120,130 research outputs found
Modified CVD of nanoscale structures in and EVD of thin layers on porous ceramic membranes
Experiments on the modified chemical vapour deposition (CVD) and the electrochemical vapour deposition (EVD) of yttria-stabilized zirconia on porous substrates are reported. It is shown that, in the CVD stage, deposition occurs in a small (<20 um) region at the edge of the substrate, very likely leading to pore narrowing. This result illustrates the feasibility of the CVD technique for the modification of ceramic membranes to the (sub)nanometer scale. Film growth in the EVD stage is shown to be controlled by the inpore diffusion of the oxygen source reactant for short (<5 h) deposition times. The yttria to zirconia ratio in the deposited film is determined by the ratio present in the vapour phase. Very thin (<2 um) films can be deposited, which have a potential application in solid oxide fuel cells
Path Integral Solution by Sum Over Perturbation Series
A method for calculating the relativistic path integral solution via sum over
perturbation series is given. As an application the exact path integral
solution of the relativistic Aharonov-Bohm-Coulomb system is obtained by the
method. Different from the earlier treatment based on the space-time
transformation and infinite multiple-valued trasformation of
Kustaanheimo-Stiefel in order to perform path integral, the method developed in
this contribution involves only the explicit form of a simple Green's function
and an explicit path integral is avoided.Comment: 13 pages, ReVTeX, no figure
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