Abstract: An electrochemical gas sensor for detecting a specific gas being measured with a plurality of electrodes (21, 3, 4), an electrolyte (7) and a gas-permeable membrane (9) has a reduced cross sensitivity with respect to interfering gases, a short response time and high sensitivity for the measured gas without the service life being reduced. The measuring electrode is a layer of doped diamond thin (21) on a porous substrate (22), where the gas-permeable memebrane is disposed over the measuring electrode to permit passage therethru of the gas being measured.

Abstract: Method and apparatus are provided for a non-invasive bubble measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as bubbles over a selectable range of bubble sizes of interest. A selected measurement volume in which bubbles may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite bubbles to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which bubbles may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant bubble.