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Terms modified by CNT Selected AbstractsAutomated image-based phenotypic analysis in zebrafish embryosDEVELOPMENTAL DYNAMICS, Issue 3 2009Andreas Vogt Abstract Presently, the zebrafish is the only vertebrate model compatible with contemporary paradigms of drug discovery. Zebrafish embryos are amenable to automation necessary for high-throughput chemical screens, and optical transparency makes them potentially suited for image-based screening. However, the lack of tools for automated analysis of complex images presents an obstacle to using the zebrafish as a high-throughput screening model. We have developed an automated system for imaging and analyzing zebrafish embryos in multi-well plates regardless of embryo orientation and without user intervention. Images of fluorescent embryos were acquired on a high-content reader and analyzed using an artificial intelligence-based image analysis method termed Cognition Network Technology (CNT). CNT reliably detected transgenic fluorescent embryos (Tg(fli1:EGFP)y1) arrayed in 96-well plates and quantified intersegmental blood vessel development in embryos treated with small molecule inhibitors of anigiogenesis. The results demonstrate it is feasible to adapt image-based high-content screening methodology to measure complex whole organism phenotypes. Developmental Dynamics 238:656,663, 2009. © 2009 Wiley-Liss, Inc. [source] Tris(2,2,-bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Platinized Carbon Nanotube,Zirconia,Nafion Composite FilmsELECTROANALYSIS, Issue 12 2010Hyun Yoon Abstract Mesoporous films of platinized carbon nanotube,zirconia,Nafion composite have been used for the immobilization of tris(2,2,-bipyridyl)ruthenium (II) (Ru(bpy)32+) on an electrode surface to yield a solid-state electrogenerated chemiluminescence (ECL) sensor. The composite films of Pt,CNT,zirconia,Nafion exhibit much larger pore diameter (3.55,nm) than that of Nafion (2.82,nm) and thus leading to much larger ECL response for tripropylamine (TPA) because of the fast diffusion of the analyte within the films. Due to the conducting and electrocatalytic features of CNTs and Pt nanoparticles, their incorporation into the zirconia,Nafion composite films resulted in the decreased electron transfer resistance within the films. The present ECL sensor based on the Pt,CNT,zirconia,Nafion gave a linear response (R2=0.999) for TPA concentration from 3.0,nM to 1.0,mM with a remarkable detection limit (S/N=3) of 1.0,nM, which is much lower compared to those obtained with the ECL sensors based on other types of sol-gel ceramic,Nafion composite films such as silica,Nafion and titania,Nafion. [source] Voltammetric Reduction of a 4-Nitroimidazole Derivative on a Multiwalled Carbon Nanotubes Modified Glassy Carbon ElectrodeELECTROANALYSIS, Issue 13 2008P. Jara-Ulloa Abstract We report the electrochemical behavior of a 4-nitroimidazole derivative, 1-methyl-4-nitro-2-hydroxymethylimidazole (4-NImMeOH), on glassy carbon electrode (GCE) modified with multiwalled carbon nanotubes (MWCNT). As dispersing agents, dimethylformamide (DMF) and water were used. The electrochemical response of the resulting electrodes was evaluated using linear sweep, cyclic and square-wave voltammetry (LSV, CV and SWV). Several parameters such as medium pH, nature and concentration of the CNTs dispersion and accumulation time were tested. The optimal conditions determined for obtain better response were: pH,2, dispersion concentration=4,mg/mL of CNT in water, accumulation time=7,min. The MWCNT-modified GCE exhibited attractive electrochemical properties producing enhanced currents with a significant reduction in the overpotential and good signal-to-noise characteristics, in comparison with the bare GCE. The modified electrode is highly repeatable for consecutive measurements, reaching a variation coefficient of 2.9% for ten consecutive runs. [source] Electrooxidation of DNA at Glassy Carbon Electrodes Modified with Multiwall Carbon Nanotubes Dispersed in ChitosanELECTROANALYSIS, Issue 7-8 2007Soledad Bollo Abstract We report on the analytical performance of glassy carbon (GCE) electrodes modified with a dispersion of multiwall carbon nanotubes (CNT) in chitosan (CHIT) for the quantification of DNA. The electroanalytical response of the resulting electrodes was evaluated using differential pulse voltammetry, while the electrochemical reactivity of the film surface was characterized using scanning electrochemical microscopy. Different treatments of the modified GCE were evaluated to improve the stability of the film and the accumulation of DNA. The guanine oxidation signal of double stranded calf-thymus DNA after 3-min accumulation was 20 times higher at GCE/CHIT-CNT cross-linked with glutaraldehyde (GTA) than at bare GCE, while the peak potential was around 45,mV less positive. The guanine oxidation signal demonstrated to be highly reproducible, with 3.4% RSD for 5 different electrodes. The treatment with sodium hydroxide demonstrated to be not effective since the resulting films were less stable and the guanine oxidation signal was ten times smaller compared to electrodes prepared with the GTA treated films. The effect of chitosan molecular weight used to prepare the dispersion and the amount of carbon nanotubes dispersed were evaluated. The response of single stranded DNA and oligo(dG)15 is also discussed. [source] Reagentless Glucose Biosensor Based on the Direct Electrochemistry of Glucose Oxidase on Carbon Nanotube-Modified ElectrodesELECTROANALYSIS, Issue 11 2006Xiliang Luo Abstract The direct electrochemistry of glucose oxidase (GOD) was revealed at a carbon nanotube (CNT)-modified glassy carbon electrode, where the enzyme was immobilized with a chitosan film containing gold nanoparticles. The immobilized GOD displays a pair of redox peaks in pH,7.4 phosphate buffer solutions (PBS) with the formal potential of about ,455,mV (vs. Ag/AgCl) and shows a surface-controlled electrode process. Bioactivity remains good, along with effective catalysis of the reduction of oxygen. In the presence of dissolved oxygen, the reduction peak current decreased gradually with the addition of glucose, which could be used for reagentless detection of glucose with a linear range from 0.04 to 1.0,mM. The proposed glucose biosensor exhibited high sensitivity, good stability and reproducibility, and was also insensitive to common interferences such as ascorbic and uric acid. The excellent performance of the reagentless biosensor is attributed to the effective enhancement of electron transfer between enzyme and electrode surface by CNTs, and the biocompatible environment that the chitosan film containing gold nanoparticles provides for immobilized GOD. [source] Carbon-Nanotube Based Electrochemical Biosensors: A ReviewELECTROANALYSIS, Issue 1 2005Joseph Wang Abstract This review addresses recent advances in carbon-nanotubes (CNT) based electrochemical biosensors. The unique chemical and physical properties of CNT have paved the way to new and improved sensing devices, in general, and electrochemical biosensors, in particular. CNT-based electrochemical transducers offer substantial improvements in the performance of amperometric enzyme electrodes, immunosensors and nucleic-acid sensing devices. The greatly enhanced electrochemical reactivity of hydrogen peroxide and NADH at CNT-modified electrodes makes these nanomaterials extremely attractive for numerous oxidase- and dehydrogenase-based amperometric biosensors. Aligned CNT "forests" can act as molecular wires to allow efficient electron transfer between the underlying electrode and the redox centers of enzymes. Bioaffinity devices utilizing enzyme tags can greatly benefit from the enhanced response of the biocatalytic-reaction product at the CNT transducer and from CNT amplification platforms carrying multiple tags. Common designs of CNT-based biosensors are discussed, along with practical examples of such devices. The successful realization of CNT-based biosensors requires proper control of their chemical and physical properties, as well as their functionalization and surface immobilization. [source] Carbon nanotube/poly(methyl methacrylate) composite electrode for capillary electrophoretic measurement of honokiol and magnolol in Cortex Magnoliae OfficinalisELECTROPHORESIS, Issue 16 2006Xiao Yao Abstract This paper describes the development and the application of a novel carbon nanotube/poly(methyl methacrylate) (CNT/PMMA) composite electrode as a sensitive amperometric detector of CE. The composite electrode was fabricated on the basis of the in,situ polymerization of a mixture of CNT and prepolymerized methylmethacrylate in the microchannel of a piece of fused-silica capillary under heat. The performance of this unique system has been demonstrated by separating and detecting honokiol and magnolol in traditional Chinese medicine, Cortex Magnoliae Officinalis. Factors influencing their separation and detection processes were examined and optimized. Honokiol and magnolol were well separated within 7,min in a 40 cm long capillary at a separation voltage of 15,kV using a 50 mM borate buffer (pH,9.2). The new CNT-based CE detector offered significantly lower operating potentials, yielded substantially enhanced S/N characteristics, and exhibited resistance to surface fouling and hence enhanced stability. It demonstrated long-term stability and reproducibility with RSDs of less than 5% for the peak current (n = 9) and should also find a wide range of applications in microchip CE, flowing injection analysis, and other microfluidic analysis systems. [source] An Atomic and Mesoscopic Study of Precipitation Kinetics in Al-Zr-Sc Alloys,ADVANCED ENGINEERING MATERIALS, Issue 12 2006E. Clouet This study illustrates how a quantitative multiscale modelling of the precipitation kinetics can be performed. Using a very limited number of experimental data and ab-initio calculations, we built for the Al-Zr-Sc alloy an atomic model from which mesoscopic quantities like the interface free energy or the nucleation free energy could be deduced. For the two binary Al-Zr and Al-Sc alloys, it was shown that a good agreement can be obtained between the KMC simulations, different mesoscopic models (CD and CNT) and experimental data. For the ternary alloy, CNT could be extended leading to predictions of an increase of the nucleation rate in agreement with atomic simulations and with experimental data. [source] Reconciling the Classical Nucleation Theory and Atomic Scale Observations and Modeling,ADVANCED ENGINEERING MATERIALS, Issue 12 2006G. Martin Here the author recalls the classical assumptions and the resulting expressions to be used in Cluster Dynamics stricto sensu and then, he shows how to establish a precise formal link between Classical Nucleation Theory (CNT) and Cluster Dynamics (CD). [source] Fracture behaviour of cracked carbon nanotube-based polymer composites: Experiments and finite element simulationsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 2 2010Y. KURONUMA ABSTRACT This paper studies the fracture behaviour of cracked carbon nanotube (CNT)-based polymer composites by a combined numerical,experimental approach. Tensile tests were conducted on single-edge cracked plate specimens of CNT/polycarbonate composites at room temperature and liquid nitrogen temperature (77 K), and the critical loads for fracture instabilities were determined. Elastic,plastic finite element simulations of the tests were then performed to evaluate the,J -integrals corresponding to the experimentally determined critical loads. Scanning electron microscopy examinations were also made on the specimen fracture surfaces, and the fracture mechanisms of the CNT-based composites were discussed. [source] Towards Efficient Dispersion of Carbon Nanotubes in Thermotropic Liquid CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Stefan Schymura Abstract Motivated by numerous recent reports indicating attractive properties of composite materials of carbon nanotubes (CNTs) and liquid crystals (LCs) and a lack of research aimed at optimizing such composites, the process of dispersing CNTs in thermotropic LCs is systematically studied. LC hosts can perform comparably or even better than the best known organic solvents for CNTs such as N -methyl pyrrolidone (NMP), provided that the dispersion process and choice of LC material are optimized. The chemical structure of the molecules in the LC is very important; variations in core as well as in terminal alkyl chain influence the result. Several observations moreover indicate that the anisotropic nematic phase, aligning the nanotubes in the matrix, per se stabilizes the dispersion compared to a host that is isotropic and thus yields random tube orientation. The chemical and physical phenomena governing the preparation of the dispersion and its stability are identified, taking into account enthalpic, entropic, as well as kinetic factors. This allows a guideline on how to best design and prepare CNT,LC composites to be sketched, following which tailored development of new LCs may take the advanced functional material that CNT,LC composites comprise to the stage of commercial application. [source] A Closer Look Inside Nanotubes: Pore Structure Evaluation of Anodized Alumina Templated Carbon Nanotube Membranes Through Adsorption and Permeability StudiesADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Georgios Pilatos Abstract Although hollow nanostructures, such as nanotubes, represent a major portion of nanoscaled materials with a tremendously large application range, a detailed evaluation of their internal characteristics still remains elusive. Transmission electron microscopy is the most common analytical technique to examine the internal configuration of these structures, yet it can only provide evidence of a minimal portion of the overall material, thus, it cannot be accurately generalized. In the present paper, in addition to electron microscopy and other spot-size analysis methods (X-ray diffraction, Raman spectroscopy, etc.), a combination of techniques including adsorption, permeability, and relative permeability are employed in order to provide important insights into various crucial details of the overall internal surface and hollow-space characteristics of carbon nanotube (CNT) arrays and membranes. The CNT arrays are fabricated using anodized alumina as a template in a flow-through chemical vapor deposition (CVD) reactor. This is the first systematic approach for investigating the internal configuration of template-based CNT arrays in detail. Key findings are made for the customized optimization of the resulting nanotube membranes for a variety of applications, including separations, nanofluidics and nanoreactors, biological capturing and purification, and controlled drug delivery and release. [source] Nanowires: A General Electrochemical Strategy for Synthesizing Charge-Transfer Complex Micro/Nanowires (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 8 2010Mater. A general electrochemical strategy for synthesizing charge-transfer complex micro-/nanowires utilizing a carbon nanotube (CNT) electrode is demonstrated by Z. Liu and co-workers on page 1209. The background scanning electron microscopy image depicts high-quality AgTCNQ nanowires grown from a CNT electrode. The uniform and high-aspect-ratio nature of thus-grown charge-transfer complex micro-/nanowires intrinsically originates from the specific features of CNTs in terms of one-dimensional structure and ultrasmall surface area with few or no defects. [source] A General Electrochemical Strategy for Synthesizing Charge-Transfer Complex Micro/NanowiresADVANCED FUNCTIONAL MATERIALS, Issue 8 2010Liang Ren Abstract Universal strategies for synthesizing one-dimensional organic nanomaterials are of fundamental importance in the development of more flexible, cheaper and lighter electronics. Charge-transfer (CT) complexes, the major kind of organic conductors, are in the long-term attractive materials owing to their unique crystal structures and conductive properties. In this article, a general strategy for the synthesis of CT complex micro/nanowires based on the localized nanoelectrochemistry using tiny carbon nanotube (CNT) electrodes is presented. This strategy is successfully demonstrated over 12 typical CT complexes, and a general rule for the preparation of various kinds of CT complex micro/nanowires is summarized. The CT complex micro/nanowires thus synthesized have high aspect ratios and long lengths as compared with traditional macroscopic planar electrodes, originating from the one-dimensional structural feature with fewer or no defects and the ultrasmall surface area of the CNT. This work provides a more versatile material basis for the fundamental and application studies of low-dimensional organic conductor materials. [source] Laser-Induced Rapid Carbon Nanotube Micro-ActuatorsADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Zhi Han Lim Abstract Laser-induced rapid actuating microstructures made of aligned carbon nanotube (CNT) arrays are achieved. Desirable operational features of the CNT micro-actuators include low laser power activation, rapid response, elastic and reversible motion, and robust durability. Experimental evidence suggests a laser-induced electrostatic interaction mechanism as the primary cause of the optomechanical phenomenon. Oscillating CNT micro-actuators up to 40,kHz are achieved by driving them with a modulated laser beam. The micro-actuators are utilized in exerting a sub-micro-Newton force to bend nanowires. Electrical coupling of the micro-actuator and feasibilities of multi-actuator systems made entirely out of CNTs are also demonstrated. [source] Restorable Type Conversion of Carbon Nanotube Transistor Using Pyrolytically Controlled Antioxidizing Photosynthesis CoenzymeADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Bo Ram Kang Abstract Here, a pyrolytically controlled antioxidizing photosynthesis coenzyme, , -Nicotinamide adenine dinucleotide, reduced dipotassium salt (NADH) for a stable n-type dopant for carbon nanotube (CNT) transistors is proposed. A strong electron transfer from NADH, mainly nicotinamide, to CNTs takes place during pyrolysis so that not only the type conversion from p-type to n-type is realized with 100% of reproducibility but also the on/off ratio of the transistor is significantly improved by increasing on-current and/or decreasing off-current. The device was stable up to a few months with negligible current changes under ambient conditions. The n-type characteristics were completely recovered to an initial doping level after reheat treatment of the device. [source] Beam to String Transition of Vibrating Carbon Nanotubes Under Axial TensionADVANCED FUNCTIONAL MATERIALS, Issue 11 2009Xianlong Wei Abstract State-of-the-art nanoelectromechanical systems have been demonstrated in recent years using carbon nanotube (CNT) based devices, where the vibration of CNTs is tuned by tension induced through external electrical fields. However, the vibration properties of CNTs under axial tension have not been quantitatively determined in experiments. Here, a novel in situ method for precise and simultaneous measurement of the resonance frequency, the axial tension applied to individual CNTs and the tube geometry is demonstrated. A gradual beam-to-string transition from multi-walled CNTs to single-walled CNTs is observed with the crossover from bending rigidity dominant regime to extensional rigidity dominant regime occur much larger than that expected by previous theoretical work. Both the tube resonance frequency under tension and transition of vibration behavior from beam to string are surprisingly well fitted by the continuum beam theory. In the limit of a string, the vibration of a CNT is independent of its own stiffness, and a force sensitivity as large as 0.25,MHz (pN),1 is demonstrated using a 2.2,nm diameter single-walled CNT. These results will allow for the designs of CNT resonators with tailored properties. [source] High-Conductivity Polymer Nanocomposites Obtained by Tailoring the Characteristics of Carbon Nanotube Fillers,ADVANCED FUNCTIONAL MATERIALS, Issue 20 2008Nadia Grossiord Abstract We present a detailed study of the influence of carbon nanotube (CNT) characteristics on the electrical conductivity of polystyrene nanocomposites produced using a latex-based approach. We processed both industrially-produced multi-wall CNT (MWCNT) powders and MWCNTs from vertically-aligned films made in-house, and demonstrate that while the raw CNTs are individualized and dispersed comparably within the polymer matrix, the electrical conductivity of the final nanocomposites differs significantly due to the intrinsic characteristics of the CNTs. Owing to their longer length after dispersion, the percolation threshold observed using MWCNTs from vertically-aligned films is five times lower than the value for industrially-produced MWCNT powders. Further, owing to the high structural quality of the CNTs from vertically-aligned films, the resulting composite films exhibit electrical conductivity of 103,S m,1 at 2,wt% CNTs. On the contrary, composites made using the industrially-produced CNTs exhibit conductivity of only tens of S m,1. To our knowledge, the measured electrical conductivity for CNT/PS composites using CNTs from vertically-aligned films is by far the highest value yet reported for CNT/PS nanocomposites at this loading. [source] Template Synthesis of Aligned Carbon Nanotube Arrays using Glucose as a Carbon Source: Pt Decoration of Inner and Outer Nanotube Surfaces for Fuel-Cell Catalysts,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2008Zhenhai Wen A facile method is developed to synthesize aligned arrays of open-ended carbon nanotubes (CNTs) via in situ glucose polymerization in the inner pores of anodic aluminum oxide templates under hydrothermal conditions, followed by carbonization at high temperature. Pt nanoparticles are decorated on the surfaces of the as-prepared CNTs using the incipient wet method based on the use of NaBH4 as a reductant. Characterization of the resulting structures by transmission electron microscopy and field-emission scanning electron microscopy demonstrates that the Pt nanoparticles are anchored on both the inner and outer walls of CNTs, thus giving rise to a shell,core,shell-like nanotube composite. The electrocatalytic properties of the Pt,CNT,Pt electrodes are investigated for methanol oxidation by cyclic voltammetry and chronoamperometric measurements. It is found that the hybrid electrodes show superior catalytic performance compared to commercial carbon-black-supported Pt. The increased catalytic efficiency of Pt might be a result of the unique morphology of these structures. [source] Carbon Nanotube Coatings on Bioglass-Based Tissue Engineering ScaffoldsADVANCED FUNCTIONAL MATERIALS, Issue 15 2007R. Boccaccini Abstract The coating of highly porous Bioglass® based 3D scaffolds with multi-walled carbon nanotubes (CNT) was investigated. Foam like Bioglass® scaffolds were fabricated by the replica technique and electrophoretic deposition was used to deposit homogeneous layers of CNT throughout the scaffold pore structure. The optimal experimental conditions were determined to be: applied voltage 15,V and deposition time 20 minutes, utilizing a concentrated aqueous suspension of CNT with addition of a surfactant and iodine. The scaffold pore structure remained invariant after the CNT coating, as assessed by SEM. The incorporation of CNTs induced a nanostructured internal surface of the pores which is thought to be beneficial for osteoblast cell attachment and proliferation. Bioactivity of the scaffolds was assessed by immersion studies in simulated body fluid (SBF) for periods of up to 2 weeks and the subsequent determination of hydroxyapatite (HA) formation. The presence of CNTs can enhance the bioactive behaviour of the scaffolds since CNTs can serve as template for the ordered formation of a nanostructured HA layers, which does not occur on uncoated Bioglass® surfaces. [source] Shaping Carbon Nanotubes and the Effects on Their Electrical and Mechanical Properties,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2006S. Wang Abstract A method is developed and shown to be able to shape a carbon nanotube (CNT) into a desired morphology while maintaining its excellent electrical and mechanical properties. Single, freestanding nanotubes are bent by a scanning tunneling microscopy probe, and their morphology is fixed by electron-beam-induced deposition (inside a transmission electron microscope) of amorphous carbon on the bent area. It is shown that the mechanical strength of the bent CNT may be greatly enhanced by increasing the amount of carbon glue or the deposition area, and the electrical conduction of the nanotube shows hardly any dependence on the bending deformation or on the deposition of amorphous carbon. Our findings suggest that CNTs might be manipulated and processed as interconnections between electronic devices without much degradation in their electrical conductance, and be used in areas requiring complex morphology, such as nanometer-scale transport carriers and nanoelectromechanical systems. [source] Cover Picture: Fabrication and Electrical and Mechanical Properties of Carbon Nanotube Interconnections (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 11 2005Mater. Abstract The fabrication of carbon nanotube (CNT) structures, including simple tube,tube connections, crossed junctions, T-junctions, zigzag structures, and even nanotube networks, has been achieved by cutting and soldering CNTs using electron-beam-induced deposition of amorphous carbon (a-C), as detailed in the work of Peng and co-workers on p.,1825. These CNT structures have been constructed with a high degree of control, and it is found that the electric conductance and mechanical strength of the junctions can be improved by the deposition of a-C and by increasing the contact area of the junctions. Individual carbon nanotubes (CNTs) have been cut, manipulated, and soldered via electron-beam-induced deposition of amorphous carbon (a-C) and using a scanning tunneling microscope inside a transmission electron microscope. All CNT structures, including simple tube,tube connections, crossed junctions, T-junctions, zigzag structures, and even nanotube networks, have been successfully constructed with a high degree of control, and their electrical and mechanical properties have been measured in situ inside the transmission electron microscope. It is found that multiple CNTs may be readily soldered together with moderate junction resistance and excellent mechanical resilience and strength, and the junction resistance may be further reduced by current-induced graphitization of the deposited a-C on the junction. [source] Continuous Multilayered Carbon Nanotube YarnsADVANCED MATERIALS, Issue 6 2010Xiao-Hua Zhong Kilometers of continuous multifunctional carbon nanotube (CNT) yarns have been spun directly from chemical vapor deposition synthesis. The CNT yarn consists of multiple layers of high-purity double-walled CNTs stacked in seamless tubules or folded films along the yarn axis (see image). This multilayerd CNT yarn is promising for applications as engineering fibers, composites, and intelligent fabrics. [source] Aligned Carbon Nanotubes with Ferromagnetic BehaviorADVANCED MATERIALS, Issue 4 2010Eleni C. Vermisoglou Magnetic carbon nanotube (CNT) arrays are grown by in situ encapsulation of ferromagnetic iron carbide nanoparticles within the tube walls (see figure). The resulting structures, combining the inherently unique characteristics of aligned and open-ended CNTs with the fact that magnetic functionality is provided from "inside the walls", are promising functional units in highly efficient flow systems, for example, as parallel magnetic nanoreactors and in biological separations. [source] Majority Carrier Type Conversion with Floating Gates in Carbon Nanotube TransistorsADVANCED MATERIALS, Issue 47 2009Woo Jong Yu A charge trapping layer can serve not only for designing multilevel nonvolatile memory but also for type conversion from p- to n-type and vice versa of carbon nanotube (CNT) channels. Type conversion from p- to n-type and vice versa for CNT field effect transistors can be realized by changing the polarity of trapped charges (see figure). [source] Electrochemical Synthesis of High-Quality AgTCNQ Nanowires Using Carbon Nanotube ElectrodesADVANCED MATERIALS, Issue 46 2009Liang Ren High-quality charge-transfer complex AgTCNQ nanowires have been successfully synthesized by a facile nanoelectrochemical approach utilizing carbon nanotube (CNT) electrodes. These nanowires have diameters of 30,80,nm and lengths of up to several tens of micrometers, and exhibit remarkable electrical switching bistability. The uniform and high aspect ratio nature of nanowires originates from the one-dimensional structural feature and ultrasmall surface area of the CNTs. [source] Shielding Nanowires and Nanotubes with Imogolite: A Route to NanocablesADVANCED MATERIALS, Issue 43 2009Agnieszka Kuc The use of an imogolite (aluminosilicate) sheath to protect a conducting core consisting of a carbon nanotube (CNT) or nanowire from mechanical and chemical attacks is proposed. The cross-sectional structure of such a nanocable is shown in the figure. The most stable CNT@ imogolite nanocable is calculated to have a tube,tube distance of 2.8,Å and an insertion energy of ca. 60,meV per carbon atom. [source] Thermomechanical and Thermal Contact Characteristics of Bismuth Telluride Films Electrodeposited on Carbon Nanotube ArraysADVANCED MATERIALS, Issue 42 2009Himanshu Mishra A scalable electrochemical process for addressing the thermomechanical compliance and contact resistance at metal/thermoelectric (M/TE) interfaces by integrating TE films with carbon nanotube (CNT) arrays is presented. Thermomechanical compliance and thermal contact characteristics of TE/CNT/M and TE/M contacts are compared. A process-flow for patterned electrodeposition of TE films on CNT arrays coated surfaces is also demonstrated. [source] Crinkling Ultralong Carbon Nanotubes into Serpentines by a Controlled Landing ProcessADVANCED MATERIALS, Issue 41 2009Yagang Yao Serpentine carbon nanotubes (CNTs) are successfully synthesized by controlling the landing of ultralong CNTs on a quartz surface. Several experimental parameters are investigated and the growth mechanism is further clarified (see figure). It is demonstrated that the high on/off ratio of single CNTs is maintained when serpentine CNTs are used to produce ultrahigh-current CNT-based devices. [source] Fast High-Temperature Response of Carbon Nanotube Film and Its Application as an Incandescent DisplayADVANCED MATERIALS, Issue 35 2009Peng Liu Super aligned carbon nanotube (CNT) film shows a fast high-temperature response: the film can be heated to incandescence and cools down in about 1 ms. Using screen printing and laser cutting, an incandescent CNT film array that can dynamically display Chinese characters is fabricated. More applications of the film may be developed based on its fast response. [source] | ||||||||||||||||||||||||||||||||||||||||