Functional magnetic resonance imaging (fMRI) using the blood oxygenation level dependent (BOLD) contrast is an important noninvasive method to study
the functional activities of the brain. Many fMRI studies, especially the experimental studies，have focused on the mechanisms of the BOLD effect and its relationship with brain functions. Properties of fMRI BOLD response in the primary visual cortex of human brain during visual stimulation have been investigated previously，however the results obtained have been contradictory in terms of whether there is a linear relationship between the response and the stimulus. In this study, we applied event-related fMRI to study the BOLD response in human primary visual cortex to the short visual stimuli with durations of 1、2、3、4、5 and 6 seconds respetively. The results show that generally there is a linear relationship between the BOLD response and the duration of the stimulus.

A propagator method was used to calculate diffusion attenuation of the NMR signal under general nonlinear field gradients. Theoretical expressions of
the attenuation factor were obtained for free and restricted diffusion between two plates. Monte Carlo simulation was performed and the results were compared with the theory. It shows that the theoretical method is appropriate for the free diffusion, as well as the restricted diffusion under the short gradient pulse approximation. Monte Carlo simulation provides an alternate way to quantify the effects of inhomogeneous field gradients used in MRI and NMR.

Based on ab initio HF/6-31G* calculations and the subsequent natural bond orbital analysis, a generalized semiempirical relationship has been tested t
o calculate C-H nuclear spin-spin coupling constants. It is demonstrated that the generalized relationship satisfactorily reproduces experimental ¹J_C-H  values for both cyclic and non-cyclic molecules.

This paper describes the development of an L-band resonator for ESR imaging, some problems encountered in the process of designing and manufacturing are discussed. The resonator is a 3-loop 2-gap re-entrant resonator with a physical size that can accommodate H₂O samples up to 20 mm in diameter and 30 mm in length. The resonance frequency of the unloaded resonator was 1.05 GHz. The Q factors of the resonator were measured under different sample (water) loading. The Q factor for the empty resonator was greater than >1 000. Matching between the resonator and the microwave bridge was obtained with a coupling loop inserted in one of the two lateral arms. The optimal diameter of the coupling loop was determined experimentally. For the unloaded cavity this value was about one third of the arm diameter, while for the loaded cavity it was nearly equal to that of the cavity arm. Using this resonator, we obtained the spatial distribution of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) nitroxide radicals in a sample tube.

Since the χ″ non-linearly changes following the magnetic field H in the ferromagnetic sample,  there is a low field (0～12 mT) non-resonance signal having a comparable strength with that of the ferromagnetic resonance signal. With the ESR spectrometer,  the change dχ″/dH]～H is measured，and then study dynamic magnetization of the alloy ribbon Fe₈₄Zr_3.5Nb_3.5B₈Cu₁. The sample of alloy ribbon is anisotropic,  the easy (magnetization) axis of the sample is in the lateral direction of the ribbons,  and the H is at this direction. It is found that dχ″/dH=0 in the regions of the reversible  (0～2.0 mT) and saturation magnetization (≥9.0 mT). When the domain wall motion is nonreversible, the χ″(H) is the largest value χ_max when the H is 4.2 mT. And χ″is relevant to H² during the domain rotation (Rayleigh region). It is found however in the experiment that the χ″(H) being in proportion to H² and Hⁿ(n≥3) are alternatively formed in  three sections. During this process,  the magnetic fields that the dχ″/dH is constants are 4.8～5.2 mT, 5.8～6.4 mT and 8.0～8.5 mT respectively. The macroscopic phenomenon,  that dχ″/dH equals non-zero constant or not alternatively is a microscopic demonstration that domain wall motion and domain rotation.

A novel 18,19-seco-ursane saponin, aculeoside I (1) was isolated from the leaves of Ilex aculeolata Nakai. 2D NMR methods were used to elucidate its
chemical structure. The structure of the new saponin was determined as 3,19-dihydroxyl-16,21-epoxy-18,19-seco-13(18)-urs-ene-28-oic-acid-19-O-α-
L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside.

4-(4-Hydroxyphenyl)-phthalazin-1-one (DHPZ for short) was synthesized as a poly-condensation monomer, and a series of poly(aryl ether)s was prepared
as high performance engineering plastics from this biphenol-like monomer. To functionalize the polymers containing phthlazinone moieties, chlorine atoms, fluorine atoms and sulfonic acid group were introduced to the structure of 4-(4-Hydroxyphenyl)-phthalazin-1-one and a series of phthalazinone derivatives was obtained. In this paper, the structures of these phthalazinone derivatives have been determined by ¹H NMR, ¹³C NMR and two-dimensional NMR spectroscopy such as gCOSY, gHSQC, and gHMBC. All ¹H and ¹³C absorption peaks have been assigned and reported.

Cefepime is a fourth-generation cephalosporin with an extended spectrum of antibacterial activities. The isomeric compounds of Cefepime produced durin
g synthesis are generally considered impurity of the drug. 1D and 2D NMR methods were used in this study to measure the percentage of the impurity in the Cefepime dihydrochloride sample as a measure of quality control. The ¹H and ¹³C resonance of both Cefepime dihydrochloride and the impurity were assigned, and the percentage of the impurity was determined to be 30.39%.

Two chromone glycosides, undulatoside B(1) and 5,7-dihydroxy-2-methylchromone-7-O-β-D-apiosyl (1→6)-β-D-Glucoside (2), were isolated for the first t
ime from the root of Chinese herb Adina pilulifera. The complete assignments of ¹H and ¹³C NMR chemical shifts were obtained for both compounds by 2D NMR.

The two-dimensional Nuclear Overhauser Effect Spectroscopy (NOESY) technique was successfully applied to investigate the structures and absolute confi
gurations of novel chiral ligands which were derived from D-glucose. The results have also been confirmed by computational optimizing model data.

Photopromoted carbonylation of alkyl halides with carbon dioxide was carried out under ambient conditions using non-precious transition metals catalysts such as [Co(acac)₂, Co(OAc)₂ or CoCl₂]. The ESR method was used to study of the reaction. ESR spectroscopic measurements using DMPO (5,5-dimethyl-1-pyrroline N-oxide) as a spin trapping agent confirmed the formation of carbon dioxide anion radicals (CO^·-₂) in the photopromoted carbonylation of carbon dioxide.

Six new heptaacetyl maltosyl esters were synthesized. IR and ¹H NMR spectra showed that all esters had the same configuration of β-anomer. Alkyl sub
stitutes on benzene showed considerable effects on ¹H chemical shifts and ¹³C chemical shifts of the compounds. The ¹H NMR and ¹³C NMR chemical shifts of the compounds were assigned using both 1D and 2D techniques, including ¹H NMR, ¹³C NMR, ¹H-¹H COSY, gHMQC and gHMBC.

Objective To determine the C-2 conformation of two pair of stereo-isomers of germacranolide type, which are scabertopin and isoscabertopin, isodeoxyel
ephantopin and deoxyelephantopin isolated from Elephantopus scaber. Methods The NOESY technique was used along with ¹H NMR，¹³C NMR and HMQC. Results The differences between the NOESY spectra of the two pairs of stereo-isomers were found. Conclusion The C-2 conformation of the two pairs of stereo-isomers from Elephantopus scaber can be determined through the NOESY technique.

A method for calculating the ¹³C NMR chemical shift of the conjugate double bond in polycyclic compounds was reported in this paper.

The NMR methods for determining the relative and absolute configurations of 8-O-4′Neolignans were reviewed. The relative stereochemistry between C-7
and C-8 should be in the erythro form if the coupling constant between the measured by ¹H NMR is small (J=2.7～5.0 Hz). If the coupling constant me
asured is larger (J=6.0～8.6 Hz), the configuration is in the threo form. With the application of NOE difference spectroscopy, CD assay and Mosher's method, the absolute configuration can be determined.

High-level efficiency is obtained on Varian NMR (Mercury-Plus 300) by opening the instrument to staff and all graduated students who were trained at
 SIOC. We use the Gradient Shimming method and Glide User Interface to simplify the performing process of NMR. Furthermore, in order to accelerate the data process and assure the safety of data, we transfer the spectrum through network and control the instrument by identity recognition system.\=\=