• 한국초전도학회:학술대회논문집
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• 2007.07a
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• pp.7-7
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• 2007

• Journal of the Korean Magnetics Society
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• v.4 no.1
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• pp.48-51
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• 1994

We have studied the room temperature anisotropy in the high $T_{c}$ superconductor $YBa_{2}Cu_{3}O_{7}$ by means of the $^{63}Cu$ nuclear quadrupole resonance (NQR). For the magnetically oriented powder samples, NQR signals were obtained only when the RF magnetic field is applied perpendicular to the direction of the crystalline c-axis. Significant differences in the spin-lattice relaxation times ($T_{1}$) and the lineshapes were observed between the unoriented powder sample and the magnetically oriented sample.

• Journal of the Korean Magnetics Society
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• v.5 no.2
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• pp.99-102
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• 1995

When the low magnetic field is applied to the synunetry axis of the axial synunetric electric field gradient tensor of the quadrupolar nucleus in the crystal with nuclear spin, I=1, two split resonance frequencies are observed by the Zeeman effect on the nuclear quadrupole resonance. The applied magnetic field is proportional to the difference of the two resonance frequencies and this proportionality constant for the $^{14}N$ of ${(CH_{2})}_{6}N_{4}$ single crystal is 0.16 mT/kHz. The NQR spectrometer is interfaced with a personal computer from which the resonance signals are displayed and the value of magnetic field is obtained directly from the difference of the two resonance frequeocies. The lowestest measured magnetic field was 0.20 mT using this NQR technique.

• Journal of the Korean Chemical Society
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• v.26 no.4
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• pp.205-209
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• 1982

Anisotropic rotation of $CDCl_3$ in neat liquid is investigated by the analysis of ${\nu}_1$ band of Raman spectrum and the diffusion constant($D_{\perp}$) for the tumbling motion is obtained. The diffusion constant ($D_{II}$) for the spinning motion is obtained from the above $D_{\perp}$ value and the chlorine-35 nuclear quadrupole relaxation time. The diffusion constants thus obtained seem to agree very well with the ones obtained from $^2H$ and $^35C$l in NQR results within experimental errors. The data suggest fairly anisotropic character of reorientational motions in neat $CDCl_3$.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.551-554
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• 1989

Quadrupole coupling constants of $^{63}$CU in the high $T_c$ superconductor $YBa_2Cu_3O_7_{-x}$, as determined by NQR or NMR studies, are compared with the values for representative Cu(Ⅱ) complexes determined by analyzing the forbidden lines in their EPR spectra. It is shown that the two NQR lines at 22 and 31 MHz correpsond to the quadrupole coupling constants of a square planar Cu(Ⅱ) complex and a square pyramidal Cu(Ⅱ) complex, respectively.t This result is in agreement with the assignment of these lines to Cu(1) and Cu(2) sites in YBCO based on the NMR spectra of oriented single crystals.

• 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.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.427-431
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• 2007

차세대 지뢰탐지 기술로는 NQR(Nuclear Quadrupole Resonance, 핵4중극자공명), GPR(Ground Penetrating Radar, 지상 침투 레이더)등 이 연구 및 개발 중 이다. 현재 우리나라에서도 이중 GPR을 차세대 지뢰탐지 기술로 연구중에 있다. 그렇지만 지금까지 개발된 GPR 기술을 적용한 지뢰탐지기는 얻어진 2차원 영상에 대해서 육안에 의한 식별만이 가능하여 지뢰 식별이 장시간 소요된다는 단점을 가지고 있다. 이에 본 논문에서는 그러한 문제를 해결하기 위해 주성분 분석법을 적용하여 해결하고, 제안된 시스템이 가능한지 확인하기 위해 유사한 실험 환경을 구성하고, 얻어진 영상을 학습시켜 실제로 얻어진 영상에 대한 분류가 가능한지를 확인하였다.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.208-212
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• 2011

In this work, the calculated nuclear quadrupole coupling constants of $^{17}O$ in some styrylquinoline conformers were presented. The calculations were carried out to find the relationships between the charge distribution of styrylquinolines and their pharmaceutical behavior and to explore the differences among the electronic structures of some conformers of these potent HIV IN inhibitors. Furthermore, the HIV IN inhibitory of R1 and R2 rotamers was compared. On the basis of our results: - Charge density on oxygen atoms of carboxyl moiety has a dominant role in the drug activity. - The a conformer in which a divalent hydrogen atom is a link, has more capability in antiviral drug treatment. - The R1 conformer, as a $Mg^{+2}$ chelating agent, is better than R2 conformer and thus it is more inhibitor of HIV IN.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.247-250
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• 1999

We have performed $^{63,65}$Cu nuclear quadrupole resonance (NQR) measurements on Zn and Ni doped YBa$_2Cu_3O_7$ (YBa$_2Cu_{3-x}M_xO_7$, M=Zn or Ni, x = 0.00 ${\sim}$ 0.09). Doping effects are markedly different in relaxation rates as well as in superconducting transition temperatures. Both the spin-lattice and the spin-spin relaxation rates decrease for Zn doped YBCO. However, those increase for Ni doped YBCO. This contrast in local electronic dynamics provides a clear microscopic evidence that Zn forms no local moment, while Ni develops a local moment. Consequently, the antiferromagnetic spin fluctuation is suppressed by Zn doping whereas it is preserved by Ni doping.