3,415 research outputs found
Design, fabrication, and testing of micromachined silicone rubbermembrane valves
Technologies for fabricating silicone rubber membranes and integrating them with other processes on silicon wafers have been developed. Silicone rubber has been found to have exceptional mechanical properties including low modulus, high elongation, and good sealing. Thermopneumatically actuated, normally open, silicone rubber membrane valves with optimized components have been designed, fabricated, and tested. Suspended silicon nitride membrane heaters have been developed for low-power thermopneumatic actuation. Composite silicone rubber on Parylene valve membranes have been shown to have low permeability and modulus. Also, novel valve seats were designed to improve sealing in the presence of particles. The valves have been extensively characterized with respect to power consumption versus flow rate and transient response. Low power consumption, high flow rate, and high pressure have been demonstrated. For example, less than 40 mW is required to switch a 1-slpm nitrogen flow at 33 psi. Water requires dose to 100 mW due to the cooling effect of the liquid
Constraints on anomalous quartic gauge couplings via production at the LHC
The vector boson scattering at the Large Hadron Collider (LHC) is sensitive
to anomalous quartic gauge couplings (aQGCs). In this paper, we investigate the
aQGC contribution to production at the LHC with
TeV in the context of an effective field theory (EFT). The unitarity bound is
applied as a cut on the energy scale of this production process, which is found
to have significant suppressive effects on the signals. To enhance the
statistical significance, we analyse the kinematic and polarization features of
the aQGC signals in detail. We find that the polarization effects induced by
the aQGCs are unique and can discriminate the signals from the SM backgrounds
well. With the proposed event selection strategy, we obtain the constraints on
the coefficients of dimension-8 operators with current luminosity. The results
indicate that the process is powerful for searching for
the and operators.Comment: 29 pages, 11 figures, 7 tables, to be published in Chinese Physics
The marching velocity of the capillary meniscus in a microchannel
In this paper we describe an experimental method and an analytical model for characterizing the surface energy inside a microchannel of micrometer size by measuring the marching velocity or position of a capillary meniscus. This method is based on the fact that the force summation of the meniscus surface tension and the filling reservoir gravitation might produce a pressure to pull liquid into the channel, and the marching velocity or the instantaneous position of the meniscus is related to the surface energy. Both parylene and silicon-nitride microchannels with different surface conditions were fabricated to perform the fill-in experiments subject to different liquids. It is shown that our model agrees well with the experimental data and is a valid method
Dynamic simulation of a peristaltic micropump considering coupled fluid flow and structural motion
This paper presents lumped-parameter simulation of dynamic characteristics of peristaltic micropumps. The pump consists of three pumping cells connected in series, each of which is equipped with a compliant diaphragm that is electrostatically actuated in a peristaltic sequence to mobilize the fluid. Diaphragm motion in each pumping cell is first represented by an effective spring subjected to hydrodynamic and electrostatic forces. These cell representations are then used to construct a system-level model for the entire pump, which accounts for both cell- and pump-level interactions of fluid flow and diaphragm vibration. As the model is based on first principles, it can be evaluated directly from the device's geometry, material properties and operating parameters without using any experimentally identified parameters. Applied to an existing pump, the model correctly predicts trends observed in experiments. The model is then used to perform a systematic analysis of the impact of geometry, materials and pump loading on device performance, demonstrating its utility as an efficient tool for peristaltic micropump design
Associated production of the heavy charged gauge boson and a top quark at LHC
In the context of topflavor seesaw model, we study the production of the
heavy charged gauge boson associated with a top quark at the LHC.
Focusing on the searching channel , we carry out a full simulation of the signal and the
relevant standard model backgrounds. The kinematical distributions of final
states are presented. It is found that the backgrounds can be significantly
suppressed by sets of kinematic cuts, and the signal of the heavy charged boson
might be detected at the LHC with TeV. With a integrated
luminosity of \LL= 100 , a signal significance can be
achieved for TeV.Comment: 16 pages, 6 figure
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