• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4570-4575
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• 2023

Noise and Radio-frequency interference or RFI causes a significant restriction on the Free induction Decay or FID signal detection of the Nuclear Quadrupole Resonance procedure. Therefore, using this method in non-isolated environments such as industry and ports requires extraordinary measures. For this purpose, noise reduction algorithms and increasing signal-to-noise-and-interference ratio or SNIR have been used. In this research, sodium nitrite has been used as a sample and algorithms have been tested in a non-isolated environment. The resonant frequencies for the 150 g of test sample were measured at 303 K at about 1 MHz and 3.4 MHz. The main novelty in this study was, (1) using two types of antennas in the receiver to improve adaptive noise and interference cancellation, (2) using a separate helical antenna in the transmitter to eliminate the duplexer, (3) estimating the noise before sending the pulse to calculate the weighting factors and reduce the noise by adaptive noise cancellation, (3) reject the interference by blanking algorithm, (4) pulse integration in the frequency domain to increase the SNR, and (5) increasing the detection speed by new pulse integration technique. By interference rejection and noise cancellation, the SNIR is improved to 9.24 dB at 1 MHz and to 7.28 dB at 3.4 MHz, and by pulse integration 44.8 dB FID signal amplification is achieved, and the FID signals are detected at 1.057 MHz and 3.402 MHz at room temperature.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.720-726
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• 1999

High voltage pulsed electric fields (PEF) technology is a non-thermal technique which is applicable to extract useful components froms biological materials. This research suggested the possibility for extracting carotenoid pigments from Phaffia rhodozyma by PEF treatments. The yeast cell suspensions were treated with high voltage pulses in a recycled PEF treatment chamber which consists a pair of thin plates of stainless steel adhering to a small chamber with approximately $1{\sim}4\;mm$ gap. A 2.5 log reduction in survivability and more than 98% of electropermeabilization of the yeast cells could be achieved by PEF treatment for $300\;{\mu}s$ with an electric field of 30 kV/cm and pulse duration of $1\;{\mu}s$. When the yeast cell suspended in 0.01% NaCl solution were treated with PEF under various conditions, carotenoid pigments were not extracted. However, the PEF treatment of the yeast cell suspensions in 0.01% $CaCl_2$ solution, have positive effects on the extraction of carotenoid pigments ($27.3\;{\mu}g/g$ of dried yeast).