Thomas Kenny
Richard W. Weiland Professor
Mechanical Engineering
Bio
Kenny's group is researching fundamental issues and applications of micromechanical structures. These devices are usually fabricated from silicon wafers using integrated circuit fabrication tools. Using these techniques, the group builds sensitive accelerometers, infrared detectors, and force-sensing cantilevers. This research has many applications, including integrated packaging, inertial navigation, fundamental force measurements, experiments on bio-molecules, device cooling, bio-analytical instruments, and small robots. Because this research field is multidisciplinary in nature, work in this group is characterized by strong collaborations with other departments, as well as with local industry.
Honors & Awards
-
General Chair, Transducers 2015 (2015)
-
Technical Achievement Award, IEEE (2011)
-
Program Manager, DARPA Microsystems Technology Office (2006-2010)
-
Captain, Ultimate Frisbee Coed World Champions (RFBF) (1999)
-
Captain, Ultimate Frisbee Coed National Champions (RFBF) (1998)
-
Terman Fellowship, Stanford University (1995-1998)
-
Robert Bosch Faculty Scholar, Robert Bosch Foundation (1995-1999)
-
CAREER Award, NSF (1995-1999)
Boards, Advisory Committees, Professional Organizations
-
Board of Directors, SiTime Corporation (2004 - Present)
Professional Education
-
PhD, UC Berkeley, Physics (1989)
Patents
-
Daniel J. Lenehan, Kenneth Goodson, Thomas W. Kenny, Mark Munch, Saroj Sahu. "United States Patent 8,602,292 Pump and Fan Control Concepts in a Cooling System", Cooligy, Inc, Dec 10, 2013
-
Thomas Kenny, Mark Munch, Peng Zhou, James Gill Shook, Kenneth Goodson, Dave Corbin, Mark McMaster, James Lovette. "United States Patent US 8,464,781 Cooling Systems Incorporating Heat Exchangers and Thermoelectric Layers", Cooligy, Inc, Jul 18, 2013
-
Robert J. Full, Ronald S. Fearing, Thomas W. Kenny, Kellar Autumn. "United States Patent US 6,737,160 Adhesive Microstructure and Method of Forming Same", The Regents Of The University Of California, May 18, 0004
2014-15 Courses
- Dim Sum of Mechanical Engineering
ME 201 (Aut) - Introduction to Mechatronics
EE 118, ME 210 (Win) - Introduction to Sensors
ME 220 (Spr) - Solid State Physics for Mechanical Engineering Experiments
ME 414 (Sum) -
Independent Studies (13)
- Directed Research and Writing in Aero/Astro
AA 190 (Aut, Win, Spr, Sum) - Directed Studies in Applied Physics
APPPHYS 290 (Aut, Win, Spr, Sum) - Engineering Problems
ME 391 (Aut, Win, Spr, Sum) - Engineering Problems and Experimental Investigation
ME 191 (Aut, Win, Spr, Sum) - Experimental Investigation of Engineering Problems
ME 392 (Aut, Win, Spr, Sum) - Honors Research
ME 191H (Aut, Win, Spr, Sum) - Independent Study in Aero/Astro
AA 199 (Aut, Win, Spr, Sum) - Ph.D. Teaching Experience
ME 491 (Aut, Win, Spr, Sum) - Practical Training
AA 291 (Sum) - Practical Training
APPPHYS 291 (Sum) - Practical Training
ME 299A (Aut, Win, Spr, Sum) - Practical Training
ME 299B (Aut, Win, Spr, Sum) - Problems in Aero/Astro
AA 290 (Aut, Win, Spr, Sum)
- Directed Research and Writing in Aero/Astro
-
Prior Year Courses
2013-14 Courses
- Dim Sum of Mechanical Engineering
ME 201 (Aut) - Introduction to Mechatronics
ME 210 (Win) - Introduction to Sensors
ME 220 (Spr)
2012-13 Courses
- Dim Sum of Mechanical Engineering
ME 201 (Aut) - Introduction to Mechatronics
ME 210 (Win) - Introduction to Sensors
ME 220 (Spr) - Solid State Physics for Mechanical Engineering Experiments
ME 414 (Sum)
2011-12 Courses
- Dim Sum of Mechanical Engineering
ME 201 (Aut) - Introduction to Mechatronics
ME 210 (Win) - Introduction to Sensors
ME 220 (Spr)
- Dim Sum of Mechanical Engineering
Journal Articles
-
Stability of Silicon Microelectromechanical Systems Resonant Thermometers
IEEE SENSORS JOURNAL
2013; 13 (3)
View details for DOI 10.1109/JSEN.2012.2227708
View details for Web of Science ID 000314690100011
-
Topology Optimization of Stressed Capacitive RF MEMS Switches
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2013; 22 (1): 206-215
View details for DOI 10.1109/JMEMS.2012.2224640
View details for Web of Science ID 000314726900028
-
Bidirectionally tuning Kapitza conductance through the inclusion of substitutional impurities
JOURNAL OF APPLIED PHYSICS
2012; 112 (7)
View details for DOI 10.1063/1.4757941
View details for Web of Science ID 000310489400041
-
Phase and thickness dependent modulus of Ge2Sb2Te5 films down to 25 nm thickness
APPLIED PHYSICS LETTERS
2012; 100 (16)
View details for DOI 10.1063/1.3699227
View details for Web of Science ID 000303128500018
-
Electrical and Thermal Conduction in Atomic Layer Deposition Nanobridges Down to 7 nm Thickness
NANO LETTERS
2012; 12 (2): 683-686
Abstract
While the literature is rich with data for the electrical behavior of nanotransistors based on semiconductor nanowires and carbon nanotubes, few data are available for ultrascaled metal interconnects that will be demanded by these devices. Atomic layer deposition (ALD), which uses a sequence of self-limiting surface reactions to achieve high-quality nanolayers, provides an unique opportunity to study the limits of electrical and thermal conduction in metal interconnects. This work measures and interprets the electrical and thermal conductivities of free-standing platinum films of thickness 7.3, 9.8, and 12.1 nm in the temperature range from 50 to 320 K. Conductivity data for the 7.3 nm bridge are reduced by 77.8% (electrical) and 66.3% (thermal) compared to bulk values due to electron scattering at material and grain boundaries. The measurement results indicate that the contribution of phonon conduction is significant in the total thermal conductivity of the ALD films.
View details for DOI 10.1021/nl203548w
View details for Web of Science ID 000299967800026
View details for PubMedID 22224582
-
Mechanical characterization of aligned multi-walled carbon nanotube films using microfabricated resonators
CARBON
2012; 50 (2): 347-355
View details for DOI 10.1016/j.carbon.2011.08.009
View details for Web of Science ID 000297397700001
-
Electrostatic Tuning to Achieve Higher Stability Microelectromechanical Composite Resonators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2011; 20 (6): 1355-1365
View details for DOI 10.1109/JMEMS.2011.2168083
View details for Web of Science ID 000297589200016
-
Stable Operation of MEMS Oscillators Far Above the Critical Vibration Amplitude in the Nonlinear Regime
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2011; 20 (6): 1228-1230
View details for DOI 10.1109/JMEMS.2011.2170821
View details for Web of Science ID 000297589200002
-
Influence of the temperature dependent nonlinearities on the performance of micromechanical resonators
APPLIED PHYSICS LETTERS
2011; 99 (19)
View details for DOI 10.1063/1.3660235
View details for Web of Science ID 000297030200082
-
Orientation angle and the adhesion of single gecko setae
JOURNAL OF THE ROYAL SOCIETY INTERFACE
2011; 8 (60): 926-933
Abstract
We investigated the effects of orientation angle on the adhesion of single gecko setae using dual-axis microelectromechanical systems force sensors to simultaneously detect normal and shear force components. Adhesion was highly sensitive to the pitch angle between the substrate and the seta's stalk. Maximum lateral adhesive force was observed with the stalk parallel to the substrate, and adhesion decreased smoothly with increasing pitch. The roll orientation angle only needed to be roughly correct with the spatular tuft of the seta oriented grossly towards the substrate for high adhesion. Also, detailed measurements were made to control for the effect of normal preload forces. Higher normal preload forces caused modest enhancement of the observed lateral adhesive force, provided that adequate contact was made between the seta and the substrate. These results should be useful in the design and manufacture of gecko-inspired synthetic adhesives with anisotropic properties, an area of substantial recent research efforts.
View details for DOI 10.1098/rsif.2010.0720
View details for Web of Science ID 000290898500002
View details for PubMedID 21288955
-
AC Polarization for Charge-Drift Elimination in Resonant Electrostatic MEMS and Oscillators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2011; 20 (2): 355-364
View details for DOI 10.1109/JMEMS.2010.2100027
View details for Web of Science ID 000289205400002
-
Wafer-Level Epitaxial Silicon Packaging for Out-of-Plane RF MEMS Resonators with Integrated Actuation Electrodes
IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY
2011; 1 (3): 310-317
View details for DOI 10.1109/TCPMT.2010.2100711
View details for Web of Science ID 000292780700004
-
3-D visualization of flow in microscale jet impingement systems
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
2011; 50 (3): 325-331
View details for DOI 10.1016/j.ijthermalsci.2010.08.005
View details for Web of Science ID 000287285700012
-
Active Electrostatic Compensation of Micromechanical Resonators Under Random Vibrations
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2010; 19 (5): 1270-1272
View details for DOI 10.1109/JMEMS.2010.2067444
View details for Web of Science ID 000283369500028
-
Effect of fibril shape on adhesive properties
APPLIED PHYSICS LETTERS
2010; 97 (5)
View details for DOI 10.1063/1.3464553
View details for Web of Science ID 000281059500064
-
What is the Young's Modulus of Silicon?
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2010; 19 (2): 229-238
View details for DOI 10.1109/JMEMS.2009.2039697
View details for Web of Science ID 000276257700001
-
Characterization of Encapsulated Micromechanical Resonators Sealed and Coated With Polycrystalline SiC
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2010; 19 (2): 357-366
View details for DOI 10.1109/JMEMS.2010.2040460
View details for Web of Science ID 000276257700014
-
A Method for Wafer-Scale Encapsulation of Large Lateral Deflection MEMS Devices
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2010; 19 (1): 28-37
View details for DOI 10.1109/JMEMS.2009.2035717
View details for Web of Science ID 000274213700003
-
Real-Time Temperature Compensation of MEMS Oscillators Using an Integrated Micro-Oven and a Phase-Locked Loop
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2010; 19 (1): 192-201
View details for DOI 10.1109/JMEMS.2009.2035932
View details for Web of Science ID 000274213700019
-
Model and Observations of Dielectric Charge in Thermally Oxidized Silicon Resonators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2010; 19 (1): 162-174
View details for DOI 10.1109/JMEMS.2009.2036274
View details for Web of Science ID 000274213700016
-
Development of wafer scale encapsulation process for large displacement piezoresistive MEMS devices
SENSORS AND ACTUATORS A-PHYSICAL
2009; 156 (2): 275-283
View details for DOI 10.1016/j.sna.2009.09.001
View details for Web of Science ID 000272563900001
-
Temperature-Insensitive Composite Micromechanical Resonators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2009; 18 (6): 1409-1419
View details for DOI 10.1109/JMEMS.2009.2030074
View details for Web of Science ID 000272318900027
-
Performance Evaluation and Equivalent Model of Silicon Interconnects for Fully-Encapsulated RF MEMS Devices
IEEE TRANSACTIONS ON ADVANCED PACKAGING
2009; 32 (2): 402-409
View details for DOI 10.1109/TADVP.2008.2005114
View details for Web of Science ID 000266778000018
-
Multimode thermoelastic dissipation
JOURNAL OF APPLIED PHYSICS
2009; 105 (4)
View details for DOI 10.1063/1.3072682
View details for Web of Science ID 000263803300018
-
Hermeticity and diffusion investigation in polysilicon film encapsulation for microelectromechanical systems
JOURNAL OF APPLIED PHYSICS
2009; 105 (1)
View details for DOI 10.1063/1.3054366
View details for Web of Science ID 000262534100047
-
Acceleration insensitive encapsulated silicon microresonator
APPLIED PHYSICS LETTERS
2008; 93 (23)
View details for DOI 10.1063/1.3036536
View details for Web of Science ID 000261699700087
-
Temperature dependence of quality factor in MEMS resonators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2008; 17 (3): 755-766
View details for DOI 10.1109/JMEMS.2008.924253
View details for Web of Science ID 000256626300023
-
Mission results for Sapphire, a student-built satellite
ACTA ASTRONAUTICA
2008; 62 (8-9): 521-538
View details for DOI 10.1016/j.actaastro.2008.01.009
View details for Web of Science ID 000255445100008
-
A study of electrostatic force nonlinearities in resonant microstructures
APPLIED PHYSICS LETTERS
2008; 92 (10)
View details for DOI 10.1063/1.2834707
View details for Web of Science ID 000253989300168
-
Thermal isolation of encapsulated MEMS resonators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2008; 17 (1): 175-184
View details for DOI 10.1109/JMEMS.2007.904332
View details for Web of Science ID 000253259600020
-
Ultraminiature encapsulated accelerometers as a fully implantable sensor for implantable hearing aids
BIOMEDICAL MICRODEVICES
2007; 9 (6): 939-949
Abstract
Experiments were conducted to evaluate a silicon accelerometer as an implantable sound sensor for implantable hearing aids. The main motivation of this study is to find an alternative sound sensor that is implantable inside the body, yet does not suffer from the signal attenuation from the body. The merit of the accelerometer sensor as a sound sensor will be that it will utilize the natural mechanical conduction in the middle ear as a source of the vibration. With this kind of implantable sound sensor, a totally implantable hearing aid is feasible. A piezoresistive silicon accelerometer that is completely encapsulated with a thin silicon film and long flexible flex-circuit electrical cables were used for this study. The sensor is attached on the middle ear ossicles and measures the vibration transmitted from the tympanic membrane due to the sound in the ear canal. In this study, the sensor is fully characterized on a human cadaveric temporal bone preparation.
View details for DOI 10.1007/s10544-007-9072-4
View details for Web of Science ID 000250462200019
View details for PubMedID 17574533
-
Scaling of amplitude-frequency-dependence nonlinearities in electrostatically transduced microresonators
JOURNAL OF APPLIED PHYSICS
2007; 102 (7)
View details for DOI 10.1063/1.2785018
View details for Web of Science ID 000250147700148
-
High resolution microresonator-based digital temperature sensor
APPLIED PHYSICS LETTERS
2007; 91 (7)
View details for DOI 10.1063/1.2768629
View details for Web of Science ID 000248866600117
-
Using the temperature dependence of resonator quality factor as a thermometer
APPLIED PHYSICS LETTERS
2007; 91 (1)
View details for DOI 10.1063/1.2753758
View details for Web of Science ID 000247819700074
-
Temperature-compensated high-stability silicon resonators
APPLIED PHYSICS LETTERS
2007; 90 (24)
View details for DOI 10.1063/1.2748092
View details for Web of Science ID 000247305400116
-
A multiaxis force sensor for the study of insect biomechanics
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2007; 16 (3): 709-718
View details for DOI 10.1109/JMEMS.2007.893677
View details for Web of Science ID 000247219200025
-
Frequency stability of wafer-scale film encapsulated silicon based MEMS resonators
SENSORS AND ACTUATORS A-PHYSICAL
2007; 136 (1): 125-131
View details for DOI 10.1016/j.sna.2006.10.040
View details for Web of Science ID 000246463000014
-
Wafer-scale fabrication of infrared detectors based on tunneling displacement transducers
SENSORS AND ACTUATORS A-PHYSICAL
2007; 134 (2): 575-581
View details for DOI 10.1016/j.sna.2005.07.028
View details for Web of Science ID 000245319900038
-
Inhibition of metalloprotease botulinum serotype A from a pseudo-peptide binding mode to a small molecule that is active in primary neurons
JOURNAL OF BIOLOGICAL CHEMISTRY
2007; 282 (7): 5004-5014
Abstract
An efficient research strategy integrating empirically guided, structure-based modeling and chemoinformatics was used to discover potent small molecule inhibitors of the botulinum neurotoxin serotype A light chain. First, a modeled binding mode for inhibitor 2-mercapto-3-phenylpropionyl-RATKML (K(i) = 330 nM) was generated, and required the use of a molecular dynamic conformer of the enzyme displaying the reorientation of surface loops bordering the substrate binding cleft. These flexible loops are conformationally variable in x-ray crystal structures, and the model predicted that they were pivotal for providing complementary binding surfaces and solvent shielding for the pseudo-peptide. The docked conformation of 2-mercapto-3-phenylpropionyl-RATKML was then used to refine our pharmacophore for botulinum serotype A light chain inhibition. Data base search queries derived from the pharmacophore were employed to mine small molecule (non-peptidic) inhibitors from the National Cancer Institute's Open Repository. Four of the inhibitors possess K(i) values ranging from 3.0 to 10.0 microM. Of these, NSC 240898 is a promising lead for therapeutic development, as it readily enters neurons, exhibits no neuronal toxicity, and elicits dose-dependent protection of synaptosomal-associated protein (of 25 kDa) in a primary culture of embryonic chicken neurons. Isothermal titration calorimetry showed that the interaction between NSC 240898 and the botulinum A light chain is largely entropy-driven, and occurs with a 1:1 stoichiometry and a dissociation constant of 4.6 microM.
View details for DOI 10.1074/jbc.M608166200
View details for Web of Science ID 000244482000083
View details for PubMedID 17092934
-
Acceleration sensitivity in beam-type electrostatic microresonators
APPLIED PHYSICS LETTERS
2007; 90 (1)
View details for DOI 10.1063/1.2426884
View details for Web of Science ID 000243379900112
-
Long-term and accelerated life testing of a novel single-wafer vacuum encapsulation for MEMS resonators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2006; 15 (6): 1446-1456
View details for DOI 10.1109/JMEMS.2006.883586
View details for Web of Science ID 000242983300004
-
Engineering MEMS resonators with low thermoelastic damping
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2006; 15 (6): 1437-1445
View details for DOI 10.1109/JMEMS.2006.883573
View details for Web of Science ID 000242983300003
-
Optimal drive condition for nonlinearity reduction in electrostatic microresonators
APPLIED PHYSICS LETTERS
2006; 89 (21)
View details for DOI 10.1063/1.2388886
View details for Web of Science ID 000242220000087
-
Impact of geometry on thermoelastic dissipation in micromechanical resonant beams
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2006; 15 (4): 927-934
View details for DOI 10.1109/JMEMS.2006.879374
View details for Web of Science ID 000239712600023
-
A hybrid method for bubble geometry reconstruction in two-phase microchannels
EXPERIMENTS IN FLUIDS
2006; 40 (6): 847-858
View details for DOI 10.1007/s00348-006-0123-z
View details for Web of Science ID 000239549100003
-
Encapsulated submillimeter piezoresistive accelerometers
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2006; 15 (3): 507-514
View details for DOI 10.1109/JMEMS.2006.876648
View details for Web of Science ID 000238311000007
-
Two-phase microfluidics for semiconductor circuits and fuel cells
HEAT TRANSFER ENGINEERING
2006; 27 (4): 53-63
View details for DOI 10.1080/01457630500523816
View details for Web of Science ID 000236239500006
-
Phase change phenomena in silicon microchannels
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
2005; 48 (8): 1572-1582
View details for DOI 10.1016/j.ijheatmasstransfer.2004.09.048
View details for Web of Science ID 000228228400015
-
Micromachined jets for liquid impingement cooling of VLSI chips (vol 13, pg 833, 2004)
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2004; 13 (6): 1072-1072
View details for DOI 10.1109/JMEMS.2004.840851
View details for Web of Science ID 000225515100022
-
Micromachined jets for liquid impingement cooling of VLSI chips
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2004; 13 (5): 833-842
View details for DOI 10.1109/JMEMS.2004.835768
View details for Web of Science ID 000224413100014
-
Comparison of thermal and piezoresistive sensing approaches for atomic force microscopy topography measurements
APPLIED PHYSICS LETTERS
2004; 85 (11): 2086-2088
View details for DOI 10.1063/1.1787160
View details for Web of Science ID 000223923300073
-
Fatigue crack growth in micro-machined single-crystal silicon
JOURNAL OF MATERIALS RESEARCH
2004; 19 (9): 2635-2640
View details for DOI 10.1557/JMR.2004.0343
View details for Web of Science ID 000223689000017
-
Nucleation and growth of vapor bubbles in a heated silicon microchannel
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
2004; 126 (4): 497-497
View details for Web of Science ID 000223989100004
-
Measurement system for low force and small displacement contacts
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2004; 13 (2): 220-229
View details for Web of Science ID 000220759300008
-
High speed particles separation using ultrasound for microTAS and lab-on-a-chip application.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference
2004; 4: 2631-2634
Abstract
Engineers have long envisioned that a handheld portable blood diagnosis device would be able to give an accurate measurement of chemical content based on a very small sample in the shortest time possible. One of the immediate applications of such device is the point of care (POC) diagnosis system, whereby a single drop of human blood would determine his health status. However, a major technical challenge lies in the ability to separate different particles, which in the case of human blood, is to separate red and white blood cells and plasma in a quick, cheap, reliable device with low power consumption. In this paper, we present some preliminary results from our tests of ultrasound standing waves as a potential separation mechanism for blood cells. Also, we report on the study of the behavior of suspended particles of the size equivalent to a human cell under the influence of ultrasonic acoustic field, using micro particle image velocimetry (PIV) measurement technique. This provides the fundamental understanding and foundation of designing an integrated microchannel structure that can provide ultrasonic cell separation in the microscale regime. The study has shown promising results of successfully separating two different particles based on their sizes difference.
View details for PubMedID 17270815
-
Measurements of cooling by room-temperature thermionic emission across a nanometer gap
JOURNAL OF APPLIED PHYSICS
2003; 94 (7): 4690-4696
View details for DOI 10.1063/1.1606852
View details for Web of Science ID 000185420900071
-
Stress wave interference effects during fracture of silicon micromachined specimens
EXPERIMENTAL MECHANICS
2003; 43 (3): 317-322
View details for Web of Science ID 000185166800011
-
Single wafer encapsulation of MEMS devices
IEEE TRANSACTIONS ON ADVANCED PACKAGING
2003; 26 (3): 227-232
View details for DOI 10.1109/TADVP.2003.818062
View details for Web of Science ID 000185862400003
-
Design of piezoresistive MEMS-based accelerometer for integration with wireless sensing unit for structural monitoring
JOURNAL OF AEROSPACE ENGINEERING
2003; 16 (3): 108-114
View details for DOI 10.1016/(ASCE)0893-1321(2003)16:3(108)
View details for Web of Science ID 000183657900002
-
Design of large deflection electrostatic actuators
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2003; 12 (3): 335-343
View details for DOI 10.1109/JMEMS.2003.811750
View details for Web of Science ID 000183356300013
-
Piezoresistive cantilevers and measurement system for characterizing low force electrical contacts
SENSORS AND ACTUATORS A-PHYSICAL
2003; 104 (1): 68-77
View details for DOI 10.1016/S0924-4247(02)00485-5
View details for Web of Science ID 000181236100011
-
Embedment of structural monitoring algorithms in a wireless sensing unit
STRUCTURAL ENGINEERING AND MECHANICS
2003; 15 (3): 285-297
View details for Web of Science ID 000181569500002
-
On-chip coupling of isoelectric focusing and free solution electrophoresis for multidimensional separations
ANALYTICAL CHEMISTRY
2003; 75 (5): 1180-1187
Abstract
We have developed an acrylic microfluidic device that sequentially couples liquid-phase isoelectric focusing (IEF) and free solution capillary electrophoresis (CE). Rapid separation (<1 min) and preconcentration (73x) of species were achieved in the initial IEF dimension. Using full-field fluorescence imaging, we observed nondispersive mobilization velocities on the order of 20 microm/s during characterization of the IEF step. This transport behavior allowed controlled electrokinetic mobilization of focused sample bands to a channel junction, where voltage switching was used to repeatedly inject effluent from the IEF dimension into an ampholyte-based CE separation. This second dimension was capable of analyzing all fluid volumes of interest from the IEF dimension, as IEF was 'parked' during each CE analysis and refocused prior to additional CE analyses. Investigation of each dimension of the integrated system showed time-dependent species displacement and band-broadening behavior consistent with IEF and CE, respectively. The peak capacity of the 2D system was approximately 1300. A comprehensive 2D analysis of a fluid volume spanning 15% of the total IEF channel length was completed in less than 5 min.
View details for DOI 10.1021/ac026239a
View details for Web of Science ID 000181259300027
View details for PubMedID 12641239
-
Design of atomic force microscope cantilevers for combined thermomechanical writing and thermal reading in array operation
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2002; 11 (6): 765-774
View details for DOI 10.1109/JMEMS.2002.803283
View details for Web of Science ID 000179740900017
-
Process compatible polysilicon-based electrical through-wafer interconnects in silicon substrates
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2002; 11 (6): 631-640
View details for DOI 10.1109/JMEMS.2002.805206
View details for Web of Science ID 000179740900002
-
Vacuum thermionic refrigeration with a semiconductor heterojunction structure
APPLIED PHYSICS LETTERS
2002; 81 (22): 4242-4244
View details for DOI 10.1063/1.1523653
View details for Web of Science ID 000179340800048
-
Evidence for van der Waals adhesion in gecko setae
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2002; 99 (19): 12252-12256
Abstract
Geckos have evolved one of the most versatile and effective adhesives known. The mechanism of dry adhesion in the millions of setae on the toes of geckos has been the focus of scientific study for over a century. We provide the first direct experimental evidence for dry adhesion of gecko setae by van der Waals forces, and reject the use of mechanisms relying on high surface polarity, including capillary adhesion. The toes of live Tokay geckos were highly hydrophobic, and adhered equally well to strongly hydrophobic and strongly hydrophilic, polarizable surfaces. Adhesion of a single isolated gecko seta was equally effective on the hydrophobic and hydrophilic surfaces of a microelectro-mechanical systems force sensor. A van der Waals mechanism implies that the remarkable adhesive properties of gecko setae are merely a result of the size and shape of the tips, and are not strongly affected by surface chemistry. Theory predicts greater adhesive forces simply from subdividing setae to increase surface density, and suggests a possible design principle underlying the repeated, convergent evolution of dry adhesive microstructures in gecko, anoles, skinks, and insects. Estimates using a standard adhesion model and our measured forces come remarkably close to predicting the tip size of Tokay gecko seta. We verified the dependence on size and not surface type by using physical models of setal tips nanofabricated from two different materials. Both artificial setal tips stuck as predicted and provide a path to manufacturing the first dry, adhesive microstructures.
View details for DOI 10.1073/pnas.192252799
View details for Web of Science ID 000178187000048
View details for PubMedID 12198184
-
Subcritical crack growth in single-crystal silicon using micromachined specimens
JOURNAL OF MATERIALS RESEARCH
2002; 17 (3): 683-692
View details for Web of Science ID 000174300000027
-
Measurements and modeling of two-phase flow in microchannels with nearly constant heat flux boundary conditions
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2002; 11 (1): 12-19
View details for Web of Science ID 000173751000002
-
Characterization of a two-dimensional cantilever array with through-wafer electrical interconnects
APPLIED PHYSICS LETTERS
2002; 80 (4): 664-666
View details for Web of Science ID 000173508900044
-
Electron spin relaxation near a micron-size ferromagnet
PHYSICAL REVIEW LETTERS
2001; 87 (27)
Abstract
Magnetic resonance force microscopy was used to study the behavior of small ensembles of unpaired electron spins in silica near a micrometer-size ferromagnetic tip. Using a cantilever-driven spin manipulation protocol and a magnetic field gradient greater than 10(5) T/m, signals from as few as 100 net spins within a 20 nm thick resonant slice could be studied. A sixfold increase in the spin-lattice relaxation rate was found within 800 nm of the ferromagnet, while no effect due to silica surface proximity was detected. The results are interpreted in terms of Larmor-frequency magnetic field fluctuations emanating from the ferromagnet.
View details for DOI 10.1103/PhysRevLett.87.277602
View details for Web of Science ID 000173040800056
View details for PubMedID 11800915
-
A high-stiffness axial resonant probe for atomic force microscopy
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2001; 10 (3): 434-441
View details for Web of Science ID 000170875900013
-
A high-precision, wide-bandwidth micromachined tunneling accelerometer
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2001; 10 (3): 425-433
View details for Web of Science ID 000170875900012
-
Noncontact friction and force fluctuations between closely spaced bodies
PHYSICAL REVIEW LETTERS
2001; 87 (9)
Abstract
Noncontact friction between a Au(111) surface and an ultrasensitive gold-coated cantilever was measured as a function of tip-sample spacing, temperature, and bias voltage using observations of cantilever damping and Brownian motion. The importance of the inhomogeneous contact potential is discussed and comparison is made to measurements over dielectric surfaces. Using the fluctuation-dissipation theorem, the force fluctuations are interpreted in terms of near-surface fluctuating electric fields interacting with static surface charge.
View details for DOI 10.1103/PhysRevLett.87.096801
View details for Web of Science ID 000170698000030
View details for PubMedID 11531586
-
Nanometer-Scale Force Sensing with MEMS Devices
IEEE SENSORS JOURNAL
2001; 1 (2): 148-157
View details for DOI 10.1109/JSEN.2001.936932
View details for Web of Science ID 000208325600006
-
Refrigeration by combined tunneling and thermionic emission in vacuum: Use of nanometer scale design
APPLIED PHYSICS LETTERS
2001; 78 (17): 2572-2574
View details for Web of Science ID 000168304600053
-
Magnetic dissipation and fluctuations in individual nanomagnets measured by ultrasensitive cantilever magnetometry
PHYSICAL REVIEW LETTERS
2001; 86 (13): 2874-2877
Abstract
Cantilever magnetometry with moment resolution better than 10(4)micro(B) was used to study individual nanomagnets. By using the fluctuation-dissipation theorem to interpret measurements of field-induced cantilever damping, the low frequency spectral density of magnetic fluctuations could be determined with resolution better than 1micro(B) Hz-1/2. Cobalt nanowires exhibited significant magnetic dissipation and the associated magnetic fluctuations were found to have 1/f frequency dependence. In individual submicron rare-earth alloy magnets, the dissipation/fluctuation was very small and not distinguishable from that of a bare silicon cantilever.
View details for Web of Science ID 000167693000044
View details for PubMedID 11290061
-
Optimization of turn geometries for microchip electrophoresis
ANALYTICAL CHEMISTRY
2001; 73 (6): 1350-1360
View details for Web of Science ID 000167546400042
-
Adventures in attonewton force detection
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
2001; 72: S3-S10
View details for DOI 10.1007/s003390100729
View details for Web of Science ID 000205245800002
-
Atomic force microscope cantilevers for combined thermomechanical data writing and reading
APPLIED PHYSICS LETTERS
2001; 78 (9): 1300-1302
View details for Web of Science ID 000167151000044
-
Adhesive force of a single gecko foot-hair
NATURE
2000; 405 (6787): 681-685
Abstract
Geckos are exceptional in their ability to climb rapidly up smooth vertical surfaces. Microscopy has shown that a gecko's foot has nearly five hundred thousand keratinous hairs or setae. Each 30-130 microm long seta is only one-tenth the diameter of a human hair and contains hundreds of projections terminating in 0.2-0.5 microm spatula-shaped structures. After nearly a century of anatomical description, here we report the first direct measurements of single setal force by using a two-dimensional micro-electromechanical systems force sensor and a wire as a force gauge. Measurements revealed that a seta is ten times more effective at adhesion than predicted from maximal estimates on whole animals. Adhesive force values support the hypothesis that individual seta operate by van der Waals forces. The gecko's peculiar behaviour of toe uncurling and peeling led us to discover two aspects of setal function which increase their effectiveness. A unique macroscopic orientation and preloading of the seta increased attachment force 600-fold above that of frictional measurements of the material. Suitably orientated setae reduced the forces necessary to peel the toe by simply detaching above a critical angle with the substratum.
View details for Web of Science ID 000087465800046
View details for PubMedID 10864324
-
1/F noise considerations for the design and process optimization of piezoresistive cantilevers
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2000; 9 (2): 226-235
View details for Web of Science ID 000087842600008
-
Quality factors in micron- and submicron-thick cantilevers
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2000; 9 (1): 117-125
View details for Web of Science ID 000085857600017
-
Electroosmotic capillary flow with nonuniform zeta potential
ANALYTICAL CHEMISTRY
2000; 72 (5): 1053-1057
View details for Web of Science ID 000085605100043
-
Electroosmotic capillary flow with nonuniform zeta potential
Analytical chemistry
2000; 72 (5): 1053-7
Abstract
The present work is an analytical and experimental study of electroosmotic flow (EOF) in cylindrical capillaries with nonuniform wall surface charge (zeta-potential) distributions. In particular, this study investigates perturbations of electroosmotic flow in open capillaries that are due to induced pressure gradients resulting from axial variations in the wall zeta-potential. The experimental inquiry focuses on electroosmotic flow under a uniform applied field in capillaries with an EOF-suppressing polymer adsorbed onto various fractions of the total capillary length. This fractional EOF suppression was achieved by coupling capillaries with substantially different zeta-potentials. The resulting flow fields were imaged with a nonintrusive, caged-fluorescence imaging technique. Simple analytical models for the velocity field and rate of sample dispersion in capillaries with axial zeta-potential variations are presented. The resulting induced pressure gradients and the associated band-broadening effects are of particular importance to the performance of chemical and biochemical analysis systems such as capillary electrokinetic chromatography and capillary zone electrophoresis.
View details for PubMedID 10739211
-
Silicon dopant imaging by dissipation force microscopy
APPLIED PHYSICS LETTERS
1999; 75 (18): 2785-2787
View details for Web of Science ID 000083295500027
-
An integrated controller for tunnel sensors
IEEE JOURNAL OF SOLID-STATE CIRCUITS
1999; 34 (8): 1099-1107
View details for Web of Science ID 000081755500009
-
High-sensitivity piezoresistive cantilevers under 1000 angstrom thick
APPLIED PHYSICS LETTERS
1999; 75 (2): 289-291
View details for Web of Science ID 000081265200047
-
Intrinsic-carrier thermal runaway in silicon microcantilevers
MICROSCALE THERMOPHYSICAL ENGINEERING
1999; 3 (3): 217-228
View details for Web of Science ID 000082536200006
-
Ultrahigh-density atomic force microscopy data storage with erase capability
APPLIED PHYSICS LETTERS
1999; 74 (9): 1329-1331
View details for Web of Science ID 000079010000047
-
Technique for measurement of the noise of a sensor in the presence of large background signals
REVIEW OF SCIENTIFIC INSTRUMENTS
1998; 69 (7): 2767-2772
View details for Web of Science ID 000075279200030
-
Characterization of a high-sensitivity micromachined tunneling accelerometer with micro-g resolution
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
1998; 7 (2): 235-244
View details for Web of Science ID 000073957900012
-
Independent detection of vertical and lateral forces with a sidewall-implanted dual-axis piezoresistive cantilever
APPLIED PHYSICS LETTERS
1998; 72 (11): 1388-1390
View details for Web of Science ID 000072566000043
-
Low-stiffness silicon cantilevers with integrated heaters and piezoresistive sensors for high-density AFM thermomechanical data storage
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
1998; 7 (1): 69-78
View details for Web of Science ID 000073005900009
-
Attonewton force detection using ultrathin silicon cantilevers
APPLIED PHYSICS LETTERS
1997; 71 (2): 288-290
View details for Web of Science ID A1997XK16000047
-
Fabrication of collimating grids for an x-ray solar telescope using LIGA methods
MICROSYSTEM TECHNOLOGIES
1997; 3 (3): 91-96
View details for Web of Science ID A1997YD29700001
-
Low-stiffness silicon cantilevers for thermal writing and piezoresistive readback with the atomic force microscope
APPLIED PHYSICS LETTERS
1996; 69 (18): 2767-2769
View details for Web of Science ID A1996VP26500049
-
Micromachined infrared sensors using tunneling displacement transducers
REVIEW OF SCIENTIFIC INSTRUMENTS
1996; 67 (1): 112-128
View details for Web of Science ID A1996TQ62300016
-
WIDE-BANDWIDTH ELECTROMECHANICAL ACTUATORS FOR TUNNELING DISPLACEMENT TRANSDUCERS
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
1994; 3 (3): 97-104
View details for Web of Science ID A1994RM17600002
Conference Proceedings
-
Development and characterization of a TES optical imaging array for astrophysics applications
ELSEVIER SCIENCE BV. 2004: 533-536
View details for DOI 10.1016/j.nima.2003.11.307
View details for Web of Science ID 000220606900143
-
Closed-loop electroosmotic microchannel cooling system for VLSI circuits
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2002: 347-355
View details for DOI 10.1109/TCAPT.2002.800599
View details for Web of Science ID 000180333200003
-
E-cadherin extra-cellular domain interaction examined by atomic force microscopy
CELL PRESS. 2002: 55A-55A
View details for Web of Science ID 000173252700273
-
Integration of through-wafer interconnects with a two-dimensional cantilever array
ELSEVIER SCIENCE SA. 2000: 118-123
View details for Web of Science ID 000087144800019
-
Fracture toughness and crack growth phenomena of plasma-etched single crystal silicon
ELSEVIER SCIENCE SA. 2000: 194-199
View details for Web of Science ID 000087144800031
-
Rapid biochemical detection and differentiation with magnetic force microscope cantilever arrays
ELSEVIER SCIENCE SA. 2000: 256-262
View details for Web of Science ID 000087144800041
-
Packaging a piezoresistive pressure sensor to measure low absolute pressures over a wide sub-zero temperature range
ELSEVIER SCIENCE SA. 2000: 142-149
View details for Web of Science ID 000087144800023
-
Torsional force probes optimized for higher order mode suppression
I E E E. 1997: 141-144
View details for Web of Science ID A1997BJ35B00032
-
A miniature, high-sensitivity, electron tunneling accelerometer
ELSEVIER SCIENCE SA. 1996: 227-231
View details for Web of Science ID A1996UV64900002
-
SENSORS BASED ON TUNNELING DISPLACEMENT TRANSDUCERS - DESIGN, APPLICATIONS, AND LIMITATIONS
AMER CHEMICAL SOC. 1995: 50-COLL
View details for Web of Science ID A1995QP23201561