http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Mehdi Simiari (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Real-time 14N NQR-based sodium nitrite analysis in a noisy field
Sharifi Mohammad Saleh,송호승,Afarideh Hossein,미트라게게르치,Simiari Mehdi 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.12
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
-
Artificial neural network-based sodium nitrite NQR analysis in an urban noisy environment
Mohammad Saleh Sharifi A. M.,Hossein Afarideh,Mitra Ghergherehchi,Mehdi Simiari 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.3
Using the nuclear quadrupole resonance procedure in non-shielded environments requires special measures. For this purpose, noise reduction and interference suppression algorithms have been used to increase signal-to-noise and interference ratio or SNIR. For this aim, two types of antennas are considered, the ferrite core coil antenna as the main antenna receives the free induction decay or FID signal, radio frequency interference or RFI, and noise, and the omnidirectional auxiliary antenna receives the RFI and noise as the algorithm reference noise. To perform the noise and interference cancelation, the weighting factors in auxiliary antenna data are so important, that an artifcial neural network or ANN model has been used to increase the SNIR. In this research, sodium nitrite has been used as a sample, then algorithms have been tested in a nonshielded environment. The resonant frequency of the 200 g sample, by the signal-to-noise ratio improvement of 18.889 dB, the signal-to-interference ratio improvement of 24.819 dB, and the FID signal amplifcation of 16.925 dB, were measured at 4.649 MHz. The main technique in this study was to use an auxiliary antenna to estimate the noise and interference and compute the learned weighting factor before sending the NQR pulse.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
