نتایج جستجو برای: nanotubes
تعداد نتایج: 29050 فیلتر نتایج به سال:
Carbon nanotubes are coated with a layer of copper by an electroless plating method. To prepare CuOrcarbon nanotubes, Curcarbon nanotubes are oxidized by heating to 1608C in air for 12 h. The lithium insertion properties of carbon and CuOrcarbon nanotubes are tested by an electrochemical method. Carbon nanotubes can reversibly store 700 mA h Li g carbon, while CuO in CuOrcarbon nanotubes can re...
In this work, we studied the electro-optical properties of high-aligned carbon nanotubes deposited at room temperature. For this, we used the High Density Plasma Chemical Vapor Deposition system. This system uses a new concept of plasma generation: a planar coil is coupled to an RF system for plasma generation. This was used together with an electrostatic shield, for plasma densification, there...
In this paper, (10, 0) zigzag nanotubes and (6, 6) armchair nanotubes are considered to investigate the effects of randomly distributed vacancy defects on mechanical behaviors of single-walled carbon nanotubes. A spatial Poisson point process is employed to randomly locate vacancy defects on nanotubes. Atomistic simulations indicate that the presence of vacancy defects result in reducing nanotu...
The symmetry properties of the single-walled BC(2)N nanotubes were investigated. All the BC(2)N nanotubes possess nonsymmorphic line groups. In contrast with the carbon and boron nitride nanotubes, armchair and zigzag BC(2)N nanotubes belong to different line groups, depending on the index n (even or odd) and the vector chosen. The number of Raman- active phonon modes is almost twice that of th...
Electronic and optoelectronic devices based on thin films of carbon nanotubes are currently limited by the presence of metallic nanotubes. Here we present a novel approach based on nanotube alkyl functionalization to physically remove the metallic nanotubes from such network devices. The process relies on preferential thermal desorption of the alkyls from the semiconducting nanotubes and the su...
Based on density functional calculations, we have found that axial compression can induce structural transitions between Au(n,n) and Au(2n,n) nanotubes. The corresponding energy barriers increase with n. Although Au(2n,n) nanotubes are energitically more stable, the energy difference between Au(n,n) and Au(2n,n) decreases with n. The structural transitions are believed to be unique in those nan...
In this paper, we investigate effects of vacancy defects on fracture of carbon nanotubes and carbon nanotube/ aluminum composites. Our studies show that even a one-atom vacancy defect can dramatically reduce the failure stresses and strains of carbon nanotubes. Consequently, nanocomposites, in which vacancy-defected nanotubes are embedded, exhibit different characteristics from those in which p...
Novel carbon nanotubes±metal±ceramic nanocomposite powders and dense materials have been prepared and their microstructure and mechanical properties have been investigated. After a brief review on the structure, synthesis and physical properties of carbon nanotubes, we describe an original catalytic method that produces ceramic±matrix composite powders that contain in situ grown nanotubes. The ...
STATEMENT OF PROBLEM Most fractures of dentures occur during function, primarily because of the flexural fatigue of denture resins. PURPOSE The purpose of this study was to evaluate a polymethyl methacrylate denture base material modified with multiwalled carbon nanotubes in terms of fatigue resistance, flexural strength, and resilience. MATERIAL AND METHODS Denture resin specimens were fab...
in this thesis, we exploit a simple and suitable method for immobilization of copper(ii) complex of 4?-phenyl-terpyridine on activated multi-walled carbon nanotubes [amwcnts-o-cu(ii)-phtpy]. this nanostructure was characterized by various physico-chemical techniques. to ensure the efficiency and fidelity of copper species, the implementation of three-component strategies in click-chemistry all...
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