One or more flow control modules, implemented on various types of network topologies, provide a number of functionalities for controlling the flow of IP packets over a network connection. The ceramic honeycomb articles possess a microstructure characterized by a unique combination of relatively high porosity between 42% and 56%, and relatively narrow pore size distribution wherein less than 15% of the total porosity has a pore diameter less than 10 \u03bcm, less than 20% of the total porosity has a pore diameter greater than 30 \u03bcm, and dbreadth\u22661. The dielectric coatings are prepared by admixing, in a solvent, a polymeric nitrogenous porogen with a high temperature, thermosetting host polymer miscible therewith, coating a substrate surface with the admixture, heating the uncured coating to cure the host polymer and provide a vitrified, two-phase matrix, and then decomposing the porogen. The tube may form part of the wand or the probe. In the semiconductor manufacturing apparatus, after the valve is opened, the purge gas is supplied to apply physical vibration due to shock wave in the processing chamber 100 so that deposits are detached therefrom to be monitored as particles.