Flux-dependent shot noise through an Aharonov-Bohm interferometer with an embedded quantum dot

Shot noise through a closed Aharonov-Bohm interferometer carrying a quantum dot in one of its two current paths is investigated. It is found that the shot noise can be modulated by the magnetic flux Phi, the dot level, and the direct tunneling. Due to the interference between the two transmission channels, the Kondo correlation manifests itself in the flux dependence of the shot noise, which exhibits oscillation behavior with a period of Phi(0)/2 (Phi(0) is the flux quantum) for small voltages below the Kondo temperature T-K. At voltages well above T-K or outside the Kondo regime, the shot noise is determined by high-energy Coulomb and hybridization processes, and its Aharonov-Bohm oscillations restore the fundamental period of Phi(0). As a result of its two-particle nature, the shot noise contains higher-order harmonics absent in the current, demonstrating the fact that the noise is more sensitive to the effects of quantum interference than the current.

Methanol synthesis from CO2 using a silicone rubber/ceramic composite membrane reactor

A one-dimensional isothermal pseudo-homogeneous parallel flow model was developed for the methanol synthesis from CO2 in a silicone rubber/ceramic composite membrane reactor. The fourth-order Runge-Kutta method was adopted to simulate the process behaviors in the membrane reactor. How those parameters affect the reaction behaviors in the membrane reactor, such as Damkohler number Da, pressure ratio p(r), reaction temperature T, membrane separation factor alpha, membrane permeation parameter phi , as well as the non-uniform parameter of membrane permeation L-1, were discussed in detail. Parts of the theoretical results were tested and verified; the experimental results showed that the conversion of the main reaction in the membrane reactor increased by 22% against traditional fixed bed reactor, and the optimal non-uniform parameter of membrane permeation rate, L-1.opt ,does exist. (C) 2003 Elsevier B.V All rights reserved.

The effects of CO2 addition on the partial oxidation of heptane for hydrogen generation

The effects of CO2 on the partial oxidation of heptane for hydrogen generation have been studied. Based on the experimental results and thermodynamic equilibrium calculations, the validity of CO2 addition to weaken the hot spots, and the feasibility of the autothermal operation are discussed.