTs or SWNTs). The most effective catalyst activation leading to formation of SWNTs consists in catalyst reduction by reaction mixture at high temperature. That can be explained in terms of carbon deposits nucleation on metals.
44 citations
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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
TL;DR: In this paper, the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations, are discussed.
Abstract: This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.
20,824 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
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
TL;DR: This review analyzes recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.
Abstract: Graphene is a wonder material with many superlatives to its name. It is the thinnest known material in the universe and the strongest ever measured. Its charge carriers exhibit giant intrinsic mobility, have zero effective mass, and can travel for micrometers without scattering at room temperature. Graphene can sustain current densities six orders of magnitude higher than that of copper, shows record thermal conductivity and stiffness, is impermeable to gases, and reconciles such conflicting qualities as brittleness and ductility. Electron transport in graphene is described by a Dirac-like equation, which allows the investigation of relativistic quantum phenomena in a benchtop experiment. This review analyzes recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.
12,117 citations