Non-Contact Mechanical Testing and Characterization of Micro-Scale Structures

2006 ◽  
Author(s):  
Jian Chen ◽  
Ganesh Subramanian ◽  
Justin Ricci ◽  
Liang Ban ◽  
Cetin Cetinkaya
Keyword(s):  
Plane Motion ◽  
Cantilever Beams ◽  
Micro Scale ◽  
New Class ◽  
Sensor Platform ◽  
Out Of Plane ◽  
Modes Of Vibration ◽  
Scale Structures ◽  
Micro Cantilever

A non-contact testing and characterization method based on air-coupled acoustic excitation and interferometric displacement measurements of micro-scale MEMS structures at room conditions is introduced. In demonstrating its potential uses in testing and characterization, the present non-contact approach is applied to (i) micro-cantilever beams and (ii) rotational disk oscillators. Air-coupled multi-mode excitation of micromechanical cantilever-type oscillators under a pulsed acoustic field generated by an air-coupled transducer is demonstrated and reported. Also, the testing and characterization of a micro-scale rotational disk oscillator developed for a new class of sensor platform is demonstrated. The main design objective of the rotational disk oscillator class is to overcome the out-of-plane motion related sensitivity limitations of the cantilever-based sensors at high frequency operations. The dynamics of the rotational disk oscillators is more complex than micro-cantilever beams due to its in-plane motion in addition to its various out-of-plane modes of vibration. The fabrication of a rotational disk oscillator requires a suspended disk whose underside is visibly inaccessible due to a narrow micro-gap. In addition to the dynamic characterization of the cantilever beams and rotational disk oscillators, the current investigation demonstrates that the presented approach can address unique structural concerns such as the verification of a gap separation of the rotational oscillator from the underlying silicon substrate. Utilizing the proposed technique, the resonant frequencies of the oscillator structures are obtained and its potential uses in the testing and characterization of micro-scale structures are discussed. The major specific advantages of the introduced approach include that (i) its noncontact nature can eliminate testing problems associated with stiction and adhesion, and (ii) it allows direct mechanical characterization and testing of components and sub-components of a micro-scale devices.

Development of Latching Type Large Vertical-Travel Microactuator

2005 ◽  
Author(s):  
Risaku Toda ◽  
Eui-Hyeok Yang
Keyword(s):  
Plane Motion ◽  
Proof Of Concept ◽  
Test Device ◽  
Comb Drive ◽  
Pzt Actuator ◽  
Comb Drives ◽  
Out Of Plane ◽  
Sequential Activation ◽  
Vertical Travel

This paper describes design, fabrication and preliminary characterization of a proof-of-concept vertical-travel microactuator, providing linear motion and high precision positioning in space. The microactuator is capable of providing latching function when it is un-powered to maintain its position. The microactuator consists of two opposing comb drive actuator dies, a slider and bulk PZT actuators sandwiched between the dies. The slider is inserted between clutches. Comb drives are connected to the clutches to engage/disengage clutching. Sequential activation of the comb drives (in-plane motion) and the PZT actuator (out-of-plane motion) provides cumulative linear travel of the slider. The novelty of the slider insertion approach include (1) post-fabrication engagement of comb teeth enabling thick wafer DRIE process for comb drive actuators and (2) stressed tethers enabling zero-power latching. A test device was fabricated and assembled. By applying 100V∼300V DC to the electrostatic comb drive, lateral actuation of clutches was observed. Vertical actuation by PZT was also confirmed using WYKO RST plus interferometer.

3D surface profilometry for both static and dynamic nanoscale full field characterization of AFM micro cantilever beams

2005 ◽  
Author(s):  
Liang-Chia Chen ◽  
Kuang-Chao Fan ◽  
Chi-Duen Lin ◽  
Calvin C. Chang ◽  
Ching-Fen Kao ◽  
...  
Keyword(s):  
Cantilever Beams ◽  
Full Field ◽  
Surface Profilometry ◽  
3D Surface ◽  
Micro Cantilever

Characterization of the Dynamical Response of a Micromachined G-Sensor to Mechanical Shock Loading

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Daniel Jordy ◽  
Mohammad I. Younis
Keyword(s):  
Element Model ◽  
Plane Motion ◽  
Squeeze Film ◽  
Dynamical Response ◽  
Mechanical Shock ◽  
Mems Devices ◽  
Squeeze Film Damping ◽  
Out Of Plane ◽  
Gap Width

Squeeze film damping has a significant effect on the dynamic response of microelectromechanical system (MEMS) devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering damping. By decreasing the size of the holes, damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, the performance of a G-sensor (threshold accelerometer) employed in an arming and fusing chip is investigated. The effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate are studied. A multiphysics finite-element model built using the software ANSYS is utilized for the fluidic and transient structural analysis. A squeeze film damping model, for both the air underneath the structure and the flow of the air through the perforations, is developed. Results are shown for various models of squeeze film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. It is found that the threshold of shock that causes the G-sensor to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability.

Targeting IDH Mutations in AML: Wielding the Double-edged Sword of Differentiation

2020 ◽  
Vol 20 (7) ◽  
pp. 490-500 ◽  
Author(s):  
Justin S. Becker ◽  
Amir T. Fathi
Keyword(s):  
Genome Structure ◽  
Cellular Metabolism ◽  
Standard Of Care ◽  
Competitive Inhibitor ◽  
Driver Mutations ◽  
New Class ◽  
Regulatory Enzymes ◽  
Idh Mutations ◽  
Genomic Characterization

The genomic characterization of acute myeloid leukemia (AML) by DNA sequencing has illuminated subclasses of the disease, with distinct driver mutations, that might be responsive to targeted therapies. Approximately 15-23% of AML genomes harbor mutations in one of two isoforms of isocitrate dehydrogenase (IDH1 or IDH2). These enzymes are constitutive mediators of basic cellular metabolism, but their mutated forms in cancer synthesize an abnormal metabolite, 2- hydroxyglutarate, that in turn acts as a competitive inhibitor of multiple gene regulatory enzymes. As a result, leukemic IDH mutations cause changes in genome structure and gene activity, culminating in an arrest of normal myeloid differentiation. These discoveries have motivated the development of a new class of selective small molecules with the ability to inhibit the mutant IDH enzymes while sparing normal cellular metabolism. These agents have shown promising anti-leukemic activity in animal models and early clinical trials, and are now entering Phase 3 study. This review will focus on the growing preclinical and clinical data evaluating IDH inhibitors for the treatment of IDH-mutated AML. These data suggest that inducing cellular differentiation is central to the mechanism of clinical efficacy for IDH inhibitors, while also mediating toxicity for patients who experience IDH Differentiation Syndrome. Ongoing trials are studying the efficacy of IDH inhibitors in combination with other AML therapies, both to evaluate potential synergistic combinations as well as to identify the appropriate place for IDH inhibitors within existing standard-of-care regimens.

scholarly journals Synthesis and Piezoelectric Characterization of UV-Curable Nanocellulose/ZnO/AlN Polymeric Flexible Films for Green Energy Generation Applications

Proceedings ◽  
2020 ◽  
Vol 56 (1) ◽  
pp. 36
Author(s):  
Maria Assunta Signore ◽  
Giulio Malucelli ◽  
Donatella Duraccio ◽  
Chiara De Pascali ◽  
Ambra Fioravanti ◽  
...  
Keyword(s):  
Energy Generation ◽  
Green Energy ◽  
Nitride Film ◽  
Cantilever Beams ◽  
Functional Coatings ◽  
Uv Curable ◽  
Mass Insertion ◽  
Flexible Films ◽  
Piezoelectric Behavior

In this work, the fabrication of composites consisting of piezoelectric ZnO ceramic nanostructures and nanocellulose fillers in a UV-cured acrylic matrix has been exploited for the design of new functional coatings for green energy generation. The piezoelectric behavior was investigated at different accelerations applied to cantilever beams. The piezoelectric signal generated by the different ZnO nanostructures was improved by aluminum nitride film integration on the beam and proof mass insertion at the tip.

Electrical Characterization of InAs/(GaIn)Sb Infrared Superlattice Photodiodes for the 8 to 12νm Range

1999 ◽  
Vol 607 ◽  
Author(s):  
L. Bürkle ◽  
F. Fuchs ◽  
R. Kiefer ◽  
W. Pletschen ◽  
R. E. Sah ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Cutoff Wavelength ◽  
Saturation Current ◽  
Diffusion Limited ◽  
Saturation Current Density ◽  
Out Of Plane ◽  
Reverse Saturation Current ◽  
The Magnetic Field ◽  
Diode Current

AbstractInAs/(GaIn)Sb superlattice photodiodes with a cutoff wavelength of 8.711μm show adynamic impedance of R0A= 1.5 kωcm2at 77 K and a responsivity of 2 A/W, corresponding to a detectivity of D*= 1 x 1012 cmv√Hz/W. Diffusion limited performance is observed above 100 K. At lower temperatures the diodesare limited by generation-recombination currents. An analysis of the influence of different diode sidewall passivations on the surface contribution to the diode leakage current is presented. The out-of-plane electron mobility as well as the relative contributions of the electron and hole diffusion currents to the diode current were determined by a measurement of the magnetic field dependence of the reverse saturation current density of the diodes

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