14,934 research outputs found
Integrated Parylene LC-ESI on a Chip
Full text linkIn this thesis, several microfluidic devices will be introduced to demonstrate the integration capability of a multilayer parylene surface micromachining technology. Due to its flexibility and versatility, various devices have been developed and integrated onto a single ship. Based on the technology, on-chip LC-ESI was successfully demonstrated.
Based on the technology, an electrostatically actuated micro peristaltic pump has been developed. An AC actuation voltage combined with a peristaltic actuation was used to demonstrate fluid pumping. A reasonable flow rate and pumping pressure were achieved. The pump dynamics and performance were then addressed further by an analysis based on a lumped-parameter model of the system.
Based on the same technology, an entirely surface micromachined electrostatically actuated valve has been demonstrated. A thermal flow sensor was integrated with the valve to be used for feedback control. Two modes, actuation voltage adjustment and PWM were investigated in characterizing the valve to control air flow. The testing results show that PWM has better linearity and performance.
Three types of capacitive fluidic sensors were demonstrated in several microfluidic applications. These include sensors for fluid pressure, flow rate, volume, and composition measurement. The sensors showed great promise for microfluidic applications because of their high sensitivity and easy integration capabilities. The integration of these sensors with abovementioned devices was achieved.
A novel electrochemical pumping system for on-chip LC gradient generation was demonstrated. This pump was able to deliver significant flow rates under high back pressures that are sufficient for many LC applications. On-chip gradient formation with integrated electrospray ionization was demonstrated.
Finally, a complete LC-ESI system was integrated in a chip format. Typical nano-LC reversed-phase gradient elution was demonstrated using on-chip electrolysis pump. Separated analytes from on-chip column were then sprayed into MS for analysis through an integrated ESI-nozzle. Separation results are comparable to those of commercial system. Peptide identification performance using the LC-ESI chip with MS was also very close to those achieved by the commercial system.</p
LC compensators for power factor correction of nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEA method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance of the obtained compensator is discussed by means of numerical examples
LC compensators based on transmission loss minimization for nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThis paper presents a method employing the penalty function search algorithm to determine the LC compensator value for the optimal power factor correction in nonsinusoidal systems. The objective of the proposed method is to minimize the transmission loss while the power factor and efficiency are taken as constraints and utilized in order to solve the multiobjective optimization problem by transforming it into a single objective one. Examples show that the load nonlinearity can have a significant impact on optimal compensator sizes
LC-MS/MS data for Zhang et al. NCB paper
No full textData deposited here include different type of RNA modifications examined by LC-MS/MS (liquid chromatography–tandem mass spectrometry). Different types of RNA modifications in sperm RNA fractions (15-25nt, 30-40nt, 40-100nt and >100 nt) extracted from F0 Dnmt2+/+ and Dnmt2-/- male mice under ND (normal diet) and HFD (High-fat diet) are processed for LC-MS/MS analysis
Flow chart of ICPL-peptide labeling- LC-MALDI and ICPL-protein labeling-LC-MALDI.
No full textFlow chart of ICPL-peptide labeling- LC-MALDI and ICPL-protein labeling-LC-MALDI.</p
The affinity of Si-N and Si-C bonding in amorphous silicon carbon nitride (a-SiCN) thin film
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