An autosampler with a short transfer line for Curie point pyrolysis capillary gas chromatography

A new multichannel autosampler which can automatically analyze up to twenty samples in sequence has been developed for Curie point pyrolysis – capillary GC. Compared with a previous system [1] the transfer line between the pyroysis unit and chromatograph is shorter, and thus has less dead volume, and can be operated at a higher temperature (300 °C). The relative yields of higher boiling point, highly polar, and thermally labile pyrolysates generated from polymers, and the reproducibility, were better than those obtained from the previous autosampler. To facilitate rapid operation an additional flow controller is installed on the new device to shorten the time taken to purge air from the sampler.     

Photoluminescence and FT-IR studies of the dissociative adsorption of H2 on the active ZrO2 catalyst and its role in the hydrogenation of CO

Photoluminescence and FT-IR studies of the adsorption of H₂ on ZrO₂ catalysts have been performdd to clarify the true natuee of active surface sites for the activaiion of H₂ in connection with the CO — H₂ reaction on the catalyst. The results indicate that the coordinatively unsaturated surface sites with different coordination numbers are generated on the surfaces by evacuation at temperatures higher than 600 K. These surface sites of lower coordination play a significant role in the reversible and irreversible dissociative adsorption of H₂ on the active ZrO₂ catalyst. The former seems to act as active hydrogen species for the CO — H₂ reaction to form branched hydrocarbons on the ZrO₂ catalyst.     

Scanning tunneling microscopy luminescence from nanoscale surface of GaAs(1 1 0)

Scanning tunneling microscopy luminescence (STML) was induced from the nanometer scale surfaces of cleaved n-type and p-type GaAs(1 1 0) wafers by using of an ITO-coated optical fiber probe in an ultrahigh-vacuum chamber. The STML from n-type GaAs(1 1 0) surface was induced under negative sample bias when the applied bias exceeds a threshold voltage around −1.5 V. Whereas the STML from p-type GaAs(1 1 0) surface was induced under positive sample bias when the applied bias exceeds a threshold voltage around +1.5 V. The excitation energies at the threshold voltages are consistent with the band gap of GaAs (1.42 eV) at 295 K. The typical quantum efficiencies for n-type and p-type GaAs are about 3 × 10⁻⁵ and 2 × 10⁻⁴ photons/electron, respectively. The observed STML from are attributed to a radiative recombination of electron-hole pairs generated by a hole injection for n-type GaAs under negative sample bias and an electron injection for p-type GaAs under positive sample bias, respectively.     

Chemistry of heterocyclic compounds LV Platinum(O) complexes of heterocyclic acetylenes: Bis-Lithiation

Low temperature bis-metal—halogen exchange on a platinacyclic moietyis reported to occur without cleavage of the zero-valent platinumalkyne bond(s). The metallation procedure affords a convenient, mild route to metalate, dehalogenate, label, and/or functionalize metallacycles.     

A highly active Fe(I) catalyst for radical polymerisation and taming the polymerisation with iodine

A fast and controlled radical polymerisation of acrylates and acrylamides can be achieved with a combination of a highly active metal catalyst, Fe2Cp2(CO)4, and a mild radical scavenger, iodine, in the presence of an iodide initiator.