Transparent Carbon Nanotube Network for Efficient Electrochemiluminescence Devices

A carbon nanotube‐based electrode that combines transparency and good conductivity was used for the first time to develop an electrochemiluminescence (ECL) device. It resulted in an excellent material for ECL applications thanks to the very favorable overpotential of amine oxidation that represents the rate‐determining step for the signal generation in both research systems and commercial instrumentation. The use of carbon nanotubes resulted in a ten times higher emission efficiency compared with commercial transparent indium tin oxide (ITO) electrodes. Moreover, application of this material for proof‐of‐principle ECL imaging was demonstrated, in which micro‐beads were used to mimic a real biological sample in order to prove the possibility of obtaining single cell visualization.     

Metastable (1 × 2) and (1 × 3) reconstructions of Pd(110)

By adsorption and subsequent reduction of oxygen on Pd(110), metastable (1 × 2) and (1 × 3) reconstructed surfaces have been produced. Oxygen was not present after the reduction but a small amount of residual hydrogen (< 0.15 monolayers) remained. However this is not the origin of the reconstruction as adsorption of this amount of hydrogen on the clean surface did not cause reconstruction. The structures were stable up to ˜ 370 K, and at higher temperatures they reverted to (1 × 1). These results are compared with Rh(110) where similar reconstructions have been found.     

Auger lineshape analysis as a tool to study surface reactions: kinetics of the dissociation of NO on Rh(110)

We present a new method for following the kinetics of the dissociation of chemisorbed molecules, by Auger electron spectroscopy (AES) in the pulse counting mode. By following the time evolution of the Auger lineshape, it is possible to quantify the relative weight of the dissociated and undissociated chemisorbed species as a function of time. As an example, we have applied the method to the case of NO chemisorbed on rhodium (110). The high signal to noise ratio which can be obtained by AES in the pulse counting mode makes it possible to measure the kinetics with good accuracy, without affecting the reaction.     

Stereoisomeric sugar-derived indolizines as versatile building blocks: synthesis of enantiopure di- and tetrahydroxyindolizidines.

The synthesis of the sugar-derived (1S,2R,8aR)-1,2-di-O-isopropylidene-1,2,3,5,6,8a-hexahydro-5-oxoindolizine (8) and by analogy of the corresponding stereoisomers ent-8 and ent-7, an epimer at C2 of ent-8, has been accomplished in a straightforward manner. The carbon-carbon double bond and the carbonyl functionalities on the six-membered ring make these nitrogen-containing heterocycles useful building blocks for the efficient preparation of a variety of enantiopure polyhydroxylated indolizidines of interest for their glycosidase inhibitory activity. We report here the synthesis of 2,8a-diepilentiginosine 12 from 8 and the preparation of stereoisomeric 1,2,7,8-tetrahydroxyindolizidines 9-11 performed by OsO4-catalyzed double bond syn dihydroxylation of 7 and 8, followed by deoxygenation of the amide group.     

PVC chlorination using fluorine as initiator

The chlorination of PVC has been studied in a fluidized bed reactor, initiating the reaction with elementary fluorine. The reaction has been carried out at temperatures between 20° and 60° for various concentrations of chlorine and fluorine. The rate of reaction is given by the equation:

(1)$\text{x=}\text{k[}\text{Cl}{}_2\text{]}{}^{\mathrm{0·5}}\text{[}\text{F}{}_2\text{]t}\text{1+k[}\text{Cl}{}_2\text{]}{}^{\mathrm{0·5}}\text{[}\text{F}{}_2\text{]t}$

, temperature is given by

$\text{log}\text{k=}\text{3500}\text{4·57}\text{1}\text{T}\text{+0·707}$

.Equation (1) is satisfied also by data obtained from a small scale plant reactor. A reaction mechanism is proposed.     

Synchotron radiation photoemission study of adsorbate-induced 3d core level shifts of Pd(110)

The surface core level shifts of Pd(110) and oxygen and CO covered Pd(110) have been measured using synchrotron radiation. The results are consistent with values predicted using a Born-Haber cycle, confirming the usefulness of this approach. The largest shift occurs for the CO covered surface, indicating that initial state charge transfer does not dominate the shifts.     

Cyclic voltammetry and bulk electronic properties of soluble carbon nanotubes

The bulk electronic properties of pyrrolidine-functionalized nanotubes are obtained from cyclic voltammetry measurements and discussed in the light of quantum chemical calculations. The functionalization is found to preserve the metallic character and to hardly affect the average density of electronic states.     

Reconstruction of cosmic and beam-halo muons with the CMS detector

The powerful muon and tracker systems of the CMS detector together with dedicated reconstruction software allow precise and efficient measurement of muon tracks originating from proton-proton collisions. The standard muon reconstruction algorithms, however, are inadequate to deal with muons that do not originate from collisions. This note discusses the design, implementation, and performance results of a dedicated cosmic muon track reconstruction algorithm, which features pattern recognition optimized for muons that are not coming from the interaction point, i.e., cosmic muons and beam-halo muons. To evaluate the performance of the new algorithm, data taken during Cosmic Challenge phases I and II were studied and compared with simulated cosmic data. In addition, a variety of more general topologies of cosmic muons and beam-halo muons were studied using simulated data to demonstrate some key features of the new algorithm.