This paper presents a three-dimensional constitutive model for shape-memory alloys that generalizes the one-dimensional model presented earlier (Sadjadpour and Bhattacharya 2007 Smart Mater. Struct. 16 S51–62). These models build on recent micromechanical studies of the underlying microstructure of shape-memory alloys, and a key idea is that of an effective transformation strain of the martensi...

A mathematical theory of time-dependent dislocation mechanics of unrestricted geometric and material nonlinearity is reviewed. Within a ‘small deformation’ setting, a suite of simplified, but interesting, models, namely a nonlocal Ginzburg Landau, a nonlocal level set, and a nonlocal generalized Burgers equation are derived. In the finite deformation setting, it is shown that an additive decomp...

resonators. Higher order means more complexity in design. A third-order high-Q 300 kHz micromechanical bandpass filter, with Q-adjustment and frequency tuning, is analyzed using a parameterized cell library, "NODAS," for schematic representation and behavioral HDL simulation. An equivalent SPICE model of the filter is derived, which enables simulation in SPICE and comparison to NODAS. Frequency...

OF DOCTORAL DISSERTATION HELSINKI UNIVERSITY OF TECHNOLOGY P.O. BOX 1000, FI-02015 TKK http://www.tkk.fi Author Mika Petteri Koskenvuori Name of the dissertation Microelectromechanical resonators for frequency reference and frequency conversion applications Manuscript submitted 07.12.2007 Manuscript revised 03.03.2008 Date of the defence 04.04.2008 Monograph Article dissertation (summary + orig...

A 10-MHz series resonant micromechanical resonator oscil-lator has been demonstrated using a custom-designed, single-stage, zero-phase-shift sustaining amplifier together with a clamped-clamped beam micromechanical resonator, designed with a relatively large width of 40 µm to achieve substantially lower series motional resistance R x and higher power handling than previous such devices. Using a...

Micromechanical RF filters and reference oscillators based on recently demonstrated vibrating on-chip micromechanical resonators with Q’s >10,000 at 1.5 GHz, are described as an attractive solution to the increasing count of RF components (e.g., filters) expected to be needed by future multi-band wireless devices. With Q’s this high in on-chip abundance, such devices might also enable a paradig...

Chinese Fir wood (Cunninghamia lanceolata (Lamb.) Hook) was subjected to extraction treatments with sodium chlorite (NaClO2) for delignification, as well as with sodium hydroxide (NaOH) at different concentrations for extraction of hemicelluloses. The wood was examined using a Fourier Transform Infrared (FT-IR) spectrometer and microtension technique to track changes in the chemical and the mic...

We present here the behavior of the resonance frequency of porous anodic alumina cantilever arrays during water vapor adsorption and emphasize their possible use in the micromechanical sensing of humidity levels at least in the range of 10-22%. The sensitivity of porous anodic aluminium oxide cantilevers (Δf/Δm) and the humidity sensitivity equal about 56 Hz/pg and about 100 Hz/%, respectively....