In situ study of carbon nanotube formation by C2H2 decomposition on an iron-based catalyst

The properties and formation of nanotubes have been extensively studied, but very few deal with the catalytic production mechanism of nanotubes. Two different techniques, thermogravimetric analysis and UV-Raman, have been applied to analyse the carbon deposition by catalysed decomposition of acetylene over an iron-based catalyst. The nature of the produced carbon materials depends on reaction temperature. Also, TEM allows identification of carbon nanotubes, encapsulated particles, and other nanostructures, while UV-Raman confirms its graphitic and graphite-like nature. (C) 2000 Elsevier Science Ltd. All rights reserved.

Kinetics of the selective reduction of NO with CH4 over an In-Fe2O3/HZSM-5 catalyst

A kinetic model presented for the selective reduction of NO with CH4 over an InFe2O3/HZSM-5 catalyst by considering the process as a combination of two simultaneous reactions: NO+O2CH4 (reaction 1) and O-2+CH4 (reaction 2). Linear regression calculation was employed to find the kinetic parameters. It was found that although the activation energies of the two reactions were almost identical, the reaction rate constants were dramatically different, namely, k(1)much greater than k(2), indicating that the NO+O-2+CH4 reaction was more preferable to take place on the In-Fe2O3/HZSM-5 catalyst as compared with the O-2+CH4 reaction.

Effects of prior heavy exercise on V(over dot)O-2 kinetics during heavy exercise are related to changes in muscle activity

Burnley, M., Doust, J.H., Ball, D. and Jones, A.M. (2002) Effects of prior heavy exercise on VO2 kinetics during heavy exercise are related to changes in muscle activity. Journal of Applied Physiology 93, 167-174. RAE2008

Influence of blood donation on O-2 uptake on-kinetics, peak O-2 uptake and time to exhaustion during severe-intensity cycle exercise in humans

Thatcher, Rhys, et al., 'Influence of blood donation on O-2 uptake on-kinetics, peak O-2 uptake and time to exhaustion during severe-intensity cycle exercise in humans', Experimental Physiology (2006) 91(3) pp.499-509 RAE2008

Time required for the restoration of normal heavy exercise Vo(2) kinetics following prior heavy exercise

Burnley, M., Doust, J. and Jones, A. (2006). Time required for the restoration of normal heavy exercise Vo(2) kinetics following prior heavy exercise. Journal of Applied Physiology. 101(5), pp.1320-1327 RAE2008

Secondary structure effects on DNA hybridization kinetics: a solution versus surface comparison

The hybridization kinetics for a series of designed 25mer probe�target pairs having varying degrees of secondary structure have been measured by UV absorbance and surface plasmon resonance (SPR) spectroscopy in solution and on the surface, respectively. Kinetic rate constants derived from the resultant data decrease with increasing probe and target secondary structure similarly in both solution and surface environments. Specifically, addition of three intramolecular base pairs in the probe and target structure slow hybridization by a factor of two. For individual strands containing four or more intramolecular base pairs, hybridization cannot be described by a traditional two-state model in solution-phase nor on the surface. Surface hybridization rates are also 20- to 40-fold slower than solution-phase rates for identical sequences and conditions. These quantitative findings may have implications for the design of better biosensors, particularly those using probes with deliberate secondary structure.

Carbon nanotube composites for electronic interconnect applications

Irish Research Council for Science, Engineering and Technology (Postgraduate scholarship Enterprise Partnership scheme in collaboration with Intel Ireland Ltd., funded under the National Development Plan)

Dissolution kinetics of octadecanethiolate monolayers electro-adsorbed on Au(1 1 1)

Monolayers of octadecanethiolate on Au(1 1 1) surface were formed under electrochemical control. The influence of the formation time on the reductive desorption process was studied by cyclic voltammetry and chronoamperometry. When the formation time is increased, the reductive desorption peak observed on the voltammograms is significantly shifted in the negative direction, while the cathodic charge is only slightly affected. This behaviour is attributed to a higher degree of organisation of the monolayers for longer formation times, highlighting the role of defect sites in promoting the dissolution. A good agreement was found between our experimental chronoamperograms and theoretical models describing the dissolution process by a shrinkage mechanism. It is demonstrated that a reorganisation process takes place, consisting in the merging of small condensed domains into larger ones. This annealing phenomenon is time and potential dependent, the largest condensed domains being obtained for the longest formation times and least negative potentials. © 2008 Elsevier B.V. All rights reserved.

Kinetics of anti-Campylobacter jejuni monomeric and polymeric immunoglobulin A1 and A2 responses in serum during acute enteritis.

The intensity and kinetics of the serum polymeric and monomeric immunoglobulin A1 (IgA1) and IgA2 antibody responses to Campylobacter jejuni were analyzed. A rapid and marked serum IgA antibody response involving both the monomeric and polymeric components of IgA was observed after C. jejuni infections. IgA antibodies reached a peak of activity in serum during week 2 after the first symptoms of enteritis, about 10 days before the peak of IgG activity. Polymeric IgA accounted for most of the anti-C. jejuni activity at the peak of the IgA response (median, 90%; range, 44 to 98%) but rapidly disappeared from serum over a few weeks. In contrast, the serum monomeric IgA antibody response was low and was maintained over a prolonged period of time. Anti-C. jejuni IgA detected in the serum of healthy blood donors was mainly monomeric (median, 83%; range, 17 to 94%). In both the patients and the positive controls, IgA1 was the predominant (greater than 85%) subclass involved, even when the IgA antibody response was mainly polymeric. Our results suggest that polymeric IgA antibody responses are linked to a strong or persisting antigenic stimulation or both. Polymeric IgA antibodies appear to be a potential marker of acute C. jejuni infections, and their determination could provide a useful tool for the serological diagnosis of recent C. jejuni infections.

Orthogonal orientation control of carbon nanotube growth.

Carbon nanotubes (CNTs) have attracted attention for their remarkable electrical properties and have being explored as one of the best building blocks in nano-electronics. A key challenge to realize such potential is the control of the nanotube growth directions. Even though both vertical growth and controlled horizontal growth of carbon nanotubes have been realized before, the growth of complex nanotube structures with both vertical and horizontal orientation control on the same substrate has never been achieved. Here, we report a method to grow three-dimensional (3D) complex nanotube structures made of vertical nanotube forests and horizontal nanotube arrays on a single substrate and from the same catalyst pattern by an orthogonally directed nanotube growth method using chemical vapor deposition (CVD). More importantly, such a capability represents a major advance in controlled growth of carbon nanotubes. It enables researchers to control the growth directions of nanotubes by simply changing the reaction conditions. The high degree of control represented in these experiments will surely make the fabrication of complex nanotube devices a possibility.