Hydrogen component fugacity in binary mixtures with carbon monoxide: Temperature dependence

The fugacity coefficients of hydrogen in binary mixtures with carbon monoxide were measured using a physical equilibrium technique. This technique involves the use of an experimental chamber which is divided into two regions by a semipermeable membrane through which hydrogen, but not carbon monoxide, can penetrate. Measurement of the gas pressures inside and outside of the membrane allows a direct measurement of the hydrogen component fugacity at a given temperature and binary mixture mole fraction. In this paper, results are reported at 130, 160, and 190°C. In each case, the total pressure of the mixture was maintained at a nominal value of 3.39 MPa. The general qualitative features of the data are discussed, and comparisons are made with predictions obtained from the Redlich-Kwong, Peng-Robinson-Soave, and extended corresponding-state models.     

Suspended carbon nanotube quantum wires with two gates

Suspended single-walled carbon nanotube devices comprised of high-quality electrical contacts and two electrostatic gates per device have been prepared. Compared to nanotubes pinned on substrates, the suspended devices exhibit little hysteresis related to environmental factors and act as cleaner Fabry-Perot interferometers or single-electron transistors. The high-field saturation currents in the suspended nanotubes related to optical phonon or zone-boundary phonon scattering are significantly lower due to the lack of efficient heat sinking. The multiple-gate design may also facilitate future investigations into the electromechanical properties of nanotube quantum systems.