The possibility of identifying liquid substances by their evaporation efficiency from a silicon substrate is investigated. Two sensor designs were used as test models. first rod with thermally insulated side walls, loaded one the ends and probed volumetric acoustic wave. second wafer on surface wave propagating opposite wafer. It shown that in both structures, due to high thermal conductivity silicon, temperature changes evaporating substance are transmitted almost unchanged probing waves,...

Zinc oxide is one of the most popular materials for acoustoelectronic sensors and vibro-piezo-transducers used in nano-piezo-generators. In present paper, thick piezoelectric ZnO films are fabricated on both sides various substrates using magnetron sputtering technique. It shown that main problem double film deposition difference thermal expansion coefficients substrate materials. The solved by decreasing plate temperature up to 140 °C, reducing growing rate 0.8 ± 0.05 μm/h, diminishing...

The detection of the liquid-to-ice transition is an important challenge for many applications. In this paper, a method multi-parameter characterization phase proposed and tested. based on fundamental properties bulk acoustic waves (BAWs). BAWs with shear vertical (SV) or horizontal (SH) polarization cannot propagate in liquids, only solids such as ice. longitudinal (L) polarization, however, can both liquids solids, but different velocities attenuations. Velocities attenuations L-BAWs...

Surface acoustic wave (SAW) sensors have been successfully exploited for the detection of both chemical and physical quantities. In this paper we report more recent results on SAW relative humidity (R.H.). Different interactive materials (CIMs), organic inorganic compounds, are tested their performances in R.H. range between 10 80% reported compared. All devices analysed shown to operate a reversible way, with fairly good repeatibility fast response times. The CIMs produce variety different...

The gas sensing properties of organic polypyrrole (PPS) film, deposited onto LiNbO(3) substrate by Langmuir-Blodgett (LB) technique, have been monitored surface acoustic wave (SAW) delay lines and studied with respect to sensitivity, selectivity, response time, stability, repeatability, aging. SAW PPy elements demonstrate high sensitivity toward NH(3) selectivity against CH(4), CO, H(2), O(2). detectable threshold concentration has estimated as 20 ppm in air; the time is 10s range, recovery...

Attenuation cac versus viscosity eta of adjacent liquid is measured for each normal mode n generated in 30 different plates commercially available, piezoelectric crystals with thickness-to-wavelength ratio the range h/lamda = 0.6 - 2.5. Two modes an optimal combination sensitivity (0.1 dB/mm x cP), insertion loss (<35 dB), and stop-band rejection (>15 dB) are found liquid-loaded 128 degrees Y,X + 90 LiNbO3 1.67. Both suited measurements other sensing tasks viscous liquids. They have...

It is shown that, in spite of the wave radiation into adjacent liquid, a large group Lamb waves are able to propagate along piezoelectric plates (quartz, LiNbO3, LiTaO3) coated with liquid layer (distilled water H2O). When freezes, most group’s increase their losses, essentially forming an acoustic response towards water-to-ice transformation. Partial contributions responses originating from propagation, electro-mechanical transduction, and scattering were estimated compared coupling...

Using plates of weak piezoeletcric crystal (quartz) loaded with various liquids, it is shown that along common modes, whose sensitivity towards different liquid parameters comparable each other, there are some uncommon amplitude responses viscosity η much larger than temperature T and electric conductivity σ. The search the modes selective properties accomplished by varying plate thickness h, orientation, wave length λ, mode order n. It found all possessing property characterized small...

Using acoustic wave modes propagation in piezoelectric plates loaded with conductive liquids, peculiarities of the mode-liquid acoustoelectric interaction are studied. It is found that (i) contrast to bulk and surface waves propagating semiconductors, attenuation not symmetric respect its maximum, (ii) a large increase may be accompanied by small decrease phase velocity vice versa, (iii) valid for "pure" (without beam steering) "not pure" (with modes, as well different orders polarizations,...

Orientation dependences of the phase velocity vn, coupling coefficient Kn(2), and power flow angle Ψ(n) for zero-order high-order acoustic modes are calculated numerically in ST-quartz 128°Y-LiNbO(3) plates with normalized thickness h/λ = 0.1, 0.25, 0.5, 1.0, 1.25, 1.5, 1.67 (n is mode order, θ between propagation direction x-axis, h thickness, λ wavelength). Results calculations experimentally verified using 128°YLiNbO(3) 0°, 30°, 60°, 90° as examples.

In this work, a sensitive coating based on Langmuir-Blodgett (LB) films containing monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) with an immobilized glucose oxidase (GOx) enzyme was created. The immobilization the in LB film occurred during formation monolayer. effect GOx molecules surface properties Langmuir DPPE monolayer investigated. sensory resulting solution various concentrations were studied. It has shown that into leads to rising conductivity increasing...

A new propagation medium-a layered structure composed of a film and plate-is suggested studied, using c-oriented ZnO AlN films on (001), {100}-Si plate, as two opposite examples slow-on-fast fast-on-slow material combinations. For both structures, the modes belonging to Lamb, quasi-longitudinal (QL), Anisimkin Jr.' (AN) families are found. each family, velocities v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> , displacement profiles,...

Acoustic plate modes of different orders n, having equal velocities vn close to that the longitudinal BAW vL, are numerically studied in crystals symmetries. Three families with v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> ~ each at relevant thickness h/λ = (h/λ) , found (h is thickness, λ wavelength): generalized Lamb mode comparable u xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> shear-horizontal...

This paper theoretically and experimentally demonstrates the possibility of detecting five basic tastes (salt, sweet, sour, umami, bitter) using a variety higher-order acoustic waves propagating in piezoelectric plates. Aqueous solutions sodium chloride (NaCl), glucose (C6H12O6), citric acid (C6H8O7), monosodium glutamate (C5H8NO4Na), sagebrush were used as chemicals for simulation each taste. These liquids differed from other terms their physical properties such density, viscosity,...