Михаил Царёв
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| | puma suede (7th Apr 20 at 8:46am UTC) | | Certified by the supplier as United States Pharmacopeia puma shoes (USP) Class VI-compliant, this PUMA resin has been tested thoroughly for its chemical inertness, working temperature, biocompatibility, and sterilizability all qualities necessary for manufacturing medical diagnostic devices.In this article, we focus on the back-end steps demolding, bonding, and interconnecting to external fluidic delivery of producing a PUMA chip. During demolding, high-aspect-ratio microstructures are prone to shear-induced damage.
Polydimethylsiloxane (PDMS) molds were prepared according to procedures described previously 18 from a molding master that was prepared by deep-reactive ion etching of silicon wafer and subsequently silanized with PUMA resin , CT) was dispensed to 3-mm thickness onto the PDMS mold, then covered with a sheet of fenty puma cellophane tacked to a clear polypropylene backing (8-mil thick) to prevent oxygen inhibition of the cross-linking reaction ( Fig. 1A ).
PUMA resin; 3 : PTFE posts; 4 : polypropylene sheet; 5 : cellophane (or Aclar). ( B ) rihanna puma Two methods of interfacing PUMA chip with external tubing: 1 : PUMA chip; 2 : barb elbow connector; 3 : polyurethane tubing; 4 : additional resin to seal leak (Dymax 186M); 5 : PTFE tubing; 6 : polyolefin heat-shrink; 7 : retaining ring.Fig. 1B shows two examples of interfacing a PUMA chip for external fluidic delivery. The left side of Fig. 1B illustrates the use of a barbed elbow connector.
The right side of Fig. 1B illustrates interfacing a 1/16-in puma suede OD (or of equivalent dimensions as PE100 tubing from Becton Dickinson) PTFE tubing with a PUMA chip. We found that conventional polyethylene (PE) tubing ( e.g. PE100), which is commonly used to interface with PDMS-based microfluidic devices, did not work well with PUMA chips, because (1) polyethylene surfaces are resistant to adhesive bonding, and (2) highly elastic tubings collapse easily when pulled in the longitudinal direction.
PDMS cannot be used as the material of fabrication because of low shear modulus; 6 the features would simply lean and topple over under gravity.Fig. 2 shows an example of features that can be fabricated in PUMA but not PDMS. Fig. 2A shows a scanning electron microscopy (SEM) image of a replica in PUMA resin; this test pattern for replication consists of densely spaced vertical columns alternating with solid walls. The feature puma sneakers height was ~40 ¼m and the aspect ratio of the vertical columns was ~3.5.
After UV curing, the PUMA-PDMS assembly was placed on the base suction cup and the vacuum pump was turned on. The base suction cup held the PDMS mold in place while the upper suction cup was slowly brought down to contact the transparent polypropylene cover on top of the cured resin. The touch-down speed should be sufficiently slow such that minimal downward force was exerted on the resin. Once the vacuum gauge on the pump dropped  from atmospheric pressure to the ultimate pressure of the pump. | |
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