Carbon nanotubes geometries

Abstract—The fundamental relations governing the geometry of carbon nanotubes are reviewed, and explicit examples are pre.sented. A framework is given for the symmetry properties of carbon nanotubes for both symmorphic and non-symmorphic tubules which have screw-axis symmetry. The implications of symmetry on the vibrational and electronic structure of ID carbon nanotube systems are considered. The corresponding properties of double-wall nanotubes and arrays of nanotubes are also discussed. 

Of particular importance to carbon nanotube physics are the many possible symmetries or geometries that can be realized on a cylindrical surface in carbon nanotubes without the introduction of strain. For ID systems on a cylindrical surface, translational symmetry with a screw axis could affect the electronic structure and related properties. The exotic electronic properties of ID carbon nanotubes are seen to arise predominately from intralayer interactions, rather than from interlayer interactions between multilayers within a single carbon nanotube or between two different nanotubes. Since the symmetry of a single nanotube is essential for understanding the basic physics of carbon nanotubes, most of this article focuses on the symmetry properties of single layer nanotubes, with a brief discussion also provided for two-layer nanotubes and an ordered array of similar nanotubes. 

Tangney et al.92 studied the friction between an inner and an outer carbon nanotube. Realistic potentials were used for the interactions within each nanotube and LJ potentials were employed to model the dispersive interactions between nanotubes. The intra-tube interaction potentials were varied and for some purposes even increased by a factor of 10 beyond realistic para-meterizations, thus artificially favoring the onset of instabilities and friction. Two geometries were studied, one in which inner and outer tubes were commensurate and one in which they were incommensurate. 

Hsu, C.-Y., et ah, Supersensitive, ultrafast, and broad-band tight-harvesting scheme employing carbon nanotube/Ti02 core-shell nanowire geometry. ACS Nano, 2012. 6(8) p. 6687-6692. 

The discovery of fullerenes in 1985 led to the era of nanomaterials.1 The three-dimensional geometry of these molecules as well as their unique properties distinguishes them from conventional molecules encountered in organic chemistry. Due to recent discoveries in this field, the horizons of this area have broadened to encompass various new molecules such as endohedral fullerenes, nanotubes, carbon nanohorns, and carbon nano-onions. This chapter discusses the electrochemical behavior of some of these carbon nanoparticles with special emphasis on endohedral fullerenes. Since a large number of fullerene derivatives have been prepared and their various electrochemical studies in different solvents and electrolytes have been reported, the electrochemistry of these derivatives is beyond the scope of this text.2 3 Among the other carbon nanoparticles, the electrochemistry of derivatives of carbon nanotubes has been reported. These studies have been highlighted in the final part of the chapter. 

Recently various kinds of porous materials have been developed and their properties and structures have been gathering great concerns in science. There are two types of pores of intraparticle pores and interparticle ones[l]. The intraparticle pores are in the primary particle itself, while the interparticle pores originate from the interparticle void spaces. Zeolites are the most representative porous solids whose pores come from the structurally intrinsic intraparticle pores. The pore geometry can be evaluated by their crystallographic data. The carbon nanotube of which pore wall is composed of graphitic sheets is also the... 

Summary. The interplay between electrical and mechanical properties of suspended, doubly clamped carbon nanotubes in the Coulomb blockade regime is studied theoretically. In this geometry, the capacitance between the nanotube and the gate depends on the distance between them. We find that the tube position changes in discrete steps every time an electron tunnels onto it. Edges of Coulomb diamonds acquire a (small) curvature. Eigenffequencies are modified by Coulomb blockade in a discrete fashion. 

Recent advances in theoretical methods and high-performance computing allow for reliable first principle calculations of complex nanostructures. Nanostructured materials are characterized by a fascinating diversity of geometries, but here we restrict ourselves mainly to first-principle calculations for nanoparticles and clusters, nanowires and nanocontacts. Nanoscale multilayers are also discussed very briefly, although multilayers are often considered as a subfield of thin-film physics rather than nanoscience. We also ignore nanotubes, because most of the work in this direction has been done on nonmagnetic carbon nanotubes. 

Abstract. At this paper novel low temperature (temperature 500°C) deposition method for preparation of the carbon nanotubes cathodes is represented. This method allows to use a glass as cathode substrate. Investigated samples differ by geometry of deposited layer of the carbon nanotubes with complete cover and cover with islands of different diameters. 

Keywords carbon nanotubes, defects and vacancies, geometry and electronic structures, semi-empirical quantum calculations. 

Many materials exist that have dimensions in the range of 1 rnn to several micrometers. Recall that colloidal particles (e.g., latex particles from emulsion polymerization, colloidal silica or alumina, etc.) fall in the range from about 10 nm to 1000 nm (1 jxm). A few examples of nanoparticles that are designed with more specific structures or geometries include carbon nanotubes, metal clusters, nanoscale magnetic crystals, and semiconducting ... 

This chapter discusses the fundamental principles for designing nanoporous adsorbents and recent progress in new sorbent materials. For sorbent design, detail discussion is given on both fundamental interaction forces and the effects of pore size and geometry on adsorption. A summary discussion is made on recent progress on the following types of materials as sorbents activated carbon, activated alumina, silica gel, MCM-41, zeolites, n -complexation sorbents, carbon nanotubes, heteropoly compounds, and pillared clays. 2001 Academic Press. 

The goal of this book is to summarize the recent advances in carbon nanotubes as a new material for electrochemical sensors. Since their discoveiy in 1991, carbon nanotubes have received considerable attention in different fields. Their speeial geometry and unique electronic, mechanical, chemical and thermal properties make them a very attractive material for the design of electrochemical biosensors. 

During the last years, a growing interest in the creation of micro- and nanoelectronic devices by use of the swift heavy ion track technology in a combination with carbon nanotubes (CNTs) is observed in several research centers worldwide. The CNTs were grown in etched ion tracks in Si02 layers on Si. For this purpose, Ni-catalyst nanoclusters were electrochemically deposited within the ion tracks. The geometry of the obtained nanostructures has been analyzed. Structure features of CNTs obtained by themial chemical vapor deposition have been investigated. 

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