Characterization of Work per Volume Density of VO2-Based MEMS Actuators

2012 ◽  
Author(s):  
Emmanuelle Merced ◽  
Jun Zhang ◽  
Xiaobo Tan ◽  
Nelson Sepúlveda
Keyword(s):  
Smart Materials ◽  
Figure Of Merit ◽  
Volume Density ◽  
Hysteretic Behavior ◽  
Contact Mode ◽  
Thermally Induced ◽  
Mems Actuators ◽  
Different Temperatures ◽  
Insulator Phase Transition

Vanadium dioxide (VO2)-coated silicon microcantilevers have gained attention due to the large stress produced during VO2’s thermally induced metal-to-insulator phase transition, which produces a curvature change of over ∼2,000 m−1. Work per volume density is an important figure of merit used to compare the performance of smart materials in micro-actuation. In this paper, the work per volume density of five fully actuated VO2-coated microcantilevers was calculated based on experimentally measured force vs. displacement curves obtained from an AFM operated in contact mode. The work per volume density for the five microactuators was found to be similar, which is around ∼1.5×104 J/m3. The work per volume density of a single microactuator was also obtained under different temperatures across the material’s transition, which exhibits the hysteretic behavior during the heating-cooling cycle.

Low Dimensional Approximations to Ferroelastic Dynamics and Hysteretic Behavior Due to Phase Transformations

2010 ◽  
Vol 77 (3) ◽  
Author(s):  
Linxiang X. Wang ◽  
Roderick V. N. Melnik
Keyword(s):  
Phase Transformations ◽  
Landau Theory ◽  
Hysteretic Behavior ◽  
Dimensional Model ◽  
Ginzburg Landau ◽  
Thermally Induced ◽  
Different Temperatures ◽  
Martensite Transformations ◽  
Low Dimensional Approximations ◽  
Low Dimensional

In this paper, a low dimensional model is constructed to approximate the nonlinear ferroelastic dynamics involving mechanically and thermally-induced martensite transformations. The dynamics of the first order martensite transformation is first modeled by a set of nonlinear coupled partial differential equations (PDEs), which is obtained by using the modified Ginzburg–Landau theory. The Chebyshev collocation method is employed for the numerical analysis of the PDE model. An extended proper orthogonal decomposition is then carried out to construct a set of empirical orthogonal eigenmodes of the dynamics, with which system characteristics can be optimally approximated (in a specified sense) within a range of different temperatures and under various mechanical and thermal loadings. The performance of the low dimensional model is analyzed numerically. Results on the dynamics involving mechanically and thermally-induced phase transformations and the hysteresis effects induced by such transformations are presented.

Advanced characterization of a W-band phase shifter based on liquid crystals and MEMS technology

2012 ◽  
Vol 4 (3) ◽  
pp. 379-386 ◽  
Author(s):  
Carsten Fritzsch ◽  
Flavio Giacomozzi ◽  
Onur Hamza Karabey ◽  
Saygin Bildik ◽  
Sabrina Colpo ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Phase Shifter ◽  
Advanced Characterization ◽  
Differential Phase Shift ◽  
Mems Switches ◽  
W Band ◽  
Input Matching ◽  
Different Temperatures ◽  
Mems Technology

In this paper, we present a continuously tunable phase shifter realized in MEMS technology. Varactors with liquid crystal as a tunable dielectric layer underneath gold bridges are used to build a loaded line phase shifter. Measurements show that the phase shifter has a differential phase shift of 92°, a figure of merit (FoM) of 42°/dB and an input matching of −19 dB at 76 GHz.The tuning speed of the phase shifter is measured at different temperatures between 10 and 50°C. The realized phase shifter can be used in combination with MEMS switches in order to build a 360° tunable reflection phase shifter.

Applications of ultramicrotomy for materials characterization

1993 ◽  
Vol 51 ◽  
pp. 232-233
Author(s):  
R.T. Blackham ◽  
J.J. Haugh ◽  
C.W. Hughes ◽  
M.G. Burke
Keyword(s):  
Materials Science ◽  
Microstructural Analysis ◽  
Analytical Electron Microscopy ◽  
Austenitic Stainless Steels ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Thermally Induced ◽  
Radiation Induced ◽  
Characterization Of Materials

Essential to the characterization of materials using analytical electron microscopy (AEM) techniques is the specimen itself. Without suitable samples, detailed microstructural analysis is not possible. Ultramicrotomy, or diamond knife sectioning, is a well-known mechanical specimen preparation technique which has been gaining attention in the materials science area. Malis and co-workers and Glanvill have demonstrated the usefulness and applicability of this technique to the study of a wide variety of materials including Al alloys, composites, and semiconductors. Ultramicrotomed specimens have uniform thickness with relatively large electron-transparent areas which are suitable for AEM anaysis.Interface Analysis in Type 316 Austenitic Stainless Steel: STEM-EDS microanalysis of grain boundaries in austenitic stainless steels provides important information concerning the development of Cr-depleted zones which accompany M23C6 precipitation, and documentation of radiation induced segregation (RIS). Conventional methods of TEM sample preparation are suitable for the evaluation of thermally induced segregation, but neutron irradiated samples present a variety of problems in both the preparation and in the AEM analysis, in addition to the handling hazard.

Detection and Characterization of an Electrical Failure Induced during Laser Ablation of Packages

2008 ◽  
Author(s):  
P. Schwindenhammer ◽  
H. Murray ◽  
P. Descamps ◽  
P. Poirier
Keyword(s):  
Laser Ablation ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
Ablation Process ◽  
Thermally Induced ◽  
Electrical Failure ◽  
Electrical Phenomenon ◽  
Semiconductor Packages ◽  
Complex Semiconductor

Abstract Decapsulation of complex semiconductor packages for failure analysis is enhanced by laser ablation. If lasers are potentially dangerous for Integrated Circuits (IC) surface they also generate a thermal elevation of the package during the ablation process. During measurement of this temperature it was observed another and unexpected electrical phenomenon in the IC induced by laser. It is demonstrated that this new phenomenon is not thermally induced and occurs under certain ablation conditions.

Synthesis and Characterization of Nanocrystalline ZnO Powders by a Direct Thermal Decomposition Route Using Zinc Nitrate Hexahydrate

2013 ◽  
Vol 770 ◽  
pp. 68-71 ◽  
Author(s):  
Supphadate Sujinnapram ◽  
Uraiphorn Termsuk ◽  
Atcharawan Charoentam ◽  
Sutthipoj Sutthana
Keyword(s):  
Thermal Decomposition ◽  
Crystallization Temperature ◽  
Zinc Nitrate ◽  
Zinc Nitrate Hexahydrate ◽  
Absorption Peak ◽  
Synthesis And Characterization ◽  
Nitrate Hexahydrate ◽  
Different Temperatures ◽  
Zno Powders

The nanocrystalline ZnO powders were synthesized by a direct thermal decomposition using zinc nitrate hexahydrate as starting materials. The precursor was characterized by TG-DTA to determine the thermal decomposition and crystallization temperature which was found to be at 325 oC. The precursors were calcined at different temperatures of 400, 500, and 600°C for 4 h. The structure of the prepared samples was studied by XRD, confirming the formation of wurtzite structure. The synthesized powders exhibited the UV absorption below 400 nm (3.10 eV) with a well defined absorption peak at around 285 nm (4.35 eV). The estimated direct bandgaps were obtained to be 3.19, 3.16, and 3.14 eV for the ZnO samples thermally decomposed at 400, 500, and 600°C, respectively.

Wear Behavior and Structural Characterization of a Nitrogen Implanted Ti6Al4V Alloy at Different Temperatures

1983 ◽  
Vol 27 ◽  
Author(s):  
R. Martinella ◽  
G. Chevallard ◽  
C. Tosello
Keyword(s):  
Wear Resistance ◽  
Structural Characterization ◽  
Wear Behavior ◽  
Hardened Layer ◽  
Structural Modifications ◽  
Theory Comparison ◽  
Different Temperatures ◽  
Nitrogen Ions ◽  
Wear Tests

ABSTRACTMechanically polished Ti6Al4V samples were implanted with 100 key nitrogen ions to a fluence of 5.1017 ions/cm2 at two different bulk tenneratures: 370°C and 470°C. Wear tests were carried out with a reciprocating slidina tribotester. Structural modifications and wear morphologies were studied by TEM and SEM. 370°C implanted sample showed the same wear behavior as unimplanted ones, while 470°C implanted sample showed better wear resistance because of a TiN hardened layer. Correlations- between microstructural modifications, wear behavior and mechanisms are reported: results agree with the delamination theory. Comparison with ion- and gas-nitrided samples are presented.

Synthesis and characterization of silver nanoparticle nanocomposite thin films with thermally induced surface morphology changes

2015 ◽  
Vol 159 ◽  
pp. 118-121 ◽  
Author(s):  
Ernandes T. Tenório-Neto ◽  
Marcos R. Guilherme ◽  
Manuel E.G. Winkler ◽  
Lucio Cardozo-Filho ◽  
Stéphani C. Beneti ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Silver Nanoparticle ◽  
Synthesis And Characterization ◽  
Thermally Induced ◽  
Nanocomposite Thin Films ◽  
Morphology Changes

Kinetic and Thermodynamic Characterization of Lignin Peroxidase Isolated from Agaricus bitorqus A66

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Ismat Bibi ◽  
Haq Nawaz Bhatti
Keyword(s):  
Lignin Peroxidase ◽  
Thermal Inactivation ◽  
Specific Activity ◽  
Gel Filtration ◽  
Veratryl Alcohol ◽  
Exchange Chromatography ◽  
Different Temperatures ◽  
Scale Experiment ◽  
Menten Kinetic

This study deals with purification and characterization of lignin peroxidase (LiP) isolated from Agaricus bitorqus A66 during decolorization of NOVASOL Direct Black dye. A laboratory scale experiment was conducted for maximum LiP production under optimal conditions. Purification & fractionation of LiP was performed on DEAE-Sepharose ion exchange chromatography followed by Sephadex G-50 gel filtration. The purified LiP has a specific activity of 519 U/mg with 6.73% activity recover. The optimum pH and temperature of purified LiP for the oxidation of veratryl alcohol were 6.8 and 45 °C, respectively. Michaelis-Menten kinetic constants (Vmax and Km) were determined using different concentrations of veratryl alcohol (1-35 mM). The Km and Vmax were 16.67 mM and 179.2 U/mL respectively, for veratryl alcohol oxidation as determined from the Lineweaver-Burk plot. Thermal inactivation studies were carried out at different temperatures to check the thermal stability of the enzyme. Enthalpy of activation decreased where Free energy of activation for thermal denaturation increased at higher temperatures. A possible explanation for the thermal inactivation of LiP at higher temperatures is also discussed.

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