• Journal of the Korean Chemical Society
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• v.41 no.10
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• pp.519-523
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• 1997

• Proceedings of the Korean Magnestics Society Conference
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• 2012.05a
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• pp.118-119
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• 2012

• Analytical Science and Technology
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• v.10 no.3
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• pp.196-202
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• 1997

New vanadium(V) complex, $(NH_4)_2[VO_2NTA]$, has been synthesized and its structure has been determined by solution and solid-state NMR spectroscopies as well as X-ray crystallography. The unit cell of the monoclinic crystals contains four complexes with $a=6.923(1){\AA}$, $b=8.824(2){\AA}$, $c=19.218(11){\AA}$ and ${\beta}=91.60(3)^{\circ}$ in the space group of $P2_1/n$. The $[VO_2NTA]^{2-}$ anion has distorted octahedral geometry with cis-$VO_2$ moiety. It is confirmed that the octahedral geometry is retained in both of solution and solid-state complexes.

• Journal of the Korean Magnetics Society
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• v.3 no.1
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• pp.13-17
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• 1993

We have studied $CuF_{2}.2H_{2}O$ using $^{1}H$ and $^{19}F$ pulsed nuclear magnetic resonance at 30 MHz. From the data of lineshapes, the spin-lattice relaxation times ($T_1$) and the spin echo decay times, lattice dynamics in the structure is investigated. $T_1$ data from both $^{1}H$ and $^{19}F$ NMR indicate that spin-lattice relaxation is dominated by the paramagnetic ion centers at the Cu sites. The lineshapes at room temperature appear to be strongly affected by exchange narrowing and motional narrowing.

• Journal of the Korean Magnetics Society
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• v.12 no.4
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• pp.137-142
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• 2002

A precision magnetic field was generated by the NMR magnetometer and electromagnet system. The current and field feedback systems are used to control of magnetic field in the electromagnet using computer. Stability of magnetic field according to results that compare field and current feedback, current method is better than 2 times. The stability of magnetic field with current feedback improved 10 times compared with no feedback. This system is used for the calibration of magnetometers and the testing related to magnetic fields.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.93-95
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• 2005

MRS is to measure very small metabolite signals, whose resonant frequencies spread over the chemical shift range characteristic of the measured nucleus. The MR signal originates from the excited volume, which is a column of tissue divided into slices by gradient or rf encoding. The parameters that acquired data affected by TE, TR, and other variables. The higher spatial resolution of 3D CSI compared to SVS and its ability to examine regional metabolite variations for brain study.

• The Journal of Natural Sciences
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• v.8 no.1
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• pp.27-32
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• 1995

Magnetic Resonance Imaging anti-solenoid probes have been constructed for the internal imaging. Signal-to-noise ratios of the images acquired by the anti-solenoid probes were compared with those obtained by commercial probes such as a head coil and a body coil. In terms of the internal imaging, the anti-solenoid probes, constructed in the present study, was performed better than the conventional commercial probes. Also, RF(radio-frequency)-field maps produced by the anti-solenoid probes have been simulated using computers. The possibility of human internal imaging using the anti-solenoid probes has been discussed as well.

• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.117-126
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• 1983

$^13C$ and $^51V$ NMR spectroscopy have been used to study the solution structures of the vanadium (v) complexes formed by ethylenediaminetetraacetic acid (EDTA), trans-cyclohexanediaminetetraacetic acid (CDTA), 1,2-propylenediaminetetraacetic acid (PDTA), ethylenediaminediacetic acid (EDDA), 2-hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentacetic acid (DPTA), and nitrilotriacetic acid (NTA). All of the complexes probably have octahedral structures containiing cis-$VO_2$ core. The coordination of hydroxylethyl group is found to be less favored than that of acetate group. EDDA forms two isomers, ${\alpha}$-cis and ${\beta}$-cis. PDTA also forms two structural isomers due to the methyl group in the ligand.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.628-631
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• 1994

We have studied the paramagnetic $CuF_2$ using the techniques of pulsed nuclear magnetic resonance (NMR). The powder sample revealed two well-separated lines from the distinct $^{19}F$ sites at room temperature. One of the lines showed little frequency shift. However, the other showed a large frequency shift, suggesting electron transfers. Furthermore, the two sites have very short spin-lattice relaxation times $(T_1).$ The frequency-shifted site has the shorter $T_1$ than the unshifted one, reflecting the difference of the electron environments of the two sites.

• Journal of the Korean Chemical Society
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• v.21 no.2
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• pp.94-101
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• 1977

The NMR spectra of 2,4-disubstituted or 2,4,6-trisubstituted anisole derivative were examined to study the chemical shift of the ring proton signal. It was found that the chemical shift of the ring proton nearest to the 2-substituted group was influenced by the deshielding effect of the neighboring substituted groups in order of the Van der Waals radii of those groups. These observations were interpreted as a steric influence of 2-substituted group on the reactivity of the neighboring ring proton itself. The spectroscopical data were presented and the results were discussed with views of the above conceptions.