Zirconia nanotubes

Hollow nanotubes of zirconia as well as of yttria-stabilized zirconia are successfully prepared by first coating the carbon nanotubes appropriately with the oxidic material and then burning off the carbon of the template

Encapsulated Molecules in Carbon Nanotubes: Structure and Properties

We encapsulate a number of fullerenes inside single-walled carbon nanotubes (SWNTs) including La2@C80 and ErxSc3-xN@C80(x=0-3). The structural properties of these nanoscopic hybrid materials are described using high resolution transmission electron microscopy and electron diffraction. It is found that the encapsulated fullerenes selfassemble into long, one-dimensional chains. The thermal stability of these supramolecular assemblies are studied and large variations are found. The behavior is nominally consistent with the mass of the encapsulated metallofullerenes

Microstructure Effects on Electrochemical Characteristics for Plasma Spray Deposited LiFePO4 Films

The electrochemical behavior of composite electrodes used in Li ion batteries is influenced by factors such as microstructural characteristics (e.g. particle size, crystallinity, porosity etc.) and composition. For optimal performance of electrodes these factors are of utmost concern and serve as motivation for research in this field. In this report, we investigated LiFePO4 films synthesized by a novel plasma spray deposition method, which has capability for direct deposition of LiFePO4 films with carbon. This enables electrode characterizations to be carried out at the film level, without recourse to steps involving powder material handling. In this report microstructure and electrochemical properties of LiFePO4 films were investigated to elucidate their unique characteristics. Our studies show that factors such as porosity and microstructure of the films affect the electrochemical properties. The mechanical compression and thermal annealing experiments are shown to affect the electrochemical characteristics of LiFePO4 films. We show that annealing treatment leads to a drastic improvement in impedance and charge-discharge capacities for the LiFePO4 films. These treatments could serve to improve the electrode properties of porous film based materials for Li ion batteries and help us develop new film based materials for energy storage applications

Nitrogen-containing carbon nanotubes

Carbon nanotubes containing small amounts of nitrogen are produced by the pyrolysis of aza-aromatics such as pyridine, methylpyrimidine and triazine over cobalt nanoparticles in an Ar atmosphere; good yields of such nanotubes are obtained by carrying out the pyrolysis of a mixture of pyridine and Fe(CO)5 in flowing Ar+H2

Electrical and thermal properties of C\u3csub\u3e60\u3c/sub\u3e-filled single-wall carbon nanotubes

We report measurements of electrical resistivity, thermopower, and thermal conductivity of highly C60-filled single-wall carbon nanotubes and unfilled controls, from 1.5 to 300 K. The data suggest that the C60 chains provide additional conductive paths for charge carriers, increase the rate of phonon scattering, and block interior sites from sorbing other gas molecules

Association Between Angiographic Complications and Clinical Outcomes Among Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention An EARLY ACS (Early Glycoprotein IIb/IIIa Inhibition in Non–ST-Segment Elevation Acute Coronary Syndrome) Angiographic Substudy

ObjectivesThe goal of this analysis was to determine the association between intraprocedural complications and clinical outcomes among patients with high-risk non–ST-segment elevation acute coronary syndrome (NSTEACS) undergoing percutaneous coronary intervention (PCI).BackgroundAmong patients undergoing PCI for NSTEACS, the relationship between intraprocedural complications and clinical outcomes, independent of epicardial and myocardial perfusion, has not been well characterized.MethodsThe EARLY ACS (Early Glycoprotein IIb/IIIa Inhibition in Non–ST-Segment Elevation Acute Coronary Syndrome) trial enrolled 9,406 patients with high-risk NSTEACS undergoing an early invasive strategy. Of these, 1,452 underwent angiographic assessment in an independent core laboratory and did not have a myocardial infarction (MI) between enrollment and angiography. We assessed the relationship between abrupt closure, loss of side branch(es), distal embolization, and no-reflow phenomenon and 30-day clinical outcomes in these patients.ResultsOf the patients, 166 (11.4%) experienced an intraprocedural complication. Baseline clinical characteristics were similar between patients who did and did not have complications. The 30-day composite of death or MI was significantly higher among patients with an intraprocedural complication (28.3% vs. 7.8%, odds ratio [OR]: 4.68, 95% confidence interval [CI]: 3.2 to 7.0, p < 0.001). Individually, both mortality (3.0% vs. 0.9%, OR: 3.60, 95% CI: 1.2 to 10.5, p = 0.019) and MI (27.1% vs. 7.4%, OR: 4.66, 95% CI: 3.1 to 7.0, p < 0.001) were significantly increased. After adjusting for differences in post-PCI epicardial and myocardial perfusion, the association with 30-day death or MI remained significant.ConclusionsAmong high-risk NSTEACS patients undergoing an invasive strategy, the incidence of intraprocedural complications is high, and the occurrence of these complications is associated with worse clinical outcomes independent of epicardial and myocardial perfusion.(Early Glycoprotein IIb/IIIa Inhibition in Patients With Non–ST-segment Elevation Acute Coronary Syndrome [EARLY ACS]; NCT00089895

Quantum Interference Effects in Electronic Transport through Nanotube Contacts

Quantum interference has dramatic effects on electronic transport through nanotube contacts. In optimal configuration the intertube conductance can approach that of a perfect nanotube ($4e^2/h$). The maximum conductance increases rapidly with the contact length up to 10 nm, beyond which it exhibits long wavelength oscillations. This is attributed to the resonant cavity-like interference phenomena in the contact region. For two concentric nanotubes symmetry breaking reduces the maximum intertube conductance from $4e^2/h$ to $2e^2/h$. The phenomena discussed here can serve as a foundation for building nanotube electronic circuits and high speed nanoscale electromechanical devices

A New Route to Fluorescent SWNT/Silica Nanocomposites: Balancing Fluorescence Intensity and Environmental Sensitivity

We investigate the relationship between photoluminescence (PL) intensity and environmental sensitivity of surfactant-wrapped single walled carbon nanotubes (SWNTs). SWNTs were studied under a variety of conditions in suspension as well as encapsulated in silica nanocomposites, which were prepared by an efficient chemical vapor into liquids (CViL) sol-gel process. The dramatically improved silica encapsulation process described here has several advantages, including fast preparation and high SWNT loading concentration, over other encapsulation methods used to prepare fluorescent SWNT/silica nanocomposites. Further, addition of glycerol to SWNT suspensions prior to performing the CViL sol-gel process allows for the preparation of freestanding fluorescent silica xerogels, which to the best of our knowledge is the first report of such nanocomposites. Our spectroscopic data on SWNTs suspended in aqueous surfactants or encapsulated in silica show that achieving maximum PL intensity results in decreased sensitivity of SWNT emission response to changes imparted by the local environment. In addition, silica encapsulation can be used to "lock-in" a surfactant micelle structure surrounding SWNTs to minimize interactions between SWNTs and ions/small molecules. Ultimately, our work demonstrates that one should consider a balance between maximum PL intensity and the ability to sense environmental changes when designing new SWNT systems for future sensing applications