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Direct measurement of the maximum tunnel rate in a radio frequency single electron transistor operated as a microwave mixer
By operating the radio frequency single electron transistor (rf-SET) as a
mixer we present measurements in which the RC roll-off of the tunnel junctions
is observed at high frequencies. Our technique makes use of the non-linear
rf-SET transconductance to mix high frequency gate signals and produce
difference-frequency components that fall within the bandwidth of the rf-SET.
At gate frequencies >15GHz the induced charge on the rf-SET island is altered
on time-scales faster than the inverse tunnel rate, preventing mixer operation.
We suggest the possibility of utilizing this technique to sense high frequency
signals beyond the usual rf-SET bandwidth.Comment: Submitted to Applied Physics Letters. Comments always very welcome,
email:[email protected] (New version contains extra data and new figs
Elastomer coated filler and composites thereof comprising at least 60% by weight of a hydrated filler and an elastomer containing an acid substituent
The impact resistance of flame retardant composites, especially thermoplastic molding: compounds containing over 60% hydrated mineral filler such as Al(OH)3 or Mg(OH)2 as improved by coating the filler with 1 to 20% of an elastomer. The composite will fail by crazing or shearing rather than by brittle fracture. A well bonded elastomeric interphase resulted by utilizing acidic substituted resins such as ethyl-hexyl acrylate-acrylic acid copolymers which bond to and are cross-linked by the basic filler particles. Further improvement in impact resistance was provided by incorporating 1 to 10% of a resin fiber reinforcement such as polyvinyl alcohol fibers that decompose to yield at least 30% water when heated to decomposition temperature
Fast Single-Charge Sensing with an rf Quantum Point Contact
We report high-bandwidth charge sensing measurements using a GaAs quantum
point contact embedded in a radio frequency impedance matching circuit
(rf-QPC). With the rf-QPC biased near pinch-off where it is most sensitive to
charge, we demonstrate a conductance sensitivity of 5x10^(-6) e^(2)/h Hz^(-1/2)
with a bandwidth of 8 MHz. Single-shot readout of a proximal few-electron
double quantum dot is investigated in a mode where the rf-QPC back-action is
rapidly switched.Comment: related papers available at http://marcuslab.harvard.ed
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