Use in surface acoustical wave

Both propagation modes of acoustic waves may be utilized to construct mass-sensitive chemical sensors. Wave propagation through the bulk is the basis of so-called bulk acoustic wave (BAW) devices. Propagation along the surface is used in surface acoustic wave (SAW) sensors. 

Barrier layers for Cu metallization in surface acoustic wave (SAW) devices, which are increasingly used in the information technique and telecommunications industry, have been investigated by SIMS depth profiling in comparison to AES (Auger Electron Spectrometry).125 Development trends in SAW devices focus on smaller structures, higher input power or higher frequency. Two Cu metallization systems (of 150 nm thickness) on a LiNb03 substrate with different barrier layers ... 

The piezo-electric effect of deformations of quartz under alternating current (at a frequency in the order of 10 MHz) is used by coating the crystal with a selectively binding substance, e. g. an antibody. When exposed to the antigen, an antibody-antigen complex will be formed on the surface and shift the resonance frequency of the crystal proportionally to the mass increment which is, in turn, proportional to the antigen concentration. A similar approach is used with surface acoustic wave detectors [142] or with the surface plasmon resonance technology (BIAcore, Pharmacia). 

A new Pt(II) polyyne polymer, P15, prepared from the reaction of cfs-[Pt(PPh3)2Cl2] with l,4-diethynyl-2,5-dihexadecyloxybenzene using the extended one pot polymerization route, was tested for its sensing properties and showed fast and reproducible response to relative humidity variations and methanol vapor in surface acoustic-wave (SAW) sensors.46 A SAW sensor was fabricated from polymer P15 as a sensitive membrane, and the polymer was deposited as thin film on the surface of SAW delay lines implemented on three different piezoelectric substrates. High sensitivity and reproducibility were recorded for such devices. The acoustic characterization of the polymer film was also studied with the aid of theoretical results obtained by the perturbation theory. 

Lithium-Niobate and Lithium-Tantalate Lithium-niobate (LN) and lithium-tantalate (LT) are uniaxial p3Toelectrics, having trigonal structure, with spontaneous polarization arising from asymmetrical displacement of lithium relative to the other ions. These materials Tc values are 1,210 °C and 620 °C, respectively. They are always produced commercially in single-crystal forms. Both are much used for surface acoustic wave devices (e.g., high-frequency filters), while LT is used for pyroelectric detection due to its large pyroelectric coefficient and low permittivity. 

Acoustic droplet ejection refers to the process whereby a focused acoustic beam directed toward a liquid-air interface can cause the ejection of discrete droplets of the liquid. Use of surface acoustic waves (SAW) on a solid upon which sessile droplets are attached can cause the migration of those droplets along the solid surface. Finally, standing acoustic waves in flow channels... 

Nguyen, L.T. and Tsai, C.S. 1977. Efficient wideband guided-wave acoustooptic Bragg diffraction using phased surface acoustic wave array in LiNbOs waveguides. Appl. Opt. 16 1297-1304. 

The processed video is converted to ampHtude modulation of an IF frequency, either on a carrier generated by a crystal oscillator or by a frequency synthesizer. The modulated IF is band-shaped in a vestigial sideband filter using a surface-acoustic-wave (SAW) filter. Envelope delay correction is not required for the SAW filter because of the uniform delay characteristics of the device. Envelope-delay compensation may, however, be needed for other parts of the transmitter. The SAW filter provides many benefits to transmitter designers and operators because it requires no adjustments and is stable with respect to temperature and time. Envelope-delay compensation, however, might be required for other parts of the transmitter. 

Lee, J., et al., 2013. Sensitive and reproducible detection of cardiac troponin I in human plasma using a surface acoustic wave immunosensor. Sens. Actuators B 178, 19-25. Available at http //Unkinghub.elsevier.eom/retrieve/pii/S0925400512012786. 

Conjugated polymers have been used in piezoelectric sensors in two configurations in quartz crystal miaobalance (QCM) sensors and in surface acoustic wave (SAW) sensors. The polymer in this case acts only as an active layer, which tunes the surface properties of piezoelectric crystals and improves both the detection limit (by adsorbing more analyte molecules) and selectivity (by introducing special interaaions with analytes). 

A wide variety of solid-state sensors based on hydrogen-specific palladium, metal oxide semiconductor (MOS), CB, electrochemical, and surface acoustic wave (SAW) technology are used in the industry for several years. Microelectromechanical systems (MEMS), and nanotechnology-based devices for the measurement of hydrogen are the recent developments. These developments are mainly driven by the demands of the fuel cell industry. Solid-state approaches are gaining rapid popularity within the industry due to their low cost, low maintenance, replacements, and flexibility of multiple installations with minimal labor. 

Surface Acoustic Waves (SA Ws). The basic idea of this technique is to use the dependence of the frequency and propagation of surface acoustic waves on mass loading in a film. The porous film has to be deposited on a piezoelectric substrate (quartz), which is then placed into a physisorption setup to condense nitrogen at 77 K. Adsorption and condensation of N2 result in a shift of the oscillation frequency, and thus measurements of the oscillation frequency as a function of N2 partial pressure provide an adsorption-desorption isotherm.30 Although the technique has proven to provide a concise characterization of porous films,29,30 the requirement for the deposition directly onto the SAW piezoelectric substrate represents a certain restriction. 

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