The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Based on the sensing mechanism of microsensor, a simulation model of a practical silicon beam resonator attached to an E-type round diaphragm and used for measuring pressure is established. The relationship between the basic natural frequency of the beam resonator and the pressure is calculated, analyzed and investigated. As a microsensor FEM is used to study some important simulation results on the...
This paper presents the fourth order vibratory micromachined gyroscope prototype with coupling forces between two modes and the coupling error expression which reveals all the factors affecting the amplitude of the error. A detailed discussion has been performed to determine that the diversity of structures of drive combs and sense combs is the main source of the Quality factor in drive mode varying...
In order to solve the problem of end effect in empirical mode decomposition (EMD), A new method of data extending based on minimum similarity distance is proposed. Firstly, the formulas of matching distance and waveform similarity coefficient are given, and then according to some matching rules, the extending data series which has the optimality minimum similarity distance compared with the ends are...
A new kind of polymer inorganic coagulant-PFSiS (Poly Ferric Silicate Sulphate) coagulants, at different Fe/Si molar ratios and B values (B=OH/Fe) were prepared. Then, the turbidity removal efficiency of PFSiS in treating kaolin suspension was investigated. The results showed that turbidity was removed highly by using PFSiS under the certain conditions. Moreover, FTIR analysis indicated that Si participated...
Fluoralkylpolysiloxane was prepared using perfluoro octyl sulfuryl fluoride and terminal amino-silicone oil as reactants. Then, the isocyanate end capped PU prepolymer was synthesized by reacting isocyanate with a soft segment mixed by active amino-end-capping fluoralkylpolysiloxane and polyether glycol. The fluoralkylpolysiloxane modified PU was obtained after the PU prepolymer was cured by 3,3'-...
Fluorinated organic/inorganic composite pariticles is synthesized by compounding aminosilane (N-beta-aminoethyl)-gamma-aminopropyl trimethoxy silane or N-(beta-aminoethyl)- gamma-aminopropyl methyldimethoxy silane and perfluorinated octyl sulfonic acid fluoride. The structure and properties of products are characterized by FTIR ,1HNMR, TG/DTA, Mastersizer analysis and contact angle, the synthesized...
Resonance Ultrasonic vibrations (RUV) methodology was developed and applied to access mechanical quality of crystalline silicon wafers and solar cells. RUV approach is based on fast non-destructive measurement of specific resonance vibration mode generated in the tested object using external ultrasonic transducer. Crack introduced into the object alters the resonance properties of the mode and allows...
In this paper, a MEMS energy harvester was investigated to scavenge power from ambient vibration source. It was designed to convert low level vibration to electrical power via the piezoelectric effect. The proposed energy harvester was fabricated by patterning Pt electrodes into inter-digital geometry on top of the sol-gel-spin coated Pb(Zr, Ti)O3 thin film for d33 mode on silicon cantilever with...
We have extended measurable pressure range of the thin film Pirani vacuum sensor that is still sensitive above 1 atm. In our thin film Pirani vacuum sensor, our proposed temperature difference sensor of the short circuit Seebeck-current detection type thermocouple is used in order to get extremely high sensitivity, especially in high vacuum range. We have achieved much wider measurable pressure range...
We have designed, fabricated and characterized a MEMS electrostatic energy harvester using an electret as internal bias. The device operates in continuous mode and features a high voltage output, a large travelling distance of a big mass within a compact design using full bulk silicon thickness. The output power is about 1 muW at an acceleration power spectral density of 0.03g2/Hz.
This paper reports experimental results on a dry self-alignment method using a combination of electrostatic fields and mechanical traps to position microsystem chips on a carrier wafer. The electrostatic fields were created by charging SiO2 layers patterned on the carrier and the chips. Pedestal-cavity mating-structures were employed as spacers to avoid premature sticking and ensure unique alignment...
A new approach for the fabrication of large contour-mode single-crystal silicon resonators has been demonstrated without the use of SOI substrates. 24-MHz-disk resonators have been built thanks to industrial facilities dedicated to the integration of passive components on silicon. They exhibit a good compromise between the quality factor Q higher than 50000 and the motional resistance of a few kilo-ohms.
Aiming at the use in low-invasive medical treatments, this paper proposes a realistic imitation of mosquito's proboscis. A silicon needle is electrochemically etched, making the three-dimensionally sharp tip with finely smooth surface. The jagged shank shape is machined by DRIE. The combined needles comprising a central straight needle and two outer jagged needles are fabricated, imitating a labrum...
This paper presents the performance of differentially-driven 7 MHz length-extensional bulk-mode resonators using T-shaped and straight-beam anchors. Resonators with T anchor results in lower motional resistance and higher quality factor of about 717,680 which is six times higher than that achieved for straight-beam anchor. However, it was observed that the length-extensional resonance mode is dependent...
A micromechanical silicon resonant accelerometer (SRA) with micro leverage mechanism amplifying the inertial force is presented. SRA consists of a pair of double-ended tuning forks (DETF), a proof mass and a micro lever mechanism. Firstly, the relation between frequency shift and applied force of DETF is modeled with the classical Bernoulli-Euler beams theory and then simulated by the finite element...
Many theoretical studies prove that the rate gyro can be used for navigation system of the spinning projectile, but these studies are insufficient experimental proofs under condition of the coning motion of the spinning projectile. In this paper, the motion equation of spinning projectile including coning motion and its numerical results are obtained. The silicon micromachined rate gyro is developed...
Depending on the fact that most pillared clays show poor thermal stability, the study on the synthesis of novel Si-pillared montmorillonites (Si-MMT) with high thermal stability have been carried out. Furthermore, powder X-ray diffraction (XRD), Fourier transformation infra-red spectra (FTIR), nitrogen adsorption-desorption isotherms were applied in order to study the thermal stability and mechanisms...
In this paper, specific geometries of resonant cantilevers for scanning force microscopy aimed to reduce sliding between tip and sample have been presented. These cantilevers have been designed for the scanning microdeformation microscope. Flexural and torsional vibration modes have been observed and compared to finite element simulations. Static deflections and dynamic sliding have been studied and...
Microelectromechanical systems (MEMS) are intensively studied since many years due to their high potential performances and their integration possibilities. In particular, electromechanical resonators realized at the CMOS level could allow the emergence of integrated multi-frequency architectures suitable for future multiband wireless communication devices that might require many reference frequencies...
The effects of mechanical shocks on polysilicon MEMS accelerometers are here investigated within the frame of a multi-scale finite element approach. To accurately model MEMS dynamics and possible failure events, three length-scales are explored: macroscale, characterized by stress waves propagating inside the package and eventually impinging upon sensor anchors; mesoscale, characterized by forced...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.