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2007 - 20102
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İndeks: Conference Proceedings Citation Index – Science (CPCI-S) × Konu: Aluminum ×

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  • Küçük Resim
    Yayın
    Thermally assisted OSL from deep traps in Al2O3:C
    (Pergamon-Elsevier Science Ltd, 2010-03) Polymeris, George S.; Raptis, Spyridoula; Afouxenidis, Dimitrios; Tsirliganis, Nestor C.; Kitis, George
    The present work suggests an alternative experimental method in order to not only measure the signal of the deep traps in Al2O3:C without heating the sample to temperatures greater than 500 degrees C, but also use this signal for high dose level dosimetry purposes as well. This method consists of photo transfer OSL measurements performed at elevated temperatures using the blue LEDs (470 nm, FWHM 20 nm) housed at commercial Riso TL/OSL systems, after the sample was previously heated up to 500 degrees C in order to empty its main TL dosimetric trap. The influence of this procedure on specific features such as glow curve shape and sensitivity of the main TL glow peak was also studied.
  • Küçük Resim
    Yayın
    Multiple annular ring capacitive micromachined ultrasonic transducer arrays for forward-looking intravascular ultrasound imaging catheters
    (American Society of Mechanical Engineers (ASME), 2007) Güldiken, Rasim Oytun; Zahorian, Jaime S.; Balantekin, Müjdat; Karaman, Mustafa; Değertekin, Fahrettin Levent
    We investigate multiple-annular-ring CMUT array configuration for forward-looking intravascular ultrasound (FL-IVUS) imaging. This configuration has the potential for independent optimization of each ring and uses the silicon area more effectively without any particular drawback. We designed and fabricated a sample 1mm diameter dual annular ring CMUT test array which consists of 24 transmit and 32 receive elements. For imaging experiments, we designed IC chips that contain 8 transimpedance amplifiers, a multiplexer and a buffer. The real time-pulse echo experiments obtained with designed IC electronics show 26dB Signal to Noise Ratio (SNR) from a 3.5 mm away aluminum reflector in oil. This paper presents our first efforts in obtaining real time imaging with designed IC chips which is one step before CMUT on CMOS implementation.