A set of sensing coils to measure plasma position is described. The possibility of placing these coils outside a vacuum vessel (as a resistive shell) is considered by analyzing a feedback system for controlling otherwise unstable axisymmetric motion. A simple model was used to study the axisymmetric stability of a noncircular plasma surrounded by a conducting vacuum vessel and a feedback control system. Suitable choice of the various constants allowed a study of either horizontally or vertically unstable motion, either with or without an iron core and with various configurations for the vacuum vessel. Analytic expressions for the stability limits are derived, together with the specific response to a requested step displacement, giving the overshoot, steady-state error, decay times, and maximum power supply voltage. By suitably choosing an effective decay index both vertical and horizontal motion were studied. The results are applied to TEXT Upgrade (horizontal elongated, with iron core, horizontal unstable) using an effective decay index of -1 相似文献
Schottky barrier diodes have been integrated into on-chip rectangular waveguides. Two novel techniques have been developed to fabricate diodes with posts suitable for integration into waveguides. One technique produces diodes with anode diameters of the order of microns with post heights from 90 to 125 microns and the second technique produces sub-micron anodes with post heights around 20 microns. A method has been developed to incorporate these structures into a rectangular waveguide and provide a top contact onto the anode which could be used as an I.F. output in a mixer circuit. Devices have been fabricated and D.C. characterized. 相似文献
Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry (2D FT-ICR MS) allows data-independent fragmentation of all ions in a sample and correlation of fragment ions to their precursors through the modulation of precursor ion cyclotron radii prior to fragmentation. Previous results show that implementation of 2D FT-ICR MS with infrared multi-photon dissociation (IRMPD) and electron capture dissociation (ECD) has turned this method into a useful analytical tool. In this work, IRMPD tandem mass spectrometry of calmodulin (CaM) has been performed both in one-dimensional and two-dimensional FT-ICR MS using a top-down and bottom-up approach. 2D IRMPD FT-ICR MS is used to achieve extensive inter-residue bond cleavage and assignment for CaM, using its unique features for fragment identification in a less time- and sample-consuming experiment than doing the same thing using sequential MS/MS experiments.
An extremely rapid tool for continuous flow synthetic process optimisation is described. A microfluidic reaction system operating in continuous flow is used in conjunction with confocal Raman microscopy to afford rapid molecule synthesis and product quantitation. Accordingly, the approach allows for rapid reaction optimisation within a continuous flow system. Specifically, the catalytic oxidation of isopropyl alcohol (IPA) to acetone using tetra-N-propylammonium perruthanate (TPAP)/N-methylmorpholine N-oxide (NMO) in a radial interdigitated micromixer is studied as a model reaction system. The composition of the reaction effluent can be determined with great facility and information relating to catalyst/co-oxidant ratios, catalyst turnovers and reaction endpoints extracted. Specifically, variation of catalyst and co-oxidant volumetric flow rates between 0 and 50 microL min(-1) is used to vary reactant concentrations, define reaction residence times and control product conversions between 0 and 100%. The rapid nature of the system allows chemical information to be gathered and utilised on a sub-minute timescale. 相似文献
