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Minneapolis, MN, United States

Nowak J.D.,Hysitron Incorporated | Beaber A.R.,University of Minnesota | Ugurlu O.,University of Minnesota | Girshick S.L.,University of Minnesota | Gerberich W.W.,University of Minnesota
Scripta Materialia | Year: 2010

We use the ex situ and in situ deformation of silicon nano-spheres to investigate the mechanism(s) responsible for hardening, which consequently affects strength. With spheres in the 40-400 nm range, an inverse strength dependence was found. Applicability of linear, forest and/or exhaustion hardening are explored with the hypothesis that all three are of the same class limited by dislocation nucleation. © 2010 Acta Materialia Inc. Source


Patent
Hysitron Incorporated | Date: 2012-11-26

A microelectromechanical transducer and test system is disclosed. One embodiment includes a body, a probe moveable relative to the body, and a micromachined comb drive. The micromachined comb drive includes a plurality of sensing capacitors forming a differential capacitive displacement sensor, each sensing capacitor comprising a plurality of comb capacitors and each configured to provide capacitance levels which, together, are representative of a position of the probe.


Patent
Hysitron Incorporated | Date: 2012-11-28

A system and method of measuring an interaction force is disclosed. One embodiment includes providing a method of measuring an interaction force including providing a microelectromechanical transducer. The transducer includes a body, a probe moveable relative to the body, and a micromachined comb drive. The micromachined comb drive includes a differential capacitive displacement sensor to provide a sensor output signal representative of an interaction force on the probe. The probe is moved relative to a sample surface. An interaction force is determined between the probe and the sample surface using the sensor output, as the probe is moved relative to the sample surface.


Patent
Hysitron Incorporated | Date: 2011-05-02

A microelectromechanical (MEMS) nanoindenter transducer including a body, a probe coupled to and moveable relative to the body, the probe holding a removeable indenter tip, a first micromachined comb drive and a second micromachined comb drive. The first micromachined comb drive includes an actuator comprising a plurality of electrostatic capacitive actuators configured to drive the probe along a first axis, including in an indentation direction, in response to an applied bias voltage, and a displacement sensor comprising a plurality of differential capacitive sensors having capacitance levels which together are representative of a position of the probe relative to the first axis. The second micromachined comb drive includes an actuator comprising a plurality of electrostatic capacitive actuators configured to drive the probe along a second axis, which is perpendicular to the first axis, in response to an applied bias voltage, and a displacement sensor comprising a plurality of differential capacitive sensors having capacitance levels which together are representative of a position of the probe relative to the second axis. Each of the electrostatic capacitive actuators and the differential capacitive sensors comprises an electrode comb pair, each electrode comb pair including a fixed electrode comb coupled to the body and a moveable electrode comb coupled to the probe.


An actuatable capacitive transducer including a transducer body, a first capacitor including a displaceable electrode and electrically configured as an electrostatic actuator, and a second capacitor including a displaceable electrode and electrically configured as a capacitive displacement sensor, wherein the second capacitor comprises a multi-plate capacitor. The actuatable capacitive transducer further includes a coupling shaft configured to mechanically couple the displaceable electrode of the first capacitor to the displaceable electrode of the second capacitor to form a displaceable electrode unit which is displaceable relative to the transducer body, and an electrically-conductive indenter mechanically coupled to the coupling shaft so as to be displaceable in unison with the displaceable electrode unit.

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