The adsorption and hydrogenation processes of CO on Rh-based catalyst were studied by in situ high-pressure (HP) MAS NMR techniques under batch-like conditions. ²⁹Si MAS NMR spectra showed that the silanol concentrations of the support Silicate-1 were reduced after impregnation of metal species. After introduction of ¹³CO/H₂ below 200 ℃, only the average exchanged signal of CO between gaseous CO, linearly adsorbed CO and dicarbonyl adsorbed CO was observed on Rh/Silicate-1; while the titled adsorbed CO appeared on Rh-Mn/Silicate-1 or Rh-Mn-Li/Silicate-1. So, the addition of Mn or MnLi could enhance the CO adsorption. Under batchlike condition, high-pressure ¹³C MAS NMR showed that the CO/H₂ reactants could only be converted to CO₂ and CH₄ on Rh/Silicate-1, while only CO2 appeared on Rh-Mn-Li/Silicate-1 at relatively lower temperatures. Meanwhile, ¹H MAS NMR showed the obvious decrease of silanol groups after reaction that indicated CO could react with silanol groups to produce CO₂.

The major ¹H  and ¹³C NMR resonance of polyamide66 in solution were assigned. Relaxation time of ¹H resonance was measured at different temperatures and different concentrations, providing information about molecular motion of the polyamide chains in solution. The interactions between polyamide66 chain segments were found gradually weakened with increasing temperature. This led to dissociation of hydrogen bonding among the polyamide66 chain segments, and binding of solvent molecules to the dissociated free -CO and -NH groups in polyamide66 molecules. The main chains of polyamide66 coiled and aggregated with a shape of random clew with a part of the solvent molecules imbedded, restricting the motions. With increasing concentration, the distances among protons decreased, resulting in strengthened interactions among polyamide66 chain segments, entanglement of the main chains and restricted motions for the macromolecules.

Thermometry in vivo is one of the most important techniques in minimally invasive thermotherapy. Magnetic resonance imaging is ideal for thermometry measurement in vivo since it has advantageous features such as non-invasiveness, high spatial resolution, good softtissue contrast, three-dimensional imaging capability, and intra-operative temperature assessment capacity. However, it is essential to validate and calibrate MRI-based thermometry with independent measurement made by MR-compatible thermometers. In this paper, we present the design and applications of a MR-compatible thermometer, which is simple to implement and has a low cost. The thermometer consists of a general thermocouple and an electronic thermometry device, and has an accuracy about ±0.5 ℃ at the temperature range from 39 ℃ to 79 ℃. Experimental results showed that there was no significant quality degradation to the MR images while the thermometer being in operation. The MR-compatible thermometer proposed is especially suitable for use in combination with low-field MRI-based thermometry.

A versatile digital gradient calculation module with high integration level was developed for magnetic resonance imaging. Based on a single field programmable gate array (FPGA) system, this apparatus operates real-time calculations of the gradient waveforms for oblique acquisition and preemphasis with a 16-bit parallel interface. Gradient profiles from the G_X, G_Y and G_Z channels are stored in the FPGA embedded memory blocks, and loaded via the parallel interface. High-performance digital waveform preemphasis is achieved by iteratively implementing a scattered lookahead algorithm for compensation of eddy currents. The system has the merits of high reliability, good universality, small size and low cost, providing a compact and flexible scheme for gradient waveform generation.

The ¹³C NMR chemical shift for a given carbon atom in aliphatic ether molecules was related to the atomic electronegativity, polarizability and steric effects of the substituents. In this study, the relationship between ¹³C NMR chemical shift (δ_C) and the above parameters were established by multiple variable regression using 153 chemical shift values from 23 aliphatic ethers as the training set. The following formula was obtained: δ_C = 121.134 8+94.365 1Q_i-2.082 3Q_iΣα_x-7.634 7S_H-47.614 9S_O, where Q_i is the partial net charge on the given atom, Σα_x is the polarizability of the atoms near the given atom, S_H and S_O are the steric effect parameters. The stability and prediction capacity of the formula were tested using leave-one-out (LOO) cross-validation (cv) method (R_cv=0.998 0, R₂ cv=0.997 7 and S_cv=0.89), and confirmed by predictions of ¹³C NMR chemical shift of 43 different carbon atoms in 4 compounds.

Metabolic changes in bilateral prefrontal cortex and hippocampus of rats with generalized anxiety disorder were investigated by ¹H magnetic resonance spectroscopy (¹H-MRS) performed at 7.0 T. Male Wistar rats were randomized assigned into the control and model groups (n =8 each). Chronic emotional stress-induced anxiety was used as the generalized anxiety disorder model. Behavioral abnormalities in the model rats were assessed with the elevated plus-maze test. Levels of cerebral metabolites, including N-acetyl aspartate (NAA), choline (Cho), creatine (Cr) and glutamate (Glu), in bilateral prefrontal cortex and hippocampus were measured and used to calculate NAA/Cr, Cho/Cr and Glu/Cr ratios. No significant metabolic difference were found between the model rats and the control rats in bilateral hippocampus and left prefrontal cortex. However, the model rats were found to have significantly lower NAA/Cr and Cho/Cr and significantly increased Glu/Cr in right prefrontal cortex, relative to the control rat. It is concluded that chronic anxiety may be associated with imbalance of amino acid neurotransmitters, neuronal injury/loss and intracellular signal transduction abnormalities in the right prefrontal cortex.

The composition and structure of three new polyolefin specialty elastomers, which were propylene-ethylene copolymers, were studied by ¹³C NMR. It was found that propylene and ethylene underwent atactic polymerization in the elastomers and the weight percentage of ethylene monomer was lower than 20 wt%. The monomer and sequence distributions and methylene number average sequence length were quantitatively determined. The observed triad distribution agreed with the results predicted with Bernoullian statistical model. The average chain segment length and distribution were calculated according to Bernoullian statistical model and copolymer compositions.

Studying the coal and its liquefaction products provides important information about how to control coal liquefaction. In this study, six kinds of coal were analyzed by element analysis, ¹³C CP/MAS/TOSS NMR spectroscopy and ESR spectroscopy. The results showed that the aromaticity of the coal increased with the carbon content. Higher aromaticity of the coal was associated with higher concentrations of aromatic carbons and free radicals, but with lower g factor. The liquefaction products of coal were analyzed by ESR spectroscopy, and the results were used to estimate structural information of the coal and liquefaction mechanisms.

Reservoir separation factor is an important index relfecting petrophysics, heterogeneity and depositional environment of the reservoir. Separation factor is usually calculated through grading analysis (grain size sorting) and mercury intrusion method (pore throat sorting) in laboratory. Pore throat sorting calculated by NMR method was usually based on calibration curve relating T_2g to separation factor measured by conventional methods. Based on the theory underlying conventional separation factor calculation, and combined with sorting characteristics associated with cumulative T₂ distribution, two new methods were proposed to evaluate reservoir sorting on a single sample. The calculation results of these two methods were found to be consistent with those obtained by other methods.

The displacement process during foam flooding after polymer flooding was studied experimentally with parallel cores with different permeability contrast. The fluid distribution in cores was measured by NMR spectroscopy after water flooding, polymer flooding and foam flooding under different processes and various heterogeneity conditions. The distribution area of the bores from which oil was swept out was calculated. The results showed that foam flooding can sweep bores with a wider range of aperture, and bores in which waterchanneling and/or polymer-channeling may occur. Foam can swept oil out from the bores that cannot be reached by water and polymer flooding. In conclusion, foam flooding can not only improve the oil recovery from low permeability cores but also sweep the oil out from microbores in the cores with high permeability.

The effects of ultra-high magnetic field on Hamiltonian of electronic system of diatom molecule in NMR samples were studied. The interactions between the external magnetic field and the electronic system of the diatom molecule were shown to give correction terms for NMR signals that is proportional to B²₀. Given the result, we proposed a method to measure ultra-high magnetic field strength with NMR signals. 

Monoester-diterpenoid aconines (benzoylaconine, benzoylmesaconine, and benzoylhypaconine were obtained by hydrolysis of corresponding diester-diterpenoid aconines (i.e., aconitine, mesaconitine and hypaconitine). ¹H，¹³C and two-dimensional (including ¹H-¹H COSY, HMQC and HMBC) NMR spectra of the compounds were acquired and assigned. The structures of the compounds were elucidated.

With the ligand field theory, a d³ complete energy matrix in the strong field scheme with trigonal bases was constructed, which include cubic crystal field, coulomb interactions, spin-orbit coupling and low-symmetry crystal field. The energy spectrum of LaAlO₃: Cr³⁺ under low temperature and normal pressure was calculated with the matrix, and the corresponding parameters were obtained. The calculated spectrum was found to be in good agreement with experimental data. The calculated ground state g factor of LaAlO₃: Cr³⁺ was also found to be consistent with the experimental values. With these results, the nature of the bonding interaction between Cr³⁺ and the ligands was discussed.

Spin-Hamiltonian parameters (g factors g_∥ and g_⊥ and hyperfine structure constants A_∥ and A_⊥) of [Cu(H₂O)₆]²⁺ cluster adsorbed on Al₂O3 powder were calculated using the perturbation theory method and the complete diagonalization (of energy matrix) method. The results from the two methods were found to be in good agreement to each other, and to experimental results. These results showed that both methods can be used to calculate spin-Hamiltonian parameters of ³d₉ ion clusters in crystals. The tetragonal distortion in [Cu(H₂O)₆]²⁺ cluster was also calculated. 

Two bioactive compounds were isolated from Daphniphyllum angustifolium Hutch. and purified by column chromatography with D101 macroporous resin adsorption, Sephadex LH-20 and Pre-HPLC. The compounds were characterized by UV, ESI-MS, ¹H NMR, ¹³C NMR and 2D NMR (HSQC, HMBC and NOESY) techniques. The ¹H NMR and ¹³C NMR signals of the compounds were assigned. Their structures were elucidated as 5,4′-dihydroxyflavanone-7-O-α-L-rhamnopyranosyl (1→2) -β-D-glucopyranoside and 7,4′-dihydroxy-isofavone-8-C-β-D-glucopyranoside, respectively.