The South Pole Acoustic Test Setup (SPATS) is located in the upper part of the optical neutrino observatory IceCube, currently under construction. SPATS consists of four strings at depths between 80m and 500m below the surface of the ice with seven stages per string. Each stage is equipped with an acoustic sensor and a transmitter. Three strings (string A-C) were deployed in the austral summer ...

Low-frequency noise is difficult to deal with by traditional porous material due to its inherent high acoustic impedance. This study seeks to extend the effective range of sound absorption to lower frequencies by filling a low density gas, such as helium, in the porous material. Compared with conventional air-filled absorption material, the helium-filled porous material has a much reduced chara...

First, a brief review of available classes of piezoelectric materials (in particular emergent piezoelectric single crystals) and specific requirements for medical imaging applications is made. Several piezoelectric materials are retained for two specific applications (50 MHz high frequency single element transducer and high density 2D array) to simulate and compare the overall transducer perfor...

In the process of ultrasonic vibration cutting (UVC), acoustic performance parameters machining system change because systems heating up and loads. The changes will affect resonant frequency, impedance, power match system, stability amplitude UVC system. It is hard to monitor online. Based on analysis correlation mechanism between transducer temperature parameters, models resonance static capac...

Nano-structured TiO(2) thin film has been successfully fabricated at room temperature. Using a quarter wavelength characterization method, we have measured the acoustic impedance of this porous film, which can be adjusted from 5.3 to 7.19 Mrayl by curing it at different temperatures. The uniform microstructure and easy fabrication at room temperature make this material an excellent candidate fo...

To achieve best performance in radio frequency (RF) circuits it is necessary to match each active component to the characteristic system impedance. This requirement is also valid for passive surface acoustic wave (SAW) filters and, as used in this application, delay line elements. Matching circuits are commonly built up by inductors and capacitors, arranged as Ltype, PI-type or tee-type network...

An outstanding square slot element, for x-band wireless applications with asymmetric coplanar waveguide fed (CPW) is proposed. Various shapes of metallic strips are utilized as grounded stubs for providing Right Hand Circular Polarization (RHCP) functionality and wide-band properties. By adjusting the proposed stubs and hook-shaped radiator, length and positions, wider impedance band width is o...

refractor ambiguities are big problem in seismic refraction method especially in seismic engineering. there can be hidden subsurface geological phenomena such as hidden faults and shear zones which are not simply predicted by the travel-time graph or some geophysical methods. head wave amplitudes are used to show the resolution of refractor ambiguities and the existence of anisotropy in complex...

In (3) φ is an arbitrary test function and ρ the density of the fluid. In consequence, to calculate the acoustic field and thus, to solve the acoustic wave equation, the impedance Za on the surface Γ has to be known. Hence, a measurement technique to determine the acoustic impedance is of great importance, because a realistic sound field can only be calculated, if the real acoustic impedance at...